1 /* Optimize by combining instructions for GNU compiler.
2 Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This module is essentially the "combiner" phase of the U. of Arizona
23 Portable Optimizer, but redone to work on our list-structured
24 representation for RTL instead of their string representation.
26 The LOG_LINKS of each insn identify the most recent assignment
27 to each REG used in the insn. It is a list of previous insns,
28 each of which contains a SET for a REG that is used in this insn
29 and not used or set in between. LOG_LINKs never cross basic blocks.
30 They were set up by the preceding pass (lifetime analysis).
32 We try to combine each pair of insns joined by a logical link.
33 We also try to combine triples of insns A, B and C when
34 C has a link back to B and B has a link back to A.
36 LOG_LINKS does not have links for use of the CC0. They don't
37 need to, because the insn that sets the CC0 is always immediately
38 before the insn that tests it. So we always regard a branch
39 insn as having a logical link to the preceding insn. The same is true
40 for an insn explicitly using CC0.
42 We check (with use_crosses_set_p) to avoid combining in such a way
43 as to move a computation to a place where its value would be different.
45 Combination is done by mathematically substituting the previous
46 insn(s) values for the regs they set into the expressions in
47 the later insns that refer to these regs. If the result is a valid insn
48 for our target machine, according to the machine description,
49 we install it, delete the earlier insns, and update the data flow
50 information (LOG_LINKS and REG_NOTES) for what we did.
52 There are a few exceptions where the dataflow information created by
53 flow.c aren't completely updated:
55 - reg_live_length is not updated
56 - reg_n_refs is not adjusted in the rare case when a register is
57 no longer required in a computation
58 - there are extremely rare cases (see distribute_regnotes) when a
60 - a LOG_LINKS entry that refers to an insn with multiple SETs may be
61 removed because there is no way to know which register it was
64 To simplify substitution, we combine only when the earlier insn(s)
65 consist of only a single assignment. To simplify updating afterward,
66 we never combine when a subroutine call appears in the middle.
68 Since we do not represent assignments to CC0 explicitly except when that
69 is all an insn does, there is no LOG_LINKS entry in an insn that uses
70 the condition code for the insn that set the condition code.
71 Fortunately, these two insns must be consecutive.
72 Therefore, every JUMP_INSN is taken to have an implicit logical link
73 to the preceding insn. This is not quite right, since non-jumps can
74 also use the condition code; but in practice such insns would not
84 /* Must precede rtl.h for FFS. */
90 #include "hard-reg-set.h"
92 #include "basic-block.h"
93 #include "insn-config.h"
94 #include "insn-flags.h"
95 #include "insn-codes.h"
96 #include "insn-attr.h"
100 /* It is not safe to use ordinary gen_lowpart in combine.
101 Use gen_lowpart_for_combine instead. See comments there. */
102 #define gen_lowpart dont_use_gen_lowpart_you_dummy
104 /* Number of attempts to combine instructions in this function. */
106 static int combine_attempts
;
108 /* Number of attempts that got as far as substitution in this function. */
110 static int combine_merges
;
112 /* Number of instructions combined with added SETs in this function. */
114 static int combine_extras
;
116 /* Number of instructions combined in this function. */
118 static int combine_successes
;
120 /* Totals over entire compilation. */
122 static int total_attempts
, total_merges
, total_extras
, total_successes
;
124 /* Define a default value for REVERSIBLE_CC_MODE.
125 We can never assume that a condition code mode is safe to reverse unless
126 the md tells us so. */
127 #ifndef REVERSIBLE_CC_MODE
128 #define REVERSIBLE_CC_MODE(MODE) 0
131 /* Vector mapping INSN_UIDs to cuids.
132 The cuids are like uids but increase monotonically always.
133 Combine always uses cuids so that it can compare them.
134 But actually renumbering the uids, which we used to do,
135 proves to be a bad idea because it makes it hard to compare
136 the dumps produced by earlier passes with those from later passes. */
138 static int *uid_cuid
;
139 static int max_uid_cuid
;
141 /* Get the cuid of an insn. */
143 #define INSN_CUID(INSN) \
144 (INSN_UID (INSN) > max_uid_cuid ? insn_cuid (INSN) : uid_cuid[INSN_UID (INSN)])
146 /* Maximum register number, which is the size of the tables below. */
148 static int combine_max_regno
;
150 /* Record last point of death of (hard or pseudo) register n. */
152 static rtx
*reg_last_death
;
154 /* Record last point of modification of (hard or pseudo) register n. */
156 static rtx
*reg_last_set
;
158 /* Record the cuid of the last insn that invalidated memory
159 (anything that writes memory, and subroutine calls, but not pushes). */
161 static int mem_last_set
;
163 /* Record the cuid of the last CALL_INSN
164 so we can tell whether a potential combination crosses any calls. */
166 static int last_call_cuid
;
168 /* When `subst' is called, this is the insn that is being modified
169 (by combining in a previous insn). The PATTERN of this insn
170 is still the old pattern partially modified and it should not be
171 looked at, but this may be used to examine the successors of the insn
172 to judge whether a simplification is valid. */
174 static rtx subst_insn
;
176 /* This is an insn that belongs before subst_insn, but is not currently
177 on the insn chain. */
179 static rtx subst_prev_insn
;
181 /* This is the lowest CUID that `subst' is currently dealing with.
182 get_last_value will not return a value if the register was set at or
183 after this CUID. If not for this mechanism, we could get confused if
184 I2 or I1 in try_combine were an insn that used the old value of a register
185 to obtain a new value. In that case, we might erroneously get the
186 new value of the register when we wanted the old one. */
188 static int subst_low_cuid
;
190 /* This contains any hard registers that are used in newpat; reg_dead_at_p
191 must consider all these registers to be always live. */
193 static HARD_REG_SET newpat_used_regs
;
195 /* This is an insn to which a LOG_LINKS entry has been added. If this
196 insn is the earlier than I2 or I3, combine should rescan starting at
199 static rtx added_links_insn
;
201 /* Basic block number of the block in which we are performing combines. */
202 static int this_basic_block
;
204 /* The next group of arrays allows the recording of the last value assigned
205 to (hard or pseudo) register n. We use this information to see if a
206 operation being processed is redundant given a prior operation performed
207 on the register. For example, an `and' with a constant is redundant if
208 all the zero bits are already known to be turned off.
210 We use an approach similar to that used by cse, but change it in the
213 (1) We do not want to reinitialize at each label.
214 (2) It is useful, but not critical, to know the actual value assigned
215 to a register. Often just its form is helpful.
217 Therefore, we maintain the following arrays:
219 reg_last_set_value the last value assigned
220 reg_last_set_label records the value of label_tick when the
221 register was assigned
222 reg_last_set_table_tick records the value of label_tick when a
223 value using the register is assigned
224 reg_last_set_invalid set to non-zero when it is not valid
225 to use the value of this register in some
228 To understand the usage of these tables, it is important to understand
229 the distinction between the value in reg_last_set_value being valid
230 and the register being validly contained in some other expression in the
233 Entry I in reg_last_set_value is valid if it is non-zero, and either
234 reg_n_sets[i] is 1 or reg_last_set_label[i] == label_tick.
236 Register I may validly appear in any expression returned for the value
237 of another register if reg_n_sets[i] is 1. It may also appear in the
238 value for register J if reg_last_set_label[i] < reg_last_set_label[j] or
239 reg_last_set_invalid[j] is zero.
241 If an expression is found in the table containing a register which may
242 not validly appear in an expression, the register is replaced by
243 something that won't match, (clobber (const_int 0)).
245 reg_last_set_invalid[i] is set non-zero when register I is being assigned
246 to and reg_last_set_table_tick[i] == label_tick. */
248 /* Record last value assigned to (hard or pseudo) register n. */
250 static rtx
*reg_last_set_value
;
252 /* Record the value of label_tick when the value for register n is placed in
253 reg_last_set_value[n]. */
255 static int *reg_last_set_label
;
257 /* Record the value of label_tick when an expression involving register n
258 is placed in reg_last_set_value. */
260 static int *reg_last_set_table_tick
;
262 /* Set non-zero if references to register n in expressions should not be
265 static char *reg_last_set_invalid
;
267 /* Incremented for each label. */
269 static int label_tick
;
271 /* Some registers that are set more than once and used in more than one
272 basic block are nevertheless always set in similar ways. For example,
273 a QImode register may be loaded from memory in two places on a machine
274 where byte loads zero extend.
276 We record in the following array what we know about the nonzero
277 bits of a register, specifically which bits are known to be zero.
279 If an entry is zero, it means that we don't know anything special. */
281 static unsigned HOST_WIDE_INT
*reg_nonzero_bits
;
283 /* Mode used to compute significance in reg_nonzero_bits. It is the largest
284 integer mode that can fit in HOST_BITS_PER_WIDE_INT. */
286 static enum machine_mode nonzero_bits_mode
;
288 /* Nonzero if we know that a register has some leading bits that are always
289 equal to the sign bit. */
291 static char *reg_sign_bit_copies
;
293 /* Nonzero when reg_nonzero_bits and reg_sign_bit_copies can be safely used.
294 It is zero while computing them and after combine has completed. This
295 former test prevents propagating values based on previously set values,
296 which can be incorrect if a variable is modified in a loop. */
298 static int nonzero_sign_valid
;
300 /* These arrays are maintained in parallel with reg_last_set_value
301 and are used to store the mode in which the register was last set,
302 the bits that were known to be zero when it was last set, and the
303 number of sign bits copies it was known to have when it was last set. */
305 static enum machine_mode
*reg_last_set_mode
;
306 static unsigned HOST_WIDE_INT
*reg_last_set_nonzero_bits
;
307 static char *reg_last_set_sign_bit_copies
;
309 /* Record one modification to rtl structure
310 to be undone by storing old_contents into *where.
311 is_int is 1 if the contents are an int. */
317 union {rtx r
; int i
;} old_contents
;
318 union {rtx
*r
; int *i
;} where
;
321 /* Record a bunch of changes to be undone, up to MAX_UNDO of them.
322 num_undo says how many are currently recorded.
324 storage is nonzero if we must undo the allocation of new storage.
325 The value of storage is what to pass to obfree.
327 other_insn is nonzero if we have modified some other insn in the process
328 of working on subst_insn. It must be verified too.
330 previous_undos is the value of undobuf.undos when we started processing
331 this substitution. This will prevent gen_rtx_combine from re-used a piece
332 from the previous expression. Doing so can produce circular rtl
340 struct undo
*previous_undos
;
344 static struct undobuf undobuf
;
346 /* Substitute NEWVAL, an rtx expression, into INTO, a place in some
347 insn. The substitution can be undone by undo_all. If INTO is already
348 set to NEWVAL, do not record this change. Because computing NEWVAL might
349 also call SUBST, we have to compute it before we put anything into
352 #define SUBST(INTO, NEWVAL) \
353 do { rtx _new = (NEWVAL); \
357 _buf = undobuf.frees, undobuf.frees = _buf->next; \
359 _buf = (struct undo *) xmalloc (sizeof (struct undo)); \
362 _buf->where.r = &INTO; \
363 _buf->old_contents.r = INTO; \
365 if (_buf->old_contents.r == INTO) \
366 _buf->next = undobuf.frees, undobuf.frees = _buf; \
368 _buf->next = undobuf.undos, undobuf.undos = _buf; \
371 /* Similar to SUBST, but NEWVAL is an int expression. Note that substitution
372 for the value of a HOST_WIDE_INT value (including CONST_INT) is
375 #define SUBST_INT(INTO, NEWVAL) \
376 do { struct undo *_buf; \
379 _buf = undobuf.frees, undobuf.frees = _buf->next; \
381 _buf = (struct undo *) xmalloc (sizeof (struct undo)); \
384 _buf->where.i = (int *) &INTO; \
385 _buf->old_contents.i = INTO; \
387 if (_buf->old_contents.i == INTO) \
388 _buf->next = undobuf.frees, undobuf.frees = _buf; \
390 _buf->next = undobuf.undos, undobuf.undos = _buf; \
393 /* Number of times the pseudo being substituted for
394 was found and replaced. */
396 static int n_occurrences
;
398 static void init_reg_last_arrays
PROTO((void));
399 static void setup_incoming_promotions
PROTO((void));
400 static void set_nonzero_bits_and_sign_copies
PROTO((rtx
, rtx
));
401 static int can_combine_p
PROTO((rtx
, rtx
, rtx
, rtx
, rtx
*, rtx
*));
402 static int combinable_i3pat
PROTO((rtx
, rtx
*, rtx
, rtx
, int, rtx
*));
403 static rtx try_combine
PROTO((rtx
, rtx
, rtx
));
404 static void undo_all
PROTO((void));
405 static rtx
*find_split_point
PROTO((rtx
*, rtx
));
406 static rtx subst
PROTO((rtx
, rtx
, rtx
, int, int));
407 static rtx simplify_rtx
PROTO((rtx
, enum machine_mode
, int, int));
408 static rtx simplify_if_then_else
PROTO((rtx
));
409 static rtx simplify_set
PROTO((rtx
));
410 static rtx simplify_logical
PROTO((rtx
, int));
411 static rtx expand_compound_operation
PROTO((rtx
));
412 static rtx expand_field_assignment
PROTO((rtx
));
413 static rtx make_extraction
PROTO((enum machine_mode
, rtx
, int, rtx
, int,
415 static rtx extract_left_shift
PROTO((rtx
, int));
416 static rtx make_compound_operation
PROTO((rtx
, enum rtx_code
));
417 static int get_pos_from_mask
PROTO((unsigned HOST_WIDE_INT
, int *));
418 static rtx force_to_mode
PROTO((rtx
, enum machine_mode
,
419 unsigned HOST_WIDE_INT
, rtx
, int));
420 static rtx if_then_else_cond
PROTO((rtx
, rtx
*, rtx
*));
421 static rtx known_cond
PROTO((rtx
, enum rtx_code
, rtx
, rtx
));
422 static int rtx_equal_for_field_assignment_p
PROTO((rtx
, rtx
));
423 static rtx make_field_assignment
PROTO((rtx
));
424 static rtx apply_distributive_law
PROTO((rtx
));
425 static rtx simplify_and_const_int
PROTO((rtx
, enum machine_mode
, rtx
,
426 unsigned HOST_WIDE_INT
));
427 static unsigned HOST_WIDE_INT nonzero_bits
PROTO((rtx
, enum machine_mode
));
428 static int num_sign_bit_copies
PROTO((rtx
, enum machine_mode
));
429 static int merge_outer_ops
PROTO((enum rtx_code
*, HOST_WIDE_INT
*,
430 enum rtx_code
, HOST_WIDE_INT
,
431 enum machine_mode
, int *));
432 static rtx simplify_shift_const
PROTO((rtx
, enum rtx_code
, enum machine_mode
,
434 static int recog_for_combine
PROTO((rtx
*, rtx
, rtx
*, int *));
435 static rtx gen_lowpart_for_combine
PROTO((enum machine_mode
, rtx
));
436 static rtx gen_rtx_combine
PVPROTO((enum rtx_code code
, enum machine_mode mode
,
438 static rtx gen_binary
PROTO((enum rtx_code
, enum machine_mode
,
440 static rtx gen_unary
PROTO((enum rtx_code
, enum machine_mode
,
441 enum machine_mode
, rtx
));
442 static enum rtx_code simplify_comparison
PROTO((enum rtx_code
, rtx
*, rtx
*));
443 static int reversible_comparison_p
PROTO((rtx
));
444 static void update_table_tick
PROTO((rtx
));
445 static void record_value_for_reg
PROTO((rtx
, rtx
, rtx
));
446 static void record_dead_and_set_regs_1
PROTO((rtx
, rtx
));
447 static void record_dead_and_set_regs
PROTO((rtx
));
448 static int get_last_value_validate
PROTO((rtx
*, rtx
, int, int));
449 static rtx get_last_value
PROTO((rtx
));
450 static int use_crosses_set_p
PROTO((rtx
, int));
451 static void reg_dead_at_p_1
PROTO((rtx
, rtx
));
452 static int reg_dead_at_p
PROTO((rtx
, rtx
));
453 static void move_deaths
PROTO((rtx
, rtx
, int, rtx
, rtx
*));
454 static int reg_bitfield_target_p
PROTO((rtx
, rtx
));
455 static void distribute_notes
PROTO((rtx
, rtx
, rtx
, rtx
, rtx
, rtx
));
456 static void distribute_links
PROTO((rtx
));
457 static void mark_used_regs_combine
PROTO((rtx
));
458 static int insn_cuid
PROTO((rtx
));
460 /* Main entry point for combiner. F is the first insn of the function.
461 NREGS is the first unused pseudo-reg number. */
464 combine_instructions (f
, nregs
)
468 register rtx insn
, next
, prev
;
470 register rtx links
, nextlinks
;
472 combine_attempts
= 0;
475 combine_successes
= 0;
476 undobuf
.undos
= undobuf
.previous_undos
= 0;
478 combine_max_regno
= nregs
;
481 = (unsigned HOST_WIDE_INT
*) alloca (nregs
* sizeof (HOST_WIDE_INT
));
482 reg_sign_bit_copies
= (char *) alloca (nregs
* sizeof (char));
484 bzero ((char *) reg_nonzero_bits
, nregs
* sizeof (HOST_WIDE_INT
));
485 bzero (reg_sign_bit_copies
, nregs
* sizeof (char));
487 reg_last_death
= (rtx
*) alloca (nregs
* sizeof (rtx
));
488 reg_last_set
= (rtx
*) alloca (nregs
* sizeof (rtx
));
489 reg_last_set_value
= (rtx
*) alloca (nregs
* sizeof (rtx
));
490 reg_last_set_table_tick
= (int *) alloca (nregs
* sizeof (int));
491 reg_last_set_label
= (int *) alloca (nregs
* sizeof (int));
492 reg_last_set_invalid
= (char *) alloca (nregs
* sizeof (char));
494 = (enum machine_mode
*) alloca (nregs
* sizeof (enum machine_mode
));
495 reg_last_set_nonzero_bits
496 = (unsigned HOST_WIDE_INT
*) alloca (nregs
* sizeof (HOST_WIDE_INT
));
497 reg_last_set_sign_bit_copies
498 = (char *) alloca (nregs
* sizeof (char));
500 init_reg_last_arrays ();
502 init_recog_no_volatile ();
504 /* Compute maximum uid value so uid_cuid can be allocated. */
506 for (insn
= f
, i
= 0; insn
; insn
= NEXT_INSN (insn
))
507 if (INSN_UID (insn
) > i
)
510 uid_cuid
= (int *) alloca ((i
+ 1) * sizeof (int));
513 nonzero_bits_mode
= mode_for_size (HOST_BITS_PER_WIDE_INT
, MODE_INT
, 0);
515 /* Don't use reg_nonzero_bits when computing it. This can cause problems
516 when, for example, we have j <<= 1 in a loop. */
518 nonzero_sign_valid
= 0;
520 /* Compute the mapping from uids to cuids.
521 Cuids are numbers assigned to insns, like uids,
522 except that cuids increase monotonically through the code.
524 Scan all SETs and see if we can deduce anything about what
525 bits are known to be zero for some registers and how many copies
526 of the sign bit are known to exist for those registers.
528 Also set any known values so that we can use it while searching
529 for what bits are known to be set. */
533 /* We need to initialize it here, because record_dead_and_set_regs may call
535 subst_prev_insn
= NULL_RTX
;
537 setup_incoming_promotions ();
539 for (insn
= f
, i
= 0; insn
; insn
= NEXT_INSN (insn
))
541 uid_cuid
[INSN_UID (insn
)] = ++i
;
545 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
547 note_stores (PATTERN (insn
), set_nonzero_bits_and_sign_copies
);
548 record_dead_and_set_regs (insn
);
551 for (links
= REG_NOTES (insn
); links
; links
= XEXP (links
, 1))
552 if (REG_NOTE_KIND (links
) == REG_INC
)
553 set_nonzero_bits_and_sign_copies (XEXP (links
, 0), NULL_RTX
);
557 if (GET_CODE (insn
) == CODE_LABEL
)
561 nonzero_sign_valid
= 1;
563 /* Now scan all the insns in forward order. */
565 this_basic_block
= -1;
569 init_reg_last_arrays ();
570 setup_incoming_promotions ();
572 for (insn
= f
; insn
; insn
= next
? next
: NEXT_INSN (insn
))
576 /* If INSN starts a new basic block, update our basic block number. */
577 if (this_basic_block
+ 1 < n_basic_blocks
578 && basic_block_head
[this_basic_block
+ 1] == insn
)
581 if (GET_CODE (insn
) == CODE_LABEL
)
584 else if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i')
586 /* Try this insn with each insn it links back to. */
588 for (links
= LOG_LINKS (insn
); links
; links
= XEXP (links
, 1))
589 if ((next
= try_combine (insn
, XEXP (links
, 0), NULL_RTX
)) != 0)
592 /* Try each sequence of three linked insns ending with this one. */
594 for (links
= LOG_LINKS (insn
); links
; links
= XEXP (links
, 1))
595 for (nextlinks
= LOG_LINKS (XEXP (links
, 0)); nextlinks
;
596 nextlinks
= XEXP (nextlinks
, 1))
597 if ((next
= try_combine (insn
, XEXP (links
, 0),
598 XEXP (nextlinks
, 0))) != 0)
602 /* Try to combine a jump insn that uses CC0
603 with a preceding insn that sets CC0, and maybe with its
604 logical predecessor as well.
605 This is how we make decrement-and-branch insns.
606 We need this special code because data flow connections
607 via CC0 do not get entered in LOG_LINKS. */
609 if (GET_CODE (insn
) == JUMP_INSN
610 && (prev
= prev_nonnote_insn (insn
)) != 0
611 && GET_CODE (prev
) == INSN
612 && sets_cc0_p (PATTERN (prev
)))
614 if ((next
= try_combine (insn
, prev
, NULL_RTX
)) != 0)
617 for (nextlinks
= LOG_LINKS (prev
); nextlinks
;
618 nextlinks
= XEXP (nextlinks
, 1))
619 if ((next
= try_combine (insn
, prev
,
620 XEXP (nextlinks
, 0))) != 0)
624 /* Do the same for an insn that explicitly references CC0. */
625 if (GET_CODE (insn
) == INSN
626 && (prev
= prev_nonnote_insn (insn
)) != 0
627 && GET_CODE (prev
) == INSN
628 && sets_cc0_p (PATTERN (prev
))
629 && GET_CODE (PATTERN (insn
)) == SET
630 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (insn
))))
632 if ((next
= try_combine (insn
, prev
, NULL_RTX
)) != 0)
635 for (nextlinks
= LOG_LINKS (prev
); nextlinks
;
636 nextlinks
= XEXP (nextlinks
, 1))
637 if ((next
= try_combine (insn
, prev
,
638 XEXP (nextlinks
, 0))) != 0)
642 /* Finally, see if any of the insns that this insn links to
643 explicitly references CC0. If so, try this insn, that insn,
644 and its predecessor if it sets CC0. */
645 for (links
= LOG_LINKS (insn
); links
; links
= XEXP (links
, 1))
646 if (GET_CODE (XEXP (links
, 0)) == INSN
647 && GET_CODE (PATTERN (XEXP (links
, 0))) == SET
648 && reg_mentioned_p (cc0_rtx
, SET_SRC (PATTERN (XEXP (links
, 0))))
649 && (prev
= prev_nonnote_insn (XEXP (links
, 0))) != 0
650 && GET_CODE (prev
) == INSN
651 && sets_cc0_p (PATTERN (prev
))
652 && (next
= try_combine (insn
, XEXP (links
, 0), prev
)) != 0)
656 /* Try combining an insn with two different insns whose results it
658 for (links
= LOG_LINKS (insn
); links
; links
= XEXP (links
, 1))
659 for (nextlinks
= XEXP (links
, 1); nextlinks
;
660 nextlinks
= XEXP (nextlinks
, 1))
661 if ((next
= try_combine (insn
, XEXP (links
, 0),
662 XEXP (nextlinks
, 0))) != 0)
665 if (GET_CODE (insn
) != NOTE
)
666 record_dead_and_set_regs (insn
);
673 total_attempts
+= combine_attempts
;
674 total_merges
+= combine_merges
;
675 total_extras
+= combine_extras
;
676 total_successes
+= combine_successes
;
678 nonzero_sign_valid
= 0;
681 /* Wipe the reg_last_xxx arrays in preparation for another pass. */
684 init_reg_last_arrays ()
686 int nregs
= combine_max_regno
;
688 bzero ((char *) reg_last_death
, nregs
* sizeof (rtx
));
689 bzero ((char *) reg_last_set
, nregs
* sizeof (rtx
));
690 bzero ((char *) reg_last_set_value
, nregs
* sizeof (rtx
));
691 bzero ((char *) reg_last_set_table_tick
, nregs
* sizeof (int));
692 bzero ((char *) reg_last_set_label
, nregs
* sizeof (int));
693 bzero (reg_last_set_invalid
, nregs
* sizeof (char));
694 bzero ((char *) reg_last_set_mode
, nregs
* sizeof (enum machine_mode
));
695 bzero ((char *) reg_last_set_nonzero_bits
, nregs
* sizeof (HOST_WIDE_INT
));
696 bzero (reg_last_set_sign_bit_copies
, nregs
* sizeof (char));
699 /* Set up any promoted values for incoming argument registers. */
702 setup_incoming_promotions ()
704 #ifdef PROMOTE_FUNCTION_ARGS
707 enum machine_mode mode
;
709 rtx first
= get_insns ();
711 for (regno
= 0; regno
< FIRST_PSEUDO_REGISTER
; regno
++)
712 if (FUNCTION_ARG_REGNO_P (regno
)
713 && (reg
= promoted_input_arg (regno
, &mode
, &unsignedp
)) != 0)
714 record_value_for_reg (reg
, first
,
715 gen_rtx (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
717 gen_rtx (CLOBBER
, mode
, const0_rtx
)));
721 /* Called via note_stores. If X is a pseudo that is narrower than
722 HOST_BITS_PER_WIDE_INT and is being set, record what bits are known zero.
724 If we are setting only a portion of X and we can't figure out what
725 portion, assume all bits will be used since we don't know what will
728 Similarly, set how many bits of X are known to be copies of the sign bit
729 at all locations in the function. This is the smallest number implied
733 set_nonzero_bits_and_sign_copies (x
, set
)
739 if (GET_CODE (x
) == REG
740 && REGNO (x
) >= FIRST_PSEUDO_REGISTER
741 /* If this register is undefined at the start of the file, we can't
742 say what its contents were. */
743 && ! REGNO_REG_SET_P (basic_block_live_at_start
[0], REGNO (x
))
744 && GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
)
746 if (set
== 0 || GET_CODE (set
) == CLOBBER
)
748 reg_nonzero_bits
[REGNO (x
)] = GET_MODE_MASK (GET_MODE (x
));
749 reg_sign_bit_copies
[REGNO (x
)] = 1;
753 /* If this is a complex assignment, see if we can convert it into a
754 simple assignment. */
755 set
= expand_field_assignment (set
);
757 /* If this is a simple assignment, or we have a paradoxical SUBREG,
758 set what we know about X. */
760 if (SET_DEST (set
) == x
761 || (GET_CODE (SET_DEST (set
)) == SUBREG
762 && (GET_MODE_SIZE (GET_MODE (SET_DEST (set
)))
763 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (set
)))))
764 && SUBREG_REG (SET_DEST (set
)) == x
))
766 rtx src
= SET_SRC (set
);
768 #ifdef SHORT_IMMEDIATES_SIGN_EXTEND
769 /* If X is narrower than a word and SRC is a non-negative
770 constant that would appear negative in the mode of X,
771 sign-extend it for use in reg_nonzero_bits because some
772 machines (maybe most) will actually do the sign-extension
773 and this is the conservative approach.
775 ??? For 2.5, try to tighten up the MD files in this regard
776 instead of this kludge. */
778 if (GET_MODE_BITSIZE (GET_MODE (x
)) < BITS_PER_WORD
779 && GET_CODE (src
) == CONST_INT
781 && 0 != (INTVAL (src
)
783 << (GET_MODE_BITSIZE (GET_MODE (x
)) - 1))))
784 src
= GEN_INT (INTVAL (src
)
785 | ((HOST_WIDE_INT
) (-1)
786 << GET_MODE_BITSIZE (GET_MODE (x
))));
789 reg_nonzero_bits
[REGNO (x
)]
790 |= nonzero_bits (src
, nonzero_bits_mode
);
791 num
= num_sign_bit_copies (SET_SRC (set
), GET_MODE (x
));
792 if (reg_sign_bit_copies
[REGNO (x
)] == 0
793 || reg_sign_bit_copies
[REGNO (x
)] > num
)
794 reg_sign_bit_copies
[REGNO (x
)] = num
;
798 reg_nonzero_bits
[REGNO (x
)] = GET_MODE_MASK (GET_MODE (x
));
799 reg_sign_bit_copies
[REGNO (x
)] = 1;
804 /* See if INSN can be combined into I3. PRED and SUCC are optionally
805 insns that were previously combined into I3 or that will be combined
806 into the merger of INSN and I3.
808 Return 0 if the combination is not allowed for any reason.
810 If the combination is allowed, *PDEST will be set to the single
811 destination of INSN and *PSRC to the single source, and this function
815 can_combine_p (insn
, i3
, pred
, succ
, pdest
, psrc
)
822 rtx set
= 0, src
, dest
;
824 int all_adjacent
= (succ
? (next_active_insn (insn
) == succ
825 && next_active_insn (succ
) == i3
)
826 : next_active_insn (insn
) == i3
);
828 /* Can combine only if previous insn is a SET of a REG, a SUBREG or CC0.
829 or a PARALLEL consisting of such a SET and CLOBBERs.
831 If INSN has CLOBBER parallel parts, ignore them for our processing.
832 By definition, these happen during the execution of the insn. When it
833 is merged with another insn, all bets are off. If they are, in fact,
834 needed and aren't also supplied in I3, they may be added by
835 recog_for_combine. Otherwise, it won't match.
837 We can also ignore a SET whose SET_DEST is mentioned in a REG_UNUSED
840 Get the source and destination of INSN. If more than one, can't
843 if (GET_CODE (PATTERN (insn
)) == SET
)
844 set
= PATTERN (insn
);
845 else if (GET_CODE (PATTERN (insn
)) == PARALLEL
846 && GET_CODE (XVECEXP (PATTERN (insn
), 0, 0)) == SET
)
848 for (i
= 0; i
< XVECLEN (PATTERN (insn
), 0); i
++)
850 rtx elt
= XVECEXP (PATTERN (insn
), 0, i
);
852 switch (GET_CODE (elt
))
854 /* We can ignore CLOBBERs. */
859 /* Ignore SETs whose result isn't used but not those that
860 have side-effects. */
861 if (find_reg_note (insn
, REG_UNUSED
, SET_DEST (elt
))
862 && ! side_effects_p (elt
))
865 /* If we have already found a SET, this is a second one and
866 so we cannot combine with this insn. */
874 /* Anything else means we can't combine. */
880 /* If SET_SRC is an ASM_OPERANDS we can't throw away these CLOBBERs,
881 so don't do anything with it. */
882 || GET_CODE (SET_SRC (set
)) == ASM_OPERANDS
)
891 set
= expand_field_assignment (set
);
892 src
= SET_SRC (set
), dest
= SET_DEST (set
);
894 /* Don't eliminate a store in the stack pointer. */
895 if (dest
== stack_pointer_rtx
896 /* If we couldn't eliminate a field assignment, we can't combine. */
897 || GET_CODE (dest
) == ZERO_EXTRACT
|| GET_CODE (dest
) == STRICT_LOW_PART
898 /* Don't combine with an insn that sets a register to itself if it has
899 a REG_EQUAL note. This may be part of a REG_NO_CONFLICT sequence. */
900 || (rtx_equal_p (src
, dest
) && find_reg_note (insn
, REG_EQUAL
, NULL_RTX
))
901 /* Can't merge a function call. */
902 || GET_CODE (src
) == CALL
903 /* Don't eliminate a function call argument. */
904 || (GET_CODE (i3
) == CALL_INSN
905 && (find_reg_fusage (i3
, USE
, dest
)
906 || (GET_CODE (dest
) == REG
907 && REGNO (dest
) < FIRST_PSEUDO_REGISTER
908 && global_regs
[REGNO (dest
)])))
909 /* Don't substitute into an incremented register. */
910 || FIND_REG_INC_NOTE (i3
, dest
)
911 || (succ
&& FIND_REG_INC_NOTE (succ
, dest
))
912 /* Don't combine the end of a libcall into anything. */
913 || find_reg_note (insn
, REG_RETVAL
, NULL_RTX
)
914 /* Make sure that DEST is not used after SUCC but before I3. */
915 || (succ
&& ! all_adjacent
916 && reg_used_between_p (dest
, succ
, i3
))
917 /* Make sure that the value that is to be substituted for the register
918 does not use any registers whose values alter in between. However,
919 If the insns are adjacent, a use can't cross a set even though we
920 think it might (this can happen for a sequence of insns each setting
921 the same destination; reg_last_set of that register might point to
922 a NOTE). If INSN has a REG_EQUIV note, the register is always
923 equivalent to the memory so the substitution is valid even if there
924 are intervening stores. Also, don't move a volatile asm or
925 UNSPEC_VOLATILE across any other insns. */
927 && (((GET_CODE (src
) != MEM
928 || ! find_reg_note (insn
, REG_EQUIV
, src
))
929 && use_crosses_set_p (src
, INSN_CUID (insn
)))
930 || (GET_CODE (src
) == ASM_OPERANDS
&& MEM_VOLATILE_P (src
))
931 || GET_CODE (src
) == UNSPEC_VOLATILE
))
932 /* If there is a REG_NO_CONFLICT note for DEST in I3 or SUCC, we get
933 better register allocation by not doing the combine. */
934 || find_reg_note (i3
, REG_NO_CONFLICT
, dest
)
935 || (succ
&& find_reg_note (succ
, REG_NO_CONFLICT
, dest
))
936 /* Don't combine across a CALL_INSN, because that would possibly
937 change whether the life span of some REGs crosses calls or not,
938 and it is a pain to update that information.
939 Exception: if source is a constant, moving it later can't hurt.
940 Accept that special case, because it helps -fforce-addr a lot. */
941 || (INSN_CUID (insn
) < last_call_cuid
&& ! CONSTANT_P (src
)))
944 /* DEST must either be a REG or CC0. */
945 if (GET_CODE (dest
) == REG
)
947 /* If register alignment is being enforced for multi-word items in all
948 cases except for parameters, it is possible to have a register copy
949 insn referencing a hard register that is not allowed to contain the
950 mode being copied and which would not be valid as an operand of most
951 insns. Eliminate this problem by not combining with such an insn.
953 Also, on some machines we don't want to extend the life of a hard
956 This is the same test done in can_combine except that we don't test
957 if SRC is a CALL operation to permit a hard register with
958 SMALL_REGISTER_CLASSES, and that we have to take all_adjacent
961 if (GET_CODE (src
) == REG
962 && ((REGNO (dest
) < FIRST_PSEUDO_REGISTER
963 && ! HARD_REGNO_MODE_OK (REGNO (dest
), GET_MODE (dest
)))
964 /* Don't extend the life of a hard register unless it is
965 user variable (if we have few registers) or it can't
966 fit into the desired register (meaning something special
968 Also avoid substituting a return register into I3, because
969 reload can't handle a conflict with constraints of other
971 || (REGNO (src
) < FIRST_PSEUDO_REGISTER
972 && (! HARD_REGNO_MODE_OK (REGNO (src
), GET_MODE (src
))
973 || (SMALL_REGISTER_CLASSES
974 && ((! all_adjacent
&& ! REG_USERVAR_P (src
))
975 || (FUNCTION_VALUE_REGNO_P (REGNO (src
))
976 && ! REG_USERVAR_P (src
))))))))
979 else if (GET_CODE (dest
) != CC0
)
982 /* Don't substitute for a register intended as a clobberable operand.
983 Similarly, don't substitute an expression containing a register that
984 will be clobbered in I3. */
985 if (GET_CODE (PATTERN (i3
)) == PARALLEL
)
986 for (i
= XVECLEN (PATTERN (i3
), 0) - 1; i
>= 0; i
--)
987 if (GET_CODE (XVECEXP (PATTERN (i3
), 0, i
)) == CLOBBER
988 && (reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (i3
), 0, i
), 0),
990 || rtx_equal_p (XEXP (XVECEXP (PATTERN (i3
), 0, i
), 0), dest
)))
993 /* If INSN contains anything volatile, or is an `asm' (whether volatile
994 or not), reject, unless nothing volatile comes between it and I3,
995 with the exception of SUCC. */
997 if (GET_CODE (src
) == ASM_OPERANDS
|| volatile_refs_p (src
))
998 for (p
= NEXT_INSN (insn
); p
!= i3
; p
= NEXT_INSN (p
))
999 if (GET_RTX_CLASS (GET_CODE (p
)) == 'i'
1000 && p
!= succ
&& volatile_refs_p (PATTERN (p
)))
1003 /* If INSN is an asm, and DEST is a hard register, reject, since it has
1004 to be an explicit register variable, and was chosen for a reason. */
1006 if (GET_CODE (src
) == ASM_OPERANDS
1007 && GET_CODE (dest
) == REG
&& REGNO (dest
) < FIRST_PSEUDO_REGISTER
)
1010 /* If there are any volatile insns between INSN and I3, reject, because
1011 they might affect machine state. */
1013 for (p
= NEXT_INSN (insn
); p
!= i3
; p
= NEXT_INSN (p
))
1014 if (GET_RTX_CLASS (GET_CODE (p
)) == 'i'
1015 && p
!= succ
&& volatile_insn_p (PATTERN (p
)))
1018 /* If INSN or I2 contains an autoincrement or autodecrement,
1019 make sure that register is not used between there and I3,
1020 and not already used in I3 either.
1021 Also insist that I3 not be a jump; if it were one
1022 and the incremented register were spilled, we would lose. */
1025 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
1026 if (REG_NOTE_KIND (link
) == REG_INC
1027 && (GET_CODE (i3
) == JUMP_INSN
1028 || reg_used_between_p (XEXP (link
, 0), insn
, i3
)
1029 || reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i3
))))
1034 /* Don't combine an insn that follows a CC0-setting insn.
1035 An insn that uses CC0 must not be separated from the one that sets it.
1036 We do, however, allow I2 to follow a CC0-setting insn if that insn
1037 is passed as I1; in that case it will be deleted also.
1038 We also allow combining in this case if all the insns are adjacent
1039 because that would leave the two CC0 insns adjacent as well.
1040 It would be more logical to test whether CC0 occurs inside I1 or I2,
1041 but that would be much slower, and this ought to be equivalent. */
1043 p
= prev_nonnote_insn (insn
);
1044 if (p
&& p
!= pred
&& GET_CODE (p
) == INSN
&& sets_cc0_p (PATTERN (p
))
1049 /* If we get here, we have passed all the tests and the combination is
1058 /* Check if PAT is an insn - or a part of it - used to set up an
1059 argument for a function in a hard register. */
1062 sets_function_arg_p (pat
)
1068 switch (GET_CODE (pat
))
1071 return sets_function_arg_p (PATTERN (pat
));
1074 for (i
= XVECLEN (pat
, 0); --i
>= 0;)
1075 if (sets_function_arg_p (XVECEXP (pat
, 0, i
)))
1081 inner_dest
= SET_DEST (pat
);
1082 while (GET_CODE (inner_dest
) == STRICT_LOW_PART
1083 || GET_CODE (inner_dest
) == SUBREG
1084 || GET_CODE (inner_dest
) == ZERO_EXTRACT
)
1085 inner_dest
= XEXP (inner_dest
, 0);
1087 return (GET_CODE (inner_dest
) == REG
1088 && REGNO (inner_dest
) < FIRST_PSEUDO_REGISTER
1089 && FUNCTION_ARG_REGNO_P (REGNO (inner_dest
)));
1098 /* LOC is the location within I3 that contains its pattern or the component
1099 of a PARALLEL of the pattern. We validate that it is valid for combining.
1101 One problem is if I3 modifies its output, as opposed to replacing it
1102 entirely, we can't allow the output to contain I2DEST or I1DEST as doing
1103 so would produce an insn that is not equivalent to the original insns.
1107 (set (reg:DI 101) (reg:DI 100))
1108 (set (subreg:SI (reg:DI 101) 0) <foo>)
1110 This is NOT equivalent to:
1112 (parallel [(set (subreg:SI (reg:DI 100) 0) <foo>)
1113 (set (reg:DI 101) (reg:DI 100))])
1115 Not only does this modify 100 (in which case it might still be valid
1116 if 100 were dead in I2), it sets 101 to the ORIGINAL value of 100.
1118 We can also run into a problem if I2 sets a register that I1
1119 uses and I1 gets directly substituted into I3 (not via I2). In that
1120 case, we would be getting the wrong value of I2DEST into I3, so we
1121 must reject the combination. This case occurs when I2 and I1 both
1122 feed into I3, rather than when I1 feeds into I2, which feeds into I3.
1123 If I1_NOT_IN_SRC is non-zero, it means that finding I1 in the source
1124 of a SET must prevent combination from occurring.
1126 On machines where SMALL_REGISTER_CLASSES is non-zero, we don't combine
1127 if the destination of a SET is a hard register that isn't a user
1130 Before doing the above check, we first try to expand a field assignment
1131 into a set of logical operations.
1133 If PI3_DEST_KILLED is non-zero, it is a pointer to a location in which
1134 we place a register that is both set and used within I3. If more than one
1135 such register is detected, we fail.
1137 Return 1 if the combination is valid, zero otherwise. */
1140 combinable_i3pat (i3
, loc
, i2dest
, i1dest
, i1_not_in_src
, pi3dest_killed
)
1146 rtx
*pi3dest_killed
;
1150 if (GET_CODE (x
) == SET
)
1152 rtx set
= expand_field_assignment (x
);
1153 rtx dest
= SET_DEST (set
);
1154 rtx src
= SET_SRC (set
);
1155 rtx inner_dest
= dest
, inner_src
= src
;
1159 while (GET_CODE (inner_dest
) == STRICT_LOW_PART
1160 || GET_CODE (inner_dest
) == SUBREG
1161 || GET_CODE (inner_dest
) == ZERO_EXTRACT
)
1162 inner_dest
= XEXP (inner_dest
, 0);
1164 /* We probably don't need this any more now that LIMIT_RELOAD_CLASS
1167 while (GET_CODE (inner_src
) == STRICT_LOW_PART
1168 || GET_CODE (inner_src
) == SUBREG
1169 || GET_CODE (inner_src
) == ZERO_EXTRACT
)
1170 inner_src
= XEXP (inner_src
, 0);
1172 /* If it is better that two different modes keep two different pseudos,
1173 avoid combining them. This avoids producing the following pattern
1175 (set (subreg:SI (reg/v:QI 21) 0)
1176 (lshiftrt:SI (reg/v:SI 20)
1178 If that were made, reload could not handle the pair of
1179 reg 20/21, since it would try to get any GENERAL_REGS
1180 but some of them don't handle QImode. */
1182 if (rtx_equal_p (inner_src
, i2dest
)
1183 && GET_CODE (inner_dest
) == REG
1184 && ! MODES_TIEABLE_P (GET_MODE (i2dest
), GET_MODE (inner_dest
)))
1188 /* Check for the case where I3 modifies its output, as
1190 if ((inner_dest
!= dest
1191 && (reg_overlap_mentioned_p (i2dest
, inner_dest
)
1192 || (i1dest
&& reg_overlap_mentioned_p (i1dest
, inner_dest
))))
1194 /* This is the same test done in can_combine_p except that we
1195 allow a hard register with SMALL_REGISTER_CLASSES if SRC is a
1196 CALL operation. Moreover, we can't test all_adjacent; we don't
1197 have to, since this instruction will stay in place, thus we are
1198 not considering increasing the lifetime of INNER_DEST.
1200 Also, if this insn sets a function argument, combining it with
1201 something that might need a spill could clobber a previous
1202 function argument; the all_adjacent test in can_combine_p also
1203 checks this; here, we do a more specific test for this case. */
1205 || (GET_CODE (inner_dest
) == REG
1206 && REGNO (inner_dest
) < FIRST_PSEUDO_REGISTER
1207 && (! HARD_REGNO_MODE_OK (REGNO (inner_dest
),
1208 GET_MODE (inner_dest
))
1209 || (SMALL_REGISTER_CLASSES
&& GET_CODE (src
) != CALL
1210 && ! REG_USERVAR_P (inner_dest
)
1211 && (FUNCTION_VALUE_REGNO_P (REGNO (inner_dest
))
1212 || (FUNCTION_ARG_REGNO_P (REGNO (inner_dest
))
1214 && sets_function_arg_p (prev_nonnote_insn (i3
)))))))
1215 || (i1_not_in_src
&& reg_overlap_mentioned_p (i1dest
, src
)))
1218 /* If DEST is used in I3, it is being killed in this insn,
1219 so record that for later.
1220 Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the
1221 STACK_POINTER_REGNUM, since these are always considered to be
1222 live. Similarly for ARG_POINTER_REGNUM if it is fixed. */
1223 if (pi3dest_killed
&& GET_CODE (dest
) == REG
1224 && reg_referenced_p (dest
, PATTERN (i3
))
1225 && REGNO (dest
) != FRAME_POINTER_REGNUM
1226 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
1227 && REGNO (dest
) != HARD_FRAME_POINTER_REGNUM
1229 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
1230 && (REGNO (dest
) != ARG_POINTER_REGNUM
1231 || ! fixed_regs
[REGNO (dest
)])
1233 && REGNO (dest
) != STACK_POINTER_REGNUM
)
1235 if (*pi3dest_killed
)
1238 *pi3dest_killed
= dest
;
1242 else if (GET_CODE (x
) == PARALLEL
)
1246 for (i
= 0; i
< XVECLEN (x
, 0); i
++)
1247 if (! combinable_i3pat (i3
, &XVECEXP (x
, 0, i
), i2dest
, i1dest
,
1248 i1_not_in_src
, pi3dest_killed
))
1255 /* Try to combine the insns I1 and I2 into I3.
1256 Here I1 and I2 appear earlier than I3.
1257 I1 can be zero; then we combine just I2 into I3.
1259 It we are combining three insns and the resulting insn is not recognized,
1260 try splitting it into two insns. If that happens, I2 and I3 are retained
1261 and I1 is pseudo-deleted by turning it into a NOTE. Otherwise, I1 and I2
1264 Return 0 if the combination does not work. Then nothing is changed.
1265 If we did the combination, return the insn at which combine should
1269 try_combine (i3
, i2
, i1
)
1270 register rtx i3
, i2
, i1
;
1272 /* New patterns for I3 and I3, respectively. */
1273 rtx newpat
, newi2pat
= 0;
1274 /* Indicates need to preserve SET in I1 or I2 in I3 if it is not dead. */
1275 int added_sets_1
, added_sets_2
;
1276 /* Total number of SETs to put into I3. */
1278 /* Nonzero is I2's body now appears in I3. */
1280 /* INSN_CODEs for new I3, new I2, and user of condition code. */
1281 int insn_code_number
, i2_code_number
, other_code_number
;
1282 /* Contains I3 if the destination of I3 is used in its source, which means
1283 that the old life of I3 is being killed. If that usage is placed into
1284 I2 and not in I3, a REG_DEAD note must be made. */
1285 rtx i3dest_killed
= 0;
1286 /* SET_DEST and SET_SRC of I2 and I1. */
1287 rtx i2dest
, i2src
, i1dest
= 0, i1src
= 0;
1288 /* PATTERN (I2), or a copy of it in certain cases. */
1290 /* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */
1291 int i2dest_in_i2src
= 0, i1dest_in_i1src
= 0, i2dest_in_i1src
= 0;
1292 int i1_feeds_i3
= 0;
1293 /* Notes that must be added to REG_NOTES in I3 and I2. */
1294 rtx new_i3_notes
, new_i2_notes
;
1295 /* Notes that we substituted I3 into I2 instead of the normal case. */
1296 int i3_subst_into_i2
= 0;
1297 /* Notes that I1, I2 or I3 is a MULT operation. */
1299 /* Number of clobbers of SCRATCH we had to add. */
1300 int i3_scratches
= 0, i2_scratches
= 0, other_scratches
= 0;
1307 /* If any of I1, I2, and I3 isn't really an insn, we can't do anything.
1308 This can occur when flow deletes an insn that it has merged into an
1309 auto-increment address. We also can't do anything if I3 has a
1310 REG_LIBCALL note since we don't want to disrupt the contiguity of a
1313 if (GET_RTX_CLASS (GET_CODE (i3
)) != 'i'
1314 || GET_RTX_CLASS (GET_CODE (i2
)) != 'i'
1315 || (i1
&& GET_RTX_CLASS (GET_CODE (i1
)) != 'i')
1316 || find_reg_note (i3
, REG_LIBCALL
, NULL_RTX
))
1321 undobuf
.undos
= undobuf
.previous_undos
= 0;
1322 undobuf
.other_insn
= 0;
1324 /* Save the current high-water-mark so we can free storage if we didn't
1325 accept this combination. */
1326 undobuf
.storage
= (char *) oballoc (0);
1328 /* Reset the hard register usage information. */
1329 CLEAR_HARD_REG_SET (newpat_used_regs
);
1331 /* If I1 and I2 both feed I3, they can be in any order. To simplify the
1332 code below, set I1 to be the earlier of the two insns. */
1333 if (i1
&& INSN_CUID (i1
) > INSN_CUID (i2
))
1334 temp
= i1
, i1
= i2
, i2
= temp
;
1336 added_links_insn
= 0;
1338 /* First check for one important special-case that the code below will
1339 not handle. Namely, the case where I1 is zero, I2 has multiple sets,
1340 and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case,
1341 we may be able to replace that destination with the destination of I3.
1342 This occurs in the common code where we compute both a quotient and
1343 remainder into a structure, in which case we want to do the computation
1344 directly into the structure to avoid register-register copies.
1346 We make very conservative checks below and only try to handle the
1347 most common cases of this. For example, we only handle the case
1348 where I2 and I3 are adjacent to avoid making difficult register
1351 if (i1
== 0 && GET_CODE (i3
) == INSN
&& GET_CODE (PATTERN (i3
)) == SET
1352 && GET_CODE (SET_SRC (PATTERN (i3
))) == REG
1353 && REGNO (SET_SRC (PATTERN (i3
))) >= FIRST_PSEUDO_REGISTER
1354 && (! SMALL_REGISTER_CLASSES
1355 || (GET_CODE (SET_DEST (PATTERN (i3
))) != REG
1356 || REGNO (SET_DEST (PATTERN (i3
))) >= FIRST_PSEUDO_REGISTER
1357 || REG_USERVAR_P (SET_DEST (PATTERN (i3
)))))
1358 && find_reg_note (i3
, REG_DEAD
, SET_SRC (PATTERN (i3
)))
1359 && GET_CODE (PATTERN (i2
)) == PARALLEL
1360 && ! side_effects_p (SET_DEST (PATTERN (i3
)))
1361 /* If the dest of I3 is a ZERO_EXTRACT or STRICT_LOW_PART, the code
1362 below would need to check what is inside (and reg_overlap_mentioned_p
1363 doesn't support those codes anyway). Don't allow those destinations;
1364 the resulting insn isn't likely to be recognized anyway. */
1365 && GET_CODE (SET_DEST (PATTERN (i3
))) != ZERO_EXTRACT
1366 && GET_CODE (SET_DEST (PATTERN (i3
))) != STRICT_LOW_PART
1367 && ! reg_overlap_mentioned_p (SET_SRC (PATTERN (i3
)),
1368 SET_DEST (PATTERN (i3
)))
1369 && next_real_insn (i2
) == i3
)
1371 rtx p2
= PATTERN (i2
);
1373 /* Make sure that the destination of I3,
1374 which we are going to substitute into one output of I2,
1375 is not used within another output of I2. We must avoid making this:
1376 (parallel [(set (mem (reg 69)) ...)
1377 (set (reg 69) ...)])
1378 which is not well-defined as to order of actions.
1379 (Besides, reload can't handle output reloads for this.)
1381 The problem can also happen if the dest of I3 is a memory ref,
1382 if another dest in I2 is an indirect memory ref. */
1383 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
1384 if ((GET_CODE (XVECEXP (p2
, 0, i
)) == SET
1385 || GET_CODE (XVECEXP (p2
, 0, i
)) == CLOBBER
)
1386 && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3
)),
1387 SET_DEST (XVECEXP (p2
, 0, i
))))
1390 if (i
== XVECLEN (p2
, 0))
1391 for (i
= 0; i
< XVECLEN (p2
, 0); i
++)
1392 if (SET_DEST (XVECEXP (p2
, 0, i
)) == SET_SRC (PATTERN (i3
)))
1397 subst_low_cuid
= INSN_CUID (i2
);
1399 added_sets_2
= added_sets_1
= 0;
1400 i2dest
= SET_SRC (PATTERN (i3
));
1402 /* Replace the dest in I2 with our dest and make the resulting
1403 insn the new pattern for I3. Then skip to where we
1404 validate the pattern. Everything was set up above. */
1405 SUBST (SET_DEST (XVECEXP (p2
, 0, i
)),
1406 SET_DEST (PATTERN (i3
)));
1409 i3_subst_into_i2
= 1;
1410 goto validate_replacement
;
1415 /* If we have no I1 and I2 looks like:
1416 (parallel [(set (reg:CC X) (compare:CC OP (const_int 0)))
1418 make up a dummy I1 that is
1421 (set (reg:CC X) (compare:CC Y (const_int 0)))
1423 (We can ignore any trailing CLOBBERs.)
