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8530c7be | 1 | /* Combining of if-expressions on trees. |
d353bf18 | 2 | Copyright (C) 2007-2015 Free Software Foundation, Inc. |
8530c7be | 3 | Contributed by Richard Guenther <rguenther@suse.de> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 9 | the Free Software Foundation; either version 3, or (at your option) |
8530c7be | 10 | any later version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
8530c7be | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
9ef16211 | 24 | #include "backend.h" |
25 | #include "tree.h" | |
26 | #include "gimple.h" | |
27 | #include "rtl.h" | |
28 | #include "ssa.h" | |
b4c65f30 | 29 | /* rtl is needed only because arm back-end requires it for |
30 | BRANCH_COST. */ | |
b4c65f30 | 31 | #include "tm_p.h" |
b20a8bb4 | 32 | #include "alias.h" |
b20a8bb4 | 33 | #include "fold-const.h" |
9ed99284 | 34 | #include "stor-layout.h" |
94ea8568 | 35 | #include "cfganal.h" |
ce084dfc | 36 | #include "tree-pretty-print.h" |
bc61cadb | 37 | #include "internal-fn.h" |
38 | #include "gimple-fold.h" | |
dcf1a1ec | 39 | #include "gimple-iterator.h" |
e795d6e1 | 40 | #include "gimplify-me.h" |
073c1fd5 | 41 | #include "tree-cfg.h" |
8530c7be | 42 | #include "tree-pass.h" |
8530c7be | 43 | |
b4c65f30 | 44 | #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT |
45 | #define LOGICAL_OP_NON_SHORT_CIRCUIT \ | |
46 | (BRANCH_COST (optimize_function_for_speed_p (cfun), \ | |
47 | false) >= 2) | |
48 | #endif | |
49 | ||
8530c7be | 50 | /* This pass combines COND_EXPRs to simplify control flow. It |
51 | currently recognizes bit tests and comparisons in chains that | |
52 | represent logical and or logical or of two COND_EXPRs. | |
53 | ||
54 | It does so by walking basic blocks in a approximate reverse | |
55 | post-dominator order and trying to match CFG patterns that | |
56 | represent logical and or logical or of two COND_EXPRs. | |
57 | Transformations are done if the COND_EXPR conditions match | |
58 | either | |
59 | ||
60 | 1. two single bit tests X & (1 << Yn) (for logical and) | |
61 | ||
62 | 2. two bit tests X & Yn (for logical or) | |
63 | ||
64 | 3. two comparisons X OPn Y (for logical or) | |
65 | ||
66 | To simplify this pass, removing basic blocks and dead code | |
67 | is left to CFG cleanup and DCE. */ | |
68 | ||
69 | ||
70 | /* Recognize a if-then-else CFG pattern starting to match with the | |
71 | COND_BB basic-block containing the COND_EXPR. The recognized | |
72 | then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
73 | *THEN_BB and/or *ELSE_BB are already set, they are required to | |
74 | match the then and else basic-blocks to make the pattern match. | |
75 | Returns true if the pattern matched, false otherwise. */ | |
76 | ||
77 | static bool | |
78 | recognize_if_then_else (basic_block cond_bb, | |
79 | basic_block *then_bb, basic_block *else_bb) | |
80 | { | |
81 | edge t, e; | |
82 | ||
83 | if (EDGE_COUNT (cond_bb->succs) != 2) | |
84 | return false; | |
85 | ||
86 | /* Find the then/else edges. */ | |
87 | t = EDGE_SUCC (cond_bb, 0); | |
88 | e = EDGE_SUCC (cond_bb, 1); | |
89 | if (!(t->flags & EDGE_TRUE_VALUE)) | |
a4f59596 | 90 | std::swap (t, e); |
8530c7be | 91 | if (!(t->flags & EDGE_TRUE_VALUE) |
92 | || !(e->flags & EDGE_FALSE_VALUE)) | |
93 | return false; | |
94 | ||
95 | /* Check if the edge destinations point to the required block. */ | |
96 | if (*then_bb | |
97 | && t->dest != *then_bb) | |
98 | return false; | |
99 | if (*else_bb | |
100 | && e->dest != *else_bb) | |
101 | return false; | |
102 | ||
103 | if (!*then_bb) | |
104 | *then_bb = t->dest; | |
105 | if (!*else_bb) | |
106 | *else_bb = e->dest; | |
107 | ||
108 | return true; | |
109 | } | |
110 | ||
111 | /* Verify if the basic block BB does not have side-effects. Return | |
