P0646R1 Improving the Return Value of Erase-Like Algorithms I
[official-gcc.git] / gcc / dojump.c
blob88cc96ae85ae2e799c1af8969b9d7835fb74d907
1 /* Convert tree expression to rtl instructions, for GNU compiler.
2 Copyright (C) 1988-2018 Free Software Foundation, Inc.
4 This file is part of GCC.
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.
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.
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/>. */
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"
40 static bool prefer_and_bit_test (scalar_int_mode, int);
41 static void do_jump_by_parts_greater (scalar_int_mode, tree, tree, int,
42 rtx_code_label *, rtx_code_label *,
43 profile_probability);
44 static void do_jump_by_parts_equality (scalar_int_mode, tree, tree,
45 rtx_code_label *, rtx_code_label *,
46 profile_probability);
47 static void do_compare_and_jump (tree, tree, enum rtx_code, enum rtx_code,
48 rtx_code_label *, rtx_code_label *,
49 profile_probability);
51 /* At the start of a function, record that we have no previously-pushed
52 arguments waiting to be popped. */
54 void
55 init_pending_stack_adjust (void)
57 pending_stack_adjust = 0;
60 /* Discard any pending stack adjustment. This avoid relying on the
61 RTL optimizers to remove useless adjustments when we know the
62 stack pointer value is dead. */
63 void
64 discard_pending_stack_adjust (void)
66 stack_pointer_delta -= pending_stack_adjust;
67 pending_stack_adjust = 0;
70 /* When exiting from function, if safe, clear out any pending stack adjust
71 so the adjustment won't get done.
73 Note, if the current function calls alloca, then it must have a
74 frame pointer regardless of the value of flag_omit_frame_pointer. */
76 void
77 clear_pending_stack_adjust (void)
79 if (optimize > 0
80 && (! flag_omit_frame_pointer || cfun->calls_alloca)
81 && EXIT_IGNORE_STACK)
82 discard_pending_stack_adjust ();
85 /* Pop any previously-pushed arguments that have not been popped yet. */
87 void
88 do_pending_stack_adjust (void)
90 if (inhibit_defer_pop == 0)
92 if (maybe_ne (pending_stack_adjust, 0))
93 adjust_stack (gen_int_mode (pending_stack_adjust, Pmode));
94 pending_stack_adjust = 0;
98 /* Remember pending_stack_adjust/stack_pointer_delta.
99 To be used around code that may call do_pending_stack_adjust (),
100 but the generated code could be discarded e.g. using delete_insns_since. */
102 void
103 save_pending_stack_adjust (saved_pending_stack_adjust *save)
105 save->x_pending_stack_adjust = pending_stack_adjust;
106 save->x_stack_pointer_delta = stack_pointer_delta;
109 /* Restore the saved pending_stack_adjust/stack_pointer_delta. */
111 void
112 restore_pending_stack_adjust (saved_pending_stack_adjust *save)
114 if (inhibit_defer_pop == 0)
116 pending_stack_adjust = save->x_pending_stack_adjust;
117 stack_pointer_delta = save->x_stack_pointer_delta;
121 /* Expand conditional expressions. */
123 /* Generate code to evaluate EXP and jump to LABEL if the value is zero. */
125 void
126 jumpifnot (tree exp, rtx_code_label *label, profile_probability prob)
128 do_jump (exp, label, NULL, prob.invert ());
131 void
132 jumpifnot_1 (enum tree_code code, tree op0, tree op1, rtx_code_label *label,
133 profile_probability prob)
135 do_jump_1 (code, op0, op1, label, NULL, prob.invert ());
138 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero. */
140 void
141 jumpif (tree exp, rtx_code_label *label, profile_probability prob)
143 do_jump (exp, NULL, label, prob);
146 void
147 jumpif_1 (enum tree_code code, tree op0, tree op1,
148 rtx_code_label *label, profile_probability prob)
150 do_jump_1 (code, op0, op1, NULL, label, prob);
153 /* Used internally by prefer_and_bit_test. */
155 static GTY(()) rtx and_reg;
156 static GTY(()) rtx and_test;
157 static GTY(()) rtx shift_test;
159 /* Compare the relative costs of "(X & (1 << BITNUM))" and "(X >> BITNUM) & 1",
160 where X is an arbitrary register of mode MODE. Return true if the former
161 is preferred. */
163 static bool
164 prefer_and_bit_test (scalar_int_mode mode, int bitnum)
166 bool speed_p;
167 wide_int mask = wi::set_bit_in_zero (bitnum, GET_MODE_PRECISION (mode));
169 if (and_test == 0)
171 /* Set up rtxes for the two variations. Use NULL as a placeholder
172 for the BITNUM-based constants. */
173 and_reg = gen_rtx_REG (mode, LAST_VIRTUAL_REGISTER + 1);
174 and_test = gen_rtx_AND (mode, and_reg, NULL);
175 shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL),
176 const1_rtx);
178 else
180 /* Change the mode of the previously-created rtxes. */
181 PUT_MODE (and_reg, mode);
182 PUT_MODE (and_test, mode);
183 PUT_MODE (shift_test, mode);
184 PUT_MODE (XEXP (shift_test, 0), mode);
187 /* Fill in the integers. */
188 XEXP (and_test, 1) = immed_wide_int_const (mask, mode);
189 XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum);
191 speed_p = optimize_insn_for_speed_p ();
192 return (rtx_cost (and_test, mode, IF_THEN_ELSE, 0, speed_p)
193 <= rtx_cost (shift_test, mode, IF_THEN_ELSE, 0, speed_p));
