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e6a23add | 1 | /* Conditional Dead Call Elimination pass for the GNU compiler. |
fbd26352 | 2 | Copyright (C) 2008-2019 Free Software Foundation, Inc. |
e6a23add | 3 | Contributed by Xinliang David Li <davidxl@google.com> |
4 | ||
5 | This file is part of GCC. | |
48e1416a | 6 | |
e6a23add | 7 | GCC is free software; you can redistribute it and/or modify it |
8 | under the terms of the GNU General Public License as published by the | |
9 | Free Software Foundation; either version 3, or (at your option) any | |
10 | later version. | |
48e1416a | 11 | |
e6a23add | 12 | GCC is distributed in the hope that it will be useful, but WITHOUT |
13 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
48e1416a | 16 | |
e6a23add | 17 | You should have received a copy of the GNU General Public License |
18 | along with GCC; see the file COPYING3. If not see | |
19 | <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
9ef16211 | 24 | #include "backend.h" |
25 | #include "tree.h" | |
26 | #include "gimple.h" | |
7c29e30e | 27 | #include "cfghooks.h" |
28 | #include "tree-pass.h" | |
9ef16211 | 29 | #include "ssa.h" |
7c29e30e | 30 | #include "gimple-pretty-print.h" |
b20a8bb4 | 31 | #include "fold-const.h" |
9ed99284 | 32 | #include "stor-layout.h" |
dcf1a1ec | 33 | #include "gimple-iterator.h" |
073c1fd5 | 34 | #include "tree-cfg.h" |
073c1fd5 | 35 | #include "tree-into-ssa.h" |
ed9eac2c | 36 | #include "builtins.h" |
37 | #include "internal-fn.h" | |
8ba6639c | 38 | #include "tree-dfa.h" |
e6a23add | 39 | \f |
40 | ||
ed9eac2c | 41 | /* This pass serves two closely-related purposes: |
e6a23add | 42 | |
ed9eac2c | 43 | 1. It conditionally executes calls that set errno if (a) the result of |
44 | the call is unused and (b) a simple range check on the arguments can | |
45 | detect most cases where errno does not need to be set. | |
e6a23add | 46 | |
ed9eac2c | 47 | This is the "conditional dead-code elimination" that gave the pass |
48 | its original name, since the call is dead for most argument values. | |
49 | The calls for which it helps are usually part of the C++ abstraction | |
50 | penalty exposed after inlining. | |
51 | ||
52 | 2. It looks for calls to built-in functions that set errno and whose | |
53 | result is used. It checks whether there is an associated internal | |
54 | function that doesn't set errno and whether the target supports | |
55 | that internal function. If so, the pass uses the internal function | |
56 | to compute the result of the built-in function but still arranges | |
57 | for errno to be set when necessary. There are two ways of setting | |
58 | errno: | |
59 | ||
60 | a. by protecting the original call with the same argument checks as (1) | |
61 | ||
62 | b. by protecting the original call with a check that the result | |
63 | of the internal function is not equal to itself (i.e. is NaN). | |
64 | ||
65 | (b) requires that NaNs are the only erroneous results. It is not | |
66 | appropriate for functions like log, which returns ERANGE for zero | |
67 | arguments. (b) is also likely to perform worse than (a) because it | |
68 | requires the result to be calculated first. The pass therefore uses | |
69 | (a) when it can and uses (b) as a fallback. | |
70 | ||
71 | For (b) the pass can replace the original call with a call to | |
72 | IFN_SET_EDOM, if the target supports direct assignments to errno. | |
73 | ||
74 | In both cases, arguments that require errno to be set should occur | |
75 | rarely in practice. Checks of the errno result should also be rare, | |
76 | but the compiler would need powerful interprocedural analysis to | |
77 | prove that errno is not checked. It's much easier to add argument | |
78 | checks or result checks instead. | |
79 | ||
80 | An example of (1) is: | |
e6a23add | 81 | |
07816e94 | 82 | log (x); // Mostly dead call |
e6a23add | 83 | ==> |
07816e94 | 84 | if (__builtin_islessequal (x, 0)) |
85 | log (x); | |
86 | ||
e6a23add | 87 | With this change, call to log (x) is effectively eliminated, as |
ed9eac2c | 88 | in the majority of the cases, log won't be called with x out of |
e6a23add | 89 | range. The branch is totally predictable, so the branch cost |
48e1416a | 90 | is low. |
e6a23add | 91 | |
ed9eac2c | 92 | An example of (2) is: |
93 | ||
94 | y = sqrt (x); | |
95 | ==> | |
ed9eac2c | 96 | if (__builtin_isless (x, 0)) |
bfcba496 | 97 | y = sqrt (x); |
98 | else | |
99 | y = IFN_SQRT (x); | |
ed9eac2c | 100 | In the vast majority of cases we should then never need to call sqrt. |
101 | ||
e6a23add | 102 | Note that library functions are not supposed to clear errno to zero without |
103 | error. See IEEE Std 1003.1, section 2.3 Error Numbers, and section 7.5:3 of | |
104 | ISO/IEC 9899 (C99). | |
105 | ||
106 | The condition wrapping the builtin call is conservatively set to avoid too | |
ed9eac2c | 107 | aggressive (wrong) shrink wrapping. */ |
e6a23add | 108 | |
109 | ||
48e1416a | 110 | /* A structure for representing input domain of |
e6a23add | 111 | a function argument in integer. If the lower |
48e1416a | 112 | bound is -inf, has_lb is set to false. If the |
113 | upper bound is +inf, has_ub is false. | |
114 | is_lb_inclusive and is_ub_inclusive are flags | |
115 | to indicate if lb and ub value are inclusive | |
e6a23add | 116 | respectively. */ |
117 | ||
6dc50383 | 118 | struct inp_domain |
e6a23add | 119 | { |
120 | int lb; | |
121 | int ub; | |
122 | bool has_lb; | |
123 | bool has_ub; | |
124 | bool is_lb_inclusive; | |
125 | bool is_ub_inclusive; | |
6dc50383 | 126 | }; |
e6a23add | 127 | |
e6a23add | 128 | /* A helper function to construct and return an input |
48e1416a | 129 | domain object. LB is the lower bound, HAS_LB is |
e6a23add | 130 | a boolean flag indicating if the lower bound exists, |
131 | and LB_INCLUSIVE is a boolean flag indicating if the | |
132 | lower bound is inclusive or not. UB, HAS_UB, and | |
48e1416a | 133 | UB_INCLUSIVE have the same meaning, but for upper |
e6a23add | 134 | bound of the domain. */ |
135 | ||
136 | static inp_domain | |
137 | get_domain (int lb, bool has_lb, bool lb_inclusive, | |
138 | int ub, bool has_ub, bool ub_inclusive) | |
139 | { | |
140 | inp_domain domain; | |
141 | domain.lb = lb; | |
142 | domain.has_lb = has_lb; | |
143 | domain.is_lb_inclusive = lb_inclusive; | |
144 | domain.ub = ub; | |
145 | domain.has_ub = has_ub; | |
