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291d763b | 1 | /* Forward propagation of expressions for single use variables. |
3bb6785a | 2 | Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
4ee9c684 | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING. If not, write to | |
67ce556b | 18 | the Free Software Foundation, 51 Franklin Street, Fifth Floor, |
19 | Boston, MA 02110-1301, USA. */ | |
4ee9c684 | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
4ee9c684 | 25 | #include "ggc.h" |
26 | #include "tree.h" | |
27 | #include "rtl.h" | |
28 | #include "tm_p.h" | |
29 | #include "basic-block.h" | |
30 | #include "timevar.h" | |
31 | #include "diagnostic.h" | |
32 | #include "tree-flow.h" | |
33 | #include "tree-pass.h" | |
34 | #include "tree-dump.h" | |
291d763b | 35 | #include "langhooks.h" |
4ee9c684 | 36 | |
291d763b | 37 | /* This pass propagates the RHS of assignment statements into use |
38 | sites of the LHS of the assignment. It's basically a specialized | |
8f628ee8 | 39 | form of tree combination. It is hoped all of this can disappear |
40 | when we have a generalized tree combiner. | |
4ee9c684 | 41 | |
291d763b | 42 | Note carefully that after propagation the resulting statement |
43 | must still be a proper gimple statement. Right now we simply | |
44 | only perform propagations we know will result in valid gimple | |
45 | code. One day we'll want to generalize this code. | |
46 | ||
47 | One class of common cases we handle is forward propagating a single use | |
c78cbec8 | 48 | variable into a COND_EXPR. |
4ee9c684 | 49 | |
50 | bb0: | |
51 | x = a COND b; | |
52 | if (x) goto ... else goto ... | |
53 | ||
54 | Will be transformed into: | |
55 | ||
56 | bb0: | |
57 | if (a COND b) goto ... else goto ... | |
58 | ||
59 | Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1). | |
60 | ||
61 | Or (assuming c1 and c2 are constants): | |
62 | ||
63 | bb0: | |
64 | x = a + c1; | |
65 | if (x EQ/NEQ c2) goto ... else goto ... | |
66 | ||
67 | Will be transformed into: | |
68 | ||
69 | bb0: | |
70 | if (a EQ/NEQ (c2 - c1)) goto ... else goto ... | |
71 | ||
72 | Similarly for x = a - c1. | |
73 | ||
74 | Or | |
75 | ||
76 | bb0: | |
77 | x = !a | |
78 | if (x) goto ... else goto ... | |
79 | ||
80 | Will be transformed into: | |
81 | ||
82 | bb0: | |
83 | if (a == 0) goto ... else goto ... | |
84 | ||
85 | Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1). | |
86 | For these cases, we propagate A into all, possibly more than one, | |
87 | COND_EXPRs that use X. | |
88 | ||
f5c8cff5 | 89 | Or |
90 | ||
91 | bb0: | |
92 | x = (typecast) a | |
93 | if (x) goto ... else goto ... | |
94 | ||
95 | Will be transformed into: | |
96 | ||
97 | bb0: | |
98 | if (a != 0) goto ... else goto ... | |
99 | ||
100 | (Assuming a is an integral type and x is a boolean or x is an | |
101 | integral and a is a boolean.) | |
102 | ||
103 | Similarly for the tests (x == 0), (x != 0), (x == 1) and (x != 1). | |
104 | For these cases, we propagate A into all, possibly more than one, | |
105 | COND_EXPRs that use X. | |
106 | ||
4ee9c684 | 107 | In addition to eliminating the variable and the statement which assigns |
108 | a value to the variable, we may be able to later thread the jump without | |
e6dfde59 | 109 | adding insane complexity in the dominator optimizer. |
4ee9c684 | 110 | |
f5c8cff5 | 111 | Also note these transformations can cascade. We handle this by having |
112 | a worklist of COND_EXPR statements to examine. As we make a change to | |
113 | a statement, we put it back on the worklist to examine on the next | |
114 | iteration of the main loop. | |
115 | ||
291d763b | 116 | A second class of propagation opportunities arises for ADDR_EXPR |
117 | nodes. | |
118 | ||
119 | ptr = &x->y->z; | |
120 | res = *ptr; | |
121 | ||
122 | Will get turned into | |
123 | ||
124 | res = x->y->z; | |
125 | ||
126 | Or | |
127 | ||
128 | ptr = &x[0]; | |
129 | ptr2 = ptr + <constant>; | |
130 | ||
131 | Will get turned into | |
132 | ||
133 | ptr2 = &x[constant/elementsize]; | |
134 | ||
135 | Or | |
136 | ||
137 | ptr = &x[0]; | |
138 | offset = index * element_size; | |
139 | offset_p = (pointer) offset; | |
140 | ptr2 = ptr + offset_p | |
141 | ||
142 | Will get turned into: | |
143 | ||
144 | ptr2 = &x[index]; | |
145 | ||
8f628ee8 | 146 | We also propagate casts into SWITCH_EXPR and COND_EXPR conditions to |
147 | allow us to remove the cast and {NOT_EXPR,NEG_EXPR} into a subsequent | |
148 | {NOT_EXPR,NEG_EXPR}. | |
291d763b | 149 | |
4ee9c684 | 150 | This will (of course) be extended as other needs arise. */ |
151 | ||
148aa112 | 152 | |
153 | /* Set to true if we delete EH edges during the optimization. */ | |
154 | static bool cfg_changed; | |
155 | ||
156 | ||
a3451973 | 157 | /* Given an SSA_NAME VAR, return true if and only if VAR is defined by |
158 | a comparison. */ | |
159 | ||
160 | static bool | |
161 | ssa_name_defined_by_comparison_p (tree var) | |
162 | { | |
163 | tree def = SSA_NAME_DEF_STMT (var); | |
164 | ||
35cc02b5 | 165 | if (TREE_CODE (def) == GIMPLE_MODIFY_STMT) |
a3451973 | 166 | { |