196 /* Subroutine of do_jump, dealing with exploded comparisons of the type
197 OP0 CODE OP1 . IF_FALSE_LABEL and IF_TRUE_LABEL like in do_jump.
198 PROB is probability of jump to if_true_label. */
200 void
201 do_jump_1 (enum tree_code code, tree op0, tree op1,
202 rtx_code_label *if_false_label, rtx_code_label *if_true_label,
203 profile_probability prob)
205 machine_mode mode;
206 rtx_code_label *drop_through_label = 0;
207 scalar_int_mode int_mode;
209 switch (code)
211 case EQ_EXPR:
213 tree inner_type = TREE_TYPE (op0);
215 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
216 != MODE_COMPLEX_FLOAT);
217 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
218 != MODE_COMPLEX_INT);
220 if (integer_zerop (op1))
221 do_jump (op0, if_true_label, if_false_label,
222 prob.invert ());
223 else if (is_int_mode (TYPE_MODE (inner_type), &int_mode)
224 && !can_compare_p (EQ, int_mode, ccp_jump))
225 do_jump_by_parts_equality (int_mode, op0, op1, if_false_label,
226 if_true_label, prob);
227 else
228 do_compare_and_jump (op0, op1, EQ, EQ, if_false_label, if_true_label,
229 prob);
230 break;
233 case NE_EXPR:
235 tree inner_type = TREE_TYPE (op0);
237 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
238 != MODE_COMPLEX_FLOAT);
239 gcc_assert (GET_MODE_CLASS (TYPE_MODE (inner_type))
240 != MODE_COMPLEX_INT);
242 if (integer_zerop (op1))
243 do_jump (op0, if_false_label, if_true_label, prob);
244 else if (is_int_mode (TYPE_MODE (inner_type), &int_mode)
245 && !can_compare_p (NE, int_mode, ccp_jump))
246 do_jump_by_parts_equality (int_mode, op0, op1, if_true_label,
247 if_false_label, prob.invert ());
248 else
249 do_compare_and_jump (op0, op1, NE, NE, if_false_label, if_true_label,
250 prob);
251 break;
254 case LT_EXPR:
255 mode = TYPE_MODE (TREE_TYPE (op0));
256 if (is_int_mode (mode, &int_mode)
257 && ! can_compare_p (LT, int_mode, ccp_jump))
258 do_jump_by_parts_greater (int_mode, op0, op1, 1, if_false_label,
259 if_true_label, prob);
260 else
261 do_compare_and_jump (op0, op1, LT, LTU, if_false_label, if_true_label,
262 prob);
263 break;
265 case LE_EXPR:
266 mode = TYPE_MODE (TREE_TYPE (op0));
267 if (is_int_mode (mode, &int_mode)
268 && ! can_compare_p (LE, int_mode, ccp_jump))
269 do_jump_by_parts_greater (int_mode, op0, op1, 0, if_true_label,
270 if_false_label, prob.invert ());
271 else
272 do_compare_and_jump (op0, op1, LE, LEU, if_false_label, if_true_label,
273 prob);
274 break;
276 case GT_EXPR:
277 mode = TYPE_MODE (TREE_TYPE (op0));
278 if (is_int_mode (mode, &int_mode)
279 && ! can_compare_p (GT, int_mode, ccp_jump))
280 do_jump_by_parts_greater (int_mode, op0, op1, 0, if_false_label,
281 if_true_label, prob);
282 else
283 do_compare_and_jump (op0, op1, GT, GTU, if_false_label, if_true_label,
284 prob);
285 break;
287 case GE_EXPR:
288 mode = TYPE_MODE (TREE_TYPE (op0));
289 if (is_int_mode (mode, &int_mode)
290 && ! can_compare_p (GE, int_mode, ccp_jump))
291 do_jump_by_parts_greater (int_mode, op0, op1, 1, if_true_label,
292 if_false_label, prob.invert ());
293 else
294 do_compare_and_jump (op0, op1, GE, GEU, if_false_label, if_true_label,
295 prob);
296 break;
298 case ORDERED_EXPR:
299 do_compare_and_jump (op0, op1, ORDERED, ORDERED,
300 if_false_label, if_true_label, prob);
301 break;
303 case UNORDERED_EXPR:
304 do_compare_and_jump (op0, op1, UNORDERED, UNORDERED,
305 if_false_label, if_true_label, prob);
306 break;
308 case UNLT_EXPR:
309 do_compare_and_jump (op0, op1, UNLT, UNLT, if_false_label, if_true_label,
310 prob);
311 break;
313 case UNLE_EXPR:
314 do_compare_and_jump (op0, op1, UNLE, UNLE, if_false_label, if_true_label,
315 prob);
316 break;
318 case UNGT_EXPR:
319 do_compare_and_jump (op0, op1, UNGT, UNGT, if_false_label, if_true_label,
320 prob);
321 break;
323 case UNGE_EXPR:
324 do_compare_and_jump (op0, op1, UNGE, UNGE, if_false_label, if_true_label,
325 prob);
326 break;
328 case UNEQ_EXPR:
329 do_compare_and_jump (op0, op1, UNEQ, UNEQ, if_false_label, if_true_label,
330 prob);
331 break;
333 case LTGT_EXPR:
334 do_compare_and_jump (op0, op1, LTGT, LTGT, if_false_label, if_true_label,
335 prob);
336 break;
338 case TRUTH_ANDIF_EXPR:
340 /* Spread the probability that the expression is false evenly between
