Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-switch-conversion.c @ 127:4c56639505ff
fix function.c and add CbC-example Makefile
| author | mir3636 |
|---|---|
| date | Wed, 11 Apr 2018 18:46:58 +0900 |
| parents | 04ced10e8804 |
| children | 84e7813d76e9 |
| rev | line source |
|---|---|
| 111 | 1 /* Lower GIMPLE_SWITCH expressions to something more efficient than |
| 2 a jump table. | |
| 3 Copyright (C) 2006-2017 Free Software Foundation, Inc. | |
| 0 | 4 |
| 5 This file is part of GCC. | |
| 6 | |
| 7 GCC is free software; you can redistribute it and/or modify it | |
| 8 under the terms of the GNU General Public License as published by the | |
| 9 Free Software Foundation; either version 3, or (at your option) any | |
| 10 later version. | |
| 11 | |
| 12 GCC is distributed in the hope that it will be useful, but WITHOUT | |
| 13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 15 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, write to the Free | |
| 19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA | |
| 20 02110-1301, USA. */ | |
| 21 | |
| 111 | 22 /* This file handles the lowering of GIMPLE_SWITCH to an indexed |
| 23 load, or a series of bit-test-and-branch expressions. */ | |
| 24 | |
| 25 #include "config.h" | |
| 26 #include "system.h" | |
| 27 #include "coretypes.h" | |
| 28 #include "backend.h" | |
| 29 #include "insn-codes.h" | |
| 30 #include "rtl.h" | |
| 31 #include "tree.h" | |
| 32 #include "gimple.h" | |
| 33 #include "cfghooks.h" | |
| 34 #include "tree-pass.h" | |
| 35 #include "ssa.h" | |
| 36 #include "optabs-tree.h" | |
| 37 #include "cgraph.h" | |
| 38 #include "gimple-pretty-print.h" | |
| 39 #include "params.h" | |
| 40 #include "fold-const.h" | |
| 41 #include "varasm.h" | |
| 42 #include "stor-layout.h" | |
| 43 #include "cfganal.h" | |
| 44 #include "gimplify.h" | |
| 45 #include "gimple-iterator.h" | |
| 46 #include "gimplify-me.h" | |
| 47 #include "tree-cfg.h" | |
| 48 #include "cfgloop.h" | |
| 49 #include "alloc-pool.h" | |
| 50 #include "target.h" | |
| 51 #include "tree-into-ssa.h" | |
| 52 | |
| 53 /* ??? For lang_hooks.types.type_for_mode, but is there a word_mode | |
| 54 type in the GIMPLE type system that is language-independent? */ | |
| 55 #include "langhooks.h" | |
| 56 | |
| 57 | |
| 58 /* Maximum number of case bit tests. | |
| 59 FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and | |
| 60 targetm.case_values_threshold(), or be its own param. */ | |
| 61 #define MAX_CASE_BIT_TESTS 3 | |
| 62 | |
| 63 /* Split the basic block at the statement pointed to by GSIP, and insert | |
| 64 a branch to the target basic block of E_TRUE conditional on tree | |
| 65 expression COND. | |
| 66 | |
| 67 It is assumed that there is already an edge from the to-be-split | |
| 68 basic block to E_TRUE->dest block. This edge is removed, and the | |
| 69 profile information on the edge is re-used for the new conditional | |
| 70 jump. | |
| 71 | |
| 72 The CFG is updated. The dominator tree will not be valid after | |
| 73 this transformation, but the immediate dominators are updated if | |
| 74 UPDATE_DOMINATORS is true. | |
| 75 | |
| 76 Returns the newly created basic block. */ | |
| 77 | |
| 78 static basic_block | |
| 79 hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip, | |
| 80 tree cond, edge e_true, | |
| 81 bool update_dominators) | |
| 82 { | |
| 83 tree tmp; | |
| 84 gcond *cond_stmt; | |
| 85 edge e_false; | |
| 86 basic_block new_bb, split_bb = gsi_bb (*gsip); | |
| 87 bool dominated_e_true = false; | |
| 88 | |
| 89 gcc_assert (e_true->src == split_bb); | |
| 90 | |
| 91 if (update_dominators | |
| 92 && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb) | |
| 93 dominated_e_true = true; | |
| 94 | |
| 95 tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL, | |
| 96 /*before=*/true, GSI_SAME_STMT); | |
| 97 cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE); | |
| 98 gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT); | |
| 99 | |
| 100 e_false = split_block (split_bb, cond_stmt); | |
| 101 new_bb = e_false->dest; | |
| 102 redirect_edge_pred (e_true, split_bb); | |
| 103 | |
| 104 e_true->flags &= ~EDGE_FALLTHRU; | |
| 105 e_true->flags |= EDGE_TRUE_VALUE; | |
| 106 | |
| 107 e_false->flags &= ~EDGE_FALLTHRU; | |
| 108 e_false->flags |= EDGE_FALSE_VALUE; | |
| 109 e_false->probability = e_true->probability.invert (); | |
| 110 new_bb->count = e_false->count (); | |
| 111 | |
| 112 if (update_dominators) | |
| 113 { | |
| 114 if (dominated_e_true) | |
| 115 set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb); | |
| 116 set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb); | |
| 117 } | |
| 118 | |
| 119 return new_bb; | |
| 120 } | |
| 121 | |
| 122 | |
| 123 /* Return true if a switch should be expanded as a bit test. | |
| 124 RANGE is the difference between highest and lowest case. | |
| 125 UNIQ is number of unique case node targets, not counting the default case. | |
| 126 COUNT is the number of comparisons needed, not counting the default case. */ | |
| 127 | |
| 128 static bool | |
| 129 expand_switch_using_bit_tests_p (tree range, | |
| 130 unsigned int uniq, | |
| 131 unsigned int count, bool speed_p) | |
| 132 { | |
| 133 return (((uniq == 1 && count >= 3) | |
| 134 || (uniq == 2 && count >= 5) | |
| 135 || (uniq == 3 && count >= 6)) | |
| 136 && lshift_cheap_p (speed_p) | |
| 137 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 | |
| 138 && compare_tree_int (range, 0) > 0); | |
| 139 } | |
| 140 | |
| 141 /* Implement switch statements with bit tests | |
| 142 | |
| 143 A GIMPLE switch statement can be expanded to a short sequence of bit-wise | |
| 144 comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)" | |
| 145 where CST and MINVAL are integer constants. This is better than a series | |
| 146 of compare-and-banch insns in some cases, e.g. we can implement: | |
| 147 | |
| 148 if ((x==4) || (x==6) || (x==9) || (x==11)) | |
| 149 | |
| 150 as a single bit test: | |
| 151 | |
| 152 if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11))) | |
| 153 | |
| 154 This transformation is only applied if the number of case targets is small, | |
| 155 if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are | |
| 156 performed in "word_mode". | |
| 157 | |
| 158 The following example shows the code the transformation generates: | |
| 159 | |
| 160 int bar(int x) | |
| 161 { | |
| 162 switch (x) | |
| 163 { | |
| 164 case '0': case '1': case '2': case '3': case '4': | |
| 165 case '5': case '6': case '7': case '8': case '9': | |
| 166 case 'A': case 'B': case 'C': case 'D': case 'E': | |
| 167 case 'F': | |
| 168 return 1; | |
| 169 } | |
| 170 return 0; | |
| 171 } | |
| 172 | |
| 173 ==> | |
| 174 | |
| 175 bar (int x) | |
| 176 { | |
| 177 tmp1 = x - 48; | |
| 178 if (tmp1 > (70 - 48)) goto L2; | |
| 179 tmp2 = 1 << tmp1; | |
| 180 tmp3 = 0b11111100000001111111111; | |
| 181 if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2; | |
| 182 L1: | |
| 183 return 1; | |
| 184 L2: | |
| 185 return 0; | |
| 186 } | |
| 187 | |
| 188 TODO: There are still some improvements to this transformation that could | |
| 189 be implemented: | |
| 190 | |
| 191 * A narrower mode than word_mode could be used if that is cheaper, e.g. | |
| 192 for x86_64 where a narrower-mode shift may result in smaller code. | |
| 193 | |
| 194 * The compounded constant could be shifted rather than the one. The | |
| 195 test would be either on the sign bit or on the least significant bit, | |
| 196 depending on the direction of the shift. On some machines, the test | |
| 197 for the branch would be free if the bit to test is already set by the | |
| 198 shift operation. | |
| 199 | |
| 200 This transformation was contributed by Roger Sayle, see this e-mail: | |
| 201 http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html | |
| 202 */ | |
| 203 | |
| 204 /* A case_bit_test represents a set of case nodes that may be | |
| 205 selected from using a bit-wise comparison. HI and LO hold | |
| 206 the integer to be tested against, TARGET_EDGE contains the | |
| 207 edge to the basic block to jump to upon success and BITS | |
| 208 counts the number of case nodes handled by this test, | |
| 209 typically the number of bits set in HI:LO. The LABEL field | |
| 210 is used to quickly identify all cases in this set without | |
| 211 looking at label_to_block for every case label. */ | |
| 212 | |
| 213 struct case_bit_test | |
| 214 { | |
| 215 wide_int mask; | |
| 216 edge target_edge; | |
| 217 tree label; | |
| 218 int bits; | |
| 219 }; | |
| 220 | |
| 221 /* Comparison function for qsort to order bit tests by decreasing | |
| 222 probability of execution. Our best guess comes from a measured | |
| 223 profile. If the profile counts are equal, break even on the | |
| 224 number of case nodes, i.e. the node with the most cases gets | |
| 225 tested first. | |
| 226 | |
| 227 TODO: Actually this currently runs before a profile is available. | |
| 228 Therefore the case-as-bit-tests transformation should be done | |
| 229 later in the pass pipeline, or something along the lines of | |
| 230 "Efficient and effective branch reordering using profile data" | |
| 231 (Yang et. al., 2002) should be implemented (although, how good | |
| 232 is a paper is called "Efficient and effective ..." when the | |
| 233 latter is implied by the former, but oh well...). */ | |
| 234 | |
| 235 static int | |
| 236 case_bit_test_cmp (const void *p1, const void *p2) | |
| 237 { | |
| 238 const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
| 239 const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
| 240 | |
| 241 if (d2->target_edge->count () < d1->target_edge->count ()) | |
| 242 return -1; | |
| 243 if (d2->target_edge->count () > d1->target_edge->count ()) | |
| 244 return 1; | |
| 245 if (d2->bits != d1->bits) | |
| 246 return d2->bits - d1->bits; | |
| 247 | |
| 248 /* Stabilize the sort. */ | |
| 249 return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label); | |
| 250 } | |
| 251 | |
| 252 /* Expand a switch statement by a short sequence of bit-wise | |
| 253 comparisons. "switch(x)" is effectively converted into | |
| 254 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
| 255 integer constants. | |
| 256 | |
| 257 INDEX_EXPR is the value being switched on. | |
| 258 | |
| 259 MINVAL is the lowest case value of in the case nodes, | |
| 260 and RANGE is highest value minus MINVAL. MINVAL and RANGE | |
| 261 are not guaranteed to be of the same type as INDEX_EXPR | |
| 262 (the gimplifier doesn't change the type of case label values, | |
| 263 and MINVAL and RANGE are derived from those values). | |
| 264 MAXVAL is MINVAL + RANGE. | |
| 265 | |
| 266 There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
| 267 node targets. */ | |
| 268 | |
| 269 static void | |
| 270 emit_case_bit_tests (gswitch *swtch, tree index_expr, | |
| 271 tree minval, tree range, tree maxval) | |
| 272 { | |
| 273 struct case_bit_test test[MAX_CASE_BIT_TESTS] = { {} }; | |
| 274 unsigned int i, j, k; | |
| 275 unsigned int count; | |
| 276 | |
| 277 basic_block switch_bb = gimple_bb (swtch); | |
| 278 basic_block default_bb, new_default_bb, new_bb; | |
| 279 edge default_edge; | |
| 280 bool update_dom = dom_info_available_p (CDI_DOMINATORS); | |
| 281 | |
| 282 vec<basic_block> bbs_to_fix_dom = vNULL; | |
| 283 | |
| 284 tree index_type = TREE_TYPE (index_expr); | |
| 285 tree unsigned_index_type = unsigned_type_for (index_type); | |
| 286 unsigned int branch_num = gimple_switch_num_labels (swtch); | |
| 287 | |
| 288 gimple_stmt_iterator gsi; | |
| 289 gassign *shift_stmt; | |
| 290 | |
| 291 tree idx, tmp, csui; | |
| 292 tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); | |
| 293 tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); | |
| 294 tree word_mode_one = fold_convert (word_type_node, integer_one_node); | |
| 295 int prec = TYPE_PRECISION (word_type_node); | |
| 296 wide_int wone = wi::one (prec); | |
| 297 | |
| 298 /* Get the edge for the default case. */ | |
| 299 tmp = gimple_switch_default_label (swtch); | |
| 300 default_bb = label_to_block (CASE_LABEL (tmp)); | |
| 301 default_edge = find_edge (switch_bb, default_bb); | |
| 302 | |
| 303 /* Go through all case labels, and collect the case labels, profile | |
| 304 counts, and other information we need to build the branch tests. */ | |
| 305 count = 0; | |
| 306 for (i = 1; i < branch_num; i++) | |
| 307 { | |
| 308 unsigned int lo, hi; | |
| 309 tree cs = gimple_switch_label (swtch, i); | |
| 310 tree label = CASE_LABEL (cs); | |
| 311 edge e = find_edge (switch_bb, label_to_block (label)); | |
| 312 for (k = 0; k < count; k++) | |
| 313 if (e == test[k].target_edge) | |
| 314 break; | |
| 315 | |
| 316 if (k == count) | |
| 317 { | |
| 318 gcc_checking_assert (count < MAX_CASE_BIT_TESTS); | |
| 319 test[k].mask = wi::zero (prec); | |
| 320 test[k].target_edge = e; | |
| 321 test[k].label = label; | |
| 322 test[k].bits = 1; | |
| 323 count++; | |
| 324 } | |
| 325 else | |
| 326 test[k].bits++; | |
| 327 | |
| 328 lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, | |
| 329 CASE_LOW (cs), minval)); | |
| 330 if (CASE_HIGH (cs) == NULL_TREE) | |
| 331 hi = lo; | |
| 332 else | |
| 333 hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, | |
| 334 CASE_HIGH (cs), minval)); | |
| 335 | |
| 336 for (j = lo; j <= hi; j++) | |
| 337 test[k].mask |= wi::lshift (wone, j); | |
| 338 } | |
| 339 | |
| 340 qsort (test, count, sizeof (*test), case_bit_test_cmp); | |
| 341 | |
| 342 /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of | |
| 343 the minval subtractions, but it might make the mask constants more | |
| 344 expensive. So, compare the costs. */ | |
| 345 if (compare_tree_int (minval, 0) > 0 | |
| 346 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
| 347 { | |
| 348 int cost_diff; | |
| 349 HOST_WIDE_INT m = tree_to_uhwi (minval); | |
| 350 rtx reg = gen_raw_REG (word_mode, 10000); | |
| 351 bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); | |
| 352 cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, | |
| 353 GEN_INT (-m)), speed_p); | |
| 354 for (i = 0; i < count; i++) | |
| 355 { | |
| 356 rtx r = immed_wide_int_const (test[i].mask, word_mode); | |
| 357 cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), | |
| 358 word_mode, speed_p); | |
| 359 r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); | |
| 360 cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), | |
| 361 word_mode, speed_p); | |
| 362 } | |