146 | domain.is_ub_inclusive = ub_inclusive; | |
147 | return domain; | |
148 | } | |
149 | ||
48e1416a | 150 | /* A helper function to check the target format for the |
e6a23add | 151 | argument type. In this implementation, only IEEE formats |
48e1416a | 152 | are supported. ARG is the call argument to be checked. |
e6a23add | 153 | Returns true if the format is supported. To support other |
154 | target formats, function get_no_error_domain needs to be | |
48e1416a | 155 | enhanced to have range bounds properly computed. Since |
156 | the check is cheap (very small number of candidates | |
e6a23add | 157 | to be checked), the result is not cached for each float type. */ |
158 | ||
159 | static bool | |
160 | check_target_format (tree arg) | |
161 | { | |
162 | tree type; | |
3754d046 | 163 | machine_mode mode; |
e6a23add | 164 | const struct real_format *rfmt; |
48e1416a | 165 | |
e6a23add | 166 | type = TREE_TYPE (arg); |
167 | mode = TYPE_MODE (type); | |
168 | rfmt = REAL_MODE_FORMAT (mode); | |
defc07a6 | 169 | if ((mode == SFmode |
b161ca01 | 170 | && (rfmt == &ieee_single_format || rfmt == &mips_single_format |
171 | || rfmt == &motorola_single_format)) | |
defc07a6 | 172 | || (mode == DFmode |
b161ca01 | 173 | && (rfmt == &ieee_double_format || rfmt == &mips_double_format |
174 | || rfmt == &motorola_double_format)) | |
f4d3c071 | 175 | /* For long double, we cannot really check XFmode |
48e1416a | 176 | which is only defined on intel platforms. |
177 | Candidate pre-selection using builtin function | |
178 | code guarantees that we are checking formats | |
e6a23add | 179 | for long double modes: double, quad, and extended. */ |
48e1416a | 180 | || (mode != SFmode && mode != DFmode |
e6a23add | 181 | && (rfmt == &ieee_quad_format |
defc07a6 | 182 | || rfmt == &mips_quad_format |
b161ca01 | 183 | || rfmt == &ieee_extended_motorola_format |
48e1416a | 184 | || rfmt == &ieee_extended_intel_96_format |
185 | || rfmt == &ieee_extended_intel_128_format | |
e6a23add | 186 | || rfmt == &ieee_extended_intel_96_round_53_format))) |
187 | return true; | |
188 | ||
189 | return false; | |
190 | } | |
191 | ||
192 | \f | |
193 | /* A helper function to help select calls to pow that are suitable for | |
194 | conditional DCE transformation. It looks for pow calls that can be | |
195 | guided with simple conditions. Such calls either have constant base | |
48e1416a | 196 | values or base values converted from integers. Returns true if |
e6a23add | 197 | the pow call POW_CALL is a candidate. */ |
198 | ||
199 | /* The maximum integer bit size for base argument of a pow call | |
200 | that is suitable for shrink-wrapping transformation. */ | |
201 | #define MAX_BASE_INT_BIT_SIZE 32 | |
202 | ||
203 | static bool | |
1a91d914 | 204 | check_pow (gcall *pow_call) |
e6a23add | 205 | { |
206 | tree base, expn; | |
207 | enum tree_code bc, ec; | |
208 | ||
75a70cf9 | 209 | if (gimple_call_num_args (pow_call) != 2) |
e6a23add | 210 | return false; |
211 | ||
75a70cf9 | 212 | base = gimple_call_arg (pow_call, 0); |
213 | expn = gimple_call_arg (pow_call, 1); | |
e6a23add | 214 | |
215 | if (!check_target_format (expn)) | |
216 | return false; | |
217 | ||
218 | bc = TREE_CODE (base); | |
219 | ec = TREE_CODE (expn); | |
220 | ||
221 | /* Folding candidates are not interesting. | |
222 | Can actually assert that it is already folded. */ | |
223 | if (ec == REAL_CST && bc == REAL_CST) | |
224 | return false; | |
225 | ||
226 | if (bc == REAL_CST) | |
227 | { | |
228 | /* Only handle a fixed range of constant. */ | |
229 | REAL_VALUE_TYPE mv; | |
230 | REAL_VALUE_TYPE bcv = TREE_REAL_CST (base); | |
20cb53c9 | 231 | if (real_equal (&bcv, &dconst1)) |
e6a23add | 232 | return false; |
1b67971e | 233 | if (real_less (&bcv, &dconst1)) |
e6a23add | 234 | return false; |
e913b5cd | 235 | real_from_integer (&mv, TYPE_MODE (TREE_TYPE (base)), 256, UNSIGNED); |
1b67971e | 236 | if (real_less (&mv, &bcv)) |
e6a23add | 237 | return false; |
238 | return true; | |
239 | } | |
240 | else if (bc == SSA_NAME) | |
241 | { | |
7ecda5e8 | 242 | tree base_val0, type; |
42acab1c | 243 | gimple *base_def; |
e6a23add | 244 | int bit_sz; |
245 | ||
246 | /* Only handles cases where base value is converted | |
48e1416a | 247 | from integer values. */ |
e6a23add | 248 | base_def = SSA_NAME_DEF_STMT (base); |
75a70cf9 | 249 | if (gimple_code (base_def) != GIMPLE_ASSIGN) |
e6a23add | 250 | return false; |
251 | ||
75a70cf9 | 252 | if (gimple_assign_rhs_code (base_def) != FLOAT_EXPR) |
e6a23add | 253 | return false; |
75a70cf9 | 254 | base_val0 = gimple_assign_rhs1 (base_def); |
e6a23add | 255 | |
7ecda5e8 | 256 | type = TREE_TYPE (base_val0); |
e6a23add | 257 | if (TREE_CODE (type) != INTEGER_TYPE) |
258 | return false; | |
259 | bit_sz = TYPE_PRECISION (type); | |
260 | /* If the type of the base is too wide, | |
261 | the resulting shrink wrapping condition | |
262 | will be too conservative. */ | |
263 | if (bit_sz > MAX_BASE_INT_BIT_SIZE) | |
264 | return false; | |
265 | ||
266 | return true; | |
267 | } | |
268 | else | |
269 | return false; | |
270 | } | |
271 | ||
272 | /* A helper function to help select candidate function calls that are | |
273 | suitable for conditional DCE. Candidate functions must have single | |
274 | valid input domain in this implementation except for pow (see check_pow). | |
275 | Returns true if the function call is a candidate. */ | |
276 | ||
277 | static bool | |
1a91d914 | 278 | check_builtin_call (gcall *bcall) |
e6a23add | 279 | { |
280 | tree arg; | |
281 | ||
75a70cf9 | 282 | arg = gimple_call_arg (bcall, 0); |
e6a23add | 283 | return check_target_format (arg); |
284 | } | |
285 | ||
ed9eac2c | 286 | /* Return true if built-in function call CALL calls a math function |
287 | and if we know how to test the range of its arguments to detect _most_ | |
288 | situations in which errno is not set. The test must err on the side | |
289 | of treating non-erroneous values as potentially erroneous. */ | |
e6a23add | 290 | |
291 | static bool | |
ed9eac2c | 292 | can_test_argument_range (gcall *call) |
e6a23add | 293 | { |
ed9eac2c | 294 | switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call))) |
e6a23add | 295 | { |
296 | /* Trig functions. */ | |
297 | CASE_FLT_FN (BUILT_IN_ACOS): | |
298 | CASE_FLT_FN (BUILT_IN_ASIN): | |
299 | /* Hyperbolic functions. */ | |
300 | CASE_FLT_FN (BUILT_IN_ACOSH): | |
301 | CASE_FLT_FN (BUILT_IN_ATANH): | |
