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1 : : /* Conditional Dead Call Elimination pass for the GNU compiler.
2 : : Copyright (C) 2008-2025 Free Software Foundation, Inc.
3 : : Contributed by Xinliang David Li <davidxl@google.com>
4 : :
5 : : This file is part of GCC.
6 : :
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.
11 : :
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.
16 : :
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"
24 : : #include "backend.h"
25 : : #include "tree.h"
26 : : #include "gimple.h"
27 : : #include "cfghooks.h"
28 : : #include "tree-pass.h"
29 : : #include "ssa.h"
30 : : #include "gimple-pretty-print.h"
31 : : #include "fold-const.h"
32 : : #include "stor-layout.h"
33 : : #include "gimple-iterator.h"
34 : : #include "tree-cfg.h"
35 : : #include "tree-into-ssa.h"
36 : : #include "builtins.h"
37 : : #include "internal-fn.h"
38 : : #include "tree-dfa.h"
39 : : #include "tree-eh.h"
40 : :
41 : :
42 : : /* This pass serves two closely-related purposes:
43 : :
44 : : 1. It conditionally executes calls that set errno if (a) the result of
45 : : the call is unused and (b) a simple range check on the arguments can
46 : : detect most cases where errno does not need to be set.
47 : :
48 : : This is the "conditional dead-code elimination" that gave the pass
49 : : its original name, since the call is dead for most argument values.
50 : : The calls for which it helps are usually part of the C++ abstraction
51 : : penalty exposed after inlining.
52 : :
53 : : 2. It looks for calls to built-in functions that set errno and whose
54 : : result is used. It checks whether there is an associated internal
55 : : function that doesn't set errno and whether the target supports
56 : : that internal function. If so, the pass uses the internal function
57 : : to compute the result of the built-in function but still arranges
58 : : for errno to be set when necessary. There are two ways of setting
59 : : errno:
60 : :
61 : : a. by protecting the original call with the same argument checks as (1)
62 : :
63 : : b. by protecting the original call with a check that the result
64 : : of the internal function is not equal to itself (i.e. is NaN).
65 : :
66 : : (b) requires that NaNs are the only erroneous results. It is not
67 : : appropriate for functions like log, which returns ERANGE for zero
68 : : arguments. (b) is also likely to perform worse than (a) because it
69 : : requires the result to be calculated first. The pass therefore uses
70 : : (a) when it can and uses (b) as a fallback.
71 : :
72 : : For (b) the pass can replace the original call with a call to
73 : : IFN_SET_EDOM, if the target supports direct assignments to errno.
74 : :
75 : : In both cases, arguments that require errno to be set should occur
76 : : rarely in practice. Checks of the errno result should also be rare,
77 : : but the compiler would need powerful interprocedural analysis to
78 : : prove that errno is not checked. It's much easier to add argument
79 : : checks or result checks instead.
80 : :
81 : : An example of (1) is:
82 : :
83 : : log (x); // Mostly dead call
84 : : ==>
85 : : if (__builtin_islessequal (x, 0))
86 : : log (x);
87 : :
88 : : With this change, call to log (x) is effectively eliminated, as
89 : : in the majority of the cases, log won't be called with x out of
90 : : range. The branch is totally predictable, so the branch cost
91 : : is low.
92 : :
93 : : An example of (2) is:
94 : :
95 : : y = sqrt (x);
96 : : ==>
97 : : if (__builtin_isless (x, 0))
98 : : y = sqrt (x);
99 : : else
100 : : y = IFN_SQRT (x);
101 : : In the vast majority of cases we should then never need to call sqrt.
102 : :
103 : : Note that library functions are not supposed to clear errno to zero without
104 : : error. See IEEE Std 1003.1, section 2.3 Error Numbers, and section 7.5:3 of
105 : : ISO/IEC 9899 (C99).
106 : :
107 : : The condition wrapping the builtin call is conservatively set to avoid too
108 : : aggressive (wrong) shrink wrapping. */
109 : :
110 : :
111 : : /* A structure for representing input domain of
112 : : a function argument in integer. If the lower
113 : : bound is -inf, has_lb is set to false. If the
114 : : upper bound is +inf, has_ub is false.
115 : : is_lb_inclusive and is_ub_inclusive are flags
116 : : to indicate if lb and ub value are inclusive
117 : : respectively. */
118 : :
119 : : struct inp_domain
120 : : {
121 : : int lb;
122 : : int ub;
123 : : bool has_lb;
124 : : bool has_ub;
125 : : bool is_lb_inclusive;
126 : : bool is_ub_inclusive;
127 : : };
128 : :
129 : : /* A helper function to construct and return an input
130 : : domain object. LB is the lower bound, HAS_LB is
131 : : a boolean flag indicating if the lower bound exists,
132 : : and LB_INCLUSIVE is a boolean flag indicating if the
133 : : lower bound is inclusive or not. UB, HAS_UB, and
134 : : UB_INCLUSIVE have the same meaning, but for upper
135 : : bound of the domain. */
136 : :
137 : : static inp_domain
138 : 2641 : get_domain (int lb, bool has_lb, bool lb_inclusive,
139 : : int ub, bool has_ub, bool ub_inclusive)
140 : : {
141 : 2641 : inp_domain domain;
142 : 2641 : domain.lb = lb;
143 : 2641 : domain.has_lb = has_lb;
144 : 2641 : domain.is_lb_inclusive = lb_inclusive;
145 : 2641 : domain.ub = ub;
146 : 2641 : domain.has_ub = has_ub;
147 : 2641 : domain.is_ub_inclusive = ub_inclusive;
148 : 2641 : return domain;
149 : : }
150 : :
151 : : /* A helper function to check the target format for the
152 : : argument type. In this implementation, only IEEE formats
153 : : are supported. ARG is the call argument to be checked.
154 : : Returns true if the format is supported. To support other
155 : : target formats, function get_no_error_domain needs to be
156 : : enhanced to have range bounds properly computed. Since
157 : : the check is cheap (very small number of candidates
158 : : to be checked), the result is not cached for each float type. */
159 : :
160 : : static bool
161 : 4351 : check_target_format (tree arg)
162 : : {
163 : 4351 : tree type;
164 : 4351 : machine_mode mode;
165 : 4351 : const struct real_format *rfmt;
166 : :
167 : 4351 : type = TREE_TYPE (arg);
168 : 4351 : mode = TYPE_MODE (type);
169 : 4351 : rfmt = REAL_MODE_FORMAT (mode);
170 : 4351 : if ((mode == SFmode
171 : 1331 : && (rfmt == &ieee_single_format || rfmt == &mips_single_format
172 : 0 : || rfmt == &motorola_single_format))
173 : 3020 : || (mode == DFmode
174 : 2086 : && (rfmt == &ieee_double_format || rfmt == &mips_double_format
175 : 0 : || rfmt == &motorola_double_format))
176 : : /* For long double, we cannot really check XFmode
177 : : which is only defined on intel platforms.
178 : : Candidate pre-selection using builtin function
179 : : code guarantees that we are checking formats
180 : : for long double modes: double, quad, and extended. */
181 : 934 : || (mode != SFmode && mode != DFmode
182 : 934 : && (rfmt == &ieee_quad_format
183 : 907 : || rfmt == &mips_quad_format
184 : 907 : || rfmt == &ieee_extended_motorola_format
185 : 907 : || rfmt == &ieee_extended_intel_96_format
186 : 901 : || rfmt == &ieee_extended_intel_128_format
187 : 14 : || rfmt == &ieee_extended_intel_96_round_53_format)))
188 : 4337 : return true;
189 : :
190 : : return false;
191 : : }
192 : :
193 : :
194 : : /* A helper function to help select calls to pow that are suitable for
195 : : conditional DCE transformation. It looks for pow calls that can be
196 : : guided with simple conditions. Such calls either have constant base
197 : : values or base values converted from integers. Returns true if
198 : : the pow call POW_CALL is a candidate. */
199 : :
200 : : /* The maximum integer bit size for base argument of a pow call
201 : : that is suitable for shrink-wrapping transformation. */
202 : : #define MAX_BASE_INT_BIT_SIZE 32
203 : :
204 : : static bool
205 : 52 : check_pow (gcall *pow_call)
206 : : {
207 : 52 : tree base, expn;
208 : 52 : enum tree_code bc, ec;
209 : :
210 : 52 : if (gimple_call_num_args (pow_call) != 2)
211 : : return false;
212 : :
213 : 52 : base = gimple_call_arg (pow_call, 0);
214 : 52 : expn = gimple_call_arg (pow_call, 1);
215 : :
216 : 52 : if (!check_target_format (expn))
217 : : return false;
218 : :
219 : 52 : bc = TREE_CODE (base);
220 : 52 : ec = TREE_CODE (expn);
221 : :
222 : : /* Folding candidates are not interesting.
