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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 | |
538dd0b7 | 283 | process_assignment (gassign *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; | |
538dd0b7 | 404 | gphi_iterator gsi; |
b8698a0f | 405 | |
726a989a RB |
406 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
407 | { | |
538dd0b7 | 408 | gphi *phi = gsi.phi (); |
726a989a RB |
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 | 421 | tree ass_var = NULL_TREE, ret_var, func, param; |
538dd0b7 DM |
422 | gimple stmt; |
423 | gcall *call = NULL; | |
726a989a | 424 | gimple_stmt_iterator gsi, agsi; |
6de9cd9a DN |
425 | bool tail_recursion; |
426 | struct tailcall *nw; | |
427 | edge e; | |
428 | tree m, a; | |
429 | basic_block abb; | |
726a989a | 430 | size_t idx; |
12de6355 | 431 | tree var; |
6de9cd9a | 432 | |
c5cbcccf | 433 | if (!single_succ_p (bb)) |
6de9cd9a DN |
434 | return; |
435 | ||
726a989a | 436 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
6de9cd9a | 437 | { |
726a989a | 438 | stmt = gsi_stmt (gsi); |
6de9cd9a | 439 | |
ca786352 | 440 | /* Ignore labels, returns, clobbers and debug stmts. */ |
e106efc7 RG |
441 | if (gimple_code (stmt) == GIMPLE_LABEL |
442 | || gimple_code (stmt) == GIMPLE_RETURN | |
ca786352 | 443 | || gimple_clobber_p (stmt) |
e106efc7 | 444 | || is_gimple_debug (stmt)) |
6de9cd9a DN |
445 | continue; |
446 | ||
6de9cd9a | 447 | /* Check for a call. */ |
726a989a | 448 | if (is_gimple_call (stmt)) |
6de9cd9a | 449 | { |
538dd0b7 DM |
450 | call = as_a <gcall *> (stmt); |
451 | ass_var = gimple_call_lhs (call); | |
726a989a | 452 | break; |
6de9cd9a DN |
453 | } |
454 | ||
5006671f RG |
455 | /* If the statement references memory or volatile operands, fail. */ |
456 | if (gimple_references_memory_p (stmt) | |
457 | || gimple_has_volatile_ops (stmt)) | |
6de9cd9a DN |
458 | return; |
459 | } | |
460 | ||
726a989a | 461 | if (gsi_end_p (gsi)) |
6de9cd9a | 462 | { |
628f6a4e | 463 | edge_iterator ei; |
6de9cd9a | 464 | /* Recurse to the predecessors. */ |
628f6a4e | 465 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
466 | find_tail_calls (e->src, ret); |
467 | ||
468 | return; | |
469 | } | |
470 | ||
b8698a0f | 471 | /* If the LHS of our call is not just a simple register, we can't |
bd42a56b MM |
472 | transform this into a tail or sibling call. This situation happens, |
473 | in (e.g.) "*p = foo()" where foo returns a struct. In this case | |
474 | we won't have a temporary here, but we need to carry out the side | |
475 | effect anyway, so tailcall is impossible. | |
476 | ||
477 | ??? In some situations (when the struct is returned in memory via | |
478 | invisible argument) we could deal with this, e.g. by passing 'p' | |
479 | itself as that argument to foo, but it's too early to do this here, | |
480 | and expand_call() will not handle it anyway. If it ever can, then | |
481 | we need to revisit this here, to allow that situation. */ | |
482 | if (ass_var && !is_gimple_reg (ass_var)) | |
483 | return; | |
484 | ||
6de9cd9a DN |
485 | /* We found the call, check whether it is suitable. */ |
486 | tail_recursion = false; | |
726a989a | 487 | func = gimple_call_fndecl (call); |
16022041 RS |
488 | if (func |
489 | && !DECL_BUILT_IN (func) | |
490 | && recursive_call_p (current_function_decl, func)) | |
6de9cd9a | 491 | { |
12de6355 | 492 | tree arg; |
d086d311 | 493 | |
726a989a RB |
494 | for (param = DECL_ARGUMENTS (func), idx = 0; |
495 | param && idx < gimple_call_num_args (call); | |
910ad8de | 496 | param = DECL_CHAIN (param), idx ++) |
6de9cd9a | 497 | { |
726a989a | 498 | arg = gimple_call_arg (call, idx); |
14de86fa ZD |
499 | if (param != arg) |
500 | { | |
501 | /* Make sure there are no problems with copying. The parameter | |
