Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-ifcombine.c @ 132:d34655255c78
update gcc-8.2
author | mir3636 |
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date | Thu, 25 Oct 2018 10:21:07 +0900 |
parents | 84e7813d76e9 |
children | 1830386684a0 |
rev | line source |
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0 | 1 /* Combining of if-expressions on trees. |
131 | 2 Copyright (C) 2007-2018 Free Software Foundation, Inc. |
0 | 3 Contributed by Richard Guenther <rguenther@suse.de> |
4 | |
5 This file is part of GCC. | |
6 | |
7 GCC is free software; you can redistribute it and/or modify | |
8 it under the terms of the GNU General Public License as published by | |
9 the Free Software Foundation; either version 3, or (at your option) | |
10 any later version. | |
11 | |
12 GCC is distributed in the hope that it will be useful, | |
13 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 GNU General Public License for more details. | |
16 | |
17 You should have received a copy of the GNU General Public License | |
18 along with GCC; see the file COPYING3. If not see | |
19 <http://www.gnu.org/licenses/>. */ | |
20 | |
21 #include "config.h" | |
22 #include "system.h" | |
23 #include "coretypes.h" | |
111 | 24 #include "backend.h" |
25 #include "rtl.h" | |
0 | 26 #include "tree.h" |
111 | 27 #include "gimple.h" |
28 #include "cfghooks.h" | |
29 #include "tree-pass.h" | |
30 #include "memmodel.h" | |
31 #include "tm_p.h" | |
32 #include "ssa.h" | |
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33 #include "tree-pretty-print.h" |
111 | 34 /* rtl is needed only because arm back-end requires it for |
35 BRANCH_COST. */ | |
36 #include "fold-const.h" | |
37 #include "cfganal.h" | |
38 #include "gimple-fold.h" | |
39 #include "gimple-iterator.h" | |
40 #include "gimplify-me.h" | |
41 #include "tree-cfg.h" | |
42 #include "tree-ssa.h" | |
43 | |
44 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT | |
45 #define LOGICAL_OP_NON_SHORT_CIRCUIT \ | |
46 (BRANCH_COST (optimize_function_for_speed_p (cfun), \ | |
47 false) >= 2) | |
48 #endif | |
0 | 49 |
50 /* This pass combines COND_EXPRs to simplify control flow. It | |
51 currently recognizes bit tests and comparisons in chains that | |
52 represent logical and or logical or of two COND_EXPRs. | |
53 | |
54 It does so by walking basic blocks in a approximate reverse | |
55 post-dominator order and trying to match CFG patterns that | |
56 represent logical and or logical or of two COND_EXPRs. | |
57 Transformations are done if the COND_EXPR conditions match | |
58 either | |
59 | |
60 1. two single bit tests X & (1 << Yn) (for logical and) | |
61 | |
62 2. two bit tests X & Yn (for logical or) | |
63 | |
64 3. two comparisons X OPn Y (for logical or) | |
65 | |
66 To simplify this pass, removing basic blocks and dead code | |
67 is left to CFG cleanup and DCE. */ | |
68 | |
69 | |
70 /* Recognize a if-then-else CFG pattern starting to match with the | |
71 COND_BB basic-block containing the COND_EXPR. The recognized | |
72 then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
73 *THEN_BB and/or *ELSE_BB are already set, they are required to | |
74 match the then and else basic-blocks to make the pattern match. | |
75 Returns true if the pattern matched, false otherwise. */ | |
76 | |
77 static bool | |
78 recognize_if_then_else (basic_block cond_bb, | |
79 basic_block *then_bb, basic_block *else_bb) | |
80 { | |
81 edge t, e; | |
82 | |
83 if (EDGE_COUNT (cond_bb->succs) != 2) | |
84 return false; | |
85 | |
86 /* Find the then/else edges. */ | |
87 t = EDGE_SUCC (cond_bb, 0); | |
88 e = EDGE_SUCC (cond_bb, 1); | |
89 if (!(t->flags & EDGE_TRUE_VALUE)) | |
111 | 90 std::swap (t, e); |
0 | 91 if (!(t->flags & EDGE_TRUE_VALUE) |
92 || !(e->flags & EDGE_FALSE_VALUE)) | |
93 return false; | |
94 | |
95 /* Check if the edge destinations point to the required block. */ | |