1425 This undoes a previous combination and allows us to match a branch-and-
1428 if (i1
== 0 && GET_CODE (PATTERN (i2
)) == PARALLEL
1429 && XVECLEN (PATTERN (i2
), 0) >= 2
1430 && GET_CODE (XVECEXP (PATTERN (i2
), 0, 0)) == SET
1431 && (GET_MODE_CLASS (GET_MODE (SET_DEST (XVECEXP (PATTERN (i2
), 0, 0))))
1433 && GET_CODE (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0))) == COMPARE
1434 && XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 1) == const0_rtx
1435 && GET_CODE (XVECEXP (PATTERN (i2
), 0, 1)) == SET
1436 && GET_CODE (SET_DEST (XVECEXP (PATTERN (i2
), 0, 1))) == REG
1437 && rtx_equal_p (XEXP (SET_SRC (XVECEXP (PATTERN (i2
), 0, 0)), 0),
1438 SET_SRC (XVECEXP (PATTERN (i2
), 0, 1))))
1440 for (i
= XVECLEN (PATTERN (i2
), 0) - 1; i
>= 2; i
--)
1441 if (GET_CODE (XVECEXP (PATTERN (i2
), 0, i
)) != CLOBBER
)
1446 /* We make I1 with the same INSN_UID as I2. This gives it
1447 the same INSN_CUID for value tracking. Our fake I1 will
1448 never appear in the insn stream so giving it the same INSN_UID
1449 as I2 will not cause a problem. */
1451 subst_prev_insn
= i1
1452 = gen_rtx (INSN
, VOIDmode
, INSN_UID (i2
), NULL_RTX
, i2
,
1453 XVECEXP (PATTERN (i2
), 0, 1), -1, NULL_RTX
, NULL_RTX
);
1455 SUBST (PATTERN (i2
), XVECEXP (PATTERN (i2
), 0, 0));
1456 SUBST (XEXP (SET_SRC (PATTERN (i2
)), 0),
1457 SET_DEST (PATTERN (i1
)));
1462 /* Verify that I2 and I1 are valid for combining. */
1463 if (! can_combine_p (i2
, i3
, i1
, NULL_RTX
, &i2dest
, &i2src
)
1464 || (i1
&& ! can_combine_p (i1
, i3
, NULL_RTX
, i2
, &i1dest
, &i1src
)))
1470 /* Record whether I2DEST is used in I2SRC and similarly for the other
1471 cases. Knowing this will help in register status updating below. */
1472 i2dest_in_i2src
= reg_overlap_mentioned_p (i2dest
, i2src
);
1473 i1dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i1dest
, i1src
);
1474 i2dest_in_i1src
= i1
&& reg_overlap_mentioned_p (i2dest
, i1src
);
1476 /* See if I1 directly feeds into I3. It does if I1DEST is not used
1478 i1_feeds_i3
= i1
&& ! reg_overlap_mentioned_p (i1dest
, i2src
);
1480 /* Ensure that I3's pattern can be the destination of combines. */
1481 if (! combinable_i3pat (i3
, &PATTERN (i3
), i2dest
, i1dest
,
1482 i1
&& i2dest_in_i1src
&& i1_feeds_i3
,
1489 /* See if any of the insns is a MULT operation. Unless one is, we will
1490 reject a combination that is, since it must be slower. Be conservative
1492 if (GET_CODE (i2src
) == MULT
1493 || (i1
!= 0 && GET_CODE (i1src
) == MULT
)
1494 || (GET_CODE (PATTERN (i3
)) == SET
1495 && GET_CODE (SET_SRC (PATTERN (i3
))) == MULT
))
1498 /* If I3 has an inc, then give up if I1 or I2 uses the reg that is inc'd.
1499 We used to do this EXCEPT in one case: I3 has a post-inc in an
1500 output operand. However, that exception can give rise to insns like
1502 which is a famous insn on the PDP-11 where the value of r3 used as the
1503 source was model-dependent. Avoid this sort of thing. */
1506 if (!(GET_CODE (PATTERN (i3
)) == SET
1507 && GET_CODE (SET_SRC (PATTERN (i3
))) == REG
1508 && GET_CODE (SET_DEST (PATTERN (i3
))) == MEM
1509 && (GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_INC
1510 || GET_CODE (XEXP (SET_DEST (PATTERN (i3
)), 0)) == POST_DEC
)))
1511 /* It's not the exception. */
1514 for (link
= REG_NOTES (i3
); link
; link
= XEXP (link
, 1))
1515 if (REG_NOTE_KIND (link
) == REG_INC
1516 && (reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i2
))
1518 && reg_overlap_mentioned_p (XEXP (link
, 0), PATTERN (i1
)))))
1525 /* See if the SETs in I1 or I2 need to be kept around in the merged
1526 instruction: whenever the value set there is still needed past I3.
1527 For the SETs in I2, this is easy: we see if I2DEST dies or is set in I3.
1529 For the SET in I1, we have two cases: If I1 and I2 independently
1530 feed into I3, the set in I1 needs to be kept around if I1DEST dies
1531 or is set in I3. Otherwise (if I1 feeds I2 which feeds I3), the set
1532 in I1 needs to be kept around unless I1DEST dies or is set in either
1533 I2 or I3. We can distinguish these cases by seeing if I2SRC mentions
1534 I1DEST. If so, we know I1 feeds into I2. */
1536 added_sets_2
= ! dead_or_set_p (i3
, i2dest
);
1539 = i1
&& ! (i1_feeds_i3
? dead_or_set_p (i3
, i1dest
)
1540 : (dead_or_set_p (i3
, i1dest
) || dead_or_set_p (i2
, i1dest
)));
1542 /* If the set in I2 needs to be kept around, we must make a copy of
1543 PATTERN (I2), so that when we substitute I1SRC for I1DEST in
1544 PATTERN (I2), we are only substituting for the original I1DEST, not into
1545 an already-substituted copy. This also prevents making self-referential
1546 rtx. If I2 is a PARALLEL, we just need the piece that assigns I2SRC to
1549 i2pat
= (GET_CODE (PATTERN (i2
)) == PARALLEL
1550 ? gen_rtx (SET
, VOIDmode
, i2dest
, i2src
)
1554 i2pat
= copy_rtx (i2pat
);
1558 /* Substitute in the latest insn for the regs set by the earlier ones. */
1560 maxreg
= max_reg_num ();
1564 /* It is possible that the source of I2 or I1 may be performing an
1565 unneeded operation, such as a ZERO_EXTEND of something that is known
1566 to have the high part zero. Handle that case by letting subst look at
1567 the innermost one of them.
1569 Another way to do this would be to have a function that tries to
1570 simplify a single insn instead of merging two or more insns. We don't
1571 do this because of the potential of infinite loops and because
1572 of the potential extra memory required. However, doing it the way
1573 we are is a bit of a kludge and doesn't catch all cases.
1575 But only do this if -fexpensive-optimizations since it slows things down
1576 and doesn't usually win. */
1578 if (flag_expensive_optimizations
)
1580 /* Pass pc_rtx so no substitutions are done, just simplifications.
1581 The cases that we are interested in here do not involve the few
1582 cases were is_replaced is checked. */
1585 subst_low_cuid
= INSN_CUID (i1
);
1586 i1src
= subst (i1src
, pc_rtx
, pc_rtx
, 0, 0);
1590 subst_low_cuid
= INSN_CUID (i2
);
1591 i2src
= subst (i2src
, pc_rtx
, pc_rtx
, 0, 0);
1594 undobuf
.previous_undos
= undobuf
.undos
;
1598 /* Many machines that don't use CC0 have insns that can both perform an
1599 arithmetic operation and set the condition code. These operations will
1600 be represented as a PARALLEL with the first element of the vector
1601 being a COMPARE of an arithmetic operation with the constant zero.
1602 The second element of the vector will set some pseudo to the result
1603 of the same arithmetic operation. If we simplify the COMPARE, we won't
1604 match such a pattern and so will generate an extra insn. Here we test
1605 for this case, where both the comparison and the operation result are
1606 needed, and make the PARALLEL by just replacing I2DEST in I3SRC with
1607 I2SRC. Later we will make the PARALLEL that contains I2. */
1609 if (i1
== 0 && added_sets_2
&& GET_CODE (PATTERN (i3
)) == SET
1610 && GET_CODE (SET_SRC (PATTERN (i3
))) == COMPARE
1611 && XEXP (SET_SRC (PATTERN (i3
)), 1) == const0_rtx
1612 && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3
)), 0), i2dest
))
1615 enum machine_mode compare_mode
;
1617 newpat
= PATTERN (i3
);
1618 SUBST (XEXP (SET_SRC (newpat
), 0), i2src
);
1622 #ifdef EXTRA_CC_MODES
1623 /* See if a COMPARE with the operand we substituted in should be done
1624 with the mode that is currently being used. If not, do the same
1625 processing we do in `subst' for a SET; namely, if the destination
1626 is used only once, try to replace it with a register of the proper
1627 mode and also replace the COMPARE. */
1628 if (undobuf
.other_insn
== 0
1629 && (cc_use
= find_single_use (SET_DEST (newpat
), i3
,
1630 &undobuf
.other_insn
))
1631 && ((compare_mode
= SELECT_CC_MODE (GET_CODE (*cc_use
),
1633 != GET_MODE (SET_DEST (newpat
))))
1635 int regno
= REGNO (SET_DEST (newpat
));
1636 rtx new_dest
= gen_rtx (REG
, compare_mode
, regno
);
1638 if (regno
< FIRST_PSEUDO_REGISTER
1639 || (REG_N_SETS (regno
) == 1 && ! added_sets_2
1640 && ! REG_USERVAR_P (SET_DEST (newpat
))))
1642 if (regno
>= FIRST_PSEUDO_REGISTER
)
1643 SUBST (regno_reg_rtx
[regno
], new_dest
);
1645 SUBST (SET_DEST (newpat
), new_dest
);
1646 SUBST (XEXP (*cc_use
, 0), new_dest
);
1647 SUBST (SET_SRC (newpat
),
1648 gen_rtx_combine (COMPARE
, compare_mode
,
1649 i2src
, const0_rtx
));
1652 undobuf
.other_insn
= 0;
1659 n_occurrences
= 0; /* `subst' counts here */
1661 /* If I1 feeds into I2 (not into I3) and I1DEST is in I1SRC, we
1662 need to make a unique copy of I2SRC each time we substitute it
1663 to avoid self-referential rtl. */
1665 subst_low_cuid
= INSN_CUID (i2
);
1666 newpat
= subst (PATTERN (i3
), i2dest
, i2src
, 0,
1667 ! i1_feeds_i3
&& i1dest_in_i1src
);
1668 undobuf
.previous_undos
= undobuf
.undos
;
1670 /* Record whether i2's body now appears within i3's body. */
1671 i2_is_used
= n_occurrences
;
1674 /* If we already got a failure, don't try to do more. Otherwise,
1675 try to substitute in I1 if we have it. */
1677 if (i1
&& GET_CODE (newpat
) != CLOBBER
)
1679 /* Before we can do this substitution, we must redo the test done
1680 above (see detailed comments there) that ensures that I1DEST
1681 isn't mentioned in any SETs in NEWPAT that are field assignments. */
1683 if (! combinable_i3pat (NULL_RTX
, &newpat
, i1dest
, NULL_RTX
,
1691 subst_low_cuid
= INSN_CUID (i1
);
1692 newpat
= subst (newpat
, i1dest
, i1src
, 0, 0);
1693 undobuf
.previous_undos
= undobuf
.undos
;
1696 /* Fail if an autoincrement side-effect has been duplicated. Be careful
1697 to count all the ways that I2SRC and I1SRC can be used. */
1698 if ((FIND_REG_INC_NOTE (i2
, NULL_RTX
) != 0
1699 && i2_is_used
+ added_sets_2
> 1)
1700 || (i1
!= 0 && FIND_REG_INC_NOTE (i1
, NULL_RTX
) != 0
1701 && (n_occurrences
+ added_sets_1
+ (added_sets_2
&& ! i1_feeds_i3
)
1703 /* Fail if we tried to make a new register (we used to abort, but there's
1704 really no reason to). */
1705 || max_reg_num () != maxreg
1706 /* Fail if we couldn't do something and have a CLOBBER. */
1707 || GET_CODE (newpat
) == CLOBBER
1708 /* Fail if this new pattern is a MULT and we didn't have one before
1709 at the outer level. */
1710 || (GET_CODE (newpat
) == SET
&& GET_CODE (SET_SRC (newpat
)) == MULT
1717 /* If the actions of the earlier insns must be kept
1718 in addition to substituting them into the latest one,
1719 we must make a new PARALLEL for the latest insn
1720 to hold additional the SETs. */
1722 if (added_sets_1
|| added_sets_2
)
1726 if (GET_CODE (newpat
) == PARALLEL
)
1728 rtvec old
= XVEC (newpat
, 0);
1729 total_sets
= XVECLEN (newpat
, 0) + added_sets_1
+ added_sets_2
;
1730 newpat
= gen_rtx (PARALLEL
, VOIDmode
, rtvec_alloc (total_sets
));
1731 bcopy ((char *) &old
->elem
[0], (char *) XVEC (newpat
, 0)->elem
,
1732 sizeof (old
->elem
[0]) * old
->num_elem
);
1737 total_sets
= 1 + added_sets_1
+ added_sets_2
;
1738 newpat
= gen_rtx (PARALLEL
, VOIDmode
, rtvec_alloc (total_sets
));
1739 XVECEXP (newpat
, 0, 0) = old
;
1743 XVECEXP (newpat
, 0, --total_sets
)
1744 = (GET_CODE (PATTERN (i1
)) == PARALLEL
1745 ? gen_rtx (SET
, VOIDmode
, i1dest
, i1src
) : PATTERN (i1
));
1749 /* If there is no I1, use I2's body as is. We used to also not do
1750 the subst call below if I2 was substituted into I3,
1751 but that could lose a simplification. */
1753 XVECEXP (newpat
, 0, --total_sets
) = i2pat
;
1755 /* See comment where i2pat is assigned. */
1756 XVECEXP (newpat
, 0, --total_sets
)
1757 = subst (i2pat
, i1dest
, i1src
, 0, 0);
1761 /* We come here when we are replacing a destination in I2 with the
1762 destination of I3. */
1763 validate_replacement
:
1765 /* Note which hard regs this insn has as inputs. */
1766 mark_used_regs_combine (newpat
);
1768 /* Is the result of combination a valid instruction? */
1770 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
1772 /* If the result isn't valid, see if it is a PARALLEL of two SETs where
1773 the second SET's destination is a register that is unused. In that case,
1774 we just need the first SET. This can occur when simplifying a divmod
1775 insn. We *must* test for this case here because the code below that
1776 splits two independent SETs doesn't handle this case correctly when it
1777 updates the register status. Also check the case where the first
1778 SET's destination is unused. That would not cause incorrect code, but
1779 does cause an unneeded insn to remain. */
1781 if (insn_code_number
< 0 && GET_CODE (newpat
) == PARALLEL
1782 && XVECLEN (newpat
, 0) == 2
1783 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
1784 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
1785 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) == REG
1786 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (XVECEXP (newpat
, 0, 1)))
1787 && ! side_effects_p (SET_SRC (XVECEXP (newpat
, 0, 1)))
1788 && asm_noperands (newpat
) < 0)
1790 newpat
= XVECEXP (newpat
, 0, 0);
1792 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
1795 else if (insn_code_number
< 0 && GET_CODE (newpat
) == PARALLEL
1796 && XVECLEN (newpat
, 0) == 2
1797 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
1798 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
1799 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) == REG
1800 && find_reg_note (i3
, REG_UNUSED
, SET_DEST (XVECEXP (newpat
, 0, 0)))
1801 && ! side_effects_p (SET_SRC (XVECEXP (newpat
, 0, 0)))
1802 && asm_noperands (newpat
) < 0)
1804 newpat
= XVECEXP (newpat
, 0, 1);
1806 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
1809 /* If we were combining three insns and the result is a simple SET
1810 with no ASM_OPERANDS that wasn't recognized, try to split it into two
1811 insns. There are two ways to do this. It can be split using a
1812 machine-specific method (like when you have an addition of a large
1813 constant) or by combine in the function find_split_point. */
1815 if (i1
&& insn_code_number
< 0 && GET_CODE (newpat
) == SET
1816 && asm_noperands (newpat
) < 0)
1818 rtx m_split
, *split
;
1819 rtx ni2dest
= i2dest
;
1821 /* See if the MD file can split NEWPAT. If it can't, see if letting it
1822 use I2DEST as a scratch register will help. In the latter case,
1823 convert I2DEST to the mode of the source of NEWPAT if we can. */
1825 m_split
= split_insns (newpat
, i3
);
1827 /* We can only use I2DEST as a scratch reg if it doesn't overlap any
1828 inputs of NEWPAT. */
1830 /* ??? If I2DEST is not safe, and I1DEST exists, then it would be
1831 possible to try that as a scratch reg. This would require adding
1832 more code to make it work though. */
1834 if (m_split
== 0 && ! reg_overlap_mentioned_p (ni2dest
, newpat
))
1836 /* If I2DEST is a hard register or the only use of a pseudo,
1837 we can change its mode. */
1838 if (GET_MODE (SET_DEST (newpat
)) != GET_MODE (i2dest
)
1839 && GET_MODE (SET_DEST (newpat
)) != VOIDmode
1840 && GET_CODE (i2dest
) == REG
1841 && (REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
1842 || (REG_N_SETS (REGNO (i2dest
)) == 1 && ! added_sets_2
1843 && ! REG_USERVAR_P (i2dest
))))
1844 ni2dest
= gen_rtx (REG
, GET_MODE (SET_DEST (newpat
)),
1847 m_split
= split_insns (gen_rtx (PARALLEL
, VOIDmode
,
1848 gen_rtvec (2, newpat
,
1855 if (m_split
&& GET_CODE (m_split
) == SEQUENCE
1856 && XVECLEN (m_split
, 0) == 2
1857 && (next_real_insn (i2
) == i3
1858 || ! use_crosses_set_p (PATTERN (XVECEXP (m_split
, 0, 0)),
1862 rtx newi3pat
= PATTERN (XVECEXP (m_split
, 0, 1));
1863 newi2pat
= PATTERN (XVECEXP (m_split
, 0, 0));
1865 i3set
= single_set (XVECEXP (m_split
, 0, 1));
1866 i2set
= single_set (XVECEXP (m_split
, 0, 0));
1868 /* In case we changed the mode of I2DEST, replace it in the
1869 pseudo-register table here. We can't do it above in case this
1870 code doesn't get executed and we do a split the other way. */
1872 if (REGNO (i2dest
) >= FIRST_PSEUDO_REGISTER
)
1873 SUBST (regno_reg_rtx
[REGNO (i2dest
)], ni2dest
);
1875 i2_code_number
= recog_for_combine (&newi2pat
, i2
, &new_i2_notes
,
1878 /* If I2 or I3 has multiple SETs, we won't know how to track
1879 register status, so don't use these insns. If I2's destination
1880 is used between I2 and I3, we also can't use these insns. */
1882 if (i2_code_number
>= 0 && i2set
&& i3set
1883 && (next_real_insn (i2
) == i3
1884 || ! reg_used_between_p (SET_DEST (i2set
), i2
, i3
)))
1885 insn_code_number
= recog_for_combine (&newi3pat
, i3
, &new_i3_notes
,
1887 if (insn_code_number
>= 0)
1890 /* It is possible that both insns now set the destination of I3.
1891 If so, we must show an extra use of it. */
1893 if (insn_code_number
>= 0)
1895 rtx new_i3_dest
= SET_DEST (i3set
);
1896 rtx new_i2_dest
= SET_DEST (i2set
);
1898 while (GET_CODE (new_i3_dest
) == ZERO_EXTRACT
1899 || GET_CODE (new_i3_dest
) == STRICT_LOW_PART
1900 || GET_CODE (new_i3_dest
) == SUBREG
)
1901 new_i3_dest
= XEXP (new_i3_dest
, 0);
1903 while (GET_CODE (new_i2_dest
) == ZERO_EXTRACT
1904 || GET_CODE (new_i2_dest
) == STRICT_LOW_PART
1905 || GET_CODE (new_i2_dest
) == SUBREG
)
1906 new_i2_dest
= XEXP (new_i2_dest
, 0);
1908 if (GET_CODE (new_i3_dest
) == REG
1909 && GET_CODE (new_i2_dest
) == REG
1910 && REGNO (new_i3_dest
) == REGNO (new_i2_dest
))
1911 REG_N_SETS (REGNO (new_i2_dest
))++;
1915 /* If we can split it and use I2DEST, go ahead and see if that
1916 helps things be recognized. Verify that none of the registers
1917 are set between I2 and I3. */
1918 if (insn_code_number
< 0 && (split
= find_split_point (&newpat
, i3
)) != 0
1920 && GET_CODE (i2dest
) == REG
1922 /* We need I2DEST in the proper mode. If it is a hard register
1923 or the only use of a pseudo, we can change its mode. */
1924 && (GET_MODE (*split
) == GET_MODE (i2dest
)
1925 || GET_MODE (*split
) == VOIDmode
1926 || REGNO (i2dest
) < FIRST_PSEUDO_REGISTER
1927 || (REG_N_SETS (REGNO (i2dest
)) == 1 && ! added_sets_2
1928 && ! REG_USERVAR_P (i2dest
)))
1929 && (next_real_insn (i2
) == i3
1930 || ! use_crosses_set_p (*split
, INSN_CUID (i2
)))
1931 /* We can't overwrite I2DEST if its value is still used by
1933 && ! reg_referenced_p (i2dest
, newpat
))
1935 rtx newdest
= i2dest
;
1936 enum rtx_code split_code
= GET_CODE (*split
);
1937 enum machine_mode split_mode
= GET_MODE (*split
);
1939 /* Get NEWDEST as a register in the proper mode. We have already
1940 validated that we can do this. */
1941 if (GET_MODE (i2dest
) != split_mode
&& split_mode
!= VOIDmode
)
1943 newdest
= gen_rtx (REG
, split_mode
, REGNO (i2dest
));
1945 if (REGNO (i2dest
) >= FIRST_PSEUDO_REGISTER
)
1946 SUBST (regno_reg_rtx
[REGNO (i2dest
)], newdest
);
1949 /* If *SPLIT is a (mult FOO (const_int pow2)), convert it to
1950 an ASHIFT. This can occur if it was inside a PLUS and hence
1951 appeared to be a memory address. This is a kludge. */
1952 if (split_code
== MULT
1953 && GET_CODE (XEXP (*split
, 1)) == CONST_INT
1954 && (i
= exact_log2 (INTVAL (XEXP (*split
, 1)))) >= 0)
1956 SUBST (*split
, gen_rtx_combine (ASHIFT
, split_mode
,
1957 XEXP (*split
, 0), GEN_INT (i
)));
1958 /* Update split_code because we may not have a multiply
1960 split_code
= GET_CODE (*split
);
1963 #ifdef INSN_SCHEDULING
1964 /* If *SPLIT is a paradoxical SUBREG, when we split it, it should
1965 be written as a ZERO_EXTEND. */
1966 if (split_code
== SUBREG
&& GET_CODE (SUBREG_REG (*split
)) == MEM
)
1967 SUBST (*split
, gen_rtx_combine (ZERO_EXTEND
, split_mode
,
1971 newi2pat
= gen_rtx_combine (SET
, VOIDmode
, newdest
, *split
);
1972 SUBST (*split
, newdest
);
1974 = recog_for_combine (&newi2pat
, i2
, &new_i2_notes
, &i2_scratches
);
1976 /* If the split point was a MULT and we didn't have one before,
1977 don't use one now. */
1978 if (i2_code_number
>= 0 && ! (split_code
== MULT
&& ! have_mult
))
1980 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
1984 /* Check for a case where we loaded from memory in a narrow mode and
1985 then sign extended it, but we need both registers. In that case,
1986 we have a PARALLEL with both loads from the same memory location.
1987 We can split this into a load from memory followed by a register-register
1988 copy. This saves at least one insn, more if register allocation can
1991 We cannot do this if the destination of the second assignment is
1992 a register that we have already assumed is zero-extended. Similarly
1993 for a SUBREG of such a register. */
1995 else if (i1
&& insn_code_number
< 0 && asm_noperands (newpat
) < 0
1996 && GET_CODE (newpat
) == PARALLEL
1997 && XVECLEN (newpat
, 0) == 2
1998 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
1999 && GET_CODE (SET_SRC (XVECEXP (newpat
, 0, 0))) == SIGN_EXTEND
2000 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
2001 && rtx_equal_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
2002 XEXP (SET_SRC (XVECEXP (newpat
, 0, 0)), 0))
2003 && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
2005 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
2006 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
2007 && ! (temp
= SET_DEST (XVECEXP (newpat
, 0, 1)),
2008 (GET_CODE (temp
) == REG
2009 && reg_nonzero_bits
[REGNO (temp
)] != 0
2010 && GET_MODE_BITSIZE (GET_MODE (temp
)) < BITS_PER_WORD
2011 && GET_MODE_BITSIZE (GET_MODE (temp
)) < HOST_BITS_PER_INT
2012 && (reg_nonzero_bits
[REGNO (temp
)]
2013 != GET_MODE_MASK (word_mode
))))
2014 && ! (GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) == SUBREG
2015 && (temp
= SUBREG_REG (SET_DEST (XVECEXP (newpat
, 0, 1))),
2016 (GET_CODE (temp
) == REG
2017 && reg_nonzero_bits
[REGNO (temp
)] != 0
2018 && GET_MODE_BITSIZE (GET_MODE (temp
)) < BITS_PER_WORD
2019 && GET_MODE_BITSIZE (GET_MODE (temp
)) < HOST_BITS_PER_INT
2020 && (reg_nonzero_bits
[REGNO (temp
)]
2021 != GET_MODE_MASK (word_mode
)))))
2022 && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
2023 SET_SRC (XVECEXP (newpat
, 0, 1)))
2024 && ! find_reg_note (i3
, REG_UNUSED
,
2025 SET_DEST (XVECEXP (newpat
, 0, 0))))
2029 newi2pat
= XVECEXP (newpat
, 0, 0);
2030 ni2dest
= SET_DEST (XVECEXP (newpat
, 0, 0));
2031 newpat
= XVECEXP (newpat
, 0, 1);
2032 SUBST (SET_SRC (newpat
),
2033 gen_lowpart_for_combine (GET_MODE (SET_SRC (newpat
)), ni2dest
));
2035 = recog_for_combine (&newi2pat
, i2
, &new_i2_notes
, &i2_scratches
);
2037 if (i2_code_number
>= 0)
2039 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
2041 if (insn_code_number
>= 0)
2046 /* If we will be able to accept this, we have made a change to the
2047 destination of I3. This can invalidate a LOG_LINKS pointing
2048 to I3. No other part of combine.c makes such a transformation.
2050 The new I3 will have a destination that was previously the
2051 destination of I1 or I2 and which was used in i2 or I3. Call
2052 distribute_links to make a LOG_LINK from the next use of
2053 that destination. */
2055 PATTERN (i3
) = newpat
;
2056 distribute_links (gen_rtx (INSN_LIST
, VOIDmode
, i3
, NULL_RTX
));
2058 /* I3 now uses what used to be its destination and which is
2059 now I2's destination. That means we need a LOG_LINK from
2060 I3 to I2. But we used to have one, so we still will.
2062 However, some later insn might be using I2's dest and have
2063 a LOG_LINK pointing at I3. We must remove this link.
2064 The simplest way to remove the link is to point it at I1,
2065 which we know will be a NOTE. */
2067 for (insn
= NEXT_INSN (i3
);
2068 insn
&& (this_basic_block
== n_basic_blocks
- 1
2069 || insn
!= basic_block_head
[this_basic_block
+ 1]);
2070 insn
= NEXT_INSN (insn
))
2072 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
2073 && reg_referenced_p (ni2dest
, PATTERN (insn
)))
2075 for (link
= LOG_LINKS (insn
); link
;
2076 link
= XEXP (link
, 1))
2077 if (XEXP (link
, 0) == i3
)
2078 XEXP (link
, 0) = i1
;
2086 /* Similarly, check for a case where we have a PARALLEL of two independent
2087 SETs but we started with three insns. In this case, we can do the sets
2088 as two separate insns. This case occurs when some SET allows two
2089 other insns to combine, but the destination of that SET is still live. */
2091 else if (i1
&& insn_code_number
< 0 && asm_noperands (newpat
) < 0
2092 && GET_CODE (newpat
) == PARALLEL
2093 && XVECLEN (newpat
, 0) == 2
2094 && GET_CODE (XVECEXP (newpat
, 0, 0)) == SET
2095 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != ZERO_EXTRACT
2096 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != STRICT_LOW_PART
2097 && GET_CODE (XVECEXP (newpat
, 0, 1)) == SET
2098 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != ZERO_EXTRACT
2099 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != STRICT_LOW_PART
2100 && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat
, 0, 1)),
2102 /* Don't pass sets with (USE (MEM ...)) dests to the following. */
2103 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 1))) != USE
2104 && GET_CODE (SET_DEST (XVECEXP (newpat
, 0, 0))) != USE
2105 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 1)),
2106 XVECEXP (newpat
, 0, 0))
2107 && ! reg_referenced_p (SET_DEST (XVECEXP (newpat
, 0, 0)),
2108 XVECEXP (newpat
, 0, 1)))
2110 /* Normally, it doesn't matter which of the two is done first,
2111 but it does if one references cc0. In that case, it has to
2114 if (reg_referenced_p (cc0_rtx
, XVECEXP (newpat
, 0, 0)))
2116 newi2pat
= XVECEXP (newpat
, 0, 0);
2117 newpat
= XVECEXP (newpat
, 0, 1);
2122 newi2pat
= XVECEXP (newpat
, 0, 1);
2123 newpat
= XVECEXP (newpat
, 0, 0);
2127 = recog_for_combine (&newi2pat
, i2
, &new_i2_notes
, &i2_scratches
);
2129 if (i2_code_number
>= 0)
2131 = recog_for_combine (&newpat
, i3
, &new_i3_notes
, &i3_scratches
);
2134 /* If it still isn't recognized, fail and change things back the way they
2136 if ((insn_code_number
< 0
2137 /* Is the result a reasonable ASM_OPERANDS? */
2138 && (! check_asm_operands (newpat
) || added_sets_1
|| added_sets_2
)))
2144 /* If we had to change another insn, make sure it is valid also. */
2145 if (undobuf
.other_insn
)
2147 rtx other_pat
= PATTERN (undobuf
.other_insn
);
2148 rtx new_other_notes
;
2151 CLEAR_HARD_REG_SET (newpat_used_regs
);
2154 = recog_for_combine (&other_pat
, undobuf
.other_insn
,
2155 &new_other_notes
, &other_scratches
);
2157 if (other_code_number
< 0 && ! check_asm_operands (other_pat
))
2163 PATTERN (undobuf
.other_insn
) = other_pat
;
2165 /* If any of the notes in OTHER_INSN were REG_UNUSED, ensure that they
2166 are still valid. Then add any non-duplicate notes added by
2167 recog_for_combine. */
2168 for (note
= REG_NOTES (undobuf
.other_insn
); note
; note
= next
)
2170 next
= XEXP (note
, 1);
2172 if (REG_NOTE_KIND (note
) == REG_UNUSED
2173 && ! reg_set_p (XEXP (note
, 0), PATTERN (undobuf
.other_insn
)))
2175 if (GET_CODE (XEXP (note
, 0)) == REG
)
2176 REG_N_DEATHS (REGNO (XEXP (note
, 0)))--;
2178 remove_note (undobuf
.other_insn
, note
);
2182 for (note
= new_other_notes
; note
; note
= XEXP (note
, 1))
2183 if (GET_CODE (XEXP (note
, 0)) == REG
)
2184 REG_N_DEATHS (REGNO (XEXP (note
, 0)))++;
2186 distribute_notes (new_other_notes
, undobuf
.other_insn
,
2187 undobuf
.other_insn
, NULL_RTX
, NULL_RTX
, NULL_RTX
);
2190 /* We now know that we can do this combination. Merge the insns and
2191 update the status of registers and LOG_LINKS. */
2194 rtx i3notes
, i2notes
, i1notes
= 0;
2195 rtx i3links
, i2links
, i1links
= 0;
2198 /* Compute which registers we expect to eliminate. newi2pat may be setting
2199 either i3dest or i2dest, so we must check it. Also, i1dest may be the
2200 same as i3dest, in which case newi2pat may be setting i1dest. */
2201 rtx elim_i2
= ((newi2pat
&& reg_set_p (i2dest
, newi2pat
))
2202 || i2dest_in_i2src
|| i2dest_in_i1src
2204 rtx elim_i1
= (i1
== 0 || i1dest_in_i1src
2205 || (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
2208 /* Get the old REG_NOTES and LOG_LINKS from all our insns and
2210 i3notes
= REG_NOTES (i3
), i3links
= LOG_LINKS (i3
);
2211 i2notes
= REG_NOTES (i2
), i2links
= LOG_LINKS (i2
);
2213 i1notes
= REG_NOTES (i1
), i1links
= LOG_LINKS (i1
);
2215 /* Ensure that we do not have something that should not be shared but
2216 occurs multiple times in the new insns. Check this by first
2217 resetting all the `used' flags and then copying anything is shared. */
2219 reset_used_flags (i3notes
);
2220 reset_used_flags (i2notes
);
2221 reset_used_flags (i1notes
);
2222 reset_used_flags (newpat
);
2223 reset_used_flags (newi2pat
);
2224 if (undobuf
.other_insn
)
2225 reset_used_flags (PATTERN (undobuf
.other_insn
));
2227 i3notes
= copy_rtx_if_shared (i3notes
);
2228 i2notes
= copy_rtx_if_shared (i2notes
);
2229 i1notes
= copy_rtx_if_shared (i1notes
);
2230 newpat
= copy_rtx_if_shared (newpat
);
2231 newi2pat
= copy_rtx_if_shared (newi2pat
);
2232 if (undobuf
.other_insn
)
2233 reset_used_flags (PATTERN (undobuf
.other_insn
));
2235 INSN_CODE (i3
) = insn_code_number
;
2236 PATTERN (i3
) = newpat
;
2237 if (undobuf
.other_insn
)
2238 INSN_CODE (undobuf
.other_insn
) = other_code_number
;
2240 /* We had one special case above where I2 had more than one set and
2241 we replaced a destination of one of those sets with the destination
2242 of I3. In that case, we have to update LOG_LINKS of insns later
2243 in this basic block. Note that this (expensive) case is rare.
2245 Also, in this case, we must pretend that all REG_NOTEs for I2
2246 actually came from I3, so that REG_UNUSED notes from I2 will be
2247 properly handled. */
2249 if (i3_subst_into_i2
)
2251 for (i
= 0; i
< XVECLEN (PATTERN (i2
), 0); i
++)
2252 if (GET_CODE (SET_DEST (XVECEXP (PATTERN (i2
), 0, i
))) == REG
2253 && SET_DEST (XVECEXP (PATTERN (i2
), 0, i
)) != i2dest
2254 && ! find_reg_note (i2
, REG_UNUSED
,
2255 SET_DEST (XVECEXP (PATTERN (i2
), 0, i
))))
2256 for (temp
= NEXT_INSN (i2
);
2257 temp
&& (this_basic_block
== n_basic_blocks
- 1
2258 || basic_block_head
[this_basic_block
] != temp
);
2259 temp
= NEXT_INSN (temp
))
2260 if (temp
!= i3
&& GET_RTX_CLASS (GET_CODE (temp
)) == 'i')
2261 for (link
= LOG_LINKS (temp
); link
; link
= XEXP (link
, 1))
2262 if (XEXP (link
, 0) == i2
)
2263 XEXP (link
, 0) = i3
;
2268 while (XEXP (link
, 1))
2269 link
= XEXP (link
, 1);
2270 XEXP (link
, 1) = i2notes
;
2284 INSN_CODE (i2
) = i2_code_number
;
2285 PATTERN (i2
) = newi2pat
;
2289 PUT_CODE (i2
, NOTE
);
2290 NOTE_LINE_NUMBER (i2
) = NOTE_INSN_DELETED
;
2291 NOTE_SOURCE_FILE (i2
) = 0;
2298 PUT_CODE (i1
, NOTE
);
2299 NOTE_LINE_NUMBER (i1
) = NOTE_INSN_DELETED
;
2300 NOTE_SOURCE_FILE (i1
) = 0;
2303 /* Get death notes for everything that is now used in either I3 or
2304 I2 and used to die in a previous insn. If we built two new
2305 patterns, move from I1 to I2 then I2 to I3 so that we get the
2306 proper movement on registers that I2 modifies. */
2310 move_deaths (newi2pat
, NULL_RTX
, INSN_CUID (i1
), i2
, &midnotes
);
2311 move_deaths (newpat
, newi2pat
, INSN_CUID (i1
), i3
, &midnotes
);
2314 move_deaths (newpat
, NULL_RTX
, i1
? INSN_CUID (i1
) : INSN_CUID (i2
),
2317 /* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */
2319 distribute_notes (i3notes
, i3
, i3
, newi2pat
? i2
: NULL_RTX
,
2322 distribute_notes (i2notes
, i2
, i3
, newi2pat
? i2
: NULL_RTX
,
2325 distribute_notes (i1notes
, i1
, i3
, newi2pat
? i2
: NULL_RTX
,
2328 distribute_notes (midnotes
, NULL_RTX
, i3
, newi2pat
? i2
: NULL_RTX
,
2331 /* Distribute any notes added to I2 or I3 by recog_for_combine. We
2332 know these are REG_UNUSED and want them to go to the desired insn,
2333 so we always pass it as i3. We have not counted the notes in
2334 reg_n_deaths yet, so we need to do so now. */
2336 if (newi2pat
&& new_i2_notes
)
2338 for (temp
= new_i2_notes
; temp
; temp
= XEXP (temp
, 1))
2339 if (GET_CODE (XEXP (temp
, 0)) == REG
)
2340 REG_N_DEATHS (REGNO (XEXP (temp
, 0)))++;
2342 distribute_notes (new_i2_notes
, i2
, i2
, NULL_RTX
, NULL_RTX
, NULL_RTX
);
2347 for (temp
= new_i3_notes
; temp
; temp
= XEXP (temp
, 1))
2348 if (GET_CODE (XEXP (temp
, 0)) == REG
)
2349 REG_N_DEATHS (REGNO (XEXP (temp
, 0)))++;
2351 distribute_notes (new_i3_notes
, i3
, i3
, NULL_RTX
, NULL_RTX
, NULL_RTX
);
2354 /* If I3DEST was used in I3SRC, it really died in I3. We may need to
2355 put a REG_DEAD note for it somewhere. If NEWI2PAT exists and sets
2356 I3DEST, the death must be somewhere before I2, not I3. If we passed I3
2357 in that case, it might delete I2. Similarly for I2 and I1.
2358 Show an additional death due to the REG_DEAD note we make here. If
2359 we discard it in distribute_notes, we will decrement it again. */
2363 if (GET_CODE (i3dest_killed
) == REG
)
2364 REG_N_DEATHS (REGNO (i3dest_killed
))++;
2366 if (newi2pat
&& reg_set_p (i3dest_killed
, newi2pat
))
2367 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i3dest_killed
,
2369 NULL_RTX
, i2
, NULL_RTX
, elim_i2
, elim_i1
);
2371 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i3dest_killed
,
2373 NULL_RTX
, i3
, newi2pat
? i2
: NULL_RTX
,
2377 if (i2dest_in_i2src
)
2379 if (GET_CODE (i2dest
) == REG
)
2380 REG_N_DEATHS (REGNO (i2dest
))++;
2382 if (newi2pat
&& reg_set_p (i2dest
, newi2pat
))
2383 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i2dest
, NULL_RTX
),
2384 NULL_RTX
, i2
, NULL_RTX
, NULL_RTX
, NULL_RTX
);
2386 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i2dest
, NULL_RTX
),
2387 NULL_RTX
, i3
, newi2pat
? i2
: NULL_RTX
,
2388 NULL_RTX
, NULL_RTX
);
2391 if (i1dest_in_i1src
)
2393 if (GET_CODE (i1dest
) == REG
)
2394 REG_N_DEATHS (REGNO (i1dest
))++;
2396 if (newi2pat
&& reg_set_p (i1dest
, newi2pat
))
2397 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i1dest
, NULL_RTX
),
2398 NULL_RTX
, i2
, NULL_RTX
, NULL_RTX
, NULL_RTX
);
2400 distribute_notes (gen_rtx (EXPR_LIST
, REG_DEAD
, i1dest
, NULL_RTX
),
2401 NULL_RTX
, i3
, newi2pat
? i2
: NULL_RTX
,
2402 NULL_RTX
, NULL_RTX
);
2405 distribute_links (i3links
);
2406 distribute_links (i2links
);
2407 distribute_links (i1links
);
2409 if (GET_CODE (i2dest
) == REG
)
2412 rtx i2_insn
= 0, i2_val
= 0, set
;
2414 /* The insn that used to set this register doesn't exist, and
2415 this life of the register may not exist either. See if one of
2416 I3's links points to an insn that sets I2DEST. If it does,
2417 that is now the last known value for I2DEST. If we don't update
2418 this and I2 set the register to a value that depended on its old
2419 contents, we will get confused. If this insn is used, thing
2420 will be set correctly in combine_instructions. */
2422 for (link
= LOG_LINKS (i3
); link
; link
= XEXP (link
, 1))
2423 if ((set
= single_set (XEXP (link
, 0))) != 0
2424 && rtx_equal_p (i2dest
, SET_DEST (set
)))
2425 i2_insn
= XEXP (link
, 0), i2_val
= SET_SRC (set
);
2427 record_value_for_reg (i2dest
, i2_insn
, i2_val
);
2429 /* If the reg formerly set in I2 died only once and that was in I3,
2430 zero its use count so it won't make `reload' do any work. */
2432 && (newi2pat
== 0 || ! reg_mentioned_p (i2dest
, newi2pat
))
2433 && ! i2dest_in_i2src
)
2435 regno
= REGNO (i2dest
);
2436 REG_N_SETS (regno
)--;
2437 if (REG_N_SETS (regno
) == 0
2438 && ! REGNO_REG_SET_P (basic_block_live_at_start
[0], regno
))
2439 REG_N_REFS (regno
) = 0;
2443 if (i1
&& GET_CODE (i1dest
) == REG
)
2446 rtx i1_insn
= 0, i1_val
= 0, set
;
2448 for (link
= LOG_LINKS (i3
); link
; link
= XEXP (link
, 1))
2449 if ((set
= single_set (XEXP (link
, 0))) != 0
2450 && rtx_equal_p (i1dest
, SET_DEST (set
)))
2451 i1_insn
= XEXP (link
, 0), i1_val
= SET_SRC (set
);
2453 record_value_for_reg (i1dest
, i1_insn
, i1_val
);
2455 regno
= REGNO (i1dest
);
2456 if (! added_sets_1
&& ! i1dest_in_i1src
)
2458 REG_N_SETS (regno
)--;
2459 if (REG_N_SETS (regno
) == 0
2460 && ! REGNO_REG_SET_P (basic_block_live_at_start
[0], regno
))
2461 REG_N_REFS (regno
) = 0;
2465 /* Update reg_nonzero_bits et al for any changes that may have been made
2468 note_stores (newpat
, set_nonzero_bits_and_sign_copies
);
2470 note_stores (newi2pat
, set_nonzero_bits_and_sign_copies
);
2472 /* If we added any (clobber (scratch)), add them to the max for a
2473 block. This is a very pessimistic calculation, since we might
2474 have had them already and this might not be the worst block, but
2475 it's not worth doing any better. */
2476 max_scratch
+= i3_scratches
+ i2_scratches
+ other_scratches
;
2478 /* If I3 is now an unconditional jump, ensure that it has a
2479 BARRIER following it since it may have initially been a
2480 conditional jump. It may also be the last nonnote insn. */
2482 if ((GET_CODE (newpat
) == RETURN
|| simplejump_p (i3
))
2483 && ((temp
= next_nonnote_insn (i3
)) == NULL_RTX
2484 || GET_CODE (temp
) != BARRIER
))
2485 emit_barrier_after (i3
);
2488 combine_successes
++;
2490 /* Clear this here, so that subsequent get_last_value calls are not
2492 subst_prev_insn
= NULL_RTX
;
2494 if (added_links_insn
2495 && (newi2pat
== 0 || INSN_CUID (added_links_insn
) < INSN_CUID (i2
))
2496 && INSN_CUID (added_links_insn
) < INSN_CUID (i3
))
2497 return added_links_insn
;
2499 return newi2pat
? i2
: i3
;
2502 /* Undo all the modifications recorded in undobuf. */
2507 struct undo
*undo
, *next
;
2509 for (undo
= undobuf
.undos
; undo
; undo
= next
)
2513 *undo
->where
.i
= undo
->old_contents
.i
;
2515 *undo
->where
.r
= undo
->old_contents
.r
;
2517 undo
->next
= undobuf
.frees
;
2518 undobuf
.frees
= undo
;
2521 obfree (undobuf
.storage
);
2522 undobuf
.undos
= undobuf
.previous_undos
= 0;
2524 /* Clear this here, so that subsequent get_last_value calls are not
2526 subst_prev_insn
= NULL_RTX
;
2529 /* Find the innermost point within the rtx at LOC, possibly LOC itself,
2530 where we have an arithmetic expression and return that point. LOC will
2533 try_combine will call this function to see if an insn can be split into
2537 find_split_point (loc
, insn
)
2542 enum rtx_code code
= GET_CODE (x
);
2544 int len
= 0, pos
, unsignedp
;
2547 /* First special-case some codes. */
2551 #ifdef INSN_SCHEDULING
2552 /* If we are making a paradoxical SUBREG invalid, it becomes a split
2554 if (GET_CODE (SUBREG_REG (x
)) == MEM
)
2557 return find_split_point (&SUBREG_REG (x
), insn
);
2561 /* If we have (mem (const ..)) or (mem (symbol_ref ...)), split it
2562 using LO_SUM and HIGH. */
2563 if (GET_CODE (XEXP (x
, 0)) == CONST
2564 || GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
)
2567 gen_rtx_combine (LO_SUM
, Pmode
,
2568 gen_rtx_combine (HIGH
, Pmode
, XEXP (x
, 0)),
2570 return &XEXP (XEXP (x
, 0), 0);
2574 /* If we have a PLUS whose second operand is a constant and the
2575 address is not valid, perhaps will can split it up using
2576 the machine-specific way to split large constants. We use
2577 the first pseudo-reg (one of the virtual regs) as a placeholder;
2578 it will not remain in the result. */
2579 if (GET_CODE (XEXP (x
, 0)) == PLUS
2580 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
2581 && ! memory_address_p (GET_MODE (x
), XEXP (x
, 0)))
2583 rtx reg
= regno_reg_rtx
[FIRST_PSEUDO_REGISTER
];
2584 rtx seq
= split_insns (gen_rtx (SET
, VOIDmode
, reg
, XEXP (x
, 0)),
2587 /* This should have produced two insns, each of which sets our
2588 placeholder. If the source of the second is a valid address,
2589 we can make put both sources together and make a split point
2592 if (seq
&& XVECLEN (seq
, 0) == 2
2593 && GET_CODE (XVECEXP (seq
, 0, 0)) == INSN
2594 && GET_CODE (PATTERN (XVECEXP (seq
, 0, 0))) == SET
2595 && SET_DEST (PATTERN (XVECEXP (seq
, 0, 0))) == reg
2596 && ! reg_mentioned_p (reg
,
2597 SET_SRC (PATTERN (XVECEXP (seq
, 0, 0))))
2598 && GET_CODE (XVECEXP (seq
, 0, 1)) == INSN
2599 && GET_CODE (PATTERN (XVECEXP (seq
, 0, 1))) == SET
2600 && SET_DEST (PATTERN (XVECEXP (seq
, 0, 1))) == reg
2601 && memory_address_p (GET_MODE (x
),
2602 SET_SRC (PATTERN (XVECEXP (seq
, 0, 1)))))
2604 rtx src1
= SET_SRC (PATTERN (XVECEXP (seq
, 0, 0)));
2605 rtx src2
= SET_SRC (PATTERN (XVECEXP (seq
, 0, 1)));
2607 /* Replace the placeholder in SRC2 with SRC1. If we can
2608 find where in SRC2 it was placed, that can become our
2609 split point and we can replace this address with SRC2.
2610 Just try two obvious places. */
2612 src2
= replace_rtx (src2
, reg
, src1
);
2614 if (XEXP (src2
, 0) == src1
)
2615 split
= &XEXP (src2
, 0);
2616 else if (GET_RTX_FORMAT (GET_CODE (XEXP (src2
, 0)))[0] == 'e'
2617 && XEXP (XEXP (src2
, 0), 0) == src1
)
2618 split
= &XEXP (XEXP (src2
, 0), 0);
2622 SUBST (XEXP (x
, 0), src2
);
2627 /* If that didn't work, perhaps the first operand is complex and
2628 needs to be computed separately, so make a split point there.
2629 This will occur on machines that just support REG + CONST
2630 and have a constant moved through some previous computation. */
2632 else if (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (x
, 0), 0))) != 'o'
2633 && ! (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SUBREG
2634 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (XEXP (x
, 0), 0))))
2636 return &XEXP (XEXP (x
, 0), 0);
2642 /* If SET_DEST is CC0 and SET_SRC is not an operand, a COMPARE, or a
2643 ZERO_EXTRACT, the most likely reason why this doesn't match is that
2644 we need to put the operand into a register. So split at that
2647 if (SET_DEST (x
) == cc0_rtx
2648 && GET_CODE (SET_SRC (x
)) != COMPARE
2649 && GET_CODE (SET_SRC (x
)) != ZERO_EXTRACT
2650 && GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) != 'o'
2651 && ! (GET_CODE (SET_SRC (x
)) == SUBREG
2652 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (SET_SRC (x
)))) == 'o'))
2653 return &SET_SRC (x
);
2656 /* See if we can split SET_SRC as it stands. */
2657 split
= find_split_point (&SET_SRC (x
), insn
);
2658 if (split
&& split
!= &SET_SRC (x
))
2661 /* See if we can split SET_DEST as it stands. */
2662 split
= find_split_point (&SET_DEST (x
), insn
);
2663 if (split
&& split
!= &SET_DEST (x
))
2666 /* See if this is a bitfield assignment with everything constant. If
2667 so, this is an IOR of an AND, so split it into that. */
2668 if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
2669 && (GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x
), 0)))
2670 <= HOST_BITS_PER_WIDE_INT
)
2671 && GET_CODE (XEXP (SET_DEST (x
), 1)) == CONST_INT
2672 && GET_CODE (XEXP (SET_DEST (x
), 2)) == CONST_INT
2673 && GET_CODE (SET_SRC (x
)) == CONST_INT
2674 && ((INTVAL (XEXP (SET_DEST (x
), 1))
2675 + INTVAL (XEXP (SET_DEST (x
), 2)))
2676 <= GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x
), 0))))
2677 && ! side_effects_p (XEXP (SET_DEST (x
), 0)))
2679 int pos
= INTVAL (XEXP (SET_DEST (x
), 2));
2680 int len
= INTVAL (XEXP (SET_DEST (x
), 1));
2681 int src
= INTVAL (SET_SRC (x
));
2682 rtx dest
= XEXP (SET_DEST (x
), 0);
2683 enum machine_mode mode
= GET_MODE (dest
);
2684 unsigned HOST_WIDE_INT mask
= ((HOST_WIDE_INT
) 1 << len
) - 1;
2686 if (BITS_BIG_ENDIAN
)
2687 pos
= GET_MODE_BITSIZE (mode
) - len
- pos
;
2691 gen_binary (IOR
, mode
, dest
, GEN_INT (src
<< pos
)));
2694 gen_binary (IOR
, mode
,
2695 gen_binary (AND
, mode
, dest
,
2696 GEN_INT (~ (mask
<< pos
)
2697 & GET_MODE_MASK (mode
))),
2698 GEN_INT (src
<< pos
)));
2700 SUBST (SET_DEST (x
), dest
);
2702 split
= find_split_point (&SET_SRC (x
), insn
);
2703 if (split
&& split
!= &SET_SRC (x
))
2707 /* Otherwise, see if this is an operation that we can split into two.
2708 If so, try to split that. */
2709 code
= GET_CODE (SET_SRC (x
));
2714 /* If we are AND'ing with a large constant that is only a single
2715 bit and the result is only being used in a context where we
2716 need to know if it is zero or non-zero, replace it with a bit
2717 extraction. This will avoid the large constant, which might
2718 have taken more than one insn to make. If the constant were
2719 not a valid argument to the AND but took only one insn to make,
2720 this is no worse, but if it took more than one insn, it will
2723 if (GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
2724 && GET_CODE (XEXP (SET_SRC (x
), 0)) == REG
2725 && (pos
= exact_log2 (INTVAL (XEXP (SET_SRC (x
), 1)))) >= 7
2726 && GET_CODE (SET_DEST (x
)) == REG
2727 && (split
= find_single_use (SET_DEST (x
), insn
, NULL_PTR
)) != 0
2728 && (GET_CODE (*split
) == EQ
|| GET_CODE (*split
) == NE
)
2729 && XEXP (*split
, 0) == SET_DEST (x
)
2730 && XEXP (*split
, 1) == const0_rtx
)
2732 rtx extraction
= make_extraction (GET_MODE (SET_DEST (x
)),
2733 XEXP (SET_SRC (x
), 0),
2734 pos
, NULL_RTX
, 1, 1, 0, 0);
2735 if (extraction
!= 0)
2737 SUBST (SET_SRC (x
), extraction
);
2738 return find_split_point (loc
, insn
);
2744 /* if STORE_FLAG_VALUE is -1, this is (NE X 0) and only one bit of X
2745 is known to be on, this can be converted into a NEG of a shift. */
2746 if (STORE_FLAG_VALUE
== -1 && XEXP (SET_SRC (x
), 1) == const0_rtx
2747 && GET_MODE (SET_SRC (x
)) == GET_MODE (XEXP (SET_SRC (x
), 0))
2748 && 1 <= (pos
= exact_log2
2749 (nonzero_bits (XEXP (SET_SRC (x
), 0),
2750 GET_MODE (XEXP (SET_SRC (x
), 0))))))
2752 enum machine_mode mode
= GET_MODE (XEXP (SET_SRC (x
), 0));
2755 gen_rtx_combine (NEG
, mode
,
2756 gen_rtx_combine (LSHIFTRT
, mode
,
2757 XEXP (SET_SRC (x
), 0),
2760 split
= find_split_point (&SET_SRC (x
), insn
);
2761 if (split
&& split
!= &SET_SRC (x
))
2767 inner
= XEXP (SET_SRC (x
), 0);
2769 /* We can't optimize if either mode is a partial integer
2770 mode as we don't know how many bits are significant
2772 if (GET_MODE_CLASS (GET_MODE (inner
)) == MODE_PARTIAL_INT
2773 || GET_MODE_CLASS (GET_MODE (SET_SRC (x
))) == MODE_PARTIAL_INT
)
2777 len
= GET_MODE_BITSIZE (GET_MODE (inner
));
2783 if (GET_CODE (XEXP (SET_SRC (x
), 1)) == CONST_INT
2784 && GET_CODE (XEXP (SET_SRC (x
), 2)) == CONST_INT
)
2786 inner
= XEXP (SET_SRC (x
), 0);
2787 len
= INTVAL (XEXP (SET_SRC (x
), 1));
2788 pos
= INTVAL (XEXP (SET_SRC (x
), 2));
2790 if (BITS_BIG_ENDIAN
)
2791 pos
= GET_MODE_BITSIZE (GET_MODE (inner
)) - len
- pos
;
2792 unsignedp
= (code
== ZERO_EXTRACT
);
2800 if (len
&& pos
>= 0 && pos
+ len
<= GET_MODE_BITSIZE (GET_MODE (inner
)))
2802 enum machine_mode mode
= GET_MODE (SET_SRC (x
));
2804 /* For unsigned, we have a choice of a shift followed by an
2805 AND or two shifts. Use two shifts for field sizes where the
2806 constant might be too large. We assume here that we can
2807 always at least get 8-bit constants in an AND insn, which is
2808 true for every current RISC. */
2810 if (unsignedp
&& len
<= 8)
2815 gen_rtx_combine (LSHIFTRT
, mode
,
2816 gen_lowpart_for_combine (mode
, inner
),
2818 GEN_INT (((HOST_WIDE_INT
) 1 << len
) - 1)));
2820 split
= find_split_point (&SET_SRC (x
), insn
);
2821 if (split
&& split
!= &SET_SRC (x
))
2828 (unsignedp
? LSHIFTRT
: ASHIFTRT
, mode
,
2829 gen_rtx_combine (ASHIFT
, mode
,
2830 gen_lowpart_for_combine (mode
, inner
),
2831 GEN_INT (GET_MODE_BITSIZE (mode
)
2833 GEN_INT (GET_MODE_BITSIZE (mode
) - len
)));
2835 split
= find_split_point (&SET_SRC (x
), insn
);
2836 if (split
&& split
!= &SET_SRC (x
))
2841 /* See if this is a simple operation with a constant as the second
2842 operand. It might be that this constant is out of range and hence
2843 could be used as a split point. */
2844 if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == '2'
2845 || GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == 'c'
2846 || GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == '<')
2847 && CONSTANT_P (XEXP (SET_SRC (x
), 1))
2848 && (GET_RTX_CLASS (GET_CODE (XEXP (SET_SRC (x
), 0))) == 'o'
2849 || (GET_CODE (XEXP (SET_SRC (x
), 0)) == SUBREG
2850 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (SET_SRC (x
), 0))))
2852 return &XEXP (SET_SRC (x
), 1);
2854 /* Finally, see if this is a simple operation with its first operand
2855 not in a register. The operation might require this operand in a
2856 register, so return it as a split point. We can always do this
2857 because if the first operand were another operation, we would have
2858 already found it as a split point. */
2859 if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == '2'
2860 || GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == 'c'
2861 || GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == '<'
2862 || GET_RTX_CLASS (GET_CODE (SET_SRC (x
))) == '1')
2863 && ! register_operand (XEXP (SET_SRC (x
), 0), VOIDmode
))
2864 return &XEXP (SET_SRC (x
), 0);
2870 /* We write NOR as (and (not A) (not B)), but if we don't have a NOR,
2871 it is better to write this as (not (ior A B)) so we can split it.
