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18d08014 | 1 | /* Combining of if-expressions on trees. |
23a5b65a | 2 | Copyright (C) 2007-2014 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" | |
24 | #include "tm.h" | |
5d2a9da9 AP |
25 | /* rtl is needed only because arm back-end requires it for |
26 | BRANCH_COST. */ | |
27 | #include "rtl.h" | |
28 | #include "tm_p.h" | |
18d08014 | 29 | #include "tree.h" |
d8a2d370 | 30 | #include "stor-layout.h" |
18d08014 | 31 | #include "basic-block.h" |
cf835838 | 32 | #include "tree-pretty-print.h" |
2fb9a547 AM |
33 | #include "tree-ssa-alias.h" |
34 | #include "internal-fn.h" | |
35 | #include "gimple-fold.h" | |
36 | #include "gimple-expr.h" | |
37 | #include "is-a.h" | |
18f429e2 | 38 | #include "gimple.h" |
5be5c238 | 39 | #include "gimple-iterator.h" |
18f429e2 | 40 | #include "gimplify-me.h" |
442b4905 AM |
41 | #include "gimple-ssa.h" |
42 | #include "tree-cfg.h" | |
43 | #include "tree-phinodes.h" | |
44 | #include "ssa-iterators.h" | |
18d08014 | 45 | #include "tree-pass.h" |
18d08014 | 46 | |
5d2a9da9 AP |
47 | #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT |
48 | #define LOGICAL_OP_NON_SHORT_CIRCUIT \ | |
49 | (BRANCH_COST (optimize_function_for_speed_p (cfun), \ | |
50 | false) >= 2) | |
51 | #endif | |
52 | ||
18d08014 RG |
53 | /* This pass combines COND_EXPRs to simplify control flow. It |
54 | currently recognizes bit tests and comparisons in chains that | |
55 | represent logical and or logical or of two COND_EXPRs. | |
56 | ||
57 | It does so by walking basic blocks in a approximate reverse | |
58 | post-dominator order and trying to match CFG patterns that | |
59 | represent logical and or logical or of two COND_EXPRs. | |
60 | Transformations are done if the COND_EXPR conditions match | |
61 | either | |
62 | ||
63 | 1. two single bit tests X & (1 << Yn) (for logical and) | |
64 | ||
65 | 2. two bit tests X & Yn (for logical or) | |
66 | ||
67 | 3. two comparisons X OPn Y (for logical or) | |
68 | ||
69 | To simplify this pass, removing basic blocks and dead code | |
70 | is left to CFG cleanup and DCE. */ | |
71 | ||
72 | ||
73 | /* Recognize a if-then-else CFG pattern starting to match with the | |
74 | COND_BB basic-block containing the COND_EXPR. The recognized | |
75 | then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
76 | *THEN_BB and/or *ELSE_BB are already set, they are required to | |
77 | match the then and else basic-blocks to make the pattern match. | |
78 | Returns true if the pattern matched, false otherwise. */ | |
79 | ||
80 | static bool | |
81 | recognize_if_then_else (basic_block cond_bb, | |
82 | basic_block *then_bb, basic_block *else_bb) | |
83 | { | |
84 | edge t, e; | |
85 | ||
86 | if (EDGE_COUNT (cond_bb->succs) != 2) | |
87 | return false; | |
88 | ||
89 | /* Find the then/else edges. */ | |
90 | t = EDGE_SUCC (cond_bb, 0); | |
91 | e = EDGE_SUCC (cond_bb, 1); | |
92 | if (!(t->flags & EDGE_TRUE_VALUE)) | |
93 | { | |
94 | edge tmp = t; | |
95 | t = e; | |
96 | e = tmp; | |
97 | } | |
98 | if (!(t->flags & EDGE_TRUE_VALUE) | |
99 | || !(e->flags & EDGE_FALSE_VALUE)) | |
100 | return false; | |
101 | ||
102 | /* Check if the edge destinations point to the required block. */ | |
103 | if (*then_bb | |
104 | && t->dest != *then_bb) | |
105 | return false; | |
106 | if (*else_bb | |
107 | && e->dest != *else_bb) | |
108 | return false; | |
109 | ||
110 | if (!*then_bb) | |
111 | *then_bb = t->dest; | |
112 | if (!*else_bb) | |
113 | *else_bb = e->dest; | |
114 | ||
115 | return true; | |
116 | } | |
117 | ||
118 | /* Verify if the basic block BB does not have side-effects. Return | |
119 | true in this case, else false. */ | |
120 | ||
121 | static bool | |
122 | bb_no_side_effects_p (basic_block bb) | |
123 | { | |
726a989a | 124 | gimple_stmt_iterator gsi; |
18d08014 | 125 | |
726a989a | 126 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
18d08014 | 127 | { |
726a989a | 128 | gimple stmt = gsi_stmt (gsi); |
18d08014 | 129 | |
179184e3 | 130 | if (gimple_has_side_effects (stmt) |
5006671f | 131 | || gimple_vuse (stmt)) |
18d08014 RG |
132 | return false; |
133 | } | |
134 | ||
135 | return true; | |
136 | } | |
137 | ||
138 | /* Verify if all PHI node arguments in DEST for edges from BB1 or | |
139 | BB2 to DEST are the same. This makes the CFG merge point | |
140 | free from side-effects. Return true in this case, else false. */ | |
141 | ||
142 | static bool | |
143 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