223 : : Can actually assert that it is already folded. */
224 : 52 : if (ec == REAL_CST && bc == REAL_CST)
225 : : return false;
226 : :
227 : 52 : if (bc == REAL_CST)
228 : : {
229 : : /* Only handle a fixed range of constant. */
230 : 28 : REAL_VALUE_TYPE mv;
231 : 28 : REAL_VALUE_TYPE bcv = TREE_REAL_CST (base);
232 : 28 : if (real_equal (&bcv, &dconst1))
233 : : return false;
234 : 28 : if (real_less (&bcv, &dconst1))
235 : : return false;
236 : 28 : real_from_integer (&mv, TYPE_MODE (TREE_TYPE (base)), 256, UNSIGNED);
237 : 28 : if (real_less (&mv, &bcv))
238 : : return false;
239 : : return true;
240 : : }
241 : 24 : else if (bc == SSA_NAME)
242 : : {
243 : 24 : tree base_val0, type;
244 : 24 : gimple *base_def;
245 : 24 : int bit_sz;
246 : :
247 : : /* Only handles cases where base value is converted
248 : : from integer values. */
249 : 24 : base_def = SSA_NAME_DEF_STMT (base);
250 : 24 : if (gimple_code (base_def) != GIMPLE_ASSIGN)
251 : : return false;
252 : :
253 : 15 : if (gimple_assign_rhs_code (base_def) != FLOAT_EXPR)
254 : : return false;
255 : 15 : base_val0 = gimple_assign_rhs1 (base_def);
256 : :
257 : 15 : type = TREE_TYPE (base_val0);
258 : 15 : if (TREE_CODE (type) != INTEGER_TYPE)
259 : : return false;
260 : 15 : bit_sz = TYPE_PRECISION (type);
261 : : /* If the type of the base is too wide,
262 : : the resulting shrink wrapping condition
263 : : will be too conservative. */
264 : 15 : if (bit_sz != 8 && bit_sz != 16 && bit_sz != MAX_BASE_INT_BIT_SIZE)
265 : : return false;
266 : :
267 : : return true;
268 : : }
269 : : else
270 : : return false;
271 : : }
272 : :
273 : : /* A helper function to help select candidate function calls that are
274 : : suitable for conditional DCE. Candidate functions must have single
275 : : valid input domain in this implementation except for pow (see check_pow).
276 : : Returns true if the function call is a candidate. */
277 : :
278 : : static bool
279 : 4299 : check_builtin_call (gcall *bcall)
280 : : {
281 : 4299 : tree arg;
282 : :
283 : 4299 : arg = gimple_call_arg (bcall, 0);
284 : 4299 : return check_target_format (arg);
285 : : }
286 : :
287 : : /* Return true if built-in function call CALL calls a math function
288 : : and if we know how to test the range of its arguments to detect _most_
289 : : situations in which errno is not set. The test must err on the side
290 : : of treating non-erroneous values as potentially erroneous. */
291 : :
292 : : static bool
293 : 376032 : can_test_argument_range (gcall *call)
294 : : {
295 : 376032 : switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call)))
296 : : {
297 : : /* Trig functions. */
298 : 4299 : CASE_FLT_FN (BUILT_IN_ACOS):
299 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOS):
300 : 4299 : CASE_FLT_FN (BUILT_IN_ACOSPI):
301 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOSPI):
302 : 4299 : CASE_FLT_FN (BUILT_IN_ASIN):
303 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASIN):
304 : 4299 : CASE_FLT_FN (BUILT_IN_ASINPI):
305 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASINPI):
306 : : /* Hyperbolic functions. */
307 : 4299 : CASE_FLT_FN (BUILT_IN_ACOSH):
308 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOSH):
309 : 4299 : CASE_FLT_FN (BUILT_IN_ATANH):
310 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ATANH):
311 : 4299 : CASE_FLT_FN (BUILT_IN_COSH):
312 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_COSH):
313 : 4299 : CASE_FLT_FN (BUILT_IN_SINH):
314 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SINH):
315 : : /* Log functions. */
316 : 4299 : CASE_FLT_FN (BUILT_IN_LOG):
317 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG):
318 : 4299 : CASE_FLT_FN (BUILT_IN_LOG2):
319 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG2):
320 : 4299 : CASE_FLT_FN (BUILT_IN_LOG10):
321 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG10):
322 : 4299 : CASE_FLT_FN (BUILT_IN_LOG1P):
323 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG1P):
324 : : /* Exp functions. */
325 : 4299 : CASE_FLT_FN (BUILT_IN_EXP):
326 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_EXP):
327 : 4299 : CASE_FLT_FN (BUILT_IN_EXP2):
328 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_EXP2):
329 : 4299 : CASE_FLT_FN (BUILT_IN_EXP10):
330 : 4299 : CASE_FLT_FN (BUILT_IN_EXPM1):
331 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_EXPM1):
332 : 4299 : CASE_FLT_FN (BUILT_IN_POW10):
333 : : /* Sqrt. */
334 : 4299 : CASE_FLT_FN (BUILT_IN_SQRT):
335 : 4299 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT):
336 : 4299 : return check_builtin_call (call);
337 : : /* Special one: two argument pow. */
338 : 31 : case BUILT_IN_POW:
339 : 31 : return check_pow (call);
340 : : default:
341 : : break;
342 : : }
343 : :
344 : : return false;
345 : : }
346 : :
347 : : /* Return true if CALL can produce a domain error (EDOM) but can never
348 : : produce a pole, range overflow or range underflow error (all ERANGE).
