1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2002,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /*@@ This file should be rewritten to use an arbitrary precision
23 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
24 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
25 @@ The routines that translate from the ap rep should
26 @@ warn if precision et. al. is lost.
27 @@ This would also make life easier when this technology is used
28 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type takes a constant and prior overflow indicator, and
43 forces the value to fit the type. It returns an overflow indicator. */
47 #include "coretypes.h"
58 #include "langhooks.h"
60 static void encode PARAMS ((HOST_WIDE_INT *,
61 unsigned HOST_WIDE_INT,
63 static void decode PARAMS ((HOST_WIDE_INT *,
64 unsigned HOST_WIDE_INT *,
66 static tree negate_expr PARAMS ((tree));
67 static tree split_tree PARAMS ((tree, enum tree_code, tree *, tree *,
69 static tree associate_trees PARAMS ((tree, tree, enum tree_code, tree));
70 static tree int_const_binop PARAMS ((enum tree_code, tree, tree, int));
71 static tree const_binop PARAMS ((enum tree_code, tree, tree, int));
72 static hashval_t size_htab_hash PARAMS ((const void *));
73 static int size_htab_eq PARAMS ((const void *, const void *));
74 static tree fold_convert PARAMS ((tree, tree));
75 static enum tree_code invert_tree_comparison PARAMS ((enum tree_code));
76 static enum tree_code swap_tree_comparison PARAMS ((enum tree_code));
77 static int comparison_to_compcode PARAMS ((enum tree_code));
78 static enum tree_code compcode_to_comparison PARAMS ((int));
79 static int truth_value_p PARAMS ((enum tree_code));
80 static int operand_equal_for_comparison_p PARAMS ((tree, tree, tree));
81 static int twoval_comparison_p PARAMS ((tree, tree *, tree *, int *));
82 static tree eval_subst PARAMS ((tree, tree, tree, tree, tree));
83 static tree omit_one_operand PARAMS ((tree, tree, tree));
84 static tree pedantic_omit_one_operand PARAMS ((tree, tree, tree));
85 static tree distribute_bit_expr PARAMS ((enum tree_code, tree, tree, tree));
86 static tree make_bit_field_ref PARAMS ((tree, tree, int, int, int));
87 static tree optimize_bit_field_compare PARAMS ((enum tree_code, tree,
89 static tree decode_field_reference PARAMS ((tree, HOST_WIDE_INT *,
91 enum machine_mode *, int *,
92 int *, tree *, tree *));
93 static int all_ones_mask_p PARAMS ((tree, int));
94 static tree sign_bit_p PARAMS ((tree, tree));
95 static int simple_operand_p PARAMS ((tree));
96 static tree range_binop PARAMS ((enum tree_code, tree, tree, int,
98 static tree make_range PARAMS ((tree, int *, tree *, tree *));
99 static tree build_range_check PARAMS ((tree, tree, int, tree, tree));
100 static int merge_ranges PARAMS ((int *, tree *, tree *, int, tree, tree,
102 static tree fold_range_test PARAMS ((tree));
103 static tree unextend PARAMS ((tree, int, int, tree));
104 static tree fold_truthop PARAMS ((enum tree_code, tree, tree, tree));
105 static tree optimize_minmax_comparison PARAMS ((tree));
106 static tree extract_muldiv PARAMS ((tree, tree, enum tree_code, tree));
107 static tree extract_muldiv_1 PARAMS ((tree, tree, enum tree_code, tree));
108 static tree strip_compound_expr PARAMS ((tree, tree));
109 static int multiple_of_p PARAMS ((tree, tree, tree));
110 static tree constant_boolean_node PARAMS ((int, tree));
111 static int count_cond PARAMS ((tree, int));
112 static tree fold_binary_op_with_conditional_arg
113 PARAMS ((enum tree_code, tree, tree, tree, int));
114 static bool fold_real_zero_addition_p PARAMS ((tree, tree, int));
116 /* The following constants represent a bit based encoding of GCC's
117 comparison operators. This encoding simplifies transformations
118 on relational comparison operators, such as AND and OR. */
119 #define COMPCODE_FALSE 0
120 #define COMPCODE_LT 1
121 #define COMPCODE_EQ 2
122 #define COMPCODE_LE 3
123 #define COMPCODE_GT 4
124 #define COMPCODE_NE 5
125 #define COMPCODE_GE 6
126 #define COMPCODE_TRUE 7
128 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
129 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
130 and SUM1. Then this yields nonzero if overflow occurred during the
133 Overflow occurs if A and B have the same sign, but A and SUM differ in
134 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
136 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
138 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
139 We do that by representing the two-word integer in 4 words, with only
140 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
141 number. The value of the word is LOWPART + HIGHPART * BASE. */
144 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
145 #define HIGHPART(x) \
146 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
147 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
149 /* Unpack a two-word integer into 4 words.
150 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
151 WORDS points to the array of HOST_WIDE_INTs. */
154 encode (words, low, hi)
155 HOST_WIDE_INT *words;
156 unsigned HOST_WIDE_INT low;
159 words[0] = LOWPART (low);
160 words[1] = HIGHPART (low);
161 words[2] = LOWPART (hi);
162 words[3] = HIGHPART (hi);
165 /* Pack an array of 4 words into a two-word integer.
166 WORDS points to the array of words.
167 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
170 decode (words, low, hi)
171 HOST_WIDE_INT *words;
172 unsigned HOST_WIDE_INT *low;
175 *low = words[0] + words[1] * BASE;
176 *hi = words[2] + words[3] * BASE;
179 /* Make the integer constant T valid for its type by setting to 0 or 1 all
180 the bits in the constant that don't belong in the type.
182 Return 1 if a signed overflow occurs, 0 otherwise. If OVERFLOW is
183 nonzero, a signed overflow has already occurred in calculating T, so
187 force_fit_type (t, overflow)
191 unsigned HOST_WIDE_INT low;
195 if (TREE_CODE (t) == REAL_CST)
197 /* ??? Used to check for overflow here via CHECK_FLOAT_TYPE.
198 Consider doing it via real_convert now. */
202 else if (TREE_CODE (t) != INTEGER_CST)
205 low = TREE_INT_CST_LOW (t);
206 high = TREE_INT_CST_HIGH (t);
208 if (POINTER_TYPE_P (TREE_TYPE (t)))
211 prec = TYPE_PRECISION (TREE_TYPE (t));
213 /* First clear all bits that are beyond the type's precision. */
215 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
217 else if (prec > HOST_BITS_PER_WIDE_INT)
218 TREE_INT_CST_HIGH (t)
219 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
222 TREE_INT_CST_HIGH (t) = 0;
223 if (prec < HOST_BITS_PER_WIDE_INT)
224 TREE_INT_CST_LOW (t) &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
227 /* Unsigned types do not suffer sign extension or overflow unless they
229 if (TREE_UNSIGNED (TREE_TYPE (t))
230 && ! (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
231 && TYPE_IS_SIZETYPE (TREE_TYPE (t))))
234 /* If the value's sign bit is set, extend the sign. */
235 if (prec != 2 * HOST_BITS_PER_WIDE_INT
236 && (prec > HOST_BITS_PER_WIDE_INT
237 ? 0 != (TREE_INT_CST_HIGH (t)
239 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
240 : 0 != (TREE_INT_CST_LOW (t)
241 & ((unsigned HOST_WIDE_INT) 1 << (prec - 1)))))
243 /* Value is negative:
244 set to 1 all the bits that are outside this type's precision. */
245 if (prec > HOST_BITS_PER_WIDE_INT)
246 TREE_INT_CST_HIGH (t)
247 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
250 TREE_INT_CST_HIGH (t) = -1;
251 if (prec < HOST_BITS_PER_WIDE_INT)
252 TREE_INT_CST_LOW (t) |= ((unsigned HOST_WIDE_INT) (-1) << prec);
256 /* Return nonzero if signed overflow occurred. */
258 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
262 /* Add two doubleword integers with doubleword result.
263 Each argument is given as two `HOST_WIDE_INT' pieces.
264 One argument is L1 and H1; the other, L2 and H2.
265 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
268 add_double (l1, h1, l2, h2, lv, hv)
269 unsigned HOST_WIDE_INT l1, l2;
270 HOST_WIDE_INT h1, h2;
271 unsigned HOST_WIDE_INT *lv;
274 unsigned HOST_WIDE_INT l;
278 h = h1 + h2 + (l < l1);
282 return OVERFLOW_SUM_SIGN (h1, h2, h);
285 /* Negate a doubleword integer with doubleword result.
286 Return nonzero if the operation overflows, assuming it's signed.
287 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
288 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
291 neg_double (l1, h1, lv, hv)
292 unsigned HOST_WIDE_INT l1;
294 unsigned HOST_WIDE_INT *lv;
301 return (*hv & h1) < 0;
311 /* Multiply two doubleword integers with doubleword result.
312 Return nonzero if the operation overflows, assuming it's signed.
313 Each argument is given as two `HOST_WIDE_INT' pieces.
314 One argument is L1 and H1; the other, L2 and H2.
315 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
318 mul_double (l1, h1, l2, h2, lv, hv)
319 unsigned HOST_WIDE_INT l1, l2;
320 HOST_WIDE_INT h1, h2;
321 unsigned HOST_WIDE_INT *lv;
324 HOST_WIDE_INT arg1[4];
325 HOST_WIDE_INT arg2[4];
326 HOST_WIDE_INT prod[4 * 2];
327 unsigned HOST_WIDE_INT carry;
329 unsigned HOST_WIDE_INT toplow, neglow;
330 HOST_WIDE_INT tophigh, neghigh;
332 encode (arg1, l1, h1);
333 encode (arg2, l2, h2);
335 memset ((char *) prod, 0, sizeof prod);
337 for (i = 0; i < 4; i++)
340 for (j = 0; j < 4; j++)
343 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
344 carry += arg1[i] * arg2[j];
345 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
347 prod[k] = LOWPART (carry);
348 carry = HIGHPART (carry);
353 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
355 /* Check for overflow by calculating the top half of the answer in full;
356 it should agree with the low half's sign bit. */
357 decode (prod + 4, &toplow, &tophigh);
360 neg_double (l2, h2, &neglow, &neghigh);
361 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
365 neg_double (l1, h1, &neglow, &neghigh);
366 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
368 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
371 /* Shift the doubleword integer in L1, H1 left by COUNT places
372 keeping only PREC bits of result.
373 Shift right if COUNT is negative.
374 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
375 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
378 lshift_double (l1, h1, count, prec, lv, hv, arith)
379 unsigned HOST_WIDE_INT l1;
380 HOST_WIDE_INT h1, count;
382 unsigned HOST_WIDE_INT *lv;
386 unsigned HOST_WIDE_INT signmask;
390 rshift_double (l1, h1, -count, prec, lv, hv, arith);
394 #ifdef SHIFT_COUNT_TRUNCATED
395 if (SHIFT_COUNT_TRUNCATED)
399 if (count >= 2 * HOST_BITS_PER_WIDE_INT)
401 /* Shifting by the host word size is undefined according to the
402 ANSI standard, so we must handle this as a special case. */
406 else if (count >= HOST_BITS_PER_WIDE_INT)
408 *hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
413 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
414 | (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
418 /* Sign extend all bits that are beyond the precision. */
420 signmask = -((prec > HOST_BITS_PER_WIDE_INT
421 ? ((unsigned HOST_WIDE_INT) *hv
422 >> (prec - HOST_BITS_PER_WIDE_INT - 1))
423 : (*lv >> (prec - 1))) & 1);
425 if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
427 else if (prec >= HOST_BITS_PER_WIDE_INT)
429 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
430 *hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT);
435 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
436 *lv |= signmask << prec;
440 /* Shift the doubleword integer in L1, H1 right by COUNT places
441 keeping only PREC bits of result. COUNT must be positive.