112 | true in this case, else false. */ | |
113 | ||
114 | static bool | |
115 | bb_no_side_effects_p (basic_block bb) | |
116 | { | |
75a70cf9 | 117 | gimple_stmt_iterator gsi; |
8530c7be | 118 | |
75a70cf9 | 119 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
8530c7be | 120 | { |
75a70cf9 | 121 | gimple stmt = gsi_stmt (gsi); |
8530c7be | 122 | |
ab8f103c | 123 | if (is_gimple_debug (stmt)) |
124 | continue; | |
125 | ||
b523dd6d | 126 | if (gimple_has_side_effects (stmt) |
ab8f103c | 127 | || gimple_could_trap_p (stmt) |
dd277d48 | 128 | || gimple_vuse (stmt)) |
8530c7be | 129 | return false; |
130 | } | |
131 | ||
132 | return true; | |
133 | } | |
134 | ||
9202fd6a | 135 | /* Return true if BB is an empty forwarder block to TO_BB. */ |
136 | ||
137 | static bool | |
138 | forwarder_block_to (basic_block bb, basic_block to_bb) | |
139 | { | |
140 | return empty_block_p (bb) | |
141 | && single_succ_p (bb) | |
142 | && single_succ (bb) == to_bb; | |
143 | } | |
144 | ||
8530c7be | 145 | /* Verify if all PHI node arguments in DEST for edges from BB1 or |
146 | BB2 to DEST are the same. This makes the CFG merge point | |
147 | free from side-effects. Return true in this case, else false. */ | |
148 | ||
149 | static bool | |
150 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
151 | { | |
152 | edge e1 = find_edge (bb1, dest); | |
153 | edge e2 = find_edge (bb2, dest); | |
1a91d914 | 154 | gphi_iterator gsi; |
155 | gphi *phi; | |
8530c7be | 156 | |
75a70cf9 | 157 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
158 | { | |
1a91d914 | 159 | phi = gsi.phi (); |
75a70cf9 | 160 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), |
161 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
162 | return false; | |
163 | } | |
8530c7be | 164 | |
165 | return true; | |
166 | } | |
167 | ||
c9686d06 | 168 | /* Return the best representative SSA name for CANDIDATE which is used |
169 | in a bit test. */ | |
170 | ||
171 | static tree | |
172 | get_name_for_bit_test (tree candidate) | |
173 | { | |
174 | /* Skip single-use names in favor of using the name from a | |
175 | non-widening conversion definition. */ | |
176 | if (TREE_CODE (candidate) == SSA_NAME | |
177 | && has_single_use (candidate)) | |
178 | { | |
75a70cf9 | 179 | gimple def_stmt = SSA_NAME_DEF_STMT (candidate); |
180 | if (is_gimple_assign (def_stmt) | |
854e8953 | 181 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
c9686d06 | 182 | { |
75a70cf9 | 183 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
184 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
185 | return gimple_assign_rhs1 (def_stmt); | |
c9686d06 | 186 | } |
187 | } | |
188 | ||
189 | return candidate; | |
190 | } | |
191 | ||
75a70cf9 | 192 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
8530c7be | 193 | statements. Store the name being tested in *NAME and the bit |
75a70cf9 | 194 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
8530c7be | 195 | Returns true if the pattern matched, false otherwise. */ |
196 | ||
197 | static bool | |
1a91d914 | 198 | recognize_single_bit_test (gcond *cond, tree *name, tree *bit, bool inv) |
8530c7be | 199 | { |
75a70cf9 | 200 | gimple stmt; |
8530c7be | 201 | |
202 | /* Get at the definition of the result of the bit test. */ | |
6e6b952b | 203 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
75a70cf9 | 204 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
205 | || !integer_zerop (gimple_cond_rhs (cond))) | |
8530c7be | 206 | return false; |
75a70cf9 | 207 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
208 | if (!is_gimple_assign (stmt)) | |
8530c7be | 209 | return false; |
8530c7be | 210 | |
211 | /* Look at which bit is tested. One form to recognize is | |
