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18d08014 | 1 | /* Combining of if-expressions on trees. |
d1e082c2 | 2 | Copyright (C) 2007-2013 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" | |
25 | #include "tree.h" | |
26 | #include "basic-block.h" | |
cf835838 | 27 | #include "tree-pretty-print.h" |
442b4905 AM |
28 | #include "gimple.h" |
29 | #include "gimple-ssa.h" | |
30 | #include "tree-cfg.h" | |
31 | #include "tree-phinodes.h" | |
32 | #include "ssa-iterators.h" | |
18d08014 | 33 | #include "tree-pass.h" |
18d08014 RG |
34 | |
35 | /* This pass combines COND_EXPRs to simplify control flow. It | |
36 | currently recognizes bit tests and comparisons in chains that | |
37 | represent logical and or logical or of two COND_EXPRs. | |
38 | ||
39 | It does so by walking basic blocks in a approximate reverse | |
40 | post-dominator order and trying to match CFG patterns that | |
41 | represent logical and or logical or of two COND_EXPRs. | |
42 | Transformations are done if the COND_EXPR conditions match | |
43 | either | |
44 | ||
45 | 1. two single bit tests X & (1 << Yn) (for logical and) | |
46 | ||
47 | 2. two bit tests X & Yn (for logical or) | |
48 | ||
49 | 3. two comparisons X OPn Y (for logical or) | |
50 | ||
51 | To simplify this pass, removing basic blocks and dead code | |
52 | is left to CFG cleanup and DCE. */ | |
53 | ||
54 | ||
55 | /* Recognize a if-then-else CFG pattern starting to match with the | |
56 | COND_BB basic-block containing the COND_EXPR. The recognized | |
57 | then end else blocks are stored to *THEN_BB and *ELSE_BB. If | |
58 | *THEN_BB and/or *ELSE_BB are already set, they are required to | |
59 | match the then and else basic-blocks to make the pattern match. | |
60 | Returns true if the pattern matched, false otherwise. */ | |
61 | ||
62 | static bool | |
63 | recognize_if_then_else (basic_block cond_bb, | |
64 | basic_block *then_bb, basic_block *else_bb) | |
65 | { | |
66 | edge t, e; | |
67 | ||
68 | if (EDGE_COUNT (cond_bb->succs) != 2) | |
69 | return false; | |
70 | ||
71 | /* Find the then/else edges. */ | |
72 | t = EDGE_SUCC (cond_bb, 0); | |
73 | e = EDGE_SUCC (cond_bb, 1); | |
74 | if (!(t->flags & EDGE_TRUE_VALUE)) | |
75 | { | |
76 | edge tmp = t; | |
77 | t = e; | |
78 | e = tmp; | |
79 | } | |
80 | if (!(t->flags & EDGE_TRUE_VALUE) | |
81 | || !(e->flags & EDGE_FALSE_VALUE)) | |
82 | return false; | |
83 | ||
84 | /* Check if the edge destinations point to the required block. */ | |
85 | if (*then_bb | |
86 | && t->dest != *then_bb) | |
87 | return false; | |
88 | if (*else_bb | |
89 | && e->dest != *else_bb) | |
90 | return false; | |
91 | ||
92 | if (!*then_bb) | |
93 | *then_bb = t->dest; | |
94 | if (!*else_bb) | |
95 | *else_bb = e->dest; | |
96 | ||
97 | return true; | |
98 | } | |
99 | ||
100 | /* Verify if the basic block BB does not have side-effects. Return | |
101 | true in this case, else false. */ | |
102 | ||
103 | static bool | |
104 | bb_no_side_effects_p (basic_block bb) | |
105 | { | |
726a989a | 106 | gimple_stmt_iterator gsi; |
18d08014 | 107 | |
726a989a | 108 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
18d08014 | 109 | { |
726a989a | 110 | gimple stmt = gsi_stmt (gsi); |
18d08014 | 111 | |
179184e3 | 112 | if (gimple_has_side_effects (stmt) |
5006671f | 113 | || gimple_vuse (stmt)) |
18d08014 RG |
114 | return false; |
115 | } | |
116 | ||
117 | return true; | |
118 | } | |
119 | ||
120 | /* Verify if all PHI node arguments in DEST for edges from BB1 or | |
121 | BB2 to DEST are the same. This makes the CFG merge point | |
122 | free from side-effects. Return true in this case, else false. */ | |
123 | ||
124 | static bool | |