144 | { | |
145 | edge e1 = find_edge (bb1, dest); | |
146 | edge e2 = find_edge (bb2, dest); | |
726a989a RB |
147 | gimple_stmt_iterator gsi; |
148 | gimple phi; | |
18d08014 | 149 | |
726a989a RB |
150 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
151 | { | |
152 | phi = gsi_stmt (gsi); | |
153 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), | |
154 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
155 | return false; | |
156 | } | |
18d08014 RG |
157 | |
158 | return true; | |
159 | } | |
160 | ||
d7b339dd RG |
161 | /* Return the best representative SSA name for CANDIDATE which is used |
162 | in a bit test. */ | |
163 | ||
164 | static tree | |
165 | get_name_for_bit_test (tree candidate) | |
166 | { | |
167 | /* Skip single-use names in favor of using the name from a | |
168 | non-widening conversion definition. */ | |
169 | if (TREE_CODE (candidate) == SSA_NAME | |
170 | && has_single_use (candidate)) | |
171 | { | |
726a989a RB |
172 | gimple def_stmt = SSA_NAME_DEF_STMT (candidate); |
173 | if (is_gimple_assign (def_stmt) | |
a6450905 | 174 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
d7b339dd | 175 | { |
726a989a RB |
176 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
177 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
178 | return gimple_assign_rhs1 (def_stmt); | |
d7b339dd RG |
179 | } |
180 | } | |
181 | ||
182 | return candidate; | |
183 | } | |
184 | ||
726a989a | 185 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
18d08014 | 186 | statements. Store the name being tested in *NAME and the bit |
726a989a | 187 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
18d08014 RG |
188 | Returns true if the pattern matched, false otherwise. */ |
189 | ||
190 | static bool | |
777d77b3 | 191 | recognize_single_bit_test (gimple cond, tree *name, tree *bit, bool inv) |
18d08014 | 192 | { |
726a989a | 193 | gimple stmt; |
18d08014 RG |
194 | |
195 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 196 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
197 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
198 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 199 | return false; |
726a989a RB |
200 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
201 | if (!is_gimple_assign (stmt)) | |
18d08014 | 202 | return false; |
18d08014 RG |
203 | |
204 | /* Look at which bit is tested. One form to recognize is | |
205 | D.1985_5 = state_3(D) >> control1_4(D); | |
206 | D.1986_6 = (int) D.1985_5; | |
207 | D.1987_7 = op0 & 1; | |
208 | if (D.1987_7 != 0) */ | |
726a989a RB |
209 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
210 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
211 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
18d08014 | 212 | { |
726a989a | 213 | tree orig_name = gimple_assign_rhs1 (stmt); |
b0569227 RG |
214 | |
215 | /* Look through copies and conversions to eventually | |
216 | find the stmt that computes the shift. */ | |
726a989a RB |
217 | stmt = SSA_NAME_DEF_STMT (orig_name); |
218 | ||
219 | while (is_gimple_assign (stmt) | |
a6450905 RG |
220 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
221 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
222 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))))) | |
223 | || gimple_assign_ssa_name_copy_p (stmt))) | |
224 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
18d08014 | 225 | |
b0569227 | 226 | /* If we found such, decompose it. */ |
726a989a RB |
227 | if (is_gimple_assign (stmt) |
228 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
18d08014 RG |
229 | { |
230 | /* op0 & (1 << op1) */ | |
726a989a RB |
231 | *bit = gimple_assign_rhs2 (stmt); |
232 | *name = gimple_assign_rhs1 (stmt); | |
18d08014 RG |
233 | } |
234 | else | |
235 | { | |
236 | /* t & 1 */ | |
b0569227 | 237 | *bit = integer_zero_node; |
d7b339dd | 238 | *name = get_name_for_bit_test (orig_name); |
18d08014 RG |
239 | } |
240 | ||
241 | return true; | |
242 | } | |
243 | ||
244 | /* Another form is | |
245 | D.1987_7 = op0 & (1 << CST) | |
246 | if (D.1987_7 != 0) */ | |
726a989a RB |
247 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
248 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
249 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
18d08014 | 250 | { |
726a989a | 251 | *name = gimple_assign_rhs1 (stmt); |
18d08014 | 252 | *bit = build_int_cst (integer_type_node, |
726a989a | 253 | tree_log2 (gimple_assign_rhs2 (stmt))); |
18d08014 RG |
254 | return true; |
255 | } | |
