1 /* Convert tree expression to rtl instructions, for GNU compiler.
2 Copyright (C) 1988-2020 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "backend.h"
24 #include "target.h"
25 #include "rtl.h"
26 #include "tree.h"
27 #include "predict.h"
28 #include "memmodel.h"
29 #include "tm_p.h"
30 #include "optabs.h"
31 #include "emit-rtl.h"
32 #include "fold-const.h"
33 #include "stor-layout.h"
34 /* Include expr.h after insn-config.h so we get HAVE_conditional_move. */
35 #include "dojump.h"
36 #include "explow.h"
37 #include "expr.h"
38 #include "langhooks.h"
39
40 static bool prefer_and_bit_test (scalar_int_mode, int);
41 static void do_jump (tree, rtx_code_label *, rtx_code_label *,
42 profile_probability);
43 static void do_jump_by_parts_greater (scalar_int_mode, tree, tree, int,
44 rtx_code_label *, rtx_code_label *,
45 profile_probability);
46 static void do_jump_by_parts_equality (scalar_int_mode, tree, tree,
47 rtx_code_label *, rtx_code_label *,
48 profile_probability);
49 static void do_compare_and_jump (tree, tree, enum rtx_code, enum rtx_code,
50 rtx_code_label *, rtx_code_label *,
51 profile_probability);
52
53 /* At the start of a function, record that we have no previously-pushed
54 arguments waiting to be popped. */
55
56 void
init_pending_stack_adjust(void)57 init_pending_stack_adjust (void)
58 {
59 pending_stack_adjust = 0;
60 }
61
62 /* Discard any pending stack adjustment. This avoid relying on the
63 RTL optimizers to remove useless adjustments when we know the
64 stack pointer value is dead. */
65 void
discard_pending_stack_adjust(void)66 discard_pending_stack_adjust (void)
67 {
68 stack_pointer_delta -= pending_stack_adjust;
69 pending_stack_adjust = 0;
70 }
71
72 /* When exiting from function, if safe, clear out any pending stack adjust
73 so the adjustment won't get done.
74
75 Note, if the current function calls alloca, then it must have a
76 frame pointer regardless of the value of flag_omit_frame_pointer. */
77
78 void
clear_pending_stack_adjust(void)79 clear_pending_stack_adjust (void)
80 {
81 if (optimize > 0
82 && (! flag_omit_frame_pointer || cfun->calls_alloca)
83 && EXIT_IGNORE_STACK)
84 discard_pending_stack_adjust ();
85 }
86
87 /* Pop any previously-pushed arguments that have not been popped yet. */
88
89 void
do_pending_stack_adjust(void)90 do_pending_stack_adjust (void)
91 {
92 if (inhibit_defer_pop == 0)
93 {
94 if (maybe_ne (pending_stack_adjust, 0))
95 adjust_stack (gen_int_mode (pending_stack_adjust, Pmode));
96 pending_stack_adjust = 0;
97 }
98 }
99
100 /* Remember pending_stack_adjust/stack_pointer_delta.
101 To be used around code that may call do_pending_stack_adjust (),
102 but the generated code could be discarded e.g. using delete_insns_since. */
103
104 void
save_pending_stack_adjust(saved_pending_stack_adjust * save)105 save_pending_stack_adjust (saved_pending_stack_adjust *save)
106 {
107 save->x_pending_stack_adjust = pending_stack_adjust;
108 save->x_stack_pointer_delta = stack_pointer_delta;
109 }
110
111 /* Restore the saved pending_stack_adjust/stack_pointer_delta. */
112
113 void
restore_pending_stack_adjust(saved_pending_stack_adjust * save)114 restore_pending_stack_adjust (saved_pending_stack_adjust *save)
115 {
116 if (inhibit_defer_pop == 0)
117 {
118 pending_stack_adjust = save->x_pending_stack_adjust;
119 stack_pointer_delta = save->x_stack_pointer_delta;
120 }
121 }
122
123 /* Used internally by prefer_and_bit_test. */
124
125 static GTY(()) rtx and_reg;
126 static GTY(()) rtx and_test;
127 static GTY(()) rtx shift_test;
128
129 /* Compare the relative costs of "(X & (1 << BITNUM))" and "(X >> BITNUM) & 1",
130 where X is an arbitrary register of mode MODE. Return true if the former
131 is preferred. */
132
133 static bool
prefer_and_bit_test(scalar_int_mode mode,int bitnum)134 prefer_and_bit_test (scalar_int_mode mode, int bitnum)
135 {
136 bool speed_p;
137 wide_int mask = wi::set_bit_in_zero (bitnum, GET_MODE_PRECISION (mode));
138
139 if (and_test == 0)
140 {
141 /* Set up rtxes for the two variations. Use NULL as a placeholder
142 for the BITNUM-based constants. */
143 and_reg = gen_rtx_REG (mode, LAST_VIRTUAL_REGISTER + 1);
144 and_test = gen_rtx_AND (mode, and_reg, NULL);
145 shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL),
146 const1_rtx);
147 }
148 else
149 {
150 /* Change the mode of the previously-created rtxes. */
151 PUT_MODE (and_reg, mode);
152 PUT_MODE (and_test, mode);
153 PUT_MODE (shift_test, mode);
154 PUT_MODE (XEXP (shift_test, 0), mode);
155 }
156
157 /* Fill in the integers. */
158 XEXP (and_test, 1) = immed_wide_int_const (mask, mode);
159 XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum);
160
161 speed_p = optimize_insn_for_speed_p ();
162 return (rtx_cost (and_test, mode, IF_THEN_ELSE, 0, speed_p)
163 <= rtx_cost (shift_test, mode, IF_THEN_ELSE, 0, speed_p));