96 if (*then_bb | |
97 && t->dest != *then_bb) | |
98 return false; | |
99 if (*else_bb | |
100 && e->dest != *else_bb) | |
101 return false; | |
102 | |
103 if (!*then_bb) | |
104 *then_bb = t->dest; | |
105 if (!*else_bb) | |
106 *else_bb = e->dest; | |
107 | |
108 return true; | |
109 } | |
110 | |
111 /* Verify if the basic block BB does not have side-effects. Return | |
112 true in this case, else false. */ | |
113 | |
114 static bool | |
115 bb_no_side_effects_p (basic_block bb) | |
116 { | |
117 gimple_stmt_iterator gsi; | |
118 | |
119 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
120 { | |
111 | 121 gimple *stmt = gsi_stmt (gsi); |
122 | |
123 if (is_gimple_debug (stmt)) | |
124 continue; | |
0 | 125 |
111 | 126 if (gimple_has_side_effects (stmt) |
127 || gimple_uses_undefined_value_p (stmt) | |
128 || gimple_could_trap_p (stmt) | |
129 || gimple_vuse (stmt) | |
130 /* const calls don't match any of the above, yet they could | |
131 still have some side-effects - they could contain | |
132 gimple_could_trap_p statements, like floating point | |
133 exceptions or integer division by zero. See PR70586. | |
134 FIXME: perhaps gimple_has_side_effects or gimple_could_trap_p | |
135 should handle this. */ | |
136 || is_gimple_call (stmt)) | |
0 | 137 return false; |
138 } | |
139 | |
140 return true; | |
141 } | |
142 | |
111 | 143 /* Return true if BB is an empty forwarder block to TO_BB. */ |
144 | |
145 static bool | |
146 forwarder_block_to (basic_block bb, basic_block to_bb) | |
147 { | |
148 return empty_block_p (bb) | |
149 && single_succ_p (bb) | |
150 && single_succ (bb) == to_bb; | |
151 } | |
152 | |
0 | 153 /* Verify if all PHI node arguments in DEST for edges from BB1 or |
154 BB2 to DEST are the same. This makes the CFG merge point | |
155 free from side-effects. Return true in this case, else false. */ | |
156 | |
157 static bool | |
158 same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
159 { | |
160 edge e1 = find_edge (bb1, dest); | |
161 edge e2 = find_edge (bb2, dest); | |
111 | 162 gphi_iterator gsi; |
163 gphi *phi; | |
0 | 164 |
165 for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
166 { | |
111 | 167 phi = gsi.phi (); |
0 | 168 if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), |
169 PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
170 return false; | |
171 } | |
172 | |
173 return true; | |
174 } | |
175 | |
176 /* Return the best representative SSA name for CANDIDATE which is used | |
177 in a bit test. */ | |
178 | |
179 static tree | |
180 get_name_for_bit_test (tree candidate) | |
181 { | |
182 /* Skip single-use names in favor of using the name from a | |
183 non-widening conversion definition. */ | |
184 if (TREE_CODE (candidate) == SSA_NAME | |
185 && has_single_use (candidate)) | |
186 { | |
111 | 187 gimple *def_stmt = SSA_NAME_DEF_STMT (candidate); |
0 | 188 if (is_gimple_assign (def_stmt) |
36 | 189 && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
0 | 190 { |
191 if (TYPE_PRECISION (TREE_TYPE (candidate)) | |
192 <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
193 return gimple_assign_rhs1 (def_stmt); | |
194 } | |
195 } | |
196 | |
197 return candidate; | |
198 } | |
199 | |
200 /* Recognize a single bit test pattern in GIMPLE_COND and its defining | |
201 statements. Store the name being tested in *NAME and the bit | |
202 in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). | |
203 Returns true if the pattern matched, false otherwise. */ | |
204 | |
205 static bool | |
111 | 206 recognize_single_bit_test (gcond *cond, tree *name, tree *bit, bool inv) |
0 | 207 { |
111 | 208 gimple *stmt; |
0 | 209 |
210 /* Get at the definition of the result of the bit test. */ | |
111 | 211 if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
0 | 212 || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
213 || !integer_zerop (gimple_cond_rhs (cond))) | |