125 | same_phi_args_p (basic_block bb1, basic_block bb2, basic_block dest) | |
126 | { | |
127 | edge e1 = find_edge (bb1, dest); | |
128 | edge e2 = find_edge (bb2, dest); | |
726a989a RB |
129 | gimple_stmt_iterator gsi; |
130 | gimple phi; | |
18d08014 | 131 | |
726a989a RB |
132 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
133 | { | |
134 | phi = gsi_stmt (gsi); | |
135 | if (!operand_equal_p (PHI_ARG_DEF_FROM_EDGE (phi, e1), | |
136 | PHI_ARG_DEF_FROM_EDGE (phi, e2), 0)) | |
137 | return false; | |
138 | } | |
18d08014 RG |
139 | |
140 | return true; | |
141 | } | |
142 | ||
d7b339dd RG |
143 | /* Return the best representative SSA name for CANDIDATE which is used |
144 | in a bit test. */ | |
145 | ||
146 | static tree | |
147 | get_name_for_bit_test (tree candidate) | |
148 | { | |
149 | /* Skip single-use names in favor of using the name from a | |
150 | non-widening conversion definition. */ | |
151 | if (TREE_CODE (candidate) == SSA_NAME | |
152 | && has_single_use (candidate)) | |
153 | { | |
726a989a RB |
154 | gimple def_stmt = SSA_NAME_DEF_STMT (candidate); |
155 | if (is_gimple_assign (def_stmt) | |
a6450905 | 156 | && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) |
d7b339dd | 157 | { |
726a989a RB |
158 | if (TYPE_PRECISION (TREE_TYPE (candidate)) |
159 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) | |
160 | return gimple_assign_rhs1 (def_stmt); | |
d7b339dd RG |
161 | } |
162 | } | |
163 | ||
164 | return candidate; | |
165 | } | |
166 | ||
726a989a | 167 | /* Recognize a single bit test pattern in GIMPLE_COND and its defining |
18d08014 | 168 | statements. Store the name being tested in *NAME and the bit |
726a989a | 169 | in *BIT. The GIMPLE_COND computes *NAME & (1 << *BIT). |
18d08014 RG |
170 | Returns true if the pattern matched, false otherwise. */ |
171 | ||
172 | static bool | |
777d77b3 | 173 | recognize_single_bit_test (gimple cond, tree *name, tree *bit, bool inv) |
18d08014 | 174 | { |
726a989a | 175 | gimple stmt; |
18d08014 RG |
176 | |
177 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 178 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
179 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
180 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 181 | return false; |
726a989a RB |
182 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
183 | if (!is_gimple_assign (stmt)) | |
18d08014 | 184 | return false; |
18d08014 RG |
185 | |
186 | /* Look at which bit is tested. One form to recognize is | |
187 | D.1985_5 = state_3(D) >> control1_4(D); | |
188 | D.1986_6 = (int) D.1985_5; | |
189 | D.1987_7 = op0 & 1; | |
190 | if (D.1987_7 != 0) */ | |
726a989a RB |
191 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
192 | && integer_onep (gimple_assign_rhs2 (stmt)) | |
193 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME) | |
18d08014 | 194 | { |
726a989a | 195 | tree orig_name = gimple_assign_rhs1 (stmt); |
b0569227 RG |
196 | |
197 | /* Look through copies and conversions to eventually | |
198 | find the stmt that computes the shift. */ | |
726a989a RB |
199 | stmt = SSA_NAME_DEF_STMT (orig_name); |
200 | ||
201 | while (is_gimple_assign (stmt) | |
a6450905 RG |
202 | && ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
203 | && (TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (stmt))) | |
204 | <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))))) | |
205 | || gimple_assign_ssa_name_copy_p (stmt))) | |
206 | stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); | |
18d08014 | 207 | |
b0569227 | 208 | /* If we found such, decompose it. */ |
726a989a RB |
209 | if (is_gimple_assign (stmt) |
210 | && gimple_assign_rhs_code (stmt) == RSHIFT_EXPR) | |
18d08014 RG |
211 | { |