442 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
443 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
446 rshift_double (l1, h1, count, prec, lv, hv, arith)
447 unsigned HOST_WIDE_INT l1;
448 HOST_WIDE_INT h1, count;
450 unsigned HOST_WIDE_INT *lv;
454 unsigned HOST_WIDE_INT signmask;
457 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
460 #ifdef SHIFT_COUNT_TRUNCATED
461 if (SHIFT_COUNT_TRUNCATED)
465 if (count >= 2 * HOST_BITS_PER_WIDE_INT)
467 /* Shifting by the host word size is undefined according to the
468 ANSI standard, so we must handle this as a special case. */
472 else if (count >= HOST_BITS_PER_WIDE_INT)
475 *lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT);
479 *hv = (unsigned HOST_WIDE_INT) h1 >> count;
481 | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
484 /* Zero / sign extend all bits that are beyond the precision. */
486 if (count >= (HOST_WIDE_INT)prec)
491 else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT)
493 else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
495 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT));
496 *hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
501 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count));
502 *lv |= signmask << (prec - count);
506 /* Rotate the doubleword integer in L1, H1 left by COUNT places
507 keeping only PREC bits of result.
508 Rotate right if COUNT is negative.
509 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
512 lrotate_double (l1, h1, count, prec, lv, hv)
513 unsigned HOST_WIDE_INT l1;
514 HOST_WIDE_INT h1, count;
516 unsigned HOST_WIDE_INT *lv;
519 unsigned HOST_WIDE_INT s1l, s2l;
520 HOST_WIDE_INT s1h, s2h;
526 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
527 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
532 /* Rotate the doubleword integer in L1, H1 left by COUNT places
533 keeping only PREC bits of result. COUNT must be positive.
534 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
537 rrotate_double (l1, h1, count, prec, lv, hv)
538 unsigned HOST_WIDE_INT l1;
539 HOST_WIDE_INT h1, count;
541 unsigned HOST_WIDE_INT *lv;
544 unsigned HOST_WIDE_INT s1l, s2l;
545 HOST_WIDE_INT s1h, s2h;
551 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
552 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
557 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
558 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
559 CODE is a tree code for a kind of division, one of
560 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
562 It controls how the quotient is rounded to an integer.
563 Return nonzero if the operation overflows.
564 UNS nonzero says do unsigned division. */
567 div_and_round_double (code, uns,
568 lnum_orig, hnum_orig, lden_orig, hden_orig,
569 lquo, hquo, lrem, hrem)
572 unsigned HOST_WIDE_INT lnum_orig; /* num == numerator == dividend */
573 HOST_WIDE_INT hnum_orig;
574 unsigned HOST_WIDE_INT lden_orig; /* den == denominator == divisor */
575 HOST_WIDE_INT hden_orig;
576 unsigned HOST_WIDE_INT *lquo, *lrem;
577 HOST_WIDE_INT *hquo, *hrem;
580 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
581 HOST_WIDE_INT den[4], quo[4];
583 unsigned HOST_WIDE_INT work;
584 unsigned HOST_WIDE_INT carry = 0;
585 unsigned HOST_WIDE_INT lnum = lnum_orig;
586 HOST_WIDE_INT hnum = hnum_orig;
587 unsigned HOST_WIDE_INT lden = lden_orig;
588 HOST_WIDE_INT hden = hden_orig;
591 if (hden == 0 && lden == 0)
592 overflow = 1, lden = 1;
594 /* calculate quotient sign and convert operands to unsigned. */
600 /* (minimum integer) / (-1) is the only overflow case. */
601 if (neg_double (lnum, hnum, &lnum, &hnum)
602 && ((HOST_WIDE_INT) lden & hden) == -1)
608 neg_double (lden, hden, &lden, &hden);
612 if (hnum == 0 && hden == 0)
613 { /* single precision */
615 /* This unsigned division rounds toward zero. */
621 { /* trivial case: dividend < divisor */
622 /* hden != 0 already checked. */
629 memset ((char *) quo, 0, sizeof quo);
631 memset ((char *) num, 0, sizeof num); /* to zero 9th element */
632 memset ((char *) den, 0, sizeof den);
634 encode (num, lnum, hnum);
635 encode (den, lden, hden);
637 /* Special code for when the divisor < BASE. */
638 if (hden == 0 && lden < (unsigned HOST_WIDE_INT) BASE)
640 /* hnum != 0 already checked. */
641 for (i = 4 - 1; i >= 0; i--)
643 work = num[i] + carry * BASE;
644 quo[i] = work / lden;
650 /* Full double precision division,
651 with thanks to Don Knuth's "Seminumerical Algorithms". */
652 int num_hi_sig, den_hi_sig;
653 unsigned HOST_WIDE_INT quo_est, scale;
655 /* Find the highest nonzero divisor digit. */
656 for (i = 4 - 1;; i--)
663 /* Insure that the first digit of the divisor is at least BASE/2.
664 This is required by the quotient digit estimation algorithm. */
666 scale = BASE / (den[den_hi_sig] + 1);
668 { /* scale divisor and dividend */
670 for (i = 0; i <= 4 - 1; i++)
672 work = (num[i] * scale) + carry;
673 num[i] = LOWPART (work);
674 carry = HIGHPART (work);
679 for (i = 0; i <= 4 - 1; i++)
681 work = (den[i] * scale) + carry;
682 den[i] = LOWPART (work);
683 carry = HIGHPART (work);
684 if (den[i] != 0) den_hi_sig = i;
691 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--)
693 /* Guess the next quotient digit, quo_est, by dividing the first
694 two remaining dividend digits by the high order quotient digit.
695 quo_est is never low and is at most 2 high. */
696 unsigned HOST_WIDE_INT tmp;
698 num_hi_sig = i + den_hi_sig + 1;
699 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
700 if (num[num_hi_sig] != den[den_hi_sig])
701 quo_est = work / den[den_hi_sig];
705 /* Refine quo_est so it's usually correct, and at most one high. */
706 tmp = work - quo_est * den[den_hi_sig];
708 && (den[den_hi_sig - 1] * quo_est
709 > (tmp * BASE + num[num_hi_sig - 2])))
712 /* Try QUO_EST as the quotient digit, by multiplying the
713 divisor by QUO_EST and subtracting from the remaining dividend.
714 Keep in mind that QUO_EST is the I - 1st digit. */
717 for (j = 0; j <= den_hi_sig; j++)
719 work = quo_est * den[j] + carry;
720 carry = HIGHPART (work);
721 work = num[i + j] - LOWPART (work);
722 num[i + j] = LOWPART (work);
723 carry += HIGHPART (work) != 0;
726 /* If quo_est was high by one, then num[i] went negative and
727 we need to correct things. */
728 if (num[num_hi_sig] < (HOST_WIDE_INT) carry)
731 carry = 0; /* add divisor back in */
732 for (j = 0; j <= den_hi_sig; j++)
734 work = num[i + j] + den[j] + carry;
735 carry = HIGHPART (work);
736 num[i + j] = LOWPART (work);
739 num [num_hi_sig] += carry;
742 /* Store the quotient digit. */
747 decode (quo, lquo, hquo);
750 /* if result is negative, make it so. */
752 neg_double (*lquo, *hquo, lquo, hquo);
754 /* compute trial remainder: rem = num - (quo * den) */
755 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
756 neg_double (*lrem, *hrem, lrem, hrem);
757 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
762 case TRUNC_MOD_EXPR: /* round toward zero */
763 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
767 case FLOOR_MOD_EXPR: /* round toward negative infinity */
768 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
771 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
779 case CEIL_MOD_EXPR: /* round toward positive infinity */
780 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
782 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
790 case ROUND_MOD_EXPR: /* round to closest integer */
792 unsigned HOST_WIDE_INT labs_rem = *lrem;
793 HOST_WIDE_INT habs_rem = *hrem;
794 unsigned HOST_WIDE_INT labs_den = lden, ltwice;
795 HOST_WIDE_INT habs_den = hden, htwice;
797 /* Get absolute values */
799 neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
801 neg_double (lden, hden, &labs_den, &habs_den);
803 /* If (2 * abs (lrem) >= abs (lden)) */
804 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
805 labs_rem, habs_rem, <wice, &htwice);
807 if (((unsigned HOST_WIDE_INT) habs_den
808 < (unsigned HOST_WIDE_INT) htwice)
809 || (((unsigned HOST_WIDE_INT) habs_den
810 == (unsigned HOST_WIDE_INT) htwice)
811 && (labs_den < ltwice)))
815 add_double (*lquo, *hquo,
816 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
819 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
831 /* compute true remainder: rem = num - (quo * den) */
832 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
833 neg_double (*lrem, *hrem, lrem, hrem);
834 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
838 /* Given T, an expression, return the negation of T. Allow for T to be
839 null, in which case return null. */
851 type = TREE_TYPE (t);
854 switch (TREE_CODE (t))
858 if (! TREE_UNSIGNED (type)
859 && 0 != (tem = fold (build1 (NEGATE_EXPR, type, t)))
860 && ! TREE_OVERFLOW (tem))
865 return convert (type, TREE_OPERAND (t, 0));
868 /* - (A - B) -> B - A */
869 if (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
870 return convert (type,
871 fold (build (MINUS_EXPR, TREE_TYPE (t),
873 TREE_OPERAND (t, 0))));
880 return convert (type, fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t)));
883 /* Split a tree IN into a constant, literal and variable parts that could be
884 combined with CODE to make IN. "constant" means an expression with
885 TREE_CONSTANT but that isn't an actual constant. CODE must be a
886 commutative arithmetic operation. Store the constant part into *CONP,
887 the literal in *LITP and return the variable part. If a part isn't
888 present, set it to null. If the tree does not decompose in this way,
889 return the entire tree as the variable part and the other parts as null.
891 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
892 case, we negate an operand that was subtracted. Except if it is a
893 literal for which we use *MINUS_LITP instead.
895 If NEGATE_P is true, we are negating all of IN, again except a literal
896 for which we use *MINUS_LITP instead.