214 return false; | |
215 stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); | |
216 if (!is_gimple_assign (stmt)) | |
217 return false; | |
218 | |
219 /* Look at which bit is tested. One form to recognize is | |
220 D.1985_5 = state_3(D) >> control1_4(D); | |
221 D.1986_6 = (int) D.1985_5; | |
222 D.1987_7 = op0 & 1; | |
223 if (D.1987_7 != 0) */ | |
224 if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR | |
225 && integer_onep (gimple_assign_rhs2 (stmt)) | |
226 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
227 { | |
228 tree orig_name = gimple_assign_rhs1 (stmt); | |
229 | |
230 /* Look through copies and conversions to eventually | |
231 find the stmt that computes the shift. */ | |
232 stmt = SSA_NAME_DEF_STMT (orig_name); | |
233 | |
234 while (is_gimple_assign (stmt) | |
36 | 235 && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
236 && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
111 | 237 <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))) |
238 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
36 | 239 || gimple_assign_ssa_name_copy_p (stmt))) |
240 stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
0 | 241 |
242 /* If we found such, decompose it. */ | |
243 if (is_gimple_assign (stmt) | |
244 && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
245 { | |
246 /* op0 & (1 << op1) */ | |
247 *bit = gimple_assign_rhs2 (stmt); | |
248 *name = gimple_assign_rhs1 (stmt); | |
249 } | |
250 else | |
251 { | |
252 /* t & 1 */ | |
253 *bit = integer_zero_node; | |
254 *name = get_name_for_bit_test (orig_name); | |
255 } | |
256 | |
257 return true; | |
258 } | |
259 | |
260 /* Another form is | |
261 D.1987_7 = op0 & (1 << CST) | |
262 if (D.1987_7 != 0) */ | |
263 if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR | |
264 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
265 && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
266 { | |
267 *name = gimple_assign_rhs1 (stmt); | |
268 *bit = build_int_cst (integer_type_node, | |
269 tree_log2 (gimple_assign_rhs2 (stmt))); | |
270 return true; | |
271 } | |
272 | |
273 /* Another form is | |
274 D.1986_6 = 1 << control1_4(D) | |
275 D.1987_7 = op0 & D.1986_6 | |
276 if (D.1987_7 != 0) */ | |
277 if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR | |
278 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
279 && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
280 { | |
111 | 281 gimple *tmp; |
0 | 282 |
283 /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
284 specifying expression. */ | |
285 tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
286 if (is_gimple_assign (tmp) | |
287 && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
288 && integer_onep (gimple_assign_rhs1 (tmp))) | |
289 { | |
290 *name = gimple_assign_rhs2 (stmt); | |
291 *bit = gimple_assign_rhs2 (tmp); | |
292 return true; | |
293 } | |
294 | |
295 tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); | |
296 if (is_gimple_assign (tmp) | |
297 && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
298 && integer_onep (gimple_assign_rhs1 (tmp))) | |
299 { | |
300 *name = gimple_assign_rhs1 (stmt); | |
301 *bit = gimple_assign_rhs2 (tmp); | |
302 return true; | |
303 } | |
304 } | |
305 | |
306 return false; | |
307 } | |
308 | |
309 /* Recognize a bit test pattern in a GIMPLE_COND and its defining | |
310 statements. Store the name being tested in *NAME and the bits | |
311 in *BITS. The COND_EXPR computes *NAME & *BITS. | |
312 Returns true if the pattern matched, false otherwise. */ | |
313 | |
314 static bool | |
111 | 315 recognize_bits_test (gcond *cond, tree *name, tree *bits, bool inv) |
0 | 316 { |
111 | 317 gimple *stmt; |
0 | 318 |
319 /* Get at the definition of the result of the bit test. */ | |
111 | 320 if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
0 | 321 || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