6de9cd9a DN |
502 | have a copyable type and the two arguments must have reasonably |
503 | equivalent types. The latter requirement could be relaxed if | |
504 | we emitted a suitable type conversion statement. */ | |
14de86fa | 505 | if (!is_gimple_reg_type (TREE_TYPE (param)) |
f4088621 | 506 | || !useless_type_conversion_p (TREE_TYPE (param), |
726a989a | 507 | TREE_TYPE (arg))) |
14de86fa ZD |
508 | break; |
509 | ||
510 | /* The parameter should be a real operand, so that phi node | |
511 | created for it at the start of the function has the meaning | |
512 | of copying the value. This test implies is_gimple_reg_type | |
513 | from the previous condition, however this one could be | |
514 | relaxed by being more careful with copying the new value | |
726a989a | 515 | of the parameter (emitting appropriate GIMPLE_ASSIGN and |
14de86fa ZD |
516 | updating the virtual operands). */ |
517 | if (!is_gimple_reg (param)) | |
518 | break; | |
519 | } | |
6de9cd9a | 520 | } |
726a989a | 521 | if (idx == gimple_call_num_args (call) && !param) |
6de9cd9a | 522 | tail_recursion = true; |
12de6355 | 523 | } |
d086d311 | 524 | |
12de6355 RG |
525 | /* Make sure the tail invocation of this function does not refer |
526 | to local variables. */ | |
824f71b9 | 527 | FOR_EACH_LOCAL_DECL (cfun, idx, var) |
12de6355 | 528 | { |
4e708ff7 RG |
529 | if (TREE_CODE (var) != PARM_DECL |
530 | && auto_var_in_fn_p (var, cfun->decl) | |
52c307ba RG |
531 | && (ref_maybe_used_by_stmt_p (call, var) |
532 | || call_may_clobber_ref_p (call, var))) | |
12de6355 | 533 | return; |
6de9cd9a DN |
534 | } |
535 | ||
536 | /* Now check the statements after the call. None of them has virtual | |
537 | operands, so they may only depend on the call through its return | |
538 | value. The return value should also be dependent on each of them, | |
539 | since we are running after dce. */ | |
540 | m = NULL_TREE; | |
541 | a = NULL_TREE; | |
542 | ||
543 | abb = bb; | |
726a989a | 544 | agsi = gsi; |
6de9cd9a DN |
545 | while (1) |
546 | { | |
d9334061 GS |
547 | tree tmp_a = NULL_TREE; |
548 | tree tmp_m = NULL_TREE; | |
726a989a | 549 | gsi_next (&agsi); |
6de9cd9a | 550 | |
726a989a | 551 | while (gsi_end_p (agsi)) |
6de9cd9a | 552 | { |
c5cbcccf ZD |
553 | ass_var = propagate_through_phis (ass_var, single_succ_edge (abb)); |
554 | abb = single_succ (abb); | |
726a989a | 555 | agsi = gsi_start_bb (abb); |
6de9cd9a DN |
556 | } |
557 | ||
726a989a | 558 | stmt = gsi_stmt (agsi); |
6de9cd9a | 559 | |
726a989a | 560 | if (gimple_code (stmt) == GIMPLE_LABEL) |
6de9cd9a DN |
561 | continue; |
562 | ||
726a989a | 563 | if (gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
564 | break; |
565 | ||
ca786352 JJ |
566 | if (gimple_clobber_p (stmt)) |
567 | continue; | |
568 | ||
b5b8b0ac AO |
569 | if (is_gimple_debug (stmt)) |
570 | continue; | |
571 | ||
726a989a | 572 | if (gimple_code (stmt) != GIMPLE_ASSIGN) |
6de9cd9a DN |
573 | return; |
574 | ||
726a989a | 575 | /* This is a gimple assign. */ |
538dd0b7 DM |
576 | if (! process_assignment (as_a <gassign *> (stmt), gsi, &tmp_m, |
577 | &tmp_a, &ass_var)) | |
6de9cd9a | 578 | return; |
d9334061 GS |
579 | |
580 | if (tmp_a) | |
581 | { | |
fdb8b4c0 | 582 | tree type = TREE_TYPE (tmp_a); |
d9334061 | 583 | if (a) |
fdb8b4c0 | 584 | a = fold_build2 (PLUS_EXPR, type, fold_convert (type, a), tmp_a); |
d9334061 GS |
585 | else |
586 | a = tmp_a; | |
587 | } | |
588 | if (tmp_m) | |
589 | { | |
fdb8b4c0 | 590 | tree type = TREE_TYPE (tmp_m); |
d9334061 | 591 | if (m) |
fdb8b4c0 | 592 | m = fold_build2 (MULT_EXPR, type, fold_convert (type, m), tmp_m); |
d9334061 GS |
593 | else |
594 | m = tmp_m; | |
595 | ||
596 | if (a) | |
fdb8b4c0 | 597 | a = fold_build2 (MULT_EXPR, type, fold_convert (type, a), tmp_m); |
