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6de9cd9a | 1 | /* Conditional constant propagation pass for the GNU compiler. |
1cdaa211 RG |
2 | Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, |
3 | 2010 Free Software Foundation, Inc. | |
6de9cd9a DN |
4 | Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> |
5 | Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
6 | ||
7 | This file is part of GCC. | |
b8698a0f | 8 | |
6de9cd9a DN |
9 | GCC is free software; you can redistribute it and/or modify it |
10 | under the terms of the GNU General Public License as published by the | |
9dcd6f09 | 11 | Free Software Foundation; either version 3, or (at your option) any |
6de9cd9a | 12 | later version. |
b8698a0f | 13 | |
6de9cd9a DN |
14 | GCC is distributed in the hope that it will be useful, but WITHOUT |
15 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
b8698a0f | 18 | |
6de9cd9a | 19 | You should have received a copy of the GNU General Public License |
9dcd6f09 NC |
20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a | 22 | |
0bca51f0 DN |
23 | /* Conditional constant propagation (CCP) is based on the SSA |
24 | propagation engine (tree-ssa-propagate.c). Constant assignments of | |
25 | the form VAR = CST are propagated from the assignments into uses of | |
26 | VAR, which in turn may generate new constants. The simulation uses | |
27 | a four level lattice to keep track of constant values associated | |
28 | with SSA names. Given an SSA name V_i, it may take one of the | |
29 | following values: | |
30 | ||
106dec71 ZD |
31 | UNINITIALIZED -> the initial state of the value. This value |
32 | is replaced with a correct initial value | |
33 | the first time the value is used, so the | |
34 | rest of the pass does not need to care about | |
35 | it. Using this value simplifies initialization | |
36 | of the pass, and prevents us from needlessly | |
37 | scanning statements that are never reached. | |
0bca51f0 DN |
38 | |
39 | UNDEFINED -> V_i is a local variable whose definition | |
40 | has not been processed yet. Therefore we | |
41 | don't yet know if its value is a constant | |
42 | or not. | |
43 | ||
44 | CONSTANT -> V_i has been found to hold a constant | |
45 | value C. | |
46 | ||
47 | VARYING -> V_i cannot take a constant value, or if it | |
48 | does, it is not possible to determine it | |
49 | at compile time. | |
50 | ||
51 | The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
52 | ||
53 | 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
54 | evaluates into a constant and conditional jumps whose predicate | |
55 | evaluates into a boolean true or false. When an assignment of | |
56 | the form V_i = CONST is found, V_i's lattice value is set to | |
57 | CONSTANT and CONST is associated with it. This causes the | |
58 | propagation engine to add all the SSA edges coming out the | |
59 | assignment into the worklists, so that statements that use V_i | |
60 | can be visited. | |
61 | ||
62 | If the statement is a conditional with a constant predicate, we | |
63 | mark the outgoing edges as executable or not executable | |
64 | depending on the predicate's value. This is then used when | |
65 | visiting PHI nodes to know when a PHI argument can be ignored. | |
b8698a0f | 66 | |
0bca51f0 DN |
67 | |
68 | 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
69 | same constant C, then the LHS of the PHI is set to C. This | |
70 | evaluation is known as the "meet operation". Since one of the | |
71 | goals of this evaluation is to optimistically return constant | |
72 | values as often as possible, it uses two main short cuts: | |
73 | ||
74 | - If an argument is flowing in through a non-executable edge, it | |
75 | is ignored. This is useful in cases like this: | |
76 | ||
77 | if (PRED) | |
78 | a_9 = 3; | |
79 | else | |
80 | a_10 = 100; | |
81 | a_11 = PHI (a_9, a_10) | |
82 | ||
83 | If PRED is known to always evaluate to false, then we can | |
84 | assume that a_11 will always take its value from a_10, meaning | |
85 | that instead of consider it VARYING (a_9 and a_10 have | |
86 | different values), we can consider it CONSTANT 100. | |
87 | ||
88 | - If an argument has an UNDEFINED value, then it does not affect | |
89 | the outcome of the meet operation. If a variable V_i has an | |
90 | UNDEFINED value, it means that either its defining statement | |
91 | hasn't been visited yet or V_i has no defining statement, in | |
92 | which case the original symbol 'V' is being used | |
93 | uninitialized. Since 'V' is a local variable, the compiler | |
94 | may assume any initial value for it. | |
95 | ||
96 | ||
97 | After propagation, every variable V_i that ends up with a lattice | |
98 | value of CONSTANT will have the associated constant value in the | |
99 | array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
100 | final substitution and folding. | |
101 | ||
102 | ||
103 | Constant propagation in stores and loads (STORE-CCP) | |
104 | ---------------------------------------------------- | |
105 | ||
106 | While CCP has all the logic to propagate constants in GIMPLE | |
107 | registers, it is missing the ability to associate constants with | |
108 | stores and loads (i.e., pointer dereferences, structures and | |
109 | global/aliased variables). We don't keep loads and stores in | |
110 | SSA, but we do build a factored use-def web for them (in the | |
111 | virtual operands). | |
112 | ||
113 | For instance, consider the following code fragment: | |
114 | ||
115 | struct A a; | |
116 | const int B = 42; | |
117 | ||
118 | void foo (int i) | |
119 | { | |
120 | if (i > 10) | |
121 | a.a = 42; | |
122 | else | |
123 | { | |
124 | a.b = 21; | |
125 | a.a = a.b + 21; | |
126 | } | |
127 | ||
128 | if (a.a != B) | |
129 | never_executed (); | |
130 | } | |
131 | ||
132 | We should be able to deduce that the predicate 'a.a != B' is always | |
133 | false. To achieve this, we associate constant values to the SSA | |
38635499 DN |
134 | names in the VDEF operands for each store. Additionally, |
135 | since we also glob partial loads/stores with the base symbol, we | |
136 | also keep track of the memory reference where the constant value | |
137 | was stored (in the MEM_REF field of PROP_VALUE_T). For instance, | |
0bca51f0 | 138 | |
38635499 | 139 | # a_5 = VDEF <a_4> |
0bca51f0 DN |
140 | a.a = 2; |
141 | ||
142 | # VUSE <a_5> | |
143 | x_3 = a.b; | |
144 | ||
145 | In the example above, CCP will associate value '2' with 'a_5', but | |
146 | it would be wrong to replace the load from 'a.b' with '2', because | |
147 | '2' had been stored into a.a. | |
148 | ||
106dec71 ZD |
149 | Note that the initial value of virtual operands is VARYING, not |
150 | UNDEFINED. Consider, for instance global variables: | |
0bca51f0 DN |
151 | |
152 | int A; | |
153 | ||
154 | foo (int i) | |
155 | { | |
156 | if (i_3 > 10) | |
157 | A_4 = 3; | |
158 | # A_5 = PHI (A_4, A_2); | |
159 | ||
160 | # VUSE <A_5> | |
161 | A.0_6 = A; | |
162 | ||
163 | return A.0_6; | |
164 | } | |
165 | ||
166 | The value of A_2 cannot be assumed to be UNDEFINED, as it may have | |
167 | been defined outside of foo. If we were to assume it UNDEFINED, we | |
106dec71 | 168 | would erroneously optimize the above into 'return 3;'. |
0bca51f0 DN |
169 | |
170 | Though STORE-CCP is not too expensive, it does have to do more work | |
171 | than regular CCP, so it is only enabled at -O2. Both regular CCP | |
172 | and STORE-CCP use the exact same algorithm. The only distinction | |
173 | is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is | |
174 | set to true. This affects the evaluation of statements and PHI | |
175 | nodes. | |
6de9cd9a DN |
176 | |
177 | References: | |
178 | ||
179 | Constant propagation with conditional branches, | |
180 | Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
181 | ||
182 | Building an Optimizing Compiler, | |
183 | Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
184 | ||
185 | Advanced Compiler Design and Implementation, | |
186 | Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
187 | ||
188 | #include "config.h" | |
189 | #include "system.h" | |
190 | #include "coretypes.h" | |
191 | #include "tm.h" | |
6de9cd9a | 192 | #include "tree.h" |
750628d8 | 193 | #include "flags.h" |
6de9cd9a | 194 | #include "tm_p.h" |
6de9cd9a | 195 | #include "basic-block.h" |
750628d8 | 196 | #include "output.h" |
750628d8 | 197 | #include "function.h" |
cf835838 JM |
198 | #include "tree-pretty-print.h" |
199 | #include "gimple-pretty-print.h" | |
750628d8 | 200 | #include "timevar.h" |
6de9cd9a | 201 | #include "tree-dump.h" |
750628d8 | 202 | #include "tree-flow.h" |
6de9cd9a | 203 | #include "tree-pass.h" |
750628d8 | 204 | #include "tree-ssa-propagate.h" |
53a8f709 | 205 | #include "value-prof.h" |
750628d8 | 206 | #include "langhooks.h" |
ae3df618 | 207 | #include "target.h" |
6ac01510 | 208 | #include "toplev.h" |
74fe548b | 209 | #include "dbgcnt.h" |
6de9cd9a DN |
210 | |
211 | ||
212 | /* Possible lattice values. */ | |
213 | typedef enum | |
214 | { | |
106dec71 | 215 | UNINITIALIZED, |
6de9cd9a DN |
216 | UNDEFINED, |
217 | CONSTANT, | |
218 | VARYING | |
0bca51f0 | 219 | } ccp_lattice_t; |
6de9cd9a | 220 | |
0bca51f0 DN |
221 | /* Array of propagated constant values. After propagation, |
222 | CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
223 | the constant is held in an SSA name representing a memory store | |
38635499 DN |
224 | (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual |
225 | memory reference used to store (i.e., the LHS of the assignment | |
226 | doing the store). */ | |
404f4351 | 227 | static prop_value_t *const_val; |
6de9cd9a | 228 | |
25e20805 | 229 | static void canonicalize_float_value (prop_value_t *); |
f61e18ec | 230 | static bool ccp_fold_stmt (gimple_stmt_iterator *); |
25e20805 | 231 | |
0bca51f0 | 232 | /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ |
95eec0d6 DB |
233 | |
234 | static void | |
0bca51f0 | 235 | dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) |
95eec0d6 | 236 | { |
750628d8 | 237 | switch (val.lattice_val) |
