]>
Commit | Line | Data |
---|---|---|
18d08014 | 1 | /* Combining of if-expressions on trees. |
5624e564 | 2 | Copyright (C) 2007-2015 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" | |
30 | #include "tm_p.h" | |
c7131fb2 | 31 | #include "ssa.h" |
957060b5 | 32 | #include "tree-pretty-print.h" |
5d2a9da9 AP |
33 | /* rtl is needed only because arm back-end requires it for |
34 | BRANCH_COST. */ | |
40e23961 | 35 | #include "alias.h" |
40e23961 | 36 | #include "fold-const.h" |
d8a2d370 | 37 | #include "stor-layout.h" |
60393bbc | 38 | #include "cfganal.h" |
2fb9a547 AM |
39 | #include "internal-fn.h" |
40 | #include "gimple-fold.h" | |
5be5c238 | 41 | #include "gimple-iterator.h" |
18f429e2 | 42 | #include "gimplify-me.h" |
442b4905 | 43 | #include "tree-cfg.h" |
18d08014 | 44 | |
5d2a9da9 AP |
45 | #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT |
46 | #define LOGICAL_OP_NON_SHORT_CIRCUIT \ | |
47 | (BRANCH_COST (optimize_function_for_speed_p (cfun), \ | |
48 | false) >= 2) | |
49 | #endif | |
50 | ||
18d08014 RG |
51 | /* This pass combines COND_EXPRs to simplify control flow. It |
52 | currently recognizes bit tests and comparisons in chains that | |
53 | represent logical and or logical or of two COND_EXPRs. | |
54 | ||
55 | It does so by walking basic blocks in a approximate reverse | |
56 | post-dominator order and trying to match CFG patterns that | |
57 | represent logical and or logical or of two COND_EXPRs. | |
58 | Transformations are done if the COND_EXPR conditions match | |
59 | either | |
60 | ||
61 | 1. two single bit tests X & (1 << Yn) (for logical and) | |
62 | ||
63 | 2. two bit tests X & Yn (for logical or) | |
64 | ||
65 | 3. two comparisons X OPn Y (for logical or) | |
66 | ||
67 | To simplify this pass, removing basic blocks and dead code | |
68 | is left to CFG cleanup and DCE. */ | |
69 | ||
70 | ||
71 | /* Recognize a if-then-else CFG pattern starting to match with the | |
72 | COND_BB basic-block containing the COND_EXPR. The recognized | |
73 | then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
74 | *THEN_BB and/or *ELSE_BB are already set, they are required to | |
75 | match the then and else basic-blocks to make the pattern match. | |
76 | Returns true if the pattern matched, false otherwise. */ | |
77 | ||
78 | static bool | |
79 | recognize_if_then_else (basic_block cond_bb, | |
80 | basic_block *then_bb, basic_block *else_bb) | |
81 | { | |
82 | edge t, e; | |
83 | ||
84 | if (EDGE_COUNT (cond_bb->succs) != 2) | |
85 | return false; | |
86 | ||
87 | /* Find the then/else edges. */ | |
88 | t = EDGE_SUCC (cond_bb, 0); | |
89 | e = EDGE_SUCC (cond_bb, 1); | |
90 | if (!(t->flags & EDGE_TRUE_VALUE)) | |
6b4db501 | 91 | std::swap (t, e); |
18d08014 RG |
92 | if (!(t->flags & EDGE_TRUE_VALUE) |
93 | || !(e->flags & EDGE_FALSE_VALUE)) | |
94 | return false; | |
95 | ||
96 | /* Check if the edge destinations point to the required block. */ | |
97 | if (*then_bb | |
98 | && t->dest != *then_bb) | |
99 | return false; | |
100 | if (*else_bb | |
101 | && e->dest != *else_bb) | |
102 | return false; | |
103 | ||
104 | if (!*then_bb) | |
105 | *then_bb = t->dest; | |
106 | if (!*else_bb) | |
107 | *else_bb = e->dest; | |
108 | ||
109 | return true; | |
110 | } | |
111 | ||
112 | /* Verify if the basic block BB does not have side-effects. Return | |
113 | true in this case, else false. */ | |
114 | ||
115 | static bool | |
116 | bb_no_side_effects_p (basic_block bb) | |
117 | { | |
726a989a | 118 | gimple_stmt_iterator gsi; |
18d08014 | 119 | |
726a989a | 120 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
18d08014 | 121 | { |
355fe088 | 122 | gimple *stmt = gsi_stmt (gsi); |
18d08014 | 123 | |
597c6315 RB |
124 | if (is_gimple_debug (stmt)) |
125 | continue; | |
126 | ||
179184e3 | 127 | if (gimple_has_side_effects (stmt) |
597c6315 | 128 | || gimple_could_trap_p (stmt) |
5006671f | 129 | || gimple_vuse (stmt)) |
18d08014 RG |
130 | return false; |
131 | } | |
132 | ||
133 | return true; | |
134 | } | |
135 | ||
bf4787b2 JJ |
136 | /* Return true if BB is an empty forwarder block to TO_BB. */ |
137 | ||
138 | static bool | |
139 | forwarder_block_to (basic_block bb, basic_block to_bb) | |
140 | { | |
141 | return empty_block_p (bb) | |
142 | && single_succ_p (bb) | |
143 | && single_succ (bb) == to_bb; | |