212 | D.1985_5 = state_3(D) >> control1_4(D); | |
213 | D.1986_6 = (int) D.1985_5; | |
214 | D.1987_7 = op0 & 1; | |
215 | if (D.1987_7 != 0) */ | |
75a70cf9 | 216 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
217 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
218 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
8530c7be | 219 | { |
75a70cf9 | 220 | tree orig_name = gimple_assign_rhs1 (stmt); |
d9022390 | 221 | |
222 | /* Look through copies and conversions to eventually | |
223 | find the stmt that computes the shift. */ | |
75a70cf9 | 224 | stmt = SSA_NAME_DEF_STMT (orig_name); |
225 | ||
226 | while (is_gimple_assign (stmt) | |
854e8953 | 227 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
228 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
48331bf4 | 229 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))) |
230 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
854e8953 | 231 | || gimple_assign_ssa_name_copy_p (stmt))) |
232 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
8530c7be | 233 | |
d9022390 | 234 | /* If we found such, decompose it. */ |
75a70cf9 | 235 | if (is_gimple_assign (stmt) |
236 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
8530c7be | 237 | { |
238 | /* op0 & (1 << op1) */ | |
75a70cf9 | 239 | *bit = gimple_assign_rhs2 (stmt); |
240 | *name = gimple_assign_rhs1 (stmt); | |
8530c7be | 241 | } |
242 | else | |
243 | { | |
244 | /* t & 1 */ | |
d9022390 | 245 | *bit = integer_zero_node; |
c9686d06 | 246 | *name = get_name_for_bit_test (orig_name); |
8530c7be | 247 | } |
248 | ||
249 | return true; | |
250 | } | |
251 | ||
252 | /* Another form is | |
253 | D.1987_7 = op0 & (1 << CST) | |
254 | if (D.1987_7 != 0) */ | |
75a70cf9 | 255 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
256 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
257 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
8530c7be | 258 | { |
75a70cf9 | 259 | *name = gimple_assign_rhs1 (stmt); |
8530c7be | 260 | *bit = build_int_cst (integer_type_node, |
75a70cf9 | 261 | tree_log2 (gimple_assign_rhs2 (stmt))); |
8530c7be | 262 | return true; |
263 | } | |
264 | ||
265 | /* Another form is | |
266 | D.1986_6 = 1 << control1_4(D) | |
267 | D.1987_7 = op0 & D.1986_6 | |
268 | if (D.1987_7 != 0) */ | |
75a70cf9 | 269 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
270 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
271 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
8530c7be | 272 | { |
75a70cf9 | 273 | gimple tmp; |
8530c7be | 274 | |
275 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
276 | specifying expression. */ | |
75a70cf9 | 277 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
278 | if (is_gimple_assign (tmp) | |
279 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
280 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
8530c7be | 281 | { |
75a70cf9 | 282 | *name = gimple_assign_rhs2 (stmt); |
283 | *bit = gimple_assign_rhs2 (tmp); | |
8530c7be | 284 | return true; |
285 | } | |
286 | ||
75a70cf9 | 287 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
288 | if (is_gimple_assign (tmp) | |
289 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
290 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
8530c7be | 291 | { |
75a70cf9 | 292 | *name = gimple_assign_rhs1 (stmt); |
293 | *bit = gimple_assign_rhs2 (tmp); | |
8530c7be | 294 | return true; |
295 | } | |
296 | } | |
297 | ||
298 | return false; | |
299 | } | |
300 | ||
75a70cf9 | 301 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
8530c7be | 302 | statements. Store the name being tested in *NAME and the bits |
303 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
304 | Returns true if the pattern matched, false otherwise. */ | |
305 | ||
306 | static bool | |