95eec0d6 | 238 | { |
0bca51f0 DN |
239 | case UNINITIALIZED: |
240 | fprintf (outf, "%sUNINITIALIZED", prefix); | |
241 | break; | |
750628d8 DN |
242 | case UNDEFINED: |
243 | fprintf (outf, "%sUNDEFINED", prefix); | |
244 | break; | |
245 | case VARYING: | |
246 | fprintf (outf, "%sVARYING", prefix); | |
247 | break; | |
750628d8 DN |
248 | case CONSTANT: |
249 | fprintf (outf, "%sCONSTANT ", prefix); | |
0bca51f0 | 250 | print_generic_expr (outf, val.value, dump_flags); |
750628d8 DN |
251 | break; |
252 | default: | |
1e128c5f | 253 | gcc_unreachable (); |
750628d8 | 254 | } |
95eec0d6 | 255 | } |
6de9cd9a | 256 | |
6de9cd9a | 257 | |
0bca51f0 DN |
258 | /* Print lattice value VAL to stderr. */ |
259 | ||
260 | void debug_lattice_value (prop_value_t val); | |
261 | ||
24e47c76 | 262 | DEBUG_FUNCTION void |
0bca51f0 DN |
263 | debug_lattice_value (prop_value_t val) |
264 | { | |
265 | dump_lattice_value (stderr, "", val); | |
266 | fprintf (stderr, "\n"); | |
267 | } | |
6de9cd9a | 268 | |
6de9cd9a | 269 | |
0bca51f0 DN |
270 | /* Compute a default value for variable VAR and store it in the |
271 | CONST_VAL array. The following rules are used to get default | |
272 | values: | |
95eec0d6 | 273 | |
0bca51f0 DN |
274 | 1- Global and static variables that are declared constant are |
275 | considered CONSTANT. | |
276 | ||
277 | 2- Any other value is considered UNDEFINED. This is useful when | |
750628d8 DN |
278 | considering PHI nodes. PHI arguments that are undefined do not |
279 | change the constant value of the PHI node, which allows for more | |
0bca51f0 | 280 | constants to be propagated. |
6de9cd9a | 281 | |
caf55296 | 282 | 3- Variables defined by statements other than assignments and PHI |
0bca51f0 | 283 | nodes are considered VARYING. |
6de9cd9a | 284 | |
caf55296 | 285 | 4- Initial values of variables that are not GIMPLE registers are |
106dec71 | 286 | considered VARYING. */ |
6de9cd9a | 287 | |
0bca51f0 DN |
288 | static prop_value_t |
289 | get_default_value (tree var) | |
290 | { | |
291 | tree sym = SSA_NAME_VAR (var); | |
dce2b2f6 | 292 | prop_value_t val = { UNINITIALIZED, NULL_TREE }; |
e8114fba RG |
293 | gimple stmt; |
294 | ||
295 | stmt = SSA_NAME_DEF_STMT (var); | |
296 | ||
297 | if (gimple_nop_p (stmt)) | |
6de9cd9a | 298 | { |
e8114fba RG |
299 | /* Variables defined by an empty statement are those used |
300 | before being initialized. If VAR is a local variable, we | |
301 | can assume initially that it is UNDEFINED, otherwise we must | |
302 | consider it VARYING. */ | |
303 | if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) | |
304 | val.lattice_val = UNDEFINED; | |
305 | else | |
306 | val.lattice_val = VARYING; | |
6de9cd9a | 307 | } |
e8114fba RG |
308 | else if (is_gimple_assign (stmt) |
309 | /* Value-returning GIMPLE_CALL statements assign to | |
310 | a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
311 | || (is_gimple_call (stmt) | |
312 | && gimple_call_lhs (stmt) != NULL_TREE) | |
313 | || gimple_code (stmt) == GIMPLE_PHI) | |
750628d8 | 314 | { |
e8114fba RG |
315 | tree cst; |
316 | if (gimple_assign_single_p (stmt) | |
317 | && DECL_P (gimple_assign_rhs1 (stmt)) | |
318 | && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) | |
0bca51f0 | 319 | { |
e8114fba RG |
320 | val.lattice_val = CONSTANT; |
321 | val.value = cst; | |
0bca51f0 DN |
322 | } |
323 | else | |
e8114fba RG |
324 | /* Any other variable defined by an assignment or a PHI node |
325 | is considered UNDEFINED. */ | |
326 | val.lattice_val = UNDEFINED; | |
327 | } | |
328 | else | |
329 | { | |
330 | /* Otherwise, VAR will never take on a constant value. */ | |
331 | val.lattice_val = VARYING; | |
750628d8 | 332 | } |
6de9cd9a | 333 | |
750628d8 DN |
334 | return val; |
335 | } | |
6de9cd9a | 336 | |
6de9cd9a | 337 | |
106dec71 | 338 | /* Get the constant value associated with variable VAR. */ |
6de9cd9a | 339 | |
106dec71 ZD |
340 | static inline prop_value_t * |
341 | get_value (tree var) | |
0bca51f0 | 342 | { |
ed97ddc6 | 343 | prop_value_t *val; |
106dec71 | 344 | |
ed97ddc6 RG |
345 | if (const_val == NULL) |
346 | return NULL; | |
347 | ||
348 | val = &const_val[SSA_NAME_VERSION (var)]; | |
106dec71 | 349 | if (val->lattice_val == UNINITIALIZED) |
6de9cd9a DN |
350 | *val = get_default_value (var); |
351 | ||
25e20805 RG |
352 | canonicalize_float_value (val); |
353 | ||
6de9cd9a DN |
354 | return val; |
355 | } | |
356 | ||
106dec71 ZD |
357 | /* Sets the value associated with VAR to VARYING. */ |
358 | ||
359 | static inline void | |
360 | set_value_varying (tree var) | |
361 | { | |
362 | prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
363 | ||
364 | val->lattice_val = VARYING; | |
365 | val->value = NULL_TREE; | |
106dec71 | 366 | } |
6de9cd9a | 367 | |
fbb5445b L |
368 | /* For float types, modify the value of VAL to make ccp work correctly |
369 | for non-standard values (-0, NaN): | |
370 | ||
371 | If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
372 | If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
373 | This is to fix the following problem (see PR 29921): Suppose we have | |
374 | ||
375 | x = 0.0 * y | |
376 | ||
377 | and we set value of y to NaN. This causes value of x to be set to NaN. | |
378 | When we later determine that y is in fact VARYING, fold uses the fact | |
379 | that HONOR_NANS is false, and we try to change the value of x to 0, | |
380 | causing an ICE. With HONOR_NANS being false, the real appearance of | |
381 | NaN would cause undefined behavior, though, so claiming that y (and x) | |
382 | are UNDEFINED initially is correct. */ | |
383 | ||
384 | static void | |
385 | canonicalize_float_value (prop_value_t *val) | |
386 | { | |
387 | enum machine_mode mode; | |
388 | tree type; | |
389 | REAL_VALUE_TYPE d; | |
390 | ||
391 | if (val->lattice_val != CONSTANT | |
392 | || TREE_CODE (val->value) != REAL_CST) | |
393 | return; | |
394 | ||
395 | d = TREE_REAL_CST (val->value); | |
396 | type = TREE_TYPE (val->value); | |
397 | mode = TYPE_MODE (type); | |
398 | ||
399 | if (!HONOR_SIGNED_ZEROS (mode) | |
400 | && REAL_VALUE_MINUS_ZERO (d)) | |
401 | { | |
402 | val->value = build_real (type, dconst0); | |
403 | return; | |
404 | } | |
405 | ||
406 | if (!HONOR_NANS (mode) | |
407 | && REAL_VALUE_ISNAN (d)) | |
408 | { | |
409 | val->lattice_val = UNDEFINED; | |
410 | val->value = NULL; | |
fbb5445b L |
411 | return; |
412 | } | |
413 | } | |
414 | ||
0bca51f0 DN |
415 | /* Set the value for variable VAR to NEW_VAL. Return true if the new |
416 | value is different from VAR's previous value. */ | |
6de9cd9a | 417 | |
750628d8 | 418 | static bool |
0bca51f0 | 419 | set_lattice_value (tree var, prop_value_t new_val) |
6de9cd9a | 420 | { |
106dec71 | 421 | prop_value_t *old_val = get_value (var); |
0bca51f0 | 422 | |
fbb5445b L |
423 | canonicalize_float_value (&new_val); |
424 | ||
0bca51f0 | 425 | /* Lattice transitions must always be monotonically increasing in |
106dec71 ZD |
426 | value. If *OLD_VAL and NEW_VAL are the same, return false to |
427 | inform the caller that this was a non-transition. */ | |
428 | ||
fc9962ee | 429 | gcc_assert (old_val->lattice_val < new_val.lattice_val |
0bca51f0 | 430 | || (old_val->lattice_val == new_val.lattice_val |
fc9962ee | 431 | && ((!old_val->value && !new_val.value) |
dce2b2f6 | 432 | || operand_equal_p (old_val->value, new_val.value, 0)))); |
0bca51f0 DN |
433 | |
434 | if (old_val->lattice_val != new_val.lattice_val) | |
6de9cd9a | 435 | { |
750628d8 DN |
436 | if (dump_file && (dump_flags & TDF_DETAILS)) |
437 | { | |
0bca51f0 | 438 | dump_lattice_value (dump_file, "Lattice value changed to ", new_val); |
106dec71 | 439 | fprintf (dump_file, ". Adding SSA edges to worklist.\n"); |
750628d8 DN |
440 | } |
441 | ||
0bca51f0 DN |
442 | *old_val = new_val; |
443 | ||
106dec71 ZD |
444 | gcc_assert (new_val.lattice_val != UNDEFINED); |
445 | return true; | |
6de9cd9a | 446 | } |
750628d8 DN |
447 | |
448 | return false; | |
6de9cd9a DN |
449 | } |
450 | ||
451 | ||
0bca51f0 | 452 | /* Return the likely CCP lattice value for STMT. |
6de9cd9a | 453 | |
750628d8 | 454 | If STMT has no operands, then return CONSTANT. |
6de9cd9a | 455 | |
7f879c96 RG |
456 | Else if undefinedness of operands of STMT cause its value to be |
457 | undefined, then return UNDEFINED. | |
6de9cd9a | 458 | |
750628d8 | 459 | Else if any operands of STMT are constants, then return CONSTANT. |
6de9cd9a | 460 | |
750628d8 | 461 | Else return VARYING. */ |
6de9cd9a | 462 | |
0bca51f0 | 463 | static ccp_lattice_t |
726a989a | 464 | likely_value (gimple stmt) |
750628d8 | 465 | { |
7f879c96 | 466 | bool has_constant_operand, has_undefined_operand, all_undefined_operands; |
750628d8 DN |
467 | tree use; |
468 | ssa_op_iter iter; | |
e8114fba | 469 | unsigned i; |
6de9cd9a | 470 | |
e0c68ce9 | 471 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
472 | |
473 | /* This function appears to be called only for assignments, calls, | |
474 | conditionals, and switches, due to the logic in visit_stmt. */ | |
475 | gcc_assert (code == GIMPLE_ASSIGN | |
476 | || code == GIMPLE_CALL | |
477 | || code == GIMPLE_COND | |
478 | || code == GIMPLE_SWITCH); | |
0bca51f0 DN |
479 | |
480 | /* If the statement has volatile operands, it won't fold to a | |
481 | constant value. */ | |
726a989a | 482 | if (gimple_has_volatile_ops (stmt)) |
0bca51f0 DN |
483 | return VARYING; |
484 | ||
726a989a | 485 | /* Arrive here for more complex cases. */ |
106dec71 | 486 | has_constant_operand = false; |
7f879c96 RG |
487 | has_undefined_operand = false; |
488 | all_undefined_operands = true; | |
e8114fba | 489 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
750628d8 | 490 | { |
106dec71 | 491 | prop_value_t *val = get_value (use); |
750628d8 | 492 | |
106dec71 | 493 | if (val->lattice_val == UNDEFINED) |
7f879c96 RG |
494 | has_undefined_operand = true; |
495 | else | |
496 | all_undefined_operands = false; | |
0bca51f0 | 497 | |
750628d8 | 498 | if (val->lattice_val == CONSTANT) |
106dec71 | 499 | has_constant_operand = true; |
6de9cd9a | 500 | } |
750628d8 | 501 | |
5006671f RG |