898 If IN is itself a literal or constant, return it as appropriate.
900 Note that we do not guarantee that any of the three values will be the
901 same type as IN, but they will have the same signedness and mode. */
904 split_tree (in, code, conp, litp, minus_litp, negate_p)
907 tree *conp, *litp, *minus_litp;
916 /* Strip any conversions that don't change the machine mode or signedness. */
917 STRIP_SIGN_NOPS (in);
919 if (TREE_CODE (in) == INTEGER_CST || TREE_CODE (in) == REAL_CST)
921 else if (TREE_CODE (in) == code
922 || (! FLOAT_TYPE_P (TREE_TYPE (in))
923 /* We can associate addition and subtraction together (even
924 though the C standard doesn't say so) for integers because
925 the value is not affected. For reals, the value might be
926 affected, so we can't. */
927 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
928 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
930 tree op0 = TREE_OPERAND (in, 0);
931 tree op1 = TREE_OPERAND (in, 1);
932 int neg1_p = TREE_CODE (in) == MINUS_EXPR;
933 int neg_litp_p = 0, neg_conp_p = 0, neg_var_p = 0;
935 /* First see if either of the operands is a literal, then a constant. */
936 if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST)
937 *litp = op0, op0 = 0;
938 else if (TREE_CODE (op1) == INTEGER_CST || TREE_CODE (op1) == REAL_CST)
939 *litp = op1, neg_litp_p = neg1_p, op1 = 0;
941 if (op0 != 0 && TREE_CONSTANT (op0))
942 *conp = op0, op0 = 0;
943 else if (op1 != 0 && TREE_CONSTANT (op1))
944 *conp = op1, neg_conp_p = neg1_p, op1 = 0;
946 /* If we haven't dealt with either operand, this is not a case we can
947 decompose. Otherwise, VAR is either of the ones remaining, if any. */
948 if (op0 != 0 && op1 != 0)
953 var = op1, neg_var_p = neg1_p;
955 /* Now do any needed negations. */
957 *minus_litp = *litp, *litp = 0;
959 *conp = negate_expr (*conp);
961 var = negate_expr (var);
963 else if (TREE_CONSTANT (in))
971 *minus_litp = *litp, *litp = 0;
972 else if (*minus_litp)
973 *litp = *minus_litp, *minus_litp = 0;
974 *conp = negate_expr (*conp);
975 var = negate_expr (var);
981 /* Re-associate trees split by the above function. T1 and T2 are either
982 expressions to associate or null. Return the new expression, if any. If
983 we build an operation, do it in TYPE and with CODE. */
986 associate_trees (t1, t2, code, type)
996 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
997 try to fold this since we will have infinite recursion. But do
998 deal with any NEGATE_EXPRs. */
999 if (TREE_CODE (t1) == code || TREE_CODE (t2) == code
1000 || TREE_CODE (t1) == MINUS_EXPR || TREE_CODE (t2) == MINUS_EXPR)
1002 if (code == PLUS_EXPR)
1004 if (TREE_CODE (t1) == NEGATE_EXPR)
1005 return build (MINUS_EXPR, type, convert (type, t2),
1006 convert (type, TREE_OPERAND (t1, 0)));
1007 else if (TREE_CODE (t2) == NEGATE_EXPR)
1008 return build (MINUS_EXPR, type, convert (type, t1),
1009 convert (type, TREE_OPERAND (t2, 0)));
1011 return build (code, type, convert (type, t1), convert (type, t2));
1014 return fold (build (code, type, convert (type, t1), convert (type, t2)));
1017 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1018 to produce a new constant.
1020 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1023 int_const_binop (code, arg1, arg2, notrunc)
1024 enum tree_code code;
1028 unsigned HOST_WIDE_INT int1l, int2l;
1029 HOST_WIDE_INT int1h, int2h;
1030 unsigned HOST_WIDE_INT low;
1032 unsigned HOST_WIDE_INT garbagel;
1033 HOST_WIDE_INT garbageh;
1035 tree type = TREE_TYPE (arg1);
1036 int uns = TREE_UNSIGNED (type);
1038 = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type));
1040 int no_overflow = 0;
1042 int1l = TREE_INT_CST_LOW (arg1);
1043 int1h = TREE_INT_CST_HIGH (arg1);
1044 int2l = TREE_INT_CST_LOW (arg2);
1045 int2h = TREE_INT_CST_HIGH (arg2);
1050 low = int1l | int2l, hi = int1h | int2h;
1054 low = int1l ^ int2l, hi = int1h ^ int2h;
1058 low = int1l & int2l, hi = int1h & int2h;
1061 case BIT_ANDTC_EXPR:
1062 low = int1l & ~int2l, hi = int1h & ~int2h;
1068 /* It's unclear from the C standard whether shifts can overflow.
1069 The following code ignores overflow; perhaps a C standard
1070 interpretation ruling is needed. */
1071 lshift_double (int1l, int1h, int2l, TYPE_PRECISION (type),
1079 lrotate_double (int1l, int1h, int2l, TYPE_PRECISION (type),
1084 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1088 neg_double (int2l, int2h, &low, &hi);
1089 add_double (int1l, int1h, low, hi, &low, &hi);
1090 overflow = OVERFLOW_SUM_SIGN (hi, int2h, int1h);
1094 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1097 case TRUNC_DIV_EXPR:
1098 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1099 case EXACT_DIV_EXPR:
1100 /* This is a shortcut for a common special case. */
1101 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
1102 && ! TREE_CONSTANT_OVERFLOW (arg1)
1103 && ! TREE_CONSTANT_OVERFLOW (arg2)
1104 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
1106 if (code == CEIL_DIV_EXPR)
1109 low = int1l / int2l, hi = 0;
1113 /* ... fall through ... */
1115 case ROUND_DIV_EXPR:
1116 if (int2h == 0 && int2l == 1)
1118 low = int1l, hi = int1h;
1121 if (int1l == int2l && int1h == int2h
1122 && ! (int1l == 0 && int1h == 0))
1127 overflow = div_and_round_double (code, uns, int1l, int1h, int2l, int2h,
1128 &low, &hi, &garbagel, &garbageh);
1131 case TRUNC_MOD_EXPR:
1132 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1133 /* This is a shortcut for a common special case. */
1134 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
1135 && ! TREE_CONSTANT_OVERFLOW (arg1)
1136 && ! TREE_CONSTANT_OVERFLOW (arg2)
1137 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
1139 if (code == CEIL_MOD_EXPR)
1141 low = int1l % int2l, hi = 0;
1145 /* ... fall through ... */
1147 case ROUND_MOD_EXPR:
1148 overflow = div_and_round_double (code, uns,
1149 int1l, int1h, int2l, int2h,
1150 &garbagel, &garbageh, &low, &hi);
1156 low = (((unsigned HOST_WIDE_INT) int1h
1157 < (unsigned HOST_WIDE_INT) int2h)
1158 || (((unsigned HOST_WIDE_INT) int1h
1159 == (unsigned HOST_WIDE_INT) int2h)
1162 low = (int1h < int2h
1163 || (int1h == int2h && int1l < int2l));
1165 if (low == (code == MIN_EXPR))
1166 low = int1l, hi = int1h;
1168 low = int2l, hi = int2h;
1175 /* If this is for a sizetype, can be represented as one (signed)
1176 HOST_WIDE_INT word, and doesn't overflow, use size_int since it caches
1179 && ((hi == 0 && (HOST_WIDE_INT) low >= 0)
1180 || (hi == -1 && (HOST_WIDE_INT) low < 0))
1181 && overflow == 0 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1182 return size_int_type_wide (low, type);
1185 t = build_int_2 (low, hi);
1186 TREE_TYPE (t) = TREE_TYPE (arg1);
1191 ? (!uns || is_sizetype) && overflow
1192 : (force_fit_type (t, (!uns || is_sizetype) && overflow)
1194 | TREE_OVERFLOW (arg1)
1195 | TREE_OVERFLOW (arg2));
1197 /* If we're doing a size calculation, unsigned arithmetic does overflow.
1198 So check if force_fit_type truncated the value. */
1200 && ! TREE_OVERFLOW (t)
1201 && (TREE_INT_CST_HIGH (t) != hi
1202 || TREE_INT_CST_LOW (t) != low))
1203 TREE_OVERFLOW (t) = 1;
1205 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1206 | TREE_CONSTANT_OVERFLOW (arg1)
1207 | TREE_CONSTANT_OVERFLOW (arg2));
1211 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1212 constant. We assume ARG1 and ARG2 have the same data type, or at least
1213 are the same kind of constant and the same machine mode.
1215 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1218 const_binop (code, arg1, arg2, notrunc)
1219 enum tree_code code;
1226 if (TREE_CODE (arg1) == INTEGER_CST)
1227 return int_const_binop (code, arg1, arg2, notrunc);
1229 if (TREE_CODE (arg1) == REAL_CST)
1233 REAL_VALUE_TYPE value;
1236 d1 = TREE_REAL_CST (arg1);
1237 d2 = TREE_REAL_CST (arg2);
1239 /* If either operand is a NaN, just return it. Otherwise, set up
1240 for floating-point trap; we return an overflow. */
1241 if (REAL_VALUE_ISNAN (d1))
1243 else if (REAL_VALUE_ISNAN (d2))
1246 REAL_ARITHMETIC (value, code, d1, d2);
1248 t = build_real (TREE_TYPE (arg1),
1249 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)),
1253 = (force_fit_type (t, 0)
1254 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1255 TREE_CONSTANT_OVERFLOW (t)
1257 | TREE_CONSTANT_OVERFLOW (arg1)
1258 | TREE_CONSTANT_OVERFLOW (arg2);
1261 if (TREE_CODE (arg1) == COMPLEX_CST)
1263 tree type = TREE_TYPE (arg1);
1264 tree r1 = TREE_REALPART (arg1);
1265 tree i1 = TREE_IMAGPART (arg1);
1266 tree r2 = TREE_REALPART (arg2);
1267 tree i2 = TREE_IMAGPART (arg2);
1273 t = build_complex (type,
1274 const_binop (PLUS_EXPR, r1, r2, notrunc),
1275 const_binop (PLUS_EXPR, i1, i2, notrunc));
1279 t = build_complex (type,
1280 const_binop (MINUS_EXPR, r1, r2, notrunc),
1281 const_binop (MINUS_EXPR, i1, i2, notrunc));
1285 t = build_complex (type,
1286 const_binop (MINUS_EXPR,
1287 const_binop (MULT_EXPR,
1289 const_binop (MULT_EXPR,
1292 const_binop (PLUS_EXPR,
1293 const_binop (MULT_EXPR,
1295 const_binop (MULT_EXPR,
1303 = const_binop (PLUS_EXPR,
1304 const_binop (MULT_EXPR, r2, r2, notrunc),
1305 const_binop (MULT_EXPR, i2, i2, notrunc),
1308 t = build_complex (type,
1310 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1311 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1312 const_binop (PLUS_EXPR,
1313 const_binop (MULT_EXPR, r1, r2,
1315 const_binop (MULT_EXPR, i1, i2,
1318 magsquared, notrunc),
1320 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1321 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1322 const_binop (MINUS_EXPR,
1323 const_binop (MULT_EXPR, i1, r2,
1325 const_binop (MULT_EXPR, r1, i2,
1328 magsquared, notrunc));
1340 /* These are the hash table functions for the hash table of INTEGER_CST
1341 nodes of a sizetype. */
1343 /* Return the hash code code X, an INTEGER_CST. */
1351 return (TREE_INT_CST_HIGH (t) ^ TREE_INT_CST_LOW (t)
1352 ^ htab_hash_pointer (TREE_TYPE (t))
1353 ^ (TREE_OVERFLOW (t) << 20));
1356 /* Return nonzero if the value represented by *X (an INTEGER_CST tree node)
1357 is the same as that given by *Y, which is the same. */
1367 return (TREE_INT_CST_HIGH (xt) == TREE_INT_CST_HIGH (yt)
1368 && TREE_INT_CST_LOW (xt) == TREE_INT_CST_LOW (yt)
1369 && TREE_TYPE (xt) == TREE_TYPE (yt)
1370 && TREE_OVERFLOW (xt) == TREE_OVERFLOW (yt));
1373 /* Return an INTEGER_CST with value whose low-order HOST_BITS_PER_WIDE_INT
1374 bits are given by NUMBER and of the sizetype represented by KIND. */
1377 size_int_wide (number, kind)
1378 HOST_WIDE_INT number;
1379 enum size_type_kind kind;
1381 return size_int_type_wide (number, sizetype_tab[(int) kind]);
1384 /* Likewise, but the desired type is specified explicitly. */
1386 static GTY (()) tree new_const;
1387 static GTY ((if_marked ("ggc_marked_p"), param_is (union tree_node)))
1391 size_int_type_wide (number, type)
1392 HOST_WIDE_INT number;
1399 size_htab = htab_create_ggc (1024, size_htab_hash, size_htab_eq, NULL);
1400 new_const = make_node (INTEGER_CST);
1403 /* Adjust NEW_CONST to be the constant we want. If it's already in the
1404 hash table, we return the value from the hash table. Otherwise, we
1405 place that in the hash table and make a new node for the next time. */
1406 TREE_INT_CST_LOW (new_const) = number;
1407 TREE_INT_CST_HIGH (new_const) = number < 0 ? -1 : 0;
1408 TREE_TYPE (new_const) = type;
1409 TREE_OVERFLOW (new_const) = TREE_CONSTANT_OVERFLOW (new_const)
1410 = force_fit_type (new_const, 0);
1412 slot = htab_find_slot (size_htab, new_const, INSERT);
1417 *slot = (PTR) new_const;
1418 new_const = make_node (INTEGER_CST);
1422 return (tree) *slot;
1425 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1426 is a tree code. The type of the result is taken from the operands.