349 : : This means that we can tell whether a function would have set errno
350 : : by testing whether the result is a NaN. */
351 : :
352 : : static bool
353 : 373 : edom_only_function (gcall *call)
354 : : {
355 : 373 : switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call)))
356 : : {
357 : : CASE_FLT_FN (BUILT_IN_ACOS):
358 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOS):
359 : : CASE_FLT_FN (BUILT_IN_ACOSPI):
360 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOSPI):
361 : : CASE_FLT_FN (BUILT_IN_ASIN):
362 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASIN):
363 : : CASE_FLT_FN (BUILT_IN_ASINPI):
364 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASINPI):
365 : : CASE_FLT_FN (BUILT_IN_COS):
366 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_COS):
367 : : CASE_FLT_FN (BUILT_IN_COSPI):
368 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_COSPI):
369 : : CASE_FLT_FN (BUILT_IN_SIGNIFICAND):
370 : : CASE_FLT_FN (BUILT_IN_SIN):
371 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SIN):
372 : : CASE_FLT_FN (BUILT_IN_SINPI):
373 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SINPI):
374 : : CASE_FLT_FN (BUILT_IN_SQRT):
375 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT):
376 : : CASE_FLT_FN (BUILT_IN_FMOD):
377 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_FMOD):
378 : : CASE_FLT_FN (BUILT_IN_REMAINDER):
379 : : CASE_FLT_FN_FLOATN_NX (BUILT_IN_REMAINDER):
380 : : return true;
381 : :
382 : 95 : default:
383 : 95 : return false;
384 : : }
385 : : }
386 : :
387 : : /* Return true if it is structurally possible to guard CALL. */
388 : :
389 : : static bool
390 : 2780 : can_guard_call_p (gimple *call)
391 : : {
392 : 2780 : return (!stmt_ends_bb_p (call)
393 : 2780 : || find_fallthru_edge (gimple_bb (call)->succs));
394 : : }
395 : :
396 : : /* For a comparison code return the comparison code we should use if we don't
397 : : HONOR_NANS. */
398 : :
399 : : static enum tree_code
400 : 8 : comparison_code_if_no_nans (tree_code code)
401 : : {
402 : 8 : switch (code)
403 : : {
404 : : case UNLT_EXPR:
405 : : return LT_EXPR;
406 : 4 : case UNGT_EXPR:
407 : 4 : return GT_EXPR;
408 : 0 : case UNLE_EXPR:
409 : 0 : return LE_EXPR;
410 : 0 : case UNGE_EXPR:
411 : 0 : return GE_EXPR;
412 : 0 : case UNEQ_EXPR:
413 : 0 : return EQ_EXPR;
414 : 0 : case LTGT_EXPR:
415 : 0 : return NE_EXPR;
416 : :
417 : 0 : case LT_EXPR:
418 : 0 : case GT_EXPR:
419 : 0 : case LE_EXPR:
420 : 0 : case GE_EXPR:
421 : 0 : case EQ_EXPR:
422 : 0 : case NE_EXPR:
423 : 0 : return code;
424 : :
425 : 0 : default:
426 : 0 : gcc_unreachable ();
427 : : }
428 : : }
429 : :
430 : : /* A helper function to generate gimple statements for one bound
431 : : comparison, so that the built-in function is called whenever
432 : : TCODE <ARG, LBUB> is *false*. TEMP_NAME1/TEMP_NAME2 are names
433 : : of the temporaries, CONDS is a vector holding the produced GIMPLE
434 : : statements, and NCONDS points to the variable holding the number of
435 : : logical comparisons. CONDS is either empty or a list ended with a
436 : : null tree. */
437 : :
438 : : static void
439 : 2813 : gen_one_condition (tree arg, int lbub,
440 : : enum tree_code tcode,
441 : : const char *temp_name1,
442 : : const char *temp_name2,
443 : : vec<gimple *> conds,
444 : : unsigned *nconds)
445 : : {
446 : 2813 : if (!HONOR_NANS (arg))
447 : 8 : tcode = comparison_code_if_no_nans (tcode);
448 : :
449 : 2813 : tree lbub_real_cst, lbub_cst, float_type;
450 : 2813 : tree temp, tempn, tempc, tempcn;
451 : 2813 : gassign *stmt1;
452 : 2813 : gassign *stmt2;
453 : 2813 : gcond *stmt3;
454 : :
455 : 2813 : float_type = TREE_TYPE (arg);
456 : 2813 : lbub_cst = build_int_cst (integer_type_node, lbub);
457 : 2813 : lbub_real_cst = build_real_from_int_cst (float_type, lbub_cst);
458 : :
459 : 2813 : temp = create_tmp_var (float_type, temp_name1);
460 : 2813 : stmt1 = gimple_build_assign (temp, arg);
461 : 2813 : tempn = make_ssa_name (temp, stmt1);
462 : 2813 : gimple_assign_set_lhs (stmt1, tempn);
463 : :
464 : 2813 : tempc = create_tmp_var (boolean_type_node, temp_name2);
465 : 2813 : stmt2 = gimple_build_assign (tempc,
466 : : fold_build2 (tcode,
467 : : boolean_type_node,
468 : : tempn, lbub_real_cst));
469 : 2813 : tempcn = make_ssa_name (tempc, stmt2);
470 : 2813 : gimple_assign_set_lhs (stmt2, tempcn);
471 : :
472 : 2813 : stmt3 = gimple_build_cond_from_tree (tempcn, NULL_TREE, NULL_TREE);
473 : 2813 : conds.quick_push (stmt1);
474 : 2813 : conds.quick_push (stmt2);
475 : 2813 : conds.quick_push (stmt3);
476 : 2813 : (*nconds)++;
477 : 2813 : }
478 : :
479 : : /* A helper function to generate GIMPLE statements for
480 : : out of input domain check. ARG is the call argument
481 : : to be runtime checked, DOMAIN holds the valid domain
482 : : for the given function, CONDS points to the vector
483 : : holding the result GIMPLE statements. *NCONDS is
484 : : the number of logical comparisons. This function
485 : : produces no more than two logical comparisons, one
486 : : for lower bound check, one for upper bound check. */
487 : :
488 : : static void
489 : 2641 : gen_conditions_for_domain (tree arg, inp_domain domain,
490 : : vec<gimple *> conds,
491 : : unsigned *nconds)
492 : : {
493 : 2641 : if (domain.has_lb)
494 : 2301 : gen_one_condition (arg, domain.lb,
495 : 2301 : (domain.is_lb_inclusive
496 : : ? UNGE_EXPR : UNGT_EXPR),
497 : : "DCE_COND_LB", "DCE_COND_LB_TEST",
498 : : conds, nconds);
499 : :
500 : 2641 : if (domain.has_ub)
501 : : {
502 : : /* Now push a separator. */
503 : 512 : if (domain.has_lb)
504 : 172 : conds.quick_push (NULL);
505 : :
506 : 512 : gen_one_condition (arg, domain.ub,
507 : 512 : (domain.is_ub_inclusive
508 : : ? UNLE_EXPR : UNLT_EXPR),
509 : : "DCE_COND_UB", "DCE_COND_UB_TEST",
510 : : conds, nconds);
511 : : }
512 : 2641 : }
513 : :
514 : :
515 : : /* A helper function to generate condition
516 : : code for the y argument in call pow (some_const, y).
517 : : See candidate selection in check_pow. Since the
518 : : candidates' base values have a limited range,
519 : : the guarded code generated for y are simple:
520 : : if (__builtin_isgreater (y, max_y))
521 : : pow (const, y);
522 : : Note max_y can be computed separately for each
523 : : const base, but in this implementation, we
524 : : choose to compute it using the max base
525 : : in the allowed range for the purpose of
526 : : simplicity. BASE is the constant base value,
527 : : EXPN is the expression for the exponent argument,
528 : : *CONDS is the vector to hold resulting statements,
529 : : and *NCONDS is the number of logical conditions. */
530 : :
531 : : static void
532 : 14 : gen_conditions_for_pow_cst_base (tree base, tree expn,
533 : : vec<gimple *> conds,
534 : : unsigned *nconds)
535 : : {
536 : 14 : inp_domain exp_domain;
537 : : /* Validate the range of the base constant to make
538 : : sure it is consistent with check_pow. */
539 : 14 : REAL_VALUE_TYPE mv;
540 : 14 : REAL_VALUE_TYPE bcv = TREE_REAL_CST (base);
541 : 14 : gcc_assert (!real_equal (&bcv, &dconst1)
542 : : && !real_less (&bcv, &dconst1));
543 : 14 : real_from_integer (&mv, TYPE_MODE (TREE_TYPE (base)), 256, UNSIGNED);
544 : 14 : gcc_assert (!real_less (&mv, &bcv));
545 : :
546 : 14 : exp_domain = get_domain (0, false, false,
547 : : 127, true, false);
548 : :
549 : 14 : gen_conditions_for_domain (expn, exp_domain,
550 : : conds, nconds);
551 : 14 : }
552 : :
553 : : /* Generate error condition code for pow calls with
554 : : non constant base values. The candidates selected
555 : : have their base argument value converted from
556 : : integer (see check_pow) value (1, 2, 4 bytes), and
557 : : the max exp value is computed based on the size
558 : : of the integer type (i.e. max possible base value).