35cc02b5 | 167 | tree rhs = GIMPLE_STMT_OPERAND (def, 1); |
a3451973 | 168 | return COMPARISON_CLASS_P (rhs); |
169 | } | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
e6dfde59 | 174 | /* Forward propagate a single-use variable into COND once. Return a |
175 | new condition if successful. Return NULL_TREE otherwise. */ | |
4ee9c684 | 176 | |
e6dfde59 | 177 | static tree |
178 | forward_propagate_into_cond_1 (tree cond, tree *test_var_p) | |
f5c8cff5 | 179 | { |
e6dfde59 | 180 | tree new_cond = NULL_TREE; |
181 | enum tree_code cond_code = TREE_CODE (cond); | |
182 | tree test_var = NULL_TREE; | |
183 | tree def; | |
184 | tree def_rhs; | |
185 | ||
186 | /* If the condition is not a lone variable or an equality test of an | |
187 | SSA_NAME against an integral constant, then we do not have an | |
188 | optimizable case. | |
189 | ||
190 | Note these conditions also ensure the COND_EXPR has no | |
191 | virtual operands or other side effects. */ | |
192 | if (cond_code != SSA_NAME | |
193 | && !((cond_code == EQ_EXPR || cond_code == NE_EXPR) | |
194 | && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME | |
195 | && CONSTANT_CLASS_P (TREE_OPERAND (cond, 1)) | |
196 | && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1))))) | |
197 | return NULL_TREE; | |
198 | ||
199 | /* Extract the single variable used in the test into TEST_VAR. */ | |
200 | if (cond_code == SSA_NAME) | |
201 | test_var = cond; | |
202 | else | |
203 | test_var = TREE_OPERAND (cond, 0); | |
204 | ||
205 | /* Now get the defining statement for TEST_VAR. Skip this case if | |
35cc02b5 | 206 | it's not defined by some GIMPLE_MODIFY_STMT. */ |
e6dfde59 | 207 | def = SSA_NAME_DEF_STMT (test_var); |
35cc02b5 | 208 | if (TREE_CODE (def) != GIMPLE_MODIFY_STMT) |
e6dfde59 | 209 | return NULL_TREE; |
210 | ||
35cc02b5 | 211 | def_rhs = GIMPLE_STMT_OPERAND (def, 1); |
e6dfde59 | 212 | |
213 | /* If TEST_VAR is set by adding or subtracting a constant | |
214 | from an SSA_NAME, then it is interesting to us as we | |
215 | can adjust the constant in the conditional and thus | |
216 | eliminate the arithmetic operation. */ | |
217 | if (TREE_CODE (def_rhs) == PLUS_EXPR | |
218 | || TREE_CODE (def_rhs) == MINUS_EXPR) | |
4ee9c684 | 219 | { |
e6dfde59 | 220 | tree op0 = TREE_OPERAND (def_rhs, 0); |
221 | tree op1 = TREE_OPERAND (def_rhs, 1); | |
222 | ||
223 | /* The first operand must be an SSA_NAME and the second | |
224 | operand must be a constant. */ | |
225 | if (TREE_CODE (op0) != SSA_NAME | |
226 | || !CONSTANT_CLASS_P (op1) | |
227 | || !INTEGRAL_TYPE_P (TREE_TYPE (op1))) | |
228 | return NULL_TREE; | |
229 | ||
230 | /* Don't propagate if the first operand occurs in | |
231 | an abnormal PHI. */ | |
232 | if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0)) | |
233 | return NULL_TREE; | |
234 | ||
235 | if (has_single_use (test_var)) | |
4ee9c684 | 236 | { |
e6dfde59 | 237 | enum tree_code new_code; |
238 | tree t; | |
239 | ||
240 | /* If the variable was defined via X + C, then we must | |
241 | subtract C from the constant in the conditional. | |
242 | Otherwise we add C to the constant in the | |
243 | conditional. The result must fold into a valid | |
244 | gimple operand to be optimizable. */ | |
245 | new_code = (TREE_CODE (def_rhs) == PLUS_EXPR | |
246 | ? MINUS_EXPR : PLUS_EXPR); | |
247 | t = int_const_binop (new_code, TREE_OPERAND (cond, 1), op1, 0); | |
248 | if (!is_gimple_val (t)) | |
249 | return NULL_TREE; | |
250 | ||
5a12b939 | 251 | new_cond = build2 (cond_code, boolean_type_node, op0, t); |
4ee9c684 | 252 | } |
253 | } | |
4ee9c684 | 254 | |
e6dfde59 | 255 | /* These cases require comparisons of a naked SSA_NAME or |
256 | comparison of an SSA_NAME against zero or one. */ | |
257 | else if (TREE_CODE (cond) == SSA_NAME | |
258 | || integer_zerop (TREE_OPERAND (cond, 1)) | |
259 | || integer_onep (TREE_OPERAND (cond, 1))) | |
4ee9c684 | 260 | { |
e6dfde59 | 261 | /* If TEST_VAR is set from a relational operation |
262 | between two SSA_NAMEs or a combination of an SSA_NAME | |
263 | and a constant, then it is interesting. */ | |
264 | if (COMPARISON_CLASS_P (def_rhs)) | |
4ee9c684 | 265 | { |
e6dfde59 | 266 | tree op0 = TREE_OPERAND (def_rhs, 0); |
267 | tree op1 = TREE_OPERAND (def_rhs, 1); | |
268 | ||
269 | /* Both operands of DEF_RHS must be SSA_NAMEs or | |
270 | constants. */ | |
271 | if ((TREE_CODE (op0) != SSA_NAME | |
272 | && !is_gimple_min_invariant (op0)) | |
273 | || (TREE_CODE (op1) != SSA_NAME | |
274 | && !is_gimple_min_invariant (op1))) | |
275 | return NULL_TREE; | |
276 | ||
277 | /* Don't propagate if the first operand occurs in | |
278 | an abnormal PHI. */ | |
279 | if (TREE_CODE (op0) == SSA_NAME | |
280 | && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0)) | |
281 | return NULL_TREE; | |
282 | ||
283 | /* Don't propagate if the second operand occurs in | |
284 | an abnormal PHI. */ | |
285 | if (TREE_CODE (op1) == SSA_NAME | |
286 | && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op1)) | |
287 | return NULL_TREE; | |
288 | ||
289 | if (has_single_use (test_var)) | |
4ee9c684 | 290 | { |