164 }
165
166 /* Subroutine of do_jump, dealing with exploded comparisons of the type
167 OP0 CODE OP1 . IF_FALSE_LABEL and IF_TRUE_LABEL like in do_jump.
168 PROB is probability of jump to if_true_label. */
169
170 static void
do_jump_1(enum tree_code code,tree op0,tree op1,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)171 do_jump_1 (enum tree_code code, tree op0, tree op1,
172 rtx_code_label *if_false_label, rtx_code_label *if_true_label,
173 profile_probability prob)
174 {
175 machine_mode mode;
176 rtx_code_label *drop_through_label = 0;
177 scalar_int_mode int_mode;
178
179 switch (code)
180 {
181 case EQ_EXPR:
182 {
183 tree inner_type = TREE_TYPE (op0);
184
185 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
186 != MODE_COMPLEX_FLOAT);
187 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
188 != MODE_COMPLEX_INT);
189
190 if (integer_zerop (op1))
191 do_jump (op0, if_true_label, if_false_label,
192 prob.invert ());
193 else if (is_int_mode (TYPE_MODE (inner_type), &int_mode)
194 && !can_compare_p (EQ, int_mode, ccp_jump))
195 do_jump_by_parts_equality (int_mode, op0, op1, if_false_label,
196 if_true_label, prob);
197 else
198 do_compare_and_jump (op0, op1, EQ, EQ, if_false_label, if_true_label,
199 prob);
200 break;
201 }
202
203 case NE_EXPR:
204 {
205 tree inner_type = TREE_TYPE (op0);
206
207 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
208 != MODE_COMPLEX_FLOAT);
209 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
210 != MODE_COMPLEX_INT);
211
212 if (integer_zerop (op1))
213 do_jump (op0, if_false_label, if_true_label, prob);
214 else if (is_int_mode (TYPE_MODE (inner_type), &int_mode)
215 && !can_compare_p (NE, int_mode, ccp_jump))
216 do_jump_by_parts_equality (int_mode, op0, op1, if_true_label,
217 if_false_label, prob.invert ());
218 else
219 do_compare_and_jump (op0, op1, NE, NE, if_false_label, if_true_label,
220 prob);
221 break;
222 }
223
224 case LT_EXPR:
225 mode = TYPE_MODE (TREE_TYPE (op0));
226 if (is_int_mode (mode, &int_mode)
227 && ! can_compare_p (LT, int_mode, ccp_jump))
228 do_jump_by_parts_greater (int_mode, op0, op1, 1, if_false_label,
229 if_true_label, prob);
230 else
231 do_compare_and_jump (op0, op1, LT, LTU, if_false_label, if_true_label,
232 prob);
233 break;
234
235 case LE_EXPR:
236 mode = TYPE_MODE (TREE_TYPE (op0));
237 if (is_int_mode (mode, &int_mode)
238 && ! can_compare_p (LE, int_mode, ccp_jump))
239 do_jump_by_parts_greater (int_mode, op0, op1, 0, if_true_label,
240 if_false_label, prob.invert ());
241 else
242 do_compare_and_jump (op0, op1, LE, LEU, if_false_label, if_true_label,
243 prob);
244 break;
245
246 case GT_EXPR:
247 mode = TYPE_MODE (TREE_TYPE (op0));
248 if (is_int_mode (mode, &int_mode)
249 && ! can_compare_p (GT, int_mode, ccp_jump))
250 do_jump_by_parts_greater (int_mode, op0, op1, 0, if_false_label,
251 if_true_label, prob);
252 else
253 do_compare_and_jump (op0, op1, GT, GTU, if_false_label, if_true_label,
254 prob);
255 break;
256
257 case GE_EXPR:
258 mode = TYPE_MODE (TREE_TYPE (op0));
259 if (is_int_mode (mode, &int_mode)
260 && ! can_compare_p (GE, int_mode, ccp_jump))
261 do_jump_by_parts_greater (int_mode, op0, op1, 1, if_true_label,
262 if_false_label, prob.invert ());
263 else
264 do_compare_and_jump (op0, op1, GE, GEU, if_false_label, if_true_label,
265 prob);
266 break;
267
268 case ORDERED_EXPR:
269 do_compare_and_jump (op0, op1, ORDERED, ORDERED,
270 if_false_label, if_true_label, prob);
271 break;
272
273 case UNORDERED_EXPR:
274 do_compare_and_jump (op0, op1, UNORDERED, UNORDERED,
275 if_false_label, if_true_label, prob);
276 break;
277
278 case UNLT_EXPR:
279 do_compare_and_jump (op0, op1, UNLT, UNLT, if_false_label, if_true_label,
280 prob);
281 break;
282
283 case UNLE_EXPR:
284 do_compare_and_jump (op0, op1, UNLE, UNLE, if_false_label, if_true_label,
285 prob);
286 break;
287
288 case UNGT_EXPR:
289 do_compare_and_jump (op0, op1, UNGT, UNGT, if_false_label, if_true_label,
290 prob);
291 break;
292
293 case UNGE_EXPR:
294 do_compare_and_jump (op0, op1, UNGE, UNGE, if_false_label, if_true_label,
295 prob);
296 break;
297
298 case UNEQ_EXPR:
299 do_compare_and_jump (op0, op1, UNEQ, UNEQ, if_false_label, if_true_label,
300 prob);
301 break;
302
303 case LTGT_EXPR:
304 do_compare_and_jump (op0, op1, LTGT, LTGT, if_false_label, if_true_label,
305 prob);
306 break;
307
308 case TRUTH_ANDIF_EXPR:
309 {
310 /* Spread the probability that the expression is false evenly between
311 the two conditions. So the first condition is false half the total
312 probability of being false. The second condition is false the other
313 half of the total probability of being false, so its jump has a false
314 probability of half the total, relative to the probability we
315 reached it (i.e. the first condition was true). */
316 profile_probability op0_prob = profile_probability::uninitialized ();
317 profile_probability op1_prob = profile_probability::uninitialized ();
318 if (prob.initialized_p ())
319 {
320 op1_prob = prob.invert ();
321 op0_prob = op1_prob.split (profile_probability::even ());
322 /* Get the probability that each jump below is true. */
323 op0_prob = op0_prob.invert ();
324 op1_prob = op1_prob.invert ();
325 }
326 if (if_false_label == NULL)
327 {
328 drop_through_label = gen_label_rtx ();
329 do_jump (op0, drop_through_label, NULL, op0_prob);
330 do_jump (op1, NULL, if_true_label, op1_prob);
331 }
332 else
333 {
334 do_jump (op0, if_false_label, NULL, op0_prob);
335 do_jump (op1, if_false_label, if_true_label, op1_prob);
336 }
337 break;
338 }
339
340 case TRUTH_ORIF_EXPR:
341 {
342 /* Spread the probability evenly between the two conditions. So
343 the first condition has half the total probability of being true.