559 : : The resulting input domain for exp argument is thus
560 : : conservative (smaller than the max value allowed by
561 : : the runtime value of the base). BASE is the integer
562 : : base value, EXPN is the expression for the exponent
563 : : argument, *CONDS is the vector to hold resulting
564 : : statements, and *NCONDS is the number of logical
565 : : conditions. */
566 : :
567 : : static void
568 : 7 : gen_conditions_for_pow_int_base (tree base, tree expn,
569 : : vec<gimple *> conds,
570 : : unsigned *nconds)
571 : : {
572 : 7 : gimple *base_def;
573 : 7 : tree base_val0;
574 : 7 : tree int_type;
575 : 7 : tree temp, tempn;
576 : 7 : tree cst0;
577 : 7 : gimple *stmt1, *stmt2;
578 : 7 : int bit_sz, max_exp;
579 : 7 : inp_domain exp_domain;
580 : :
581 : 7 : base_def = SSA_NAME_DEF_STMT (base);
582 : 7 : base_val0 = gimple_assign_rhs1 (base_def);
583 : 7 : int_type = TREE_TYPE (base_val0);
584 : 7 : bit_sz = TYPE_PRECISION (int_type);
585 : 7 : gcc_assert (bit_sz > 0
586 : : && bit_sz <= MAX_BASE_INT_BIT_SIZE);
587 : :
588 : : /* Determine the max exp argument value according to
589 : : the size of the base integer. The max exp value
590 : : is conservatively estimated assuming IEEE754 double
591 : : precision format. */
592 : 7 : if (bit_sz == 8)
593 : : max_exp = 128;
594 : : else if (bit_sz == 16)
595 : : max_exp = 64;
596 : : else
597 : : {
598 : 0 : gcc_assert (bit_sz == MAX_BASE_INT_BIT_SIZE);
599 : : max_exp = 32;
600 : : }
601 : :
602 : : /* For pow ((double)x, y), generate the following conditions:
603 : : cond 1:
604 : : temp1 = x;
605 : : if (__builtin_islessequal (temp1, 0))
606 : :
607 : : cond 2:
608 : : temp2 = y;
609 : : if (__builtin_isgreater (temp2, max_exp_real_cst)) */
610 : :
611 : : /* Generate condition in reverse order -- first
612 : : the condition for the exp argument. */
613 : :
614 : 7 : exp_domain = get_domain (0, false, false,
615 : : max_exp, true, true);
616 : :
617 : 7 : gen_conditions_for_domain (expn, exp_domain,
618 : : conds, nconds);
619 : :
620 : : /* Now generate condition for the base argument.
621 : : Note it does not use the helper function
622 : : gen_conditions_for_domain because the base
623 : : type is integer. */
624 : :
625 : : /* Push a separator. */
626 : 7 : conds.quick_push (NULL);
627 : :
628 : 7 : temp = create_tmp_var (int_type, "DCE_COND1");
629 : 7 : cst0 = build_int_cst (int_type, 0);
630 : 7 : stmt1 = gimple_build_assign (temp, base_val0);
631 : 7 : tempn = make_ssa_name (temp, stmt1);
632 : 7 : gimple_assign_set_lhs (stmt1, tempn);
633 : 7 : stmt2 = gimple_build_cond (GT_EXPR, tempn, cst0, NULL_TREE, NULL_TREE);
634 : :
635 : 7 : conds.quick_push (stmt1);
636 : 7 : conds.quick_push (stmt2);
637 : 7 : (*nconds)++;
638 : 7 : }
639 : :
640 : : /* Method to generate conditional statements for guarding conditionally
641 : : dead calls to pow. One or more statements can be generated for
642 : : each logical condition. Statement groups of different conditions
643 : : are separated by a NULL tree and they are stored in the vec
644 : : conds. The number of logical conditions are stored in *nconds.
645 : :
646 : : See C99 standard, 7.12.7.4:2, for description of pow (x, y).
647 : : The precise condition for domain errors are complex. In this
648 : : implementation, a simplified (but conservative) valid domain
649 : : for x and y are used: x is positive to avoid dom errors, while
650 : : y is smaller than a upper bound (depending on x) to avoid range
651 : : errors. Runtime code is generated to check x (if not constant)
652 : : and y against the valid domain. If it is out, jump to the call,
653 : : otherwise the call is bypassed. POW_CALL is the call statement,
654 : : *CONDS is a vector holding the resulting condition statements,
655 : : and *NCONDS is the number of logical conditions. */
656 : :
657 : : static void
658 : 21 : gen_conditions_for_pow (gcall *pow_call, vec<gimple *> conds,
659 : : unsigned *nconds)
660 : : {
661 : 21 : tree base, expn;
662 : 21 : enum tree_code bc;
663 : :
664 : 21 : gcc_checking_assert (check_pow (pow_call));
665 : :
666 : 21 : *nconds = 0;
667 : :
668 : 21 : base = gimple_call_arg (pow_call, 0);
669 : 21 : expn = gimple_call_arg (pow_call, 1);
670 : :
671 : 21 : bc = TREE_CODE (base);
672 : :
673 : 21 : if (bc == REAL_CST)
674 : 14 : gen_conditions_for_pow_cst_base (base, expn, conds, nconds);
675 : 7 : else if (bc == SSA_NAME)
676 : 7 : gen_conditions_for_pow_int_base (base, expn, conds, nconds);
677 : : else
678 : 0 : gcc_unreachable ();
679 : 21 : }
680 : :
681 : : /* A helper routine to help computing the valid input domain
682 : : for a builtin function. See C99 7.12.7 for details. In this
683 : : implementation, we only handle single region domain. The
684 : : resulting region can be conservative (smaller) than the actual
685 : : one and rounded to integers. Some of the bounds are documented
686 : : in the standard, while other limit constants are computed
687 : : assuming IEEE floating point format (for SF and DF modes).
688 : : Since IEEE only sets minimum requirements for long double format,
689 : : different long double formats exist under different implementations
690 : : (e.g, 64 bit double precision (DF), 80 bit double-extended
691 : : precision (XF), and 128 bit quad precision (TF) ). For simplicity,
692 : : in this implementation, the computed bounds for long double assume
693 : : 64 bit format (DF) except when it is IEEE quad or extended with the same
694 : : emax, and are therefore sometimes conservative. Another assumption is
695 : : that single precision float type is always SF mode, and double type is DF
696 : : mode. This function is quite implementation specific, so it may not be
697 : : suitable to be part of builtins.cc. This needs to be revisited later
698 : : to see if it can be leveraged in x87 assembly expansion. */
699 : :
700 : : static inp_domain
701 : 2620 : get_no_error_domain (enum built_in_function fnc)
702 : : {
703 : 2698 : switch (fnc)
704 : : {
705 : : /* Trig functions: return [-1, +1] */
706 : 68 : CASE_FLT_FN (BUILT_IN_ACOS):
707 : 68 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOS):
708 : 68 : CASE_FLT_FN (BUILT_IN_ACOSPI):
709 : 68 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOSPI):
710 : 68 : CASE_FLT_FN (BUILT_IN_ASIN):
711 : 68 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASIN):
712 : 68 : CASE_FLT_FN (BUILT_IN_ASINPI):