291 | /* TEST_VAR was set from a relational operator. */ | |
5a12b939 | 292 | new_cond = build2 (TREE_CODE (def_rhs), |
293 | boolean_type_node, op0, op1); | |
4ee9c684 | 294 | |
295 | /* Invert the conditional if necessary. */ | |
296 | if ((cond_code == EQ_EXPR | |
297 | && integer_zerop (TREE_OPERAND (cond, 1))) | |
298 | || (cond_code == NE_EXPR | |
299 | && integer_onep (TREE_OPERAND (cond, 1)))) | |
300 | { | |
301 | new_cond = invert_truthvalue (new_cond); | |
302 | ||
e6dfde59 | 303 | /* If we did not get a simple relational |
304 | expression or bare SSA_NAME, then we can | |
305 | not optimize this case. */ | |
ce45a448 | 306 | if (!COMPARISON_CLASS_P (new_cond) |
4ee9c684 | 307 | && TREE_CODE (new_cond) != SSA_NAME) |
e6dfde59 | 308 | new_cond = NULL_TREE; |
4ee9c684 | 309 | } |
310 | } | |
e6dfde59 | 311 | } |
312 | ||
313 | /* If TEST_VAR is set from a TRUTH_NOT_EXPR, then it | |
314 | is interesting. */ | |
315 | else if (TREE_CODE (def_rhs) == TRUTH_NOT_EXPR) | |
316 | { | |
317 | enum tree_code new_code; | |
318 | ||
319 | def_rhs = TREE_OPERAND (def_rhs, 0); | |
320 | ||
321 | /* DEF_RHS must be an SSA_NAME or constant. */ | |
322 | if (TREE_CODE (def_rhs) != SSA_NAME | |
323 | && !is_gimple_min_invariant (def_rhs)) | |
324 | return NULL_TREE; | |
325 | ||
326 | /* Don't propagate if the operand occurs in | |
327 | an abnormal PHI. */ | |
328 | if (TREE_CODE (def_rhs) == SSA_NAME | |
329 | && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def_rhs)) | |
330 | return NULL_TREE; | |
331 | ||
332 | if (cond_code == SSA_NAME | |
333 | || (cond_code == NE_EXPR | |
334 | && integer_zerop (TREE_OPERAND (cond, 1))) | |
335 | || (cond_code == EQ_EXPR | |
336 | && integer_onep (TREE_OPERAND (cond, 1)))) | |
337 | new_code = EQ_EXPR; | |
338 | else | |
339 | new_code = NE_EXPR; | |
340 | ||
341 | new_cond = build2 (new_code, boolean_type_node, def_rhs, | |
342 | fold_convert (TREE_TYPE (def_rhs), | |
343 | integer_zero_node)); | |
344 | } | |
345 | ||
346 | /* If TEST_VAR was set from a cast of an integer type | |
347 | to a boolean type or a cast of a boolean to an | |
348 | integral, then it is interesting. */ | |
349 | else if (TREE_CODE (def_rhs) == NOP_EXPR | |
350 | || TREE_CODE (def_rhs) == CONVERT_EXPR) | |
351 | { | |
352 | tree outer_type; | |
353 | tree inner_type; | |
354 | ||
355 | outer_type = TREE_TYPE (def_rhs); | |
356 | inner_type = TREE_TYPE (TREE_OPERAND (def_rhs, 0)); | |
357 | ||
358 | if ((TREE_CODE (outer_type) == BOOLEAN_TYPE | |
359 | && INTEGRAL_TYPE_P (inner_type)) | |
360 | || (TREE_CODE (inner_type) == BOOLEAN_TYPE | |
361 | && INTEGRAL_TYPE_P (outer_type))) | |
362 | ; | |
a3451973 | 363 | else if (INTEGRAL_TYPE_P (outer_type) |
364 | && INTEGRAL_TYPE_P (inner_type) | |
365 | && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME | |
366 | && ssa_name_defined_by_comparison_p (TREE_OPERAND (def_rhs, | |
367 | 0))) | |
368 | ; | |
4ee9c684 | 369 | else |
e6dfde59 | 370 | return NULL_TREE; |
371 | ||
372 | /* Don't propagate if the operand occurs in | |
373 | an abnormal PHI. */ | |
374 | if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME | |
375 | && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND | |
376 | (def_rhs, 0))) | |
377 | return NULL_TREE; | |
378 | ||
379 | if (has_single_use (test_var)) | |
4ee9c684 | 380 | { |
f5c8cff5 | 381 | enum tree_code new_code; |
5c9198bd | 382 | tree new_arg; |
f5c8cff5 | 383 | |
4ee9c684 | 384 | if (cond_code == SSA_NAME |
385 | || (cond_code == NE_EXPR | |
386 | && integer_zerop (TREE_OPERAND (cond, 1))) | |
387 | || (cond_code == EQ_EXPR | |
388 | && integer_onep (TREE_OPERAND (cond, 1)))) | |
f5c8cff5 | 389 | new_code = NE_EXPR; |
4ee9c684 | 390 | else |
f5c8cff5 | 391 | new_code = EQ_EXPR; |
392 | ||
5c9198bd | 393 | new_arg = TREE_OPERAND (def_rhs, 0); |
394 | new_cond = build2 (new_code, boolean_type_node, new_arg, | |
395 | fold_convert (TREE_TYPE (new_arg), | |
396 | integer_zero_node)); | |
4ee9c684 | 397 | } |
e6dfde59 | 398 | } |
399 | } | |
4ee9c684 | 400 | |
e6dfde59 | 401 | *test_var_p = test_var; |
402 | return new_cond; | |
403 | } | |
404 | ||
8f628ee8 | 405 | /* COND is a condition of the form: |
406 | ||
407 | x == const or x != const | |
408 | ||
409 | Look back to x's defining statement and see if x is defined as | |
410 | ||
411 | x = (type) y; | |
412 | ||
413 | If const is unchanged if we convert it to type, then we can build | |
414 | the equivalent expression: | |
415 | ||
416 | ||
417 | y == const or y != const | |
418 | ||
419 | Which may allow further optimizations. | |
420 | ||
421 | Return the equivalent comparison or NULL if no such equivalent comparison | |
422 | was found. */ | |
423 | ||
424 | static tree | |
425 | find_equivalent_equality_comparison (tree cond) | |
426 | { | |
427 | tree op0 = TREE_OPERAND (cond, 0); | |
428 | tree op1 = TREE_OPERAND (cond, 1); | |
429 | tree def_stmt = SSA_NAME_DEF_STMT (op0); | |
430 | ||
431 | while (def_stmt | |
35cc02b5 | 432 | && TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT |
433 | && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == SSA_NAME) | |