2872 Similarly for IOR. */
2873 if (GET_CODE (XEXP (x
, 0)) == NOT
&& GET_CODE (XEXP (x
, 1)) == NOT
)
2876 gen_rtx_combine (NOT
, GET_MODE (x
),
2877 gen_rtx_combine (code
== IOR
? AND
: IOR
,
2879 XEXP (XEXP (x
, 0), 0),
2880 XEXP (XEXP (x
, 1), 0))));
2881 return find_split_point (loc
, insn
);
2884 /* Many RISC machines have a large set of logical insns. If the
2885 second operand is a NOT, put it first so we will try to split the
2886 other operand first. */
2887 if (GET_CODE (XEXP (x
, 1)) == NOT
)
2889 rtx tem
= XEXP (x
, 0);
2890 SUBST (XEXP (x
, 0), XEXP (x
, 1));
2891 SUBST (XEXP (x
, 1), tem
);
2899 /* Otherwise, select our actions depending on our rtx class. */
2900 switch (GET_RTX_CLASS (code
))
2902 case 'b': /* This is ZERO_EXTRACT and SIGN_EXTRACT. */
2904 split
= find_split_point (&XEXP (x
, 2), insn
);
2907 /* ... fall through ... */
2911 split
= find_split_point (&XEXP (x
, 1), insn
);
2914 /* ... fall through ... */
2916 /* Some machines have (and (shift ...) ...) insns. If X is not
2917 an AND, but XEXP (X, 0) is, use it as our split point. */
2918 if (GET_CODE (x
) != AND
&& GET_CODE (XEXP (x
, 0)) == AND
)
2919 return &XEXP (x
, 0);
2921 split
= find_split_point (&XEXP (x
, 0), insn
);
2927 /* Otherwise, we don't have a split point. */
2931 /* Throughout X, replace FROM with TO, and return the result.
2932 The result is TO if X is FROM;
2933 otherwise the result is X, but its contents may have been modified.
2934 If they were modified, a record was made in undobuf so that
2935 undo_all will (among other things) return X to its original state.
2937 If the number of changes necessary is too much to record to undo,
2938 the excess changes are not made, so the result is invalid.
2939 The changes already made can still be undone.
2940 undobuf.num_undo is incremented for such changes, so by testing that
2941 the caller can tell whether the result is valid.
2943 `n_occurrences' is incremented each time FROM is replaced.
2945 IN_DEST is non-zero if we are processing the SET_DEST of a SET.
2947 UNIQUE_COPY is non-zero if each substitution must be unique. We do this
2948 by copying if `n_occurrences' is non-zero. */
2951 subst (x
, from
, to
, in_dest
, unique_copy
)
2952 register rtx x
, from
, to
;
2956 register enum rtx_code code
= GET_CODE (x
);
2957 enum machine_mode op0_mode
= VOIDmode
;
2959 register int len
, i
;
2962 /* Two expressions are equal if they are identical copies of a shared
2963 RTX or if they are both registers with the same register number
2966 #define COMBINE_RTX_EQUAL_P(X,Y) \
2968 || (GET_CODE (X) == REG && GET_CODE (Y) == REG \
2969 && REGNO (X) == REGNO (Y) && GET_MODE (X) == GET_MODE (Y)))
2971 if (! in_dest
&& COMBINE_RTX_EQUAL_P (x
, from
))
2974 return (unique_copy
&& n_occurrences
> 1 ? copy_rtx (to
) : to
);
2977 /* If X and FROM are the same register but different modes, they will
2978 not have been seen as equal above. However, flow.c will make a
2979 LOG_LINKS entry for that case. If we do nothing, we will try to
2980 rerecognize our original insn and, when it succeeds, we will
2981 delete the feeding insn, which is incorrect.
2983 So force this insn not to match in this (rare) case. */
2984 if (! in_dest
&& code
== REG
&& GET_CODE (from
) == REG
2985 && REGNO (x
) == REGNO (from
))
2986 return gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
);
2988 /* If this is an object, we are done unless it is a MEM or LO_SUM, both
2989 of which may contain things that can be combined. */
2990 if (code
!= MEM
&& code
!= LO_SUM
&& GET_RTX_CLASS (code
) == 'o')
2993 /* It is possible to have a subexpression appear twice in the insn.
2994 Suppose that FROM is a register that appears within TO.
2995 Then, after that subexpression has been scanned once by `subst',
2996 the second time it is scanned, TO may be found. If we were
2997 to scan TO here, we would find FROM within it and create a
2998 self-referent rtl structure which is completely wrong. */
2999 if (COMBINE_RTX_EQUAL_P (x
, to
))
3002 len
= GET_RTX_LENGTH (code
);
3003 fmt
= GET_RTX_FORMAT (code
);
3005 /* We don't need to process a SET_DEST that is a register, CC0, or PC, so
3006 set up to skip this common case. All other cases where we want to
3007 suppress replacing something inside a SET_SRC are handled via the
3010 && (GET_CODE (SET_DEST (x
)) == REG
3011 || GET_CODE (SET_DEST (x
)) == CC0
3012 || GET_CODE (SET_DEST (x
)) == PC
))
3015 /* Get the mode of operand 0 in case X is now a SIGN_EXTEND of a
3018 op0_mode
= GET_MODE (XEXP (x
, 0));
3020 for (i
= 0; i
< len
; i
++)
3025 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3027 if (COMBINE_RTX_EQUAL_P (XVECEXP (x
, i
, j
), from
))
3029 new = (unique_copy
&& n_occurrences
? copy_rtx (to
) : to
);
3034 new = subst (XVECEXP (x
, i
, j
), from
, to
, 0, unique_copy
);
3036 /* If this substitution failed, this whole thing fails. */
3037 if (GET_CODE (new) == CLOBBER
&& XEXP (new, 0) == const0_rtx
)
3041 SUBST (XVECEXP (x
, i
, j
), new);
3044 else if (fmt
[i
] == 'e')
3046 if (COMBINE_RTX_EQUAL_P (XEXP (x
, i
), from
))
3048 /* In general, don't install a subreg involving two modes not
3049 tieable. It can worsen register allocation, and can even
3050 make invalid reload insns, since the reg inside may need to
3051 be copied from in the outside mode, and that may be invalid
3052 if it is an fp reg copied in integer mode.
3054 We allow two exceptions to this: It is valid if it is inside
3055 another SUBREG and the mode of that SUBREG and the mode of
3056 the inside of TO is tieable and it is valid if X is a SET
3057 that copies FROM to CC0. */
3058 if (GET_CODE (to
) == SUBREG
3059 && ! MODES_TIEABLE_P (GET_MODE (to
),
3060 GET_MODE (SUBREG_REG (to
)))
3061 && ! (code
== SUBREG
3062 && MODES_TIEABLE_P (GET_MODE (x
),
3063 GET_MODE (SUBREG_REG (to
))))
3065 && ! (code
== SET
&& i
== 1 && XEXP (x
, 0) == cc0_rtx
)
3068 return gen_rtx (CLOBBER
, VOIDmode
, const0_rtx
);
3070 new = (unique_copy
&& n_occurrences
? copy_rtx (to
) : to
);
3074 /* If we are in a SET_DEST, suppress most cases unless we
3075 have gone inside a MEM, in which case we want to
3076 simplify the address. We assume here that things that
3077 are actually part of the destination have their inner
3078 parts in the first expression. This is true for SUBREG,
3079 STRICT_LOW_PART, and ZERO_EXTRACT, which are the only
3080 things aside from REG and MEM that should appear in a
3082 new = subst (XEXP (x
, i
), from
, to
,
3084 && (code
== SUBREG
|| code
== STRICT_LOW_PART
3085 || code
== ZERO_EXTRACT
))
3087 && i
== 0), unique_copy
);
3089 /* If we found that we will have to reject this combination,
3090 indicate that by returning the CLOBBER ourselves, rather than
3091 an expression containing it. This will speed things up as
3092 well as prevent accidents where two CLOBBERs are considered
3093 to be equal, thus producing an incorrect simplification. */
3095 if (GET_CODE (new) == CLOBBER
&& XEXP (new, 0) == const0_rtx
)
3098 SUBST (XEXP (x
, i
), new);
3102 /* Try to simplify X. If the simplification changed the code, it is likely
3103 that further simplification will help, so loop, but limit the number
3104 of repetitions that will be performed. */
3106 for (i
= 0; i
< 4; i
++)
3108 /* If X is sufficiently simple, don't bother trying to do anything
3110 if (code
!= CONST_INT
&& code
!= REG
&& code
!= CLOBBER
)
3111 x
= simplify_rtx (x
, op0_mode
, i
== 3, in_dest
);
3113 if (GET_CODE (x
) == code
)
3116 code
= GET_CODE (x
);
3118 /* We no longer know the original mode of operand 0 since we
3119 have changed the form of X) */
3120 op0_mode
= VOIDmode
;
3126 /* Simplify X, a piece of RTL. We just operate on the expression at the
3127 outer level; call `subst' to simplify recursively. Return the new
3130 OP0_MODE is the original mode of XEXP (x, 0); LAST is nonzero if this
3131 will be the iteration even if an expression with a code different from
3132 X is returned; IN_DEST is nonzero if we are inside a SET_DEST. */
3135 simplify_rtx (x
, op0_mode
, last
, in_dest
)
3137 enum machine_mode op0_mode
;
3141 enum rtx_code code
= GET_CODE (x
);
3142 enum machine_mode mode
= GET_MODE (x
);
3146 /* If this is a commutative operation, put a constant last and a complex
3147 expression first. We don't need to do this for comparisons here. */
3148 if (GET_RTX_CLASS (code
) == 'c'
3149 && ((CONSTANT_P (XEXP (x
, 0)) && GET_CODE (XEXP (x
, 1)) != CONST_INT
)
3150 || (GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == 'o'
3151 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 1))) != 'o')
3152 || (GET_CODE (XEXP (x
, 0)) == SUBREG
3153 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x
, 0)))) == 'o'
3154 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 1))) != 'o')))
3157 SUBST (XEXP (x
, 0), XEXP (x
, 1));
3158 SUBST (XEXP (x
, 1), temp
);
3161 /* If this is a PLUS, MINUS, or MULT, and the first operand is the
3162 sign extension of a PLUS with a constant, reverse the order of the sign
3163 extension and the addition. Note that this not the same as the original
3164 code, but overflow is undefined for signed values. Also note that the
3165 PLUS will have been partially moved "inside" the sign-extension, so that
3166 the first operand of X will really look like:
3167 (ashiftrt (plus (ashift A C4) C5) C4).
3169 (plus (ashiftrt (ashift A C4) C2) C4)
3170 and replace the first operand of X with that expression. Later parts
3171 of this function may simplify the expression further.
3173 For example, if we start with (mult (sign_extend (plus A C1)) C2),
3174 we swap the SIGN_EXTEND and PLUS. Later code will apply the
3175 distributive law to produce (plus (mult (sign_extend X) C1) C3).
3177 We do this to simplify address expressions. */
3179 if ((code
== PLUS
|| code
== MINUS
|| code
== MULT
)
3180 && GET_CODE (XEXP (x
, 0)) == ASHIFTRT
3181 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == PLUS
3182 && GET_CODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)) == ASHIFT
3183 && GET_CODE (XEXP (XEXP (XEXP (XEXP (x
, 0), 0), 0), 1)) == CONST_INT
3184 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
3185 && XEXP (XEXP (XEXP (XEXP (x
, 0), 0), 0), 1) == XEXP (XEXP (x
, 0), 1)
3186 && GET_CODE (XEXP (XEXP (XEXP (x
, 0), 0), 1)) == CONST_INT
3187 && (temp
= simplify_binary_operation (ASHIFTRT
, mode
,
3188 XEXP (XEXP (XEXP (x
, 0), 0), 1),
3189 XEXP (XEXP (x
, 0), 1))) != 0)
3192 = simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
3193 XEXP (XEXP (XEXP (XEXP (x
, 0), 0), 0), 0),
3194 INTVAL (XEXP (XEXP (x
, 0), 1)));
3196 new = simplify_shift_const (NULL_RTX
, ASHIFTRT
, mode
, new,
3197 INTVAL (XEXP (XEXP (x
, 0), 1)));
3199 SUBST (XEXP (x
, 0), gen_binary (PLUS
, mode
, new, temp
));
3202 /* If this is a simple operation applied to an IF_THEN_ELSE, try
3203 applying it to the arms of the IF_THEN_ELSE. This often simplifies
3204 things. Check for cases where both arms are testing the same
3207 Don't do anything if all operands are very simple. */
3209 if (((GET_RTX_CLASS (code
) == '2' || GET_RTX_CLASS (code
) == 'c'
3210 || GET_RTX_CLASS (code
) == '<')
3211 && ((GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) != 'o'
3212 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
3213 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x
, 0))))
3215 || (GET_RTX_CLASS (GET_CODE (XEXP (x
, 1))) != 'o'
3216 && ! (GET_CODE (XEXP (x
, 1)) == SUBREG
3217 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x
, 1))))
3219 || (GET_RTX_CLASS (code
) == '1'
3220 && ((GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) != 'o'
3221 && ! (GET_CODE (XEXP (x
, 0)) == SUBREG
3222 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x
, 0))))
3225 rtx cond
, true, false;
3227 cond
= if_then_else_cond (x
, &true, &false);
3229 /* If everything is a comparison, what we have is highly unlikely
3230 to be simpler, so don't use it. */
3231 && ! (GET_RTX_CLASS (code
) == '<'
3232 && (GET_RTX_CLASS (GET_CODE (true)) == '<'
3233 || GET_RTX_CLASS (GET_CODE (false)) == '<')))
3235 rtx cop1
= const0_rtx
;
3236 enum rtx_code cond_code
= simplify_comparison (NE
, &cond
, &cop1
);
3238 if (cond_code
== NE
&& GET_RTX_CLASS (GET_CODE (cond
)) == '<')
3241 /* Simplify the alternative arms; this may collapse the true and
3242 false arms to store-flag values. */
3243 true = subst (true, pc_rtx
, pc_rtx
, 0, 0);
3244 false = subst (false, pc_rtx
, pc_rtx
, 0, 0);
3246 /* Restarting if we generate a store-flag expression will cause
3247 us to loop. Just drop through in this case. */
3249 /* If the result values are STORE_FLAG_VALUE and zero, we can
3250 just make the comparison operation. */
3251 if (true == const_true_rtx
&& false == const0_rtx
)
3252 x
= gen_binary (cond_code
, mode
, cond
, cop1
);
3253 else if (true == const0_rtx
&& false == const_true_rtx
)
3254 x
= gen_binary (reverse_condition (cond_code
), mode
, cond
, cop1
);
3256 /* Likewise, we can make the negate of a comparison operation
3257 if the result values are - STORE_FLAG_VALUE and zero. */
3258 else if (GET_CODE (true) == CONST_INT
3259 && INTVAL (true) == - STORE_FLAG_VALUE
3260 && false == const0_rtx
)
3261 x
= gen_unary (NEG
, mode
, mode
,
3262 gen_binary (cond_code
, mode
, cond
, cop1
));
3263 else if (GET_CODE (false) == CONST_INT
3264 && INTVAL (false) == - STORE_FLAG_VALUE
3265 && true == const0_rtx
)
3266 x
= gen_unary (NEG
, mode
, mode
,
3267 gen_binary (reverse_condition (cond_code
),
3270 return gen_rtx (IF_THEN_ELSE
, mode
,
3271 gen_binary (cond_code
, VOIDmode
, cond
, cop1
),
3274 code
= GET_CODE (x
);
3275 op0_mode
= VOIDmode
;
3279 /* Try to fold this expression in case we have constants that weren't
3282 switch (GET_RTX_CLASS (code
))
3285 temp
= simplify_unary_operation (code
, mode
, XEXP (x
, 0), op0_mode
);
3288 temp
= simplify_relational_operation (code
, op0_mode
,
3289 XEXP (x
, 0), XEXP (x
, 1));
3290 #ifdef FLOAT_STORE_FLAG_VALUE
3291 if (temp
!= 0 && GET_MODE_CLASS (GET_MODE (x
)) == MODE_FLOAT
)
3292 temp
= ((temp
== const0_rtx
) ? CONST0_RTX (GET_MODE (x
))
3293 : immed_real_const_1 (FLOAT_STORE_FLAG_VALUE
, GET_MODE (x
)));
3298 temp
= simplify_binary_operation (code
, mode
, XEXP (x
, 0), XEXP (x
, 1));
3302 temp
= simplify_ternary_operation (code
, mode
, op0_mode
, XEXP (x
, 0),
3303 XEXP (x
, 1), XEXP (x
, 2));
3308 x
= temp
, code
= GET_CODE (temp
);
3310 /* First see if we can apply the inverse distributive law. */
3311 if (code
== PLUS
|| code
== MINUS
3312 || code
== AND
|| code
== IOR
|| code
== XOR
)
3314 x
= apply_distributive_law (x
);
3315 code
= GET_CODE (x
);
3318 /* If CODE is an associative operation not otherwise handled, see if we
3319 can associate some operands. This can win if they are constants or
3320 if they are logically related (i.e. (a & b) & a. */
3321 if ((code
== PLUS
|| code
== MINUS
3322 || code
== MULT
|| code
== AND
|| code
== IOR
|| code
== XOR
3323 || code
== DIV
|| code
== UDIV
3324 || code
== SMAX
|| code
== SMIN
|| code
== UMAX
|| code
== UMIN
)
3325 && INTEGRAL_MODE_P (mode
))
3327 if (GET_CODE (XEXP (x
, 0)) == code
)
3329 rtx other
= XEXP (XEXP (x
, 0), 0);
3330 rtx inner_op0
= XEXP (XEXP (x
, 0), 1);
3331 rtx inner_op1
= XEXP (x
, 1);
3334 /* Make sure we pass the constant operand if any as the second
3335 one if this is a commutative operation. */
3336 if (CONSTANT_P (inner_op0
) && GET_RTX_CLASS (code
) == 'c')
3338 rtx tem
= inner_op0
;
3339 inner_op0
= inner_op1
;
3342 inner
= simplify_binary_operation (code
== MINUS
? PLUS
3343 : code
== DIV
? MULT
3344 : code
== UDIV
? MULT
3346 mode
, inner_op0
, inner_op1
);
3348 /* For commutative operations, try the other pair if that one
3350 if (inner
== 0 && GET_RTX_CLASS (code
) == 'c')
3352 other
= XEXP (XEXP (x
, 0), 1);
3353 inner
= simplify_binary_operation (code
, mode
,
3354 XEXP (XEXP (x
, 0), 0),
3359 return gen_binary (code
, mode
, other
, inner
);
3363 /* A little bit of algebraic simplification here. */
3367 /* Ensure that our address has any ASHIFTs converted to MULT in case
3368 address-recognizing predicates are called later. */
3369 temp
= make_compound_operation (XEXP (x
, 0), MEM
);
3370 SUBST (XEXP (x
, 0), temp
);
3374 /* (subreg:A (mem:B X) N) becomes a modified MEM unless the SUBREG
3375 is paradoxical. If we can't do that safely, then it becomes
3376 something nonsensical so that this combination won't take place. */
3378 if (GET_CODE (SUBREG_REG (x
)) == MEM
3379 && (GET_MODE_SIZE (mode
)
3380 <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
)))))
3382 rtx inner
= SUBREG_REG (x
);
3383 int endian_offset
= 0;
3384 /* Don't change the mode of the MEM
3385 if that would change the meaning of the address. */
3386 if (MEM_VOLATILE_P (SUBREG_REG (x
))
3387 || mode_dependent_address_p (XEXP (inner
, 0)))
3388 return gen_rtx (CLOBBER
, mode
, const0_rtx
);
3390 if (BYTES_BIG_ENDIAN
)
3392 if (GET_MODE_SIZE (mode
) < UNITS_PER_WORD
)
3393 endian_offset
+= UNITS_PER_WORD
- GET_MODE_SIZE (mode
);
3394 if (GET_MODE_SIZE (GET_MODE (inner
)) < UNITS_PER_WORD
)
3395 endian_offset
-= (UNITS_PER_WORD
3396 - GET_MODE_SIZE (GET_MODE (inner
)));
3398 /* Note if the plus_constant doesn't make a valid address
3399 then this combination won't be accepted. */
3400 x
= gen_rtx (MEM
, mode
,
3401 plus_constant (XEXP (inner
, 0),
3402 (SUBREG_WORD (x
) * UNITS_PER_WORD
3404 MEM_VOLATILE_P (x
) = MEM_VOLATILE_P (inner
);
3405 RTX_UNCHANGING_P (x
) = RTX_UNCHANGING_P (inner
);
3406 MEM_IN_STRUCT_P (x
) = MEM_IN_STRUCT_P (inner
);
3410 /* If we are in a SET_DEST, these other cases can't apply. */
3414 /* Changing mode twice with SUBREG => just change it once,
3415 or not at all if changing back to starting mode. */
3416 if (GET_CODE (SUBREG_REG (x
)) == SUBREG
)
3418 if (mode
== GET_MODE (SUBREG_REG (SUBREG_REG (x
)))
3419 && SUBREG_WORD (x
) == 0 && SUBREG_WORD (SUBREG_REG (x
)) == 0)
3420 return SUBREG_REG (SUBREG_REG (x
));
3422 SUBST_INT (SUBREG_WORD (x
),
3423 SUBREG_WORD (x
) + SUBREG_WORD (SUBREG_REG (x
)));
3424 SUBST (SUBREG_REG (x
), SUBREG_REG (SUBREG_REG (x
)));
3427 /* SUBREG of a hard register => just change the register number
3428 and/or mode. If the hard register is not valid in that mode,
3429 suppress this combination. If the hard register is the stack,
3430 frame, or argument pointer, leave this as a SUBREG. */
3432 if (GET_CODE (SUBREG_REG (x
)) == REG
3433 && REGNO (SUBREG_REG (x
)) < FIRST_PSEUDO_REGISTER
3434 && REGNO (SUBREG_REG (x
)) != FRAME_POINTER_REGNUM
3435 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
3436 && REGNO (SUBREG_REG (x
)) != HARD_FRAME_POINTER_REGNUM
3438 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3439 && REGNO (SUBREG_REG (x
)) != ARG_POINTER_REGNUM
3441 && REGNO (SUBREG_REG (x
)) != STACK_POINTER_REGNUM
)
3443 if (HARD_REGNO_MODE_OK (REGNO (SUBREG_REG (x
)) + SUBREG_WORD (x
),
3445 return gen_rtx (REG
, mode
,
3446 REGNO (SUBREG_REG (x
)) + SUBREG_WORD (x
));
3448 return gen_rtx (CLOBBER
, mode
, const0_rtx
);
3451 /* For a constant, try to pick up the part we want. Handle a full
3452 word and low-order part. Only do this if we are narrowing
3453 the constant; if it is being widened, we have no idea what
3454 the extra bits will have been set to. */
3456 if (CONSTANT_P (SUBREG_REG (x
)) && op0_mode
!= VOIDmode
3457 && GET_MODE_SIZE (mode
) == UNITS_PER_WORD
3458 && GET_MODE_SIZE (op0_mode
) > UNITS_PER_WORD
3459 && GET_MODE_CLASS (mode
) == MODE_INT
)
3461 temp
= operand_subword (SUBREG_REG (x
), SUBREG_WORD (x
),
3467 /* If we want a subreg of a constant, at offset 0,
3468 take the low bits. On a little-endian machine, that's
3469 always valid. On a big-endian machine, it's valid
3470 only if the constant's mode fits in one word. Note that we
3471 cannot use subreg_lowpart_p since SUBREG_REG may be VOIDmode. */
3472 if (CONSTANT_P (SUBREG_REG (x
))
3473 && ((GET_MODE_SIZE (op0_mode
) <= UNITS_PER_WORD
3474 || ! WORDS_BIG_ENDIAN
)
3475 ? SUBREG_WORD (x
) == 0
3477 == ((GET_MODE_SIZE (op0_mode
)
3478 - MAX (GET_MODE_SIZE (mode
), UNITS_PER_WORD
))
3480 && GET_MODE_SIZE (mode
) <= GET_MODE_SIZE (op0_mode
)
3481 && (! WORDS_BIG_ENDIAN
3482 || GET_MODE_BITSIZE (op0_mode
) <= BITS_PER_WORD
))
3483 return gen_lowpart_for_combine (mode
, SUBREG_REG (x
));
3485 /* A paradoxical SUBREG of a VOIDmode constant is the same constant,
3486 since we are saying that the high bits don't matter. */
3487 if (CONSTANT_P (SUBREG_REG (x
)) && GET_MODE (SUBREG_REG (x
)) == VOIDmode
3488 && GET_MODE_SIZE (mode
) > GET_MODE_SIZE (op0_mode
))
3489 return SUBREG_REG (x
);
3491 /* Note that we cannot do any narrowing for non-constants since
3492 we might have been counting on using the fact that some bits were
3493 zero. We now do this in the SET. */
3498 /* (not (plus X -1)) can become (neg X). */
3499 if (GET_CODE (XEXP (x
, 0)) == PLUS
3500 && XEXP (XEXP (x
, 0), 1) == constm1_rtx
)
3501 return gen_rtx_combine (NEG
, mode
, XEXP (XEXP (x
, 0), 0));
3503 /* Similarly, (not (neg X)) is (plus X -1). */
3504 if (GET_CODE (XEXP (x
, 0)) == NEG
)
3505 return gen_rtx_combine (PLUS
, mode
, XEXP (XEXP (x
, 0), 0),
3508 /* (not (xor X C)) for C constant is (xor X D) with D = ~ C. */
3509 if (GET_CODE (XEXP (x
, 0)) == XOR
3510 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
3511 && (temp
= simplify_unary_operation (NOT
, mode
,
3512 XEXP (XEXP (x
, 0), 1),
3514 return gen_binary (XOR
, mode
, XEXP (XEXP (x
, 0), 0), temp
);
3516 /* (not (ashift 1 X)) is (rotate ~1 X). We used to do this for operands
3517 other than 1, but that is not valid. We could do a similar
3518 simplification for (not (lshiftrt C X)) where C is just the sign bit,
3519 but this doesn't seem common enough to bother with. */
3520 if (GET_CODE (XEXP (x
, 0)) == ASHIFT
3521 && XEXP (XEXP (x
, 0), 0) == const1_rtx
)
3522 return gen_rtx (ROTATE
, mode
, gen_unary (NOT
, mode
, mode
, const1_rtx
),
3523 XEXP (XEXP (x
, 0), 1));
3525 if (GET_CODE (XEXP (x
, 0)) == SUBREG
3526 && subreg_lowpart_p (XEXP (x
, 0))
3527 && (GET_MODE_SIZE (GET_MODE (XEXP (x
, 0)))
3528 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (x
, 0)))))
3529 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == ASHIFT
3530 && XEXP (SUBREG_REG (XEXP (x
, 0)), 0) == const1_rtx
)
3532 enum machine_mode inner_mode
= GET_MODE (SUBREG_REG (XEXP (x
, 0)));
3534 x
= gen_rtx (ROTATE
, inner_mode
,
3535 gen_unary (NOT
, inner_mode
, inner_mode
, const1_rtx
),
3536 XEXP (SUBREG_REG (XEXP (x
, 0)), 1));
3537 return gen_lowpart_for_combine (mode
, x
);
3540 /* If STORE_FLAG_VALUE is -1, (not (comparison foo bar)) can be done by
3541 reversing the comparison code if valid. */
3542 if (STORE_FLAG_VALUE
== -1
3543 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == '<'
3544 && reversible_comparison_p (XEXP (x
, 0)))
3545 return gen_rtx_combine (reverse_condition (GET_CODE (XEXP (x
, 0))),
3546 mode
, XEXP (XEXP (x
, 0), 0),
3547 XEXP (XEXP (x
, 0), 1));
3549 /* (ashiftrt foo C) where C is the number of bits in FOO minus 1
3550 is (lt foo (const_int 0)) if STORE_FLAG_VALUE is -1, so we can
3551 perform the above simplification. */
3553 if (STORE_FLAG_VALUE
== -1
3554 && XEXP (x
, 1) == const1_rtx
3555 && GET_CODE (XEXP (x
, 0)) == ASHIFTRT
3556 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
3557 && INTVAL (XEXP (XEXP (x
, 0), 1)) == GET_MODE_BITSIZE (mode
) - 1)
3558 return gen_rtx_combine (GE
, mode
, XEXP (XEXP (x
, 0), 0), const0_rtx
);
3560 /* Apply De Morgan's laws to reduce number of patterns for machines
3561 with negating logical insns (and-not, nand, etc.). If result has
3562 only one NOT, put it first, since that is how the patterns are
3565 if (GET_CODE (XEXP (x
, 0)) == IOR
|| GET_CODE (XEXP (x
, 0)) == AND
)
3567 rtx in1
= XEXP (XEXP (x
, 0), 0), in2
= XEXP (XEXP (x
, 0), 1);
3569 if (GET_CODE (in1
) == NOT
)
3570 in1
= XEXP (in1
, 0);
3572 in1
= gen_rtx_combine (NOT
, GET_MODE (in1
), in1
);
3574 if (GET_CODE (in2
) == NOT
)
3575 in2
= XEXP (in2
, 0);
3576 else if (GET_CODE (in2
) == CONST_INT
3577 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
)
3578 in2
= GEN_INT (GET_MODE_MASK (mode
) & ~ INTVAL (in2
));
3580 in2
= gen_rtx_combine (NOT
, GET_MODE (in2
), in2
);
3582 if (GET_CODE (in2
) == NOT
)
3585 in2
= in1
; in1
= tem
;
3588 return gen_rtx_combine (GET_CODE (XEXP (x
, 0)) == IOR
? AND
: IOR
,
3594 /* (neg (plus X 1)) can become (not X). */
3595 if (GET_CODE (XEXP (x
, 0)) == PLUS
3596 && XEXP (XEXP (x
, 0), 1) == const1_rtx
)
3597 return gen_rtx_combine (NOT
, mode
, XEXP (XEXP (x
, 0), 0));
3599 /* Similarly, (neg (not X)) is (plus X 1). */
3600 if (GET_CODE (XEXP (x
, 0)) == NOT
)
3601 return plus_constant (XEXP (XEXP (x
, 0), 0), 1);
3603 /* (neg (minus X Y)) can become (minus Y X). */
3604 if (GET_CODE (XEXP (x
, 0)) == MINUS
3605 && (! FLOAT_MODE_P (mode
)
3606 /* x-y != -(y-x) with IEEE floating point. */
3607 || TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
3609 return gen_binary (MINUS
, mode
, XEXP (XEXP (x
, 0), 1),
3610 XEXP (XEXP (x
, 0), 0));
3612 /* (neg (xor A 1)) is (plus A -1) if A is known to be either 0 or 1. */
3613 if (GET_CODE (XEXP (x
, 0)) == XOR
&& XEXP (XEXP (x
, 0), 1) == const1_rtx
3614 && nonzero_bits (XEXP (XEXP (x
, 0), 0), mode
) == 1)
3615 return gen_binary (PLUS
, mode
, XEXP (XEXP (x
, 0), 0), constm1_rtx
);
3617 /* NEG commutes with ASHIFT since it is multiplication. Only do this
3618 if we can then eliminate the NEG (e.g.,
3619 if the operand is a constant). */
3621 if (GET_CODE (XEXP (x
, 0)) == ASHIFT
)
3623 temp
= simplify_unary_operation (NEG
, mode
,
3624 XEXP (XEXP (x
, 0), 0), mode
);
3627 SUBST (XEXP (XEXP (x
, 0), 0), temp
);
3632 temp
= expand_compound_operation (XEXP (x
, 0));
3634 /* For C equal to the width of MODE minus 1, (neg (ashiftrt X C)) can be
3635 replaced by (lshiftrt X C). This will convert
3636 (neg (sign_extract X 1 Y)) to (zero_extract X 1 Y). */
3638 if (GET_CODE (temp
) == ASHIFTRT
3639 && GET_CODE (XEXP (temp
, 1)) == CONST_INT
3640 && INTVAL (XEXP (temp
, 1)) == GET_MODE_BITSIZE (mode
) - 1)
3641 return simplify_shift_const (temp
, LSHIFTRT
, mode
, XEXP (temp
, 0),
3642 INTVAL (XEXP (temp
, 1)));
3644 /* If X has only a single bit that might be nonzero, say, bit I, convert
3645 (neg X) to (ashiftrt (ashift X C-I) C-I) where C is the bitsize of
3646 MODE minus 1. This will convert (neg (zero_extract X 1 Y)) to
3647 (sign_extract X 1 Y). But only do this if TEMP isn't a register
3648 or a SUBREG of one since we'd be making the expression more
3649 complex if it was just a register. */
3651 if (GET_CODE (temp
) != REG
3652 && ! (GET_CODE (temp
) == SUBREG
3653 && GET_CODE (SUBREG_REG (temp
)) == REG
)
3654 && (i
= exact_log2 (nonzero_bits (temp
, mode
))) >= 0)
3656 rtx temp1
= simplify_shift_const
3657 (NULL_RTX
, ASHIFTRT
, mode
,
3658 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, temp
,
3659 GET_MODE_BITSIZE (mode
) - 1 - i
),
3660 GET_MODE_BITSIZE (mode
) - 1 - i
);
3662 /* If all we did was surround TEMP with the two shifts, we
3663 haven't improved anything, so don't use it. Otherwise,
3664 we are better off with TEMP1. */
3665 if (GET_CODE (temp1
) != ASHIFTRT
3666 || GET_CODE (XEXP (temp1
, 0)) != ASHIFT
3667 || XEXP (XEXP (temp1
, 0), 0) != temp
)
3673 /* We can't handle truncation to a partial integer mode here
3674 because we don't know the real bitsize of the partial
3676 if (GET_MODE_CLASS (mode
) == MODE_PARTIAL_INT
)
3679 if (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
)
3681 force_to_mode (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)),
3682 GET_MODE_MASK (mode
), NULL_RTX
, 0));
3684 /* (truncate:SI ({sign,zero}_extend:DI foo:SI)) == foo:SI. */
3685 if ((GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
3686 || GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
)
3687 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == mode
)
3688 return XEXP (XEXP (x
, 0), 0);
3690 /* (truncate:SI (OP:DI ({sign,zero}_extend:DI foo:SI))) is
3691 (OP:SI foo:SI) if OP is NEG or ABS. */
3692 if ((GET_CODE (XEXP (x
, 0)) == ABS
3693 || GET_CODE (XEXP (x
, 0)) == NEG
)
3694 && (GET_CODE (XEXP (XEXP (x
, 0), 0)) == SIGN_EXTEND
3695 || GET_CODE (XEXP (XEXP (x
, 0), 0)) == ZERO_EXTEND
)
3696 && GET_MODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)) == mode
)
3697 return gen_unary (GET_CODE (XEXP (x
, 0)), mode
, mode
,
3698 XEXP (XEXP (XEXP (x
, 0), 0), 0));
3700 /* (truncate:SI (subreg:DI (truncate:SI X) 0)) is
3702 if (GET_CODE (XEXP (x
, 0)) == SUBREG
3703 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == TRUNCATE
3704 && subreg_lowpart_p (XEXP (x
, 0)))
3705 return SUBREG_REG (XEXP (x
, 0));
3707 /* If we know that the value is already truncated, we can
3708 replace the TRUNCATE with a SUBREG. */
3709 if (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))) <= HOST_BITS_PER_WIDE_INT
3710 && (nonzero_bits (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
3711 &~ GET_MODE_MASK (mode
)) == 0)
3712 return gen_lowpart_for_combine (mode
, XEXP (x
, 0));
3714 /* A truncate of a comparison can be replaced with a subreg if
3715 STORE_FLAG_VALUE permits. This is like the previous test,
3716 but it works even if the comparison is done in a mode larger
3717 than HOST_BITS_PER_WIDE_INT. */
3718 if (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
3719 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == '<'
3720 && ((HOST_WIDE_INT
) STORE_FLAG_VALUE
&~ GET_MODE_MASK (mode
)) == 0)
3721 return gen_lowpart_for_combine (mode
, XEXP (x
, 0));
3723 /* Similarly, a truncate of a register whose value is a
3724 comparison can be replaced with a subreg if STORE_FLAG_VALUE
3726 if (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
3727 && ((HOST_WIDE_INT
) STORE_FLAG_VALUE
&~ GET_MODE_MASK (mode
)) == 0
3728 && (temp
= get_last_value (XEXP (x
, 0)))
3729 && GET_RTX_CLASS (GET_CODE (temp
)) == '<')
3730 return gen_lowpart_for_combine (mode
, XEXP (x
, 0));
3734 case FLOAT_TRUNCATE
:
3735 /* (float_truncate:SF (float_extend:DF foo:SF)) = foo:SF. */
3736 if (GET_CODE (XEXP (x
, 0)) == FLOAT_EXTEND
3737 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == mode
)
3738 return XEXP (XEXP (x
, 0), 0);
3740 /* (float_truncate:SF (OP:DF (float_extend:DF foo:sf))) is
3741 (OP:SF foo:SF) if OP is NEG or ABS. */
3742 if ((GET_CODE (XEXP (x
, 0)) == ABS
3743 || GET_CODE (XEXP (x
, 0)) == NEG
)
3744 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == FLOAT_EXTEND
3745 && GET_MODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)) == mode
)
3746 return gen_unary (GET_CODE (XEXP (x
, 0)), mode
, mode
,
3747 XEXP (XEXP (XEXP (x
, 0), 0), 0));
3749 /* (float_truncate:SF (subreg:DF (float_truncate:SF X) 0))
3750 is (float_truncate:SF x). */
3751 if (GET_CODE (XEXP (x
, 0)) == SUBREG
3752 && subreg_lowpart_p (XEXP (x
, 0))
3753 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == FLOAT_TRUNCATE
)
3754 return SUBREG_REG (XEXP (x
, 0));
3759 /* Convert (compare FOO (const_int 0)) to FOO unless we aren't
3760 using cc0, in which case we want to leave it as a COMPARE
3761 so we can distinguish it from a register-register-copy. */
3762 if (XEXP (x
, 1) == const0_rtx
)
3765 /* In IEEE floating point, x-0 is not the same as x. */
3766 if ((TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
3767 || ! FLOAT_MODE_P (GET_MODE (XEXP (x
, 0)))
3769 && XEXP (x
, 1) == CONST0_RTX (GET_MODE (XEXP (x
, 0))))
3775 /* (const (const X)) can become (const X). Do it this way rather than
3776 returning the inner CONST since CONST can be shared with a
3778 if (GET_CODE (XEXP (x
, 0)) == CONST
)
3779 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
3784 /* Convert (lo_sum (high FOO) FOO) to FOO. This is necessary so we
3785 can add in an offset. find_split_point will split this address up
3786 again if it doesn't match. */
3787 if (GET_CODE (XEXP (x
, 0)) == HIGH
3788 && rtx_equal_p (XEXP (XEXP (x
, 0), 0), XEXP (x
, 1)))
3794 /* If we have (plus (plus (A const) B)), associate it so that CONST is
3795 outermost. That's because that's the way indexed addresses are
3796 supposed to appear. This code used to check many more cases, but
3797 they are now checked elsewhere. */
3798 if (GET_CODE (XEXP (x
, 0)) == PLUS
3799 && CONSTANT_ADDRESS_P (XEXP (XEXP (x
, 0), 1)))
3800 return gen_binary (PLUS
, mode
,
3801 gen_binary (PLUS
, mode
, XEXP (XEXP (x
, 0), 0),
3803 XEXP (XEXP (x
, 0), 1));
3805 /* (plus (xor (and <foo> (const_int pow2 - 1)) <c>) <-c>)
3806 when c is (const_int (pow2 + 1) / 2) is a sign extension of a
3807 bit-field and can be replaced by either a sign_extend or a
3808 sign_extract. The `and' may be a zero_extend. */
3809 if (GET_CODE (XEXP (x
, 0)) == XOR
3810 && GET_CODE (XEXP (x
, 1)) == CONST_INT
3811 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
3812 && INTVAL (XEXP (x
, 1)) == - INTVAL (XEXP (XEXP (x
, 0), 1))
3813 && (i
= exact_log2 (INTVAL (XEXP (XEXP (x
, 0), 1)))) >= 0
3814 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
3815 && ((GET_CODE (XEXP (XEXP (x
, 0), 0)) == AND
3816 && GET_CODE (XEXP (XEXP (XEXP (x
, 0), 0), 1)) == CONST_INT
3817 && (INTVAL (XEXP (XEXP (XEXP (x
, 0), 0), 1))
3818 == ((HOST_WIDE_INT
) 1 << (i
+ 1)) - 1))
3819 || (GET_CODE (XEXP (XEXP (x
, 0), 0)) == ZERO_EXTEND
3820 && (GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (XEXP (x
, 0), 0), 0)))
3822 return simplify_shift_const
3823 (NULL_RTX
, ASHIFTRT
, mode
,
3824 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
3825 XEXP (XEXP (XEXP (x
, 0), 0), 0),
3826 GET_MODE_BITSIZE (mode
) - (i
+ 1)),
3827 GET_MODE_BITSIZE (mode
) - (i
+ 1));
3829 /* (plus (comparison A B) C) can become (neg (rev-comp A B)) if
3830 C is 1 and STORE_FLAG_VALUE is -1 or if C is -1 and STORE_FLAG_VALUE
3831 is 1. This produces better code than the alternative immediately
3833 if (GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == '<'
3834 && reversible_comparison_p (XEXP (x
, 0))
3835 && ((STORE_FLAG_VALUE
== -1 && XEXP (x
, 1) == const1_rtx
)
3836 || (STORE_FLAG_VALUE
== 1 && XEXP (x
, 1) == constm1_rtx
)))
3838 gen_unary (NEG
, mode
, mode
,
3839 gen_binary (reverse_condition (GET_CODE (XEXP (x
, 0))),
3840 mode
, XEXP (XEXP (x
, 0), 0),
3841 XEXP (XEXP (x
, 0), 1)));
3843 /* If only the low-order bit of X is possibly nonzero, (plus x -1)
3844 can become (ashiftrt (ashift (xor x 1) C) C) where C is
3845 the bitsize of the mode - 1. This allows simplification of
3846 "a = (b & 8) == 0;" */
3847 if (XEXP (x
, 1) == constm1_rtx
3848 && GET_CODE (XEXP (x
, 0)) != REG
3849 && ! (GET_CODE (XEXP (x
,0)) == SUBREG
3850 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == REG
)
3851 && nonzero_bits (XEXP (x
, 0), mode
) == 1)
3852 return simplify_shift_const (NULL_RTX
, ASHIFTRT
, mode
,
3853 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
3854 gen_rtx_combine (XOR
, mode
,
3855 XEXP (x
, 0), const1_rtx
),
3856 GET_MODE_BITSIZE (mode
) - 1),
3857 GET_MODE_BITSIZE (mode
) - 1);
3859 /* If we are adding two things that have no bits in common, convert
3860 the addition into an IOR. This will often be further simplified,
3861 for example in cases like ((a & 1) + (a & 2)), which can
3864 if (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
3865 && (nonzero_bits (XEXP (x
, 0), mode
)
3866 & nonzero_bits (XEXP (x
, 1), mode
)) == 0)
3867 return gen_binary (IOR
, mode
, XEXP (x
, 0), XEXP (x
, 1));
3871 /* If STORE_FLAG_VALUE is 1, (minus 1 (comparison foo bar)) can be done
3872 by reversing the comparison code if valid. */
3873 if (STORE_FLAG_VALUE
== 1
3874 && XEXP (x
, 0) == const1_rtx
3875 && GET_RTX_CLASS (GET_CODE (XEXP (x
, 1))) == '<'
3876 && reversible_comparison_p (XEXP (x
, 1)))
3877 return gen_binary (reverse_condition (GET_CODE (XEXP (x
, 1))),
3878 mode
, XEXP (XEXP (x
, 1), 0),
3879 XEXP (XEXP (x
, 1), 1));
3881 /* (minus <foo> (and <foo> (const_int -pow2))) becomes
3882 (and <foo> (const_int pow2-1)) */
3883 if (GET_CODE (XEXP (x
, 1)) == AND
3884 && GET_CODE (XEXP (XEXP (x
, 1), 1)) == CONST_INT
3885 && exact_log2 (- INTVAL (XEXP (XEXP (x
, 1), 1))) >= 0
3886 && rtx_equal_p (XEXP (XEXP (x
, 1), 0), XEXP (x
, 0)))
3887 return simplify_and_const_int (NULL_RTX
, mode
, XEXP (x
, 0),
3888 - INTVAL (XEXP (XEXP (x
, 1), 1)) - 1);
3890 /* Canonicalize (minus A (plus B C)) to (minus (minus A B) C) for
3892 if (GET_CODE (XEXP (x
, 1)) == PLUS
&& INTEGRAL_MODE_P (mode
))
3893 return gen_binary (MINUS
, mode
,
3894 gen_binary (MINUS
, mode
, XEXP (x
, 0),
3895 XEXP (XEXP (x
, 1), 0)),
3896 XEXP (XEXP (x
, 1), 1));
3900 /* If we have (mult (plus A B) C), apply the distributive law and then
3901 the inverse distributive law to see if things simplify. This
3902 occurs mostly in addresses, often when unrolling loops. */
3904 if (GET_CODE (XEXP (x
, 0)) == PLUS
)
3906 x
= apply_distributive_law
3907 (gen_binary (PLUS
, mode
,
3908 gen_binary (MULT
, mode
,
3909 XEXP (XEXP (x
, 0), 0), XEXP (x
, 1)),
3910 gen_binary (MULT
, mode
,
3911 XEXP (XEXP (x
, 0), 1), XEXP (x
, 1))));
3913 if (GET_CODE (x
) != MULT
)
3919 /* If this is a divide by a power of two, treat it as a shift if
3920 its first operand is a shift. */
3921 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
3922 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)))) >= 0
3923 && (GET_CODE (XEXP (x
, 0)) == ASHIFT
3924 || GET_CODE (XEXP (x
, 0)) == LSHIFTRT
3925 || GET_CODE (XEXP (x
, 0)) == ASHIFTRT
3926 || GET_CODE (XEXP (x
, 0)) == ROTATE
3927 || GET_CODE (XEXP (x
, 0)) == ROTATERT
))
3928 return simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
, XEXP (x
, 0), i
);
3932 case GT
: case GTU
: case GE
: case GEU
:
3933 case LT
: case LTU
: case LE
: case LEU
:
3934 /* If the first operand is a condition code, we can't do anything
3936 if (GET_CODE (XEXP (x
, 0)) == COMPARE
3937 || (GET_MODE_CLASS (GET_MODE (XEXP (x
, 0))) != MODE_CC
3939 && XEXP (x
, 0) != cc0_rtx
3943 rtx op0
= XEXP (x
, 0);
3944 rtx op1
= XEXP (x
, 1);
3945 enum rtx_code new_code
;
3947 if (GET_CODE (op0
) == COMPARE
)
3948 op1
= XEXP (op0
, 1), op0
= XEXP (op0
, 0);
3950 /* Simplify our comparison, if possible. */
3951 new_code
= simplify_comparison (code
, &op0
, &op1
);
3953 /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X
3954 if only the low-order bit is possibly nonzero in X (such as when
3955 X is a ZERO_EXTRACT of one bit). Similarly, we can convert EQ to
3956 (xor X 1) or (minus 1 X); we use the former. Finally, if X is
3957 known to be either 0 or -1, NE becomes a NEG and EQ becomes
3960 Remove any ZERO_EXTRACT we made when thinking this was a
3961 comparison. It may now be simpler to use, e.g., an AND. If a
3962 ZERO_EXTRACT is indeed appropriate, it will be placed back by
3963 the call to make_compound_operation in the SET case. */
3965 if (STORE_FLAG_VALUE
== 1
3966 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
3967 && op1
== const0_rtx
&& nonzero_bits (op0
, mode
) == 1)
3968 return gen_lowpart_for_combine (mode
,
3969 expand_compound_operation (op0
));
3971 else if (STORE_FLAG_VALUE
== 1
3972 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
3973 && op1
== const0_rtx
3974 && (num_sign_bit_copies (op0
, mode
)
3975 == GET_MODE_BITSIZE (mode
)))
3977 op0
= expand_compound_operation (op0
);
3978 return gen_unary (NEG
, mode
, mode
,
3979 gen_lowpart_for_combine (mode
, op0
));
3982 else if (STORE_FLAG_VALUE
== 1
3983 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
3984 && op1
== const0_rtx
3985 && nonzero_bits (op0
, mode
) == 1)
3987 op0
= expand_compound_operation (op0
);
3988 return gen_binary (XOR
, mode
,
3989 gen_lowpart_for_combine (mode
, op0
),
3993 else if (STORE_FLAG_VALUE
== 1
3994 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
3995 && op1
== const0_rtx
3996 && (num_sign_bit_copies (op0
, mode
)
3997 == GET_MODE_BITSIZE (mode
)))
3999 op0
= expand_compound_operation (op0
);
4000 return plus_constant (gen_lowpart_for_combine (mode
, op0
), 1);
4003 /* If STORE_FLAG_VALUE is -1, we have cases similar to
4005 if (STORE_FLAG_VALUE
== -1
4006 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
4007 && op1
== const0_rtx
4008 && (num_sign_bit_copies (op0
, mode
)
4009 == GET_MODE_BITSIZE (mode
)))
4010 return gen_lowpart_for_combine (mode
,
4011 expand_compound_operation (op0
));
4013 else if (STORE_FLAG_VALUE
== -1
4014 && new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
4015 && op1
== const0_rtx
4016 && nonzero_bits (op0
, mode
) == 1)
4018 op0
= expand_compound_operation (op0
);
4019 return gen_unary (NEG
, mode
, mode
,
4020 gen_lowpart_for_combine (mode
, op0
));
4023 else if (STORE_FLAG_VALUE
== -1
4024 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
4025 && op1
== const0_rtx
4026 && (num_sign_bit_copies (op0
, mode
)
4027 == GET_MODE_BITSIZE (mode
)))
4029 op0
= expand_compound_operation (op0
);
4030 return gen_unary (NOT
, mode
, mode
,
4031 gen_lowpart_for_combine (mode
, op0
));
4034 /* If X is 0/1, (eq X 0) is X-1. */
4035 else if (STORE_FLAG_VALUE
== -1
4036 && new_code
== EQ
&& GET_MODE_CLASS (mode
) == MODE_INT
4037 && op1
== const0_rtx
4038 && nonzero_bits (op0
, mode
) == 1)
4040 op0
= expand_compound_operation (op0
);
4041 return plus_constant (gen_lowpart_for_combine (mode
, op0
), -1);
4044 /* If STORE_FLAG_VALUE says to just test the sign bit and X has just
4045 one bit that might be nonzero, we can convert (ne x 0) to
4046 (ashift x c) where C puts the bit in the sign bit. Remove any
4047 AND with STORE_FLAG_VALUE when we are done, since we are only
4048 going to test the sign bit. */
4049 if (new_code
== NE
&& GET_MODE_CLASS (mode
) == MODE_INT
4050 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
4051 && ((STORE_FLAG_VALUE
& GET_MODE_MASK (mode
))
4052 == (HOST_WIDE_INT
) 1 << (GET_MODE_BITSIZE (mode
) - 1))
4053 && op1
== const0_rtx
4054 && mode
== GET_MODE (op0
)
4055 && (i
= exact_log2 (nonzero_bits (op0
, mode
))) >= 0)
4057 x
= simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
4058 expand_compound_operation (op0
),
4059 GET_MODE_BITSIZE (mode
) - 1 - i
);
4060 if (GET_CODE (x
) == AND
&& XEXP (x
, 1) == const_true_rtx
)
4066 /* If the code changed, return a whole new comparison. */
4067 if (new_code
!= code
)
4068 return gen_rtx_combine (new_code
, mode
, op0
, op1
);
4070 /* Otherwise, keep this operation, but maybe change its operands.