344 The second condition has the other half of the total probability,
345 so its jump has a probability of half the total, relative to
346 the probability we reached it (i.e. the first condition was false). */
347 profile_probability op0_prob = profile_probability::uninitialized ();
348 profile_probability op1_prob = profile_probability::uninitialized ();
349 if (prob.initialized_p ())
350 {
351 op1_prob = prob;
352 op0_prob = op1_prob.split (profile_probability::even ());
353 }
354 if (if_true_label == NULL)
355 {
356 drop_through_label = gen_label_rtx ();
357 do_jump (op0, NULL, drop_through_label, op0_prob);
358 do_jump (op1, if_false_label, NULL, op1_prob);
359 }
360 else
361 {
362 do_jump (op0, NULL, if_true_label, op0_prob);
363 do_jump (op1, if_false_label, if_true_label, op1_prob);
364 }
365 break;
366 }
367
368 default:
369 gcc_unreachable ();
370 }
371
372 if (drop_through_label)
373 {
374 do_pending_stack_adjust ();
375 emit_label (drop_through_label);
376 }
377 }
378
379 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
380 the result is zero, or IF_TRUE_LABEL if the result is one.
381 Either of IF_FALSE_LABEL and IF_TRUE_LABEL may be zero,
382 meaning fall through in that case.
383
384 do_jump always does any pending stack adjust except when it does not
385 actually perform a jump. An example where there is no jump
386 is when EXP is `(foo (), 0)' and IF_FALSE_LABEL is null.
387
388 PROB is probability of jump to if_true_label. */
389
390 static void
do_jump(tree exp,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)391 do_jump (tree exp, rtx_code_label *if_false_label,
392 rtx_code_label *if_true_label, profile_probability prob)
393 {
394 enum tree_code code = TREE_CODE (exp);
395 rtx temp;
396 int i;
397 tree type;
398 scalar_int_mode mode;
399 rtx_code_label *drop_through_label = NULL;
400
401 switch (code)
402 {
403 case ERROR_MARK:
404 break;
405
406 case INTEGER_CST:
407 {
408 rtx_code_label *lab = integer_zerop (exp) ? if_false_label
409 : if_true_label;
410 if (lab)
411 emit_jump (lab);
412 break;
413 }
414
415 #if 0
416 /* This is not true with #pragma weak */
417 case ADDR_EXPR:
418 /* The address of something can never be zero. */
419 if (if_true_label)
420 emit_jump (if_true_label);
421 break;
422 #endif
423
424 case NOP_EXPR:
425 if (TREE_CODE (TREE_OPERAND (exp, 0)) == COMPONENT_REF
426 || TREE_CODE (TREE_OPERAND (exp, 0)) == BIT_FIELD_REF
427 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_REF
428 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_RANGE_REF)
429 goto normal;
430 /* FALLTHRU */
431 case CONVERT_EXPR:
432 /* If we are narrowing the operand, we have to do the compare in the
433 narrower mode. */
434 if ((TYPE_PRECISION (TREE_TYPE (exp))
435 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0)))))
436 goto normal;
437 /* FALLTHRU */
438 case NON_LVALUE_EXPR:
439 case ABS_EXPR:
440 case ABSU_EXPR:
441 case NEGATE_EXPR:
442 case LROTATE_EXPR:
443 case RROTATE_EXPR:
444 /* These cannot change zero->nonzero or vice versa. */
445 do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label, prob);
446 break;
447
448 case TRUTH_NOT_EXPR:
449 do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label,
450 prob.invert ());
451 break;
452
453 case COND_EXPR:
454 {
455 rtx_code_label *label1 = gen_label_rtx ();
456 if (!if_true_label || !if_false_label)
457 {
458 drop_through_label = gen_label_rtx ();
459 if (!if_true_label)
460 if_true_label = drop_through_label;
461 if (!if_false_label)
462 if_false_label = drop_through_label;
463 }
464
465 do_pending_stack_adjust ();
466 do_jump (TREE_OPERAND (exp, 0), label1, NULL,
467 profile_probability::uninitialized ());
468 do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label, prob);
469 emit_label (label1);
470 do_jump (TREE_OPERAND (exp, 2), if_false_label, if_true_label, prob);
471 break;
472 }
473
474 case COMPOUND_EXPR:
475 /* Lowered by gimplify.c. */
476 gcc_unreachable ();
477
478 case MINUS_EXPR:
479 /* Nonzero iff operands of minus differ. */
480 code = NE_EXPR;
481
482 /* FALLTHRU */
483 case EQ_EXPR:
484 case NE_EXPR:
485 case LT_EXPR:
486 case LE_EXPR:
487 case GT_EXPR:
488 case GE_EXPR:
489 case ORDERED_EXPR:
490 case UNORDERED_EXPR:
491 case UNLT_EXPR:
492 case UNLE_EXPR:
493 case UNGT_EXPR:
494 case UNGE_EXPR:
495 case UNEQ_EXPR:
496 case LTGT_EXPR:
497 case TRUTH_ANDIF_EXPR:
498 case TRUTH_ORIF_EXPR:
499 other_code:
500 do_jump_1 (code, TREE_OPERAND (exp, 0), TREE_OPERAND (exp, 1),
501 if_false_label, if_true_label, prob);
502 break;
503
504 case BIT_AND_EXPR:
505 /* fold_single_bit_test() converts (X & (1 << C)) into (X >> C) & 1.
