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ac534736 | 1 | /* Tail call optimization on trees. |
23a5b65a | 2 | Copyright (C) 2003-2014 Free Software Foundation, Inc. |
6de9cd9a DN |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
9dcd6f09 | 8 | the Free Software Foundation; either version 3, or (at your option) |
6de9cd9a DN |
9 | any later version. |
10 | ||
11 | GCC 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 | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
23 | #include "tm.h" | |
24 | #include "tree.h" | |
d8a2d370 | 25 | #include "stor-layout.h" |
6de9cd9a | 26 | #include "tm_p.h" |
60393bbc AM |
27 | #include "predict.h" |
28 | #include "vec.h" | |
83685514 AM |
29 | #include "hashtab.h" |
30 | #include "hash-set.h" | |
83685514 AM |
31 | #include "machmode.h" |
32 | #include "hard-reg-set.h" | |
33 | #include "input.h" | |
6de9cd9a | 34 | #include "function.h" |
60393bbc AM |
35 | #include "dominance.h" |
36 | #include "cfg.h" | |
37 | #include "basic-block.h" | |
2fb9a547 AM |
38 | #include "tree-ssa-alias.h" |
39 | #include "internal-fn.h" | |
40 | #include "gimple-expr.h" | |
41 | #include "is-a.h" | |
18f429e2 | 42 | #include "gimple.h" |
5be5c238 | 43 | #include "gimple-iterator.h" |
18f429e2 | 44 | #include "gimplify-me.h" |
442b4905 AM |
45 | #include "gimple-ssa.h" |
46 | #include "tree-cfg.h" | |
47 | #include "tree-phinodes.h" | |
d8a2d370 | 48 | #include "stringpool.h" |
442b4905 AM |
49 | #include "tree-ssanames.h" |
50 | #include "tree-into-ssa.h" | |
d8a2d370 | 51 | #include "expr.h" |
442b4905 | 52 | #include "tree-dfa.h" |
cf835838 | 53 | #include "gimple-pretty-print.h" |
6de9cd9a DN |
54 | #include "except.h" |
55 | #include "tree-pass.h" | |
56 | #include "flags.h" | |
57 | #include "langhooks.h" | |
6fb5fa3c | 58 | #include "dbgcnt.h" |
f0a0390e | 59 | #include "target.h" |
0d5049b2 | 60 | #include "cfgloop.h" |
677f3fa8 | 61 | #include "common/common-target.h" |
c582198b AM |
62 | #include "hash-map.h" |
63 | #include "plugin-api.h" | |
64 | #include "ipa-ref.h" | |
65 | #include "cgraph.h" | |
fc11f321 | 66 | #include "ipa-utils.h" |
6de9cd9a DN |
67 | |
68 | /* The file implements the tail recursion elimination. It is also used to | |
1ea7e6ad | 69 | analyze the tail calls in general, passing the results to the rtl level |
6de9cd9a DN |
70 | where they are used for sibcall optimization. |
71 | ||
72 | In addition to the standard tail recursion elimination, we handle the most | |
73 | trivial cases of making the call tail recursive by creating accumulators. | |
74 | For example the following function | |
75 | ||
76 | int sum (int n) | |
77 | { | |
78 | if (n > 0) | |
79 | return n + sum (n - 1); | |
80 | else | |
81 | return 0; | |
82 | } | |
83 | ||
84 | is transformed into | |
85 | ||
86 | int sum (int n) | |
87 | { | |
88 | int acc = 0; | |
89 | ||
90 | while (n > 0) | |
91 | acc += n--; | |
92 | ||
93 | return acc; | |
94 | } | |
95 | ||
b8698a0f | 96 | To do this, we maintain two accumulators (a_acc and m_acc) that indicate |
6de9cd9a DN |
97 | when we reach the return x statement, we should return a_acc + x * m_acc |
98 | instead. They are initially initialized to 0 and 1, respectively, | |
99 | so the semantics of the function is obviously preserved. If we are | |
100 | guaranteed that the value of the accumulator never change, we | |
101 | omit the accumulator. | |
102 | ||
103 | There are three cases how the function may exit. The first one is | |
6ce2bcb7 | 104 | handled in adjust_return_value, the other two in adjust_accumulator_values |
6de9cd9a DN |
105 | (the second case is actually a special case of the third one and we |
106 | present it separately just for clarity): | |
107 | ||
108 | 1) Just return x, where x is not in any of the remaining special shapes. | |
109 | We rewrite this to a gimple equivalent of return m_acc * x + a_acc. | |
b8698a0f | 110 | |
6de9cd9a | 111 | 2) return f (...), where f is the current function, is rewritten in a |
1ea7e6ad | 112 | classical tail-recursion elimination way, into assignment of arguments |
6de9cd9a DN |
113 | and jump to the start of the function. Values of the accumulators |
114 | are unchanged. | |
b8698a0f | 115 | |
6de9cd9a DN |
116 | 3) return a + m * f(...), where a and m do not depend on call to f. |
117 | To preserve the semantics described before we want this to be rewritten | |
118 | in such a way that we finally return | |
119 | ||
120 | a_acc + (a + m * f(...)) * m_acc = (a_acc + a * m_acc) + (m * m_acc) * f(...). | |
121 | ||
122 | I.e. we increase a_acc by a * m_acc, multiply m_acc by m and | |
123 | eliminate the tail call to f. Special cases when the value is just | |
124 | added or just multiplied are obtained by setting a = 0 or m = 1. | |
125 | ||
126 | TODO -- it is possible to do similar tricks for other operations. */ | |
127 | ||
128 | /* A structure that describes the tailcall. */ | |
129 | ||
130 | struct tailcall | |
131 | { | |
6de9cd9a | 132 | /* The iterator pointing to the call statement. */ |
726a989a | 133 | gimple_stmt_iterator call_gsi; |
6de9cd9a DN |
134 | |
135 | /* True if it is a call to the current function. */ | |
136 | bool tail_recursion; | |
137 | ||
138 | /* The return value of the caller is mult * f + add, where f is the return | |
139 | value of the call. */ | |
140 | tree mult, add; | |
141 | ||
142 | /* Next tailcall in the chain. */ | |
143 | struct tailcall *next; | |
144 | }; | |
145 | ||
146 | /* The variables holding the value of multiplicative and additive | |
147 | accumulator. */ | |
148 | static tree m_acc, a_acc; | |
149 | ||
150 | static bool suitable_for_tail_opt_p (void); | |
