]>
Commit | Line | Data |
---|---|---|
6d716ca8 RS |
1 | /* Fold a constant sub-tree into a single node for C-compiler |
2 | Copyright (C) 1987, 1988, 1992 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU CC. | |
5 | ||
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) | |
9 | any later version. | |
10 | ||
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. | |
15 | ||
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, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /*@@ Fix lossage on folding division of big integers. */ | |
21 | ||
22 | /*@@ This file should be rewritten to use an arbitary precision | |
23 | @@ representation for "struct tree_int_cst" and "struct tree_real_cst". | |
24 | @@ Perhaps the routines could also be used for bc/dc, and made a lib. | |
25 | @@ The routines that translate from the ap rep should | |
26 | @@ warn if precision et. al. is lost. | |
27 | @@ This would also make life easier when this technology is used | |
28 | @@ for cross-compilers. */ | |
29 | ||
30 | ||
31 | /* The entry points in this file are fold, size_int and size_binop. | |
32 | ||
33 | fold takes a tree as argument and returns a simplified tree. | |
34 | ||
35 | size_binop takes a tree code for an arithmetic operation | |
36 | and two operands that are trees, and produces a tree for the | |
37 | result, assuming the type comes from `sizetype'. | |
38 | ||
39 | size_int takes an integer value, and creates a tree constant | |
40 | with type from `sizetype'. */ | |
41 | ||
42 | #include <stdio.h> | |
43 | #include <setjmp.h> | |
44 | #include "config.h" | |
45 | #include "flags.h" | |
46 | #include "tree.h" | |
47 | ||
48 | void lshift_double (); | |
49 | void rshift_double (); | |
50 | void lrotate_double (); | |
51 | void rrotate_double (); | |
52 | static tree const_binop (); | |
53 | \f | |
54 | /* To do constant folding on INTEGER_CST nodes requires 64-bit arithmetic. | |
55 | We do that by representing the 64-bit integer as 8 shorts, | |
56 | with only 8 bits stored in each short, as a positive number. */ | |
57 | ||
58 | /* Unpack a 64-bit integer into 8 shorts. | |
59 | LOW and HI are the integer, as two `int' pieces. | |
60 | SHORTS points to the array of shorts. */ | |
61 | ||
62 | static void | |
63 | encode (shorts, low, hi) | |
64 | short *shorts; | |
65 | int low, hi; | |
66 | { | |
67 | shorts[0] = low & 0xff; | |
68 | shorts[1] = (low >> 8) & 0xff; | |
69 | shorts[2] = (low >> 16) & 0xff; | |
70 | shorts[3] = (low >> 24) & 0xff; | |
71 | shorts[4] = hi & 0xff; | |
72 | shorts[5] = (hi >> 8) & 0xff; | |
73 | shorts[6] = (hi >> 16) & 0xff; | |
74 | shorts[7] = (hi >> 24) & 0xff; | |
75 | } | |
76 | ||
77 | /* Pack an array of 8 shorts into a 64-bit integer. | |
78 | SHORTS points to the array of shorts. | |
79 | The integer is stored into *LOW and *HI as two `int' pieces. */ | |
80 | ||
81 | static void | |
82 | decode (shorts, low, hi) | |
83 | short *shorts; | |
84 | int *low, *hi; | |
85 | { | |
86 | /* The casts in the following statement should not be | |
87 | needed, but they get around bugs in some C compilers. */ | |
88 | *low = (((long)shorts[3] << 24) | ((long)shorts[2] << 16) | |
89 | | ((long)shorts[1] << 8) | (long)shorts[0]); | |
90 | *hi = (((long)shorts[7] << 24) | ((long)shorts[6] << 16) | |
91 | | ((long)shorts[5] << 8) | (long)shorts[4]); | |
92 | } | |
93 | \f | |
94 | /* Make the integer constant T valid for its type | |
95 | by setting to 0 or 1 all the bits in the constant | |
96 | that don't belong in the type. */ | |
97 | ||
98 | static void | |
99 | force_fit_type (t) | |
100 | tree t; | |
101 | { | |
102 | register int prec = TYPE_PRECISION (TREE_TYPE (t)); | |
103 | ||
104 | if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE) | |
105 | prec = POINTER_SIZE; | |
106 | ||
107 | /* First clear all bits that are beyond the type's precision. */ | |
108 | ||
109 | if (prec == 2 * HOST_BITS_PER_INT) | |
110 | ; | |
111 | else if (prec > HOST_BITS_PER_INT) | |
112 | { | |
113 | TREE_INT_CST_HIGH (t) | |
114 | &= ~((-1) << (prec - HOST_BITS_PER_INT)); | |
115 | } | |
116 | else | |
117 | { | |
118 | TREE_INT_CST_HIGH (t) = 0; | |
119 | if (prec < HOST_BITS_PER_INT) | |
120 | TREE_INT_CST_LOW (t) | |
121 | &= ~((-1) << prec); | |
122 | } | |
123 | ||
124 | /* If it's a signed type and value's sign bit is set, extend the sign. */ | |
125 | ||
126 | if (! TREE_UNSIGNED (TREE_TYPE (t)) | |
127 | && prec != 2 * HOST_BITS_PER_INT | |
128 | && (prec > HOST_BITS_PER_INT | |
129 | ? TREE_INT_CST_HIGH (t) & (1 << (prec - HOST_BITS_PER_INT - 1)) | |
130 | : TREE_INT_CST_LOW (t) & (1 << (prec - 1)))) | |
131 | { | |
132 | /* Value is negative: | |
133 | set to 1 all the bits that are outside this type's precision. */ | |
134 | if (prec > HOST_BITS_PER_INT) | |
135 | { | |
136 | TREE_INT_CST_HIGH (t) | |
137 | |= ((-1) << (prec - HOST_BITS_PER_INT)); | |
138 | } | |
139 | else | |
140 | { | |
141 | TREE_INT_CST_HIGH (t) = -1; | |
142 | if (prec < HOST_BITS_PER_INT) | |
143 | TREE_INT_CST_LOW (t) | |
144 | |= ((-1) << prec); | |
145 | } | |
146 | } | |
147 | } | |
148 | \f | |
149 | /* Add two 64-bit integers with 64-bit result. | |
150 | Each argument is given as two `int' pieces. | |
151 | One argument is L1 and H1; the other, L2 and H2. | |
152 | The value is stored as two `int' pieces in *LV and *HV. | |
153 | We use the 8-shorts representation internally. */ | |
154 | ||
155 | void | |
156 | add_double (l1, h1, l2, h2, lv, hv) | |
157 | int l1, h1, l2, h2; | |
158 | int *lv, *hv; | |
159 | { | |
160 | short arg1[8]; | |
161 | short arg2[8]; | |
162 | register int carry = 0; | |
163 | register int i; | |
164 | ||
165 | encode (arg1, l1, h1); | |
166 | encode (arg2, l2, h2); | |
167 | ||
168 | for (i = 0; i < 8; i++) | |
169 | { | |
170 | carry += arg1[i] + arg2[i]; | |
171 | arg1[i] = carry & 0xff; | |
172 | carry >>= 8; | |
173 | } | |
174 | ||
175 | decode (arg1, lv, hv); | |
176 | } | |
177 | ||
178 | /* Negate a 64-bit integers with 64-bit result. | |
179 | The argument is given as two `int' pieces in L1 and H1. | |
180 | The value is stored as two `int' pieces in *LV and *HV. | |
181 | We use the 8-shorts representation internally. */ | |
182 | ||
183 | void | |
184 | neg_double (l1, h1, lv, hv) | |
185 | int l1, h1; | |
186 | int *lv, *hv; | |
187 | { | |
188 | if (l1 == 0) | |
189 | { | |
190 | *lv = 0; | |
191 | *hv = - h1; | |
192 | } | |
193 | else | |
194 | { | |
195 | *lv = - l1; | |
196 | *hv = ~ h1; | |
197 | } | |
198 | } | |
199 | \f | |
200 | /* Multiply two 64-bit integers with 64-bit result. | |
201 | Each argument is given as two `int' pieces. | |
202 | One argument is L1 and H1; the other, L2 and H2. | |
203 | The value is stored as two `int' pieces in *LV and *HV. | |
204 | We use the 8-shorts representation internally. */ | |
205 | ||
206 | void | |
207 | mul_double (l1, h1, l2, h2, lv, hv) | |
208 | int l1, h1, l2, h2; | |
209 | int *lv, *hv; | |
210 | { | |
211 | short arg1[8]; | |
212 | short arg2[8]; | |
213 | short prod[16]; | |
214 | register int carry = 0; | |
215 | register int i, j, k; | |
216 | ||
217 | /* These two cases are used extensively, arising from pointer | |
218 | combinations. */ | |
219 | if (h2 == 0) | |
220 | { | |
221 | if (l2 == 2) | |
222 | { | |
223 | unsigned temp = l1 + l1; | |
224 | *hv = h1 * 2 + (temp < l1); | |
225 | *lv = temp; | |
226 | return; | |
227 | } | |
228 | if (l2 == 4) | |
229 | { | |
230 | unsigned temp = l1 + l1; | |
231 | h1 = h1 * 4 + ((temp < l1) << 1); | |
232 | l1 = temp; | |
233 | temp += temp; | |
234 | h1 += (temp < l1); | |
235 | *lv = temp; | |
236 | *hv = h1; | |
237 | return; | |
238 | } | |
239 | if (l2 == 8) | |
240 | { | |
241 | unsigned temp = l1 + l1; | |
242 | h1 = h1 * 8 + ((temp < l1) << 2); | |
243 | l1 = temp; | |
244 | temp += temp; | |
245 | h1 += (temp < l1) << 1; | |
246 | l1 = temp; | |
247 | temp += temp; | |
248 | h1 += (temp < l1); | |
249 | *lv = temp; | |
250 | *hv = h1; | |
251 | return; | |
252 | } | |
253 | } | |
254 | ||
255 | encode (arg1, l1, h1); | |
256 | encode (arg2, l2, h2); | |
257 | ||
258 | bzero (prod, sizeof prod); | |
259 | ||
260 | for (i = 0; i < 8; i++) | |
261 | for (j = 0; j < 8; j++) | |
262 | { | |
263 | k = i + j; | |
264 | carry = arg1[i] * arg2[j]; | |
265 | while (carry) | |
266 | { | |
267 | carry += prod[k]; | |
268 | prod[k] = carry & 0xff; | |
269 | carry >>= 8; | |
270 | k++; | |
271 | } | |
272 | } | |
273 | ||
274 | decode (prod, lv, hv); /* @@decode ignores prod[8] -> prod[15] */ | |
275 | } | |
276 | \f | |
277 | /* Shift the 64-bit integer in L1, H1 left by COUNT places | |
278 | keeping only PREC bits of result. | |
279 | Shift right if COUNT is negative. | |
280 | ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. | |
281 | Store the value as two `int' pieces in *LV and *HV. */ | |
282 | ||
283 | void | |
284 | lshift_double (l1, h1, count, prec, lv, hv, arith) | |
285 | int l1, h1, count, prec; | |
286 | int *lv, *hv; | |
287 | int arith; | |
288 | { | |
289 | short arg1[8]; | |
290 | register int i; | |
291 | register int carry; | |
292 | ||
293 | if (count < 0) | |
294 | { | |
295 | rshift_double (l1, h1, - count, prec, lv, hv, arith); | |
296 | return; | |
297 | } | |
298 | ||
299 | encode (arg1, l1, h1); | |
300 | ||
301 | if (count > prec) | |
302 | count = prec; | |
303 | ||
304 | while (count > 0) | |
305 | { | |
306 | carry = 0; | |
307 | for (i = 0; i < 8; i++) | |
308 | { | |
309 | carry += arg1[i] << 1; | |
310 | arg1[i] = carry & 0xff; | |
311 | carry >>= 8; | |
312 | } | |
313 | count--; | |
314 | } | |
315 | ||
316 | decode (arg1, lv, hv); | |
317 | } | |
318 | ||
319 | /* Shift the 64-bit integer in L1, H1 right by COUNT places | |
320 | keeping only PREC bits of result. COUNT must be positive. | |
321 | ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. | |
322 | Store the value as two `int' pieces in *LV and *HV. */ | |
323 | ||
324 | void | |
325 | rshift_double (l1, h1, count, prec, lv, hv, arith) | |
326 | int l1, h1, count, prec; | |
327 | int *lv, *hv; | |
328 | int arith; | |
329 | { | |
330 | short arg1[8]; | |
331 | register int i; | |
332 | register int carry; | |
333 | ||
334 | encode (arg1, l1, h1); | |
335 | ||
336 | if (count > prec) | |
337 | count = prec; | |
338 | ||
339 | while (count > 0) | |
340 | { | |
341 | carry = arith && arg1[7] >> 7; | |
342 | for (i = 7; i >= 0; i--) | |
343 | { | |
344 | carry <<= 8; | |
345 | carry += arg1[i]; | |
346 | arg1[i] = (carry >> 1) & 0xff; | |
347 | } | |
348 | count--; | |
349 | } | |
350 | ||
351 | decode (arg1, lv, hv); | |
352 | } | |
353 | \f | |
354 | /* Rotate the 64-bit integer in L1, H1 left by COUNT places | |
355 | keeping only PREC bits of result. | |
356 | Rotate right if COUNT is negative. | |
357 | Store the value as two `int' pieces in *LV and *HV. */ | |
358 | ||
359 | void | |
360 | lrotate_double (l1, h1, count, prec, lv, hv) | |
361 | int l1, h1, count, prec; | |
362 | int *lv, *hv; | |
363 | { | |
364 | short arg1[8]; | |
365 | register int i; | |
366 | register int carry; | |
367 | ||
368 | if (count < 0) | |
369 | { | |
370 | rrotate_double (l1, h1, - count, prec, lv, hv); | |
371 | return; | |
372 | } | |
373 | ||
374 | encode (arg1, l1, h1); | |
375 | ||
376 | if (count > prec) | |
377 | count = prec; | |
378 | ||
379 | carry = arg1[7] >> 7; | |
380 | while (count > 0) | |
381 | { | |
382 | for (i = 0; i < 8; i++) | |
383 | { | |
384 | carry += arg1[i] << 1; | |
385 | arg1[i] = carry & 0xff; | |
386 | carry >>= 8; | |
387 | } | |
388 | count--; | |
389 | } | |
390 | ||
391 | decode (arg1, lv, hv); | |
392 | } | |
393 | ||
394 | /* Rotate the 64-bit integer in L1, H1 left by COUNT places | |
395 | keeping only PREC bits of result. COUNT must be positive. | |
396 | Store the value as two `int' pieces in *LV and *HV. */ | |
397 | ||
398 | void | |
399 | rrotate_double (l1, h1, count, prec, lv, hv) | |
400 | int l1, h1, count, prec; | |
401 | int *lv, *hv; | |
402 | { | |
403 | short arg1[8]; | |
404 | register int i; | |
405 | register int carry; | |
406 | ||
407 | encode (arg1, l1, h1); | |
408 | ||
409 | if (count > prec) | |
410 | count = prec; | |
411 | ||
412 | carry = arg1[0] & 1; | |
413 | while (count > 0) | |
414 | { | |
415 | for (i = 7; i >= 0; i--) | |
416 | { | |
417 | carry <<= 8; | |
418 | carry += arg1[i]; | |
419 | arg1[i] = (carry >> 1) & 0xff; | |
420 | } | |
421 | count--; | |
422 | } | |
423 | ||
424 | decode (arg1, lv, hv); | |
425 | } | |
426 | \f | |
427 | /* Divide 64 bit integer LNUM, HNUM by 64 bit integer LDEN, HDEN | |
428 | for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM). | |
429 | CODE is a tree code for a kind of division, one of | |
430 | TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR | |
431 | or EXACT_DIV_EXPR | |
432 | It controls how the quotient is rounded to a integer. | |
433 | UNS nonzero says do unsigned division. */ | |
434 | ||
435 | static void | |
436 | div_and_round_double (code, uns, | |
437 | lnum_orig, hnum_orig, lden_orig, hden_orig, | |
438 | lquo, hquo, lrem, hrem) | |
439 | enum tree_code code; | |
440 | int uns; | |
441 | int lnum_orig, hnum_orig; /* num == numerator == dividend */ | |
442 | int lden_orig, hden_orig; /* den == denominator == divisor */ | |
443 | int *lquo, *hquo, *lrem, *hrem; | |
444 | { | |
445 | int quo_neg = 0; | |
446 | short num[9], den[8], quo[8]; /* extra element for scaling. */ | |
447 | register int i, j, work; | |
448 | register int carry = 0; | |
449 | unsigned int lnum = lnum_orig; | |
450 | int hnum = hnum_orig; | |
451 | unsigned int lden = lden_orig; | |
452 | int hden = hden_orig; | |
453 | ||
454 | if ((hden == 0) && (lden == 0)) | |
455 | abort (); | |
456 | ||
457 | /* calculate quotient sign and convert operands to unsigned. */ | |
458 | if (!uns) | |
459 | { | |
460 | if (hden < 0) | |
461 | { | |
462 | quo_neg = ~ quo_neg; | |
463 | neg_double (lden, hden, &lden, &hden); | |
464 | } | |
465 | if (hnum < 0) | |
466 | { | |
467 | quo_neg = ~ quo_neg; | |
468 | neg_double (lnum, hnum, &lnum, &hnum); | |
469 | } | |
470 | } | |
471 | ||
472 | if (hnum == 0 && hden == 0) | |
473 | { /* single precision */ | |
474 | *hquo = *hrem = 0; | |
475 | *lquo = lnum / lden; /* rounds toward zero since positive args */ | |
476 | goto finish_up; | |
477 | } | |
478 | ||
479 | if (hnum == 0) | |
480 | { /* trivial case: dividend < divisor */ | |
481 | /* hden != 0 already checked. */ | |
482 | *hquo = *lquo = 0; | |
483 | *hrem = hnum; | |
484 | *lrem = lnum; | |
485 | goto finish_up; | |
486 | } | |
487 | ||
488 | bzero (quo, sizeof quo); | |
489 | ||
490 | bzero (num, sizeof num); /* to zero 9th element */ | |
491 | bzero (den, sizeof den); | |
492 | ||
493 | encode (num, lnum, hnum); | |
494 | encode (den, lden, hden); | |
495 | ||
496 | /* This code requires more than just hden == 0. | |
497 | We also have to require that we don't need more than three bytes | |
498 | to hold CARRY. If we ever did need four bytes to hold it, we | |
499 | would lose part of it when computing WORK on the next round. */ | |
500 | if (hden == 0 && ((lden << 8) >> 8) == lden) | |
501 | { /* simpler algorithm */ | |
502 | /* hnum != 0 already checked. */ | |
503 | for (i = 7; i >= 0; i--) | |
504 | { | |
505 | work = num[i] + (carry << 8); | |
506 | quo[i] = work / lden; | |
507 | carry = work % lden; | |
508 | } | |
509 | } | |
510 | else { /* full double precision, | |
511 | with thanks to Don Knuth's | |