4071 This also converts (ne (compare FOO BAR) 0) to (ne FOO BAR). */
4072 SUBST (XEXP (x
, 0), op0
);
4073 SUBST (XEXP (x
, 1), op1
);
4078 return simplify_if_then_else (x
);
4084 /* If we are processing SET_DEST, we are done. */
4088 return expand_compound_operation (x
);
4091 return simplify_set (x
);
4096 return simplify_logical (x
, last
);
4099 /* (abs (neg <foo>)) -> (abs <foo>) */
4100 if (GET_CODE (XEXP (x
, 0)) == NEG
)
4101 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
4103 /* If the mode of the operand is VOIDmode (i.e. if it is ASM_OPERANDS),
4105 if (GET_MODE (XEXP (x
, 0)) == VOIDmode
)
4108 /* If operand is something known to be positive, ignore the ABS. */
4109 if (GET_CODE (XEXP (x
, 0)) == FFS
|| GET_CODE (XEXP (x
, 0)) == ABS
4110 || ((GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
4111 <= HOST_BITS_PER_WIDE_INT
)
4112 && ((nonzero_bits (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
4113 & ((HOST_WIDE_INT
) 1
4114 << (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))) - 1)))
4119 /* If operand is known to be only -1 or 0, convert ABS to NEG. */
4120 if (num_sign_bit_copies (XEXP (x
, 0), mode
) == GET_MODE_BITSIZE (mode
))
4121 return gen_rtx_combine (NEG
, mode
, XEXP (x
, 0));
4126 /* (ffs (*_extend <X>)) = (ffs <X>) */
4127 if (GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
4128 || GET_CODE (XEXP (x
, 0)) == ZERO_EXTEND
)
4129 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
4133 /* (float (sign_extend <X>)) = (float <X>). */
4134 if (GET_CODE (XEXP (x
, 0)) == SIGN_EXTEND
)
4135 SUBST (XEXP (x
, 0), XEXP (XEXP (x
, 0), 0));
4143 /* If this is a shift by a constant amount, simplify it. */
4144 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
4145 return simplify_shift_const (x
, code
, mode
, XEXP (x
, 0),
4146 INTVAL (XEXP (x
, 1)));
4148 #ifdef SHIFT_COUNT_TRUNCATED
4149 else if (SHIFT_COUNT_TRUNCATED
&& GET_CODE (XEXP (x
, 1)) != REG
)
4151 force_to_mode (XEXP (x
, 1), GET_MODE (x
),
4153 << exact_log2 (GET_MODE_BITSIZE (GET_MODE (x
))))
4167 /* Simplify X, an IF_THEN_ELSE expression. Return the new expression. */
4170 simplify_if_then_else (x
)
4173 enum machine_mode mode
= GET_MODE (x
);
4174 rtx cond
= XEXP (x
, 0);
4175 rtx
true = XEXP (x
, 1);
4176 rtx
false = XEXP (x
, 2);
4177 enum rtx_code true_code
= GET_CODE (cond
);
4178 int comparison_p
= GET_RTX_CLASS (true_code
) == '<';
4182 /* Simplify storing of the truth value. */
4183 if (comparison_p
&& true == const_true_rtx
&& false == const0_rtx
)
4184 return gen_binary (true_code
, mode
, XEXP (cond
, 0), XEXP (cond
, 1));
4186 /* Also when the truth value has to be reversed. */
4187 if (comparison_p
&& reversible_comparison_p (cond
)
4188 && true == const0_rtx
&& false == const_true_rtx
)
4189 return gen_binary (reverse_condition (true_code
),
4190 mode
, XEXP (cond
, 0), XEXP (cond
, 1));
4192 /* Sometimes we can simplify the arm of an IF_THEN_ELSE if a register used
4193 in it is being compared against certain values. Get the true and false
4194 comparisons and see if that says anything about the value of each arm. */
4196 if (comparison_p
&& reversible_comparison_p (cond
)
4197 && GET_CODE (XEXP (cond
, 0)) == REG
)
4200 rtx from
= XEXP (cond
, 0);
4201 enum rtx_code false_code
= reverse_condition (true_code
);
4202 rtx true_val
= XEXP (cond
, 1);
4203 rtx false_val
= true_val
;
4206 /* If FALSE_CODE is EQ, swap the codes and arms. */
4208 if (false_code
== EQ
)
4210 swapped
= 1, true_code
= EQ
, false_code
= NE
;
4211 temp
= true, true = false, false = temp
;
4214 /* If we are comparing against zero and the expression being tested has
4215 only a single bit that might be nonzero, that is its value when it is
4216 not equal to zero. Similarly if it is known to be -1 or 0. */
4218 if (true_code
== EQ
&& true_val
== const0_rtx
4219 && exact_log2 (nzb
= nonzero_bits (from
, GET_MODE (from
))) >= 0)
4220 false_code
= EQ
, false_val
= GEN_INT (nzb
);
4221 else if (true_code
== EQ
&& true_val
== const0_rtx
4222 && (num_sign_bit_copies (from
, GET_MODE (from
))
4223 == GET_MODE_BITSIZE (GET_MODE (from
))))
4224 false_code
= EQ
, false_val
= constm1_rtx
;
4226 /* Now simplify an arm if we know the value of the register in the
4227 branch and it is used in the arm. Be careful due to the potential
4228 of locally-shared RTL. */
4230 if (reg_mentioned_p (from
, true))
4231 true = subst (known_cond (copy_rtx (true), true_code
, from
, true_val
),
4232 pc_rtx
, pc_rtx
, 0, 0);
4233 if (reg_mentioned_p (from
, false))
4234 false = subst (known_cond (copy_rtx (false), false_code
,
4236 pc_rtx
, pc_rtx
, 0, 0);
4238 SUBST (XEXP (x
, 1), swapped
? false : true);
4239 SUBST (XEXP (x
, 2), swapped
? true : false);
4241 true = XEXP (x
, 1), false = XEXP (x
, 2), true_code
= GET_CODE (cond
);
4244 /* If we have (if_then_else FOO (pc) (label_ref BAR)) and FOO can be
4245 reversed, do so to avoid needing two sets of patterns for
4246 subtract-and-branch insns. Similarly if we have a constant in the true
4247 arm, the false arm is the same as the first operand of the comparison, or
4248 the false arm is more complicated than the true arm. */
4250 if (comparison_p
&& reversible_comparison_p (cond
)
4252 || (CONSTANT_P (true)
4253 && GET_CODE (false) != CONST_INT
&& false != pc_rtx
)
4254 || true == const0_rtx
4255 || (GET_RTX_CLASS (GET_CODE (true)) == 'o'
4256 && GET_RTX_CLASS (GET_CODE (false)) != 'o')
4257 || (GET_CODE (true) == SUBREG
4258 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (true))) == 'o'
4259 && GET_RTX_CLASS (GET_CODE (false)) != 'o')
4260 || reg_mentioned_p (true, false)
4261 || rtx_equal_p (false, XEXP (cond
, 0))))
4263 true_code
= reverse_condition (true_code
);
4265 gen_binary (true_code
, GET_MODE (cond
), XEXP (cond
, 0),
4268 SUBST (XEXP (x
, 1), false);
4269 SUBST (XEXP (x
, 2), true);
4271 temp
= true, true = false, false = temp
, cond
= XEXP (x
, 0);
4273 /* It is possible that the conditional has been simplified out. */
4274 true_code
= GET_CODE (cond
);
4275 comparison_p
= GET_RTX_CLASS (true_code
) == '<';
4278 /* If the two arms are identical, we don't need the comparison. */
4280 if (rtx_equal_p (true, false) && ! side_effects_p (cond
))
4283 /* Convert a == b ? b : a to "a". */
4284 if (true_code
== EQ
&& ! side_effects_p (cond
)
4285 && rtx_equal_p (XEXP (cond
, 0), false)
4286 && rtx_equal_p (XEXP (cond
, 1), true))
4288 else if (true_code
== NE
&& ! side_effects_p (cond
)
4289 && rtx_equal_p (XEXP (cond
, 0), true)
4290 && rtx_equal_p (XEXP (cond
, 1), false))
4293 /* Look for cases where we have (abs x) or (neg (abs X)). */
4295 if (GET_MODE_CLASS (mode
) == MODE_INT
4296 && GET_CODE (false) == NEG
4297 && rtx_equal_p (true, XEXP (false, 0))
4299 && rtx_equal_p (true, XEXP (cond
, 0))
4300 && ! side_effects_p (true))
4305 return gen_unary (ABS
, mode
, mode
, true);
4308 return gen_unary (NEG
, mode
, mode
, gen_unary (ABS
, mode
, mode
, true));
4313 /* Look for MIN or MAX. */
4315 if ((! FLOAT_MODE_P (mode
) || flag_fast_math
)
4317 && rtx_equal_p (XEXP (cond
, 0), true)
4318 && rtx_equal_p (XEXP (cond
, 1), false)
4319 && ! side_effects_p (cond
))
4324 return gen_binary (SMAX
, mode
, true, false);
4327 return gen_binary (SMIN
, mode
, true, false);
4330 return gen_binary (UMAX
, mode
, true, false);
4333 return gen_binary (UMIN
, mode
, true, false);
4338 /* If we have (if_then_else COND (OP Z C1) Z) and OP is an identity when its
4339 second operand is zero, this can be done as (OP Z (mult COND C2)) where
4340 C2 = C1 * STORE_FLAG_VALUE. Similarly if OP has an outer ZERO_EXTEND or
4341 SIGN_EXTEND as long as Z is already extended (so we don't destroy it).
4342 We can do this kind of thing in some cases when STORE_FLAG_VALUE is
4343 neither 1 or -1, but it isn't worth checking for. */
4345 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
4346 && comparison_p
&& mode
!= VOIDmode
&& ! side_effects_p (x
))
4348 rtx t
= make_compound_operation (true, SET
);
4349 rtx f
= make_compound_operation (false, SET
);
4350 rtx cond_op0
= XEXP (cond
, 0);
4351 rtx cond_op1
= XEXP (cond
, 1);
4352 enum rtx_code op
, extend_op
= NIL
;
4353 enum machine_mode m
= mode
;
4356 if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == MINUS
4357 || GET_CODE (t
) == IOR
|| GET_CODE (t
) == XOR
4358 || GET_CODE (t
) == ASHIFT
4359 || GET_CODE (t
) == LSHIFTRT
|| GET_CODE (t
) == ASHIFTRT
)
4360 && rtx_equal_p (XEXP (t
, 0), f
))
4361 c1
= XEXP (t
, 1), op
= GET_CODE (t
), z
= f
;
4363 /* If an identity-zero op is commutative, check whether there
4364 would be a match if we swapped the operands. */
4365 else if ((GET_CODE (t
) == PLUS
|| GET_CODE (t
) == IOR
4366 || GET_CODE (t
) == XOR
)
4367 && rtx_equal_p (XEXP (t
, 1), f
))
4368 c1
= XEXP (t
, 0), op
= GET_CODE (t
), z
= f
;
4369 else if (GET_CODE (t
) == SIGN_EXTEND
4370 && (GET_CODE (XEXP (t
, 0)) == PLUS
4371 || GET_CODE (XEXP (t
, 0)) == MINUS
4372 || GET_CODE (XEXP (t
, 0)) == IOR
4373 || GET_CODE (XEXP (t
, 0)) == XOR
4374 || GET_CODE (XEXP (t
, 0)) == ASHIFT
4375 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
4376 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
4377 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
4378 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
4379 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
4380 && (num_sign_bit_copies (f
, GET_MODE (f
))
4381 > (GET_MODE_BITSIZE (mode
)
4382 - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t
, 0), 0))))))
4384 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
4385 extend_op
= SIGN_EXTEND
;
4386 m
= GET_MODE (XEXP (t
, 0));
4388 else if (GET_CODE (t
) == SIGN_EXTEND
4389 && (GET_CODE (XEXP (t
, 0)) == PLUS
4390 || GET_CODE (XEXP (t
, 0)) == IOR
4391 || GET_CODE (XEXP (t
, 0)) == XOR
)
4392 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
4393 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
4394 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
4395 && (num_sign_bit_copies (f
, GET_MODE (f
))
4396 > (GET_MODE_BITSIZE (mode
)
4397 - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t
, 0), 1))))))
4399 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
4400 extend_op
= SIGN_EXTEND
;
4401 m
= GET_MODE (XEXP (t
, 0));
4403 else if (GET_CODE (t
) == ZERO_EXTEND
4404 && (GET_CODE (XEXP (t
, 0)) == PLUS
4405 || GET_CODE (XEXP (t
, 0)) == MINUS
4406 || GET_CODE (XEXP (t
, 0)) == IOR
4407 || GET_CODE (XEXP (t
, 0)) == XOR
4408 || GET_CODE (XEXP (t
, 0)) == ASHIFT
4409 || GET_CODE (XEXP (t
, 0)) == LSHIFTRT
4410 || GET_CODE (XEXP (t
, 0)) == ASHIFTRT
)
4411 && GET_CODE (XEXP (XEXP (t
, 0), 0)) == SUBREG
4412 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
4413 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 0))
4414 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 0)), f
)
4415 && ((nonzero_bits (f
, GET_MODE (f
))
4416 & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 0))))
4419 c1
= XEXP (XEXP (t
, 0), 1); z
= f
; op
= GET_CODE (XEXP (t
, 0));
4420 extend_op
= ZERO_EXTEND
;
4421 m
= GET_MODE (XEXP (t
, 0));
4423 else if (GET_CODE (t
) == ZERO_EXTEND
4424 && (GET_CODE (XEXP (t
, 0)) == PLUS
4425 || GET_CODE (XEXP (t
, 0)) == IOR
4426 || GET_CODE (XEXP (t
, 0)) == XOR
)
4427 && GET_CODE (XEXP (XEXP (t
, 0), 1)) == SUBREG
4428 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
4429 && subreg_lowpart_p (XEXP (XEXP (t
, 0), 1))
4430 && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t
, 0), 1)), f
)
4431 && ((nonzero_bits (f
, GET_MODE (f
))
4432 & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t
, 0), 1))))
4435 c1
= XEXP (XEXP (t
, 0), 0); z
= f
; op
= GET_CODE (XEXP (t
, 0));
4436 extend_op
= ZERO_EXTEND
;
4437 m
= GET_MODE (XEXP (t
, 0));
4442 temp
= subst (gen_binary (true_code
, m
, cond_op0
, cond_op1
),
4443 pc_rtx
, pc_rtx
, 0, 0);
4444 temp
= gen_binary (MULT
, m
, temp
,
4445 gen_binary (MULT
, m
, c1
, const_true_rtx
));
4446 temp
= subst (temp
, pc_rtx
, pc_rtx
, 0, 0);
4447 temp
= gen_binary (op
, m
, gen_lowpart_for_combine (m
, z
), temp
);
4449 if (extend_op
!= NIL
)
4450 temp
= gen_unary (extend_op
, mode
, m
, temp
);
4456 /* If we have (if_then_else (ne A 0) C1 0) and either A is known to be 0 or
4457 1 and C1 is a single bit or A is known to be 0 or -1 and C1 is the
4458 negation of a single bit, we can convert this operation to a shift. We
4459 can actually do this more generally, but it doesn't seem worth it. */
4461 if (true_code
== NE
&& XEXP (cond
, 1) == const0_rtx
4462 && false == const0_rtx
&& GET_CODE (true) == CONST_INT
4463 && ((1 == nonzero_bits (XEXP (cond
, 0), mode
)
4464 && (i
= exact_log2 (INTVAL (true))) >= 0)
4465 || ((num_sign_bit_copies (XEXP (cond
, 0), mode
)
4466 == GET_MODE_BITSIZE (mode
))
4467 && (i
= exact_log2 (- INTVAL (true))) >= 0)))
4469 simplify_shift_const (NULL_RTX
, ASHIFT
, mode
,
4470 gen_lowpart_for_combine (mode
, XEXP (cond
, 0)), i
);
4475 /* Simplify X, a SET expression. Return the new expression. */
4481 rtx src
= SET_SRC (x
);
4482 rtx dest
= SET_DEST (x
);
4483 enum machine_mode mode
4484 = GET_MODE (src
) != VOIDmode
? GET_MODE (src
) : GET_MODE (dest
);
4488 /* (set (pc) (return)) gets written as (return). */
4489 if (GET_CODE (dest
) == PC
&& GET_CODE (src
) == RETURN
)
4492 /* Now that we know for sure which bits of SRC we are using, see if we can
4493 simplify the expression for the object knowing that we only need the
4496 if (GET_MODE_CLASS (mode
) == MODE_INT
)
4497 src
= force_to_mode (src
, mode
, GET_MODE_MASK (mode
), NULL_RTX
, 0);
4499 /* If we are setting CC0 or if the source is a COMPARE, look for the use of
4500 the comparison result and try to simplify it unless we already have used
4501 undobuf.other_insn. */
4502 if ((GET_CODE (src
) == COMPARE
4507 && (cc_use
= find_single_use (dest
, subst_insn
, &other_insn
)) != 0
4508 && (undobuf
.other_insn
== 0 || other_insn
== undobuf
.other_insn
)
4509 && GET_RTX_CLASS (GET_CODE (*cc_use
)) == '<'
4510 && rtx_equal_p (XEXP (*cc_use
, 0), dest
))
4512 enum rtx_code old_code
= GET_CODE (*cc_use
);
4513 enum rtx_code new_code
;
4515 int other_changed
= 0;
4516 enum machine_mode compare_mode
= GET_MODE (dest
);
4518 if (GET_CODE (src
) == COMPARE
)
4519 op0
= XEXP (src
, 0), op1
= XEXP (src
, 1);
4521 op0
= src
, op1
= const0_rtx
;
4523 /* Simplify our comparison, if possible. */
4524 new_code
= simplify_comparison (old_code
, &op0
, &op1
);
4526 #ifdef EXTRA_CC_MODES
4527 /* If this machine has CC modes other than CCmode, check to see if we
4528 need to use a different CC mode here. */
4529 compare_mode
= SELECT_CC_MODE (new_code
, op0
, op1
);
4530 #endif /* EXTRA_CC_MODES */
4532 #if !defined (HAVE_cc0) && defined (EXTRA_CC_MODES)
4533 /* If the mode changed, we have to change SET_DEST, the mode in the
4534 compare, and the mode in the place SET_DEST is used. If SET_DEST is
4535 a hard register, just build new versions with the proper mode. If it
4536 is a pseudo, we lose unless it is only time we set the pseudo, in
4537 which case we can safely change its mode. */
4538 if (compare_mode
!= GET_MODE (dest
))
4540 int regno
= REGNO (dest
);
4541 rtx new_dest
= gen_rtx (REG
, compare_mode
, regno
);
4543 if (regno
< FIRST_PSEUDO_REGISTER
4544 || (REG_N_SETS (regno
) == 1 && ! REG_USERVAR_P (dest
)))
4546 if (regno
>= FIRST_PSEUDO_REGISTER
)
4547 SUBST (regno_reg_rtx
[regno
], new_dest
);
4549 SUBST (SET_DEST (x
), new_dest
);
4550 SUBST (XEXP (*cc_use
, 0), new_dest
);
4558 /* If the code changed, we have to build a new comparison in
4559 undobuf.other_insn. */
4560 if (new_code
!= old_code
)
4562 unsigned HOST_WIDE_INT mask
;
4564 SUBST (*cc_use
, gen_rtx_combine (new_code
, GET_MODE (*cc_use
),
4567 /* If the only change we made was to change an EQ into an NE or
4568 vice versa, OP0 has only one bit that might be nonzero, and OP1
4569 is zero, check if changing the user of the condition code will
4570 produce a valid insn. If it won't, we can keep the original code
4571 in that insn by surrounding our operation with an XOR. */
4573 if (((old_code
== NE
&& new_code
== EQ
)
4574 || (old_code
== EQ
&& new_code
== NE
))
4575 && ! other_changed
&& op1
== const0_rtx
4576 && GET_MODE_BITSIZE (GET_MODE (op0
)) <= HOST_BITS_PER_WIDE_INT
4577 && exact_log2 (mask
= nonzero_bits (op0
, GET_MODE (op0
))) >= 0)
4579 rtx pat
= PATTERN (other_insn
), note
= 0;
4582 if ((recog_for_combine (&pat
, other_insn
, ¬e
, &scratches
) < 0
4583 && ! check_asm_operands (pat
)))
4585 PUT_CODE (*cc_use
, old_code
);
4588 op0
= gen_binary (XOR
, GET_MODE (op0
), op0
, GEN_INT (mask
));
4596 undobuf
.other_insn
= other_insn
;
4599 /* If we are now comparing against zero, change our source if
4600 needed. If we do not use cc0, we always have a COMPARE. */
4601 if (op1
== const0_rtx
&& dest
== cc0_rtx
)
4603 SUBST (SET_SRC (x
), op0
);
4609 /* Otherwise, if we didn't previously have a COMPARE in the
4610 correct mode, we need one. */
4611 if (GET_CODE (src
) != COMPARE
|| GET_MODE (src
) != compare_mode
)
4614 gen_rtx_combine (COMPARE
, compare_mode
, op0
, op1
));
4619 /* Otherwise, update the COMPARE if needed. */
4620 SUBST (XEXP (src
, 0), op0
);
4621 SUBST (XEXP (src
, 1), op1
);
4626 /* Get SET_SRC in a form where we have placed back any
4627 compound expressions. Then do the checks below. */
4628 src
= make_compound_operation (src
, SET
);
4629 SUBST (SET_SRC (x
), src
);
4632 /* If we have (set x (subreg:m1 (op:m2 ...) 0)) with OP being some operation,
4633 and X being a REG or (subreg (reg)), we may be able to convert this to
4634 (set (subreg:m2 x) (op)).
4636 We can always do this if M1 is narrower than M2 because that means that
4637 we only care about the low bits of the result.
4639 However, on machines without WORD_REGISTER_OPERATIONS defined, we cannot
4640 perform a narrower operation that requested since the high-order bits will
4641 be undefined. On machine where it is defined, this transformation is safe
4642 as long as M1 and M2 have the same number of words. */
4644 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
)
4645 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (src
))) != 'o'
4646 && (((GET_MODE_SIZE (GET_MODE (src
)) + (UNITS_PER_WORD
- 1))
4648 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))
4649 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
))
4650 #ifndef WORD_REGISTER_OPERATIONS
4651 && (GET_MODE_SIZE (GET_MODE (src
))
4652 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
))))
4654 #ifdef CLASS_CANNOT_CHANGE_SIZE
4655 && ! (GET_CODE (dest
) == REG
&& REGNO (dest
) < FIRST_PSEUDO_REGISTER
4656 && (TEST_HARD_REG_BIT
4657 (reg_class_contents
[(int) CLASS_CANNOT_CHANGE_SIZE
],
4659 && (GET_MODE_SIZE (GET_MODE (src
))
4660 != GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
)))))
4662 && (GET_CODE (dest
) == REG
4663 || (GET_CODE (dest
) == SUBREG
4664 && GET_CODE (SUBREG_REG (dest
)) == REG
)))
4666 SUBST (SET_DEST (x
),
4667 gen_lowpart_for_combine (GET_MODE (SUBREG_REG (src
)),
4669 SUBST (SET_SRC (x
), SUBREG_REG (src
));
4671 src
= SET_SRC (x
), dest
= SET_DEST (x
);
4674 #ifdef LOAD_EXTEND_OP
4675 /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with M wider than N, this
4676 would require a paradoxical subreg. Replace the subreg with a
4677 zero_extend to avoid the reload that would otherwise be required. */
4679 if (GET_CODE (src
) == SUBREG
&& subreg_lowpart_p (src
)
4680 && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src
))) != NIL
4681 && SUBREG_WORD (src
) == 0
4682 && (GET_MODE_SIZE (GET_MODE (src
))
4683 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src
))))
4684 && GET_CODE (SUBREG_REG (src
)) == MEM
)
4687 gen_rtx_combine (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src
))),
4688 GET_MODE (src
), XEXP (src
, 0)));
4694 /* If we don't have a conditional move, SET_SRC is an IF_THEN_ELSE, and we
4695 are comparing an item known to be 0 or -1 against 0, use a logical
4696 operation instead. Check for one of the arms being an IOR of the other
4697 arm with some value. We compute three terms to be IOR'ed together. In
4698 practice, at most two will be nonzero. Then we do the IOR's. */
4700 if (GET_CODE (dest
) != PC
4701 && GET_CODE (src
) == IF_THEN_ELSE
4702 && GET_MODE_CLASS (GET_MODE (src
)) == MODE_INT
4703 && (GET_CODE (XEXP (src
, 0)) == EQ
|| GET_CODE (XEXP (src
, 0)) == NE
)
4704 && XEXP (XEXP (src
, 0), 1) == const0_rtx
4705 && GET_MODE (src
) == GET_MODE (XEXP (XEXP (src
, 0), 0))
4706 #ifdef HAVE_conditional_move
4707 && ! can_conditionally_move_p (GET_MODE (src
))
4709 && (num_sign_bit_copies (XEXP (XEXP (src
, 0), 0),
4710 GET_MODE (XEXP (XEXP (src
, 0), 0)))
4711 == GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (src
, 0), 0))))
4712 && ! side_effects_p (src
))
4714 rtx
true = (GET_CODE (XEXP (src
, 0)) == NE
4715 ? XEXP (src
, 1) : XEXP (src
, 2));
4716 rtx
false = (GET_CODE (XEXP (src
, 0)) == NE
4717 ? XEXP (src
, 2) : XEXP (src
, 1));
4718 rtx term1
= const0_rtx
, term2
, term3
;
4720 if (GET_CODE (true) == IOR
&& rtx_equal_p (XEXP (true, 0), false))
4721 term1
= false, true = XEXP (true, 1), false = const0_rtx
;
4722 else if (GET_CODE (true) == IOR
4723 && rtx_equal_p (XEXP (true, 1), false))
4724 term1
= false, true = XEXP (true, 0), false = const0_rtx
;
4725 else if (GET_CODE (false) == IOR
4726 && rtx_equal_p (XEXP (false, 0), true))
4727 term1
= true, false = XEXP (false, 1), true = const0_rtx
;
4728 else if (GET_CODE (false) == IOR
4729 && rtx_equal_p (XEXP (false, 1), true))
4730 term1
= true, false = XEXP (false, 0), true = const0_rtx
;
4732 term2
= gen_binary (AND
, GET_MODE (src
), XEXP (XEXP (src
, 0), 0), true);
4733 term3
= gen_binary (AND
, GET_MODE (src
),
4734 gen_unary (NOT
, GET_MODE (src
), GET_MODE (src
),
4735 XEXP (XEXP (src
, 0), 0)),
4739 gen_binary (IOR
, GET_MODE (src
),
4740 gen_binary (IOR
, GET_MODE (src
), term1
, term2
),
4746 /* If either SRC or DEST is a CLOBBER of (const_int 0), make this
4747 whole thing fail. */
4748 if (GET_CODE (src
) == CLOBBER
&& XEXP (src
, 0) == const0_rtx
)
4750 else if (GET_CODE (dest
) == CLOBBER
&& XEXP (dest
, 0) == const0_rtx
)
4753 /* Convert this into a field assignment operation, if possible. */
4754 return make_field_assignment (x
);
4757 /* Simplify, X, and AND, IOR, or XOR operation, and return the simplified
4758 result. LAST is nonzero if this is the last retry. */
4761 simplify_logical (x
, last
)
4765 enum machine_mode mode
= GET_MODE (x
);
4766 rtx op0
= XEXP (x
, 0);
4767 rtx op1
= XEXP (x
, 1);
4769 switch (GET_CODE (x
))
4772 /* Convert (A ^ B) & A to A & (~ B) since the latter is often a single
4773 insn (and may simplify more). */
4774 if (GET_CODE (op0
) == XOR
4775 && rtx_equal_p (XEXP (op0
, 0), op1
)
4776 && ! side_effects_p (op1
))
4777 x
= gen_binary (AND
, mode
,
4778 gen_unary (NOT
, mode
, mode
, XEXP (op0
, 1)), op1
);
4780 if (GET_CODE (op0
) == XOR
4781 && rtx_equal_p (XEXP (op0
, 1), op1
)
4782 && ! side_effects_p (op1
))
4783 x
= gen_binary (AND
, mode
,
4784 gen_unary (NOT
, mode
, mode
, XEXP (op0
, 0)), op1
);
4786 /* Similarly for (~ (A ^ B)) & A. */
4787 if (GET_CODE (op0
) == NOT
4788 && GET_CODE (XEXP (op0
, 0)) == XOR
4789 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), op1
)
4790 && ! side_effects_p (op1
))
4791 x
= gen_binary (AND
, mode
, XEXP (XEXP (op0
, 0), 1), op1
);
4793 if (GET_CODE (op0
) == NOT
4794 && GET_CODE (XEXP (op0
, 0)) == XOR
4795 && rtx_equal_p (XEXP (XEXP (op0
, 0), 1), op1
)
4796 && ! side_effects_p (op1
))
4797 x
= gen_binary (AND
, mode
, XEXP (XEXP (op0
, 0), 0), op1
);
4799 if (GET_CODE (op1
) == CONST_INT
)
4801 x
= simplify_and_const_int (x
, mode
, op0
, INTVAL (op1
));
4803 /* If we have (ior (and (X C1) C2)) and the next restart would be
4804 the last, simplify this by making C1 as small as possible
4807 && GET_CODE (x
) == IOR
&& GET_CODE (op0
) == AND
4808 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
4809 && GET_CODE (op1
) == CONST_INT
)
4810 return gen_binary (IOR
, mode
,
4811 gen_binary (AND
, mode
, XEXP (op0
, 0),
4812 GEN_INT (INTVAL (XEXP (op0
, 1))
4813 & ~ INTVAL (op1
))), op1
);
4815 if (GET_CODE (x
) != AND
)
4818 if (GET_RTX_CLASS (GET_CODE (x
)) == 'c'
4819 || GET_RTX_CLASS (GET_CODE (x
)) == '2')
4820 op0
= XEXP (x
, 0), op1
= XEXP (x
, 1);
4823 /* Convert (A | B) & A to A. */
4824 if (GET_CODE (op0
) == IOR
4825 && (rtx_equal_p (XEXP (op0
, 0), op1
)
4826 || rtx_equal_p (XEXP (op0
, 1), op1
))
4827 && ! side_effects_p (XEXP (op0
, 0))
4828 && ! side_effects_p (XEXP (op0
, 1)))
4831 /* In the following group of tests (and those in case IOR below),
4832 we start with some combination of logical operations and apply
4833 the distributive law followed by the inverse distributive law.
4834 Most of the time, this results in no change. However, if some of
4835 the operands are the same or inverses of each other, simplifications
4838 For example, (and (ior A B) (not B)) can occur as the result of
4839 expanding a bit field assignment. When we apply the distributive
4840 law to this, we get (ior (and (A (not B))) (and (B (not B)))),
4841 which then simplifies to (and (A (not B))).
4843 If we have (and (ior A B) C), apply the distributive law and then
4844 the inverse distributive law to see if things simplify. */
4846 if (GET_CODE (op0
) == IOR
|| GET_CODE (op0
) == XOR
)
4848 x
= apply_distributive_law
4849 (gen_binary (GET_CODE (op0
), mode
,
4850 gen_binary (AND
, mode
, XEXP (op0
, 0), op1
),
4851 gen_binary (AND
, mode
, XEXP (op0
, 1), op1
)));
4852 if (GET_CODE (x
) != AND
)
4856 if (GET_CODE (op1
) == IOR
|| GET_CODE (op1
) == XOR
)
4857 return apply_distributive_law
4858 (gen_binary (GET_CODE (op1
), mode
,
4859 gen_binary (AND
, mode
, XEXP (op1
, 0), op0
),
4860 gen_binary (AND
, mode
, XEXP (op1
, 1), op0
)));
4862 /* Similarly, taking advantage of the fact that
4863 (and (not A) (xor B C)) == (xor (ior A B) (ior A C)) */
4865 if (GET_CODE (op0
) == NOT
&& GET_CODE (op1
) == XOR
)
4866 return apply_distributive_law
4867 (gen_binary (XOR
, mode
,
4868 gen_binary (IOR
, mode
, XEXP (op0
, 0), XEXP (op1
, 0)),
4869 gen_binary (IOR
, mode
, XEXP (op0
, 0), XEXP (op1
, 1))));
4871 else if (GET_CODE (op1
) == NOT
&& GET_CODE (op0
) == XOR
)
4872 return apply_distributive_law
4873 (gen_binary (XOR
, mode
,
4874 gen_binary (IOR
, mode
, XEXP (op1
, 0), XEXP (op0
, 0)),
4875 gen_binary (IOR
, mode
, XEXP (op1
, 0), XEXP (op0
, 1))));
4879 /* (ior A C) is C if all bits of A that might be nonzero are on in C. */
4880 if (GET_CODE (op1
) == CONST_INT
4881 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
4882 && (nonzero_bits (op0
, mode
) & ~ INTVAL (op1
)) == 0)
4885 /* Convert (A & B) | A to A. */
4886 if (GET_CODE (op0
) == AND
4887 && (rtx_equal_p (XEXP (op0
, 0), op1
)
4888 || rtx_equal_p (XEXP (op0
, 1), op1
))
4889 && ! side_effects_p (XEXP (op0
, 0))
4890 && ! side_effects_p (XEXP (op0
, 1)))
4893 /* If we have (ior (and A B) C), apply the distributive law and then
4894 the inverse distributive law to see if things simplify. */
4896 if (GET_CODE (op0
) == AND
)
4898 x
= apply_distributive_law
4899 (gen_binary (AND
, mode
,
4900 gen_binary (IOR
, mode
, XEXP (op0
, 0), op1
),
4901 gen_binary (IOR
, mode
, XEXP (op0
, 1), op1
)));
4903 if (GET_CODE (x
) != IOR
)
4907 if (GET_CODE (op1
) == AND
)
4909 x
= apply_distributive_law
4910 (gen_binary (AND
, mode
,
4911 gen_binary (IOR
, mode
, XEXP (op1
, 0), op0
),
4912 gen_binary (IOR
, mode
, XEXP (op1
, 1), op0
)));
4914 if (GET_CODE (x
) != IOR
)
4918 /* Convert (ior (ashift A CX) (lshiftrt A CY)) where CX+CY equals the
4919 mode size to (rotate A CX). */
4921 if (((GET_CODE (op0
) == ASHIFT
&& GET_CODE (op1
) == LSHIFTRT
)
4922 || (GET_CODE (op1
) == ASHIFT
&& GET_CODE (op0
) == LSHIFTRT
))
4923 && rtx_equal_p (XEXP (op0
, 0), XEXP (op1
, 0))
4924 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
4925 && GET_CODE (XEXP (op1
, 1)) == CONST_INT
4926 && (INTVAL (XEXP (op0
, 1)) + INTVAL (XEXP (op1
, 1))
4927 == GET_MODE_BITSIZE (mode
)))
4928 return gen_rtx (ROTATE
, mode
, XEXP (op0
, 0),
4929 (GET_CODE (op0
) == ASHIFT
4930 ? XEXP (op0
, 1) : XEXP (op1
, 1)));
4932 /* If OP0 is (ashiftrt (plus ...) C), it might actually be
4933 a (sign_extend (plus ...)). If so, OP1 is a CONST_INT, and the PLUS
4934 does not affect any of the bits in OP1, it can really be done
4935 as a PLUS and we can associate. We do this by seeing if OP1
4936 can be safely shifted left C bits. */
4937 if (GET_CODE (op1
) == CONST_INT
&& GET_CODE (op0
) == ASHIFTRT
4938 && GET_CODE (XEXP (op0
, 0)) == PLUS
4939 && GET_CODE (XEXP (XEXP (op0
, 0), 1)) == CONST_INT
4940 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
4941 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
)
4943 int count
= INTVAL (XEXP (op0
, 1));
4944 HOST_WIDE_INT mask
= INTVAL (op1
) << count
;
4946 if (mask
>> count
== INTVAL (op1
)
4947 && (mask
& nonzero_bits (XEXP (op0
, 0), mode
)) == 0)
4949 SUBST (XEXP (XEXP (op0
, 0), 1),
4950 GEN_INT (INTVAL (XEXP (XEXP (op0
, 0), 1)) | mask
));
4957 /* Convert (XOR (NOT x) (NOT y)) to (XOR x y).
4958 Also convert (XOR (NOT x) y) to (NOT (XOR x y)), similarly for
4961 int num_negated
= 0;
4963 if (GET_CODE (op0
) == NOT
)
4964 num_negated
++, op0
= XEXP (op0
, 0);
4965 if (GET_CODE (op1
) == NOT
)
4966 num_negated
++, op1
= XEXP (op1
, 0);
4968 if (num_negated
== 2)
4970 SUBST (XEXP (x
, 0), op0
);
4971 SUBST (XEXP (x
, 1), op1
);
4973 else if (num_negated
== 1)
4974 return gen_unary (NOT
, mode
, mode
, gen_binary (XOR
, mode
, op0
, op1
));
4977 /* Convert (xor (and A B) B) to (and (not A) B). The latter may
4978 correspond to a machine insn or result in further simplifications
4979 if B is a constant. */
4981 if (GET_CODE (op0
) == AND
4982 && rtx_equal_p (XEXP (op0
, 1), op1
)
4983 && ! side_effects_p (op1
))
4984 return gen_binary (AND
, mode
,
4985 gen_unary (NOT
, mode
, mode
, XEXP (op0
, 0)),
4988 else if (GET_CODE (op0
) == AND
4989 && rtx_equal_p (XEXP (op0
, 0), op1
)
4990 && ! side_effects_p (op1
))
4991 return gen_binary (AND
, mode
,
4992 gen_unary (NOT
, mode
, mode
, XEXP (op0
, 1)),
4995 /* (xor (comparison foo bar) (const_int 1)) can become the reversed
4996 comparison if STORE_FLAG_VALUE is 1. */
4997 if (STORE_FLAG_VALUE
== 1
4998 && op1
== const1_rtx
4999 && GET_RTX_CLASS (GET_CODE (op0
)) == '<'
5000 && reversible_comparison_p (op0
))
5001 return gen_rtx_combine (reverse_condition (GET_CODE (op0
)),
5002 mode
, XEXP (op0
, 0), XEXP (op0
, 1));
5004 /* (lshiftrt foo C) where C is the number of bits in FOO minus 1
5005 is (lt foo (const_int 0)), so we can perform the above
5006 simplification if STORE_FLAG_VALUE is 1. */
5008 if (STORE_FLAG_VALUE
== 1
5009 && op1
== const1_rtx
5010 && GET_CODE (op0
) == LSHIFTRT
5011 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
5012 && INTVAL (XEXP (op0
, 1)) == GET_MODE_BITSIZE (mode
) - 1)
5013 return gen_rtx_combine (GE
, mode
, XEXP (op0
, 0), const0_rtx
);
5015 /* (xor (comparison foo bar) (const_int sign-bit))
5016 when STORE_FLAG_VALUE is the sign bit. */
5017 if (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
5018 && ((STORE_FLAG_VALUE
& GET_MODE_MASK (mode
))
5019 == (HOST_WIDE_INT
) 1 << (GET_MODE_BITSIZE (mode
) - 1))
5020 && op1
== const_true_rtx
5021 && GET_RTX_CLASS (GET_CODE (op0
)) == '<'
5022 && reversible_comparison_p (op0
))
5023 return gen_rtx_combine (reverse_condition (GET_CODE (op0
)),
5024 mode
, XEXP (op0
, 0), XEXP (op0
, 1));
5034 /* We consider ZERO_EXTRACT, SIGN_EXTRACT, and SIGN_EXTEND as "compound
5035 operations" because they can be replaced with two more basic operations.
5036 ZERO_EXTEND is also considered "compound" because it can be replaced with
5037 an AND operation, which is simpler, though only one operation.
5039 The function expand_compound_operation is called with an rtx expression
5040 and will convert it to the appropriate shifts and AND operations,
5041 simplifying at each stage.
5043 The function make_compound_operation is called to convert an expression
5044 consisting of shifts and ANDs into the equivalent compound expression.
5045 It is the inverse of this function, loosely speaking. */
5048 expand_compound_operation (x
)
5056 switch (GET_CODE (x
))
5061 /* We can't necessarily use a const_int for a multiword mode;
5062 it depends on implicitly extending the value.
5063 Since we don't know the right way to extend it,
5064 we can't tell whether the implicit way is right.
5066 Even for a mode that is no wider than a const_int,
5067 we can't win, because we need to sign extend one of its bits through
5068 the rest of it, and we don't know which bit. */
5069 if (GET_CODE (XEXP (x
, 0)) == CONST_INT
)
5072 /* Return if (subreg:MODE FROM 0) is not a safe replacement for
5073 (zero_extend:MODE FROM) or (sign_extend:MODE FROM). It is for any MEM
5074 because (SUBREG (MEM...)) is guaranteed to cause the MEM to be
5075 reloaded. If not for that, MEM's would very rarely be safe.
5077 Reject MODEs bigger than a word, because we might not be able
5078 to reference a two-register group starting with an arbitrary register
5079 (and currently gen_lowpart might crash for a SUBREG). */
5081 if (GET_MODE_SIZE (GET_MODE (XEXP (x
, 0))) > UNITS_PER_WORD
)
5084 len
= GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)));
5085 /* If the inner object has VOIDmode (the only way this can happen
5086 is if it is a ASM_OPERANDS), we can't do anything since we don't
5087 know how much masking to do. */
5096 /* If the operand is a CLOBBER, just return it. */
5097 if (GET_CODE (XEXP (x
, 0)) == CLOBBER
)
5100 if (GET_CODE (XEXP (x
, 1)) != CONST_INT
5101 || GET_CODE (XEXP (x
, 2)) != CONST_INT
5102 || GET_MODE (XEXP (x
, 0)) == VOIDmode
)
5105 len
= INTVAL (XEXP (x
, 1));
5106 pos
= INTVAL (XEXP (x
, 2));
5108 /* If this goes outside the object being extracted, replace the object
5109 with a (use (mem ...)) construct that only combine understands
5110 and is used only for this purpose. */
5111 if (len
+ pos
> GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))))
5112 SUBST (XEXP (x
, 0), gen_rtx (USE
, GET_MODE (x
), XEXP (x
, 0)));
5114 if (BITS_BIG_ENDIAN
)
5115 pos
= GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))) - len
- pos
;
5123 /* We can optimize some special cases of ZERO_EXTEND. */
5124 if (GET_CODE (x
) == ZERO_EXTEND
)
5126 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI if we
5127 know that the last value didn't have any inappropriate bits
5129 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
5130 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
5131 && GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
5132 && (nonzero_bits (XEXP (XEXP (x
, 0), 0), GET_MODE (x
))
5133 & ~ GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
5134 return XEXP (XEXP (x
, 0), 0);
5136 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
5137 if (GET_CODE (XEXP (x
, 0)) == SUBREG
5138 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
5139 && subreg_lowpart_p (XEXP (x
, 0))
5140 && GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
5141 && (nonzero_bits (SUBREG_REG (XEXP (x
, 0)), GET_MODE (x
))
5142 & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x
)))) == 0)
5143 return SUBREG_REG (XEXP (x
, 0));
5145 /* (zero_extend:DI (truncate:SI foo:DI)) is just foo:DI when foo
5146 is a comparison and STORE_FLAG_VALUE permits. This is like
5147 the first case, but it works even when GET_MODE (x) is larger
5148 than HOST_WIDE_INT. */
5149 if (GET_CODE (XEXP (x
, 0)) == TRUNCATE
5150 && GET_MODE (XEXP (XEXP (x
, 0), 0)) == GET_MODE (x
)
5151 && GET_RTX_CLASS (GET_CODE (XEXP (XEXP (x
, 0), 0))) == '<'
5152 && (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
5153 <= HOST_BITS_PER_WIDE_INT
)
5154 && ((HOST_WIDE_INT
) STORE_FLAG_VALUE
5155 & ~ GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
5156 return XEXP (XEXP (x
, 0), 0);
5158 /* Likewise for (zero_extend:DI (subreg:SI foo:DI 0)). */
5159 if (GET_CODE (XEXP (x
, 0)) == SUBREG
5160 && GET_MODE (SUBREG_REG (XEXP (x
, 0))) == GET_MODE (x
)
5161 && subreg_lowpart_p (XEXP (x
, 0))
5162 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x
, 0)))) == '<'
5163 && (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
5164 <= HOST_BITS_PER_WIDE_INT
)
5165 && ((HOST_WIDE_INT
) STORE_FLAG_VALUE
5166 & ~ GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
5167 return SUBREG_REG (XEXP (x
, 0));
5169 /* If sign extension is cheaper than zero extension, then use it
5170 if we know that no extraneous bits are set, and that the high
5172 if (flag_expensive_optimizations
5173 && ((GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
5174 && ((nonzero_bits (XEXP (x
, 0), GET_MODE (x
))
5175 & ~ (((unsigned HOST_WIDE_INT
)
5176 GET_MODE_MASK (GET_MODE (XEXP (x
, 0))))
5179 || (GET_RTX_CLASS (GET_CODE (XEXP (x
, 0))) == '<'
5180 && (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
5181 <= HOST_BITS_PER_WIDE_INT
)
5182 && (((HOST_WIDE_INT
) STORE_FLAG_VALUE
5183 & ~ (((unsigned HOST_WIDE_INT
)
5184 GET_MODE_MASK (GET_MODE (XEXP (x
, 0))))
5188 rtx temp
= gen_rtx (SIGN_EXTEND
, GET_MODE (x
), XEXP (x
, 0));
5190 if (rtx_cost (temp
, SET
) < rtx_cost (x
, SET
))
5191 return expand_compound_operation (temp
);
5195 /* If we reach here, we want to return a pair of shifts. The inner
5196 shift is a left shift of BITSIZE - POS - LEN bits. The outer
5197 shift is a right shift of BITSIZE - LEN bits. It is arithmetic or
5198 logical depending on the value of UNSIGNEDP.
5200 If this was a ZERO_EXTEND or ZERO_EXTRACT, this pair of shifts will be
5201 converted into an AND of a shift.
5203 We must check for the case where the left shift would have a negative
5204 count. This can happen in a case like (x >> 31) & 255 on machines
5205 that can't shift by a constant. On those machines, we would first
5206 combine the shift with the AND to produce a variable-position
5207 extraction. Then the constant of 31 would be substituted in to produce
5208 a such a position. */
5210 modewidth
= GET_MODE_BITSIZE (GET_MODE (x
));
5211 if (modewidth
>= pos
- len
)
5212 tem
= simplify_shift_const (NULL_RTX
, unsignedp
? LSHIFTRT
: ASHIFTRT
,
5214 simplify_shift_const (NULL_RTX
, ASHIFT
,
5217 modewidth
- pos
- len
),
5220 else if (unsignedp
&& len
< HOST_BITS_PER_WIDE_INT
)
5221 tem
= simplify_and_const_int (NULL_RTX
, GET_MODE (x
),
5222 simplify_shift_const (NULL_RTX
, LSHIFTRT
,
5225 ((HOST_WIDE_INT
) 1 << len
) - 1);
5227 /* Any other cases we can't handle. */
5231 /* If we couldn't do this for some reason, return the original
5233 if (GET_CODE (tem
) == CLOBBER
)
5239 /* X is a SET which contains an assignment of one object into
5240 a part of another (such as a bit-field assignment, STRICT_LOW_PART,
5241 or certain SUBREGS). If possible, convert it into a series of
5244 We half-heartedly support variable positions, but do not at all
5245 support variable lengths. */
5248 expand_field_assignment (x
)
5252 rtx pos
; /* Always counts from low bit. */
5255 enum machine_mode compute_mode
;
5257 /* Loop until we find something we can't simplify. */
5260 if (GET_CODE (SET_DEST (x
)) == STRICT_LOW_PART
5261 && GET_CODE (XEXP (SET_DEST (x
), 0)) == SUBREG
)
5263 inner
= SUBREG_REG (XEXP (SET_DEST (x
), 0));
5264 len
= GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x
), 0)));
5265 pos
= GEN_INT (BITS_PER_WORD
* SUBREG_WORD (XEXP (SET_DEST (x
), 0)));
5267 else if (GET_CODE (SET_DEST (x
)) == ZERO_EXTRACT
5268 && GET_CODE (XEXP (SET_DEST (x
), 1)) == CONST_INT
)
5270 inner
= XEXP (SET_DEST (x
), 0);
5271 len
= INTVAL (XEXP (SET_DEST (x
), 1));
5272 pos
= XEXP (SET_DEST (x
), 2);
5274 /* If the position is constant and spans the width of INNER,
5275 surround INNER with a USE to indicate this. */
5276 if (GET_CODE (pos
) == CONST_INT
5277 && INTVAL (pos
) + len
> GET_MODE_BITSIZE (GET_MODE (inner
)))
5278 inner
= gen_rtx (USE
, GET_MODE (SET_DEST (x
)), inner
);
5280 if (BITS_BIG_ENDIAN
)
5282 if (GET_CODE (pos
) == CONST_INT
)
5283 pos
= GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner
)) - len
5285 else if (GET_CODE (pos
) == MINUS
5286 && GET_CODE (XEXP (pos
, 1)) == CONST_INT
5287 && (INTVAL (XEXP (pos
, 1))
5288 == GET_MODE_BITSIZE (GET_MODE (inner
)) - len
))
5289 /* If position is ADJUST - X, new position is X. */
5290 pos
= XEXP (pos
, 0);
5292 pos
= gen_binary (MINUS
, GET_MODE (pos
),
5293 GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner
))
5299 /* A SUBREG between two modes that occupy the same numbers of words
5300 can be done by moving the SUBREG to the source. */
5301 else if (GET_CODE (SET_DEST (x
)) == SUBREG
5302 && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x
)))
5303 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
5304 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x
))))
5305 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)))
5307 x
= gen_rtx (SET
, VOIDmode
, SUBREG_REG (SET_DEST (x
)),
5308 gen_lowpart_for_combine (GET_MODE (SUBREG_REG (SET_DEST (x
))),
5315 while (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
5316 inner
= SUBREG_REG (inner
);
5318 compute_mode
= GET_MODE (inner
);
5320 /* Compute a mask of LEN bits, if we can do this on the host machine. */
5321 if (len
< HOST_BITS_PER_WIDE_INT
)
5322 mask
= GEN_INT (((HOST_WIDE_INT
) 1 << len
) - 1);
5326 /* Now compute the equivalent expression. Make a copy of INNER
5327 for the SET_DEST in case it is a MEM into which we will substitute;
5328 we don't want shared RTL in that case. */
5329 x
= gen_rtx (SET
, VOIDmode
, copy_rtx (inner
),
5330 gen_binary (IOR
, compute_mode
,
5331 gen_binary (AND
, compute_mode
,
5332 gen_unary (NOT
, compute_mode
,
5338 gen_binary (ASHIFT
, compute_mode
,
5339 gen_binary (AND
, compute_mode
,
5340 gen_lowpart_for_combine
5350 /* Return an RTX for a reference to LEN bits of INNER. If POS_RTX is nonzero,
5351 it is an RTX that represents a variable starting position; otherwise,
5352 POS is the (constant) starting bit position (counted from the LSB).
5354 INNER may be a USE. This will occur when we started with a bitfield
5355 that went outside the boundary of the object in memory, which is
5356 allowed on most machines. To isolate this case, we produce a USE
5357 whose mode is wide enough and surround the MEM with it. The only
5358 code that understands the USE is this routine. If it is not removed,
5359 it will cause the resulting insn not to match.
5361 UNSIGNEDP is non-zero for an unsigned reference and zero for a
5364 IN_DEST is non-zero if this is a reference in the destination of a
5365 SET. This is used when a ZERO_ or SIGN_EXTRACT isn't needed. If non-zero,
5366 a STRICT_LOW_PART will be used, if zero, ZERO_EXTEND or SIGN_EXTEND will
5369 IN_COMPARE is non-zero if we are in a COMPARE. This means that a
5370 ZERO_EXTRACT should be built even for bits starting at bit 0.
5372 MODE is the desired mode of the result (if IN_DEST == 0).
5374 The result is an RTX for the extraction or NULL_RTX if the target
5378 make_extraction (mode
, inner
, pos
, pos_rtx
, len
,
5379 unsignedp
, in_dest
, in_compare
)
5380 enum machine_mode mode
;
5386 int in_dest
, in_compare
;
5388 /* This mode describes the size of the storage area
5389 to fetch the overall value from. Within that, we
5390 ignore the POS lowest bits, etc. */
5391 enum machine_mode is_mode
= GET_MODE (inner
);
5392 enum machine_mode inner_mode
;
5393 enum machine_mode wanted_inner_mode
= byte_mode
;
5394 enum machine_mode wanted_inner_reg_mode
= word_mode
;
5395 enum machine_mode pos_mode
= word_mode
;
5396 enum machine_mode extraction_mode
= word_mode
;
5397 enum machine_mode tmode
= mode_for_size (len
, MODE_INT
, 1);
5400 rtx orig_pos_rtx
= pos_rtx
;
5403 /* Get some information about INNER and get the innermost object. */
5404 if (GET_CODE (inner
) == USE
)
5405 /* (use:SI (mem:QI foo)) stands for (mem:SI foo). */
5406 /* We don't need to adjust the position because we set up the USE
5407 to pretend that it was a full-word object. */
5408 spans_byte
= 1, inner
= XEXP (inner
, 0);
5409 else if (GET_CODE (inner
) == SUBREG
&& subreg_lowpart_p (inner
))
5411 /* If going from (subreg:SI (mem:QI ...)) to (mem:QI ...),
5412 consider just the QI as the memory to extract from.
5413 The subreg adds or removes high bits; its mode is
5414 irrelevant to the meaning of this extraction,
5415 since POS and LEN count from the lsb. */
5416 if (GET_CODE (SUBREG_REG (inner
)) == MEM
)
5417 is_mode
= GET_MODE (SUBREG_REG (inner
));
5418 inner
= SUBREG_REG (inner
);
5421 inner_mode
= GET_MODE (inner
);
5423 if (pos_rtx
&& GET_CODE (pos_rtx
) == CONST_INT
)
5424 pos
= INTVAL (pos_rtx
), pos_rtx
= 0;
5426 /* See if this can be done without an extraction. We never can if the
5427 width of the field is not the same as that of some integer mode. For
5428 registers, we can only avoid the extraction if the position is at the
5429 low-order bit and this is either not in the destination or we have the
5430 appropriate STRICT_LOW_PART operation available.
5432 For MEM, we can avoid an extract if the field starts on an appropriate
5433 boundary and we can change the mode of the memory reference. However,
5434 we cannot directly access the MEM if we have a USE and the underlying
5435 MEM is not TMODE. This combination means that MEM was being used in a
5436 context where bits outside its mode were being referenced; that is only
5437 valid in bit-field insns. */
5439 if (tmode
!= BLKmode
5440 && ! (spans_byte
&& inner_mode
!= tmode
)
5441 && ((pos_rtx
== 0 && (pos
% BITS_PER_WORD
) == 0
5442 && GET_CODE (inner
) != MEM
5444 || (GET_CODE (inner
) == REG
5445 && (movstrict_optab
->handlers
[(int) tmode
].insn_code
5446 != CODE_FOR_nothing
))))
5447 || (GET_CODE (inner
) == MEM
&& pos_rtx
== 0
5449 % (STRICT_ALIGNMENT
? GET_MODE_ALIGNMENT (tmode
)
5450 : BITS_PER_UNIT
)) == 0
5451 /* We can't do this if we are widening INNER_MODE (it
5452 may not be aligned, for one thing). */
5453 && GET_MODE_BITSIZE (inner_mode
) >= GET_MODE_BITSIZE (tmode
)
5454 && (inner_mode
== tmode
5455 || (! mode_dependent_address_p (XEXP (inner
, 0))
5456 && ! MEM_VOLATILE_P (inner
))))))
5458 /* If INNER is a MEM, make a new MEM that encompasses just the desired
5459 field. If the original and current mode are the same, we need not
5460 adjust the offset. Otherwise, we do if bytes big endian.