322 || !integer_zerop (gimple_cond_rhs (cond))) | |
323 return false; | |
324 stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); | |
325 if (!is_gimple_assign (stmt) | |
326 || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
327 return false; | |
328 | |
329 *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); | |
330 *bits = gimple_assign_rhs2 (stmt); | |
331 | |
332 return true; | |
333 } | |
334 | |
111 | 335 |
336 /* Update profile after code in outer_cond_bb was adjusted so | |
337 outer_cond_bb has no condition. */ | |
338 | |
339 static void | |
340 update_profile_after_ifcombine (basic_block inner_cond_bb, | |
341 basic_block outer_cond_bb) | |
342 { | |
343 edge outer_to_inner = find_edge (outer_cond_bb, inner_cond_bb); | |
344 edge outer2 = (EDGE_SUCC (outer_cond_bb, 0) == outer_to_inner | |
345 ? EDGE_SUCC (outer_cond_bb, 1) | |
346 : EDGE_SUCC (outer_cond_bb, 0)); | |
347 edge inner_taken = EDGE_SUCC (inner_cond_bb, 0); | |
348 edge inner_not_taken = EDGE_SUCC (inner_cond_bb, 1); | |
349 | |
350 if (inner_taken->dest != outer2->dest) | |
351 std::swap (inner_taken, inner_not_taken); | |
352 gcc_assert (inner_taken->dest == outer2->dest); | |
353 | |
354 /* In the following we assume that inner_cond_bb has single predecessor. */ | |
355 gcc_assert (single_pred_p (inner_cond_bb)); | |
356 | |
357 /* Path outer_cond_bb->(outer2) needs to be merged into path | |
358 outer_cond_bb->(outer_to_inner)->inner_cond_bb->(inner_taken) | |
359 and probability of inner_not_taken updated. */ | |
360 | |
361 inner_cond_bb->count = outer_cond_bb->count; | |
362 | |
363 inner_taken->probability = outer2->probability + outer_to_inner->probability | |
364 * inner_taken->probability; | |
365 inner_not_taken->probability = profile_probability::always () | |
366 - inner_taken->probability; | |
367 | |
368 outer_to_inner->probability = profile_probability::always (); | |
369 outer2->probability = profile_probability::never (); | |
370 } | |
371 | |
0 | 372 /* If-convert on a and pattern with a common else block. The inner |
373 if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
111 | 374 inner_inv, outer_inv and result_inv indicate whether the conditions |
375 are inverted. | |
0 | 376 Returns true if the edges to the common else basic-block were merged. */ |
377 | |
378 static bool | |
111 | 379 ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
380 basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
0 | 381 { |
382 gimple_stmt_iterator gsi; | |
111 | 383 gimple *inner_stmt, *outer_stmt; |
384 gcond *inner_cond, *outer_cond; | |
385 tree name1, name2, bit1, bit2, bits1, bits2; | |
0 | 386 |
111 | 387 inner_stmt = last_stmt (inner_cond_bb); |
388 if (!inner_stmt | |
389 || gimple_code (inner_stmt) != GIMPLE_COND) | |
0 | 390 return false; |
111 | 391 inner_cond = as_a <gcond *> (inner_stmt); |
0 | 392 |
111 | 393 outer_stmt = last_stmt (outer_cond_bb); |
394 if (!outer_stmt | |
395 || gimple_code (outer_stmt) != GIMPLE_COND) | |
0 | 396 return false; |
111 | 397 outer_cond = as_a <gcond *> (outer_stmt); |
0 | 398 |
399 /* See if we test a single bit of the same name in both tests. In | |
400 that case remove the outer test, merging both else edges, | |
401 and change the inner one to test for | |
402 name & (bit1 | bit2) == (bit1 | bit2). */ | |
111 | 403 if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
404 && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
0 | 405 && name1 == name2) |
406 { | |
407 tree t, t2; | |
408 | |
409 /* Do it. */ | |
410 gsi = gsi_for_stmt (inner_cond); | |
411 t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), | |
412 build_int_cst (TREE_TYPE (name1), 1), bit1); | |
413 t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), | |
414 build_int_cst (TREE_TYPE (name1), 1), bit2); | |
415 t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); | |