713 : 68 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ASINPI):
714 : 68 : return get_domain (-1, true, true,
715 : : 1, true, true);
716 : : /* Hyperbolic functions. */
717 : 42 : CASE_FLT_FN (BUILT_IN_ACOSH):
718 : 42 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ACOSH):
719 : : /* acosh: [1, +inf) */
720 : 42 : return get_domain (1, true, true,
721 : : 1, false, false);
722 : 36 : CASE_FLT_FN (BUILT_IN_ATANH):
723 : 36 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_ATANH):
724 : : /* atanh: (-1, +1) */
725 : 36 : return get_domain (-1, true, false,
726 : : 1, true, false);
727 : 0 : case BUILT_IN_COSHF16:
728 : 0 : case BUILT_IN_SINHF16:
729 : : /* coshf16: (-11, +11) */
730 : 0 : return get_domain (-11, true, false,
731 : : 11, true, false);
732 : 14 : case BUILT_IN_COSHF:
733 : 14 : case BUILT_IN_SINHF:
734 : 14 : case BUILT_IN_COSHF32:
735 : 14 : case BUILT_IN_SINHF32:
736 : : /* coshf: (-89, +89) */
737 : 14 : return get_domain (-89, true, false,
738 : : 89, true, false);
739 : 36 : case BUILT_IN_COSH:
740 : 36 : case BUILT_IN_SINH:
741 : 36 : case BUILT_IN_COSHF64:
742 : 36 : case BUILT_IN_SINHF64:
743 : 36 : case BUILT_IN_COSHF32X:
744 : 36 : case BUILT_IN_SINHF32X:
745 : : /* cosh: (-710, +710) */
746 : 36 : return get_domain (-710, true, false,
747 : : 710, true, false);
748 : 18 : case BUILT_IN_COSHF128:
749 : 18 : case BUILT_IN_SINHF128:
750 : : /* coshf128: (-11357, +11357) */
751 : 18 : return get_domain (-11357, true, false,
752 : : 11357, true, false);
753 : 12 : case BUILT_IN_COSHL:
754 : 12 : case BUILT_IN_SINHL:
755 : 12 : if (REAL_MODE_FORMAT (TYPE_MODE (long_double_type_node))->emax == 16384)
756 : : return get_no_error_domain (BUILT_IN_COSHF128);
757 : 0 : return get_no_error_domain (BUILT_IN_COSH);
758 : 2 : case BUILT_IN_COSHF64X:
759 : 2 : case BUILT_IN_SINHF64X:
760 : 2 : if (REAL_MODE_FORMAT (TYPE_MODE (float64x_type_node))->emax == 16384)
761 : : return get_no_error_domain (BUILT_IN_COSHF128);
762 : 0 : return get_no_error_domain (BUILT_IN_COSH);
763 : : /* Log functions: (0, +inf) */
764 : 137 : CASE_FLT_FN (BUILT_IN_LOG):
765 : 137 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG):
766 : 137 : CASE_FLT_FN (BUILT_IN_LOG2):
767 : 137 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG2):
768 : 137 : CASE_FLT_FN (BUILT_IN_LOG10):
769 : 137 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG10):
770 : 137 : return get_domain (0, true, false,
771 : : 0, false, false);
772 : 33 : CASE_FLT_FN (BUILT_IN_LOG1P):
773 : 33 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_LOG1P):
774 : 33 : return get_domain (-1, true, false,
775 : : 0, false, false);
776 : : /* Exp functions. */
777 : 0 : case BUILT_IN_EXPF16:
778 : 0 : case BUILT_IN_EXPM1F16:
779 : : /* expf16: (-inf, 11) */
780 : 0 : return get_domain (-1, false, false,
781 : : 11, true, false);
782 : 60 : case BUILT_IN_EXPF:
783 : 60 : case BUILT_IN_EXPM1F:
784 : 60 : case BUILT_IN_EXPF32:
785 : 60 : case BUILT_IN_EXPM1F32:
786 : : /* expf: (-inf, 88) */
787 : 60 : return get_domain (-1, false, false,
788 : : 88, true, false);
789 : 158 : case BUILT_IN_EXP:
790 : 158 : case BUILT_IN_EXPM1:
791 : 158 : case BUILT_IN_EXPF64:
792 : 158 : case BUILT_IN_EXPM1F64:
793 : 158 : case BUILT_IN_EXPF32X:
794 : 158 : case BUILT_IN_EXPM1F32X:
795 : : /* exp: (-inf, 709) */
796 : 158 : return get_domain (-1, false, false,
797 : : 709, true, false);
798 : 61 : case BUILT_IN_EXPF128:
799 : 61 : case BUILT_IN_EXPM1F128:
800 : : /* expf128: (-inf, 11356) */
801 : 61 : return get_domain (-1, false, false,
802 : : 11356, true, false);
803 : 57 : case BUILT_IN_EXPL:
804 : 57 : case BUILT_IN_EXPM1L:
805 : 57 : if (REAL_MODE_FORMAT (TYPE_MODE (long_double_type_node))->emax == 16384)
806 : : return get_no_error_domain (BUILT_IN_EXPF128);
807 : 0 : return get_no_error_domain (BUILT_IN_EXP);
808 : 1 : case BUILT_IN_EXPF64X:
809 : 1 : case BUILT_IN_EXPM1F64X:
810 : 1 : if (REAL_MODE_FORMAT (TYPE_MODE (float64x_type_node))->emax == 16384)
811 : : return get_no_error_domain (BUILT_IN_EXPF128);
812 : 0 : return get_no_error_domain (BUILT_IN_EXP);
813 : 0 : case BUILT_IN_EXP2F16:
814 : : /* exp2f16: (-inf, 16) */
815 : 0 : return get_domain (-1, false, false,
816 : : 16, true, false);
817 : 7 : case BUILT_IN_EXP2F:
818 : 7 : case BUILT_IN_EXP2F32:
819 : : /* exp2f: (-inf, 128) */
820 : 7 : return get_domain (-1, false, false,
821 : : 128, true, false);
822 : 18 : case BUILT_IN_EXP2:
823 : 18 : case BUILT_IN_EXP2F64:
824 : 18 : case BUILT_IN_EXP2F32X:
825 : : /* exp2: (-inf, 1024) */
826 : 18 : return get_domain (-1, false, false,
827 : : 1024, true, false);
828 : 8 : case BUILT_IN_EXP2F128:
829 : : /* exp2f128: (-inf, 16384) */
830 : 8 : return get_domain (-1, false, false,
831 : : 16384, true, false);
832 : 5 : case BUILT_IN_EXP2L:
833 : 5 : if (REAL_MODE_FORMAT (TYPE_MODE (long_double_type_node))->emax == 16384)
834 : : return get_no_error_domain (BUILT_IN_EXP2F128);
835 : 0 : return get_no_error_domain (BUILT_IN_EXP2);
836 : 1 : case BUILT_IN_EXP2F64X:
837 : 1 : if (REAL_MODE_FORMAT (TYPE_MODE (float64x_type_node))->emax == 16384)
838 : : return get_no_error_domain (BUILT_IN_EXP2F128);
839 : 0 : return get_no_error_domain (BUILT_IN_EXP2);
840 : 1 : case BUILT_IN_EXP10F:
841 : 1 : case BUILT_IN_POW10F:
842 : : /* exp10f: (-inf, 38) */
843 : 1 : return get_domain (-1, false, false,
844 : : 38, true, false);
845 : 5 : case BUILT_IN_EXP10:
846 : 5 : case BUILT_IN_POW10:
847 : : /* exp10: (-inf, 308) */
848 : 5 : return get_domain (-1, false, false,
849 : : 308, true, false);
850 : 1 : case BUILT_IN_EXP10L:
851 : 1 : case BUILT_IN_POW10L:
852 : 1 : if (REAL_MODE_FORMAT (TYPE_MODE (long_double_type_node))->emax == 16384)
853 : : /* exp10l: (-inf, 4932) */
854 : 1 : return get_domain (-1, false, false,
855 : : 4932, true, false);
856 : : return get_no_error_domain (BUILT_IN_EXP10);
857 : : /* sqrt: [0, +inf) */
858 : 1917 : CASE_FLT_FN (BUILT_IN_SQRT):
859 : 1917 : CASE_FLT_FN_FLOATN_NX (BUILT_IN_SQRT):
860 : 1917 : return get_domain (0, true, true,
861 : : 0, false, false);
862 : 0 : default:
863 : 0 : gcc_unreachable ();
864 : : }
865 : :
866 : : gcc_unreachable ();
867 : : }
868 : :
869 : : /* The function to generate shrink wrap conditions for a partially
870 : : dead builtin call whose return value is not used anywhere,
871 : : but has to be kept live due to potential error condition.