144 | } | |
145 | ||
18d08014 RG |
146 | /* Verify if all PHI node arguments in DEST for edges from BB1 or |
147 | BB2 to DEST are the same. This makes the CFG merge point | |
148 | free from side-effects. Return true in this case, else false. */ | |
149 | ||
150 | static bool | |
151 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
152 | { | |
153 | edge e1 = find_edge (bb1, dest); | |
154 | edge e2 = find_edge (bb2, dest); | |
538dd0b7 DM |
155 | gphi_iterator gsi; |
156 | gphi *phi; | |
18d08014 | 157 | |
726a989a RB |
158 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
159 | { | |
538dd0b7 | 160 | phi = gsi.phi (); |
726a989a RB |
161 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), |
162 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
163 | return false; | |
164 | } | |
18d08014 RG |
165 | |
166 | return true; | |
167 | } | |
168 | ||
d7b339dd RG |
169 | /* Return the best representative SSA name for CANDIDATE which is used |
170 | in a bit test. */ | |
171 | ||
172 | static tree | |
173 | get_name_for_bit_test (tree candidate) | |
174 | { | |
175 | /* Skip single-use names in favor of using the name from a | |
176 | non-widening conversion definition. */ | |
177 | if (TREE_CODE (candidate) == SSA_NAME | |
178 | && has_single_use (candidate)) | |
179 | { | |
355fe088 | 180 | gimple *def_stmt = SSA_NAME_DEF_STMT (candidate); |
726a989a | 181 | if (is_gimple_assign (def_stmt) |
a6450905 | 182 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
d7b339dd | 183 | { |
726a989a RB |
184 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
185 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
186 | return gimple_assign_rhs1 (def_stmt); | |
d7b339dd RG |
187 | } |
188 | } | |
189 | ||
190 | return candidate; | |
191 | } | |
192 | ||
726a989a | 193 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
18d08014 | 194 | statements. Store the name being tested in *NAME and the bit |
726a989a | 195 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
18d08014 RG |
196 | Returns true if the pattern matched, false otherwise. */ |
197 | ||
198 | static bool | |
538dd0b7 | 199 | recognize_single_bit_test (gcond *cond, tree *name, tree *bit, bool inv) |
18d08014 | 200 | { |
355fe088 | 201 | gimple *stmt; |
18d08014 RG |
202 | |
203 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 204 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
205 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
206 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 207 | return false; |
726a989a RB |
208 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
209 | if (!is_gimple_assign (stmt)) | |
18d08014 | 210 | return false; |
18d08014 RG |
211 | |
212 | /* Look at which bit is tested. One form to recognize is | |
213 | D.1985_5 = state_3(D) >> control1_4(D); | |
214 | D.1986_6 = (int) D.1985_5; | |
215 | D.1987_7 = op0 & 1; | |
216 | if (D.1987_7 != 0) */ | |
726a989a RB |
217 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
218 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
219 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
18d08014 | 220 | { |
726a989a | 221 | tree orig_name = gimple_assign_rhs1 (stmt); |
b0569227 RG |
222 | |
223 | /* Look through copies and conversions to eventually | |
224 | find the stmt that computes the shift. */ | |
726a989a RB |
225 | stmt = SSA_NAME_DEF_STMT (orig_name); |
226 | ||
227 | while (is_gimple_assign (stmt) | |
a6450905 RG |
228 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
229 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
14e000de JJ |
230 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))) |
231 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
a6450905 RG |
232 | || gimple_assign_ssa_name_copy_p (stmt))) |
233 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
18d08014 | 234 | |
b0569227 | 235 | /* If we found such, decompose it. */ |
726a989a RB |
236 | if (is_gimple_assign (stmt) |
237 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
18d08014 RG |
238 | { |
239 | /* op0 & (1 << op1) */ | |
726a989a RB |
240 | *bit = gimple_assign_rhs2 (stmt); |
241 | *name = gimple_assign_rhs1 (stmt); | |
18d08014 RG |
242 | } |
243 | else | |
244 | { | |
245 | /* t & 1 */ | |
b0569227 | 246 | *bit = integer_zero_node; |