512 | "Semi-Numericial Algorithms". */ | |
513 | #define BASE 256 | |
514 | int quo_est, scale, num_hi_sig, den_hi_sig, quo_hi_sig; | |
515 | ||
516 | /* Find the highest non-zero divisor digit. */ | |
517 | for (i = 7; ; i--) | |
518 | if (den[i] != 0) { | |
519 | den_hi_sig = i; | |
520 | break; | |
521 | } | |
522 | for (i = 7; ; i--) | |
523 | if (num[i] != 0) { | |
524 | num_hi_sig = i; | |
525 | break; | |
526 | } | |
527 | quo_hi_sig = num_hi_sig - den_hi_sig + 1; | |
528 | ||
529 | /* Insure that the first digit of the divisor is at least BASE/2. | |
530 | This is required by the quotient digit estimation algorithm. */ | |
531 | ||
532 | scale = BASE / (den[den_hi_sig] + 1); | |
533 | if (scale > 1) { /* scale divisor and dividend */ | |
534 | carry = 0; | |
535 | for (i = 0; i <= 8; i++) { | |
536 | work = (num[i] * scale) + carry; | |
537 | num[i] = work & 0xff; | |
538 | carry = work >> 8; | |
539 | if (num[i] != 0) num_hi_sig = i; | |
540 | } | |
541 | carry = 0; | |
542 | for (i = 0; i <= 7; i++) { | |
543 | work = (den[i] * scale) + carry; | |
544 | den[i] = work & 0xff; | |
545 | carry = work >> 8; | |
546 | if (den[i] != 0) den_hi_sig = i; | |
547 | } | |
548 | } | |
549 | ||
550 | /* Main loop */ | |
551 | for (i = quo_hi_sig; i > 0; i--) { | |
552 | /* quess the next quotient digit, quo_est, by dividing the first | |
553 | two remaining dividend digits by the high order quotient digit. | |
554 | quo_est is never low and is at most 2 high. */ | |
555 | ||
556 | int num_hi; /* index of highest remaining dividend digit */ | |
557 | ||
558 | num_hi = i + den_hi_sig; | |
559 | ||
560 | work = (num[num_hi] * BASE) + (num_hi > 0 ? num[num_hi - 1] : 0); | |
561 | if (num[num_hi] != den[den_hi_sig]) { | |
562 | quo_est = work / den[den_hi_sig]; | |
563 | } | |
564 | else { | |
565 | quo_est = BASE - 1; | |
566 | } | |
567 | ||
568 | /* refine quo_est so it's usually correct, and at most one high. */ | |
569 | while ((den[den_hi_sig - 1] * quo_est) | |
570 | > (((work - (quo_est * den[den_hi_sig])) * BASE) | |
571 | + ((num_hi - 1) > 0 ? num[num_hi - 2] : 0))) | |
572 | quo_est--; | |
573 | ||
574 | /* Try QUO_EST as the quotient digit, by multiplying the | |
575 | divisor by QUO_EST and subtracting from the remaining dividend. | |
576 | Keep in mind that QUO_EST is the I - 1st digit. */ | |
577 | ||
578 | carry = 0; | |
579 | ||
580 | for (j = 0; j <= den_hi_sig; j++) | |
581 | { | |
582 | int digit; | |
583 | ||
584 | work = num[i + j - 1] - (quo_est * den[j]) + carry; | |
585 | digit = work & 0xff; | |
586 | carry = work >> 8; | |
587 | if (digit < 0) | |
588 | { | |
589 | digit += BASE; | |
590 | carry--; | |
591 | } | |
592 | num[i + j - 1] = digit; | |
593 | } | |
594 | ||
595 | /* if quo_est was high by one, then num[i] went negative and | |
596 | we need to correct things. */ | |
597 | ||
598 | if (num[num_hi] < 0) | |
599 | { | |
600 | quo_est--; | |
601 | carry = 0; /* add divisor back in */ | |
602 | for (j = 0; j <= den_hi_sig; j++) | |
603 | { | |
604 | work = num[i + j - 1] + den[j] + carry; | |
605 | if (work > BASE) | |
606 | { | |
607 | work -= BASE; | |
608 | carry = 1; | |
609 | } | |
610 | else | |
611 | { | |
612 | carry = 0; | |
613 | } | |
614 | num[i + j - 1] = work; | |
615 | } | |
616 | num [num_hi] += carry; | |
617 | } | |
618 | ||
619 | /* store the quotient digit. */ | |
620 | quo[i - 1] = quo_est; | |
621 | } | |
622 | } | |
623 | ||
624 | decode (quo, lquo, hquo); | |
625 | ||
626 | finish_up: | |
627 | /* if result is negative, make it so. */ | |
628 | if (quo_neg) | |
629 | neg_double (*lquo, *hquo, lquo, hquo); | |
630 | ||
631 | /* compute trial remainder: rem = num - (quo * den) */ | |
632 | mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); | |
633 | neg_double (*lrem, *hrem, lrem, hrem); | |
634 | add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); | |
635 | ||
636 | switch (code) | |
637 | { | |
638 | case TRUNC_DIV_EXPR: | |
639 | case TRUNC_MOD_EXPR: /* round toward zero */ | |
640 | case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */ | |
641 | return; | |
642 | ||
643 | case FLOOR_DIV_EXPR: | |
644 | case FLOOR_MOD_EXPR: /* round toward negative infinity */ | |
645 | if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */ | |
646 | { | |
647 | /* quo = quo - 1; */ | |
648 | add_double (*lquo, *hquo, -1, -1, lquo, hquo); | |
649 | } | |
650 | else return; | |
651 | break; | |
652 | ||
653 | case CEIL_DIV_EXPR: | |
654 | case CEIL_MOD_EXPR: /* round toward positive infinity */ | |
655 | if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */ | |
656 | { | |
657 | add_double (*lquo, *hquo, 1, 0, lquo, hquo); | |
658 | } | |
659 | else return; | |
660 | break; | |
661 | ||
662 | case ROUND_DIV_EXPR: | |
663 | case ROUND_MOD_EXPR: /* round to closest integer */ | |
664 | { | |
665 | int labs_rem = *lrem, habs_rem = *hrem; | |
666 | int labs_den = lden, habs_den = hden, ltwice, htwice; | |
667 | ||
668 | /* get absolute values */ | |
669 | if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem); | |
670 | if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den); | |
671 | ||
672 | /* if (2 * abs (lrem) >= abs (lden)) */ | |
673 | mul_double (2, 0, labs_rem, habs_rem, <wice, &htwice); | |
674 | if (((unsigned) habs_den < (unsigned) htwice) | |
675 | || (((unsigned) habs_den == (unsigned) htwice) | |
676 | && ((unsigned) labs_den < (unsigned) ltwice))) | |
677 | { | |
678 | if (*hquo < 0) | |
679 | /* quo = quo - 1; */ | |
680 | add_double (*lquo, *hquo, -1, -1, lquo, hquo); | |
681 | else | |
682 | /* quo = quo + 1; */ | |
683 | add_double (*lquo, *hquo, 1, 0, lquo, hquo); | |
684 | } | |
685 | else return; | |
686 | } | |
687 | break; | |
688 | ||
689 | default: | |
690 | abort (); | |
691 | } | |
692 | ||
693 | /* compute true remainder: rem = num - (quo * den) */ | |
694 | mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); | |
695 | neg_double (*lrem, *hrem, lrem, hrem); | |
696 | add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); | |
697 | } | |
698 | \f | |
699 | #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT | |
700 | ||
701 | /* Check for infinity in an IEEE double precision number. */ | |
702 | ||
703 | int | |
704 | target_isinf (x) | |
705 | REAL_VALUE_TYPE x; | |
706 | { | |
707 | /* The IEEE 64-bit double format. */ | |
708 | union { | |
709 | REAL_VALUE_TYPE d; | |
710 | struct { | |
711 | unsigned sign : 1; | |
712 | unsigned exponent : 11; | |
713 | unsigned mantissa1 : 20; | |
714 | unsigned mantissa2; | |
715 | } little_endian; | |
716 | struct { | |
717 | unsigned mantissa2; | |
718 | unsigned mantissa1 : 20; | |
719 | unsigned exponent : 11; | |
720 | unsigned sign : 1; | |
721 | } big_endian; | |
722 | } u; | |
723 | ||
724 | u.d = dconstm1; | |
725 | if (u.big_endian.sign == 1) | |
726 | { | |
727 | u.d = x; | |
728 | return (u.big_endian.exponent == 2047 | |
729 | && u.big_endian.mantissa1 == 0 | |
730 | && u.big_endian.mantissa2 == 0); | |
731 | } | |
732 | else | |
733 | { | |
734 | u.d = x; | |
735 | return (u.little_endian.exponent == 2047 | |
736 | && u.little_endian.mantissa1 == 0 | |
737 | && u.little_endian.mantissa2 == 0); | |
738 | } | |
739 | } | |
740 | ||
741 | /* Check for minus zero in an IEEE double precision number. */ | |
742 | ||
743 | int | |
744 | target_minus_zero (x) | |
745 | REAL_VALUE_TYPE x; | |
746 | { | |
747 | REAL_VALUE_TYPE d1, d2; | |
748 | ||
749 | d1 = REAL_VALUE_NEGATE (x); | |
750 | d2 = dconst0; | |
751 | ||
752 | return !bcmp (&d1, &d2, sizeof (d1)); | |
753 | } | |
754 | #else /* Target not IEEE */ | |
755 | ||
756 | /* Let's assume other float formats don't have infinity. | |
757 | (This can be overridden by redefining REAL_VALUE_ISINF.) */ | |
758 | ||
759 | target_isinf (x) | |
760 | REAL_VALUE_TYPE x; | |
761 | { | |
762 | return 0; | |
763 | } | |
764 | ||
765 | /* Let's assume other float formats don't have minus zero. | |
766 | (This can be overridden by redefining REAL_VALUE_MINUS_ZERO.) */ | |
767 | ||
768 | target_minus_zero (x) | |
769 | REAL_VALUE_TYPE x; | |
770 | { | |
771 | return 0; | |
772 | } | |
773 | #endif /* Target not IEEE */ | |
774 | \f | |
775 | /* Split a tree IN into a constant and a variable part | |
776 | that could be combined with CODE to make IN. | |
777 | CODE must be a commutative arithmetic operation. | |
778 | Store the constant part into *CONP and the variable in &VARP. | |
779 | Return 1 if this was done; zero means the tree IN did not decompose | |
780 | this way. | |
781 | ||
782 | If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. | |
783 | Therefore, we must tell the caller whether the variable part | |
784 | was subtracted. We do this by storing 1 or -1 into *VARSIGNP. | |
785 | The value stored is the coefficient for the variable term. | |
786 | The constant term we return should always be added; | |
787 | we negate it if necessary. */ | |
788 | ||
789 | static int | |
790 | split_tree (in, code, varp, conp, varsignp) | |
791 | tree in; | |
792 | enum tree_code code; | |
793 | tree *varp, *conp; | |
794 | int *varsignp; | |
795 | { | |
796 | register tree outtype = TREE_TYPE (in); | |
797 | *varp = 0; | |
798 | *conp = 0; | |
799 | ||
800 | /* Strip any conversions that don't change the machine mode. */ | |
801 | while ((TREE_CODE (in) == NOP_EXPR | |
802 | || TREE_CODE (in) == CONVERT_EXPR) | |
803 | && (TYPE_MODE (TREE_TYPE (in)) | |
804 | == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0))))) | |
805 | in = TREE_OPERAND (in, 0); | |
806 | ||
807 | if (TREE_CODE (in) == code | |
808 | || (TREE_CODE (TREE_TYPE (in)) != REAL_TYPE | |
809 | /* We can associate addition and subtraction together | |
810 | (even though the C standard doesn't say so) | |
811 | for integers because the value is not affected. | |
812 | For reals, the value might be affected, so we can't. */ | |
813 | && | |
814 | ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR) | |
815 | || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR)))) | |
816 | { | |
817 | enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0)); | |
818 | if (code == INTEGER_CST) | |
819 | { | |
820 | *conp = TREE_OPERAND (in, 0); | |
821 | *varp = TREE_OPERAND (in, 1); | |
822 | if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) | |
823 | && TREE_TYPE (*varp) != outtype) | |
824 | *varp = convert (outtype, *varp); | |
825 | *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; | |
826 | return 1; | |
827 | } | |
828 | if (TREE_CONSTANT (TREE_OPERAND (in, 1))) | |
829 | { | |
830 | *conp = TREE_OPERAND (in, 1); | |
831 | *varp = TREE_OPERAND (in, 0); | |
832 | *varsignp = 1; | |
833 | if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) | |
834 | && TREE_TYPE (*varp) != outtype) | |
835 | *varp = convert (outtype, *varp); | |
836 | if (TREE_CODE (in) == MINUS_EXPR) | |
837 | { | |
838 | /* If operation is subtraction and constant is second, | |
839 | must negate it to get an additive constant. | |
840 | And this cannot be done unless it is a manifest constant. | |
841 | It could also be the address of a static variable. | |
842 | We cannot negate that, so give up. */ | |
843 | if (TREE_CODE (*conp) == INTEGER_CST) | |
844 | /* Subtracting from integer_zero_node loses for long long. */ | |
845 | *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp)); | |
846 | else | |
847 | return 0; | |
848 | } | |
849 | return 1; | |
850 | } | |
851 | if (TREE_CONSTANT (TREE_OPERAND (in, 0))) | |
852 | { | |
853 | *conp = TREE_OPERAND (in, 0); | |
854 | *varp = TREE_OPERAND (in, 1); | |
855 | if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) | |
856 | && TREE_TYPE (*varp) != outtype) | |
857 | *varp = convert (outtype, *varp); | |
858 | *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; | |
859 | return 1; | |
860 | } | |
861 | } | |
862 | return 0; | |
863 | } | |
864 | \f | |
865 | /* Combine two constants NUM and ARG2 under operation CODE | |
866 | to produce a new constant. | |
867 | We assume ARG1 and ARG2 have the same data type, | |
868 | or at least are the same kind of constant and the same machine mode. */ | |
869 | ||
870 | /* Handle floating overflow for `const_binop'. */ | |
871 | static jmp_buf const_binop_error; | |
872 | ||
873 | static tree | |
874 | const_binop (code, arg1, arg2) | |
875 | enum tree_code code; | |
876 | register tree arg1, arg2; | |
877 | { | |
878 | if (TREE_CODE (arg1) == INTEGER_CST) | |
879 | { | |
880 | register int int1l = TREE_INT_CST_LOW (arg1); | |
881 | register int int1h = TREE_INT_CST_HIGH (arg1); | |
882 | int int2l = TREE_INT_CST_LOW (arg2); | |
883 | int int2h = TREE_INT_CST_HIGH (arg2); | |
884 | int low, hi; | |
885 | int garbagel, garbageh; | |
886 | register tree t; | |
887 | int uns = TREE_UNSIGNED (TREE_TYPE (arg1)); | |
888 | ||
889 | switch (code) | |
890 | { | |
891 | case BIT_IOR_EXPR: | |
892 | t = build_int_2 (int1l | int2l, int1h | int2h); | |
893 | break; | |
894 | ||
895 | case BIT_XOR_EXPR: | |
896 | t = build_int_2 (int1l ^ int2l, int1h ^ int2h); | |
897 | break; | |
898 | ||
899 | case BIT_AND_EXPR: | |
900 | t = build_int_2 (int1l & int2l, int1h & int2h); | |
901 | break; | |
902 | ||
903 | case BIT_ANDTC_EXPR: | |
904 | t = build_int_2 (int1l & ~int2l, int1h & ~int2h); | |
905 | break; | |
906 | ||
907 | case RSHIFT_EXPR: | |
908 | int2l = - int2l; | |
909 | case LSHIFT_EXPR: | |
910 | lshift_double (int1l, int1h, int2l, | |
911 | TYPE_PRECISION (TREE_TYPE (arg1)), | |
912 | &low, &hi, | |
913 | !uns); | |
914 | t = build_int_2 (low, hi); | |
915 | break; | |
916 | ||
917 | case RROTATE_EXPR: | |
918 | int2l = - int2l; | |
919 | case LROTATE_EXPR: | |
920 | lrotate_double (int1l, int1h, int2l, | |
921 | TYPE_PRECISION (TREE_TYPE (arg1)), | |
922 | &low, &hi); | |
923 | t = build_int_2 (low, hi); | |
924 | break; | |
925 | ||
926 | case PLUS_EXPR: | |
927 | if (int1h == 0) | |
928 | { | |
929 | int2l += int1l; | |
930 | if ((unsigned) int2l < int1l) | |
931 | int2h += 1; | |
932 | t = build_int_2 (int2l, int2h); | |
933 | break; | |
934 | } | |
935 | if (int2h == 0) | |
936 | { | |
937 | int1l += int2l; | |
938 | if ((unsigned) int1l < int2l) | |
939 | int1h += 1; | |
940 | t = build_int_2 (int1l, int1h); | |
941 | break; | |
942 | } | |
943 | add_double (int1l, int1h, int2l, int2h, &low, &hi); | |
944 | t = build_int_2 (low, hi); | |
945 | break; | |
946 | ||
947 | case MINUS_EXPR: | |
948 | if (int2h == 0 && int2l == 0) | |
949 | { | |
950 | t = build_int_2 (int1l, int1h); | |
951 | break; | |
952 | } | |
953 | neg_double (int2l, int2h, &int2l, &int2h); | |
954 | add_double (int1l, int1h, int2l, int2h, &low, &hi); | |
955 | t = build_int_2 (low, hi); | |
956 | break; | |
957 | ||
958 | case MULT_EXPR: | |
959 | /* Optimize simple cases. */ | |
960 | if (int1h == 0) | |
961 | { | |
962 | unsigned temp; | |
963 | ||
964 | switch (int1l) | |
965 | { | |
966 | case 0: | |
967 | t = build_int_2 (0, 0); | |
968 | goto got_it; | |
969 | case 1: | |
970 | t = build_int_2 (int2l, int2h); | |
971 | goto got_it; | |
972 | case 2: | |
973 | temp = int2l + int2l; | |
974 | int2h = int2h * 2 + (temp < int2l); | |
975 | t = build_int_2 (temp, int2h); | |
976 | goto got_it; | |
977 | case 3: | |
978 | temp = int2l + int2l + int2l; | |
979 | int2h = int2h * 3 + (temp < int2l); | |
980 | t = build_int_2 (temp, int2h); | |
981 | goto got_it; | |
982 | case 4: | |
983 | temp = int2l + int2l; | |
984 | int2h = int2h * 4 + ((temp < int2l) << 1); | |
985 | int2l = temp; | |