506 See if the former is preferred for jump tests and restore it
507 if so. */
508 if (integer_onep (TREE_OPERAND (exp, 1)))
509 {
510 tree exp0 = TREE_OPERAND (exp, 0);
511 rtx_code_label *set_label, *clr_label;
512 profile_probability setclr_prob = prob;
513
514 /* Strip narrowing integral type conversions. */
515 while (CONVERT_EXPR_P (exp0)
516 && TREE_OPERAND (exp0, 0) != error_mark_node
517 && TYPE_PRECISION (TREE_TYPE (exp0))
518 <= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp0, 0))))
519 exp0 = TREE_OPERAND (exp0, 0);
520
521 /* "exp0 ^ 1" inverts the sense of the single bit test. */
522 if (TREE_CODE (exp0) == BIT_XOR_EXPR
523 && integer_onep (TREE_OPERAND (exp0, 1)))
524 {
525 exp0 = TREE_OPERAND (exp0, 0);
526 clr_label = if_true_label;
527 set_label = if_false_label;
528 setclr_prob = prob.invert ();
529 }
530 else
531 {
532 clr_label = if_false_label;
533 set_label = if_true_label;
534 }
535
536 if (TREE_CODE (exp0) == RSHIFT_EXPR)
537 {
538 tree arg = TREE_OPERAND (exp0, 0);
539 tree shift = TREE_OPERAND (exp0, 1);
540 tree argtype = TREE_TYPE (arg);
541 if (TREE_CODE (shift) == INTEGER_CST
542 && compare_tree_int (shift, 0) >= 0
543 && compare_tree_int (shift, HOST_BITS_PER_WIDE_INT) < 0
544 && prefer_and_bit_test (SCALAR_INT_TYPE_MODE (argtype),
545 TREE_INT_CST_LOW (shift)))
546 {
547 unsigned HOST_WIDE_INT mask
548 = HOST_WIDE_INT_1U << TREE_INT_CST_LOW (shift);
549 do_jump (build2 (BIT_AND_EXPR, argtype, arg,
550 build_int_cstu (argtype, mask)),
551 clr_label, set_label, setclr_prob);
552 break;
553 }
554 }
555 }
556
557 /* If we are AND'ing with a small constant, do this comparison in the
558 smallest type that fits. If the machine doesn't have comparisons
559 that small, it will be converted back to the wider comparison.
560 This helps if we are testing the sign bit of a narrower object.
561 combine can't do this for us because it can't know whether a
562 ZERO_EXTRACT or a compare in a smaller mode exists, but we do. */
563
564 if (! SLOW_BYTE_ACCESS
565 && TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST
566 && TYPE_PRECISION (TREE_TYPE (exp)) <= HOST_BITS_PER_WIDE_INT
567 && (i = tree_floor_log2 (TREE_OPERAND (exp, 1))) >= 0
568 && int_mode_for_size (i + 1, 0).exists (&mode)
569 && (type = lang_hooks.types.type_for_mode (mode, 1)) != 0
570 && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp))
571 && have_insn_for (COMPARE, TYPE_MODE (type)))
572 {
573 do_jump (fold_convert (type, exp), if_false_label, if_true_label,
574 prob);
575 break;
576 }
577
578 if (TYPE_PRECISION (TREE_TYPE (exp)) > 1
579 || TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST)
580 goto normal;
581
582 /* Boolean comparisons can be compiled as TRUTH_AND_EXPR. */
583 /* FALLTHRU */
584
585 case TRUTH_AND_EXPR:
586 /* High branch cost, expand as the bitwise AND of the conditions.
587 Do the same if the RHS has side effects, because we're effectively
588 turning a TRUTH_AND_EXPR into a TRUTH_ANDIF_EXPR. */
589 if (BRANCH_COST (optimize_insn_for_speed_p (),
590 false) >= 4
591 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1)))
592 goto normal;
593 code = TRUTH_ANDIF_EXPR;
594 goto other_code;
595
596 case BIT_IOR_EXPR:
597 case TRUTH_OR_EXPR:
598 /* High branch cost, expand as the bitwise OR of the conditions.
599 Do the same if the RHS has side effects, because we're effectively
600 turning a TRUTH_OR_EXPR into a TRUTH_ORIF_EXPR. */
601 if (BRANCH_COST (optimize_insn_for_speed_p (), false) >= 4
602 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1)))
603 goto normal;
604 code = TRUTH_ORIF_EXPR;
605 goto other_code;
606
607 /* Fall through and generate the normal code. */
608 default:
609 normal:
610 temp = expand_normal (exp);
611 do_pending_stack_adjust ();
612 /* The RTL optimizers prefer comparisons against pseudos. */
613 if (GET_CODE (temp) == SUBREG)
614 {
615 /* Compare promoted variables in their promoted mode. */
616 if (SUBREG_PROMOTED_VAR_P (temp)
617 && REG_P (XEXP (temp, 0)))
618 temp = XEXP (temp, 0);
619 else
620 temp = copy_to_reg (temp);
621 }
622 do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)),
623 NE, TYPE_UNSIGNED (TREE_TYPE (exp)),
624 GET_MODE (temp), NULL_RTX,
625 if_false_label, if_true_label, prob);
626 }
627
628 if (drop_through_label)
629 {
630 do_pending_stack_adjust ();
631 emit_label (drop_through_label);
632 }
633 }
634
635 /* Compare OP0 with OP1, word at a time, in mode MODE.