d9334061 | 598 | } |
6de9cd9a DN |
599 | } |
600 | ||
b89e96ac | 601 | /* See if this is a tail call we can handle. */ |
538dd0b7 | 602 | ret_var = gimple_return_retval (as_a <greturn *> (stmt)); |
6de9cd9a DN |
603 | |
604 | /* We may proceed if there either is no return value, or the return value | |
605 | is identical to the call's return. */ | |
606 | if (ret_var | |
607 | && (ret_var != ass_var)) | |
608 | return; | |
609 | ||
4b5b9613 RH |
610 | /* If this is not a tail recursive call, we cannot handle addends or |
611 | multiplicands. */ | |
612 | if (!tail_recursion && (m || a)) | |
613 | return; | |
614 | ||
6b00d7dd JJ |
615 | /* For pointers only allow additions. */ |
616 | if (m && POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))) | |
617 | return; | |
618 | ||
e1111e8e | 619 | nw = XNEW (struct tailcall); |
6de9cd9a | 620 | |
726a989a | 621 | nw->call_gsi = gsi; |
6de9cd9a DN |
622 | |
623 | nw->tail_recursion = tail_recursion; | |
624 | ||
625 | nw->mult = m; | |
626 | nw->add = a; | |
627 | ||
628 | nw->next = *ret; | |
629 | *ret = nw; | |
630 | } | |
631 | ||
726a989a | 632 | /* Helper to insert PHI_ARGH to the phi of VAR in the destination of edge E. */ |
6de9cd9a DN |
633 | |
634 | static void | |
726a989a RB |
635 | add_successor_phi_arg (edge e, tree var, tree phi_arg) |
636 | { | |
538dd0b7 | 637 | gphi_iterator gsi; |
726a989a RB |
638 | |
639 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
538dd0b7 | 640 | if (PHI_RESULT (gsi.phi ()) == var) |
726a989a RB |
641 | break; |
642 | ||
643 | gcc_assert (!gsi_end_p (gsi)); | |
538dd0b7 | 644 | add_phi_arg (gsi.phi (), phi_arg, e, UNKNOWN_LOCATION); |
726a989a RB |
645 | } |
646 | ||
647 | /* Creates a GIMPLE statement which computes the operation specified by | |
c1781047 JJ |
648 | CODE, ACC and OP1 to a new variable with name LABEL and inserts the |
649 | statement in the position specified by GSI. Returns the | |
726a989a RB |
650 | tree node of the statement's result. */ |
651 | ||
652 | static tree | |
b8698a0f | 653 | adjust_return_value_with_ops (enum tree_code code, const char *label, |
9efc83f4 | 654 | tree acc, tree op1, gimple_stmt_iterator gsi) |
6de9cd9a | 655 | { |
726a989a | 656 | |
6de9cd9a | 657 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl)); |
83d5977e | 658 | tree result = make_temp_ssa_name (ret_type, NULL, label); |
538dd0b7 | 659 | gassign *stmt; |
726a989a | 660 | |
6b00d7dd JJ |
661 | if (POINTER_TYPE_P (ret_type)) |
662 | { | |
663 | gcc_assert (code == PLUS_EXPR && TREE_TYPE (acc) == sizetype); | |
664 | code = POINTER_PLUS_EXPR; | |
665 | } | |
666 | if (types_compatible_p (TREE_TYPE (acc), TREE_TYPE (op1)) | |
667 | && code != POINTER_PLUS_EXPR) | |
83d5977e | 668 | stmt = gimple_build_assign_with_ops (code, result, acc, op1); |
9efc83f4 RG |
669 | else |
670 | { | |
6b00d7dd JJ |
671 | tree tem; |
672 | if (code == POINTER_PLUS_EXPR) | |
673 | tem = fold_build2 (code, TREE_TYPE (op1), op1, acc); | |
674 | else | |
675 | tem = fold_build2 (code, TREE_TYPE (op1), | |
676 | fold_convert (TREE_TYPE (op1), acc), op1); | |
677 | tree rhs = fold_convert (ret_type, tem); | |
9efc83f4 | 678 | rhs = force_gimple_operand_gsi (&gsi, rhs, |
c1781047 | 679 | false, NULL, true, GSI_SAME_STMT); |
83d5977e | 680 | stmt = gimple_build_assign (result, rhs); |
9efc83f4 RG |
681 | } |
682 | ||
9efc83f4 | 683 | gsi_insert_before (&gsi, stmt, GSI_NEW_STMT); |
726a989a RB |
684 | return result; |
685 | } | |
686 | ||
b8698a0f | 687 | /* Creates a new GIMPLE statement that adjusts the value of accumulator ACC by |
726a989a RB |
688 | the computation specified by CODE and OP1 and insert the statement |
689 | at the position specified by GSI as a new statement. Returns new SSA name | |