502 | /* There may be constants in regular rhs operands. For calls we |
503 | have to ignore lhs, fndecl and static chain, otherwise only | |
504 | the lhs. */ | |
505 | for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); | |
e8114fba RG |
506 | i < gimple_num_ops (stmt); ++i) |
507 | { | |
508 | tree op = gimple_op (stmt, i); | |
509 | if (!op || TREE_CODE (op) == SSA_NAME) | |
510 | continue; | |
511 | if (is_gimple_min_invariant (op)) | |
512 | has_constant_operand = true; | |
513 | } | |
514 | ||
1cdaa211 RG |
515 | if (has_constant_operand) |
516 | all_undefined_operands = false; | |
517 | ||
7f879c96 RG |
518 | /* If the operation combines operands like COMPLEX_EXPR make sure to |
519 | not mark the result UNDEFINED if only one part of the result is | |
520 | undefined. */ | |
726a989a | 521 | if (has_undefined_operand && all_undefined_operands) |
7f879c96 | 522 | return UNDEFINED; |
726a989a | 523 | else if (code == GIMPLE_ASSIGN && has_undefined_operand) |
7f879c96 | 524 | { |
726a989a | 525 | switch (gimple_assign_rhs_code (stmt)) |
7f879c96 RG |
526 | { |
527 | /* Unary operators are handled with all_undefined_operands. */ | |
528 | case PLUS_EXPR: | |
529 | case MINUS_EXPR: | |
7f879c96 | 530 | case POINTER_PLUS_EXPR: |
7f879c96 RG |
531 | /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. |
532 | Not bitwise operators, one VARYING operand may specify the | |
533 | result completely. Not logical operators for the same reason. | |
0cedb9e9 RG |
534 | Not COMPLEX_EXPR as one VARYING operand makes the result partly |
535 | not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
536 | the undefined operand may be promoted. */ | |
7f879c96 RG |
537 | return UNDEFINED; |
538 | ||
539 | default: | |
540 | ; | |
541 | } | |
542 | } | |
543 | /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
544 | fall back to VARYING even if there were CONSTANT operands. */ | |
545 | if (has_undefined_operand) | |
546 | return VARYING; | |
547 | ||
e8114fba RG |
548 | /* We do not consider virtual operands here -- load from read-only |
549 | memory may have only VARYING virtual operands, but still be | |
550 | constant. */ | |
106dec71 | 551 | if (has_constant_operand |
e8114fba | 552 | || gimple_references_memory_p (stmt)) |
0bca51f0 DN |
553 | return CONSTANT; |
554 | ||
106dec71 | 555 | return VARYING; |
6de9cd9a DN |
556 | } |
557 | ||
106dec71 ZD |
558 | /* Returns true if STMT cannot be constant. */ |
559 | ||
560 | static bool | |
726a989a | 561 | surely_varying_stmt_p (gimple stmt) |
106dec71 ZD |
562 | { |
563 | /* If the statement has operands that we cannot handle, it cannot be | |
564 | constant. */ | |
726a989a | 565 | if (gimple_has_volatile_ops (stmt)) |
106dec71 ZD |
566 | return true; |
567 | ||
174ef36d RG |
568 | /* If it is a call and does not return a value or is not a |
569 | builtin and not an indirect call, it is varying. */ | |
726a989a | 570 | if (is_gimple_call (stmt)) |
174ef36d RG |
571 | { |
572 | tree fndecl; | |
573 | if (!gimple_call_lhs (stmt) | |
574 | || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
99f536cc | 575 | && !DECL_BUILT_IN (fndecl))) |
174ef36d RG |
576 | return true; |
577 | } | |
106dec71 | 578 | |
e8114fba | 579 | /* Any other store operation is not interesting. */ |
5006671f | 580 | else if (gimple_vdef (stmt)) |
e8114fba RG |
581 | return true; |
582 | ||
106dec71 ZD |
583 | /* Anything other than assignments and conditional jumps are not |
584 | interesting for CCP. */ | |
726a989a | 585 | if (gimple_code (stmt) != GIMPLE_ASSIGN |
174ef36d RG |
586 | && gimple_code (stmt) != GIMPLE_COND |
587 | && gimple_code (stmt) != GIMPLE_SWITCH | |
588 | && gimple_code (stmt) != GIMPLE_CALL) | |
106dec71 ZD |
589 | return true; |
590 | ||
591 | return false; | |
592 | } | |
6de9cd9a | 593 | |
750628d8 | 594 | /* Initialize local data structures for CCP. */ |
6de9cd9a DN |
595 | |
596 | static void | |
750628d8 | 597 | ccp_initialize (void) |
6de9cd9a | 598 | { |
750628d8 | 599 | basic_block bb; |
6de9cd9a | 600 | |
b9eae1a9 | 601 | const_val = XCNEWVEC (prop_value_t, num_ssa_names); |
6de9cd9a | 602 | |
750628d8 DN |
603 | /* Initialize simulation flags for PHI nodes and statements. */ |
604 | FOR_EACH_BB (bb) | |
6de9cd9a | 605 | { |
726a989a | 606 | gimple_stmt_iterator i; |
6de9cd9a | 607 | |
726a989a | 608 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
750628d8 | 609 | { |
726a989a | 610 | gimple stmt = gsi_stmt (i); |
cd6ea7a2 RH |
611 | bool is_varying; |
612 | ||
613 | /* If the statement is a control insn, then we do not | |
614 | want to avoid simulating the statement once. Failure | |
615 | to do so means that those edges will never get added. */ | |
616 | if (stmt_ends_bb_p (stmt)) | |
617 | is_varying = false; | |
618 | else | |
619 | is_varying = surely_varying_stmt_p (stmt); | |
6de9cd9a | 620 | |
106dec71 | 621 | if (is_varying) |
750628d8 | 622 | { |
0bca51f0 DN |
623 | tree def; |
624 | ssa_op_iter iter; | |
625 | ||
626 | /* If the statement will not produce a constant, mark | |
627 | all its outputs VARYING. */ | |
628 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
e8114fba | 629 | set_value_varying (def); |
750628d8 | 630 | } |
726a989a | 631 | prop_set_simulate_again (stmt, !is_varying); |
750628d8 | 632 | } |
6de9cd9a DN |
633 | } |
634 | ||
726a989a RB |
635 | /* Now process PHI nodes. We never clear the simulate_again flag on |
636 | phi nodes, since we do not know which edges are executable yet, | |
637 | except for phi nodes for virtual operands when we do not do store ccp. */ | |
750628d8 | 638 | FOR_EACH_BB (bb) |
6de9cd9a | 639 | { |
726a989a | 640 | gimple_stmt_iterator i; |
750628d8 | 641 | |
726a989a RB |
642 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
643 | { | |
644 | gimple phi = gsi_stmt (i); | |
645 | ||
dce2b2f6 | 646 | if (!is_gimple_reg (gimple_phi_result (phi))) |
726a989a | 647 | prop_set_simulate_again (phi, false); |
106dec71 | 648 | else |
726a989a | 649 | prop_set_simulate_again (phi, true); |
750628d8 | 650 | } |
6de9cd9a | 651 | } |
750628d8 | 652 | } |
6de9cd9a | 653 | |
74fe548b XDL |
654 | /* Debug count support. Reset the values of ssa names |
655 | VARYING when the total number ssa names analyzed is | |
656 | beyond the debug count specified. */ | |
657 | ||
658 | static void | |
659 | do_dbg_cnt (void) | |
660 | { | |
661 | unsigned i; | |
662 | for (i = 0; i < num_ssa_names; i++) | |
663 | { | |
664 | if (!dbg_cnt (ccp)) | |
665 | { | |
666 | const_val[i].lattice_val = VARYING; | |
667 | const_val[i].value = NULL_TREE; | |
668 | } | |
669 | } | |
670 | } | |
671 | ||
6de9cd9a | 672 | |
0bca51f0 | 673 | /* Do final substitution of propagated values, cleanup the flowgraph and |
b8698a0f | 674 | free allocated storage. |
6de9cd9a | 675 | |
3253eafb JH |
676 | Return TRUE when something was optimized. */ |
677 | ||
678 | static bool | |
0bca51f0 | 679 | ccp_finalize (void) |
6de9cd9a | 680 | { |
74fe548b XDL |
681 | bool something_changed; |
682 | ||
683 | do_dbg_cnt (); | |
0bca51f0 | 684 | /* Perform substitutions based on the known constant values. */ |
8ab7d796 | 685 | something_changed = substitute_and_fold (const_val, ccp_fold_stmt, true); |
6de9cd9a | 686 | |
0bca51f0 | 687 | free (const_val); |
ed97ddc6 | 688 | const_val = NULL; |
3253eafb | 689 | return something_changed;; |
6de9cd9a DN |
690 | } |
691 | ||
692 | ||
0bca51f0 DN |
693 | /* Compute the meet operator between *VAL1 and *VAL2. Store the result |
694 | in VAL1. | |
695 | ||
696 | any M UNDEFINED = any | |
0bca51f0 DN |
697 | any M VARYING = VARYING |
698 | Ci M Cj = Ci if (i == j) | |
699 | Ci M Cj = VARYING if (i != j) | |
106dec71 | 700 | */ |
6de9cd9a DN |
701 | |
702 | static void | |
0bca51f0 | 703 | ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) |
6de9cd9a | 704 | { |
0bca51f0 | 705 | if (val1->lattice_val == UNDEFINED) |
6de9cd9a | 706 | { |
0bca51f0 DN |
707 | /* UNDEFINED M any = any */ |
708 | *val1 = *val2; | |
750628d8 | 709 | } |
0bca51f0 | 710 | else if (val2->lattice_val == UNDEFINED) |
195da47b | 711 | { |
0bca51f0 DN |
712 | /* any M UNDEFINED = any |
713 | Nothing to do. VAL1 already contains the value we want. */ | |
714 | ; | |
195da47b | 715 | } |
0bca51f0 DN |
716 | else if (val1->lattice_val == VARYING |
717 | || val2->lattice_val == VARYING) | |
750628d8 | 718 | { |
0bca51f0 DN |
719 | /* any M VARYING = VARYING. */ |
720 | val1->lattice_val = VARYING; | |
721 | val1->value = NULL_TREE; | |
750628d8 | 722 | } |
0bca51f0 DN |
723 | else if (val1->lattice_val == CONSTANT |
724 | && val2->lattice_val == CONSTANT | |
dce2b2f6 | 725 | && simple_cst_equal (val1->value, val2->value) == 1) |
750628d8 | 726 | { |
0bca51f0 DN |
727 | /* Ci M Cj = Ci if (i == j) |
728 | Ci M Cj = VARYING if (i != j) | |
729 | ||
730 | If these two values come from memory stores, make sure that | |
731 | they come from the same memory reference. */ | |
732 | val1->lattice_val = CONSTANT; | |
733 | val1->value = val1->value; | |
750628d8 DN |
734 | } |
735 | else | |
736 | { | |
0bca51f0 DN |
737 | /* Any other combination is VARYING. */ |
738 | val1->lattice_val = VARYING; | |
739 | val1->value = NULL_TREE; | |
750628d8 | 740 | } |
6de9cd9a DN |
741 | } |
742 | ||
743 | ||
750628d8 DN |
744 | /* Loop through the PHI_NODE's parameters for BLOCK and compare their |
745 | lattice values to determine PHI_NODE's lattice value. The value of a | |
0bca51f0 | 746 | PHI node is determined calling ccp_lattice_meet with all the arguments |
750628d8 | 747 | of the PHI node that are incoming via executable edges. */ |
6de9cd9a | 748 | |
750628d8 | 749 | static enum ssa_prop_result |
726a989a | 750 | ccp_visit_phi_node (gimple phi) |
6de9cd9a | 751 | { |
726a989a | 752 | unsigned i; |
0bca51f0 | 753 | prop_value_t *old_val, new_val; |
6de9cd9a | 754 | |
750628d8 | 755 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 756 | { |
750628d8 | 757 | fprintf (dump_file, "\nVisiting PHI node: "); |
726a989a | 758 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
6de9cd9a | 759 | } |
6de9cd9a | 760 | |
726a989a | 761 | old_val = get_value (gimple_phi_result (phi)); |