1427 Both must be the same type integer type and it must be a size type.
1428 If the operands are constant, so is the result. */
1431 size_binop (code, arg0, arg1)
1432 enum tree_code code;
1435 tree type = TREE_TYPE (arg0);
1437 if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
1438 || type != TREE_TYPE (arg1))
1441 /* Handle the special case of two integer constants faster. */
1442 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1444 /* And some specific cases even faster than that. */
1445 if (code == PLUS_EXPR && integer_zerop (arg0))
1447 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1448 && integer_zerop (arg1))
1450 else if (code == MULT_EXPR && integer_onep (arg0))
1453 /* Handle general case of two integer constants. */
1454 return int_const_binop (code, arg0, arg1, 0);
1457 if (arg0 == error_mark_node || arg1 == error_mark_node)
1458 return error_mark_node;
1460 return fold (build (code, type, arg0, arg1));
1463 /* Given two values, either both of sizetype or both of bitsizetype,
1464 compute the difference between the two values. Return the value
1465 in signed type corresponding to the type of the operands. */
1468 size_diffop (arg0, arg1)
1471 tree type = TREE_TYPE (arg0);
1474 if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
1475 || type != TREE_TYPE (arg1))
1478 /* If the type is already signed, just do the simple thing. */
1479 if (! TREE_UNSIGNED (type))
1480 return size_binop (MINUS_EXPR, arg0, arg1);
1482 ctype = (type == bitsizetype || type == ubitsizetype
1483 ? sbitsizetype : ssizetype);
1485 /* If either operand is not a constant, do the conversions to the signed
1486 type and subtract. The hardware will do the right thing with any
1487 overflow in the subtraction. */
1488 if (TREE_CODE (arg0) != INTEGER_CST || TREE_CODE (arg1) != INTEGER_CST)
1489 return size_binop (MINUS_EXPR, convert (ctype, arg0),
1490 convert (ctype, arg1));
1492 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1493 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1494 overflow) and negate (which can't either). Special-case a result
1495 of zero while we're here. */
1496 if (tree_int_cst_equal (arg0, arg1))
1497 return convert (ctype, integer_zero_node);
1498 else if (tree_int_cst_lt (arg1, arg0))
1499 return convert (ctype, size_binop (MINUS_EXPR, arg0, arg1));
1501 return size_binop (MINUS_EXPR, convert (ctype, integer_zero_node),
1502 convert (ctype, size_binop (MINUS_EXPR, arg1, arg0)));
1506 /* Given T, a tree representing type conversion of ARG1, a constant,
1507 return a constant tree representing the result of conversion. */
1510 fold_convert (t, arg1)
1514 tree type = TREE_TYPE (t);
1517 if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
1519 if (TREE_CODE (arg1) == INTEGER_CST)
1521 /* If we would build a constant wider than GCC supports,
1522 leave the conversion unfolded. */
1523 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1526 /* If we are trying to make a sizetype for a small integer, use
1527 size_int to pick up cached types to reduce duplicate nodes. */
1528 if (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)
1529 && !TREE_CONSTANT_OVERFLOW (arg1)
1530 && compare_tree_int (arg1, 10000) < 0)
1531 return size_int_type_wide (TREE_INT_CST_LOW (arg1), type);
1533 /* Given an integer constant, make new constant with new type,
1534 appropriately sign-extended or truncated. */
1535 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1536 TREE_INT_CST_HIGH (arg1));
1537 TREE_TYPE (t) = type;
1538 /* Indicate an overflow if (1) ARG1 already overflowed,
1539 or (2) force_fit_type indicates an overflow.
1540 Tell force_fit_type that an overflow has already occurred
1541 if ARG1 is a too-large unsigned value and T is signed.
1542 But don't indicate an overflow if converting a pointer. */
1544 = ((force_fit_type (t,
1545 (TREE_INT_CST_HIGH (arg1) < 0
1546 && (TREE_UNSIGNED (type)
1547 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1548 && ! POINTER_TYPE_P (TREE_TYPE (arg1)))
1549 || TREE_OVERFLOW (arg1));
1550 TREE_CONSTANT_OVERFLOW (t)
1551 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1553 else if (TREE_CODE (arg1) == REAL_CST)
1555 /* Don't initialize these, use assignments.
1556 Initialized local aggregates don't work on old compilers. */
1560 tree type1 = TREE_TYPE (arg1);
1563 x = TREE_REAL_CST (arg1);
1564 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1566 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1567 if (!no_upper_bound)
1568 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1570 /* See if X will be in range after truncation towards 0.
1571 To compensate for truncation, move the bounds away from 0,
1572 but reject if X exactly equals the adjusted bounds. */
1573 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1574 if (!no_upper_bound)
1575 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1576 /* If X is a NaN, use zero instead and show we have an overflow.
1577 Otherwise, range check. */
1578 if (REAL_VALUE_ISNAN (x))
1579 overflow = 1, x = dconst0;
1580 else if (! (REAL_VALUES_LESS (l, x)
1582 && REAL_VALUES_LESS (x, u)))
1586 HOST_WIDE_INT low, high;
1587 REAL_VALUE_TO_INT (&low, &high, x);
1588 t = build_int_2 (low, high);
1590 TREE_TYPE (t) = type;
1592 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1593 TREE_CONSTANT_OVERFLOW (t)
1594 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1596 TREE_TYPE (t) = type;
1598 else if (TREE_CODE (type) == REAL_TYPE)
1600 if (TREE_CODE (arg1) == INTEGER_CST)
1601 return build_real_from_int_cst (type, arg1);
1602 if (TREE_CODE (arg1) == REAL_CST)
1604 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1606 /* We make a copy of ARG1 so that we don't modify an
1607 existing constant tree. */
1608 t = copy_node (arg1);
1609 TREE_TYPE (t) = type;
1613 t = build_real (type,
1614 real_value_truncate (TYPE_MODE (type),
1615 TREE_REAL_CST (arg1)));
1618 = TREE_OVERFLOW (arg1) | force_fit_type (t, 0);
1619 TREE_CONSTANT_OVERFLOW (t)
1620 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1624 TREE_CONSTANT (t) = 1;
1628 /* Return an expr equal to X but certainly not valid as an lvalue. */
1636 /* These things are certainly not lvalues. */
1637 if (TREE_CODE (x) == NON_LVALUE_EXPR
1638 || TREE_CODE (x) == INTEGER_CST
1639 || TREE_CODE (x) == REAL_CST
1640 || TREE_CODE (x) == STRING_CST
1641 || TREE_CODE (x) == ADDR_EXPR)
1644 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1645 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1649 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1650 Zero means allow extended lvalues. */
1652 int pedantic_lvalues;
1654 /* When pedantic, return an expr equal to X but certainly not valid as a
1655 pedantic lvalue. Otherwise, return X. */
1658 pedantic_non_lvalue (x)
1661 if (pedantic_lvalues)
1662 return non_lvalue (x);
1667 /* Given a tree comparison code, return the code that is the logical inverse
1668 of the given code. It is not safe to do this for floating-point
1669 comparisons, except for NE_EXPR and EQ_EXPR. */
1671 static enum tree_code
1672 invert_tree_comparison (code)
1673 enum tree_code code;
1694 /* Similar, but return the comparison that results if the operands are
1695 swapped. This is safe for floating-point. */
1697 static enum tree_code
1698 swap_tree_comparison (code)
1699 enum tree_code code;
1720 /* Convert a comparison tree code from an enum tree_code representation
1721 into a compcode bit-based encoding. This function is the inverse of
1722 compcode_to_comparison. */
1725 comparison_to_compcode (code)
1726 enum tree_code code;
1747 /* Convert a compcode bit-based encoding of a comparison operator back
1748 to GCC's enum tree_code representation. This function is the
1749 inverse of comparison_to_compcode. */
1751 static enum tree_code
1752 compcode_to_comparison (code)
1774 /* Return nonzero if CODE is a tree code that represents a truth value. */
1777 truth_value_p (code)
1778 enum tree_code code;
1780 return (TREE_CODE_CLASS (code) == '<'
1781 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1782 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1783 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1786 /* Return nonzero if two operands are necessarily equal.
1787 If ONLY_CONST is nonzero, only return nonzero for constants.
1788 This function tests whether the operands are indistinguishable;
1789 it does not test whether they are equal using C's == operation.
1790 The distinction is important for IEEE floating point, because
1791 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1792 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1795 operand_equal_p (arg0, arg1, only_const)
1799 /* If both types don't have the same signedness, then we can't consider
1800 them equal. We must check this before the STRIP_NOPS calls
1801 because they may change the signedness of the arguments. */
1802 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1808 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1809 /* This is needed for conversions and for COMPONENT_REF.