341 the two conditions. So the first condition is false half the total
342 probability of being false. The second condition is false the other
343 half of the total probability of being false, so its jump has a false
344 probability of half the total, relative to the probability we
345 reached it (i.e. the first condition was true). */
346 profile_probability op0_prob = profile_probability::uninitialized ();
347 profile_probability op1_prob = profile_probability::uninitialized ();
348 if (prob.initialized_p ())
350 op1_prob = prob.invert ();
351 op0_prob = op1_prob.split (profile_probability::even ());
352 /* Get the probability that each jump below is true. */
353 op0_prob = op0_prob.invert ();
354 op1_prob = op1_prob.invert ();
356 if (if_false_label == NULL)
358 drop_through_label = gen_label_rtx ();
359 do_jump (op0, drop_through_label, NULL, op0_prob);
360 do_jump (op1, NULL, if_true_label, op1_prob);
362 else
364 do_jump (op0, if_false_label, NULL, op0_prob);
365 do_jump (op1, if_false_label, if_true_label, op1_prob);
367 break;
370 case TRUTH_ORIF_EXPR:
372 /* Spread the probability evenly between the two conditions. So
373 the first condition has half the total probability of being true.
374 The second condition has the other half of the total probability,
375 so its jump has a probability of half the total, relative to
376 the probability we reached it (i.e. the first condition was false). */
377 profile_probability op0_prob = profile_probability::uninitialized ();
378 profile_probability op1_prob = profile_probability::uninitialized ();
379 if (prob.initialized_p ())
381 op1_prob = prob;
382 op0_prob = op1_prob.split (profile_probability::even ());
384 if (if_true_label == NULL)
386 drop_through_label = gen_label_rtx ();
387 do_jump (op0, NULL, drop_through_label, op0_prob);
388 do_jump (op1, if_false_label, NULL, op1_prob);
390 else
392 do_jump (op0, NULL, if_true_label, op0_prob);
393 do_jump (op1, if_false_label, if_true_label, op1_prob);
395 break;
398 default:
399 gcc_unreachable ();
402 if (drop_through_label)
404 do_pending_stack_adjust ();
405 emit_label (drop_through_label);
409 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
410 the result is zero, or IF_TRUE_LABEL if the result is one.
411 Either of IF_FALSE_LABEL and IF_TRUE_LABEL may be zero,
412 meaning fall through in that case.
414 do_jump always does any pending stack adjust except when it does not
415 actually perform a jump. An example where there is no jump
416 is when EXP is `(foo (), 0)' and IF_FALSE_LABEL is null.
418 PROB is probability of jump to if_true_label. */
420 void
421 do_jump (tree exp, rtx_code_label *if_false_label,
422 rtx_code_label *if_true_label, profile_probability prob)
424 enum tree_code code = TREE_CODE (exp);
425 rtx temp;
426 int i;
427 tree type;
428 scalar_int_mode mode;
429 rtx_code_label *drop_through_label = NULL;
431 switch (code)
433 case ERROR_MARK:
434 break;
436 case INTEGER_CST:
438 rtx_code_label *lab = integer_zerop (exp) ? if_false_label
439 : if_true_label;
440 if (lab)
441 emit_jump (lab);
442 break;
445 #if 0
446 /* This is not true with #pragma weak */
447 case ADDR_EXPR:
448 /* The address of something can never be zero. */
449 if (if_true_label)
450 emit_jump (if_true_label);
451 break;
452 #endif
454 case NOP_EXPR:
455 if (TREE_CODE (TREE_OPERAND (exp, 0)) == COMPONENT_REF
456 || TREE_CODE (TREE_OPERAND (exp, 0)) == BIT_FIELD_REF
457 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_REF
458 || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_RANGE_REF)
459 goto normal;
460 /* FALLTHRU */
461 case CONVERT_EXPR:
462 /* If we are narrowing the operand, we have to do the compare in the
463 narrower mode. */
464 if ((TYPE_PRECISION (TREE_TYPE (exp))
465 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0)))))
466 goto normal;
467 /* FALLTHRU */
468 case NON_LVALUE_EXPR:
469 case ABS_EXPR:
470 case ABSU_EXPR:
471 case NEGATE_EXPR:
472 case LROTATE_EXPR:
473 case RROTATE_EXPR:
474 /* These cannot change zero->nonzero or vice versa. */
475 do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label, prob);
476 break;
478 case TRUTH_NOT_EXPR:
479 do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label,
480 prob.invert ());
481 break;
483 case COND_EXPR:
485 rtx_code_label *label1 = gen_label_rtx ();
486 if (!if_true_label || !if_false_label)
488 drop_through_label = gen_label_rtx ();
489 if (!if_true_label)
490 if_true_label = drop_through_label;
491 if (!if_false_label)
492 if_false_label = drop_through_label;
495 do_pending_stack_adjust ();
496 do_jump (TREE_OPERAND (exp, 0), label1, NULL,
497 profile_probability::uninitialized ());
498 do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label, prob);
499 emit_label (label1);
500 do_jump (TREE_OPERAND (exp, 2), if_false_label, if_true_label, prob);
501 break;
504 case COMPOUND_EXPR:
505 /* Lowered by gimplify.c. */
506 gcc_unreachable ();
508 case MINUS_EXPR:
509 /* Nonzero iff operands of minus differ. */
510 code = NE_EXPR;
512 /* FALLTHRU */
513 case EQ_EXPR:
514 case NE_EXPR:
515 case LT_EXPR:
516 case LE_EXPR:
517 case GT_EXPR:
518 case GE_EXPR:
519 case ORDERED_EXPR:
520 case UNORDERED_EXPR:
521 case UNLT_EXPR:
522 case UNLE_EXPR:
523 case UNGT_EXPR:
524 case UNGE_EXPR:
525 case UNEQ_EXPR:
526 case LTGT_EXPR:
527 case TRUTH_ANDIF_EXPR:
528 case TRUTH_ORIF_EXPR:
529 other_code:
530 do_jump_1 (code, TREE_OPERAND (exp, 0), TREE_OPERAND (exp, 1),
531 if_false_label, if_true_label, prob);
532 break;
534 case BIT_AND_EXPR:
535 /* fold_single_bit_test() converts (X & (1 << C)) into (X >> C) & 1.
536 See if the former is preferred for jump tests and restore it
537 if so. */
538 if (integer_onep (TREE_OPERAND (exp, 1)))
540 tree exp0 = TREE_OPERAND (exp, 0);
541 rtx_code_label *set_label, *clr_label;
542 profile_probability setclr_prob = prob;
544 /* Strip narrowing integral type conversions. */
545 while (CONVERT_EXPR_P (exp0)
546 && TREE_OPERAND (exp0, 0) != error_mark_node
547 && TYPE_PRECISION (TREE_TYPE (exp0))
548 <= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp0, 0))))
549 exp0 = TREE_OPERAND (exp0, 0);
551 /* "exp0 ^ 1" inverts the sense of the single bit test. */
552 if (TREE_CODE (exp0) == BIT_XOR_EXPR
553 && integer_onep (TREE_OPERAND (exp0, 1)))
555 exp0 = TREE_OPERAND (exp0, 0);
556 clr_label = if_true_label;
557 set_label = if_false_label;
558 setclr_prob = prob.invert ();
560 else
562 clr_label = if_false_label;
563 set_label = if_true_label;
566 if (TREE_CODE (exp0) == RSHIFT_EXPR)
568 tree arg = TREE_OPERAND (exp0, 0);
569 tree shift = TREE_OPERAND (exp0, 1);
570 tree argtype = TREE_TYPE (arg);
571 if (TREE_CODE (shift) == INTEGER_CST
572 && compare_tree_int (shift, 0) >= 0
573 && compare_tree_int (shift, HOST_BITS_PER_WIDE_INT) < 0
574 && prefer_and_bit_test (SCALAR_INT_TYPE_MODE (argtype),
575 TREE_INT_CST_LOW (shift)))
577 unsigned HOST_WIDE_INT mask
578 = HOST_WIDE_INT_1U << TREE_INT_CST_LOW (shift);
579 do_jump (build2 (BIT_AND_EXPR, argtype, arg,
580 build_int_cstu (argtype, mask)),
581 clr_label, set_label, setclr_prob);
582 break;
587 /* If we are AND'ing with a small constant, do this comparison in the
588 smallest type that fits. If the machine doesn't have comparisons
589 that small, it will be converted back to the wider comparison.
590 This helps if we are testing the sign bit of a narrower object.
591 combine can't do this for us because it can't know whether a
592 ZERO_EXTRACT or a compare in a smaller mode exists, but we do. */
594 if (! SLOW_BYTE_ACCESS
595 && TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST
596 && TYPE_PRECISION (TREE_TYPE (exp)) <= HOST_BITS_PER_WIDE_INT
597 && (i = tree_floor_log2 (TREE_OPERAND (exp, 1))) >= 0
598 && int_mode_for_size (i + 1, 0).exists (&mode)
599 && (type = lang_hooks.types.type_for_mode (mode, 1)) != 0
600 && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp))
601 && have_insn_for (COMPARE, TYPE_MODE (type)))
603 do_jump (fold_convert (type, exp), if_false_label, if_true_label,
604 prob);
605 break;
608 if (TYPE_PRECISION (TREE_TYPE (exp)) > 1
609 || TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST)
610 goto normal;
612 /* Boolean comparisons can be compiled as TRUTH_AND_EXPR. */
613 /* FALLTHRU */
615 case TRUTH_AND_EXPR:
616 /* High branch cost, expand as the bitwise AND of the conditions.