750628d8 DN |
762 | switch (old_val->lattice_val) |
763 | { | |
764 | case VARYING: | |
0bca51f0 | 765 | return SSA_PROP_VARYING; |
6de9cd9a | 766 | |
750628d8 DN |
767 | case CONSTANT: |
768 | new_val = *old_val; | |
769 | break; | |
6de9cd9a | 770 | |
750628d8 | 771 | case UNDEFINED: |
750628d8 | 772 | new_val.lattice_val = UNDEFINED; |
0bca51f0 | 773 | new_val.value = NULL_TREE; |
750628d8 | 774 | break; |
6de9cd9a | 775 | |
750628d8 | 776 | default: |
1e128c5f | 777 | gcc_unreachable (); |
750628d8 | 778 | } |
6de9cd9a | 779 | |
726a989a | 780 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
750628d8 | 781 | { |
0bca51f0 DN |
782 | /* Compute the meet operator over all the PHI arguments flowing |
783 | through executable edges. */ | |
726a989a | 784 | edge e = gimple_phi_arg_edge (phi, i); |
6de9cd9a | 785 | |
750628d8 DN |
786 | if (dump_file && (dump_flags & TDF_DETAILS)) |
787 | { | |
788 | fprintf (dump_file, | |
789 | "\n Argument #%d (%d -> %d %sexecutable)\n", | |
790 | i, e->src->index, e->dest->index, | |
791 | (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
792 | } | |
793 | ||
794 | /* If the incoming edge is executable, Compute the meet operator for | |
795 | the existing value of the PHI node and the current PHI argument. */ | |
796 | if (e->flags & EDGE_EXECUTABLE) | |
797 | { | |
726a989a | 798 | tree arg = gimple_phi_arg (phi, i)->def; |
0bca51f0 | 799 | prop_value_t arg_val; |
6de9cd9a | 800 | |
0bca51f0 | 801 | if (is_gimple_min_invariant (arg)) |
750628d8 | 802 | { |
0bca51f0 DN |
803 | arg_val.lattice_val = CONSTANT; |
804 | arg_val.value = arg; | |
750628d8 DN |
805 | } |
806 | else | |
106dec71 | 807 | arg_val = *(get_value (arg)); |
6de9cd9a | 808 | |
0bca51f0 | 809 | ccp_lattice_meet (&new_val, &arg_val); |
6de9cd9a | 810 | |
750628d8 DN |
811 | if (dump_file && (dump_flags & TDF_DETAILS)) |
812 | { | |
813 | fprintf (dump_file, "\t"); | |
0bca51f0 DN |
814 | print_generic_expr (dump_file, arg, dump_flags); |
815 | dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
750628d8 DN |
816 | fprintf (dump_file, "\n"); |
817 | } | |
6de9cd9a | 818 | |
750628d8 DN |
819 | if (new_val.lattice_val == VARYING) |
820 | break; | |
821 | } | |
822 | } | |
6de9cd9a DN |
823 | |
824 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
750628d8 DN |
825 | { |
826 | dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
827 | fprintf (dump_file, "\n\n"); | |
828 | } | |
829 | ||
106dec71 | 830 | /* Make the transition to the new value. */ |
726a989a | 831 | if (set_lattice_value (gimple_phi_result (phi), new_val)) |
750628d8 DN |
832 | { |
833 | if (new_val.lattice_val == VARYING) | |
834 | return SSA_PROP_VARYING; | |
835 | else | |
836 | return SSA_PROP_INTERESTING; | |
837 | } | |
838 | else | |
839 | return SSA_PROP_NOT_INTERESTING; | |
6de9cd9a DN |
840 | } |
841 | ||
0354c0c7 BS |
842 | /* Get operand number OPNR from the rhs of STMT. Before returning it, |
843 | simplify it to a constant if possible. */ | |
844 | ||
845 | static tree | |
846 | get_rhs_assign_op_for_ccp (gimple stmt, int opnr) | |
847 | { | |
848 | tree op = gimple_op (stmt, opnr); | |
849 | ||
850 | if (TREE_CODE (op) == SSA_NAME) | |
851 | { | |
852 | prop_value_t *val = get_value (op); | |
853 | if (val->lattice_val == CONSTANT) | |
854 | op = get_value (op)->value; | |
855 | } | |
856 | return op; | |
857 | } | |
858 | ||
750628d8 DN |
859 | /* CCP specific front-end to the non-destructive constant folding |
860 | routines. | |
6de9cd9a DN |
861 | |
862 | Attempt to simplify the RHS of STMT knowing that one or more | |
863 | operands are constants. | |
864 | ||
865 | If simplification is possible, return the simplified RHS, | |
726a989a | 866 | otherwise return the original RHS or NULL_TREE. */ |
6de9cd9a DN |
867 | |
868 | static tree | |
726a989a | 869 | ccp_fold (gimple stmt) |
6de9cd9a | 870 | { |
db3927fb | 871 | location_t loc = gimple_location (stmt); |
726a989a | 872 | switch (gimple_code (stmt)) |
0bca51f0 | 873 | { |
726a989a RB |
874 | case GIMPLE_ASSIGN: |
875 | { | |
876 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
877 | ||
878 | switch (get_gimple_rhs_class (subcode)) | |
879 | { | |
880 | case GIMPLE_SINGLE_RHS: | |
881 | { | |
882 | tree rhs = gimple_assign_rhs1 (stmt); | |
883 | enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
884 | ||
885 | if (TREE_CODE (rhs) == SSA_NAME) | |
886 | { | |
887 | /* If the RHS is an SSA_NAME, return its known constant value, | |
888 | if any. */ | |
889 | return get_value (rhs)->value; | |
890 | } | |
891 | /* Handle propagating invariant addresses into address operations. | |
892 | The folding we do here matches that in tree-ssa-forwprop.c. */ | |
893 | else if (TREE_CODE (rhs) == ADDR_EXPR) | |
894 | { | |
895 | tree *base; | |
896 | base = &TREE_OPERAND (rhs, 0); | |
897 | while (handled_component_p (*base)) | |
898 | base = &TREE_OPERAND (*base, 0); | |
70f34814 | 899 | if (TREE_CODE (*base) == MEM_REF |
726a989a RB |
900 | && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) |
901 | { | |
902 | prop_value_t *val = get_value (TREE_OPERAND (*base, 0)); | |
903 | if (val->lattice_val == CONSTANT | |
70f34814 | 904 | && TREE_CODE (val->value) == ADDR_EXPR) |
726a989a | 905 | { |
70f34814 RG |
906 | tree ret, save = *base; |
907 | tree new_base; | |
908 | new_base = fold_build2 (MEM_REF, TREE_TYPE (*base), | |
909 | unshare_expr (val->value), | |
910 | TREE_OPERAND (*base, 1)); | |
726a989a RB |
911 | /* We need to return a new tree, not modify the IL |
912 | or share parts of it. So play some tricks to | |
913 | avoid manually building it. */ | |
70f34814 | 914 | *base = new_base; |
726a989a RB |
915 | ret = unshare_expr (rhs); |
916 | recompute_tree_invariant_for_addr_expr (ret); | |
917 | *base = save; | |
918 | return ret; | |
919 | } | |
920 | } | |
921 | } | |
23977d3c RG |
922 | else if (TREE_CODE (rhs) == CONSTRUCTOR |
923 | && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE | |
924 | && (CONSTRUCTOR_NELTS (rhs) | |
925 | == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) | |
926 | { | |
927 | unsigned i; | |
928 | tree val, list; | |
929 | ||
930 | list = NULL_TREE; | |
931 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) | |
932 | { | |
933 | if (TREE_CODE (val) == SSA_NAME | |
934 | && get_value (val)->lattice_val == CONSTANT) | |
935 | val = get_value (val)->value; | |
936 | if (TREE_CODE (val) == INTEGER_CST | |
937 | || TREE_CODE (val) == REAL_CST | |
938 | || TREE_CODE (val) == FIXED_CST) | |
939 | list = tree_cons (NULL_TREE, val, list); | |
940 | else | |
941 | return NULL_TREE; | |
942 | } | |
943 | ||
944 | return build_vector (TREE_TYPE (rhs), nreverse (list)); | |
945 | } | |
6de9cd9a | 946 | |
726a989a | 947 | if (kind == tcc_reference) |
c76a1f18 | 948 | { |
4bad83f5 RG |
949 | if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR |
950 | || TREE_CODE (rhs) == REALPART_EXPR | |
951 | || TREE_CODE (rhs) == IMAGPART_EXPR) | |
c76a1f18 RG |
952 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
953 | { | |
954 | prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
955 | if (val->lattice_val == CONSTANT) | |
db3927fb AH |
956 | return fold_unary_loc (EXPR_LOCATION (rhs), |
957 | TREE_CODE (rhs), | |
c76a1f18 RG |
958 | TREE_TYPE (rhs), val->value); |
959 | } | |
70f34814 | 960 | else if (TREE_CODE (rhs) == MEM_REF |
e8114fba RG |
961 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) |
962 | { | |
963 | prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
964 | if (val->lattice_val == CONSTANT | |
70f34814 RG |
965 | && TREE_CODE (val->value) == ADDR_EXPR) |
966 | { | |
967 | tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs), | |
968 | unshare_expr (val->value), | |
969 | TREE_OPERAND (rhs, 1)); | |
970 | if (tem) | |
971 | rhs = tem; | |
972 | } | |
e8114fba | 973 | } |
c76a1f18 RG |
974 | return fold_const_aggregate_ref (rhs); |
975 | } | |
726a989a RB |
976 | else if (kind == tcc_declaration) |
977 | return get_symbol_constant_value (rhs); | |
978 | return rhs; | |
979 | } | |
b8698a0f | 980 | |
726a989a RB |
981 | case GIMPLE_UNARY_RHS: |
982 | { | |
983 | /* Handle unary operators that can appear in GIMPLE form. | |
984 | Note that we know the single operand must be a constant, | |
985 | so this should almost always return a simplified RHS. */ | |
986 | tree lhs = gimple_assign_lhs (stmt); | |
0354c0c7 | 987 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); |
726a989a RB |
988 | |
989 | /* Conversions are useless for CCP purposes if they are | |
990 | value-preserving. Thus the restrictions that | |
991 | useless_type_conversion_p places for pointer type conversions | |
992 | do not apply here. Substitution later will only substitute to | |
993 | allowed places. */ | |
1a87cf0c | 994 | if (CONVERT_EXPR_CODE_P (subcode) |
99f536cc | 995 | && POINTER_TYPE_P (TREE_TYPE (lhs)) |
70f34814 | 996 | && POINTER_TYPE_P (TREE_TYPE (op0))) |
99f536cc RG |
997 | { |
998 | tree tem; | |
70f34814 | 999 | /* Try to re-construct array references on-the-fly. */ |
99f536cc RG |
1000 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1001 | TREE_TYPE (op0)) | |
1002 | && ((tem = maybe_fold_offset_to_address | |
db3927fb | 1003 | (loc, |
c2255bc4 | 1004 | op0, integer_zero_node, TREE_TYPE (lhs))) |
99f536cc RG |
1005 | != NULL_TREE)) |
1006 | return tem; | |
1007 | return op0; | |
1008 | } | |
726a989a | 1009 | |
b8698a0f | 1010 | return |
db3927fb AH |
1011 | fold_unary_ignore_overflow_loc (loc, subcode, |
1012 | gimple_expr_type (stmt), op0); | |
ff8b183b | 1013 | } |
726a989a RB |
1014 | |
1015 | case GIMPLE_BINARY_RHS: | |
1016 | { | |
1017 | /* Handle binary operators that can appear in GIMPLE form. */ | |
0354c0c7 BS |
1018 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); |
1019 | tree op1 = get_rhs_assign_op_for_ccp (stmt, 2); | |
726a989a | 1020 | |
70f34814 RG |
1021 | /* Translate &x + CST into an invariant form suitable for |
1022 | further propagation. */ | |
99f536cc RG |
1023 | if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
1024 | && TREE_CODE (op0) == ADDR_EXPR | |