636 UNSIGNEDP says to do unsigned comparison.
637 Jump to IF_TRUE_LABEL if OP0 is greater, IF_FALSE_LABEL otherwise. */
638
639 static void
do_jump_by_parts_greater_rtx(scalar_int_mode mode,int unsignedp,rtx op0,rtx op1,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)640 do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
641 rtx op1, rtx_code_label *if_false_label,
642 rtx_code_label *if_true_label,
643 profile_probability prob)
644 {
645 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
646 rtx_code_label *drop_through_label = 0;
647 bool drop_through_if_true = false, drop_through_if_false = false;
648 enum rtx_code code = GT;
649 int i;
650
651 if (! if_true_label || ! if_false_label)
652 drop_through_label = gen_label_rtx ();
653 if (! if_true_label)
654 {
655 if_true_label = drop_through_label;
656 drop_through_if_true = true;
657 }
658 if (! if_false_label)
659 {
660 if_false_label = drop_through_label;
661 drop_through_if_false = true;
662 }
663
664 /* Deal with the special case 0 > x: only one comparison is necessary and
665 we reverse it to avoid jumping to the drop-through label. */
666 if (op0 == const0_rtx && drop_through_if_true && !drop_through_if_false)
667 {
668 code = LE;
669 if_true_label = if_false_label;
670 if_false_label = drop_through_label;
671 prob = prob.invert ();
672 }
673
674 /* Compare a word at a time, high order first. */
675 for (i = 0; i < nwords; i++)
676 {
677 rtx op0_word, op1_word;
678
679 if (WORDS_BIG_ENDIAN)
680 {
681 op0_word = operand_subword_force (op0, i, mode);
682 op1_word = operand_subword_force (op1, i, mode);
683 }
684 else
685 {
686 op0_word = operand_subword_force (op0, nwords - 1 - i, mode);
687 op1_word = operand_subword_force (op1, nwords - 1 - i, mode);
688 }
689
690 /* All but high-order word must be compared as unsigned. */
691 do_compare_rtx_and_jump (op0_word, op1_word, code, (unsignedp || i > 0),
692 word_mode, NULL_RTX, NULL, if_true_label,
693 prob);
694
695 /* Emit only one comparison for 0. Do not emit the last cond jump. */
696 if (op0 == const0_rtx || i == nwords - 1)
697 break;
698
699 /* Consider lower words only if these are equal. */
700 do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode,
701 NULL_RTX, NULL, if_false_label,
702 prob.invert ());
703 }
704
705 if (!drop_through_if_false)
706 emit_jump (if_false_label);
707 if (drop_through_label)
708 emit_label (drop_through_label);
709 }
710
711 /* Given a comparison expression EXP for values too wide to be compared
712 with one insn, test the comparison and jump to the appropriate label.
713 The code of EXP is ignored; we always test GT if SWAP is 0,
714 and LT if SWAP is 1. MODE is the mode of the two operands. */
715
716 static void
do_jump_by_parts_greater(scalar_int_mode mode,tree treeop0,tree treeop1,int swap,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)717 do_jump_by_parts_greater (scalar_int_mode mode, tree treeop0, tree treeop1,
718 int swap, rtx_code_label *if_false_label,
719 rtx_code_label *if_true_label,
720 profile_probability prob)
721 {
722 rtx op0 = expand_normal (swap ? treeop1 : treeop0);
723 rtx op1 = expand_normal (swap ? treeop0 : treeop1);
724 int unsignedp = TYPE_UNSIGNED (TREE_TYPE (treeop0));
725
726 do_jump_by_parts_greater_rtx (mode, unsignedp, op0, op1, if_false_label,
727 if_true_label, prob);
728 }
729
730 /* Jump according to whether OP0 is 0. We assume that OP0 has an integer
731 mode, MODE, that is too wide for the available compare insns. Either
732 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL
733 to indicate drop through. */
734
735 static void
do_jump_by_parts_zero_rtx(scalar_int_mode mode,rtx op0,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)736 do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
737 rtx_code_label *if_false_label,
738 rtx_code_label *if_true_label,
739 profile_probability prob)
740 {
741 int nwords = GET_MODE_SIZE (mode) / UNITS_PER_WORD;
742 rtx part;
743 int i;
744 rtx_code_label *drop_through_label = NULL;
745
746 /* The fastest way of doing this comparison on almost any machine is to
747 "or" all the words and compare the result. If all have to be loaded
748 from memory and this is a very wide item, it's possible this may
749 be slower, but that's highly unlikely. */
750
751 part = gen_reg_rtx (word_mode);
752 emit_move_insn (part, operand_subword_force (op0, 0, mode));
753 for (i = 1; i < nwords && part != 0; i++)
754 part = expand_binop (word_mode, ior_optab, part,
755 operand_subword_force (op0, i, mode),
756 part, 1, OPTAB_WIDEN);
757
758 if (part != 0)
759 {
760 do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode,
761 NULL_RTX, if_false_label, if_true_label, prob);
762 return;
763 }
764
765 /* If we couldn't do the "or" simply, do this with a series of compares. */
766 if (! if_false_label)
767 if_false_label = drop_through_label = gen_label_rtx ();
768
769 for (i = 0; i < nwords; i++)
770 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
771 const0_rtx, EQ, 1, word_mode, NULL_RTX,
772 if_false_label, NULL, prob);
773
774 if (if_true_label)
775 emit_jump (if_true_label);
776
777 if (drop_through_label)
778 emit_label (drop_through_label);
779 }
780
781 /* Test for the equality of two RTX expressions OP0 and OP1 in mode MODE,
782 where MODE is an integer mode too wide to be compared with one insn.