151 | static bool optimize_tail_call (struct tailcall *, bool); | |
152 | static void eliminate_tail_call (struct tailcall *); | |
153 | static void find_tail_calls (basic_block, struct tailcall **); | |
154 | ||
155 | /* Returns false when the function is not suitable for tail call optimization | |
156 | from some reason (e.g. if it takes variable number of arguments). */ | |
157 | ||
158 | static bool | |
159 | suitable_for_tail_opt_p (void) | |
160 | { | |
e3b5732b | 161 | if (cfun->stdarg) |
6de9cd9a DN |
162 | return false; |
163 | ||
6de9cd9a DN |
164 | return true; |
165 | } | |
166 | /* Returns false when the function is not suitable for tail call optimization | |
167 | from some reason (e.g. if it takes variable number of arguments). | |
168 | This test must pass in addition to suitable_for_tail_opt_p in order to make | |
169 | tail call discovery happen. */ | |
170 | ||
171 | static bool | |
172 | suitable_for_tail_call_opt_p (void) | |
173 | { | |
ead553a1 SB |
174 | tree param; |
175 | ||
6de9cd9a DN |
176 | /* alloca (until we have stack slot life analysis) inhibits |
177 | sibling call optimizations, but not tail recursion. */ | |
e3b5732b | 178 | if (cfun->calls_alloca) |
6de9cd9a DN |
179 | return false; |
180 | ||
181 | /* If we are using sjlj exceptions, we may need to add a call to | |
182 | _Unwind_SjLj_Unregister at exit of the function. Which means | |
183 | that we cannot do any sibcall transformations. */ | |
677f3fa8 | 184 | if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ |
f0a0390e | 185 | && current_function_has_exception_handlers ()) |
6de9cd9a DN |
186 | return false; |
187 | ||
188 | /* Any function that calls setjmp might have longjmp called from | |
189 | any called function. ??? We really should represent this | |
190 | properly in the CFG so that this needn't be special cased. */ | |
e3b5732b | 191 | if (cfun->calls_setjmp) |
6de9cd9a DN |
192 | return false; |
193 | ||
ead553a1 SB |
194 | /* ??? It is OK if the argument of a function is taken in some cases, |
195 | but not in all cases. See PR15387 and PR19616. Revisit for 4.1. */ | |
196 | for (param = DECL_ARGUMENTS (current_function_decl); | |
197 | param; | |
910ad8de | 198 | param = DECL_CHAIN (param)) |
ead553a1 SB |
199 | if (TREE_ADDRESSABLE (param)) |
200 | return false; | |
201 | ||
6de9cd9a DN |
202 | return true; |
203 | } | |
204 | ||
205 | /* Checks whether the expression EXPR in stmt AT is independent of the | |
726a989a RB |
206 | statement pointed to by GSI (in a sense that we already know EXPR's value |
207 | at GSI). We use the fact that we are only called from the chain of | |
6de9cd9a | 208 | basic blocks that have only single successor. Returns the expression |
726a989a | 209 | containing the value of EXPR at GSI. */ |
6de9cd9a DN |
210 | |
211 | static tree | |
726a989a | 212 | independent_of_stmt_p (tree expr, gimple at, gimple_stmt_iterator gsi) |
6de9cd9a DN |
213 | { |
214 | basic_block bb, call_bb, at_bb; | |
215 | edge e; | |
628f6a4e | 216 | edge_iterator ei; |
6de9cd9a DN |
217 | |
218 | if (is_gimple_min_invariant (expr)) | |
219 | return expr; | |
220 | ||
221 | if (TREE_CODE (expr) != SSA_NAME) | |
222 | return NULL_TREE; | |
223 | ||
224 | /* Mark the blocks in the chain leading to the end. */ | |
726a989a RB |
225 | at_bb = gimple_bb (at); |
226 | call_bb = gimple_bb (gsi_stmt (gsi)); | |
c5cbcccf | 227 | for (bb = call_bb; bb != at_bb; bb = single_succ (bb)) |
6de9cd9a DN |
228 | bb->aux = &bb->aux; |
229 | bb->aux = &bb->aux; | |
230 | ||
231 | while (1) | |
b8698a0f | 232 | { |
6de9cd9a | 233 | at = SSA_NAME_DEF_STMT (expr); |
726a989a | 234 | bb = gimple_bb (at); |
6de9cd9a | 235 | |
61ada8ae | 236 | /* The default definition or defined before the chain. */ |
6de9cd9a DN |
237 | if (!bb || !bb->aux) |
238 | break; | |
239 | ||
240 | if (bb == call_bb) | |
241 | { | |
726a989a RB |
242 | for (; !gsi_end_p (gsi); gsi_next (&gsi)) |
243 | if (gsi_stmt (gsi) == at) | |
6de9cd9a DN |
244 | break; |
245 | ||
726a989a | 246 | if (!gsi_end_p (gsi)) |
6de9cd9a DN |
247 | expr = NULL_TREE; |
248 | break; | |
249 | } | |
250 | ||
726a989a | 251 | if (gimple_code (at) != GIMPLE_PHI) |
6de9cd9a DN |
252 | { |
253 | expr = NULL_TREE; | |
254 | break; | |
255 | } | |
256 | ||
628f6a4e | 257 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
258 | if (e->src->aux) |
259 | break; | |
1e128c5f | 260 | gcc_assert (e); |
6de9cd9a | 261 | |
d00ad49b | 262 | expr = PHI_ARG_DEF_FROM_EDGE (at, e); |
066a0344 ZD |
263 | if (TREE_CODE (expr) != SSA_NAME) |
264 | { | |
265 | /* The value is a constant. */ | |
266 | break; | |
267 | } | |
6de9cd9a DN |
268 | } |
269 | ||
270 | /* Unmark the blocks. */ | |
c5cbcccf | 271 | for (bb = call_bb; bb != at_bb; bb = single_succ (bb)) |
6de9cd9a DN |
272 | bb->aux = NULL; |
273 | bb->aux = NULL; | |
274 | ||
275 | return expr; | |
276 | } | |
277 | ||
726a989a RB |
278 | /* Simulates the effect of an assignment STMT on the return value of the tail |
279 | recursive CALL passed in ASS_VAR. M and A are the multiplicative and the | |
280 | additive factor for the real return value. */ | |
6de9cd9a DN |
281 | |
282 | static bool | |
726a989a | 283 | process_assignment (gimple stmt, gimple_stmt_iterator call, tree *m, |
6de9cd9a DN |
284 | tree *a, tree *ass_var) |
285 | { | |
68fce4ed | 286 | tree op0, op1 = NULL_TREE, non_ass_var = NULL_TREE; |
726a989a RB |
287 | tree dest = gimple_assign_lhs (stmt); |
288 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
289 | enum gimple_rhs_class rhs_class = get_gimple_rhs_class (code); | |
290 | tree src_var = gimple_assign_rhs1 (stmt); | |
b8698a0f | 291 | |
