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18d08014 | 1 | /* Combining of if-expressions on trees. |
85ec4feb | 2 | Copyright (C) 2007-2018 Free Software Foundation, Inc. |
18d08014 RG |
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 | |
9dcd6f09 | 9 | the Free Software Foundation; either version 3, or (at your option) |
18d08014 RG |
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 | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
18d08014 RG |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
c7131fb2 | 24 | #include "backend.h" |
957060b5 | 25 | #include "rtl.h" |
c7131fb2 AM |
26 | #include "tree.h" |
27 | #include "gimple.h" | |
957060b5 AM |
28 | #include "cfghooks.h" |
29 | #include "tree-pass.h" | |
4d0cdd0c | 30 | #include "memmodel.h" |
957060b5 | 31 | #include "tm_p.h" |
c7131fb2 | 32 | #include "ssa.h" |
957060b5 | 33 | #include "tree-pretty-print.h" |
5d2a9da9 AP |
34 | /* rtl is needed only because arm back-end requires it for |
35 | BRANCH_COST. */ | |
40e23961 | 36 | #include "fold-const.h" |
60393bbc | 37 | #include "cfganal.h" |
2fb9a547 | 38 | #include "gimple-fold.h" |
5be5c238 | 39 | #include "gimple-iterator.h" |
18f429e2 | 40 | #include "gimplify-me.h" |
442b4905 | 41 | #include "tree-cfg.h" |
828ca3d8 | 42 | #include "tree-ssa.h" |
18d08014 | 43 | |
5d2a9da9 AP |
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 | ||
18d08014 RG |
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)) | |
6b4db501 | 90 | std::swap (t, e); |
18d08014 RG |
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 | { | |
726a989a | 117 | gimple_stmt_iterator gsi; |
18d08014 | 118 | |
726a989a | 119 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
18d08014 | 120 | { |
355fe088 | 121 | gimple *stmt = gsi_stmt (gsi); |
18d08014 | 122 | |
597c6315 RB |
123 | if (is_gimple_debug (stmt)) |
124 | continue; | |
125 | ||
179184e3 | 126 | if (gimple_has_side_effects (stmt) |
828ca3d8 | 127 | || gimple_uses_undefined_value_p (stmt) |
597c6315 | 128 | || gimple_could_trap_p (stmt) |
f55460af JJ |
129 | || gimple_vuse (stmt) |
130 | /* const calls don't match any of the above, yet they could | |
131 | still have some side-effects - they could contain | |
132 | gimple_could_trap_p statements, like floating point | |
133 | exceptions or integer division by zero. See PR70586. | |
134 | FIXME: perhaps gimple_has_side_effects or gimple_could_trap_p | |
135 | should handle this. */ | |
136 | || is_gimple_call (stmt)) | |
18d08014 RG |
137 | return false; |
138 | } | |
139 | ||
140 | return true; | |
141 | } | |
142 | ||
bf4787b2 JJ |
143 | /* Return true if BB is an empty forwarder block to TO_BB. */ |
144 | ||
145 | static bool | |
146 | forwarder_block_to (basic_block bb, basic_block to_bb) | |
147 | { | |
148 | return empty_block_p (bb) | |
149 | && single_succ_p (bb) | |
150 | && single_succ (bb) == to_bb; | |
151 | } | |
152 | ||
18d08014 RG |
153 | /* Verify if all PHI node arguments in DEST for edges from BB1 or |
154 | BB2 to DEST are the same. This makes the CFG merge point | |
155 | free from side-effects. Return true in this case, else false. */ | |
156 | ||
157 | static bool | |
158 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
159 | { | |
160 | edge e1 = find_edge (bb1, dest); | |
161 | edge e2 = find_edge (bb2, dest); | |
538dd0b7 DM |
162 | gphi_iterator gsi; |
163 | gphi *phi; | |
18d08014 | 164 | |
726a989a RB |
165 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
166 | { | |
538dd0b7 | 167 | phi = gsi.phi (); |
726a989a RB |
168 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), |
169 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
170 | return false; | |
171 | } | |
18d08014 RG |
172 | |
173 | return true; | |
174 | } | |
175 | ||
d7b339dd RG |
176 | /* Return the best representative SSA name for CANDIDATE which is used |