872 : : BI_CALL is the builtin call, CONDS is the vector of statements
873 : : for condition code, NCODES is the pointer to the number of
874 : : logical conditions. Statements belonging to different logical
875 : : condition are separated by NULL tree in the vector. */
876 : :
877 : : static void
878 : 2641 : gen_shrink_wrap_conditions (gcall *bi_call, const vec<gimple *> &conds,
879 : : unsigned int *nconds)
880 : : {
881 : 2641 : gcall *call;
882 : 2641 : tree fn;
883 : 2641 : enum built_in_function fnc;
884 : :
885 : 2641 : gcc_assert (nconds && conds.exists ());
886 : 2641 : gcc_assert (conds.length () == 0);
887 : 2641 : gcc_assert (is_gimple_call (bi_call));
888 : :
889 : 2641 : call = bi_call;
890 : 2641 : fn = gimple_call_fndecl (call);
891 : 2641 : gcc_assert (fn && fndecl_built_in_p (fn));
892 : 2641 : fnc = DECL_FUNCTION_CODE (fn);
893 : 2641 : *nconds = 0;
894 : :
895 : 2641 : if (fnc == BUILT_IN_POW)
896 : 21 : gen_conditions_for_pow (call, conds, nconds);
897 : : else
898 : : {
899 : 2620 : tree arg;
900 : 2620 : inp_domain domain = get_no_error_domain (fnc);
901 : 2620 : *nconds = 0;
902 : 2620 : arg = gimple_call_arg (bi_call, 0);
903 : 2620 : gen_conditions_for_domain (arg, domain, conds, nconds);
904 : : }
905 : :
906 : 2641 : return;
907 : : }
908 : :
909 : : /* Shrink-wrap BI_CALL so that it is only called when one of the NCONDS
910 : : conditions in CONDS is false. Also move BI_NEWCALL to a new basic block
911 : : when it is non-null, it is called while all of the CONDS are true. */
912 : :
913 : : static void
914 : 2780 : shrink_wrap_one_built_in_call_with_conds (gcall *bi_call,
915 : : const vec <gimple *> &conds,
916 : : unsigned int nconds,
917 : : gcall *bi_newcall = NULL)
918 : : {
919 : 2780 : gimple_stmt_iterator bi_call_bsi;
920 : 2780 : basic_block bi_call_bb, bi_newcall_bb, join_tgt_bb, guard_bb;
921 : 2780 : edge join_tgt_in_edge_from_call, join_tgt_in_edge_fall_thru;
922 : 2780 : edge bi_call_in_edge0, guard_bb_in_edge;
923 : 2780 : unsigned tn_cond_stmts;
924 : 2780 : unsigned ci;
925 : 2780 : gimple *cond_expr = NULL;
926 : 2780 : gimple *cond_expr_start;
927 : :
928 : : /* The cfg we want to create looks like this:
929 : : [guard n-1] <- guard_bb (old block)
930 : : | \
931 : : | [guard n-2] }
932 : : | / \ }
933 : : | / ... } new blocks
934 : : | / [guard 0] }
935 : : | / / | }
936 : : [call] | <- bi_call_bb }
937 : : \ [newcall] <-bi_newcall_bb}
938 : : \ |
939 : : [join] <- join_tgt_bb (old iff call must end bb)
940 : : possible EH edges (only if [join] is old)
941 : :
942 : : When [join] is new, the immediate dominators for these blocks are:
943 : :
944 : : 1. [guard n-1]: unchanged
945 : : 2. [call]: [guard n-1]
946 : : 3. [newcall]: [guard 0]
947 : : 4. [guard m]: [guard m+1] for 0 <= m <= n-2
948 : : 5. [join]: [guard n-1]
949 : :
950 : : We punt for the more complex case of [join] being old and
951 : : simply free the dominance info. We also punt on postdominators,
952 : : which aren't expected to be available at this point anyway. */
953 : 2780 : bi_call_bb = gimple_bb (bi_call);
954 : :
955 : : /* Now find the join target bb -- split bi_call_bb if needed. */
956 : 2780 : if (stmt_ends_bb_p (bi_call))
957 : : {
958 : : /* We checked that there was a fallthrough edge in
959 : : can_guard_call_p. */
960 : 0 : join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs);
961 : 0 : gcc_assert (join_tgt_in_edge_from_call);
962 : : /* We don't want to handle PHIs. */
963 : 0 : if (EDGE_COUNT (join_tgt_in_edge_from_call->dest->preds) > 1)
964 : 0 : join_tgt_bb = split_edge (join_tgt_in_edge_from_call);
965 : : else
966 : : {
967 : 0 : join_tgt_bb = join_tgt_in_edge_from_call->dest;
968 : : /* We may have degenerate PHIs in the destination. Propagate
969 : : those out. */
970 : 0 : for (gphi_iterator i = gsi_start_phis (join_tgt_bb); !gsi_end_p (i);)
971 : : {
972 : 0 : gphi *phi = i.phi ();
973 : 0 : replace_uses_by (gimple_phi_result (phi),
974 : : gimple_phi_arg_def (phi, 0));
975 : 0 : remove_phi_node (&i, true);
976 : : }
977 : : }
978 : : }
979 : : else
980 : : {
981 : 2780 : join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call);
982 : 2780 : join_tgt_bb = join_tgt_in_edge_from_call->dest;
983 : : }
984 : :
985 : 2780 : bi_call_bsi = gsi_for_stmt (bi_call);
986 : :
987 : : /* Now it is time to insert the first conditional expression
988 : : into bi_call_bb and split this bb so that bi_call is
989 : : shrink-wrapped. */
990 : 2780 : tn_cond_stmts = conds.length ();
991 : 2780 : cond_expr = NULL;
992 : 2780 : cond_expr_start = conds[0];
993 : 10846 : for (ci = 0; ci < tn_cond_stmts; ci++)
994 : : {
995 : 8245 : gimple *c = conds[ci];
996 : 8245 : gcc_assert (c || ci != 0);
997 : 8245 : if (!c)
998 : : break;
999 : 8066 : gsi_insert_before (&bi_call_bsi, c, GSI_SAME_STMT);
1000 : 8066 : cond_expr = c;
1001 : : }
1002 : 2780 : ci++;
1003 : 2780 : gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND);
1004 : :
1005 : 2780 : typedef std::pair<edge, edge> edge_pair;
1006 : 2780 : auto_vec<edge_pair, 8> edges;
1007 : :
1008 : 2780 : bi_call_in_edge0 = split_block (bi_call_bb, cond_expr);
1009 : 2780 : bi_call_in_edge0->flags &= ~EDGE_FALLTHRU;
1010 : 2780 : bi_call_in_edge0->flags |= EDGE_FALSE_VALUE;
1011 : 2780 : guard_bb = bi_call_bb;
1012 : 2780 : bi_call_bb = bi_call_in_edge0->dest;
1013 : 2780 : join_tgt_in_edge_fall_thru = make_edge (guard_bb, join_tgt_bb,
1014 : : EDGE_TRUE_VALUE);
1015 : :
1016 : 2780 : edges.reserve (nconds);
1017 : 2780 : edges.quick_push (edge_pair (bi_call_in_edge0, join_tgt_in_edge_fall_thru));
1018 : :
1019 : : /* Code generation for the rest of the conditions */
1020 : 2959 : for (unsigned int i = 1; i < nconds; ++i)
1021 : : {
1022 : 179 : unsigned ci0;
1023 : 179 : edge bi_call_in_edge;
1024 : 179 : gimple_stmt_iterator guard_bsi = gsi_for_stmt (cond_expr_start);
1025 : 179 : ci0 = ci;
1026 : 179 : cond_expr_start = conds[ci0];
1027 : 709 : for (; ci < tn_cond_stmts; ci++)
1028 : : {
1029 : 530 : gimple *c = conds[ci];
1030 : 530 : gcc_assert (c || ci != ci0);
1031 : 530 : if (!c)
1032 : : break;
1033 : 530 : gsi_insert_before (&guard_bsi, c, GSI_SAME_STMT);
1034 : 530 : cond_expr = c;
1035 : : }
1036 : 179 : ci++;
1037 : 179 : gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND);
1038 : 179 : guard_bb_in_edge = split_block (guard_bb, cond_expr);
1039 : 179 : guard_bb_in_edge->flags &= ~EDGE_FALLTHRU;
1040 : 179 : guard_bb_in_edge->flags |= EDGE_TRUE_VALUE;
1041 : :
1042 : 179 : bi_call_in_edge = make_edge (guard_bb, bi_call_bb, EDGE_FALSE_VALUE);
1043 : 179 : edges.quick_push (edge_pair (bi_call_in_edge, guard_bb_in_edge));