212 | /* op0 & (1 << op1) */ | |
726a989a RB |
213 | *bit = gimple_assign_rhs2 (stmt); |
214 | *name = gimple_assign_rhs1 (stmt); | |
18d08014 RG |
215 | } |
216 | else | |
217 | { | |
218 | /* t & 1 */ | |
b0569227 | 219 | *bit = integer_zero_node; |
d7b339dd | 220 | *name = get_name_for_bit_test (orig_name); |
18d08014 RG |
221 | } |
222 | ||
223 | return true; | |
224 | } | |
225 | ||
226 | /* Another form is | |
227 | D.1987_7 = op0 & (1 << CST) | |
228 | if (D.1987_7 != 0) */ | |
726a989a RB |
229 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
230 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
231 | && integer_pow2p (gimple_assign_rhs2 (stmt))) | |
18d08014 | 232 | { |
726a989a | 233 | *name = gimple_assign_rhs1 (stmt); |
18d08014 | 234 | *bit = build_int_cst (integer_type_node, |
726a989a | 235 | tree_log2 (gimple_assign_rhs2 (stmt))); |
18d08014 RG |
236 | return true; |
237 | } | |
238 | ||
239 | /* Another form is | |
240 | D.1986_6 = 1 << control1_4(D) | |
241 | D.1987_7 = op0 & D.1986_6 | |
242 | if (D.1987_7 != 0) */ | |
726a989a RB |
243 | if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
244 | && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME | |
245 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME) | |
18d08014 | 246 | { |
726a989a | 247 | gimple tmp; |
18d08014 RG |
248 | |
249 | /* Both arguments of the BIT_AND_EXPR can be the single-bit | |
250 | specifying expression. */ | |
726a989a RB |
251 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
252 | if (is_gimple_assign (tmp) | |
253 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
254 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 255 | { |
726a989a RB |
256 | *name = gimple_assign_rhs2 (stmt); |
257 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
258 | return true; |
259 | } | |
260 | ||
726a989a RB |
261 | tmp = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt)); |
262 | if (is_gimple_assign (tmp) | |
263 | && gimple_assign_rhs_code (tmp) == LSHIFT_EXPR | |
264 | && integer_onep (gimple_assign_rhs1 (tmp))) | |
18d08014 | 265 | { |
726a989a RB |
266 | *name = gimple_assign_rhs1 (stmt); |
267 | *bit = gimple_assign_rhs2 (tmp); | |
18d08014 RG |
268 | return true; |
269 | } | |
270 | } | |
271 | ||
272 | return false; | |
273 | } | |
274 | ||
726a989a | 275 | /* Recognize a bit test pattern in a GIMPLE_COND and its defining |
18d08014 RG |
276 | statements. Store the name being tested in *NAME and the bits |
277 | in *BITS. The COND_EXPR computes *NAME & *BITS. | |
278 | Returns true if the pattern matched, false otherwise. */ | |
279 | ||
280 | static bool | |
777d77b3 | 281 | recognize_bits_test (gimple cond, tree *name, tree *bits, bool inv) |
18d08014 | 282 | { |
726a989a | 283 | gimple stmt; |
18d08014 RG |
284 | |
285 | /* Get at the definition of the result of the bit test. */ | |
777d77b3 | 286 | if (gimple_cond_code (cond) != (inv ? EQ_EXPR : NE_EXPR) |
726a989a RB |
287 | || TREE_CODE (gimple_cond_lhs (cond)) != SSA_NAME |
288 | || !integer_zerop (gimple_cond_rhs (cond))) | |
18d08014 | 289 | return false; |
726a989a RB |
290 | stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)); |
291 | if (!is_gimple_assign (stmt) | |
292 | || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR) | |
18d08014 RG |
293 | return false; |
294 | ||
726a989a RB |
295 | *name = get_name_for_bit_test (gimple_assign_rhs1 (stmt)); |
296 | *bits = gimple_assign_rhs2 (stmt); | |
18d08014 RG |
297 | |
298 | return true; | |
299 | } | |
300 | ||
301 | /* If-convert on a and pattern with a common else block. The inner | |
302 | if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. | |
777d77b3 MG |
303 | inner_inv, outer_inv and result_inv indicate whether the conditions |