b89e96ac SB |
292 | /* See if this is a simple copy operation of an SSA name to the function |
293 | result. In that case we may have a simple tail call. Ignore type | |
294 | conversions that can never produce extra code between the function | |
295 | call and the function return. */ | |
726a989a RB |
296 | if ((rhs_class == GIMPLE_SINGLE_RHS || gimple_assign_cast_p (stmt)) |
297 | && (TREE_CODE (src_var) == SSA_NAME)) | |
6de9cd9a | 298 | { |
726a989a RB |
299 | /* Reject a tailcall if the type conversion might need |
300 | additional code. */ | |
62fb101e JJ |
301 | if (gimple_assign_cast_p (stmt)) |
302 | { | |
303 | if (TYPE_MODE (TREE_TYPE (dest)) != TYPE_MODE (TREE_TYPE (src_var))) | |
304 | return false; | |
305 | ||
306 | /* Even if the type modes are the same, if the precision of the | |
307 | type is smaller than mode's precision, | |
308 | reduce_to_bit_field_precision would generate additional code. */ | |
309 | if (INTEGRAL_TYPE_P (TREE_TYPE (dest)) | |
310 | && (GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (dest))) | |
311 | > TYPE_PRECISION (TREE_TYPE (dest)))) | |
312 | return false; | |
313 | } | |
726a989a | 314 | |
b89e96ac | 315 | if (src_var != *ass_var) |
6de9cd9a DN |
316 | return false; |
317 | ||
318 | *ass_var = dest; | |
319 | return true; | |
320 | } | |
321 | ||
68fce4ed GS |
322 | switch (rhs_class) |
323 | { | |
324 | case GIMPLE_BINARY_RHS: | |
325 | op1 = gimple_assign_rhs2 (stmt); | |
326 | ||
327 | /* Fall through. */ | |
328 | ||
329 | case GIMPLE_UNARY_RHS: | |
330 | op0 = gimple_assign_rhs1 (stmt); | |
331 | break; | |
332 | ||
333 | default: | |
334 | return false; | |
335 | } | |
6de9cd9a | 336 | |
85d62520 RS |
337 | /* Accumulator optimizations will reverse the order of operations. |
338 | We can only do that for floating-point types if we're assuming | |
339 | that addition and multiplication are associative. */ | |
a1a82611 | 340 | if (!flag_associative_math) |
85d62520 RS |
341 | if (FLOAT_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))) |
342 | return false; | |
343 | ||
68fce4ed GS |
344 | if (rhs_class == GIMPLE_UNARY_RHS) |
345 | ; | |
346 | else if (op0 == *ass_var | |
6b00d7dd | 347 | && (non_ass_var = independent_of_stmt_p (op1, stmt, call))) |
6de9cd9a DN |
348 | ; |
349 | else if (op1 == *ass_var | |
350 | && (non_ass_var = independent_of_stmt_p (op0, stmt, call))) | |
351 | ; | |
352 | else | |
353 | return false; | |
354 | ||
b89e96ac | 355 | switch (code) |
6de9cd9a DN |
356 | { |
357 | case PLUS_EXPR: | |
6de9cd9a DN |
358 | *a = non_ass_var; |
359 | *ass_var = dest; | |
360 | return true; | |
361 | ||
6b00d7dd JJ |
362 | case POINTER_PLUS_EXPR: |
363 | if (op0 != *ass_var) | |
364 | return false; | |
365 | *a = non_ass_var; | |
366 | *ass_var = dest; | |
367 | return true; | |
368 | ||
6de9cd9a | 369 | case MULT_EXPR: |
6de9cd9a DN |
370 | *m = non_ass_var; |
371 | *ass_var = dest; | |
372 | return true; | |
373 | ||
68fce4ed | 374 | case NEGATE_EXPR: |
4e115102 | 375 | *m = build_minus_one_cst (TREE_TYPE (op0)); |
68fce4ed GS |
376 | *ass_var = dest; |
377 | return true; | |
378 | ||
379 | case MINUS_EXPR: | |
380 | if (*ass_var == op0) | |
381 | *a = fold_build1 (NEGATE_EXPR, TREE_TYPE (non_ass_var), non_ass_var); | |
382 | else | |
383 | { | |
4e115102 | 384 | *m = build_minus_one_cst (TREE_TYPE (non_ass_var)); |
68fce4ed GS |
385 | *a = fold_build1 (NEGATE_EXPR, TREE_TYPE (non_ass_var), non_ass_var); |
386 | } | |
387 | ||
388 | *ass_var = dest; | |
389 | return true; | |
390 | ||
391 | /* TODO -- Handle POINTER_PLUS_EXPR. */ | |
6de9cd9a DN |
392 | |
393 | default: | |
394 | return false; | |
395 | } | |
396 | } | |
397 | ||
398 | /* Propagate VAR through phis on edge E. */ | |
399 | ||
400 | static tree | |
401 | propagate_through_phis (tree var, edge e) | |
402 | { | |
403 | basic_block dest = e->dest; | |
726a989a | 404 | gimple_stmt_iterator gsi; |
b8698a0f | 405 | |
726a989a RB |
406 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
407 | { | |
408 | gimple phi = gsi_stmt (gsi); | |
409 | if (PHI_ARG_DEF_FROM_EDGE (phi, e) == var) | |
410 | return PHI_RESULT (phi); | |
411 | } | |
6de9cd9a DN |
412 | return var; |
413 | } | |
414 | ||
415 | /* Finds tailcalls falling into basic block BB. The list of found tailcalls is | |
416 | added to the start of RET. */ | |
417 | ||
418 | static void | |
419 | find_tail_calls (basic_block bb, struct tailcall **ret) | |
420 | { | |
726a989a RB |
421 | tree ass_var = NULL_TREE, ret_var, func, param; |
422 | gimple stmt, call = NULL; | |
423 | gimple_stmt_iterator gsi, agsi; | |
6de9cd9a DN |
424 | bool tail_recursion; |
425 | struct tailcall *nw; | |
426 | edge e; | |
427 | tree m, a; | |
428 | basic_block abb; | |
726a989a | 429 | size_t idx; |
12de6355 | 430 | tree var; |
6de9cd9a | 431 | |
c5cbcccf | 432 | if (!single_succ_p (bb)) |
6de9cd9a DN |
433 | return; |
434 | ||
726a989a | 435 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
6de9cd9a | 436 | { |
726a989a | 437 | stmt = gsi_stmt (gsi); |
6de9cd9a | 438 | |
ca786352 | 439 | /* Ignore labels, returns, clobbers and debug stmts. */ |
e106efc7 RG |
440 | if (gimple_code (stmt) == GIMPLE_LABEL |
441 | || gimple_code (stmt) == GIMPLE_RETURN | |
ca786352 | 442 | || gimple_clobber_p (stmt) |
e106efc7 | 443 | || is_gimple_debug (stmt)) |
6de9cd9a DN |
444 | continue; |
445 | ||
6de9cd9a | 446 | /* Check for a call. */ |
726a989a | 447 | if (is_gimple_call (stmt)) |
6de9cd9a | 448 | { |
6de9cd9a | 449 | call = stmt; |
726a989a RB |
450 | ass_var = gimple_call_lhs (stmt); |
451 | break; | |
6de9cd9a DN |
452 | } |
453 | ||
5006671f RG |
454 | /* If the statement references memory or volatile operands, fail. */ |