986 | temp += temp; | |
987 | int2h += (temp < int2l); | |
988 | t = build_int_2 (temp, int2h); | |
989 | goto got_it; | |
990 | case 8: | |
991 | temp = int2l + int2l; | |
992 | int2h = int2h * 8 + ((temp < int2l) << 2); | |
993 | int2l = temp; | |
994 | temp += temp; | |
995 | int2h += (temp < int2l) << 1; | |
996 | int2l = temp; | |
997 | temp += temp; | |
998 | int2h += (temp < int2l); | |
999 | t = build_int_2 (temp, int2h); | |
1000 | goto got_it; | |
1001 | default: | |
1002 | break; | |
1003 | } | |
1004 | } | |
1005 | ||
1006 | if (int2h == 0) | |
1007 | { | |
1008 | if (int2l == 0) | |
1009 | { | |
1010 | t = build_int_2 (0, 0); | |
1011 | break; | |
1012 | } | |
1013 | if (int2l == 1) | |
1014 | { | |
1015 | t = build_int_2 (int1l, int1h); | |
1016 | break; | |
1017 | } | |
1018 | } | |
1019 | ||
1020 | mul_double (int1l, int1h, int2l, int2h, &low, &hi); | |
1021 | t = build_int_2 (low, hi); | |
1022 | break; | |
1023 | ||
1024 | case TRUNC_DIV_EXPR: | |
1025 | case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR: | |
1026 | case EXACT_DIV_EXPR: | |
1027 | /* This is a shortcut for a common special case. | |
1028 | It reduces the number of tree nodes generated | |
1029 | and saves time. */ | |
1030 | if (int2h == 0 && int2l > 0 | |
1031 | && TREE_TYPE (arg1) == sizetype | |
1032 | && int1h == 0 && int1l >= 0) | |
1033 | { | |
1034 | if (code == CEIL_DIV_EXPR) | |
1035 | int1l += int2l-1; | |
1036 | return size_int (int1l / int2l); | |
1037 | } | |
1038 | case ROUND_DIV_EXPR: | |
1039 | if (int2h == 0 && int2l == 1) | |
1040 | { | |
1041 | t = build_int_2 (int1l, int1h); | |
1042 | break; | |
1043 | } | |
1044 | if (int1l == int2l && int1h == int2h) | |
1045 | { | |
1046 | if ((int1l | int1h) == 0) | |
1047 | abort (); | |
1048 | t = build_int_2 (1, 0); | |
1049 | break; | |
1050 | } | |
1051 | div_and_round_double (code, uns, int1l, int1h, int2l, int2h, | |
1052 | &low, &hi, &garbagel, &garbageh); | |
1053 | t = build_int_2 (low, hi); | |
1054 | break; | |
1055 | ||
1056 | case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR: | |
1057 | case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR: | |
1058 | div_and_round_double (code, uns, int1l, int1h, int2l, int2h, | |
1059 | &garbagel, &garbageh, &low, &hi); | |
1060 | t = build_int_2 (low, hi); | |
1061 | break; | |
1062 | ||
1063 | case MIN_EXPR: | |
1064 | case MAX_EXPR: | |
1065 | if (uns) | |
1066 | { | |
1067 | low = (((unsigned) int1h < (unsigned) int2h) | |
1068 | || (((unsigned) int1h == (unsigned) int2h) | |
1069 | && ((unsigned) int1l < (unsigned) int2l))); | |
1070 | } | |
1071 | else | |
1072 | { | |
1073 | low = ((int1h < int2h) | |
1074 | || ((int1h == int2h) | |
1075 | && ((unsigned) int1l < (unsigned) int2l))); | |
1076 | } | |
1077 | if (low == (code == MIN_EXPR)) | |
1078 | t = build_int_2 (int1l, int1h); | |
1079 | else | |
1080 | t = build_int_2 (int2l, int2h); | |
1081 | break; | |
1082 | ||
1083 | default: | |
1084 | abort (); | |
1085 | } | |
1086 | got_it: | |
1087 | TREE_TYPE (t) = TREE_TYPE (arg1); | |
1088 | force_fit_type (t); | |
1089 | return t; | |
1090 | } | |
1091 | #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) | |
1092 | if (TREE_CODE (arg1) == REAL_CST) | |
1093 | { | |
1094 | register REAL_VALUE_TYPE d1; | |
1095 | register REAL_VALUE_TYPE d2; | |
1096 | register REAL_VALUE_TYPE value; | |
1097 | ||
1098 | d1 = TREE_REAL_CST (arg1); | |
1099 | d2 = TREE_REAL_CST (arg2); | |
1100 | if (setjmp (const_binop_error)) | |
1101 | { | |
1102 | warning ("floating overflow in constant folding"); | |
1103 | return build (code, TREE_TYPE (arg1), arg1, arg2); | |
1104 | } | |
1105 | set_float_handler (const_binop_error); | |
1106 | ||
1107 | #ifdef REAL_ARITHMETIC | |
1108 | REAL_ARITHMETIC (value, code, d1, d2); | |
1109 | #else | |
1110 | switch (code) | |
1111 | { | |
1112 | case PLUS_EXPR: | |
1113 | value = d1 + d2; | |
1114 | break; | |
1115 | ||
1116 | case MINUS_EXPR: | |
1117 | value = d1 - d2; | |
1118 | break; | |
1119 | ||
1120 | case MULT_EXPR: | |
1121 | value = d1 * d2; | |
1122 | break; | |
1123 | ||
1124 | case RDIV_EXPR: | |
1125 | #ifndef REAL_INFINITY | |
1126 | if (d2 == 0) | |
1127 | abort (); | |
1128 | #endif | |
1129 | ||
1130 | value = d1 / d2; | |
1131 | break; | |
1132 | ||
1133 | case MIN_EXPR: | |
1134 | value = MIN (d1, d2); | |
1135 | break; | |
1136 | ||
1137 | case MAX_EXPR: | |
1138 | value = MAX (d1, d2); | |
1139 | break; | |
1140 | ||
1141 | default: | |
1142 | abort (); | |
1143 | } | |
1144 | #endif /* no REAL_ARITHMETIC */ | |
1145 | set_float_handler (0); | |
1146 | value = REAL_VALUE_TRUNCATE (TYPE_MODE (TREE_TYPE (arg1)), value); | |
1147 | return build_real (TREE_TYPE (arg1), value); | |
1148 | } | |
1149 | #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ | |
1150 | if (TREE_CODE (arg1) == COMPLEX_CST) | |
1151 | { | |
1152 | register tree r1 = TREE_REALPART (arg1); | |
1153 | register tree i1 = TREE_IMAGPART (arg1); | |
1154 | register tree r2 = TREE_REALPART (arg2); | |
1155 | register tree i2 = TREE_IMAGPART (arg2); | |
1156 | register tree t; | |
1157 | ||
1158 | switch (code) | |
1159 | { | |
1160 | case PLUS_EXPR: | |
1161 | t = build_complex (const_binop (PLUS_EXPR, r1, r2), | |
1162 | const_binop (PLUS_EXPR, i1, i2)); | |
1163 | break; | |
1164 | ||
1165 | case MINUS_EXPR: | |
1166 | t = build_complex (const_binop (MINUS_EXPR, r1, r2), | |
1167 | const_binop (MINUS_EXPR, i1, i2)); | |
1168 | break; | |
1169 | ||
1170 | case MULT_EXPR: | |
1171 | t = build_complex (const_binop (MINUS_EXPR, | |
1172 | const_binop (MULT_EXPR, r1, r2), | |
1173 | const_binop (MULT_EXPR, i1, i2)), | |
1174 | const_binop (PLUS_EXPR, | |
1175 | const_binop (MULT_EXPR, r1, i2), | |
1176 | const_binop (MULT_EXPR, i1, r2))); | |
1177 | break; | |
1178 | ||
1179 | case RDIV_EXPR: | |
1180 | { | |
1181 | register tree magsquared | |
1182 | = const_binop (PLUS_EXPR, | |
1183 | const_binop (MULT_EXPR, r2, r2), | |
1184 | const_binop (MULT_EXPR, i2, i2)); | |
1185 | t = build_complex (const_binop (RDIV_EXPR, | |
1186 | const_binop (PLUS_EXPR, | |
1187 | const_binop (MULT_EXPR, r1, r2), | |
1188 | const_binop (MULT_EXPR, i1, i2)), | |
1189 | magsquared), | |
1190 | const_binop (RDIV_EXPR, | |
1191 | const_binop (MINUS_EXPR, | |
1192 | const_binop (MULT_EXPR, i1, r2), | |
1193 | const_binop (MULT_EXPR, r1, i2)), | |
1194 | magsquared)); | |
1195 | } | |
1196 | break; | |
1197 | ||
1198 | default: | |
1199 | abort (); | |
1200 | } | |
1201 | TREE_TYPE (t) = TREE_TYPE (arg1); | |
1202 | return t; | |
1203 | } | |
1204 | return 0; | |
1205 | } | |
1206 | \f | |
1207 | /* Return an INTEGER_CST with value V and type from `sizetype'. */ | |
1208 | ||
1209 | tree | |
1210 | size_int (number) | |
1211 | unsigned int number; | |
1212 | { | |
1213 | register tree t; | |
1214 | /* Type-size nodes already made for small sizes. */ | |
1215 | static tree size_table[2*HOST_BITS_PER_INT+1]; | |
1216 | ||
1217 | if (number >= 0 && number < 2*HOST_BITS_PER_INT+1 && size_table[number] != 0) | |
1218 | return size_table[number]; | |
1219 | if (number >= 0 && number < 2*HOST_BITS_PER_INT+1) | |
1220 | { | |
1221 | int temp = allocation_temporary_p (); | |
1222 | ||
1223 | push_obstacks_nochange (); | |
1224 | /* Make this a permanent node. */ | |
1225 | if (temp) | |
1226 | end_temporary_allocation (); | |
1227 | t = build_int_2 (number, 0); | |
1228 | TREE_TYPE (t) = sizetype; | |
1229 | size_table[number] = t; | |
1230 | pop_obstacks (); | |
1231 | } | |
1232 | else | |
1233 | { | |
1234 | t = build_int_2 (number, 0); | |
1235 | TREE_TYPE (t) = sizetype; | |
1236 | } | |
1237 | return t; | |
1238 | } | |
1239 | ||
1240 | /* Combine operands OP1 and OP2 with arithmetic operation CODE. | |
1241 | CODE is a tree code. Data type is taken from `sizetype', | |
1242 | If the operands are constant, so is the result. */ | |
1243 | ||
1244 | tree | |
1245 | size_binop (code, arg0, arg1) | |
1246 | enum tree_code code; | |
1247 | tree arg0, arg1; | |
1248 | { | |
1249 | /* Handle the special case of two integer constants faster. */ | |
1250 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1251 | { | |
1252 | /* And some specific cases even faster than that. */ | |
1253 | if (code == PLUS_EXPR | |
1254 | && TREE_INT_CST_LOW (arg0) == 0 | |
1255 | && TREE_INT_CST_HIGH (arg0) == 0) | |
1256 | return arg1; | |
1257 | if (code == MINUS_EXPR | |
1258 | && TREE_INT_CST_LOW (arg1) == 0 | |
1259 | && TREE_INT_CST_HIGH (arg1) == 0) | |
1260 | return arg0; | |
1261 | if (code == MULT_EXPR | |
1262 | && TREE_INT_CST_LOW (arg0) == 1 | |
1263 | && TREE_INT_CST_HIGH (arg0) == 0) | |
1264 | return arg1; | |
1265 | /* Handle general case of two integer constants. */ | |
1266 | return const_binop (code, arg0, arg1); | |
1267 | } | |
1268 | ||
1269 | if (arg0 == error_mark_node || arg1 == error_mark_node) | |
1270 | return error_mark_node; | |
1271 | ||
1272 | return fold (build (code, sizetype, arg0, arg1)); | |
1273 | } | |
1274 | \f | |
1275 | /* Given T, a tree representing type conversion of ARG1, a constant, | |
1276 | return a constant tree representing the result of conversion. */ | |
1277 | ||
1278 | static tree | |
1279 | fold_convert (t, arg1) | |
1280 | register tree t; | |
1281 | register tree arg1; | |
1282 | { | |
1283 | register tree type = TREE_TYPE (t); | |
1284 | ||
1285 | if (TREE_CODE (type) == POINTER_TYPE | |
1286 | || TREE_CODE (type) == INTEGER_TYPE | |
1287 | || TREE_CODE (type) == ENUMERAL_TYPE) | |
1288 | { | |
1289 | if (TREE_CODE (arg1) == INTEGER_CST) | |
1290 | { | |
1291 | /* Given an integer constant, make new constant with new type, | |
1292 | appropriately sign-extended or truncated. */ | |
1293 | t = build_int_2 (TREE_INT_CST_LOW (arg1), | |
1294 | TREE_INT_CST_HIGH (arg1)); | |
1295 | TREE_TYPE (t) = type; | |
1296 | force_fit_type (t); | |
1297 | } | |
1298 | #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) | |
1299 | else if (TREE_CODE (arg1) == REAL_CST) | |
1300 | { | |
1301 | if (REAL_VALUES_LESS (real_value_from_int_cst (TYPE_MAX_VALUE (type)), | |
1302 | TREE_REAL_CST (arg1)) | |
1303 | || REAL_VALUES_LESS (TREE_REAL_CST (arg1), | |
1304 | real_value_from_int_cst (TYPE_MIN_VALUE (type)))) | |
1305 | { | |
1306 | warning ("real constant out of range for integer conversion"); | |
1307 | return t; | |
1308 | } | |
1309 | #ifndef REAL_ARITHMETIC | |
1310 | { | |
1311 | REAL_VALUE_TYPE d; | |
1312 | int low, high; | |
1313 | int half_word = 1 << (HOST_BITS_PER_INT / 2); | |
1314 | ||
1315 | d = TREE_REAL_CST (arg1); | |
1316 | if (d < 0) | |
1317 | d = -d; | |
1318 | ||
1319 | high = (int) (d / half_word / half_word); | |
1320 | d -= (REAL_VALUE_TYPE) high * half_word * half_word; | |
1321 | low = (unsigned) d; | |
1322 | if (TREE_REAL_CST (arg1) < 0) | |
1323 | neg_double (low, high, &low, &high); | |
1324 | t = build_int_2 (low, high); | |
1325 | } | |
1326 | #else | |
1327 | { | |
1328 | int low, high; | |
1329 | REAL_VALUE_TO_INT (low, high, TREE_REAL_CST (arg1)); | |
1330 | t = build_int_2 (low, high); | |
1331 | } | |
1332 | #endif | |
1333 | TREE_TYPE (t) = type; | |
1334 | force_fit_type (t); | |
1335 | } | |
1336 | #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ | |
1337 | TREE_TYPE (t) = type; | |
1338 | } | |
1339 | else if (TREE_CODE (type) == REAL_TYPE) | |
1340 | { | |
1341 | #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) | |
1342 | if (TREE_CODE (arg1) == INTEGER_CST) | |
1343 | return build_real_from_int_cst (type, arg1); | |
1344 | #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ | |
1345 | if (TREE_CODE (arg1) == REAL_CST) | |
1346 | return build_real (type, REAL_VALUE_TRUNCATE (TYPE_MODE (type), | |
1347 | TREE_REAL_CST (arg1))); | |
1348 | } | |
1349 | TREE_CONSTANT (t) = 1; | |
1350 | return t; | |
1351 | } | |
1352 | \f | |
1353 | /* Return an expr equal to X but certainly not valid as an lvalue. */ | |
1354 | ||
1355 | tree | |
1356 | non_lvalue (x) | |
1357 | tree x; | |
1358 | { | |
1359 | tree result; | |
1360 | ||
1361 | /* These things are certainly not lvalues. */ | |
1362 | if (TREE_CODE (x) == NON_LVALUE_EXPR | |
1363 | || TREE_CODE (x) == INTEGER_CST | |
1364 | || TREE_CODE (x) == REAL_CST | |
1365 | || TREE_CODE (x) == STRING_CST | |
1366 | || TREE_CODE (x) == ADDR_EXPR) | |
1367 | return x; | |
1368 | ||
1369 | result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x); | |
1370 | TREE_CONSTANT (result) = TREE_CONSTANT (x); | |
1371 | return result; | |
1372 | } | |
1373 | ||
1374 | /* Return nonzero if two operands are necessarily equal. | |
1375 | If ONLY_CONST is non-zero, only return non-zero for constants. */ | |
1376 | ||
1377 | int | |
1378 | operand_equal_p (arg0, arg1, only_const) | |
1379 | tree arg0, arg1; | |
1380 | int only_const; | |
1381 | { | |
1382 | /* If both types don't have the same signedness, then we can't consider | |
1383 | them equal. We must check this before the STRIP_NOPS calls | |
1384 | because they may change the signedness of the arguments. */ | |
1385 | if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1))) | |
1386 | return 0; | |
1387 | ||
1388 | STRIP_NOPS (arg0); | |
1389 | STRIP_NOPS (arg1); | |
1390 | ||
1391 | /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal. | |
1392 | We don't care about side effects in that case because the SAVE_EXPR | |
1393 | takes care of that for us. */ | |
1394 | if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1) | |
1395 | return ! only_const; | |
1396 | ||
1397 | if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1)) | |
1398 | return 0; | |
1399 | ||
1400 | if (TREE_CODE (arg0) == TREE_CODE (arg1) | |
1401 | && TREE_CODE (arg0) == ADDR_EXPR | |
1402 | && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0)) | |
1403 | return 1; | |
1404 | ||
1405 | if (TREE_CODE (arg0) == TREE_CODE (arg1) | |
1406 | && TREE_CODE (arg0) == INTEGER_CST | |
1407 | && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1) | |
1408 | && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1)) | |
1409 | return 1; | |
1410 | ||
1411 | if (TREE_CODE (arg0) == TREE_CODE (arg1) | |
1412 | && TREE_CODE (arg0) == REAL_CST | |
1413 | && REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), TREE_REAL_CST (arg1))) | |
1414 | return 1; | |
1415 | ||
1416 | if (only_const) | |
1417 | return 0; | |
1418 | ||
1419 | if (arg0 == arg1) | |
1420 | return 1; | |
1421 | ||
1422 | if (TREE_CODE (arg0) != TREE_CODE (arg1)) | |
1423 | return 0; | |
1424 | /* This is needed for conversions and for COMPONENT_REF. | |
1425 | Might as well play it safe and always test this. */ | |
1426 | if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1))) | |
1427 | return 0; | |
1428 | ||
1429 | switch (TREE_CODE_CLASS (TREE_CODE (arg0))) | |
1430 | { | |
1431 | case '1': | |
1432 | /* Two conversions are equal only if signedness and modes match. */ | |
1433 | if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR) | |
1434 | && (TREE_UNSIGNED (TREE_TYPE (arg0)) | |
1435 | != TREE_UNSIGNED (TREE_TYPE (arg1)))) | |
1436 | return 0; | |
1437 | ||
1438 | return operand_equal_p (TREE_OPERAND (arg0, 0), | |
1439 | TREE_OPERAND (arg1, 0), 0); | |
1440 | ||
1441 | case '<': | |
1442 | case '2': | |
1443 | return (operand_equal_p (TREE_OPERAND (arg0, 0), | |
1444 | TREE_OPERAND (arg1, 0), 0) | |
1445 | && operand_equal_p (TREE_OPERAND (arg0, 1), | |
1446 | TREE_OPERAND (arg1, 1), 0)); | |
1447 | ||
1448 | case 'r': | |
1449 | switch (TREE_CODE (arg0)) | |