304 | are inverted. | |
18d08014 RG |
305 | Returns true if the edges to the common else basic-block were merged. */ |
306 | ||
307 | static bool | |
777d77b3 MG |
308 | ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, |
309 | basic_block outer_cond_bb, bool outer_inv, bool result_inv) | |
18d08014 | 310 | { |
726a989a RB |
311 | gimple_stmt_iterator gsi; |
312 | gimple inner_cond, outer_cond; | |
777d77b3 | 313 | tree name1, name2, bit1, bit2, bits1, bits2; |
18d08014 RG |
314 | |
315 | inner_cond = last_stmt (inner_cond_bb); | |
316 | if (!inner_cond | |
726a989a | 317 | || gimple_code (inner_cond) != GIMPLE_COND) |
18d08014 RG |
318 | return false; |
319 | ||
320 | outer_cond = last_stmt (outer_cond_bb); | |
321 | if (!outer_cond | |
726a989a | 322 | || gimple_code (outer_cond) != GIMPLE_COND) |
18d08014 RG |
323 | return false; |
324 | ||
325 | /* See if we test a single bit of the same name in both tests. In | |
326 | that case remove the outer test, merging both else edges, | |
327 | and change the inner one to test for | |
328 | name & (bit1 | bit2) == (bit1 | bit2). */ | |
777d77b3 MG |
329 | if (recognize_single_bit_test (inner_cond, &name1, &bit1, inner_inv) |
330 | && recognize_single_bit_test (outer_cond, &name2, &bit2, outer_inv) | |
18d08014 RG |
331 | && name1 == name2) |
332 | { | |
333 | tree t, t2; | |
334 | ||
335 | /* Do it. */ | |
726a989a | 336 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 337 | t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 338 | build_int_cst (TREE_TYPE (name1), 1), bit1); |
18d08014 | 339 | t2 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (name1), |
3886f1d0 | 340 | build_int_cst (TREE_TYPE (name1), 1), bit2); |
18d08014 | 341 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), t, t2); |
726a989a RB |
342 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
343 | true, GSI_SAME_STMT); | |
18d08014 | 344 | t2 = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
345 | t2 = force_gimple_operand_gsi (&gsi, t2, true, NULL_TREE, |
346 | true, GSI_SAME_STMT); | |
777d77b3 MG |
347 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, |
348 | boolean_type_node, t2, t); | |
740bb6ad RG |
349 | t = canonicalize_cond_expr_cond (t); |
350 | if (!t) | |
351 | return false; | |
726a989a | 352 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
353 | update_stmt (inner_cond); |
354 | ||
355 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
356 | gimple_cond_set_condition_from_tree (outer_cond, |
357 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
358 | update_stmt (outer_cond); |
359 | ||
360 | if (dump_file) | |
361 | { | |
362 | fprintf (dump_file, "optimizing double bit test to "); | |
363 | print_generic_expr (dump_file, name1, 0); | |
364 | fprintf (dump_file, " & T == T\nwith temporary T = (1 << "); | |
365 | print_generic_expr (dump_file, bit1, 0); | |
366 | fprintf (dump_file, ") | (1 << "); | |
367 | print_generic_expr (dump_file, bit2, 0); | |
368 | fprintf (dump_file, ")\n"); | |
369 | } | |
370 | ||
371 | return true; | |
372 | } | |
373 | ||
18d08014 RG |
374 | /* See if we have two bit tests of the same name in both tests. |
375 | In that case remove the outer test and change the inner one to | |
376 | test for name & (bits1 | bits2) != 0. */ | |
777d77b3 MG |
377 | else if (recognize_bits_test (inner_cond, &name1, &bits1, !inner_inv) |
378 | && recognize_bits_test (outer_cond, &name2, &bits2, !outer_inv)) | |
18d08014 | 379 | { |
726a989a | 380 | gimple_stmt_iterator gsi; |
18d08014 RG |
381 | tree t; |
382 | ||
383 | /* Find the common name which is bit-tested. */ | |
384 | if (name1 == name2) | |
385 | ; | |
386 | else if (bits1 == bits2) | |