5462 If INNER is not a MEM, get a piece consisting of just the field
5463 of interest (in this case POS % BITS_PER_WORD must be 0). */
5465 if (GET_CODE (inner
) == MEM
)
5468 /* POS counts from lsb, but make OFFSET count in memory order. */
5469 if (BYTES_BIG_ENDIAN
)
5470 offset
= (GET_MODE_BITSIZE (is_mode
) - len
- pos
) / BITS_PER_UNIT
;
5472 offset
= pos
/ BITS_PER_UNIT
;
5474 new = gen_rtx (MEM
, tmode
, plus_constant (XEXP (inner
, 0), offset
));
5475 RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (inner
);
5476 MEM_VOLATILE_P (new) = MEM_VOLATILE_P (inner
);
5477 MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (inner
);
5479 else if (GET_CODE (inner
) == REG
)
5481 /* We can't call gen_lowpart_for_combine here since we always want
5482 a SUBREG and it would sometimes return a new hard register. */
5483 if (tmode
!= inner_mode
)
5484 new = gen_rtx (SUBREG
, tmode
, inner
,
5486 && GET_MODE_SIZE (inner_mode
) > UNITS_PER_WORD
5487 ? (((GET_MODE_SIZE (inner_mode
)
5488 - GET_MODE_SIZE (tmode
))
5490 - pos
/ BITS_PER_WORD
)
5491 : pos
/ BITS_PER_WORD
));
5496 new = force_to_mode (inner
, tmode
,
5497 len
>= HOST_BITS_PER_WIDE_INT
5498 ? GET_MODE_MASK (tmode
)
5499 : ((HOST_WIDE_INT
) 1 << len
) - 1,
5502 /* If this extraction is going into the destination of a SET,
5503 make a STRICT_LOW_PART unless we made a MEM. */
5506 return (GET_CODE (new) == MEM
? new
5507 : (GET_CODE (new) != SUBREG
5508 ? gen_rtx (CLOBBER
, tmode
, const0_rtx
)
5509 : gen_rtx_combine (STRICT_LOW_PART
, VOIDmode
, new)));
5511 /* Otherwise, sign- or zero-extend unless we already are in the
5514 return (mode
== tmode
? new
5515 : gen_rtx_combine (unsignedp
? ZERO_EXTEND
: SIGN_EXTEND
,
5519 /* Unless this is a COMPARE or we have a funny memory reference,
5520 don't do anything with zero-extending field extracts starting at
5521 the low-order bit since they are simple AND operations. */
5522 if (pos_rtx
== 0 && pos
== 0 && ! in_dest
5523 && ! in_compare
&& ! spans_byte
&& unsignedp
)
5526 /* Unless we are allowed to span bytes, reject this if we would be
5527 spanning bytes or if the position is not a constant and the length
5528 is not 1. In all other cases, we would only be going outside
5529 out object in cases when an original shift would have been
5532 && ((pos_rtx
== 0 && pos
+ len
> GET_MODE_BITSIZE (is_mode
))
5533 || (pos_rtx
!= 0 && len
!= 1)))
5536 /* Get the mode to use should INNER not be a MEM, the mode for the position,
5537 and the mode for the result. */
5541 wanted_inner_reg_mode
= insn_operand_mode
[(int) CODE_FOR_insv
][0];
5542 pos_mode
= insn_operand_mode
[(int) CODE_FOR_insv
][2];
5543 extraction_mode
= insn_operand_mode
[(int) CODE_FOR_insv
][3];
5548 if (! in_dest
&& unsignedp
)
5550 wanted_inner_reg_mode
= insn_operand_mode
[(int) CODE_FOR_extzv
][1];
5551 pos_mode
= insn_operand_mode
[(int) CODE_FOR_extzv
][3];
5552 extraction_mode
= insn_operand_mode
[(int) CODE_FOR_extzv
][0];
5557 if (! in_dest
&& ! unsignedp
)
5559 wanted_inner_reg_mode
= insn_operand_mode
[(int) CODE_FOR_extv
][1];
5560 pos_mode
= insn_operand_mode
[(int) CODE_FOR_extv
][3];
5561 extraction_mode
= insn_operand_mode
[(int) CODE_FOR_extv
][0];
5565 /* Never narrow an object, since that might not be safe. */
5567 if (mode
!= VOIDmode
5568 && GET_MODE_SIZE (extraction_mode
) < GET_MODE_SIZE (mode
))
5569 extraction_mode
= mode
;
5571 if (pos_rtx
&& GET_MODE (pos_rtx
) != VOIDmode
5572 && GET_MODE_SIZE (pos_mode
) < GET_MODE_SIZE (GET_MODE (pos_rtx
)))
5573 pos_mode
= GET_MODE (pos_rtx
);
5575 /* If this is not from memory, the desired mode is wanted_inner_reg_mode;
5576 if we have to change the mode of memory and cannot, the desired mode is
5578 if (GET_CODE (inner
) != MEM
)
5579 wanted_inner_mode
= wanted_inner_reg_mode
;
5580 else if (inner_mode
!= wanted_inner_mode
5581 && (mode_dependent_address_p (XEXP (inner
, 0))
5582 || MEM_VOLATILE_P (inner
)))
5583 wanted_inner_mode
= extraction_mode
;
5587 if (BITS_BIG_ENDIAN
)
5589 /* POS is passed as if BITS_BIG_ENDIAN == 0, so we need to convert it to
5590 BITS_BIG_ENDIAN style. If position is constant, compute new
5591 position. Otherwise, build subtraction.
5592 Note that POS is relative to the mode of the original argument.
5593 If it's a MEM we need to recompute POS relative to that.
5594 However, if we're extracting from (or inserting into) a register,
5595 we want to recompute POS relative to wanted_inner_mode. */
5596 int width
= (GET_CODE (inner
) == MEM
5597 ? GET_MODE_BITSIZE (is_mode
)
5598 : GET_MODE_BITSIZE (wanted_inner_mode
));
5601 pos
= width
- len
- pos
;
5604 = gen_rtx_combine (MINUS
, GET_MODE (pos_rtx
),
5605 GEN_INT (width
- len
), pos_rtx
);
5606 /* POS may be less than 0 now, but we check for that below.
5607 Note that it can only be less than 0 if GET_CODE (inner) != MEM. */
5610 /* If INNER has a wider mode, make it smaller. If this is a constant
5611 extract, try to adjust the byte to point to the byte containing
5613 if (wanted_inner_mode
!= VOIDmode
5614 && GET_MODE_SIZE (wanted_inner_mode
) < GET_MODE_SIZE (is_mode
)
5615 && ((GET_CODE (inner
) == MEM
5616 && (inner_mode
== wanted_inner_mode
5617 || (! mode_dependent_address_p (XEXP (inner
, 0))
5618 && ! MEM_VOLATILE_P (inner
))))))
5622 /* The computations below will be correct if the machine is big
5623 endian in both bits and bytes or little endian in bits and bytes.
5624 If it is mixed, we must adjust. */
5626 /* If bytes are big endian and we had a paradoxical SUBREG, we must
5627 adjust OFFSET to compensate. */
5628 if (BYTES_BIG_ENDIAN
5630 && GET_MODE_SIZE (inner_mode
) < GET_MODE_SIZE (is_mode
))
5631 offset
-= GET_MODE_SIZE (is_mode
) - GET_MODE_SIZE (inner_mode
);
5633 /* If this is a constant position, we can move to the desired byte. */
5636 offset
+= pos
/ BITS_PER_UNIT
;
5637 pos
%= GET_MODE_BITSIZE (wanted_inner_mode
);
5640 if (BYTES_BIG_ENDIAN
!= BITS_BIG_ENDIAN
5642 && is_mode
!= wanted_inner_mode
)
5643 offset
= (GET_MODE_SIZE (is_mode
)
5644 - GET_MODE_SIZE (wanted_inner_mode
) - offset
);
5646 if (offset
!= 0 || inner_mode
!= wanted_inner_mode
)
5648 rtx newmem
= gen_rtx (MEM
, wanted_inner_mode
,
5649 plus_constant (XEXP (inner
, 0), offset
));
5650 RTX_UNCHANGING_P (newmem
) = RTX_UNCHANGING_P (inner
);
5651 MEM_VOLATILE_P (newmem
) = MEM_VOLATILE_P (inner
);
5652 MEM_IN_STRUCT_P (newmem
) = MEM_IN_STRUCT_P (inner
);
5657 /* If INNER is not memory, we can always get it into the proper mode. If we
5658 are changing its mode, POS must be a constant and smaller than the size
5660 else if (GET_CODE (inner
) != MEM
)
5662 if (GET_MODE (inner
) != wanted_inner_mode
5664 || orig_pos
+ len
> GET_MODE_BITSIZE (wanted_inner_mode
)))
5667 inner
= force_to_mode (inner
, wanted_inner_mode
,
5669 || len
+ orig_pos
>= HOST_BITS_PER_WIDE_INT
5670 ? GET_MODE_MASK (wanted_inner_mode
)
5671 : (((HOST_WIDE_INT
) 1 << len
) - 1) << orig_pos
,
5675 /* Adjust mode of POS_RTX, if needed. If we want a wider mode, we
5676 have to zero extend. Otherwise, we can just use a SUBREG. */
5678 && GET_MODE_SIZE (pos_mode
) > GET_MODE_SIZE (GET_MODE (pos_rtx
)))
5679 pos_rtx
= gen_rtx_combine (ZERO_EXTEND
, pos_mode
, pos_rtx
);
5680 else if (pos_rtx
!= 0
5681 && GET_MODE_SIZE (pos_mode
) < GET_MODE_SIZE (GET_MODE (pos_rtx
)))
5682 pos_rtx
= gen_lowpart_for_combine (pos_mode
, pos_rtx
);
5684 /* Make POS_RTX unless we already have it and it is correct. If we don't
5685 have a POS_RTX but we do have an ORIG_POS_RTX, the latter must
5687 if (pos_rtx
== 0 && orig_pos_rtx
!= 0 && INTVAL (orig_pos_rtx
) == pos
)
5688 pos_rtx
= orig_pos_rtx
;
5690 else if (pos_rtx
== 0)
5691 pos_rtx
= GEN_INT (pos
);
5693 /* Make the required operation. See if we can use existing rtx. */
5694 new = gen_rtx_combine (unsignedp
? ZERO_EXTRACT
: SIGN_EXTRACT
,
5695 extraction_mode
, inner
, GEN_INT (len
), pos_rtx
);
5697 new = gen_lowpart_for_combine (mode
, new);
5702 /* See if X contains an ASHIFT of COUNT or more bits that can be commuted
5703 with any other operations in X. Return X without that shift if so. */
5706 extract_left_shift (x
, count
)
5710 enum rtx_code code
= GET_CODE (x
);
5711 enum machine_mode mode
= GET_MODE (x
);
5717 /* This is the shift itself. If it is wide enough, we will return
5718 either the value being shifted if the shift count is equal to
5719 COUNT or a shift for the difference. */
5720 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
5721 && INTVAL (XEXP (x
, 1)) >= count
)
5722 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (x
, 0),
5723 INTVAL (XEXP (x
, 1)) - count
);
5727 if ((tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
5728 return gen_unary (code
, mode
, mode
, tem
);
5732 case PLUS
: case IOR
: case XOR
: case AND
:
5733 /* If we can safely shift this constant and we find the inner shift,
5734 make a new operation. */
5735 if (GET_CODE (XEXP (x
,1)) == CONST_INT
5736 && (INTVAL (XEXP (x
, 1)) & (((HOST_WIDE_INT
) 1 << count
)) - 1) == 0
5737 && (tem
= extract_left_shift (XEXP (x
, 0), count
)) != 0)
5738 return gen_binary (code
, mode
, tem
,
5739 GEN_INT (INTVAL (XEXP (x
, 1)) >> count
));
5750 /* Look at the expression rooted at X. Look for expressions
5751 equivalent to ZERO_EXTRACT, SIGN_EXTRACT, ZERO_EXTEND, SIGN_EXTEND.
5752 Form these expressions.
5754 Return the new rtx, usually just X.
5756 Also, for machines like the Vax that don't have logical shift insns,
5757 try to convert logical to arithmetic shift operations in cases where
5758 they are equivalent. This undoes the canonicalizations to logical
5759 shifts done elsewhere.
5761 We try, as much as possible, to re-use rtl expressions to save memory.
5763 IN_CODE says what kind of expression we are processing. Normally, it is
5764 SET. In a memory address (inside a MEM, PLUS or minus, the latter two
5765 being kludges), it is MEM. When processing the arguments of a comparison
5766 or a COMPARE against zero, it is COMPARE. */
5769 make_compound_operation (x
, in_code
)
5771 enum rtx_code in_code
;
5773 enum rtx_code code
= GET_CODE (x
);
5774 enum machine_mode mode
= GET_MODE (x
);
5775 int mode_width
= GET_MODE_BITSIZE (mode
);
5777 enum rtx_code next_code
;
5783 /* Select the code to be used in recursive calls. Once we are inside an
5784 address, we stay there. If we have a comparison, set to COMPARE,
5785 but once inside, go back to our default of SET. */
5787 next_code
= (code
== MEM
|| code
== PLUS
|| code
== MINUS
? MEM
5788 : ((code
== COMPARE
|| GET_RTX_CLASS (code
) == '<')
5789 && XEXP (x
, 1) == const0_rtx
) ? COMPARE
5790 : in_code
== COMPARE
? SET
: in_code
);
5792 /* Process depending on the code of this operation. If NEW is set
5793 non-zero, it will be returned. */
5798 /* Convert shifts by constants into multiplications if inside
5800 if (in_code
== MEM
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
5801 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
5802 && INTVAL (XEXP (x
, 1)) >= 0)
5804 new = make_compound_operation (XEXP (x
, 0), next_code
);
5805 new = gen_rtx_combine (MULT
, mode
, new,
5806 GEN_INT ((HOST_WIDE_INT
) 1
5807 << INTVAL (XEXP (x
, 1))));
5812 /* If the second operand is not a constant, we can't do anything
5814 if (GET_CODE (XEXP (x
, 1)) != CONST_INT
)
5817 /* If the constant is a power of two minus one and the first operand
5818 is a logical right shift, make an extraction. */
5819 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
5820 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)) + 1)) >= 0)
5822 new = make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
5823 new = make_extraction (mode
, new, 0, XEXP (XEXP (x
, 0), 1), i
, 1,
5824 0, in_code
== COMPARE
);
5827 /* Same as previous, but for (subreg (lshiftrt ...)) in first op. */
5828 else if (GET_CODE (XEXP (x
, 0)) == SUBREG
5829 && subreg_lowpart_p (XEXP (x
, 0))
5830 && GET_CODE (SUBREG_REG (XEXP (x
, 0))) == LSHIFTRT
5831 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)) + 1)) >= 0)
5833 new = make_compound_operation (XEXP (SUBREG_REG (XEXP (x
, 0)), 0),
5835 new = make_extraction (GET_MODE (SUBREG_REG (XEXP (x
, 0))), new, 0,
5836 XEXP (SUBREG_REG (XEXP (x
, 0)), 1), i
, 1,
5837 0, in_code
== COMPARE
);
5839 /* Same as previous, but for (xor/ior (lshiftrt...) (lshiftrt...)). */
5840 else if ((GET_CODE (XEXP (x
, 0)) == XOR
5841 || GET_CODE (XEXP (x
, 0)) == IOR
)
5842 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == LSHIFTRT
5843 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == LSHIFTRT
5844 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)) + 1)) >= 0)
5846 /* Apply the distributive law, and then try to make extractions. */
5847 new = gen_rtx_combine (GET_CODE (XEXP (x
, 0)), mode
,
5848 gen_rtx (AND
, mode
, XEXP (XEXP (x
, 0), 0),
5850 gen_rtx (AND
, mode
, XEXP (XEXP (x
, 0), 1),
5852 new = make_compound_operation (new, in_code
);
5855 /* If we are have (and (rotate X C) M) and C is larger than the number
5856 of bits in M, this is an extraction. */
5858 else if (GET_CODE (XEXP (x
, 0)) == ROTATE
5859 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
5860 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)) + 1)) >= 0
5861 && i
<= INTVAL (XEXP (XEXP (x
, 0), 1)))
5863 new = make_compound_operation (XEXP (XEXP (x
, 0), 0), next_code
);
5864 new = make_extraction (mode
, new,
5865 (GET_MODE_BITSIZE (mode
)
5866 - INTVAL (XEXP (XEXP (x
, 0), 1))),
5867 NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
5870 /* On machines without logical shifts, if the operand of the AND is
5871 a logical shift and our mask turns off all the propagated sign
5872 bits, we can replace the logical shift with an arithmetic shift. */
5873 else if (ashr_optab
->handlers
[(int) mode
].insn_code
!= CODE_FOR_nothing
5874 && (lshr_optab
->handlers
[(int) mode
].insn_code
5875 == CODE_FOR_nothing
)
5876 && GET_CODE (XEXP (x
, 0)) == LSHIFTRT
5877 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
5878 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
5879 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
5880 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
5882 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
5884 mask
>>= INTVAL (XEXP (XEXP (x
, 0), 1));
5885 if ((INTVAL (XEXP (x
, 1)) & ~mask
) == 0)
5887 gen_rtx_combine (ASHIFTRT
, mode
,
5888 make_compound_operation (XEXP (XEXP (x
, 0), 0),
5890 XEXP (XEXP (x
, 0), 1)));
5893 /* If the constant is one less than a power of two, this might be
5894 representable by an extraction even if no shift is present.
5895 If it doesn't end up being a ZERO_EXTEND, we will ignore it unless
5896 we are in a COMPARE. */
5897 else if ((i
= exact_log2 (INTVAL (XEXP (x
, 1)) + 1)) >= 0)
5898 new = make_extraction (mode
,
5899 make_compound_operation (XEXP (x
, 0),
5901 0, NULL_RTX
, i
, 1, 0, in_code
== COMPARE
);
5903 /* If we are in a comparison and this is an AND with a power of two,
5904 convert this into the appropriate bit extract. */
5905 else if (in_code
== COMPARE
5906 && (i
= exact_log2 (INTVAL (XEXP (x
, 1)))) >= 0)
5907 new = make_extraction (mode
,
5908 make_compound_operation (XEXP (x
, 0),
5910 i
, NULL_RTX
, 1, 1, 0, 1);
5915 /* If the sign bit is known to be zero, replace this with an
5916 arithmetic shift. */
5917 if (ashr_optab
->handlers
[(int) mode
].insn_code
== CODE_FOR_nothing
5918 && lshr_optab
->handlers
[(int) mode
].insn_code
!= CODE_FOR_nothing
5919 && mode_width
<= HOST_BITS_PER_WIDE_INT
5920 && (nonzero_bits (XEXP (x
, 0), mode
) & (1 << (mode_width
- 1))) == 0)
5922 new = gen_rtx_combine (ASHIFTRT
, mode
,
5923 make_compound_operation (XEXP (x
, 0),
5929 /* ... fall through ... */
5935 /* If we have (ashiftrt (ashift foo C1) C2) with C2 >= C1,
5936 this is a SIGN_EXTRACT. */
5937 if (GET_CODE (rhs
) == CONST_INT
5938 && GET_CODE (lhs
) == ASHIFT
5939 && GET_CODE (XEXP (lhs
, 1)) == CONST_INT
5940 && INTVAL (rhs
) >= INTVAL (XEXP (lhs
, 1)))
5942 new = make_compound_operation (XEXP (lhs
, 0), next_code
);
5943 new = make_extraction (mode
, new,
5944 INTVAL (rhs
) - INTVAL (XEXP (lhs
, 1)),
5945 NULL_RTX
, mode_width
- INTVAL (rhs
),
5946 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
5949 /* See if we have operations between an ASHIFTRT and an ASHIFT.
5950 If so, try to merge the shifts into a SIGN_EXTEND. We could
5951 also do this for some cases of SIGN_EXTRACT, but it doesn't
5952 seem worth the effort; the case checked for occurs on Alpha. */
5954 if (GET_RTX_CLASS (GET_CODE (lhs
)) != 'o'
5955 && ! (GET_CODE (lhs
) == SUBREG
5956 && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (lhs
))) == 'o'))
5957 && GET_CODE (rhs
) == CONST_INT
5958 && INTVAL (rhs
) < HOST_BITS_PER_WIDE_INT
5959 && (new = extract_left_shift (lhs
, INTVAL (rhs
))) != 0)
5960 new = make_extraction (mode
, make_compound_operation (new, next_code
),
5961 0, NULL_RTX
, mode_width
- INTVAL (rhs
),
5962 code
== LSHIFTRT
, 0, in_code
== COMPARE
);
5967 /* Call ourselves recursively on the inner expression. If we are
5968 narrowing the object and it has a different RTL code from
5969 what it originally did, do this SUBREG as a force_to_mode. */
5971 tem
= make_compound_operation (SUBREG_REG (x
), in_code
);
5972 if (GET_CODE (tem
) != GET_CODE (SUBREG_REG (x
))
5973 && GET_MODE_SIZE (mode
) < GET_MODE_SIZE (GET_MODE (tem
))
5974 && subreg_lowpart_p (x
))
5976 rtx newer
= force_to_mode (tem
, mode
,
5977 GET_MODE_MASK (mode
), NULL_RTX
, 0);
5979 /* If we have something other than a SUBREG, we might have
5980 done an expansion, so rerun outselves. */
5981 if (GET_CODE (newer
) != SUBREG
)
5982 newer
= make_compound_operation (newer
, in_code
);
5994 x
= gen_lowpart_for_combine (mode
, new);
5995 code
= GET_CODE (x
);
5998 /* Now recursively process each operand of this operation. */
5999 fmt
= GET_RTX_FORMAT (code
);
6000 for (i
= 0; i
< GET_RTX_LENGTH (code
); i
++)
6003 new = make_compound_operation (XEXP (x
, i
), next_code
);
6004 SUBST (XEXP (x
, i
), new);
6010 /* Given M see if it is a value that would select a field of bits
6011 within an item, but not the entire word. Return -1 if not.
6012 Otherwise, return the starting position of the field, where 0 is the
6015 *PLEN is set to the length of the field. */
6018 get_pos_from_mask (m
, plen
)
6019 unsigned HOST_WIDE_INT m
;
6022 /* Get the bit number of the first 1 bit from the right, -1 if none. */
6023 int pos
= exact_log2 (m
& - m
);
6028 /* Now shift off the low-order zero bits and see if we have a power of
6030 *plen
= exact_log2 ((m
>> pos
) + 1);
6038 /* See if X can be simplified knowing that we will only refer to it in
6039 MODE and will only refer to those bits that are nonzero in MASK.
6040 If other bits are being computed or if masking operations are done
6041 that select a superset of the bits in MASK, they can sometimes be
6044 Return a possibly simplified expression, but always convert X to
6045 MODE. If X is a CONST_INT, AND the CONST_INT with MASK.
6047 Also, if REG is non-zero and X is a register equal in value to REG,
6050 If JUST_SELECT is nonzero, don't optimize by noticing that bits in MASK
6051 are all off in X. This is used when X will be complemented, by either
6052 NOT, NEG, or XOR. */
6055 force_to_mode (x
, mode
, mask
, reg
, just_select
)
6057 enum machine_mode mode
;
6058 unsigned HOST_WIDE_INT mask
;
6062 enum rtx_code code
= GET_CODE (x
);
6063 int next_select
= just_select
|| code
== XOR
|| code
== NOT
|| code
== NEG
;
6064 enum machine_mode op_mode
;
6065 unsigned HOST_WIDE_INT fuller_mask
, nonzero
;
6068 /* If this is a CALL or ASM_OPERANDS, don't do anything. Some of the
6069 code below will do the wrong thing since the mode of such an
6070 expression is VOIDmode.
6072 Also do nothing if X is a CLOBBER; this can happen if X was
6073 the return value from a call to gen_lowpart_for_combine. */
6074 if (code
== CALL
|| code
== ASM_OPERANDS
|| code
== CLOBBER
)
6077 /* We want to perform the operation is its present mode unless we know
6078 that the operation is valid in MODE, in which case we do the operation
6080 op_mode
= ((GET_MODE_CLASS (mode
) == GET_MODE_CLASS (GET_MODE (x
))
6081 && code_to_optab
[(int) code
] != 0
6082 && (code_to_optab
[(int) code
]->handlers
[(int) mode
].insn_code
6083 != CODE_FOR_nothing
))
6084 ? mode
: GET_MODE (x
));
6086 /* It is not valid to do a right-shift in a narrower mode
6087 than the one it came in with. */
6088 if ((code
== LSHIFTRT
|| code
== ASHIFTRT
)
6089 && GET_MODE_BITSIZE (mode
) < GET_MODE_BITSIZE (GET_MODE (x
)))
6090 op_mode
= GET_MODE (x
);
6092 /* Truncate MASK to fit OP_MODE. */
6094 mask
&= GET_MODE_MASK (op_mode
);
6096 /* When we have an arithmetic operation, or a shift whose count we
6097 do not know, we need to assume that all bit the up to the highest-order
6098 bit in MASK will be needed. This is how we form such a mask. */
6100 fuller_mask
= (GET_MODE_BITSIZE (op_mode
) >= HOST_BITS_PER_WIDE_INT
6101 ? GET_MODE_MASK (op_mode
)
6102 : ((HOST_WIDE_INT
) 1 << (floor_log2 (mask
) + 1)) - 1);
6104 fuller_mask
= ~ (HOST_WIDE_INT
) 0;
6106 /* Determine what bits of X are guaranteed to be (non)zero. */
6107 nonzero
= nonzero_bits (x
, mode
);
6109 /* If none of the bits in X are needed, return a zero. */
6110 if (! just_select
&& (nonzero
& mask
) == 0)
6113 /* If X is a CONST_INT, return a new one. Do this here since the
6114 test below will fail. */
6115 if (GET_CODE (x
) == CONST_INT
)
6117 HOST_WIDE_INT cval
= INTVAL (x
) & mask
;
6118 int width
= GET_MODE_BITSIZE (mode
);
6120 /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative
6121 number, sign extend it. */
6122 if (width
> 0 && width
< HOST_BITS_PER_WIDE_INT
6123 && (cval
& ((HOST_WIDE_INT
) 1 << (width
- 1))) != 0)
6124 cval
|= (HOST_WIDE_INT
) -1 << width
;
6126 return GEN_INT (cval
);
6129 /* If X is narrower than MODE and we want all the bits in X's mode, just
6130 get X in the proper mode. */
6131 if (GET_MODE_SIZE (GET_MODE (x
)) < GET_MODE_SIZE (mode
)
6132 && (GET_MODE_MASK (GET_MODE (x
)) & ~ mask
) == 0)
6133 return gen_lowpart_for_combine (mode
, x
);
6135 /* If we aren't changing the mode, X is not a SUBREG, and all zero bits in
6136 MASK are already known to be zero in X, we need not do anything. */
6137 if (GET_MODE (x
) == mode
&& code
!= SUBREG
&& (~ mask
& nonzero
) == 0)
6143 /* If X is a (clobber (const_int)), return it since we know we are
6144 generating something that won't match. */
6148 /* X is a (use (mem ..)) that was made from a bit-field extraction that
6149 spanned the boundary of the MEM. If we are now masking so it is
6150 within that boundary, we don't need the USE any more. */
6151 if (! BITS_BIG_ENDIAN
6152 && (mask
& ~ GET_MODE_MASK (GET_MODE (XEXP (x
, 0)))) == 0)
6153 return force_to_mode (XEXP (x
, 0), mode
, mask
, reg
, next_select
);
6160 x
= expand_compound_operation (x
);
6161 if (GET_CODE (x
) != code
)
6162 return force_to_mode (x
, mode
, mask
, reg
, next_select
);
6166 if (reg
!= 0 && (rtx_equal_p (get_last_value (reg
), x
)
6167 || rtx_equal_p (reg
, get_last_value (x
))))
6172 if (subreg_lowpart_p (x
)
6173 /* We can ignore the effect of this SUBREG if it narrows the mode or
6174 if the constant masks to zero all the bits the mode doesn't
6176 && ((GET_MODE_SIZE (GET_MODE (x
))
6177 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
6179 & GET_MODE_MASK (GET_MODE (x
))
6180 & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x
)))))))
6181 return force_to_mode (SUBREG_REG (x
), mode
, mask
, reg
, next_select
);
6185 /* If this is an AND with a constant, convert it into an AND
6186 whose constant is the AND of that constant with MASK. If it
6187 remains an AND of MASK, delete it since it is redundant. */
6189 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
6191 x
= simplify_and_const_int (x
, op_mode
, XEXP (x
, 0),
6192 mask
& INTVAL (XEXP (x
, 1)));
6194 /* If X is still an AND, see if it is an AND with a mask that
6195 is just some low-order bits. If so, and it is MASK, we don't
6198 if (GET_CODE (x
) == AND
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
6199 && INTVAL (XEXP (x
, 1)) == mask
)
6202 /* If it remains an AND, try making another AND with the bits
6203 in the mode mask that aren't in MASK turned on. If the
6204 constant in the AND is wide enough, this might make a
6205 cheaper constant. */
6207 if (GET_CODE (x
) == AND
&& GET_CODE (XEXP (x
, 1)) == CONST_INT
6208 && GET_MODE_MASK (GET_MODE (x
)) != mask
6209 && GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
)
6211 HOST_WIDE_INT cval
= (INTVAL (XEXP (x
, 1))
6212 | (GET_MODE_MASK (GET_MODE (x
)) & ~ mask
));
6213 int width
= GET_MODE_BITSIZE (GET_MODE (x
));
6216 /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative
6217 number, sign extend it. */
6218 if (width
> 0 && width
< HOST_BITS_PER_WIDE_INT
6219 && (cval
& ((HOST_WIDE_INT
) 1 << (width
- 1))) != 0)
6220 cval
|= (HOST_WIDE_INT
) -1 << width
;
6222 y
= gen_binary (AND
, GET_MODE (x
), XEXP (x
, 0), GEN_INT (cval
));
6223 if (rtx_cost (y
, SET
) < rtx_cost (x
, SET
))
6233 /* In (and (plus FOO C1) M), if M is a mask that just turns off
6234 low-order bits (as in an alignment operation) and FOO is already
6235 aligned to that boundary, mask C1 to that boundary as well.
6236 This may eliminate that PLUS and, later, the AND. */
6239 int width
= GET_MODE_BITSIZE (mode
);
6240 unsigned HOST_WIDE_INT smask
= mask
;
6242 /* If MODE is narrower than HOST_WIDE_INT and mask is a negative
6243 number, sign extend it. */
6245 if (width
< HOST_BITS_PER_WIDE_INT
6246 && (smask
& ((HOST_WIDE_INT
) 1 << (width
- 1))) != 0)
6247 smask
|= (HOST_WIDE_INT
) -1 << width
;
6249 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
6250 && exact_log2 (- smask
) >= 0
6251 && (nonzero_bits (XEXP (x
, 0), mode
) & ~ mask
) == 0
6252 && (INTVAL (XEXP (x
, 1)) & ~ mask
) != 0)
6253 return force_to_mode (plus_constant (XEXP (x
, 0),
6254 INTVAL (XEXP (x
, 1)) & mask
),
6255 mode
, mask
, reg
, next_select
);
6258 /* ... fall through ... */
6262 /* For PLUS, MINUS and MULT, we need any bits less significant than the
6263 most significant bit in MASK since carries from those bits will
6264 affect the bits we are interested in. */
6270 /* If X is (ior (lshiftrt FOO C1) C2), try to commute the IOR and
6271 LSHIFTRT so we end up with an (and (lshiftrt (ior ...) ...) ...)
6272 operation which may be a bitfield extraction. Ensure that the
6273 constant we form is not wider than the mode of X. */
6275 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
6276 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
6277 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
6278 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
6279 && GET_CODE (XEXP (x
, 1)) == CONST_INT
6280 && ((INTVAL (XEXP (XEXP (x
, 0), 1))
6281 + floor_log2 (INTVAL (XEXP (x
, 1))))
6282 < GET_MODE_BITSIZE (GET_MODE (x
)))
6283 && (INTVAL (XEXP (x
, 1))
6284 & ~ nonzero_bits (XEXP (x
, 0), GET_MODE (x
))) == 0)
6286 temp
= GEN_INT ((INTVAL (XEXP (x
, 1)) & mask
)
6287 << INTVAL (XEXP (XEXP (x
, 0), 1)));
6288 temp
= gen_binary (GET_CODE (x
), GET_MODE (x
),
6289 XEXP (XEXP (x
, 0), 0), temp
);
6290 x
= gen_binary (LSHIFTRT
, GET_MODE (x
), temp
,
6291 XEXP (XEXP (x
, 0), 1));
6292 return force_to_mode (x
, mode
, mask
, reg
, next_select
);
6296 /* For most binary operations, just propagate into the operation and
6297 change the mode if we have an operation of that mode. */
6299 op0
= gen_lowpart_for_combine (op_mode
,
6300 force_to_mode (XEXP (x
, 0), mode
, mask
,
6302 op1
= gen_lowpart_for_combine (op_mode
,
6303 force_to_mode (XEXP (x
, 1), mode
, mask
,
6306 /* If OP1 is a CONST_INT and X is an IOR or XOR, clear bits outside
6307 MASK since OP1 might have been sign-extended but we never want
6308 to turn on extra bits, since combine might have previously relied
6309 on them being off. */
6310 if (GET_CODE (op1
) == CONST_INT
&& (code
== IOR
|| code
== XOR
)
6311 && (INTVAL (op1
) & mask
) != 0)
6312 op1
= GEN_INT (INTVAL (op1
) & mask
);
6314 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
6315 x
= gen_binary (code
, op_mode
, op0
, op1
);
6319 /* For left shifts, do the same, but just for the first operand.
6320 However, we cannot do anything with shifts where we cannot
6321 guarantee that the counts are smaller than the size of the mode
6322 because such a count will have a different meaning in a
6325 if (! (GET_CODE (XEXP (x
, 1)) == CONST_INT
6326 && INTVAL (XEXP (x
, 1)) >= 0
6327 && INTVAL (XEXP (x
, 1)) < GET_MODE_BITSIZE (mode
))
6328 && ! (GET_MODE (XEXP (x
, 1)) != VOIDmode
6329 && (nonzero_bits (XEXP (x
, 1), GET_MODE (XEXP (x
, 1)))
6330 < (unsigned HOST_WIDE_INT
) GET_MODE_BITSIZE (mode
))))
6333 /* If the shift count is a constant and we can do arithmetic in
6334 the mode of the shift, refine which bits we need. Otherwise, use the
6335 conservative form of the mask. */
6336 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
6337 && INTVAL (XEXP (x
, 1)) >= 0
6338 && INTVAL (XEXP (x
, 1)) < GET_MODE_BITSIZE (op_mode
)
6339 && GET_MODE_BITSIZE (op_mode
) <= HOST_BITS_PER_WIDE_INT
)
6340 mask
>>= INTVAL (XEXP (x
, 1));
6344 op0
= gen_lowpart_for_combine (op_mode
,
6345 force_to_mode (XEXP (x
, 0), op_mode
,
6346 mask
, reg
, next_select
));
6348 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
6349 x
= gen_binary (code
, op_mode
, op0
, XEXP (x
, 1));
6353 /* Here we can only do something if the shift count is a constant,
6354 this shift constant is valid for the host, and we can do arithmetic
6357 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
6358 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
6359 && GET_MODE_BITSIZE (op_mode
) <= HOST_BITS_PER_WIDE_INT
)
6361 rtx inner
= XEXP (x
, 0);
6363 /* Select the mask of the bits we need for the shift operand. */
6364 mask
<<= INTVAL (XEXP (x
, 1));
6366 /* We can only change the mode of the shift if we can do arithmetic
6367 in the mode of the shift and MASK is no wider than the width of
6369 if (GET_MODE_BITSIZE (op_mode
) > HOST_BITS_PER_WIDE_INT
6370 || (mask
& ~ GET_MODE_MASK (op_mode
)) != 0)
6371 op_mode
= GET_MODE (x
);
6373 inner
= force_to_mode (inner
, op_mode
, mask
, reg
, next_select
);
6375 if (GET_MODE (x
) != op_mode
|| inner
!= XEXP (x
, 0))
6376 x
= gen_binary (LSHIFTRT
, op_mode
, inner
, XEXP (x
, 1));
6379 /* If we have (and (lshiftrt FOO C1) C2) where the combination of the
6380 shift and AND produces only copies of the sign bit (C2 is one less
6381 than a power of two), we can do this with just a shift. */
6383 if (GET_CODE (x
) == LSHIFTRT
6384 && GET_CODE (XEXP (x
, 1)) == CONST_INT
6385 && ((INTVAL (XEXP (x
, 1))
6386 + num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0))))
6387 >= GET_MODE_BITSIZE (GET_MODE (x
)))
6388 && exact_log2 (mask
+ 1) >= 0
6389 && (num_sign_bit_copies (XEXP (x
, 0), GET_MODE (XEXP (x
, 0)))
6390 >= exact_log2 (mask
+ 1)))
6391 x
= gen_binary (LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
6392 GEN_INT (GET_MODE_BITSIZE (GET_MODE (x
))
6393 - exact_log2 (mask
+ 1)));
6397 /* If we are just looking for the sign bit, we don't need this shift at
6398 all, even if it has a variable count. */
6399 if (GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
6400 && (mask
== ((HOST_WIDE_INT
) 1
6401 << (GET_MODE_BITSIZE (GET_MODE (x
)) - 1))))
6402 return force_to_mode (XEXP (x
, 0), mode
, mask
, reg
, next_select
);
6404 /* If this is a shift by a constant, get a mask that contains those bits
6405 that are not copies of the sign bit. We then have two cases: If
6406 MASK only includes those bits, this can be a logical shift, which may
6407 allow simplifications. If MASK is a single-bit field not within
6408 those bits, we are requesting a copy of the sign bit and hence can
6409 shift the sign bit to the appropriate location. */
6411 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
&& INTVAL (XEXP (x
, 1)) >= 0
6412 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
)
6416 /* If the considered data is wider then HOST_WIDE_INT, we can't
6417 represent a mask for all its bits in a single scalar.
6418 But we only care about the lower bits, so calculate these. */
6420 if (GET_MODE_BITSIZE (GET_MODE (x
)) > HOST_BITS_PER_WIDE_INT
)
6422 nonzero
= ~ (HOST_WIDE_INT
) 0;
6424 /* GET_MODE_BITSIZE (GET_MODE (x)) - INTVAL (XEXP (x, 1))
6425 is the number of bits a full-width mask would have set.
6426 We need only shift if these are fewer than nonzero can
6427 hold. If not, we must keep all bits set in nonzero. */
6429 if (GET_MODE_BITSIZE (GET_MODE (x
)) - INTVAL (XEXP (x
, 1))
6430 < HOST_BITS_PER_WIDE_INT
)
6431 nonzero
>>= INTVAL (XEXP (x
, 1))
6432 + HOST_BITS_PER_WIDE_INT
6433 - GET_MODE_BITSIZE (GET_MODE (x
)) ;
6437 nonzero
= GET_MODE_MASK (GET_MODE (x
));
6438 nonzero
>>= INTVAL (XEXP (x
, 1));
6441 if ((mask
& ~ nonzero
) == 0
6442 || (i
= exact_log2 (mask
)) >= 0)
6444 x
= simplify_shift_const
6445 (x
, LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0),
6446 i
< 0 ? INTVAL (XEXP (x
, 1))
6447 : GET_MODE_BITSIZE (GET_MODE (x
)) - 1 - i
);
6449 if (GET_CODE (x
) != ASHIFTRT
)
6450 return force_to_mode (x
, mode
, mask
, reg
, next_select
);
6454 /* If MASK is 1, convert this to a LSHIFTRT. This can be done
6455 even if the shift count isn't a constant. */
6457 x
= gen_binary (LSHIFTRT
, GET_MODE (x
), XEXP (x
, 0), XEXP (x
, 1));
6459 /* If this is a sign-extension operation that just affects bits
6460 we don't care about, remove it. Be sure the call above returned
6461 something that is still a shift. */
6463 if ((GET_CODE (x
) == LSHIFTRT
|| GET_CODE (x
) == ASHIFTRT
)
6464 && GET_CODE (XEXP (x
, 1)) == CONST_INT
6465 && INTVAL (XEXP (x
, 1)) >= 0
6466 && (INTVAL (XEXP (x
, 1))
6467 <= GET_MODE_BITSIZE (GET_MODE (x
)) - (floor_log2 (mask
) + 1))
6468 && GET_CODE (XEXP (x
, 0)) == ASHIFT
6469 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
6470 && INTVAL (XEXP (XEXP (x
, 0), 1)) == INTVAL (XEXP (x
, 1)))
6471 return force_to_mode (XEXP (XEXP (x
, 0), 0), mode
, mask
,
6478 /* If the shift count is constant and we can do computations
6479 in the mode of X, compute where the bits we care about are.
6480 Otherwise, we can't do anything. Don't change the mode of
6481 the shift or propagate MODE into the shift, though. */
6482 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
6483 && INTVAL (XEXP (x
, 1)) >= 0)
6485 temp
= simplify_binary_operation (code
== ROTATE
? ROTATERT
: ROTATE
,
6486 GET_MODE (x
), GEN_INT (mask
),
6488 if (temp
&& GET_CODE(temp
) == CONST_INT
)
6490 force_to_mode (XEXP (x
, 0), GET_MODE (x
),
6491 INTVAL (temp
), reg
, next_select
));
6496 /* If we just want the low-order bit, the NEG isn't needed since it
6497 won't change the low-order bit. */
6499 return force_to_mode (XEXP (x
, 0), mode
, mask
, reg
, just_select
);
6501 /* We need any bits less significant than the most significant bit in
6502 MASK since carries from those bits will affect the bits we are
6508 /* (not FOO) is (xor FOO CONST), so if FOO is an LSHIFTRT, we can do the
6509 same as the XOR case above. Ensure that the constant we form is not
6510 wider than the mode of X. */
6512 if (GET_CODE (XEXP (x
, 0)) == LSHIFTRT
6513 && GET_CODE (XEXP (XEXP (x
, 0), 1)) == CONST_INT
6514 && INTVAL (XEXP (XEXP (x
, 0), 1)) >= 0
6515 && (INTVAL (XEXP (XEXP (x
, 0), 1)) + floor_log2 (mask
)
6516 < GET_MODE_BITSIZE (GET_MODE (x
)))
6517 && INTVAL (XEXP (XEXP (x
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
6519 temp
= GEN_INT (mask
<< INTVAL (XEXP (XEXP (x
, 0), 1)));
6520 temp
= gen_binary (XOR
, GET_MODE (x
), XEXP (XEXP (x
, 0), 0), temp
);
6521 x
= gen_binary (LSHIFTRT
, GET_MODE (x
), temp
, XEXP (XEXP (x
, 0), 1));
6523 return force_to_mode (x
, mode
, mask
, reg
, next_select
);
6526 /* (and (not FOO) CONST) is (not (or FOO (not CONST))), so we must
6527 use the full mask inside the NOT. */
6531 op0
= gen_lowpart_for_combine (op_mode
,
6532 force_to_mode (XEXP (x
, 0), mode
, mask
,
6534 if (op_mode
!= GET_MODE (x
) || op0
!= XEXP (x
, 0))
6535 x
= gen_unary (code
, op_mode
, op_mode
, op0
);
6539 /* (and (ne FOO 0) CONST) can be (and FOO CONST) if CONST is included
6540 in STORE_FLAG_VALUE and FOO has a single bit that might be nonzero,
6541 which is equal to STORE_FLAG_VALUE. */
6542 if ((mask
& ~ STORE_FLAG_VALUE
) == 0 && XEXP (x
, 1) == const0_rtx
6543 && exact_log2 (nonzero_bits (XEXP (x
, 0), mode
)) >= 0
6544 && nonzero_bits (XEXP (x
, 0), mode
) == STORE_FLAG_VALUE
)
6545 return force_to_mode (XEXP (x
, 0), mode
, mask
, reg
, next_select
);
6550 /* We have no way of knowing if the IF_THEN_ELSE can itself be
6551 written in a narrower mode. We play it safe and do not do so. */
6554 gen_lowpart_for_combine (GET_MODE (x
),
6555 force_to_mode (XEXP (x
, 1), mode
,
6556 mask
, reg
, next_select
)));
6558 gen_lowpart_for_combine (GET_MODE (x
),
6559 force_to_mode (XEXP (x
, 2), mode
,
6560 mask
, reg
,next_select
)));
6567 /* Ensure we return a value of the proper mode. */
6568 return gen_lowpart_for_combine (mode
, x
);
6571 /* Return nonzero if X is an expression that has one of two values depending on
6572 whether some other value is zero or nonzero. In that case, we return the
6573 value that is being tested, *PTRUE is set to the value if the rtx being
6574 returned has a nonzero value, and *PFALSE is set to the other alternative.
6576 If we return zero, we set *PTRUE and *PFALSE to X. */
6579 if_then_else_cond (x
, ptrue
, pfalse
)
6581 rtx
*ptrue
, *pfalse
;
6583 enum machine_mode mode
= GET_MODE (x
);
6584 enum rtx_code code
= GET_CODE (x
);
6585 int size
= GET_MODE_BITSIZE (mode
);
6586 rtx cond0
, cond1
, true0
, true1
, false0
, false1
;
6587 unsigned HOST_WIDE_INT nz
;
6589 /* If this is a unary operation whose operand has one of two values, apply
6590 our opcode to compute those values. */
6591 if (GET_RTX_CLASS (code
) == '1'
6592 && (cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
)) != 0)
6594 *ptrue
= gen_unary (code
, mode
, GET_MODE (XEXP (x
, 0)), true0
);
6595 *pfalse
= gen_unary (code
, mode
, GET_MODE (XEXP (x
, 0)), false0
);
6599 /* If this is a COMPARE, do nothing, since the IF_THEN_ELSE we would
6600 make can't possibly match and would suppress other optimizations. */
6601 else if (code
== COMPARE
)
6604 /* If this is a binary operation, see if either side has only one of two
6605 values. If either one does or if both do and they are conditional on
6606 the same value, compute the new true and false values. */
6607 else if (GET_RTX_CLASS (code
) == 'c' || GET_RTX_CLASS (code
) == '2'
6608 || GET_RTX_CLASS (code
) == '<')
6610 cond0
= if_then_else_cond (XEXP (x
, 0), &true0
, &false0
);
6611 cond1
= if_then_else_cond (XEXP (x
, 1), &true1
, &false1
);
6613 if ((cond0
!= 0 || cond1
!= 0)
6614 && ! (cond0
!= 0 && cond1
!= 0 && ! rtx_equal_p (cond0
, cond1
)))
6616 /* If if_then_else_cond returned zero, then true/false are the
6617 same rtl. We must copy one of them to prevent invalid rtl
6620 true0
= copy_rtx (true0
);
6621 else if (cond1
== 0)
6622 true1
= copy_rtx (true1
);
6624 *ptrue
= gen_binary (code
, mode
, true0
, true1
);
6625 *pfalse
= gen_binary (code
, mode
, false0
, false1
);
6626 return cond0
? cond0
: cond1
;
6629 /* See if we have PLUS, IOR, XOR, MINUS or UMAX, where one of the
6630 operands is zero when the other is non-zero, and vice-versa,
6631 and STORE_FLAG_VALUE is 1 or -1. */
6633 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
6634 && (code
== PLUS
|| code
== IOR
|| code
== XOR
|| code
== MINUS
6636 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
6638 rtx op0
= XEXP (XEXP (x
, 0), 1);
6639 rtx op1
= XEXP (XEXP (x
, 1), 1);
6641 cond0
= XEXP (XEXP (x
, 0), 0);
6642 cond1
= XEXP (XEXP (x
, 1), 0);
6644 if (GET_RTX_CLASS (GET_CODE (cond0
)) == '<'
6645 && GET_RTX_CLASS (GET_CODE (cond1
)) == '<'
6646 && reversible_comparison_p (cond1
)
6647 && ((GET_CODE (cond0
) == reverse_condition (GET_CODE (cond1
))
6648 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
6649 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
6650 || ((swap_condition (GET_CODE (cond0
))
6651 == reverse_condition (GET_CODE (cond1
)))
6652 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
6653 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
6654 && ! side_effects_p (x
))
6656 *ptrue
= gen_binary (MULT
, mode
, op0
, const_true_rtx
);
6657 *pfalse
= gen_binary (MULT
, mode
,
6659 ? gen_unary (NEG
, mode
, mode
, op1
) : op1
),
6665 /* Similarly for MULT, AND and UMIN, execpt that for these the result
6667 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
6668 && (code
== MULT
|| code
== AND
|| code
== UMIN
)
6669 && GET_CODE (XEXP (x
, 0)) == MULT
&& GET_CODE (XEXP (x
, 1)) == MULT
)
6671 cond0
= XEXP (XEXP (x
, 0), 0);
6672 cond1
= XEXP (XEXP (x
, 1), 0);
6674 if (GET_RTX_CLASS (GET_CODE (cond0
)) == '<'
6675 && GET_RTX_CLASS (GET_CODE (cond1
)) == '<'
6676 && reversible_comparison_p (cond1
)
6677 && ((GET_CODE (cond0
) == reverse_condition (GET_CODE (cond1
))
6678 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 0))
6679 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 1)))
6680 || ((swap_condition (GET_CODE (cond0
))
6681 == reverse_condition (GET_CODE (cond1
)))
6682 && rtx_equal_p (XEXP (cond0
, 0), XEXP (cond1
, 1))
6683 && rtx_equal_p (XEXP (cond0
, 1), XEXP (cond1
, 0))))
6684 && ! side_effects_p (x
))
6686 *ptrue
= *pfalse
= const0_rtx
;
6692 else if (code
== IF_THEN_ELSE
)
6694 /* If we have IF_THEN_ELSE already, extract the condition and
6695 canonicalize it if it is NE or EQ. */
6696 cond0
= XEXP (x
, 0);
6697 *ptrue
= XEXP (x
, 1), *pfalse
= XEXP (x
, 2);
6698 if (GET_CODE (cond0
) == NE
&& XEXP (cond0
, 1) == const0_rtx
)
6699 return XEXP (cond0
, 0);
6700 else if (GET_CODE (cond0
) == EQ
&& XEXP (cond0
, 1) == const0_rtx
)
6702 *ptrue
= XEXP (x
, 2), *pfalse
= XEXP (x
, 1);
6703 return XEXP (cond0
, 0);
6709 /* If X is a normal SUBREG with both inner and outer modes integral,
6710 we can narrow both the true and false values of the inner expression,
6711 if there is a condition. */
6712 else if (code
== SUBREG
&& GET_MODE_CLASS (mode
) == MODE_INT
6713 && GET_MODE_CLASS (GET_MODE (SUBREG_REG (x
))) == MODE_INT
6714 && GET_MODE_SIZE (mode
) <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
)))
6715 && 0 != (cond0
= if_then_else_cond (SUBREG_REG (x
),
6718 *ptrue
= force_to_mode (true0
, mode
, GET_MODE_MASK (mode
), NULL_RTX
, 0);
6720 = force_to_mode (false0
, mode
, GET_MODE_MASK (mode
), NULL_RTX
, 0);
6725 /* If X is a constant, this isn't special and will cause confusions
6726 if we treat it as such. Likewise if it is equivalent to a constant. */
6727 else if (CONSTANT_P (x
)
6728 || ((cond0
= get_last_value (x
)) != 0 && CONSTANT_P (cond0
)))
6731 /* If X is known to be either 0 or -1, those are the true and
6732 false values when testing X. */
6733 else if (num_sign_bit_copies (x
, mode
) == size
)
6735 *ptrue
= constm1_rtx
, *pfalse
= const0_rtx
;
6739 /* Likewise for 0 or a single bit. */
6740 else if (exact_log2 (nz
= nonzero_bits (x
, mode
)) >= 0)
6742 *ptrue
= GEN_INT (nz
), *pfalse
= const0_rtx
;
6746 /* Otherwise fail; show no condition with true and false values the same. */
6747 *ptrue
= *pfalse
= x
;
6751 /* Return the value of expression X given the fact that condition COND
6752 is known to be true when applied to REG as its first operand and VAL
6753 as its second. X is known to not be shared and so can be modified in
6756 We only handle the simplest cases, and specifically those cases that
6757 arise with IF_THEN_ELSE expressions. */
6760 known_cond (x
, cond
, reg
, val
)
6765 enum rtx_code code
= GET_CODE (x
);
6770 if (side_effects_p (x
))
6773 if (cond
== EQ
&& rtx_equal_p (x
, reg
))
6776 /* If X is (abs REG) and we know something about REG's relationship
6777 with zero, we may be able to simplify this. */
6779 if (code
== ABS
&& rtx_equal_p (XEXP (x
, 0), reg
) && val
== const0_rtx
)
6782 case GE
: case GT
: case EQ
:
6785 return gen_unary (NEG
, GET_MODE (XEXP (x
, 0)), GET_MODE (XEXP (x
, 0)),
6791 /* The only other cases we handle are MIN, MAX, and comparisons if the
6792 operands are the same as REG and VAL. */
6794 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == 'c')
6796 if (rtx_equal_p (XEXP (x
, 0), val
))
6797 cond
= swap_condition (cond
), temp
= val
, val
= reg
, reg
= temp
;
6799 if (rtx_equal_p (XEXP (x
, 0), reg
) && rtx_equal_p (XEXP (x
, 1), val
))
6801 if (GET_RTX_CLASS (code
) == '<')
6802 return (comparison_dominates_p (cond
, code
) ? const_true_rtx
6803 : (comparison_dominates_p (cond
,
6804 reverse_condition (code
))
6807 else if (code
== SMAX
|| code
== SMIN
6808 || code
== UMIN
|| code
== UMAX
)
6810 int unsignedp
= (code
== UMIN
|| code
== UMAX
);
6812 if (code
== SMAX
|| code
== UMAX
)
6813 cond
= reverse_condition (cond
);
6818 return unsignedp
? x
: XEXP (x
, 1);
6820 return unsignedp
? x
: XEXP (x
, 0);
6822 return unsignedp
? XEXP (x
, 1) : x
;
6824 return unsignedp
? XEXP (x
, 0) : x
;
6832 fmt
= GET_RTX_FORMAT (code
);
6833 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
6836 SUBST (XEXP (x
, i
), known_cond (XEXP (x
, i
), cond
, reg
, val
));
6837 else if (fmt
[i
] == 'E')
6838 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
6839 SUBST (XVECEXP (x
, i
, j
), known_cond (XVECEXP (x
, i
, j
),
6846 /* See if X and Y are equal for the purposes of seeing if we can rewrite an
6847 assignment as a field assignment. */
6850 rtx_equal_for_field_assignment_p (x
, y
)
6856 if (x
== y
|| rtx_equal_p (x
, y
))
6859 if (x
== 0 || y
== 0 || GET_MODE (x
) != GET_MODE (y
))
6862 /* Check for a paradoxical SUBREG of a MEM compared with the MEM.
6863 Note that all SUBREGs of MEM are paradoxical; otherwise they
6864 would have been rewritten. */
6865 if (GET_CODE (x
) == MEM
&& GET_CODE (y
) == SUBREG
6866 && GET_CODE (SUBREG_REG (y
)) == MEM
6867 && rtx_equal_p (SUBREG_REG (y
),
6868 gen_lowpart_for_combine (GET_MODE (SUBREG_REG (y
)), x
)))
6871 if (GET_CODE (y
) == MEM
&& GET_CODE (x
) == SUBREG
6872 && GET_CODE (SUBREG_REG (x
)) == MEM
6873 && rtx_equal_p (SUBREG_REG (x
),
6874 gen_lowpart_for_combine (GET_MODE (SUBREG_REG (x
)), y
)))
6877 last_x
= get_last_value (x
);
6878 last_y
= get_last_value (y
);
6880 return ((last_x
!= 0
6881 && GET_CODE (last_x
) != CLOBBER
6882 && rtx_equal_for_field_assignment_p (last_x
, y
))
6884 && GET_CODE (last_y
) != CLOBBER
6885 && rtx_equal_for_field_assignment_p (x
, last_y
))
6886 || (last_x
!= 0 && last_y
!= 0
6887 && GET_CODE (last_x
) != CLOBBER
6888 && GET_CODE (last_y
) != CLOBBER
6889 && rtx_equal_for_field_assignment_p (last_x
, last_y
)));
6892 /* See if X, a SET operation, can be rewritten as a bit-field assignment.