1450 | { | |
1451 | case INDIRECT_REF: | |
1452 | return operand_equal_p (TREE_OPERAND (arg0, 0), | |
1453 | TREE_OPERAND (arg1, 0), 0); | |
1454 | ||
1455 | case COMPONENT_REF: | |
1456 | case ARRAY_REF: | |
1457 | return (operand_equal_p (TREE_OPERAND (arg0, 0), | |
1458 | TREE_OPERAND (arg1, 0), 0) | |
1459 | && operand_equal_p (TREE_OPERAND (arg0, 1), | |
1460 | TREE_OPERAND (arg1, 1), 0)); | |
1461 | ||
1462 | case BIT_FIELD_REF: | |
1463 | return (operand_equal_p (TREE_OPERAND (arg0, 0), | |
1464 | TREE_OPERAND (arg1, 0), 0) | |
1465 | && operand_equal_p (TREE_OPERAND (arg0, 1), | |
1466 | TREE_OPERAND (arg1, 1), 0) | |
1467 | && operand_equal_p (TREE_OPERAND (arg0, 2), | |
1468 | TREE_OPERAND (arg1, 2), 0)); | |
1469 | } | |
1470 | break; | |
1471 | } | |
1472 | ||
1473 | return 0; | |
1474 | } | |
1475 | ||
1476 | /* Return nonzero if comparing COMP1 with COMP2 | |
1477 | gives the same result as comparing OP1 with OP2. | |
1478 | When in doubt, return 0. */ | |
1479 | ||
1480 | static int | |
1481 | comparison_equiv_p (comp1, comp2, op1, op2) | |
1482 | tree comp1, comp2, op1, op2; | |
1483 | { | |
1484 | int unsignedp1, unsignedp2; | |
1485 | tree primop1, primop2; | |
1486 | int correct_width; | |
1487 | ||
1488 | if (operand_equal_p (comp1, op1, 0) | |
1489 | && operand_equal_p (comp2, op2, 0)) | |
1490 | return 1; | |
1491 | ||
1492 | if (TREE_CODE (TREE_TYPE (op1)) != INTEGER_TYPE) | |
1493 | return 0; | |
1494 | ||
1495 | if (TREE_TYPE (op1) != TREE_TYPE (op2)) | |
1496 | return 0; | |
1497 | ||
1498 | if (TREE_TYPE (comp1) != TREE_TYPE (comp2)) | |
1499 | return 0; | |
1500 | ||
1501 | /* Duplicate what shorten_compare does to the comparison operands, | |
1502 | and see if that gives the actual comparison operands, COMP1 and COMP2. */ | |
1503 | ||
1504 | /* Throw away any conversions to wider types | |
1505 | already present in the operands. */ | |
1506 | primop1 = get_narrower (op1, &unsignedp1); | |
1507 | primop2 = get_narrower (op2, &unsignedp2); | |
1508 | ||
1509 | correct_width = TYPE_PRECISION (TREE_TYPE (op2)); | |
1510 | if (unsignedp1 == unsignedp2 | |
1511 | && TYPE_PRECISION (TREE_TYPE (primop1)) < correct_width | |
1512 | && TYPE_PRECISION (TREE_TYPE (primop2)) < correct_width) | |
1513 | { | |
1514 | tree type = TREE_TYPE (comp1); | |
1515 | ||
1516 | /* Make sure shorter operand is extended the right way | |
1517 | to match the longer operand. */ | |
1518 | primop1 = convert (signed_or_unsigned_type (unsignedp1, TREE_TYPE (primop1)), | |
1519 | primop1); | |
1520 | primop2 = convert (signed_or_unsigned_type (unsignedp2, TREE_TYPE (primop2)), | |
1521 | primop2); | |
1522 | ||
1523 | primop1 = convert (type, primop1); | |
1524 | primop2 = convert (type, primop2); | |
1525 | ||
1526 | if (operand_equal_p (comp1, primop1, 0) | |
1527 | && operand_equal_p (comp2, primop2, 0)) | |
1528 | return 1; | |
1529 | } | |
1530 | ||
1531 | return 0; | |
1532 | } | |
1533 | \f | |
1534 | /* Return a tree for the case when the result of an expression is RESULT | |
1535 | converted to TYPE and OMITTED was previously an operand of the expression | |
1536 | but is now not needed (e.g., we folded OMITTED * 0). | |
1537 | ||
1538 | If OMITTED has side effects, we must evaluate it. Otherwise, just do | |
1539 | the conversion of RESULT to TYPE. */ | |
1540 | ||
1541 | static tree | |
1542 | omit_one_operand (type, result, omitted) | |
1543 | tree type, result, omitted; | |
1544 | { | |
1545 | tree t = convert (type, result); | |
1546 | ||
1547 | if (TREE_SIDE_EFFECTS (omitted)) | |
1548 | return build (COMPOUND_EXPR, type, omitted, t); | |
1549 | ||
1550 | return t; | |
1551 | } | |
1552 | \f | |
1553 | /* Return a simplified tree node for the truth-negation of ARG | |
1554 | (perhaps by altering ARG). It is known that ARG is an operation that | |
1555 | returns a truth value (0 or 1). */ | |
1556 | ||
1557 | tree | |
1558 | invert_truthvalue (arg) | |
1559 | tree arg; | |
1560 | { | |
1561 | tree type = TREE_TYPE (arg); | |
1562 | ||
1563 | /* For floating-point comparisons, it isn't safe to invert the condition. | |
1564 | So just enclose a TRUTH_NOT_EXPR around what we have. */ | |
1565 | if (TREE_CODE (type) == REAL_TYPE | |
1566 | && TREE_CODE_CLASS (TREE_CODE (arg)) == '<') | |
1567 | return build1 (TRUTH_NOT_EXPR, type, arg); | |
1568 | ||
1569 | switch (TREE_CODE (arg)) | |
1570 | { | |
1571 | case NE_EXPR: | |
1572 | TREE_SET_CODE (arg, EQ_EXPR); | |
1573 | return arg; | |
1574 | ||
1575 | case EQ_EXPR: | |
1576 | TREE_SET_CODE (arg, NE_EXPR); | |
1577 | return arg; | |
1578 | ||
1579 | case GE_EXPR: | |
1580 | TREE_SET_CODE (arg, LT_EXPR); | |
1581 | return arg; | |
1582 | ||
1583 | case GT_EXPR: | |
1584 | TREE_SET_CODE (arg, LE_EXPR); | |
1585 | return arg; | |
1586 | ||
1587 | case LE_EXPR: | |
1588 | TREE_SET_CODE (arg, GT_EXPR); | |
1589 | return arg; | |
1590 | ||
1591 | case LT_EXPR: | |
1592 | TREE_SET_CODE (arg, GE_EXPR); | |
1593 | return arg; | |
1594 | ||
1595 | case INTEGER_CST: | |
1596 | return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0 | |
1597 | && TREE_INT_CST_HIGH (arg) == 0, 0)); | |
1598 | ||
1599 | case TRUTH_AND_EXPR: | |
1600 | return build (TRUTH_OR_EXPR, type, | |
1601 | invert_truthvalue (TREE_OPERAND (arg, 0)), | |
1602 | invert_truthvalue (TREE_OPERAND (arg, 1))); | |
1603 | ||
1604 | case TRUTH_OR_EXPR: | |
1605 | return build (TRUTH_AND_EXPR, type, | |
1606 | invert_truthvalue (TREE_OPERAND (arg, 0)), | |
1607 | invert_truthvalue (TREE_OPERAND (arg, 1))); | |
1608 | ||
1609 | case TRUTH_ANDIF_EXPR: | |
1610 | return build (TRUTH_ORIF_EXPR, type, | |
1611 | invert_truthvalue (TREE_OPERAND (arg, 0)), | |
1612 | invert_truthvalue (TREE_OPERAND (arg, 1))); | |
1613 | ||
1614 | case TRUTH_ORIF_EXPR: | |
1615 | return build (TRUTH_ANDIF_EXPR, type, | |
1616 | invert_truthvalue (TREE_OPERAND (arg, 0)), | |
1617 | invert_truthvalue (TREE_OPERAND (arg, 1))); | |
1618 | ||
1619 | case TRUTH_NOT_EXPR: | |
1620 | return TREE_OPERAND (arg, 0); | |
1621 | ||
1622 | case COND_EXPR: | |
1623 | return build (COND_EXPR, type, TREE_OPERAND (arg, 0), | |
1624 | invert_truthvalue (TREE_OPERAND (arg, 1)), | |
1625 | invert_truthvalue (TREE_OPERAND (arg, 2))); | |
1626 | ||
1627 | case NON_LVALUE_EXPR: | |
1628 | return invert_truthvalue (TREE_OPERAND (arg, 0)); | |
1629 | ||
1630 | case NOP_EXPR: | |
1631 | case CONVERT_EXPR: | |
1632 | case FLOAT_EXPR: | |
1633 | return build1 (TREE_CODE (arg), type, | |
1634 | invert_truthvalue (TREE_OPERAND (arg, 0))); | |
1635 | ||
1636 | case BIT_AND_EXPR: | |
1637 | if (! integer_onep (TREE_OPERAND (arg, 1))) | |
1638 | abort (); | |
1639 | return build (EQ_EXPR, type, arg, convert (type, integer_zero_node)); | |
1640 | } | |
1641 | ||
1642 | abort (); | |
1643 | } | |
1644 | ||
1645 | /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both | |
1646 | operands are another bit-wise operation with a common input. If so, | |
1647 | distribute the bit operations to save an operation and possibly two if | |
1648 | constants are involved. For example, convert | |
1649 | (A | B) & (A | C) into A | (B & C) | |
1650 | Further simplification will occur if B and C are constants. | |
1651 | ||
1652 | If this optimization cannot be done, 0 will be returned. */ | |
1653 | ||
1654 | static tree | |
1655 | distribute_bit_expr (code, type, arg0, arg1) | |
1656 | enum tree_code code; | |
1657 | tree type; | |
1658 | tree arg0, arg1; | |
1659 | { | |
1660 | tree common; | |
1661 | tree left, right; | |
1662 | ||
1663 | if (TREE_CODE (arg0) != TREE_CODE (arg1) | |
1664 | || TREE_CODE (arg0) == code | |
1665 | || (TREE_CODE (arg0) != BIT_AND_EXPR | |
1666 | && TREE_CODE (arg0) != BIT_IOR_EXPR)) | |
1667 | return 0; | |
1668 | ||
1669 | if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)) | |
1670 | { | |
1671 | common = TREE_OPERAND (arg0, 0); | |
1672 | left = TREE_OPERAND (arg0, 1); | |
1673 | right = TREE_OPERAND (arg1, 1); | |
1674 | } | |
1675 | else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0)) | |
1676 | { | |
1677 | common = TREE_OPERAND (arg0, 0); | |
1678 | left = TREE_OPERAND (arg0, 1); | |
1679 | right = TREE_OPERAND (arg1, 0); | |
1680 | } | |
1681 | else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0)) | |
1682 | { | |
1683 | common = TREE_OPERAND (arg0, 1); | |
1684 | left = TREE_OPERAND (arg0, 0); | |
1685 | right = TREE_OPERAND (arg1, 1); | |
1686 | } | |
1687 | else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0)) | |
1688 | { | |
1689 | common = TREE_OPERAND (arg0, 1); | |
1690 | left = TREE_OPERAND (arg0, 0); | |
1691 | right = TREE_OPERAND (arg1, 0); | |
1692 | } | |
1693 | else | |
1694 | return 0; | |
1695 | ||
1696 | return fold (build (TREE_CODE (arg0), type, common, | |
1697 | fold (build (code, type, left, right)))); | |
1698 | } | |
1699 | \f | |
1700 | /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER | |
1701 | starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */ | |
1702 | ||
1703 | static tree | |
1704 | make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp) | |
1705 | tree inner; | |
1706 | tree type; | |
1707 | int bitsize, bitpos; | |
1708 | int unsignedp; | |
1709 | { | |
1710 | tree result = build (BIT_FIELD_REF, type, inner, | |
1711 | size_int (bitsize), size_int (bitpos)); | |
1712 | ||
1713 | TREE_UNSIGNED (result) = unsignedp; | |
1714 | ||
1715 | return result; | |
1716 | } | |
1717 | ||
1718 | /* Optimize a bit-field compare. | |
1719 | ||
1720 | There are two cases: First is a compare against a constant and the | |
1721 | second is a comparison of two items where the fields are at the same | |
1722 | bit position relative to the start of a chunk (byte, halfword, word) | |
1723 | large enough to contain it. In these cases we can avoid the shift | |
1724 | implicit in bitfield extractions. | |
1725 | ||
1726 | For constants, we emit a compare of the shifted constant with the | |
1727 | BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being | |
1728 | compared. For two fields at the same position, we do the ANDs with the | |
1729 | similar mask and compare the result of the ANDs. | |
1730 | ||
1731 | CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR. | |
1732 | COMPARE_TYPE is the type of the comparison, and LHS and RHS | |
1733 | are the left and right operands of the comparison, respectively. | |
1734 | ||
1735 | If the optimization described above can be done, we return the resuling | |
1736 | tree. Otherwise we return zero. */ | |
1737 | ||
1738 | static tree | |
1739 | optimize_bit_field_compare (code, compare_type, lhs, rhs) | |
1740 | enum tree_code code; | |
1741 | tree compare_type; | |
1742 | tree lhs, rhs; | |
1743 | { | |
1744 | int lbitpos, lbitsize, rbitpos, rbitsize; | |
1745 | int lnbitpos, lnbitsize, rnbitpos, rnbitsize; | |
1746 | tree type = TREE_TYPE (lhs); | |
1747 | tree signed_type, unsigned_type; | |
1748 | int const_p = TREE_CODE (rhs) == INTEGER_CST; | |
1749 | enum machine_mode lmode, rmode, lnmode, rnmode; | |
1750 | int lunsignedp, runsignedp; | |
1751 | int lvolatilep = 0, rvolatilep = 0; | |
1752 | tree linner, rinner; | |
1753 | tree mask; | |
1754 | ||
1755 | /* Get all the information about the extractions being done. If the bit size | |
1756 | if the same as the size of the underlying object, we aren't doing an | |
1757 | extraction at all and so can do nothing. */ | |
1758 | linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &lmode, | |
1759 | &lunsignedp, &lvolatilep); | |
1760 | if (lbitsize == GET_MODE_BITSIZE (lmode)) | |
1761 | return 0; | |
1762 | ||
1763 | if (!const_p) | |
1764 | { | |
1765 | /* If this is not a constant, we can only do something if bit positions, | |
1766 | sizes, and signedness are the same. */ | |
1767 | rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, | |
1768 | &rmode, &runsignedp, &rvolatilep); | |
1769 | ||
1770 | if (lbitpos != rbitpos || lbitsize != rbitsize | |
1771 | || lunsignedp != runsignedp) | |
1772 | return 0; | |
1773 | } | |
1774 | ||
1775 | /* See if we can find a mode to refer to this field. We should be able to, | |
1776 | but fail if we can't. */ | |
1777 | lnmode = get_best_mode (lbitsize, lbitpos, | |
1778 | TYPE_ALIGN (TREE_TYPE (linner)), word_mode, | |
1779 | lvolatilep); | |
1780 | if (lnmode == VOIDmode) | |
1781 | return 0; | |
1782 | ||
1783 | /* Set signed and unsigned types of the precision of this mode for the | |
1784 | shifts below. */ | |
1785 | signed_type = type_for_mode (lnmode, 0); | |
1786 | unsigned_type = type_for_mode (lnmode, 1); | |
1787 | ||
1788 | if (! const_p) | |
1789 | { | |
1790 | rnmode = get_best_mode (rbitsize, rbitpos, | |
1791 | TYPE_ALIGN (TREE_TYPE (rinner)), word_mode, | |
1792 | rvolatilep); | |
1793 | if (rnmode == VOIDmode) | |
1794 | return 0; | |
1795 | } | |
1796 | ||
1797 | /* Compute the bit position and size for the new reference and our offset | |
1798 | within it. If the new reference is the same size as the original, we | |
1799 | won't optimize anything, so return zero. */ | |
1800 | lnbitsize = GET_MODE_BITSIZE (lnmode); | |
1801 | lnbitpos = lbitpos & ~ (lnbitsize - 1); | |
1802 | lbitpos -= lnbitpos; | |
1803 | if (lnbitsize == lbitsize) | |
1804 | return 0; | |
1805 | ||
1806 | if (! const_p) | |
1807 | { | |
1808 | rnbitsize = GET_MODE_BITSIZE (rnmode); | |
1809 | rnbitpos = rbitpos & ~ (rnbitsize - 1); | |
1810 | rbitpos -= rnbitpos; | |
1811 | if (rnbitsize == rbitsize) | |
1812 | return 0; | |
1813 | } | |
1814 | ||
1815 | #if BYTES_BIG_ENDIAN | |
1816 | lbitpos = lnbitsize - lbitsize - lbitpos; | |
1817 | rbitpos = rnbitsize - rbitsize - rbitpos; | |
1818 | #endif | |
1819 | ||
1820 | /* Make the mask to be used against the extracted field. */ | |
1821 | mask = convert (unsigned_type, build_int_2 (~0, ~0)); | |
1822 | mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize)); | |
1823 | mask = const_binop (RSHIFT_EXPR, mask, | |
1824 | size_int (lnbitsize - lbitsize - lbitpos)); | |
1825 | ||
1826 | if (! const_p) | |
1827 | /* If not comparing with constant, just rework the comparison | |
1828 | and return. */ | |
1829 | return build (code, compare_type, | |
1830 | build (BIT_AND_EXPR, type, | |
1831 | make_bit_field_ref (linner, type, | |
1832 | lnbitsize, lnbitpos, lunsignedp), | |
1833 | mask), | |
1834 | build (BIT_AND_EXPR, type, | |
1835 | make_bit_field_ref (rinner, type, | |
1836 | rnbitsize, rnbitpos, runsignedp), | |
1837 | mask)); | |
1838 | ||
1839 | /* Otherwise, we are handling the constant case. See if the constant is too | |
1840 | big for the field. Warn and return a tree of for 0 (false) if so. We do | |
1841 | this not only for its own sake, but to avoid having to test for this | |
1842 | error case below. If we didn't, we might generate wrong code. | |
1843 | ||
1844 | For unsigned fields, the constant shifted right by the field length should | |
1845 | be all zero. For signed fields, the high-order bits should agree with | |
1846 | the sign bit. */ | |
1847 | ||
1848 | if (lunsignedp) | |
1849 | { | |
1850 | if (! integer_zerop (const_binop (RSHIFT_EXPR, | |
1851 | convert (unsigned_type, rhs), | |
1852 | size_int (lbitsize)))) | |
1853 | { | |
1854 | warning ("comparison is always %s due to width of bitfield", | |
1855 | code == NE_EXPR ? "one" : "zero"); | |
1856 | return convert (compare_type, | |
1857 | (code == NE_EXPR | |
1858 | ? integer_one_node : integer_zero_node)); | |
1859 | } | |
1860 | } | |
1861 | else | |
1862 | { | |