256 | ||
257 | /* Another form is | |
258 | D.1986_6 = 1 << control1_4(D) | |
259 | D.1987_7 = op0 & D.1986_6 | |
260 | if (D.1987_7 != 0) */ | |
726a989a RB |
261 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
262 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
263 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
18d08014 | 264 | { |
726a989a | 265 | gimple tmp; |
18d08014 RG |
266 | |
267 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
268 | specifying expression. */ | |
726a989a RB |
269 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
270 | if (is_gimple_assign (tmp) | |
271 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
272 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 273 | { |
726a989a RB |
274 | *name = gimple_assign_rhs2 (stmt); |
275 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
276 | return true; |
277 | } | |
278 | ||
726a989a RB |
279 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
280 | if (is_gimple_assign (tmp) | |
281 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
282 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 283 | { |
726a989a RB |
284 | *name = gimple_assign_rhs1 (stmt); |
285 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
286 | return true; |
287 | } | |
288 | } | |
289 | ||
290 | return false; | |
291 | } | |
292 | ||
726a989a | 293 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
18d08014 RG |
294 | statements. Store the name being tested in *NAME and the bits |
295 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
296 | Returns true if the pattern matched, false otherwise. */ | |
297 | ||
298 | static bool | |
777d77b3 | 299 | recognize_bits_test (gimple cond, tree *name, tree *bits, bool inv) |
18d08014 | 300 | { |
726a989a | 301 | gimple stmt; |
18d08014 RG |
302 | |
303 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 304 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
305 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
306 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 307 | return false; |
726a989a RB |
308 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
309 | if (!is_gimple_assign (stmt) | |
310 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
18d08014 RG |
311 | return false; |
312 | ||
726a989a RB |
313 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
314 | *bits = gimple_assign_rhs2 (stmt); | |
18d08014 RG |
315 | |
316 | return true; | |
317 | } | |
318 | ||
319 | /* If-convert on a and pattern with a common else block. The inner | |
320 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
777d77b3 MG |
321 | inner_inv, outer_inv and result_inv indicate whether the conditions |
322 | are inverted. | |
18d08014 RG |
323 | Returns true if the edges to the common else basic-block were merged. */ |
324 | ||
325 | static bool | |
777d77b3 MG |
326 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
327 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
18d08014 | 328 | { |
726a989a RB |
329 | gimple_stmt_iterator gsi; |
330 | gimple inner_cond, outer_cond; | |
777d77b3 | 331 | tree name1, name2, bit1, bit2, bits1, bits2; |
18d08014 RG |
332 | |
333 | inner_cond = last_stmt (inner_cond_bb); | |
334 | if (!inner_cond | |
726a989a | 335 | || gimple_code (inner_cond) != GIMPLE_COND) |
18d08014 RG |
336 | return false; |
337 | ||
338 | outer_cond = last_stmt (outer_cond_bb); | |
339 | if (!outer_cond | |
726a989a | 340 | || gimple_code (outer_cond) != GIMPLE_COND) |
18d08014 RG |
341 | return false; |
342 | ||
343 | /* See if we test a single bit of the same name in both tests. In | |
344 | that case remove the outer test, merging both else edges, | |
345 | and change the inner one to test for | |
346 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
777d77b3 MG |
347 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
348 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
18d08014 RG |
349 | && name1 == name2) |
350 | { | |
351 | tree t, t2; | |
352 | ||
353 | /* Do it. */ | |
726a989a | 354 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 355 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 356 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
18d08014 | 357 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 358 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
18d08014 | 359 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
726a989a RB |
360 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
361 | true, GSI_SAME_STMT); | |