6893 Return that assignment if so.
6895 We only handle the most common cases. */
6898 make_field_assignment (x
)
6901 rtx dest
= SET_DEST (x
);
6902 rtx src
= SET_SRC (x
);
6908 enum machine_mode mode
;
6910 /* If SRC was (and (not (ashift (const_int 1) POS)) DEST), this is
6911 a clear of a one-bit field. We will have changed it to
6912 (and (rotate (const_int -2) POS) DEST), so check for that. Also check
6915 if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == ROTATE
6916 && GET_CODE (XEXP (XEXP (src
, 0), 0)) == CONST_INT
6917 && INTVAL (XEXP (XEXP (src
, 0), 0)) == -2
6918 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
6920 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
6923 return gen_rtx (SET
, VOIDmode
, assign
, const0_rtx
);
6927 else if (GET_CODE (src
) == AND
&& GET_CODE (XEXP (src
, 0)) == SUBREG
6928 && subreg_lowpart_p (XEXP (src
, 0))
6929 && (GET_MODE_SIZE (GET_MODE (XEXP (src
, 0)))
6930 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (src
, 0)))))
6931 && GET_CODE (SUBREG_REG (XEXP (src
, 0))) == ROTATE
6932 && INTVAL (XEXP (SUBREG_REG (XEXP (src
, 0)), 0)) == -2
6933 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
6935 assign
= make_extraction (VOIDmode
, dest
, 0,
6936 XEXP (SUBREG_REG (XEXP (src
, 0)), 1),
6939 return gen_rtx (SET
, VOIDmode
, assign
, const0_rtx
);
6943 /* If SRC is (ior (ashift (const_int 1) POS) DEST), this is a set of a
6945 else if (GET_CODE (src
) == IOR
&& GET_CODE (XEXP (src
, 0)) == ASHIFT
6946 && XEXP (XEXP (src
, 0), 0) == const1_rtx
6947 && rtx_equal_for_field_assignment_p (dest
, XEXP (src
, 1)))
6949 assign
= make_extraction (VOIDmode
, dest
, 0, XEXP (XEXP (src
, 0), 1),
6952 return gen_rtx (SET
, VOIDmode
, assign
, const1_rtx
);
6956 /* The other case we handle is assignments into a constant-position
6957 field. They look like (ior/xor (and DEST C1) OTHER). If C1 represents
6958 a mask that has all one bits except for a group of zero bits and
6959 OTHER is known to have zeros where C1 has ones, this is such an
6960 assignment. Compute the position and length from C1. Shift OTHER
6961 to the appropriate position, force it to the required mode, and
6962 make the extraction. Check for the AND in both operands. */
6964 if (GET_CODE (src
) != IOR
&& GET_CODE (src
) != XOR
)
6967 rhs
= expand_compound_operation (XEXP (src
, 0));
6968 lhs
= expand_compound_operation (XEXP (src
, 1));
6970 if (GET_CODE (rhs
) == AND
6971 && GET_CODE (XEXP (rhs
, 1)) == CONST_INT
6972 && rtx_equal_for_field_assignment_p (XEXP (rhs
, 0), dest
))
6973 c1
= INTVAL (XEXP (rhs
, 1)), other
= lhs
;
6974 else if (GET_CODE (lhs
) == AND
6975 && GET_CODE (XEXP (lhs
, 1)) == CONST_INT
6976 && rtx_equal_for_field_assignment_p (XEXP (lhs
, 0), dest
))
6977 c1
= INTVAL (XEXP (lhs
, 1)), other
= rhs
;
6981 pos
= get_pos_from_mask ((~ c1
) & GET_MODE_MASK (GET_MODE (dest
)), &len
);
6982 if (pos
< 0 || pos
+ len
> GET_MODE_BITSIZE (GET_MODE (dest
))
6983 || (GET_MODE_BITSIZE (GET_MODE (other
)) <= HOST_BITS_PER_WIDE_INT
6984 && (c1
& nonzero_bits (other
, GET_MODE (other
))) != 0))
6987 assign
= make_extraction (VOIDmode
, dest
, pos
, NULL_RTX
, len
, 1, 1, 0);
6991 /* The mode to use for the source is the mode of the assignment, or of
6992 what is inside a possible STRICT_LOW_PART. */
6993 mode
= (GET_CODE (assign
) == STRICT_LOW_PART
6994 ? GET_MODE (XEXP (assign
, 0)) : GET_MODE (assign
));
6996 /* Shift OTHER right POS places and make it the source, restricting it
6997 to the proper length and mode. */
6999 src
= force_to_mode (simplify_shift_const (NULL_RTX
, LSHIFTRT
,
7000 GET_MODE (src
), other
, pos
),
7002 GET_MODE_BITSIZE (mode
) >= HOST_BITS_PER_WIDE_INT
7003 ? GET_MODE_MASK (mode
)
7004 : ((HOST_WIDE_INT
) 1 << len
) - 1,
7007 return gen_rtx_combine (SET
, VOIDmode
, assign
, src
);
7010 /* See if X is of the form (+ (* a c) (* b c)) and convert to (* (+ a b) c)
7014 apply_distributive_law (x
)
7017 enum rtx_code code
= GET_CODE (x
);
7018 rtx lhs
, rhs
, other
;
7020 enum rtx_code inner_code
;
7022 /* Distributivity is not true for floating point.
7023 It can change the value. So don't do it.
7024 -- rms and moshier@world.std.com. */
7025 if (FLOAT_MODE_P (GET_MODE (x
)))
7028 /* The outer operation can only be one of the following: */
7029 if (code
!= IOR
&& code
!= AND
&& code
!= XOR
7030 && code
!= PLUS
&& code
!= MINUS
)
7033 lhs
= XEXP (x
, 0), rhs
= XEXP (x
, 1);
7035 /* If either operand is a primitive we can't do anything, so get out
7037 if (GET_RTX_CLASS (GET_CODE (lhs
)) == 'o'
7038 || GET_RTX_CLASS (GET_CODE (rhs
)) == 'o')
7041 lhs
= expand_compound_operation (lhs
);
7042 rhs
= expand_compound_operation (rhs
);
7043 inner_code
= GET_CODE (lhs
);
7044 if (inner_code
!= GET_CODE (rhs
))
7047 /* See if the inner and outer operations distribute. */
7054 /* These all distribute except over PLUS. */
7055 if (code
== PLUS
|| code
== MINUS
)
7060 if (code
!= PLUS
&& code
!= MINUS
)
7065 /* This is also a multiply, so it distributes over everything. */
7069 /* Non-paradoxical SUBREGs distributes over all operations, provided
7070 the inner modes and word numbers are the same, this is an extraction
7071 of a low-order part, we don't convert an fp operation to int or
7072 vice versa, and we would not be converting a single-word
7073 operation into a multi-word operation. The latter test is not
7074 required, but it prevents generating unneeded multi-word operations.
7075 Some of the previous tests are redundant given the latter test, but
7076 are retained because they are required for correctness.
7078 We produce the result slightly differently in this case. */
7080 if (GET_MODE (SUBREG_REG (lhs
)) != GET_MODE (SUBREG_REG (rhs
))
7081 || SUBREG_WORD (lhs
) != SUBREG_WORD (rhs
)
7082 || ! subreg_lowpart_p (lhs
)
7083 || (GET_MODE_CLASS (GET_MODE (lhs
))
7084 != GET_MODE_CLASS (GET_MODE (SUBREG_REG (lhs
))))
7085 || (GET_MODE_SIZE (GET_MODE (lhs
))
7086 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs
))))
7087 || GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs
))) > UNITS_PER_WORD
)
7090 tem
= gen_binary (code
, GET_MODE (SUBREG_REG (lhs
)),
7091 SUBREG_REG (lhs
), SUBREG_REG (rhs
));
7092 return gen_lowpart_for_combine (GET_MODE (x
), tem
);
7098 /* Set LHS and RHS to the inner operands (A and B in the example
7099 above) and set OTHER to the common operand (C in the example).
7100 These is only one way to do this unless the inner operation is
7102 if (GET_RTX_CLASS (inner_code
) == 'c'
7103 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 0)))
7104 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 1);
7105 else if (GET_RTX_CLASS (inner_code
) == 'c'
7106 && rtx_equal_p (XEXP (lhs
, 0), XEXP (rhs
, 1)))
7107 other
= XEXP (lhs
, 0), lhs
= XEXP (lhs
, 1), rhs
= XEXP (rhs
, 0);
7108 else if (GET_RTX_CLASS (inner_code
) == 'c'
7109 && rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 0)))
7110 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 1);
7111 else if (rtx_equal_p (XEXP (lhs
, 1), XEXP (rhs
, 1)))
7112 other
= XEXP (lhs
, 1), lhs
= XEXP (lhs
, 0), rhs
= XEXP (rhs
, 0);
7116 /* Form the new inner operation, seeing if it simplifies first. */
7117 tem
= gen_binary (code
, GET_MODE (x
), lhs
, rhs
);
7119 /* There is one exception to the general way of distributing:
7120 (a ^ b) | (a ^ c) -> (~a) & (b ^ c) */
7121 if (code
== XOR
&& inner_code
== IOR
)
7124 other
= gen_unary (NOT
, GET_MODE (x
), GET_MODE (x
), other
);
7127 /* We may be able to continuing distributing the result, so call
7128 ourselves recursively on the inner operation before forming the
7129 outer operation, which we return. */
7130 return gen_binary (inner_code
, GET_MODE (x
),
7131 apply_distributive_law (tem
), other
);
7134 /* We have X, a logical `and' of VAROP with the constant CONSTOP, to be done
7137 Return an equivalent form, if different from X. Otherwise, return X. If
7138 X is zero, we are to always construct the equivalent form. */
7141 simplify_and_const_int (x
, mode
, varop
, constop
)
7143 enum machine_mode mode
;
7145 unsigned HOST_WIDE_INT constop
;
7147 unsigned HOST_WIDE_INT nonzero
;
7148 int width
= GET_MODE_BITSIZE (mode
);
7151 /* Simplify VAROP knowing that we will be only looking at some of the
7153 varop
= force_to_mode (varop
, mode
, constop
, NULL_RTX
, 0);
7155 /* If VAROP is a CLOBBER, we will fail so return it; if it is a
7156 CONST_INT, we are done. */
7157 if (GET_CODE (varop
) == CLOBBER
|| GET_CODE (varop
) == CONST_INT
)
7160 /* See what bits may be nonzero in VAROP. Unlike the general case of
7161 a call to nonzero_bits, here we don't care about bits outside
7164 nonzero
= nonzero_bits (varop
, mode
) & GET_MODE_MASK (mode
);
7166 /* If this would be an entire word for the target, but is not for
7167 the host, then sign-extend on the host so that the number will look
7168 the same way on the host that it would on the target.
7170 For example, when building a 64 bit alpha hosted 32 bit sparc
7171 targeted compiler, then we want the 32 bit unsigned value -1 to be
7172 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
7173 The later confuses the sparc backend. */
7175 if (BITS_PER_WORD
< HOST_BITS_PER_WIDE_INT
&& BITS_PER_WORD
== width
7176 && (nonzero
& ((HOST_WIDE_INT
) 1 << (width
- 1))))
7177 nonzero
|= ((HOST_WIDE_INT
) (-1) << width
);
7179 /* Turn off all bits in the constant that are known to already be zero.
7180 Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS
7181 which is tested below. */
7185 /* If we don't have any bits left, return zero. */
7189 /* If VAROP is a NEG of something known to be zero or 1 and CONSTOP is
7190 a power of two, we can replace this with a ASHIFT. */
7191 if (GET_CODE (varop
) == NEG
&& nonzero_bits (XEXP (varop
, 0), mode
) == 1
7192 && (i
= exact_log2 (constop
)) >= 0)
7193 return simplify_shift_const (NULL_RTX
, ASHIFT
, mode
, XEXP (varop
, 0), i
);
7195 /* If VAROP is an IOR or XOR, apply the AND to both branches of the IOR
7196 or XOR, then try to apply the distributive law. This may eliminate
7197 operations if either branch can be simplified because of the AND.
7198 It may also make some cases more complex, but those cases probably
7199 won't match a pattern either with or without this. */
7201 if (GET_CODE (varop
) == IOR
|| GET_CODE (varop
) == XOR
)
7203 gen_lowpart_for_combine
7205 apply_distributive_law
7206 (gen_binary (GET_CODE (varop
), GET_MODE (varop
),
7207 simplify_and_const_int (NULL_RTX
, GET_MODE (varop
),
7208 XEXP (varop
, 0), constop
),
7209 simplify_and_const_int (NULL_RTX
, GET_MODE (varop
),
7210 XEXP (varop
, 1), constop
))));
7212 /* Get VAROP in MODE. Try to get a SUBREG if not. Don't make a new SUBREG
7213 if we already had one (just check for the simplest cases). */
7214 if (x
&& GET_CODE (XEXP (x
, 0)) == SUBREG
7215 && GET_MODE (XEXP (x
, 0)) == mode
7216 && SUBREG_REG (XEXP (x
, 0)) == varop
)
7217 varop
= XEXP (x
, 0);
7219 varop
= gen_lowpart_for_combine (mode
, varop
);
7221 /* If we can't make the SUBREG, try to return what we were given. */
7222 if (GET_CODE (varop
) == CLOBBER
)
7223 return x
? x
: varop
;
7225 /* If we are only masking insignificant bits, return VAROP. */
7226 if (constop
== nonzero
)
7229 /* Otherwise, return an AND. See how much, if any, of X we can use. */
7230 else if (x
== 0 || GET_CODE (x
) != AND
|| GET_MODE (x
) != mode
)
7231 x
= gen_binary (AND
, mode
, varop
, GEN_INT (constop
));
7235 if (GET_CODE (XEXP (x
, 1)) != CONST_INT
7236 || INTVAL (XEXP (x
, 1)) != constop
)
7237 SUBST (XEXP (x
, 1), GEN_INT (constop
));
7239 SUBST (XEXP (x
, 0), varop
);
7245 /* We let num_sign_bit_copies recur into nonzero_bits as that is useful.
7246 We don't let nonzero_bits recur into num_sign_bit_copies, because that
7247 is less useful. We can't allow both, because that results in exponential
7248 run time recursion. There is a nullstone testcase that triggered
7249 this. This macro avoids accidental uses of num_sign_bit_copies. */
7250 #define num_sign_bit_copies()
7252 /* Given an expression, X, compute which bits in X can be non-zero.
7253 We don't care about bits outside of those defined in MODE.
7255 For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
7256 a shift, AND, or zero_extract, we can do better. */
7258 static unsigned HOST_WIDE_INT
7259 nonzero_bits (x
, mode
)
7261 enum machine_mode mode
;
7263 unsigned HOST_WIDE_INT nonzero
= GET_MODE_MASK (mode
);
7264 unsigned HOST_WIDE_INT inner_nz
;
7266 int mode_width
= GET_MODE_BITSIZE (mode
);
7269 /* For floating-point values, assume all bits are needed. */
7270 if (FLOAT_MODE_P (GET_MODE (x
)) || FLOAT_MODE_P (mode
))
7273 /* If X is wider than MODE, use its mode instead. */
7274 if (GET_MODE_BITSIZE (GET_MODE (x
)) > mode_width
)
7276 mode
= GET_MODE (x
);
7277 nonzero
= GET_MODE_MASK (mode
);
7278 mode_width
= GET_MODE_BITSIZE (mode
);
7281 if (mode_width
> HOST_BITS_PER_WIDE_INT
)
7282 /* Our only callers in this case look for single bit values. So
7283 just return the mode mask. Those tests will then be false. */
7286 #ifndef WORD_REGISTER_OPERATIONS
7287 /* If MODE is wider than X, but both are a single word for both the host
7288 and target machines, we can compute this from which bits of the
7289 object might be nonzero in its own mode, taking into account the fact
7290 that on many CISC machines, accessing an object in a wider mode
7291 causes the high-order bits to become undefined. So they are
7292 not known to be zero. */
7294 if (GET_MODE (x
) != VOIDmode
&& GET_MODE (x
) != mode
7295 && GET_MODE_BITSIZE (GET_MODE (x
)) <= BITS_PER_WORD
7296 && GET_MODE_BITSIZE (GET_MODE (x
)) <= HOST_BITS_PER_WIDE_INT
7297 && GET_MODE_BITSIZE (mode
) > GET_MODE_BITSIZE (GET_MODE (x
)))
7299 nonzero
&= nonzero_bits (x
, GET_MODE (x
));
7300 nonzero
|= GET_MODE_MASK (mode
) & ~ GET_MODE_MASK (GET_MODE (x
));
7305 code
= GET_CODE (x
);
7309 #ifdef POINTERS_EXTEND_UNSIGNED
7310 /* If pointers extend unsigned and this is a pointer in Pmode, say that
7311 all the bits above ptr_mode are known to be zero. */
7312 if (POINTERS_EXTEND_UNSIGNED
&& GET_MODE (x
) == Pmode
7313 && REGNO_POINTER_FLAG (REGNO (x
)))
7314 nonzero
&= GET_MODE_MASK (ptr_mode
);
7317 #ifdef STACK_BOUNDARY
7318 /* If this is the stack pointer, we may know something about its
7319 alignment. If PUSH_ROUNDING is defined, it is possible for the
7320 stack to be momentarily aligned only to that amount, so we pick
7321 the least alignment. */
7323 /* We can't check for arg_pointer_rtx here, because it is not
7324 guaranteed to have as much alignment as the stack pointer.
7325 In particular, in the Irix6 n64 ABI, the stack has 128 bit
7326 alignment but the argument pointer has only 64 bit alignment. */
7328 if (x
== stack_pointer_rtx
|| x
== frame_pointer_rtx
7329 || x
== hard_frame_pointer_rtx
7330 || (REGNO (x
) >= FIRST_VIRTUAL_REGISTER
7331 && REGNO (x
) <= LAST_VIRTUAL_REGISTER
))
7333 int sp_alignment
= STACK_BOUNDARY
/ BITS_PER_UNIT
;
7335 #ifdef PUSH_ROUNDING
7336 if (REGNO (x
) == STACK_POINTER_REGNUM
)
7337 sp_alignment
= MIN (PUSH_ROUNDING (1), sp_alignment
);
7340 /* We must return here, otherwise we may get a worse result from
7341 one of the choices below. There is nothing useful below as
7342 far as the stack pointer is concerned. */
7343 return nonzero
&= ~ (sp_alignment
- 1);
7347 /* If X is a register whose nonzero bits value is current, use it.
7348 Otherwise, if X is a register whose value we can find, use that
7349 value. Otherwise, use the previously-computed global nonzero bits
7350 for this register. */
7352 if (reg_last_set_value
[REGNO (x
)] != 0
7353 && reg_last_set_mode
[REGNO (x
)] == mode
7354 && (REG_N_SETS (REGNO (x
)) == 1
7355 || reg_last_set_label
[REGNO (x
)] == label_tick
)
7356 && INSN_CUID (reg_last_set
[REGNO (x
)]) < subst_low_cuid
)
7357 return reg_last_set_nonzero_bits
[REGNO (x
)];
7359 tem
= get_last_value (x
);
7363 #ifdef SHORT_IMMEDIATES_SIGN_EXTEND
7364 /* If X is narrower than MODE and TEM is a non-negative
7365 constant that would appear negative in the mode of X,
7366 sign-extend it for use in reg_nonzero_bits because some
7367 machines (maybe most) will actually do the sign-extension
7368 and this is the conservative approach.
7370 ??? For 2.5, try to tighten up the MD files in this regard
7371 instead of this kludge. */
7373 if (GET_MODE_BITSIZE (GET_MODE (x
)) < mode_width
7374 && GET_CODE (tem
) == CONST_INT
7376 && 0 != (INTVAL (tem
)
7377 & ((HOST_WIDE_INT
) 1
7378 << (GET_MODE_BITSIZE (GET_MODE (x
)) - 1))))
7379 tem
= GEN_INT (INTVAL (tem
)
7380 | ((HOST_WIDE_INT
) (-1)
7381 << GET_MODE_BITSIZE (GET_MODE (x
))));
7383 return nonzero_bits (tem
, mode
);
7385 else if (nonzero_sign_valid
&& reg_nonzero_bits
[REGNO (x
)])
7386 return reg_nonzero_bits
[REGNO (x
)] & nonzero
;
7391 #ifdef SHORT_IMMEDIATES_SIGN_EXTEND
7392 /* If X is negative in MODE, sign-extend the value. */
7393 if (INTVAL (x
) > 0 && mode_width
< BITS_PER_WORD
7394 && 0 != (INTVAL (x
) & ((HOST_WIDE_INT
) 1 << (mode_width
- 1))))
7395 return (INTVAL (x
) | ((HOST_WIDE_INT
) (-1) << mode_width
));
7401 #ifdef LOAD_EXTEND_OP
7402 /* In many, if not most, RISC machines, reading a byte from memory
7403 zeros the rest of the register. Noticing that fact saves a lot
7404 of extra zero-extends. */
7405 if (LOAD_EXTEND_OP (GET_MODE (x
)) == ZERO_EXTEND
)
7406 nonzero
&= GET_MODE_MASK (GET_MODE (x
));
7416 /* If this produces an integer result, we know which bits are set.
7417 Code here used to clear bits outside the mode of X, but that is
7420 if (GET_MODE_CLASS (mode
) == MODE_INT
7421 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
7422 nonzero
= STORE_FLAG_VALUE
;
7427 /* Disabled to avoid exponential mutual recursion between nonzero_bits
7428 and num_sign_bit_copies. */
7429 if (num_sign_bit_copies (XEXP (x
, 0), GET_MODE (x
))
7430 == GET_MODE_BITSIZE (GET_MODE (x
)))
7434 if (GET_MODE_SIZE (GET_MODE (x
)) < mode_width
)
7435 nonzero
|= (GET_MODE_MASK (mode
) & ~ GET_MODE_MASK (GET_MODE (x
)));
7440 /* Disabled to avoid exponential mutual recursion between nonzero_bits
7441 and num_sign_bit_copies. */
7442 if (num_sign_bit_copies (XEXP (x
, 0), GET_MODE (x
))
7443 == GET_MODE_BITSIZE (GET_MODE (x
)))
7449 nonzero
&= (nonzero_bits (XEXP (x
, 0), mode
) & GET_MODE_MASK (mode
));
7453 nonzero
&= nonzero_bits (XEXP (x
, 0), mode
);
7454 if (GET_MODE (XEXP (x
, 0)) != VOIDmode
)
7455 nonzero
&= GET_MODE_MASK (GET_MODE (XEXP (x
, 0)));
7459 /* If the sign bit is known clear, this is the same as ZERO_EXTEND.
7460 Otherwise, show all the bits in the outer mode but not the inner
7462 inner_nz
= nonzero_bits (XEXP (x
, 0), mode
);
7463 if (GET_MODE (XEXP (x
, 0)) != VOIDmode
)
7465 inner_nz
&= GET_MODE_MASK (GET_MODE (XEXP (x
, 0)));
7467 & (((HOST_WIDE_INT
) 1
7468 << (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0))) - 1))))
7469 inner_nz
|= (GET_MODE_MASK (mode
)
7470 & ~ GET_MODE_MASK (GET_MODE (XEXP (x
, 0))));
7473 nonzero
&= inner_nz
;
7477 nonzero
&= (nonzero_bits (XEXP (x
, 0), mode
)
7478 & nonzero_bits (XEXP (x
, 1), mode
));
7482 case UMIN
: case UMAX
: case SMIN
: case SMAX
:
7483 nonzero
&= (nonzero_bits (XEXP (x
, 0), mode
)
7484 | nonzero_bits (XEXP (x
, 1), mode
));
7487 case PLUS
: case MINUS
:
7489 case DIV
: case UDIV
:
7490 case MOD
: case UMOD
:
7491 /* We can apply the rules of arithmetic to compute the number of
7492 high- and low-order zero bits of these operations. We start by
7493 computing the width (position of the highest-order non-zero bit)
7494 and the number of low-order zero bits for each value. */
7496 unsigned HOST_WIDE_INT nz0
= nonzero_bits (XEXP (x
, 0), mode
);
7497 unsigned HOST_WIDE_INT nz1
= nonzero_bits (XEXP (x
, 1), mode
);
7498 int width0
= floor_log2 (nz0
) + 1;
7499 int width1
= floor_log2 (nz1
) + 1;
7500 int low0
= floor_log2 (nz0
& -nz0
);
7501 int low1
= floor_log2 (nz1
& -nz1
);
7502 HOST_WIDE_INT op0_maybe_minusp
7503 = (nz0
& ((HOST_WIDE_INT
) 1 << (mode_width
- 1)));
7504 HOST_WIDE_INT op1_maybe_minusp
7505 = (nz1
& ((HOST_WIDE_INT
) 1 << (mode_width
- 1)));
7506 int result_width
= mode_width
;
7512 result_width
= MAX (width0
, width1
) + 1;
7513 result_low
= MIN (low0
, low1
);
7516 result_low
= MIN (low0
, low1
);
7519 result_width
= width0
+ width1
;
7520 result_low
= low0
+ low1
;
7523 if (! op0_maybe_minusp
&& ! op1_maybe_minusp
)
7524 result_width
= width0
;
7527 result_width
= width0
;
7530 if (! op0_maybe_minusp
&& ! op1_maybe_minusp
)
7531 result_width
= MIN (width0
, width1
);
7532 result_low
= MIN (low0
, low1
);
7535 result_width
= MIN (width0
, width1
);
7536 result_low
= MIN (low0
, low1
);
7542 if (result_width
< mode_width
)
7543 nonzero
&= ((HOST_WIDE_INT
) 1 << result_width
) - 1;
7546 nonzero
&= ~ (((HOST_WIDE_INT
) 1 << result_low
) - 1);
7551 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
7552 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
)
7553 nonzero
&= ((HOST_WIDE_INT
) 1 << INTVAL (XEXP (x
, 1))) - 1;
7557 /* If this is a SUBREG formed for a promoted variable that has
7558 been zero-extended, we know that at least the high-order bits
7559 are zero, though others might be too. */
7561 if (SUBREG_PROMOTED_VAR_P (x
) && SUBREG_PROMOTED_UNSIGNED_P (x
))
7562 nonzero
= (GET_MODE_MASK (GET_MODE (x
))
7563 & nonzero_bits (SUBREG_REG (x
), GET_MODE (x
)));
7565 /* If the inner mode is a single word for both the host and target
7566 machines, we can compute this from which bits of the inner
7567 object might be nonzero. */
7568 if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x
))) <= BITS_PER_WORD
7569 && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x
)))
7570 <= HOST_BITS_PER_WIDE_INT
))
7572 nonzero
&= nonzero_bits (SUBREG_REG (x
), mode
);
7574 #ifndef WORD_REGISTER_OPERATIONS
7575 /* On many CISC machines, accessing an object in a wider mode
7576 causes the high-order bits to become undefined. So they are
7577 not known to be zero. */
7578 if (GET_MODE_SIZE (GET_MODE (x
))
7579 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
7580 nonzero
|= (GET_MODE_MASK (GET_MODE (x
))
7581 & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x
))));
7590 /* The nonzero bits are in two classes: any bits within MODE
7591 that aren't in GET_MODE (x) are always significant. The rest of the
7592 nonzero bits are those that are significant in the operand of
7593 the shift when shifted the appropriate number of bits. This
7594 shows that high-order bits are cleared by the right shift and
7595 low-order bits by left shifts. */
7596 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
7597 && INTVAL (XEXP (x
, 1)) >= 0
7598 && INTVAL (XEXP (x
, 1)) < HOST_BITS_PER_WIDE_INT
)
7600 enum machine_mode inner_mode
= GET_MODE (x
);
7601 int width
= GET_MODE_BITSIZE (inner_mode
);
7602 int count
= INTVAL (XEXP (x
, 1));
7603 unsigned HOST_WIDE_INT mode_mask
= GET_MODE_MASK (inner_mode
);
7604 unsigned HOST_WIDE_INT op_nonzero
= nonzero_bits (XEXP (x
, 0), mode
);
7605 unsigned HOST_WIDE_INT inner
= op_nonzero
& mode_mask
;
7606 unsigned HOST_WIDE_INT outer
= 0;
7608 if (mode_width
> width
)
7609 outer
= (op_nonzero
& nonzero
& ~ mode_mask
);
7611 if (code
== LSHIFTRT
)
7613 else if (code
== ASHIFTRT
)
7617 /* If the sign bit may have been nonzero before the shift, we
7618 need to mark all the places it could have been copied to
7619 by the shift as possibly nonzero. */
7620 if (inner
& ((HOST_WIDE_INT
) 1 << (width
- 1 - count
)))
7621 inner
|= (((HOST_WIDE_INT
) 1 << count
) - 1) << (width
- count
);
7623 else if (code
== ASHIFT
)
7626 inner
= ((inner
<< (count
% width
)
7627 | (inner
>> (width
- (count
% width
)))) & mode_mask
);
7629 nonzero
&= (outer
| inner
);
7634 /* This is at most the number of bits in the mode. */
7635 nonzero
= ((HOST_WIDE_INT
) 1 << (floor_log2 (mode_width
) + 1)) - 1;
7639 nonzero
&= (nonzero_bits (XEXP (x
, 1), mode
)
7640 | nonzero_bits (XEXP (x
, 2), mode
));
7650 /* See the macro definition above. */
7651 #undef num_sign_bit_copies
7653 /* Return the number of bits at the high-order end of X that are known to
7654 be equal to the sign bit. X will be used in mode MODE; if MODE is
7655 VOIDmode, X will be used in its own mode. The returned value will always
7656 be between 1 and the number of bits in MODE. */
7659 num_sign_bit_copies (x
, mode
)
7661 enum machine_mode mode
;
7663 enum rtx_code code
= GET_CODE (x
);
7665 int num0
, num1
, result
;
7666 unsigned HOST_WIDE_INT nonzero
;
7669 /* If we weren't given a mode, use the mode of X. If the mode is still
7670 VOIDmode, we don't know anything. Likewise if one of the modes is
7673 if (mode
== VOIDmode
)
7674 mode
= GET_MODE (x
);
7676 if (mode
== VOIDmode
|| FLOAT_MODE_P (mode
) || FLOAT_MODE_P (GET_MODE (x
)))
7679 bitwidth
= GET_MODE_BITSIZE (mode
);
7681 /* For a smaller object, just ignore the high bits. */
7682 if (bitwidth
< GET_MODE_BITSIZE (GET_MODE (x
)))
7683 return MAX (1, (num_sign_bit_copies (x
, GET_MODE (x
))
7684 - (GET_MODE_BITSIZE (GET_MODE (x
)) - bitwidth
)));
7686 if (GET_MODE (x
) != VOIDmode
&& bitwidth
> GET_MODE_BITSIZE (GET_MODE (x
)))
7688 #ifndef WORD_REGISTER_OPERATIONS
7689 /* If this machine does not do all register operations on the entire
7690 register and MODE is wider than the mode of X, we can say nothing
7691 at all about the high-order bits. */
7694 /* Likewise on machines that do, if the mode of the object is smaller
7695 than a word and loads of that size don't sign extend, we can say
7696 nothing about the high order bits. */
7697 if (GET_MODE_BITSIZE (GET_MODE (x
)) < BITS_PER_WORD
7698 #ifdef LOAD_EXTEND_OP
7699 && LOAD_EXTEND_OP (GET_MODE (x
)) != SIGN_EXTEND
7710 #ifdef POINTERS_EXTEND_UNSIGNED
7711 /* If pointers extend signed and this is a pointer in Pmode, say that
7712 all the bits above ptr_mode are known to be sign bit copies. */
7713 if (! POINTERS_EXTEND_UNSIGNED
&& GET_MODE (x
) == Pmode
&& mode
== Pmode
7714 && REGNO_POINTER_FLAG (REGNO (x
)))
7715 return GET_MODE_BITSIZE (Pmode
) - GET_MODE_BITSIZE (ptr_mode
) + 1;
7718 if (reg_last_set_value
[REGNO (x
)] != 0
7719 && reg_last_set_mode
[REGNO (x
)] == mode
7720 && (REG_N_SETS (REGNO (x
)) == 1
7721 || reg_last_set_label
[REGNO (x
)] == label_tick
)
7722 && INSN_CUID (reg_last_set
[REGNO (x
)]) < subst_low_cuid
)
7723 return reg_last_set_sign_bit_copies
[REGNO (x
)];
7725 tem
= get_last_value (x
);
7727 return num_sign_bit_copies (tem
, mode
);
7729 if (nonzero_sign_valid
&& reg_sign_bit_copies
[REGNO (x
)] != 0)
7730 return reg_sign_bit_copies
[REGNO (x
)];
7734 #ifdef LOAD_EXTEND_OP
7735 /* Some RISC machines sign-extend all loads of smaller than a word. */
7736 if (LOAD_EXTEND_OP (GET_MODE (x
)) == SIGN_EXTEND
)
7737 return MAX (1, bitwidth
- GET_MODE_BITSIZE (GET_MODE (x
)) + 1);
7742 /* If the constant is negative, take its 1's complement and remask.
7743 Then see how many zero bits we have. */
7744 nonzero
= INTVAL (x
) & GET_MODE_MASK (mode
);
7745 if (bitwidth
<= HOST_BITS_PER_WIDE_INT
7746 && (nonzero
& ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))) != 0)
7747 nonzero
= (~ nonzero
) & GET_MODE_MASK (mode
);
7749 return (nonzero
== 0 ? bitwidth
: bitwidth
- floor_log2 (nonzero
) - 1);
7752 /* If this is a SUBREG for a promoted object that is sign-extended
7753 and we are looking at it in a wider mode, we know that at least the
7754 high-order bits are known to be sign bit copies. */
7756 if (SUBREG_PROMOTED_VAR_P (x
) && ! SUBREG_PROMOTED_UNSIGNED_P (x
))
7757 return MAX (bitwidth
- GET_MODE_BITSIZE (GET_MODE (x
)) + 1,
7758 num_sign_bit_copies (SUBREG_REG (x
), mode
));
7760 /* For a smaller object, just ignore the high bits. */
7761 if (bitwidth
<= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x
))))
7763 num0
= num_sign_bit_copies (SUBREG_REG (x
), VOIDmode
);
7764 return MAX (1, (num0
7765 - (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x
)))
7769 #ifdef WORD_REGISTER_OPERATIONS
7770 #ifdef LOAD_EXTEND_OP
7771 /* For paradoxical SUBREGs on machines where all register operations
7772 affect the entire register, just look inside. Note that we are
7773 passing MODE to the recursive call, so the number of sign bit copies
7774 will remain relative to that mode, not the inner mode. */
7776 /* This works only if loads sign extend. Otherwise, if we get a
7777 reload for the inner part, it may be loaded from the stack, and
7778 then we lose all sign bit copies that existed before the store
7781 if ((GET_MODE_SIZE (GET_MODE (x
))
7782 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
7783 && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x
))) == SIGN_EXTEND
)
7784 return num_sign_bit_copies (SUBREG_REG (x
), mode
);
7790 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
)
7791 return MAX (1, bitwidth
- INTVAL (XEXP (x
, 1)));
7795 return (bitwidth
- GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
7796 + num_sign_bit_copies (XEXP (x
, 0), VOIDmode
));
7799 /* For a smaller object, just ignore the high bits. */
7800 num0
= num_sign_bit_copies (XEXP (x
, 0), VOIDmode
);
7801 return MAX (1, (num0
- (GET_MODE_BITSIZE (GET_MODE (XEXP (x
, 0)))
7805 return num_sign_bit_copies (XEXP (x
, 0), mode
);
7807 case ROTATE
: case ROTATERT
:
7808 /* If we are rotating left by a number of bits less than the number
7809 of sign bit copies, we can just subtract that amount from the
7811 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
7812 && INTVAL (XEXP (x
, 1)) >= 0 && INTVAL (XEXP (x
, 1)) < bitwidth
)
7814 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7815 return MAX (1, num0
- (code
== ROTATE
? INTVAL (XEXP (x
, 1))
7816 : bitwidth
- INTVAL (XEXP (x
, 1))));
7821 /* In general, this subtracts one sign bit copy. But if the value
7822 is known to be positive, the number of sign bit copies is the
7823 same as that of the input. Finally, if the input has just one bit
7824 that might be nonzero, all the bits are copies of the sign bit. */
7825 nonzero
= nonzero_bits (XEXP (x
, 0), mode
);
7829 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7831 && bitwidth
<= HOST_BITS_PER_WIDE_INT
7832 && (((HOST_WIDE_INT
) 1 << (bitwidth
- 1)) & nonzero
))
7837 case IOR
: case AND
: case XOR
:
7838 case SMIN
: case SMAX
: case UMIN
: case UMAX
:
7839 /* Logical operations will preserve the number of sign-bit copies.
7840 MIN and MAX operations always return one of the operands. */
7841 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7842 num1
= num_sign_bit_copies (XEXP (x
, 1), mode
);
7843 return MIN (num0
, num1
);
7845 case PLUS
: case MINUS
:
7846 /* For addition and subtraction, we can have a 1-bit carry. However,
7847 if we are subtracting 1 from a positive number, there will not
7848 be such a carry. Furthermore, if the positive number is known to
7849 be 0 or 1, we know the result is either -1 or 0. */
7851 if (code
== PLUS
&& XEXP (x
, 1) == constm1_rtx
7852 && bitwidth
<= HOST_BITS_PER_WIDE_INT
)
7854 nonzero
= nonzero_bits (XEXP (x
, 0), mode
);
7855 if ((((HOST_WIDE_INT
) 1 << (bitwidth
- 1)) & nonzero
) == 0)
7856 return (nonzero
== 1 || nonzero
== 0 ? bitwidth
7857 : bitwidth
- floor_log2 (nonzero
) - 1);
7860 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7861 num1
= num_sign_bit_copies (XEXP (x
, 1), mode
);
7862 return MAX (1, MIN (num0
, num1
) - 1);
7865 /* The number of bits of the product is the sum of the number of
7866 bits of both terms. However, unless one of the terms if known
7867 to be positive, we must allow for an additional bit since negating
7868 a negative number can remove one sign bit copy. */
7870 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7871 num1
= num_sign_bit_copies (XEXP (x
, 1), mode
);
7873 result
= bitwidth
- (bitwidth
- num0
) - (bitwidth
- num1
);
7875 && bitwidth
<= HOST_BITS_PER_WIDE_INT
7876 && ((nonzero_bits (XEXP (x
, 0), mode
)
7877 & ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))) != 0)
7878 && ((nonzero_bits (XEXP (x
, 1), mode
)
7879 & ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))) != 0))
7882 return MAX (1, result
);
7885 /* The result must be <= the first operand. */
7886 return num_sign_bit_copies (XEXP (x
, 0), mode
);
7889 /* The result must be <= the scond operand. */
7890 return num_sign_bit_copies (XEXP (x
, 1), mode
);
7893 /* Similar to unsigned division, except that we have to worry about
7894 the case where the divisor is negative, in which case we have
7896 result
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7898 && bitwidth
<= HOST_BITS_PER_WIDE_INT
7899 && (nonzero_bits (XEXP (x
, 1), mode
)
7900 & ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))) != 0)
7906 result
= num_sign_bit_copies (XEXP (x
, 1), mode
);
7908 && bitwidth
<= HOST_BITS_PER_WIDE_INT
7909 && (nonzero_bits (XEXP (x
, 1), mode
)
7910 & ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))) != 0)
7916 /* Shifts by a constant add to the number of bits equal to the
7918 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7919 if (GET_CODE (XEXP (x
, 1)) == CONST_INT
7920 && INTVAL (XEXP (x
, 1)) > 0)
7921 num0
= MIN (bitwidth
, num0
+ INTVAL (XEXP (x
, 1)));
7926 /* Left shifts destroy copies. */
7927 if (GET_CODE (XEXP (x
, 1)) != CONST_INT
7928 || INTVAL (XEXP (x
, 1)) < 0
7929 || INTVAL (XEXP (x
, 1)) >= bitwidth
)
7932 num0
= num_sign_bit_copies (XEXP (x
, 0), mode
);
7933 return MAX (1, num0
- INTVAL (XEXP (x
, 1)));
7936 num0
= num_sign_bit_copies (XEXP (x
, 1), mode
);
7937 num1
= num_sign_bit_copies (XEXP (x
, 2), mode
);
7938 return MIN (num0
, num1
);
7940 case EQ
: case NE
: case GE
: case GT
: case LE
: case LT
:
7941 case GEU
: case GTU
: case LEU
: case LTU
:
7942 if (STORE_FLAG_VALUE
== -1)
7950 /* If we haven't been able to figure it out by one of the above rules,
7951 see if some of the high-order bits are known to be zero. If so,
7952 count those bits and return one less than that amount. If we can't
7953 safely compute the mask for this mode, always return BITWIDTH. */
7955 if (bitwidth
> HOST_BITS_PER_WIDE_INT
)
7958 nonzero
= nonzero_bits (x
, mode
);
7959 return (nonzero
& ((HOST_WIDE_INT
) 1 << (bitwidth
- 1))
7960 ? 1 : bitwidth
- floor_log2 (nonzero
) - 1);
7963 /* Return the number of "extended" bits there are in X, when interpreted
7964 as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For
7965 unsigned quantities, this is the number of high-order zero bits.
7966 For signed quantities, this is the number of copies of the sign bit
7967 minus 1. In both case, this function returns the number of "spare"
7968 bits. For example, if two quantities for which this function returns
7969 at least 1 are added, the addition is known not to overflow.
7971 This function will always return 0 unless called during combine, which
7972 implies that it must be called from a define_split. */
7975 extended_count (x
, mode
, unsignedp
)
7977 enum machine_mode mode
;
7980 if (nonzero_sign_valid
== 0)
7984 ? (GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
7985 && (GET_MODE_BITSIZE (mode
) - 1
7986 - floor_log2 (nonzero_bits (x
, mode
))))
7987 : num_sign_bit_copies (x
, mode
) - 1);
7990 /* This function is called from `simplify_shift_const' to merge two
7991 outer operations. Specifically, we have already found that we need
7992 to perform operation *POP0 with constant *PCONST0 at the outermost
7993 position. We would now like to also perform OP1 with constant CONST1
7994 (with *POP0 being done last).
7996 Return 1 if we can do the operation and update *POP0 and *PCONST0 with
7997 the resulting operation. *PCOMP_P is set to 1 if we would need to
7998 complement the innermost operand, otherwise it is unchanged.
8000 MODE is the mode in which the operation will be done. No bits outside
8001 the width of this mode matter. It is assumed that the width of this mode
8002 is smaller than or equal to HOST_BITS_PER_WIDE_INT.
8004 If *POP0 or OP1 are NIL, it means no operation is required. Only NEG, PLUS,
8005 IOR, XOR, and AND are supported. We may set *POP0 to SET if the proper
8006 result is simply *PCONST0.
8008 If the resulting operation cannot be expressed as one operation, we
8009 return 0 and do not change *POP0, *PCONST0, and *PCOMP_P. */
8012 merge_outer_ops (pop0
, pconst0
, op1
, const1
, mode
, pcomp_p
)
8013 enum rtx_code
*pop0
;
8014 HOST_WIDE_INT
*pconst0
;
8016 HOST_WIDE_INT const1
;
8017 enum machine_mode mode
;
8020 enum rtx_code op0
= *pop0
;
8021 HOST_WIDE_INT const0
= *pconst0
;
8022 int width
= GET_MODE_BITSIZE (mode
);
8024 const0
&= GET_MODE_MASK (mode
);
8025 const1
&= GET_MODE_MASK (mode
);
8027 /* If OP0 is an AND, clear unimportant bits in CONST1. */
8031 /* If OP0 or OP1 is NIL, this is easy. Similarly if they are the same or
8034 if (op1
== NIL
|| op0
== SET
)
8037 else if (op0
== NIL
)
8038 op0
= op1
, const0
= const1
;
8040 else if (op0
== op1
)
8064 /* Otherwise, if either is a PLUS or NEG, we can't do anything. */
8065 else if (op0
== PLUS
|| op1
== PLUS
|| op0
== NEG
|| op1
== NEG
)
8068 /* If the two constants aren't the same, we can't do anything. The
8069 remaining six cases can all be done. */
8070 else if (const0
!= const1
)
8078 /* (a & b) | b == b */
8080 else /* op1 == XOR */
8081 /* (a ^ b) | b == a | b */
8087 /* (a & b) ^ b == (~a) & b */
8088 op0
= AND
, *pcomp_p
= 1;
8089 else /* op1 == IOR */
8090 /* (a | b) ^ b == a & ~b */
8091 op0
= AND
, *pconst0
= ~ const0
;
8096 /* (a | b) & b == b */
8098 else /* op1 == XOR */
8099 /* (a ^ b) & b) == (~a) & b */
8106 /* Check for NO-OP cases. */
8107 const0
&= GET_MODE_MASK (mode
);
8109 && (op0
== IOR
|| op0
== XOR
|| op0
== PLUS
))
8111 else if (const0
== 0 && op0
== AND
)
8113 else if (const0
== GET_MODE_MASK (mode
) && op0
== AND
)
8116 /* If this would be an entire word for the target, but is not for
8117 the host, then sign-extend on the host so that the number will look
8118 the same way on the host that it would on the target.
8120 For example, when building a 64 bit alpha hosted 32 bit sparc
8121 targeted compiler, then we want the 32 bit unsigned value -1 to be
8122 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
8123 The later confuses the sparc backend. */
8125 if (BITS_PER_WORD
< HOST_BITS_PER_WIDE_INT
&& BITS_PER_WORD
== width
8126 && (const0
& ((HOST_WIDE_INT
) 1 << (width
- 1))))
8127 const0
|= ((HOST_WIDE_INT
) (-1) << width
);
8135 /* Simplify a shift of VAROP by COUNT bits. CODE says what kind of shift.
8136 The result of the shift is RESULT_MODE. X, if non-zero, is an expression
8137 that we started with.
8139 The shift is normally computed in the widest mode we find in VAROP, as
8140 long as it isn't a different number of words than RESULT_MODE. Exceptions
8141 are ASHIFTRT and ROTATE, which are always done in their original mode, */
8144 simplify_shift_const (x
, code
, result_mode
, varop
, count
)
8147 enum machine_mode result_mode
;
8151 enum rtx_code orig_code
= code
;
8152 int orig_count
= count
;
8153 enum machine_mode mode
= result_mode
;
8154 enum machine_mode shift_mode
, tmode
;
8156 = (GET_MODE_SIZE (mode
) + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
;
8157 /* We form (outer_op (code varop count) (outer_const)). */
8158 enum rtx_code outer_op
= NIL
;
8159 HOST_WIDE_INT outer_const
= 0;
8161 int complement_p
= 0;
8164 /* If we were given an invalid count, don't do anything except exactly
8165 what was requested. */
8167 if (count
< 0 || count
> GET_MODE_BITSIZE (mode
))
8172 return gen_rtx (code
, mode
, varop
, GEN_INT (count
));
8175 /* Unless one of the branches of the `if' in this loop does a `continue',
8176 we will `break' the loop after the `if'. */
8180 /* If we have an operand of (clobber (const_int 0)), just return that
8182 if (GET_CODE (varop
) == CLOBBER
)
8185 /* If we discovered we had to complement VAROP, leave. Making a NOT
8186 here would cause an infinite loop. */
8190 /* Convert ROTATERT to ROTATE. */
8191 if (code
== ROTATERT
)
8192 code
= ROTATE
, count
= GET_MODE_BITSIZE (result_mode
) - count
;
8194 /* We need to determine what mode we will do the shift in. If the
8195 shift is a right shift or a ROTATE, we must always do it in the mode
8196 it was originally done in. Otherwise, we can do it in MODE, the
8197 widest mode encountered. */
8199 = (code
== ASHIFTRT
|| code
== LSHIFTRT
|| code
== ROTATE
8200 ? result_mode
: mode
);
8202 /* Handle cases where the count is greater than the size of the mode
8203 minus 1. For ASHIFT, use the size minus one as the count (this can
8204 occur when simplifying (lshiftrt (ashiftrt ..))). For rotates,
8205 take the count modulo the size. For other shifts, the result is
8208 Since these shifts are being produced by the compiler by combining
8209 multiple operations, each of which are defined, we know what the
8210 result is supposed to be. */
8212 if (count
> GET_MODE_BITSIZE (shift_mode
) - 1)
8214 if (code
== ASHIFTRT
)
8215 count
= GET_MODE_BITSIZE (shift_mode
) - 1;
8216 else if (code
== ROTATE
|| code
== ROTATERT
)
8217 count
%= GET_MODE_BITSIZE (shift_mode
);
8220 /* We can't simply return zero because there may be an
8228 /* Negative counts are invalid and should not have been made (a
8229 programmer-specified negative count should have been handled
8234 /* An arithmetic right shift of a quantity known to be -1 or 0
8236 if (code
== ASHIFTRT
8237 && (num_sign_bit_copies (varop
, shift_mode
)
8238 == GET_MODE_BITSIZE (shift_mode
)))
8244 /* If we are doing an arithmetic right shift and discarding all but
8245 the sign bit copies, this is equivalent to doing a shift by the
8246 bitsize minus one. Convert it into that shift because it will often
8247 allow other simplifications. */
8249 if (code
== ASHIFTRT
8250 && (count
+ num_sign_bit_copies (varop
, shift_mode
)
8251 >= GET_MODE_BITSIZE (shift_mode
)))
8252 count
= GET_MODE_BITSIZE (shift_mode
) - 1;
8254 /* We simplify the tests below and elsewhere by converting
8255 ASHIFTRT to LSHIFTRT if we know the sign bit is clear.
8256 `make_compound_operation' will convert it to a ASHIFTRT for
8257 those machines (such as Vax) that don't have a LSHIFTRT. */
8258 if (GET_MODE_BITSIZE (shift_mode
) <= HOST_BITS_PER_WIDE_INT
8260 && ((nonzero_bits (varop
, shift_mode
)
8261 & ((HOST_WIDE_INT
) 1 << (GET_MODE_BITSIZE (shift_mode
) - 1)))
8265 switch (GET_CODE (varop
))
8271 new = expand_compound_operation (varop
);
8280 /* If we have (xshiftrt (mem ...) C) and C is MODE_WIDTH
8281 minus the width of a smaller mode, we can do this with a
8282 SIGN_EXTEND or ZERO_EXTEND from the narrower memory location. */
8283 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
8284 && ! mode_dependent_address_p (XEXP (varop
, 0))
8285 && ! MEM_VOLATILE_P (varop
)
8286 && (tmode
= mode_for_size (GET_MODE_BITSIZE (mode
) - count
,
8287 MODE_INT
, 1)) != BLKmode
)
8289 if (BYTES_BIG_ENDIAN
)
8290 new = gen_rtx (MEM
, tmode
, XEXP (varop
, 0));
8292 new = gen_rtx (MEM
, tmode
,
8293 plus_constant (XEXP (varop
, 0),
8294 count
/ BITS_PER_UNIT
));
8295 RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (varop
);
8296 MEM_VOLATILE_P (new) = MEM_VOLATILE_P (varop
);
8297 MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (varop
);
8298 varop
= gen_rtx_combine (code
== ASHIFTRT
? SIGN_EXTEND
8299 : ZERO_EXTEND
, mode
, new);
8306 /* Similar to the case above, except that we can only do this if
8307 the resulting mode is the same as that of the underlying
8308 MEM and adjust the address depending on the *bits* endianness
8309 because of the way that bit-field extract insns are defined. */
8310 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
8311 && (tmode
= mode_for_size (GET_MODE_BITSIZE (mode
) - count
,
8312 MODE_INT
, 1)) != BLKmode
8313 && tmode
== GET_MODE (XEXP (varop
, 0)))
8315 if (BITS_BIG_ENDIAN
)
8316 new = XEXP (varop
, 0);
8319 new = copy_rtx (XEXP (varop
, 0));
8320 SUBST (XEXP (new, 0),
8321 plus_constant (XEXP (new, 0),
8322 count
/ BITS_PER_UNIT
));
8325 varop
= gen_rtx_combine (code
== ASHIFTRT
? SIGN_EXTEND
8326 : ZERO_EXTEND
, mode
, new);
8333 /* If VAROP is a SUBREG, strip it as long as the inner operand has
8334 the same number of words as what we've seen so far. Then store
8335 the widest mode in MODE. */
8336 if (subreg_lowpart_p (varop
)
8337 && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
8338 > GET_MODE_SIZE (GET_MODE (varop
)))
8339 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop
)))
8340 + (UNITS_PER_WORD
- 1)) / UNITS_PER_WORD
)
8343 varop
= SUBREG_REG (varop
);
8344 if (GET_MODE_SIZE (GET_MODE (varop
)) > GET_MODE_SIZE (mode
))
8345 mode
= GET_MODE (varop
);
8351 /* Some machines use MULT instead of ASHIFT because MULT
8352 is cheaper. But it is still better on those machines to
8353 merge two shifts into one. */
8354 if (GET_CODE (XEXP (varop
, 1)) == CONST_INT
8355 && exact_log2 (INTVAL (XEXP (varop
, 1))) >= 0)
8357 varop
= gen_binary (ASHIFT
, GET_MODE (varop
), XEXP (varop
, 0),
8358 GEN_INT (exact_log2 (INTVAL (XEXP (varop
, 1)))));;
8364 /* Similar, for when divides are cheaper. */
8365 if (GET_CODE (XEXP (varop
, 1)) == CONST_INT
8366 && exact_log2 (INTVAL (XEXP (varop
, 1))) >= 0)
8368 varop
= gen_binary (LSHIFTRT
, GET_MODE (varop
), XEXP (varop
, 0),
8369 GEN_INT (exact_log2 (INTVAL (XEXP (varop
, 1)))));
8375 /* If we are extracting just the sign bit of an arithmetic right
8376 shift, that shift is not needed. */
8377 if (code
== LSHIFTRT
&& count
== GET_MODE_BITSIZE (result_mode
) - 1)
8379 varop
= XEXP (varop
, 0);
8383 /* ... fall through ... */
8388 /* Here we have two nested shifts. The result is usually the
8389 AND of a new shift with a mask. We compute the result below. */
8390 if (GET_CODE (XEXP (varop
, 1)) == CONST_INT
8391 && INTVAL (XEXP (varop
, 1)) >= 0
8392 && INTVAL (XEXP (varop
, 1)) < GET_MODE_BITSIZE (GET_MODE (varop
))
8393 && GET_MODE_BITSIZE (result_mode
) <= HOST_BITS_PER_WIDE_INT
8394 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
)
8396 enum rtx_code first_code
= GET_CODE (varop
);
8397 int first_count
= INTVAL (XEXP (varop
, 1));
8398 unsigned HOST_WIDE_INT mask
;
8401 /* We have one common special case. We can't do any merging if
8402 the inner code is an ASHIFTRT of a smaller mode. However, if
8403 we have (ashift:M1 (subreg:M1 (ashiftrt:M2 FOO C1) 0) C2)
8404 with C2 == GET_MODE_BITSIZE (M1) - GET_MODE_BITSIZE (M2),
8405 we can convert it to
8406 (ashiftrt:M1 (ashift:M1 (and:M1 (subreg:M1 FOO 0 C2) C3) C1).
8407 This simplifies certain SIGN_EXTEND operations. */
8408 if (code
== ASHIFT
&& first_code
== ASHIFTRT
8409 && (GET_MODE_BITSIZE (result_mode
)
8410 - GET_MODE_BITSIZE (GET_MODE (varop
))) == count
)
8412 /* C3 has the low-order C1 bits zero. */
8414 mask
= (GET_MODE_MASK (mode
)
8415 & ~ (((HOST_WIDE_INT
) 1 << first_count
) - 1));
8417 varop
= simplify_and_const_int (NULL_RTX
, result_mode
,
8418 XEXP (varop
, 0), mask
);
8419 varop
= simplify_shift_const (NULL_RTX
, ASHIFT
, result_mode
,
8421 count
= first_count
;
8426 /* If this was (ashiftrt (ashift foo C1) C2) and FOO has more
8427 than C1 high-order bits equal to the sign bit, we can convert
8428 this to either an ASHIFT or a ASHIFTRT depending on the
8431 We cannot do this if VAROP's mode is not SHIFT_MODE. */
8433 if (code
== ASHIFTRT
&& first_code
== ASHIFT
8434 && GET_MODE (varop
) == shift_mode
8435 && (num_sign_bit_copies (XEXP (varop
, 0), shift_mode
)
8438 count
-= first_count
;
8440 count
= - count
, code
= ASHIFT
;
8441 varop
= XEXP (varop
, 0);
8445 /* There are some cases we can't do. If CODE is ASHIFTRT,
8446 we can only do this if FIRST_CODE is also ASHIFTRT.