416 t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, | |
417 true, GSI_SAME_STMT); | |
418 t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); | |
419 t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, | |
420 true, GSI_SAME_STMT); | |
111 | 421 t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
422 boolean_type_node, t2, t); | |
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423 t = canonicalize_cond_expr_cond (t); |
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424 if (!t) |
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425 return false; |
0 | 426 gimple_cond_set_condition_from_tree (inner_cond, t); |
427 update_stmt (inner_cond); | |
428 | |
429 /* Leave CFG optimization to cfg_cleanup. */ | |
111 | 430 gimple_cond_set_condition_from_tree (outer_cond, |
431 outer_inv ? boolean_false_node : boolean_true_node); | |
0 | 432 update_stmt (outer_cond); |
433 | |
111 | 434 update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
435 | |
0 | 436 if (dump_file) |
437 { | |
438 fprintf (dump_file, "optimizing double bit test to "); | |
111 | 439 print_generic_expr (dump_file, name1); |
0 | 440 fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); |
111 | 441 print_generic_expr (dump_file, bit1); |
0 | 442 fprintf (dump_file, ") | (1 << "); |
111 | 443 print_generic_expr (dump_file, bit2); |
0 | 444 fprintf (dump_file, ")\n"); |
445 } | |
446 | |
447 return true; | |
448 } | |
449 | |
450 /* See if we have two bit tests of the same name in both tests. | |
451 In that case remove the outer test and change the inner one to | |
452 test for name & (bits1 | bits2) != 0. */ | |
111 | 453 else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
454 && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
0 | 455 { |
456 gimple_stmt_iterator gsi; | |
457 tree t; | |
458 | |
459 /* Find the common name which is bit-tested. */ | |
460 if (name1 == name2) | |
461 ; | |
462 else if (bits1 == bits2) | |
463 { | |
111 | 464 std::swap (name2, bits2); |
465 std::swap (name1, bits1); | |
0 | 466 } |
467 else if (name1 == bits2) | |
111 | 468 std::swap (name2, bits2); |
0 | 469 else if (bits1 == name2) |
111 | 470 std::swap (name1, bits1); |
0 | 471 else |
472 return false; | |
473 | |
474 /* As we strip non-widening conversions in finding a common | |
475 name that is tested make sure to end up with an integral | |
476 type for building the bit operations. */ | |
477 if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
478 >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
479 { | |
480 bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
481 name1 = fold_convert (TREE_TYPE (bits1), name1); | |
482 bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
483 bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
484 } | |
485 else | |
486 { | |
487 bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
488 name1 = fold_convert (TREE_TYPE (bits2), name1); | |
489 bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
490 bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
491 } | |
492 | |
493 /* Do it. */ | |
494 gsi = gsi_for_stmt (inner_cond); | |
495 t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); | |
496 t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, | |
497 true, GSI_SAME_STMT); | |
498 t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); | |
499 t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, | |
500 true, GSI_SAME_STMT); | |
111 | 501 t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
0 | 502 build_int_cst (TREE_TYPE (t), 0)); |
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503 t = canonicalize_cond_expr_cond (t); |
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504 if (!t) |
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diff
changeset
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505 return false; |
0 | 506 gimple_cond_set_condition_from_tree (inner_cond, t); |