1a91d914 | 307 | recognize_bits_test (gcond *cond, tree *name, tree *bits, bool inv) |
8530c7be | 308 | { |
75a70cf9 | 309 | gimple stmt; |
8530c7be | 310 | |
311 | /* Get at the definition of the result of the bit test. */ | |
6e6b952b | 312 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
75a70cf9 | 313 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
314 | || !integer_zerop (gimple_cond_rhs (cond))) | |
8530c7be | 315 | return false; |
75a70cf9 | 316 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
317 | if (!is_gimple_assign (stmt) | |
318 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
8530c7be | 319 | return false; |
320 | ||
75a70cf9 | 321 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
322 | *bits = gimple_assign_rhs2 (stmt); | |
8530c7be | 323 | |
324 | return true; | |
325 | } | |
326 | ||
327 | /* If-convert on a and pattern with a common else block. The inner | |
328 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
6e6b952b | 329 | inner_inv, outer_inv and result_inv indicate whether the conditions |
330 | are inverted. | |
8530c7be | 331 | Returns true if the edges to the common else basic-block were merged. */ |
332 | ||
333 | static bool | |
6e6b952b | 334 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
335 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
8530c7be | 336 | { |
75a70cf9 | 337 | gimple_stmt_iterator gsi; |
1a91d914 | 338 | gimple inner_stmt, outer_stmt; |
339 | gcond *inner_cond, *outer_cond; | |
6e6b952b | 340 | tree name1, name2, bit1, bit2, bits1, bits2; |
8530c7be | 341 | |
1a91d914 | 342 | inner_stmt = last_stmt (inner_cond_bb); |
343 | if (!inner_stmt | |
344 | || gimple_code (inner_stmt) != GIMPLE_COND) | |
8530c7be | 345 | return false; |
1a91d914 | 346 | inner_cond = as_a <gcond *> (inner_stmt); |
8530c7be | 347 | |
1a91d914 | 348 | outer_stmt = last_stmt (outer_cond_bb); |
349 | if (!outer_stmt | |
350 | || gimple_code (outer_stmt) != GIMPLE_COND) | |
8530c7be | 351 | return false; |
1a91d914 | 352 | outer_cond = as_a <gcond *> (outer_stmt); |
8530c7be | 353 | |
354 | /* See if we test a single bit of the same name in both tests. In | |
355 | that case remove the outer test, merging both else edges, | |
356 | and change the inner one to test for | |
357 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
6e6b952b | 358 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
359 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
8530c7be | 360 | && name1 == name2) |
361 | { | |
362 | tree t, t2; | |
363 | ||
364 | /* Do it. */ | |
75a70cf9 | 365 | gsi = gsi_for_stmt (inner_cond); |
8530c7be | 366 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
9289fc25 | 367 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
8530c7be | 368 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
9289fc25 | 369 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
8530c7be | 370 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
75a70cf9 | 371 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
372 | true, GSI_SAME_STMT); | |
8530c7be | 373 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
75a70cf9 | 374 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
375 | true, GSI_SAME_STMT); | |
6e6b952b | 376 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
377 | boolean_type_node, t2, t); | |
b611dd5f | 378 | t = canonicalize_cond_expr_cond (t); |
379 | if (!t) | |
380 | return false; | |
75a70cf9 | 381 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 382 | update_stmt (inner_cond); |
383 | ||
384 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 385 | gimple_cond_set_condition_from_tree (outer_cond, |
386 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 387 | update_stmt (outer_cond); |
388 | ||
389 | if (dump_file) | |
390 | { | |