d7b339dd | 247 | *name = get_name_for_bit_test (orig_name); |
18d08014 RG |
248 | } |
249 | ||
250 | return true; | |
251 | } | |
252 | ||
253 | /* Another form is | |
254 | D.1987_7 = op0 & (1 << CST) | |
255 | if (D.1987_7 != 0) */ | |
726a989a RB |
256 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
257 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
258 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
18d08014 | 259 | { |
726a989a | 260 | *name = gimple_assign_rhs1 (stmt); |
18d08014 | 261 | *bit = build_int_cst (integer_type_node, |
726a989a | 262 | tree_log2 (gimple_assign_rhs2 (stmt))); |
18d08014 RG |
263 | return true; |
264 | } | |
265 | ||
266 | /* Another form is | |
267 | D.1986_6 = 1 << control1_4(D) | |
268 | D.1987_7 = op0 & D.1986_6 | |
269 | if (D.1987_7 != 0) */ | |
726a989a RB |
270 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
271 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
272 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
18d08014 | 273 | { |
355fe088 | 274 | gimple *tmp; |
18d08014 RG |
275 | |
276 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
277 | specifying expression. */ | |
726a989a RB |
278 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
279 | if (is_gimple_assign (tmp) | |
280 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
281 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 282 | { |
726a989a RB |
283 | *name = gimple_assign_rhs2 (stmt); |
284 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
285 | return true; |
286 | } | |
287 | ||
726a989a RB |
288 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
289 | if (is_gimple_assign (tmp) | |
290 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
291 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 292 | { |
726a989a RB |
293 | *name = gimple_assign_rhs1 (stmt); |
294 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
295 | return true; |
296 | } | |
297 | } | |
298 | ||
299 | return false; | |
300 | } | |
301 | ||
726a989a | 302 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
18d08014 RG |
303 | statements. Store the name being tested in *NAME and the bits |
304 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
305 | Returns true if the pattern matched, false otherwise. */ | |
306 | ||
307 | static bool | |
538dd0b7 | 308 | recognize_bits_test (gcond *cond, tree *name, tree *bits, bool inv) |
18d08014 | 309 | { |
355fe088 | 310 | gimple *stmt; |
18d08014 RG |
311 | |
312 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 313 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
314 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
315 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 316 | return false; |
726a989a RB |
317 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
318 | if (!is_gimple_assign (stmt) | |
319 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
18d08014 RG |
320 | return false; |
321 | ||
726a989a RB |
322 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
323 | *bits = gimple_assign_rhs2 (stmt); | |
18d08014 RG |
324 | |
325 | return true; | |
326 | } | |
327 | ||
328 | /* If-convert on a and pattern with a common else block. The inner | |
329 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
777d77b3 MG |
330 | inner_inv, outer_inv and result_inv indicate whether the conditions |
331 | are inverted. | |
18d08014 RG |
332 | Returns true if the edges to the common else basic-block were merged. */ |
333 | ||
334 | static bool | |
777d77b3 MG |
335 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
336 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
18d08014 | 337 | { |
726a989a | 338 | gimple_stmt_iterator gsi; |
355fe088 | 339 | gimple *inner_stmt, *outer_stmt; |
538dd0b7 | 340 | gcond *inner_cond, *outer_cond; |
777d77b3 | 341 | tree name1, name2, bit1, bit2, bits1, bits2; |
18d08014 | 342 | |
538dd0b7 DM |
343 | inner_stmt = last_stmt (inner_cond_bb); |
344 | if (!inner_stmt | |
345 | || gimple_code (inner_stmt) != GIMPLE_COND) | |
18d08014 | 346 | return false; |
538dd0b7 | 347 | inner_cond = as_a <gcond *> (inner_stmt); |
18d08014 | 348 | |
538dd0b7 DM |
349 | outer_stmt = last_stmt (outer_cond_bb); |
350 | if (!outer_stmt | |
351 | || gimple_code (outer_stmt) != GIMPLE_COND) | |
18d08014 | 352 | return false; |