177 | in a bit test. */ | |
178 | ||
179 | static tree | |
180 | get_name_for_bit_test (tree candidate) | |
181 | { | |
182 | /* Skip single-use names in favor of using the name from a | |
183 | non-widening conversion definition. */ | |
184 | if (TREE_CODE (candidate) == SSA_NAME | |
185 | && has_single_use (candidate)) | |
186 | { | |
355fe088 | 187 | gimple *def_stmt = SSA_NAME_DEF_STMT (candidate); |
726a989a | 188 | if (is_gimple_assign (def_stmt) |
a6450905 | 189 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
d7b339dd | 190 | { |
726a989a RB |
191 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
192 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
193 | return gimple_assign_rhs1 (def_stmt); | |
d7b339dd RG |
194 | } |
195 | } | |
196 | ||
197 | return candidate; | |
198 | } | |
199 | ||
726a989a | 200 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
18d08014 | 201 | statements. Store the name being tested in *NAME and the bit |
726a989a | 202 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
18d08014 RG |
203 | Returns true if the pattern matched, false otherwise. */ |
204 | ||
205 | static bool | |
538dd0b7 | 206 | recognize_single_bit_test (gcond *cond, tree *name, tree *bit, bool inv) |
18d08014 | 207 | { |
355fe088 | 208 | gimple *stmt; |
18d08014 RG |
209 | |
210 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 211 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
212 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
213 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 214 | return false; |
726a989a RB |
215 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
216 | if (!is_gimple_assign (stmt)) | |
18d08014 | 217 | return false; |
18d08014 RG |
218 | |
219 | /* Look at which bit is tested. One form to recognize is | |
220 | D.1985_5 = state_3(D) >> control1_4(D); | |
221 | D.1986_6 = (int) D.1985_5; | |
222 | D.1987_7 = op0 & 1; | |
223 | if (D.1987_7 != 0) */ | |
726a989a RB |
224 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
225 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
226 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
18d08014 | 227 | { |
726a989a | 228 | tree orig_name = gimple_assign_rhs1 (stmt); |
b0569227 RG |
229 | |
230 | /* Look through copies and conversions to eventually | |
231 | find the stmt that computes the shift. */ | |
726a989a RB |
232 | stmt = SSA_NAME_DEF_STMT (orig_name); |
233 | ||
234 | while (is_gimple_assign (stmt) | |
a6450905 RG |
235 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
236 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
14e000de JJ |
237 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))) |
238 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
a6450905 RG |
239 | || gimple_assign_ssa_name_copy_p (stmt))) |
240 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
18d08014 | 241 | |
b0569227 | 242 | /* If we found such, decompose it. */ |
726a989a RB |
243 | if (is_gimple_assign (stmt) |
244 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
18d08014 RG |
245 | { |
246 | /* op0 & (1 << op1) */ | |
726a989a RB |
247 | *bit = gimple_assign_rhs2 (stmt); |
248 | *name = gimple_assign_rhs1 (stmt); | |
18d08014 RG |
249 | } |
250 | else | |
251 | { | |
252 | /* t & 1 */ | |
b0569227 | 253 | *bit = integer_zero_node; |
d7b339dd | 254 | *name = get_name_for_bit_test (orig_name); |
18d08014 RG |
255 | } |
256 | ||
257 | return true; | |
258 | } | |
259 | ||
260 | /* Another form is | |
261 | D.1987_7 = op0 & (1 << CST) | |
262 | if (D.1987_7 != 0) */ | |
726a989a RB |
263 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
264 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
265 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
18d08014 | 266 | { |
726a989a | 267 | *name = gimple_assign_rhs1 (stmt); |
18d08014 | 268 | *bit = build_int_cst (integer_type_node, |