434 | def_stmt = SSA_NAME_DEF_STMT (GIMPLE_STMT_OPERAND (def_stmt, 1)); | |
8f628ee8 | 435 | |
436 | /* OP0 might have been a parameter, so first make sure it | |
35cc02b5 | 437 | was defined by a GIMPLE_MODIFY_STMT. */ |
438 | if (def_stmt && TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT) | |
8f628ee8 | 439 | { |
35cc02b5 | 440 | tree def_rhs = GIMPLE_STMT_OPERAND (def_stmt, 1); |
8f628ee8 | 441 | |
442 | /* If either operand to the comparison is a pointer to | |
443 | a function, then we can not apply this optimization | |
444 | as some targets require function pointers to be | |
445 | canonicalized and in this case this optimization would | |
446 | eliminate a necessary canonicalization. */ | |
447 | if ((POINTER_TYPE_P (TREE_TYPE (op0)) | |
448 | && TREE_CODE (TREE_TYPE (TREE_TYPE (op0))) == FUNCTION_TYPE) | |
449 | || (POINTER_TYPE_P (TREE_TYPE (op1)) | |
450 | && TREE_CODE (TREE_TYPE (TREE_TYPE (op1))) == FUNCTION_TYPE)) | |
451 | return NULL; | |
452 | ||
35cc02b5 | 453 | /* Now make sure the RHS of the GIMPLE_MODIFY_STMT is a typecast. */ |
8f628ee8 | 454 | if ((TREE_CODE (def_rhs) == NOP_EXPR |
455 | || TREE_CODE (def_rhs) == CONVERT_EXPR) | |
456 | && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME) | |
457 | { | |
458 | tree def_rhs_inner = TREE_OPERAND (def_rhs, 0); | |
459 | tree def_rhs_inner_type = TREE_TYPE (def_rhs_inner); | |
460 | tree new; | |
461 | ||
462 | if (TYPE_PRECISION (def_rhs_inner_type) | |
463 | > TYPE_PRECISION (TREE_TYPE (def_rhs))) | |
464 | return NULL; | |
465 | ||
466 | /* If the inner type of the conversion is a pointer to | |
467 | a function, then we can not apply this optimization | |
468 | as some targets require function pointers to be | |
469 | canonicalized. This optimization would result in | |
470 | canonicalization of the pointer when it was not originally | |
471 | needed/intended. */ | |
472 | if (POINTER_TYPE_P (def_rhs_inner_type) | |
473 | && TREE_CODE (TREE_TYPE (def_rhs_inner_type)) == FUNCTION_TYPE) | |
474 | return NULL; | |
475 | ||
476 | /* What we want to prove is that if we convert OP1 to | |
477 | the type of the object inside the NOP_EXPR that the | |
478 | result is still equivalent to SRC. | |
479 | ||
480 | If that is true, the build and return new equivalent | |
481 | condition which uses the source of the typecast and the | |
482 | new constant (which has only changed its type). */ | |
483 | new = fold_build1 (TREE_CODE (def_rhs), def_rhs_inner_type, op1); | |
484 | STRIP_USELESS_TYPE_CONVERSION (new); | |
485 | if (is_gimple_val (new) && tree_int_cst_equal (new, op1)) | |
486 | return build2 (TREE_CODE (cond), TREE_TYPE (cond), | |
487 | def_rhs_inner, new); | |
488 | } | |
489 | } | |
490 | return NULL; | |
491 | } | |
492 | ||
493 | /* STMT is a COND_EXPR | |
494 | ||
495 | This routine attempts to find equivalent forms of the condition | |
496 | which we may be able to optimize better. */ | |
497 | ||
498 | static void | |
499 | simplify_cond (tree stmt) | |
500 | { | |
501 | tree cond = COND_EXPR_COND (stmt); | |
502 | ||
503 | if (COMPARISON_CLASS_P (cond)) | |
504 | { | |
505 | tree op0 = TREE_OPERAND (cond, 0); | |
506 | tree op1 = TREE_OPERAND (cond, 1); | |
507 | ||
508 | if (TREE_CODE (op0) == SSA_NAME && is_gimple_min_invariant (op1)) | |
509 | { | |
510 | /* First see if we have test of an SSA_NAME against a constant | |
511 | where the SSA_NAME is defined by an earlier typecast which | |
512 | is irrelevant when performing tests against the given | |
513 | constant. */ | |
514 | if (TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR) | |
515 | { | |
516 | tree new_cond = find_equivalent_equality_comparison (cond); | |
517 | ||
518 | if (new_cond) | |
519 | { | |
520 | COND_EXPR_COND (stmt) = new_cond; | |
521 | update_stmt (stmt); | |
522 | } | |
523 | } | |
524 | } | |
525 | } | |
526 | } | |
527 | ||
e6dfde59 | 528 | /* Forward propagate a single-use variable into COND_EXPR as many |
529 | times as possible. */ | |
4ee9c684 | 530 | |
e6dfde59 | 531 | static void |
532 | forward_propagate_into_cond (tree cond_expr) | |
533 | { | |
534 | gcc_assert (TREE_CODE (cond_expr) == COND_EXPR); | |
535 | ||
536 | while (1) | |
537 | { | |
538 | tree test_var = NULL_TREE; | |
539 | tree cond = COND_EXPR_COND (cond_expr); | |
540 | tree new_cond = forward_propagate_into_cond_1 (cond, &test_var); | |
541 | ||
542 | /* Return if unsuccessful. */ | |
543 | if (new_cond == NULL_TREE) | |
544 | break; | |
545 | ||
546 | /* Dump details. */ | |
547 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
548 | { | |
549 | fprintf (dump_file, " Replaced '"); | |
550 | print_generic_expr (dump_file, cond, dump_flags); | |
551 | fprintf (dump_file, "' with '"); | |
552 | print_generic_expr (dump_file, new_cond, dump_flags); | |
553 | fprintf (dump_file, "'\n"); | |
4ee9c684 | 554 | } |
555 | ||
e6dfde59 | 556 | COND_EXPR_COND (cond_expr) = new_cond; |
557 | update_stmt (cond_expr); | |
558 | ||
559 | if (has_zero_uses (test_var)) | |
8275f96f | 560 | { |
e6dfde59 | 561 | tree def = SSA_NAME_DEF_STMT (test_var); |
562 | block_stmt_iterator bsi = bsi_for_stmt (def); | |