690 | of updated accumulator. */ | |
691 | ||
692 | static tree | |
693 | update_accumulator_with_ops (enum tree_code code, tree acc, tree op1, | |
694 | gimple_stmt_iterator gsi) | |
695 | { | |
538dd0b7 | 696 | gassign *stmt; |
070ecdfd | 697 | tree var = copy_ssa_name (acc, NULL); |
9efc83f4 | 698 | if (types_compatible_p (TREE_TYPE (acc), TREE_TYPE (op1))) |
070ecdfd | 699 | stmt = gimple_build_assign_with_ops (code, var, acc, op1); |
9efc83f4 RG |
700 | else |
701 | { | |
702 | tree rhs = fold_convert (TREE_TYPE (acc), | |
703 | fold_build2 (code, | |
704 | TREE_TYPE (op1), | |
705 | fold_convert (TREE_TYPE (op1), acc), | |
706 | op1)); | |
707 | rhs = force_gimple_operand_gsi (&gsi, rhs, | |
708 | false, NULL, false, GSI_CONTINUE_LINKING); | |
070ecdfd | 709 | stmt = gimple_build_assign (var, rhs); |
9efc83f4 | 710 | } |
726a989a RB |
711 | gsi_insert_after (&gsi, stmt, GSI_NEW_STMT); |
712 | return var; | |
713 | } | |
714 | ||
715 | /* Adjust the accumulator values according to A and M after GSI, and update | |
716 | the phi nodes on edge BACK. */ | |
717 | ||
718 | static void | |
719 | adjust_accumulator_values (gimple_stmt_iterator gsi, tree m, tree a, edge back) | |
720 | { | |
d9334061 GS |
721 | tree var, a_acc_arg, m_acc_arg; |
722 | ||
723 | if (m) | |
724 | m = force_gimple_operand_gsi (&gsi, m, true, NULL, true, GSI_SAME_STMT); | |
725 | if (a) | |
726 | a = force_gimple_operand_gsi (&gsi, a, true, NULL, true, GSI_SAME_STMT); | |
6de9cd9a | 727 | |
d9334061 GS |
728 | a_acc_arg = a_acc; |
729 | m_acc_arg = m_acc; | |
6de9cd9a DN |
730 | if (a) |
731 | { | |
732 | if (m_acc) | |
733 | { | |
734 | if (integer_onep (a)) | |
735 | var = m_acc; | |
736 | else | |
726a989a | 737 | var = adjust_return_value_with_ops (MULT_EXPR, "acc_tmp", m_acc, |
9efc83f4 | 738 | a, gsi); |
6de9cd9a DN |
739 | } |
740 | else | |
741 | var = a; | |
742 | ||
726a989a | 743 | a_acc_arg = update_accumulator_with_ops (PLUS_EXPR, a_acc, var, gsi); |
6de9cd9a DN |
744 | } |
745 | ||
746 | if (m) | |
726a989a | 747 | m_acc_arg = update_accumulator_with_ops (MULT_EXPR, m_acc, m, gsi); |
6de9cd9a DN |
748 | |
749 | if (a_acc) | |
726a989a | 750 | add_successor_phi_arg (back, a_acc, a_acc_arg); |
6de9cd9a DN |
751 | |
752 | if (m_acc) | |
726a989a | 753 | add_successor_phi_arg (back, m_acc, m_acc_arg); |
6de9cd9a DN |
754 | } |
755 | ||
1ea7e6ad | 756 | /* Adjust value of the return at the end of BB according to M and A |
6de9cd9a DN |
757 | accumulators. */ |
758 | ||
759 | static void | |
760 | adjust_return_value (basic_block bb, tree m, tree a) | |
761 | { | |
726a989a | 762 | tree retval; |
538dd0b7 | 763 | greturn *ret_stmt = as_a <greturn *> (gimple_seq_last_stmt (bb_seq (bb))); |
726a989a | 764 | gimple_stmt_iterator gsi = gsi_last_bb (bb); |
6de9cd9a | 765 | |
726a989a | 766 | gcc_assert (gimple_code (ret_stmt) == GIMPLE_RETURN); |
6de9cd9a | 767 | |
726a989a RB |
768 | retval = gimple_return_retval (ret_stmt); |
769 | if (!retval || retval == error_mark_node) | |
6de9cd9a DN |
770 | return; |
771 | ||
6de9cd9a | 772 | if (m) |
726a989a | 773 | retval = adjust_return_value_with_ops (MULT_EXPR, "mul_tmp", m_acc, retval, |
9efc83f4 | 774 | gsi); |
6de9cd9a | 775 | if (a) |
726a989a | 776 | retval = adjust_return_value_with_ops (PLUS_EXPR, "acc_tmp", a_acc, retval, |
9efc83f4 | 777 | gsi); |
726a989a | 778 | gimple_return_set_retval (ret_stmt, retval); |
f430bae8 | 779 | update_stmt (ret_stmt); |
6de9cd9a DN |
780 | } |
781 | ||
23504559 JH |
782 | /* Subtract COUNT and FREQUENCY from the basic block and it's |
783 | outgoing edge. */ | |
784 | static void | |
785 | decrease_profile (basic_block bb, gcov_type count, int frequency) | |
786 | { | |
787 | edge e; | |
788 | bb->count -= count; | |
789 | if (bb->count < 0) | |