617 Do the same if the RHS has side effects, because we're effectively
618 turning a TRUTH_AND_EXPR into a TRUTH_ANDIF_EXPR. */
619 if (BRANCH_COST (optimize_insn_for_speed_p (),
620 false) >= 4
621 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1)))
622 goto normal;
623 code = TRUTH_ANDIF_EXPR;
624 goto other_code;
626 case BIT_IOR_EXPR:
627 case TRUTH_OR_EXPR:
628 /* High branch cost, expand as the bitwise OR of the conditions.
629 Do the same if the RHS has side effects, because we're effectively
630 turning a TRUTH_OR_EXPR into a TRUTH_ORIF_EXPR. */
631 if (BRANCH_COST (optimize_insn_for_speed_p (), false) >= 4
632 || TREE_SIDE_EFFECTS (TREE_OPERAND (exp, 1)))
633 goto normal;
634 code = TRUTH_ORIF_EXPR;
635 goto other_code;
637 /* Fall through and generate the normal code. */
638 default:
639 normal:
640 temp = expand_normal (exp);
641 do_pending_stack_adjust ();
642 /* The RTL optimizers prefer comparisons against pseudos. */
643 if (GET_CODE (temp) == SUBREG)
645 /* Compare promoted variables in their promoted mode. */
646 if (SUBREG_PROMOTED_VAR_P (temp)
647 && REG_P (XEXP (temp, 0)))
648 temp = XEXP (temp, 0);
649 else
650 temp = copy_to_reg (temp);
652 do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)),
653 NE, TYPE_UNSIGNED (TREE_TYPE (exp)),
654 GET_MODE (temp), NULL_RTX,
655 if_false_label, if_true_label, prob);
658 if (drop_through_label)
660 do_pending_stack_adjust ();
661 emit_label (drop_through_label);
665 /* Compare OP0 with OP1, word at a time, in mode MODE.
666 UNSIGNEDP says to do unsigned comparison.
667 Jump to IF_TRUE_LABEL if OP0 is greater, IF_FALSE_LABEL otherwise. */
669 static void
670 do_jump_by_parts_greater_rtx (scalar_int_mode mode, int unsignedp, rtx op0,
671 rtx op1, rtx_code_label *if_false_label,
672 rtx_code_label *if_true_label,
673 profile_probability prob)
675 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
676 rtx_code_label *drop_through_label = 0;
677 bool drop_through_if_true = false, drop_through_if_false = false;
678 enum rtx_code code = GT;
679 int i;
681 if (! if_true_label || ! if_false_label)
682 drop_through_label = gen_label_rtx ();
683 if (! if_true_label)
685 if_true_label = drop_through_label;
686 drop_through_if_true = true;
688 if (! if_false_label)
690 if_false_label = drop_through_label;
691 drop_through_if_false = true;
694 /* Deal with the special case 0 > x: only one comparison is necessary and
695 we reverse it to avoid jumping to the drop-through label. */
696 if (op0 == const0_rtx && drop_through_if_true && !drop_through_if_false)
698 code = LE;
699 if_true_label = if_false_label;
700 if_false_label = drop_through_label;
701 drop_through_if_true = false;
702 drop_through_if_false = true;
703 prob = prob.invert ();
706 /* Compare a word at a time, high order first. */
707 for (i = 0; i < nwords; i++)
709 rtx op0_word, op1_word;
711 if (WORDS_BIG_ENDIAN)
713 op0_word = operand_subword_force (op0, i, mode);
714 op1_word = operand_subword_force (op1, i, mode);
716 else
718 op0_word = operand_subword_force (op0, nwords - 1 - i, mode);
719 op1_word = operand_subword_force (op1, nwords - 1 - i, mode);
722 /* All but high-order word must be compared as unsigned. */
723 do_compare_rtx_and_jump (op0_word, op1_word, code, (unsignedp || i > 0),
724 word_mode, NULL_RTX, NULL, if_true_label,
725 prob);
727 /* Emit only one comparison for 0. Do not emit the last cond jump. */
728 if (op0 == const0_rtx || i == nwords - 1)
729 break;
731 /* Consider lower words only if these are equal. */
732 do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode,
733 NULL_RTX, NULL, if_false_label,
734 prob.invert ());
737 if (!drop_through_if_false)
738 emit_jump (if_false_label);
739 if (drop_through_label)
740 emit_label (drop_through_label);
743 /* Given a comparison expression EXP for values too wide to be compared
744 with one insn, test the comparison and jump to the appropriate label.