f2428b62 | 563 | bsi_remove (&bsi, true); |
8275f96f | 564 | } |
4ee9c684 | 565 | } |
8f628ee8 | 566 | |
567 | /* There are further simplifications that can be performed | |
568 | on COND_EXPRs. Specifically, when comparing an SSA_NAME | |
569 | against a constant where the SSA_NAME is the result of a | |
570 | conversion. Perhaps this should be folded into the rest | |
571 | of the COND_EXPR simplification code. */ | |
572 | simplify_cond (cond_expr); | |
4ee9c684 | 573 | } |
574 | ||
148aa112 | 575 | /* We've just substituted an ADDR_EXPR into stmt. Update all the |
576 | relevant data structures to match. */ | |
577 | ||
578 | static void | |
579 | tidy_after_forward_propagate_addr (tree stmt) | |
580 | { | |
148aa112 | 581 | /* We may have turned a trapping insn into a non-trapping insn. */ |
582 | if (maybe_clean_or_replace_eh_stmt (stmt, stmt) | |
583 | && tree_purge_dead_eh_edges (bb_for_stmt (stmt))) | |
584 | cfg_changed = true; | |
f2fae51f | 585 | |
35cc02b5 | 586 | if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ADDR_EXPR) |
587 | recompute_tree_invariant_for_addr_expr (GIMPLE_STMT_OPERAND (stmt, 1)); | |
f2fae51f | 588 | |
538cbb1e | 589 | mark_new_vars_to_rename (stmt); |
148aa112 | 590 | } |
591 | ||
291d763b | 592 | /* STMT defines LHS which is contains the address of the 0th element |
593 | in an array. USE_STMT uses LHS to compute the address of an | |
594 | arbitrary element within the array. The (variable) byte offset | |
595 | of the element is contained in OFFSET. | |
596 | ||
597 | We walk back through the use-def chains of OFFSET to verify that | |
598 | it is indeed computing the offset of an element within the array | |
599 | and extract the index corresponding to the given byte offset. | |
600 | ||
601 | We then try to fold the entire address expression into a form | |
602 | &array[index]. | |
603 | ||
604 | If we are successful, we replace the right hand side of USE_STMT | |
605 | with the new address computation. */ | |
606 | ||
607 | static bool | |
608 | forward_propagate_addr_into_variable_array_index (tree offset, tree lhs, | |
609 | tree stmt, tree use_stmt) | |
610 | { | |
611 | tree index; | |
612 | ||
35cc02b5 | 613 | /* The offset must be defined by a simple GIMPLE_MODIFY_STMT statement. */ |
614 | if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT) | |
291d763b | 615 | return false; |
616 | ||
617 | /* The RHS of the statement which defines OFFSET must be a gimple | |
618 | cast of another SSA_NAME. */ | |
35cc02b5 | 619 | offset = GIMPLE_STMT_OPERAND (offset, 1); |
291d763b | 620 | if (!is_gimple_cast (offset)) |
621 | return false; | |
622 | ||
623 | offset = TREE_OPERAND (offset, 0); | |
624 | if (TREE_CODE (offset) != SSA_NAME) | |
625 | return false; | |
626 | ||
627 | /* Get the defining statement of the offset before type | |
628 | conversion. */ | |
629 | offset = SSA_NAME_DEF_STMT (offset); | |
630 | ||
631 | /* The statement which defines OFFSET before type conversion | |
35cc02b5 | 632 | must be a simple GIMPLE_MODIFY_STMT. */ |
633 | if (TREE_CODE (offset) != GIMPLE_MODIFY_STMT) | |
291d763b | 634 | return false; |
635 | ||
636 | /* The RHS of the statement which defines OFFSET must be a | |
637 | multiplication of an object by the size of the array elements. | |
638 | This implicitly verifies that the size of the array elements | |
639 | is constant. */ | |
35cc02b5 | 640 | offset = GIMPLE_STMT_OPERAND (offset, 1); |
291d763b | 641 | if (TREE_CODE (offset) != MULT_EXPR |
642 | || TREE_CODE (TREE_OPERAND (offset, 1)) != INTEGER_CST | |
643 | || !simple_cst_equal (TREE_OPERAND (offset, 1), | |
644 | TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (lhs))))) | |
645 | return false; | |
646 | ||
647 | /* The first operand to the MULT_EXPR is the desired index. */ | |
648 | index = TREE_OPERAND (offset, 0); | |
649 | ||
650 | /* Replace the pointer addition with array indexing. */ | |
35cc02b5 | 651 | GIMPLE_STMT_OPERAND (use_stmt, 1) |
652 | = unshare_expr (GIMPLE_STMT_OPERAND (stmt, 1)); | |
653 | TREE_OPERAND (TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0), 1) | |
654 | = index; | |
291d763b | 655 | |
656 | /* That should have created gimple, so there is no need to | |
657 | record information to undo the propagation. */ | |
148aa112 | 658 | fold_stmt_inplace (use_stmt); |
659 | tidy_after_forward_propagate_addr (use_stmt); | |
291d763b | 660 | return true; |
661 | } | |
662 | ||
663 | /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>. | |
664 | ||
3d5cfe81 | 665 | Try to forward propagate the ADDR_EXPR into the use USE_STMT. |
291d763b | 666 | Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF |
3d5cfe81 | 667 | node or for recovery of array indexing from pointer arithmetic. |
6b5a5c42 | 668 | |
669 | CHANGED is an optional pointer to a boolean variable set to true if | |
670 | either the LHS or RHS was changed in the USE_STMT. | |
671 | ||
672 | Return true if the propagation was successful (the propagation can | |
673 | be not totally successful, yet things may have been changed). */ | |
291d763b | 674 | |
675 | static bool | |