391 | fprintf (dump_file, "optimizing double bit test to "); | |
392 | print_generic_expr (dump_file, name1, 0); | |
393 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); | |
394 | print_generic_expr (dump_file, bit1, 0); | |
395 | fprintf (dump_file, ") | (1 << "); | |
396 | print_generic_expr (dump_file, bit2, 0); | |
397 | fprintf (dump_file, ")\n"); | |
398 | } | |
399 | ||
400 | return true; | |
401 | } | |
402 | ||
8530c7be | 403 | /* See if we have two bit tests of the same name in both tests. |
404 | In that case remove the outer test and change the inner one to | |
405 | test for name & (bits1 | bits2) != 0. */ | |
6e6b952b | 406 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
407 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
8530c7be | 408 | { |
75a70cf9 | 409 | gimple_stmt_iterator gsi; |
8530c7be | 410 | tree t; |
411 | ||
412 | /* Find the common name which is bit-tested. */ | |
413 | if (name1 == name2) | |
414 | ; | |
415 | else if (bits1 == bits2) | |
416 | { | |
dfcf26a5 | 417 | std::swap (name2, bits2); |
418 | std::swap (name1, bits1); | |
8530c7be | 419 | } |
420 | else if (name1 == bits2) | |
dfcf26a5 | 421 | std::swap (name2, bits2); |
8530c7be | 422 | else if (bits1 == name2) |
dfcf26a5 | 423 | std::swap (name1, bits1); |
8530c7be | 424 | else |
425 | return false; | |
426 | ||
2a8d660d | 427 | /* As we strip non-widening conversions in finding a common |
428 | name that is tested make sure to end up with an integral | |
429 | type for building the bit operations. */ | |
430 | if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
431 | >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
432 | { | |
433 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
434 | name1 = fold_convert (TREE_TYPE (bits1), name1); | |
435 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
436 | bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
437 | } | |
438 | else | |
439 | { | |
440 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
441 | name1 = fold_convert (TREE_TYPE (bits2), name1); | |
442 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
443 | bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
444 | } | |
445 | ||
8530c7be | 446 | /* Do it. */ |
75a70cf9 | 447 | gsi = gsi_for_stmt (inner_cond); |
8530c7be | 448 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); |
75a70cf9 | 449 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
450 | true, GSI_SAME_STMT); | |
8530c7be | 451 | t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
75a70cf9 | 452 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
453 | true, GSI_SAME_STMT); | |
6e6b952b | 454 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
75a70cf9 | 455 | build_int_cst (TREE_TYPE (t), 0)); |
b611dd5f | 456 | t = canonicalize_cond_expr_cond (t); |
457 | if (!t) | |
458 | return false; | |
75a70cf9 | 459 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 460 | update_stmt (inner_cond); |
461 | ||
462 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 463 | gimple_cond_set_condition_from_tree (outer_cond, |
464 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 465 | update_stmt (outer_cond); |
466 | ||
467 | if (dump_file) | |
468 | { | |
469 | fprintf (dump_file, "optimizing bits or bits test to "); | |
470 | print_generic_expr (dump_file, name1, 0); | |
471 | fprintf (dump_file, " & T != 0\nwith temporary T = "); | |
472 | print_generic_expr (dump_file, bits1, 0); | |
473 | fprintf (dump_file, " | "); | |
474 | print_generic_expr (dump_file, bits2, 0); | |
475 | fprintf (dump_file, "\n"); | |
476 | } | |
477 | ||
478 | return true; | |
479 | } | |
480 | ||
6e6b952b | 481 | /* See if we have two comparisons that we can merge into one. */ |
482 | else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