455 | if (gimple_references_memory_p (stmt) | |
456 | || gimple_has_volatile_ops (stmt)) | |
6de9cd9a DN |
457 | return; |
458 | } | |
459 | ||
726a989a | 460 | if (gsi_end_p (gsi)) |
6de9cd9a | 461 | { |
628f6a4e | 462 | edge_iterator ei; |
6de9cd9a | 463 | /* Recurse to the predecessors. */ |
628f6a4e | 464 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
465 | find_tail_calls (e->src, ret); |
466 | ||
467 | return; | |
468 | } | |
469 | ||
b8698a0f | 470 | /* If the LHS of our call is not just a simple register, we can't |
bd42a56b MM |
471 | transform this into a tail or sibling call. This situation happens, |
472 | in (e.g.) "*p = foo()" where foo returns a struct. In this case | |
473 | we won't have a temporary here, but we need to carry out the side | |
474 | effect anyway, so tailcall is impossible. | |
475 | ||
476 | ??? In some situations (when the struct is returned in memory via | |
477 | invisible argument) we could deal with this, e.g. by passing 'p' | |
478 | itself as that argument to foo, but it's too early to do this here, | |
479 | and expand_call() will not handle it anyway. If it ever can, then | |
480 | we need to revisit this here, to allow that situation. */ | |
481 | if (ass_var && !is_gimple_reg (ass_var)) | |
482 | return; | |
483 | ||
6de9cd9a DN |
484 | /* We found the call, check whether it is suitable. */ |
485 | tail_recursion = false; | |
726a989a | 486 | func = gimple_call_fndecl (call); |
16022041 RS |
487 | if (func |
488 | && !DECL_BUILT_IN (func) | |
489 | && recursive_call_p (current_function_decl, func)) | |
6de9cd9a | 490 | { |
12de6355 | 491 | tree arg; |
d086d311 | 492 | |
726a989a RB |
493 | for (param = DECL_ARGUMENTS (func), idx = 0; |
494 | param && idx < gimple_call_num_args (call); | |
910ad8de | 495 | param = DECL_CHAIN (param), idx ++) |
6de9cd9a | 496 | { |
726a989a | 497 | arg = gimple_call_arg (call, idx); |
14de86fa ZD |
498 | if (param != arg) |
499 | { | |
500 | /* Make sure there are no problems with copying. The parameter | |
6de9cd9a DN |
501 | have a copyable type and the two arguments must have reasonably |
502 | equivalent types. The latter requirement could be relaxed if | |
503 | we emitted a suitable type conversion statement. */ | |
14de86fa | 504 | if (!is_gimple_reg_type (TREE_TYPE (param)) |
f4088621 | 505 | || !useless_type_conversion_p (TREE_TYPE (param), |
726a989a | 506 | TREE_TYPE (arg))) |
14de86fa ZD |
507 | break; |
508 | ||
509 | /* The parameter should be a real operand, so that phi node | |
510 | created for it at the start of the function has the meaning | |
511 | of copying the value. This test implies is_gimple_reg_type | |
512 | from the previous condition, however this one could be | |
513 | relaxed by being more careful with copying the new value | |
726a989a | 514 | of the parameter (emitting appropriate GIMPLE_ASSIGN and |
14de86fa ZD |
515 | updating the virtual operands). */ |
516 | if (!is_gimple_reg (param)) | |
517 | break; | |
518 | } | |
6de9cd9a | 519 | } |
726a989a | 520 | if (idx == gimple_call_num_args (call) && !param) |
6de9cd9a | 521 | tail_recursion = true; |
12de6355 | 522 | } |
d086d311 | 523 | |
12de6355 RG |
524 | /* Make sure the tail invocation of this function does not refer |
525 | to local variables. */ | |
824f71b9 | 526 | FOR_EACH_LOCAL_DECL (cfun, idx, var) |
12de6355 | 527 | { |
4e708ff7 RG |
528 | if (TREE_CODE (var) != PARM_DECL |
529 | && auto_var_in_fn_p (var, cfun->decl) | |
52c307ba RG |
530 | && (ref_maybe_used_by_stmt_p (call, var) |
531 | || call_may_clobber_ref_p (call, var))) | |
12de6355 | 532 | return; |
6de9cd9a DN |
533 | } |
534 | ||
535 | /* Now check the statements after the call. None of them has virtual | |
536 | operands, so they may only depend on the call through its return | |
537 | value. The return value should also be dependent on each of them, | |
538 | since we are running after dce. */ | |
539 | m = NULL_TREE; | |
540 | a = NULL_TREE; | |
541 | ||
542 | abb = bb; | |
726a989a | 543 | agsi = gsi; |
6de9cd9a DN |
544 | while (1) |
545 | { | |
d9334061 GS |
546 | tree tmp_a = NULL_TREE; |
547 | tree tmp_m = NULL_TREE; | |
726a989a | 548 | gsi_next (&agsi); |
6de9cd9a | 549 | |
726a989a | 550 | while (gsi_end_p (agsi)) |
6de9cd9a | 551 | { |
c5cbcccf ZD |
552 | ass_var = propagate_through_phis (ass_var, single_succ_edge (abb)); |
553 | abb = single_succ (abb); | |
726a989a | 554 | agsi = gsi_start_bb (abb); |
6de9cd9a DN |
555 | } |
556 | ||
726a989a | 557 | stmt = gsi_stmt (agsi); |
6de9cd9a | 558 | |
726a989a | 559 | if (gimple_code (stmt) == GIMPLE_LABEL) |
6de9cd9a DN |
560 | continue; |
561 | ||
726a989a | 562 | if (gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
563 | break; |
564 | ||
ca786352 JJ |
565 | if (gimple_clobber_p (stmt)) |
566 | continue; | |
567 | ||
b5b8b0ac AO |
568 | if (is_gimple_debug (stmt)) |
569 | continue; | |
570 | ||
726a989a | 571 | if (gimple_code (stmt) != GIMPLE_ASSIGN) |
6de9cd9a DN |
572 | return; |
573 | ||
726a989a | 574 | /* This is a gimple assign. */ |
d9334061 | 575 | if (! process_assignment (stmt, gsi, &tmp_m, &tmp_a, &ass_var)) |
6de9cd9a | 576 | return; |
d9334061 GS |
577 | |
578 | if (tmp_a) | |
579 | { | |
fdb8b4c0 | 580 | tree type = TREE_TYPE (tmp_a); |
d9334061 | 581 | if (a) |
fdb8b4c0 | 582 | a = fold_build2 (PLUS_EXPR, type, fold_convert (type, a), tmp_a); |
d9334061 GS |
583 | else |
584 | a = tmp_a; | |
585 | } | |
586 | if (tmp_m) | |
587 | { | |
fdb8b4c0 | 588 | tree type = TREE_TYPE (tmp_m); |
d9334061 | 589 | if (m) |
fdb8b4c0 | 590 | m = fold_build2 (MULT_EXPR, type, fold_convert (type, m), tmp_m); |
d9334061 GS |