| 363 if (cost_diff > 0) | |
| 364 { | |
| 365 for (i = 0; i < count; i++) | |
| 366 test[i].mask = wi::lshift (test[i].mask, m); | |
| 367 minval = build_zero_cst (TREE_TYPE (minval)); | |
| 368 range = maxval; | |
| 369 } | |
| 370 } | |
| 371 | |
| 372 /* We generate two jumps to the default case label. | |
| 373 Split the default edge, so that we don't have to do any PHI node | |
| 374 updating. */ | |
| 375 new_default_bb = split_edge (default_edge); | |
| 376 | |
| 377 if (update_dom) | |
| 378 { | |
| 379 bbs_to_fix_dom.create (10); | |
| 380 bbs_to_fix_dom.quick_push (switch_bb); | |
| 381 bbs_to_fix_dom.quick_push (default_bb); | |
| 382 bbs_to_fix_dom.quick_push (new_default_bb); | |
| 383 } | |
| 384 | |
| 385 /* Now build the test-and-branch code. */ | |
| 386 | |
| 387 gsi = gsi_last_bb (switch_bb); | |
| 388 | |
| 389 /* idx = (unsigned)x - minval. */ | |
| 390 idx = fold_convert (unsigned_index_type, index_expr); | |
| 391 idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx, | |
| 392 fold_convert (unsigned_index_type, minval)); | |
| 393 idx = force_gimple_operand_gsi (&gsi, idx, | |
| 394 /*simple=*/true, NULL_TREE, | |
| 395 /*before=*/true, GSI_SAME_STMT); | |
| 396 | |
| 397 /* if (idx > range) goto default */ | |
| 398 range = force_gimple_operand_gsi (&gsi, | |
| 399 fold_convert (unsigned_index_type, range), | |
| 400 /*simple=*/true, NULL_TREE, | |
| 401 /*before=*/true, GSI_SAME_STMT); | |
| 402 tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); | |
| 403 new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom); | |
| 404 if (update_dom) | |
| 405 bbs_to_fix_dom.quick_push (new_bb); | |
| 406 gcc_assert (gimple_bb (swtch) == new_bb); | |
| 407 gsi = gsi_last_bb (new_bb); | |
| 408 | |
| 409 /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors | |
| 410 of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */ | |
| 411 if (update_dom) | |
| 412 { | |
| 413 vec<basic_block> dom_bbs; | |
| 414 basic_block dom_son; | |
| 415 | |
| 416 dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb); | |
| 417 FOR_EACH_VEC_ELT (dom_bbs, i, dom_son) | |
| 418 { | |
| 419 edge e = find_edge (new_bb, dom_son); | |
| 420 if (e && single_pred_p (e->dest)) | |
| 421 continue; | |
| 422 set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb); | |
| 423 bbs_to_fix_dom.safe_push (dom_son); | |
| 424 } | |
| 425 dom_bbs.release (); | |
| 426 } | |
| 427 | |
| 428 /* csui = (1 << (word_mode) idx) */ | |
| 429 csui = make_ssa_name (word_type_node); | |
| 430 tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one, | |
| 431 fold_convert (word_type_node, idx)); | |
| 432 tmp = force_gimple_operand_gsi (&gsi, tmp, | |
| 433 /*simple=*/false, NULL_TREE, | |
| 434 /*before=*/true, GSI_SAME_STMT); | |
| 435 shift_stmt = gimple_build_assign (csui, tmp); | |
| 436 gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT); | |
| 437 update_stmt (shift_stmt); | |
| 438 | |
| 439 /* for each unique set of cases: | |
| 440 if (const & csui) goto target */ | |
| 441 for (k = 0; k < count; k++) | |
| 442 { | |
| 443 tmp = wide_int_to_tree (word_type_node, test[k].mask); | |
| 444 tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); | |
| 445 tmp = force_gimple_operand_gsi (&gsi, tmp, | |
| 446 /*simple=*/true, NULL_TREE, | |
| 447 /*before=*/true, GSI_SAME_STMT); | |
| 448 tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero); | |
| 449 new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge, | |
| 450 update_dom); | |
| 451 if (update_dom) | |
| 452 bbs_to_fix_dom.safe_push (new_bb); | |
| 453 gcc_assert (gimple_bb (swtch) == new_bb); | |
| 454 gsi = gsi_last_bb (new_bb); | |
| 455 } | |
| 456 | |
| 457 /* We should have removed all edges now. */ | |
| 458 gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0); | |
| 459 | |
| 460 /* If nothing matched, go to the default label. */ | |
| 461 make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU); | |
| 462 | |
| 463 /* The GIMPLE_SWITCH is now redundant. */ | |
| 464 gsi_remove (&gsi, true); | |
| 465 | |
| 466 if (update_dom) | |
| 467 { | |
| 468 /* Fix up the dominator tree. */ | |
| 469 iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
| 470 bbs_to_fix_dom.release (); | |
| 471 } | |
| 472 } | |
| 473 | |
| 0 | 474 /* |
| 475 Switch initialization conversion | |
| 476 | |
| 477 The following pass changes simple initializations of scalars in a switch | |
| 111 | 478 statement into initializations from a static array. Obviously, the values |
| 479 must be constant and known at compile time and a default branch must be | |
| 0 | 480 provided. For example, the following code: |
| 481 | |
| 482 int a,b; | |
| 483 | |
| 484 switch (argc) | |
| 485 { | |
| 486 case 1: | |
| 487 case 2: | |
| 488 a_1 = 8; | |
| 489 b_1 = 6; | |
| 490 break; | |
| 491 case 3: | |
| 492 a_2 = 9; | |
| 493 b_2 = 5; | |
| 494 break; | |
| 495 case 12: | |
| 496 a_3 = 10; | |
| 497 b_3 = 4; | |
| 498 break; | |
| 499 default: | |
| 500 a_4 = 16; | |
| 501 b_4 = 1; | |
| 111 | 502 break; |
| 0 | 503 } |
| 504 a_5 = PHI <a_1, a_2, a_3, a_4> | |
| 505 b_5 = PHI <b_1, b_2, b_3, b_4> | |
| 506 | |
| 507 | |
| 508 is changed into: | |
| 509 | |
| 510 static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4}; | |
| 511 static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16, | |
| 512 16, 16, 10}; | |
| 513 | |
| 514 if (((unsigned) argc) - 1 < 11) | |
| 515 { | |
| 516 a_6 = CSWTCH02[argc - 1]; | |
| 517 b_6 = CSWTCH01[argc - 1]; | |
| 518 } | |
| 519 else | |
| 520 { | |
| 521 a_7 = 16; | |
| 522 b_7 = 1; | |
| 523 } | |
| 111 | 524 a_5 = PHI <a_6, a_7> |
| 525 b_b = PHI <b_6, b_7> | |
| 0 | 526 |
| 527 There are further constraints. Specifically, the range of values across all | |
| 528 case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default | |
| 111 | 529 eight) times the number of the actual switch branches. |
| 530 | |
| 531 This transformation was contributed by Martin Jambor, see this e-mail: | |
| 532 http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */ | |
| 0 | 533 |
| 534 /* The main structure of the pass. */ | |
| 535 struct switch_conv_info | |
| 536 { | |
| 111 | 537 /* The expression used to decide the switch branch. */ |
| 0 | 538 tree index_expr; |
| 539 | |
| 111 | 540 /* The following integer constants store the minimum and maximum value |
| 541 covered by the case labels. */ | |
| 0 | 542 tree range_min; |
| 111 | 543 tree range_max; |
| 544 | |
| 545 /* The difference between the above two numbers. Stored here because it | |
| 546 is used in all the conversion heuristics, as well as for some of the | |
| 547 transformation, and it is expensive to re-compute it all the time. */ | |
| 0 | 548 tree range_size; |
| 549 | |
| 111 | 550 /* Basic block that contains the actual GIMPLE_SWITCH. */ |
| 0 | 551 basic_block switch_bb; |
| 552 | |
| 111 | 553 /* Basic block that is the target of the default case. */ |
| 554 basic_block default_bb; | |
| 555 | |
| 556 /* The single successor block of all branches out of the GIMPLE_SWITCH, | |
| 557 if such a block exists. Otherwise NULL. */ | |
| 0 | 558 basic_block final_bb; |
| 559 | |
| 111 | 560 /* The probability of the default edge in the replaced switch. */ |
| 561 profile_probability default_prob; | |
| 562 | |
| 563 /* The count of the default edge in the replaced switch. */ | |
| 564 profile_count default_count; | |
| 565 | |
| 566 /* Combined count of all other (non-default) edges in the replaced switch. */ | |
| 567 profile_count other_count; | |
| 568 | |
| 0 | 569 /* Number of phi nodes in the final bb (that we'll be replacing). */ |
| 570 int phi_count; | |
| 571 | |
| 572 /* Array of default values, in the same order as phi nodes. */ | |
| 573 tree *default_values; | |
| 574 | |
| 575 /* Constructors of new static arrays. */ | |
| 111 | 576 vec<constructor_elt, va_gc> **constructors; |
| 0 | 577 |
| 578 /* Array of ssa names that are initialized with a value from a new static | |
| 579 array. */ | |
| 580 tree *target_inbound_names; | |
| 581 | |
| 582 /* Array of ssa names that are initialized with the default value if the | |
| 583 switch expression is out of range. */ | |
| 584 tree *target_outbound_names; | |
| 585 | |
| 111 | 586 /* VOP SSA_NAME. */ |
| 587 tree target_vop; | |
| 0 | 588 |
| 589 /* The first load statement that loads a temporary from a new static array. | |
| 590 */ | |
| 111 | 591 gimple *arr_ref_first; |
| 0 | 592 |
| 593 /* The last load statement that loads a temporary from a new static array. */ | |
| 111 | 594 gimple *arr_ref_last; |
| 0 | 595 |
| 596 /* String reason why the case wasn't a good candidate that is written to the | |
| 597 dump file, if there is one. */ | |
| 598 const char *reason; | |
|
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599 |
| 111 | 600 /* True if default case is not used for any value between range_min and |
| 601 range_max inclusive. */ | |
| 602 bool contiguous_range; | |
| 603 | |
| 604 /* True if default case does not have the required shape for other case | |
| 605 labels. */ | |
| 606 bool default_case_nonstandard; | |
| 607 | |
|
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608 /* Parameters for expand_switch_using_bit_tests. Should be computed |
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609 the same way as in expand_case. */ |
| 111 | 610 unsigned int uniq; |
| 611 unsigned int count; | |
| 0 | 612 }; |
| 613 | |
| 111 | 614 /* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */ |
| 615 | |
| 616 static void | |
| 617 collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info) | |
| 618 { | |
| 619 unsigned int branch_num = gimple_switch_num_labels (swtch); | |
| 620 tree min_case, max_case; | |
| 621 unsigned int count, i; | |
| 622 edge e, e_default, e_first; | |
| 623 edge_iterator ei; | |
| 624 basic_block first; | |
| 625 | |
| 626 memset (info, 0, sizeof (*info)); | |
| 627 | |
| 628 /* The gimplifier has already sorted the cases by CASE_LOW and ensured there | |
| 629 is a default label which is the first in the vector. | |
| 630 Collect the bits we can deduce from the CFG. */ | |
| 631 info->index_expr = gimple_switch_index (swtch); | |
| 632 info->switch_bb = gimple_bb (swtch); | |
| 633 info->default_bb | |
| 634 = label_to_block (CASE_LABEL (gimple_switch_default_label (swtch))); | |
| 635 e_default = find_edge (info->switch_bb, info->default_bb); | |
| 636 info->default_prob = e_default->probability; | |
| 637 info->default_count = e_default->count (); | |
| 638 FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
| 639 if (e != e_default) | |
| 640 info->other_count += e->count (); | |
| 641 | |
| 642 /* Get upper and lower bounds of case values, and the covered range. */ | |
| 643 min_case = gimple_switch_label (swtch, 1); | |
| 644 max_case = gimple_switch_label (swtch, branch_num - 1); | |
| 645 | |
| 646 info->range_min = CASE_LOW (min_case); | |
| 647 if (CASE_HIGH (max_case) != NULL_TREE) | |
| 648 info->range_max = CASE_HIGH (max_case); | |
| 649 else | |
| 650 info->range_max = CASE_LOW (max_case); | |
| 651 | |
| 652 info->contiguous_range = true; | |
| 653 tree last = CASE_HIGH (min_case) ? CASE_HIGH (min_case) : info->range_min; | |
| 654 for (i = 2; i < branch_num; i++) | |
| 655 { | |
| 656 tree elt = gimple_switch_label (swtch, i); | |
| 657 if (wi::to_wide (last) + 1 != wi::to_wide (CASE_LOW (elt))) | |
| 658 { | |
| 659 info->contiguous_range = false; | |
| 660 break; | |
| 661 } | |
| 662 last = CASE_HIGH (elt) ? CASE_HIGH (elt) : CASE_LOW (elt); | |
| 663 } | |
| 664 | |
| 665 if (info->contiguous_range) | |
| 666 { | |
| 667 first = label_to_block (CASE_LABEL (gimple_switch_label (swtch, 1))); | |
| 668 e_first = find_edge (info->switch_bb, first); | |
| 669 } | |
| 670 else | |
| 671 { | |
| 672 first = info->default_bb; | |
| 673 e_first = e_default; | |
| 674 } | |
| 675 | |
| 676 /* See if there is one common successor block for all branch | |
| 677 targets. If it exists, record it in FINAL_BB. | |
| 678 Start with the destination of the first non-default case | |
| 679 if the range is contiguous and default case otherwise as | |
| 680 guess or its destination in case it is a forwarder block. */ | |
| 681 if (! single_pred_p (e_first->dest)) | |
| 682 info->final_bb = e_first->dest; | |
| 683 else if (single_succ_p (e_first->dest) | |
| 684 && ! single_pred_p (single_succ (e_first->dest))) | |
| 685 info->final_bb = single_succ (e_first->dest); | |
| 686 /* Require that all switch destinations are either that common | |
| 687 FINAL_BB or a forwarder to it, except for the default | |
| 688 case if contiguous range. */ | |
| 689 if (info->final_bb) | |
| 690 FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
| 691 { | |
| 692 if (e->dest == info->final_bb) | |
| 693 continue; | |
| 694 | |
| 695 if (single_pred_p (e->dest) | |
| 696 && single_succ_p (e->dest) | |
| 697 && single_succ (e->dest) == info->final_bb) | |
| 698 continue; | |
| 699 | |
| 700 if (e == e_default && info->contiguous_range) | |
| 701 { | |
| 702 info->default_case_nonstandard = true; | |
| 703 continue; | |
| 704 } | |
| 705 | |
| 706 info->final_bb = NULL; | |
| 707 break; | |
| 708 } | |
| 709 | |
| 710 info->range_size | |
| 711 = int_const_binop (MINUS_EXPR, info->range_max, info->range_min); | |
| 712 | |
| 713 /* Get a count of the number of case labels. Single-valued case labels | |
| 714 simply count as one, but a case range counts double, since it may | |
| 715 require two compares if it gets lowered as a branching tree. */ | |
| 716 count = 0; | |
| 717 for (i = 1; i < branch_num; i++) | |
| 718 { | |
| 719 tree elt = gimple_switch_label (swtch, i); | |
| 720 count++; | |
| 721 if (CASE_HIGH (elt) | |
| 722 && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt))) | |
| 723 count++; | |
| 724 } | |
| 725 info->count = count; | |
| 726 | |
| 727 /* Get the number of unique non-default targets out of the GIMPLE_SWITCH | |
| 728 block. Assume a CFG cleanup would have already removed degenerate | |
| 729 switch statements, this allows us to just use EDGE_COUNT. */ | |
| 730 info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1; | |
| 731 } | |
| 0 | 732 |
| 733 /* Checks whether the range given by individual case statements of the SWTCH | |
| 734 switch statement isn't too big and whether the number of branches actually | |
| 735 satisfies the size of the new array. */ | |
| 736 | |
| 737 static bool | |
| 111 | 738 check_range (struct switch_conv_info *info) |
| 0 | 739 { |
| 111 | 740 gcc_assert (info->range_size); |
| 741 if (!tree_fits_uhwi_p (info->range_size)) | |