745 The code of EXP is ignored; we always test GT if SWAP is 0,
746 and LT if SWAP is 1. MODE is the mode of the two operands. */
748 static void
749 do_jump_by_parts_greater (scalar_int_mode mode, tree treeop0, tree treeop1,
750 int swap, rtx_code_label *if_false_label,
751 rtx_code_label *if_true_label,
752 profile_probability prob)
754 rtx op0 = expand_normal (swap ? treeop1 : treeop0);
755 rtx op1 = expand_normal (swap ? treeop0 : treeop1);
756 int unsignedp = TYPE_UNSIGNED (TREE_TYPE (treeop0));
758 do_jump_by_parts_greater_rtx (mode, unsignedp, op0, op1, if_false_label,
759 if_true_label, prob);
762 /* Jump according to whether OP0 is 0. We assume that OP0 has an integer
763 mode, MODE, that is too wide for the available compare insns. Either
764 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL
765 to indicate drop through. */
767 static void
768 do_jump_by_parts_zero_rtx (scalar_int_mode mode, rtx op0,
769 rtx_code_label *if_false_label,
770 rtx_code_label *if_true_label,
771 profile_probability prob)
773 int nwords = GET_MODE_SIZE (mode) / UNITS_PER_WORD;
774 rtx part;
775 int i;
776 rtx_code_label *drop_through_label = NULL;
778 /* The fastest way of doing this comparison on almost any machine is to
779 "or" all the words and compare the result. If all have to be loaded
780 from memory and this is a very wide item, it's possible this may
781 be slower, but that's highly unlikely. */
783 part = gen_reg_rtx (word_mode);
784 emit_move_insn (part, operand_subword_force (op0, 0, mode));
785 for (i = 1; i < nwords && part != 0; i++)
786 part = expand_binop (word_mode, ior_optab, part,
787 operand_subword_force (op0, i, mode),
788 part, 1, OPTAB_WIDEN);
790 if (part != 0)
792 do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode,
793 NULL_RTX, if_false_label, if_true_label, prob);
794 return;
797 /* If we couldn't do the "or" simply, do this with a series of compares. */
798 if (! if_false_label)
799 if_false_label = drop_through_label = gen_label_rtx ();
801 for (i = 0; i < nwords; i++)
802 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
803 const0_rtx, EQ, 1, word_mode, NULL_RTX,
804 if_false_label, NULL, prob);
806 if (if_true_label)
807 emit_jump (if_true_label);
809 if (drop_through_label)
810 emit_label (drop_through_label);
813 /* Test for the equality of two RTX expressions OP0 and OP1 in mode MODE,
814 where MODE is an integer mode too wide to be compared with one insn.
815 Either (but not both) of IF_TRUE_LABEL and IF_FALSE_LABEL may be NULL_RTX
816 to indicate drop through. */
818 static void
819 do_jump_by_parts_equality_rtx (scalar_int_mode mode, rtx op0, rtx op1,
820 rtx_code_label *if_false_label,
821 rtx_code_label *if_true_label,
822 profile_probability prob)
824 int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
825 rtx_code_label *drop_through_label = NULL;
826 int i;
828 if (op1 == const0_rtx)
830 do_jump_by_parts_zero_rtx (mode, op0, if_false_label, if_true_label,
831 prob);
832 return;
834 else if (op0 == const0_rtx)
836 do_jump_by_parts_zero_rtx (mode, op1, if_false_label, if_true_label,
837 prob);
838 return;
841 if (! if_false_label)
842 drop_through_label = if_false_label = gen_label_rtx ();
844 for (i = 0; i < nwords; i++)
845 do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
846 operand_subword_force (op1, i, mode),
847 EQ, 0, word_mode, NULL_RTX,
848 if_false_label, NULL, prob);
850 if (if_true_label)
851 emit_jump (if_true_label);
852 if (drop_through_label)
853 emit_label (drop_through_label);
856 /* Given an EQ_EXPR expression EXP for values too wide to be compared
857 with one insn, test the comparison and jump to the appropriate label.
858 MODE is the mode of the two operands. */
860 static void
861 do_jump_by_parts_equality (scalar_int_mode mode, tree treeop0, tree treeop1,
862 rtx_code_label *if_false_label,
863 rtx_code_label *if_true_label,
864 profile_probability prob)
866 rtx op0 = expand_normal (treeop0);
867 rtx op1 = expand_normal (treeop1);
868 do_jump_by_parts_equality_rtx (mode, op0, op1, if_false_label,
869 if_true_label, prob);
872 /* Split a comparison into two others, the second of which has the other
873 "orderedness". The first is always ORDERED or UNORDERED if MODE
874 does not honor NaNs (which means that it can be skipped in that case;
875 see do_compare_rtx_and_jump).
877 The two conditions are written in *CODE1 and *CODE2. Return true if
878 the conditions must be ANDed, false if they must be ORed. */
880 bool
881 split_comparison (enum rtx_code code, machine_mode mode,
882 enum rtx_code *code1, enum rtx_code *code2)
884 switch (code)
886 case LT:
887 *code1 = ORDERED;
888 *code2 = UNLT;
889 return true;
890 case LE:
891 *code1 = ORDERED;
892 *code2 = UNLE;
893 return true;
894 case GT:
895 *code1 = ORDERED;
896 *code2 = UNGT;
897 return true;
898 case GE:
899 *code1 = ORDERED;
900 *code2 = UNGE;
901 return true;
902 case EQ:
903 *code1 = ORDERED;
904 *code2 = UNEQ;
905 return true;
906 case NE:
907 *code1 = UNORDERED;
908 *code2 = LTGT;
909 return false;
910 case UNLT:
911 *code1 = UNORDERED;
912 *code2 = LT;
913 return false;
914 case UNLE:
915 *code1 = UNORDERED;
916 *code2 = LE;
917 return false;
918 case UNGT:
919 *code1 = UNORDERED;
920 *code2 = GT;
921 return false;
922 case UNGE:
923 *code1 = UNORDERED;
924 *code2 = GE;
925 return false;
926 case UNEQ:
927 *code1 = UNORDERED;
928 *code2 = EQ;
929 return false;
930 case LTGT:
931 /* Do not turn a trapping comparison into a non-trapping one. */
932 if (HONOR_SNANS (mode))
934 *code1 = LT;
935 *code2 = GT;
936 return false;
938 else
940 *code1 = ORDERED;
941 *code2 = NE;
942 return true;
944 default:
945 gcc_unreachable ();
950 /* Like do_compare_and_jump but expects the values to compare as two rtx's.
