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8530c7be | 1 | /* Combining of if-expressions on trees. |
fbd26352 | 2 | Copyright (C) 2007-2019 Free Software Foundation, Inc. |
8530c7be | 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 | |
8c4c00c1 | 9 | the Free Software Foundation; either version 3, or (at your option) |
8530c7be | 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 | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
8530c7be | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
9ef16211 | 24 | #include "backend.h" |
7c29e30e | 25 | #include "rtl.h" |
9ef16211 | 26 | #include "tree.h" |
27 | #include "gimple.h" | |
7c29e30e | 28 | #include "cfghooks.h" |
29 | #include "tree-pass.h" | |
ad7b10a2 | 30 | #include "memmodel.h" |
7c29e30e | 31 | #include "tm_p.h" |
9ef16211 | 32 | #include "ssa.h" |
7c29e30e | 33 | #include "tree-pretty-print.h" |
b4c65f30 | 34 | /* rtl is needed only because arm back-end requires it for |
35 | BRANCH_COST. */ | |
b20a8bb4 | 36 | #include "fold-const.h" |
94ea8568 | 37 | #include "cfganal.h" |
bc61cadb | 38 | #include "gimple-fold.h" |
dcf1a1ec | 39 | #include "gimple-iterator.h" |
e795d6e1 | 40 | #include "gimplify-me.h" |
073c1fd5 | 41 | #include "tree-cfg.h" |
4883b250 | 42 | #include "tree-ssa.h" |
8aa5cb12 | 43 | #include "params.h" |
8530c7be | 44 | |
b4c65f30 | 45 | #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT |
46 | #define LOGICAL_OP_NON_SHORT_CIRCUIT \ | |
47 | (BRANCH_COST (optimize_function_for_speed_p (cfun), \ | |
48 | false) >= 2) | |
49 | #endif | |
50 | ||
8530c7be | 51 | /* This pass combines COND_EXPRs to simplify control flow. It |
52 | currently recognizes bit tests and comparisons in chains that | |
53 | represent logical and or logical or of two COND_EXPRs. | |
54 | ||
55 | It does so by walking basic blocks in a approximate reverse | |
56 | post-dominator order and trying to match CFG patterns that | |
57 | represent logical and or logical or of two COND_EXPRs. | |
58 | Transformations are done if the COND_EXPR conditions match | |
59 | either | |
60 | ||
61 | 1. two single bit tests X & (1 << Yn) (for logical and) | |
62 | ||
63 | 2. two bit tests X & Yn (for logical or) | |
64 | ||
65 | 3. two comparisons X OPn Y (for logical or) | |
66 | ||
67 | To simplify this pass, removing basic blocks and dead code | |
68 | is left to CFG cleanup and DCE. */ | |
69 | ||
70 | ||
71 | /* Recognize a if-then-else CFG pattern starting to match with the | |
72 | COND_BB basic-block containing the COND_EXPR. The recognized | |
73 | then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
74 | *THEN_BB and/or *ELSE_BB are already set, they are required to | |
75 | match the then and else basic-blocks to make the pattern match. | |
76 | Returns true if the pattern matched, false otherwise. */ | |
77 | ||
78 | static bool | |
79 | recognize_if_then_else (basic_block cond_bb, | |
80 | basic_block *then_bb, basic_block *else_bb) | |
81 | { | |
82 | edge t, e; | |
83 | ||
84 | if (EDGE_COUNT (cond_bb->succs) != 2) | |
85 | return false; | |
86 | ||
87 | /* Find the then/else edges. */ | |
88 | t = EDGE_SUCC (cond_bb, 0); | |
89 | e = EDGE_SUCC (cond_bb, 1); | |
90 | if (!(t->flags & EDGE_TRUE_VALUE)) | |
a4f59596 | 91 | std::swap (t, e); |
8530c7be | 92 | if (!(t->flags & EDGE_TRUE_VALUE) |
93 | || !(e->flags & EDGE_FALSE_VALUE)) | |
94 | return false; | |
95 | ||
96 | /* Check if the edge destinations point to the required block. */ | |
97 | if (*then_bb | |
98 | && t->dest != *then_bb) | |
99 | return false; | |
100 | if (*else_bb | |
101 | && e->dest != *else_bb) | |
102 | return false; | |
103 | ||
104 | if (!*then_bb) | |
105 | *then_bb = t->dest; | |
106 | if (!*else_bb) | |
107 | *else_bb = e->dest; | |
108 | ||
109 | return true; | |
110 | } | |
111 | ||
112 | /* Verify if the basic block BB does not have side-effects. Return | |
113 | true in this case, else false. */ | |
114 | ||
115 | static bool | |
116 | bb_no_side_effects_p (basic_block bb) | |
117 | { | |
75a70cf9 | 118 | gimple_stmt_iterator gsi; |
8530c7be | 119 | |
75a70cf9 | 120 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
8530c7be | 121 | { |