538dd0b7 | 353 | outer_cond = as_a <gcond *> (outer_stmt); |
18d08014 RG |
354 | |
355 | /* See if we test a single bit of the same name in both tests. In | |
356 | that case remove the outer test, merging both else edges, | |
357 | and change the inner one to test for | |
358 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
777d77b3 MG |
359 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
360 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
18d08014 RG |
361 | && name1 == name2) |
362 | { | |
363 | tree t, t2; | |
364 | ||
365 | /* Do it. */ | |
726a989a | 366 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 367 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 368 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
18d08014 | 369 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 370 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
18d08014 | 371 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
726a989a RB |
372 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
373 | true, GSI_SAME_STMT); | |
18d08014 | 374 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
375 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
376 | true, GSI_SAME_STMT); | |
777d77b3 MG |
377 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
378 | boolean_type_node, t2, t); | |
740bb6ad RG |
379 | t = canonicalize_cond_expr_cond (t); |
380 | if (!t) | |
381 | return false; | |
726a989a | 382 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
383 | update_stmt (inner_cond); |
384 | ||
385 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
386 | gimple_cond_set_condition_from_tree (outer_cond, |
387 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
388 | update_stmt (outer_cond); |
389 | ||
390 | if (dump_file) | |
391 | { | |
392 | fprintf (dump_file, "optimizing double bit test to "); | |
393 | print_generic_expr (dump_file, name1, 0); | |
394 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); | |
395 | print_generic_expr (dump_file, bit1, 0); | |
396 | fprintf (dump_file, ") | (1 << "); | |
397 | print_generic_expr (dump_file, bit2, 0); | |
398 | fprintf (dump_file, ")\n"); | |
399 | } | |
400 | ||
401 | return true; | |
402 | } | |
403 | ||
18d08014 RG |
404 | /* See if we have two bit tests of the same name in both tests. |
405 | In that case remove the outer test and change the inner one to | |
406 | test for name & (bits1 | bits2) != 0. */ | |
777d77b3 MG |
407 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
408 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
18d08014 | 409 | { |
726a989a | 410 | gimple_stmt_iterator gsi; |
18d08014 RG |
411 | tree t; |
412 | ||
413 | /* Find the common name which is bit-tested. */ | |
414 | if (name1 == name2) | |
415 | ; | |
416 | else if (bits1 == bits2) | |
417 | { | |
fab27f52 MM |
418 | std::swap (name2, bits2); |
419 | std::swap (name1, bits1); | |
18d08014 RG |
420 | } |
421 | else if (name1 == bits2) | |
fab27f52 | 422 | std::swap (name2, bits2); |
18d08014 | 423 | else if (bits1 == name2) |
fab27f52 | 424 | std::swap (name1, bits1); |
18d08014 RG |
425 | else |
426 | return false; | |
427 | ||
6e548df5 RG |
428 | /* As we strip non-widening conversions in finding a common |
429 | name that is tested make sure to end up with an integral | |
430 | type for building the bit operations. */ | |
431 | if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
432 | >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
433 | { | |
434 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
435 | name1 = fold_convert (TREE_TYPE (bits1), name1); | |
436 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
437 | bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
438 | } | |
439 | else | |
440 | { | |
441 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
442 | name1 = fold_convert (TREE_TYPE (bits2), name1); | |
443 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
444 | bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
445 | } | |
446 | ||
18d08014 | 447 | /* Do it. */ |
726a989a | 448 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 449 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); |
726a989a RB |
450 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
451 | true, GSI_SAME_STMT); | |
18d08014 | 452 | t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