1025 | && TREE_CODE (op1) == INTEGER_CST) | |
1026 | { | |
70f34814 RG |
1027 | tree off = fold_convert (ptr_type_node, op1); |
1028 | return build_fold_addr_expr | |
1029 | (fold_build2 (MEM_REF, | |
1030 | TREE_TYPE (TREE_TYPE (op0)), | |
1031 | unshare_expr (op0), off)); | |
99f536cc RG |
1032 | } |
1033 | ||
db3927fb | 1034 | return fold_binary_loc (loc, subcode, |
70f34814 | 1035 | gimple_expr_type (stmt), op0, op1); |
726a989a RB |
1036 | } |
1037 | ||
0354c0c7 BS |
1038 | case GIMPLE_TERNARY_RHS: |
1039 | { | |
1040 | /* Handle binary operators that can appear in GIMPLE form. */ | |
1041 | tree op0 = get_rhs_assign_op_for_ccp (stmt, 1); | |
1042 | tree op1 = get_rhs_assign_op_for_ccp (stmt, 2); | |
1043 | tree op2 = get_rhs_assign_op_for_ccp (stmt, 3); | |
1044 | ||
1045 | return fold_ternary_loc (loc, subcode, | |
1046 | gimple_expr_type (stmt), op0, op1, op2); | |
1047 | } | |
1048 | ||
726a989a RB |
1049 | default: |
1050 | gcc_unreachable (); | |
1051 | } | |
1052 | } | |
1053 | break; | |
6de9cd9a | 1054 | |
726a989a | 1055 | case GIMPLE_CALL: |
174ef36d RG |
1056 | { |
1057 | tree fn = gimple_call_fn (stmt); | |
1058 | prop_value_t *val; | |
1059 | ||
1060 | if (TREE_CODE (fn) == SSA_NAME) | |
1061 | { | |
1062 | val = get_value (fn); | |
1063 | if (val->lattice_val == CONSTANT) | |
1064 | fn = val->value; | |
1065 | } | |
1066 | if (TREE_CODE (fn) == ADDR_EXPR | |
a135b1c4 | 1067 | && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL |
174ef36d RG |
1068 | && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) |
1069 | { | |
1070 | tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
1071 | tree call, retval; | |
1072 | unsigned i; | |
1073 | for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
1074 | { | |
1075 | args[i] = gimple_call_arg (stmt, i); | |
1076 | if (TREE_CODE (args[i]) == SSA_NAME) | |
1077 | { | |
1078 | val = get_value (args[i]); | |
1079 | if (val->lattice_val == CONSTANT) | |
1080 | args[i] = val->value; | |
1081 | } | |
1082 | } | |
db3927fb AH |
1083 | call = build_call_array_loc (loc, |
1084 | gimple_call_return_type (stmt), | |
1085 | fn, gimple_call_num_args (stmt), args); | |
1086 | retval = fold_call_expr (EXPR_LOCATION (call), call, false); | |
174ef36d RG |
1087 | if (retval) |
1088 | /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
1089 | STRIP_NOPS (retval); | |
1090 | return retval; | |
1091 | } | |
1092 | return NULL_TREE; | |
1093 | } | |
6de9cd9a | 1094 | |
726a989a RB |
1095 | case GIMPLE_COND: |
1096 | { | |
1097 | /* Handle comparison operators that can appear in GIMPLE form. */ | |
1098 | tree op0 = gimple_cond_lhs (stmt); | |
1099 | tree op1 = gimple_cond_rhs (stmt); | |
1100 | enum tree_code code = gimple_cond_code (stmt); | |
1101 | ||
1102 | /* Simplify the operands down to constants when appropriate. */ | |
1103 | if (TREE_CODE (op0) == SSA_NAME) | |
1104 | { | |
1105 | prop_value_t *val = get_value (op0); | |
1106 | if (val->lattice_val == CONSTANT) | |
1107 | op0 = val->value; | |
1108 | } | |
1109 | ||
1110 | if (TREE_CODE (op1) == SSA_NAME) | |
1111 | { | |
1112 | prop_value_t *val = get_value (op1); | |
1113 | if (val->lattice_val == CONSTANT) | |
1114 | op1 = val->value; | |
1115 | } | |
1116 | ||
db3927fb | 1117 | return fold_binary_loc (loc, code, boolean_type_node, op0, op1); |
726a989a | 1118 | } |
6de9cd9a | 1119 | |
726a989a RB |
1120 | case GIMPLE_SWITCH: |
1121 | { | |
1122 | tree rhs = gimple_switch_index (stmt); | |
87e1e42b | 1123 | |
726a989a RB |
1124 | if (TREE_CODE (rhs) == SSA_NAME) |
1125 | { | |
1126 | /* If the RHS is an SSA_NAME, return its known constant value, | |
1127 | if any. */ | |
1128 | return get_value (rhs)->value; | |
1129 | } | |
87e1e42b | 1130 | |
726a989a RB |
1131 | return rhs; |
1132 | } | |
00d382a8 | 1133 | |
726a989a RB |
1134 | default: |
1135 | gcc_unreachable (); | |
6de9cd9a | 1136 | } |
6de9cd9a DN |
1137 | } |
1138 | ||
1139 | ||
ae3df618 SB |
1140 | /* Return the tree representing the element referenced by T if T is an |
1141 | ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
1142 | NULL_TREE otherwise. */ | |
1143 | ||
ed97ddc6 | 1144 | tree |
ae3df618 SB |
1145 | fold_const_aggregate_ref (tree t) |
1146 | { | |
1147 | prop_value_t *value; | |
4038c495 GB |
1148 | tree base, ctor, idx, field; |
1149 | unsigned HOST_WIDE_INT cnt; | |
1150 | tree cfield, cval; | |
ae3df618 | 1151 | |
e8114fba RG |
1152 | if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration) |
1153 | return get_symbol_constant_value (t); | |
1154 | ||
ae3df618 SB |
1155 | switch (TREE_CODE (t)) |
1156 | { | |
1157 | case ARRAY_REF: | |
1158 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1159 | DECL_INITIAL. If BASE is a nested reference into another | |
1160 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1161 | the inner reference. */ | |
1162 | base = TREE_OPERAND (t, 0); | |
1163 | switch (TREE_CODE (base)) | |
1164 | { | |
1165 | case VAR_DECL: | |
1166 | if (!TREE_READONLY (base) | |
1167 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1168 | || !targetm.binds_local_p (base)) | |
1169 | return NULL_TREE; | |
1170 | ||
1171 | ctor = DECL_INITIAL (base); | |
1172 | break; | |
1173 | ||
1174 | case ARRAY_REF: | |
1175 | case COMPONENT_REF: | |
1176 | ctor = fold_const_aggregate_ref (base); | |
1177 | break; | |
1178 | ||
87e1e42b RG |
1179 | case STRING_CST: |
1180 | case CONSTRUCTOR: | |
1181 | ctor = base; | |
1182 | break; | |
1183 | ||
ae3df618 SB |
1184 | default: |
1185 | return NULL_TREE; | |
1186 | } | |
1187 | ||
1188 | if (ctor == NULL_TREE | |
faaf1436 RG |
1189 | || (TREE_CODE (ctor) != CONSTRUCTOR |
1190 | && TREE_CODE (ctor) != STRING_CST) | |
ae3df618 SB |
1191 | || !TREE_STATIC (ctor)) |
1192 | return NULL_TREE; | |
1193 | ||
1194 | /* Get the index. If we have an SSA_NAME, try to resolve it | |
1195 | with the current lattice value for the SSA_NAME. */ | |
1196 | idx = TREE_OPERAND (t, 1); | |
1197 | switch (TREE_CODE (idx)) | |
1198 | { | |
1199 | case SSA_NAME: | |
106dec71 | 1200 | if ((value = get_value (idx)) |
ae3df618 SB |
1201 | && value->lattice_val == CONSTANT |
1202 | && TREE_CODE (value->value) == INTEGER_CST) | |
1203 | idx = value->value; | |
1204 | else | |
1205 | return NULL_TREE; | |
1206 | break; | |
1207 | ||
1208 | case INTEGER_CST: | |
1209 | break; | |
1210 | ||
1211 | default: | |
1212 | return NULL_TREE; | |
1213 | } | |
1214 | ||
faaf1436 RG |
1215 | /* Fold read from constant string. */ |
1216 | if (TREE_CODE (ctor) == STRING_CST) | |
1217 | { | |
1218 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1219 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1220 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1221 | == MODE_INT) | |
1222 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1223 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
0c4d4efb DJ |
1224 | return build_int_cst_type (TREE_TYPE (t), |
1225 | (TREE_STRING_POINTER (ctor) | |
1226 | [TREE_INT_CST_LOW (idx)])); | |
faaf1436 RG |
1227 | return NULL_TREE; |
1228 | } | |
1229 | ||
ae3df618 | 1230 | /* Whoo-hoo! I'll fold ya baby. Yeah! */ |
4038c495 GB |
1231 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1232 | if (tree_int_cst_equal (cfield, idx)) | |
62bc00e2 | 1233 | { |
5c95f07b | 1234 | STRIP_NOPS (cval); |
75ccc1e7 RG |
1235 | if (TREE_CODE (cval) == ADDR_EXPR) |
1236 | { | |
1237 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1238 | if (base && TREE_CODE (base) == VAR_DECL) | |
1239 | add_referenced_var (base); | |
1240 | } | |
62bc00e2 RG |
1241 | return cval; |
1242 | } | |
ae3df618 SB |
1243 | break; |
1244 | ||
1245 | case COMPONENT_REF: | |
1246 | /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
1247 | DECL_INITIAL. If BASE is a nested reference into another | |
1248 | ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
1249 | the inner reference. */ | |
1250 | base = TREE_OPERAND (t, 0); | |
1251 | switch (TREE_CODE (base)) | |
1252 | { | |
1253 | case VAR_DECL: | |
1254 | if (!TREE_READONLY (base) | |
1255 | || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
1256 | || !targetm.binds_local_p (base)) | |
1257 | return NULL_TREE; | |
1258 | ||
1259 | ctor = DECL_INITIAL (base); | |
1260 | break; | |
1261 | ||
1262 | case ARRAY_REF: | |
1263 | case COMPONENT_REF: | |
1264 | ctor = fold_const_aggregate_ref (base); | |
1265 | break; | |
1266 | ||
1267 | default: | |
1268 | return NULL_TREE; | |
1269 | } | |
1270 | ||
1271 | if (ctor == NULL_TREE | |
1272 | || TREE_CODE (ctor) != CONSTRUCTOR | |
1273 | || !TREE_STATIC (ctor)) | |
1274 | return NULL_TREE; | |
1275 | ||
1276 | field = TREE_OPERAND (t, 1); | |
1277 | ||
4038c495 GB |
1278 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) |
1279 | if (cfield == field | |
ae3df618 | 1280 | /* FIXME: Handle bit-fields. */ |
4038c495 | 1281 | && ! DECL_BIT_FIELD (cfield)) |
62bc00e2 | 1282 | { |
5c95f07b | 1283 | STRIP_NOPS (cval); |
75ccc1e7 RG |
1284 | if (TREE_CODE (cval) == ADDR_EXPR) |
1285 | { | |
1286 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1287 | if (base && TREE_CODE (base) == VAR_DECL) | |
1288 | add_referenced_var (base); | |
1289 | } | |
62bc00e2 RG |
1290 | return cval; |
1291 | } | |
ae3df618 SB |
1292 | break; |
1293 | ||
1ebd8d9a SB |
1294 | case REALPART_EXPR: |
1295 | case IMAGPART_EXPR: | |
1296 | { | |
1297 | tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
1298 | if (c && TREE_CODE (c) == COMPLEX_CST) | |
db3927fb AH |
1299 | return fold_build1_loc (EXPR_LOCATION (t), |
1300 | TREE_CODE (t), TREE_TYPE (t), c); | |
1ebd8d9a SB |
1301 | break; |
1302 | } | |
87e1e42b | 1303 | |
70f34814 RG |
1304 | case MEM_REF: |
1305 | /* Get the base object we are accessing. */ | |
1306 | base = TREE_OPERAND (t, 0); | |
1307 | if (TREE_CODE (base) == SSA_NAME | |
1308 | && (value = get_value (base)) | |
1309 | && value->lattice_val == CONSTANT) | |
1310 | base = value->value; | |
1311 | if (TREE_CODE (base) != ADDR_EXPR) | |
1312 | return NULL_TREE; | |
1313 | base = TREE_OPERAND (base, 0); | |
1314 | switch (TREE_CODE (base)) | |
1315 | { | |
1316 | case VAR_DECL: | |
1317 | if (DECL_P (base) | |