302 | CASE_FLT_FN (BUILT_IN_COSH): | |
303 | CASE_FLT_FN (BUILT_IN_SINH): | |
304 | /* Log functions. */ | |
305 | CASE_FLT_FN (BUILT_IN_LOG): | |
306 | CASE_FLT_FN (BUILT_IN_LOG2): | |
307 | CASE_FLT_FN (BUILT_IN_LOG10): | |
308 | CASE_FLT_FN (BUILT_IN_LOG1P): | |
309 | /* Exp functions. */ | |
310 | CASE_FLT_FN (BUILT_IN_EXP): | |
311 | CASE_FLT_FN (BUILT_IN_EXP2): | |
312 | CASE_FLT_FN (BUILT_IN_EXP10): | |
313 | CASE_FLT_FN (BUILT_IN_EXPM1): | |
314 | CASE_FLT_FN (BUILT_IN_POW10): | |
315 | /* Sqrt. */ | |
316 | CASE_FLT_FN (BUILT_IN_SQRT): | |
8c32188e | 317 | CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT): |
e6a23add | 318 | return check_builtin_call (call); |
319 | /* Special one: two argument pow. */ | |
320 | case BUILT_IN_POW: | |
321 | return check_pow (call); | |
322 | default: | |
323 | break; | |
324 | } | |
325 | ||
326 | return false; | |
327 | } | |
328 | ||
ed9eac2c | 329 | /* Return true if CALL can produce a domain error (EDOM) but can never |
330 | produce a pole, range overflow or range underflow error (all ERANGE). | |
331 | This means that we can tell whether a function would have set errno | |
332 | by testing whether the result is a NaN. */ | |
333 | ||
334 | static bool | |
335 | edom_only_function (gcall *call) | |
336 | { | |
337 | switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call))) | |
338 | { | |
339 | CASE_FLT_FN (BUILT_IN_ACOS): | |
340 | CASE_FLT_FN (BUILT_IN_ASIN): | |
341 | CASE_FLT_FN (BUILT_IN_ATAN): | |
342 | CASE_FLT_FN (BUILT_IN_COS): | |
343 | CASE_FLT_FN (BUILT_IN_SIGNIFICAND): | |
344 | CASE_FLT_FN (BUILT_IN_SIN): | |
345 | CASE_FLT_FN (BUILT_IN_SQRT): | |
8c32188e | 346 | CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT): |
ed9eac2c | 347 | CASE_FLT_FN (BUILT_IN_FMOD): |
348 | CASE_FLT_FN (BUILT_IN_REMAINDER): | |
349 | return true; | |
350 | ||
351 | default: | |
352 | return false; | |
353 | } | |
354 | } | |
8ba6639c | 355 | |
356 | /* Return true if it is structurally possible to guard CALL. */ | |
357 | ||
358 | static bool | |
359 | can_guard_call_p (gimple *call) | |
360 | { | |
361 | return (!stmt_ends_bb_p (call) | |
362 | || find_fallthru_edge (gimple_bb (call)->succs)); | |
363 | } | |
e6a23add | 364 | \f |
225a6e0d | 365 | /* For a comparison code return the comparison code we should use if we don't |
366 | HONOR_NANS. */ | |
367 | ||
368 | static enum tree_code | |
369 | comparison_code_if_no_nans (tree_code code) | |
370 | { | |
371 | switch (code) | |
372 | { | |
373 | case UNLT_EXPR: | |
374 | return LT_EXPR; | |
375 | case UNGT_EXPR: | |
376 | return GT_EXPR; | |
377 | case UNLE_EXPR: | |
378 | return LE_EXPR; | |
379 | case UNGE_EXPR: | |
380 | return GE_EXPR; | |
381 | case UNEQ_EXPR: | |
382 | return EQ_EXPR; | |
383 | case LTGT_EXPR: | |
384 | return NE_EXPR; | |
385 | ||
386 | case LT_EXPR: | |
387 | case GT_EXPR: | |
388 | case LE_EXPR: | |
389 | case GE_EXPR: | |
390 | case EQ_EXPR: | |
391 | case NE_EXPR: | |
392 | return code; | |
393 | ||
394 | default: | |
395 | gcc_unreachable (); | |
396 | } | |
397 | } | |
398 | ||
07816e94 | 399 | /* A helper function to generate gimple statements for one bound |
400 | comparison, so that the built-in function is called whenever | |
401 | TCODE <ARG, LBUB> is *false*. TEMP_NAME1/TEMP_NAME2 are names | |
402 | of the temporaries, CONDS is a vector holding the produced GIMPLE | |
403 | statements, and NCONDS points to the variable holding the number of | |
404 | logical comparisons. CONDS is either empty or a list ended with a | |
405 | null tree. */ | |
e6a23add | 406 | |
407 | static void | |
48e1416a | 408 | gen_one_condition (tree arg, int lbub, |
e6a23add | 409 | enum tree_code tcode, |
410 | const char *temp_name1, | |
75a70cf9 | 411 | const char *temp_name2, |
42acab1c | 412 | vec<gimple *> conds, |
e6a23add | 413 | unsigned *nconds) |
414 | { | |
225a6e0d | 415 | if (!HONOR_NANS (arg)) |
416 | tcode = comparison_code_if_no_nans (tcode); | |
417 | ||
e6a23add | 418 | tree lbub_real_cst, lbub_cst, float_type; |
419 | tree temp, tempn, tempc, tempcn; | |
1a91d914 | 420 | gassign *stmt1; |
421 | gassign *stmt2; | |
422 | gcond *stmt3; | |
e6a23add | 423 | |
424 | float_type = TREE_TYPE (arg); | |
425 | lbub_cst = build_int_cst (integer_type_node, lbub); | |
426 | lbub_real_cst = build_real_from_int_cst (float_type, lbub_cst); | |
427 | ||
428 | temp = create_tmp_var (float_type, temp_name1); | |
75a70cf9 | 429 | stmt1 = gimple_build_assign (temp, arg); |
e6a23add | 430 | tempn = make_ssa_name (temp, stmt1); |
75a70cf9 | 431 | gimple_assign_set_lhs (stmt1, tempn); |
e6a23add | 432 | |
433 | tempc = create_tmp_var (boolean_type_node, temp_name2); | |
75a70cf9 | 434 | stmt2 = gimple_build_assign (tempc, |
435 | fold_build2 (tcode, | |
436 | boolean_type_node, | |
437 | tempn, lbub_real_cst)); | |
e6a23add | 438 | tempcn = make_ssa_name (tempc, stmt2); |
75a70cf9 | 439 | gimple_assign_set_lhs (stmt2, tempcn); |
440 | ||
441 | stmt3 = gimple_build_cond_from_tree (tempcn, NULL_TREE, NULL_TREE); | |
f1f41a6c | 442 | conds.quick_push (stmt1); |
443 | conds.quick_push (stmt2); | |
444 | conds.quick_push (stmt3); | |
e6a23add | 445 | (*nconds)++; |
446 | } | |
447 | ||
448 | /* A helper function to generate GIMPLE statements for | |
449 | out of input domain check. ARG is the call argument | |
450 | to be runtime checked, DOMAIN holds the valid domain | |
451 | for the given function, CONDS points to the vector | |
48e1416a | 452 | holding the result GIMPLE statements. *NCONDS is |
453 | the number of logical comparisons. This function | |
e6a23add | 454 | produces no more than two logical comparisons, one |
455 | for lower bound check, one for upper bound check. */ | |
456 | ||
457 | static void | |
458 | gen_conditions_for_domain (tree arg, inp_domain domain, | |
42acab1c | 459 | vec<gimple *> conds, |
e6a23add | 460 | unsigned *nconds) |
461 | { | |
462 | if (domain.has_lb) | |
463 | gen_one_condition (arg, domain.lb, | |
464 | (domain.is_lb_inclusive | |
07816e94 | 465 | ? UNGE_EXPR : UNGT_EXPR), |
e6a23add | 466 | "DCE_COND_LB", "DCE_COND_LB_TEST", |
467 | conds, nconds); | |
468 | ||
469 | if (domain.has_ub) | |
470 | { | |
471 | /* Now push a separator. */ | |
472 | if (domain.has_lb) | |
f1f41a6c | 473 | conds.quick_push (NULL); |
e6a23add | 474 | |
475 | gen_one_condition (arg, domain.ub, | |
476 | (domain.is_ub_inclusive | |
07816e94 | 477 | ? UNLE_EXPR : UNLT_EXPR), |
e6a23add | 478 | "DCE_COND_UB", "DCE_COND_UB_TEST", |