| 0 | 742 { |
| 111 | 743 info->reason = "index range way too large or otherwise unusable"; |
| 0 | 744 return false; |
| 745 } | |
| 746 | |
| 111 | 747 if (tree_to_uhwi (info->range_size) |
| 748 > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO)) | |
| 0 | 749 { |
| 111 | 750 info->reason = "the maximum range-branch ratio exceeded"; |
| 0 | 751 return false; |
| 752 } | |
| 753 | |
| 754 return true; | |
| 755 } | |
| 756 | |
| 111 | 757 /* Checks whether all but the FINAL_BB basic blocks are empty. */ |
| 0 | 758 |
| 759 static bool | |
| 111 | 760 check_all_empty_except_final (struct switch_conv_info *info) |
| 0 | 761 { |
| 111 | 762 edge e, e_default = find_edge (info->switch_bb, info->default_bb); |
| 763 edge_iterator ei; | |
| 764 | |
| 765 FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
|
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766 { |
| 111 | 767 if (e->dest == info->final_bb) |
| 768 continue; | |
| 769 | |
| 770 if (!empty_block_p (e->dest)) | |
| 0 | 771 { |
| 111 | 772 if (info->contiguous_range && e == e_default) |
| 773 { | |
| 774 info->default_case_nonstandard = true; | |
| 775 continue; | |
| 776 } | |
| 777 | |
| 778 info->reason = "bad case - a non-final BB not empty"; | |
| 0 | 779 return false; |
| 780 } | |
| 781 } | |
| 782 | |
| 783 return true; | |
| 784 } | |
| 785 | |
| 786 /* This function checks whether all required values in phi nodes in final_bb | |
| 787 are constants. Required values are those that correspond to a basic block | |
| 788 which is a part of the examined switch statement. It returns true if the | |
| 789 phi nodes are OK, otherwise false. */ | |
| 790 | |
| 791 static bool | |
| 111 | 792 check_final_bb (gswitch *swtch, struct switch_conv_info *info) |
| 0 | 793 { |
| 111 | 794 gphi_iterator gsi; |
| 795 | |
| 796 info->phi_count = 0; | |
| 797 for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 0 | 798 { |
| 111 | 799 gphi *phi = gsi.phi (); |
| 0 | 800 unsigned int i; |
| 801 | |
| 111 | 802 if (virtual_operand_p (gimple_phi_result (phi))) |
| 803 continue; | |
| 804 | |
| 805 info->phi_count++; | |
| 0 | 806 |
| 807 for (i = 0; i < gimple_phi_num_args (phi); i++) | |
| 808 { | |
| 809 basic_block bb = gimple_phi_arg_edge (phi, i)->src; | |
| 810 | |
| 111 | 811 if (bb == info->switch_bb |
| 812 || (single_pred_p (bb) | |
| 813 && single_pred (bb) == info->switch_bb | |
| 814 && (!info->default_case_nonstandard | |
| 815 || empty_block_p (bb)))) | |
| 0 | 816 { |
| 817 tree reloc, val; | |
| 111 | 818 const char *reason = NULL; |
| 0 | 819 |
| 820 val = gimple_phi_arg_def (phi, i); | |
| 821 if (!is_gimple_ip_invariant (val)) | |
| 111 | 822 reason = "non-invariant value from a case"; |
| 823 else | |
| 0 | 824 { |
| 111 | 825 reloc = initializer_constant_valid_p (val, TREE_TYPE (val)); |
| 826 if ((flag_pic && reloc != null_pointer_node) | |
| 827 || (!flag_pic && reloc == NULL_TREE)) | |
| 828 { | |
| 829 if (reloc) | |
| 830 reason | |
| 831 = "value from a case would need runtime relocations"; | |
| 832 else | |
| 833 reason | |
| 834 = "value from a case is not a valid initializer"; | |
| 835 } | |
| 0 | 836 } |
| 111 | 837 if (reason) |
| 0 | 838 { |
| 111 | 839 /* For contiguous range, we can allow non-constant |
| 840 or one that needs relocation, as long as it is | |
| 841 only reachable from the default case. */ | |
| 842 if (bb == info->switch_bb) | |
| 843 bb = info->final_bb; | |
| 844 if (!info->contiguous_range || bb != info->default_bb) | |
| 845 { | |
| 846 info->reason = reason; | |
| 847 return false; | |
| 848 } | |
| 849 | |
| 850 unsigned int branch_num = gimple_switch_num_labels (swtch); | |
| 851 for (unsigned int i = 1; i < branch_num; i++) | |
| 852 { | |
| 853 tree lab = CASE_LABEL (gimple_switch_label (swtch, i)); | |
| 854 if (label_to_block (lab) == bb) | |
| 855 { | |
| 856 info->reason = reason; | |
| 857 return false; | |
| 858 } | |
| 859 } | |
| 860 info->default_case_nonstandard = true; | |
| 0 | 861 } |
| 862 } | |
| 863 } | |
| 864 } | |
| 865 | |
| 866 return true; | |
| 867 } | |
| 868 | |
| 869 /* The following function allocates default_values, target_{in,out}_names and | |
| 870 constructors arrays. The last one is also populated with pointers to | |
| 871 vectors that will become constructors of new arrays. */ | |
| 872 | |
| 873 static void | |
| 111 | 874 create_temp_arrays (struct switch_conv_info *info) |
| 0 | 875 { |
| 876 int i; | |
| 877 | |
| 111 | 878 info->default_values = XCNEWVEC (tree, info->phi_count * 3); |
| 879 /* ??? Macros do not support multi argument templates in their | |
| 880 argument list. We create a typedef to work around that problem. */ | |
| 881 typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc; | |
| 882 info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count); | |
| 883 info->target_inbound_names = info->default_values + info->phi_count; | |
| 884 info->target_outbound_names = info->target_inbound_names + info->phi_count; | |
| 885 for (i = 0; i < info->phi_count; i++) | |
| 886 vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1); | |
| 0 | 887 } |
| 888 | |
| 889 /* Free the arrays created by create_temp_arrays(). The vectors that are | |
| 890 created by that function are not freed here, however, because they have | |
| 891 already become constructors and must be preserved. */ | |
| 892 | |
| 893 static void | |
| 111 | 894 free_temp_arrays (struct switch_conv_info *info) |
| 0 | 895 { |
| 111 | 896 XDELETEVEC (info->constructors); |
| 897 XDELETEVEC (info->default_values); | |
| 0 | 898 } |
| 899 | |
| 900 /* Populate the array of default values in the order of phi nodes. | |
| 111 | 901 DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch |
| 902 if the range is non-contiguous or the default case has standard | |
| 903 structure, otherwise it is the first non-default case instead. */ | |
| 0 | 904 |
| 905 static void | |
| 111 | 906 gather_default_values (tree default_case, struct switch_conv_info *info) |
| 0 | 907 { |
| 111 | 908 gphi_iterator gsi; |
| 0 | 909 basic_block bb = label_to_block (CASE_LABEL (default_case)); |
| 910 edge e; | |
| 911 int i = 0; | |
| 912 | |
| 111 | 913 gcc_assert (CASE_LOW (default_case) == NULL_TREE |
| 914 || info->default_case_nonstandard); | |
| 915 | |
| 916 if (bb == info->final_bb) | |
| 917 e = find_edge (info->switch_bb, bb); | |
| 0 | 918 else |
| 919 e = single_succ_edge (bb); | |
| 920 | |
| 111 | 921 for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 0 | 922 { |
| 111 | 923 gphi *phi = gsi.phi (); |
| 924 if (virtual_operand_p (gimple_phi_result (phi))) | |
| 925 continue; | |
| 0 | 926 tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
| 927 gcc_assert (val); | |
| 111 | 928 info->default_values[i++] = val; |
| 0 | 929 } |
| 930 } | |
| 931 | |
| 932 /* The following function populates the vectors in the constructors array with | |
| 933 future contents of the static arrays. The vectors are populated in the | |
| 934 order of phi nodes. SWTCH is the switch statement being converted. */ | |
| 935 | |
| 936 static void | |
| 111 | 937 build_constructors (gswitch *swtch, struct switch_conv_info *info) |
| 0 | 938 { |
| 939 unsigned i, branch_num = gimple_switch_num_labels (swtch); | |
| 111 | 940 tree pos = info->range_min; |
| 941 tree pos_one = build_int_cst (TREE_TYPE (pos), 1); | |
| 0 | 942 |
| 943 for (i = 1; i < branch_num; i++) | |
| 944 { | |
| 945 tree cs = gimple_switch_label (swtch, i); | |
| 946 basic_block bb = label_to_block (CASE_LABEL (cs)); | |
| 947 edge e; | |
| 948 tree high; | |
| 111 | 949 gphi_iterator gsi; |
| 0 | 950 int j; |
| 951 | |
| 111 | 952 if (bb == info->final_bb) |
| 953 e = find_edge (info->switch_bb, bb); | |
| 0 | 954 else |
| 955 e = single_succ_edge (bb); | |
| 956 gcc_assert (e); | |
| 957 | |
| 958 while (tree_int_cst_lt (pos, CASE_LOW (cs))) | |
| 959 { | |
| 960 int k; | |
| 111 | 961 gcc_assert (!info->contiguous_range); |
| 962 for (k = 0; k < info->phi_count; k++) | |
| 0 | 963 { |
| 111 | 964 constructor_elt elt; |
| 965 | |
| 966 elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); | |
| 967 elt.value | |
| 968 = unshare_expr_without_location (info->default_values[k]); | |
| 969 info->constructors[k]->quick_push (elt); | |
| 0 | 970 } |
| 971 | |
| 111 | 972 pos = int_const_binop (PLUS_EXPR, pos, pos_one); |
| 0 | 973 } |
| 974 gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs))); | |
| 975 | |
| 976 j = 0; | |
| 977 if (CASE_HIGH (cs)) | |
| 978 high = CASE_HIGH (cs); | |
| 979 else | |
| 980 high = CASE_LOW (cs); | |
| 111 | 981 for (gsi = gsi_start_phis (info->final_bb); |
| 0 | 982 !gsi_end_p (gsi); gsi_next (&gsi)) |
| 983 { | |
| 111 | 984 gphi *phi = gsi.phi (); |
| 985 if (virtual_operand_p (gimple_phi_result (phi))) | |
| 986 continue; | |
| 0 | 987 tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
| 988 tree low = CASE_LOW (cs); | |
| 989 pos = CASE_LOW (cs); | |
| 990 | |
|
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991 do |
| 0 | 992 { |
| 111 | 993 constructor_elt elt; |
| 994 | |
| 995 elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); | |
| 996 elt.value = unshare_expr_without_location (val); | |
| 997 info->constructors[j]->quick_push (elt); | |
| 998 | |
| 999 pos = int_const_binop (PLUS_EXPR, pos, pos_one); | |
|
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1000 } while (!tree_int_cst_lt (high, pos) |
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1001 && tree_int_cst_lt (low, pos)); |
| 0 | 1002 j++; |
| 1003 } | |
| 1004 } | |
| 1005 } | |
| 1006 | |
|
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1007 /* If all values in the constructor vector are the same, return the value. |
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1008 Otherwise return NULL_TREE. Not supposed to be called for empty |
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1009 vectors. */ |
|
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1010 |
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1011 static tree |
| 111 | 1012 constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec) |
|
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1013 { |
|
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1014 unsigned int i; |
|
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1015 tree prev = NULL_TREE; |
|
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1016 constructor_elt *elt; |
|
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1017 |
| 111 | 1018 FOR_EACH_VEC_SAFE_ELT (vec, i, elt) |
|
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1019 { |
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1020 if (!prev) |
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1021 prev = elt->value; |
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1022 else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST)) |
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1023 return NULL_TREE; |
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1024 } |
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1025 return prev; |
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1026 } |
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1027 |
| 111 | 1028 /* Return type which should be used for array elements, either TYPE's |
| 1029 main variant or, for integral types, some smaller integral type | |
| 1030 that can still hold all the constants. */ | |
|
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1031 |
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1032 static tree |
| 111 | 1033 array_value_type (gswitch *swtch, tree type, int num, |
| 1034 struct switch_conv_info *info) | |
|
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1035 { |
| 111 | 1036 unsigned int i, len = vec_safe_length (info->constructors[num]); |
|
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1037 constructor_elt *elt; |
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1038 int sign = 0; |
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1039 tree smaller_type; |
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1040 |
| 111 | 1041 /* Types with alignments greater than their size can reach here, e.g. out of |
| 1042 SRA. We couldn't use these as an array component type so get back to the | |
| 1043 main variant first, which, for our purposes, is fine for other types as | |
| 1044 well. */ | |
| 1045 | |
| 1046 type = TYPE_MAIN_VARIANT (type); | |
| 1047 | |
|
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1048 if (!INTEGRAL_TYPE_P (type)) |
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1049 return type; |
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1050 |
| 111 | 1051 scalar_int_mode type_mode = SCALAR_INT_TYPE_MODE (type); |
| 1052 scalar_int_mode mode = get_narrowest_mode (type_mode); | |
| 1053 if (GET_MODE_SIZE (type_mode) <= GET_MODE_SIZE (mode)) | |
|
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1054 return type; |
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1055 |
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1056 if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32)) |
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1057 return type; |
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1058 |
| 111 | 1059 FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
|
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1060 { |
| 111 | 1061 wide_int cst; |
|
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1062 |
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1063 if (TREE_CODE (elt->value) != INTEGER_CST) |
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1064 return type; |
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1065 |
| 111 | 1066 cst = wi::to_wide (elt->value); |
|
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1067 while (1) |
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1068 { |
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1069 unsigned int prec = GET_MODE_BITSIZE (mode); |
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1070 if (prec > HOST_BITS_PER_WIDE_INT) |
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1071 return type; |
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1072 |
| 111 | 1073 if (sign >= 0 && cst == wi::zext (cst, prec)) |
|
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1074 { |
| 111 | 1075 if (sign == 0 && cst == wi::sext (cst, prec)) |
|
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1076 break; |
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1077 sign = 1; |