783 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL_RTX
784 to indicate drop through. */
785
786 static void
do_jump_by_parts_equality_rtx(scalar_int_mode mode,rtx op0,rtx op1,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)787 do_jump_by_parts_equality_rtx (scalar_int_mode mode, rtx op0, rtx op1,
788 rtx_code_label *if_false_label,
789 rtx_code_label *if_true_label,
790 profile_probability prob)
791 {
792 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
793 rtx_code_label *drop_through_label = NULL;
794 int i;
795
796 if (op1 == const0_rtx)
797 {
798 do_jump_by_parts_zero_rtx (mode, op0, if_false_label, if_true_label,
799 prob);
800 return;
801 }
802 else if (op0 == const0_rtx)
803 {
804 do_jump_by_parts_zero_rtx (mode, op1, if_false_label, if_true_label,
805 prob);
806 return;
807 }
808
809 if (! if_false_label)
810 drop_through_label = if_false_label = gen_label_rtx ();
811
812 for (i = 0; i < nwords; i++)
813 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
814 operand_subword_force (op1, i, mode),
815 EQ, 0, word_mode, NULL_RTX,
816 if_false_label, NULL, prob);
817
818 if (if_true_label)
819 emit_jump (if_true_label);
820 if (drop_through_label)
821 emit_label (drop_through_label);
822 }
823
824 /* Given an EQ_EXPR expression EXP for values too wide to be compared
825 with one insn, test the comparison and jump to the appropriate label.
826 MODE is the mode of the two operands. */
827
828 static void
do_jump_by_parts_equality(scalar_int_mode mode,tree treeop0,tree treeop1,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)829 do_jump_by_parts_equality (scalar_int_mode mode, tree treeop0, tree treeop1,
830 rtx_code_label *if_false_label,
831 rtx_code_label *if_true_label,
832 profile_probability prob)
833 {
834 rtx op0 = expand_normal (treeop0);
835 rtx op1 = expand_normal (treeop1);
836 do_jump_by_parts_equality_rtx (mode, op0, op1, if_false_label,
837 if_true_label, prob);
838 }
839
840 /* Split a comparison into two others, the second of which has the other
841 "orderedness". The first is always ORDERED or UNORDERED if MODE
842 does not honor NaNs (which means that it can be skipped in that case;
843 see do_compare_rtx_and_jump).
844
845 The two conditions are written in *CODE1 and *CODE2. Return true if
846 the conditions must be ANDed, false if they must be ORed. */
847
848 bool
split_comparison(enum rtx_code code,machine_mode mode,enum rtx_code * code1,enum rtx_code * code2)849 split_comparison (enum rtx_code code, machine_mode mode,
850 enum rtx_code *code1, enum rtx_code *code2)
851 {
852 switch (code)
853 {
854 case LT:
855 *code1 = ORDERED;
856 *code2 = UNLT;
857 return true;
858 case LE:
859 *code1 = ORDERED;
860 *code2 = UNLE;
861 return true;
862 case GT:
863 *code1 = ORDERED;
864 *code2 = UNGT;
865 return true;
866 case GE:
867 *code1 = ORDERED;
868 *code2 = UNGE;
869 return true;
870 case EQ:
871 *code1 = ORDERED;
872 *code2 = UNEQ;
873 return true;
874 case NE:
875 *code1 = UNORDERED;
876 *code2 = LTGT;
877 return false;
878 case UNLT:
879 *code1 = UNORDERED;
880 *code2 = LT;
881 return false;
882 case UNLE:
883 *code1 = UNORDERED;
884 *code2 = LE;
885 return false;
886 case UNGT:
887 *code1 = UNORDERED;
888 *code2 = GT;
889 return false;
890 case UNGE:
891 *code1 = UNORDERED;
892 *code2 = GE;
893 return false;
894 case UNEQ:
895 *code1 = UNORDERED;
896 *code2 = EQ;
897 return false;
898 case LTGT:
899 /* Do not turn a trapping comparison into a non-trapping one. */
900 if (HONOR_NANS (mode))
901 {
902 *code1 = LT;
903 *code2 = GT;
904 return false;
905 }
906 else
907 {
908 *code1 = ORDERED;
909 *code2 = NE;
910 return true;
911 }
912 default:
913 gcc_unreachable ();
914 }
915 }
916
917 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.
918 PROB is probability of jump to LABEL. */
919
920 void
jumpif(tree exp,rtx_code_label * label,profile_probability prob)921 jumpif (tree exp, rtx_code_label *label, profile_probability prob)
922 {
923 do_jump (exp, NULL, label, prob);
924 }
925
926 /* Similar to jumpif but dealing with exploded comparisons of the type
927 OP0 CODE OP1 . LABEL and PROB are like in jumpif. */
928
929 void
jumpif_1(enum tree_code code,tree op0,tree op1,rtx_code_label * label,profile_probability prob)930 jumpif_1 (enum tree_code code, tree op0, tree op1, rtx_code_label *label,
931 profile_probability prob)
932 {
933 do_jump_1 (code, op0, op1, NULL, label, prob);
934 }
935
936 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.