479 | conds, nconds); | |
480 | } | |
481 | } | |
482 | ||
483 | ||
484 | /* A helper function to generate condition | |
485 | code for the y argument in call pow (some_const, y). | |
48e1416a | 486 | See candidate selection in check_pow. Since the |
e6a23add | 487 | candidates' base values have a limited range, |
488 | the guarded code generated for y are simple: | |
07816e94 | 489 | if (__builtin_isgreater (y, max_y)) |
e6a23add | 490 | pow (const, y); |
491 | Note max_y can be computed separately for each | |
492 | const base, but in this implementation, we | |
493 | choose to compute it using the max base | |
494 | in the allowed range for the purpose of | |
495 | simplicity. BASE is the constant base value, | |
496 | EXPN is the expression for the exponent argument, | |
497 | *CONDS is the vector to hold resulting statements, | |
498 | and *NCONDS is the number of logical conditions. */ | |
499 | ||
500 | static void | |
501 | gen_conditions_for_pow_cst_base (tree base, tree expn, | |
42acab1c | 502 | vec<gimple *> conds, |
e6a23add | 503 | unsigned *nconds) |
504 | { | |
48e1416a | 505 | inp_domain exp_domain; |
506 | /* Validate the range of the base constant to make | |
e6a23add | 507 | sure it is consistent with check_pow. */ |
508 | REAL_VALUE_TYPE mv; | |
509 | REAL_VALUE_TYPE bcv = TREE_REAL_CST (base); | |
20cb53c9 | 510 | gcc_assert (!real_equal (&bcv, &dconst1) |
1b67971e | 511 | && !real_less (&bcv, &dconst1)); |
e913b5cd | 512 | real_from_integer (&mv, TYPE_MODE (TREE_TYPE (base)), 256, UNSIGNED); |
1b67971e | 513 | gcc_assert (!real_less (&mv, &bcv)); |
e6a23add | 514 | |
515 | exp_domain = get_domain (0, false, false, | |
516 | 127, true, false); | |
517 | ||
518 | gen_conditions_for_domain (expn, exp_domain, | |
519 | conds, nconds); | |
520 | } | |
521 | ||
522 | /* Generate error condition code for pow calls with | |
523 | non constant base values. The candidates selected | |
524 | have their base argument value converted from | |
525 | integer (see check_pow) value (1, 2, 4 bytes), and | |
526 | the max exp value is computed based on the size | |
527 | of the integer type (i.e. max possible base value). | |
528 | The resulting input domain for exp argument is thus | |
48e1416a | 529 | conservative (smaller than the max value allowed by |
530 | the runtime value of the base). BASE is the integer | |
531 | base value, EXPN is the expression for the exponent | |
532 | argument, *CONDS is the vector to hold resulting | |
533 | statements, and *NCONDS is the number of logical | |
e6a23add | 534 | conditions. */ |
535 | ||
536 | static void | |
537 | gen_conditions_for_pow_int_base (tree base, tree expn, | |
42acab1c | 538 | vec<gimple *> conds, |
e6a23add | 539 | unsigned *nconds) |
540 | { | |
42acab1c | 541 | gimple *base_def; |
f018d957 | 542 | tree base_val0; |
7ecda5e8 | 543 | tree int_type; |
e6a23add | 544 | tree temp, tempn; |
75a70cf9 | 545 | tree cst0; |
42acab1c | 546 | gimple *stmt1, *stmt2; |
e6a23add | 547 | int bit_sz, max_exp; |
548 | inp_domain exp_domain; | |
549 | ||
550 | base_def = SSA_NAME_DEF_STMT (base); | |
75a70cf9 | 551 | base_val0 = gimple_assign_rhs1 (base_def); |
7ecda5e8 | 552 | int_type = TREE_TYPE (base_val0); |
e6a23add | 553 | bit_sz = TYPE_PRECISION (int_type); |
48e1416a | 554 | gcc_assert (bit_sz > 0 |
e6a23add | 555 | && bit_sz <= MAX_BASE_INT_BIT_SIZE); |
556 | ||
557 | /* Determine the max exp argument value according to | |
558 | the size of the base integer. The max exp value | |
559 | is conservatively estimated assuming IEEE754 double | |
560 | precision format. */ | |
561 | if (bit_sz == 8) | |
562 | max_exp = 128; | |
563 | else if (bit_sz == 16) | |
564 | max_exp = 64; | |
565 | else | |
f018d957 | 566 | { |
567 | gcc_assert (bit_sz == MAX_BASE_INT_BIT_SIZE); | |
568 | max_exp = 32; | |
569 | } | |
e6a23add | 570 | |
571 | /* For pow ((double)x, y), generate the following conditions: | |
572 | cond 1: | |
573 | temp1 = x; | |
07816e94 | 574 | if (__builtin_islessequal (temp1, 0)) |
e6a23add | 575 | |
576 | cond 2: | |
577 | temp2 = y; | |
07816e94 | 578 | if (__builtin_isgreater (temp2, max_exp_real_cst)) */ |
e6a23add | 579 | |
580 | /* Generate condition in reverse order -- first | |
581 | the condition for the exp argument. */ | |
582 | ||
583 | exp_domain = get_domain (0, false, false, | |
584 | max_exp, true, true); | |
585 | ||
586 | gen_conditions_for_domain (expn, exp_domain, | |
587 | conds, nconds); | |
588 | ||
589 | /* Now generate condition for the base argument. | |
590 | Note it does not use the helper function | |
591 | gen_conditions_for_domain because the base | |
592 | type is integer. */ | |
593 | ||
594 | /* Push a separator. */ | |
f1f41a6c | 595 | conds.quick_push (NULL); |
e6a23add | 596 | |
597 | temp = create_tmp_var (int_type, "DCE_COND1"); | |
598 | cst0 = build_int_cst (int_type, 0); | |
75a70cf9 | 599 | stmt1 = gimple_build_assign (temp, base_val0); |
e6a23add | 600 | tempn = make_ssa_name (temp, stmt1); |
75a70cf9 | 601 | gimple_assign_set_lhs (stmt1, tempn); |
07816e94 | 602 | stmt2 = gimple_build_cond (GT_EXPR, tempn, cst0, NULL_TREE, NULL_TREE); |
e6a23add | 603 | |
f1f41a6c | 604 | conds.quick_push (stmt1); |
605 | conds.quick_push (stmt2); | |
e6a23add | 606 | (*nconds)++; |
607 | } | |
608 | ||
609 | /* Method to generate conditional statements for guarding conditionally | |
610 | dead calls to pow. One or more statements can be generated for | |
611 | each logical condition. Statement groups of different conditions | |
f1f41a6c | 612 | are separated by a NULL tree and they are stored in the vec |
e6a23add | 613 | conds. The number of logical conditions are stored in *nconds. |
614 | ||
615 | See C99 standard, 7.12.7.4:2, for description of pow (x, y). | |
616 | The precise condition for domain errors are complex. In this | |
617 | implementation, a simplified (but conservative) valid domain | |
618 | for x and y are used: x is positive to avoid dom errors, while | |
619 | y is smaller than a upper bound (depending on x) to avoid range | |
620 | errors. Runtime code is generated to check x (if not constant) | |
621 | and y against the valid domain. If it is out, jump to the call, | |
622 | otherwise the call is bypassed. POW_CALL is the call statement, | |
623 | *CONDS is a vector holding the resulting condition statements, | |
624 | and *NCONDS is the number of logical conditions. */ | |
625 | ||