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1078 break; |
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1079 } |
| 111 | 1080 if (sign <= 0 && cst == wi::sext (cst, prec)) |
|
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1081 { |
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1082 sign = -1; |
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1083 break; |
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1084 } |
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1085 |
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1086 if (sign == 1) |
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1087 sign = 0; |
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1088 |
| 111 | 1089 if (!GET_MODE_WIDER_MODE (mode).exists (&mode) |
| 1090 || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (type_mode)) | |
|
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1091 return type; |
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1092 } |
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1093 } |
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1094 |
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1095 if (sign == 0) |
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1096 sign = TYPE_UNSIGNED (type) ? 1 : -1; |
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1097 smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0); |
| 111 | 1098 if (GET_MODE_SIZE (type_mode) |
| 1099 <= GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (smaller_type))) | |
|
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1100 return type; |
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1101 |
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1102 return smaller_type; |
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1103 } |
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1104 |
| 0 | 1105 /* Create an appropriate array type and declaration and assemble a static array |
| 1106 variable. Also create a load statement that initializes the variable in | |
| 1107 question with a value from the static array. SWTCH is the switch statement | |
| 1108 being converted, NUM is the index to arrays of constructors, default values | |
| 1109 and target SSA names for this particular array. ARR_INDEX_TYPE is the type | |
| 1110 of the index of the new array, PHI is the phi node of the final BB that | |
| 1111 corresponds to the value that will be loaded from the created array. TIDX | |
|
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1112 is an ssa name of a temporary variable holding the index for loads from the |
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1113 new array. */ |
| 0 | 1114 |
| 1115 static void | |
| 111 | 1116 build_one_array (gswitch *swtch, int num, tree arr_index_type, |
| 1117 gphi *phi, tree tidx, struct switch_conv_info *info) | |
| 0 | 1118 { |
|
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1119 tree name, cst; |
| 111 | 1120 gimple *load; |
|
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1121 gimple_stmt_iterator gsi = gsi_for_stmt (swtch); |
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1122 location_t loc = gimple_location (swtch); |
| 0 | 1123 |
| 111 | 1124 gcc_assert (info->default_values[num]); |
| 1125 | |
| 1126 name = copy_ssa_name (PHI_RESULT (phi)); | |
| 1127 info->target_inbound_names[num] = name; | |
| 1128 | |
| 1129 cst = constructor_contains_same_values_p (info->constructors[num]); | |
|
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1130 if (cst) |
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1131 load = gimple_build_assign (name, cst); |
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1132 else |
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1133 { |
|
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1134 tree array_type, ctor, decl, value_type, fetch, default_type; |
|
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1135 |
| 111 | 1136 default_type = TREE_TYPE (info->default_values[num]); |
| 1137 value_type = array_value_type (swtch, default_type, num, info); | |
|
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1138 array_type = build_array_type (value_type, arr_index_type); |
|
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1139 if (default_type != value_type) |
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1140 { |
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1141 unsigned int i; |
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1142 constructor_elt *elt; |
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1143 |
| 111 | 1144 FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
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1145 elt->value = fold_convert (value_type, elt->value); |
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1146 } |
| 111 | 1147 ctor = build_constructor (array_type, info->constructors[num]); |
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1148 TREE_CONSTANT (ctor) = true; |
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1149 TREE_STATIC (ctor) = true; |
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1150 |
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1151 decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type); |
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1152 TREE_STATIC (decl) = 1; |
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1153 DECL_INITIAL (decl) = ctor; |
| 0 | 1154 |
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1155 DECL_NAME (decl) = create_tmp_var_name ("CSWTCH"); |
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1156 DECL_ARTIFICIAL (decl) = 1; |
| 111 | 1157 DECL_IGNORED_P (decl) = 1; |
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1158 TREE_CONSTANT (decl) = 1; |
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1159 TREE_READONLY (decl) = 1; |
| 111 | 1160 DECL_IGNORED_P (decl) = 1; |
| 1161 varpool_node::finalize_decl (decl); | |
|
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1162 |
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1163 fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE, |
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1164 NULL_TREE); |
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1165 if (default_type != value_type) |
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1166 { |
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1167 fetch = fold_convert (default_type, fetch); |
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1168 fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE, |
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1169 true, GSI_SAME_STMT); |
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1170 } |
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1171 load = gimple_build_assign (name, fetch); |
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1172 } |
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1173 |
| 0 | 1174 gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
|
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1175 update_stmt (load); |
| 111 | 1176 info->arr_ref_last = load; |
| 0 | 1177 } |
| 1178 | |
| 1179 /* Builds and initializes static arrays initialized with values gathered from | |
| 1180 the SWTCH switch statement. Also creates statements that load values from | |
| 1181 them. */ | |
| 1182 | |
| 1183 static void | |
| 111 | 1184 build_arrays (gswitch *swtch, struct switch_conv_info *info) |
| 0 | 1185 { |
| 1186 tree arr_index_type; | |
| 111 | 1187 tree tidx, sub, utype; |
| 1188 gimple *stmt; | |
| 0 | 1189 gimple_stmt_iterator gsi; |
| 111 | 1190 gphi_iterator gpi; |
| 0 | 1191 int i; |
|
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1192 location_t loc = gimple_location (swtch); |
| 0 | 1193 |
| 1194 gsi = gsi_for_stmt (swtch); | |
| 1195 | |
| 111 | 1196 /* Make sure we do not generate arithmetics in a subrange. */ |
| 1197 utype = TREE_TYPE (info->index_expr); | |
| 1198 if (TREE_TYPE (utype)) | |
| 1199 utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1); | |
| 1200 else | |
| 1201 utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1); | |
| 1202 | |
| 1203 arr_index_type = build_index_type (info->range_size); | |
| 1204 tidx = make_ssa_name (utype); | |
| 1205 sub = fold_build2_loc (loc, MINUS_EXPR, utype, | |
| 1206 fold_convert_loc (loc, utype, info->index_expr), | |
| 1207 fold_convert_loc (loc, utype, info->range_min)); | |
|
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1208 sub = force_gimple_operand_gsi (&gsi, sub, |
| 0 | 1209 false, NULL, true, GSI_SAME_STMT); |
| 1210 stmt = gimple_build_assign (tidx, sub); | |
| 1211 | |
| 1212 gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); | |
|
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1213 update_stmt (stmt); |
| 111 | 1214 info->arr_ref_first = stmt; |
| 1215 | |
| 1216 for (gpi = gsi_start_phis (info->final_bb), i = 0; | |
| 1217 !gsi_end_p (gpi); gsi_next (&gpi)) | |
| 1218 { | |
| 1219 gphi *phi = gpi.phi (); | |
| 1220 if (!virtual_operand_p (gimple_phi_result (phi))) | |
| 1221 build_one_array (swtch, i++, arr_index_type, phi, tidx, info); | |
| 1222 else | |
| 1223 { | |
| 1224 edge e; | |
| 1225 edge_iterator ei; | |
| 1226 FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
| 1227 { | |
| 1228 if (e->dest == info->final_bb) | |
| 1229 break; | |
| 1230 if (!info->default_case_nonstandard | |
| 1231 || e->dest != info->default_bb) | |
| 1232 { | |
| 1233 e = single_succ_edge (e->dest); | |
| 1234 break; | |
| 1235 } | |
| 1236 } | |
| 1237 gcc_assert (e && e->dest == info->final_bb); | |
| 1238 info->target_vop = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
| 1239 } | |
| 1240 } | |
| 0 | 1241 } |
| 1242 | |
| 1243 /* Generates and appropriately inserts loads of default values at the position | |
| 1244 given by BSI. Returns the last inserted statement. */ | |
| 1245 | |
| 111 | 1246 static gassign * |
| 1247 gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info) | |
| 0 | 1248 { |
| 1249 int i; | |
| 111 | 1250 gassign *assign = NULL; |
| 1251 | |
| 1252 for (i = 0; i < info->phi_count; i++) | |
| 0 | 1253 { |
| 111 | 1254 tree name = copy_ssa_name (info->target_inbound_names[i]); |
| 1255 info->target_outbound_names[i] = name; | |
| 1256 assign = gimple_build_assign (name, info->default_values[i]); | |
| 0 | 1257 gsi_insert_before (gsi, assign, GSI_SAME_STMT); |
|
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1258 update_stmt (assign); |
| 0 | 1259 } |
| 1260 return assign; | |
| 1261 } | |
| 1262 | |
| 1263 /* Deletes the unused bbs and edges that now contain the switch statement and | |
| 1264 its empty branch bbs. BBD is the now dead BB containing the original switch | |
| 1265 statement, FINAL is the last BB of the converted switch statement (in terms | |
| 1266 of succession). */ | |
| 1267 | |
| 1268 static void | |
| 111 | 1269 prune_bbs (basic_block bbd, basic_block final, basic_block default_bb) |
| 0 | 1270 { |
| 1271 edge_iterator ei; | |
| 1272 edge e; | |
| 1273 | |
| 1274 for (ei = ei_start (bbd->succs); (e = ei_safe_edge (ei)); ) | |
| 1275 { | |
| 1276 basic_block bb; | |
| 1277 bb = e->dest; | |
| 1278 remove_edge (e); | |
| 111 | 1279 if (bb != final && bb != default_bb) |
| 0 | 1280 delete_basic_block (bb); |
| 1281 } | |
| 1282 delete_basic_block (bbd); | |
| 1283 } | |
| 1284 | |
| 1285 /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge | |
| 1286 from the basic block loading values from an array and E2F from the basic | |
| 1287 block loading default values. BBF is the last switch basic block (see the | |
| 1288 bbf description in the comment below). */ | |
| 1289 | |
| 1290 static void | |
| 111 | 1291 fix_phi_nodes (edge e1f, edge e2f, basic_block bbf, |
| 1292 struct switch_conv_info *info) | |
| 0 | 1293 { |
| 111 | 1294 gphi_iterator gsi; |
| 0 | 1295 int i; |
| 1296 | |
| 1297 for (gsi = gsi_start_phis (bbf), i = 0; | |
| 111 | 1298 !gsi_end_p (gsi); gsi_next (&gsi)) |
| 0 | 1299 { |
| 111 | 1300 gphi *phi = gsi.phi (); |
| 1301 tree inbound, outbound; | |
| 1302 if (virtual_operand_p (gimple_phi_result (phi))) | |
| 1303 inbound = outbound = info->target_vop; | |
| 1304 else | |
| 1305 { | |
| 1306 inbound = info->target_inbound_names[i]; | |
| 1307 outbound = info->target_outbound_names[i++]; | |
| 1308 } | |
| 1309 add_phi_arg (phi, inbound, e1f, UNKNOWN_LOCATION); | |
| 1310 if (!info->default_case_nonstandard) | |
| 1311 add_phi_arg (phi, outbound, e2f, UNKNOWN_LOCATION); | |
| 0 | 1312 } |
| 1313 } | |
| 1314 | |
| 1315 /* Creates a check whether the switch expression value actually falls into the | |
| 1316 range given by all the cases. If it does not, the temporaries are loaded | |
| 1317 with default values instead. SWTCH is the switch statement being converted. | |
| 1318 | |
| 1319 bb0 is the bb with the switch statement, however, we'll end it with a | |
| 1320 condition instead. | |
| 1321 | |
| 1322 bb1 is the bb to be used when the range check went ok. It is derived from | |
| 1323 the switch BB | |
| 1324 | |
| 1325 bb2 is the bb taken when the expression evaluated outside of the range | |
| 1326 covered by the created arrays. It is populated by loads of default | |
| 1327 values. | |
| 1328 | |
| 1329 bbF is a fall through for both bb1 and bb2 and contains exactly what | |
| 1330 originally followed the switch statement. | |
| 1331 | |
| 1332 bbD contains the switch statement (in the end). It is unreachable but we | |
| 1333 still need to strip off its edges. | |
| 1334 */ | |
| 1335 | |
| 1336 static void | |
| 111 | 1337 gen_inbound_check (gswitch *swtch, struct switch_conv_info *info) |
| 0 | 1338 { |
|
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1339 tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION); |
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1340 tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION); |
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1341 tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION); |
| 111 | 1342 glabel *label1, *label2, *label3; |
| 1343 tree utype, tidx; | |
| 0 | 1344 tree bound; |
| 1345 | |
| 111 | 1346 gcond *cond_stmt; |
| 1347 | |
| 1348 gassign *last_assign = NULL; | |
| 0 | 1349 gimple_stmt_iterator gsi; |
| 1350 basic_block bb0, bb1, bb2, bbf, bbd; | |
| 111 | 1351 edge e01 = NULL, e02, e21, e1d, e1f, e2f; |
|
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1352 location_t loc = gimple_location (swtch); |
| 0 | 1353 |
| 111 | 1354 gcc_assert (info->default_values); |
| 1355 | |
| 0 | 1356 bb0 = gimple_bb (swtch); |