8448 We can't do the case when CODE is ROTATE and FIRST_CODE is
8451 If the mode of this shift is not the mode of the outer shift,
8452 we can't do this if either shift is a right shift or ROTATE.
8454 Finally, we can't do any of these if the mode is too wide
8455 unless the codes are the same.
8457 Handle the case where the shift codes are the same
8460 if (code
== first_code
)
8462 if (GET_MODE (varop
) != result_mode
8463 && (code
== ASHIFTRT
|| code
== LSHIFTRT
8467 count
+= first_count
;
8468 varop
= XEXP (varop
, 0);
8472 if (code
== ASHIFTRT
8473 || (code
== ROTATE
&& first_code
== ASHIFTRT
)
8474 || GET_MODE_BITSIZE (mode
) > HOST_BITS_PER_WIDE_INT
8475 || (GET_MODE (varop
) != result_mode
8476 && (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
8477 || first_code
== ROTATE
8478 || code
== ROTATE
)))
8481 /* To compute the mask to apply after the shift, shift the
8482 nonzero bits of the inner shift the same way the
8483 outer shift will. */
8485 mask_rtx
= GEN_INT (nonzero_bits (varop
, GET_MODE (varop
)));
8488 = simplify_binary_operation (code
, result_mode
, mask_rtx
,
8491 /* Give up if we can't compute an outer operation to use. */
8493 || GET_CODE (mask_rtx
) != CONST_INT
8494 || ! merge_outer_ops (&outer_op
, &outer_const
, AND
,
8496 result_mode
, &complement_p
))
8499 /* If the shifts are in the same direction, we add the
8500 counts. Otherwise, we subtract them. */
8501 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
8502 == (first_code
== ASHIFTRT
|| first_code
== LSHIFTRT
))
8503 count
+= first_count
;
8505 count
-= first_count
;
8507 /* If COUNT is positive, the new shift is usually CODE,
8508 except for the two exceptions below, in which case it is
8509 FIRST_CODE. If the count is negative, FIRST_CODE should
8512 && ((first_code
== ROTATE
&& code
== ASHIFT
)
8513 || (first_code
== ASHIFTRT
&& code
== LSHIFTRT
)))
8516 code
= first_code
, count
= - count
;
8518 varop
= XEXP (varop
, 0);
8522 /* If we have (A << B << C) for any shift, we can convert this to
8523 (A << C << B). This wins if A is a constant. Only try this if
8524 B is not a constant. */
8526 else if (GET_CODE (varop
) == code
8527 && GET_CODE (XEXP (varop
, 1)) != CONST_INT
8529 = simplify_binary_operation (code
, mode
,
8533 varop
= gen_rtx_combine (code
, mode
, new, XEXP (varop
, 1));
8540 /* Make this fit the case below. */
8541 varop
= gen_rtx_combine (XOR
, mode
, XEXP (varop
, 0),
8542 GEN_INT (GET_MODE_MASK (mode
)));
8548 /* If we have (xshiftrt (ior (plus X (const_int -1)) X) C)
8549 with C the size of VAROP - 1 and the shift is logical if
8550 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
8551 we have an (le X 0) operation. If we have an arithmetic shift
8552 and STORE_FLAG_VALUE is 1 or we have a logical shift with
8553 STORE_FLAG_VALUE of -1, we have a (neg (le X 0)) operation. */
8555 if (GET_CODE (varop
) == IOR
&& GET_CODE (XEXP (varop
, 0)) == PLUS
8556 && XEXP (XEXP (varop
, 0), 1) == constm1_rtx
8557 && (STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
8558 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
8559 && count
== GET_MODE_BITSIZE (GET_MODE (varop
)) - 1
8560 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
8563 varop
= gen_rtx_combine (LE
, GET_MODE (varop
), XEXP (varop
, 1),
8566 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
8567 varop
= gen_rtx_combine (NEG
, GET_MODE (varop
), varop
);
8572 /* If we have (shift (logical)), move the logical to the outside
8573 to allow it to possibly combine with another logical and the
8574 shift to combine with another shift. This also canonicalizes to
8575 what a ZERO_EXTRACT looks like. Also, some machines have
8576 (and (shift)) insns. */
8578 if (GET_CODE (XEXP (varop
, 1)) == CONST_INT
8579 && (new = simplify_binary_operation (code
, result_mode
,
8581 GEN_INT (count
))) != 0
8582 && GET_CODE(new) == CONST_INT
8583 && merge_outer_ops (&outer_op
, &outer_const
, GET_CODE (varop
),
8584 INTVAL (new), result_mode
, &complement_p
))
8586 varop
= XEXP (varop
, 0);
8590 /* If we can't do that, try to simplify the shift in each arm of the
8591 logical expression, make a new logical expression, and apply
8592 the inverse distributive law. */
8594 rtx lhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
8595 XEXP (varop
, 0), count
);
8596 rtx rhs
= simplify_shift_const (NULL_RTX
, code
, shift_mode
,
8597 XEXP (varop
, 1), count
);
8599 varop
= gen_binary (GET_CODE (varop
), shift_mode
, lhs
, rhs
);
8600 varop
= apply_distributive_law (varop
);
8607 /* convert (lshiftrt (eq FOO 0) C) to (xor FOO 1) if STORE_FLAG_VALUE
8608 says that the sign bit can be tested, FOO has mode MODE, C is
8609 GET_MODE_BITSIZE (MODE) - 1, and FOO has only its low-order bit
8610 that may be nonzero. */
8611 if (code
== LSHIFTRT
8612 && XEXP (varop
, 1) == const0_rtx
8613 && GET_MODE (XEXP (varop
, 0)) == result_mode
8614 && count
== GET_MODE_BITSIZE (result_mode
) - 1
8615 && GET_MODE_BITSIZE (result_mode
) <= HOST_BITS_PER_WIDE_INT
8616 && ((STORE_FLAG_VALUE
8617 & ((HOST_WIDE_INT
) 1 << (GET_MODE_BITSIZE (result_mode
) - 1))))
8618 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
8619 && merge_outer_ops (&outer_op
, &outer_const
, XOR
,
8620 (HOST_WIDE_INT
) 1, result_mode
,
8623 varop
= XEXP (varop
, 0);
8630 /* (lshiftrt (neg A) C) where A is either 0 or 1 and C is one less
8631 than the number of bits in the mode is equivalent to A. */
8632 if (code
== LSHIFTRT
&& count
== GET_MODE_BITSIZE (result_mode
) - 1
8633 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1)
8635 varop
= XEXP (varop
, 0);
8640 /* NEG commutes with ASHIFT since it is multiplication. Move the
8641 NEG outside to allow shifts to combine. */
8643 && merge_outer_ops (&outer_op
, &outer_const
, NEG
,
8644 (HOST_WIDE_INT
) 0, result_mode
,
8647 varop
= XEXP (varop
, 0);
8653 /* (lshiftrt (plus A -1) C) where A is either 0 or 1 and C
8654 is one less than the number of bits in the mode is
8655 equivalent to (xor A 1). */
8656 if (code
== LSHIFTRT
&& count
== GET_MODE_BITSIZE (result_mode
) - 1
8657 && XEXP (varop
, 1) == constm1_rtx
8658 && nonzero_bits (XEXP (varop
, 0), result_mode
) == 1
8659 && merge_outer_ops (&outer_op
, &outer_const
, XOR
,
8660 (HOST_WIDE_INT
) 1, result_mode
,
8664 varop
= XEXP (varop
, 0);
8668 /* If we have (xshiftrt (plus FOO BAR) C), and the only bits
8669 that might be nonzero in BAR are those being shifted out and those
8670 bits are known zero in FOO, we can replace the PLUS with FOO.
8671 Similarly in the other operand order. This code occurs when
8672 we are computing the size of a variable-size array. */
8674 if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
8675 && count
< HOST_BITS_PER_WIDE_INT
8676 && nonzero_bits (XEXP (varop
, 1), result_mode
) >> count
== 0
8677 && (nonzero_bits (XEXP (varop
, 1), result_mode
)
8678 & nonzero_bits (XEXP (varop
, 0), result_mode
)) == 0)
8680 varop
= XEXP (varop
, 0);
8683 else if ((code
== ASHIFTRT
|| code
== LSHIFTRT
)
8684 && count
< HOST_BITS_PER_WIDE_INT
8685 && GET_MODE_BITSIZE (result_mode
) <= HOST_BITS_PER_WIDE_INT
8686 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
8688 && 0 == (nonzero_bits (XEXP (varop
, 0), result_mode
)
8689 & nonzero_bits (XEXP (varop
, 1),
8692 varop
= XEXP (varop
, 1);
8696 /* (ashift (plus foo C) N) is (plus (ashift foo N) C'). */
8698 && GET_CODE (XEXP (varop
, 1)) == CONST_INT
8699 && (new = simplify_binary_operation (ASHIFT
, result_mode
,
8701 GEN_INT (count
))) != 0
8702 && GET_CODE(new) == CONST_INT
8703 && merge_outer_ops (&outer_op
, &outer_const
, PLUS
,
8704 INTVAL (new), result_mode
, &complement_p
))
8706 varop
= XEXP (varop
, 0);
8712 /* If we have (xshiftrt (minus (ashiftrt X C)) X) C)
8713 with C the size of VAROP - 1 and the shift is logical if
8714 STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1,
8715 we have a (gt X 0) operation. If the shift is arithmetic with
8716 STORE_FLAG_VALUE of 1 or logical with STORE_FLAG_VALUE == -1,
8717 we have a (neg (gt X 0)) operation. */
8719 if ((STORE_FLAG_VALUE
== 1 || STORE_FLAG_VALUE
== -1)
8720 && GET_CODE (XEXP (varop
, 0)) == ASHIFTRT
8721 && count
== GET_MODE_BITSIZE (GET_MODE (varop
)) - 1
8722 && (code
== LSHIFTRT
|| code
== ASHIFTRT
)
8723 && GET_CODE (XEXP (XEXP (varop
, 0), 1)) == CONST_INT
8724 && INTVAL (XEXP (XEXP (varop
, 0), 1)) == count
8725 && rtx_equal_p (XEXP (XEXP (varop
, 0), 0), XEXP (varop
, 1)))
8728 varop
= gen_rtx_combine (GT
, GET_MODE (varop
), XEXP (varop
, 1),
8731 if (STORE_FLAG_VALUE
== 1 ? code
== ASHIFTRT
: code
== LSHIFTRT
)
8732 varop
= gen_rtx_combine (NEG
, GET_MODE (varop
), varop
);
8745 /* We need to determine what mode to do the shift in. If the shift is
8746 a right shift or ROTATE, we must always do it in the mode it was
8747 originally done in. Otherwise, we can do it in MODE, the widest mode
8748 encountered. The code we care about is that of the shift that will
8749 actually be done, not the shift that was originally requested. */
8751 = (code
== ASHIFTRT
|| code
== LSHIFTRT
|| code
== ROTATE
8752 ? result_mode
: mode
);
8754 /* We have now finished analyzing the shift. The result should be
8755 a shift of type CODE with SHIFT_MODE shifting VAROP COUNT places. If
8756 OUTER_OP is non-NIL, it is an operation that needs to be applied
8757 to the result of the shift. OUTER_CONST is the relevant constant,
8758 but we must turn off all bits turned off in the shift.
8760 If we were passed a value for X, see if we can use any pieces of
8761 it. If not, make new rtx. */
8763 if (x
&& GET_RTX_CLASS (GET_CODE (x
)) == '2'
8764 && GET_CODE (XEXP (x
, 1)) == CONST_INT
8765 && INTVAL (XEXP (x
, 1)) == count
)
8766 const_rtx
= XEXP (x
, 1);
8768 const_rtx
= GEN_INT (count
);
8770 if (x
&& GET_CODE (XEXP (x
, 0)) == SUBREG
8771 && GET_MODE (XEXP (x
, 0)) == shift_mode
8772 && SUBREG_REG (XEXP (x
, 0)) == varop
)
8773 varop
= XEXP (x
, 0);
8774 else if (GET_MODE (varop
) != shift_mode
)
8775 varop
= gen_lowpart_for_combine (shift_mode
, varop
);
8777 /* If we can't make the SUBREG, try to return what we were given. */
8778 if (GET_CODE (varop
) == CLOBBER
)
8779 return x
? x
: varop
;
8781 new = simplify_binary_operation (code
, shift_mode
, varop
, const_rtx
);
8786 if (x
== 0 || GET_CODE (x
) != code
|| GET_MODE (x
) != shift_mode
)
8787 x
= gen_rtx_combine (code
, shift_mode
, varop
, const_rtx
);
8789 SUBST (XEXP (x
, 0), varop
);
8790 SUBST (XEXP (x
, 1), const_rtx
);
8793 /* If we have an outer operation and we just made a shift, it is
8794 possible that we could have simplified the shift were it not
8795 for the outer operation. So try to do the simplification
8798 if (outer_op
!= NIL
&& GET_CODE (x
) == code
8799 && GET_CODE (XEXP (x
, 1)) == CONST_INT
)
8800 x
= simplify_shift_const (x
, code
, shift_mode
, XEXP (x
, 0),
8801 INTVAL (XEXP (x
, 1)));
8803 /* If we were doing a LSHIFTRT in a wider mode than it was originally,
8804 turn off all the bits that the shift would have turned off. */
8805 if (orig_code
== LSHIFTRT
&& result_mode
!= shift_mode
)
8806 x
= simplify_and_const_int (NULL_RTX
, shift_mode
, x
,
8807 GET_MODE_MASK (result_mode
) >> orig_count
);
8809 /* Do the remainder of the processing in RESULT_MODE. */
8810 x
= gen_lowpart_for_combine (result_mode
, x
);
8812 /* If COMPLEMENT_P is set, we have to complement X before doing the outer
8815 x
= gen_unary (NOT
, result_mode
, result_mode
, x
);
8817 if (outer_op
!= NIL
)
8819 if (GET_MODE_BITSIZE (result_mode
) < HOST_BITS_PER_WIDE_INT
)
8821 int width
= GET_MODE_BITSIZE (result_mode
);
8823 outer_const
&= GET_MODE_MASK (result_mode
);
8825 /* If this would be an entire word for the target, but is not for
8826 the host, then sign-extend on the host so that the number will
8827 look the same way on the host that it would on the target.
8829 For example, when building a 64 bit alpha hosted 32 bit sparc
8830 targeted compiler, then we want the 32 bit unsigned value -1 to be
8831 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
8832 The later confuses the sparc backend. */
8834 if (BITS_PER_WORD
< HOST_BITS_PER_WIDE_INT
&& BITS_PER_WORD
== width
8835 && (outer_const
& ((HOST_WIDE_INT
) 1 << (width
- 1))))
8836 outer_const
|= ((HOST_WIDE_INT
) (-1) << width
);
8839 if (outer_op
== AND
)
8840 x
= simplify_and_const_int (NULL_RTX
, result_mode
, x
, outer_const
);
8841 else if (outer_op
== SET
)
8842 /* This means that we have determined that the result is
8843 equivalent to a constant. This should be rare. */
8844 x
= GEN_INT (outer_const
);
8845 else if (GET_RTX_CLASS (outer_op
) == '1')
8846 x
= gen_unary (outer_op
, result_mode
, result_mode
, x
);
8848 x
= gen_binary (outer_op
, result_mode
, x
, GEN_INT (outer_const
));
8854 /* Like recog, but we receive the address of a pointer to a new pattern.
8855 We try to match the rtx that the pointer points to.
8856 If that fails, we may try to modify or replace the pattern,
8857 storing the replacement into the same pointer object.
8859 Modifications include deletion or addition of CLOBBERs.
8861 PNOTES is a pointer to a location where any REG_UNUSED notes added for
8862 the CLOBBERs are placed.
8864 PADDED_SCRATCHES is set to the number of (clobber (scratch)) patterns
8867 The value is the final insn code from the pattern ultimately matched,
8871 recog_for_combine (pnewpat
, insn
, pnotes
, padded_scratches
)
8875 int *padded_scratches
;
8877 register rtx pat
= *pnewpat
;
8878 int insn_code_number
;
8879 int num_clobbers_to_add
= 0;
8883 *padded_scratches
= 0;
8885 /* If PAT is a PARALLEL, check to see if it contains the CLOBBER
8886 we use to indicate that something didn't match. If we find such a
8887 thing, force rejection. */
8888 if (GET_CODE (pat
) == PARALLEL
)
8889 for (i
= XVECLEN (pat
, 0) - 1; i
>= 0; i
--)
8890 if (GET_CODE (XVECEXP (pat
, 0, i
)) == CLOBBER
8891 && XEXP (XVECEXP (pat
, 0, i
), 0) == const0_rtx
)
8894 /* Is the result of combination a valid instruction? */
8895 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
8897 /* If it isn't, there is the possibility that we previously had an insn
8898 that clobbered some register as a side effect, but the combined
8899 insn doesn't need to do that. So try once more without the clobbers
8900 unless this represents an ASM insn. */
8902 if (insn_code_number
< 0 && ! check_asm_operands (pat
)
8903 && GET_CODE (pat
) == PARALLEL
)
8907 for (pos
= 0, i
= 0; i
< XVECLEN (pat
, 0); i
++)
8908 if (GET_CODE (XVECEXP (pat
, 0, i
)) != CLOBBER
)
8911 SUBST (XVECEXP (pat
, 0, pos
), XVECEXP (pat
, 0, i
));
8915 SUBST_INT (XVECLEN (pat
, 0), pos
);
8918 pat
= XVECEXP (pat
, 0, 0);
8920 insn_code_number
= recog (pat
, insn
, &num_clobbers_to_add
);
8923 /* If we had any clobbers to add, make a new pattern than contains
8924 them. Then check to make sure that all of them are dead. */
8925 if (num_clobbers_to_add
)
8927 rtx newpat
= gen_rtx (PARALLEL
, VOIDmode
,
8928 gen_rtvec (GET_CODE (pat
) == PARALLEL
8929 ? XVECLEN (pat
, 0) + num_clobbers_to_add
8930 : num_clobbers_to_add
+ 1));
8932 if (GET_CODE (pat
) == PARALLEL
)
8933 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
8934 XVECEXP (newpat
, 0, i
) = XVECEXP (pat
, 0, i
);
8936 XVECEXP (newpat
, 0, 0) = pat
;
8938 add_clobbers (newpat
, insn_code_number
);
8940 for (i
= XVECLEN (newpat
, 0) - num_clobbers_to_add
;
8941 i
< XVECLEN (newpat
, 0); i
++)
8943 if (GET_CODE (XEXP (XVECEXP (newpat
, 0, i
), 0)) == REG
8944 && ! reg_dead_at_p (XEXP (XVECEXP (newpat
, 0, i
), 0), insn
))
8946 else if (GET_CODE (XEXP (XVECEXP (newpat
, 0, i
), 0)) == SCRATCH
)
8947 (*padded_scratches
)++;
8948 notes
= gen_rtx (EXPR_LIST
, REG_UNUSED
,
8949 XEXP (XVECEXP (newpat
, 0, i
), 0), notes
);
8957 return insn_code_number
;
8960 /* Like gen_lowpart but for use by combine. In combine it is not possible
8961 to create any new pseudoregs. However, it is safe to create
8962 invalid memory addresses, because combine will try to recognize
8963 them and all they will do is make the combine attempt fail.
8965 If for some reason this cannot do its job, an rtx
8966 (clobber (const_int 0)) is returned.
8967 An insn containing that will not be recognized. */
8972 gen_lowpart_for_combine (mode
, x
)
8973 enum machine_mode mode
;
8978 if (GET_MODE (x
) == mode
)
8981 /* We can only support MODE being wider than a word if X is a
8982 constant integer or has a mode the same size. */
8984 if (GET_MODE_SIZE (mode
) > UNITS_PER_WORD
8985 && ! ((GET_MODE (x
) == VOIDmode
8986 && (GET_CODE (x
) == CONST_INT
8987 || GET_CODE (x
) == CONST_DOUBLE
))
8988 || GET_MODE_SIZE (GET_MODE (x
)) == GET_MODE_SIZE (mode
)))
8989 return gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
);
8991 /* X might be a paradoxical (subreg (mem)). In that case, gen_lowpart
8992 won't know what to do. So we will strip off the SUBREG here and
8993 process normally. */
8994 if (GET_CODE (x
) == SUBREG
&& GET_CODE (SUBREG_REG (x
)) == MEM
)
8997 if (GET_MODE (x
) == mode
)
9001 result
= gen_lowpart_common (mode
, x
);
9003 && GET_CODE (result
) == SUBREG
9004 && GET_CODE (SUBREG_REG (result
)) == REG
9005 && REGNO (SUBREG_REG (result
)) >= FIRST_PSEUDO_REGISTER
9006 && (GET_MODE_SIZE (GET_MODE (result
))
9007 != GET_MODE_SIZE (GET_MODE (SUBREG_REG (result
)))))
9008 REG_CHANGES_SIZE (REGNO (SUBREG_REG (result
))) = 1;
9013 if (GET_CODE (x
) == MEM
)
9015 register int offset
= 0;
9018 /* Refuse to work on a volatile memory ref or one with a mode-dependent
9020 if (MEM_VOLATILE_P (x
) || mode_dependent_address_p (XEXP (x
, 0)))
9021 return gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
);
9023 /* If we want to refer to something bigger than the original memref,
9024 generate a perverse subreg instead. That will force a reload
9025 of the original memref X. */
9026 if (GET_MODE_SIZE (GET_MODE (x
)) < GET_MODE_SIZE (mode
))
9027 return gen_rtx (SUBREG
, mode
, x
, 0);
9029 if (WORDS_BIG_ENDIAN
)
9030 offset
= (MAX (GET_MODE_SIZE (GET_MODE (x
)), UNITS_PER_WORD
)
9031 - MAX (GET_MODE_SIZE (mode
), UNITS_PER_WORD
));
9032 if (BYTES_BIG_ENDIAN
)
9034 /* Adjust the address so that the address-after-the-data is
9036 offset
-= (MIN (UNITS_PER_WORD
, GET_MODE_SIZE (mode
))
9037 - MIN (UNITS_PER_WORD
, GET_MODE_SIZE (GET_MODE (x
))));
9039 new = gen_rtx (MEM
, mode
, plus_constant (XEXP (x
, 0), offset
));
9040 RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x
);
9041 MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x
);
9042 MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x
);
9046 /* If X is a comparison operator, rewrite it in a new mode. This
9047 probably won't match, but may allow further simplifications. */
9048 else if (GET_RTX_CLASS (GET_CODE (x
)) == '<')
9049 return gen_rtx_combine (GET_CODE (x
), mode
, XEXP (x
, 0), XEXP (x
, 1));
9051 /* If we couldn't simplify X any other way, just enclose it in a
9052 SUBREG. Normally, this SUBREG won't match, but some patterns may
9053 include an explicit SUBREG or we may simplify it further in combine. */
9058 if (WORDS_BIG_ENDIAN
&& GET_MODE_SIZE (GET_MODE (x
)) > UNITS_PER_WORD
)
9059 word
= ((GET_MODE_SIZE (GET_MODE (x
))
9060 - MAX (GET_MODE_SIZE (mode
), UNITS_PER_WORD
))
9062 return gen_rtx (SUBREG
, mode
, x
, word
);
9066 /* Make an rtx expression. This is a subset of gen_rtx and only supports
9067 expressions of 1, 2, or 3 operands, each of which are rtx expressions.
9069 If the identical expression was previously in the insn (in the undobuf),
9070 it will be returned. Only if it is not found will a new expression
9075 gen_rtx_combine
VPROTO((enum rtx_code code
, enum machine_mode mode
, ...))
9079 enum machine_mode mode
;
9092 code
= va_arg (p
, enum rtx_code
);
9093 mode
= va_arg (p
, enum machine_mode
);
9096 n_args
= GET_RTX_LENGTH (code
);
9097 fmt
= GET_RTX_FORMAT (code
);
9099 if (n_args
== 0 || n_args
> 3)
9102 /* Get each arg and verify that it is supposed to be an expression. */
9103 for (j
= 0; j
< n_args
; j
++)
9108 args
[j
] = va_arg (p
, rtx
);
9111 /* See if this is in undobuf. Be sure we don't use objects that came
9112 from another insn; this could produce circular rtl structures. */
9114 for (undo
= undobuf
.undos
; undo
!= undobuf
.previous_undos
; undo
= undo
->next
)
9116 && GET_CODE (undo
->old_contents
.r
) == code
9117 && GET_MODE (undo
->old_contents
.r
) == mode
)
9119 for (j
= 0; j
< n_args
; j
++)
9120 if (XEXP (undo
->old_contents
.r
, j
) != args
[j
])
9124 return undo
->old_contents
.r
;
9127 /* Otherwise make a new rtx. We know we have 1, 2, or 3 args.
9128 Use rtx_alloc instead of gen_rtx because it's faster on RISC. */
9129 rt
= rtx_alloc (code
);
9130 PUT_MODE (rt
, mode
);
9131 XEXP (rt
, 0) = args
[0];
9134 XEXP (rt
, 1) = args
[1];
9136 XEXP (rt
, 2) = args
[2];
9141 /* These routines make binary and unary operations by first seeing if they
9142 fold; if not, a new expression is allocated. */
9145 gen_binary (code
, mode
, op0
, op1
)
9147 enum machine_mode mode
;
9153 if (GET_RTX_CLASS (code
) == 'c'
9154 && (GET_CODE (op0
) == CONST_INT
9155 || (CONSTANT_P (op0
) && GET_CODE (op1
) != CONST_INT
)))
9156 tem
= op0
, op0
= op1
, op1
= tem
;
9158 if (GET_RTX_CLASS (code
) == '<')
9160 enum machine_mode op_mode
= GET_MODE (op0
);
9162 /* Strip the COMPARE from (REL_OP (compare X Y) 0) to get
9163 just (REL_OP X Y). */
9164 if (GET_CODE (op0
) == COMPARE
&& op1
== const0_rtx
)
9166 op1
= XEXP (op0
, 1);
9167 op0
= XEXP (op0
, 0);
9168 op_mode
= GET_MODE (op0
);
9171 if (op_mode
== VOIDmode
)
9172 op_mode
= GET_MODE (op1
);
9173 result
= simplify_relational_operation (code
, op_mode
, op0
, op1
);
9176 result
= simplify_binary_operation (code
, mode
, op0
, op1
);
9181 /* Put complex operands first and constants second. */
9182 if (GET_RTX_CLASS (code
) == 'c'
9183 && ((CONSTANT_P (op0
) && GET_CODE (op1
) != CONST_INT
)
9184 || (GET_RTX_CLASS (GET_CODE (op0
)) == 'o'
9185 && GET_RTX_CLASS (GET_CODE (op1
)) != 'o')
9186 || (GET_CODE (op0
) == SUBREG
9187 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (op0
))) == 'o'
9188 && GET_RTX_CLASS (GET_CODE (op1
)) != 'o')))
9189 return gen_rtx_combine (code
, mode
, op1
, op0
);
9191 return gen_rtx_combine (code
, mode
, op0
, op1
);
9195 gen_unary (code
, mode
, op0_mode
, op0
)
9197 enum machine_mode mode
, op0_mode
;
9200 rtx result
= simplify_unary_operation (code
, mode
, op0
, op0_mode
);
9205 return gen_rtx_combine (code
, mode
, op0
);
9208 /* Simplify a comparison between *POP0 and *POP1 where CODE is the
9209 comparison code that will be tested.
9211 The result is a possibly different comparison code to use. *POP0 and
9212 *POP1 may be updated.
9214 It is possible that we might detect that a comparison is either always
9215 true or always false. However, we do not perform general constant
9216 folding in combine, so this knowledge isn't useful. Such tautologies
9217 should have been detected earlier. Hence we ignore all such cases. */
9219 static enum rtx_code
9220 simplify_comparison (code
, pop0
, pop1
)
9229 enum machine_mode mode
, tmode
;
9231 /* Try a few ways of applying the same transformation to both operands. */
9234 #ifndef WORD_REGISTER_OPERATIONS
9235 /* The test below this one won't handle SIGN_EXTENDs on these machines,
9236 so check specially. */
9237 if (code
!= GTU
&& code
!= GEU
&& code
!= LTU
&& code
!= LEU
9238 && GET_CODE (op0
) == ASHIFTRT
&& GET_CODE (op1
) == ASHIFTRT
9239 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
9240 && GET_CODE (XEXP (op1
, 0)) == ASHIFT
9241 && GET_CODE (XEXP (XEXP (op0
, 0), 0)) == SUBREG
9242 && GET_CODE (XEXP (XEXP (op1
, 0), 0)) == SUBREG
9243 && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0)))
9244 == GET_MODE (SUBREG_REG (XEXP (XEXP (op1
, 0), 0))))
9245 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9246 && GET_CODE (XEXP (op1
, 1)) == CONST_INT
9247 && GET_CODE (XEXP (XEXP (op0
, 0), 1)) == CONST_INT
9248 && GET_CODE (XEXP (XEXP (op1
, 0), 1)) == CONST_INT
9249 && INTVAL (XEXP (op0
, 1)) == INTVAL (XEXP (op1
, 1))
9250 && INTVAL (XEXP (op0
, 1)) == INTVAL (XEXP (XEXP (op0
, 0), 1))
9251 && INTVAL (XEXP (op0
, 1)) == INTVAL (XEXP (XEXP (op1
, 0), 1))
9252 && (INTVAL (XEXP (op0
, 1))
9253 == (GET_MODE_BITSIZE (GET_MODE (op0
))
9255 (GET_MODE (SUBREG_REG (XEXP (XEXP (op0
, 0), 0))))))))
9257 op0
= SUBREG_REG (XEXP (XEXP (op0
, 0), 0));
9258 op1
= SUBREG_REG (XEXP (XEXP (op1
, 0), 0));
9262 /* If both operands are the same constant shift, see if we can ignore the
9263 shift. We can if the shift is a rotate or if the bits shifted out of
9264 this shift are known to be zero for both inputs and if the type of
9265 comparison is compatible with the shift. */
9266 if (GET_CODE (op0
) == GET_CODE (op1
)
9267 && GET_MODE_BITSIZE (GET_MODE (op0
)) <= HOST_BITS_PER_WIDE_INT
9268 && ((GET_CODE (op0
) == ROTATE
&& (code
== NE
|| code
== EQ
))
9269 || ((GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFT
)
9270 && (code
!= GT
&& code
!= LT
&& code
!= GE
&& code
!= LE
))
9271 || (GET_CODE (op0
) == ASHIFTRT
9272 && (code
!= GTU
&& code
!= LTU
9273 && code
!= GEU
&& code
!= GEU
)))
9274 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9275 && INTVAL (XEXP (op0
, 1)) >= 0
9276 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
9277 && XEXP (op0
, 1) == XEXP (op1
, 1))
9279 enum machine_mode mode
= GET_MODE (op0
);
9280 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
9281 int shift_count
= INTVAL (XEXP (op0
, 1));
9283 if (GET_CODE (op0
) == LSHIFTRT
|| GET_CODE (op0
) == ASHIFTRT
)
9284 mask
&= (mask
>> shift_count
) << shift_count
;
9285 else if (GET_CODE (op0
) == ASHIFT
)
9286 mask
= (mask
& (mask
<< shift_count
)) >> shift_count
;
9288 if ((nonzero_bits (XEXP (op0
, 0), mode
) & ~ mask
) == 0
9289 && (nonzero_bits (XEXP (op1
, 0), mode
) & ~ mask
) == 0)
9290 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0);
9295 /* If both operands are AND's of a paradoxical SUBREG by constant, the
9296 SUBREGs are of the same mode, and, in both cases, the AND would
9297 be redundant if the comparison was done in the narrower mode,
9298 do the comparison in the narrower mode (e.g., we are AND'ing with 1
9299 and the operand's possibly nonzero bits are 0xffffff01; in that case
9300 if we only care about QImode, we don't need the AND). This case
9301 occurs if the output mode of an scc insn is not SImode and
9302 STORE_FLAG_VALUE == 1 (e.g., the 386).
9304 Similarly, check for a case where the AND's are ZERO_EXTEND
9305 operations from some narrower mode even though a SUBREG is not
9308 else if (GET_CODE (op0
) == AND
&& GET_CODE (op1
) == AND
9309 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9310 && GET_CODE (XEXP (op1
, 1)) == CONST_INT
)
9312 rtx inner_op0
= XEXP (op0
, 0);
9313 rtx inner_op1
= XEXP (op1
, 0);
9314 HOST_WIDE_INT c0
= INTVAL (XEXP (op0
, 1));
9315 HOST_WIDE_INT c1
= INTVAL (XEXP (op1
, 1));
9318 if (GET_CODE (inner_op0
) == SUBREG
&& GET_CODE (inner_op1
) == SUBREG
9319 && (GET_MODE_SIZE (GET_MODE (inner_op0
))
9320 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (inner_op0
))))
9321 && (GET_MODE (SUBREG_REG (inner_op0
))
9322 == GET_MODE (SUBREG_REG (inner_op1
)))
9323 && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0
)))
9324 <= HOST_BITS_PER_WIDE_INT
)
9325 && (0 == ((~c0
) & nonzero_bits (SUBREG_REG (inner_op0
),
9326 GET_MODE (SUBREG_REG (op0
)))))
9327 && (0 == ((~c1
) & nonzero_bits (SUBREG_REG (inner_op1
),
9328 GET_MODE (SUBREG_REG (inner_op1
))))))
9330 op0
= SUBREG_REG (inner_op0
);
9331 op1
= SUBREG_REG (inner_op1
);
9333 /* The resulting comparison is always unsigned since we masked
9334 off the original sign bit. */
9335 code
= unsigned_condition (code
);
9341 for (tmode
= GET_CLASS_NARROWEST_MODE
9342 (GET_MODE_CLASS (GET_MODE (op0
)));
9343 tmode
!= GET_MODE (op0
); tmode
= GET_MODE_WIDER_MODE (tmode
))
9344 if (c0
== GET_MODE_MASK (tmode
))
9346 op0
= gen_lowpart_for_combine (tmode
, inner_op0
);
9347 op1
= gen_lowpart_for_combine (tmode
, inner_op1
);
9348 code
= unsigned_condition (code
);
9357 /* If both operands are NOT, we can strip off the outer operation
9358 and adjust the comparison code for swapped operands; similarly for
9359 NEG, except that this must be an equality comparison. */
9360 else if ((GET_CODE (op0
) == NOT
&& GET_CODE (op1
) == NOT
)
9361 || (GET_CODE (op0
) == NEG
&& GET_CODE (op1
) == NEG
9362 && (code
== EQ
|| code
== NE
)))
9363 op0
= XEXP (op0
, 0), op1
= XEXP (op1
, 0), code
= swap_condition (code
);
9369 /* If the first operand is a constant, swap the operands and adjust the
9370 comparison code appropriately, but don't do this if the second operand
9371 is already a constant integer. */
9372 if (CONSTANT_P (op0
) && GET_CODE (op1
) != CONST_INT
)
9374 tem
= op0
, op0
= op1
, op1
= tem
;
9375 code
= swap_condition (code
);
9378 /* We now enter a loop during which we will try to simplify the comparison.
9379 For the most part, we only are concerned with comparisons with zero,
9380 but some things may really be comparisons with zero but not start
9381 out looking that way. */
9383 while (GET_CODE (op1
) == CONST_INT
)
9385 enum machine_mode mode
= GET_MODE (op0
);
9386 int mode_width
= GET_MODE_BITSIZE (mode
);
9387 unsigned HOST_WIDE_INT mask
= GET_MODE_MASK (mode
);
9388 int equality_comparison_p
;
9389 int sign_bit_comparison_p
;
9390 int unsigned_comparison_p
;
9391 HOST_WIDE_INT const_op
;
9393 /* We only want to handle integral modes. This catches VOIDmode,
9394 CCmode, and the floating-point modes. An exception is that we
9395 can handle VOIDmode if OP0 is a COMPARE or a comparison
9398 if (GET_MODE_CLASS (mode
) != MODE_INT
9399 && ! (mode
== VOIDmode
9400 && (GET_CODE (op0
) == COMPARE
9401 || GET_RTX_CLASS (GET_CODE (op0
)) == '<')))
9404 /* Get the constant we are comparing against and turn off all bits
9405 not on in our mode. */
9406 const_op
= INTVAL (op1
);
9407 if (mode_width
<= HOST_BITS_PER_WIDE_INT
)
9410 /* If we are comparing against a constant power of two and the value
9411 being compared can only have that single bit nonzero (e.g., it was
9412 `and'ed with that bit), we can replace this with a comparison
9415 && (code
== EQ
|| code
== NE
|| code
== GE
|| code
== GEU
9416 || code
== LT
|| code
== LTU
)
9417 && mode_width
<= HOST_BITS_PER_WIDE_INT
9418 && exact_log2 (const_op
) >= 0
9419 && nonzero_bits (op0
, mode
) == const_op
)
9421 code
= (code
== EQ
|| code
== GE
|| code
== GEU
? NE
: EQ
);
9422 op1
= const0_rtx
, const_op
= 0;
9425 /* Similarly, if we are comparing a value known to be either -1 or
9426 0 with -1, change it to the opposite comparison against zero. */
9429 && (code
== EQ
|| code
== NE
|| code
== GT
|| code
== LE
9430 || code
== GEU
|| code
== LTU
)
9431 && num_sign_bit_copies (op0
, mode
) == mode_width
)
9433 code
= (code
== EQ
|| code
== LE
|| code
== GEU
? NE
: EQ
);
9434 op1
= const0_rtx
, const_op
= 0;
9437 /* Do some canonicalizations based on the comparison code. We prefer
9438 comparisons against zero and then prefer equality comparisons.
9439 If we can reduce the size of a constant, we will do that too. */
9444 /* < C is equivalent to <= (C - 1) */
9448 op1
= GEN_INT (const_op
);
9450 /* ... fall through to LE case below. */
9456 /* <= C is equivalent to < (C + 1); we do this for C < 0 */
9460 op1
= GEN_INT (const_op
);
9464 /* If we are doing a <= 0 comparison on a value known to have
9465 a zero sign bit, we can replace this with == 0. */
9466 else if (const_op
== 0
9467 && mode_width
<= HOST_BITS_PER_WIDE_INT
9468 && (nonzero_bits (op0
, mode
)
9469 & ((HOST_WIDE_INT
) 1 << (mode_width
- 1))) == 0)
9474 /* >= C is equivalent to > (C - 1). */
9478 op1
= GEN_INT (const_op
);
9480 /* ... fall through to GT below. */
9486 /* > C is equivalent to >= (C + 1); we do this for C < 0*/
9490 op1
= GEN_INT (const_op
);
9494 /* If we are doing a > 0 comparison on a value known to have
9495 a zero sign bit, we can replace this with != 0. */
9496 else if (const_op
== 0
9497 && mode_width
<= HOST_BITS_PER_WIDE_INT
9498 && (nonzero_bits (op0
, mode
)
9499 & ((HOST_WIDE_INT
) 1 << (mode_width
- 1))) == 0)
9504 /* < C is equivalent to <= (C - 1). */
9508 op1
= GEN_INT (const_op
);
9510 /* ... fall through ... */
9513 /* (unsigned) < 0x80000000 is equivalent to >= 0. */
9514 else if ((mode_width
<= HOST_BITS_PER_WIDE_INT
)
9515 && (const_op
== (HOST_WIDE_INT
) 1 << (mode_width
- 1)))
9517 const_op
= 0, op1
= const0_rtx
;
9525 /* unsigned <= 0 is equivalent to == 0 */
9529 /* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
9530 else if ((mode_width
<= HOST_BITS_PER_WIDE_INT
)
9531 && (const_op
== ((HOST_WIDE_INT
) 1 << (mode_width
- 1)) - 1))
9533 const_op
= 0, op1
= const0_rtx
;
9539 /* >= C is equivalent to < (C - 1). */
9543 op1
= GEN_INT (const_op
);
9545 /* ... fall through ... */
9548 /* (unsigned) >= 0x80000000 is equivalent to < 0. */
9549 else if ((mode_width
<= HOST_BITS_PER_WIDE_INT
)
9550 && (const_op
== (HOST_WIDE_INT
) 1 << (mode_width
- 1)))
9552 const_op
= 0, op1
= const0_rtx
;
9560 /* unsigned > 0 is equivalent to != 0 */
9564 /* (unsigned) > 0x7fffffff is equivalent to < 0. */
9565 else if ((mode_width
<= HOST_BITS_PER_WIDE_INT
)
9566 && (const_op
== ((HOST_WIDE_INT
) 1 << (mode_width
- 1)) - 1))
9568 const_op
= 0, op1
= const0_rtx
;
9577 /* Compute some predicates to simplify code below. */
9579 equality_comparison_p
= (code
== EQ
|| code
== NE
);
9580 sign_bit_comparison_p
= ((code
== LT
|| code
== GE
) && const_op
== 0);
9581 unsigned_comparison_p
= (code
== LTU
|| code
== LEU
|| code
== GTU
9584 /* If this is a sign bit comparison and we can do arithmetic in
9585 MODE, say that we will only be needing the sign bit of OP0. */
9586 if (sign_bit_comparison_p
9587 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
)
9588 op0
= force_to_mode (op0
, mode
,
9590 << (GET_MODE_BITSIZE (mode
) - 1)),
9593 /* Now try cases based on the opcode of OP0. If none of the cases
9594 does a "continue", we exit this loop immediately after the
9597 switch (GET_CODE (op0
))
9600 /* If we are extracting a single bit from a variable position in
9601 a constant that has only a single bit set and are comparing it
9602 with zero, we can convert this into an equality comparison
9603 between the position and the location of the single bit. */
9605 if (GET_CODE (XEXP (op0
, 0)) == CONST_INT
9606 && XEXP (op0
, 1) == const1_rtx
9607 && equality_comparison_p
&& const_op
== 0
9608 && (i
= exact_log2 (INTVAL (XEXP (op0
, 0)))) >= 0)
9610 if (BITS_BIG_ENDIAN
)
9612 i
= (GET_MODE_BITSIZE
9613 (insn_operand_mode
[(int) CODE_FOR_extzv
][1]) - 1 - i
);
9615 i
= BITS_PER_WORD
- 1 - i
;
9618 op0
= XEXP (op0
, 2);
9622 /* Result is nonzero iff shift count is equal to I. */
9623 code
= reverse_condition (code
);
9627 /* ... fall through ... */
9630 tem
= expand_compound_operation (op0
);
9639 /* If testing for equality, we can take the NOT of the constant. */
9640 if (equality_comparison_p
9641 && (tem
= simplify_unary_operation (NOT
, mode
, op1
, mode
)) != 0)
9643 op0
= XEXP (op0
, 0);
9648 /* If just looking at the sign bit, reverse the sense of the
9650 if (sign_bit_comparison_p
)
9652 op0
= XEXP (op0
, 0);
9653 code
= (code
== GE
? LT
: GE
);
9659 /* If testing for equality, we can take the NEG of the constant. */
9660 if (equality_comparison_p
9661 && (tem
= simplify_unary_operation (NEG
, mode
, op1
, mode
)) != 0)
9663 op0
= XEXP (op0
, 0);
9668 /* The remaining cases only apply to comparisons with zero. */
9672 /* When X is ABS or is known positive,
9673 (neg X) is < 0 if and only if X != 0. */
9675 if (sign_bit_comparison_p
9676 && (GET_CODE (XEXP (op0
, 0)) == ABS
9677 || (mode_width
<= HOST_BITS_PER_WIDE_INT
9678 && (nonzero_bits (XEXP (op0
, 0), mode
)
9679 & ((HOST_WIDE_INT
) 1 << (mode_width
- 1))) == 0)))
9681 op0
= XEXP (op0
, 0);
9682 code
= (code
== LT
? NE
: EQ
);
9686 /* If we have NEG of something whose two high-order bits are the
9687 same, we know that "(-a) < 0" is equivalent to "a > 0". */
9688 if (num_sign_bit_copies (op0
, mode
) >= 2)
9690 op0
= XEXP (op0
, 0);
9691 code
= swap_condition (code
);
9697 /* If we are testing equality and our count is a constant, we
9698 can perform the inverse operation on our RHS. */
9699 if (equality_comparison_p
&& GET_CODE (XEXP (op0
, 1)) == CONST_INT
9700 && (tem
= simplify_binary_operation (ROTATERT
, mode
,
9701 op1
, XEXP (op0
, 1))) != 0)
9703 op0
= XEXP (op0
, 0);
9708 /* If we are doing a < 0 or >= 0 comparison, it means we are testing
9709 a particular bit. Convert it to an AND of a constant of that
9710 bit. This will be converted into a ZERO_EXTRACT. */
9711 if (const_op
== 0 && sign_bit_comparison_p
9712 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9713 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
9715 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
9718 - INTVAL (XEXP (op0
, 1)))));
9719 code
= (code
== LT
? NE
: EQ
);
9723 /* ... fall through ... */
9726 /* ABS is ignorable inside an equality comparison with zero. */
9727 if (const_op
== 0 && equality_comparison_p
)
9729 op0
= XEXP (op0
, 0);
9736 /* Can simplify (compare (zero/sign_extend FOO) CONST)
9737 to (compare FOO CONST) if CONST fits in FOO's mode and we
9738 are either testing inequality or have an unsigned comparison
9739 with ZERO_EXTEND or a signed comparison with SIGN_EXTEND. */
9740 if (! unsigned_comparison_p
9741 && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0
, 0)))
9742 <= HOST_BITS_PER_WIDE_INT
)
9743 && ((unsigned HOST_WIDE_INT
) const_op
9744 < (((HOST_WIDE_INT
) 1
9745 << (GET_MODE_BITSIZE (GET_MODE (XEXP (op0
, 0))) - 1)))))
9747 op0
= XEXP (op0
, 0);
9753 /* Check for the case where we are comparing A - C1 with C2,
9754 both constants are smaller than 1/2 the maximum positive
9755 value in MODE, and the comparison is equality or unsigned.
9756 In that case, if A is either zero-extended to MODE or has
9757 sufficient sign bits so that the high-order bit in MODE
9758 is a copy of the sign in the inner mode, we can prove that it is
9759 safe to do the operation in the wider mode. This simplifies
9760 many range checks. */
9762 if (mode_width
<= HOST_BITS_PER_WIDE_INT
9763 && subreg_lowpart_p (op0
)
9764 && GET_CODE (SUBREG_REG (op0
)) == PLUS
9765 && GET_CODE (XEXP (SUBREG_REG (op0
), 1)) == CONST_INT
9766 && INTVAL (XEXP (SUBREG_REG (op0
), 1)) < 0
9767 && (- INTVAL (XEXP (SUBREG_REG (op0
), 1))
9768 < GET_MODE_MASK (mode
) / 2)
9769 && (unsigned HOST_WIDE_INT
) const_op
< GET_MODE_MASK (mode
) / 2
9770 && (0 == (nonzero_bits (XEXP (SUBREG_REG (op0
), 0),
9771 GET_MODE (SUBREG_REG (op0
)))
9772 & ~ GET_MODE_MASK (mode
))
9773 || (num_sign_bit_copies (XEXP (SUBREG_REG (op0
), 0),
9774 GET_MODE (SUBREG_REG (op0
)))
9775 > (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0
)))
9776 - GET_MODE_BITSIZE (mode
)))))
9778 op0
= SUBREG_REG (op0
);
9782 /* If the inner mode is narrower and we are extracting the low part,
9783 we can treat the SUBREG as if it were a ZERO_EXTEND. */
9784 if (subreg_lowpart_p (op0
)
9785 && GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0
))) < mode_width
)
9786 /* Fall through */ ;
9790 /* ... fall through ... */
9793 if ((unsigned_comparison_p
|| equality_comparison_p
)
9794 && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0
, 0)))
9795 <= HOST_BITS_PER_WIDE_INT
)
9796 && ((unsigned HOST_WIDE_INT
) const_op
9797 < GET_MODE_MASK (GET_MODE (XEXP (op0
, 0)))))
9799 op0
= XEXP (op0
, 0);
9805 /* (eq (plus X A) B) -> (eq X (minus B A)). We can only do
9806 this for equality comparisons due to pathological cases involving
9808 if (equality_comparison_p
9809 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
9810 op1
, XEXP (op0
, 1))))
9812 op0
= XEXP (op0
, 0);
9817 /* (plus (abs X) (const_int -1)) is < 0 if and only if X == 0. */
9818 if (const_op
== 0 && XEXP (op0
, 1) == constm1_rtx
9819 && GET_CODE (XEXP (op0
, 0)) == ABS
&& sign_bit_comparison_p
)
9821 op0
= XEXP (XEXP (op0
, 0), 0);
9822 code
= (code
== LT
? EQ
: NE
);
9828 /* (eq (minus A B) C) -> (eq A (plus B C)) or
9829 (eq B (minus A C)), whichever simplifies. We can only do
9830 this for equality comparisons due to pathological cases involving
9832 if (equality_comparison_p
9833 && 0 != (tem
= simplify_binary_operation (PLUS
, mode
,
9834 XEXP (op0
, 1), op1
)))
9836 op0
= XEXP (op0
, 0);
9841 if (equality_comparison_p
9842 && 0 != (tem
= simplify_binary_operation (MINUS
, mode
,
9843 XEXP (op0
, 0), op1
)))
9845 op0
= XEXP (op0
, 1);
9850 /* The sign bit of (minus (ashiftrt X C) X), where C is the number
9851 of bits in X minus 1, is one iff X > 0. */
9852 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == ASHIFTRT
9853 && GET_CODE (XEXP (XEXP (op0
, 0), 1)) == CONST_INT
9854 && INTVAL (XEXP (XEXP (op0
, 0), 1)) == mode_width
- 1
9855 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
9857 op0
= XEXP (op0
, 1);
9858 code
= (code
== GE
? LE
: GT
);
9864 /* (eq (xor A B) C) -> (eq A (xor B C)). This is a simplification
9865 if C is zero or B is a constant. */
9866 if (equality_comparison_p
9867 && 0 != (tem
= simplify_binary_operation (XOR
, mode
,
9868 XEXP (op0
, 1), op1
)))
9870 op0
= XEXP (op0
, 0);
9877 case LT
: case LTU
: case LE
: case LEU
:
9878 case GT
: case GTU
: case GE
: case GEU
:
9879 /* We can't do anything if OP0 is a condition code value, rather
9880 than an actual data value. */
9883 || XEXP (op0
, 0) == cc0_rtx
9885 || GET_MODE_CLASS (GET_MODE (XEXP (op0
, 0))) == MODE_CC
)
9888 /* Get the two operands being compared. */
9889 if (GET_CODE (XEXP (op0
, 0)) == COMPARE
)
9890 tem
= XEXP (XEXP (op0
, 0), 0), tem1
= XEXP (XEXP (op0
, 0), 1);
9892 tem
= XEXP (op0
, 0), tem1
= XEXP (op0
, 1);
9894 /* Check for the cases where we simply want the result of the
9895 earlier test or the opposite of that result. */
9897 || (code
== EQ
&& reversible_comparison_p (op0
))
9898 || (GET_MODE_BITSIZE (GET_MODE (op0
)) <= HOST_BITS_PER_WIDE_INT
9899 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
9900 && (STORE_FLAG_VALUE
9901 & (((HOST_WIDE_INT
) 1
9902 << (GET_MODE_BITSIZE (GET_MODE (op0
)) - 1))))
9904 || (code
== GE
&& reversible_comparison_p (op0
)))))
9906 code
= (code
== LT
|| code
== NE
9907 ? GET_CODE (op0
) : reverse_condition (GET_CODE (op0
)));
9908 op0
= tem
, op1
= tem1
;
9914 /* The sign bit of (ior (plus X (const_int -1)) X) is non-zero
9916 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 0)) == PLUS
9917 && XEXP (XEXP (op0
, 0), 1) == constm1_rtx
9918 && rtx_equal_p (XEXP (XEXP (op0
, 0), 0), XEXP (op0
, 1)))
9920 op0
= XEXP (op0
, 1);
9921 code
= (code
== GE
? GT
: LE
);
9927 /* Convert (and (xshift 1 X) Y) to (and (lshiftrt Y X) 1). This
9928 will be converted to a ZERO_EXTRACT later. */
9929 if (const_op
== 0 && equality_comparison_p
9930 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
9931 && XEXP (XEXP (op0
, 0), 0) == const1_rtx
)
9933 op0
= simplify_and_const_int
9934 (op0
, mode
, gen_rtx_combine (LSHIFTRT
, mode
,
9936 XEXP (XEXP (op0
, 0), 1)),
9941 /* If we are comparing (and (lshiftrt X C1) C2) for equality with
9942 zero and X is a comparison and C1 and C2 describe only bits set
9943 in STORE_FLAG_VALUE, we can compare with X. */
9944 if (const_op
== 0 && equality_comparison_p
9945 && mode_width
<= HOST_BITS_PER_WIDE_INT
9946 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9947 && GET_CODE (XEXP (op0
, 0)) == LSHIFTRT
9948 && GET_CODE (XEXP (XEXP (op0
, 0), 1)) == CONST_INT
9949 && INTVAL (XEXP (XEXP (op0
, 0), 1)) >= 0
9950 && INTVAL (XEXP (XEXP (op0
, 0), 1)) < HOST_BITS_PER_WIDE_INT
)
9952 mask
= ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
9953 << INTVAL (XEXP (XEXP (op0
, 0), 1)));
9954 if ((~ STORE_FLAG_VALUE
& mask
) == 0
9955 && (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (op0
, 0), 0))) == '<'
9956 || ((tem
= get_last_value (XEXP (XEXP (op0
, 0), 0))) != 0
9957 && GET_RTX_CLASS (GET_CODE (tem
)) == '<')))
9959 op0
= XEXP (XEXP (op0
, 0), 0);
9964 /* If we are doing an equality comparison of an AND of a bit equal
9965 to the sign bit, replace this with a LT or GE comparison of
9966 the underlying value. */
9967 if (equality_comparison_p
9969 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9970 && mode_width
<= HOST_BITS_PER_WIDE_INT
9971 && ((INTVAL (XEXP (op0
, 1)) & GET_MODE_MASK (mode
))
9972 == (HOST_WIDE_INT
) 1 << (mode_width
- 1)))
9974 op0
= XEXP (op0
, 0);
9975 code
= (code
== EQ
? GE
: LT
);
9979 /* If this AND operation is really a ZERO_EXTEND from a narrower
9980 mode, the constant fits within that mode, and this is either an
9981 equality or unsigned comparison, try to do this comparison in
9982 the narrower mode. */
9983 if ((equality_comparison_p
|| unsigned_comparison_p
)
9984 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
9985 && (i
= exact_log2 ((INTVAL (XEXP (op0
, 1))
9986 & GET_MODE_MASK (mode
))
9988 && const_op
>> i
== 0
9989 && (tmode
= mode_for_size (i
, MODE_INT
, 1)) != BLKmode
)
9991 op0
= gen_lowpart_for_combine (tmode
, XEXP (op0
, 0));
9997 /* If we have (compare (ashift FOO N) (const_int C)) and
9998 the high order N bits of FOO (N+1 if an inequality comparison)
9999 are known to be zero, we can do this by comparing FOO with C
10000 shifted right N bits so long as the low-order N bits of C are
10002 if (GET_CODE (XEXP (op0
, 1)) == CONST_INT
10003 && INTVAL (XEXP (op0
, 1)) >= 0
10004 && ((INTVAL (XEXP (op0
, 1)) + ! equality_comparison_p
)
10005 < HOST_BITS_PER_WIDE_INT
)
10007 & (((HOST_WIDE_INT
) 1 << INTVAL (XEXP (op0
, 1))) - 1)) == 0)
10008 && mode_width
<= HOST_BITS_PER_WIDE_INT
10009 && (nonzero_bits (XEXP (op0
, 0), mode
)
10010 & ~ (mask
>> (INTVAL (XEXP (op0
, 1))
10011 + ! equality_comparison_p
))) == 0)
10013 const_op
>>= INTVAL (XEXP (op0
, 1));
10014 op1
= GEN_INT (const_op
);
10015 op0
= XEXP (op0
, 0);
10019 /* If we are doing a sign bit comparison, it means we are testing
10020 a particular bit. Convert it to the appropriate AND. */
10021 if (sign_bit_comparison_p
&& GET_CODE (XEXP (op0
, 1)) == CONST_INT
10022 && mode_width
<= HOST_BITS_PER_WIDE_INT
)
10024 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
10027 - INTVAL (XEXP (op0
, 1)))));
10028 code
= (code
== LT
? NE
: EQ
);
10032 /* If this an equality comparison with zero and we are shifting
10033 the low bit to the sign bit, we can convert this to an AND of the
10035 if (const_op
== 0 && equality_comparison_p
10036 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
10037 && INTVAL (XEXP (op0
, 1)) == mode_width
- 1)
10039 op0
= simplify_and_const_int (NULL_RTX
, mode
, XEXP (op0
, 0),
10040 (HOST_WIDE_INT
) 1);
10046 /* If this is an equality comparison with zero, we can do this
10047 as a logical shift, which might be much simpler. */
10048 if (equality_comparison_p
&& const_op
== 0
10049 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
)
10051 op0
= simplify_shift_const (NULL_RTX
, LSHIFTRT
, mode
,
10053 INTVAL (XEXP (op0
, 1)));
10057 /* If OP0 is a sign extension and CODE is not an unsigned comparison,
10058 do the comparison in a narrower mode. */
10059 if (! unsigned_comparison_p
10060 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
10061 && GET_CODE (XEXP (op0
, 0)) == ASHIFT
10062 && XEXP (op0
, 1) == XEXP (XEXP (op0
, 0), 1)
10063 && (tmode
= mode_for_size (mode_width
- INTVAL (XEXP (op0
, 1)),
10064 MODE_INT
, 1)) != BLKmode
10065 && ((unsigned HOST_WIDE_INT
) const_op
<= GET_MODE_MASK (tmode
)
10066 || ((unsigned HOST_WIDE_INT
) - const_op
10067 <= GET_MODE_MASK (tmode
))))
10069 op0
= gen_lowpart_for_combine (tmode
, XEXP (XEXP (op0
, 0), 0));
10073 /* ... fall through ... */
10075 /* If we have (compare (xshiftrt FOO N) (const_int C)) and
10076 the low order N bits of FOO are known to be zero, we can do this
10077 by comparing FOO with C shifted left N bits so long as no
10078 overflow occurs. */
10079 if (GET_CODE (XEXP (op0
, 1)) == CONST_INT
10080 && INTVAL (XEXP (op0
, 1)) >= 0
10081 && INTVAL (XEXP (op0
, 1)) < HOST_BITS_PER_WIDE_INT
10082 && mode_width
<= HOST_BITS_PER_WIDE_INT
10083 && (nonzero_bits (XEXP (op0
, 0), mode
)
10084 & (((HOST_WIDE_INT
) 1 << INTVAL (XEXP (op0
, 1))) - 1)) == 0
10086 || (floor_log2 (const_op
) + INTVAL (XEXP (op0
, 1))
10089 const_op
<<= INTVAL (XEXP (op0
, 1));
10090 op1
= GEN_INT (const_op
);
10091 op0
= XEXP (op0
, 0);
10095 /* If we are using this shift to extract just the sign bit, we
10096 can replace this with an LT or GE comparison. */
10098 && (equality_comparison_p
|| sign_bit_comparison_p
)
10099 && GET_CODE (XEXP (op0
, 1)) == CONST_INT
10100 && INTVAL (XEXP (op0
, 1)) == mode_width
- 1)
10102 op0
= XEXP (op0
, 0);
10103 code
= (code
== NE
|| code
== GT
? LT
: GE
);
10115 /* Now make any compound operations involved in this comparison. Then,
10116 check for an outmost SUBREG on OP0 that isn't doing anything or is
10117 paradoxical. The latter case can only occur when it is known that the
10118 "extra" bits will be zero. Therefore, it is safe to remove the SUBREG.