626 | static void | |
42acab1c | 627 | gen_conditions_for_pow (gcall *pow_call, vec<gimple *> conds, |
e6a23add | 628 | unsigned *nconds) |
629 | { | |
630 | tree base, expn; | |
f018d957 | 631 | enum tree_code bc; |
e6a23add | 632 | |
1b4345f7 | 633 | gcc_checking_assert (check_pow (pow_call)); |
e6a23add | 634 | |
635 | *nconds = 0; | |
636 | ||
75a70cf9 | 637 | base = gimple_call_arg (pow_call, 0); |
638 | expn = gimple_call_arg (pow_call, 1); | |
e6a23add | 639 | |
640 | bc = TREE_CODE (base); | |
e6a23add | 641 | |
642 | if (bc == REAL_CST) | |
f018d957 | 643 | gen_conditions_for_pow_cst_base (base, expn, conds, nconds); |
e6a23add | 644 | else if (bc == SSA_NAME) |
f018d957 | 645 | gen_conditions_for_pow_int_base (base, expn, conds, nconds); |
e6a23add | 646 | else |
647 | gcc_unreachable (); | |
648 | } | |
649 | ||
650 | /* A helper routine to help computing the valid input domain | |
651 | for a builtin function. See C99 7.12.7 for details. In this | |
652 | implementation, we only handle single region domain. The | |
653 | resulting region can be conservative (smaller) than the actual | |
654 | one and rounded to integers. Some of the bounds are documented | |
655 | in the standard, while other limit constants are computed | |
48e1416a | 656 | assuming IEEE floating point format (for SF and DF modes). |
657 | Since IEEE only sets minimum requirements for long double format, | |
658 | different long double formats exist under different implementations | |
659 | (e.g, 64 bit double precision (DF), 80 bit double-extended | |
660 | precision (XF), and 128 bit quad precision (QF) ). For simplicity, | |
661 | in this implementation, the computed bounds for long double assume | |
662 | 64 bit format (DF), and are therefore conservative. Another | |
e6a23add | 663 | assumption is that single precision float type is always SF mode, |
48e1416a | 664 | and double type is DF mode. This function is quite |
e6a23add | 665 | implementation specific, so it may not be suitable to be part of |
666 | builtins.c. This needs to be revisited later to see if it can | |
667 | be leveraged in x87 assembly expansion. */ | |
668 | ||
669 | static inp_domain | |
670 | get_no_error_domain (enum built_in_function fnc) | |
671 | { | |
672 | switch (fnc) | |
673 | { | |
674 | /* Trig functions: return [-1, +1] */ | |
675 | CASE_FLT_FN (BUILT_IN_ACOS): | |
676 | CASE_FLT_FN (BUILT_IN_ASIN): | |
677 | return get_domain (-1, true, true, | |
678 | 1, true, true); | |
679 | /* Hyperbolic functions. */ | |
680 | CASE_FLT_FN (BUILT_IN_ACOSH): | |
681 | /* acosh: [1, +inf) */ | |
682 | return get_domain (1, true, true, | |
683 | 1, false, false); | |
684 | CASE_FLT_FN (BUILT_IN_ATANH): | |
685 | /* atanh: (-1, +1) */ | |
686 | return get_domain (-1, true, false, | |
687 | 1, true, false); | |
688 | case BUILT_IN_COSHF: | |
689 | case BUILT_IN_SINHF: | |
690 | /* coshf: (-89, +89) */ | |
691 | return get_domain (-89, true, false, | |
692 | 89, true, false); | |
693 | case BUILT_IN_COSH: | |
694 | case BUILT_IN_SINH: | |
695 | case BUILT_IN_COSHL: | |
696 | case BUILT_IN_SINHL: | |
697 | /* cosh: (-710, +710) */ | |
698 | return get_domain (-710, true, false, | |
699 | 710, true, false); | |
700 | /* Log functions: (0, +inf) */ | |
701 | CASE_FLT_FN (BUILT_IN_LOG): | |
702 | CASE_FLT_FN (BUILT_IN_LOG2): | |
703 | CASE_FLT_FN (BUILT_IN_LOG10): | |
704 | return get_domain (0, true, false, | |
705 | 0, false, false); | |
706 | CASE_FLT_FN (BUILT_IN_LOG1P): | |
707 | return get_domain (-1, true, false, | |
708 | 0, false, false); | |
709 | /* Exp functions. */ | |
710 | case BUILT_IN_EXPF: | |
711 | case BUILT_IN_EXPM1F: | |
712 | /* expf: (-inf, 88) */ | |
713 | return get_domain (-1, false, false, | |
714 | 88, true, false); | |
715 | case BUILT_IN_EXP: | |
716 | case BUILT_IN_EXPM1: | |
717 | case BUILT_IN_EXPL: | |
718 | case BUILT_IN_EXPM1L: | |
719 | /* exp: (-inf, 709) */ | |
720 | return get_domain (-1, false, false, | |
721 | 709, true, false); | |
722 | case BUILT_IN_EXP2F: | |
723 | /* exp2f: (-inf, 128) */ | |
724 | return get_domain (-1, false, false, | |
725 | 128, true, false); | |
726 | case BUILT_IN_EXP2: | |
727 | case BUILT_IN_EXP2L: | |
728 | /* exp2: (-inf, 1024) */ | |
729 | return get_domain (-1, false, false, | |
730 | 1024, true, false); | |
731 | case BUILT_IN_EXP10F: | |
732 | case BUILT_IN_POW10F: | |
733 | /* exp10f: (-inf, 38) */ | |
734 | return get_domain (-1, false, false, | |
735 | 38, true, false); | |
736 | case BUILT_IN_EXP10: | |
737 | case BUILT_IN_POW10: | |
738 | case BUILT_IN_EXP10L: | |
739 | case BUILT_IN_POW10L: | |
740 | /* exp10: (-inf, 308) */ | |
741 | return get_domain (-1, false, false, | |
742 | 308, true, false); | |
743 | /* sqrt: [0, +inf) */ | |
744 | CASE_FLT_FN (BUILT_IN_SQRT): | |
8c32188e | 745 | CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT): |
e6a23add | 746 | return get_domain (0, true, true, |
747 | 0, false, false); | |
748 | default: | |
48e1416a | 749 | gcc_unreachable (); |
e6a23add | 750 | } |
751 | ||
48e1416a | 752 | gcc_unreachable (); |
e6a23add | 753 | } |
754 | ||
755 | /* The function to generate shrink wrap conditions for a partially | |
756 | dead builtin call whose return value is not used anywhere, | |
757 | but has to be kept live due to potential error condition. | |
48e1416a | 758 | BI_CALL is the builtin call, CONDS is the vector of statements |
759 | for condition code, NCODES is the pointer to the number of | |
e6a23add | 760 | logical conditions. Statements belonging to different logical |
761 | condition are separated by NULL tree in the vector. */ | |
762 | ||
763 | static void | |
42acab1c | 764 | gen_shrink_wrap_conditions (gcall *bi_call, vec<gimple *> conds, |
e6a23add | 765 | unsigned int *nconds) |
766 | { | |
1a91d914 | 767 | gcall *call; |
75a70cf9 | 768 | tree fn; |
e6a23add | 769 | enum built_in_function fnc; |
770 | ||
f1f41a6c | 771 | gcc_assert (nconds && conds.exists ()); |
772 | gcc_assert (conds.length () == 0); | |
75a70cf9 | 773 | gcc_assert (is_gimple_call (bi_call)); |
e6a23add | 774 | |
775 | call = bi_call; | |
75a70cf9 | 776 | fn = gimple_call_fndecl (call); |
a0e9bfbb | 777 | gcc_assert (fn && fndecl_built_in_p (fn)); |
e6a23add | 778 | fnc = DECL_FUNCTION_CODE (fn); |
779 | *nconds = 0; | |
780 | ||
781 | if (fnc == BUILT_IN_POW) | |
782 | gen_conditions_for_pow (call, conds, nconds); | |
783 | else | |
784 | { | |
785 | tree arg; | |