1044 : : }
1045 : :
1046 : : /* Move BI_NEWCALL to new basic block when it is non-null. */
1047 : 2780 : if (bi_newcall)
1048 : : {
1049 : : /* Get bi_newcall_bb by split join_tgt_in_edge_fall_thru edge,
1050 : : and move BI_NEWCALL to bi_newcall_bb. */
1051 : 1665 : bi_newcall_bb = split_edge (join_tgt_in_edge_fall_thru);
1052 : 1665 : gimple_stmt_iterator to_gsi = gsi_start_bb (bi_newcall_bb);
1053 : 1665 : gimple_stmt_iterator from_gsi = gsi_for_stmt (bi_newcall);
1054 : 1665 : gsi_move_before (&from_gsi, &to_gsi);
1055 : 1665 : join_tgt_in_edge_fall_thru = EDGE_SUCC (bi_newcall_bb, 0);
1056 : 1665 : join_tgt_bb = join_tgt_in_edge_fall_thru->dest;
1057 : :
1058 : 1665 : tree bi_newcall_lhs = gimple_call_lhs (bi_newcall);
1059 : 1665 : tree bi_call_lhs = gimple_call_lhs (bi_call);
1060 : 1665 : if (!bi_call_lhs)
1061 : : {
1062 : 1665 : bi_call_lhs = copy_ssa_name (bi_newcall_lhs);
1063 : 1665 : gimple_call_set_lhs (bi_call, bi_call_lhs);
1064 : 1665 : SSA_NAME_DEF_STMT (bi_call_lhs) = bi_call;
1065 : : }
1066 : :
1067 : : /* Create phi node for lhs of BI_CALL and BI_NEWCALL. */
1068 : 1665 : gphi *new_phi = create_phi_node (copy_ssa_name (bi_newcall_lhs),
1069 : : join_tgt_bb);
1070 : 1665 : SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (new_phi))
1071 : 1665 : = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (bi_newcall_lhs);
1072 : 1665 : add_phi_arg (new_phi, bi_call_lhs, join_tgt_in_edge_from_call,
1073 : : gimple_location (bi_call));
1074 : 1665 : add_phi_arg (new_phi, bi_newcall_lhs, join_tgt_in_edge_fall_thru,
1075 : : gimple_location (bi_newcall));
1076 : :
1077 : : /* Replace all use of original return value with result of phi node. */
1078 : 1665 : use_operand_p use_p;
1079 : 1665 : gimple *use_stmt;
1080 : 1665 : imm_use_iterator iterator;
1081 : 5850 : FOR_EACH_IMM_USE_STMT (use_stmt, iterator, bi_newcall_lhs)
1082 : 4185 : if (use_stmt != new_phi)
1083 : 7560 : FOR_EACH_IMM_USE_ON_STMT (use_p, iterator)
1084 : 4185 : SET_USE (use_p, PHI_RESULT (new_phi));
1085 : : }
1086 : :
1087 : : /* Now update the probability and profile information, processing the
1088 : : guards in order of execution.
1089 : :
1090 : : There are two approaches we could take here. On the one hand we
1091 : : could assign a probability of X to the call block and distribute
1092 : : that probability among its incoming edges. On the other hand we
1093 : : could assign a probability of X to each individual call edge.
1094 : :
1095 : : The choice only affects calls that have more than one condition.
1096 : : In those cases, the second approach would give the call block
1097 : : a greater probability than the first. However, the difference
1098 : : is only small, and our chosen X is a pure guess anyway.
1099 : :
1100 : : Here we take the second approach because it's slightly simpler
1101 : : and because it's easy to see that it doesn't lose profile counts. */
1102 : 2780 : bi_call_bb->count = profile_count::zero ();
1103 : 8519 : while (!edges.is_empty ())
1104 : : {
1105 : 2959 : edge_pair e = edges.pop ();
1106 : 2959 : edge call_edge = e.first;
1107 : 2959 : edge nocall_edge = e.second;
1108 : 2959 : basic_block src_bb = call_edge->src;
1109 : 2959 : gcc_assert (src_bb == nocall_edge->src);
1110 : :
1111 : 2959 : call_edge->probability = profile_probability::very_unlikely ();
1112 : 5918 : nocall_edge->probability = profile_probability::always ()
1113 : 2959 : - call_edge->probability;
1114 : :
1115 : 2959 : bi_call_bb->count += call_edge->count ();
1116 : :
1117 : 2959 : if (nocall_edge->dest != join_tgt_bb)
1118 : 1844 : nocall_edge->dest->count = src_bb->count - bi_call_bb->count;
1119 : : }
1120 : :
1121 : 2780 : if (dom_info_available_p (CDI_DOMINATORS))
1122 : : {
1123 : : /* The split_blocks leave [guard 0] as the immediate dominator
1124 : : of [call] and [call] as the immediate dominator of [join].
1125 : : Fix them up. */
1126 : 2780 : set_immediate_dominator (CDI_DOMINATORS, bi_call_bb, guard_bb);
1127 : 2780 : set_immediate_dominator (CDI_DOMINATORS, join_tgt_bb, guard_bb);
1128 : : }
1129 : :
1130 : 2780 : if (dump_file && (dump_flags & TDF_DETAILS))
1131 : : {
1132 : 138 : location_t loc;
1133 : 138 : loc = gimple_location (bi_call);
1134 : 138 : fprintf (dump_file,
1135 : : "%s:%d: note: function call is shrink-wrapped"
1136 : : " into error conditions.\n",
1137 : 276 : LOCATION_FILE (loc), LOCATION_LINE (loc));
1138 : : }
1139 : 2780 : }
1140 : :
1141 : : /* Shrink-wrap BI_CALL so that it is only called when it might set errno
1142 : : (but is always called if it would set errno). */
1143 : :
1144 : : static void
1145 : 976 : shrink_wrap_one_built_in_call (gcall *bi_call)
1146 : : {
1147 : 976 : unsigned nconds = 0;
1148 : 976 : auto_vec<gimple *, 12> conds;
1149 : 976 : gen_shrink_wrap_conditions (bi_call, conds, &nconds);
1150 : 976 : gcc_assert (nconds != 0);
1151 : 976 : shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds);
1152 : 976 : }
1153 : :
1154 : : /* Return true if built-in function call CALL could be implemented using
1155 : : a combination of an internal function to compute the result and a
1156 : : separate call to set errno. */
1157 : :
1158 : : static bool
1159 : 365875 : can_use_internal_fn (gcall *call)
1160 : : {
1161 : : /* Only replace calls that set errno. */
1162 : 901907 : if (!gimple_vdef (call))
1163 : : return false;
1164 : :
1165 : : /* See whether there is an internal function for this built-in. */
1166 : 171961 : if (replacement_internal_fn (call) == IFN_LAST)
1167 : : return false;
1168 : :
1169 : : /* See whether we can catch all cases where errno would be set,
1170 : : while still avoiding the call in most cases. */
1171 : 1899 : if (!can_test_argument_range (call)
1172 : 1899 : && !edom_only_function (call))
1173 : : return false;
1174 : :
1175 : : return true;
1176 : : }
1177 : :
1178 : : /* Implement built-in function call CALL using an internal function. */
1179 : :
1180 : : static void
1181 : 1804 : use_internal_fn (gcall *call)
1182 : : {
1183 : : /* We'll be inserting another call with the same arguments after the
1184 : : lhs has been set, so prevent any possible coalescing failure from
1185 : : having both values live at once. See PR 71020. */
1186 : 1804 : replace_abnormal_ssa_names (call);
1187 : :
1188 : 1804 : unsigned nconds = 0;
1189 : 1804 : auto_vec<gimple *, 12> conds;
1190 : 1804 : bool is_arg_conds = false;
1191 : 1804 : if (can_test_argument_range (call))
1192 : : {
1193 : 1665 : gen_shrink_wrap_conditions (call, conds, &nconds);
1194 : 1665 : is_arg_conds = true;
1195 : 1665 : gcc_assert (nconds != 0);
1196 : : }
1197 : : else