387 | { | |
388 | t = name2; | |
389 | name2 = bits2; | |
390 | bits2 = t; | |
391 | t = name1; | |
392 | name1 = bits1; | |
393 | bits1 = t; | |
394 | } | |
395 | else if (name1 == bits2) | |
396 | { | |
397 | t = name2; | |
398 | name2 = bits2; | |
399 | bits2 = t; | |
400 | } | |
401 | else if (bits1 == name2) | |
402 | { | |
403 | t = name1; | |
404 | name1 = bits1; | |
405 | bits1 = t; | |
406 | } | |
407 | else | |
408 | return false; | |
409 | ||
6e548df5 RG |
410 | /* As we strip non-widening conversions in finding a common |
411 | name that is tested make sure to end up with an integral | |
412 | type for building the bit operations. */ | |
413 | if (TYPE_PRECISION (TREE_TYPE (bits1)) | |
414 | >= TYPE_PRECISION (TREE_TYPE (bits2))) | |
415 | { | |
416 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
417 | name1 = fold_convert (TREE_TYPE (bits1), name1); | |
418 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
419 | bits2 = fold_convert (TREE_TYPE (bits1), bits2); | |
420 | } | |
421 | else | |
422 | { | |
423 | bits2 = fold_convert (unsigned_type_for (TREE_TYPE (bits2)), bits2); | |
424 | name1 = fold_convert (TREE_TYPE (bits2), name1); | |
425 | bits1 = fold_convert (unsigned_type_for (TREE_TYPE (bits1)), bits1); | |
426 | bits1 = fold_convert (TREE_TYPE (bits2), bits1); | |
427 | } | |
428 | ||
18d08014 | 429 | /* Do it. */ |
726a989a | 430 | gsi = gsi_for_stmt (inner_cond); |
18d08014 | 431 | t = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (name1), bits1, bits2); |
726a989a RB |
432 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
433 | true, GSI_SAME_STMT); | |
18d08014 | 434 | t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (name1), name1, t); |
726a989a RB |
435 | t = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, |
436 | true, GSI_SAME_STMT); | |
777d77b3 | 437 | t = fold_build2 (result_inv ? NE_EXPR : EQ_EXPR, boolean_type_node, t, |
726a989a | 438 | build_int_cst (TREE_TYPE (t), 0)); |
740bb6ad RG |
439 | t = canonicalize_cond_expr_cond (t); |
440 | if (!t) | |
441 | return false; | |
726a989a | 442 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
443 | update_stmt (inner_cond); |
444 | ||
445 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
446 | gimple_cond_set_condition_from_tree (outer_cond, |
447 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
448 | update_stmt (outer_cond); |
449 | ||
450 | if (dump_file) | |
451 | { | |
452 | fprintf (dump_file, "optimizing bits or bits test to "); | |
453 | print_generic_expr (dump_file, name1, 0); | |
454 | fprintf (dump_file, " & T != 0\nwith temporary T = "); | |
455 | print_generic_expr (dump_file, bits1, 0); | |
456 | fprintf (dump_file, " | "); | |
457 | print_generic_expr (dump_file, bits2, 0); | |
458 | fprintf (dump_file, "\n"); | |
459 | } | |
460 | ||
461 | return true; | |
462 | } | |
463 | ||
777d77b3 MG |
464 | /* See if we have two comparisons that we can merge into one. */ |
465 | else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison | |
e89065a1 | 466 | && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison) |
18d08014 | 467 | { |
18d08014 | 468 | tree t; |
777d77b3 MG |
469 | enum tree_code inner_cond_code = gimple_cond_code (inner_cond); |
470 | enum tree_code outer_cond_code = gimple_cond_code (outer_cond); | |
471 | ||
472 | /* Invert comparisons if necessary (and possible). */ | |
473 | if (inner_inv) | |
474 | inner_cond_code = invert_tree_comparison (inner_cond_code, | |
475 | HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (inner_cond))))); | |
476 | if (inner_cond_code == ERROR_MARK) | |
477 | return false; | |
478 | if (outer_inv) | |
479 | outer_cond_code = invert_tree_comparison (outer_cond_code, | |