1810 Might as well play it safe and always test this. */
1811 || TREE_CODE (TREE_TYPE (arg0)) == ERROR_MARK
1812 || TREE_CODE (TREE_TYPE (arg1)) == ERROR_MARK
1813 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1816 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1817 We don't care about side effects in that case because the SAVE_EXPR
1818 takes care of that for us. In all other cases, two expressions are
1819 equal if they have no side effects. If we have two identical
1820 expressions with side effects that should be treated the same due
1821 to the only side effects being identical SAVE_EXPR's, that will
1822 be detected in the recursive calls below. */
1823 if (arg0 == arg1 && ! only_const
1824 && (TREE_CODE (arg0) == SAVE_EXPR
1825 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1828 /* Next handle constant cases, those for which we can return 1 even
1829 if ONLY_CONST is set. */
1830 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1831 switch (TREE_CODE (arg0))
1834 return (! TREE_CONSTANT_OVERFLOW (arg0)
1835 && ! TREE_CONSTANT_OVERFLOW (arg1)
1836 && tree_int_cst_equal (arg0, arg1));
1839 return (! TREE_CONSTANT_OVERFLOW (arg0)
1840 && ! TREE_CONSTANT_OVERFLOW (arg1)
1841 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
1842 TREE_REAL_CST (arg1)));
1848 if (TREE_CONSTANT_OVERFLOW (arg0)
1849 || TREE_CONSTANT_OVERFLOW (arg1))
1852 v1 = TREE_VECTOR_CST_ELTS (arg0);
1853 v2 = TREE_VECTOR_CST_ELTS (arg1);
1856 if (!operand_equal_p (v1, v2, only_const))
1858 v1 = TREE_CHAIN (v1);
1859 v2 = TREE_CHAIN (v2);
1866 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1868 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1872 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1873 && ! memcmp (TREE_STRING_POINTER (arg0),
1874 TREE_STRING_POINTER (arg1),
1875 TREE_STRING_LENGTH (arg0)));
1878 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1887 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1890 /* Two conversions are equal only if signedness and modes match. */
1891 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1892 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1893 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1896 return operand_equal_p (TREE_OPERAND (arg0, 0),
1897 TREE_OPERAND (arg1, 0), 0);
1901 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1902 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1906 /* For commutative ops, allow the other order. */
1907 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1908 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1909 || TREE_CODE (arg0) == BIT_IOR_EXPR
1910 || TREE_CODE (arg0) == BIT_XOR_EXPR
1911 || TREE_CODE (arg0) == BIT_AND_EXPR
1912 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1913 && operand_equal_p (TREE_OPERAND (arg0, 0),
1914 TREE_OPERAND (arg1, 1), 0)
1915 && operand_equal_p (TREE_OPERAND (arg0, 1),
1916 TREE_OPERAND (arg1, 0), 0));
1919 /* If either of the pointer (or reference) expressions we are dereferencing
1920 contain a side effect, these cannot be equal. */
1921 if (TREE_SIDE_EFFECTS (arg0)
1922 || TREE_SIDE_EFFECTS (arg1))
1925 switch (TREE_CODE (arg0))
1928 return operand_equal_p (TREE_OPERAND (arg0, 0),
1929 TREE_OPERAND (arg1, 0), 0);
1933 case ARRAY_RANGE_REF:
1934 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1935 TREE_OPERAND (arg1, 0), 0)
1936 && operand_equal_p (TREE_OPERAND (arg0, 1),
1937 TREE_OPERAND (arg1, 1), 0));
1940 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1941 TREE_OPERAND (arg1, 0), 0)
1942 && operand_equal_p (TREE_OPERAND (arg0, 1),
1943 TREE_OPERAND (arg1, 1), 0)
1944 && operand_equal_p (TREE_OPERAND (arg0, 2),
1945 TREE_OPERAND (arg1, 2), 0));
1951 if (TREE_CODE (arg0) == RTL_EXPR)
1952 return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
1960 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1961 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1963 When in doubt, return 0. */
1966 operand_equal_for_comparison_p (arg0, arg1, other)
1970 int unsignedp1, unsignedpo;
1971 tree primarg0, primarg1, primother;
1972 unsigned int correct_width;
1974 if (operand_equal_p (arg0, arg1, 0))
1977 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1978 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1981 /* Discard any conversions that don't change the modes of ARG0 and ARG1
1982 and see if the inner values are the same. This removes any
1983 signedness comparison, which doesn't matter here. */
1984 primarg0 = arg0, primarg1 = arg1;
1985 STRIP_NOPS (primarg0);
1986 STRIP_NOPS (primarg1);
1987 if (operand_equal_p (primarg0, primarg1, 0))
1990 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1991 actual comparison operand, ARG0.
1993 First throw away any conversions to wider types
1994 already present in the operands. */
1996 primarg1 = get_narrower (arg1, &unsignedp1);
1997 primother = get_narrower (other, &unsignedpo);
1999 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
2000 if (unsignedp1 == unsignedpo
2001 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
2002 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
2004 tree type = TREE_TYPE (arg0);
2006 /* Make sure shorter operand is extended the right way
2007 to match the longer operand. */
2008 primarg1 = convert ((*lang_hooks.types.signed_or_unsigned_type)
2009 (unsignedp1, TREE_TYPE (primarg1)), primarg1);
2011 if (operand_equal_p (arg0, convert (type, primarg1), 0))
2018 /* See if ARG is an expression that is either a comparison or is performing
2019 arithmetic on comparisons. The comparisons must only be comparing
2020 two different values, which will be stored in *CVAL1 and *CVAL2; if
2021 they are nonzero it means that some operands have already been found.
2022 No variables may be used anywhere else in the expression except in the
2023 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2024 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2026 If this is true, return 1. Otherwise, return zero. */
2029 twoval_comparison_p (arg, cval1, cval2, save_p)
2031 tree *cval1, *cval2;
2034 enum tree_code code = TREE_CODE (arg);
2035 char class = TREE_CODE_CLASS (code);
2037 /* We can handle some of the 'e' cases here. */
2038 if (class == 'e' && code == TRUTH_NOT_EXPR)
2040 else if (class == 'e'
2041 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
2042 || code == COMPOUND_EXPR))
2045 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0
2046 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
2048 /* If we've already found a CVAL1 or CVAL2, this expression is
2049 two complex to handle. */
2050 if (*cval1 || *cval2)
2060 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
2063 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
2064 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2065 cval1, cval2, save_p));
2071 if (code == COND_EXPR)
2072 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2073 cval1, cval2, save_p)
2074 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2075 cval1, cval2, save_p)
2076 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2077 cval1, cval2, save_p));
2081 /* First see if we can handle the first operand, then the second. For
2082 the second operand, we know *CVAL1 can't be zero. It must be that
2083 one side of the comparison is each of the values; test for the
2084 case where this isn't true by failing if the two operands
2087 if (operand_equal_p (TREE_OPERAND (arg, 0),
2088 TREE_OPERAND (arg, 1), 0))
2092 *cval1 = TREE_OPERAND (arg, 0);
2093 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2095 else if (*cval2 == 0)
2096 *cval2 = TREE_OPERAND (arg, 0);
2097 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2102 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2104 else if (*cval2 == 0)
2105 *cval2 = TREE_OPERAND (arg, 1);
2106 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2118 /* ARG is a tree that is known to contain just arithmetic operations and
2119 comparisons. Evaluate the operations in the tree substituting NEW0 for
2120 any occurrence of OLD0 as an operand of a comparison and likewise for
2124 eval_subst (arg, old0, new0, old1, new1)
2126 tree old0, new0, old1, new1;
2128 tree type = TREE_TYPE (arg);
2129 enum tree_code code = TREE_CODE (arg);
2130 char class = TREE_CODE_CLASS (code);
2132 /* We can handle some of the 'e' cases here. */
2133 if (class == 'e' && code == TRUTH_NOT_EXPR)
2135 else if (class == 'e'
2136 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2142 return fold (build1 (code, type,
2143 eval_subst (TREE_OPERAND (arg, 0),
2144 old0, new0, old1, new1)));
2147 return fold (build (code, type,
2148 eval_subst (TREE_OPERAND (arg, 0),
2149 old0, new0, old1, new1),
2150 eval_subst (TREE_OPERAND (arg, 1),
2151 old0, new0, old1, new1)));
2157 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2160 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2163 return fold (build (code, type,
2164 eval_subst (TREE_OPERAND (arg, 0),
2165 old0, new0, old1, new1),
2166 eval_subst (TREE_OPERAND (arg, 1),
2167 old0, new0, old1, new1),
2168 eval_subst (TREE_OPERAND (arg, 2),
2169 old0, new0, old1, new1)));
2173 /* fall through - ??? */
2177 tree arg0 = TREE_OPERAND (arg, 0);
2178 tree arg1 = TREE_OPERAND (arg, 1);
2180 /* We need to check both for exact equality and tree equality. The
2181 former will be true if the operand has a side-effect. In that
2182 case, we know the operand occurred exactly once. */
2184 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2186 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2189 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2191 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2194 return fold (build (code, type, arg0, arg1));
2202 /* Return a tree for the case when the result of an expression is RESULT
2203 converted to TYPE and OMITTED was previously an operand of the expression
2204 but is now not needed (e.g., we folded OMITTED * 0).
2206 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2207 the conversion of RESULT to TYPE. */
2210 omit_one_operand (type, result, omitted)
2211 tree type, result, omitted;
2213 tree t = convert (type, result);
2215 if (TREE_SIDE_EFFECTS (omitted))
2216 return build (COMPOUND_EXPR, type, omitted, t);
2218 return non_lvalue (t);
2221 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2224 pedantic_omit_one_operand (type, result, omitted)
2225 tree type, result, omitted;
2227 tree t = convert (type, result);
2229 if (TREE_SIDE_EFFECTS (omitted))
2230 return build (COMPOUND_EXPR, type, omitted, t);
2232 return pedantic_non_lvalue (t);
2235 /* Return a simplified tree node for the truth-negation of ARG. This
2236 never alters ARG itself. We assume that ARG is an operation that
2237 returns a truth value (0 or 1). */
2240 invert_truthvalue (arg)
2243 tree type = TREE_TYPE (arg);
2244 enum tree_code code = TREE_CODE (arg);
2246 if (code == ERROR_MARK)
2249 /* If this is a comparison, we can simply invert it, except for
2250 floating-point non-equality comparisons, in which case we just
2251 enclose a TRUTH_NOT_EXPR around what we have. */
2253 if (TREE_CODE_CLASS (code) == '<')
2255 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2256 && !flag_unsafe_math_optimizations
2259 return build1 (TRUTH_NOT_EXPR, type, arg);
2261 return build (invert_tree_comparison (code), type,
2262 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2268 return convert (type, build_int_2 (integer_zerop (arg), 0));
2270 case TRUTH_AND_EXPR:
2271 return build (TRUTH_OR_EXPR, type,
2272 invert_truthvalue (TREE_OPERAND (arg, 0)),
2273 invert_truthvalue (TREE_OPERAND (arg, 1)));
2276 return build (TRUTH_AND_EXPR, type,
2277 invert_truthvalue (TREE_OPERAND (arg, 0)),
2278 invert_truthvalue (TREE_OPERAND (arg, 1)));
2280 case TRUTH_XOR_EXPR:
2281 /* Here we can invert either operand. We invert the first operand
2282 unless the second operand is a TRUTH_NOT_EXPR in which case our
2283 result is the XOR of the first operand with the inside of the
2284 negation of the second operand. */
2286 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2287 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2288 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2290 return build (TRUTH_XOR_EXPR, type,
2291 invert_truthvalue (TREE_OPERAND (arg, 0)),
2292 TREE_OPERAND (arg, 1));
2294 case TRUTH_ANDIF_EXPR:
2295 return build (TRUTH_ORIF_EXPR, type,
2296 invert_truthvalue (TREE_OPERAND (arg, 0)),
2297 invert_truthvalue (TREE_OPERAND (arg, 1)));
2299 case TRUTH_ORIF_EXPR:
2300 return build (TRUTH_ANDIF_EXPR, type,
2301 invert_truthvalue (TREE_OPERAND (arg, 0)),
2302 invert_truthvalue (TREE_OPERAND (arg, 1)));
2304 case TRUTH_NOT_EXPR:
2305 return TREE_OPERAND (arg, 0);
2308 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2309 invert_truthvalue (TREE_OPERAND (arg, 1)),
2310 invert_truthvalue (TREE_OPERAND (arg, 2)));
2313 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2314 invert_truthvalue (TREE_OPERAND (arg, 1)));
2316 case WITH_RECORD_EXPR:
2317 return build (WITH_RECORD_EXPR, type,
2318 invert_truthvalue (TREE_OPERAND (arg, 0)),
2319 TREE_OPERAND (arg, 1));
2321 case NON_LVALUE_EXPR:
2322 return invert_truthvalue (TREE_OPERAND (arg, 0));
2327 return build1 (TREE_CODE (arg), type,
2328 invert_truthvalue (TREE_OPERAND (arg, 0)));
2331 if (!integer_onep (TREE_OPERAND (arg, 1)))
2333 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2336 return build1 (TRUTH_NOT_EXPR, type, arg);
2338 case CLEANUP_POINT_EXPR:
2339 return build1 (CLEANUP_POINT_EXPR, type,
2340 invert_truthvalue (TREE_OPERAND (arg, 0)));
2345 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2347 return build1 (TRUTH_NOT_EXPR, type, arg);
2350 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2351 operands are another bit-wise operation with a common input. If so,
2352 distribute the bit operations to save an operation and possibly two if
2353 constants are involved. For example, convert
2354 (A | B) & (A | C) into A | (B & C)