786 | inp_domain domain = get_no_error_domain (fnc); | |
787 | *nconds = 0; | |
75a70cf9 | 788 | arg = gimple_call_arg (bi_call, 0); |
e6a23add | 789 | gen_conditions_for_domain (arg, domain, conds, nconds); |
790 | } | |
791 | ||
792 | return; | |
793 | } | |
794 | ||
ed9eac2c | 795 | /* Shrink-wrap BI_CALL so that it is only called when one of the NCONDS |
bfcba496 | 796 | conditions in CONDS is false. Also move BI_NEWCALL to a new basic block |
797 | when it is non-null, it is called while all of the CONDS are true. */ | |
ed9eac2c | 798 | |
8ba6639c | 799 | static void |
ed9eac2c | 800 | shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds, |
bfcba496 | 801 | unsigned int nconds, |
802 | gcall *bi_newcall = NULL) | |
e6a23add | 803 | { |
75a70cf9 | 804 | gimple_stmt_iterator bi_call_bsi; |
bfcba496 | 805 | basic_block bi_call_bb, bi_newcall_bb, join_tgt_bb, guard_bb; |
e6a23add | 806 | edge join_tgt_in_edge_from_call, join_tgt_in_edge_fall_thru; |
807 | edge bi_call_in_edge0, guard_bb_in_edge; | |
ed9eac2c | 808 | unsigned tn_cond_stmts; |
e6a23add | 809 | unsigned ci; |
42acab1c | 810 | gimple *cond_expr = NULL; |
811 | gimple *cond_expr_start; | |
e6a23add | 812 | |
aee1460a | 813 | /* The cfg we want to create looks like this: |
bfcba496 | 814 | [guard n-1] <- guard_bb (old block) |
815 | | \ | |
816 | | [guard n-2] } | |
817 | | / \ } | |
818 | | / ... } new blocks | |
819 | | / [guard 0] } | |
820 | | / / | } | |
821 | [call] | <- bi_call_bb } | |
822 | \ [newcall] <-bi_newcall_bb} | |
823 | \ | | |
824 | [join] <- join_tgt_bb (old iff call must end bb) | |
aee1460a | 825 | possible EH edges (only if [join] is old) |
826 | ||
827 | When [join] is new, the immediate dominators for these blocks are: | |
828 | ||
829 | 1. [guard n-1]: unchanged | |
830 | 2. [call]: [guard n-1] | |
bfcba496 | 831 | 3. [newcall]: [guard 0] |
832 | 4. [guard m]: [guard m+1] for 0 <= m <= n-2 | |
833 | 5. [join]: [guard n-1] | |
aee1460a | 834 | |
835 | We punt for the more complex case case of [join] being old and | |
836 | simply free the dominance info. We also punt on postdominators, | |
837 | which aren't expected to be available at this point anyway. */ | |
75a70cf9 | 838 | bi_call_bb = gimple_bb (bi_call); |
e6a23add | 839 | |
36ee0f30 | 840 | /* Now find the join target bb -- split bi_call_bb if needed. */ |
841 | if (stmt_ends_bb_p (bi_call)) | |
842 | { | |
8ba6639c | 843 | /* We checked that there was a fallthrough edge in |
844 | can_guard_call_p. */ | |
36ee0f30 | 845 | join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs); |
8ba6639c | 846 | gcc_assert (join_tgt_in_edge_from_call); |
095c7123 | 847 | /* We don't want to handle PHIs. */ |
848 | if (EDGE_COUNT (join_tgt_in_edge_from_call->dest->preds) > 1) | |
849 | join_tgt_bb = split_edge (join_tgt_in_edge_from_call); | |
850 | else | |
b6e43945 | 851 | { |
852 | join_tgt_bb = join_tgt_in_edge_from_call->dest; | |
853 | /* We may have degenerate PHIs in the destination. Propagate | |
854 | those out. */ | |
855 | for (gphi_iterator i = gsi_start_phis (join_tgt_bb); !gsi_end_p (i);) | |
856 | { | |
857 | gphi *phi = i.phi (); | |
858 | replace_uses_by (gimple_phi_result (phi), | |
859 | gimple_phi_arg_def (phi, 0)); | |
860 | remove_phi_node (&i, true); | |
861 | } | |
862 | } | |
36ee0f30 | 863 | } |
864 | else | |
095c7123 | 865 | { |
866 | join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call); | |
867 | join_tgt_bb = join_tgt_in_edge_from_call->dest; | |
868 | } | |
e6a23add | 869 | |
75a70cf9 | 870 | bi_call_bsi = gsi_for_stmt (bi_call); |
e6a23add | 871 | |
e6a23add | 872 | /* Now it is time to insert the first conditional expression |
873 | into bi_call_bb and split this bb so that bi_call is | |
874 | shrink-wrapped. */ | |
f1f41a6c | 875 | tn_cond_stmts = conds.length (); |
e6a23add | 876 | cond_expr = NULL; |
f1f41a6c | 877 | cond_expr_start = conds[0]; |
e6a23add | 878 | for (ci = 0; ci < tn_cond_stmts; ci++) |
879 | { | |
42acab1c | 880 | gimple *c = conds[ci]; |
e6a23add | 881 | gcc_assert (c || ci != 0); |
882 | if (!c) | |
883 | break; | |
75a70cf9 | 884 | gsi_insert_before (&bi_call_bsi, c, GSI_SAME_STMT); |
e6a23add | 885 | cond_expr = c; |
886 | } | |
e6a23add | 887 | ci++; |
75a70cf9 | 888 | gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND); |
e6a23add | 889 | |
e01adea7 | 890 | typedef std::pair<edge, edge> edge_pair; |
891 | auto_vec<edge_pair, 8> edges; | |
892 | ||
e6a23add | 893 | bi_call_in_edge0 = split_block (bi_call_bb, cond_expr); |
894 | bi_call_in_edge0->flags &= ~EDGE_FALLTHRU; | |
07816e94 | 895 | bi_call_in_edge0->flags |= EDGE_FALSE_VALUE; |
b7635218 | 896 | guard_bb = bi_call_bb; |
e6a23add | 897 | bi_call_bb = bi_call_in_edge0->dest; |
b7635218 | 898 | join_tgt_in_edge_fall_thru = make_edge (guard_bb, join_tgt_bb, |
07816e94 | 899 | EDGE_TRUE_VALUE); |
e6a23add | 900 | |
e01adea7 | 901 | edges.reserve (nconds); |
902 | edges.quick_push (edge_pair (bi_call_in_edge0, join_tgt_in_edge_fall_thru)); | |
e6a23add | 903 | |
904 | /* Code generation for the rest of the conditions */ | |
e01adea7 | 905 | for (unsigned int i = 1; i < nconds; ++i) |
e6a23add | 906 | { |
907 | unsigned ci0; | |
908 | edge bi_call_in_edge; | |
75a70cf9 | 909 | gimple_stmt_iterator guard_bsi = gsi_for_stmt (cond_expr_start); |
e6a23add | 910 | ci0 = ci; |
f1f41a6c | 911 | cond_expr_start = conds[ci0]; |
e6a23add | 912 | for (; ci < tn_cond_stmts; ci++) |
913 | { | |
42acab1c | 914 | gimple *c = conds[ci]; |
e6a23add | 915 | gcc_assert (c || ci != ci0); |
916 | if (!c) | |
917 | break; | |
75a70cf9 | 918 | gsi_insert_before (&guard_bsi, c, GSI_SAME_STMT); |
e6a23add | 919 | cond_expr = c; |
920 | } | |
e6a23add | 921 | ci++; |
75a70cf9 | 922 | gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND); |
e6a23add | 923 | guard_bb_in_edge = split_block (guard_bb, cond_expr); |
924 | guard_bb_in_edge->flags &= ~EDGE_FALLTHRU; | |
07816e94 | 925 | guard_bb_in_edge->flags |= EDGE_TRUE_VALUE; |
e6a23add | 926 | |
07816e94 | 927 | bi_call_in_edge = make_edge (guard_bb, bi_call_bb, EDGE_FALSE_VALUE); |
e01adea7 | 928 | edges.quick_push (edge_pair (bi_call_in_edge, guard_bb_in_edge)); |
929 | } | |
930 | ||
bfcba496 | 931 | /* Move BI_NEWCALL to new basic block when it is non-null. */ |
932 | if (bi_newcall) | |
933 | { | |
934 | /* Get bi_newcall_bb by split join_tgt_in_edge_fall_thru edge, | |
935 | and move BI_NEWCALL to bi_newcall_bb. */ | |