790 | bb->count = 0; | |
791 | bb->frequency -= frequency; | |
792 | if (bb->frequency < 0) | |
793 | bb->frequency = 0; | |
794 | if (!single_succ_p (bb)) | |
795 | { | |
796 | gcc_assert (!EDGE_COUNT (bb->succs)); | |
797 | return; | |
798 | } | |
799 | e = single_succ_edge (bb); | |
800 | e->count -= count; | |
801 | if (e->count < 0) | |
802 | e->count = 0; | |
803 | } | |
804 | ||
016925bc ZD |
805 | /* Returns true if argument PARAM of the tail recursive call needs to be copied |
806 | when the call is eliminated. */ | |
807 | ||
808 | static bool | |
809 | arg_needs_copy_p (tree param) | |
810 | { | |
811 | tree def; | |
812 | ||
5f564b8f | 813 | if (!is_gimple_reg (param)) |
016925bc | 814 | return false; |
b8698a0f | 815 | |
016925bc | 816 | /* Parameters that are only defined but never used need not be copied. */ |
32244553 | 817 | def = ssa_default_def (cfun, param); |
016925bc ZD |
818 | if (!def) |
819 | return false; | |
820 | ||
821 | return true; | |
822 | } | |
823 | ||
6de9cd9a DN |
824 | /* Eliminates tail call described by T. TMP_VARS is a list of |
825 | temporary variables used to copy the function arguments. */ | |
826 | ||
827 | static void | |
828 | eliminate_tail_call (struct tailcall *t) | |
829 | { | |
726a989a RB |
830 | tree param, rslt; |
831 | gimple stmt, call; | |
5039610b | 832 | tree arg; |
726a989a | 833 | size_t idx; |
6de9cd9a DN |
834 | basic_block bb, first; |
835 | edge e; | |
538dd0b7 DM |
836 | gphi *phi; |
837 | gphi_iterator gpi; | |
726a989a RB |
838 | gimple_stmt_iterator gsi; |
839 | gimple orig_stmt; | |
6de9cd9a | 840 | |
726a989a RB |
841 | stmt = orig_stmt = gsi_stmt (t->call_gsi); |
842 | bb = gsi_bb (t->call_gsi); | |
6de9cd9a DN |
843 | |
844 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
845 | { | |
846 | fprintf (dump_file, "Eliminated tail recursion in bb %d : ", | |
847 | bb->index); | |
726a989a | 848 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
6de9cd9a DN |
849 | fprintf (dump_file, "\n"); |
850 | } | |
851 | ||
726a989a | 852 | gcc_assert (is_gimple_call (stmt)); |
6de9cd9a | 853 | |
fefa31b5 | 854 | first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
6de9cd9a | 855 | |
726a989a | 856 | /* Remove the code after call_gsi that will become unreachable. The |
8d3d51b5 ZD |
857 | possibly unreachable code in other blocks is removed later in |
858 | cfg cleanup. */ | |
726a989a RB |
859 | gsi = t->call_gsi; |
860 | gsi_next (&gsi); | |
861 | while (!gsi_end_p (gsi)) | |
8d3d51b5 | 862 | { |
726a989a | 863 | gimple t = gsi_stmt (gsi); |
8d3d51b5 ZD |
864 | /* Do not remove the return statement, so that redirect_edge_and_branch |
865 | sees how the block ends. */ | |
726a989a | 866 | if (gimple_code (t) == GIMPLE_RETURN) |
8d3d51b5 ZD |
867 | break; |
868 | ||
726a989a | 869 | gsi_remove (&gsi, true); |
87527e4b | 870 | release_defs (t); |
8d3d51b5 ZD |
871 | } |
872 | ||
23504559 | 873 | /* Number of executions of function has reduced by the tailcall. */ |
726a989a | 874 | e = single_succ_edge (gsi_bb (t->call_gsi)); |
fefa31b5 DM |
875 | decrease_profile (EXIT_BLOCK_PTR_FOR_FN (cfun), e->count, EDGE_FREQUENCY (e)); |
876 | decrease_profile (ENTRY_BLOCK_PTR_FOR_FN (cfun), e->count, | |
877 | EDGE_FREQUENCY (e)); | |
878 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
23504559 JH |
879 | decrease_profile (e->dest, e->count, EDGE_FREQUENCY (e)); |
880 | ||
6de9cd9a | 881 | /* Replace the call by a jump to the start of function. */ |
726a989a RB |
882 | e = redirect_edge_and_branch (single_succ_edge (gsi_bb (t->call_gsi)), |
883 | first); | |
1e128c5f | 884 | gcc_assert (e); |
726a989a | 885 | PENDING_STMT (e) = NULL; |
6de9cd9a | 886 | |
016925bc ZD |
887 | /* Add phi node entries for arguments. The ordering of the phi nodes should |