| 1357 | |
| 111 | 1358 tidx = gimple_assign_lhs (info->arr_ref_first); |
| 1359 utype = TREE_TYPE (tidx); | |
| 0 | 1360 |
| 1361 /* (end of) block 0 */ | |
| 111 | 1362 gsi = gsi_for_stmt (info->arr_ref_first); |
| 1363 gsi_next (&gsi); | |
| 1364 | |
| 1365 bound = fold_convert_loc (loc, utype, info->range_size); | |
| 1366 cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE); | |
| 0 | 1367 gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT); |
|
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1368 update_stmt (cond_stmt); |
| 0 | 1369 |
| 1370 /* block 2 */ | |
| 111 | 1371 if (!info->default_case_nonstandard) |
| 1372 { | |
| 1373 label2 = gimple_build_label (label_decl2); | |
| 1374 gsi_insert_before (&gsi, label2, GSI_SAME_STMT); | |
| 1375 last_assign = gen_def_assigns (&gsi, info); | |
| 1376 } | |
| 0 | 1377 |
| 1378 /* block 1 */ | |
| 1379 label1 = gimple_build_label (label_decl1); | |
| 1380 gsi_insert_before (&gsi, label1, GSI_SAME_STMT); | |
| 1381 | |
| 1382 /* block F */ | |
| 111 | 1383 gsi = gsi_start_bb (info->final_bb); |
| 0 | 1384 label3 = gimple_build_label (label_decl3); |
| 1385 gsi_insert_before (&gsi, label3, GSI_SAME_STMT); | |
| 1386 | |
| 1387 /* cfg fix */ | |
| 1388 e02 = split_block (bb0, cond_stmt); | |
| 1389 bb2 = e02->dest; | |
| 1390 | |
| 111 | 1391 if (info->default_case_nonstandard) |
| 1392 { | |
| 1393 bb1 = bb2; | |
| 1394 bb2 = info->default_bb; | |
| 1395 e01 = e02; | |
| 1396 e01->flags = EDGE_TRUE_VALUE; | |
| 1397 e02 = make_edge (bb0, bb2, EDGE_FALSE_VALUE); | |
| 1398 edge e_default = find_edge (bb1, bb2); | |
| 1399 for (gphi_iterator gsi = gsi_start_phis (bb2); | |
| 1400 !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 1401 { | |
| 1402 gphi *phi = gsi.phi (); | |
| 1403 tree arg = PHI_ARG_DEF_FROM_EDGE (phi, e_default); | |
| 1404 add_phi_arg (phi, arg, e02, | |
| 1405 gimple_phi_arg_location_from_edge (phi, e_default)); | |
| 1406 } | |
| 1407 /* Partially fix the dominator tree, if it is available. */ | |
| 1408 if (dom_info_available_p (CDI_DOMINATORS)) | |
| 1409 redirect_immediate_dominators (CDI_DOMINATORS, bb1, bb0); | |
| 1410 } | |
| 1411 else | |
| 1412 { | |
| 1413 e21 = split_block (bb2, last_assign); | |
| 1414 bb1 = e21->dest; | |
| 1415 remove_edge (e21); | |
| 1416 } | |
| 1417 | |
| 1418 e1d = split_block (bb1, info->arr_ref_last); | |
| 0 | 1419 bbd = e1d->dest; |
| 1420 remove_edge (e1d); | |
| 1421 | |
| 1422 /* flags and profiles of the edge for in-range values */ | |
| 111 | 1423 if (!info->default_case_nonstandard) |
| 1424 e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE); | |
| 1425 e01->probability = info->default_prob.invert (); | |
| 0 | 1426 |
| 1427 /* flags and profiles of the edge taking care of out-of-range values */ | |
| 1428 e02->flags &= ~EDGE_FALLTHRU; | |
| 1429 e02->flags |= EDGE_FALSE_VALUE; | |
| 111 | 1430 e02->probability = info->default_prob; |
| 1431 | |
| 1432 bbf = info->final_bb; | |
| 0 | 1433 |
| 1434 e1f = make_edge (bb1, bbf, EDGE_FALLTHRU); | |
| 111 | 1435 e1f->probability = profile_probability::always (); |
| 1436 | |
| 1437 if (info->default_case_nonstandard) | |
| 1438 e2f = NULL; | |
| 1439 else | |
| 1440 { | |
| 1441 e2f = make_edge (bb2, bbf, EDGE_FALLTHRU); | |
| 1442 e2f->probability = profile_probability::always (); | |
| 1443 } | |
| 0 | 1444 |
| 1445 /* frequencies of the new BBs */ | |
| 1446 bb1->frequency = EDGE_FREQUENCY (e01); | |
| 1447 bb2->frequency = EDGE_FREQUENCY (e02); | |
| 111 | 1448 if (!info->default_case_nonstandard) |
| 1449 bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f); | |
| 1450 | |
| 1451 /* Tidy blocks that have become unreachable. */ | |
| 1452 prune_bbs (bbd, info->final_bb, | |
| 1453 info->default_case_nonstandard ? info->default_bb : NULL); | |
| 1454 | |
| 1455 /* Fixup the PHI nodes in bbF. */ | |
| 1456 fix_phi_nodes (e1f, e2f, bbf, info); | |
| 1457 | |
| 1458 /* Fix the dominator tree, if it is available. */ | |
| 1459 if (dom_info_available_p (CDI_DOMINATORS)) | |
| 1460 { | |
| 1461 vec<basic_block> bbs_to_fix_dom; | |
| 1462 | |
| 1463 set_immediate_dominator (CDI_DOMINATORS, bb1, bb0); | |
| 1464 if (!info->default_case_nonstandard) | |
| 1465 set_immediate_dominator (CDI_DOMINATORS, bb2, bb0); | |
| 1466 if (! get_immediate_dominator (CDI_DOMINATORS, bbf)) | |
| 1467 /* If bbD was the immediate dominator ... */ | |
| 1468 set_immediate_dominator (CDI_DOMINATORS, bbf, bb0); | |
| 1469 | |
| 1470 bbs_to_fix_dom.create (3 + (bb2 != bbf)); | |
| 1471 bbs_to_fix_dom.quick_push (bb0); | |
| 1472 bbs_to_fix_dom.quick_push (bb1); | |
| 1473 if (bb2 != bbf) | |
| 1474 bbs_to_fix_dom.quick_push (bb2); | |
| 1475 bbs_to_fix_dom.quick_push (bbf); | |
| 1476 | |
| 1477 iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
| 1478 bbs_to_fix_dom.release (); | |
| 1479 } | |
| 0 | 1480 } |
| 1481 | |
| 1482 /* The following function is invoked on every switch statement (the current one | |
| 1483 is given in SWTCH) and runs the individual phases of switch conversion on it | |
| 111 | 1484 one after another until one fails or the conversion is completed. |
| 1485 Returns NULL on success, or a pointer to a string with the reason why the | |
| 1486 conversion failed. */ | |
| 1487 | |
| 1488 static const char * | |
| 1489 process_switch (gswitch *swtch) | |
| 0 | 1490 { |
| 111 | 1491 struct switch_conv_info info; |
| 1492 | |
| 1493 /* Group case labels so that we get the right results from the heuristics | |
| 1494 that decide on the code generation approach for this switch. */ | |
| 1495 group_case_labels_stmt (swtch); | |
| 1496 | |
| 1497 /* If this switch is now a degenerate case with only a default label, | |
| 1498 there is nothing left for us to do. */ | |
| 1499 if (gimple_switch_num_labels (swtch) < 2) | |
| 1500 return "switch is a degenerate case"; | |
| 1501 | |
| 1502 collect_switch_conv_info (swtch, &info); | |
| 1503 | |
| 1504 /* No error markers should reach here (they should be filtered out | |
| 1505 during gimplification). */ | |
| 1506 gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node); | |
| 1507 | |
| 1508 /* A switch on a constant should have been optimized in tree-cfg-cleanup. */ | |
| 1509 gcc_checking_assert (! TREE_CONSTANT (info.index_expr)); | |
| 1510 | |
| 1511 if (info.uniq <= MAX_CASE_BIT_TESTS) | |
| 0 | 1512 { |
| 111 | 1513 if (expand_switch_using_bit_tests_p (info.range_size, |
| 1514 info.uniq, info.count, | |
| 1515 optimize_bb_for_speed_p | |
| 1516 (gimple_bb (swtch)))) | |
| 1517 { | |
| 1518 if (dump_file) | |
| 1519 fputs (" expanding as bit test is preferable\n", dump_file); | |
| 1520 emit_case_bit_tests (swtch, info.index_expr, info.range_min, | |
| 1521 info.range_size, info.range_max); | |
| 1522 loops_state_set (LOOPS_NEED_FIXUP); | |
| 1523 return NULL; | |
| 1524 } | |
| 1525 | |
| 1526 if (info.uniq <= 2) | |
| 1527 /* This will be expanded as a decision tree in stmt.c:expand_case. */ | |
| 1528 return " expanding as jumps is preferable"; | |
| 0 | 1529 } |
| 1530 | |
| 111 | 1531 /* If there is no common successor, we cannot do the transformation. */ |
| 1532 if (! info.final_bb) | |
| 1533 return "no common successor to all case label target blocks found"; | |
| 0 | 1534 |
| 1535 /* Check the case label values are within reasonable range: */ | |
| 111 | 1536 if (!check_range (&info)) |
| 1537 { | |
| 1538 gcc_assert (info.reason); | |
| 1539 return info.reason; | |
| 1540 } | |
| 0 | 1541 |
| 1542 /* For all the cases, see whether they are empty, the assignments they | |
| 1543 represent constant and so on... */ | |
| 111 | 1544 if (! check_all_empty_except_final (&info)) |
|
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|
1545 { |
| 111 | 1546 gcc_assert (info.reason); |
| 1547 return info.reason; | |
|
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|
1548 } |
| 111 | 1549 if (!check_final_bb (swtch, &info)) |
| 1550 { | |
| 1551 gcc_assert (info.reason); | |
| 1552 return info.reason; | |
| 1553 } | |
| 0 | 1554 |
| 1555 /* At this point all checks have passed and we can proceed with the | |
| 1556 transformation. */ | |
| 1557 | |
| 111 | 1558 create_temp_arrays (&info); |
| 1559 gather_default_values (info.default_case_nonstandard | |
| 1560 ? gimple_switch_label (swtch, 1) | |
| 1561 : gimple_switch_default_label (swtch), &info); | |
| 1562 build_constructors (swtch, &info); | |
| 1563 | |
| 1564 build_arrays (swtch, &info); /* Build the static arrays and assignments. */ | |
| 1565 gen_inbound_check (swtch, &info); /* Build the bounds check. */ | |
| 0 | 1566 |
| 1567 /* Cleanup: */ | |
| 111 | 1568 free_temp_arrays (&info); |
| 1569 return NULL; | |
| 0 | 1570 } |
| 1571 | |
| 1572 /* The main function of the pass scans statements for switches and invokes | |
| 1573 process_switch on them. */ | |
| 1574 | |
| 111 | 1575 namespace { |
| 1576 | |
| 1577 const pass_data pass_data_convert_switch = | |
| 1578 { | |
| 1579 GIMPLE_PASS, /* type */ | |
| 1580 "switchconv", /* name */ | |
| 1581 OPTGROUP_NONE, /* optinfo_flags */ | |
| 1582 TV_TREE_SWITCH_CONVERSION, /* tv_id */ | |
| 1583 ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
| 1584 0, /* properties_provided */ | |
| 1585 0, /* properties_destroyed */ | |
| 1586 0, /* todo_flags_start */ | |
| 1587 TODO_update_ssa, /* todo_flags_finish */ | |
| 1588 }; | |
| 1589 | |
| 1590 class pass_convert_switch : public gimple_opt_pass | |
| 1591 { | |
| 1592 public: | |
| 1593 pass_convert_switch (gcc::context *ctxt) | |
| 1594 : gimple_opt_pass (pass_data_convert_switch, ctxt) | |
| 1595 {} | |
| 1596 | |
| 1597 /* opt_pass methods: */ | |
| 1598 virtual bool gate (function *) { return flag_tree_switch_conversion != 0; } | |
| 1599 virtual unsigned int execute (function *); | |
| 1600 | |
| 1601 }; // class pass_convert_switch | |
| 1602 | |
| 1603 unsigned int | |
| 1604 pass_convert_switch::execute (function *fun) | |
| 0 | 1605 { |
| 1606 basic_block bb; | |
| 1607 | |
| 111 | 1608 FOR_EACH_BB_FN (bb, fun) |
| 0 | 1609 { |
| 111 | 1610 const char *failure_reason; |
| 1611 gimple *stmt = last_stmt (bb); | |
| 0 | 1612 if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) |
| 1613 { | |
| 1614 if (dump_file) | |
| 1615 { | |
| 1616 expanded_location loc = expand_location (gimple_location (stmt)); | |
| 1617 | |
| 1618 fprintf (dump_file, "beginning to process the following " | |
| 1619 "SWITCH statement (%s:%d) : ------- \n", | |
| 1620 loc.file, loc.line); | |
| 1621 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
|
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1622 putc ('\n', dump_file); |
| 0 | 1623 } |
| 1624 | |
| 111 | 1625 failure_reason = process_switch (as_a <gswitch *> (stmt)); |
| 1626 if (! failure_reason) | |
| 0 | 1627 { |
| 1628 if (dump_file) | |
| 1629 { | |
|
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1630 fputs ("Switch converted\n", dump_file); |
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1631 fputs ("--------------------------------\n", dump_file); |
| 0 | 1632 } |
| 111 | 1633 |
| 1634 /* Make no effort to update the post-dominator tree. It is actually not | |
| 1635 that hard for the transformations we have performed, but it is not | |
| 1636 supported by iterate_fix_dominators. */ | |
| 1637 free_dominance_info (CDI_POST_DOMINATORS); | |
| 0 | 1638 } |
| 1639 else | |
| 1640 { | |
| 1641 if (dump_file) | |
| 1642 { | |
|
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1643 fputs ("Bailing out - ", dump_file); |
| 111 | 1644 fputs (failure_reason, dump_file); |
| 1645 fputs ("\n--------------------------------\n", dump_file); | |
| 0 | 1646 } |
| 1647 } | |
| 1648 } | |
| 1649 } | |
| 1650 | |
| 1651 return 0; | |
| 1652 } | |
| 1653 | |
| 111 | 1654 } // anon namespace |
| 1655 | |
| 1656 gimple_opt_pass * | |
| 1657 make_pass_convert_switch (gcc::context *ctxt) | |
| 1658 { | |
| 1659 return new pass_convert_switch (ctxt); | |
| 1660 } | |
| 1661 | |
| 1662 struct case_node | |
| 1663 { | |
| 1664 case_node *left; /* Left son in binary tree. */ | |
| 1665 case_node *right; /* Right son in binary tree; | |
| 1666 also node chain. */ | |
| 1667 case_node *parent; /* Parent of node in binary tree. */ | |
| 1668 tree low; /* Lowest index value for this label. */ | |
| 1669 tree high; /* Highest index value for this label. */ | |
| 1670 basic_block case_bb; /* Label to jump to when node matches. */ | |
| 1671 tree case_label; /* Label to jump to when node matches. */ | |
| 1672 profile_probability prob; /* Probability of taking this case. */ | |
| 1673 profile_probability subtree_prob; /* Probability of reaching subtree | |
| 1674 rooted at this node. */ | |
| 1675 }; | |
| 1676 | |
| 1677 typedef case_node *case_node_ptr; | |
| 1678 | |
| 1679 static basic_block emit_case_nodes (basic_block, tree, case_node_ptr, | |
| 1680 basic_block, tree, profile_probability, | |
| 1681 tree, hash_map<tree, tree> *); | |
| 1682 static bool node_has_low_bound (case_node_ptr, tree); | |
| 1683 static bool node_has_high_bound (case_node_ptr, tree); | |
| 1684 static bool node_is_bounded (case_node_ptr, tree); | |
| 1685 | |
| 1686 /* Return the smallest number of different values for which it is best to use a | |
| 1687 jump-table instead of a tree of conditional branches. */ | |
| 1688 | |
| 1689 static unsigned int | |
| 1690 case_values_threshold (void) | |
| 1691 { | |
| 1692 unsigned int threshold = PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD); | |
| 1693 | |
| 1694 if (threshold == 0) | |
| 1695 threshold = targetm.case_values_threshold (); | |
| 1696 | |
| 1697 return threshold; | |
| 1698 } | |
| 1699 | |
| 1700 /* Reset the aux field of all outgoing edges of basic block BB. */ | |
| 1701 | |
| 1702 static inline void | |
| 1703 reset_out_edges_aux (basic_block bb) | |
| 1704 { | |
| 1705 edge e; | |
| 1706 edge_iterator ei; | |
| 1707 FOR_EACH_EDGE (e, ei, bb->succs) | |
| 1708 e->aux = (void *) 0; | |
| 1709 } | |
| 1710 | |
| 1711 /* Compute the number of case labels that correspond to each outgoing edge of | |
| 1712 STMT. Record this information in the aux field of the edge. */ | |
| 1713 | |
| 1714 static inline void | |
| 1715 compute_cases_per_edge (gswitch *stmt) | |
| 1716 { | |
| 1717 basic_block bb = gimple_bb (stmt); | |
| 1718 reset_out_edges_aux (bb); | |
| 1719 int ncases = gimple_switch_num_labels (stmt); | |
| 1720 for (int i = ncases - 1; i >= 1; --i) | |
| 1721 { | |
| 1722 tree elt = gimple_switch_label (stmt, i); | |
| 1723 tree lab = CASE_LABEL (elt); | |
| 1724 basic_block case_bb = label_to_block_fn (cfun, lab); | |