726a989a | 269 | tree_log2 (gimple_assign_rhs2 (stmt))); |
18d08014 RG |
270 | return true; |
271 | } | |
272 | ||
273 | /* Another form is | |
274 | D.1986_6 = 1 << control1_4(D) | |
275 | D.1987_7 = op0 & D.1986_6 | |
276 | if (D.1987_7 != 0) */ | |
726a989a RB |
277 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
278 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
279 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
18d08014 | 280 | { |
355fe088 | 281 | gimple *tmp; |
18d08014 RG |
282 | |
283 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
284 | specifying expression. */ | |
726a989a RB |
285 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
286 | if (is_gimple_assign (tmp) | |
287 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
288 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 289 | { |
726a989a RB |
290 | *name = gimple_assign_rhs2 (stmt); |
291 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
292 | return true; |
293 | } | |
294 | ||
726a989a RB |
295 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
296 | if (is_gimple_assign (tmp) | |
297 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
298 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 299 | { |
726a989a RB |
300 | *name = gimple_assign_rhs1 (stmt); |
301 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
302 | return true; |
303 | } | |
304 | } | |
305 | ||
306 | return false; | |
307 | } | |
308 | ||
726a989a | 309 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
18d08014 RG |
310 | statements. Store the name being tested in *NAME and the bits |
311 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
312 | Returns true if the pattern matched, false otherwise. */ | |
313 | ||
314 | static bool | |
538dd0b7 | 315 | recognize_bits_test (gcond *cond, tree *name, tree *bits, bool inv) |
18d08014 | 316 | { |
355fe088 | 317 | gimple *stmt; |
18d08014 RG |
318 | |
319 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 320 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
321 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
322 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 323 | return false; |
726a989a RB |
324 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
325 | if (!is_gimple_assign (stmt) | |
326 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
18d08014 RG |
327 | return false; |
328 | ||
726a989a RB |
329 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
330 | *bits = gimple_assign_rhs2 (stmt); | |
18d08014 RG |
331 | |
332 | return true; | |
333 | } | |
334 | ||
30c6ec2f JH |
335 | |
336 | /* Update profile after code in outer_cond_bb was adjusted so | |
337 | outer_cond_bb has no condition. */ | |
338 | ||
339 | static void | |
340 | update_profile_after_ifcombine (basic_block inner_cond_bb, | |
341 | basic_block outer_cond_bb) | |
342 | { | |
343 | edge outer_to_inner = find_edge (outer_cond_bb, inner_cond_bb); | |
344 | edge outer2 = (EDGE_SUCC (outer_cond_bb, 0) == outer_to_inner | |
345 | ? EDGE_SUCC (outer_cond_bb, 1) | |
346 | : EDGE_SUCC (outer_cond_bb, 0)); | |
347 | edge inner_taken = EDGE_SUCC (inner_cond_bb, 0); | |
348 | edge inner_not_taken = EDGE_SUCC (inner_cond_bb, 1); | |
349 | ||
350 | if (inner_taken->dest != outer2->dest) | |
351 | std::swap (inner_taken, inner_not_taken); | |
352 | gcc_assert (inner_taken->dest == outer2->dest); | |
353 | ||
354 | /* In the following we assume that inner_cond_bb has single predecessor. */ | |
355 | gcc_assert (single_pred_p (inner_cond_bb)); | |
356 | ||
357 | /* Path outer_cond_bb->(outer2) needs to be merged into path | |
358 | outer_cond_bb->(outer_to_inner)->inner_cond_bb->(inner_taken) | |
359 | and probability of inner_not_taken updated. */ | |
360 | ||
30c6ec2f | 361 | inner_cond_bb->count = outer_cond_bb->count; |
30c6ec2f | 362 | |
357067f2 JH |