18d08014 | 362 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
363 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
364 | true, GSI_SAME_STMT); | |
777d77b3 MG |
365 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
366 | boolean_type_node, t2, t); | |
740bb6ad RG |
367 | t = canonicalize_cond_expr_cond (t); |
368 | if (!t) | |
369 | return false; | |
726a989a | 370 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
371 | update_stmt (inner_cond); |
372 | ||
373 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
374 | gimple_cond_set_condition_from_tree (outer_cond, |
375 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
376 | update_stmt (outer_cond); |
377 | ||
378 | if (dump_file) | |
379 | { | |
380 | fprintf (dump_file, "optimizing double bit test to "); | |
381 | print_generic_expr (dump_file, name1, 0); | |
382 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); | |
383 | print_generic_expr (dump_file, bit1, 0); | |
384 | fprintf (dump_file, ") | (1 << "); | |
385 | print_generic_expr (dump_file, bit2, 0); | |
386 | fprintf (dump_file, ")\n"); | |
387 | } | |
388 | ||
389 | return true; | |
390 | } | |
391 | ||
18d08014 RG |
392 | /* See if we have two bit tests of the same name in both tests. |
393 | In that case remove the outer test and change the inner one to | |
394 | test for name & (bits1 | bits2) != 0. */ | |
777d77b3 MG |
395 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
396 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
18d08014 | 397 | { |
726a989a | 398 | gimple_stmt_iterator gsi; |
18d08014 RG |
399 | tree t; |
400 | ||
401 | /* Find the common name which is bit-tested. */ | |
402 | if (name1 == name2) | |
403 | ; | |
404 | else if (bits1 == bits2) | |
405 | { | |
406 | t = name2; | |
407 | name2 = bits2; | |
408 | bits2 = t; | |
409 | t = name1; | |
410 | name1 = bits1; | |
411 | bits1 = t; | |
412 | } | |
413 | else if (name1 == bits2) | |
414 | { | |
415 | t = name2; | |
416 | name2 = bits2; | |
417 | bits2 = t; | |
418 | } | |
419 | else if (bits1 == name2) | |
420 | { | |
421 | t = name1; | |
422 | name1 = bits1; | |
423 | bits1 = t; | |
424 | } | |
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, | |
493 | HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (inner_cond))))); | |
494 | if (inner_cond_code == ERROR_MARK) | |
495 | return false; | |
496 | if (outer_inv) | |
497 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
498 | HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (outer_cond))))); | |
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 | ||
564 | /* Recognize a CFG pattern and dispatch to the appropriate | |
565 | if-conversion helper. We start with BB as the innermost | |
566 | worker basic-block. Returns true if a transformation was done. */ | |
567 | ||
568 | static bool | |
569 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
570 | { | |
571 | basic_block then_bb = NULL, else_bb = NULL; | |
572 | ||
573 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
574 | return false; | |
575 | ||
576 | /* Recognize && and || of two conditions with a common | |
577 | then/else block which entry edges we can merge. That is: | |
578 | if (a || b) | |
579 | ; | |
580 | and | |
581 | if (a && b) | |
582 | ; | |
583 | This requires a single predecessor of the inner cond_bb. */ | |
584 | if (single_pred_p (inner_cond_bb)) | |
585 | { | |
586 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
587 | ||
588 | /* The && form is characterized by a common else_bb with | |
589 | the two edges leading to it mergable. The latter is | |
590 | guaranteed by matching PHI arguments in the else_bb and | |
591 | the inner cond_bb having no side-effects. */ | |
592 | if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
593 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) | |
594 | && bb_no_side_effects_p (inner_cond_bb)) | |
595 | { | |
596 | /* We have | |
597 | <outer_cond_bb> | |
598 | if (q) goto inner_cond_bb; else goto else_bb; | |
599 | <inner_cond_bb> | |
600 | if (p) goto ...; else goto else_bb; | |
601 | ... | |
602 | <else_bb> | |
603 | ... | |
604 | */ | |
777d77b3 MG |
605 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, |
606 | false); | |
607 | } | |
608 | ||
609 | /* And a version where the outer condition is negated. */ | |
610 | if (recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
611 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) | |
612 | && bb_no_side_effects_p (inner_cond_bb)) | |
613 | { | |
614 | /* We have | |