507 update_stmt (inner_cond); | |
508 | |
509 /* Leave CFG optimization to cfg_cleanup. */ | |
111 | 510 gimple_cond_set_condition_from_tree (outer_cond, |
511 outer_inv ? boolean_false_node : boolean_true_node); | |
0 | 512 update_stmt (outer_cond); |
111 | 513 update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
0 | 514 |
515 if (dump_file) | |
516 { | |
517 fprintf (dump_file, "optimizing bits or bits test to "); | |
111 | 518 print_generic_expr (dump_file, name1); |
0 | 519 fprintf (dump_file, " & T != 0\nwith temporary T = "); |
111 | 520 print_generic_expr (dump_file, bits1); |
0 | 521 fprintf (dump_file, " | "); |
111 | 522 print_generic_expr (dump_file, bits2); |
0 | 523 fprintf (dump_file, "\n"); |
524 } | |
525 | |
526 return true; | |
527 } | |
528 | |
111 | 529 /* See if we have two comparisons that we can merge into one. */ |
530 else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
531 && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
0 | 532 { |
533 tree t; | |
111 | 534 enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
535 enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
0 | 536 |
111 | 537 /* Invert comparisons if necessary (and possible). */ |
538 if (inner_inv) | |
539 inner_cond_code = invert_tree_comparison (inner_cond_code, | |
540 HONOR_NANS (gimple_cond_lhs (inner_cond))); | |
541 if (inner_cond_code == ERROR_MARK) | |
542 return false; | |
543 if (outer_inv) | |
544 outer_cond_code = invert_tree_comparison (outer_cond_code, | |
545 HONOR_NANS (gimple_cond_lhs (outer_cond))); | |
546 if (outer_cond_code == ERROR_MARK) | |
0 | 547 return false; |
111 | 548 /* Don't return false so fast, try maybe_fold_or_comparisons? */ |
549 | |
550 if (!(t = maybe_fold_and_comparisons (inner_cond_code, | |
551 gimple_cond_lhs (inner_cond), | |
552 gimple_cond_rhs (inner_cond), | |
553 outer_cond_code, | |
554 gimple_cond_lhs (outer_cond), | |
555 gimple_cond_rhs (outer_cond)))) | |
556 { | |
557 tree t1, t2; | |
558 gimple_stmt_iterator gsi; | |
559 if (!LOGICAL_OP_NON_SHORT_CIRCUIT || flag_sanitize_coverage) | |
560 return false; | |
561 /* Only do this optimization if the inner bb contains only the conditional. */ | |
562 if (!gsi_one_before_end_p (gsi_start_nondebug_after_labels_bb (inner_cond_bb))) | |
563 return false; | |
564 t1 = fold_build2_loc (gimple_location (inner_cond), | |
565 inner_cond_code, | |
566 boolean_type_node, | |
567 gimple_cond_lhs (inner_cond), | |
568 gimple_cond_rhs (inner_cond)); | |
569 t2 = fold_build2_loc (gimple_location (outer_cond), | |
570 outer_cond_code, | |
571 boolean_type_node, | |
572 gimple_cond_lhs (outer_cond), | |
573 gimple_cond_rhs (outer_cond)); | |
574 t = fold_build2_loc (gimple_location (inner_cond), | |
575 TRUTH_AND_EXPR, boolean_type_node, t1, t2); | |
576 if (result_inv) | |
577 { | |
578 t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
579 result_inv = false; | |
580 } | |
581 gsi = gsi_for_stmt (inner_cond); | |
582 t = force_gimple_operand_gsi_1 (&gsi, t, is_gimple_condexpr, NULL, true, | |
583 GSI_SAME_STMT); | |
584 } | |
585 if (result_inv) | |
586 t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
0 | 587 t = canonicalize_cond_expr_cond (t); |
588 if (!t) | |
589 return false; | |
590 gimple_cond_set_condition_from_tree (inner_cond, t); | |
591 update_stmt (inner_cond); | |
592 | |
593 /* Leave CFG optimization to cfg_cleanup. */ | |
111 | 594 gimple_cond_set_condition_from_tree (outer_cond, |
595 outer_inv ? boolean_false_node : boolean_true_node); | |
0 | 596 update_stmt (outer_cond); |
111 | 597 update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
0 | 598 |
599 if (dump_file) | |
600 { | |
601 fprintf (dump_file, "optimizing two comparisons to "); | |
111 | 602 print_generic_expr (dump_file, t); |
0 | 603 fprintf (dump_file, "\n"); |
604 } | |
605 | |
606 return true; | |
607 } | |
608 | |
609 return false; | |
610 } | |