6b5a5c42 | 676 | forward_propagate_addr_expr_1 (tree stmt, tree use_stmt, bool *changed) |
291d763b | 677 | { |
35cc02b5 | 678 | tree name = GIMPLE_STMT_OPERAND (stmt, 0); |
3d5cfe81 | 679 | tree lhs, rhs, array_ref; |
291d763b | 680 | |
631d5db6 | 681 | /* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS. |
682 | ADDR_EXPR will not appear on the LHS. */ | |
35cc02b5 | 683 | lhs = GIMPLE_STMT_OPERAND (use_stmt, 0); |
291d763b | 684 | while (TREE_CODE (lhs) == COMPONENT_REF || TREE_CODE (lhs) == ARRAY_REF) |
685 | lhs = TREE_OPERAND (lhs, 0); | |
686 | ||
687 | /* Now see if the LHS node is an INDIRECT_REF using NAME. If so, | |
688 | propagate the ADDR_EXPR into the use of NAME and fold the result. */ | |
689 | if (TREE_CODE (lhs) == INDIRECT_REF && TREE_OPERAND (lhs, 0) == name) | |
690 | { | |
691 | /* This should always succeed in creating gimple, so there is | |
692 | no need to save enough state to undo this propagation. */ | |
35cc02b5 | 693 | TREE_OPERAND (lhs, 0) = unshare_expr (GIMPLE_STMT_OPERAND (stmt, 1)); |
148aa112 | 694 | fold_stmt_inplace (use_stmt); |
695 | tidy_after_forward_propagate_addr (use_stmt); | |
6b5a5c42 | 696 | if (changed) |
697 | *changed = true; | |
291d763b | 698 | } |
699 | ||
700 | /* Trivial case. The use statement could be a trivial copy. We | |
701 | go ahead and handle that case here since it's trivial and | |
702 | removes the need to run copy-prop before this pass to get | |
703 | the best results. Also note that by handling this case here | |
704 | we can catch some cascading effects, ie the single use is | |
705 | in a copy, and the copy is used later by a single INDIRECT_REF | |
706 | for example. */ | |
35cc02b5 | 707 | else if (TREE_CODE (lhs) == SSA_NAME |
708 | && GIMPLE_STMT_OPERAND (use_stmt, 1) == name) | |
291d763b | 709 | { |
35cc02b5 | 710 | GIMPLE_STMT_OPERAND (use_stmt, 1) |
711 | = unshare_expr (GIMPLE_STMT_OPERAND (stmt, 1)); | |
148aa112 | 712 | tidy_after_forward_propagate_addr (use_stmt); |
6b5a5c42 | 713 | if (changed) |
714 | *changed = true; | |
291d763b | 715 | return true; |
716 | } | |
717 | ||
631d5db6 | 718 | /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR |
719 | nodes from the RHS. */ | |
35cc02b5 | 720 | rhs = GIMPLE_STMT_OPERAND (use_stmt, 1); |
631d5db6 | 721 | while (TREE_CODE (rhs) == COMPONENT_REF |
722 | || TREE_CODE (rhs) == ARRAY_REF | |
723 | || TREE_CODE (rhs) == ADDR_EXPR) | |
291d763b | 724 | rhs = TREE_OPERAND (rhs, 0); |
725 | ||
726 | /* Now see if the RHS node is an INDIRECT_REF using NAME. If so, | |
727 | propagate the ADDR_EXPR into the use of NAME and fold the result. */ | |
728 | if (TREE_CODE (rhs) == INDIRECT_REF && TREE_OPERAND (rhs, 0) == name) | |
729 | { | |
730 | /* This should always succeed in creating gimple, so there is | |
731 | no need to save enough state to undo this propagation. */ | |
35cc02b5 | 732 | TREE_OPERAND (rhs, 0) = unshare_expr (GIMPLE_STMT_OPERAND (stmt, 1)); |
148aa112 | 733 | fold_stmt_inplace (use_stmt); |
734 | tidy_after_forward_propagate_addr (use_stmt); | |
6b5a5c42 | 735 | if (changed) |
736 | *changed = true; | |
291d763b | 737 | return true; |
738 | } | |
739 | ||
740 | /* The remaining cases are all for turning pointer arithmetic into | |
741 | array indexing. They only apply when we have the address of | |
742 | element zero in an array. If that is not the case then there | |
743 | is nothing to do. */ | |
35cc02b5 | 744 | array_ref = TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt, 1), 0); |
291d763b | 745 | if (TREE_CODE (array_ref) != ARRAY_REF |
746 | || TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE | |
747 | || !integer_zerop (TREE_OPERAND (array_ref, 1))) | |
748 | return false; | |
749 | ||
750 | /* If the use of the ADDR_EXPR must be a PLUS_EXPR, or else there | |
751 | is nothing to do. */ | |
752 | if (TREE_CODE (rhs) != PLUS_EXPR) | |
753 | return false; | |
754 | ||
755 | /* Try to optimize &x[0] + C where C is a multiple of the size | |
756 | of the elements in X into &x[C/element size]. */ | |
757 | if (TREE_OPERAND (rhs, 0) == name | |
758 | && TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST) | |
759 | { | |
760 | tree orig = unshare_expr (rhs); | |
35cc02b5 | 761 | TREE_OPERAND (rhs, 0) = unshare_expr (GIMPLE_STMT_OPERAND (stmt, 1)); |
291d763b | 762 | |
763 | /* If folding succeeds, then we have just exposed new variables | |
764 | in USE_STMT which will need to be renamed. If folding fails, | |
765 | then we need to put everything back the way it was. */ | |
148aa112 | 766 | if (fold_stmt_inplace (use_stmt)) |
291d763b | 767 | { |
148aa112 | 768 | tidy_after_forward_propagate_addr (use_stmt); |
6b5a5c42 | 769 | if (changed) |
770 | *changed = true; | |
291d763b | 771 | return true; |
772 | } | |
773 | else | |
774 | { | |
35cc02b5 | 775 | GIMPLE_STMT_OPERAND (use_stmt, 1) = orig; |
291d763b | 776 | update_stmt (use_stmt); |
777 | return false; | |
778 | } | |
779 | } | |
780 | ||
781 | /* Try to optimize &x[0] + OFFSET where OFFSET is defined by | |
782 | converting a multiplication of an index by the size of the | |
783 | array elements, then the result is converted into the proper | |