1318 | && !AGGREGATE_TYPE_P (TREE_TYPE (base)) | |
1319 | && integer_zerop (TREE_OPERAND (t, 1))) | |
3fa39831 RG |
1320 | { |
1321 | tree res = get_symbol_constant_value (base); | |
1322 | if (res | |
1323 | && !useless_type_conversion_p | |
1324 | (TREE_TYPE (t), TREE_TYPE (res))) | |
1325 | res = fold_unary (VIEW_CONVERT_EXPR, TREE_TYPE (t), res); | |
1326 | return res; | |
1327 | } | |
70f34814 RG |
1328 | |
1329 | if (!TREE_READONLY (base) | |
1330 | || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
1331 | || !targetm.binds_local_p (base)) | |
1332 | return NULL_TREE; | |
1333 | ||
1334 | ctor = DECL_INITIAL (base); | |
1335 | break; | |
1336 | ||
1337 | case STRING_CST: | |
1338 | case CONSTRUCTOR: | |
1339 | ctor = base; | |
1340 | break; | |
1341 | ||
1342 | default: | |
1343 | return NULL_TREE; | |
1344 | } | |
1345 | ||
1346 | if (ctor == NULL_TREE | |
1347 | || (TREE_CODE (ctor) != CONSTRUCTOR | |
1348 | && TREE_CODE (ctor) != STRING_CST) | |
1349 | || !TREE_STATIC (ctor)) | |
1350 | return NULL_TREE; | |
1351 | ||
1352 | /* Get the byte offset. */ | |
1353 | idx = TREE_OPERAND (t, 1); | |
1354 | ||
1355 | /* Fold read from constant string. */ | |
1356 | if (TREE_CODE (ctor) == STRING_CST) | |
1357 | { | |
1358 | if ((TYPE_MODE (TREE_TYPE (t)) | |
1359 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1360 | && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1361 | == MODE_INT) | |
1362 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
1363 | && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
1364 | return build_int_cst_type (TREE_TYPE (t), | |
1365 | (TREE_STRING_POINTER (ctor) | |
1366 | [TREE_INT_CST_LOW (idx)])); | |
1367 | return NULL_TREE; | |
1368 | } | |
1369 | ||
1370 | /* ??? Implement byte-offset indexing into a non-array CONSTRUCTOR. */ | |
1371 | if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE | |
1372 | && (TYPE_MODE (TREE_TYPE (t)) | |
1373 | == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
1374 | && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (t))) != 0 | |
1375 | && integer_zerop | |
1376 | (int_const_binop | |
1377 | (TRUNC_MOD_EXPR, idx, | |
1378 | size_int (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (t)))), 0))) | |
1379 | { | |
1380 | idx = int_const_binop (TRUNC_DIV_EXPR, idx, | |
1381 | size_int (GET_MODE_SIZE | |
1382 | (TYPE_MODE (TREE_TYPE (t)))), 0); | |
1383 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
1384 | if (tree_int_cst_equal (cfield, idx)) | |
1385 | { | |
1386 | STRIP_NOPS (cval); | |
1387 | if (TREE_CODE (cval) == ADDR_EXPR) | |
1388 | { | |
1389 | tree base = get_base_address (TREE_OPERAND (cval, 0)); | |
1390 | if (base && TREE_CODE (base) == VAR_DECL) | |
1391 | add_referenced_var (base); | |
1392 | } | |
1393 | if (useless_type_conversion_p (TREE_TYPE (t), TREE_TYPE (cval))) | |
1394 | return cval; | |
1395 | else if (CONSTANT_CLASS_P (cval)) | |
1396 | return fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (t), cval); | |
1397 | else | |
1398 | return NULL_TREE; | |
1399 | } | |
1400 | } | |
1401 | break; | |
87e1e42b | 1402 | |
ae3df618 SB |
1403 | default: |
1404 | break; | |
1405 | } | |
1406 | ||
1407 | return NULL_TREE; | |
1408 | } | |
726a989a RB |
1409 | |
1410 | /* Evaluate statement STMT. | |
1411 | Valid only for assignments, calls, conditionals, and switches. */ | |
6de9cd9a | 1412 | |
0bca51f0 | 1413 | static prop_value_t |
726a989a | 1414 | evaluate_stmt (gimple stmt) |
6de9cd9a | 1415 | { |
0bca51f0 | 1416 | prop_value_t val; |
faaf1436 | 1417 | tree simplified = NULL_TREE; |
0bca51f0 | 1418 | ccp_lattice_t likelyvalue = likely_value (stmt); |
6ac01510 | 1419 | bool is_constant; |
0bca51f0 | 1420 | |
6ac01510 ILT |
1421 | fold_defer_overflow_warnings (); |
1422 | ||
6de9cd9a DN |
1423 | /* If the statement is likely to have a CONSTANT result, then try |
1424 | to fold the statement to determine the constant value. */ | |
726a989a RB |
1425 | /* FIXME. This is the only place that we call ccp_fold. |
1426 | Since likely_value never returns CONSTANT for calls, we will | |
1427 | not attempt to fold them, including builtins that may profit. */ | |
6de9cd9a DN |
1428 | if (likelyvalue == CONSTANT) |
1429 | simplified = ccp_fold (stmt); | |
1430 | /* If the statement is likely to have a VARYING result, then do not | |
1431 | bother folding the statement. */ | |
87e1e42b | 1432 | else if (likelyvalue == VARYING) |
726a989a | 1433 | { |
e0c68ce9 | 1434 | enum gimple_code code = gimple_code (stmt); |
726a989a RB |
1435 | if (code == GIMPLE_ASSIGN) |
1436 | { | |
1437 | enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
b8698a0f | 1438 | |
726a989a RB |
1439 | /* Other cases cannot satisfy is_gimple_min_invariant |
1440 | without folding. */ | |
1441 | if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
1442 | simplified = gimple_assign_rhs1 (stmt); | |
1443 | } | |
1444 | else if (code == GIMPLE_SWITCH) | |
1445 | simplified = gimple_switch_index (stmt); | |
1446 | else | |
44e10129 MM |
1447 | /* These cannot satisfy is_gimple_min_invariant without folding. */ |
1448 | gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
726a989a | 1449 | } |
6de9cd9a | 1450 | |
6ac01510 ILT |
1451 | is_constant = simplified && is_gimple_min_invariant (simplified); |
1452 | ||
1453 | fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
1454 | ||
00d382a8 RG |
1455 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1456 | { | |
1457 | fprintf (dump_file, "which is likely "); | |
1458 | switch (likelyvalue) | |
1459 | { | |
1460 | case CONSTANT: | |
1461 | fprintf (dump_file, "CONSTANT"); | |
1462 | break; | |
1463 | case UNDEFINED: | |
1464 | fprintf (dump_file, "UNDEFINED"); | |
1465 | break; | |
1466 | case VARYING: | |
1467 | fprintf (dump_file, "VARYING"); | |
1468 | break; | |
1469 | default:; | |
1470 | } | |
1471 | fprintf (dump_file, "\n"); | |
1472 | } | |
1473 | ||
6ac01510 | 1474 | if (is_constant) |
6de9cd9a DN |
1475 | { |
1476 | /* The statement produced a constant value. */ | |
1477 | val.lattice_val = CONSTANT; | |
0bca51f0 | 1478 | val.value = simplified; |
6de9cd9a DN |
1479 | } |
1480 | else | |
1481 | { | |
1482 | /* The statement produced a nonconstant value. If the statement | |
0bca51f0 DN |
1483 | had UNDEFINED operands, then the result of the statement |
1484 | should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
106dec71 | 1485 | if (likelyvalue == UNDEFINED) |
a318e3ac SB |
1486 | val.lattice_val = likelyvalue; |
1487 | else | |
1488 | val.lattice_val = VARYING; | |
1489 | ||
0bca51f0 | 1490 | val.value = NULL_TREE; |
6de9cd9a | 1491 | } |
750628d8 DN |
1492 | |
1493 | return val; | |
6de9cd9a DN |
1494 | } |
1495 | ||
f61e18ec RG |
1496 | /* Fold the stmt at *GSI with CCP specific information that propagating |
1497 | and regular folding does not catch. */ | |
1498 | ||
1499 | static bool | |
1500 | ccp_fold_stmt (gimple_stmt_iterator *gsi) | |
1501 | { | |
1502 | gimple stmt = gsi_stmt (*gsi); | |
f61e18ec | 1503 | |
830bc550 RG |
1504 | switch (gimple_code (stmt)) |
1505 | { | |
1506 | case GIMPLE_COND: | |
1507 | { | |
1508 | prop_value_t val; | |
1509 | /* Statement evaluation will handle type mismatches in constants | |
1510 | more gracefully than the final propagation. This allows us to | |
1511 | fold more conditionals here. */ | |
1512 | val = evaluate_stmt (stmt); | |
1513 | if (val.lattice_val != CONSTANT | |
1514 | || TREE_CODE (val.value) != INTEGER_CST) | |
1515 | return false; | |
1516 | ||
1517 | if (integer_zerop (val.value)) | |
1518 | gimple_cond_make_false (stmt); | |
1519 | else | |
1520 | gimple_cond_make_true (stmt); | |
f61e18ec | 1521 | |
830bc550 RG |
1522 | return true; |
1523 | } | |
f61e18ec | 1524 | |
830bc550 RG |
1525 | case GIMPLE_CALL: |
1526 | { | |
1527 | tree lhs = gimple_call_lhs (stmt); | |
1528 | prop_value_t *val; | |
1529 | tree argt; | |
1530 | bool changed = false; | |
1531 | unsigned i; | |
1532 | ||
1533 | /* If the call was folded into a constant make sure it goes | |
1534 | away even if we cannot propagate into all uses because of | |
1535 | type issues. */ | |
1536 | if (lhs | |
1537 | && TREE_CODE (lhs) == SSA_NAME | |
1538 | && (val = get_value (lhs)) | |
1539 | && val->lattice_val == CONSTANT) | |
1540 | { | |
eb6b98c7 RG |
1541 | tree new_rhs = unshare_expr (val->value); |
1542 | bool res; | |
830bc550 RG |
1543 | if (!useless_type_conversion_p (TREE_TYPE (lhs), |
1544 | TREE_TYPE (new_rhs))) | |
1545 | new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); | |
eb6b98c7 RG |
1546 | res = update_call_from_tree (gsi, new_rhs); |
1547 | gcc_assert (res); | |
830bc550 RG |
1548 | return true; |
1549 | } | |
1550 | ||
1551 | /* Propagate into the call arguments. Compared to replace_uses_in | |
1552 | this can use the argument slot types for type verification | |
1553 | instead of the current argument type. We also can safely | |
1554 | drop qualifiers here as we are dealing with constants anyway. */ | |
1555 | argt = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt)))); | |
1556 | for (i = 0; i < gimple_call_num_args (stmt) && argt; | |
1557 | ++i, argt = TREE_CHAIN (argt)) | |
1558 | { | |
1559 | tree arg = gimple_call_arg (stmt, i); | |
1560 | if (TREE_CODE (arg) == SSA_NAME | |
1561 | && (val = get_value (arg)) | |
1562 | && val->lattice_val == CONSTANT | |
1563 | && useless_type_conversion_p | |
1564 | (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), | |
1565 | TYPE_MAIN_VARIANT (TREE_TYPE (val->value)))) | |
1566 | { | |
eb6b98c7 | 1567 | gimple_call_set_arg (stmt, i, unshare_expr (val->value)); |
830bc550 RG |
1568 | changed = true; |
1569 | } | |
1570 | } | |
1571 | ||
1572 | return changed; | |
1573 | } | |
f61e18ec | 1574 | |
5c95f07b RG |
1575 | case GIMPLE_ASSIGN: |
1576 | { | |
1577 | tree lhs = gimple_assign_lhs (stmt); | |
1578 | prop_value_t *val; | |
1579 | ||
1580 | /* If we have a load that turned out to be constant replace it | |
1581 | as we cannot propagate into all uses in all cases. */ | |
1582 | if (gimple_assign_single_p (stmt) | |
1583 | && TREE_CODE (lhs) == SSA_NAME | |