42acab1c | 122 | gimple *stmt = gsi_stmt (gsi); |
8530c7be | 123 | |
ab8f103c | 124 | if (is_gimple_debug (stmt)) |
125 | continue; | |
126 | ||
b523dd6d | 127 | if (gimple_has_side_effects (stmt) |
4883b250 | 128 | || gimple_uses_undefined_value_p (stmt) |
ab8f103c | 129 | || gimple_could_trap_p (stmt) |
3cb15094 | 130 | || gimple_vuse (stmt) |
131 | /* const calls don't match any of the above, yet they could | |
132 | still have some side-effects - they could contain | |
133 | gimple_could_trap_p statements, like floating point | |
134 | exceptions or integer division by zero. See PR70586. | |
135 | FIXME: perhaps gimple_has_side_effects or gimple_could_trap_p | |
136 | should handle this. */ | |
137 | || is_gimple_call (stmt)) | |
8530c7be | 138 | return false; |
139 | } | |
140 | ||
141 | return true; | |
142 | } | |
143 | ||
9202fd6a | 144 | /* Return true if BB is an empty forwarder block to TO_BB. */ |
145 | ||
146 | static bool | |
147 | forwarder_block_to (basic_block bb, basic_block to_bb) | |
148 | { | |
149 | return empty_block_p (bb) | |
150 | && single_succ_p (bb) | |
151 | && single_succ (bb) == to_bb; | |
152 | } | |
153 | ||
8530c7be | 154 | /* Verify if all PHI node arguments in DEST for edges from BB1 or |
155 | BB2 to DEST are the same. This makes the CFG merge point | |
156 | free from side-effects. Return true in this case, else false. */ | |
157 | ||
158 | static bool | |
159 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
160 | { | |
161 | edge e1 = find_edge (bb1, dest); | |
162 | edge e2 = find_edge (bb2, dest); | |
1a91d914 | 163 | gphi_iterator gsi; |
164 | gphi *phi; | |
8530c7be | 165 | |
75a70cf9 | 166 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
167 | { | |
1a91d914 | 168 | phi = gsi.phi (); |
75a70cf9 | 169 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), |
170 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
171 | return false; | |
172 | } | |
8530c7be | 173 | |
174 | return true; | |
175 | } | |
176 | ||
c9686d06 | 177 | /* Return the best representative SSA name for CANDIDATE which is used |
178 | in a bit test. */ | |
179 | ||
180 | static tree | |
181 | get_name_for_bit_test (tree candidate) | |
182 | { | |
183 | /* Skip single-use names in favor of using the name from a | |
184 | non-widening conversion definition. */ | |
185 | if (TREE_CODE (candidate) == SSA_NAME | |
186 | && has_single_use (candidate)) | |
187 | { | |
42acab1c | 188 | gimple *def_stmt = SSA_NAME_DEF_STMT (candidate); |
75a70cf9 | 189 | if (is_gimple_assign (def_stmt) |
854e8953 | 190 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
c9686d06 | 191 | { |
75a70cf9 | 192 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
193 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
194 | return gimple_assign_rhs1 (def_stmt); | |
c9686d06 | 195 | } |
196 | } | |
197 | ||
198 | return candidate; | |
199 | } | |
200 | ||
75a70cf9 | 201 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
8530c7be | 202 | statements. Store the name being tested in *NAME and the bit |
75a70cf9 | 203 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
8530c7be | 204 | Returns true if the pattern matched, false otherwise. */ |
205 | ||
206 | static bool | |
1a91d914 | 207 | recognize_single_bit_test (gcond *cond, tree *name, tree *bit, bool inv) |
8530c7be | 208 | { |
42acab1c | 209 | gimple *stmt; |
8530c7be | 210 | |
211 | /* Get at the definition of the result of the bit test. */ | |
6e6b952b | 212 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
75a70cf9 | 213 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
214 | || !integer_zerop (gimple_cond_rhs (cond))) | |
8530c7be | 215 | return false; |
75a70cf9 | 216 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
217 | if (!is_gimple_assign (stmt)) | |
8530c7be | 218 | return false; |
8530c7be | 219 | |
220 | /* Look at which bit is tested. One form to recognize is | |
221 | D.1985_5 = state_3(D) >> control1_4(D); | |
222 | D.1986_6 = (int) D.1985_5; | |
223 | D.1987_7 = op0 & 1; | |
224 | if (D.1987_7 != 0) */ | |
75a70cf9 | 225 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
226 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