453 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
454 | true, GSI_SAME_STMT); | |
777d77b3 | 455 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
726a989a | 456 | build_int_cst (TREE_TYPE (t), 0)); |
740bb6ad RG |
457 | t = canonicalize_cond_expr_cond (t); |
458 | if (!t) | |
459 | return false; | |
726a989a | 460 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
461 | update_stmt (inner_cond); |
462 | ||
463 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
464 | gimple_cond_set_condition_from_tree (outer_cond, |
465 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
466 | update_stmt (outer_cond); |
467 | ||
468 | if (dump_file) | |
469 | { | |
470 | fprintf (dump_file, "optimizing bits or bits test to "); | |
471 | print_generic_expr (dump_file, name1, 0); | |
472 | fprintf (dump_file, " & T != 0\nwith temporary T = "); | |
473 | print_generic_expr (dump_file, bits1, 0); | |
474 | fprintf (dump_file, " | "); | |
475 | print_generic_expr (dump_file, bits2, 0); | |
476 | fprintf (dump_file, "\n"); | |
477 | } | |
478 | ||
479 | return true; | |
480 | } | |
481 | ||
777d77b3 MG |
482 | /* See if we have two comparisons that we can merge into one. */ |
483 | else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
e89065a1 | 484 | && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
18d08014 | 485 | { |
18d08014 | 486 | tree t; |
777d77b3 MG |
487 | enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
488 | enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
489 | ||
490 | /* Invert comparisons if necessary (and possible). */ | |
491 | if (inner_inv) | |
492 | inner_cond_code = invert_tree_comparison (inner_cond_code, | |
1b457aa4 | 493 | HONOR_NANS (gimple_cond_lhs (inner_cond))); |
777d77b3 MG |
494 | if (inner_cond_code == ERROR_MARK) |
495 | return false; | |
496 | if (outer_inv) | |
497 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
1b457aa4 | 498 | HONOR_NANS (gimple_cond_lhs (outer_cond))); |
777d77b3 MG |
499 | if (outer_cond_code == ERROR_MARK) |
500 | return false; | |
501 | /* Don't return false so fast, try maybe_fold_or_comparisons? */ | |
18d08014 | 502 | |
777d77b3 MG |
503 | if (!(t = maybe_fold_and_comparisons (inner_cond_code, |
504 | gimple_cond_lhs (inner_cond), | |
505 | gimple_cond_rhs (inner_cond), | |
506 | outer_cond_code, | |
507 | gimple_cond_lhs (outer_cond), | |
508 | gimple_cond_rhs (outer_cond)))) | |
5d2a9da9 AP |
509 | { |
510 | tree t1, t2; | |
511 | gimple_stmt_iterator gsi; | |
512 | if (!LOGICAL_OP_NON_SHORT_CIRCUIT) | |
513 | return false; | |
514 | /* Only do this optimization if the inner bb contains only the conditional. */ | |
515 | if (!gsi_one_before_end_p (gsi_start_nondebug_after_labels_bb (inner_cond_bb))) | |
516 | return false; | |
517 | t1 = fold_build2_loc (gimple_location (inner_cond), | |
518 | inner_cond_code, | |
519 | boolean_type_node, | |
520 | gimple_cond_lhs (inner_cond), | |
521 | gimple_cond_rhs (inner_cond)); | |
522 | t2 = fold_build2_loc (gimple_location (outer_cond), | |
523 | outer_cond_code, | |
524 | boolean_type_node, | |
525 | gimple_cond_lhs (outer_cond), | |
526 | gimple_cond_rhs (outer_cond)); | |
527 | t = fold_build2_loc (gimple_location (inner_cond), | |
528 | TRUTH_AND_EXPR, boolean_type_node, t1, t2); | |
529 | if (result_inv) | |
530 | { | |
531 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
532 | result_inv = false; | |
533 | } | |
534 | gsi = gsi_for_stmt (inner_cond); | |
535 | t = force_gimple_operand_gsi_1 (&gsi, t, is_gimple_condexpr, NULL, true, | |
536 | GSI_SAME_STMT); | |
537 | } | |
777d77b3 MG |
538 | if (result_inv) |
539 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
dc575233 RG |
540 | t = canonicalize_cond_expr_cond (t); |
541 | if (!t) | |
542 | return false; | |
726a989a | 543 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
544 | update_stmt (inner_cond); |
545 | ||
546 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
547 | gimple_cond_set_condition_from_tree (outer_cond, |
548 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
549 | update_stmt (outer_cond); |
550 | ||
551 | if (dump_file) | |
552 | { | |
553 | fprintf (dump_file, "optimizing two comparisons to "); | |
554 | print_generic_expr (dump_file, t, 0); | |
555 | fprintf (dump_file, "\n"); | |
556 | } | |
557 | ||