363 | inner_taken->probability = outer2->probability + outer_to_inner->probability |
364 | * inner_taken->probability; | |
365 | inner_not_taken->probability = profile_probability::always () | |
30c6ec2f JH |
366 | - inner_taken->probability; |
367 | ||
357067f2 | 368 | outer_to_inner->probability = profile_probability::always (); |
357067f2 | 369 | outer2->probability = profile_probability::never (); |
30c6ec2f JH |
370 | } |
371 | ||
18d08014 RG |
372 | /* If-convert on a and pattern with a common else block. The inner |
373 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
777d77b3 MG |
374 | inner_inv, outer_inv and result_inv indicate whether the conditions |
375 | are inverted. | |
18d08014 RG |
376 | Returns true if the edges to the common else basic-block were merged. */ |
377 | ||
378 | static bool | |
777d77b3 MG |
379 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
380 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
18d08014 | 381 | { |
726a989a | 382 | gimple_stmt_iterator gsi; |
355fe088 | 383 | gimple *inner_stmt, *outer_stmt; |
538dd0b7 | 384 | gcond *inner_cond, *outer_cond; |
777d77b3 | 385 | tree name1, name2, bit1, bit2, bits1, bits2; |
18d08014 | 386 | |
538dd0b7 DM |
387 | inner_stmt = last_stmt (inner_cond_bb); |
388 | if (!inner_stmt | |
389 | || gimple_code (inner_stmt) != GIMPLE_COND) | |
18d08014 | 390 | return false; |
538dd0b7 | 391 | inner_cond = as_a <gcond *> (inner_stmt); |
18d08014 | 392 | |
538dd0b7 DM |
393 | outer_stmt = last_stmt (outer_cond_bb); |
394 | if (!outer_stmt | |
395 | || gimple_code (outer_stmt) != GIMPLE_COND) | |
18d08014 | 396 | return false; |
538dd0b7 | 397 | outer_cond = as_a <gcond *> (outer_stmt); |
18d08014 RG |
398 | |
399 | /* See if we test a single bit of the same name in both tests. In | |
400 | that case remove the outer test, merging both else edges, | |
401 | and change the inner one to test for | |
402 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
777d77b3 MG |
403 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
404 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
18d08014 RG |
405 | && name1 == name2) |
406 | { | |
407 | tree t, t2; | |
408 | ||
409 | /* Do it. */ | |
726a989a | 410 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 411 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 412 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
18d08014 | 413 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 414 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
18d08014 | 415 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
726a989a RB |
416 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
417 | true, GSI_SAME_STMT); | |
18d08014 | 418 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
419 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
420 | true, GSI_SAME_STMT); | |
777d77b3 MG |
421 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
422 | boolean_type_node, t2, t); | |
740bb6ad RG |
423 | t = canonicalize_cond_expr_cond (t); |
424 | if (!t) | |
425 | return false; | |
726a989a | 426 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
427 | update_stmt (inner_cond); |
428 | ||
429 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
430 | gimple_cond_set_condition_from_tree (outer_cond, |
431 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
432 | update_stmt (outer_cond); |
433 | ||
30c6ec2f JH |
434 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
435 | ||
18d08014 RG |
436 | if (dump_file) |
437 | { | |
438 | fprintf (dump_file, "optimizing double bit test to "); | |
ef6cb4c7 | 439 | print_generic_expr (dump_file, name1); |
18d08014 | 440 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); |
ef6cb4c7 | 441 | print_generic_expr (dump_file, bit1); |
18d08014 | 442 | fprintf (dump_file, ") | (1 << "); |
ef6cb4c7 | 443 | print_generic_expr (dump_file, bit2); |