1863 | tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs), | |
1864 | size_int (lbitsize - 1)); | |
1865 | if (! integer_zerop (tem) && ! integer_all_onesp (tem)) | |
1866 | { | |
1867 | warning ("comparison is always %s due to width of bitfield", | |
1868 | code == NE_EXPR ? "one" : "zero"); | |
1869 | return convert (compare_type, | |
1870 | (code == NE_EXPR | |
1871 | ? integer_one_node : integer_zero_node)); | |
1872 | } | |
1873 | } | |
1874 | ||
1875 | /* Single-bit compares should always be against zero. */ | |
1876 | if (lbitsize == 1 && ! integer_zerop (rhs)) | |
1877 | { | |
1878 | code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR; | |
1879 | rhs = convert (type, integer_zero_node); | |
1880 | } | |
1881 | ||
1882 | /* Make a new bitfield reference, shift the constant over the | |
1883 | appropriate number of bits and mask it with the computed mask | |
1884 | (in case this was a signed field). If we changed it, make a new one. */ | |
1885 | lhs = make_bit_field_ref (linner, TREE_TYPE (lhs), lnbitsize, lnbitpos, | |
1886 | lunsignedp); | |
1887 | ||
1888 | rhs = fold (build1 (NOP_EXPR, type, | |
1889 | const_binop (BIT_AND_EXPR, | |
1890 | const_binop (LSHIFT_EXPR, | |
1891 | convert (unsigned_type, rhs), | |
1892 | size_int (lbitpos)), mask))); | |
1893 | ||
1894 | return build (code, compare_type, | |
1895 | build (BIT_AND_EXPR, type, lhs, mask), | |
1896 | rhs); | |
1897 | } | |
1898 | \f | |
1899 | /* Subroutine for the following routine: decode a field reference. | |
1900 | ||
1901 | If EXP is a comparison reference, we return the innermost reference. | |
1902 | ||
1903 | *PBITSIZE is set to the number of bits in the reference, *PBITPOS is | |
1904 | set to the starting bit number. | |
1905 | ||
1906 | If the innermost field can be completely contained in a mode-sized | |
1907 | unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode. | |
1908 | ||
1909 | *PVOLATILEP is set to 1 if the any expression encountered is volatile; | |
1910 | otherwise it is not changed. | |
1911 | ||
1912 | *PUNSIGNEDP is set to the signedness of the field. | |
1913 | ||
1914 | *PMASK is set to the mask used. This is either contained in a | |
1915 | BIT_AND_EXPR or derived from the width of the field. | |
1916 | ||
1917 | Return 0 if this is not a component reference or is one that we can't | |
1918 | do anything with. */ | |
1919 | ||
1920 | static tree | |
1921 | decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp, | |
1922 | pvolatilep, pmask) | |
1923 | tree exp; | |
1924 | int *pbitsize, *pbitpos; | |
1925 | enum machine_mode *pmode; | |
1926 | int *punsignedp, *pvolatilep; | |
1927 | tree *pmask; | |
1928 | { | |
1929 | tree mask = 0; | |
1930 | tree inner; | |
1931 | ||
1932 | STRIP_NOPS (exp); | |
1933 | ||
1934 | if (TREE_CODE (exp) == BIT_AND_EXPR) | |
1935 | { | |
1936 | mask = TREE_OPERAND (exp, 1); | |
1937 | exp = TREE_OPERAND (exp, 0); | |
1938 | STRIP_NOPS (exp); STRIP_NOPS (mask); | |
1939 | if (TREE_CODE (mask) != INTEGER_CST) | |
1940 | return 0; | |
1941 | } | |
1942 | ||
1943 | if (TREE_CODE (exp) != COMPONENT_REF && TREE_CODE (exp) != ARRAY_REF | |
1944 | && TREE_CODE (exp) != BIT_FIELD_REF) | |
1945 | return 0; | |
1946 | ||
1947 | inner = get_inner_reference (exp, pbitsize, pbitpos, pmode, | |
1948 | punsignedp, pvolatilep); | |
1949 | ||
1950 | if (mask == 0) | |
1951 | { | |
1952 | tree unsigned_type = type_for_size (*pbitsize, 1); | |
1953 | int precision = TYPE_PRECISION (unsigned_type); | |
1954 | ||
1955 | mask = convert (unsigned_type, build_int_2 (~0, ~0)); | |
1956 | mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize)); | |
1957 | mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize)); | |
1958 | } | |
1959 | ||
1960 | *pmask = mask; | |
1961 | return inner; | |
1962 | } | |
1963 | ||
1964 | /* Return non-zero if MASK respresents a mask of SIZE ones in the low-order | |
1965 | bit positions. */ | |
1966 | ||
1967 | static int | |
1968 | all_ones_mask_p (mask, size) | |
1969 | tree mask; | |
1970 | int size; | |
1971 | { | |
1972 | tree type = TREE_TYPE (mask); | |
1973 | int precision = TYPE_PRECISION (type); | |
1974 | ||
1975 | return | |
1976 | operand_equal_p (mask, | |
1977 | const_binop (RSHIFT_EXPR, | |
1978 | const_binop (LSHIFT_EXPR, | |
1979 | convert (signed_type (type), | |
1980 | build_int_2 (~0, ~0)), | |
1981 | size_int (precision - size)), | |
1982 | size_int (precision - size)), 0); | |
1983 | } | |
1984 | \f | |
1985 | /* Try to merge two comparisons to the same innermost item. | |
1986 | ||
1987 | For example, if we have p->a == 2 && p->b == 4 and we can make an | |
1988 | object large enough to span both A and B, we can do this with a comparison | |
1989 | against the object ANDed with the a mask. | |
1990 | ||
1991 | If we have p->a == q->a && p->b == q->b, we may be able to use bit masking | |
1992 | operations to do this with one comparison. | |
1993 | ||
1994 | We check for both normal comparisons and the BIT_AND_EXPRs made this by | |
1995 | function and the one above. | |
1996 | ||
1997 | CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR, | |
1998 | TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR. | |
1999 | ||
2000 | TRUTH_TYPE is the type of the logical operand and LHS and RHS are its | |
2001 | two operands. | |
2002 | ||
2003 | We return the simplified tree or 0 if no optimization is possible. */ | |
2004 | ||
2005 | static tree | |
2006 | merge_component_references (code, truth_type, lhs, rhs) | |
2007 | enum tree_code code; | |
2008 | tree truth_type, lhs, rhs; | |
2009 | { | |
2010 | /* If this is the "or" of two comparisons, we can do something if we | |
2011 | the comparisons are NE_EXPR. If this is the "and", we can do something | |
2012 | if the comparisons are EQ_EXPR. I.e., | |
2013 | (a->b == 2 && a->c == 4) can become (a->new == NEW). | |
2014 | ||
2015 | WANTED_CODE is this operation code. For single bit fields, we can | |
2016 | convert EQ_EXPR to NE_EXPR so we need not reject the "wrong" | |
2017 | comparison for one-bit fields. */ | |
2018 | ||
2019 | enum tree_code wanted_code | |
2020 | = (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR) ? EQ_EXPR : NE_EXPR; | |
2021 | enum tree_code lcode, rcode; | |
2022 | tree ll_inner, lr_inner, rl_inner, rr_inner; | |
2023 | int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos; | |
2024 | int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos; | |
2025 | int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos; | |
2026 | int lnbitsize, lnbitpos, rnbitsize, rnbitpos; | |
2027 | int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp; | |
2028 | enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode; | |
2029 | enum machine_mode lnmode, rnmode; | |
2030 | tree ll_mask, lr_mask, rl_mask, rr_mask; | |
2031 | tree l_const = 0, r_const = 0; | |
2032 | tree type, result; | |
2033 | int first_bit, end_bit; | |
2034 | int volatilep = 0; | |
2035 | ||
2036 | /* Start by getting the comparison codes and seeing if we may be able | |
2037 | to do something. Then get all the parameters for each side. Fail | |
2038 | if anything is volatile. */ | |
2039 | ||
2040 | lcode = TREE_CODE (lhs); | |
2041 | rcode = TREE_CODE (rhs); | |
2042 | if ((lcode != EQ_EXPR && lcode != NE_EXPR) | |
2043 | || (rcode != EQ_EXPR && rcode != NE_EXPR) | |
2044 | || TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs)) | |
2045 | return 0; | |
2046 | ||
2047 | ll_inner = decode_field_reference (TREE_OPERAND (lhs, 0), | |
2048 | &ll_bitsize, &ll_bitpos, &ll_mode, | |
2049 | &ll_unsignedp, &volatilep, &ll_mask); | |
2050 | lr_inner = decode_field_reference (TREE_OPERAND (lhs, 1), | |
2051 | &lr_bitsize, &lr_bitpos, &lr_mode, | |
2052 | &lr_unsignedp, &volatilep, &lr_mask); | |
2053 | rl_inner = decode_field_reference (TREE_OPERAND (rhs, 0), | |
2054 | &rl_bitsize, &rl_bitpos, &rl_mode, | |
2055 | &rl_unsignedp, &volatilep, &rl_mask); | |
2056 | rr_inner = decode_field_reference (TREE_OPERAND (rhs, 1), | |
2057 | &rr_bitsize, &rr_bitpos, &rr_mode, | |
2058 | &rr_unsignedp, &volatilep, &rr_mask); | |
2059 | ||
2060 | /* It must be true that the inner operation on the lhs of each | |
2061 | comparison must be the same if we are to be able to do anything. | |
2062 | Then see if we have constants. If not, the same must be true for | |
2063 | the rhs's. */ | |
2064 | if (volatilep || ll_inner == 0 || rl_inner == 0 | |
2065 | || ! operand_equal_p (ll_inner, rl_inner, 0)) | |
2066 | return 0; | |
2067 | ||
2068 | if (TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
2069 | && TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST) | |
2070 | l_const = TREE_OPERAND (lhs, 1), r_const = TREE_OPERAND (rhs, 1); | |
2071 | else if (lr_inner == 0 || rr_inner == 0 | |
2072 | || ! operand_equal_p (lr_inner, rr_inner, 0)) | |
2073 | return 0; | |
2074 | ||
2075 | /* If either comparison code is not correct for our logical operation, | |
2076 | fail. However, we can convert a one-bit comparison against zero into | |
2077 | the opposite comparison against that bit being set in the field. */ | |
2078 | if (lcode != wanted_code) | |
2079 | { | |
2080 | if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask)) | |
2081 | l_const = ll_mask; | |
2082 | else | |
2083 | return 0; | |
2084 | } | |
2085 | ||
2086 | if (rcode != wanted_code) | |
2087 | { | |
2088 | if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask)) | |
2089 | r_const = rl_mask; | |
2090 | else | |
2091 | return 0; | |
2092 | } | |
2093 | ||
2094 | /* See if we can find a mode that contains both fields being compared on | |
2095 | the left. If we can't, fail. Otherwise, update all constants and masks | |
2096 | to be relative to a field of that size. */ | |
2097 | first_bit = MIN (ll_bitpos, rl_bitpos); | |
2098 | end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); | |
2099 | lnmode = get_best_mode (end_bit - first_bit, first_bit, | |
2100 | TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, | |
2101 | volatilep); | |
2102 | if (lnmode == VOIDmode) | |
2103 | return 0; | |
2104 | ||
2105 | lnbitsize = GET_MODE_BITSIZE (lnmode); | |
2106 | lnbitpos = first_bit & ~ (lnbitsize - 1); | |
2107 | type = type_for_size (lnbitsize, 1); | |
2108 | xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos; | |
2109 | ||
2110 | #if BYTES_BIG_ENDIAN | |
2111 | xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize; | |
2112 | xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize; | |
2113 | #endif | |
2114 | ||
2115 | ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask), | |
2116 | size_int (xll_bitpos)); | |
2117 | rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask), | |
2118 | size_int (xrl_bitpos)); | |
2119 | ||
2120 | /* Make sure the constants are interpreted as unsigned, so we | |
2121 | don't have sign bits outside the range of their type. */ | |
2122 | ||
2123 | if (l_const) | |
2124 | { | |
2125 | l_const = convert (unsigned_type (TREE_TYPE (l_const)), l_const); | |
2126 | l_const = const_binop (LSHIFT_EXPR, convert (type, l_const), | |
2127 | size_int (xll_bitpos)); | |
2128 | } | |
2129 | if (r_const) | |
2130 | { | |
2131 | r_const = convert (unsigned_type (TREE_TYPE (r_const)), r_const); | |
2132 | r_const = const_binop (LSHIFT_EXPR, convert (type, r_const), | |
2133 | size_int (xrl_bitpos)); | |
2134 | } | |
2135 | ||
2136 | /* If the right sides are not constant, do the same for it. Also, | |
2137 | disallow this optimization if a size or signedness mismatch occurs | |
2138 | between the left and right sides. */ | |
2139 | if (l_const == 0) | |
2140 | { | |
2141 | if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize | |
2142 | || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp) | |
2143 | return 0; | |
2144 | ||
2145 | first_bit = MIN (lr_bitpos, rr_bitpos); | |
2146 | end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); | |
2147 | rnmode = get_best_mode (end_bit - first_bit, first_bit, | |
2148 | TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, | |
2149 | volatilep); | |
2150 | if (rnmode == VOIDmode) | |
2151 | return 0; | |
2152 | ||
2153 | rnbitsize = GET_MODE_BITSIZE (rnmode); | |
2154 | rnbitpos = first_bit & ~ (rnbitsize - 1); | |
2155 | xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos; | |
2156 | ||
2157 | #if BYTES_BIG_ENDIAN | |
2158 | xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize; | |
2159 | xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize; | |
2160 | #endif | |
2161 | ||
2162 | lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask), | |
2163 | size_int (xlr_bitpos)); | |
2164 | rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask), | |
2165 | size_int (xrr_bitpos)); | |
2166 | ||
2167 | /* Make a mask that corresponds to both fields being compared. | |
2168 | Do this for both items being compared. If the masks agree, | |
2169 | we can do this by masking both and comparing the masked | |
2170 | results. */ | |
2171 | ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask); | |
2172 | lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask); | |
2173 | if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize) | |
2174 | { | |
2175 | lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, | |
2176 | ll_unsignedp || rl_unsignedp); | |
2177 | rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos, | |
2178 | lr_unsignedp || rr_unsignedp); | |
2179 | if (! all_ones_mask_p (ll_mask, lnbitsize)) | |
2180 | { | |
2181 | lhs = build (BIT_AND_EXPR, type, lhs, ll_mask); | |
2182 | rhs = build (BIT_AND_EXPR, type, rhs, ll_mask); | |
2183 | } | |
2184 | return build (wanted_code, truth_type, lhs, rhs); | |
2185 | } | |
2186 | ||
2187 | /* There is still another way we can do something: If both pairs of | |
2188 | fields being compared are adjacent, we may be able to make a wider | |
2189 | field containing them both. */ | |
2190 | if ((ll_bitsize + ll_bitpos == rl_bitpos | |
2191 | && lr_bitsize + lr_bitpos == rr_bitpos) | |
2192 | || (ll_bitpos == rl_bitpos + rl_bitsize | |
2193 | && lr_bitpos == rr_bitpos + rr_bitsize)) | |
2194 | return build (wanted_code, truth_type, | |
2195 | make_bit_field_ref (ll_inner, type, | |
2196 | ll_bitsize + rl_bitsize, | |
2197 | MIN (ll_bitpos, rl_bitpos), | |
2198 | ll_unsignedp), | |
2199 | make_bit_field_ref (lr_inner, type, | |
2200 | lr_bitsize + rr_bitsize, | |
2201 | MIN (lr_bitpos, rr_bitpos), | |
2202 | lr_unsignedp)); | |
2203 | ||
2204 | return 0; | |
2205 | } | |
2206 | ||
2207 | /* Handle the case of comparisons with constants. If there is something in | |
2208 | common between the masks, those bits of the constants must be the same. | |
2209 | If not, the condition is always false. Test for this to avoid generating | |
2210 | incorrect code below. */ | |
2211 | result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask); | |
2212 | if (! integer_zerop (result) | |
2213 | && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const), | |
2214 | const_binop (BIT_AND_EXPR, result, r_const)) != 1) | |
2215 | { | |
2216 | if (wanted_code == NE_EXPR) | |
2217 | { | |
2218 | warning ("`or' of unmatched not-equal tests is always 1"); | |
2219 | return convert (truth_type, integer_one_node); | |
2220 | } | |
2221 | else | |
2222 | { | |
2223 | warning ("`and' of mutually exclusive equal-tests is always zero"); | |
2224 | return convert (truth_type, integer_zero_node); | |
2225 | } | |
2226 | } | |
2227 | ||