227 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
8530c7be | 228 | { |
75a70cf9 | 229 | tree orig_name = gimple_assign_rhs1 (stmt); |
d9022390 | 230 | |
231 | /* Look through copies and conversions to eventually | |
232 | find the stmt that computes the shift. */ | |
75a70cf9 | 233 | stmt = SSA_NAME_DEF_STMT (orig_name); |
234 | ||
235 | while (is_gimple_assign (stmt) | |
854e8953 | 236 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
237 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
48331bf4 | 238 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))) |
239 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
854e8953 | 240 | || gimple_assign_ssa_name_copy_p (stmt))) |
241 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
8530c7be | 242 | |
d9022390 | 243 | /* If we found such, decompose it. */ |
75a70cf9 | 244 | if (is_gimple_assign (stmt) |
245 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
8530c7be | 246 | { |
247 | /* op0 & (1 << op1) */ | |
75a70cf9 | 248 | *bit = gimple_assign_rhs2 (stmt); |
249 | *name = gimple_assign_rhs1 (stmt); | |
8530c7be | 250 | } |
251 | else | |
252 | { | |
253 | /* t & 1 */ | |
d9022390 | 254 | *bit = integer_zero_node; |
c9686d06 | 255 | *name = get_name_for_bit_test (orig_name); |
8530c7be | 256 | } |
257 | ||
258 | return true; | |
259 | } | |
260 | ||
261 | /* Another form is | |
262 | D.1987_7 = op0 & (1 << CST) | |
263 | if (D.1987_7 != 0) */ | |
75a70cf9 | 264 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
265 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
266 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
8530c7be | 267 | { |
75a70cf9 | 268 | *name = gimple_assign_rhs1 (stmt); |
8530c7be | 269 | *bit = build_int_cst (integer_type_node, |
75a70cf9 | 270 | tree_log2 (gimple_assign_rhs2 (stmt))); |
8530c7be | 271 | return true; |
272 | } | |
273 | ||
274 | /* Another form is | |
275 | D.1986_6 = 1 << control1_4(D) | |
276 | D.1987_7 = op0 & D.1986_6 | |
277 | if (D.1987_7 != 0) */ | |
75a70cf9 | 278 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
279 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
280 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
8530c7be | 281 | { |
42acab1c | 282 | gimple *tmp; |
8530c7be | 283 | |
284 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
285 | specifying expression. */ | |
75a70cf9 | 286 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
287 | if (is_gimple_assign (tmp) | |
288 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
289 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
8530c7be | 290 | { |
75a70cf9 | 291 | *name = gimple_assign_rhs2 (stmt); |
292 | *bit = gimple_assign_rhs2 (tmp); | |
8530c7be | 293 | return true; |
294 | } | |
295 | ||
75a70cf9 | 296 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
297 | if (is_gimple_assign (tmp) | |
298 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
299 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
8530c7be | 300 | { |
75a70cf9 | 301 | *name = gimple_assign_rhs1 (stmt); |
302 | *bit = gimple_assign_rhs2 (tmp); | |
8530c7be | 303 | return true; |
304 | } | |
305 | } | |
306 | ||
307 | return false; | |
308 | } | |
309 | ||
75a70cf9 | 310 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
8530c7be | 311 | statements. Store the name being tested in *NAME and the bits |
312 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
313 | Returns true if the pattern matched, false otherwise. */ | |
314 | ||
315 | static bool | |
1a91d914 | 316 | recognize_bits_test (gcond *cond, tree *name, tree *bits, bool inv) |
8530c7be | 317 | { |
42acab1c | 318 | gimple *stmt; |
8530c7be | 319 | |
320 | /* Get at the definition of the result of the bit test. */ | |
6e6b952b | 321 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
75a70cf9 | 322 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
323 | || !integer_zerop (gimple_cond_rhs (cond))) | |
8530c7be | 324 | return false; |
75a70cf9 | 325 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
326 | if (!is_gimple_assign (stmt) | |
327 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
8530c7be | 328 | return false; |
329 | ||