2355 Further simplification will occur if B and C are constants.
2357 If this optimization cannot be done, 0 will be returned. */
2360 distribute_bit_expr (code, type, arg0, arg1)
2361 enum tree_code code;
2368 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2369 || TREE_CODE (arg0) == code
2370 || (TREE_CODE (arg0) != BIT_AND_EXPR
2371 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2374 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2376 common = TREE_OPERAND (arg0, 0);
2377 left = TREE_OPERAND (arg0, 1);
2378 right = TREE_OPERAND (arg1, 1);
2380 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2382 common = TREE_OPERAND (arg0, 0);
2383 left = TREE_OPERAND (arg0, 1);
2384 right = TREE_OPERAND (arg1, 0);
2386 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2388 common = TREE_OPERAND (arg0, 1);
2389 left = TREE_OPERAND (arg0, 0);
2390 right = TREE_OPERAND (arg1, 1);
2392 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2394 common = TREE_OPERAND (arg0, 1);
2395 left = TREE_OPERAND (arg0, 0);
2396 right = TREE_OPERAND (arg1, 0);
2401 return fold (build (TREE_CODE (arg0), type, common,
2402 fold (build (code, type, left, right))));
2405 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2406 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
2409 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2412 int bitsize, bitpos;
2415 tree result = build (BIT_FIELD_REF, type, inner,
2416 size_int (bitsize), bitsize_int (bitpos));
2418 TREE_UNSIGNED (result) = unsignedp;
2423 /* Optimize a bit-field compare.
2425 There are two cases: First is a compare against a constant and the
2426 second is a comparison of two items where the fields are at the same
2427 bit position relative to the start of a chunk (byte, halfword, word)
2428 large enough to contain it. In these cases we can avoid the shift
2429 implicit in bitfield extractions.
2431 For constants, we emit a compare of the shifted constant with the
2432 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2433 compared. For two fields at the same position, we do the ANDs with the
2434 similar mask and compare the result of the ANDs.
2436 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2437 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2438 are the left and right operands of the comparison, respectively.
2440 If the optimization described above can be done, we return the resulting
2441 tree. Otherwise we return zero. */
2444 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2445 enum tree_code code;
2449 HOST_WIDE_INT lbitpos, lbitsize, rbitpos, rbitsize, nbitpos, nbitsize;
2450 tree type = TREE_TYPE (lhs);
2451 tree signed_type, unsigned_type;
2452 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2453 enum machine_mode lmode, rmode, nmode;
2454 int lunsignedp, runsignedp;
2455 int lvolatilep = 0, rvolatilep = 0;
2456 tree linner, rinner = NULL_TREE;
2460 /* Get all the information about the extractions being done. If the bit size
2461 if the same as the size of the underlying object, we aren't doing an
2462 extraction at all and so can do nothing. We also don't want to
2463 do anything if the inner expression is a PLACEHOLDER_EXPR since we
2464 then will no longer be able to replace it. */
2465 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2466 &lunsignedp, &lvolatilep);
2467 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2468 || offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR)
2473 /* If this is not a constant, we can only do something if bit positions,
2474 sizes, and signedness are the same. */
2475 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2476 &runsignedp, &rvolatilep);
2478 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2479 || lunsignedp != runsignedp || offset != 0
2480 || TREE_CODE (rinner) == PLACEHOLDER_EXPR)
2484 /* See if we can find a mode to refer to this field. We should be able to,
2485 but fail if we can't. */
2486 nmode = get_best_mode (lbitsize, lbitpos,
2487 const_p ? TYPE_ALIGN (TREE_TYPE (linner))
2488 : MIN (TYPE_ALIGN (TREE_TYPE (linner)),
2489 TYPE_ALIGN (TREE_TYPE (rinner))),
2490 word_mode, lvolatilep || rvolatilep);
2491 if (nmode == VOIDmode)
2494 /* Set signed and unsigned types of the precision of this mode for the
2496 signed_type = (*lang_hooks.types.type_for_mode) (nmode, 0);
2497 unsigned_type = (*lang_hooks.types.type_for_mode) (nmode, 1);
2499 /* Compute the bit position and size for the new reference and our offset
2500 within it. If the new reference is the same size as the original, we
2501 won't optimize anything, so return zero. */
2502 nbitsize = GET_MODE_BITSIZE (nmode);
2503 nbitpos = lbitpos & ~ (nbitsize - 1);
2505 if (nbitsize == lbitsize)
2508 if (BYTES_BIG_ENDIAN)
2509 lbitpos = nbitsize - lbitsize - lbitpos;
2511 /* Make the mask to be used against the extracted field. */
2512 mask = build_int_2 (~0, ~0);
2513 TREE_TYPE (mask) = unsigned_type;
2514 force_fit_type (mask, 0);
2515 mask = convert (unsigned_type, mask);
2516 mask = const_binop (LSHIFT_EXPR, mask, size_int (nbitsize - lbitsize), 0);
2517 mask = const_binop (RSHIFT_EXPR, mask,
2518 size_int (nbitsize - lbitsize - lbitpos), 0);
2521 /* If not comparing with constant, just rework the comparison
2523 return build (code, compare_type,
2524 build (BIT_AND_EXPR, unsigned_type,
2525 make_bit_field_ref (linner, unsigned_type,
2526 nbitsize, nbitpos, 1),
2528 build (BIT_AND_EXPR, unsigned_type,
2529 make_bit_field_ref (rinner, unsigned_type,
2530 nbitsize, nbitpos, 1),
2533 /* Otherwise, we are handling the constant case. See if the constant is too
2534 big for the field. Warn and return a tree of for 0 (false) if so. We do
2535 this not only for its own sake, but to avoid having to test for this
2536 error case below. If we didn't, we might generate wrong code.
2538 For unsigned fields, the constant shifted right by the field length should
2539 be all zero. For signed fields, the high-order bits should agree with
2544 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2545 convert (unsigned_type, rhs),
2546 size_int (lbitsize), 0)))
2548 warning ("comparison is always %d due to width of bit-field",
2550 return convert (compare_type,
2552 ? integer_one_node : integer_zero_node));
2557 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2558 size_int (lbitsize - 1), 0);
2559 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2561 warning ("comparison is always %d due to width of bit-field",
2563 return convert (compare_type,
2565 ? integer_one_node : integer_zero_node));
2569 /* Single-bit compares should always be against zero. */
2570 if (lbitsize == 1 && ! integer_zerop (rhs))
2572 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2573 rhs = convert (type, integer_zero_node);
2576 /* Make a new bitfield reference, shift the constant over the
2577 appropriate number of bits and mask it with the computed mask
2578 (in case this was a signed field). If we changed it, make a new one. */
2579 lhs = make_bit_field_ref (linner, unsigned_type, nbitsize, nbitpos, 1);
2582 TREE_SIDE_EFFECTS (lhs) = 1;
2583 TREE_THIS_VOLATILE (lhs) = 1;
2586 rhs = fold (const_binop (BIT_AND_EXPR,
2587 const_binop (LSHIFT_EXPR,
2588 convert (unsigned_type, rhs),
2589 size_int (lbitpos), 0),
2592 return build (code, compare_type,
2593 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2597 /* Subroutine for fold_truthop: decode a field reference.
2599 If EXP is a comparison reference, we return the innermost reference.
2601 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2602 set to the starting bit number.
2604 If the innermost field can be completely contained in a mode-sized
2605 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2607 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2608 otherwise it is not changed.
2610 *PUNSIGNEDP is set to the signedness of the field.
2612 *PMASK is set to the mask used. This is either contained in a
2613 BIT_AND_EXPR or derived from the width of the field.
2615 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
2617 Return 0 if this is not a component reference or is one that we can't
2618 do anything with. */
2621 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2622 pvolatilep, pmask, pand_mask)
2624 HOST_WIDE_INT *pbitsize, *pbitpos;
2625 enum machine_mode *pmode;
2626 int *punsignedp, *pvolatilep;
2631 tree mask, inner, offset;
2633 unsigned int precision;
2635 /* All the optimizations using this function assume integer fields.
2636 There are problems with FP fields since the type_for_size call
2637 below can fail for, e.g., XFmode. */
2638 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2643 if (TREE_CODE (exp) == BIT_AND_EXPR)
2645 and_mask = TREE_OPERAND (exp, 1);
2646 exp = TREE_OPERAND (exp, 0);
2647 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2648 if (TREE_CODE (and_mask) != INTEGER_CST)
2652 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2653 punsignedp, pvolatilep);
2654 if ((inner == exp && and_mask == 0)
2655 || *pbitsize < 0 || offset != 0
2656 || TREE_CODE (inner) == PLACEHOLDER_EXPR)
2659 /* Compute the mask to access the bitfield. */
2660 unsigned_type = (*lang_hooks.types.type_for_size) (*pbitsize, 1);
2661 precision = TYPE_PRECISION (unsigned_type);
2663 mask = build_int_2 (~0, ~0);
2664 TREE_TYPE (mask) = unsigned_type;
2665 force_fit_type (mask, 0);
2666 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2667 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2669 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2671 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2672 convert (unsigned_type, and_mask), mask));
2675 *pand_mask = and_mask;
2679 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
2683 all_ones_mask_p (mask, size)
2687 tree type = TREE_TYPE (mask);
2688 unsigned int precision = TYPE_PRECISION (type);
2691 tmask = build_int_2 (~0, ~0);
2692 TREE_TYPE (tmask) = (*lang_hooks.types.signed_type) (type);
2693 force_fit_type (tmask, 0);
2695 tree_int_cst_equal (mask,
2696 const_binop (RSHIFT_EXPR,
2697 const_binop (LSHIFT_EXPR, tmask,
2698 size_int (precision - size),
2700 size_int (precision - size), 0));
2703 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
2704 represents the sign bit of EXP's type. If EXP represents a sign
2705 or zero extension, also test VAL against the unextended type.