591 | else |
592 | m = tmp_m; | |
593 | ||
594 | if (a) | |
fdb8b4c0 | 595 | a = fold_build2 (MULT_EXPR, type, fold_convert (type, a), tmp_m); |
d9334061 | 596 | } |
6de9cd9a DN |
597 | } |
598 | ||
b89e96ac | 599 | /* See if this is a tail call we can handle. */ |
726a989a | 600 | ret_var = gimple_return_retval (stmt); |
6de9cd9a DN |
601 | |
602 | /* We may proceed if there either is no return value, or the return value | |
603 | is identical to the call's return. */ | |
604 | if (ret_var | |
605 | && (ret_var != ass_var)) | |
606 | return; | |
607 | ||
4b5b9613 RH |
608 | /* If this is not a tail recursive call, we cannot handle addends or |
609 | multiplicands. */ | |
610 | if (!tail_recursion && (m || a)) | |
611 | return; | |
612 | ||
6b00d7dd JJ |
613 | /* For pointers only allow additions. */ |
614 | if (m && POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))) | |
615 | return; | |
616 | ||
e1111e8e | 617 | nw = XNEW (struct tailcall); |
6de9cd9a | 618 | |
726a989a | 619 | nw->call_gsi = gsi; |
6de9cd9a DN |
620 | |
621 | nw->tail_recursion = tail_recursion; | |
622 | ||
623 | nw->mult = m; | |
624 | nw->add = a; | |
625 | ||
626 | nw->next = *ret; | |
627 | *ret = nw; | |
628 | } | |
629 | ||
726a989a | 630 | /* Helper to insert PHI_ARGH to the phi of VAR in the destination of edge E. */ |
6de9cd9a DN |
631 | |
632 | static void | |
726a989a RB |
633 | add_successor_phi_arg (edge e, tree var, tree phi_arg) |
634 | { | |
635 | gimple_stmt_iterator gsi; | |
636 | ||
637 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
638 | if (PHI_RESULT (gsi_stmt (gsi)) == var) | |
639 | break; | |
640 | ||
641 | gcc_assert (!gsi_end_p (gsi)); | |
9e227d60 | 642 | add_phi_arg (gsi_stmt (gsi), phi_arg, e, UNKNOWN_LOCATION); |
726a989a RB |
643 | } |
644 | ||
645 | /* Creates a GIMPLE statement which computes the operation specified by | |
c1781047 JJ |
646 | CODE, ACC and OP1 to a new variable with name LABEL and inserts the |
647 | statement in the position specified by GSI. Returns the | |
726a989a RB |
648 | tree node of the statement's result. */ |
649 | ||
650 | static tree | |
b8698a0f | 651 | adjust_return_value_with_ops (enum tree_code code, const char *label, |
9efc83f4 | 652 | tree acc, tree op1, gimple_stmt_iterator gsi) |
6de9cd9a | 653 | { |
726a989a | 654 | |
6de9cd9a | 655 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl)); |
83d5977e | 656 | tree result = make_temp_ssa_name (ret_type, NULL, label); |
9efc83f4 | 657 | gimple stmt; |
726a989a | 658 | |
6b00d7dd JJ |
659 | if (POINTER_TYPE_P (ret_type)) |
660 | { | |
661 | gcc_assert (code == PLUS_EXPR && TREE_TYPE (acc) == sizetype); | |
662 | code = POINTER_PLUS_EXPR; | |
663 | } | |
664 | if (types_compatible_p (TREE_TYPE (acc), TREE_TYPE (op1)) | |
665 | && code != POINTER_PLUS_EXPR) | |
83d5977e | 666 | stmt = gimple_build_assign_with_ops (code, result, acc, op1); |
9efc83f4 RG |
667 | else |
668 | { | |
6b00d7dd JJ |
669 | tree tem; |
670 | if (code == POINTER_PLUS_EXPR) | |
671 | tem = fold_build2 (code, TREE_TYPE (op1), op1, acc); | |
672 | else | |
673 | tem = fold_build2 (code, TREE_TYPE (op1), | |
674 | fold_convert (TREE_TYPE (op1), acc), op1); | |
675 | tree rhs = fold_convert (ret_type, tem); | |
9efc83f4 | 676 | rhs = force_gimple_operand_gsi (&gsi, rhs, |
c1781047 | 677 | false, NULL, true, GSI_SAME_STMT); |
83d5977e | 678 | stmt = gimple_build_assign (result, rhs); |
9efc83f4 RG |
679 | } |
680 | ||
9efc83f4 | 681 | gsi_insert_before (&gsi, stmt, GSI_NEW_STMT); |
726a989a RB |
682 | return result; |
683 | } | |
684 | ||
b8698a0f | 685 | /* Creates a new GIMPLE statement that adjusts the value of accumulator ACC by |
726a989a RB |
686 | the computation specified by CODE and OP1 and insert the statement |
687 | at the position specified by GSI as a new statement. Returns new SSA name | |
688 | of updated accumulator. */ | |
689 | ||
690 | static tree | |
691 | update_accumulator_with_ops (enum tree_code code, tree acc, tree op1, | |
692 | gimple_stmt_iterator gsi) | |
693 | { | |
9efc83f4 | 694 | gimple stmt; |
070ecdfd | 695 | tree var = copy_ssa_name (acc, NULL); |
9efc83f4 | 696 | if (types_compatible_p (TREE_TYPE (acc), TREE_TYPE (op1))) |
070ecdfd | 697 | stmt = gimple_build_assign_with_ops (code, var, acc, op1); |
9efc83f4 RG |
698 | else |
699 | { | |
700 | tree rhs = fold_convert (TREE_TYPE (acc), | |
701 | fold_build2 (code, | |
702 | TREE_TYPE (op1), | |
703 | fold_convert (TREE_TYPE (op1), acc), | |
704 | op1)); | |
705 | rhs = force_gimple_operand_gsi (&gsi, rhs, | |
706 | false, NULL, false, GSI_CONTINUE_LINKING); | |
070ecdfd | 707 | stmt = gimple_build_assign (var, rhs); |
9efc83f4 | 708 | } |
726a989a RB |
709 | gsi_insert_after (&gsi, stmt, GSI_NEW_STMT); |
710 | return var; | |
711 | } | |
712 | ||
713 | /* Adjust the accumulator values according to A and M after GSI, and update | |
714 | the phi nodes on edge BACK. */ | |
715 | ||
716 | static void | |
717 | adjust_accumulator_values (gimple_stmt_iterator gsi, tree m, tree a, edge back) | |
718 | { | |
d9334061 GS |
719 | tree var, a_acc_arg, m_acc_arg; |
720 | ||
721 | if (m) | |
722 | m = force_gimple_operand_gsi (&gsi, m, true, NULL, true, GSI_SAME_STMT); | |
723 | if (a) | |
724 | a = force_gimple_operand_gsi (&gsi, a, true, NULL, true, GSI_SAME_STMT); | |
6de9cd9a | 725 | |
d9334061 GS |
726 | a_acc_arg = a_acc; |
727 | m_acc_arg = m_acc; | |
6de9cd9a DN |
728 | if (a) |
729 | { | |
730 | if (m_acc) | |
731 | { | |
732 | if (integer_onep (a)) | |
733 | var = m_acc; | |
734 | else | |
726a989a | 735 | var = adjust_return_value_with_ops (MULT_EXPR, "acc_tmp", m_acc, |
9efc83f4 | 736 | a, gsi); |