2228 | /* Construct the expression we will return. First get the component | |
2229 | reference we will make. Unless the mask is all ones the width of | |
2230 | that field, perform the mask operation. Then compare with the | |
2231 | merged constant. */ | |
2232 | result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, | |
2233 | ll_unsignedp || rl_unsignedp); | |
2234 | ||
2235 | ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask); | |
2236 | if (! all_ones_mask_p (ll_mask, lnbitsize)) | |
2237 | result = build (BIT_AND_EXPR, type, result, ll_mask); | |
2238 | ||
2239 | return build (wanted_code, truth_type, result, | |
2240 | const_binop (BIT_IOR_EXPR, l_const, r_const)); | |
2241 | } | |
2242 | \f | |
2243 | /* Perform constant folding and related simplification of EXPR. | |
2244 | The related simplifications include x*1 => x, x*0 => 0, etc., | |
2245 | and application of the associative law. | |
2246 | NOP_EXPR conversions may be removed freely (as long as we | |
2247 | are careful not to change the C type of the overall expression) | |
2248 | We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR, | |
2249 | but we can constant-fold them if they have constant operands. */ | |
2250 | ||
2251 | tree | |
2252 | fold (expr) | |
2253 | tree expr; | |
2254 | { | |
2255 | register tree t = expr; | |
2256 | tree t1 = NULL_TREE; | |
2257 | tree type = TREE_TYPE (expr); | |
2258 | register tree arg0, arg1; | |
2259 | register enum tree_code code = TREE_CODE (t); | |
2260 | register int kind; | |
2261 | ||
2262 | /* WINS will be nonzero when the switch is done | |
2263 | if all operands are constant. */ | |
2264 | ||
2265 | int wins = 1; | |
2266 | ||
2267 | /* Return right away if already constant. */ | |
2268 | if (TREE_CONSTANT (t)) | |
2269 | { | |
2270 | if (code == CONST_DECL) | |
2271 | return DECL_INITIAL (t); | |
2272 | return t; | |
2273 | } | |
2274 | ||
2275 | kind = TREE_CODE_CLASS (code); | |
2276 | if (kind == 'e' || kind == '<' || kind == '1' || kind == '2' || kind == 'r') | |
2277 | { | |
2278 | register int len = tree_code_length[(int) code]; | |
2279 | register int i; | |
2280 | for (i = 0; i < len; i++) | |
2281 | { | |
2282 | tree op = TREE_OPERAND (t, i); | |
2283 | ||
2284 | if (op == 0) | |
2285 | continue; /* Valid for CALL_EXPR, at least. */ | |
2286 | ||
2287 | /* Strip any conversions that don't change the mode. */ | |
2288 | STRIP_NOPS (op); | |
2289 | ||
2290 | if (TREE_CODE (op) != INTEGER_CST | |
2291 | #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) | |
2292 | && TREE_CODE (op) != REAL_CST | |
2293 | #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ | |
2294 | ) | |
2295 | /* Note that TREE_CONSTANT isn't enough: | |
2296 | static var addresses are constant but we can't | |
2297 | do arithmetic on them. */ | |
2298 | wins = 0; | |
2299 | ||
2300 | if (i == 0) | |
2301 | arg0 = op; | |
2302 | else if (i == 1) | |
2303 | arg1 = op; | |
2304 | } | |
2305 | } | |
2306 | ||
2307 | /* If this is a commutative operation, and ARG0 is a constant, move it | |
2308 | to ARG1 to reduce the number of tests below. */ | |
2309 | if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR | |
2310 | || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR | |
2311 | || code == BIT_AND_EXPR) | |
2312 | && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST)) | |
2313 | { | |
2314 | tree tem = arg0; | |
2315 | arg0 = arg1; arg1 = tem; | |
2316 | ||
2317 | TREE_OPERAND (t, 0) = arg0; | |
2318 | TREE_OPERAND (t, 1) = arg1; | |
2319 | } | |
2320 | ||
2321 | /* Now WINS is set as described above, | |
2322 | ARG0 is the first operand of EXPR, | |
2323 | and ARG1 is the second operand (if it has more than one operand). | |
2324 | ||
2325 | First check for cases where an arithmetic operation is applied to a | |
2326 | compound, conditional, or comparison operation. Push the arithmetic | |
2327 | operation inside the compound or conditional to see if any folding | |
2328 | can then be done. Convert comparison to conditional for this purpose. | |
2329 | The also optimizes non-constant cases that used to be done in | |
2330 | expand_expr. */ | |
2331 | if (TREE_CODE_CLASS (code) == '1') | |
2332 | { | |
2333 | if (TREE_CODE (arg0) == COMPOUND_EXPR) | |
2334 | return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), | |
2335 | fold (build1 (code, type, TREE_OPERAND (arg0, 1)))); | |
2336 | else if (TREE_CODE (arg0) == COND_EXPR) | |
2337 | return fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0), | |
2338 | fold (build1 (code, type, TREE_OPERAND (arg0, 1))), | |
2339 | fold (build1 (code, type, TREE_OPERAND (arg0, 2))))); | |
2340 | else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<') | |
2341 | return fold (build (COND_EXPR, type, arg0, | |
2342 | fold (build1 (code, type, integer_one_node)), | |
2343 | fold (build1 (code, type, integer_zero_node)))); | |
2344 | } | |
2345 | else if (TREE_CODE_CLASS (code) == '2') | |
2346 | { | |
2347 | if (TREE_CODE (arg1) == COMPOUND_EXPR) | |
2348 | return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), | |
2349 | fold (build (code, type, arg0, TREE_OPERAND (arg1, 1)))); | |
2350 | else if (TREE_CODE (arg1) == COND_EXPR | |
2351 | || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<') | |
2352 | { | |
2353 | tree test, true_value, false_value; | |
2354 | ||
2355 | if (TREE_CODE (arg1) == COND_EXPR) | |
2356 | { | |
2357 | test = TREE_OPERAND (arg1, 0); | |
2358 | true_value = TREE_OPERAND (arg1, 1); | |
2359 | false_value = TREE_OPERAND (arg1, 2); | |
2360 | } | |
2361 | else | |
2362 | { | |
2363 | test = arg1; | |
2364 | true_value = integer_one_node; | |
2365 | false_value = integer_zero_node; | |
2366 | } | |
2367 | ||
2368 | if (TREE_CODE (arg0) != VAR_DECL && TREE_CODE (arg0) != PARM_DECL) | |
2369 | arg0 = save_expr (arg0); | |
2370 | test = fold (build (COND_EXPR, type, test, | |
2371 | fold (build (code, type, arg0, true_value)), | |
2372 | fold (build (code, type, arg0, false_value)))); | |
2373 | if (TREE_CODE (arg0) == SAVE_EXPR) | |
2374 | return build (COMPOUND_EXPR, type, | |
2375 | convert (void_type_node, arg0), test); | |
2376 | else | |
2377 | return convert (type, test); | |
2378 | } | |
2379 | ||
2380 | else if (TREE_CODE (arg0) == COMPOUND_EXPR) | |
2381 | return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), | |
2382 | fold (build (code, type, TREE_OPERAND (arg0, 1), arg1))); | |
2383 | else if (TREE_CODE (arg0) == COND_EXPR | |
2384 | || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<') | |
2385 | { | |
2386 | tree test, true_value, false_value; | |
2387 | ||
2388 | if (TREE_CODE (arg0) == COND_EXPR) | |
2389 | { | |
2390 | test = TREE_OPERAND (arg0, 0); | |
2391 | true_value = TREE_OPERAND (arg0, 1); | |
2392 | false_value = TREE_OPERAND (arg0, 2); | |
2393 | } | |
2394 | else | |
2395 | { | |
2396 | test = arg0; | |
2397 | true_value = integer_one_node; | |
2398 | false_value = integer_zero_node; | |
2399 | } | |
2400 | ||
2401 | if (TREE_CODE (arg1) != VAR_DECL && TREE_CODE (arg1) != PARM_DECL) | |
2402 | arg1 = save_expr (arg1); | |
2403 | test = fold (build (COND_EXPR, type, test, | |
2404 | fold (build (code, type, true_value, arg1)), | |
2405 | fold (build (code, type, false_value, arg1)))); | |
2406 | if (TREE_CODE (arg1) == SAVE_EXPR) | |
2407 | return build (COMPOUND_EXPR, type, | |
2408 | convert (void_type_node, arg1), test); | |
2409 | else | |
2410 | return convert (type, test); | |
2411 | } | |
2412 | } | |
2413 | ||
2414 | switch (code) | |
2415 | { | |
2416 | case INTEGER_CST: | |
2417 | case REAL_CST: | |
2418 | case STRING_CST: | |
2419 | case COMPLEX_CST: | |
2420 | case CONSTRUCTOR: | |
2421 | return t; | |
2422 | ||
2423 | case CONST_DECL: | |
2424 | return fold (DECL_INITIAL (t)); | |
2425 | ||
2426 | case NOP_EXPR: | |
2427 | case FLOAT_EXPR: | |
2428 | case CONVERT_EXPR: | |
2429 | case FIX_TRUNC_EXPR: | |
2430 | /* Other kinds of FIX are not handled properly by fold_convert. */ | |
2431 | /* Two conversions in a row are not needed unless: | |
2432 | - the intermediate type is narrower than both initial and final, or | |
2433 | - the initial type is a pointer type and the precisions of the | |
2434 | intermediate and final types differ, or | |
2435 | - the final type is a pointer type and the precisions of the | |
2436 | initial and intermediate types differ. */ | |
2437 | if ((TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR | |
2438 | || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR) | |
2439 | && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) | |
2440 | > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) | |
2441 | || | |
2442 | TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) | |
2443 | > TYPE_PRECISION (TREE_TYPE (t))) | |
2444 | && ((TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0))) | |
2445 | && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) | |
2446 | > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))))) | |
2447 | == | |
2448 | (TREE_UNSIGNED (TREE_TYPE (t)) | |
2449 | && (TYPE_PRECISION (TREE_TYPE (t)) | |
2450 | > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))))) | |
2451 | && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) | |
2452 | == POINTER_TYPE) | |
2453 | && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))) | |
2454 | != TYPE_PRECISION (TREE_TYPE (t)))) | |
2455 | && ! (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE | |
2456 | && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0))) | |
2457 | != TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))))) | |
2458 | return convert (TREE_TYPE (t), TREE_OPERAND (TREE_OPERAND (t, 0), 0)); | |
2459 | ||
2460 | if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR | |
2461 | && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))) | |
2462 | { | |
2463 | /* Don't leave an assignment inside a conversion. */ | |
2464 | tree prev = TREE_OPERAND (t, 0); | |
2465 | TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1); | |
2466 | /* First do the assignment, then return converted constant. */ | |
2467 | t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t)); | |
2468 | TREE_USED (t) = 1; | |
2469 | return t; | |
2470 | } | |
2471 | if (!wins) | |
2472 | { | |
2473 | TREE_CONSTANT (t) = TREE_CONSTANT (arg0); | |
2474 | return t; | |
2475 | } | |
2476 | return fold_convert (t, arg0); | |
2477 | ||
2478 | #if 0 /* This loses on &"foo"[0]. */ | |
2479 | case ARRAY_REF: | |
2480 | { | |
2481 | int i; | |
2482 | ||
2483 | /* Fold an expression like: "foo"[2] */ | |
2484 | if (TREE_CODE (arg0) == STRING_CST | |
2485 | && TREE_CODE (arg1) == INTEGER_CST | |
2486 | && !TREE_INT_CST_HIGH (arg1) | |
2487 | && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0)) | |
2488 | { | |
2489 | t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0); | |
2490 | TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0)); | |
2491 | force_fit_type (t); | |
2492 | } | |
2493 | } | |
2494 | return t; | |
2495 | #endif /* 0 */ | |
2496 | ||
2497 | case RANGE_EXPR: | |
2498 | TREE_CONSTANT (t) = wins; | |
2499 | return t; | |
2500 | ||
2501 | case NEGATE_EXPR: | |
2502 | if (wins) | |
2503 | { | |
2504 | if (TREE_CODE (arg0) == INTEGER_CST) | |
2505 | { | |
2506 | if (TREE_INT_CST_LOW (arg0) == 0) | |
2507 | t = build_int_2 (0, - TREE_INT_CST_HIGH (arg0)); | |
2508 | else | |
2509 | t = build_int_2 (- TREE_INT_CST_LOW (arg0), | |
2510 | ~ TREE_INT_CST_HIGH (arg0)); | |
2511 | TREE_TYPE (t) = type; | |
2512 | force_fit_type (t); | |
2513 | } | |
2514 | else if (TREE_CODE (arg0) == REAL_CST) | |
2515 | t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); | |
2516 | TREE_TYPE (t) = type; | |
2517 | } | |
2518 | else if (TREE_CODE (arg0) == NEGATE_EXPR) | |
2519 | return TREE_OPERAND (arg0, 0); | |
2520 | ||
2521 | /* Convert - (a - b) to (b - a) for non-floating-point. */ | |
2522 | else if (TREE_CODE (arg0) == MINUS_EXPR && TREE_CODE (type) != REAL_TYPE) | |
2523 | return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1), | |
2524 | TREE_OPERAND (arg0, 0)); | |
2525 | ||
2526 | return t; | |
2527 | ||
2528 | case ABS_EXPR: | |
2529 | if (wins) | |
2530 | { | |
2531 | if (TREE_CODE (arg0) == INTEGER_CST) | |
2532 | { | |
2533 | if (! TREE_UNSIGNED (type) | |
2534 | && TREE_INT_CST_HIGH (arg0) < 0) | |
2535 | { | |
2536 | if (TREE_INT_CST_LOW (arg0) == 0) | |
2537 | t = build_int_2 (0, - TREE_INT_CST_HIGH (arg0)); | |
2538 | else | |
2539 | t = build_int_2 (- TREE_INT_CST_LOW (arg0), | |
2540 | ~ TREE_INT_CST_HIGH (arg0)); | |
2541 | } | |
2542 | } | |
2543 | else if (TREE_CODE (arg0) == REAL_CST) | |
2544 | { | |
2545 | if (REAL_VALUES_LESS (TREE_REAL_CST (arg0), dconst0)) | |
2546 | t = build_real (type, | |
2547 | REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); | |
2548 | } | |
2549 | TREE_TYPE (t) = type; | |
2550 | } | |
2551 | else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR) | |
2552 | return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0)); | |
2553 | return t; | |
2554 | ||
2555 | case BIT_NOT_EXPR: | |
2556 | if (wins) | |
2557 | { | |
2558 | if (TREE_CODE (arg0) == INTEGER_CST) | |
2559 | t = build_int_2 (~ TREE_INT_CST_LOW (arg0), | |
2560 | ~ TREE_INT_CST_HIGH (arg0)); | |
2561 | TREE_TYPE (t) = type; | |
2562 | force_fit_type (t); | |
2563 | } | |
2564 | else if (TREE_CODE (arg0) == BIT_NOT_EXPR) | |
2565 | return TREE_OPERAND (arg0, 0); | |
2566 | return t; | |
2567 | ||
2568 | case PLUS_EXPR: | |
2569 | /* A + (-B) -> A - B */ | |
2570 | if (TREE_CODE (arg1) == NEGATE_EXPR) | |
2571 | return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); | |
2572 | else if (TREE_CODE (type) != REAL_TYPE) | |
2573 | { | |
2574 | if (integer_zerop (arg1)) | |
2575 | return non_lvalue (convert (type, arg0)); | |
2576 | ||
2577 | /* If we are adding two BIT_AND_EXPR's, both of which are and'ing | |
2578 | with a constant, and the two constants have no bits in common, | |
2579 | we should treat this as a BIT_IOR_EXPR since this may produce more | |
2580 | simplifications. */ | |
2581 | if (TREE_CODE (arg0) == BIT_AND_EXPR | |
2582 | && TREE_CODE (arg1) == BIT_AND_EXPR | |
2583 | && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST | |
2584 | && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST | |
2585 | && integer_zerop (const_binop (BIT_AND_EXPR, | |
2586 | TREE_OPERAND (arg0, 1), | |
2587 | TREE_OPERAND (arg1, 1)))) | |
2588 | { | |
2589 | code = BIT_IOR_EXPR; | |
2590 | goto bit_ior; | |
2591 | } | |
2592 | } | |
2593 | /* In IEEE floating point, x+0 may not equal x. */ | |
2594 | else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT | |
2595 | && real_zerop (arg1)) | |
2596 | return non_lvalue (convert (type, arg0)); | |
2597 | associate: | |
2598 | /* In most languages, can't associate operations on floats | |
2599 | through parentheses. Rather than remember where the parentheses | |
2600 | were, we don't associate floats at all. It shouldn't matter much. */ | |
2601 | if (TREE_CODE (type) == REAL_TYPE) | |
2602 | goto binary; | |
2603 | /* The varsign == -1 cases happen only for addition and subtraction. | |
2604 | It says that the arg that was split was really CON minus VAR. | |
2605 | The rest of the code applies to all associative operations. */ | |
2606 | if (!wins) | |
2607 | { | |
2608 | tree var, con, tem; | |
2609 | int varsign; | |
2610 | ||
2611 | if (split_tree (arg0, code, &var, &con, &varsign)) | |
2612 | { | |
2613 | if (varsign == -1) | |
2614 | { | |