c82d157a | 483 | && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
8530c7be | 484 | { |
8530c7be | 485 | tree t; |
6e6b952b | 486 | enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
487 | enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
488 | ||
489 | /* Invert comparisons if necessary (and possible). */ | |
490 | if (inner_inv) | |
491 | inner_cond_code = invert_tree_comparison (inner_cond_code, | |
93633022 | 492 | HONOR_NANS (gimple_cond_lhs (inner_cond))); |
6e6b952b | 493 | if (inner_cond_code == ERROR_MARK) |
494 | return false; | |
495 | if (outer_inv) | |
496 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
93633022 | 497 | HONOR_NANS (gimple_cond_lhs (outer_cond))); |
6e6b952b | 498 | if (outer_cond_code == ERROR_MARK) |
499 | return false; | |
500 | /* Don't return false so fast, try maybe_fold_or_comparisons? */ | |
8530c7be | 501 | |
6e6b952b | 502 | if (!(t = maybe_fold_and_comparisons (inner_cond_code, |
503 | gimple_cond_lhs (inner_cond), | |
504 | gimple_cond_rhs (inner_cond), | |
505 | outer_cond_code, | |
506 | gimple_cond_lhs (outer_cond), | |
507 | gimple_cond_rhs (outer_cond)))) | |
b4c65f30 | 508 | { |
509 | tree t1, t2; | |
510 | gimple_stmt_iterator gsi; | |
511 | if (!LOGICAL_OP_NON_SHORT_CIRCUIT) | |
512 | return false; | |
513 | /* Only do this optimization if the inner bb contains only the conditional. */ | |
514 | if (!gsi_one_before_end_p (gsi_start_nondebug_after_labels_bb (inner_cond_bb))) | |
515 | return false; | |
516 | t1 = fold_build2_loc (gimple_location (inner_cond), | |
517 | inner_cond_code, | |
518 | boolean_type_node, | |
519 | gimple_cond_lhs (inner_cond), | |
520 | gimple_cond_rhs (inner_cond)); | |
521 | t2 = fold_build2_loc (gimple_location (outer_cond), | |
522 | outer_cond_code, | |
523 | boolean_type_node, | |
524 | gimple_cond_lhs (outer_cond), | |
525 | gimple_cond_rhs (outer_cond)); | |
526 | t = fold_build2_loc (gimple_location (inner_cond), | |
527 | TRUTH_AND_EXPR, boolean_type_node, t1, t2); | |
528 | if (result_inv) | |
529 | { | |
530 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
531 | result_inv = false; | |
532 | } | |
533 | gsi = gsi_for_stmt (inner_cond); | |
534 | t = force_gimple_operand_gsi_1 (&gsi, t, is_gimple_condexpr, NULL, true, | |
535 | GSI_SAME_STMT); | |
536 | } | |
6e6b952b | 537 | if (result_inv) |
538 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
a7392604 | 539 | t = canonicalize_cond_expr_cond (t); |
540 | if (!t) | |
541 | return false; | |
75a70cf9 | 542 | gimple_cond_set_condition_from_tree (inner_cond, t); |
8530c7be | 543 | update_stmt (inner_cond); |
544 | ||
545 | /* Leave CFG optimization to cfg_cleanup. */ | |
6e6b952b | 546 | gimple_cond_set_condition_from_tree (outer_cond, |
547 | outer_inv ? boolean_false_node : boolean_true_node); | |
8530c7be | 548 | update_stmt (outer_cond); |
549 | ||
550 | if (dump_file) | |
551 | { | |
552 | fprintf (dump_file, "optimizing two comparisons to "); | |
553 | print_generic_expr (dump_file, t, 0); | |
554 | fprintf (dump_file, "\n"); | |
555 | } | |
556 | ||
557 | return true; | |
558 | } | |
559 | ||
560 | return false; | |
561 | } | |
562 | ||
9202fd6a | 563 | /* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and |
564 | dispatch to the appropriate if-conversion helper for a particular | |
565 | set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. | |
566 | PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ | |
567 | ||
568 | static bool | |
569 | tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, | |
570 | basic_block then_bb, basic_block else_bb, | |
571 | basic_block phi_pred_bb) | |
572 | { | |
573 | /* The && form is characterized by a common else_bb with | |
574 | the two edges leading to it mergable. The latter is | |
575 | guaranteed by matching PHI arguments in the else_bb and | |