784 | type for the arithmetic. */ | |
785 | if (TREE_OPERAND (rhs, 0) == name | |
786 | && TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME | |
787 | /* Avoid problems with IVopts creating PLUS_EXPRs with a | |
788 | different type than their operands. */ | |
789 | && lang_hooks.types_compatible_p (TREE_TYPE (name), TREE_TYPE (rhs))) | |
790 | { | |
6b5a5c42 | 791 | bool res; |
291d763b | 792 | tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 1)); |
6b5a5c42 | 793 | |
794 | res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs, | |
795 | stmt, use_stmt); | |
796 | if (res && changed) | |
797 | *changed = true; | |
798 | return res; | |
291d763b | 799 | } |
800 | ||
801 | /* Same as the previous case, except the operands of the PLUS_EXPR | |
802 | were reversed. */ | |
803 | if (TREE_OPERAND (rhs, 1) == name | |
804 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME | |
805 | /* Avoid problems with IVopts creating PLUS_EXPRs with a | |
806 | different type than their operands. */ | |
807 | && lang_hooks.types_compatible_p (TREE_TYPE (name), TREE_TYPE (rhs))) | |
808 | { | |
6b5a5c42 | 809 | bool res; |
291d763b | 810 | tree offset_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0)); |
6b5a5c42 | 811 | res = forward_propagate_addr_into_variable_array_index (offset_stmt, lhs, |
812 | stmt, use_stmt); | |
813 | if (res && changed) | |
814 | *changed = true; | |
815 | return res; | |
291d763b | 816 | } |
817 | return false; | |
818 | } | |
819 | ||
3d5cfe81 | 820 | /* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>. |
c96420f8 | 821 | SOME is a pointer to a boolean value indicating whether we |
822 | propagated the address expression anywhere. | |
3d5cfe81 | 823 | |
824 | Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME. | |
825 | Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF | |
826 | node or for recovery of array indexing from pointer arithmetic. | |
827 | Returns true, if all uses have been propagated into. */ | |
828 | ||
829 | static bool | |
c96420f8 | 830 | forward_propagate_addr_expr (tree stmt, bool *some) |
3d5cfe81 | 831 | { |
832 | int stmt_loop_depth = bb_for_stmt (stmt)->loop_depth; | |
35cc02b5 | 833 | tree name = GIMPLE_STMT_OPERAND (stmt, 0); |
3d5cfe81 | 834 | imm_use_iterator iter; |
09aca5bc | 835 | tree use_stmt; |
3d5cfe81 | 836 | bool all = true; |
837 | ||
09aca5bc | 838 | FOR_EACH_IMM_USE_STMT (use_stmt, iter, name) |
3d5cfe81 | 839 | { |
c96420f8 | 840 | bool result; |
3d5cfe81 | 841 | |
842 | /* If the use is not in a simple assignment statement, then | |
843 | there is nothing we can do. */ | |
35cc02b5 | 844 | if (TREE_CODE (use_stmt) != GIMPLE_MODIFY_STMT) |
3d5cfe81 | 845 | { |
846 | all = false; | |
847 | continue; | |
848 | } | |
849 | ||
850 | /* If the use is in a deeper loop nest, then we do not want | |
851 | to propagate the ADDR_EXPR into the loop as that is likely | |
852 | adding expression evaluations into the loop. */ | |
853 | if (bb_for_stmt (use_stmt)->loop_depth > stmt_loop_depth) | |
854 | { | |
855 | all = false; | |
856 | continue; | |
857 | } | |
c96420f8 | 858 | |
6b5a5c42 | 859 | result = forward_propagate_addr_expr_1 (stmt, use_stmt, some); |
860 | *some |= result; | |
c96420f8 | 861 | all &= result; |
3d5cfe81 | 862 | } |
863 | ||
864 | return all; | |
865 | } | |
866 | ||
3a938499 | 867 | /* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y. |
868 | If so, we can change STMT into lhs = y which can later be copy | |
869 | propagated. Similarly for negation. | |
870 | ||
871 | This could trivially be formulated as a forward propagation | |
872 | to immediate uses. However, we already had an implementation | |
873 | from DOM which used backward propagation via the use-def links. | |
874 | ||
875 | It turns out that backward propagation is actually faster as | |
876 | there's less work to do for each NOT/NEG expression we find. | |
877 | Backwards propagation needs to look at the statement in a single | |
878 | backlink. Forward propagation needs to look at potentially more | |
879 | than one forward link. */ | |
880 | ||
881 | static void | |
882 | simplify_not_neg_expr (tree stmt) | |
883 | { | |
35cc02b5 | 884 | tree rhs = GIMPLE_STMT_OPERAND (stmt, 1); |
3a938499 | 885 | tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0)); |
886 | ||
887 | /* See if the RHS_DEF_STMT has the same form as our statement. */ | |
35cc02b5 | 888 | if (TREE_CODE (rhs_def_stmt) == GIMPLE_MODIFY_STMT |
889 | && TREE_CODE (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1)) == TREE_CODE (rhs)) | |
3a938499 | 890 | { |
35cc02b5 | 891 | tree rhs_def_operand = |
892 | TREE_OPERAND (GIMPLE_STMT_OPERAND (rhs_def_stmt, 1), 0); | |
3a938499 | 893 | |
894 | /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */ | |
895 | if (TREE_CODE (rhs_def_operand) == SSA_NAME | |
896 | && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand)) | |
897 | { | |
35cc02b5 | 898 | GIMPLE_STMT_OPERAND (stmt, 1) = rhs_def_operand; |
3a938499 | 899 | update_stmt (stmt); |
900 | } | |
901 | } | |
902 | } | |
3d5cfe81 | 903 | |