| 1725 edge case_edge = find_edge (bb, case_bb); | |
| 1726 case_edge->aux = (void *) ((intptr_t) (case_edge->aux) + 1); | |
| 1727 } | |
| 1728 } | |
| 1729 | |
| 1730 /* Do the insertion of a case label into case_list. The labels are | |
| 1731 fed to us in descending order from the sorted vector of case labels used | |
| 1732 in the tree part of the middle end. So the list we construct is | |
| 1733 sorted in ascending order. | |
| 1734 | |
| 1735 LABEL is the case label to be inserted. LOW and HIGH are the bounds | |
| 1736 against which the index is compared to jump to LABEL and PROB is the | |
| 1737 estimated probability LABEL is reached from the switch statement. */ | |
| 1738 | |
| 1739 static case_node * | |
| 1740 add_case_node (case_node *head, tree low, tree high, basic_block case_bb, | |
| 1741 tree case_label, profile_probability prob, | |
| 1742 object_allocator<case_node> &case_node_pool) | |
| 1743 { | |
| 1744 case_node *r; | |
| 1745 | |
| 1746 gcc_checking_assert (low); | |
| 1747 gcc_checking_assert (high && (TREE_TYPE (low) == TREE_TYPE (high))); | |
| 1748 | |
| 1749 /* Add this label to the chain. */ | |
| 1750 r = case_node_pool.allocate (); | |
| 1751 r->low = low; | |
| 1752 r->high = high; | |
| 1753 r->case_bb = case_bb; | |
| 1754 r->case_label = case_label; | |
| 1755 r->parent = r->left = NULL; | |
| 1756 r->prob = prob; | |
| 1757 r->subtree_prob = prob; | |
| 1758 r->right = head; | |
| 1759 return r; | |
| 1760 } | |
| 1761 | |
| 1762 /* Dump ROOT, a list or tree of case nodes, to file. */ | |
| 1763 | |
| 1764 static void | |
| 1765 dump_case_nodes (FILE *f, case_node *root, int indent_step, int indent_level) | |
| 1766 { | |
| 1767 if (root == 0) | |
| 1768 return; | |
| 1769 indent_level++; | |
| 1770 | |
| 1771 dump_case_nodes (f, root->left, indent_step, indent_level); | |
| 1772 | |
| 1773 fputs (";; ", f); | |
| 1774 fprintf (f, "%*s", indent_step * indent_level, ""); | |
| 1775 print_dec (wi::to_wide (root->low), f, TYPE_SIGN (TREE_TYPE (root->low))); | |
| 1776 if (!tree_int_cst_equal (root->low, root->high)) | |
| 1777 { | |
| 1778 fprintf (f, " ... "); | |
| 1779 print_dec (wi::to_wide (root->high), f, | |
| 1780 TYPE_SIGN (TREE_TYPE (root->high))); | |
| 1781 } | |
| 1782 fputs ("\n", f); | |
| 1783 | |
| 1784 dump_case_nodes (f, root->right, indent_step, indent_level); | |
| 1785 } | |
| 1786 | |
| 1787 /* Take an ordered list of case nodes | |
| 1788 and transform them into a near optimal binary tree, | |
| 1789 on the assumption that any target code selection value is as | |
| 1790 likely as any other. | |
| 1791 | |
| 1792 The transformation is performed by splitting the ordered | |
| 1793 list into two equal sections plus a pivot. The parts are | |
| 1794 then attached to the pivot as left and right branches. Each | |
| 1795 branch is then transformed recursively. */ | |
| 1796 | |
| 1797 static void | |
| 1798 balance_case_nodes (case_node_ptr *head, case_node_ptr parent) | |
| 1799 { | |
| 1800 case_node_ptr np; | |
| 1801 | |
| 1802 np = *head; | |
| 1803 if (np) | |
| 1804 { | |
| 1805 int i = 0; | |
| 1806 int ranges = 0; | |
| 1807 case_node_ptr *npp; | |
| 1808 case_node_ptr left; | |
| 1809 | |
| 1810 /* Count the number of entries on branch. Also count the ranges. */ | |
| 1811 | |
| 1812 while (np) | |
| 1813 { | |
| 1814 if (!tree_int_cst_equal (np->low, np->high)) | |
| 1815 ranges++; | |
| 1816 | |
| 1817 i++; | |
| 1818 np = np->right; | |
| 1819 } | |
| 1820 | |
| 1821 if (i > 2) | |
| 1822 { | |
| 1823 /* Split this list if it is long enough for that to help. */ | |
| 1824 npp = head; | |
| 1825 left = *npp; | |
| 1826 | |
| 1827 /* If there are just three nodes, split at the middle one. */ | |
| 1828 if (i == 3) | |
| 1829 npp = &(*npp)->right; | |
| 1830 else | |
| 1831 { | |
| 1832 /* Find the place in the list that bisects the list's total cost, | |
| 1833 where ranges count as 2. | |
| 1834 Here I gets half the total cost. */ | |
| 1835 i = (i + ranges + 1) / 2; | |
| 1836 while (1) | |
| 1837 { | |
| 1838 /* Skip nodes while their cost does not reach that amount. */ | |
| 1839 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) | |
| 1840 i--; | |
| 1841 i--; | |
| 1842 if (i <= 0) | |
| 1843 break; | |
| 1844 npp = &(*npp)->right; | |
| 1845 } | |
| 1846 } | |
| 1847 *head = np = *npp; | |
| 1848 *npp = 0; | |
| 1849 np->parent = parent; | |
| 1850 np->left = left; | |
| 1851 | |
| 1852 /* Optimize each of the two split parts. */ | |
| 1853 balance_case_nodes (&np->left, np); | |
| 1854 balance_case_nodes (&np->right, np); | |
| 1855 np->subtree_prob = np->prob; | |
| 1856 np->subtree_prob += np->left->subtree_prob; | |
| 1857 np->subtree_prob += np->right->subtree_prob; | |
| 1858 } | |
| 1859 else | |
| 1860 { | |
| 1861 /* Else leave this branch as one level, | |
| 1862 but fill in `parent' fields. */ | |
| 1863 np = *head; | |
| 1864 np->parent = parent; | |
| 1865 np->subtree_prob = np->prob; | |
| 1866 for (; np->right; np = np->right) | |
| 1867 { | |
| 1868 np->right->parent = np; | |
| 1869 (*head)->subtree_prob += np->right->subtree_prob; | |
| 1870 } | |
| 1871 } | |
| 1872 } | |
| 1873 } | |
| 1874 | |
| 1875 /* Return true if a switch should be expanded as a decision tree. | |
| 1876 RANGE is the difference between highest and lowest case. | |
| 1877 UNIQ is number of unique case node targets, not counting the default case. | |
| 1878 COUNT is the number of comparisons needed, not counting the default case. */ | |
| 1879 | |
| 1880 static bool | |
| 1881 expand_switch_as_decision_tree_p (tree range, | |
| 1882 unsigned int uniq ATTRIBUTE_UNUSED, | |
| 1883 unsigned int count) | |
| 1884 { | |
| 1885 int max_ratio; | |
| 1886 | |
| 1887 /* If neither casesi or tablejump is available, or flag_jump_tables | |
| 1888 over-ruled us, we really have no choice. */ | |
| 1889 if (!targetm.have_casesi () && !targetm.have_tablejump ()) | |
| 1890 return true; | |
| 1891 if (!flag_jump_tables) | |
| 1892 return true; | |
| 1893 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT | |
| 1894 if (flag_pic) | |
| 1895 return true; | |
| 1896 #endif | |
| 1897 | |
| 1898 /* If the switch is relatively small such that the cost of one | |
| 1899 indirect jump on the target are higher than the cost of a | |
| 1900 decision tree, go with the decision tree. | |
| 1901 | |
| 1902 If range of values is much bigger than number of values, | |
| 1903 or if it is too large to represent in a HOST_WIDE_INT, | |
| 1904 make a sequence of conditional branches instead of a dispatch. | |
| 1905 | |
| 1906 The definition of "much bigger" depends on whether we are | |
| 1907 optimizing for size or for speed. If the former, the maximum | |
| 1908 ratio range/count = 3, because this was found to be the optimal | |
| 1909 ratio for size on i686-pc-linux-gnu, see PR11823. The ratio | |
| 1910 10 is much older, and was probably selected after an extensive | |
| 1911 benchmarking investigation on numerous platforms. Or maybe it | |
| 1912 just made sense to someone at some point in the history of GCC, | |
| 1913 who knows... */ | |
| 1914 max_ratio = optimize_insn_for_size_p () ? 3 : 10; | |
| 1915 if (count < case_values_threshold () || !tree_fits_uhwi_p (range) | |
| 1916 || compare_tree_int (range, max_ratio * count) > 0) | |
| 1917 return true; | |
| 1918 | |
| 1919 return false; | |
| 1920 } | |
| 1921 | |
| 1922 static void | |
| 1923 fix_phi_operands_for_edge (edge e, hash_map<tree, tree> *phi_mapping) | |
| 1924 { | |
| 1925 basic_block bb = e->dest; | |
| 1926 gphi_iterator gsi; | |
| 1927 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 1928 { | |
| 1929 gphi *phi = gsi.phi (); | |
| 1930 | |
| 1931 tree *definition = phi_mapping->get (gimple_phi_result (phi)); | |
| 1932 if (definition) | |
| 1933 add_phi_arg (phi, *definition, e, UNKNOWN_LOCATION); | |
| 1934 } | |
| 1935 } | |
| 1936 | |
| 1937 | |
| 1938 /* Add an unconditional jump to CASE_BB that happens in basic block BB. */ | |
| 1939 | |
| 1940 static void | |
| 1941 emit_jump (basic_block bb, basic_block case_bb, | |
| 1942 hash_map<tree, tree> *phi_mapping) | |
| 1943 { | |
| 1944 edge e = single_succ_edge (bb); | |
| 1945 redirect_edge_succ (e, case_bb); | |
| 1946 fix_phi_operands_for_edge (e, phi_mapping); | |
| 1947 } | |
| 1948 | |
| 1949 /* Generate a decision tree, switching on INDEX_EXPR and jumping to | |
| 1950 one of the labels in CASE_LIST or to the DEFAULT_LABEL. | |
| 1951 DEFAULT_PROB is the estimated probability that it jumps to | |
| 1952 DEFAULT_LABEL. | |
| 1953 | |
| 1954 We generate a binary decision tree to select the appropriate target | |
| 1955 code. */ | |
| 1956 | |
| 1957 static void | |
| 1958 emit_case_decision_tree (gswitch *s, tree index_expr, tree index_type, | |
| 1959 case_node_ptr case_list, basic_block default_bb, | |
| 1960 tree default_label, profile_probability default_prob, | |
| 1961 hash_map<tree, tree> *phi_mapping) | |
| 1962 { | |
| 1963 balance_case_nodes (&case_list, NULL); | |
| 1964 | |
| 1965 if (dump_file) | |
| 1966 dump_function_to_file (current_function_decl, dump_file, dump_flags); | |
| 1967 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1968 { | |
| 1969 int indent_step = ceil_log2 (TYPE_PRECISION (index_type)) + 2; | |
| 1970 fprintf (dump_file, ";; Expanding GIMPLE switch as decision tree:\n"); | |
| 1971 dump_case_nodes (dump_file, case_list, indent_step, 0); | |
| 1972 } | |
| 1973 | |
| 1974 basic_block bb = gimple_bb (s); | |
| 1975 gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
| 1976 edge e; | |
| 1977 if (gsi_end_p (gsi)) | |
| 1978 e = split_block_after_labels (bb); | |
| 1979 else | |
| 1980 { | |
| 1981 gsi_prev (&gsi); | |
| 1982 e = split_block (bb, gsi_stmt (gsi)); | |
| 1983 } | |
| 1984 bb = split_edge (e); | |
| 1985 | |
| 1986 bb = emit_case_nodes (bb, index_expr, case_list, default_bb, default_label, | |
| 1987 default_prob, index_type, phi_mapping); | |
| 1988 | |
| 1989 if (bb) | |
| 1990 emit_jump (bb, default_bb, phi_mapping); | |
| 1991 | |
| 1992 /* Remove all edges and do just an edge that will reach default_bb. */ | |
| 1993 gsi = gsi_last_bb (gimple_bb (s)); | |
| 1994 gsi_remove (&gsi, true); | |
| 1995 } | |
| 1996 | |
| 1997 static void | |
| 1998 record_phi_operand_mapping (const vec<basic_block> bbs, basic_block switch_bb, | |
| 1999 hash_map <tree, tree> *map) | |
| 2000 { | |
| 2001 /* Record all PHI nodes that have to be fixed after conversion. */ | |
| 2002 for (unsigned i = 0; i < bbs.length (); i++) | |
| 2003 { | |
| 2004 basic_block bb = bbs[i]; | |
| 2005 | |
| 2006 gphi_iterator gsi; | |
| 2007 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 2008 { | |
| 2009 gphi *phi = gsi.phi (); | |
| 2010 | |
| 2011 for (unsigned i = 0; i < gimple_phi_num_args (phi); i++) | |
| 2012 { | |
| 2013 basic_block phi_src_bb = gimple_phi_arg_edge (phi, i)->src; | |
| 2014 if (phi_src_bb == switch_bb) | |
| 2015 { | |
| 2016 tree def = gimple_phi_arg_def (phi, i); | |
| 2017 tree result = gimple_phi_result (phi); | |
| 2018 map->put (result, def); | |
| 2019 break; | |
| 2020 } | |
| 2021 } | |
| 2022 } | |
| 2023 } | |
| 2024 } | |
| 2025 | |
| 2026 /* Attempt to expand gimple switch STMT to a decision tree. */ | |
| 0 | 2027 |
| 2028 static bool | |
| 111 | 2029 try_switch_expansion (gswitch *stmt) |
| 2030 { | |
| 2031 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE; | |
| 2032 basic_block default_bb; | |
| 2033 unsigned int count, uniq; | |
| 2034 int i; | |
| 2035 int ncases = gimple_switch_num_labels (stmt); | |
| 2036 tree index_expr = gimple_switch_index (stmt); | |
| 2037 tree index_type = TREE_TYPE (index_expr); | |
| 2038 tree elt; | |
| 2039 basic_block bb = gimple_bb (stmt); | |
| 2040 | |
| 2041 hash_map<tree, tree> phi_mapping; | |
| 2042 auto_vec<basic_block> case_bbs; | |
| 2043 | |
| 2044 /* A list of case labels; it is first built as a list and it may then | |
| 2045 be rearranged into a nearly balanced binary tree. */ | |
| 2046 case_node *case_list = 0; | |
| 2047 | |
| 2048 /* A pool for case nodes. */ | |
| 2049 object_allocator<case_node> case_node_pool ("struct case_node pool"); | |
| 2050 | |
| 2051 /* cleanup_tree_cfg removes all SWITCH_EXPR with their index | |
| 2052 expressions being INTEGER_CST. */ | |
| 2053 gcc_assert (TREE_CODE (index_expr) != INTEGER_CST); | |
| 2054 | |
| 2055 if (ncases == 1) | |
| 2056 return false; | |
| 2057 | |
| 2058 /* Find the default case target label. */ | |
| 2059 tree default_label = CASE_LABEL (gimple_switch_default_label (stmt)); | |
| 2060 default_bb = label_to_block_fn (cfun, default_label); | |
| 2061 edge default_edge = find_edge (bb, default_bb); | |
| 2062 profile_probability default_prob = default_edge->probability; | |
| 2063 case_bbs.safe_push (default_bb); | |
| 2064 | |
| 2065 /* Get upper and lower bounds of case values. */ | |
| 2066 elt = gimple_switch_label (stmt, 1); | |
| 2067 minval = fold_convert (index_type, CASE_LOW (elt)); | |
| 2068 elt = gimple_switch_label (stmt, ncases - 1); | |
| 2069 if (CASE_HIGH (elt)) | |
| 2070 maxval = fold_convert (index_type, CASE_HIGH (elt)); | |
| 2071 else | |
| 2072 maxval = fold_convert (index_type, CASE_LOW (elt)); | |
| 2073 | |
| 2074 /* Compute span of values. */ | |
| 2075 range = fold_build2 (MINUS_EXPR, index_type, maxval, minval); | |
| 2076 | |
| 2077 /* Listify the labels queue and gather some numbers to decide | |
| 2078 how to expand this switch. */ | |
| 2079 uniq = 0; | |
| 2080 count = 0; | |
| 2081 hash_set<tree> seen_labels; | |
| 2082 compute_cases_per_edge (stmt); | |
| 2083 | |
| 2084 for (i = ncases - 1; i >= 1; --i) | |
| 2085 { | |
| 2086 elt = gimple_switch_label (stmt, i); | |
| 2087 tree low = CASE_LOW (elt); | |
| 2088 gcc_assert (low); | |
| 2089 tree high = CASE_HIGH (elt); | |
| 2090 gcc_assert (!high || tree_int_cst_lt (low, high)); | |
| 2091 tree lab = CASE_LABEL (elt); | |
| 2092 | |
| 2093 /* Count the elements. | |
| 2094 A range counts double, since it requires two compares. */ | |
| 2095 count++; | |
| 2096 if (high) | |
| 2097 count++; | |
| 2098 | |
| 2099 /* If we have not seen this label yet, then increase the | |
| 2100 number of unique case node targets seen. */ | |
| 2101 if (!seen_labels.add (lab)) | |
| 2102 uniq++; | |
| 2103 | |
| 2104 /* The bounds on the case range, LOW and HIGH, have to be converted | |
| 2105 to case's index type TYPE. Note that the original type of the | |
| 2106 case index in the source code is usually "lost" during | |
| 2107 gimplification due to type promotion, but the case labels retain the | |