18d08014 RG |
444 | fprintf (dump_file, ")\n"); |
445 | } | |
446 | ||
447 | return true; | |
448 | } | |
449 | ||
18d08014 RG |
450 | /* See if we have two bit tests of the same name in both tests. |
451 | In that case remove the outer test and change the inner one to | |
452 | test for name & (bits1 | bits2) != 0. */ | |
777d77b3 MG |
453 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
454 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
18d08014 | 455 | { |
726a989a | 456 | gimple_stmt_iterator gsi; |
18d08014 RG |
457 | tree t; |
458 | ||
459 | /* Find the common name which is bit-tested. */ | |
460 | if (name1 == name2) | |
461 | ; | |
462 | else if (bits1 == bits2) | |
463 | { | |
fab27f52 MM |
464 | std::swap (name2, bits2); |
465 | std::swap (name1, bits1); | |
18d08014 RG |
466 | } |
467 | else if (name1 == bits2) | |
fab27f52 | 468 | std::swap (name2, bits2); |
18d08014 | 469 | else if (bits1 == name2) |
fab27f52 | 470 | std::swap (name1, bits1); |
18d08014 RG |
471 | else |
472 | return false; | |
473 | ||
6e548df5 RG |
474 | /* As we strip non-widening conversions in finding a common |
475 | name that is tested make sure to end up with an integral | |
476 | type for building the bit operations. */ | |
477 | if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
478 | >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
479 | { | |
480 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
481 | name1 = fold_convert (TREE_TYPE (bits1), name1); | |
482 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
483 | bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
484 | } | |
485 | else | |
486 | { | |
487 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
488 | name1 = fold_convert (TREE_TYPE (bits2), name1); | |
489 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
490 | bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
491 | } | |
492 | ||
18d08014 | 493 | /* Do it. */ |
726a989a | 494 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 495 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); |
726a989a RB |
496 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
497 | true, GSI_SAME_STMT); | |
18d08014 | 498 | t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
499 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
500 | true, GSI_SAME_STMT); | |
777d77b3 | 501 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
726a989a | 502 | build_int_cst (TREE_TYPE (t), 0)); |
740bb6ad RG |
503 | t = canonicalize_cond_expr_cond (t); |
504 | if (!t) | |
505 | return false; | |
726a989a | 506 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
507 | update_stmt (inner_cond); |
508 | ||
509 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
510 | gimple_cond_set_condition_from_tree (outer_cond, |
511 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 | 512 | update_stmt (outer_cond); |
30c6ec2f | 513 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
18d08014 RG |
514 | |
515 | if (dump_file) | |
516 | { | |
517 | fprintf (dump_file, "optimizing bits or bits test to "); | |
ef6cb4c7 | 518 | print_generic_expr (dump_file, name1); |
18d08014 | 519 | fprintf (dump_file, " & T != 0\nwith temporary T = "); |
ef6cb4c7 | 520 | print_generic_expr (dump_file, bits1); |
18d08014 | 521 | fprintf (dump_file, " | "); |
ef6cb4c7 | 522 | print_generic_expr (dump_file, bits2); |
18d08014 RG |
523 | fprintf (dump_file, "\n"); |
524 | } | |
525 | ||
526 | return true; | |
527 | } | |
528 | ||
777d77b3 MG |
529 | /* See if we have two comparisons that we can merge into one. */ |
530 | else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
e89065a1 | 531 | && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
18d08014 | 532 | { |
18d08014 | 533 | tree t; |
777d77b3 MG |
534 | enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