2706 The return value is the (sub)expression whose sign bit is VAL,
2707 or NULL_TREE otherwise. */
2710 sign_bit_p (exp, val)
2714 unsigned HOST_WIDE_INT lo;
2719 /* Tree EXP must have an integral type. */
2720 t = TREE_TYPE (exp);
2721 if (! INTEGRAL_TYPE_P (t))
2724 /* Tree VAL must be an integer constant. */
2725 if (TREE_CODE (val) != INTEGER_CST
2726 || TREE_CONSTANT_OVERFLOW (val))
2729 width = TYPE_PRECISION (t);
2730 if (width > HOST_BITS_PER_WIDE_INT)
2732 hi = (unsigned HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT - 1);
2738 lo = (unsigned HOST_WIDE_INT) 1 << (width - 1);
2741 if (TREE_INT_CST_HIGH (val) == hi && TREE_INT_CST_LOW (val) == lo)
2744 /* Handle extension from a narrower type. */
2745 if (TREE_CODE (exp) == NOP_EXPR
2746 && TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0))) < width)
2747 return sign_bit_p (TREE_OPERAND (exp, 0), val);
2752 /* Subroutine for fold_truthop: determine if an operand is simple enough
2753 to be evaluated unconditionally. */
2756 simple_operand_p (exp)
2759 /* Strip any conversions that don't change the machine mode. */
2760 while ((TREE_CODE (exp) == NOP_EXPR
2761 || TREE_CODE (exp) == CONVERT_EXPR)
2762 && (TYPE_MODE (TREE_TYPE (exp))
2763 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2764 exp = TREE_OPERAND (exp, 0);
2766 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2768 && ! TREE_ADDRESSABLE (exp)
2769 && ! TREE_THIS_VOLATILE (exp)
2770 && ! DECL_NONLOCAL (exp)
2771 /* Don't regard global variables as simple. They may be
2772 allocated in ways unknown to the compiler (shared memory,
2773 #pragma weak, etc). */
2774 && ! TREE_PUBLIC (exp)
2775 && ! DECL_EXTERNAL (exp)
2776 /* Loading a static variable is unduly expensive, but global
2777 registers aren't expensive. */
2778 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2781 /* The following functions are subroutines to fold_range_test and allow it to
2782 try to change a logical combination of comparisons into a range test.
2785 X == 2 || X == 3 || X == 4 || X == 5
2789 (unsigned) (X - 2) <= 3
2791 We describe each set of comparisons as being either inside or outside
2792 a range, using a variable named like IN_P, and then describe the
2793 range with a lower and upper bound. If one of the bounds is omitted,
2794 it represents either the highest or lowest value of the type.
2796 In the comments below, we represent a range by two numbers in brackets
2797 preceded by a "+" to designate being inside that range, or a "-" to
2798 designate being outside that range, so the condition can be inverted by
2799 flipping the prefix. An omitted bound is represented by a "-". For
2800 example, "- [-, 10]" means being outside the range starting at the lowest
2801 possible value and ending at 10, in other words, being greater than 10.
2802 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2805 We set up things so that the missing bounds are handled in a consistent
2806 manner so neither a missing bound nor "true" and "false" need to be
2807 handled using a special case. */
2809 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2810 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2811 and UPPER1_P are nonzero if the respective argument is an upper bound
2812 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2813 must be specified for a comparison. ARG1 will be converted to ARG0's
2814 type if both are specified. */
2817 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2818 enum tree_code code;
2821 int upper0_p, upper1_p;
2827 /* If neither arg represents infinity, do the normal operation.
2828 Else, if not a comparison, return infinity. Else handle the special
2829 comparison rules. Note that most of the cases below won't occur, but
2830 are handled for consistency. */
2832 if (arg0 != 0 && arg1 != 0)
2834 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2835 arg0, convert (TREE_TYPE (arg0), arg1)));
2837 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2840 if (TREE_CODE_CLASS (code) != '<')
2843 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2844 for neither. In real maths, we cannot assume open ended ranges are
2845 the same. But, this is computer arithmetic, where numbers are finite.
2846 We can therefore make the transformation of any unbounded range with
2847 the value Z, Z being greater than any representable number. This permits
2848 us to treat unbounded ranges as equal. */
2849 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2850 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2854 result = sgn0 == sgn1;
2857 result = sgn0 != sgn1;
2860 result = sgn0 < sgn1;
2863 result = sgn0 <= sgn1;
2866 result = sgn0 > sgn1;
2869 result = sgn0 >= sgn1;
2875 return convert (type, result ? integer_one_node : integer_zero_node);
2878 /* Given EXP, a logical expression, set the range it is testing into
2879 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2880 actually being tested. *PLOW and *PHIGH will be made of the same type
2881 as the returned expression. If EXP is not a comparison, we will most
2882 likely not be returning a useful value and range. */
2885 make_range (exp, pin_p, plow, phigh)
2890 enum tree_code code;
2891 tree arg0 = NULL_TREE, arg1 = NULL_TREE, type = NULL_TREE;
2892 tree orig_type = NULL_TREE;
2894 tree low, high, n_low, n_high;
2896 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2897 and see if we can refine the range. Some of the cases below may not
2898 happen, but it doesn't seem worth worrying about this. We "continue"
2899 the outer loop when we've changed something; otherwise we "break"
2900 the switch, which will "break" the while. */
2902 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2906 code = TREE_CODE (exp);
2908 if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
2910 arg0 = TREE_OPERAND (exp, 0);
2911 if (TREE_CODE_CLASS (code) == '<'
2912 || TREE_CODE_CLASS (code) == '1'
2913 || TREE_CODE_CLASS (code) == '2')
2914 type = TREE_TYPE (arg0);
2915 if (TREE_CODE_CLASS (code) == '2'
2916 || TREE_CODE_CLASS (code) == '<'
2917 || (TREE_CODE_CLASS (code) == 'e'
2918 && TREE_CODE_LENGTH (code) > 1))
2919 arg1 = TREE_OPERAND (exp, 1);
2922 /* Set ORIG_TYPE as soon as TYPE is non-null so that we do not
2923 lose a cast by accident. */
2924 if (type != NULL_TREE && orig_type == NULL_TREE)
2929 case TRUTH_NOT_EXPR:
2930 in_p = ! in_p, exp = arg0;
2933 case EQ_EXPR: case NE_EXPR:
2934 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2935 /* We can only do something if the range is testing for zero
2936 and if the second operand is an integer constant. Note that
2937 saying something is "in" the range we make is done by
2938 complementing IN_P since it will set in the initial case of
2939 being not equal to zero; "out" is leaving it alone. */
2940 if (low == 0 || high == 0
2941 || ! integer_zerop (low) || ! integer_zerop (high)
2942 || TREE_CODE (arg1) != INTEGER_CST)
2947 case NE_EXPR: /* - [c, c] */
2950 case EQ_EXPR: /* + [c, c] */
2951 in_p = ! in_p, low = high = arg1;
2953 case GT_EXPR: /* - [-, c] */
2954 low = 0, high = arg1;
2956 case GE_EXPR: /* + [c, -] */
2957 in_p = ! in_p, low = arg1, high = 0;
2959 case LT_EXPR: /* - [c, -] */
2960 low = arg1, high = 0;
2962 case LE_EXPR: /* + [-, c] */
2963 in_p = ! in_p, low = 0, high = arg1;
2971 /* If this is an unsigned comparison, we also know that EXP is
2972 greater than or equal to zero. We base the range tests we make
2973 on that fact, so we record it here so we can parse existing
2975 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2977 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2978 1, convert (type, integer_zero_node),
2982 in_p = n_in_p, low = n_low, high = n_high;
2984 /* If the high bound is missing, but we
2985 have a low bound, reverse the range so
2986 it goes from zero to the low bound minus 1. */
2987 if (high == 0 && low)
2990 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2991 integer_one_node, 0);
2992 low = convert (type, integer_zero_node);
2998 /* (-x) IN [a,b] -> x in [-b, -a] */
2999 n_low = range_binop (MINUS_EXPR, type,
3000 convert (type, integer_zero_node), 0, high, 1);
3001 n_high = range_binop (MINUS_EXPR, type,
3002 convert (type, integer_zero_node), 0, low, 0);
3003 low = n_low, high = n_high;
3009 exp = build (MINUS_EXPR, type, negate_expr (arg0),
3010 convert (type, integer_one_node));
3013 case PLUS_EXPR: case MINUS_EXPR:
3014 if (TREE_CODE (arg1) != INTEGER_CST)
3017 /* If EXP is signed, any overflow in the computation is undefined,
3018 so we don't worry about it so long as our computations on
3019 the bounds don't overflow. For unsigned, overflow is defined
3020 and this is exactly the right thing. */
3021 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3022 type, low, 0, arg1, 0);
3023 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3024 type, high, 1, arg1, 0);
3025 if ((n_low != 0 && TREE_OVERFLOW (n_low))
3026 || (n_high != 0 && TREE_OVERFLOW (n_high)))
3029 /* Check for an unsigned range which has wrapped around the maximum
3030 value thus making n_high < n_low, and normalize it. */
3031 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
3033 low = range_binop (PLUS_EXPR, type, n_high, 0,
3034 integer_one_node, 0);
3035 high = range_binop (MINUS_EXPR, type, n_low, 0,
3036 integer_one_node, 0);
3038 /* If the range is of the form +/- [ x+1, x ], we won't
3039 be able to normalize it. But then, it represents the
3040 whole range or the empty set, so make it
3042 if (tree_int_cst_equal (n_low, low)
3043 && tree_int_cst_equal (n_high, high))
3049 low = n_low, high = n_high;
3054 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
3055 if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
3058 if (! INTEGRAL_TYPE_P (type)
3059 || (low != 0 && ! int_fits_type_p (low, type))
3060 || (high != 0 && ! int_fits_type_p (high, type)))
3063 n_low = low, n_high = high;
3066 n_low = convert (type, n_low);
3069 n_high = convert (type, n_high);
3071 /* If we're converting from an unsigned to a signed type,
3072 we will be doing the comparison as unsigned. The tests above
3073 have already verified that LOW and HIGH are both positive.
3075 So we have to make sure that the original unsigned value will
3076 be interpreted as positive. */
3077 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
3079 tree equiv_type = (*lang_hooks.types.type_for_mode)
3080 (TYPE_MODE (type), 1);
3083 /* A range without an upper bound is, naturally, unbounded.