b5860aba | 904 | /* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of |
905 | the condition which we may be able to optimize better. */ | |
906 | ||
907 | static void | |
908 | simplify_switch_expr (tree stmt) | |
909 | { | |
910 | tree cond = SWITCH_COND (stmt); | |
911 | tree def, to, ti; | |
912 | ||
913 | /* The optimization that we really care about is removing unnecessary | |
914 | casts. That will let us do much better in propagating the inferred | |
915 | constant at the switch target. */ | |
916 | if (TREE_CODE (cond) == SSA_NAME) | |
917 | { | |
918 | def = SSA_NAME_DEF_STMT (cond); | |
35cc02b5 | 919 | if (TREE_CODE (def) == GIMPLE_MODIFY_STMT) |
b5860aba | 920 | { |
35cc02b5 | 921 | def = GIMPLE_STMT_OPERAND (def, 1); |
b5860aba | 922 | if (TREE_CODE (def) == NOP_EXPR) |
923 | { | |
924 | int need_precision; | |
925 | bool fail; | |
926 | ||
927 | def = TREE_OPERAND (def, 0); | |
928 | ||
929 | #ifdef ENABLE_CHECKING | |
930 | /* ??? Why was Jeff testing this? We are gimple... */ | |
931 | gcc_assert (is_gimple_val (def)); | |
932 | #endif | |
933 | ||
934 | to = TREE_TYPE (cond); | |
935 | ti = TREE_TYPE (def); | |
936 | ||
937 | /* If we have an extension that preserves value, then we | |
938 | can copy the source value into the switch. */ | |
939 | ||
940 | need_precision = TYPE_PRECISION (ti); | |
941 | fail = false; | |
c5237b8b | 942 | if (! INTEGRAL_TYPE_P (ti)) |
943 | fail = true; | |
944 | else if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti)) | |
b5860aba | 945 | fail = true; |
946 | else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti)) | |
947 | need_precision += 1; | |
948 | if (TYPE_PRECISION (to) < need_precision) | |
949 | fail = true; | |
950 | ||
951 | if (!fail) | |
952 | { | |
953 | SWITCH_COND (stmt) = def; | |
954 | update_stmt (stmt); | |
955 | } | |
956 | } | |
957 | } | |
958 | } | |
959 | } | |
960 | ||
4ee9c684 | 961 | /* Main entry point for the forward propagation optimizer. */ |
962 | ||
2a1990e9 | 963 | static unsigned int |
4ee9c684 | 964 | tree_ssa_forward_propagate_single_use_vars (void) |
965 | { | |
f5c8cff5 | 966 | basic_block bb; |
c96420f8 | 967 | unsigned int todoflags = 0; |
4ee9c684 | 968 | |
148aa112 | 969 | cfg_changed = false; |
970 | ||
f5c8cff5 | 971 | FOR_EACH_BB (bb) |
972 | { | |
291d763b | 973 | block_stmt_iterator bsi; |
974 | ||
975 | /* Note we update BSI within the loop as necessary. */ | |
976 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); ) | |
977 | { | |
978 | tree stmt = bsi_stmt (bsi); | |
979 | ||
980 | /* If this statement sets an SSA_NAME to an address, | |
981 | try to propagate the address into the uses of the SSA_NAME. */ | |
35cc02b5 | 982 | if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT) |
291d763b | 983 | { |
35cc02b5 | 984 | tree lhs = GIMPLE_STMT_OPERAND (stmt, 0); |
985 | tree rhs = GIMPLE_STMT_OPERAND (stmt, 1); | |
3a938499 | 986 | |
987 | ||
988 | if (TREE_CODE (lhs) != SSA_NAME) | |
989 | { | |
990 | bsi_next (&bsi); | |
991 | continue; | |
992 | } | |
993 | ||
994 | if (TREE_CODE (rhs) == ADDR_EXPR) | |
995 | { | |
c96420f8 | 996 | bool some = false; |
997 | if (forward_propagate_addr_expr (stmt, &some)) | |
f2428b62 | 998 | bsi_remove (&bsi, true); |
3a938499 | 999 | else |
1000 | bsi_next (&bsi); | |
c96420f8 | 1001 | if (some) |
1002 | todoflags |= TODO_update_smt_usage; | |
3a938499 | 1003 | } |
1004 | else if ((TREE_CODE (rhs) == BIT_NOT_EXPR | |
1005 | || TREE_CODE (rhs) == NEGATE_EXPR) | |
1006 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) | |
1007 | { | |
1008 | simplify_not_neg_expr (stmt); | |
1009 | bsi_next (&bsi); | |
1010 | } | |
291d763b | 1011 | else |
1012 | bsi_next (&bsi); | |
1013 | } | |
b5860aba | 1014 | else if (TREE_CODE (stmt) == SWITCH_EXPR) |
1015 | { | |
1016 | simplify_switch_expr (stmt); | |
1017 | bsi_next (&bsi); | |
1018 | } | |
291d763b | 1019 | else if (TREE_CODE (stmt) == COND_EXPR) |
1020 | { | |
1021 | forward_propagate_into_cond (stmt); | |
1022 | bsi_next (&bsi); | |
1023 | } | |
1024 | else | |
1025 | bsi_next (&bsi); | |
1026 | } | |
f5c8cff5 | 1027 | } |
148aa112 | 1028 | |
1029 | if (cfg_changed) | |
1030 | cleanup_tree_cfg (); | |
c96420f8 | 1031 | return todoflags; |
4ee9c684 | 1032 | } |
1033 | ||
1034 | ||
1035 | static bool | |
1036 | gate_forwprop (void) | |
1037 | { | |
1038 | return 1; | |
1039 | } | |
1040 | ||
1041 | struct tree_opt_pass pass_forwprop = { | |
1042 | "forwprop", /* name */ | |
1043 | gate_forwprop, /* gate */ | |
1044 | tree_ssa_forward_propagate_single_use_vars, /* execute */ | |
1045 | NULL, /* sub */ | |
1046 | NULL, /* next */ | |
1047 | 0, /* static_pass_number */ | |
1048 | TV_TREE_FORWPROP, /* tv_id */ | |
f45a1ca1 | 1049 | PROP_cfg | PROP_ssa |
1050 | | PROP_alias, /* properties_required */ | |
4ee9c684 | 1051 | 0, /* properties_provided */ |
eff665b7 | 1052 | PROP_smt_usage, /* properties_destroyed */ |
4ee9c684 | 1053 | 0, /* todo_flags_start */ |
c96420f8 | 1054 | TODO_dump_func /* todo_flags_finish */ |
abd433a7 | 1055 | | TODO_ggc_collect |
291d763b | 1056 | | TODO_update_ssa | TODO_verify_ssa, |
0f9005dd | 1057 | 0 /* letter */ |
4ee9c684 | 1058 | }; |