937 PROB is probability of jump to LABEL. */
938
939 void
jumpifnot(tree exp,rtx_code_label * label,profile_probability prob)940 jumpifnot (tree exp, rtx_code_label *label, profile_probability prob)
941 {
942 do_jump (exp, label, NULL, prob.invert ());
943 }
944
945 /* Similar to jumpifnot but dealing with exploded comparisons of the type
946 OP0 CODE OP1 . LABEL and PROB are like in jumpifnot. */
947
948 void
jumpifnot_1(enum tree_code code,tree op0,tree op1,rtx_code_label * label,profile_probability prob)949 jumpifnot_1 (enum tree_code code, tree op0, tree op1, rtx_code_label *label,
950 profile_probability prob)
951 {
952 do_jump_1 (code, op0, op1, label, NULL, prob.invert ());
953 }
954
955 /* Like do_compare_and_jump but expects the values to compare as two rtx's.
956 The decision as to signed or unsigned comparison must be made by the caller.
957
958 If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
959 compared. */
960
961 void
do_compare_rtx_and_jump(rtx op0,rtx op1,enum rtx_code code,int unsignedp,machine_mode mode,rtx size,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)962 do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
963 machine_mode mode, rtx size,
964 rtx_code_label *if_false_label,
965 rtx_code_label *if_true_label,
966 profile_probability prob)
967 {
968 rtx tem;
969 rtx_code_label *dummy_label = NULL;
970
971 /* Reverse the comparison if that is safe and we want to jump if it is
972 false. Also convert to the reverse comparison if the target can
973 implement it. */
974 if ((! if_true_label
975 || ! can_compare_p (code, mode, ccp_jump))
976 && (! FLOAT_MODE_P (mode)
977 || code == ORDERED || code == UNORDERED
978 || (! HONOR_NANS (mode) && (code == LTGT || code == UNEQ))
979 || (! HONOR_SNANS (mode) && (code == EQ || code == NE))))
980 {
981 enum rtx_code rcode;
982 if (FLOAT_MODE_P (mode))
983 rcode = reverse_condition_maybe_unordered (code);
984 else
985 rcode = reverse_condition (code);
986
987 /* Canonicalize to UNORDERED for the libcall. */
988 if (can_compare_p (rcode, mode, ccp_jump)
989 || (code == ORDERED && ! can_compare_p (ORDERED, mode, ccp_jump)))
990 {
991 std::swap (if_true_label, if_false_label);
992 code = rcode;
993 prob = prob.invert ();
994 }
995 }
996
997 /* If one operand is constant, make it the second one. Only do this
998 if the other operand is not constant as well. */
999
1000 if (swap_commutative_operands_p (op0, op1))
1001 {
1002 std::swap (op0, op1);
1003 code = swap_condition (code);
1004 }
1005
1006 do_pending_stack_adjust ();
1007
1008 code = unsignedp ? unsigned_condition (code) : code;
1009 if ((tem = simplify_relational_operation (code, mode, VOIDmode,
1010 op0, op1)) != 0)
1011 {
1012 if (CONSTANT_P (tem))
1013 {
1014 rtx_code_label *label = (tem == const0_rtx
1015 || tem == CONST0_RTX (mode))
1016 ? if_false_label : if_true_label;
1017 if (label)
1018 emit_jump (label);
1019 return;
1020 }
1021
1022 code = GET_CODE (tem);
1023 mode = GET_MODE (tem);
1024 op0 = XEXP (tem, 0);
1025 op1 = XEXP (tem, 1);
1026 unsignedp = (code == GTU || code == LTU || code == GEU || code == LEU);
1027 }
1028
1029 if (! if_true_label)
1030 dummy_label = if_true_label = gen_label_rtx ();
1031
1032 scalar_int_mode int_mode;
1033 if (is_int_mode (mode, &int_mode)
1034 && ! can_compare_p (code, int_mode, ccp_jump))
1035 {
1036 switch (code)
1037 {
1038 case LTU:
1039 do_jump_by_parts_greater_rtx (int_mode, 1, op1, op0,
1040 if_false_label, if_true_label, prob);
1041 break;
1042
1043 case LEU:
1044 do_jump_by_parts_greater_rtx (int_mode, 1, op0, op1,
1045 if_true_label, if_false_label,
1046 prob.invert ());
1047 break;
1048
1049 case GTU:
1050 do_jump_by_parts_greater_rtx (int_mode, 1, op0, op1,
1051 if_false_label, if_true_label, prob);
1052 break;
1053
1054 case GEU:
1055 do_jump_by_parts_greater_rtx (int_mode, 1, op1, op0,
1056 if_true_label, if_false_label,
1057 prob.invert ());
1058 break;
1059
1060 case LT:
1061 do_jump_by_parts_greater_rtx (int_mode, 0, op1, op0,
1062 if_false_label, if_true_label, prob);
1063 break;
1064
1065 case LE:
1066 do_jump_by_parts_greater_rtx (int_mode, 0, op0, op1,
1067 if_true_label, if_false_label,
1068 prob.invert ());
1069 break;
1070
1071 case GT:
1072 do_jump_by_parts_greater_rtx (int_mode, 0, op0, op1,
1073 if_false_label, if_true_label, prob);
1074 break;
1075
1076 case GE:
1077 do_jump_by_parts_greater_rtx (int_mode, 0, op1, op0,
1078 if_true_label, if_false_label,
1079 prob.invert ());
1080 break;
1081
1082 case EQ:
1083 do_jump_by_parts_equality_rtx (int_mode, op0, op1, if_false_label,
1084 if_true_label, prob);
1085 break;
1086
1087 case NE:
1088 do_jump_by_parts_equality_rtx (int_mode, op0, op1, if_true_label,
1089 if_false_label,
1090 prob.invert ());
1091 break;
1092
1093 default:
1094 gcc_unreachable ();
1095 }
1096 }
1097 else
1098 {
1099 if (SCALAR_FLOAT_MODE_P (mode)
1100 && ! can_compare_p (code, mode, ccp_jump)
1101 && can_compare_p (swap_condition (code), mode, ccp_jump))
1102 {
1103 code = swap_condition (code);
1104 std::swap (op0, op1);
1105 }
1106 else if (SCALAR_FLOAT_MODE_P (mode)
1107 && ! can_compare_p (code, mode, ccp_jump)
1108 /* Never split ORDERED and UNORDERED.