615 | <outer_cond_bb> | |
616 | if (q) goto else_bb; else goto inner_cond_bb; | |
617 | <inner_cond_bb> | |
618 | if (p) goto ...; else goto else_bb; | |
619 | ... | |
620 | <else_bb> | |
621 | ... | |
622 | */ | |
623 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
624 | false); | |
18d08014 RG |
625 | } |
626 | ||
627 | /* The || form is characterized by a common then_bb with the | |
628 | two edges leading to it mergable. The latter is guaranteed | |
629 | by matching PHI arguments in the then_bb and the inner cond_bb | |
630 | having no side-effects. */ | |
631 | if (recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
632 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) | |
633 | && bb_no_side_effects_p (inner_cond_bb)) | |
634 | { | |
635 | /* We have | |
636 | <outer_cond_bb> | |
637 | if (q) goto then_bb; else goto inner_cond_bb; | |
638 | <inner_cond_bb> | |
639 | if (q) goto then_bb; else goto ...; | |
640 | <then_bb> | |
641 | ... | |
642 | */ | |
777d77b3 MG |
643 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, |
644 | true); | |
645 | } | |
646 | ||
647 | /* And a version where the outer condition is negated. */ | |
648 | if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
649 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) | |
650 | && bb_no_side_effects_p (inner_cond_bb)) | |
651 | { | |
652 | /* We have | |
653 | <outer_cond_bb> | |
654 | if (q) goto inner_cond_bb; else goto then_bb; | |
655 | <inner_cond_bb> | |
656 | if (q) goto then_bb; else goto ...; | |
657 | <then_bb> | |
658 | ... | |
659 | */ | |
660 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
661 | true); | |
18d08014 RG |
662 | } |
663 | } | |
664 | ||
665 | return false; | |
666 | } | |
667 | ||
668 | /* Main entry for the tree if-conversion pass. */ | |
669 | ||
670 | static unsigned int | |
671 | tree_ssa_ifcombine (void) | |
672 | { | |
673 | basic_block *bbs; | |
674 | bool cfg_changed = false; | |
675 | int i; | |
676 | ||
3d9c733e | 677 | bbs = single_pred_before_succ_order (); |
6c66f733 | 678 | calculate_dominance_info (CDI_DOMINATORS); |
18d08014 | 679 | |
5d2a9da9 AP |
680 | /* Search every basic block for COND_EXPR we may be able to optimize. |
681 | ||
682 | We walk the blocks in order that guarantees that a block with | |
683 | a single predecessor is processed after the predecessor. | |
684 | This ensures that we collapse outter ifs before visiting the | |
685 | inner ones, and also that we do not try to visit a removed | |
686 | block. This is opposite of PHI-OPT, because we cascade the | |
687 | combining rather than cascading PHIs. */ | |
0cae8d31 | 688 | for (i = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS - 1; i >= 0; i--) |
18d08014 RG |
689 | { |
690 | basic_block bb = bbs[i]; | |
726a989a | 691 | gimple stmt = last_stmt (bb); |
18d08014 RG |
692 | |
693 | if (stmt | |
726a989a | 694 | && gimple_code (stmt) == GIMPLE_COND) |
18d08014 RG |
695 | cfg_changed |= tree_ssa_ifcombine_bb (bb); |
696 | } | |
697 | ||
698 | free (bbs); | |
699 | ||
700 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
701 | } | |
702 | ||
703 | static bool | |
704 | gate_ifcombine (void) | |
705 | { | |
706 | return 1; | |
707 | } | |
708 | ||
27a4cd48 DM |
709 | namespace { |
710 | ||
711 | const pass_data pass_data_tree_ifcombine = | |
8ddbbcae | 712 | { |
27a4cd48 DM |
713 | GIMPLE_PASS, /* type */ |
714 | "ifcombine", /* name */ | |
715 | OPTGROUP_NONE, /* optinfo_flags */ | |
716 | true, /* has_gate */ | |
717 | true, /* has_execute */ | |
718 | TV_TREE_IFCOMBINE, /* tv_id */ | |
719 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
720 | 0, /* properties_provided */ | |
721 | 0, /* properties_destroyed */ | |
722 | 0, /* todo_flags_start */ | |
723 | ( TODO_update_ssa | TODO_verify_ssa ), /* todo_flags_finish */ | |
18d08014 | 724 | }; |
27a4cd48 DM |
725 | |
726 | class pass_tree_ifcombine : public gimple_opt_pass | |
727 | { | |
728 | public: | |
c3284718 RS |
729 | pass_tree_ifcombine (gcc::context *ctxt) |
730 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
27a4cd48 DM |
731 | {} |
732 | ||
733 | /* opt_pass methods: */ | |
734 | bool gate () { return gate_ifcombine (); } | |
735 | unsigned int execute () { return tree_ssa_ifcombine (); } | |
736 | ||
737 | }; // class pass_tree_ifcombine | |
738 | ||
739 | } // anon namespace | |
740 | ||
741 | gimple_opt_pass * | |
742 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
743 | { | |
744 | return new pass_tree_ifcombine (ctxt); | |
745 | } |