75a70cf9 | 330 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
331 | *bits = gimple_assign_rhs2 (stmt); | |
8530c7be | 332 | |
333 | return true; | |
334 | } | |
335 | ||
f56c861e | 336 | |
337 | /* Update profile after code in outer_cond_bb was adjusted so | |
338 | outer_cond_bb has no condition. */ | |
339 | ||
340 | static void | |
341 | update_profile_after_ifcombine (basic_block inner_cond_bb, | |
342 | basic_block outer_cond_bb) | |
343 | { | |
344 | edge outer_to_inner = find_edge (outer_cond_bb, inner_cond_bb); | |
345 | edge outer2 = (EDGE_SUCC (outer_cond_bb, 0) == outer_to_inner | |
346 | ? EDGE_SUCC (outer_cond_bb, 1) | |
347 | : EDGE_SUCC (outer_cond_bb, 0)); | |
348 | edge inner_taken = EDGE_SUCC (inner_cond_bb, 0); | |
349 | edge inner_not_taken = EDGE_SUCC (inner_cond_bb, 1); | |
350 | ||
351 | if (inner_taken->dest != outer2->dest) | |
352 | std::swap (inner_taken, inner_not_taken); | |
353 | gcc_assert (inner_taken->dest == outer2->dest); | |
354 | ||
355 | /* In the following we assume that inner_cond_bb has single predecessor. */ | |
356 | gcc_assert (single_pred_p (inner_cond_bb)); | |
357 | ||
358 | /* Path outer_cond_bb->(outer2) needs to be merged into path | |
359 | outer_cond_bb->(outer_to_inner)->inner_cond_bb->(inner_taken) | |
360 | and probability of inner_not_taken updated. */ | |
361 | ||
f56c861e | 362 | inner_cond_bb->count = outer_cond_bb->count; |
f56c861e | 363 | |
02fa1530 | 364 | /* Handle special case where inner_taken probability is always. In this case |
365 | we know that the overall outcome will be always as well, but combining | |
366 | probabilities will be conservative because it does not know that | |
367 | outer2->probability is inverse of outer_to_inner->probability. */ | |
368 | if (inner_taken->probability == profile_probability::always ()) | |
369 | ; | |
370 | else | |
371 | inner_taken->probability = outer2->probability + outer_to_inner->probability | |
372 | * inner_taken->probability; | |
720cfc43 | 373 | inner_not_taken->probability = profile_probability::always () |
f56c861e | 374 | - inner_taken->probability; |
375 | ||
720cfc43 | 376 | outer_to_inner->probability = profile_probability::always (); |
720cfc43 | 377 | outer2->probability = profile_probability::never (); |
f56c861e | 378 | } |
379 | ||
8530c7be | 380 | /* If-convert on a and pattern with a common else block. The inner |
381 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
6e6b952b | 382 | inner_inv, outer_inv and result_inv indicate whether the conditions |
383 | are inverted. | |
8530c7be | 384 | Returns true if the edges to the common else basic-block were merged. */ |
385 | ||
386 | static bool | |
6e6b952b | 387 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
388 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
8530c7be | 389 | { |
75a70cf9 | 390 | gimple_stmt_iterator gsi; |
42acab1c | 391 | gimple *inner_stmt, *outer_stmt; |
1a91d914 | 392 | gcond *inner_cond, *outer_cond; |
6e6b952b | 393 | tree name1, name2, bit1, bit2, bits1, bits2; |
8530c7be | 394 | |
1a91d914 | 395 | inner_stmt = last_stmt (inner_cond_bb); |
396 | if (!inner_stmt | |
397 | || gimple_code (inner_stmt) != GIMPLE_COND) | |
8530c7be | 398 | return false; |
1a91d914 | 399 | inner_cond = as_a <gcond *> (inner_stmt); |
8530c7be | 400 | |
1a91d914 | 401 | outer_stmt = last_stmt (outer_cond_bb); |
402 | if (!outer_stmt | |
403 | || gimple_code (outer_stmt) != GIMPLE_COND) | |
8530c7be | 404 | return false; |
1a91d914 | 405 | outer_cond = as_a <gcond *> (outer_stmt); |
8530c7be | 406 | |
407 | /* See if we test a single bit of the same name in both tests. In | |
408 | that case remove the outer test, merging both else edges, | |
409 | and change the inner one to test for | |
410 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
6e6b952b | 411 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
412 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
8530c7be | 413 | && name1 == name2) |
414 | { | |
415 | tree t, t2; | |
416 | ||
417 | /* Do it. */ | |
75a70cf9 | 418 | gsi = gsi_for_stmt (inner_cond); |
8530c7be | 419 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