951 The decision as to signed or unsigned comparison must be made by the caller.
953 If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
954 compared. */
956 void
957 do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
958 machine_mode mode, rtx size,
959 rtx_code_label *if_false_label,
960 rtx_code_label *if_true_label,
961 profile_probability prob)
963 rtx tem;
964 rtx_code_label *dummy_label = NULL;
966 /* Reverse the comparison if that is safe and we want to jump if it is
967 false. Also convert to the reverse comparison if the target can
968 implement it. */
969 if ((! if_true_label
970 || ! can_compare_p (code, mode, ccp_jump))
971 && (! FLOAT_MODE_P (mode)
972 || code == ORDERED || code == UNORDERED
973 || (! HONOR_NANS (mode) && (code == LTGT || code == UNEQ))
974 || (! HONOR_SNANS (mode) && (code == EQ || code == NE))))
976 enum rtx_code rcode;
977 if (FLOAT_MODE_P (mode))
978 rcode = reverse_condition_maybe_unordered (code);
979 else
980 rcode = reverse_condition (code);
982 /* Canonicalize to UNORDERED for the libcall. */
983 if (can_compare_p (rcode, mode, ccp_jump)
984 || (code == ORDERED && ! can_compare_p (ORDERED, mode, ccp_jump)))
986 std::swap (if_true_label, if_false_label);
987 code = rcode;
988 prob = prob.invert ();
992 /* If one operand is constant, make it the second one. Only do this
993 if the other operand is not constant as well. */
995 if (swap_commutative_operands_p (op0, op1))
997 std::swap (op0, op1);
998 code = swap_condition (code);
1001 do_pending_stack_adjust ();
1003 code = unsignedp ? unsigned_condition (code) : code;
1004 if ((tem = simplify_relational_operation (code, mode, VOIDmode,
1005 op0, op1)) != 0)
1007 if (CONSTANT_P (tem))
1009 rtx_code_label *label = (tem == const0_rtx
1010 || tem == CONST0_RTX (mode))
1011 ? if_false_label : if_true_label;
1012 if (label)
1013 emit_jump (label);
1014 return;
1017 code = GET_CODE (tem);
1018 mode = GET_MODE (tem);
1019 op0 = XEXP (tem, 0);
1020 op1 = XEXP (tem, 1);
1021 unsignedp = (code == GTU || code == LTU || code == GEU || code == LEU);
1024 if (! if_true_label)
1025 dummy_label = if_true_label = gen_label_rtx ();
1027 scalar_int_mode int_mode;
1028 if (is_int_mode (mode, &int_mode)
1029 && ! can_compare_p (code, int_mode, ccp_jump))
1031 switch (code)
1033 case LTU:
1034 do_jump_by_parts_greater_rtx (int_mode, 1, op1, op0,
1035 if_false_label, if_true_label, prob);
1036 break;
1038 case LEU:
1039 do_jump_by_parts_greater_rtx (int_mode, 1, op0, op1,
1040 if_true_label, if_false_label,
1041 prob.invert ());
1042 break;
1044 case GTU:
1045 do_jump_by_parts_greater_rtx (int_mode, 1, op0, op1,
1046 if_false_label, if_true_label, prob);
1047 break;
1049 case GEU:
1050 do_jump_by_parts_greater_rtx (int_mode, 1, op1, op0,
1051 if_true_label, if_false_label,
1052 prob.invert ());
1053 break;
1055 case LT:
1056 do_jump_by_parts_greater_rtx (int_mode, 0, op1, op0,
1057 if_false_label, if_true_label, prob);
1058 break;
1060 case LE:
1061 do_jump_by_parts_greater_rtx (int_mode, 0, op0, op1,
1062 if_true_label, if_false_label,
1063 prob.invert ());
1064 break;
1066 case GT:
1067 do_jump_by_parts_greater_rtx (int_mode, 0, op0, op1,
1068 if_false_label, if_true_label, prob);
1069 break;
1071 case GE:
1072 do_jump_by_parts_greater_rtx (int_mode, 0, op1, op0,
1073 if_true_label, if_false_label,
1074 prob.invert ());
1075 break;
1077 case EQ:
1078 do_jump_by_parts_equality_rtx (int_mode, op0, op1, if_false_label,
1079 if_true_label, prob);
1080 break;
1082 case NE:
1083 do_jump_by_parts_equality_rtx (int_mode, op0, op1, if_true_label,
1084 if_false_label,
1085 prob.invert ());
1086 break;
1088 default:
1089 gcc_unreachable ();
1092 else
1094 if (SCALAR_FLOAT_MODE_P (mode)
1095 && ! can_compare_p (code, mode, ccp_jump)
1096 && can_compare_p (swap_condition (code), mode, ccp_jump))
1098 code = swap_condition (code);
1099 std::swap (op0, op1);
1101 else if (SCALAR_FLOAT_MODE_P (mode)
1102 && ! can_compare_p (code, mode, ccp_jump)
1103 /* Never split ORDERED and UNORDERED.