1584 | && (val = get_value (lhs)) | |
1585 | && val->lattice_val == CONSTANT) | |
1586 | { | |
1587 | tree rhs = unshare_expr (val->value); | |
1588 | if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) | |
70f34814 | 1589 | rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); |
5c95f07b RG |
1590 | gimple_assign_set_rhs_from_tree (gsi, rhs); |
1591 | return true; | |
1592 | } | |
1593 | ||
1594 | return false; | |
1595 | } | |
1596 | ||
830bc550 RG |
1597 | default: |
1598 | return false; | |
1599 | } | |
f61e18ec RG |
1600 | } |
1601 | ||
750628d8 | 1602 | /* Visit the assignment statement STMT. Set the value of its LHS to the |
0bca51f0 DN |
1603 | value computed by the RHS and store LHS in *OUTPUT_P. If STMT |
1604 | creates virtual definitions, set the value of each new name to that | |
726a989a RB |
1605 | of the RHS (if we can derive a constant out of the RHS). |
1606 | Value-returning call statements also perform an assignment, and | |
1607 | are handled here. */ | |
6de9cd9a | 1608 | |
750628d8 | 1609 | static enum ssa_prop_result |
726a989a | 1610 | visit_assignment (gimple stmt, tree *output_p) |
6de9cd9a | 1611 | { |
0bca51f0 | 1612 | prop_value_t val; |
0bca51f0 | 1613 | enum ssa_prop_result retval; |
6de9cd9a | 1614 | |
726a989a | 1615 | tree lhs = gimple_get_lhs (stmt); |
6de9cd9a | 1616 | |
726a989a RB |
1617 | gcc_assert (gimple_code (stmt) != GIMPLE_CALL |
1618 | || gimple_call_lhs (stmt) != NULL_TREE); | |
1619 | ||
1620 | if (gimple_assign_copy_p (stmt)) | |
750628d8 | 1621 | { |
726a989a | 1622 | tree rhs = gimple_assign_rhs1 (stmt); |
0bca51f0 | 1623 | |
726a989a RB |
1624 | if (TREE_CODE (rhs) == SSA_NAME) |
1625 | { | |
1626 | /* For a simple copy operation, we copy the lattice values. */ | |
1627 | prop_value_t *nval = get_value (rhs); | |
1628 | val = *nval; | |
1629 | } | |
0bca51f0 | 1630 | else |
726a989a | 1631 | val = evaluate_stmt (stmt); |
750628d8 DN |
1632 | } |
1633 | else | |
726a989a RB |
1634 | /* Evaluate the statement, which could be |
1635 | either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
87e1e42b | 1636 | val = evaluate_stmt (stmt); |
6de9cd9a | 1637 | |
0bca51f0 | 1638 | retval = SSA_PROP_NOT_INTERESTING; |
6de9cd9a | 1639 | |
750628d8 | 1640 | /* Set the lattice value of the statement's output. */ |
0bca51f0 | 1641 | if (TREE_CODE (lhs) == SSA_NAME) |
6de9cd9a | 1642 | { |
0bca51f0 DN |
1643 | /* If STMT is an assignment to an SSA_NAME, we only have one |
1644 | value to set. */ | |
1645 | if (set_lattice_value (lhs, val)) | |
1646 | { | |
1647 | *output_p = lhs; | |
1648 | if (val.lattice_val == VARYING) | |
1649 | retval = SSA_PROP_VARYING; | |
1650 | else | |
1651 | retval = SSA_PROP_INTERESTING; | |
1652 | } | |
6de9cd9a | 1653 | } |
0bca51f0 DN |
1654 | |
1655 | return retval; | |
6de9cd9a DN |
1656 | } |
1657 | ||
6de9cd9a | 1658 | |
750628d8 DN |
1659 | /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING |
1660 | if it can determine which edge will be taken. Otherwise, return | |
1661 | SSA_PROP_VARYING. */ | |
1662 | ||
1663 | static enum ssa_prop_result | |
726a989a | 1664 | visit_cond_stmt (gimple stmt, edge *taken_edge_p) |
6de9cd9a | 1665 | { |
0bca51f0 | 1666 | prop_value_t val; |
750628d8 DN |
1667 | basic_block block; |
1668 | ||
726a989a | 1669 | block = gimple_bb (stmt); |
750628d8 DN |
1670 | val = evaluate_stmt (stmt); |
1671 | ||
1672 | /* Find which edge out of the conditional block will be taken and add it | |
1673 | to the worklist. If no single edge can be determined statically, | |
1674 | return SSA_PROP_VARYING to feed all the outgoing edges to the | |
1675 | propagation engine. */ | |
0bca51f0 | 1676 | *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; |
750628d8 DN |
1677 | if (*taken_edge_p) |
1678 | return SSA_PROP_INTERESTING; | |
1679 | else | |
1680 | return SSA_PROP_VARYING; | |
6de9cd9a DN |
1681 | } |
1682 | ||
6de9cd9a | 1683 | |
750628d8 DN |
1684 | /* Evaluate statement STMT. If the statement produces an output value and |
1685 | its evaluation changes the lattice value of its output, return | |
1686 | SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
1687 | output value. | |
b8698a0f | 1688 | |
750628d8 DN |
1689 | If STMT is a conditional branch and we can determine its truth |
1690 | value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
1691 | value, return SSA_PROP_VARYING. */ | |
6de9cd9a | 1692 | |
750628d8 | 1693 | static enum ssa_prop_result |
726a989a | 1694 | ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) |
750628d8 | 1695 | { |
750628d8 DN |
1696 | tree def; |
1697 | ssa_op_iter iter; | |
6de9cd9a | 1698 | |
750628d8 | 1699 | if (dump_file && (dump_flags & TDF_DETAILS)) |
6de9cd9a | 1700 | { |
0bca51f0 | 1701 | fprintf (dump_file, "\nVisiting statement:\n"); |
726a989a | 1702 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a | 1703 | } |
6de9cd9a | 1704 | |
726a989a | 1705 | switch (gimple_code (stmt)) |
6de9cd9a | 1706 | { |
726a989a RB |
1707 | case GIMPLE_ASSIGN: |
1708 | /* If the statement is an assignment that produces a single | |
1709 | output value, evaluate its RHS to see if the lattice value of | |
1710 | its output has changed. */ | |
1711 | return visit_assignment (stmt, output_p); | |
1712 | ||
1713 | case GIMPLE_CALL: | |
1714 | /* A value-returning call also performs an assignment. */ | |
1715 | if (gimple_call_lhs (stmt) != NULL_TREE) | |
1716 | return visit_assignment (stmt, output_p); | |
1717 | break; | |
1718 | ||
1719 | case GIMPLE_COND: | |
1720 | case GIMPLE_SWITCH: | |
1721 | /* If STMT is a conditional branch, see if we can determine | |
1722 | which branch will be taken. */ | |
1723 | /* FIXME. It appears that we should be able to optimize | |
1724 | computed GOTOs here as well. */ | |
1725 | return visit_cond_stmt (stmt, taken_edge_p); | |
1726 | ||
1727 | default: | |
1728 | break; | |
6de9cd9a | 1729 | } |
6de9cd9a | 1730 | |
750628d8 DN |
1731 | /* Any other kind of statement is not interesting for constant |
1732 | propagation and, therefore, not worth simulating. */ | |
750628d8 DN |
1733 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1734 | fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
6de9cd9a | 1735 | |
750628d8 DN |
1736 | /* Definitions made by statements other than assignments to |
1737 | SSA_NAMEs represent unknown modifications to their outputs. | |
1738 | Mark them VARYING. */ | |
0bca51f0 DN |
1739 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
1740 | { | |
dce2b2f6 | 1741 | prop_value_t v = { VARYING, NULL_TREE }; |
0bca51f0 DN |
1742 | set_lattice_value (def, v); |
1743 | } | |
6de9cd9a | 1744 | |
750628d8 DN |
1745 | return SSA_PROP_VARYING; |
1746 | } | |
6de9cd9a | 1747 | |
6de9cd9a | 1748 | |
0bca51f0 | 1749 | /* Main entry point for SSA Conditional Constant Propagation. */ |
750628d8 | 1750 | |
3253eafb | 1751 | static unsigned int |
dce2b2f6 | 1752 | do_ssa_ccp (void) |
750628d8 DN |
1753 | { |
1754 | ccp_initialize (); | |
1755 | ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
3253eafb | 1756 | if (ccp_finalize ()) |
706ca88e | 1757 | return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); |
3253eafb JH |
1758 | else |
1759 | return 0; | |
6de9cd9a DN |
1760 | } |
1761 | ||
173b818d BB |
1762 | |
1763 | static bool | |
750628d8 | 1764 | gate_ccp (void) |
173b818d | 1765 | { |
750628d8 | 1766 | return flag_tree_ccp != 0; |
173b818d BB |
1767 | } |
1768 | ||
6de9cd9a | 1769 | |
b8698a0f | 1770 | struct gimple_opt_pass pass_ccp = |
750628d8 | 1771 | { |
8ddbbcae JH |
1772 | { |
1773 | GIMPLE_PASS, | |
750628d8 DN |
1774 | "ccp", /* name */ |
1775 | gate_ccp, /* gate */ | |
0bca51f0 | 1776 | do_ssa_ccp, /* execute */ |
750628d8 DN |
1777 | NULL, /* sub */ |
1778 | NULL, /* next */ | |
1779 | 0, /* static_pass_number */ | |
1780 | TV_TREE_CCP, /* tv_id */ | |
7faade0f | 1781 | PROP_cfg | PROP_ssa, /* properties_required */ |
750628d8 | 1782 | 0, /* properties_provided */ |
ae07b463 | 1783 | 0, /* properties_destroyed */ |
750628d8 | 1784 | 0, /* todo_flags_start */ |
3253eafb | 1785 | TODO_dump_func | TODO_verify_ssa |
8ddbbcae JH |
1786 | | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ |
1787 | } | |
750628d8 | 1788 | }; |
6de9cd9a | 1789 | |
6de9cd9a | 1790 | |
726a989a | 1791 | |
cb8e078d JJ |
1792 | /* Try to optimize out __builtin_stack_restore. Optimize it out |
1793 | if there is another __builtin_stack_restore in the same basic | |
1794 | block and no calls or ASM_EXPRs are in between, or if this block's | |
1795 | only outgoing edge is to EXIT_BLOCK and there are no calls or | |
1796 | ASM_EXPRs after this __builtin_stack_restore. */ | |
1797 | ||
1798 | static tree | |
726a989a | 1799 | optimize_stack_restore (gimple_stmt_iterator i) |
cb8e078d | 1800 | { |
ff9d1adc RH |
1801 | tree callee; |
1802 | gimple stmt; | |
726a989a RB |
1803 | |
1804 | basic_block bb = gsi_bb (i); | |
1805 | gimple call = gsi_stmt (i); | |
cb8e078d | 1806 | |
726a989a RB |
1807 | if (gimple_code (call) != GIMPLE_CALL |
1808 | || gimple_call_num_args (call) != 1 | |
1809 | || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
1810 | || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
cb8e078d JJ |
1811 | return NULL_TREE; |
1812 | ||
726a989a | 1813 | for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) |
cb8e078d | 1814 | { |
726a989a RB |
1815 | stmt = gsi_stmt (i); |
1816 | if (gimple_code (stmt) == GIMPLE_ASM) | |
cb8e078d | 1817 | return NULL_TREE; |
726a989a | 1818 | if (gimple_code (stmt) != GIMPLE_CALL) |
cb8e078d JJ |
1819 | continue; |
1820 | ||
726a989a | 1821 | callee = gimple_call_fndecl (stmt); |
12f9ddbc RG |
1822 | if (!callee |
1823 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
1824 | /* All regular builtins are ok, just obviously not alloca. */ | |
1825 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA) | |
cb8e078d JJ |
1826 | return NULL_TREE; |
1827 | ||
1828 | if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
ff9d1adc | 1829 | goto second_stack_restore; |
cb8e078d JJ |
1830 | } |
1831 | ||
ff9d1adc | 1832 | if (!gsi_end_p (i)) |
cb8e078d JJ |
1833 | return NULL_TREE; |
1834 | ||