558 | return true; | |
559 | } | |
560 | ||
561 | return false; | |
562 | } | |
563 | ||
bf4787b2 JJ |
564 | /* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and |
565 | dispatch to the appropriate if-conversion helper for a particular | |
566 | set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. | |
567 | PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ | |
568 | ||
569 | static bool | |
570 | tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, | |
571 | basic_block then_bb, basic_block else_bb, | |
572 | basic_block phi_pred_bb) | |
573 | { | |
574 | /* The && form is characterized by a common else_bb with | |
575 | the two edges leading to it mergable. The latter is | |
576 | guaranteed by matching PHI arguments in the else_bb and | |
577 | the inner cond_bb having no side-effects. */ | |
578 | if (phi_pred_bb != else_bb | |
579 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
580 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) | |
581 | && bb_no_side_effects_p (inner_cond_bb)) | |
582 | { | |
583 | /* We have | |
584 | <outer_cond_bb> | |
585 | if (q) goto inner_cond_bb; else goto else_bb; | |
586 | <inner_cond_bb> | |
587 | if (p) goto ...; else goto else_bb; | |
588 | ... | |
589 | <else_bb> | |
590 | ... | |
591 | */ | |
592 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, | |
593 | false); | |
594 | } | |
595 | ||
596 | /* And a version where the outer condition is negated. */ | |
597 | if (phi_pred_bb != else_bb | |
598 | && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
599 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) | |
600 | && bb_no_side_effects_p (inner_cond_bb)) | |
601 | { | |
602 | /* We have | |
603 | <outer_cond_bb> | |
604 | if (q) goto else_bb; else goto inner_cond_bb; | |
605 | <inner_cond_bb> | |
606 | if (p) goto ...; else goto else_bb; | |
607 | ... | |
608 | <else_bb> | |
609 | ... | |
610 | */ | |
611 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
612 | false); | |
613 | } | |
614 | ||
615 | /* The || form is characterized by a common then_bb with the | |
616 | two edges leading to it mergable. The latter is guaranteed | |
617 | by matching PHI arguments in the then_bb and the inner cond_bb | |
618 | having no side-effects. */ | |
619 | if (phi_pred_bb != then_bb | |
620 | && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
621 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) | |
622 | && bb_no_side_effects_p (inner_cond_bb)) | |
623 | { | |
624 | /* We have | |
625 | <outer_cond_bb> | |
626 | if (q) goto then_bb; else goto inner_cond_bb; | |
627 | <inner_cond_bb> | |
628 | if (q) goto then_bb; else goto ...; | |
629 | <then_bb> | |
630 | ... | |
631 | */ | |
632 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, | |
633 | true); | |
634 | } | |
635 | ||
636 | /* And a version where the outer condition is negated. */ | |
637 | if (phi_pred_bb != then_bb | |
638 | && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
639 | && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) | |
640 | && bb_no_side_effects_p (inner_cond_bb)) | |
641 | { | |
642 | /* We have | |
643 | <outer_cond_bb> | |
644 | if (q) goto inner_cond_bb; else goto then_bb; | |
645 | <inner_cond_bb> | |
646 | if (q) goto then_bb; else goto ...; | |
647 | <then_bb> | |
648 | ... | |
649 | */ | |
650 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
651 | true); | |
652 | } | |
653 | ||
654 | return false; | |
655 | } | |
656 | ||
18d08014 RG |
657 | /* Recognize a CFG pattern and dispatch to the appropriate |
658 | if-conversion helper. We start with BB as the innermost | |
659 | worker basic-block. Returns true if a transformation was done. */ | |
660 | ||
661 | static bool | |
662 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
663 | { | |
664 | basic_block then_bb = NULL, else_bb = NULL; | |
665 | ||
666 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
667 | return false; | |
668 | ||
669 | /* Recognize && and || of two conditions with a common | |
670 | then/else block which entry edges we can merge. That is: | |
671 | if (a || b) | |
672 | ; | |
673 | and | |
674 | if (a && b) | |
675 | ; | |
676 | This requires a single predecessor of the inner cond_bb. */ | |
677 | if (single_pred_p (inner_cond_bb)) | |
678 | { | |
679 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