888 | be the same as the ordering of the arguments. */ | |
6de9cd9a | 889 | for (param = DECL_ARGUMENTS (current_function_decl), |
538dd0b7 | 890 | idx = 0, gpi = gsi_start_phis (first); |
6de9cd9a | 891 | param; |
910ad8de | 892 | param = DECL_CHAIN (param), idx++) |
6de9cd9a | 893 | { |
016925bc | 894 | if (!arg_needs_copy_p (param)) |
6de9cd9a | 895 | continue; |
726a989a RB |
896 | |
897 | arg = gimple_call_arg (stmt, idx); | |
538dd0b7 | 898 | phi = gpi.phi (); |
016925bc | 899 | gcc_assert (param == SSA_NAME_VAR (PHI_RESULT (phi))); |
6de9cd9a | 900 | |
9e227d60 | 901 | add_phi_arg (phi, arg, e, gimple_location (stmt)); |
538dd0b7 | 902 | gsi_next (&gpi); |
6de9cd9a DN |
903 | } |
904 | ||
905 | /* Update the values of accumulators. */ | |
726a989a | 906 | adjust_accumulator_values (t->call_gsi, t->mult, t->add, e); |
6de9cd9a | 907 | |
726a989a RB |
908 | call = gsi_stmt (t->call_gsi); |
909 | rslt = gimple_call_lhs (call); | |
910 | if (rslt != NULL_TREE) | |
6de9cd9a | 911 | { |
6de9cd9a DN |
912 | /* Result of the call will no longer be defined. So adjust the |
913 | SSA_NAME_DEF_STMT accordingly. */ | |
726a989a | 914 | SSA_NAME_DEF_STMT (rslt) = gimple_build_nop (); |
6de9cd9a DN |
915 | } |
916 | ||
726a989a | 917 | gsi_remove (&t->call_gsi, true); |
87527e4b | 918 | release_defs (call); |
6de9cd9a DN |
919 | } |
920 | ||
921 | /* Optimizes the tailcall described by T. If OPT_TAILCALLS is true, also | |
922 | mark the tailcalls for the sibcall optimization. */ | |
923 | ||
924 | static bool | |
925 | optimize_tail_call (struct tailcall *t, bool opt_tailcalls) | |
926 | { | |
927 | if (t->tail_recursion) | |
928 | { | |
929 | eliminate_tail_call (t); | |
930 | return true; | |
931 | } | |
932 | ||
933 | if (opt_tailcalls) | |
934 | { | |
538dd0b7 | 935 | gcall *stmt = as_a <gcall *> (gsi_stmt (t->call_gsi)); |
6de9cd9a | 936 | |
726a989a | 937 | gimple_call_set_tail (stmt, true); |
e2f0f5f7 | 938 | cfun->tail_call_marked = true; |
6de9cd9a DN |
939 | if (dump_file && (dump_flags & TDF_DETAILS)) |
940 | { | |
941 | fprintf (dump_file, "Found tail call "); | |
726a989a RB |
942 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
943 | fprintf (dump_file, " in bb %i\n", (gsi_bb (t->call_gsi))->index); | |
6de9cd9a DN |
944 | } |
945 | } | |
946 | ||
947 | return false; | |
948 | } | |
949 | ||
726a989a RB |
950 | /* Creates a tail-call accumulator of the same type as the return type of the |
951 | current function. LABEL is the name used to creating the temporary | |
952 | variable for the accumulator. The accumulator will be inserted in the | |
953 | phis of a basic block BB with single predecessor with an initial value | |
954 | INIT converted to the current function return type. */ | |
955 | ||
956 | static tree | |
957 | create_tailcall_accumulator (const char *label, basic_block bb, tree init) | |
958 | { | |
959 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl)); | |
6b00d7dd JJ |
960 | if (POINTER_TYPE_P (ret_type)) |
961 | ret_type = sizetype; | |
962 | ||
83d5977e | 963 | tree tmp = make_temp_ssa_name (ret_type, NULL, label); |
538dd0b7 | 964 | gphi *phi; |
726a989a | 965 | |
726a989a RB |
966 | phi = create_phi_node (tmp, bb); |
967 | /* RET_TYPE can be a float when -ffast-maths is enabled. */ | |
f5045c96 | 968 | add_phi_arg (phi, fold_convert (ret_type, init), single_pred_edge (bb), |
9e227d60 | 969 | UNKNOWN_LOCATION); |
726a989a RB |
970 | return PHI_RESULT (phi); |
971 | } | |
b8698a0f | 972 | |
6de9cd9a DN |
973 | /* Optimizes tail calls in the function, turning the tail recursion |
974 | into iteration. */ | |
975 | ||
1994bfea | 976 | static unsigned int |
6de9cd9a DN |
977 | tree_optimize_tail_calls_1 (bool opt_tailcalls) |
978 | { | |
979 | edge e; | |
