Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-ifcombine.c @ 131:84e7813d76e9
gcc-8.2
| author | mir3636 |
|---|---|
| date | Thu, 25 Oct 2018 07:37:49 +0900 |
| parents | 04ced10e8804 |
| children | 1830386684a0 |
| rev | line source |
|---|---|
| 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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77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
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423 t = canonicalize_cond_expr_cond (t); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
424 if (!t) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
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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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 | |
|
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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 } |