1104 These must be implemented. */
1105 && (code != ORDERED && code != UNORDERED)
1106 /* Split a floating-point comparison if
1107 we can jump on other conditions... */
1108 && (have_insn_for (COMPARE, mode)
1109 /* ... or if there is no libcall for it. */
1110 || code_to_optab (code) == unknown_optab))
1112 enum rtx_code first_code;
1113 bool and_them = split_comparison (code, mode, &first_code, &code);
1115 /* If there are no NaNs, the first comparison should always fall
1116 through. */
1117 if (!HONOR_NANS (mode))
1118 gcc_assert (first_code == (and_them ? ORDERED : UNORDERED));
1120 else
1122 profile_probability cprob
1123 = profile_probability::guessed_always ();
1124 if (first_code == UNORDERED)
1125 cprob = cprob.apply_scale (1, 100);
1126 else if (first_code == ORDERED)
1127 cprob = cprob.apply_scale (99, 100);
1128 else
1129 cprob = profile_probability::even ();
1130 /* We want to split:
1131 if (x) goto t; // prob;
1132 into
1133 if (a) goto t; // first_prob;
1134 if (b) goto t; // prob;
1135 such that the overall probability of jumping to t
1136 remains the same and first_prob is prob * cprob. */
1137 if (and_them)
1139 rtx_code_label *dest_label;
1140 prob = prob.invert ();
1141 profile_probability first_prob = prob.split (cprob).invert ();
1142 prob = prob.invert ();
1143 /* If we only jump if true, just bypass the second jump. */
1144 if (! if_false_label)
1146 if (! dummy_label)
1147 dummy_label = gen_label_rtx ();
1148 dest_label = dummy_label;
1150 else
1151 dest_label = if_false_label;
1152 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
1153 size, dest_label, NULL, first_prob);
1155 else
1157 profile_probability first_prob = prob.split (cprob);
1158 do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode,
1159 size, NULL, if_true_label, first_prob);
1164 emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp,
1165 if_true_label, prob);
1168 if (if_false_label)
1169 emit_jump (if_false_label);
1170 if (dummy_label)
1171 emit_label (dummy_label);
1174 /* Generate code for a comparison expression EXP (including code to compute
1175 the values to be compared) and a conditional jump to IF_FALSE_LABEL and/or
1176 IF_TRUE_LABEL. One of the labels can be NULL_RTX, in which case the
1177 generated code will drop through.
1178 SIGNED_CODE should be the rtx operation for this comparison for
1179 signed data; UNSIGNED_CODE, likewise for use if data is unsigned.
1181 We force a stack adjustment unless there are currently
1182 things pushed on the stack that aren't yet used. */
1184 static void
1185 do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
1186 enum rtx_code unsigned_code,
1187 rtx_code_label *if_false_label,
1188 rtx_code_label *if_true_label, profile_probability prob)
1190 rtx op0, op1;
1191 tree type;
1192 machine_mode mode;
1193 int unsignedp;
1194 enum rtx_code code;
1196 /* Don't crash if the comparison was erroneous. */
1197 op0 = expand_normal (treeop0);
1198 if (TREE_CODE (treeop0) == ERROR_MARK)
1199 return;
1201 op1 = expand_normal (treeop1);
1202 if (TREE_CODE (treeop1) == ERROR_MARK)
1203 return;
1205 type = TREE_TYPE (treeop0);
1206 if (TREE_CODE (treeop0) == INTEGER_CST
1207 && (TREE_CODE (treeop1) != INTEGER_CST
1208 || (GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (type))
1209 > GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (TREE_TYPE (treeop1))))))
1210 /* op0 might have been replaced by promoted constant, in which
1211 case the type of second argument should be used. */
1212 type = TREE_TYPE (treeop1);
1213 mode = TYPE_MODE (type);
1214 unsignedp = TYPE_UNSIGNED (type);
1215 code = unsignedp ? unsigned_code : signed_code;
1217 /* If function pointers need to be "canonicalized" before they can
1218 be reliably compared, then canonicalize them.
1219 Only do this if *both* sides of the comparison are function pointers.
1220 If one side isn't, we want a noncanonicalized comparison. See PR
1221 middle-end/17564. */
1222 if (targetm.have_canonicalize_funcptr_for_compare ()
1223 && POINTER_TYPE_P (TREE_TYPE (treeop0))
1224 && POINTER_TYPE_P (TREE_TYPE (treeop1))
1225 && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop0)))
1226 && FUNC_OR_METHOD_TYPE_P (TREE_TYPE (TREE_TYPE (treeop1))))
1228 rtx new_op0 = gen_reg_rtx (mode);
1229 rtx new_op1 = gen_reg_rtx (mode);
1231 emit_insn (targetm.gen_canonicalize_funcptr_for_compare (new_op0, op0));
1232 op0 = new_op0;
1234 emit_insn (targetm.gen_canonicalize_funcptr_for_compare (new_op1, op1));
1235 op1 = new_op1;
1238 do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode,
1239 ((mode == BLKmode)
1240 ? expr_size (treeop0) : NULL_RTX),
1241 if_false_label, if_true_label, prob);
1244 #include "gt-dojump.h"