480 | HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (outer_cond))))); | |
481 | if (outer_cond_code == ERROR_MARK) | |
482 | return false; | |
483 | /* Don't return false so fast, try maybe_fold_or_comparisons? */ | |
18d08014 | 484 | |
777d77b3 MG |
485 | if (!(t = maybe_fold_and_comparisons (inner_cond_code, |
486 | gimple_cond_lhs (inner_cond), | |
487 | gimple_cond_rhs (inner_cond), | |
488 | outer_cond_code, | |
489 | gimple_cond_lhs (outer_cond), | |
490 | gimple_cond_rhs (outer_cond)))) | |
18d08014 | 491 | return false; |
777d77b3 MG |
492 | if (result_inv) |
493 | t = fold_build1 (TRUTH_NOT_EXPR, TREE_TYPE (t), t); | |
dc575233 RG |
494 | t = canonicalize_cond_expr_cond (t); |
495 | if (!t) | |
496 | return false; | |
726a989a | 497 | gimple_cond_set_condition_from_tree (inner_cond, t); |
18d08014 RG |
498 | update_stmt (inner_cond); |
499 | ||
500 | /* Leave CFG optimization to cfg_cleanup. */ | |
777d77b3 MG |
501 | gimple_cond_set_condition_from_tree (outer_cond, |
502 | outer_inv ? boolean_false_node : boolean_true_node); | |
18d08014 RG |
503 | update_stmt (outer_cond); |
504 | ||
505 | if (dump_file) | |
506 | { | |
507 | fprintf (dump_file, "optimizing two comparisons to "); | |
508 | print_generic_expr (dump_file, t, 0); | |
509 | fprintf (dump_file, "\n"); | |
510 | } | |
511 | ||
512 | return true; | |
513 | } | |
514 | ||
515 | return false; | |
516 | } | |
517 | ||
518 | /* Recognize a CFG pattern and dispatch to the appropriate | |
519 | if-conversion helper. We start with BB as the innermost | |
520 | worker basic-block. Returns true if a transformation was done. */ | |
521 | ||
522 | static bool | |
523 | tree_ssa_ifcombine_bb (basic_block inner_cond_bb) | |
524 | { | |
525 | basic_block then_bb = NULL, else_bb = NULL; | |
526 | ||
527 | if (!recognize_if_then_else (inner_cond_bb, &then_bb, &else_bb)) | |
528 | return false; | |
529 | ||
530 | /* Recognize && and || of two conditions with a common | |
531 | then/else block which entry edges we can merge. That is: | |
532 | if (a || b) | |
533 | ; | |
534 | and | |
535 | if (a && b) | |
536 | ; | |
537 | This requires a single predecessor of the inner cond_bb. */ | |
538 | if (single_pred_p (inner_cond_bb)) | |
539 | { | |
540 | basic_block outer_cond_bb = single_pred (inner_cond_bb); | |
541 | ||
542 | /* The && form is characterized by a common else_bb with | |
543 | the two edges leading to it mergable. The latter is | |
544 | guaranteed by matching PHI arguments in the else_bb and | |
545 | the inner cond_bb having no side-effects. */ | |
546 | if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) | |
547 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) | |
548 | && bb_no_side_effects_p (inner_cond_bb)) | |
549 | { | |
550 | /* We have | |
551 | <outer_cond_bb> | |
552 | if (q) goto inner_cond_bb; else goto else_bb; | |
553 | <inner_cond_bb> | |
554 | if (p) goto ...; else goto else_bb; | |
555 | ... | |
556 | <else_bb> | |
557 | ... | |
558 | */ | |
777d77b3 MG |
559 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, |
560 | false); | |
561 | } | |
562 | ||
563 | /* And a version where the outer condition is negated. */ | |
564 | if (recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) | |
565 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) | |
566 | && bb_no_side_effects_p (inner_cond_bb)) | |
567 | { | |
568 | /* We have | |
569 | <outer_cond_bb> | |
570 | if (q) goto else_bb; else goto inner_cond_bb; | |
571 | <inner_cond_bb> | |
572 | if (p) goto ...; else goto else_bb; | |
573 | ... | |
574 | <else_bb> | |
575 | ... | |
576 | */ | |
577 | return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, | |
578 | false); | |