576 | the inner cond_bb having no side-effects. */ | |
577 | if (phi_pred_bb != else_bb | |
578 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
579 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) | |
580 | && bb_no_side_effects_p (inner_cond_bb)) | |
581 | { | |
582 | /* We have | |
583 | <outer_cond_bb> | |
584 | if (q) goto inner_cond_bb; else goto else_bb; | |
585 | <inner_cond_bb> | |
586 | if (p) goto ...; else goto else_bb; | |
587 | ... | |
588 | <else_bb> | |
589 | ... | |
590 | */ | |
591 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, | |
592 | false); | |
593 | } | |
594 | ||
595 | /* And a version where the outer condition is negated. */ | |
596 | if (phi_pred_bb != else_bb | |
597 | && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
598 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) | |
599 | && bb_no_side_effects_p (inner_cond_bb)) | |
600 | { | |
601 | /* We have | |
602 | <outer_cond_bb> | |
603 | if (q) goto else_bb; else goto inner_cond_bb; | |
604 | <inner_cond_bb> | |
605 | if (p) goto ...; else goto else_bb; | |
606 | ... | |
607 | <else_bb> | |
608 | ... | |
609 | */ | |
610 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
611 | false); | |
612 | } | |
613 | ||
614 | /* The || form is characterized by a common then_bb with the | |
615 | two edges leading to it mergable. The latter is guaranteed | |
616 | by matching PHI arguments in the then_bb and the inner cond_bb | |
617 | having no side-effects. */ | |
618 | if (phi_pred_bb != then_bb | |
619 | && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
620 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) | |
621 | && bb_no_side_effects_p (inner_cond_bb)) | |
622 | { | |
623 | /* We have | |
624 | <outer_cond_bb> | |
625 | if (q) goto then_bb; else goto inner_cond_bb; | |
626 | <inner_cond_bb> | |
627 | if (q) goto then_bb; else goto ...; | |
628 | <then_bb> | |
629 | ... | |
630 | */ | |
631 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, | |
632 | true); | |
633 | } | |
634 | ||
635 | /* And a version where the outer condition is negated. */ | |
636 | if (phi_pred_bb != then_bb | |
637 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
638 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) | |
639 | && bb_no_side_effects_p (inner_cond_bb)) | |
640 | { | |
641 | /* We have | |
642 | <outer_cond_bb> | |
643 | if (q) goto inner_cond_bb; else goto then_bb; | |
644 | <inner_cond_bb> | |
645 | if (q) goto then_bb; else goto ...; | |
646 | <then_bb> | |
647 | ... | |
648 | */ | |
649 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
650 | true); | |
651 | } | |
652 | ||
653 | return false; | |
654 | } | |
655 | ||
8530c7be | 656 | /* Recognize a CFG pattern and dispatch to the appropriate |
657 | if-conversion helper. We start with BB as the innermost | |
658 | worker basic-block. Returns true if a transformation was done. */ | |
659 | ||
660 | static bool | |
661 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
662 | { | |
663 | basic_block then_bb = NULL, else_bb = NULL; | |
664 | ||
665 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
666 | return false; | |
667 | ||
668 | /* Recognize && and || of two conditions with a common | |
669 | then/else block which entry edges we can merge. That is: | |
670 | if (a || b) | |
671 | ; | |
672 | and | |
673 | if (a && b) | |
674 | ; | |
675 | This requires a single predecessor of the inner cond_bb. */ | |
676 | if (single_pred_p (inner_cond_bb)) | |
677 | { | |
678 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
679 | ||
9202fd6a | 680 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, |
681 | then_bb, else_bb, inner_cond_bb)) | |
682 | return true; | |
6e6b952b | 683 | |
9202fd6a | 684 | if (forwarder_block_to (else_bb, then_bb)) |