936 | bi_newcall_bb = split_edge (join_tgt_in_edge_fall_thru); | |
937 | gimple_stmt_iterator to_gsi = gsi_start_bb (bi_newcall_bb); | |
938 | gimple_stmt_iterator from_gsi = gsi_for_stmt (bi_newcall); | |
939 | gsi_move_before (&from_gsi, &to_gsi); | |
940 | join_tgt_in_edge_fall_thru = EDGE_SUCC (bi_newcall_bb, 0); | |
941 | join_tgt_bb = join_tgt_in_edge_fall_thru->dest; | |
942 | ||
943 | tree bi_newcall_lhs = gimple_call_lhs (bi_newcall); | |
944 | tree bi_call_lhs = gimple_call_lhs (bi_call); | |
945 | if (!bi_call_lhs) | |
946 | { | |
947 | bi_call_lhs = copy_ssa_name (bi_newcall_lhs); | |
948 | gimple_call_set_lhs (bi_call, bi_call_lhs); | |
949 | SSA_NAME_DEF_STMT (bi_call_lhs) = bi_call; | |
950 | } | |
951 | ||
952 | /* Create phi node for lhs of BI_CALL and BI_NEWCALL. */ | |
953 | gphi *new_phi = create_phi_node (copy_ssa_name (bi_newcall_lhs), | |
954 | join_tgt_bb); | |
955 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (new_phi)) | |
956 | = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (bi_newcall_lhs); | |
957 | add_phi_arg (new_phi, bi_call_lhs, join_tgt_in_edge_from_call, | |
958 | gimple_location (bi_call)); | |
959 | add_phi_arg (new_phi, bi_newcall_lhs, join_tgt_in_edge_fall_thru, | |
960 | gimple_location (bi_newcall)); | |
961 | ||
962 | /* Replace all use of original return value with result of phi node. */ | |
963 | use_operand_p use_p; | |
964 | gimple *use_stmt; | |
965 | imm_use_iterator iterator; | |
966 | FOR_EACH_IMM_USE_STMT (use_stmt, iterator, bi_newcall_lhs) | |
967 | if (use_stmt != new_phi) | |
968 | FOR_EACH_IMM_USE_ON_STMT (use_p, iterator) | |
969 | SET_USE (use_p, PHI_RESULT (new_phi)); | |
970 | } | |
971 | ||
e01adea7 | 972 | /* Now update the probability and profile information, processing the |
973 | guards in order of execution. | |
974 | ||
975 | There are two approaches we could take here. On the one hand we | |
976 | could assign a probability of X to the call block and distribute | |
977 | that probability among its incoming edges. On the other hand we | |
978 | could assign a probability of X to each individual call edge. | |
979 | ||
980 | The choice only affects calls that have more than one condition. | |
981 | In those cases, the second approach would give the call block | |
982 | a greater probability than the first. However, the difference | |
983 | is only small, and our chosen X is a pure guess anyway. | |
984 | ||
985 | Here we take the second approach because it's slightly simpler | |
986 | and because it's easy to see that it doesn't lose profile counts. */ | |
db9cef39 | 987 | bi_call_bb->count = profile_count::zero (); |
e01adea7 | 988 | while (!edges.is_empty ()) |
989 | { | |
990 | edge_pair e = edges.pop (); | |
991 | edge call_edge = e.first; | |
992 | edge nocall_edge = e.second; | |
993 | basic_block src_bb = call_edge->src; | |
994 | gcc_assert (src_bb == nocall_edge->src); | |
995 | ||
720cfc43 | 996 | call_edge->probability = profile_probability::very_unlikely (); |
720cfc43 | 997 | nocall_edge->probability = profile_probability::always () |
998 | - call_edge->probability; | |
e01adea7 | 999 | |
ea5d3981 | 1000 | bi_call_bb->count += call_edge->count (); |
e01adea7 | 1001 | |
1002 | if (nocall_edge->dest != join_tgt_bb) | |
205ce1aa | 1003 | nocall_edge->dest->count = src_bb->count - bi_call_bb->count; |
e6a23add | 1004 | } |
1005 | ||
aee1460a | 1006 | if (dom_info_available_p (CDI_DOMINATORS)) |
1007 | { | |
1008 | /* The split_blocks leave [guard 0] as the immediate dominator | |
1009 | of [call] and [call] as the immediate dominator of [join]. | |
1010 | Fix them up. */ | |
1011 | set_immediate_dominator (CDI_DOMINATORS, bi_call_bb, guard_bb); | |
1012 | set_immediate_dominator (CDI_DOMINATORS, join_tgt_bb, guard_bb); | |
1013 | } | |
1014 | ||
e6a23add | 1015 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1016 | { | |
1017 | location_t loc; | |
75a70cf9 | 1018 | loc = gimple_location (bi_call); |
e6a23add | 1019 | fprintf (dump_file, |
1020 | "%s:%d: note: function call is shrink-wrapped" | |
1021 | " into error conditions.\n", | |
1022 | LOCATION_FILE (loc), LOCATION_LINE (loc)); | |
1023 | } | |
e6a23add | 1024 | } |
1025 | ||
ed9eac2c | 1026 | /* Shrink-wrap BI_CALL so that it is only called when it might set errno |
8ba6639c | 1027 | (but is always called if it would set errno). */ |
ed9eac2c | 1028 | |
8ba6639c | 1029 | static void |
ed9eac2c | 1030 | shrink_wrap_one_built_in_call (gcall *bi_call) |
1031 | { | |
1032 | unsigned nconds = 0; | |
1033 | auto_vec<gimple *, 12> conds; | |
1034 | gen_shrink_wrap_conditions (bi_call, conds, &nconds); | |
8ba6639c | 1035 | gcc_assert (nconds != 0); |
1036 | shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds); | |
ed9eac2c | 1037 | } |
1038 | ||
1039 | /* Return true if built-in function call CALL could be implemented using | |
1040 | a combination of an internal function to compute the result and a | |
1041 | separate call to set errno. */ | |
1042 | ||
1043 | static bool | |
1044 | can_use_internal_fn (gcall *call) | |
1045 | { | |
1046 | /* Only replace calls that set errno. */ | |
1047 | if (!gimple_vdef (call)) | |
1048 | return false; | |
1049 | ||
ed9eac2c | 1050 | /* See whether there is an internal function for this built-in. */ |
1051 | if (replacement_internal_fn (call) == IFN_LAST) | |
1052 | return false; | |
1053 | ||
1054 | /* See whether we can catch all cases where errno would be set, | |
1055 | while still avoiding the call in most cases. */ | |
1056 | if (!can_test_argument_range (call) | |
1057 | && !edom_only_function (call)) | |
1058 | return false; | |
1059 | ||
1060 | return true; | |
1061 | } | |
1062 | ||
8ba6639c | 1063 | /* Implement built-in function call CALL using an internal function. */ |
ed9eac2c | 1064 | |
8ba6639c | 1065 | static void |
ed9eac2c | 1066 | use_internal_fn (gcall *call) |
1067 | { | |
8ba6639c | 1068 | /* We'll be inserting another call with the same arguments after the |
1069 | lhs has been set, so prevent any possible coalescing failure from | |
1070 | having both values live at once. See PR 71020. */ | |
1071 | replace_abnormal_ssa_names (call); | |
1072 | ||
ed9eac2c | 1073 | unsigned nconds = 0; |
1074 | auto_vec<gimple *, 12> conds; | |
bfcba496 | 1075 | bool is_arg_conds = false; |
28af9b9c | 1076 | if (can_test_argument_range (call)) |
8ba6639c | 1077 | { |
1078 | gen_shrink_wrap_conditions (call, conds, &nconds); | |
bfcba496 | 1079 | is_arg_conds = true; |