9289fc25 | 420 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
8530c7be | 421 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
9289fc25 | 422 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
8530c7be | 423 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
75a70cf9 | 424 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
425 | true, GSI_SAME_STMT); | |
8530c7be | 426 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
75a70cf9 | 427 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
428 | true, GSI_SAME_STMT); | |
6e6b952b | 429 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
430 | boolean_type_node, t2, t); | |
b611dd5f | 431 | t = canonicalize_cond_expr_cond (t); |
432 | if (!t) | |
433 | return false; | |
75a70cf9 | 434 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 435 | update_stmt (inner_cond); |
436 | ||
437 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 438 | gimple_cond_set_condition_from_tree (outer_cond, |
439 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 440 | update_stmt (outer_cond); |
441 | ||
f56c861e | 442 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
443 | ||
8530c7be | 444 | if (dump_file) |
445 | { | |
446 | fprintf (dump_file, "optimizing double bit test to "); | |
1ffa4346 | 447 | print_generic_expr (dump_file, name1); |
8530c7be | 448 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); |
1ffa4346 | 449 | print_generic_expr (dump_file, bit1); |
8530c7be | 450 | fprintf (dump_file, ") | (1 << "); |
1ffa4346 | 451 | print_generic_expr (dump_file, bit2); |
8530c7be | 452 | fprintf (dump_file, ")\n"); |
453 | } | |
454 | ||
455 | return true; | |
456 | } | |
457 | ||
8530c7be | 458 | /* See if we have two bit tests of the same name in both tests. |
459 | In that case remove the outer test and change the inner one to | |
460 | test for name & (bits1 | bits2) != 0. */ | |
6e6b952b | 461 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
462 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
8530c7be | 463 | { |
75a70cf9 | 464 | gimple_stmt_iterator gsi; |
8530c7be | 465 | tree t; |
466 | ||
467 | /* Find the common name which is bit-tested. */ | |
468 | if (name1 == name2) | |
469 | ; | |
470 | else if (bits1 == bits2) | |
471 | { | |
dfcf26a5 | 472 | std::swap (name2, bits2); |
473 | std::swap (name1, bits1); | |
8530c7be | 474 | } |
475 | else if (name1 == bits2) | |
dfcf26a5 | 476 | std::swap (name2, bits2); |
8530c7be | 477 | else if (bits1 == name2) |
dfcf26a5 | 478 | std::swap (name1, bits1); |
8530c7be | 479 | else |
480 | return false; | |
481 | ||
2a8d660d | 482 | /* As we strip non-widening conversions in finding a common |
483 | name that is tested make sure to end up with an integral | |
484 | type for building the bit operations. */ | |
485 | if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
486 | >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
487 | { | |
488 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
489 | name1 = fold_convert (TREE_TYPE (bits1), name1); | |
490 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
491 | bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
492 | } | |
493 | else | |
494 | { | |
495 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
496 | name1 = fold_convert (TREE_TYPE (bits2), name1); | |
497 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
498 | bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
499 | } | |
500 | ||
8530c7be | 501 | /* Do it. */ |
75a70cf9 | 502 | gsi = gsi_for_stmt (inner_cond); |
8530c7be | 503 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); |
75a70cf9 | 504 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
505 | true, GSI_SAME_STMT); | |
8530c7be | 506 | t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
75a70cf9 | 507 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
508 | true, GSI_SAME_STMT); | |
6e6b952b | 509 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
75a70cf9 | 510 | build_int_cst (TREE_TYPE (t), 0)); |
b611dd5f | 511 | t = canonicalize_cond_expr_cond (t); |
512 | if (!t) | |
513 | return false; | |
75a70cf9 | 514 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 515 | update_stmt (inner_cond); |
516 | ||