980 | bool phis_constructed = false; | |
981 | struct tailcall *tailcalls = NULL, *act, *next; | |
982 | bool changed = false; | |
fefa31b5 | 983 | basic_block first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
726a989a RB |
984 | tree param; |
985 | gimple stmt; | |
628f6a4e | 986 | edge_iterator ei; |
6de9cd9a DN |
987 | |
988 | if (!suitable_for_tail_opt_p ()) | |
1994bfea | 989 | return 0; |
6de9cd9a DN |
990 | if (opt_tailcalls) |
991 | opt_tailcalls = suitable_for_tail_call_opt_p (); | |
992 | ||
fefa31b5 | 993 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) |
6de9cd9a DN |
994 | { |
995 | /* Only traverse the normal exits, i.e. those that end with return | |
996 | statement. */ | |
997 | stmt = last_stmt (e->src); | |
998 | ||
999 | if (stmt | |
726a989a | 1000 | && gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
1001 | find_tail_calls (e->src, &tailcalls); |
1002 | } | |
1003 | ||
1004 | /* Construct the phi nodes and accumulators if necessary. */ | |
1005 | a_acc = m_acc = NULL_TREE; | |
1006 | for (act = tailcalls; act; act = act->next) | |
1007 | { | |
1008 | if (!act->tail_recursion) | |
1009 | continue; | |
1010 | ||
1011 | if (!phis_constructed) | |
1012 | { | |
5006671f RG |
1013 | /* Ensure that there is only one predecessor of the block |
1014 | or if there are existing degenerate PHI nodes. */ | |
1015 | if (!single_pred_p (first) | |
1016 | || !gimple_seq_empty_p (phi_nodes (first))) | |
fefa31b5 DM |
1017 | first = |
1018 | split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
6de9cd9a DN |
1019 | |
1020 | /* Copy the args if needed. */ | |
1021 | for (param = DECL_ARGUMENTS (current_function_decl); | |
1022 | param; | |
910ad8de | 1023 | param = DECL_CHAIN (param)) |
016925bc ZD |
1024 | if (arg_needs_copy_p (param)) |
1025 | { | |
32244553 | 1026 | tree name = ssa_default_def (cfun, param); |
016925bc | 1027 | tree new_name = make_ssa_name (param, SSA_NAME_DEF_STMT (name)); |
538dd0b7 | 1028 | gphi *phi; |
016925bc | 1029 | |
32244553 | 1030 | set_ssa_default_def (cfun, param, new_name); |
016925bc | 1031 | phi = create_phi_node (name, first); |
b8698a0f | 1032 | add_phi_arg (phi, new_name, single_pred_edge (first), |
9e227d60 | 1033 | EXPR_LOCATION (param)); |
016925bc | 1034 | } |
6de9cd9a DN |
1035 | phis_constructed = true; |
1036 | } | |
1037 | ||
1038 | if (act->add && !a_acc) | |
726a989a RB |
1039 | a_acc = create_tailcall_accumulator ("add_acc", first, |
1040 | integer_zero_node); | |
6de9cd9a DN |
1041 | |
1042 | if (act->mult && !m_acc) | |
726a989a RB |
1043 | m_acc = create_tailcall_accumulator ("mult_acc", first, |
1044 | integer_one_node); | |
016925bc ZD |
1045 | } |
1046 | ||
1400c8e5 ZD |
1047 | if (a_acc || m_acc) |
1048 | { | |
1049 | /* When the tail call elimination using accumulators is performed, | |
1050 | statements adding the accumulated value are inserted at all exits. | |
1051 | This turns all other tail calls to non-tail ones. */ | |
1052 | opt_tailcalls = false; | |
1053 | } | |
1054 | ||
6de9cd9a DN |
1055 | for (; tailcalls; tailcalls = next) |
1056 | { | |
1057 | next = tailcalls->next; | |
1058 | changed |= optimize_tail_call (tailcalls, opt_tailcalls); | |
1059 | free (tailcalls); | |
1060 | } | |
1061 | ||
1062 | if (a_acc || m_acc) | |
1063 | { | |
1064 | /* Modify the remaining return statements. */ | |
fefa31b5 | 1065 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds) |
6de9cd9a DN |
1066 | { |
1067 | stmt = last_stmt (e->src); | |
1068 | ||
1069 | if (stmt | |
726a989a | 1070 | && gimple_code (stmt) == GIMPLE_RETURN) |
6de9cd9a DN |
1071 | adjust_return_value (e->src, m_acc, a_acc); |
1072 | } | |
1073 | } | |
1074 | ||
1075 | if (changed) | |
0d5049b2 RB |
1076 | { |
1077 | /* We may have created new loops. Make them magically appear. */ | |