2615 | /* EXPR is (CON-VAR) +- ARG1. */ | |
2616 | /* If it is + and VAR==ARG1, return just CONST. */ | |
2617 | if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0)) | |
2618 | return convert (TREE_TYPE (t), con); | |
2619 | ||
2620 | /* Otherwise return (CON +- ARG1) - VAR. */ | |
2621 | TREE_SET_CODE (t, MINUS_EXPR); | |
2622 | TREE_OPERAND (t, 1) = var; | |
2623 | TREE_OPERAND (t, 0) | |
2624 | = fold (build (code, TREE_TYPE (t), con, arg1)); | |
2625 | } | |
2626 | else | |
2627 | { | |
2628 | /* EXPR is (VAR+CON) +- ARG1. */ | |
2629 | /* If it is - and VAR==ARG1, return just CONST. */ | |
2630 | if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0)) | |
2631 | return convert (TREE_TYPE (t), con); | |
2632 | ||
2633 | /* Otherwise return VAR +- (ARG1 +- CON). */ | |
2634 | TREE_OPERAND (t, 1) = tem | |
2635 | = fold (build (code, TREE_TYPE (t), arg1, con)); | |
2636 | TREE_OPERAND (t, 0) = var; | |
2637 | if (integer_zerop (tem) | |
2638 | && (code == PLUS_EXPR || code == MINUS_EXPR)) | |
2639 | return convert (type, var); | |
2640 | /* If we have x +/- (c - d) [c an explicit integer] | |
2641 | change it to x -/+ (d - c) since if d is relocatable | |
2642 | then the latter can be a single immediate insn | |
2643 | and the former cannot. */ | |
2644 | if (TREE_CODE (tem) == MINUS_EXPR | |
2645 | && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST) | |
2646 | { | |
2647 | tree tem1 = TREE_OPERAND (tem, 1); | |
2648 | TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0); | |
2649 | TREE_OPERAND (tem, 0) = tem1; | |
2650 | TREE_SET_CODE (t, | |
2651 | (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); | |
2652 | } | |
2653 | } | |
2654 | return t; | |
2655 | } | |
2656 | ||
2657 | if (split_tree (arg1, code, &var, &con, &varsign)) | |
2658 | { | |
2659 | /* EXPR is ARG0 +- (CON +- VAR). */ | |
2660 | if (varsign == -1) | |
2661 | TREE_SET_CODE (t, | |
2662 | (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); | |
2663 | if (TREE_CODE (t) == MINUS_EXPR | |
2664 | && operand_equal_p (var, arg0, 0)) | |
2665 | { | |
2666 | /* If VAR and ARG0 cancel, return just CON or -CON. */ | |
2667 | if (code == PLUS_EXPR) | |
2668 | return convert (TREE_TYPE (t), con); | |
2669 | return fold (build1 (NEGATE_EXPR, TREE_TYPE (t), | |
2670 | convert (TREE_TYPE (t), con))); | |
2671 | } | |
2672 | TREE_OPERAND (t, 0) | |
2673 | = fold (build (code, TREE_TYPE (t), arg0, con)); | |
2674 | TREE_OPERAND (t, 1) = var; | |
2675 | if (integer_zerop (TREE_OPERAND (t, 0)) | |
2676 | && TREE_CODE (t) == PLUS_EXPR) | |
2677 | return convert (TREE_TYPE (t), var); | |
2678 | return t; | |
2679 | } | |
2680 | } | |
2681 | binary: | |
2682 | #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC) | |
2683 | if (TREE_CODE (arg1) == REAL_CST) | |
2684 | return t; | |
2685 | #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */ | |
2686 | if (wins) | |
2687 | t1 = const_binop (code, arg0, arg1); | |
2688 | if (t1 != NULL_TREE) | |
2689 | { | |
2690 | /* The return value should always have | |
2691 | the same type as the original expression. */ | |
2692 | TREE_TYPE (t1) = TREE_TYPE (t); | |
2693 | return t1; | |
2694 | } | |
2695 | return t; | |
2696 | ||
2697 | case MINUS_EXPR: | |
2698 | if (TREE_CODE (type) != REAL_TYPE) | |
2699 | { | |
2700 | if (! wins && integer_zerop (arg0)) | |
2701 | return build1 (NEGATE_EXPR, type, arg1); | |
2702 | if (integer_zerop (arg1)) | |
2703 | return non_lvalue (convert (type, arg0)); | |
2704 | } | |
2705 | /* Convert A - (-B) to A + B. */ | |
2706 | else if (TREE_CODE (arg1) == NEGATE_EXPR) | |
2707 | return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); | |
2708 | else | |
2709 | { | |
2710 | if (! wins && real_zerop (arg0)) | |
2711 | return build1 (NEGATE_EXPR, type, arg1); | |
2712 | /* In IEEE floating point, x-0 may not equal x. */ | |
2713 | if (real_zerop (arg1) && TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT) | |
2714 | return non_lvalue (convert (type, arg0)); | |
2715 | } | |
2716 | /* Fold &x - &x. This can happen from &x.foo - &x. | |
2717 | Note that can't be done for certain floats even in non-IEEE formats. | |
2718 | Also note that operand_equal_p is always false is an operand | |
2719 | is volatile. */ | |
2720 | ||
2721 | if (operand_equal_p (arg0, arg1, | |
2722 | TREE_CODE (type) == REAL_TYPE)) | |
2723 | return convert (type, integer_zero_node); | |
2724 | goto associate; | |
2725 | ||
2726 | case MULT_EXPR: | |
2727 | if (TREE_CODE (type) != REAL_TYPE) | |
2728 | { | |
2729 | if (integer_zerop (arg1)) | |
2730 | return omit_one_operand (type, arg1, arg0); | |
2731 | if (integer_onep (arg1)) | |
2732 | return non_lvalue (convert (type, arg0)); | |
2733 | ||
2734 | /* (a * (1 << b)) is (a << b) */ | |
2735 | if (TREE_CODE (arg1) == LSHIFT_EXPR | |
2736 | && integer_onep (TREE_OPERAND (arg1, 0))) | |
2737 | return fold (build (LSHIFT_EXPR, type, arg0, | |
2738 | TREE_OPERAND (arg1, 1))); | |
2739 | if (TREE_CODE (arg0) == LSHIFT_EXPR | |
2740 | && integer_onep (TREE_OPERAND (arg0, 0))) | |
2741 | return fold (build (LSHIFT_EXPR, type, arg1, | |
2742 | TREE_OPERAND (arg0, 1))); | |
2743 | } | |
2744 | /* In IEEE floating point, these optimizations are not correct. */ | |
2745 | else | |
2746 | { | |
2747 | if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT | |
2748 | && real_zerop (arg1)) | |
2749 | return omit_one_operand (type, arg1, arg0); | |
2750 | /* In IEEE floating point, x*1 is not equivalent to x for nans. | |
2751 | However, ANSI says we can drop signals, | |
2752 | so we can do this anyway. */ | |
2753 | if (real_onep (arg1)) | |
2754 | return non_lvalue (convert (type, arg0)); | |
2755 | /* x*2 is x+x */ | |
2756 | if (! wins && real_twop (arg1)) | |
2757 | { | |
2758 | tree arg = save_expr (arg0); | |
2759 | return build (PLUS_EXPR, type, arg, arg); | |
2760 | } | |
2761 | } | |
2762 | goto associate; | |
2763 | ||
2764 | case BIT_IOR_EXPR: | |
2765 | bit_ior: | |
2766 | if (integer_all_onesp (arg1)) | |
2767 | return omit_one_operand (type, arg1, arg0); | |
2768 | if (integer_zerop (arg1)) | |
2769 | return non_lvalue (convert (type, arg0)); | |
2770 | t1 = distribute_bit_expr (code, type, arg0, arg1); | |
2771 | if (t1 != NULL_TREE) | |
2772 | return t1; | |
2773 | goto associate; | |
2774 | ||
2775 | case BIT_XOR_EXPR: | |
2776 | if (integer_zerop (arg1)) | |
2777 | return non_lvalue (convert (type, arg0)); | |
2778 | if (integer_all_onesp (arg1)) | |
2779 | return fold (build1 (BIT_NOT_EXPR, type, arg0)); | |
2780 | goto associate; | |
2781 | ||
2782 | case BIT_AND_EXPR: | |
2783 | bit_and: | |
2784 | if (integer_all_onesp (arg1)) | |
2785 | return non_lvalue (convert (type, arg0)); | |
2786 | if (integer_zerop (arg1)) | |
2787 | return omit_one_operand (type, arg1, arg0); | |
2788 | t1 = distribute_bit_expr (code, type, arg0, arg1); | |
2789 | if (t1 != NULL_TREE) | |
2790 | return t1; | |
2791 | /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */ | |
2792 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR | |
2793 | && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0)))) | |
2794 | { | |
2795 | int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0))); | |
2796 | if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_INT | |
2797 | && (~TREE_INT_CST_LOW (arg0) & ((1 << prec) - 1)) == 0) | |
2798 | return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0)); | |
2799 | } | |
2800 | if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR | |
2801 | && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) | |
2802 | { | |
2803 | int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))); | |
2804 | if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_INT | |
2805 | && (~TREE_INT_CST_LOW (arg1) & ((1 << prec) - 1)) == 0) | |
2806 | return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0)); | |
2807 | } | |
2808 | goto associate; | |
2809 | ||
2810 | case BIT_ANDTC_EXPR: | |
2811 | if (integer_all_onesp (arg0)) | |
2812 | return non_lvalue (convert (type, arg1)); | |
2813 | if (integer_zerop (arg0)) | |
2814 | return omit_one_operand (type, arg0, arg1); | |
2815 | if (TREE_CODE (arg1) == INTEGER_CST) | |
2816 | { | |
2817 | arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1)); | |
2818 | code = BIT_AND_EXPR; | |
2819 | goto bit_and; | |
2820 | } | |
2821 | goto binary; | |
2822 | ||
2823 | case TRUNC_DIV_EXPR: | |
2824 | case ROUND_DIV_EXPR: | |
2825 | case FLOOR_DIV_EXPR: | |
2826 | case CEIL_DIV_EXPR: | |
2827 | case EXACT_DIV_EXPR: | |
2828 | case RDIV_EXPR: | |
2829 | if (integer_onep (arg1)) | |
2830 | return non_lvalue (convert (type, arg0)); | |
2831 | if (integer_zerop (arg1)) | |
2832 | return t; | |
2833 | #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) | |
2834 | #ifndef REAL_INFINITY | |
2835 | if (TREE_CODE (arg1) == REAL_CST | |
2836 | && real_zerop (arg1)) | |
2837 | return t; | |
2838 | #endif | |
2839 | #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ | |
2840 | ||
2841 | goto binary; | |
2842 | ||
2843 | case CEIL_MOD_EXPR: | |
2844 | case FLOOR_MOD_EXPR: | |
2845 | case ROUND_MOD_EXPR: | |
2846 | case TRUNC_MOD_EXPR: | |
2847 | if (integer_onep (arg1)) | |
2848 | return omit_one_operand (type, integer_zero_node, arg0); | |
2849 | if (integer_zerop (arg1)) | |
2850 | return t; | |
2851 | goto binary; | |
2852 | ||
2853 | case LSHIFT_EXPR: | |
2854 | case RSHIFT_EXPR: | |
2855 | case LROTATE_EXPR: | |
2856 | case RROTATE_EXPR: | |
2857 | if (integer_zerop (arg1)) | |
2858 | return non_lvalue (convert (type, arg0)); | |
2859 | /* Since negative shift count is not well-defined, | |
2860 | don't try to compute it in the compiler. */ | |
2861 | if (tree_int_cst_lt (arg1, integer_zero_node)) | |
2862 | return t; | |
2863 | goto binary; | |
2864 | ||
2865 | case MIN_EXPR: | |
2866 | if (operand_equal_p (arg0, arg1, 0)) | |
2867 | return arg0; | |
2868 | if (TREE_CODE (type) == INTEGER_TYPE | |
2869 | && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1)) | |
2870 | return omit_one_operand (type, arg1, arg0); | |
2871 | goto associate; | |
2872 | ||
2873 | case MAX_EXPR: | |
2874 | if (operand_equal_p (arg0, arg1, 0)) | |
2875 | return arg0; | |
2876 | if (TREE_CODE (type) == INTEGER_TYPE | |
2877 | && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1)) | |
2878 | return omit_one_operand (type, arg1, arg0); | |
2879 | goto associate; | |
2880 | ||
2881 | case TRUTH_NOT_EXPR: | |
2882 | /* Note that the operand of this must be an int | |
2883 | and its values must be 0 or 1. | |
2884 | ("true" is a fixed value perhaps depending on the language, | |
2885 | but we don't handle values other than 1 correctly yet.) */ | |
2886 | return invert_truthvalue (arg0); | |
2887 | ||
2888 | case TRUTH_ANDIF_EXPR: | |
2889 | /* Note that the operands of this must be ints | |
2890 | and their values must be 0 or 1. | |
2891 | ("true" is a fixed value perhaps depending on the language.) */ | |
2892 | /* If first arg is constant zero, return it. */ | |
2893 | if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0)) | |
2894 | return arg0; | |
2895 | case TRUTH_AND_EXPR: | |
2896 | /* If either arg is constant true, drop it. */ | |
2897 | if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) | |
2898 | return non_lvalue (arg1); | |
2899 | if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) | |
2900 | return non_lvalue (arg0); | |
2901 | /* Both known to be zero => return zero. */ | |
2902 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
2903 | return arg0; | |
2904 | ||
2905 | truth_andor: | |
2906 | /* Check for the possibility of merging component references. If our | |
2907 | lhs is another similar operation, try to merge its rhs with our | |
2908 | rhs. Then try to merge our lhs and rhs. */ | |
2909 | if (optimize) | |
2910 | { | |
2911 | tree tem; | |
2912 | ||
2913 | if (TREE_CODE (arg0) == code) | |
2914 | { | |
2915 | tem = merge_component_references (code, type, | |
2916 | TREE_OPERAND (arg0, 1), arg1); | |
2917 | if (tem) | |
2918 | return fold (build (code, type, TREE_OPERAND (arg0, 0), tem)); | |
2919 | } | |
2920 | ||
2921 | tem = merge_component_references (code, type, arg0, arg1); | |
2922 | if (tem) | |
2923 | return tem; | |
2924 | } | |
2925 | return t; | |
2926 | ||
2927 | case TRUTH_ORIF_EXPR: | |
2928 | /* Note that the operands of this must be ints | |
2929 | and their values must be 0 or true. | |
2930 | ("true" is a fixed value perhaps depending on the language.) */ | |
2931 | /* If first arg is constant true, return it. */ | |
2932 | if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) | |
2933 | return arg0; | |
2934 | case TRUTH_OR_EXPR: | |
2935 | /* If either arg is constant zero, drop it. */ | |
2936 | if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0)) | |
2937 | return non_lvalue (arg1); | |
2938 | if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)) | |
2939 | return non_lvalue (arg0); | |
2940 | /* Both known to be true => return true. */ | |
2941 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
2942 | return arg0; | |
2943 | goto truth_andor; | |
2944 | ||
2945 | case EQ_EXPR: | |
2946 | case NE_EXPR: | |
2947 | case LT_EXPR: | |
2948 | case GT_EXPR: | |
2949 | case LE_EXPR: | |
2950 | case GE_EXPR: | |
2951 | /* If one arg is a constant integer, put it last. */ | |
2952 | if (TREE_CODE (arg0) == INTEGER_CST | |
2953 | && TREE_CODE (arg1) != INTEGER_CST) | |
2954 | { | |
2955 | TREE_OPERAND (t, 0) = arg1; | |
2956 | TREE_OPERAND (t, 1) = arg0; | |
2957 | arg0 = TREE_OPERAND (t, 0); | |
2958 | arg1 = TREE_OPERAND (t, 1); | |
2959 | switch (code) | |
2960 | { | |
2961 | case GT_EXPR: | |
2962 | code = LT_EXPR; | |
2963 | break; | |
2964 | case GE_EXPR: | |
2965 | code = LE_EXPR; | |
2966 | break; | |
2967 | case LT_EXPR: | |
2968 | code = GT_EXPR; | |
2969 | break; | |
2970 | case LE_EXPR: | |
2971 | code = GE_EXPR; | |
2972 | break; | |
2973 | } | |
2974 | TREE_SET_CODE (t, code); | |
2975 | } | |
2976 | ||
2977 | /* Convert foo++ == CONST into ++foo == CONST + INCR. | |
2978 | First, see if one arg is constant; find the constant arg | |
2979 | and the other one. */ | |
2980 | { | |
2981 | tree constop = 0, varop; | |
2982 | tree *constoploc; | |
2983 | ||
2984 | if (TREE_CONSTANT (arg1)) | |
2985 | constoploc = &TREE_OPERAND (t, 1), constop = arg1, varop = arg0; | |
2986 | if (TREE_CONSTANT (arg0)) | |
2987 | constoploc = &TREE_OPERAND (t, 0), constop = arg0, varop = arg1; | |
2988 | ||
2989 | if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR) | |
2990 | { | |
2991 | tree newconst | |
2992 | = fold (build (PLUS_EXPR, TREE_TYPE (varop), | |
2993 | constop, TREE_OPERAND (varop, 1))); | |
2994 | /* This optimization is invalid for ordered comparisons | |
2995 | if CONST+INCR overflows or if foo+incr might overflow. | |
2996 | For pointer types we assume overflow doesn't happen. */ | |
2997 | if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE | |
2998 | || code == EQ_EXPR || code == NE_EXPR) | |
2999 | { | |
3000 | /* This optimization is invalid for floating point | |
3001 | if adding one to the constant does not change it. */ | |
3002 | if (TREE_CODE (TREE_TYPE (newconst)) != REAL_TYPE | |
3003 | || !REAL_VALUES_EQUAL (TREE_REAL_CST (newconst), | |
3004 | TREE_REAL_CST (constop))) | |
3005 | { | |
3006 | TREE_SET_CODE (varop, PREINCREMENT_EXPR); | |
3007 | *constoploc = newconst; | |
3008 | return t; | |
3009 | } | |
3010 | } | |
3011 | } | |