517 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 518 | gimple_cond_set_condition_from_tree (outer_cond, |
519 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 520 | update_stmt (outer_cond); |
f56c861e | 521 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
8530c7be | 522 | |
523 | if (dump_file) | |
524 | { | |
525 | fprintf (dump_file, "optimizing bits or bits test to "); | |
1ffa4346 | 526 | print_generic_expr (dump_file, name1); |
8530c7be | 527 | fprintf (dump_file, " & T != 0\nwith temporary T = "); |
1ffa4346 | 528 | print_generic_expr (dump_file, bits1); |
8530c7be | 529 | fprintf (dump_file, " | "); |
1ffa4346 | 530 | print_generic_expr (dump_file, bits2); |
8530c7be | 531 | fprintf (dump_file, "\n"); |
532 | } | |
533 | ||
534 | return true; | |
535 | } | |
536 | ||
6e6b952b | 537 | /* See if we have two comparisons that we can merge into one. */ |
538 | else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
c82d157a | 539 | && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
8530c7be | 540 | { |
8530c7be | 541 | tree t; |
6e6b952b | 542 | enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
543 | enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
544 | ||
545 | /* Invert comparisons if necessary (and possible). */ | |
546 | if (inner_inv) | |
547 | inner_cond_code = invert_tree_comparison (inner_cond_code, | |
93633022 | 548 | HONOR_NANS (gimple_cond_lhs (inner_cond))); |
6e6b952b | 549 | if (inner_cond_code == ERROR_MARK) |
550 | return false; | |
551 | if (outer_inv) | |
552 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
93633022 | 553 | HONOR_NANS (gimple_cond_lhs (outer_cond))); |
6e6b952b | 554 | if (outer_cond_code == ERROR_MARK) |
555 | return false; | |
556 | /* Don't return false so fast, try maybe_fold_or_comparisons? */ | |
8530c7be | 557 | |
6e6b952b | 558 | if (!(t = maybe_fold_and_comparisons (inner_cond_code, |
559 | gimple_cond_lhs (inner_cond), | |
560 | gimple_cond_rhs (inner_cond), | |
561 | outer_cond_code, | |
562 | gimple_cond_lhs (outer_cond), | |
563 | gimple_cond_rhs (outer_cond)))) | |
b4c65f30 | 564 | { |
565 | tree t1, t2; | |
566 | gimple_stmt_iterator gsi; | |
8aa5cb12 | 567 | bool logical_op_non_short_circuit = LOGICAL_OP_NON_SHORT_CIRCUIT; |
568 | if (PARAM_VALUE (PARAM_LOGICAL_OP_NON_SHORT_CIRCUIT) != -1) | |
569 | logical_op_non_short_circuit | |
570 | = PARAM_VALUE (PARAM_LOGICAL_OP_NON_SHORT_CIRCUIT); | |
571 | if (!logical_op_non_short_circuit || flag_sanitize_coverage) | |
b4c65f30 | 572 | return false; |
573 | /* Only do this optimization if the inner bb contains only the conditional. */ | |
574 | if (!gsi_one_before_end_p (gsi_start_nondebug_after_labels_bb (inner_cond_bb))) | |
575 | return false; | |
576 | t1 = fold_build2_loc (gimple_location (inner_cond), | |
577 | inner_cond_code, | |
578 | boolean_type_node, | |
579 | gimple_cond_lhs (inner_cond), | |
580 | gimple_cond_rhs (inner_cond)); | |
581 | t2 = fold_build2_loc (gimple_location (outer_cond), | |
582 | outer_cond_code, | |
583 | boolean_type_node, | |
584 | gimple_cond_lhs (outer_cond), | |
585 | gimple_cond_rhs (outer_cond)); | |
586 | t = fold_build2_loc (gimple_location (inner_cond), | |
587 | TRUTH_AND_EXPR, boolean_type_node, t1, t2); | |
588 | if (result_inv) | |
589 | { | |
590 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
591 | result_inv = false; | |
592 | } | |
593 | gsi = gsi_for_stmt (inner_cond); | |
594 | t = force_gimple_operand_gsi_1 (&gsi, t, is_gimple_condexpr, NULL, true, | |
595 | GSI_SAME_STMT); | |
596 | } | |
6e6b952b | 597 | if (result_inv) |
598 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
a7392604 | 599 | t = canonicalize_cond_expr_cond (t); |
600 | if (!t) | |
601 | return false; | |
75a70cf9 | 602 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 603 | update_stmt (inner_cond); |
604 | ||
605 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 606 | gimple_cond_set_condition_from_tree (outer_cond, |
607 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 608 | update_stmt (outer_cond); |
f56c861e | 609 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
8530c7be | 610 | |
611 | if (dump_file) | |
612 | { | |