726338f4 | 1078 | loops_state_set (LOOPS_NEED_FIXUP); |
0d5049b2 RB |
1079 | free_dominance_info (CDI_DOMINATORS); |
1080 | } | |
016925bc | 1081 | |
824f71b9 RG |
1082 | /* Add phi nodes for the virtual operands defined in the function to the |
1083 | header of the loop created by tail recursion elimination. Do so | |
1084 | by triggering the SSA renamer. */ | |
016925bc | 1085 | if (phis_constructed) |
525174a2 | 1086 | mark_virtual_operands_for_renaming (cfun); |
824f71b9 | 1087 | |
1994bfea JH |
1088 | if (changed) |
1089 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; | |
1090 | return 0; | |
6de9cd9a DN |
1091 | } |
1092 | ||
6de9cd9a DN |
1093 | static bool |
1094 | gate_tail_calls (void) | |
1095 | { | |
6fb5fa3c | 1096 | return flag_optimize_sibling_calls != 0 && dbg_cnt (tail_call); |
6de9cd9a DN |
1097 | } |
1098 | ||
c2924966 | 1099 | static unsigned int |
6de9cd9a DN |
1100 | execute_tail_calls (void) |
1101 | { | |
1994bfea | 1102 | return tree_optimize_tail_calls_1 (true); |
6de9cd9a DN |
1103 | } |
1104 | ||
27a4cd48 DM |
1105 | namespace { |
1106 | ||
1107 | const pass_data pass_data_tail_recursion = | |
6de9cd9a | 1108 | { |
27a4cd48 DM |
1109 | GIMPLE_PASS, /* type */ |
1110 | "tailr", /* name */ | |
1111 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
1112 | TV_NONE, /* tv_id */ |
1113 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1114 | 0, /* properties_provided */ | |
1115 | 0, /* properties_destroyed */ | |
1116 | 0, /* todo_flags_start */ | |
3bea341f | 1117 | 0, /* todo_flags_finish */ |
6de9cd9a DN |
1118 | }; |
1119 | ||
27a4cd48 DM |
1120 | class pass_tail_recursion : public gimple_opt_pass |
1121 | { | |
1122 | public: | |
c3284718 RS |
1123 | pass_tail_recursion (gcc::context *ctxt) |
1124 | : gimple_opt_pass (pass_data_tail_recursion, ctxt) | |
27a4cd48 DM |
1125 | {} |
1126 | ||
1127 | /* opt_pass methods: */ | |
65d3284b | 1128 | opt_pass * clone () { return new pass_tail_recursion (m_ctxt); } |
1a3d085c | 1129 | virtual bool gate (function *) { return gate_tail_calls (); } |
be55bfe6 TS |
1130 | virtual unsigned int execute (function *) |
1131 | { | |
1132 | return tree_optimize_tail_calls_1 (false); | |
1133 | } | |
27a4cd48 DM |
1134 | |
1135 | }; // class pass_tail_recursion | |
1136 | ||
1137 | } // anon namespace | |
1138 | ||
1139 | gimple_opt_pass * | |
1140 | make_pass_tail_recursion (gcc::context *ctxt) | |
1141 | { | |
1142 | return new pass_tail_recursion (ctxt); | |
1143 | } | |
1144 | ||
1145 | namespace { | |
1146 | ||
1147 | const pass_data pass_data_tail_calls = | |
6de9cd9a | 1148 | { |
27a4cd48 DM |
1149 | GIMPLE_PASS, /* type */ |
1150 | "tailc", /* name */ | |
1151 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
1152 | TV_NONE, /* tv_id */ |
1153 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1154 | 0, /* properties_provided */ | |
1155 | 0, /* properties_destroyed */ | |
1156 | 0, /* todo_flags_start */ | |
3bea341f | 1157 | 0, /* todo_flags_finish */ |
6de9cd9a | 1158 | }; |
27a4cd48 DM |
1159 | |
1160 | class pass_tail_calls : public gimple_opt_pass | |
1161 | { | |
1162 | public: | |
c3284718 RS |
1163 | pass_tail_calls (gcc::context *ctxt) |
1164 | : gimple_opt_pass (pass_data_tail_calls, ctxt) | |
27a4cd48 DM |
1165 | {} |
1166 | ||
1167 | /* opt_pass methods: */ | |
1a3d085c | 1168 | virtual bool gate (function *) { return gate_tail_calls (); } |
be55bfe6 | 1169 | virtual unsigned int execute (function *) { return execute_tail_calls (); } |
27a4cd48 DM |
1170 | |
1171 | }; // class pass_tail_calls | |
1172 | ||
1173 | } // anon namespace | |
1174 | ||
1175 | gimple_opt_pass * | |
1176 | make_pass_tail_calls (gcc::context *ctxt) | |
1177 | { | |
1178 | return new pass_tail_calls (ctxt); | |
1179 | } |