ff9d1adc RH |
1835 | /* Allow one successor of the exit block, or zero successors. */ |
1836 | switch (EDGE_COUNT (bb->succs)) | |
1837 | { | |
1838 | case 0: | |
1839 | break; | |
1840 | case 1: | |
1841 | if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR) | |
1842 | return NULL_TREE; | |
1843 | break; | |
1844 | default: | |
1845 | return NULL_TREE; | |
1846 | } | |
1847 | second_stack_restore: | |
cb8e078d | 1848 | |
ff9d1adc RH |
1849 | /* If there's exactly one use, then zap the call to __builtin_stack_save. |
1850 | If there are multiple uses, then the last one should remove the call. | |
1851 | In any case, whether the call to __builtin_stack_save can be removed | |
1852 | or not is irrelevant to removing the call to __builtin_stack_restore. */ | |
1853 | if (has_single_use (gimple_call_arg (call, 0))) | |
1854 | { | |
1855 | gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
1856 | if (is_gimple_call (stack_save)) | |
1857 | { | |
1858 | callee = gimple_call_fndecl (stack_save); | |
1859 | if (callee | |
1860 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
1861 | && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) | |
1862 | { | |
1863 | gimple_stmt_iterator stack_save_gsi; | |
1864 | tree rhs; | |
cb8e078d | 1865 | |
ff9d1adc RH |
1866 | stack_save_gsi = gsi_for_stmt (stack_save); |
1867 | rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
1868 | update_call_from_tree (&stack_save_gsi, rhs); | |
1869 | } | |
1870 | } | |
1871 | } | |
cb8e078d | 1872 | |
726a989a | 1873 | /* No effect, so the statement will be deleted. */ |
cb8e078d JJ |
1874 | return integer_zero_node; |
1875 | } | |
726a989a | 1876 | |
d7bd8aeb JJ |
1877 | /* If va_list type is a simple pointer and nothing special is needed, |
1878 | optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
1879 | __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
1880 | pointer assignment. */ | |
1881 | ||
1882 | static tree | |
726a989a | 1883 | optimize_stdarg_builtin (gimple call) |
d7bd8aeb | 1884 | { |
35cbb299 | 1885 | tree callee, lhs, rhs, cfun_va_list; |
d7bd8aeb | 1886 | bool va_list_simple_ptr; |
db3927fb | 1887 | location_t loc = gimple_location (call); |
d7bd8aeb | 1888 | |
726a989a | 1889 | if (gimple_code (call) != GIMPLE_CALL) |
d7bd8aeb JJ |
1890 | return NULL_TREE; |
1891 | ||
726a989a | 1892 | callee = gimple_call_fndecl (call); |
35cbb299 KT |
1893 | |
1894 | cfun_va_list = targetm.fn_abi_va_list (callee); | |
1895 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
1896 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
1897 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
1898 | ||
d7bd8aeb JJ |
1899 | switch (DECL_FUNCTION_CODE (callee)) |
1900 | { | |
1901 | case BUILT_IN_VA_START: | |
1902 | if (!va_list_simple_ptr | |
1903 | || targetm.expand_builtin_va_start != NULL | |
726a989a | 1904 | || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) |
d7bd8aeb JJ |
1905 | return NULL_TREE; |
1906 | ||
726a989a | 1907 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
1908 | return NULL_TREE; |
1909 | ||
726a989a | 1910 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
1911 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
1912 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 1913 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb | 1914 | return NULL_TREE; |
b8698a0f | 1915 | |
db3927fb AH |
1916 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
1917 | rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG], | |
726a989a | 1918 | 1, integer_zero_node); |
db3927fb | 1919 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
1920 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
1921 | ||
1922 | case BUILT_IN_VA_COPY: | |
1923 | if (!va_list_simple_ptr) | |
1924 | return NULL_TREE; | |
1925 | ||
726a989a | 1926 | if (gimple_call_num_args (call) != 2) |
d7bd8aeb JJ |
1927 | return NULL_TREE; |
1928 | ||
726a989a | 1929 | lhs = gimple_call_arg (call, 0); |
d7bd8aeb JJ |
1930 | if (!POINTER_TYPE_P (TREE_TYPE (lhs)) |
1931 | || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
35cbb299 | 1932 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
1933 | return NULL_TREE; |
1934 | ||
db3927fb | 1935 | lhs = build_fold_indirect_ref_loc (loc, lhs); |
726a989a | 1936 | rhs = gimple_call_arg (call, 1); |
d7bd8aeb | 1937 | if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) |
35cbb299 | 1938 | != TYPE_MAIN_VARIANT (cfun_va_list)) |
d7bd8aeb JJ |
1939 | return NULL_TREE; |
1940 | ||
db3927fb | 1941 | rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); |
d7bd8aeb JJ |
1942 | return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); |
1943 | ||
1944 | case BUILT_IN_VA_END: | |
726a989a | 1945 | /* No effect, so the statement will be deleted. */ |
d7bd8aeb JJ |
1946 | return integer_zero_node; |
1947 | ||
1948 | default: | |
1949 | gcc_unreachable (); | |
1950 | } | |
1951 | } | |
726a989a | 1952 | |
6de9cd9a DN |
1953 | /* A simple pass that attempts to fold all builtin functions. This pass |
1954 | is run after we've propagated as many constants as we can. */ | |
1955 | ||
c2924966 | 1956 | static unsigned int |
6de9cd9a DN |
1957 | execute_fold_all_builtins (void) |
1958 | { | |
a7d6ba24 | 1959 | bool cfg_changed = false; |
6de9cd9a | 1960 | basic_block bb; |
7b0e48fb | 1961 | unsigned int todoflags = 0; |
b8698a0f | 1962 | |
6de9cd9a DN |
1963 | FOR_EACH_BB (bb) |
1964 | { | |
726a989a RB |
1965 | gimple_stmt_iterator i; |
1966 | for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
6de9cd9a | 1967 | { |
726a989a | 1968 | gimple stmt, old_stmt; |
6de9cd9a | 1969 | tree callee, result; |
10a0d495 | 1970 | enum built_in_function fcode; |
6de9cd9a | 1971 | |
726a989a RB |
1972 | stmt = gsi_stmt (i); |
1973 | ||
1974 | if (gimple_code (stmt) != GIMPLE_CALL) | |
10a0d495 | 1975 | { |
726a989a | 1976 | gsi_next (&i); |
10a0d495 JJ |
1977 | continue; |
1978 | } | |
726a989a | 1979 | callee = gimple_call_fndecl (stmt); |
6de9cd9a | 1980 | if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) |
10a0d495 | 1981 | { |
726a989a | 1982 | gsi_next (&i); |
10a0d495 JJ |
1983 | continue; |
1984 | } | |
1985 | fcode = DECL_FUNCTION_CODE (callee); | |
6de9cd9a | 1986 | |
cbdd87d4 | 1987 | result = gimple_fold_builtin (stmt); |
53a8f709 UB |
1988 | |
1989 | if (result) | |
726a989a | 1990 | gimple_remove_stmt_histograms (cfun, stmt); |
53a8f709 | 1991 | |
6de9cd9a DN |
1992 | if (!result) |
1993 | switch (DECL_FUNCTION_CODE (callee)) | |
1994 | { | |
1995 | case BUILT_IN_CONSTANT_P: | |
1996 | /* Resolve __builtin_constant_p. If it hasn't been | |
1997 | folded to integer_one_node by now, it's fairly | |
1998 | certain that the value simply isn't constant. */ | |
726a989a | 1999 | result = integer_zero_node; |
6de9cd9a DN |
2000 | break; |
2001 | ||
cb8e078d | 2002 | case BUILT_IN_STACK_RESTORE: |
726a989a | 2003 | result = optimize_stack_restore (i); |
d7bd8aeb JJ |
2004 | if (result) |
2005 | break; | |
726a989a | 2006 | gsi_next (&i); |
d7bd8aeb JJ |
2007 | continue; |
2008 | ||
2009 | case BUILT_IN_VA_START: | |
2010 | case BUILT_IN_VA_END: | |
2011 | case BUILT_IN_VA_COPY: | |
2012 | /* These shouldn't be folded before pass_stdarg. */ | |
726a989a | 2013 | result = optimize_stdarg_builtin (stmt); |
cb8e078d JJ |
2014 | if (result) |
2015 | break; | |
2016 | /* FALLTHRU */ | |
2017 | ||
6de9cd9a | 2018 | default: |
726a989a | 2019 | gsi_next (&i); |
6de9cd9a DN |
2020 | continue; |
2021 | } | |
2022 | ||
2023 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2024 | { | |
2025 | fprintf (dump_file, "Simplified\n "); | |
726a989a | 2026 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2027 | } |
2028 | ||
726a989a | 2029 | old_stmt = stmt; |
726a989a | 2030 | if (!update_call_from_tree (&i, result)) |
4bad83f5 RG |
2031 | { |
2032 | gimplify_and_update_call_from_tree (&i, result); | |
2033 | todoflags |= TODO_update_address_taken; | |
2034 | } | |
cfaab3a9 | 2035 | |
726a989a | 2036 | stmt = gsi_stmt (i); |
cff4e50d | 2037 | update_stmt (stmt); |
cfaab3a9 | 2038 | |
726a989a RB |
2039 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) |
2040 | && gimple_purge_dead_eh_edges (bb)) | |
a7d6ba24 | 2041 | cfg_changed = true; |
6de9cd9a DN |
2042 | |
2043 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2044 | { | |
2045 | fprintf (dump_file, "to\n "); | |
726a989a | 2046 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
6de9cd9a DN |
2047 | fprintf (dump_file, "\n"); |
2048 | } | |
10a0d495 JJ |
2049 | |
2050 | /* Retry the same statement if it changed into another | |
2051 | builtin, there might be new opportunities now. */ | |
726a989a | 2052 | if (gimple_code (stmt) != GIMPLE_CALL) |
10a0d495 | 2053 | { |
726a989a | 2054 | gsi_next (&i); |
10a0d495 JJ |
2055 | continue; |
2056 | } | |
726a989a | 2057 | callee = gimple_call_fndecl (stmt); |
10a0d495 | 2058 | if (!callee |
726a989a | 2059 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL |
10a0d495 | 2060 | || DECL_FUNCTION_CODE (callee) == fcode) |
726a989a | 2061 | gsi_next (&i); |
6de9cd9a DN |
2062 | } |
2063 | } | |
b8698a0f | 2064 | |
a7d6ba24 | 2065 | /* Delete unreachable blocks. */ |
7b0e48fb DB |
2066 | if (cfg_changed) |
2067 | todoflags |= TODO_cleanup_cfg; | |
b8698a0f | 2068 | |
7b0e48fb | 2069 | return todoflags; |
6de9cd9a DN |
2070 | } |
2071 | ||
750628d8 | 2072 | |
b8698a0f | 2073 | struct gimple_opt_pass pass_fold_builtins = |
6de9cd9a | 2074 | { |
8ddbbcae JH |
2075 | { |
2076 | GIMPLE_PASS, | |
6de9cd9a DN |
2077 | "fab", /* name */ |
2078 | NULL, /* gate */ | |
2079 | execute_fold_all_builtins, /* execute */ | |
2080 | NULL, /* sub */ | |
2081 | NULL, /* next */ | |
2082 | 0, /* static_pass_number */ | |
7072a650 | 2083 | TV_NONE, /* tv_id */ |
7faade0f | 2084 | PROP_cfg | PROP_ssa, /* properties_required */ |
6de9cd9a DN |
2085 | 0, /* properties_provided */ |
2086 | 0, /* properties_destroyed */ | |
2087 | 0, /* todo_flags_start */ | |
b28b1600 JJ |
2088 | TODO_dump_func |
2089 | | TODO_verify_ssa | |
8ddbbcae JH |
2090 | | TODO_update_ssa /* todo_flags_finish */ |
2091 | } | |
6de9cd9a | 2092 | }; |