| 2108 original type. Make sure to drop overflow flags. */ | |
| 2109 low = fold_convert (index_type, low); | |
| 2110 if (TREE_OVERFLOW (low)) | |
| 2111 low = wide_int_to_tree (index_type, wi::to_wide (low)); | |
| 2112 | |
| 2113 /* The canonical from of a case label in GIMPLE is that a simple case | |
| 2114 has an empty CASE_HIGH. For the casesi and tablejump expanders, | |
| 2115 the back ends want simple cases to have high == low. */ | |
| 2116 if (!high) | |
| 2117 high = low; | |
| 2118 high = fold_convert (index_type, high); | |
| 2119 if (TREE_OVERFLOW (high)) | |
| 2120 high = wide_int_to_tree (index_type, wi::to_wide (high)); | |
| 2121 | |
| 2122 basic_block case_bb = label_to_block_fn (cfun, lab); | |
| 2123 edge case_edge = find_edge (bb, case_bb); | |
| 2124 case_list = add_case_node ( | |
| 2125 case_list, low, high, case_bb, lab, | |
| 2126 case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux)), | |
| 2127 case_node_pool); | |
| 2128 | |
| 2129 case_bbs.safe_push (case_bb); | |
| 2130 } | |
| 2131 reset_out_edges_aux (bb); | |
| 2132 record_phi_operand_mapping (case_bbs, bb, &phi_mapping); | |
| 2133 | |
| 2134 /* cleanup_tree_cfg removes all SWITCH_EXPR with a single | |
| 2135 destination, such as one with a default case only. | |
| 2136 It also removes cases that are out of range for the switch | |
| 2137 type, so we should never get a zero here. */ | |
| 2138 gcc_assert (count > 0); | |
| 2139 | |
| 2140 /* Decide how to expand this switch. | |
| 2141 The two options at this point are a dispatch table (casesi or | |
| 2142 tablejump) or a decision tree. */ | |
| 2143 | |
| 2144 if (expand_switch_as_decision_tree_p (range, uniq, count)) | |
| 2145 { | |
| 2146 emit_case_decision_tree (stmt, index_expr, index_type, case_list, | |
| 2147 default_bb, default_label, default_prob, | |
| 2148 &phi_mapping); | |
| 2149 return true; | |
| 2150 } | |
| 2151 | |
| 2152 return false; | |
| 2153 } | |
| 2154 | |
| 2155 /* The main function of the pass scans statements for switches and invokes | |
| 2156 process_switch on them. */ | |
| 2157 | |
| 2158 namespace { | |
| 2159 | |
| 2160 const pass_data pass_data_lower_switch = | |
| 2161 { | |
| 2162 GIMPLE_PASS, /* type */ | |
| 2163 "switchlower", /* name */ | |
| 2164 OPTGROUP_NONE, /* optinfo_flags */ | |
| 2165 TV_TREE_SWITCH_LOWERING, /* tv_id */ | |
| 2166 ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
| 2167 0, /* properties_provided */ | |
| 2168 0, /* properties_destroyed */ | |
| 2169 0, /* todo_flags_start */ | |
| 2170 TODO_update_ssa | TODO_cleanup_cfg, /* todo_flags_finish */ | |
| 2171 }; | |
| 2172 | |
| 2173 class pass_lower_switch : public gimple_opt_pass | |
| 0 | 2174 { |
| 111 | 2175 public: |
| 2176 pass_lower_switch (gcc::context *ctxt) | |
| 2177 : gimple_opt_pass (pass_data_lower_switch, ctxt) | |
| 2178 {} | |
| 2179 | |
| 2180 /* opt_pass methods: */ | |
| 2181 virtual bool gate (function *) { return true; } | |
| 2182 virtual unsigned int execute (function *); | |
| 2183 | |
| 2184 }; // class pass_lower_switch | |
| 2185 | |
| 2186 unsigned int | |
| 2187 pass_lower_switch::execute (function *fun) | |
| 2188 { | |
| 2189 basic_block bb; | |
| 2190 bool expanded = false; | |
| 2191 | |
| 2192 FOR_EACH_BB_FN (bb, fun) | |
| 2193 { | |
| 2194 gimple *stmt = last_stmt (bb); | |
| 2195 if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) | |
| 2196 { | |
| 2197 if (dump_file) | |
| 2198 { | |
| 2199 expanded_location loc = expand_location (gimple_location (stmt)); | |
| 2200 | |
| 2201 fprintf (dump_file, "beginning to process the following " | |
| 2202 "SWITCH statement (%s:%d) : ------- \n", | |
| 2203 loc.file, loc.line); | |
| 2204 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 2205 putc ('\n', dump_file); | |
| 2206 } | |
| 2207 | |
| 2208 expanded |= try_switch_expansion (as_a<gswitch *> (stmt)); | |
| 2209 } | |
| 2210 } | |
| 2211 | |
| 2212 if (expanded) | |
| 2213 { | |
| 2214 free_dominance_info (CDI_DOMINATORS); | |
| 2215 free_dominance_info (CDI_POST_DOMINATORS); | |
| 2216 mark_virtual_operands_for_renaming (cfun); | |
| 2217 } | |
| 2218 | |
| 2219 return 0; | |
| 2220 } | |
| 2221 | |
| 2222 } // anon namespace | |
| 2223 | |
| 2224 gimple_opt_pass * | |
| 2225 make_pass_lower_switch (gcc::context *ctxt) | |
| 2226 { | |
| 2227 return new pass_lower_switch (ctxt); | |
| 2228 } | |
| 2229 | |
| 2230 /* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. | |
| 2231 PROB is the probability of jumping to LABEL. */ | |
| 2232 static basic_block | |
| 2233 do_jump_if_equal (basic_block bb, tree op0, tree op1, basic_block label_bb, | |
| 2234 profile_probability prob, hash_map<tree, tree> *phi_mapping) | |
| 2235 { | |
| 2236 gcond *cond = gimple_build_cond (EQ_EXPR, op0, op1, NULL_TREE, NULL_TREE); | |
| 2237 gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
| 2238 gsi_insert_before (&gsi, cond, GSI_SAME_STMT); | |
| 2239 | |
| 2240 gcc_assert (single_succ_p (bb)); | |
| 2241 | |
| 2242 /* Make a new basic block where false branch will take place. */ | |
| 2243 edge false_edge = split_block (bb, cond); | |
| 2244 false_edge->flags = EDGE_FALSE_VALUE; | |
| 2245 false_edge->probability = prob.invert (); | |
| 2246 | |
| 2247 edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); | |
| 2248 fix_phi_operands_for_edge (true_edge, phi_mapping); | |
| 2249 true_edge->probability = prob; | |
| 2250 | |
| 2251 return false_edge->dest; | |
| 0 | 2252 } |
| 2253 | |
| 111 | 2254 /* Generate code to compare X with Y so that the condition codes are |
| 2255 set and to jump to LABEL if the condition is true. If X is a | |
| 2256 constant and Y is not a constant, then the comparison is swapped to | |
| 2257 ensure that the comparison RTL has the canonical form. | |
| 2258 | |
| 2259 UNSIGNEDP nonzero says that X and Y are unsigned; this matters if they | |
| 2260 need to be widened. UNSIGNEDP is also used to select the proper | |
| 2261 branch condition code. | |
| 2262 | |
| 2263 If X and Y have mode BLKmode, then SIZE specifies the size of both X and Y. | |
| 2264 | |
| 2265 MODE is the mode of the inputs (in case they are const_int). | |
| 2266 | |
| 2267 COMPARISON is the rtl operator to compare with (EQ, NE, GT, etc.). | |
| 2268 It will be potentially converted into an unsigned variant based on | |
| 2269 UNSIGNEDP to select a proper jump instruction. | |
| 2270 | |
| 2271 PROB is the probability of jumping to LABEL. */ | |
| 2272 | |
| 2273 static basic_block | |
| 2274 emit_cmp_and_jump_insns (basic_block bb, tree op0, tree op1, | |
| 2275 tree_code comparison, basic_block label_bb, | |
| 2276 profile_probability prob, | |
| 2277 hash_map<tree, tree> *phi_mapping) | |
| 2278 { | |
| 2279 gcond *cond = gimple_build_cond (comparison, op0, op1, NULL_TREE, NULL_TREE); | |
| 2280 gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
| 2281 gsi_insert_after (&gsi, cond, GSI_NEW_STMT); | |
| 2282 | |
| 2283 gcc_assert (single_succ_p (bb)); | |
| 2284 | |
| 2285 /* Make a new basic block where false branch will take place. */ | |
| 2286 edge false_edge = split_block (bb, cond); | |
| 2287 false_edge->flags = EDGE_FALSE_VALUE; | |
| 2288 false_edge->probability = prob.invert (); | |
| 2289 | |
| 2290 edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); | |
| 2291 fix_phi_operands_for_edge (true_edge, phi_mapping); | |
| 2292 true_edge->probability = prob; | |
| 2293 | |
| 2294 return false_edge->dest; | |
| 2295 } | |
| 2296 | |
| 2297 /* Computes the conditional probability of jumping to a target if the branch | |
| 2298 instruction is executed. | |
| 2299 TARGET_PROB is the estimated probability of jumping to a target relative | |
| 2300 to some basic block BB. | |
| 2301 BASE_PROB is the probability of reaching the branch instruction relative | |
| 2302 to the same basic block BB. */ | |
| 2303 | |
| 2304 static inline profile_probability | |
| 2305 conditional_probability (profile_probability target_prob, | |
| 2306 profile_probability base_prob) | |
| 2307 { | |
| 2308 return target_prob / base_prob; | |
| 2309 } | |
| 2310 | |
| 2311 /* Emit step-by-step code to select a case for the value of INDEX. | |
| 2312 The thus generated decision tree follows the form of the | |
| 2313 case-node binary tree NODE, whose nodes represent test conditions. | |
| 2314 INDEX_TYPE is the type of the index of the switch. | |
| 2315 | |
| 2316 Care is taken to prune redundant tests from the decision tree | |
| 2317 by detecting any boundary conditions already checked by | |
| 2318 emitted rtx. (See node_has_high_bound, node_has_low_bound | |
| 2319 and node_is_bounded, above.) | |
| 2320 | |
| 2321 Where the test conditions can be shown to be redundant we emit | |
| 2322 an unconditional jump to the target code. As a further | |
| 2323 optimization, the subordinates of a tree node are examined to | |
| 2324 check for bounded nodes. In this case conditional and/or | |
| 2325 unconditional jumps as a result of the boundary check for the | |
| 2326 current node are arranged to target the subordinates associated | |
| 2327 code for out of bound conditions on the current node. | |
| 2328 | |
| 2329 We can assume that when control reaches the code generated here, | |
| 2330 the index value has already been compared with the parents | |
| 2331 of this node, and determined to be on the same side of each parent | |
| 2332 as this node is. Thus, if this node tests for the value 51, | |
| 2333 and a parent tested for 52, we don't need to consider | |
| 2334 the possibility of a value greater than 51. If another parent | |
| 2335 tests for the value 50, then this node need not test anything. */ | |
| 2336 | |
| 2337 static basic_block | |
| 2338 emit_case_nodes (basic_block bb, tree index, case_node_ptr node, | |
| 2339 basic_block default_bb, tree default_label, | |
| 2340 profile_probability default_prob, tree index_type, | |
| 2341 hash_map<tree, tree> *phi_mapping) | |
| 0 | 2342 { |
| 111 | 2343 /* If INDEX has an unsigned type, we must make unsigned branches. */ |
| 2344 profile_probability probability; | |
| 2345 profile_probability prob = node->prob, subtree_prob = node->subtree_prob; | |
| 2346 | |
| 2347 /* See if our parents have already tested everything for us. | |
| 2348 If they have, emit an unconditional jump for this node. */ | |
| 2349 if (node_is_bounded (node, index_type)) | |
| 2350 { | |
| 2351 emit_jump (bb, node->case_bb, phi_mapping); | |
| 2352 return NULL; | |
| 2353 } | |
| 2354 | |
| 2355 else if (tree_int_cst_equal (node->low, node->high)) | |
| 2356 { | |
| 2357 probability = conditional_probability (prob, subtree_prob + default_prob); | |
| 2358 /* Node is single valued. First see if the index expression matches | |
| 2359 this node and then check our children, if any. */ | |
| 2360 bb = do_jump_if_equal (bb, index, node->low, node->case_bb, probability, | |
| 2361 phi_mapping); | |
| 2362 /* Since this case is taken at this point, reduce its weight from | |
| 2363 subtree_weight. */ | |
| 2364 subtree_prob -= prob; | |
| 2365 if (node->right != 0 && node->left != 0) | |
| 2366 { | |
| 2367 /* This node has children on both sides. | |
| 2368 Dispatch to one side or the other | |
| 2369 by comparing the index value with this node's value. | |
| 2370 If one subtree is bounded, check that one first, | |
| 2371 so we can avoid real branches in the tree. */ | |
| 2372 | |
| 2373 if (node_is_bounded (node->right, index_type)) | |
| 2374 { | |
| 2375 probability | |
| 2376 = conditional_probability (node->right->prob, | |
| 2377 subtree_prob + default_prob); | |
| 2378 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2379 node->right->case_bb, probability, | |
| 2380 phi_mapping); | |
| 2381 bb = emit_case_nodes (bb, index, node->left, default_bb, | |
| 2382 default_label, default_prob, index_type, | |
| 2383 phi_mapping); | |
| 2384 } | |
| 2385 | |
| 2386 else if (node_is_bounded (node->left, index_type)) | |
| 2387 { | |
| 2388 probability | |
| 2389 = conditional_probability (node->left->prob, | |
| 2390 subtree_prob + default_prob); | |
| 2391 bb = emit_cmp_and_jump_insns (bb, index, node->high, LT_EXPR, | |
| 2392 node->left->case_bb, probability, | |
| 2393 phi_mapping); | |
| 2394 bb = emit_case_nodes (bb, index, node->right, default_bb, | |
| 2395 default_label, default_prob, index_type, | |
| 2396 phi_mapping); | |
| 2397 } | |
| 2398 | |
| 2399 /* If both children are single-valued cases with no | |
| 2400 children, finish up all the work. This way, we can save | |
| 2401 one ordered comparison. */ | |
| 2402 else if (tree_int_cst_equal (node->right->low, node->right->high) | |
| 2403 && node->right->left == 0 && node->right->right == 0 | |
| 2404 && tree_int_cst_equal (node->left->low, node->left->high) | |
| 2405 && node->left->left == 0 && node->left->right == 0) | |
| 2406 { | |
| 2407 /* Neither node is bounded. First distinguish the two sides; | |
| 2408 then emit the code for one side at a time. */ | |
| 2409 | |
| 2410 /* See if the value matches what the right hand side | |
| 2411 wants. */ | |
| 2412 probability | |
| 2413 = conditional_probability (node->right->prob, | |
| 2414 subtree_prob + default_prob); | |
| 2415 bb = do_jump_if_equal (bb, index, node->right->low, | |
| 2416 node->right->case_bb, probability, | |
| 2417 phi_mapping); | |
| 2418 | |
| 2419 /* See if the value matches what the left hand side | |
| 2420 wants. */ | |
| 2421 probability | |
| 2422 = conditional_probability (node->left->prob, | |
| 2423 subtree_prob + default_prob); | |
| 2424 bb = do_jump_if_equal (bb, index, node->left->low, | |
| 2425 node->left->case_bb, probability, | |
| 2426 phi_mapping); | |
| 2427 } | |
| 2428 | |
| 2429 else | |
| 2430 { | |
| 2431 /* Neither node is bounded. First distinguish the two sides; | |
| 2432 then emit the code for one side at a time. */ | |
| 2433 | |
| 2434 basic_block test_bb = split_edge (single_succ_edge (bb)); | |
| 2435 redirect_edge_succ (single_pred_edge (test_bb), | |
| 2436 single_succ_edge (bb)->dest); | |
| 2437 | |
| 2438 /* The default label could be reached either through the right | |
| 2439 subtree or the left subtree. Divide the probability | |
| 2440 equally. */ | |
| 2441 probability | |
| 2442 = conditional_probability (node->right->subtree_prob | |
| 2443 + default_prob.apply_scale (1, 2), | |
| 2444 subtree_prob + default_prob); | |
| 2445 /* See if the value is on the right. */ | |
| 2446 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2447 test_bb, probability, phi_mapping); | |
| 2448 default_prob = default_prob.apply_scale (1, 2); | |