1198 : 139 : gcc_assert (edom_only_function (call));
1199 : :
1200 : 1804 : internal_fn ifn = replacement_internal_fn (call);
1201 : 1804 : gcc_assert (ifn != IFN_LAST);
1202 : :
1203 : : /* Construct the new call, with the same arguments as the original one. */
1204 : 1804 : auto_vec <tree, 16> args;
1205 : 1804 : unsigned int nargs = gimple_call_num_args (call);
1206 : 3746 : for (unsigned int i = 0; i < nargs; ++i)
1207 : 1942 : args.safe_push (gimple_call_arg (call, i));
1208 : 1804 : gcall *new_call = gimple_build_call_internal_vec (ifn, args);
1209 : 1804 : gimple_set_location (new_call, gimple_location (call));
1210 : 1804 : gimple_call_set_nothrow (new_call, gimple_call_nothrow_p (call));
1211 : :
1212 : : /* Transfer the LHS to the new call. */
1213 : 1804 : tree lhs = gimple_call_lhs (call);
1214 : 1804 : gimple_call_set_lhs (new_call, lhs);
1215 : 1804 : gimple_call_set_lhs (call, NULL_TREE);
1216 : 1804 : SSA_NAME_DEF_STMT (lhs) = new_call;
1217 : :
1218 : : /* Insert the new call. */
1219 : 1804 : gimple_stmt_iterator gsi = gsi_for_stmt (call);
1220 : 1804 : gsi_insert_before (&gsi, new_call, GSI_SAME_STMT);
1221 : :
1222 : 1804 : if (nconds == 0)
1223 : : {
1224 : : /* Skip the call if LHS == LHS. If we reach here, EDOM is the only
1225 : : valid errno value and it is used iff the result is NaN. */
1226 : : /* In the case of non call exceptions, with signaling NaNs, EQ_EXPR
1227 : : can throw an exception and that can't be part of the GIMPLE_COND. */
1228 : 139 : if (flag_exceptions
1229 : 51 : && cfun->can_throw_non_call_exceptions
1230 : 143 : && operation_could_trap_p (EQ_EXPR, true, false, NULL_TREE))
1231 : : {
1232 : 4 : tree b = make_ssa_name (boolean_type_node);
1233 : 4 : conds.quick_push (gimple_build_assign (b, EQ_EXPR, lhs, lhs));
1234 : 4 : conds.quick_push (gimple_build_cond (NE_EXPR, b, boolean_false_node,
1235 : : NULL_TREE, NULL_TREE));
1236 : : }
1237 : : else
1238 : 135 : conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs,
1239 : : NULL_TREE, NULL_TREE));
1240 : 139 : nconds++;
1241 : :
1242 : : /* Try replacing the original call with a direct assignment to
1243 : : errno, via an internal function. */
1244 : 139 : if (set_edom_supported_p () && !stmt_ends_bb_p (call))
1245 : : {
1246 : 0 : gimple_stmt_iterator gsi = gsi_for_stmt (call);
1247 : 0 : gcall *new_call = gimple_build_call_internal (IFN_SET_EDOM, 0);
1248 : 0 : gimple_move_vops (new_call, call);
1249 : 0 : gimple_set_location (new_call, gimple_location (call));
1250 : 0 : gsi_replace (&gsi, new_call, false);
1251 : 0 : call = new_call;
1252 : : }
1253 : : }
1254 : 1943 : shrink_wrap_one_built_in_call_with_conds (call, conds, nconds,
1255 : : is_arg_conds ? new_call : NULL);
1256 : 1804 : }
1257 : :
1258 : : /* The top level function for conditional dead code shrink
1259 : : wrapping transformation. */
1260 : :
1261 : : static void
1262 : 1133 : shrink_wrap_conditional_dead_built_in_calls (const vec<gcall *> &calls)
1263 : : {
1264 : 1133 : unsigned i = 0;
1265 : :
1266 : 1133 : unsigned n = calls.length ();
1267 : 3913 : for (; i < n ; i++)
1268 : : {
1269 : 2780 : gcall *bi_call = calls[i];
1270 : 2780 : if (gimple_call_lhs (bi_call))
1271 : 1804 : use_internal_fn (bi_call);
1272 : : else
1273 : 976 : shrink_wrap_one_built_in_call (bi_call);
1274 : : }
1275 : 1133 : }
1276 : :
1277 : : namespace {
1278 : :
1279 : : const pass_data pass_data_call_cdce =
1280 : : {
1281 : : GIMPLE_PASS, /* type */
1282 : : "cdce", /* name */
1283 : : OPTGROUP_NONE, /* optinfo_flags */
1284 : : TV_TREE_CALL_CDCE, /* tv_id */
1285 : : ( PROP_cfg | PROP_ssa ), /* properties_required */
1286 : : 0, /* properties_provided */
1287 : : 0, /* properties_destroyed */
1288 : : 0, /* todo_flags_start */
1289 : : 0, /* todo_flags_finish */
1290 : : };
1291 : :
1292 : : class pass_call_cdce : public gimple_opt_pass
1293 : : {
1294 : : public:
1295 : 285689 : pass_call_cdce (gcc::context *ctxt)
1296 : 571378 : : gimple_opt_pass (pass_data_call_cdce, ctxt)
1297 : : {}
1298 : :
1299 : : /* opt_pass methods: */
1300 : 1042778 : bool gate (function *) final override
1301 : : {
1302 : : /* The limit constants used in the implementation
1303 : : assume IEEE floating point format. Other formats
1304 : : can be supported in the future if needed. */
1305 : 1042778 : return flag_tree_builtin_call_dce != 0;
1306 : : }
1307 : :
1308 : : unsigned int execute (function *) final override;
1309 : :
1310 : : }; // class pass_call_cdce
1311 : :
1312 : : unsigned int
1313 : 1042710 : pass_call_cdce::execute (function *fun)
1314 : : {
1315 : 1042710 : basic_block bb;
1316 : 1042710 : gimple_stmt_iterator i;
1317 : 1042710 : auto_vec<gcall *> cond_dead_built_in_calls;
1318 : 11575292 : FOR_EACH_BB_FN (bb, fun)
1319 : : {
1320 : : /* Skip blocks that are being optimized for size, since our
1321 : : transformation always increases code size. */
1322 : 10532582 : if (optimize_bb_for_size_p (bb))
1323 : 2164130 : continue;
1324 : :
1325 : : /* Collect dead call candidates. */
1326 : 88927007 : for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
1327 : : {
1328 : 72190103 : gcall *stmt = dyn_cast <gcall *> (gsi_stmt (i));
1329 : 72190103 : if (stmt
1330 : 3779915 : && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)
1331 : 1104079 : && (gimple_call_lhs (stmt)
1332 : 738204 : ? can_use_internal_fn (stmt)
1333 : 372329 : : can_test_argument_range (stmt))
1334 : 72931087 : && can_guard_call_p (stmt))
1335 : : {
1336 : 2780 : if (dump_file && (dump_flags & TDF_DETAILS))
1337 : : {
1338 : 138 : fprintf (dump_file, "Found conditional dead call: ");
1339 : 138 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
1340 : 138 : fprintf (dump_file, "\n");
1341 : : }
1342 : 2780 : if (!cond_dead_built_in_calls.exists ())
1343 : 1133 : cond_dead_built_in_calls.create (64);
1344 : 2780 : cond_dead_built_in_calls.safe_push (stmt);
1345 : : }
1346 : : }
1347 : : }
1348 : :
1349 : 1042710 : if (!cond_dead_built_in_calls.exists ())
1350 : : return 0;
1351 : :
1352 : 1133 : shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls);
1353 : 1133 : free_dominance_info (CDI_POST_DOMINATORS);
1354 : : /* As we introduced new control-flow we need to insert PHI-nodes
1355 : : for the call-clobbers of the remaining call. */
1356 : 1133 : mark_virtual_operands_for_renaming (fun);
1357 : 1133 : return TODO_update_ssa;
1358 : 1042710 : }
1359 : :
1360 : : } // anon namespace
1361 : :
1362 : : gimple_opt_pass *
1363 : 285689 : make_pass_call_cdce (gcc::context *ctxt)
1364 : : {
1365 : 285689 : return new pass_call_cdce (ctxt);
1366 : : }
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