535 | enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
536 | ||
537 | /* Invert comparisons if necessary (and possible). */ | |
538 | if (inner_inv) | |
539 | inner_cond_code = invert_tree_comparison (inner_cond_code, | |
1b457aa4 | 540 | HONOR_NANS (gimple_cond_lhs (inner_cond))); |
777d77b3 MG |
541 | if (inner_cond_code == ERROR_MARK) |
542 | return false; | |
543 | if (outer_inv) | |
544 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
1b457aa4 | 545 | HONOR_NANS (gimple_cond_lhs (outer_cond))); |
777d77b3 MG |
546 | if (outer_cond_code == ERROR_MARK) |
547 | return false; | |
548 | /* Don't return false so fast, try maybe_fold_or_comparisons? */ | |
18d08014 | 549 | |
777d77b3 MG |
550 | if (!(t = maybe_fold_and_comparisons (inner_cond_code, |
551 | gimple_cond_lhs (inner_cond), | |
552 | gimple_cond_rhs (inner_cond), | |
553 | outer_cond_code, | |
554 | gimple_cond_lhs (outer_cond), | |
555 | gimple_cond_rhs (outer_cond)))) | |
5d2a9da9 AP |
556 | { |
557 | tree t1, t2; | |
558 | gimple_stmt_iterator gsi; | |
f6e50a7d | 559 | if (!LOGICAL_OP_NON_SHORT_CIRCUIT || flag_sanitize_coverage) |
5d2a9da9 AP |
560 | return false; |
561 | /* Only do this optimization if the inner bb contains only the conditional. */ | |
562 | if (!gsi_one_before_end_p (gsi_start_nondebug_after_labels_bb (inner_cond_bb))) | |
563 | return false; | |
564 | t1 = fold_build2_loc (gimple_location (inner_cond), | |
565 | inner_cond_code, | |
566 | boolean_type_node, | |
567 | gimple_cond_lhs (inner_cond), | |
568 | gimple_cond_rhs (inner_cond)); | |
569 | t2 = fold_build2_loc (gimple_location (outer_cond), | |
570 | outer_cond_code, | |
571 | boolean_type_node, | |
572 | gimple_cond_lhs (outer_cond), | |
573 | gimple_cond_rhs (outer_cond)); | |
574 | t = fold_build2_loc (gimple_location (inner_cond), | |
575 | TRUTH_AND_EXPR, boolean_type_node, t1, t2); | |
576 | if (result_inv) | |
577 | { | |
578 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
579 | result_inv = false; | |
580 | } | |
581 | gsi = gsi_for_stmt (inner_cond); | |
582 | t = force_gimple_operand_gsi_1 (&gsi, t, is_gimple_condexpr, NULL, true, | |
583 | GSI_SAME_STMT); | |
584 | } | |
777d77b3 MG |
585 | if (result_inv) |
586 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
dc575233 RG |
587 | t = canonicalize_cond_expr_cond (t); |
588 | if (!t) | |
589 | return false; | |
726a989a | 590 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
591 | update_stmt (inner_cond); |
592 | ||
593 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
594 | gimple_cond_set_condition_from_tree (outer_cond, |
595 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 | 596 | update_stmt (outer_cond); |
30c6ec2f | 597 | update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); |
18d08014 RG |
598 | |
599 | if (dump_file) | |
600 | { | |
601 | fprintf (dump_file, "optimizing two comparisons to "); | |
ef6cb4c7 | 602 | print_generic_expr (dump_file, t); |
18d08014 RG |
603 | fprintf (dump_file, "\n"); |
604 | } | |
605 | ||
606 | return true; | |
607 | } | |
608 | ||
609 | return false; | |
610 | } | |
611 | ||
bf4787b2 JJ |
612 | /* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and |
613 | dispatch to the appropriate if-conversion helper for a particular | |
614 | set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. | |
615 | PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ | |
616 | ||
617 | static bool | |
618 | tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, | |
619 | basic_block then_bb, basic_block else_bb, | |
620 | basic_block phi_pred_bb) | |
621 | { | |
622 | /* The && form is characterized by a common else_bb with | |
623 | the two edges leading to it mergable. The latter is | |
624 | guaranteed by matching PHI arguments in the else_bb and | |
625 | the inner cond_bb having no side-effects. */ | |
626 | if (phi_pred_bb != else_bb | |