| 2449 | |
| 2450 /* Value must be on the left. | |
| 2451 Handle the left-hand subtree. */ | |
| 2452 bb = emit_case_nodes (bb, index, node->left, default_bb, | |
| 2453 default_label, default_prob, index_type, | |
| 2454 phi_mapping); | |
| 2455 /* If left-hand subtree does nothing, | |
| 2456 go to default. */ | |
| 2457 | |
| 2458 if (bb && default_bb) | |
| 2459 emit_jump (bb, default_bb, phi_mapping); | |
| 2460 | |
| 2461 /* Code branches here for the right-hand subtree. */ | |
| 2462 bb = emit_case_nodes (test_bb, index, node->right, default_bb, | |
| 2463 default_label, default_prob, index_type, | |
| 2464 phi_mapping); | |
| 2465 } | |
| 2466 } | |
| 2467 else if (node->right != 0 && node->left == 0) | |
| 2468 { | |
| 2469 /* Here we have a right child but no left so we issue a conditional | |
| 2470 branch to default and process the right child. | |
| 2471 | |
| 2472 Omit the conditional branch to default if the right child | |
| 2473 does not have any children and is single valued; it would | |
| 2474 cost too much space to save so little time. */ | |
| 2475 | |
| 2476 if (node->right->right || node->right->left | |
| 2477 || !tree_int_cst_equal (node->right->low, node->right->high)) | |
| 2478 { | |
| 2479 if (!node_has_low_bound (node, index_type)) | |
| 2480 { | |
| 2481 probability | |
| 2482 = conditional_probability (default_prob.apply_scale (1, 2), | |
| 2483 subtree_prob + default_prob); | |
| 2484 bb = emit_cmp_and_jump_insns (bb, index, node->high, LT_EXPR, | |
| 2485 default_bb, probability, | |
| 2486 phi_mapping); | |
| 2487 default_prob = default_prob.apply_scale (1, 2); | |
| 2488 } | |
| 2489 | |
| 2490 bb = emit_case_nodes (bb, index, node->right, default_bb, | |
| 2491 default_label, default_prob, index_type, | |
| 2492 phi_mapping); | |
| 2493 } | |
| 2494 else | |
| 2495 { | |
| 2496 probability | |
| 2497 = conditional_probability (node->right->subtree_prob, | |
| 2498 subtree_prob + default_prob); | |
| 2499 /* We cannot process node->right normally | |
| 2500 since we haven't ruled out the numbers less than | |
| 2501 this node's value. So handle node->right explicitly. */ | |
| 2502 bb = do_jump_if_equal (bb, index, node->right->low, | |
| 2503 node->right->case_bb, probability, | |
| 2504 phi_mapping); | |
| 2505 } | |
| 2506 } | |
| 2507 | |
| 2508 else if (node->right == 0 && node->left != 0) | |
| 2509 { | |
| 2510 /* Just one subtree, on the left. */ | |
| 2511 if (node->left->left || node->left->right | |
| 2512 || !tree_int_cst_equal (node->left->low, node->left->high)) | |
| 2513 { | |
| 2514 if (!node_has_high_bound (node, index_type)) | |
| 2515 { | |
| 2516 probability | |
| 2517 = conditional_probability (default_prob.apply_scale (1, 2), | |
| 2518 subtree_prob + default_prob); | |
| 2519 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2520 default_bb, probability, | |
| 2521 phi_mapping); | |
| 2522 default_prob = default_prob.apply_scale (1, 2); | |
| 2523 } | |
| 2524 | |
| 2525 bb = emit_case_nodes (bb, index, node->left, default_bb, | |
| 2526 default_label, default_prob, index_type, | |
| 2527 phi_mapping); | |
| 2528 } | |
| 2529 else | |
| 2530 { | |
| 2531 probability | |
| 2532 = conditional_probability (node->left->subtree_prob, | |
| 2533 subtree_prob + default_prob); | |
| 2534 /* We cannot process node->left normally | |
| 2535 since we haven't ruled out the numbers less than | |
| 2536 this node's value. So handle node->left explicitly. */ | |
| 2537 do_jump_if_equal (bb, index, node->left->low, node->left->case_bb, | |
| 2538 probability, phi_mapping); | |
| 2539 } | |
| 2540 } | |
| 2541 } | |
| 2542 else | |
| 2543 { | |
| 2544 /* Node is a range. These cases are very similar to those for a single | |
| 2545 value, except that we do not start by testing whether this node | |
| 2546 is the one to branch to. */ | |
| 2547 | |
| 2548 if (node->right != 0 && node->left != 0) | |
| 2549 { | |
| 2550 /* Node has subtrees on both sides. | |
| 2551 If the right-hand subtree is bounded, | |
| 2552 test for it first, since we can go straight there. | |
| 2553 Otherwise, we need to make a branch in the control structure, | |
| 2554 then handle the two subtrees. */ | |
| 2555 basic_block test_bb = NULL; | |
| 2556 | |
| 2557 if (node_is_bounded (node->right, index_type)) | |
| 2558 { | |
| 2559 /* Right hand node is fully bounded so we can eliminate any | |
| 2560 testing and branch directly to the target code. */ | |
| 2561 probability | |
| 2562 = conditional_probability (node->right->subtree_prob, | |
| 2563 subtree_prob + default_prob); | |
| 2564 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2565 node->right->case_bb, probability, | |
| 2566 phi_mapping); | |
| 2567 } | |
| 2568 else | |
| 2569 { | |
| 2570 /* Right hand node requires testing. | |
| 2571 Branch to a label where we will handle it later. */ | |
| 2572 | |
| 2573 test_bb = split_edge (single_succ_edge (bb)); | |
| 2574 redirect_edge_succ (single_pred_edge (test_bb), | |
| 2575 single_succ_edge (bb)->dest); | |
| 2576 | |
| 2577 probability | |
| 2578 = conditional_probability (node->right->subtree_prob | |
| 2579 + default_prob.apply_scale (1, 2), | |
| 2580 subtree_prob + default_prob); | |
| 2581 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2582 test_bb, probability, phi_mapping); | |
| 2583 default_prob = default_prob.apply_scale (1, 2); | |
| 2584 } | |
| 2585 | |
| 2586 /* Value belongs to this node or to the left-hand subtree. */ | |
| 2587 | |
| 2588 probability | |
| 2589 = conditional_probability (prob, subtree_prob + default_prob); | |
| 2590 bb = emit_cmp_and_jump_insns (bb, index, node->low, GE_EXPR, | |
| 2591 node->case_bb, probability, | |
| 2592 phi_mapping); | |
| 2593 | |
| 2594 /* Handle the left-hand subtree. */ | |
| 2595 bb = emit_case_nodes (bb, index, node->left, default_bb, | |
| 2596 default_label, default_prob, index_type, | |
| 2597 phi_mapping); | |
| 2598 | |
| 2599 /* If right node had to be handled later, do that now. */ | |
| 2600 if (test_bb) | |
| 2601 { | |
| 2602 /* If the left-hand subtree fell through, | |
| 2603 don't let it fall into the right-hand subtree. */ | |
| 2604 if (bb && default_bb) | |
| 2605 emit_jump (bb, default_bb, phi_mapping); | |
| 2606 | |
| 2607 bb = emit_case_nodes (test_bb, index, node->right, default_bb, | |
| 2608 default_label, default_prob, index_type, | |
| 2609 phi_mapping); | |
| 2610 } | |
| 2611 } | |
| 2612 | |
| 2613 else if (node->right != 0 && node->left == 0) | |
| 2614 { | |
| 2615 /* Deal with values to the left of this node, | |
| 2616 if they are possible. */ | |
| 2617 if (!node_has_low_bound (node, index_type)) | |
| 2618 { | |
| 2619 probability | |
| 2620 = conditional_probability (default_prob.apply_scale (1, 2), | |
| 2621 subtree_prob + default_prob); | |
| 2622 bb = emit_cmp_and_jump_insns (bb, index, node->low, LT_EXPR, | |
| 2623 default_bb, probability, | |
| 2624 phi_mapping); | |
| 2625 default_prob = default_prob.apply_scale (1, 2); | |
| 2626 } | |
| 2627 | |
| 2628 /* Value belongs to this node or to the right-hand subtree. */ | |
| 2629 | |
| 2630 probability | |
| 2631 = conditional_probability (prob, subtree_prob + default_prob); | |
| 2632 bb = emit_cmp_and_jump_insns (bb, index, node->high, LE_EXPR, | |
| 2633 node->case_bb, probability, | |
| 2634 phi_mapping); | |
| 2635 | |
| 2636 bb = emit_case_nodes (bb, index, node->right, default_bb, | |
| 2637 default_label, default_prob, index_type, | |
| 2638 phi_mapping); | |
| 2639 } | |
| 2640 | |
| 2641 else if (node->right == 0 && node->left != 0) | |
| 2642 { | |
| 2643 /* Deal with values to the right of this node, | |
| 2644 if they are possible. */ | |
| 2645 if (!node_has_high_bound (node, index_type)) | |
| 2646 { | |
| 2647 probability | |
| 2648 = conditional_probability (default_prob.apply_scale (1, 2), | |
| 2649 subtree_prob + default_prob); | |
| 2650 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2651 default_bb, probability, | |
| 2652 phi_mapping); | |
| 2653 default_prob = default_prob.apply_scale (1, 2); | |
| 2654 } | |
| 2655 | |
| 2656 /* Value belongs to this node or to the left-hand subtree. */ | |
| 2657 | |
| 2658 probability | |
| 2659 = conditional_probability (prob, subtree_prob + default_prob); | |
| 2660 bb = emit_cmp_and_jump_insns (bb, index, node->low, GE_EXPR, | |
| 2661 node->case_bb, probability, | |
| 2662 phi_mapping); | |
| 2663 | |
| 2664 bb = emit_case_nodes (bb, index, node->left, default_bb, | |
| 2665 default_label, default_prob, index_type, | |
| 2666 phi_mapping); | |
| 2667 } | |
| 2668 | |
| 2669 else | |
| 2670 { | |
| 2671 /* Node has no children so we check low and high bounds to remove | |
| 2672 redundant tests. Only one of the bounds can exist, | |
| 2673 since otherwise this node is bounded--a case tested already. */ | |
| 2674 bool high_bound = node_has_high_bound (node, index_type); | |
| 2675 bool low_bound = node_has_low_bound (node, index_type); | |
| 2676 | |
| 2677 if (!high_bound && low_bound) | |
| 2678 { | |
| 2679 probability | |
| 2680 = conditional_probability (default_prob, | |
| 2681 subtree_prob + default_prob); | |
| 2682 bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
| 2683 default_bb, probability, | |
| 2684 phi_mapping); | |
| 2685 } | |
| 2686 | |
| 2687 else if (!low_bound && high_bound) | |
| 2688 { | |
| 2689 probability | |
| 2690 = conditional_probability (default_prob, | |
| 2691 subtree_prob + default_prob); | |
| 2692 bb = emit_cmp_and_jump_insns (bb, index, node->low, LT_EXPR, | |
| 2693 default_bb, probability, | |
| 2694 phi_mapping); | |
| 2695 } | |
| 2696 else if (!low_bound && !high_bound) | |
| 2697 { | |
| 2698 tree lhs, rhs; | |
| 2699 generate_range_test (bb, index, node->low, node->high, | |
| 2700 &lhs, &rhs); | |
| 2701 probability | |
| 2702 = conditional_probability (default_prob, | |
| 2703 subtree_prob + default_prob); | |
| 2704 bb = emit_cmp_and_jump_insns (bb, lhs, rhs, GT_EXPR, | |
| 2705 default_bb, probability, | |
| 2706 phi_mapping); | |
| 2707 } | |
| 2708 | |
| 2709 emit_jump (bb, node->case_bb, phi_mapping); | |
| 2710 return NULL; | |
| 2711 } | |
| 2712 } | |
| 2713 | |
| 2714 return bb; | |
| 2715 } | |
| 2716 | |
| 2717 /* Search the parent sections of the case node tree | |
| 2718 to see if a test for the lower bound of NODE would be redundant. | |
| 2719 INDEX_TYPE is the type of the index expression. | |
| 2720 | |
| 2721 The instructions to generate the case decision tree are | |
| 2722 output in the same order as nodes are processed so it is | |
| 2723 known that if a parent node checks the range of the current | |
| 2724 node minus one that the current node is bounded at its lower | |
| 2725 span. Thus the test would be redundant. */ | |
| 2726 | |
| 2727 static bool | |
| 2728 node_has_low_bound (case_node_ptr node, tree index_type) | |
| 2729 { | |
| 2730 tree low_minus_one; | |
| 2731 case_node_ptr pnode; | |
| 2732 | |
| 2733 /* If the lower bound of this node is the lowest value in the index type, | |
| 2734 we need not test it. */ | |
| 2735 | |
| 2736 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type))) | |
| 2737 return true; | |
| 2738 | |
| 2739 /* If this node has a left branch, the value at the left must be less | |
| 2740 than that at this node, so it cannot be bounded at the bottom and | |
| 2741 we need not bother testing any further. */ | |
| 2742 | |
| 2743 if (node->left) | |
| 2744 return false; | |
| 2745 | |
| 2746 low_minus_one = fold_build2 (MINUS_EXPR, TREE_TYPE (node->low), node->low, | |
| 2747 build_int_cst (TREE_TYPE (node->low), 1)); | |
| 2748 | |
| 2749 /* If the subtraction above overflowed, we can't verify anything. | |
| 2750 Otherwise, look for a parent that tests our value - 1. */ | |
| 2751 | |
| 2752 if (!tree_int_cst_lt (low_minus_one, node->low)) | |
| 2753 return false; | |
| 2754 | |
| 2755 for (pnode = node->parent; pnode; pnode = pnode->parent) | |
| 2756 if (tree_int_cst_equal (low_minus_one, pnode->high)) | |
| 2757 return true; | |
| 2758 | |
| 2759 return false; | |
| 2760 } | |
| 2761 | |
| 2762 /* Search the parent sections of the case node tree | |
| 2763 to see if a test for the upper bound of NODE would be redundant. | |
| 2764 INDEX_TYPE is the type of the index expression. | |
| 2765 | |
| 2766 The instructions to generate the case decision tree are | |
| 2767 output in the same order as nodes are processed so it is | |
| 2768 known that if a parent node checks the range of the current | |
| 2769 node plus one that the current node is bounded at its upper | |
| 2770 span. Thus the test would be redundant. */ | |
| 2771 | |
| 2772 static bool | |
| 2773 node_has_high_bound (case_node_ptr node, tree index_type) | |
| 2774 { | |
| 2775 tree high_plus_one; | |
| 2776 case_node_ptr pnode; | |
| 2777 | |
| 2778 /* If there is no upper bound, obviously no test is needed. */ | |
| 2779 | |
| 2780 if (TYPE_MAX_VALUE (index_type) == NULL) | |
| 2781 return true; | |
| 2782 | |
| 2783 /* If the upper bound of this node is the highest value in the type | |
| 2784 of the index expression, we need not test against it. */ | |
| 2785 | |
| 2786 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type))) | |
| 2787 return true; | |
| 2788 | |
| 2789 /* If this node has a right branch, the value at the right must be greater | |
| 2790 than that at this node, so it cannot be bounded at the top and | |
| 2791 we need not bother testing any further. */ | |
| 2792 | |
| 2793 if (node->right) | |
| 2794 return false; | |
| 2795 | |
| 2796 high_plus_one = fold_build2 (PLUS_EXPR, TREE_TYPE (node->high), node->high, | |
| 2797 build_int_cst (TREE_TYPE (node->high), 1)); | |
| 2798 | |
| 2799 /* If the addition above overflowed, we can't verify anything. | |
| 2800 Otherwise, look for a parent that tests our value + 1. */ | |
| 2801 | |
| 2802 if (!tree_int_cst_lt (node->high, high_plus_one)) | |
| 2803 return false; | |
| 2804 | |
| 2805 for (pnode = node->parent; pnode; pnode = pnode->parent) | |
| 2806 if (tree_int_cst_equal (high_plus_one, pnode->low)) | |
| 2807 return true; | |
| 2808 | |
| 2809 return false; | |
| 2810 } | |
| 2811 | |
| 2812 /* Search the parent sections of the | |
| 2813 case node tree to see if both tests for the upper and lower | |
| 2814 bounds of NODE would be redundant. */ | |
| 2815 | |
| 2816 static bool | |
| 2817 node_is_bounded (case_node_ptr node, tree index_type) | |
| 2818 { | |
| 2819 return (node_has_low_bound (node, index_type) | |
| 2820 && node_has_high_bound (node, index_type)); | |
| 2821 } |