6de9cd9a DN |
737 | } |
738 | else | |
739 | var = a; | |
740 | ||
726a989a | 741 | a_acc_arg = update_accumulator_with_ops (PLUS_EXPR, a_acc, var, gsi); |
6de9cd9a DN |
742 | } |
743 | ||
744 | if (m) | |
726a989a | 745 | m_acc_arg = update_accumulator_with_ops (MULT_EXPR, m_acc, m, gsi); |
6de9cd9a DN |
746 | |
747 | if (a_acc) | |
726a989a | 748 | add_successor_phi_arg (back, a_acc, a_acc_arg); |
6de9cd9a DN |
749 | |
750 | if (m_acc) | |
726a989a | 751 | add_successor_phi_arg (back, m_acc, m_acc_arg); |
6de9cd9a DN |
752 | } |
753 | ||
1ea7e6ad | 754 | /* Adjust value of the return at the end of BB according to M and A |
6de9cd9a DN |
755 | accumulators. */ |
756 | ||
757 | static void | |
758 | adjust_return_value (basic_block bb, tree m, tree a) | |
759 | { | |
726a989a RB |
760 | tree retval; |
761 | gimple ret_stmt = gimple_seq_last_stmt (bb_seq (bb)); | |
762 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
6de9cd9a | 763 | |
726a989a | 764 | gcc_assert (gimple_code (ret_stmt) == GIMPLE_RETURN); |
6de9cd9a | 765 | |
726a989a RB |
766 | retval = gimple_return_retval (ret_stmt); |
767 | if (!retval || retval == error_mark_node) | |
6de9cd9a DN |
768 | return; |
769 | ||
6de9cd9a | 770 | if (m) |
726a989a | 771 | retval = adjust_return_value_with_ops (MULT_EXPR, "mul_tmp", m_acc, retval, |
9efc83f4 | 772 | gsi); |
6de9cd9a | 773 | if (a) |
726a989a | 774 | retval = adjust_return_value_with_ops (PLUS_EXPR, "acc_tmp", a_acc, retval, |
9efc83f4 | 775 | gsi); |
726a989a | 776 | gimple_return_set_retval (ret_stmt, retval); |
f430bae8 | 777 | update_stmt (ret_stmt); |
6de9cd9a DN |
778 | } |
779 | ||
23504559 JH |
780 | /* Subtract COUNT and FREQUENCY from the basic block and it's |
781 | outgoing edge. */ | |
782 | static void | |
783 | decrease_profile (basic_block bb, gcov_type count, int frequency) | |
784 | { | |
785 | edge e; | |
786 | bb->count -= count; | |
787 | if (bb->count < 0) | |
788 | bb->count = 0; | |
789 | bb->frequency -= frequency; | |
790 | if (bb->frequency < 0) | |
791 | bb->frequency = 0; | |
792 | if (!single_succ_p (bb)) | |
793 | { | |
794 | gcc_assert (!EDGE_COUNT (bb->succs)); | |
795 | return; | |
796 | } | |
797 | e = single_succ_edge (bb); | |
798 | e->count -= count; | |
799 | if (e->count < 0) | |
800 | e->count = 0; | |
801 | } | |
802 | ||
016925bc ZD |
803 | /* Returns true if argument PARAM of the tail recursive call needs to be copied |
804 | when the call is eliminated. */ | |
805 | ||
806 | static bool | |
807 | arg_needs_copy_p (tree param) | |
808 | { | |
809 | tree def; | |
810 | ||
5f564b8f | 811 | if (!is_gimple_reg (param)) |
016925bc | 812 | return false; |
b8698a0f | 813 | |
016925bc | 814 | /* Parameters that are only defined but never used need not be copied. */ |
32244553 | 815 | def = ssa_default_def (cfun, param); |
016925bc ZD |
816 | if (!def) |
817 | return false; | |
818 | ||
819 | return true; | |
820 | } | |
821 | ||
6de9cd9a DN |
822 | /* Eliminates tail call described by T. TMP_VARS is a list of |
823 | temporary variables used to copy the function arguments. */ | |
824 | ||
825 | static void | |
826 | eliminate_tail_call (struct tailcall *t) | |
827 | { | |
726a989a RB |
828 | tree param, rslt; |
829 | gimple stmt, call; | |
5039610b | 830 | tree arg; |
726a989a | 831 | size_t idx; |
6de9cd9a DN |
832 | basic_block bb, first; |
833 | edge e; | |
726a989a RB |
834 | gimple phi; |
835 | gimple_stmt_iterator gsi; | |
836 | gimple orig_stmt; | |
6de9cd9a | 837 | |
726a989a RB |
838 | stmt = orig_stmt = gsi_stmt (t->call_gsi); |
839 | bb = gsi_bb (t->call_gsi); | |
6de9cd9a DN |
840 | |
841 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
842 | { | |
843 | fprintf (dump_file, "Eliminated tail recursion in bb %d : ", | |
844 | bb->index); | |
726a989a | 845 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
6de9cd9a DN |
846 | fprintf (dump_file, "\n"); |
847 | } | |
848 | ||
726a989a | 849 | gcc_assert (is_gimple_call (stmt)); |
6de9cd9a | 850 | |
fefa31b5 | 851 | first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
6de9cd9a | 852 | |
726a989a | 853 | /* Remove the code after call_gsi that will become unreachable. The |
8d3d51b5 ZD |
854 | possibly unreachable code in other blocks is removed later in |
855 | cfg cleanup. */ | |
726a989a RB |
856 | gsi = t->call_gsi; |
857 | gsi_next (&gsi); | |
858 | while (!gsi_end_p (gsi)) | |
8d3d51b5 | 859 | { |
726a989a | 860 | gimple t = gsi_stmt (gsi); |
8d3d51b5 ZD |
861 | /* Do not remove the return statement, so that redirect_edge_and_branch |
862 | sees how the block ends. */ | |
726a989a | 863 | if (gimple_code (t) == GIMPLE_RETURN) |
8d3d51b5 ZD |
864 | break; |
865 | ||
726a989a | 866 | gsi_remove (&gsi, true); |
87527e4b | 867 | release_defs (t); |
8d3d51b5 ZD |
868 | } |
869 | ||
23504559 | 870 | /* Number of executions of function has reduced by the tailcall. */ |
726a989a | 871 | e = single_succ_edge (gsi_bb (t->call_gsi)); |
fefa31b5 DM |
872 | decrease_profile (EXIT_BLOCK_PTR_FOR_FN (cfun), e->count, EDGE_FREQUENCY (e)); |
873 | decrease_profile (ENTRY_BLOCK_PTR_FOR_FN (cfun), e->count, | |
874 | EDGE_FREQUENCY (e)); | |
875 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
23504559 JH |
876 | decrease_profile (e->dest, e->count, EDGE_FREQUENCY (e)); |
877 | ||
6de9cd9a | 878 | /* Replace the call by a jump to the start of function. */ |
726a989a RB |
879 | e = redirect_edge_and_branch (single_succ_edge (gsi_bb (t->call_gsi)), |
880 | first); | |
1e128c5f | 881 | gcc_assert (e); |
726a989a | 882 | PENDING_STMT (e) = NULL; |
6de9cd9a | 883 | |
016925bc ZD |
884 | /* Add phi node entries for arguments. The ordering of the phi nodes should |