627 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
067339d2 | 628 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) |
bf4787b2 JJ |
629 | { |
630 | /* We have | |
631 | <outer_cond_bb> | |
632 | if (q) goto inner_cond_bb; else goto else_bb; | |
633 | <inner_cond_bb> | |
634 | if (p) goto ...; else goto else_bb; | |
635 | ... | |
636 | <else_bb> | |
637 | ... | |
638 | */ | |
639 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, | |
640 | false); | |
641 | } | |
642 | ||
643 | /* And a version where the outer condition is negated. */ | |
644 | if (phi_pred_bb != else_bb | |
645 | && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
067339d2 | 646 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb)) |
bf4787b2 JJ |
647 | { |
648 | /* We have | |
649 | <outer_cond_bb> | |
650 | if (q) goto else_bb; else goto inner_cond_bb; | |
651 | <inner_cond_bb> | |
652 | if (p) goto ...; else goto else_bb; | |
653 | ... | |
654 | <else_bb> | |
655 | ... | |
656 | */ | |
657 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
658 | false); | |
659 | } | |
660 | ||
661 | /* The || form is characterized by a common then_bb with the | |
662 | two edges leading to it mergable. The latter is guaranteed | |
663 | by matching PHI arguments in the then_bb and the inner cond_bb | |
664 | having no side-effects. */ | |
665 | if (phi_pred_bb != then_bb | |
666 | && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
067339d2 | 667 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) |
bf4787b2 JJ |
668 | { |
669 | /* We have | |
670 | <outer_cond_bb> | |
671 | if (q) goto then_bb; else goto inner_cond_bb; | |
672 | <inner_cond_bb> | |
673 | if (q) goto then_bb; else goto ...; | |
674 | <then_bb> | |
675 | ... | |
676 | */ | |
677 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, | |
678 | true); | |
679 | } | |
680 | ||
681 | /* And a version where the outer condition is negated. */ | |
682 | if (phi_pred_bb != then_bb | |
683 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
067339d2 | 684 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb)) |
bf4787b2 JJ |
685 | { |
686 | /* We have | |
687 | <outer_cond_bb> | |
688 | if (q) goto inner_cond_bb; else goto then_bb; | |
689 | <inner_cond_bb> | |
690 | if (q) goto then_bb; else goto ...; | |
691 | <then_bb> | |
692 | ... | |
693 | */ | |
694 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
695 | true); | |
696 | } | |
697 | ||
698 | return false; | |
699 | } | |
700 | ||
18d08014 RG |
701 | /* Recognize a CFG pattern and dispatch to the appropriate |
702 | if-conversion helper. We start with BB as the innermost | |
703 | worker basic-block. Returns true if a transformation was done. */ | |
704 | ||
705 | static bool | |
706 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
707 | { | |
708 | basic_block then_bb = NULL, else_bb = NULL; | |
709 | ||
710 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
711 | return false; | |
712 | ||
713 | /* Recognize && and || of two conditions with a common | |
714 | then/else block which entry edges we can merge. That is: | |
715 | if (a || b) | |
716 | ; | |
717 | and | |
718 | if (a && b) | |
719 | ; | |
720 | This requires a single predecessor of the inner cond_bb. */ | |
067339d2 AO |
721 | if (single_pred_p (inner_cond_bb) |
722 | && bb_no_side_effects_p (inner_cond_bb)) | |
18d08014 RG |
723 | { |
724 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
725 | ||
bf4787b2 JJ |
726 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, |
727 | then_bb, else_bb, inner_cond_bb)) | |
728 | return true; | |
777d77b3 | 729 | |
bf4787b2 | 730 | if (forwarder_block_to (else_bb, then_bb)) |
777d77b3 | 731 | { |
bf4787b2 JJ |
732 | /* Other possibilities for the && form, if else_bb is |
733 | empty forwarder block to then_bb. Compared to the above simpler | |