10119 We can never remove a SUBREG for a non-equality comparison because the
10120 sign bit is in a different place in the underlying object. */
10122 op0
= make_compound_operation (op0
, op1
== const0_rtx
? COMPARE
: SET
);
10123 op1
= make_compound_operation (op1
, SET
);
10125 if (GET_CODE (op0
) == SUBREG
&& subreg_lowpart_p (op0
)
10126 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
10127 && (code
== NE
|| code
== EQ
)
10128 && ((GET_MODE_SIZE (GET_MODE (op0
))
10129 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0
))))))
10131 op0
= SUBREG_REG (op0
);
10132 op1
= gen_lowpart_for_combine (GET_MODE (op0
), op1
);
10135 else if (GET_CODE (op0
) == SUBREG
&& subreg_lowpart_p (op0
)
10136 && GET_MODE_CLASS (GET_MODE (op0
)) == MODE_INT
10137 && (code
== NE
|| code
== EQ
)
10138 && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0
)))
10139 <= HOST_BITS_PER_WIDE_INT
)
10140 && (nonzero_bits (SUBREG_REG (op0
), GET_MODE (SUBREG_REG (op0
)))
10141 & ~ GET_MODE_MASK (GET_MODE (op0
))) == 0
10142 && (tem
= gen_lowpart_for_combine (GET_MODE (SUBREG_REG (op0
)),
10144 (nonzero_bits (tem
, GET_MODE (SUBREG_REG (op0
)))
10145 & ~ GET_MODE_MASK (GET_MODE (op0
))) == 0))
10146 op0
= SUBREG_REG (op0
), op1
= tem
;
10148 /* We now do the opposite procedure: Some machines don't have compare
10149 insns in all modes. If OP0's mode is an integer mode smaller than a
10150 word and we can't do a compare in that mode, see if there is a larger
10151 mode for which we can do the compare. There are a number of cases in
10152 which we can use the wider mode. */
10154 mode
= GET_MODE (op0
);
10155 if (mode
!= VOIDmode
&& GET_MODE_CLASS (mode
) == MODE_INT
10156 && GET_MODE_SIZE (mode
) < UNITS_PER_WORD
10157 && cmp_optab
->handlers
[(int) mode
].insn_code
== CODE_FOR_nothing
)
10158 for (tmode
= GET_MODE_WIDER_MODE (mode
);
10160 && GET_MODE_BITSIZE (tmode
) <= HOST_BITS_PER_WIDE_INT
);
10161 tmode
= GET_MODE_WIDER_MODE (tmode
))
10162 if (cmp_optab
->handlers
[(int) tmode
].insn_code
!= CODE_FOR_nothing
)
10164 /* If the only nonzero bits in OP0 and OP1 are those in the
10165 narrower mode and this is an equality or unsigned comparison,
10166 we can use the wider mode. Similarly for sign-extended
10167 values, in which case it is true for all comparisons. */
10168 if (((code
== EQ
|| code
== NE
10169 || code
== GEU
|| code
== GTU
|| code
== LEU
|| code
== LTU
)
10170 && (nonzero_bits (op0
, tmode
) & ~ GET_MODE_MASK (mode
)) == 0
10171 && (nonzero_bits (op1
, tmode
) & ~ GET_MODE_MASK (mode
)) == 0)
10172 || ((num_sign_bit_copies (op0
, tmode
)
10173 > GET_MODE_BITSIZE (tmode
) - GET_MODE_BITSIZE (mode
))
10174 && (num_sign_bit_copies (op1
, tmode
)
10175 > GET_MODE_BITSIZE (tmode
) - GET_MODE_BITSIZE (mode
))))
10177 op0
= gen_lowpart_for_combine (tmode
, op0
);
10178 op1
= gen_lowpart_for_combine (tmode
, op1
);
10182 /* If this is a test for negative, we can make an explicit
10183 test of the sign bit. */
10185 if (op1
== const0_rtx
&& (code
== LT
|| code
== GE
)
10186 && GET_MODE_BITSIZE (mode
) <= HOST_BITS_PER_WIDE_INT
)
10188 op0
= gen_binary (AND
, tmode
,
10189 gen_lowpart_for_combine (tmode
, op0
),
10190 GEN_INT ((HOST_WIDE_INT
) 1
10191 << (GET_MODE_BITSIZE (mode
) - 1)));
10192 code
= (code
== LT
) ? NE
: EQ
;
10197 #ifdef CANONICALIZE_COMPARISON
10198 /* If this machine only supports a subset of valid comparisons, see if we
10199 can convert an unsupported one into a supported one. */
10200 CANONICALIZE_COMPARISON (code
, op0
, op1
);
10209 /* Return 1 if we know that X, a comparison operation, is not operating
10210 on a floating-point value or is EQ or NE, meaning that we can safely
10214 reversible_comparison_p (x
)
10217 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
10219 || GET_CODE (x
) == NE
|| GET_CODE (x
) == EQ
)
10222 switch (GET_MODE_CLASS (GET_MODE (XEXP (x
, 0))))
10225 case MODE_PARTIAL_INT
:
10226 case MODE_COMPLEX_INT
:
10230 /* If the mode of the condition codes tells us that this is safe,
10231 we need look no further. */
10232 if (REVERSIBLE_CC_MODE (GET_MODE (XEXP (x
, 0))))
10235 /* Otherwise try and find where the condition codes were last set and
10237 x
= get_last_value (XEXP (x
, 0));
10238 return (x
&& GET_CODE (x
) == COMPARE
10239 && ! FLOAT_MODE_P (GET_MODE (XEXP (x
, 0))));
10246 /* Utility function for following routine. Called when X is part of a value
10247 being stored into reg_last_set_value. Sets reg_last_set_table_tick
10248 for each register mentioned. Similar to mention_regs in cse.c */
10251 update_table_tick (x
)
10254 register enum rtx_code code
= GET_CODE (x
);
10255 register char *fmt
= GET_RTX_FORMAT (code
);
10260 int regno
= REGNO (x
);
10261 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
10262 ? HARD_REGNO_NREGS (regno
, GET_MODE (x
)) : 1);
10264 for (i
= regno
; i
< endregno
; i
++)
10265 reg_last_set_table_tick
[i
] = label_tick
;
10270 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
10271 /* Note that we can't have an "E" in values stored; see
10272 get_last_value_validate. */
10274 update_table_tick (XEXP (x
, i
));
10277 /* Record that REG is set to VALUE in insn INSN. If VALUE is zero, we
10278 are saying that the register is clobbered and we no longer know its
10279 value. If INSN is zero, don't update reg_last_set; this is only permitted
10280 with VALUE also zero and is used to invalidate the register. */
10283 record_value_for_reg (reg
, insn
, value
)
10288 int regno
= REGNO (reg
);
10289 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
10290 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1);
10293 /* If VALUE contains REG and we have a previous value for REG, substitute
10294 the previous value. */
10295 if (value
&& insn
&& reg_overlap_mentioned_p (reg
, value
))
10299 /* Set things up so get_last_value is allowed to see anything set up to
10301 subst_low_cuid
= INSN_CUID (insn
);
10302 tem
= get_last_value (reg
);
10305 value
= replace_rtx (copy_rtx (value
), reg
, tem
);
10308 /* For each register modified, show we don't know its value, that
10309 we don't know about its bitwise content, that its value has been
10310 updated, and that we don't know the location of the death of the
10312 for (i
= regno
; i
< endregno
; i
++)
10315 reg_last_set
[i
] = insn
;
10316 reg_last_set_value
[i
] = 0;
10317 reg_last_set_mode
[i
] = 0;
10318 reg_last_set_nonzero_bits
[i
] = 0;
10319 reg_last_set_sign_bit_copies
[i
] = 0;
10320 reg_last_death
[i
] = 0;
10323 /* Mark registers that are being referenced in this value. */
10325 update_table_tick (value
);
10327 /* Now update the status of each register being set.
10328 If someone is using this register in this block, set this register
10329 to invalid since we will get confused between the two lives in this
10330 basic block. This makes using this register always invalid. In cse, we
10331 scan the table to invalidate all entries using this register, but this
10332 is too much work for us. */
10334 for (i
= regno
; i
< endregno
; i
++)
10336 reg_last_set_label
[i
] = label_tick
;
10337 if (value
&& reg_last_set_table_tick
[i
] == label_tick
)
10338 reg_last_set_invalid
[i
] = 1;
10340 reg_last_set_invalid
[i
] = 0;
10343 /* The value being assigned might refer to X (like in "x++;"). In that
10344 case, we must replace it with (clobber (const_int 0)) to prevent
10346 if (value
&& ! get_last_value_validate (&value
, insn
,
10347 reg_last_set_label
[regno
], 0))
10349 value
= copy_rtx (value
);
10350 if (! get_last_value_validate (&value
, insn
,
10351 reg_last_set_label
[regno
], 1))
10355 /* For the main register being modified, update the value, the mode, the
10356 nonzero bits, and the number of sign bit copies. */
10358 reg_last_set_value
[regno
] = value
;
10362 subst_low_cuid
= INSN_CUID (insn
);
10363 reg_last_set_mode
[regno
] = GET_MODE (reg
);
10364 reg_last_set_nonzero_bits
[regno
] = nonzero_bits (value
, GET_MODE (reg
));
10365 reg_last_set_sign_bit_copies
[regno
]
10366 = num_sign_bit_copies (value
, GET_MODE (reg
));
10370 /* Used for communication between the following two routines. */
10371 static rtx record_dead_insn
;
10373 /* Called via note_stores from record_dead_and_set_regs to handle one
10374 SET or CLOBBER in an insn. */
10377 record_dead_and_set_regs_1 (dest
, setter
)
10380 if (GET_CODE (dest
) == SUBREG
)
10381 dest
= SUBREG_REG (dest
);
10383 if (GET_CODE (dest
) == REG
)
10385 /* If we are setting the whole register, we know its value. Otherwise
10386 show that we don't know the value. We can handle SUBREG in
10388 if (GET_CODE (setter
) == SET
&& dest
== SET_DEST (setter
))
10389 record_value_for_reg (dest
, record_dead_insn
, SET_SRC (setter
));
10390 else if (GET_CODE (setter
) == SET
10391 && GET_CODE (SET_DEST (setter
)) == SUBREG
10392 && SUBREG_REG (SET_DEST (setter
)) == dest
10393 && GET_MODE_BITSIZE (GET_MODE (dest
)) <= BITS_PER_WORD
10394 && subreg_lowpart_p (SET_DEST (setter
)))
10395 record_value_for_reg (dest
, record_dead_insn
,
10396 gen_lowpart_for_combine (GET_MODE (dest
),
10397 SET_SRC (setter
)));
10399 record_value_for_reg (dest
, record_dead_insn
, NULL_RTX
);
10401 else if (GET_CODE (dest
) == MEM
10402 /* Ignore pushes, they clobber nothing. */
10403 && ! push_operand (dest
, GET_MODE (dest
)))
10404 mem_last_set
= INSN_CUID (record_dead_insn
);
10407 /* Update the records of when each REG was most recently set or killed
10408 for the things done by INSN. This is the last thing done in processing
10409 INSN in the combiner loop.
10411 We update reg_last_set, reg_last_set_value, reg_last_set_mode,
10412 reg_last_set_nonzero_bits, reg_last_set_sign_bit_copies, reg_last_death,
10413 and also the similar information mem_last_set (which insn most recently
10414 modified memory) and last_call_cuid (which insn was the most recent
10415 subroutine call). */
10418 record_dead_and_set_regs (insn
)
10424 for (link
= REG_NOTES (insn
); link
; link
= XEXP (link
, 1))
10426 if (REG_NOTE_KIND (link
) == REG_DEAD
10427 && GET_CODE (XEXP (link
, 0)) == REG
)
10429 int regno
= REGNO (XEXP (link
, 0));
10431 = regno
+ (regno
< FIRST_PSEUDO_REGISTER
10432 ? HARD_REGNO_NREGS (regno
, GET_MODE (XEXP (link
, 0)))
10435 for (i
= regno
; i
< endregno
; i
++)
10436 reg_last_death
[i
] = insn
;
10438 else if (REG_NOTE_KIND (link
) == REG_INC
)
10439 record_value_for_reg (XEXP (link
, 0), insn
, NULL_RTX
);
10442 if (GET_CODE (insn
) == CALL_INSN
)
10444 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
10445 if (call_used_regs
[i
])
10447 reg_last_set_value
[i
] = 0;
10448 reg_last_set_mode
[i
] = 0;
10449 reg_last_set_nonzero_bits
[i
] = 0;
10450 reg_last_set_sign_bit_copies
[i
] = 0;
10451 reg_last_death
[i
] = 0;
10454 last_call_cuid
= mem_last_set
= INSN_CUID (insn
);
10457 record_dead_insn
= insn
;
10458 note_stores (PATTERN (insn
), record_dead_and_set_regs_1
);
10461 /* Utility routine for the following function. Verify that all the registers
10462 mentioned in *LOC are valid when *LOC was part of a value set when
10463 label_tick == TICK. Return 0 if some are not.
10465 If REPLACE is non-zero, replace the invalid reference with
10466 (clobber (const_int 0)) and return 1. This replacement is useful because
10467 we often can get useful information about the form of a value (e.g., if
10468 it was produced by a shift that always produces -1 or 0) even though
10469 we don't know exactly what registers it was produced from. */
10472 get_last_value_validate (loc
, insn
, tick
, replace
)
10479 char *fmt
= GET_RTX_FORMAT (GET_CODE (x
));
10480 int len
= GET_RTX_LENGTH (GET_CODE (x
));
10483 if (GET_CODE (x
) == REG
)
10485 int regno
= REGNO (x
);
10486 int endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
10487 ? HARD_REGNO_NREGS (regno
, GET_MODE (x
)) : 1);
10490 for (j
= regno
; j
< endregno
; j
++)
10491 if (reg_last_set_invalid
[j
]
10492 /* If this is a pseudo-register that was only set once, it is
10494 || (! (regno
>= FIRST_PSEUDO_REGISTER
&& REG_N_SETS (regno
) == 1)
10495 && reg_last_set_label
[j
] > tick
))
10498 *loc
= gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
);
10504 /* If this is a memory reference, make sure that there were
10505 no stores after it that might have clobbered the value. We don't
10506 have alias info, so we assume any store invalidates it. */
10507 else if (GET_CODE (x
) == MEM
&& ! RTX_UNCHANGING_P (x
)
10508 && INSN_CUID (insn
) <= mem_last_set
)
10511 *loc
= gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
);
10515 for (i
= 0; i
< len
; i
++)
10517 && get_last_value_validate (&XEXP (x
, i
), insn
, tick
, replace
) == 0)
10518 /* Don't bother with these. They shouldn't occur anyway. */
10522 /* If we haven't found a reason for it to be invalid, it is valid. */
10526 /* Get the last value assigned to X, if known. Some registers
10527 in the value may be replaced with (clobber (const_int 0)) if their value
10528 is known longer known reliably. */
10537 /* If this is a non-paradoxical SUBREG, get the value of its operand and
10538 then convert it to the desired mode. If this is a paradoxical SUBREG,
10539 we cannot predict what values the "extra" bits might have. */
10540 if (GET_CODE (x
) == SUBREG
10541 && subreg_lowpart_p (x
)
10542 && (GET_MODE_SIZE (GET_MODE (x
))
10543 <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x
))))
10544 && (value
= get_last_value (SUBREG_REG (x
))) != 0)
10545 return gen_lowpart_for_combine (GET_MODE (x
), value
);
10547 if (GET_CODE (x
) != REG
)
10551 value
= reg_last_set_value
[regno
];
10553 /* If we don't have a value or if it isn't for this basic block,
10557 || (REG_N_SETS (regno
) != 1
10558 && reg_last_set_label
[regno
] != label_tick
))
10561 /* If the value was set in a later insn than the ones we are processing,
10562 we can't use it even if the register was only set once, but make a quick
10563 check to see if the previous insn set it to something. This is commonly
10564 the case when the same pseudo is used by repeated insns.
10566 This does not work if there exists an instruction which is temporarily
10567 not on the insn chain. */
10569 if (INSN_CUID (reg_last_set
[regno
]) >= subst_low_cuid
)
10573 /* We can not do anything useful in this case, because there is
10574 an instruction which is not on the insn chain. */
10575 if (subst_prev_insn
)
10578 /* Skip over USE insns. They are not useful here, and they may have
10579 been made by combine, in which case they do not have a INSN_CUID
10580 value. We can't use prev_real_insn, because that would incorrectly
10581 take us backwards across labels. Skip over BARRIERs also, since
10582 they could have been made by combine. If we see one, we must be
10583 optimizing dead code, so it doesn't matter what we do. */
10584 for (insn
= prev_nonnote_insn (subst_insn
);
10585 insn
&& ((GET_CODE (insn
) == INSN
10586 && GET_CODE (PATTERN (insn
)) == USE
)
10587 || GET_CODE (insn
) == BARRIER
10588 || INSN_CUID (insn
) >= subst_low_cuid
);
10589 insn
= prev_nonnote_insn (insn
))
10593 && (set
= single_set (insn
)) != 0
10594 && rtx_equal_p (SET_DEST (set
), x
))
10596 value
= SET_SRC (set
);
10598 /* Make sure that VALUE doesn't reference X. Replace any
10599 explicit references with a CLOBBER. If there are any remaining
10600 references (rare), don't use the value. */
10602 if (reg_mentioned_p (x
, value
))
10603 value
= replace_rtx (copy_rtx (value
), x
,
10604 gen_rtx (CLOBBER
, GET_MODE (x
), const0_rtx
));
10606 if (reg_overlap_mentioned_p (x
, value
))
10613 /* If the value has all its registers valid, return it. */
10614 if (get_last_value_validate (&value
, reg_last_set
[regno
],
10615 reg_last_set_label
[regno
], 0))
10618 /* Otherwise, make a copy and replace any invalid register with
10619 (clobber (const_int 0)). If that fails for some reason, return 0. */
10621 value
= copy_rtx (value
);
10622 if (get_last_value_validate (&value
, reg_last_set
[regno
],
10623 reg_last_set_label
[regno
], 1))
10629 /* Return nonzero if expression X refers to a REG or to memory
10630 that is set in an instruction more recent than FROM_CUID. */
10633 use_crosses_set_p (x
, from_cuid
)
10637 register char *fmt
;
10639 register enum rtx_code code
= GET_CODE (x
);
10643 register int regno
= REGNO (x
);
10644 int endreg
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
10645 ? HARD_REGNO_NREGS (regno
, GET_MODE (x
)) : 1);
10647 #ifdef PUSH_ROUNDING
10648 /* Don't allow uses of the stack pointer to be moved,
10649 because we don't know whether the move crosses a push insn. */
10650 if (regno
== STACK_POINTER_REGNUM
)
10653 for (;regno
< endreg
; regno
++)
10654 if (reg_last_set
[regno
]
10655 && INSN_CUID (reg_last_set
[regno
]) > from_cuid
)
10660 if (code
== MEM
&& mem_last_set
> from_cuid
)
10663 fmt
= GET_RTX_FORMAT (code
);
10665 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
10670 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
10671 if (use_crosses_set_p (XVECEXP (x
, i
, j
), from_cuid
))
10674 else if (fmt
[i
] == 'e'
10675 && use_crosses_set_p (XEXP (x
, i
), from_cuid
))
10681 /* Define three variables used for communication between the following
10684 static int reg_dead_regno
, reg_dead_endregno
;
10685 static int reg_dead_flag
;
10687 /* Function called via note_stores from reg_dead_at_p.
10689 If DEST is within [reg_dead_regno, reg_dead_endregno), set
10690 reg_dead_flag to 1 if X is a CLOBBER and to -1 it is a SET. */
10693 reg_dead_at_p_1 (dest
, x
)
10697 int regno
, endregno
;
10699 if (GET_CODE (dest
) != REG
)
10702 regno
= REGNO (dest
);
10703 endregno
= regno
+ (regno
< FIRST_PSEUDO_REGISTER
10704 ? HARD_REGNO_NREGS (regno
, GET_MODE (dest
)) : 1);
10706 if (reg_dead_endregno
> regno
&& reg_dead_regno
< endregno
)
10707 reg_dead_flag
= (GET_CODE (x
) == CLOBBER
) ? 1 : -1;
10710 /* Return non-zero if REG is known to be dead at INSN.
10712 We scan backwards from INSN. If we hit a REG_DEAD note or a CLOBBER
10713 referencing REG, it is dead. If we hit a SET referencing REG, it is
10714 live. Otherwise, see if it is live or dead at the start of the basic
10715 block we are in. Hard regs marked as being live in NEWPAT_USED_REGS
10716 must be assumed to be always live. */
10719 reg_dead_at_p (reg
, insn
)
10725 /* Set variables for reg_dead_at_p_1. */
10726 reg_dead_regno
= REGNO (reg
);
10727 reg_dead_endregno
= reg_dead_regno
+ (reg_dead_regno
< FIRST_PSEUDO_REGISTER
10728 ? HARD_REGNO_NREGS (reg_dead_regno
,
10734 /* Check that reg isn't mentioned in NEWPAT_USED_REGS. */
10735 if (reg_dead_regno
< FIRST_PSEUDO_REGISTER
)
10737 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
10738 if (TEST_HARD_REG_BIT (newpat_used_regs
, i
))
10742 /* Scan backwards until we find a REG_DEAD note, SET, CLOBBER, label, or
10743 beginning of function. */
10744 for (; insn
&& GET_CODE (insn
) != CODE_LABEL
&& GET_CODE (insn
) != BARRIER
;
10745 insn
= prev_nonnote_insn (insn
))
10747 note_stores (PATTERN (insn
), reg_dead_at_p_1
);
10749 return reg_dead_flag
== 1 ? 1 : 0;
10751 if (find_regno_note (insn
, REG_DEAD
, reg_dead_regno
))
10755 /* Get the basic block number that we were in. */
10760 for (block
= 0; block
< n_basic_blocks
; block
++)
10761 if (insn
== basic_block_head
[block
])
10764 if (block
== n_basic_blocks
)
10768 for (i
= reg_dead_regno
; i
< reg_dead_endregno
; i
++)
10769 if (REGNO_REG_SET_P (basic_block_live_at_start
[block
], i
))
10775 /* Note hard registers in X that are used. This code is similar to
10776 that in flow.c, but much simpler since we don't care about pseudos. */
10779 mark_used_regs_combine (x
)
10782 register RTX_CODE code
= GET_CODE (x
);
10783 register int regno
;
10795 case ADDR_DIFF_VEC
:
10798 /* CC0 must die in the insn after it is set, so we don't need to take
10799 special note of it here. */
10805 /* If we are clobbering a MEM, mark any hard registers inside the
10806 address as used. */
10807 if (GET_CODE (XEXP (x
, 0)) == MEM
)
10808 mark_used_regs_combine (XEXP (XEXP (x
, 0), 0));
10813 /* A hard reg in a wide mode may really be multiple registers.
10814 If so, mark all of them just like the first. */
10815 if (regno
< FIRST_PSEUDO_REGISTER
)
10817 /* None of this applies to the stack, frame or arg pointers */
10818 if (regno
== STACK_POINTER_REGNUM
10819 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
10820 || regno
== HARD_FRAME_POINTER_REGNUM
10822 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
10823 || (regno
== ARG_POINTER_REGNUM
&& fixed_regs
[regno
])
10825 || regno
== FRAME_POINTER_REGNUM
)
10828 i
= HARD_REGNO_NREGS (regno
, GET_MODE (x
));
10830 SET_HARD_REG_BIT (newpat_used_regs
, regno
+ i
);
10836 /* If setting a MEM, or a SUBREG of a MEM, then note any hard regs in
10838 register rtx testreg
= SET_DEST (x
);
10840 while (GET_CODE (testreg
) == SUBREG
10841 || GET_CODE (testreg
) == ZERO_EXTRACT
10842 || GET_CODE (testreg
) == SIGN_EXTRACT
10843 || GET_CODE (testreg
) == STRICT_LOW_PART
)
10844 testreg
= XEXP (testreg
, 0);
10846 if (GET_CODE (testreg
) == MEM
)
10847 mark_used_regs_combine (XEXP (testreg
, 0));
10849 mark_used_regs_combine (SET_SRC (x
));
10857 /* Recursively scan the operands of this expression. */
10860 register char *fmt
= GET_RTX_FORMAT (code
);
10862 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
10865 mark_used_regs_combine (XEXP (x
, i
));
10866 else if (fmt
[i
] == 'E')
10870 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
10871 mark_used_regs_combine (XVECEXP (x
, i
, j
));
10878 /* Remove register number REGNO from the dead registers list of INSN.
10880 Return the note used to record the death, if there was one. */
10883 remove_death (regno
, insn
)
10887 register rtx note
= find_regno_note (insn
, REG_DEAD
, regno
);
10891 REG_N_DEATHS (regno
)--;
10892 remove_note (insn
, note
);
10898 /* For each register (hardware or pseudo) used within expression X, if its
10899 death is in an instruction with cuid between FROM_CUID (inclusive) and
10900 TO_INSN (exclusive), put a REG_DEAD note for that register in the
10901 list headed by PNOTES.
10903 That said, don't move registers killed by maybe_kill_insn.
10905 This is done when X is being merged by combination into TO_INSN. These
10906 notes will then be distributed as needed. */
10909 move_deaths (x
, maybe_kill_insn
, from_cuid
, to_insn
, pnotes
)
10911 rtx maybe_kill_insn
;
10916 register char *fmt
;
10917 register int len
, i
;
10918 register enum rtx_code code
= GET_CODE (x
);
10922 register int regno
= REGNO (x
);
10923 register rtx where_dead
= reg_last_death
[regno
];
10924 register rtx before_dead
, after_dead
;
10926 /* Don't move the register if it gets killed in between from and to */
10927 if (maybe_kill_insn
&& reg_set_p (x
, maybe_kill_insn
)
10928 && !reg_referenced_p (x
, maybe_kill_insn
))
10931 /* WHERE_DEAD could be a USE insn made by combine, so first we
10932 make sure that we have insns with valid INSN_CUID values. */
10933 before_dead
= where_dead
;
10934 while (before_dead
&& INSN_UID (before_dead
) > max_uid_cuid
)
10935 before_dead
= PREV_INSN (before_dead
);
10936 after_dead
= where_dead
;
10937 while (after_dead
&& INSN_UID (after_dead
) > max_uid_cuid
)
10938 after_dead
= NEXT_INSN (after_dead
);
10940 if (before_dead
&& after_dead
10941 && INSN_CUID (before_dead
) >= from_cuid
10942 && (INSN_CUID (after_dead
) < INSN_CUID (to_insn
)
10943 || (where_dead
!= after_dead
10944 && INSN_CUID (after_dead
) == INSN_CUID (to_insn
))))
10946 rtx note
= remove_death (regno
, where_dead
);
10948 /* It is possible for the call above to return 0. This can occur
10949 when reg_last_death points to I2 or I1 that we combined with.
10950 In that case make a new note.
10952 We must also check for the case where X is a hard register
10953 and NOTE is a death note for a range of hard registers
10954 including X. In that case, we must put REG_DEAD notes for
10955 the remaining registers in place of NOTE. */
10957 if (note
!= 0 && regno
< FIRST_PSEUDO_REGISTER
10958 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
10959 > GET_MODE_SIZE (GET_MODE (x
))))
10961 int deadregno
= REGNO (XEXP (note
, 0));
10963 = (deadregno
+ HARD_REGNO_NREGS (deadregno
,
10964 GET_MODE (XEXP (note
, 0))));
10965 int ourend
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (x
));
10968 for (i
= deadregno
; i
< deadend
; i
++)
10969 if (i
< regno
|| i
>= ourend
)
10970 REG_NOTES (where_dead
)
10971 = gen_rtx (EXPR_LIST
, REG_DEAD
,
10972 gen_rtx (REG
, reg_raw_mode
[i
], i
),
10973 REG_NOTES (where_dead
));
10975 /* If we didn't find any note, or if we found a REG_DEAD note that
10976 covers only part of the given reg, and we have a multi-reg hard
10977 register, then to be safe we must check for REG_DEAD notes
10978 for each register other than the first. They could have
10979 their own REG_DEAD notes lying around. */
10980 else if ((note
== 0
10982 && (GET_MODE_SIZE (GET_MODE (XEXP (note
, 0)))
10983 < GET_MODE_SIZE (GET_MODE (x
)))))
10984 && regno
< FIRST_PSEUDO_REGISTER
10985 && HARD_REGNO_NREGS (regno
, GET_MODE (x
)) > 1)
10987 int ourend
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (x
));
10992 offset
= HARD_REGNO_NREGS (regno
, GET_MODE (XEXP (note
, 0)));
10996 for (i
= regno
+ offset
; i
< ourend
; i
++)
10997 move_deaths (gen_rtx (REG
, reg_raw_mode
[i
], i
),
10998 maybe_kill_insn
, from_cuid
, to_insn
, &oldnotes
);
11001 if (note
!= 0 && GET_MODE (XEXP (note
, 0)) == GET_MODE (x
))
11003 XEXP (note
, 1) = *pnotes
;
11007 *pnotes
= gen_rtx (EXPR_LIST
, REG_DEAD
, x
, *pnotes
);
11009 REG_N_DEATHS (regno
)++;
11015 else if (GET_CODE (x
) == SET
)
11017 rtx dest
= SET_DEST (x
);
11019 move_deaths (SET_SRC (x
), maybe_kill_insn
, from_cuid
, to_insn
, pnotes
);
11021 /* In the case of a ZERO_EXTRACT, a STRICT_LOW_PART, or a SUBREG
11022 that accesses one word of a multi-word item, some
11023 piece of everything register in the expression is used by
11024 this insn, so remove any old death. */
11026 if (GET_CODE (dest
) == ZERO_EXTRACT
11027 || GET_CODE (dest
) == STRICT_LOW_PART
11028 || (GET_CODE (dest
) == SUBREG
11029 && (((GET_MODE_SIZE (GET_MODE (dest
))
11030 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
)
11031 == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest
)))
11032 + UNITS_PER_WORD
- 1) / UNITS_PER_WORD
))))
11034 move_deaths (dest
, maybe_kill_insn
, from_cuid
, to_insn
, pnotes
);
11038 /* If this is some other SUBREG, we know it replaces the entire
11039 value, so use that as the destination. */
11040 if (GET_CODE (dest
) == SUBREG
)
11041 dest
= SUBREG_REG (dest
);
11043 /* If this is a MEM, adjust deaths of anything used in the address.
11044 For a REG (the only other possibility), the entire value is
11045 being replaced so the old value is not used in this insn. */
11047 if (GET_CODE (dest
) == MEM
)
11048 move_deaths (XEXP (dest
, 0), maybe_kill_insn
, from_cuid
,
11053 else if (GET_CODE (x
) == CLOBBER
)
11056 len
= GET_RTX_LENGTH (code
);
11057 fmt
= GET_RTX_FORMAT (code
);
11059 for (i
= 0; i
< len
; i
++)
11064 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
11065 move_deaths (XVECEXP (x
, i
, j
), maybe_kill_insn
, from_cuid
,
11068 else if (fmt
[i
] == 'e')
11069 move_deaths (XEXP (x
, i
), maybe_kill_insn
, from_cuid
, to_insn
, pnotes
);
11073 /* Return 1 if X is the target of a bit-field assignment in BODY, the
11074 pattern of an insn. X must be a REG. */
11077 reg_bitfield_target_p (x
, body
)
11083 if (GET_CODE (body
) == SET
)
11085 rtx dest
= SET_DEST (body
);
11087 int regno
, tregno
, endregno
, endtregno
;
11089 if (GET_CODE (dest
) == ZERO_EXTRACT
)
11090 target
= XEXP (dest
, 0);
11091 else if (GET_CODE (dest
) == STRICT_LOW_PART
)
11092 target
= SUBREG_REG (XEXP (dest
, 0));
11096 if (GET_CODE (target
) == SUBREG
)
11097 target
= SUBREG_REG (target
);
11099 if (GET_CODE (target
) != REG
)
11102 tregno
= REGNO (target
), regno
= REGNO (x
);
11103 if (tregno
>= FIRST_PSEUDO_REGISTER
|| regno
>= FIRST_PSEUDO_REGISTER
)
11104 return target
== x
;
11106 endtregno
= tregno
+ HARD_REGNO_NREGS (tregno
, GET_MODE (target
));
11107 endregno
= regno
+ HARD_REGNO_NREGS (regno
, GET_MODE (x
));
11109 return endregno
> tregno
&& regno
< endtregno
;
11112 else if (GET_CODE (body
) == PARALLEL
)
11113 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; i
--)
11114 if (reg_bitfield_target_p (x
, XVECEXP (body
, 0, i
)))
11120 /* Given a chain of REG_NOTES originally from FROM_INSN, try to place them
11121 as appropriate. I3 and I2 are the insns resulting from the combination
11122 insns including FROM (I2 may be zero).
11124 ELIM_I2 and ELIM_I1 are either zero or registers that we know will
11125 not need REG_DEAD notes because they are being substituted for. This
11126 saves searching in the most common cases.
11128 Each note in the list is either ignored or placed on some insns, depending
11129 on the type of note. */
11132 distribute_notes (notes
, from_insn
, i3
, i2
, elim_i2
, elim_i1
)
11136 rtx elim_i2
, elim_i1
;
11138 rtx note
, next_note
;
11141 for (note
= notes
; note
; note
= next_note
)
11143 rtx place
= 0, place2
= 0;
11145 /* If this NOTE references a pseudo register, ensure it references
11146 the latest copy of that register. */
11147 if (XEXP (note
, 0) && GET_CODE (XEXP (note
, 0)) == REG
11148 && REGNO (XEXP (note
, 0)) >= FIRST_PSEUDO_REGISTER
)
11149 XEXP (note
, 0) = regno_reg_rtx
[REGNO (XEXP (note
, 0))];
11151 next_note
= XEXP (note
, 1);
11152 switch (REG_NOTE_KIND (note
))
11155 case REG_EXEC_COUNT
:
11156 /* Doesn't matter much where we put this, as long as it's somewhere.
11157 It is preferable to keep these notes on branches, which is most
11158 likely to be i3. */
11163 /* Any clobbers for i3 may still exist, and so we must process
11164 REG_UNUSED notes from that insn.
11166 Any clobbers from i2 or i1 can only exist if they were added by
11167 recog_for_combine. In that case, recog_for_combine created the
11168 necessary REG_UNUSED notes. Trying to keep any original
11169 REG_UNUSED notes from these insns can cause incorrect output
11170 if it is for the same register as the original i3 dest.
11171 In that case, we will notice that the register is set in i3,
11172 and then add a REG_UNUSED note for the destination of i3, which
11173 is wrong. However, it is possible to have REG_UNUSED notes from
11174 i2 or i1 for register which were both used and clobbered, so
11175 we keep notes from i2 or i1 if they will turn into REG_DEAD
11178 /* If this register is set or clobbered in I3, put the note there
11179 unless there is one already. */
11180 if (reg_set_p (XEXP (note
, 0), PATTERN (i3
)))
11182 if (from_insn
!= i3
)
11185 if (! (GET_CODE (XEXP (note
, 0)) == REG
11186 ? find_regno_note (i3
, REG_UNUSED
, REGNO (XEXP (note
, 0)))
11187 : find_reg_note (i3
, REG_UNUSED
, XEXP (note
, 0))))
11190 /* Otherwise, if this register is used by I3, then this register
11191 now dies here, so we must put a REG_DEAD note here unless there
11193 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
))
11194 && ! (GET_CODE (XEXP (note
, 0)) == REG
11195 ? find_regno_note (i3
, REG_DEAD
, REGNO (XEXP (note
, 0)))
11196 : find_reg_note (i3
, REG_DEAD
, XEXP (note
, 0))))
11198 PUT_REG_NOTE_KIND (note
, REG_DEAD
);
11207 /* These notes say something about results of an insn. We can
11208 only support them if they used to be on I3 in which case they
11209 remain on I3. Otherwise they are ignored.
11211 If the note refers to an expression that is not a constant, we
11212 must also ignore the note since we cannot tell whether the
11213 equivalence is still true. It might be possible to do
11214 slightly better than this (we only have a problem if I2DEST
11215 or I1DEST is present in the expression), but it doesn't
11216 seem worth the trouble. */
11218 if (from_insn
== i3
11219 && (XEXP (note
, 0) == 0 || CONSTANT_P (XEXP (note
, 0))))
11224 case REG_NO_CONFLICT
:
11226 /* These notes say something about how a register is used. They must
11227 be present on any use of the register in I2 or I3. */
11228 if (reg_mentioned_p (XEXP (note
, 0), PATTERN (i3
)))
11231 if (i2
&& reg_mentioned_p (XEXP (note
, 0), PATTERN (i2
)))
11241 /* It is too much trouble to try to see if this note is still
11242 correct in all situations. It is better to simply delete it. */
11246 /* If the insn previously containing this note still exists,
11247 put it back where it was. Otherwise move it to the previous
11248 insn. Adjust the corresponding REG_LIBCALL note. */
11249 if (GET_CODE (from_insn
) != NOTE
)
11253 tem
= find_reg_note (XEXP (note
, 0), REG_LIBCALL
, NULL_RTX
);
11254 place
= prev_real_insn (from_insn
);
11256 XEXP (tem
, 0) = place
;
11261 /* This is handled similarly to REG_RETVAL. */
11262 if (GET_CODE (from_insn
) != NOTE
)
11266 tem
= find_reg_note (XEXP (note
, 0), REG_RETVAL
, NULL_RTX
);
11267 place
= next_real_insn (from_insn
);
11269 XEXP (tem
, 0) = place
;
11274 /* If the register is used as an input in I3, it dies there.
11275 Similarly for I2, if it is non-zero and adjacent to I3.
11277 If the register is not used as an input in either I3 or I2
11278 and it is not one of the registers we were supposed to eliminate,
11279 there are two possibilities. We might have a non-adjacent I2
11280 or we might have somehow eliminated an additional register
11281 from a computation. For example, we might have had A & B where
11282 we discover that B will always be zero. In this case we will
11283 eliminate the reference to A.
11285 In both cases, we must search to see if we can find a previous
11286 use of A and put the death note there. */
11289 && GET_CODE (from_insn
) == CALL_INSN
11290 && find_reg_fusage (from_insn
, USE
, XEXP (note
, 0)))
11292 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (i3
)))
11294 else if (i2
!= 0 && next_nonnote_insn (i2
) == i3
11295 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
11298 if (XEXP (note
, 0) == elim_i2
|| XEXP (note
, 0) == elim_i1
)
11301 /* If the register is used in both I2 and I3 and it dies in I3,
11302 we might have added another reference to it. If reg_n_refs
11303 was 2, bump it to 3. This has to be correct since the
11304 register must have been set somewhere. The reason this is
11305 done is because local-alloc.c treats 2 references as a
11308 if (place
== i3
&& i2
!= 0 && GET_CODE (XEXP (note
, 0)) == REG
11309 && REG_N_REFS (REGNO (XEXP (note
, 0)))== 2
11310 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
11311 REG_N_REFS (REGNO (XEXP (note
, 0))) = 3;
11315 for (tem
= prev_nonnote_insn (i3
);
11317 && (GET_CODE (tem
) == INSN
|| GET_CODE (tem
) == CALL_INSN
);
11318 tem
= prev_nonnote_insn (tem
))
11320 /* If the register is being set at TEM, see if that is all
11321 TEM is doing. If so, delete TEM. Otherwise, make this
11322 into a REG_UNUSED note instead. */
11323 if (reg_set_p (XEXP (note
, 0), PATTERN (tem
)))
11325 rtx set
= single_set (tem
);
11327 /* Verify that it was the set, and not a clobber that
11328 modified the register. */
11330 if (set
!= 0 && ! side_effects_p (SET_SRC (set
))
11331 && (rtx_equal_p (XEXP (note
, 0), SET_DEST (set
))
11332 || (GET_CODE (SET_DEST (set
)) == SUBREG
11333 && rtx_equal_p (XEXP (note
, 0),
11334 XEXP (SET_DEST (set
), 0)))))
11336 /* Move the notes and links of TEM elsewhere.
11337 This might delete other dead insns recursively.
11338 First set the pattern to something that won't use
11341 PATTERN (tem
) = pc_rtx
;
11343 distribute_notes (REG_NOTES (tem
), tem
, tem
,
11344 NULL_RTX
, NULL_RTX
, NULL_RTX
);
11345 distribute_links (LOG_LINKS (tem
));
11347 PUT_CODE (tem
, NOTE
);
11348 NOTE_LINE_NUMBER (tem
) = NOTE_INSN_DELETED
;
11349 NOTE_SOURCE_FILE (tem
) = 0;
11353 PUT_REG_NOTE_KIND (note
, REG_UNUSED
);
11355 /* If there isn't already a REG_UNUSED note, put one
11357 if (! find_regno_note (tem
, REG_UNUSED
,
11358 REGNO (XEXP (note
, 0))))
11363 else if (reg_referenced_p (XEXP (note
, 0), PATTERN (tem
))
11364 || (GET_CODE (tem
) == CALL_INSN
11365 && find_reg_fusage (tem
, USE
, XEXP (note
, 0))))
11369 /* If we are doing a 3->2 combination, and we have a
11370 register which formerly died in i3 and was not used
11371 by i2, which now no longer dies in i3 and is used in
11372 i2 but does not die in i2, and place is between i2
11373 and i3, then we may need to move a link from place to
11375 if (i2
&& INSN_UID (place
) <= max_uid_cuid
11376 && INSN_CUID (place
) > INSN_CUID (i2
)
11377 && from_insn
&& INSN_CUID (from_insn
) > INSN_CUID (i2
)
11378 && reg_referenced_p (XEXP (note
, 0), PATTERN (i2
)))
11380 rtx links
= LOG_LINKS (place
);
11381 LOG_LINKS (place
) = 0;
11382 distribute_links (links
);
11388 /* If we haven't found an insn for the death note and it
11389 is still a REG_DEAD note, but we have hit a CODE_LABEL,
11390 insert a USE insn for the register at that label and
11391 put the death node there. This prevents problems with
11392 call-state tracking in caller-save.c. */
11393 if (REG_NOTE_KIND (note
) == REG_DEAD
&& place
== 0 && tem
!= 0)
11396 = emit_insn_after (gen_rtx (USE
, VOIDmode
, XEXP (note
, 0)),
11399 /* If this insn was emitted between blocks, then update
11400 basic_block_head of the current block to include it. */
11401 if (basic_block_end
[this_basic_block
- 1] == tem
)
11402 basic_block_head
[this_basic_block
] = place
;
11406 /* If the register is set or already dead at PLACE, we needn't do
11407 anything with this note if it is still a REG_DEAD note.
11409 Note that we cannot use just `dead_or_set_p' here since we can
11410 convert an assignment to a register into a bit-field assignment.
11411 Therefore, we must also omit the note if the register is the
11412 target of a bitfield assignment. */
11414 if (place
&& REG_NOTE_KIND (note
) == REG_DEAD
)
11416 int regno
= REGNO (XEXP (note
, 0));
11418 if (dead_or_set_p (place
, XEXP (note
, 0))
11419 || reg_bitfield_target_p (XEXP (note
, 0), PATTERN (place
)))
11421 /* Unless the register previously died in PLACE, clear
11422 reg_last_death. [I no longer understand why this is
11424 if (reg_last_death
[regno
] != place
)
11425 reg_last_death
[regno
] = 0;
11429 reg_last_death
[regno
] = place
;
11431 /* If this is a death note for a hard reg that is occupying
11432 multiple registers, ensure that we are still using all
11433 parts of the object. If we find a piece of the object
11434 that is unused, we must add a USE for that piece before
11435 PLACE and put the appropriate REG_DEAD note on it.
11437 An alternative would be to put a REG_UNUSED for the pieces
11438 on the insn that set the register, but that can't be done if
11439 it is not in the same block. It is simpler, though less
11440 efficient, to add the USE insns. */
11442 if (place
&& regno
< FIRST_PSEUDO_REGISTER
11443 && HARD_REGNO_NREGS (regno
, GET_MODE (XEXP (note
, 0))) > 1)
11446 = regno
+ HARD_REGNO_NREGS (regno
,
11447 GET_MODE (XEXP (note
, 0)));
11451 for (i
= regno
; i
< endregno
; i
++)
11452 if (! refers_to_regno_p (i
, i
+ 1, PATTERN (place
), 0)
11453 && ! find_regno_fusage (place
, USE
, i
))
11455 rtx piece
= gen_rtx (REG
, reg_raw_mode
[i
], i
);
11458 /* See if we already placed a USE note for this
11459 register in front of PLACE. */
11461 GET_CODE (PREV_INSN (p
)) == INSN
11462 && GET_CODE (PATTERN (PREV_INSN (p
))) == USE
;
11464 if (rtx_equal_p (piece
,
11465 XEXP (PATTERN (PREV_INSN (p
)), 0)))
11474 = emit_insn_before (gen_rtx (USE
, VOIDmode
,
11477 REG_NOTES (use_insn
)
11478 = gen_rtx (EXPR_LIST
, REG_DEAD
, piece
,
11479 REG_NOTES (use_insn
));
11485 /* Check for the case where the register dying partially
11486 overlaps the register set by this insn. */
11488 for (i
= regno
; i
< endregno
; i
++)
11489 if (dead_or_set_regno_p (place
, i
))
11497 /* Put only REG_DEAD notes for pieces that are
11498 still used and that are not already dead or set. */
11500 for (i
= regno
; i
< endregno
; i
++)
11502 rtx piece
= gen_rtx (REG
, reg_raw_mode
[i
], i
);
11504 if ((reg_referenced_p (piece
, PATTERN (place
))
11505 || (GET_CODE (place
) == CALL_INSN
11506 && find_reg_fusage (place
, USE
, piece
)))
11507 && ! dead_or_set_p (place
, piece
)
11508 && ! reg_bitfield_target_p (piece
,
11510 REG_NOTES (place
) = gen_rtx (EXPR_LIST
, REG_DEAD
,
11512 REG_NOTES (place
));
11522 /* Any other notes should not be present at this point in the
11529 XEXP (note
, 1) = REG_NOTES (place
);
11530 REG_NOTES (place
) = note
;
11532 else if ((REG_NOTE_KIND (note
) == REG_DEAD
11533 || REG_NOTE_KIND (note
) == REG_UNUSED
)
11534 && GET_CODE (XEXP (note
, 0)) == REG
)
11535 REG_N_DEATHS (REGNO (XEXP (note
, 0)))--;
11539 if ((REG_NOTE_KIND (note
) == REG_DEAD
11540 || REG_NOTE_KIND (note
) == REG_UNUSED
)
11541 && GET_CODE (XEXP (note
, 0)) == REG
)
11542 REG_N_DEATHS (REGNO (XEXP (note
, 0)))++;
11544 REG_NOTES (place2
) = gen_rtx (GET_CODE (note
), REG_NOTE_KIND (note
),
11545 XEXP (note
, 0), REG_NOTES (place2
));
11550 /* Similarly to above, distribute the LOG_LINKS that used to be present on
11551 I3, I2, and I1 to new locations. This is also called in one case to
11552 add a link pointing at I3 when I3's destination is changed. */
11555 distribute_links (links
)
11558 rtx link
, next_link
;
11560 for (link
= links
; link
; link
= next_link
)
11566 next_link
= XEXP (link
, 1);
11568 /* If the insn that this link points to is a NOTE or isn't a single
11569 set, ignore it. In the latter case, it isn't clear what we
11570 can do other than ignore the link, since we can't tell which
11571 register it was for. Such links wouldn't be used by combine
11574 It is not possible for the destination of the target of the link to
11575 have been changed by combine. The only potential of this is if we
11576 replace I3, I2, and I1 by I3 and I2. But in that case the
11577 destination of I2 also remains unchanged. */
11579 if (GET_CODE (XEXP (link
, 0)) == NOTE
11580 || (set
= single_set (XEXP (link
, 0))) == 0)
11583 reg
= SET_DEST (set
);
11584 while (GET_CODE (reg
) == SUBREG
|| GET_CODE (reg
) == ZERO_EXTRACT
11585 || GET_CODE (reg
) == SIGN_EXTRACT
11586 || GET_CODE (reg
) == STRICT_LOW_PART
)
11587 reg
= XEXP (reg
, 0);
11589 /* A LOG_LINK is defined as being placed on the first insn that uses
11590 a register and points to the insn that sets the register. Start
11591 searching at the next insn after the target of the link and stop
11592 when we reach a set of the register or the end of the basic block.
11594 Note that this correctly handles the link that used to point from
11595 I3 to I2. Also note that not much searching is typically done here
11596 since most links don't point very far away. */
11598 for (insn
= NEXT_INSN (XEXP (link
, 0));
11599 (insn
&& (this_basic_block
== n_basic_blocks
- 1
11600 || basic_block_head
[this_basic_block
+ 1] != insn
));
11601 insn
= NEXT_INSN (insn
))
11602 if (GET_RTX_CLASS (GET_CODE (insn
)) == 'i'
11603 && reg_overlap_mentioned_p (reg
, PATTERN (insn
)))
11605 if (reg_referenced_p (reg
, PATTERN (insn
)))
11609 else if (GET_CODE (insn
) == CALL_INSN
11610 && find_reg_fusage (insn
, USE
, reg
))
11616 /* If we found a place to put the link, place it there unless there
11617 is already a link to the same insn as LINK at that point. */
11623 for (link2
= LOG_LINKS (place
); link2
; link2
= XEXP (link2
, 1))
11624 if (XEXP (link2
, 0) == XEXP (link
, 0))
11629 XEXP (link
, 1) = LOG_LINKS (place
);
11630 LOG_LINKS (place
) = link
;
11632 /* Set added_links_insn to the earliest insn we added a
11634 if (added_links_insn
== 0
11635 || INSN_CUID (added_links_insn
) > INSN_CUID (place
))
11636 added_links_insn
= place
;
11642 /* Compute INSN_CUID for INSN, which is an insn made by combine. */
11648 while (insn
!= 0 && INSN_UID (insn
) > max_uid_cuid
11649 && GET_CODE (insn
) == INSN
&& GET_CODE (PATTERN (insn
)) == USE
)
11650 insn
= NEXT_INSN (insn
);
11652 if (INSN_UID (insn
) > max_uid_cuid
)
11655 return INSN_CUID (insn
);
11659 dump_combine_stats (file
)
11664 ";; Combiner statistics: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n\n",
11665 combine_attempts
, combine_merges
, combine_extras
, combine_successes
);
11669 dump_combine_total_stats (file
)
11674 "\n;; Combiner totals: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n",
11675 total_attempts
, total_merges
, total_extras
, total_successes
);