885 | be the same as the ordering of the arguments. */ | |
6de9cd9a | 886 | for (param = DECL_ARGUMENTS (current_function_decl), |
726a989a | 887 | idx = 0, gsi = gsi_start_phis (first); |
6de9cd9a | 888 | param; |
910ad8de | 889 | param = DECL_CHAIN (param), idx++) |
6de9cd9a | 890 | { |
016925bc | 891 | if (!arg_needs_copy_p (param)) |
6de9cd9a | 892 | continue; |
726a989a RB |
893 | |
894 | arg = gimple_call_arg (stmt, idx); | |
895 | phi = gsi_stmt (gsi); | |
016925bc | 896 | gcc_assert (param == SSA_NAME_VAR (PHI_RESULT (phi))); |
6de9cd9a | 897 | |
9e227d60 | 898 | add_phi_arg (phi, arg, e, gimple_location (stmt)); |
726a989a | 899 | gsi_next (&gsi); |
6de9cd9a DN |
900 | } |
901 | ||
902 | /* Update the values of accumulators. */ | |
726a989a | 903 | adjust_accumulator_values (t->call_gsi, t->mult, t->add, e); |
6de9cd9a | 904 | |
726a989a RB |
905 | call = gsi_stmt (t->call_gsi); |
906 | rslt = gimple_call_lhs (call); | |
907 | if (rslt != NULL_TREE) | |
6de9cd9a | 908 | { |
6de9cd9a DN |
909 | /* Result of the call will no longer be defined. So adjust the |
910 | SSA_NAME_DEF_STMT accordingly. */ | |
726a989a | 911 | SSA_NAME_DEF_STMT (rslt) = gimple_build_nop (); |
6de9cd9a DN |
912 | } |
913 | ||
726a989a | 914 | gsi_remove (&t->call_gsi, true); |
87527e4b | 915 | release_defs (call); |
6de9cd9a DN |
916 | } |
917 | ||
918 | /* Optimizes the tailcall described by T. If OPT_TAILCALLS is true, also | |
919 | mark the tailcalls for the sibcall optimization. */ | |
920 | ||
921 | static bool | |
922 | optimize_tail_call (struct tailcall *t, bool opt_tailcalls) | |
923 | { | |
924 | if (t->tail_recursion) | |
925 | { | |
926 | eliminate_tail_call (t); | |
927 | return true; | |
928 | } | |
929 | ||
930 | if (opt_tailcalls) | |
931 | { | |
726a989a | 932 | gimple stmt = gsi_stmt (t->call_gsi); |
6de9cd9a | 933 | |
726a989a | 934 | gimple_call_set_tail (stmt, true); |
e2f0f5f7 | 935 | cfun->tail_call_marked = true; |
6de9cd9a DN |
936 | if (dump_file && (dump_flags & TDF_DETAILS)) |
937 | { | |
938 | fprintf (dump_file, "Found tail call "); | |
726a989a RB |
939 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
940 | fprintf (dump_file, " in bb %i\n", (gsi_bb (t->call_gsi))->index); | |
6de9cd9a DN |
941 | } |
942 | } | |
943 | ||
944 | return false; | |
945 | } | |
946 | ||
726a989a RB |
947 | /* Creates a tail-call accumulator of the same type as the return type of the |
948 | current function. LABEL is the name used to creating the temporary | |
949 | variable for the accumulator. The accumulator will be inserted in the | |
950 | phis of a basic block BB with single predecessor with an initial value | |
951 | INIT converted to the current function return type. */ | |
952 | ||
953 | static tree | |
954 | create_tailcall_accumulator (const char *label, basic_block bb, tree init) | |
955 | { | |
956 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl)); | |
6b00d7dd JJ |
957 | if (POINTER_TYPE_P (ret_type)) |
958 | ret_type = sizetype; | |
959 | ||
83d5977e | 960 | tree tmp = make_temp_ssa_name (ret_type, NULL, label); |
726a989a RB |
961 | gimple phi; |
962 | ||
726a989a RB |
963 | phi = create_phi_node (tmp, bb); |
964 | /* RET_TYPE can be a float when -ffast-maths is enabled. */ | |
f5045c96 | 965 | add_phi_arg (phi, fold_convert (ret_type, init), single_pred_edge (bb), |
9e227d60 | 966 | UNKNOWN_LOCATION); |
726a989a RB |
967 | return PHI_RESULT (phi); |
968 | } | |
b8698a0f | 969 | |
6de9cd9a DN |
970 | /* Optimizes tail calls in the function, turning the tail recursion |
971 | into iteration. */ | |
972 | ||
1994bfea | 973 | static unsigned int |
6de9cd9a DN |
974 | tree_optimize_tail_calls_1 (bool opt_tailcalls) |
975 | { | |
976 | edge e; | |
977 | bool phis_constructed = false; | |
978 | struct tailcall *tailcalls = NULL, *act, *next; | |
979 | bool changed = false; | |
fefa31b5 | 980 | basic_block first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
726a989a RB |
981 | tree param; |
982 | gimple stmt; | |
628f6a4e | 983 | edge_iterator ei; |
6de9cd9a DN |
984 | |
985 | if (!suitable_for_tail_opt_p ()) | |
1994bfea | 986 | return 0; |
6de9cd9a DN |
987 | if (opt_tailcalls) |
988 | opt_tailcalls = suitable_for_tail_call_opt_p (); | |
989 | ||
fefa31b5 | 990 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) |
6de9cd9a DN |
991 | { |
992 | /* Only traverse the normal exits, i.e. those that end with return | |
993 | statement. */ | |
994 | stmt = last_stmt (e->src); | |
995 | ||
996 | if (stmt | |
726a989a | 997 | && gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
998 | find_tail_calls (e->src, &tailcalls); |
999 | } | |
1000 | ||
1001 | /* Construct the phi nodes and accumulators if necessary. */ | |
1002 | a_acc = m_acc = NULL_TREE; | |
1003 | for (act = tailcalls; act; act = act->next) | |
1004 | { | |
1005 | if (!act->tail_recursion) | |
1006 | continue; | |
1007 | ||
1008 | if (!phis_constructed) | |
1009 | { | |
5006671f RG |
1010 | /* Ensure that there is only one predecessor of the block |
1011 | or if there are existing degenerate PHI nodes. */ | |
1012 | if (!single_pred_p (first) | |
1013 | || !gimple_seq_empty_p (phi_nodes (first))) | |
fefa31b5 DM |
1014 | first = |
1015 | split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
6de9cd9a DN |
1016 | |
1017 | /* Copy the args if needed. */ | |
1018 | for (param = DECL_ARGUMENTS (current_function_decl); | |
1019 | param; | |
910ad8de | 1020 | param = DECL_CHAIN (param)) |
016925bc ZD |
1021 | if (arg_needs_copy_p (param)) |
1022 | { | |
32244553 | 1023 | tree name = ssa_default_def (cfun, param); |