8ba6639c | 1080 | gcc_assert (nconds != 0); |
1081 | } | |
1082 | else | |
1083 | gcc_assert (edom_only_function (call)); | |
ed9eac2c | 1084 | |
1085 | internal_fn ifn = replacement_internal_fn (call); | |
1086 | gcc_assert (ifn != IFN_LAST); | |
1087 | ||
1088 | /* Construct the new call, with the same arguments as the original one. */ | |
1089 | auto_vec <tree, 16> args; | |
1090 | unsigned int nargs = gimple_call_num_args (call); | |
1091 | for (unsigned int i = 0; i < nargs; ++i) | |
1092 | args.safe_push (gimple_call_arg (call, i)); | |
1093 | gcall *new_call = gimple_build_call_internal_vec (ifn, args); | |
1094 | gimple_set_location (new_call, gimple_location (call)); | |
989f02dc | 1095 | gimple_call_set_nothrow (new_call, gimple_call_nothrow_p (call)); |
ed9eac2c | 1096 | |
1097 | /* Transfer the LHS to the new call. */ | |
1098 | tree lhs = gimple_call_lhs (call); | |
1099 | gimple_call_set_lhs (new_call, lhs); | |
1100 | gimple_call_set_lhs (call, NULL_TREE); | |
1101 | SSA_NAME_DEF_STMT (lhs) = new_call; | |
1102 | ||
1103 | /* Insert the new call. */ | |
1104 | gimple_stmt_iterator gsi = gsi_for_stmt (call); | |
1105 | gsi_insert_before (&gsi, new_call, GSI_SAME_STMT); | |
1106 | ||
1107 | if (nconds == 0) | |
1108 | { | |
1109 | /* Skip the call if LHS == LHS. If we reach here, EDOM is the only | |
1110 | valid errno value and it is used iff the result is NaN. */ | |
1111 | conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs, | |
1112 | NULL_TREE, NULL_TREE)); | |
1113 | nconds++; | |
1114 | ||
1115 | /* Try replacing the original call with a direct assignment to | |
1116 | errno, via an internal function. */ | |
1117 | if (set_edom_supported_p () && !stmt_ends_bb_p (call)) | |
1118 | { | |
1119 | gimple_stmt_iterator gsi = gsi_for_stmt (call); | |
1120 | gcall *new_call = gimple_build_call_internal (IFN_SET_EDOM, 0); | |
1263a9e1 | 1121 | gimple_move_vops (new_call, call); |
ed9eac2c | 1122 | gimple_set_location (new_call, gimple_location (call)); |
1123 | gsi_replace (&gsi, new_call, false); | |
1124 | call = new_call; | |
1125 | } | |
1126 | } | |
bfcba496 | 1127 | shrink_wrap_one_built_in_call_with_conds (call, conds, nconds, |
1128 | is_arg_conds ? new_call : NULL); | |
ed9eac2c | 1129 | } |
1130 | ||
e6a23add | 1131 | /* The top level function for conditional dead code shrink |
1132 | wrapping transformation. */ | |
1133 | ||
8ba6639c | 1134 | static void |
1a91d914 | 1135 | shrink_wrap_conditional_dead_built_in_calls (vec<gcall *> calls) |
e6a23add | 1136 | { |
e6a23add | 1137 | unsigned i = 0; |
1138 | ||
f1f41a6c | 1139 | unsigned n = calls.length (); |
e6a23add | 1140 | for (; i < n ; i++) |
1141 | { | |
1a91d914 | 1142 | gcall *bi_call = calls[i]; |
ed9eac2c | 1143 | if (gimple_call_lhs (bi_call)) |
8ba6639c | 1144 | use_internal_fn (bi_call); |
ed9eac2c | 1145 | else |
8ba6639c | 1146 | shrink_wrap_one_built_in_call (bi_call); |
e6a23add | 1147 | } |
e6a23add | 1148 | } |
1149 | ||
65b0537f | 1150 | namespace { |
1151 | ||
1152 | const pass_data pass_data_call_cdce = | |
1153 | { | |
1154 | GIMPLE_PASS, /* type */ | |
1155 | "cdce", /* name */ | |
1156 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 1157 | TV_TREE_CALL_CDCE, /* tv_id */ |
1158 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1159 | 0, /* properties_provided */ | |
1160 | 0, /* properties_destroyed */ | |
1161 | 0, /* todo_flags_start */ | |
8b88439e | 1162 | 0, /* todo_flags_finish */ |
65b0537f | 1163 | }; |
e6a23add | 1164 | |
65b0537f | 1165 | class pass_call_cdce : public gimple_opt_pass |
1166 | { | |
1167 | public: | |
1168 | pass_call_cdce (gcc::context *ctxt) | |
1169 | : gimple_opt_pass (pass_data_call_cdce, ctxt) | |
1170 | {} | |
1171 | ||
1172 | /* opt_pass methods: */ | |
ed9eac2c | 1173 | virtual bool gate (function *) |
65b0537f | 1174 | { |
1175 | /* The limit constants used in the implementation | |
1176 | assume IEEE floating point format. Other formats | |
1177 | can be supported in the future if needed. */ | |
ed9eac2c | 1178 | return flag_tree_builtin_call_dce != 0; |
65b0537f | 1179 | } |
e6a23add | 1180 | |
65b0537f | 1181 | virtual unsigned int execute (function *); |
1182 | ||
1183 | }; // class pass_call_cdce | |
1184 | ||
1185 | unsigned int | |
1186 | pass_call_cdce::execute (function *fun) | |
e6a23add | 1187 | { |
1188 | basic_block bb; | |
75a70cf9 | 1189 | gimple_stmt_iterator i; |
1a91d914 | 1190 | auto_vec<gcall *> cond_dead_built_in_calls; |
65b0537f | 1191 | FOR_EACH_BB_FN (bb, fun) |
e6a23add | 1192 | { |
ed9eac2c | 1193 | /* Skip blocks that are being optimized for size, since our |
1194 | transformation always increases code size. */ | |
1195 | if (optimize_bb_for_size_p (bb)) | |
1196 | continue; | |
1197 | ||
e6a23add | 1198 | /* Collect dead call candidates. */ |
75a70cf9 | 1199 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
e6a23add | 1200 | { |
1a91d914 | 1201 | gcall *stmt = dyn_cast <gcall *> (gsi_stmt (i)); |
ed9eac2c | 1202 | if (stmt |
1203 | && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL) | |
1204 | && (gimple_call_lhs (stmt) | |
1205 | ? can_use_internal_fn (stmt) | |
8ba6639c | 1206 | : can_test_argument_range (stmt)) |
1207 | && can_guard_call_p (stmt)) | |
e6a23add | 1208 | { |
1209 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1210 | { | |
1211 | fprintf (dump_file, "Found conditional dead call: "); | |
75a70cf9 | 1212 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
e6a23add | 1213 | fprintf (dump_file, "\n"); |
1214 | } | |
f1f41a6c | 1215 | if (!cond_dead_built_in_calls.exists ()) |
1216 | cond_dead_built_in_calls.create (64); | |
1217 | cond_dead_built_in_calls.safe_push (stmt); | |
e6a23add | 1218 | } |
1219 | } | |
1220 | } | |
1221 | ||
f1f41a6c | 1222 | if (!cond_dead_built_in_calls.exists ()) |
86ed2c77 | 1223 | return 0; |
1224 | ||
8ba6639c | 1225 | shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls); |
1226 | free_dominance_info (CDI_POST_DOMINATORS); | |
1227 | /* As we introduced new control-flow we need to insert PHI-nodes | |
1228 | for the call-clobbers of the remaining call. */ | |
1229 | mark_virtual_operands_for_renaming (fun); | |
1230 | return TODO_update_ssa; | |
e6a23add | 1231 | } |
1232 | ||
cbe8bda8 | 1233 | } // anon namespace |
1234 | ||
1235 | gimple_opt_pass * | |
1236 | make_pass_call_cdce (gcc::context *ctxt) | |
1237 | { | |
1238 | return new pass_call_cdce (ctxt); | |
1239 | } |