1109 These must be implemented. */
1110 && (code != ORDERED && code != UNORDERED)
1111 /* Split a floating-point comparison if
1112 we can jump on other conditions... */
1113 && (have_insn_for (COMPARE, mode)
1114 /* ... or if there is no libcall for it. */
1115 || code_to_optab (code) == unknown_optab))
1116 {
1117 enum rtx_code first_code;
1118 bool and_them = split_comparison (code, mode, &first_code, &code);
1119
1120 /* If there are no NaNs, the first comparison should always fall
1121 through. */
1122 if (!HONOR_NANS (mode))
1123 gcc_assert (first_code == (and_them ? ORDERED : UNORDERED));
1124
1125 else
1126 {
1127 profile_probability cprob
1128 = profile_probability::guessed_always ();
1129 if (first_code == UNORDERED)
1130 cprob = cprob.apply_scale (1, 100);
1131 else if (first_code == ORDERED)
1132 cprob = cprob.apply_scale (99, 100);
1133 else
1134 cprob = profile_probability::even ();
1135 /* We want to split:
1136 if (x) goto t; // prob;
1137 into
1138 if (a) goto t; // first_prob;
1139 if (b) goto t; // prob;
1140 such that the overall probability of jumping to t
1141 remains the same and first_prob is prob * cprob. */
1142 if (and_them)
1143 {
1144 rtx_code_label *dest_label;
1145 prob = prob.invert ();
1146 profile_probability first_prob = prob.split (cprob).invert ();
1147 prob = prob.invert ();
1148 /* If we only jump if true, just bypass the second jump. */
1149 if (! if_false_label)
1150 {
1151 if (! dummy_label)
1152 dummy_label = gen_label_rtx ();
1153 dest_label = dummy_label;
1154 }
1155 else
1156 dest_label = if_false_label;
1157 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
1158 size, dest_label, NULL, first_prob);
1159 }
1160 else
1161 {
1162 profile_probability first_prob = prob.split (cprob);
1163 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
1164 size, NULL, if_true_label, first_prob);
1165 }
1166 }
1167 }
1168
1169 emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp,
1170 if_true_label, prob);
1171 }
1172
1173 if (if_false_label)
1174 emit_jump (if_false_label);
1175 if (dummy_label)
1176 emit_label (dummy_label);
1177 }
1178
1179 /* Generate code for a comparison expression EXP (including code to compute
1180 the values to be compared) and a conditional jump to IF_FALSE_LABEL and/or
1181 IF_TRUE_LABEL. One of the labels can be NULL_RTX, in which case the
1182 generated code will drop through.
1183 SIGNED_CODE should be the rtx operation for this comparison for
1184 signed data; UNSIGNED_CODE, likewise for use if data is unsigned.
1185
1186 We force a stack adjustment unless there are currently
1187 things pushed on the stack that aren't yet used. */
1188
1189 static void
do_compare_and_jump(tree treeop0,tree treeop1,enum rtx_code signed_code,enum rtx_code unsigned_code,rtx_code_label * if_false_label,rtx_code_label * if_true_label,profile_probability prob)1190 do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
1191 enum rtx_code unsigned_code,
1192 rtx_code_label *if_false_label,
1193 rtx_code_label *if_true_label, profile_probability prob)
1194 {
1195 rtx op0, op1;
1196 tree type;
1197 machine_mode mode;
1198 int unsignedp;
1199 enum rtx_code code;
1200
1201 /* Don't crash if the comparison was erroneous. */
1202 op0 = expand_normal (treeop0);
1203 if (TREE_CODE (treeop0) == ERROR_MARK)
1204 return;
1205
1206 op1 = expand_normal (treeop1);
1207 if (TREE_CODE (treeop1) == ERROR_MARK)
1208 return;
1209
1210 type = TREE_TYPE (treeop0);
1211 if (TREE_CODE (treeop0) == INTEGER_CST
1212 && (TREE_CODE (treeop1) != INTEGER_CST
1213 || (GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (type))
1214 > GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (TREE_TYPE (treeop1))))))
1215 /* op0 might have been replaced by promoted constant, in which
1216 case the type of second argument should be used. */
1217 type = TREE_TYPE (treeop1);
1218 mode = TYPE_MODE (type);
1219 unsignedp = TYPE_UNSIGNED (type);
1220 code = unsignedp ? unsigned_code : signed_code;
1221
1222 /* If function pointers need to be "canonicalized" before they can
1223 be reliably compared, then canonicalize them. Canonicalize the
1224 expression when one of the operands is a function pointer. This
1225 handles the case where the other operand is a void pointer. See
1226 PR middle-end/17564. */
1227 if (targetm.have_canonicalize_funcptr_for_compare ()
1228 && ((POINTER_TYPE_P (TREE_TYPE (treeop0))
1229 && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop0))))
1230 || (POINTER_TYPE_P (TREE_TYPE (treeop1))
1231 && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop1))))))
1232 {
1233 rtx new_op0 = gen_reg_rtx (mode);
1234 rtx new_op1 = gen_reg_rtx (mode);
1235
1236 emit_insn (targetm.gen_canonicalize_funcptr_for_compare (new_op0, op0));
1237 op0 = new_op0;
1238
1239 emit_insn (targetm.gen_canonicalize_funcptr_for_compare (new_op1, op1));
1240 op1 = new_op1;
1241 }
1242
1243 do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode,
1244 ((mode == BLKmode)
1245 ? expr_size (treeop0) : NULL_RTX),
1246 if_false_label, if_true_label, prob);
1247 }
1248
1249 #include "gt-dojump.h"
1250