734 | forms this can be treated as if then_bb and else_bb were swapped, | |
735 | and the corresponding inner_cond_bb not inverted because of that. | |
736 | For same_phi_args_p we look at equality of arguments between | |
737 | edge from outer_cond_bb and the forwarder block. */ | |
738 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
739 | then_bb, else_bb)) | |
740 | return true; | |
18d08014 | 741 | } |
bf4787b2 | 742 | else if (forwarder_block_to (then_bb, else_bb)) |
777d77b3 | 743 | { |
bf4787b2 JJ |
744 | /* Other possibilities for the || form, if then_bb is |
745 | empty forwarder block to else_bb. Compared to the above simpler | |
746 | forms this can be treated as if then_bb and else_bb were swapped, | |
747 | and the corresponding inner_cond_bb not inverted because of that. | |
748 | For same_phi_args_p we look at equality of arguments between | |
749 | edge from outer_cond_bb and the forwarder block. */ | |
750 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
751 | then_bb, then_bb)) | |
752 | return true; | |
18d08014 RG |
753 | } |
754 | } | |
755 | ||
756 | return false; | |
757 | } | |
758 | ||
759 | /* Main entry for the tree if-conversion pass. */ | |
760 | ||
be55bfe6 TS |
761 | namespace { |
762 | ||
763 | const pass_data pass_data_tree_ifcombine = | |
764 | { | |
765 | GIMPLE_PASS, /* type */ | |
766 | "ifcombine", /* name */ | |
767 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
768 | TV_TREE_IFCOMBINE, /* tv_id */ |
769 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
770 | 0, /* properties_provided */ | |
771 | 0, /* properties_destroyed */ | |
772 | 0, /* todo_flags_start */ | |
3bea341f | 773 | TODO_update_ssa, /* todo_flags_finish */ |
be55bfe6 TS |
774 | }; |
775 | ||
776 | class pass_tree_ifcombine : public gimple_opt_pass | |
777 | { | |
778 | public: | |
779 | pass_tree_ifcombine (gcc::context *ctxt) | |
780 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
781 | {} | |
782 | ||
783 | /* opt_pass methods: */ | |
784 | virtual unsigned int execute (function *); | |
785 | ||
786 | }; // class pass_tree_ifcombine | |
787 | ||
788 | unsigned int | |
789 | pass_tree_ifcombine::execute (function *fun) | |
18d08014 RG |
790 | { |
791 | basic_block *bbs; | |
792 | bool cfg_changed = false; | |
793 | int i; | |
794 | ||
3d9c733e | 795 | bbs = single_pred_before_succ_order (); |
6c66f733 | 796 | calculate_dominance_info (CDI_DOMINATORS); |
18d08014 | 797 | |
5d2a9da9 AP |
798 | /* Search every basic block for COND_EXPR we may be able to optimize. |
799 | ||
800 | We walk the blocks in order that guarantees that a block with | |
801 | a single predecessor is processed after the predecessor. | |
802 | This ensures that we collapse outter ifs before visiting the | |
803 | inner ones, and also that we do not try to visit a removed | |
804 | block. This is opposite of PHI-OPT, because we cascade the | |
805 | combining rather than cascading PHIs. */ | |
be55bfe6 | 806 | for (i = n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) |
18d08014 RG |
807 | { |
808 | basic_block bb = bbs[i]; | |
355fe088 | 809 | gimple *stmt = last_stmt (bb); |
18d08014 RG |
810 | |
811 | if (stmt | |
726a989a | 812 | && gimple_code (stmt) == GIMPLE_COND) |
8bb8e838 RB |
813 | if (tree_ssa_ifcombine_bb (bb)) |
814 | { | |
815 | /* Clear range info from all stmts in BB which is now executed | |
816 | conditional on a always true/false condition. */ | |
6ea2f74c | 817 | reset_flow_sensitive_info_in_bb (bb); |
8bb8e838 RB |
818 | cfg_changed |= true; |
819 | } | |
18d08014 RG |
820 | } |
821 | ||
822 | free (bbs); | |
823 | ||
824 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
825 | } | |
826 | ||
27a4cd48 DM |
827 | } // anon namespace |
828 | ||
829 | gimple_opt_pass * | |
830 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
831 | { | |
832 | return new pass_tree_ifcombine (ctxt); | |
833 | } |