613 | fprintf (dump_file, "optimizing two comparisons to "); | |
1ffa4346 | 614 | print_generic_expr (dump_file, t); |
8530c7be | 615 | fprintf (dump_file, "\n"); |
616 | } | |
617 | ||
618 | return true; | |
619 | } | |
620 | ||
621 | return false; | |
622 | } | |
623 | ||
9202fd6a | 624 | /* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and |
625 | dispatch to the appropriate if-conversion helper for a particular | |
626 | set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. | |
627 | PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ | |
628 | ||
629 | static bool | |
630 | tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, | |
631 | basic_block then_bb, basic_block else_bb, | |
632 | basic_block phi_pred_bb) | |
633 | { | |
634 | /* The && form is characterized by a common else_bb with | |
635 | the two edges leading to it mergable. The latter is | |
636 | guaranteed by matching PHI arguments in the else_bb and | |
637 | the inner cond_bb having no side-effects. */ | |
638 | if (phi_pred_bb != else_bb | |
639 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
c66cf0b7 | 640 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) |
9202fd6a | 641 | { |
642 | /* We have | |
643 | <outer_cond_bb> | |
644 | if (q) goto inner_cond_bb; else goto else_bb; | |
645 | <inner_cond_bb> | |
646 | if (p) goto ...; else goto else_bb; | |
647 | ... | |
648 | <else_bb> | |
649 | ... | |
650 | */ | |
651 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, | |
652 | false); | |
653 | } | |
654 | ||
655 | /* And a version where the outer condition is negated. */ | |
656 | if (phi_pred_bb != else_bb | |
657 | && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
c66cf0b7 | 658 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) |
9202fd6a | 659 | { |
660 | /* We have | |
661 | <outer_cond_bb> | |
662 | if (q) goto else_bb; else goto inner_cond_bb; | |
663 | <inner_cond_bb> | |
664 | if (p) goto ...; else goto else_bb; | |
665 | ... | |
666 | <else_bb> | |
667 | ... | |
668 | */ | |
669 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
670 | false); | |
671 | } | |
672 | ||
673 | /* The || form is characterized by a common then_bb with the | |
674 | two edges leading to it mergable. The latter is guaranteed | |
675 | by matching PHI arguments in the then_bb and the inner cond_bb | |
676 | having no side-effects. */ | |
677 | if (phi_pred_bb != then_bb | |
678 | && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
c66cf0b7 | 679 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) |
9202fd6a | 680 | { |
681 | /* We have | |
682 | <outer_cond_bb> | |
683 | if (q) goto then_bb; else goto inner_cond_bb; | |
684 | <inner_cond_bb> | |
685 | if (q) goto then_bb; else goto ...; | |
686 | <then_bb> | |
687 | ... | |
688 | */ | |
689 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, | |
690 | true); | |
691 | } | |
692 | ||
693 | /* And a version where the outer condition is negated. */ | |
694 | if (phi_pred_bb != then_bb | |
695 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
c66cf0b7 | 696 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) |
9202fd6a | 697 | { |
698 | /* We have | |
699 | <outer_cond_bb> | |
700 | if (q) goto inner_cond_bb; else goto then_bb; | |
701 | <inner_cond_bb> | |
702 | if (q) goto then_bb; else goto ...; | |
703 | <then_bb> | |
704 | ... | |
705 | */ | |
706 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
707 | true); | |
708 | } | |
709 | ||
710 | return false; | |
711 | } | |
712 | ||
8530c7be | 713 | /* Recognize a CFG pattern and dispatch to the appropriate |
714 | if-conversion helper. We start with BB as the innermost | |
715 | worker basic-block. Returns true if a transformation was done. */ | |
716 | ||
717 | static bool | |
718 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
719 | { | |
720 | basic_block then_bb = NULL, else_bb = NULL; | |
721 | ||
722 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
723 | return false; | |
724 | ||
725 | /* Recognize && and || of two conditions with a common | |
726 | then/else block which entry edges we can merge. That is: | |
727 | if (a || b) | |
728 | ; | |
729 | and | |
730 | if (a && b) | |