016925bc | 1024 | tree new_name = make_ssa_name (param, SSA_NAME_DEF_STMT (name)); |
726a989a | 1025 | gimple phi; |
016925bc | 1026 | |
32244553 | 1027 | set_ssa_default_def (cfun, param, new_name); |
016925bc | 1028 | phi = create_phi_node (name, first); |
b8698a0f | 1029 | add_phi_arg (phi, new_name, single_pred_edge (first), |
9e227d60 | 1030 | EXPR_LOCATION (param)); |
016925bc | 1031 | } |
6de9cd9a DN |
1032 | phis_constructed = true; |
1033 | } | |
1034 | ||
1035 | if (act->add && !a_acc) | |
726a989a RB |
1036 | a_acc = create_tailcall_accumulator ("add_acc", first, |
1037 | integer_zero_node); | |
6de9cd9a DN |
1038 | |
1039 | if (act->mult && !m_acc) | |
726a989a RB |
1040 | m_acc = create_tailcall_accumulator ("mult_acc", first, |
1041 | integer_one_node); | |
016925bc ZD |
1042 | } |
1043 | ||
1400c8e5 ZD |
1044 | if (a_acc || m_acc) |
1045 | { | |
1046 | /* When the tail call elimination using accumulators is performed, | |
1047 | statements adding the accumulated value are inserted at all exits. | |
1048 | This turns all other tail calls to non-tail ones. */ | |
1049 | opt_tailcalls = false; | |
1050 | } | |
1051 | ||
6de9cd9a DN |
1052 | for (; tailcalls; tailcalls = next) |
1053 | { | |
1054 | next = tailcalls->next; | |
1055 | changed |= optimize_tail_call (tailcalls, opt_tailcalls); | |
1056 | free (tailcalls); | |
1057 | } | |
1058 | ||
1059 | if (a_acc || m_acc) | |
1060 | { | |
1061 | /* Modify the remaining return statements. */ | |
fefa31b5 | 1062 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) |
6de9cd9a DN |
1063 | { |
1064 | stmt = last_stmt (e->src); | |
1065 | ||
1066 | if (stmt | |
726a989a | 1067 | && gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
1068 | adjust_return_value (e->src, m_acc, a_acc); |
1069 | } | |
1070 | } | |
1071 | ||
1072 | if (changed) | |
0d5049b2 RB |
1073 | { |
1074 | /* We may have created new loops. Make them magically appear. */ | |
726338f4 | 1075 | loops_state_set (LOOPS_NEED_FIXUP); |
0d5049b2 RB |
1076 | free_dominance_info (CDI_DOMINATORS); |
1077 | } | |
016925bc | 1078 | |
824f71b9 RG |
1079 | /* Add phi nodes for the virtual operands defined in the function to the |
1080 | header of the loop created by tail recursion elimination. Do so | |
1081 | by triggering the SSA renamer. */ | |
016925bc | 1082 | if (phis_constructed) |
525174a2 | 1083 | mark_virtual_operands_for_renaming (cfun); |
824f71b9 | 1084 | |
1994bfea JH |
1085 | if (changed) |
1086 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; | |
1087 | return 0; | |
6de9cd9a DN |
1088 | } |
1089 | ||
6de9cd9a DN |
1090 | static bool |
1091 | gate_tail_calls (void) | |
1092 | { | |
6fb5fa3c | 1093 | return flag_optimize_sibling_calls != 0 && dbg_cnt (tail_call); |
6de9cd9a DN |
1094 | } |
1095 | ||
c2924966 | 1096 | static unsigned int |
6de9cd9a DN |
1097 | execute_tail_calls (void) |
1098 | { | |
1994bfea | 1099 | return tree_optimize_tail_calls_1 (true); |
6de9cd9a DN |
1100 | } |
1101 | ||
27a4cd48 DM |
1102 | namespace { |
1103 | ||
1104 | const pass_data pass_data_tail_recursion = | |
6de9cd9a | 1105 | { |
27a4cd48 DM |
1106 | GIMPLE_PASS, /* type */ |
1107 | "tailr", /* name */ | |
1108 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
1109 | TV_NONE, /* tv_id */ |
1110 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1111 | 0, /* properties_provided */ | |
1112 | 0, /* properties_destroyed */ | |
1113 | 0, /* todo_flags_start */ | |
3bea341f | 1114 | 0, /* todo_flags_finish */ |
6de9cd9a DN |
1115 | }; |
1116 | ||
27a4cd48 DM |
1117 | class pass_tail_recursion : public gimple_opt_pass |
1118 | { | |
1119 | public: | |
c3284718 RS |
1120 | pass_tail_recursion (gcc::context *ctxt) |
1121 | : gimple_opt_pass (pass_data_tail_recursion, ctxt) | |
27a4cd48 DM |
1122 | {} |
1123 | ||
1124 | /* opt_pass methods: */ | |
65d3284b | 1125 | opt_pass * clone () { return new pass_tail_recursion (m_ctxt); } |
1a3d085c | 1126 | virtual bool gate (function *) { return gate_tail_calls (); } |
be55bfe6 TS |
1127 | virtual unsigned int execute (function *) |
1128 | { | |
1129 | return tree_optimize_tail_calls_1 (false); | |
1130 | } | |
27a4cd48 DM |
1131 | |
1132 | }; // class pass_tail_recursion | |
1133 | ||
1134 | } // anon namespace | |
1135 | ||
1136 | gimple_opt_pass * | |
1137 | make_pass_tail_recursion (gcc::context *ctxt) | |
1138 | { | |
1139 | return new pass_tail_recursion (ctxt); | |
1140 | } | |
1141 | ||
1142 | namespace { | |
1143 | ||
1144 | const pass_data pass_data_tail_calls = | |
6de9cd9a | 1145 | { |
27a4cd48 DM |
1146 | GIMPLE_PASS, /* type */ |
1147 | "tailc", /* name */ | |
1148 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
1149 | TV_NONE, /* tv_id */ |
1150 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1151 | 0, /* properties_provided */ | |
1152 | 0, /* properties_destroyed */ | |
1153 | 0, /* todo_flags_start */ | |
3bea341f | 1154 | 0, /* todo_flags_finish */ |
6de9cd9a | 1155 | }; |
27a4cd48 DM |
1156 | |
1157 | class pass_tail_calls : public gimple_opt_pass | |
1158 | { | |
1159 | public: | |
c3284718 RS |
1160 | pass_tail_calls (gcc::context *ctxt) |
1161 | : gimple_opt_pass (pass_data_tail_calls, ctxt) | |
27a4cd48 DM |
1162 | {} |
1163 | ||
1164 | /* opt_pass methods: */ | |
1a3d085c | 1165 | virtual bool gate (function *) { return gate_tail_calls (); } |
be55bfe6 | 1166 | virtual unsigned int execute (function *) { return execute_tail_calls (); } |
27a4cd48 DM |
1167 | |
1168 | }; // class pass_tail_calls | |
1169 | ||
1170 | } // anon namespace | |
1171 | ||
1172 | gimple_opt_pass * | |
1173 | make_pass_tail_calls (gcc::context *ctxt) | |
1174 | { | |
1175 | return new pass_tail_calls (ctxt); | |
1176 | } |