680 | ||
bf4787b2 JJ |
681 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, |
682 | then_bb, else_bb, inner_cond_bb)) | |
683 | return true; | |
777d77b3 | 684 | |
bf4787b2 | 685 | if (forwarder_block_to (else_bb, then_bb)) |
777d77b3 | 686 | { |
bf4787b2 JJ |
687 | /* Other possibilities for the && form, if else_bb is |
688 | empty forwarder block to then_bb. Compared to the above simpler | |
689 | forms this can be treated as if then_bb and else_bb were swapped, | |
690 | and the corresponding inner_cond_bb not inverted because of that. | |
691 | For same_phi_args_p we look at equality of arguments between | |
692 | edge from outer_cond_bb and the forwarder block. */ | |
693 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
694 | then_bb, else_bb)) | |
695 | return true; | |
18d08014 | 696 | } |
bf4787b2 | 697 | else if (forwarder_block_to (then_bb, else_bb)) |
777d77b3 | 698 | { |
bf4787b2 JJ |
699 | /* Other possibilities for the || form, if then_bb is |
700 | empty forwarder block to else_bb. Compared to the above simpler | |
701 | forms this can be treated as if then_bb and else_bb were swapped, | |
702 | and the corresponding inner_cond_bb not inverted because of that. | |
703 | For same_phi_args_p we look at equality of arguments between | |
704 | edge from outer_cond_bb and the forwarder block. */ | |
705 | if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, | |
706 | then_bb, then_bb)) | |
707 | return true; | |
18d08014 RG |
708 | } |
709 | } | |
710 | ||
711 | return false; | |
712 | } | |
713 | ||
714 | /* Main entry for the tree if-conversion pass. */ | |
715 | ||
be55bfe6 TS |
716 | namespace { |
717 | ||
718 | const pass_data pass_data_tree_ifcombine = | |
719 | { | |
720 | GIMPLE_PASS, /* type */ | |
721 | "ifcombine", /* name */ | |
722 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
723 | TV_TREE_IFCOMBINE, /* tv_id */ |
724 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
725 | 0, /* properties_provided */ | |
726 | 0, /* properties_destroyed */ | |
727 | 0, /* todo_flags_start */ | |
3bea341f | 728 | TODO_update_ssa, /* todo_flags_finish */ |
be55bfe6 TS |
729 | }; |
730 | ||
731 | class pass_tree_ifcombine : public gimple_opt_pass | |
732 | { | |
733 | public: | |
734 | pass_tree_ifcombine (gcc::context *ctxt) | |
735 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
736 | {} | |
737 | ||
738 | /* opt_pass methods: */ | |
739 | virtual unsigned int execute (function *); | |
740 | ||
741 | }; // class pass_tree_ifcombine | |
742 | ||
743 | unsigned int | |
744 | pass_tree_ifcombine::execute (function *fun) | |
18d08014 RG |
745 | { |
746 | basic_block *bbs; | |
747 | bool cfg_changed = false; | |
748 | int i; | |
749 | ||
3d9c733e | 750 | bbs = single_pred_before_succ_order (); |
6c66f733 | 751 | calculate_dominance_info (CDI_DOMINATORS); |
18d08014 | 752 | |
5d2a9da9 AP |
753 | /* Search every basic block for COND_EXPR we may be able to optimize. |
754 | ||
755 | We walk the blocks in order that guarantees that a block with | |
756 | a single predecessor is processed after the predecessor. | |
757 | This ensures that we collapse outter ifs before visiting the | |
758 | inner ones, and also that we do not try to visit a removed | |
759 | block. This is opposite of PHI-OPT, because we cascade the | |
760 | combining rather than cascading PHIs. */ | |
be55bfe6 | 761 | for (i = n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) |
18d08014 RG |
762 | { |
763 | basic_block bb = bbs[i]; | |
355fe088 | 764 | gimple *stmt = last_stmt (bb); |
18d08014 RG |
765 | |
766 | if (stmt | |
726a989a | 767 | && gimple_code (stmt) == GIMPLE_COND) |
8bb8e838 RB |
768 | if (tree_ssa_ifcombine_bb (bb)) |
769 | { | |
770 | /* Clear range info from all stmts in BB which is now executed | |
771 | conditional on a always true/false condition. */ | |
6ea2f74c | 772 | reset_flow_sensitive_info_in_bb (bb); |
8bb8e838 RB |
773 | cfg_changed |= true; |
774 | } | |
18d08014 RG |
775 | } |
776 | ||
777 | free (bbs); | |
778 | ||
779 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
780 | } | |
781 | ||
27a4cd48 DM |
782 | } // anon namespace |
783 | ||
784 | gimple_opt_pass * | |
785 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
786 | { | |
787 | return new pass_tree_ifcombine (ctxt); | |
788 | } |