731 | ; | |
732 | This requires a single predecessor of the inner cond_bb. */ | |
c66cf0b7 | 733 | if (single_pred_p (inner_cond_bb) |
734 | && bb_no_side_effects_p (inner_cond_bb)) | |
8530c7be | 735 | { |
736 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
737 | ||
9202fd6a | 738 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, |
739 | then_bb, else_bb, inner_cond_bb)) | |
740 | return true; | |
6e6b952b | 741 | |
9202fd6a | 742 | if (forwarder_block_to (else_bb, then_bb)) |
6e6b952b | 743 | { |
9202fd6a | 744 | /* Other possibilities for the && form, if else_bb is |
745 | empty forwarder block to then_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, else_bb)) | |
752 | return true; | |
8530c7be | 753 | } |
9202fd6a | 754 | else if (forwarder_block_to (then_bb, else_bb)) |
6e6b952b | 755 | { |
9202fd6a | 756 | /* Other possibilities for the || form, if then_bb is |
757 | empty forwarder block to else_bb. Compared to the above simpler | |
758 | forms this can be treated as if then_bb and else_bb were swapped, | |
759 | and the corresponding inner_cond_bb not inverted because of that. | |
760 | For same_phi_args_p we look at equality of arguments between | |
761 | edge from outer_cond_bb and the forwarder block. */ | |
762 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
763 | then_bb, then_bb)) | |
764 | return true; | |
8530c7be | 765 | } |
766 | } | |
767 | ||
768 | return false; | |
769 | } | |
770 | ||
771 | /* Main entry for the tree if-conversion pass. */ | |
772 | ||
65b0537f | 773 | namespace { |
774 | ||
775 | const pass_data pass_data_tree_ifcombine = | |
776 | { | |
777 | GIMPLE_PASS, /* type */ | |
778 | "ifcombine", /* name */ | |
779 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 780 | TV_TREE_IFCOMBINE, /* tv_id */ |
781 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
782 | 0, /* properties_provided */ | |
783 | 0, /* properties_destroyed */ | |
784 | 0, /* todo_flags_start */ | |
8b88439e | 785 | TODO_update_ssa, /* todo_flags_finish */ |
65b0537f | 786 | }; |
787 | ||
788 | class pass_tree_ifcombine : public gimple_opt_pass | |
789 | { | |
790 | public: | |
791 | pass_tree_ifcombine (gcc::context *ctxt) | |
792 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
793 | {} | |
794 | ||
795 | /* opt_pass methods: */ | |
796 | virtual unsigned int execute (function *); | |
797 | ||
798 | }; // class pass_tree_ifcombine | |
799 | ||
800 | unsigned int | |
801 | pass_tree_ifcombine::execute (function *fun) | |
8530c7be | 802 | { |
803 | basic_block *bbs; | |
804 | bool cfg_changed = false; | |
805 | int i; | |
806 | ||
ba4d2b2f | 807 | bbs = single_pred_before_succ_order (); |
8a245b9d | 808 | calculate_dominance_info (CDI_DOMINATORS); |
8530c7be | 809 | |
b4c65f30 | 810 | /* Search every basic block for COND_EXPR we may be able to optimize. |
811 | ||
812 | We walk the blocks in order that guarantees that a block with | |
813 | a single predecessor is processed after the predecessor. | |
814 | This ensures that we collapse outter ifs before visiting the | |
815 | inner ones, and also that we do not try to visit a removed | |
816 | block. This is opposite of PHI-OPT, because we cascade the | |
817 | combining rather than cascading PHIs. */ | |
65b0537f | 818 | for (i = n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) |
8530c7be | 819 | { |
820 | basic_block bb = bbs[i]; | |
42acab1c | 821 | gimple *stmt = last_stmt (bb); |
8530c7be | 822 | |
823 | if (stmt | |
75a70cf9 | 824 | && gimple_code (stmt) == GIMPLE_COND) |
ace499f6 | 825 | if (tree_ssa_ifcombine_bb (bb)) |
826 | { | |
827 | /* Clear range info from all stmts in BB which is now executed | |
828 | conditional on a always true/false condition. */ | |
43725011 | 829 | reset_flow_sensitive_info_in_bb (bb); |
ace499f6 | 830 | cfg_changed |= true; |
831 | } | |
8530c7be | 832 | } |
833 | ||
834 | free (bbs); | |
835 | ||
836 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
837 | } | |
838 | ||
cbe8bda8 | 839 | } // anon namespace |
840 | ||
841 | gimple_opt_pass * | |
842 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
843 | { | |
844 | return new pass_tree_ifcombine (ctxt); | |
845 | } |