3012 | else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR) | |
3013 | { | |
3014 | tree newconst | |
3015 | = fold (build (MINUS_EXPR, TREE_TYPE (varop), | |
3016 | constop, TREE_OPERAND (varop, 1))); | |
3017 | if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE | |
3018 | || code == EQ_EXPR || code == NE_EXPR) | |
3019 | { | |
3020 | if (TREE_CODE (TREE_TYPE (newconst)) != REAL_TYPE | |
3021 | || !REAL_VALUES_EQUAL (TREE_REAL_CST (newconst), | |
3022 | TREE_REAL_CST (constop))) | |
3023 | { | |
3024 | TREE_SET_CODE (varop, PREDECREMENT_EXPR); | |
3025 | *constoploc = newconst; | |
3026 | return t; | |
3027 | } | |
3028 | } | |
3029 | } | |
3030 | } | |
3031 | ||
3032 | /* Change X >= CST to X > (CST - 1) if CST is positive. */ | |
3033 | if (TREE_CODE (arg1) == INTEGER_CST | |
3034 | && TREE_CODE (arg0) != INTEGER_CST | |
3035 | && ! tree_int_cst_lt (arg1, integer_one_node)) | |
3036 | { | |
3037 | switch (TREE_CODE (t)) | |
3038 | { | |
3039 | case GE_EXPR: | |
3040 | code = GT_EXPR; | |
3041 | TREE_SET_CODE (t, code); | |
3042 | arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node); | |
3043 | TREE_OPERAND (t, 1) = arg1; | |
3044 | break; | |
3045 | ||
3046 | case LT_EXPR: | |
3047 | code = LE_EXPR; | |
3048 | TREE_SET_CODE (t, code); | |
3049 | arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node); | |
3050 | TREE_OPERAND (t, 1) = arg1; | |
3051 | } | |
3052 | } | |
3053 | ||
3054 | /* If we are comparing the result of a comparison to a constant, | |
3055 | we can often simplify this, since the comparison result is known to | |
3056 | be either 0 or 1. We can ignore conversions if the LHS is a | |
3057 | comparison. */ | |
3058 | ||
3059 | if (TREE_CODE (arg1) == INTEGER_CST) | |
3060 | { | |
3061 | tree comparison = arg0; | |
3062 | ||
3063 | while (TREE_CODE (comparison) == NOP_EXPR | |
3064 | || TREE_CODE (comparison) == CONVERT_EXPR) | |
3065 | comparison = TREE_OPERAND (comparison, 0); | |
3066 | ||
3067 | if (TREE_CODE_CLASS (TREE_CODE (comparison)) == '<' | |
3068 | || TREE_CODE (comparison) == TRUTH_ANDIF_EXPR | |
3069 | || TREE_CODE (comparison) == TRUTH_ORIF_EXPR | |
3070 | || TREE_CODE (comparison) == TRUTH_AND_EXPR | |
3071 | || TREE_CODE (comparison) == TRUTH_OR_EXPR | |
3072 | || TREE_CODE (comparison) == TRUTH_NOT_EXPR) | |
3073 | { | |
3074 | /* We do different things depending on whether the | |
3075 | constant being compared against is < 0, == 0, == 1, or > 1. | |
3076 | Each of those cases, in order, corresponds to one | |
3077 | character in a string. The value of the character is | |
3078 | the result to return. A '0' or '1' means return always true | |
3079 | or always false, respectively; 'c' means return the result | |
3080 | of the comparison, and 'i' means return the result of the | |
3081 | inverted comparison. */ | |
3082 | ||
3083 | char *actions, action; | |
3084 | ||
3085 | switch (code) | |
3086 | { | |
3087 | case EQ_EXPR: | |
3088 | actions = "0ic0"; | |
3089 | break; | |
3090 | case NE_EXPR: | |
3091 | actions = "1ci1"; | |
3092 | break; | |
3093 | case LE_EXPR: | |
3094 | actions = "0i11"; | |
3095 | break; | |
3096 | case LT_EXPR: | |
3097 | actions = "00i1"; | |
3098 | break; | |
3099 | case GE_EXPR: | |
3100 | actions = "11c0"; | |
3101 | break; | |
3102 | case GT_EXPR: | |
3103 | actions = "1c00"; | |
3104 | break; | |
3105 | } | |
3106 | ||
3107 | if (tree_int_cst_lt (arg1, integer_zero_node)) | |
3108 | action = actions[0]; | |
3109 | else if (integer_zerop (arg1)) | |
3110 | action = actions[1]; | |
3111 | else if (integer_onep (arg1)) | |
3112 | action = actions[2]; | |
3113 | else | |
3114 | action = actions[3]; | |
3115 | ||
3116 | switch (action) | |
3117 | { | |
3118 | case '0': | |
3119 | return omit_one_operand (type, integer_zero_node, | |
3120 | comparison); | |
3121 | ||
3122 | case '1': | |
3123 | return omit_one_operand (type, integer_one_node, comparison); | |
3124 | ||
3125 | case 'c': | |
3126 | return convert (type, comparison); | |
3127 | ||
3128 | case 'i': | |
3129 | return convert (type, invert_truthvalue (comparison)); | |
3130 | ||
3131 | default: | |
3132 | abort (); | |
3133 | } | |
3134 | } | |
3135 | } | |
3136 | ||
3137 | /* If this is an EQ or NE comparison with zero and ARG0 is | |
3138 | (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require | |
3139 | two operations, but the latter can be done in one less insn | |
3140 | one machine that have only two-operand insns or on which a | |
3141 | constant cannot be the first operand. */ | |
3142 | if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR) | |
3143 | && TREE_CODE (arg0) == BIT_AND_EXPR) | |
3144 | { | |
3145 | if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR | |
3146 | && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0))) | |
3147 | return | |
3148 | fold (build (code, type, | |
3149 | build (BIT_AND_EXPR, TREE_TYPE (arg0), | |
3150 | build (RSHIFT_EXPR, | |
3151 | TREE_TYPE (TREE_OPERAND (arg0, 0)), | |
3152 | TREE_OPERAND (arg0, 1), | |
3153 | TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)), | |
3154 | convert (TREE_TYPE (arg0), | |
3155 | integer_one_node)), | |
3156 | arg1)); | |
3157 | else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR | |
3158 | && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0))) | |
3159 | return | |
3160 | fold (build (code, type, | |
3161 | build (BIT_AND_EXPR, TREE_TYPE (arg0), | |
3162 | build (RSHIFT_EXPR, | |
3163 | TREE_TYPE (TREE_OPERAND (arg0, 1)), | |
3164 | TREE_OPERAND (arg0, 0), | |
3165 | TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)), | |
3166 | convert (TREE_TYPE (arg0), | |
3167 | integer_one_node)), | |
3168 | arg1)); | |
3169 | } | |
3170 | ||
3171 | /* If this is an NE comparison of zero with an AND of one, remove the | |
3172 | comparison since the AND will give the correct value. */ | |
3173 | if (code == NE_EXPR && integer_zerop (arg1) | |
3174 | && TREE_CODE (arg0) == BIT_AND_EXPR | |
3175 | && integer_onep (TREE_OPERAND (arg0, 1))) | |
3176 | return convert (type, arg0); | |
3177 | ||
3178 | /* If we have (A & C) == C where C is a power of 2, convert this into | |
3179 | (A & C) != 0. Similarly for NE_EXPR. */ | |
3180 | if ((code == EQ_EXPR || code == NE_EXPR) | |
3181 | && TREE_CODE (arg0) == BIT_AND_EXPR | |
3182 | && integer_pow2p (TREE_OPERAND (arg0, 1)) | |
3183 | && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) | |
3184 | return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, | |
3185 | arg0, integer_zero_node); | |
3186 | ||
3187 | /* Simplify comparison of an integer with itself. | |
3188 | (This may not be safe with IEEE floats if they are nans.) */ | |
3189 | if (operand_equal_p (arg0, arg1, 0) | |
3190 | && TREE_CODE (TREE_TYPE (arg1)) == INTEGER_TYPE) | |
3191 | { | |
3192 | switch (code) | |
3193 | { | |
3194 | case EQ_EXPR: | |
3195 | case GE_EXPR: | |
3196 | case LE_EXPR: | |
3197 | t = build_int_2 (1, 0); | |
3198 | TREE_TYPE (t) = type; | |
3199 | return t; | |
3200 | case NE_EXPR: | |
3201 | case GT_EXPR: | |
3202 | case LT_EXPR: | |
3203 | t = build_int_2 (0, 0); | |
3204 | TREE_TYPE (t) = type; | |
3205 | return t; | |
3206 | } | |
3207 | } | |
3208 | ||
3209 | /* An unsigned comparison against 0 can be simplified. */ | |
3210 | if (integer_zerop (arg1) | |
3211 | && (TREE_CODE (TREE_TYPE (arg1)) == INTEGER_TYPE | |
3212 | || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE) | |
3213 | && TREE_UNSIGNED (TREE_TYPE (arg1))) | |
3214 | { | |
3215 | switch (TREE_CODE (t)) | |
3216 | { | |
3217 | case GT_EXPR: | |
3218 | TREE_SET_CODE (t, NE_EXPR); | |
3219 | break; | |
3220 | case LE_EXPR: | |
3221 | TREE_SET_CODE (t, EQ_EXPR); | |
3222 | break; | |
3223 | case GE_EXPR: | |
3224 | return omit_one_operand (integer_type_node, | |
3225 | integer_one_node, arg0); | |
3226 | case LT_EXPR: | |
3227 | return omit_one_operand (integer_type_node, | |
3228 | integer_zero_node, arg0); | |
3229 | } | |
3230 | } | |
3231 | ||
3232 | /* To compute GT, swap the arguments and do LT. | |
3233 | To compute GE, do LT and invert the result. | |
3234 | To compute LE, swap the arguments, do LT and invert the result. | |
3235 | To compute NE, do EQ and invert the result. */ | |
3236 | if (code == LE_EXPR || code == GT_EXPR) | |
3237 | { | |
3238 | register tree temp = arg0; | |
3239 | arg0 = arg1; | |
3240 | arg1 = temp; | |
3241 | } | |
3242 | ||
3243 | /* Compute a result for LT or EQ if args permit; | |
3244 | otherwise return T. */ | |
3245 | if (TREE_CODE (arg0) == INTEGER_CST | |
3246 | && TREE_CODE (arg1) == INTEGER_CST) | |
3247 | { | |
3248 | if (code == EQ_EXPR || code == NE_EXPR) | |
3249 | t = build_int_2 | |
3250 | (TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1) | |
3251 | && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1), | |
3252 | 0); | |
3253 | else | |
3254 | t = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0)) | |
3255 | ? INT_CST_LT_UNSIGNED (arg0, arg1) | |
3256 | : INT_CST_LT (arg0, arg1)), | |
3257 | 0); | |
3258 | } | |
3259 | /* Assume a nonexplicit constant cannot equal an explicit one, | |
3260 | since such code would be undefined anyway. | |
3261 | Exception: on sysvr4, using #pragma weak, | |
3262 | a label can come out as 0. */ | |
3263 | else if (TREE_CODE (arg1) == INTEGER_CST | |
3264 | && !integer_zerop (arg1) | |
3265 | && TREE_CONSTANT (arg0) | |
3266 | && TREE_CODE (arg0) == ADDR_EXPR | |
3267 | && (code == EQ_EXPR || code == NE_EXPR)) | |
3268 | { | |
3269 | t = build_int_2 (0, 0); | |
3270 | } | |
3271 | /* Two real constants can be compared explicitly. */ | |
3272 | else if (TREE_CODE (arg0) == REAL_CST | |
3273 | && TREE_CODE (arg1) == REAL_CST) | |
3274 | { | |
3275 | if (code == EQ_EXPR || code == NE_EXPR) | |
3276 | t = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), | |
3277 | TREE_REAL_CST (arg1)), | |
3278 | 0); | |
3279 | else | |
3280 | t = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0), | |
3281 | TREE_REAL_CST (arg1)), | |
3282 | 0); | |
3283 | } | |
3284 | else if ((TREE_CODE (arg0) == COMPONENT_REF | |
3285 | || TREE_CODE (arg0) == BIT_FIELD_REF) | |
3286 | && (code == EQ_EXPR || code == NE_EXPR) | |
3287 | /* Handle the constant case even without -O | |
3288 | to make sure the warnings are given. */ | |
3289 | && (optimize || TREE_CODE (arg1) == INTEGER_CST)) | |
3290 | { | |
3291 | tree tem = optimize_bit_field_compare (code, type, arg0, arg1); | |
3292 | return tem ? tem : t; | |
3293 | } | |
3294 | ||
3295 | /* If what we want is other than LT or EQ, invert the result. */ | |
3296 | if (code == GE_EXPR || code == LE_EXPR || code == NE_EXPR) | |
3297 | TREE_INT_CST_LOW (t) ^= 1; | |
3298 | TREE_TYPE (t) = type; | |
3299 | return t; | |
3300 | ||
3301 | case COND_EXPR: | |
3302 | if (TREE_CODE (arg0) == INTEGER_CST) | |
3303 | return TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)); | |
3304 | else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0)) | |
3305 | return omit_one_operand (type, arg1, arg0); | |
3306 | else if (integer_onep (TREE_OPERAND (t, 1)) | |
3307 | && integer_zerop (TREE_OPERAND (t, 2)) | |
3308 | /* If we try to convert TREE_OPERAND (t, 0) to our type, the | |
3309 | call to fold will try to move the conversion inside | |
3310 | a COND, which will recurse. In that case, the COND_EXPR | |
3311 | is probably the best choice, so leave it alone. */ | |
3312 | && type == TREE_TYPE (arg0)) | |
3313 | return arg0; | |
3314 | else if (integer_zerop (arg1) && integer_onep (TREE_OPERAND (t, 2))) | |
3315 | return convert (type, invert_truthvalue (arg0)); | |
3316 | ||
3317 | /* If we have (a >= 0 ? a : -a) or the same with ">", this is an | |
3318 | absolute value expression. */ | |
3319 | ||
3320 | if ((TREE_CODE (arg0) == GE_EXPR || TREE_CODE (arg0) == GT_EXPR) | |
3321 | && integer_zerop (TREE_OPERAND (arg0, 1)) | |
3322 | && TREE_CODE (TREE_OPERAND (t, 2)) == NEGATE_EXPR | |
3323 | && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) | |
3324 | && operand_equal_p (TREE_OPERAND (TREE_OPERAND (t, 2), 0), arg1, 0)) | |
3325 | return fold (build1 (ABS_EXPR, type, arg1)); | |
3326 | ||
3327 | /* Similarly for (a <= 0 ? -a : a). */ | |
3328 | ||
3329 | if ((TREE_CODE (arg0) == LE_EXPR || TREE_CODE (arg0) == LT_EXPR) | |
3330 | && integer_zerop (TREE_OPERAND (arg0, 1)) | |
3331 | && TREE_CODE (arg1) == NEGATE_EXPR | |
3332 | && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (t, 2), 0) | |
3333 | && operand_equal_p (TREE_OPERAND (arg1, 0), TREE_OPERAND (t, 2), 0)) | |
3334 | return fold (build1 (ABS_EXPR, type, TREE_OPERAND (t, 2))); | |
3335 | ||
3336 | /* If we have a GT, GE, LT, or LE comparison, this might be a MIN or | |
3337 | MAX test. If so, make a MIN_EXPR or MAX_EXPR. */ | |
3338 | ||
3339 | if (TREE_CODE (arg0) == GT_EXPR || TREE_CODE (arg0) == GE_EXPR | |
3340 | || TREE_CODE (arg0) == LT_EXPR || TREE_CODE (arg0) == LE_EXPR) | |
3341 | { | |
3342 | tree hi_true, lo_true; | |
3343 | ||
3344 | if (TREE_CODE (arg0) == GT_EXPR || TREE_CODE (arg0) == GE_EXPR) | |
3345 | hi_true = TREE_OPERAND (arg0, 0), lo_true = TREE_OPERAND (arg0, 1); | |
3346 | else | |
3347 | hi_true = TREE_OPERAND (arg0, 1), lo_true = TREE_OPERAND (arg0, 0); | |
3348 | ||
3349 | if (comparison_equiv_p (hi_true, lo_true, arg1, TREE_OPERAND (t, 2))) | |
3350 | /* We use arg1 and the other arg because they must have the same | |
3351 | type as the intended result. | |
3352 | The values being compared might have a narrower type. */ | |
3353 | return fold (build (MAX_EXPR, type, arg1, TREE_OPERAND (t, 2))); | |
3354 | else if (comparison_equiv_p (lo_true, hi_true, | |
3355 | arg1, TREE_OPERAND (t, 2))) | |
3356 | return fold (build (MIN_EXPR, type, arg1, TREE_OPERAND (t, 2))); | |
3357 | } | |
3358 | ||
3359 | /* Look for cases when we are comparing some expression A for equality | |
3360 | with zero and the result is to be zero if A is zero. In that case, | |
3361 | check to see if the value of A is the same as the value to be | |
3362 | returned when A is non-zero. | |
3363 | ||
3364 | There are two cases: One is where we have (A ? A : 0) and the | |
3365 | other is when a single bit is tested (e.g., A & 2 ? 2 : 0). | |
3366 | In these cases, the result of the conditional is simply A. | |
3367 | ||
3368 | Start by setting ARG1 to be the true value and ARG0 to be the thing | |
3369 | compared with zero. Then check for the two cases above. */ | |
3370 | ||
3371 | if (integer_zerop (TREE_OPERAND (t, 2)) | |
3372 | && TREE_CODE (arg0) == NE_EXPR | |
3373 | && integer_zerop (TREE_OPERAND (arg0, 1)) | |
3374 | && ! TREE_SIDE_EFFECTS (arg1)) | |
3375 | ; | |
3376 | else if (integer_zerop (arg1) | |
3377 | && TREE_CODE (arg0) == EQ_EXPR | |
3378 | && integer_zerop (TREE_OPERAND (arg0, 1)) | |
3379 | && ! TREE_SIDE_EFFECTS (TREE_OPERAND (t, 2))) | |
3380 | arg1 = TREE_OPERAND (t, 2); | |
3381 | else | |
3382 | return t; | |
3383 | ||
3384 | arg0 = TREE_OPERAND (arg0, 0); | |
3385 | ||
3386 | STRIP_NOPS (arg1); | |
3387 | if (operand_equal_p (arg0, arg1, 0) | |
3388 | || (TREE_CODE (arg1) == INTEGER_CST | |
3389 | && integer_pow2p (arg1) | |
3390 | && TREE_CODE (arg0) == BIT_AND_EXPR | |
3391 | && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))) | |
3392 | return convert (type, arg0); | |
3393 | return t; | |
3394 | ||
3395 | case COMPOUND_EXPR: | |
3396 | if (!TREE_SIDE_EFFECTS (arg0)) | |
3397 | return arg1; | |
3398 | return t; | |
3399 | ||
3400 | default: | |
3401 | return t; | |
3402 | } /* switch (code) */ | |
3403 | } |