611 | |
111 | 612 /* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and |
613 dispatch to the appropriate if-conversion helper for a particular | |
614 set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. | |
615 PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ | |
616 | |
617 static bool | |
618 tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, | |
619 basic_block then_bb, basic_block else_bb, | |
620 basic_block phi_pred_bb) | |
621 { | |
622 /* The && form is characterized by a common else_bb with | |
623 the two edges leading to it mergable. The latter is | |
624 guaranteed by matching PHI arguments in the else_bb and | |
625 the inner cond_bb having no side-effects. */ | |
626 if (phi_pred_bb != else_bb | |
627 && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
628 && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) | |
629 { | |
630 /* We have | |
631 <outer_cond_bb> | |
632 if (q) goto inner_cond_bb; else goto else_bb; | |
633 <inner_cond_bb> | |
634 if (p) goto ...; else goto else_bb; | |
635 ... | |
636 <else_bb> | |
637 ... | |
638 */ | |
639 return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, | |
640 false); | |
641 } | |
642 | |
643 /* And a version where the outer condition is negated. */ | |
644 if (phi_pred_bb != else_bb | |
645 && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
646 && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) | |
647 { | |
648 /* We have | |
649 <outer_cond_bb> | |
650 if (q) goto else_bb; else goto inner_cond_bb; | |
651 <inner_cond_bb> | |
652 if (p) goto ...; else goto else_bb; | |
653 ... | |
654 <else_bb> | |
655 ... | |
656 */ | |
657 return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
658 false); | |
659 } | |
660 | |
661 /* The || form is characterized by a common then_bb with the | |
662 two edges leading to it mergable. The latter is guaranteed | |
663 by matching PHI arguments in the then_bb and the inner cond_bb | |
664 having no side-effects. */ | |
665 if (phi_pred_bb != then_bb | |
666 && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
667 && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) | |
668 { | |
669 /* We have | |
670 <outer_cond_bb> | |
671 if (q) goto then_bb; else goto inner_cond_bb; | |
672 <inner_cond_bb> | |
673 if (q) goto then_bb; else goto ...; | |
674 <then_bb> | |
675 ... | |
676 */ | |
677 return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, | |
678 true); | |
679 } | |
680 | |
681 /* And a version where the outer condition is negated. */ | |
682 if (phi_pred_bb != then_bb | |
683 && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
684 && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) | |
685 { | |
686 /* We have | |
687 <outer_cond_bb> | |
688 if (q) goto inner_cond_bb; else goto then_bb; | |
689 <inner_cond_bb> | |
690 if (q) goto then_bb; else goto ...; | |
691 <then_bb> | |
692 ... | |
693 */ | |
694 return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
695 true); | |
696 } | |
697 | |
698 return false; | |
699 } | |
700 | |
0 | 701 /* Recognize a CFG pattern and dispatch to the appropriate |
702 if-conversion helper. We start with BB as the innermost | |
703 worker basic-block. Returns true if a transformation was done. */ | |
704 | |
705 static bool | |
706 tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
707 { | |
708 basic_block then_bb = NULL, else_bb = NULL; | |
709 | |
710 if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
711 return false; | |
712 | |
713 /* Recognize && and || of two conditions with a common | |
714 then/else block which entry edges we can merge. That is: | |
715 if (a || b) | |
716 ; | |
717 and | |
718 if (a && b) | |
719 ; | |
720 This requires a single predecessor of the inner cond_bb. */ | |
111 | 721 if (single_pred_p (inner_cond_bb) |
722 && bb_no_side_effects_p (inner_cond_bb)) | |
0 | 723 { |