6e6b952b | 685 | { |
9202fd6a | 686 | /* Other possibilities for the && form, if else_bb is |
687 | empty forwarder block to then_bb. Compared to the above simpler | |
688 | forms this can be treated as if then_bb and else_bb were swapped, | |
689 | and the corresponding inner_cond_bb not inverted because of that. | |
690 | For same_phi_args_p we look at equality of arguments between | |
691 | edge from outer_cond_bb and the forwarder block. */ | |
692 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
693 | then_bb, else_bb)) | |
694 | return true; | |
8530c7be | 695 | } |
9202fd6a | 696 | else if (forwarder_block_to (then_bb, else_bb)) |
6e6b952b | 697 | { |
9202fd6a | 698 | /* Other possibilities for the || form, if then_bb is |
699 | empty forwarder block to else_bb. Compared to the above simpler | |
700 | forms this can be treated as if then_bb and else_bb were swapped, | |
701 | and the corresponding inner_cond_bb not inverted because of that. | |
702 | For same_phi_args_p we look at equality of arguments between | |
703 | edge from outer_cond_bb and the forwarder block. */ | |
704 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
705 | then_bb, then_bb)) | |
706 | return true; | |
8530c7be | 707 | } |
708 | } | |
709 | ||
710 | return false; | |
711 | } | |
712 | ||
713 | /* Main entry for the tree if-conversion pass. */ | |
714 | ||
65b0537f | 715 | namespace { |
716 | ||
717 | const pass_data pass_data_tree_ifcombine = | |
718 | { | |
719 | GIMPLE_PASS, /* type */ | |
720 | "ifcombine", /* name */ | |
721 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 722 | TV_TREE_IFCOMBINE, /* tv_id */ |
723 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
724 | 0, /* properties_provided */ | |
725 | 0, /* properties_destroyed */ | |
726 | 0, /* todo_flags_start */ | |
8b88439e | 727 | TODO_update_ssa, /* todo_flags_finish */ |
65b0537f | 728 | }; |
729 | ||
730 | class pass_tree_ifcombine : public gimple_opt_pass | |
731 | { | |
732 | public: | |
733 | pass_tree_ifcombine (gcc::context *ctxt) | |
734 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
735 | {} | |
736 | ||
737 | /* opt_pass methods: */ | |
738 | virtual unsigned int execute (function *); | |
739 | ||
740 | }; // class pass_tree_ifcombine | |
741 | ||
742 | unsigned int | |
743 | pass_tree_ifcombine::execute (function *fun) | |
8530c7be | 744 | { |
745 | basic_block *bbs; | |
746 | bool cfg_changed = false; | |
747 | int i; | |
748 | ||
ba4d2b2f | 749 | bbs = single_pred_before_succ_order (); |
8a245b9d | 750 | calculate_dominance_info (CDI_DOMINATORS); |
8530c7be | 751 | |
b4c65f30 | 752 | /* Search every basic block for COND_EXPR we may be able to optimize. |
753 | ||
754 | We walk the blocks in order that guarantees that a block with | |
755 | a single predecessor is processed after the predecessor. | |
756 | This ensures that we collapse outter ifs before visiting the | |
757 | inner ones, and also that we do not try to visit a removed | |
758 | block. This is opposite of PHI-OPT, because we cascade the | |
759 | combining rather than cascading PHIs. */ | |
65b0537f | 760 | for (i = n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) |
8530c7be | 761 | { |
762 | basic_block bb = bbs[i]; | |
75a70cf9 | 763 | gimple stmt = last_stmt (bb); |
8530c7be | 764 | |
765 | if (stmt | |
75a70cf9 | 766 | && gimple_code (stmt) == GIMPLE_COND) |
8530c7be | 767 | cfg_changed |= tree_ssa_ifcombine_bb (bb); |
768 | } | |
769 | ||
770 | free (bbs); | |
771 | ||
772 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
773 | } | |
774 | ||
cbe8bda8 | 775 | } // anon namespace |
776 | ||
777 | gimple_opt_pass * | |
778 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
779 | { | |
780 | return new pass_tree_ifcombine (ctxt); | |
781 | } |