18d08014 RG |
579 | } |
580 | ||
581 | /* The || form is characterized by a common then_bb with the | |
582 | two edges leading to it mergable. The latter is guaranteed | |
583 | by matching PHI arguments in the then_bb and the inner cond_bb | |
584 | having no side-effects. */ | |
585 | if (recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) | |
586 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) | |
587 | && bb_no_side_effects_p (inner_cond_bb)) | |
588 | { | |
589 | /* We have | |
590 | <outer_cond_bb> | |
591 | if (q) goto then_bb; else goto inner_cond_bb; | |
592 | <inner_cond_bb> | |
593 | if (q) goto then_bb; else goto ...; | |
594 | <then_bb> | |
595 | ... | |
596 | */ | |
777d77b3 MG |
597 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, |
598 | true); | |
599 | } | |
600 | ||
601 | /* And a version where the outer condition is negated. */ | |
602 | if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) | |
603 | && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) | |
604 | && bb_no_side_effects_p (inner_cond_bb)) | |
605 | { | |
606 | /* We have | |
607 | <outer_cond_bb> | |
608 | if (q) goto inner_cond_bb; else goto then_bb; | |
609 | <inner_cond_bb> | |
610 | if (q) goto then_bb; else goto ...; | |
611 | <then_bb> | |
612 | ... | |
613 | */ | |
614 | return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, | |
615 | true); | |
18d08014 RG |
616 | } |
617 | } | |
618 | ||
619 | return false; | |
620 | } | |
621 | ||
622 | /* Main entry for the tree if-conversion pass. */ | |
623 | ||
624 | static unsigned int | |
625 | tree_ssa_ifcombine (void) | |
626 | { | |
627 | basic_block *bbs; | |
628 | bool cfg_changed = false; | |
629 | int i; | |
630 | ||
3d9c733e | 631 | bbs = single_pred_before_succ_order (); |
6c66f733 | 632 | calculate_dominance_info (CDI_DOMINATORS); |
18d08014 RG |
633 | |
634 | for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; ++i) | |
635 | { | |
636 | basic_block bb = bbs[i]; | |
726a989a | 637 | gimple stmt = last_stmt (bb); |
18d08014 RG |
638 | |
639 | if (stmt | |
726a989a | 640 | && gimple_code (stmt) == GIMPLE_COND) |
18d08014 RG |
641 | cfg_changed |= tree_ssa_ifcombine_bb (bb); |
642 | } | |
643 | ||
644 | free (bbs); | |
645 | ||
646 | return cfg_changed ? TODO_cleanup_cfg : 0; | |
647 | } | |
648 | ||
649 | static bool | |
650 | gate_ifcombine (void) | |
651 | { | |
652 | return 1; | |
653 | } | |
654 | ||
27a4cd48 DM |
655 | namespace { |
656 | ||
657 | const pass_data pass_data_tree_ifcombine = | |
8ddbbcae | 658 | { |
27a4cd48 DM |
659 | GIMPLE_PASS, /* type */ |
660 | "ifcombine", /* name */ | |
661 | OPTGROUP_NONE, /* optinfo_flags */ | |
662 | true, /* has_gate */ | |
663 | true, /* has_execute */ | |
664 | TV_TREE_IFCOMBINE, /* tv_id */ | |
665 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
666 | 0, /* properties_provided */ | |
667 | 0, /* properties_destroyed */ | |
668 | 0, /* todo_flags_start */ | |
669 | ( TODO_update_ssa | TODO_verify_ssa ), /* todo_flags_finish */ | |
18d08014 | 670 | }; |
27a4cd48 DM |
671 | |
672 | class pass_tree_ifcombine : public gimple_opt_pass | |
673 | { | |
674 | public: | |
c3284718 RS |
675 | pass_tree_ifcombine (gcc::context *ctxt) |
676 | : gimple_opt_pass (pass_data_tree_ifcombine, ctxt) | |
27a4cd48 DM |
677 | {} |
678 | ||
679 | /* opt_pass methods: */ | |
680 | bool gate () { return gate_ifcombine (); } | |
681 | unsigned int execute () { return tree_ssa_ifcombine (); } | |
682 | ||
683 | }; // class pass_tree_ifcombine | |
684 | ||
685 | } // anon namespace | |
686 | ||
687 | gimple_opt_pass * | |
688 | make_pass_tree_ifcombine (gcc::context *ctxt) | |
689 | { | |
690 | return new pass_tree_ifcombine (ctxt); | |
691 | } |