724 basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
725 | |
111 | 726 if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, |
727 then_bb, else_bb, inner_cond_bb)) | |
728 return true; | |
729 | |
730 if (forwarder_block_to (else_bb, then_bb)) | |
0 | 731 { |
111 | 732 /* Other possibilities for the && form, if else_bb is |
733 empty forwarder block to then_bb. Compared to the above simpler | |
734 forms this can be treated as if then_bb and else_bb were swapped, | |
735 and the corresponding inner_cond_bb not inverted because of that. | |
736 For same_phi_args_p we look at equality of arguments between | |
737 edge from outer_cond_bb and the forwarder block. */ | |
738 if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
739 then_bb, else_bb)) | |
740 return true; | |
0 | 741 } |
111 | 742 else if (forwarder_block_to (then_bb, else_bb)) |
0 | 743 { |
111 | 744 /* Other possibilities for the || form, if then_bb is |
745 empty forwarder block to else_bb. Compared to the above simpler | |
746 forms this can be treated as if then_bb and else_bb were swapped, | |
747 and the corresponding inner_cond_bb not inverted because of that. | |
748 For same_phi_args_p we look at equality of arguments between | |
749 edge from outer_cond_bb and the forwarder block. */ | |
750 if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
751 then_bb, then_bb)) | |
752 return true; | |
0 | 753 } |
754 } | |
755 | |
756 return false; | |
757 } | |
758 | |
759 /* Main entry for the tree if-conversion pass. */ | |
760 | |
111 | 761 namespace { |
762 | |
763 const pass_data pass_data_tree_ifcombine = | |
764 { | |
765 GIMPLE_PASS, /* type */ | |
766 "ifcombine", /* name */ | |
767 OPTGROUP_NONE, /* optinfo_flags */ | |
768 TV_TREE_IFCOMBINE, /* tv_id */ | |
769 ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
770 0, /* properties_provided */ | |
771 0, /* properties_destroyed */ | |
772 0, /* todo_flags_start */ | |
773 TODO_update_ssa, /* todo_flags_finish */ | |
774 }; | |
775 | |
776 class pass_tree_ifcombine : public gimple_opt_pass | |
777 { | |
778 public: | |
779 pass_tree_ifcombine (gcc::context *ctxt) | |
780 : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
781 {} | |
782 | |
783 /* opt_pass methods: */ | |
784 virtual unsigned int execute (function *); | |
785 | |
786 }; // class pass_tree_ifcombine | |
787 | |
788 unsigned int | |
789 pass_tree_ifcombine::execute (function *fun) | |
0 | 790 { |
791 basic_block *bbs; | |
792 bool cfg_changed = false; | |
793 int i; | |
794 | |
111 | 795 bbs = single_pred_before_succ_order (); |
796 calculate_dominance_info (CDI_DOMINATORS); | |
797 | |
798 /* Search every basic block for COND_EXPR we may be able to optimize. | |
0 | 799 |
111 | 800 We walk the blocks in order that guarantees that a block with |
801 a single predecessor is processed after the predecessor. | |
802 This ensures that we collapse outter ifs before visiting the | |
803 inner ones, and also that we do not try to visit a removed | |
804 block. This is opposite of PHI-OPT, because we cascade the | |
805 combining rather than cascading PHIs. */ | |
806 for (i = n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) | |
0 | 807 { |
808 basic_block bb = bbs[i]; | |
111 | 809 gimple *stmt = last_stmt (bb); |
0 | 810 |
811 if (stmt | |
812 && gimple_code (stmt) == GIMPLE_COND) | |
111 | 813 if (tree_ssa_ifcombine_bb (bb)) |
814 { | |
815 /* Clear range info from all stmts in BB which is now executed | |
816 conditional on a always true/false condition. */ | |
817 reset_flow_sensitive_info_in_bb (bb); | |
818 cfg_changed |= true; | |
819 } | |
0 | 820 } |
821 | |
822 free (bbs); | |
823 | |
824 return cfg_changed ? TODO_cleanup_cfg : 0; | |
825 } | |
826 | |
111 | 827 } // anon namespace |
0 | 828 |
111 | 829 gimple_opt_pass * |
830 make_pass_tree_ifcombine (gcc::context *ctxt) | |
0 | 831 { |
111 | 832 return new pass_tree_ifcombine (ctxt); |
833 } |