3084 Since convert would have cropped a very large value, use
3085 the max value for the destination type. */
3087 = TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type)
3088 : TYPE_MAX_VALUE (type);
3090 if (TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (exp)))
3091 high_positive = fold (build (RSHIFT_EXPR, type,
3092 convert (type, high_positive),
3093 convert (type, integer_one_node)));
3095 /* If the low bound is specified, "and" the range with the
3096 range for which the original unsigned value will be
3100 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3102 1, convert (type, integer_zero_node),
3106 in_p = (n_in_p == in_p);
3110 /* Otherwise, "or" the range with the range of the input
3111 that will be interpreted as negative. */
3112 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3114 1, convert (type, integer_zero_node),
3118 in_p = (in_p != n_in_p);
3123 low = n_low, high = n_high;
3133 /* If EXP is a constant, we can evaluate whether this is true or false. */
3134 if (TREE_CODE (exp) == INTEGER_CST)
3136 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
3138 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3144 *pin_p = in_p, *plow = low, *phigh = high;
3148 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3149 type, TYPE, return an expression to test if EXP is in (or out of, depending
3150 on IN_P) the range. */
3153 build_range_check (type, exp, in_p, low, high)
3159 tree etype = TREE_TYPE (exp);
3163 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3164 return invert_truthvalue (value);
3166 if (low == 0 && high == 0)
3167 return convert (type, integer_one_node);
3170 return fold (build (LE_EXPR, type, exp, high));
3173 return fold (build (GE_EXPR, type, exp, low));
3175 if (operand_equal_p (low, high, 0))
3176 return fold (build (EQ_EXPR, type, exp, low));
3178 if (integer_zerop (low))
3180 if (! TREE_UNSIGNED (etype))
3182 etype = (*lang_hooks.types.unsigned_type) (etype);
3183 high = convert (etype, high);
3184 exp = convert (etype, exp);
3186 return build_range_check (type, exp, 1, 0, high);
3189 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
3190 if (integer_onep (low) && TREE_CODE (high) == INTEGER_CST)
3192 unsigned HOST_WIDE_INT lo;
3196 prec = TYPE_PRECISION (etype);
3197 if (prec <= HOST_BITS_PER_WIDE_INT)
3200 lo = ((unsigned HOST_WIDE_INT) 1 << (prec - 1)) - 1;
3204 hi = ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)) - 1;
3205 lo = (unsigned HOST_WIDE_INT) -1;
3208 if (TREE_INT_CST_HIGH (high) == hi && TREE_INT_CST_LOW (high) == lo)
3210 if (TREE_UNSIGNED (etype))
3212 etype = (*lang_hooks.types.signed_type) (etype);
3213 exp = convert (etype, exp);
3215 return fold (build (GT_EXPR, type, exp,
3216 convert (etype, integer_zero_node)));
3220 if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3221 && ! TREE_OVERFLOW (value))
3222 return build_range_check (type,
3223 fold (build (MINUS_EXPR, etype, exp, low)),
3224 1, convert (etype, integer_zero_node), value);
3229 /* Given two ranges, see if we can merge them into one. Return 1 if we
3230 can, 0 if we can't. Set the output range into the specified parameters. */
3233 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3237 tree low0, high0, low1, high1;
3245 int lowequal = ((low0 == 0 && low1 == 0)
3246 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3247 low0, 0, low1, 0)));
3248 int highequal = ((high0 == 0 && high1 == 0)
3249 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3250 high0, 1, high1, 1)));
3252 /* Make range 0 be the range that starts first, or ends last if they
3253 start at the same value. Swap them if it isn't. */
3254 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3257 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3258 high1, 1, high0, 1))))
3260 temp = in0_p, in0_p = in1_p, in1_p = temp;
3261 tem = low0, low0 = low1, low1 = tem;
3262 tem = high0, high0 = high1, high1 = tem;
3265 /* Now flag two cases, whether the ranges are disjoint or whether the
3266 second range is totally subsumed in the first. Note that the tests
3267 below are simplified by the ones above. */
3268 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3269 high0, 1, low1, 0));
3270 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3271 high1, 1, high0, 1));
3273 /* We now have four cases, depending on whether we are including or
3274 excluding the two ranges. */
3277 /* If they don't overlap, the result is false. If the second range
3278 is a subset it is the result. Otherwise, the range is from the start
3279 of the second to the end of the first. */
3281 in_p = 0, low = high = 0;
3283 in_p = 1, low = low1, high = high1;
3285 in_p = 1, low = low1, high = high0;
3288 else if (in0_p && ! in1_p)
3290 /* If they don't overlap, the result is the first range. If they are
3291 equal, the result is false. If the second range is a subset of the
3292 first, and the ranges begin at the same place, we go from just after
3293 the end of the first range to the end of the second. If the second
3294 range is not a subset of the first, or if it is a subset and both
3295 ranges end at the same place, the range starts at the start of the
3296 first range and ends just before the second range.
3297 Otherwise, we can't describe this as a single range. */
3299 in_p = 1, low = low0, high = high0;
3300 else if (lowequal && highequal)
3301 in_p = 0, low = high = 0;
3302 else if (subset && lowequal)
3304 in_p = 1, high = high0;
3305 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3306 integer_one_node, 0);
3308 else if (! subset || highequal)
3310 in_p = 1, low = low0;
3311 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3312 integer_one_node, 0);
3318 else if (! in0_p && in1_p)
3320 /* If they don't overlap, the result is the second range. If the second
3321 is a subset of the first, the result is false. Otherwise,
3322 the range starts just after the first range and ends at the
3323 end of the second. */
3325 in_p = 1, low = low1, high = high1;
3326 else if (subset || highequal)
3327 in_p = 0, low = high = 0;
3330 in_p = 1, high = high1;
3331 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3332 integer_one_node, 0);
3338 /* The case where we are excluding both ranges. Here the complex case
3339 is if they don't overlap. In that case, the only time we have a
3340 range is if they are adjacent. If the second is a subset of the
3341 first, the result is the first. Otherwise, the range to exclude
3342 starts at the beginning of the first range and ends at the end of the
3346 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3347 range_binop (PLUS_EXPR, NULL_TREE,
3349 integer_one_node, 1),
3351 in_p = 0, low = low0, high = high1;
3356 in_p = 0, low = low0, high = high0;
3358 in_p = 0, low = low0, high = high1;
3361 *pin_p = in_p, *plow = low, *phigh = high;
3365 /* EXP is some logical combination of boolean tests. See if we can
3366 merge it into some range test. Return the new tree if so. */
3369 fold_range_test (exp)
3372 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3373 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3374 int in0_p, in1_p, in_p;
3375 tree low0, low1, low, high0, high1, high;
3376 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3377 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3380 /* If this is an OR operation, invert both sides; we will invert
3381 again at the end. */
3383 in0_p = ! in0_p, in1_p = ! in1_p;
3385 /* If both expressions are the same, if we can merge the ranges, and we
3386 can build the range test, return it or it inverted. If one of the
3387 ranges is always true or always false, consider it to be the same
3388 expression as the other. */
3389 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3390 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3392 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3394 : rhs != 0 ? rhs : integer_zero_node,
3396 return or_op ? invert_truthvalue (tem) : tem;
3398 /* On machines where the branch cost is expensive, if this is a
3399 short-circuited branch and the underlying object on both sides
3400 is the same, make a non-short-circuit operation. */
3401 else if (BRANCH_COST >= 2
3402 && lhs != 0 && rhs != 0
3403 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3404 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3405 && operand_equal_p (lhs, rhs, 0))
3407 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3408 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
3409 which cases we can't do this. */
3410 if (simple_operand_p (lhs))
3411 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3412 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3413 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3414 TREE_OPERAND (exp, 1));
3416 else if ((*lang_hooks.decls.global_bindings_p) () == 0
3417 && ! contains_placeholder_p (lhs))
3419 tree common = save_expr (lhs);
3421 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3422 or_op ? ! in0_p : in0_p,
3424 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3425 or_op ? ! in1_p : in1_p,
3427 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3428 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3429 TREE_TYPE (exp), lhs, rhs);
3436 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3437 bit value. Arrange things so the extra bits will be set to zero if and
3438 only if C is signed-extended to its full width. If MASK is nonzero,
3439 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3442 unextend (c, p, unsignedp, mask)
3448 tree type = TREE_TYPE (c);
3449 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3452 if (p == modesize || unsignedp)
3455 /* We work by getting just the sign bit into the low-order bit, then
3456 into the high-order bit, then sign-extend. We then XOR that value
3458 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3459 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3461 /* We must use a signed type in order to get an arithmetic right shift.
3462 However, we must also avoid introducing accidental overflows, so that
3463 a subsequent call to integer_zerop will work. Hence we must
3464 do the type conversion here. At this point, the constant is either
3465 zero or one, and the conversion to a signed type can never overflow.
3466 We could get an overflow if this conversion is done anywhere else. */
3467 if (TREE_UNSIGNED (type))
3468 temp = convert ((*lang_hooks.types.signed_type) (type), temp);
3470 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3471 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3473 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3474 /* If necessary, convert the type back to match the type of C. */
3475 if (TREE_UNSIGNED (type))
3476 temp = convert (type, temp);
3478 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3481 /* Find ways of folding logical expressions of LHS and RHS:
3482 Try to merge two comparisons to the same innermost item.
3483 Look for range tests like "ch >= '0' && ch <= '9'".
3484 Look for combinations of simple terms on machines with expensive branches
3485 and evaluate the RHS unconditionally.
3487 For example, if we have p->a == 2 && p->b == 4 and we can make an
3488 object large enough to span both A and B, we can do this with a comparison
3489 against the object ANDed with the a mask.
3491 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3492 operations to do this with one comparison.
3494 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3495 function and the one above.
3497 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3498 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3500 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3503 We return the simplified tree or 0 if no optimization is possible. */
3506 fold_truthop (code, truth_type, lhs, rhs)
3507 enum tree_code code;
3508 tree truth_type, lhs, rhs;
3510 /* If this is the "or" of two comparisons, we can do something if
3511 the comparisons are NE_EXPR. If this is the "and", we can do something
3512 if the comparisons are EQ_EXPR. I.e.,
3513 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3515 WANTED_CODE is this operation code. For single bit fields, we can
3516 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3517 comparison for one-bit fields. */
3519 enum tree_code wanted_code;
3520 enum tree_code lcode, rcode;
3521 tree ll_arg, lr_arg, rl_arg, rr_arg;
3522 tree ll_inner, lr_inner, rl_inner, rr_inner;
3523 HOST_WIDE_INT ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3524 HOST_WIDE_INT rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3525 HOST_WIDE_INT xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3526 HOST_WIDE_INT lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3527 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3528 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3529 enum machine_mode lnmode, rnmode;
3530 tree ll_mask, lr_mask, rl_mask, rr_mask;
3531 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3532 tree l_const, r_const;
3533 tree lntype, rntype, result;
3534 int first_bit, end_bit;
3537 /* Start by getting the comparison codes. Fail if anything is volatile.
3538 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3539 it were surrounded with a NE_EXPR. */
3541 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3544 lcode = TREE_CODE (lhs);
3545 rcode = TREE_CODE (rhs);
3547 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3548 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3550 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3551 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3553 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3556 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3557 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3559 ll_arg = TREE_OPERAND (lhs, 0);
3560 lr_arg = TREE_OPERAND (lhs, 1);
3561 rl_arg = TREE_OPERAND (rhs, 0);
3562 rr_arg = TREE_OPERAND (rhs, 1);
3564 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
3565 if (simple_operand_p (ll_arg)
3566 && simple_operand_p (lr_arg)
3567 && !FLOAT_TYPE_P (TREE_TYPE (ll_arg)))
3571 if (operand_equal_p (ll_arg, rl_arg, 0)
3572 && operand_equal_p (lr_arg, rr_arg, 0))
3574 int lcompcode, rcompcode;
3576 lcompcode = comparison_to_compcode (lcode);
3577 rcompcode = comparison_to_compcode (rcode);
3578 compcode = (code == TRUTH_AND_EXPR)
3579 ? lcompcode & rcompcode
3580 : lcompcode | rcompcode;
3582 else if (operand_equal_p (ll_arg, rr_arg, 0)
3583 && operand_equal_p (lr_arg, rl_arg, 0))
3585 int lcompcode, rcompcode;
3587 rcode = swap_tree_comparison (rcode);
3588 lcompcode = comparison_to_compcode (lcode);
3589 rcompcode = comparison_to_compcode (rcode);
3590 compcode = (code == TRUTH_AND_EXPR)
3591 ? lcompcode & rcompcode
3592 : lcompcode | rcompcode;
3597 if (compcode == COMPCODE_TRUE)
3598 return convert (truth_type, integer_one_node);
3599 else if (compcode == COMPCODE_FALSE)
3600 return convert (truth_type, integer_zero_node);
3601 else if (compcode != -1)
3602 return build (compcode_to_comparison (compcode),
3603 truth_type, ll_arg, lr_arg);
3606 /* If the RHS can be evaluated unconditionally and its operands are
3607 simple, it wins to evaluate the RHS unconditionally on machines
3608 with expensive branches. In this case, this isn't a comparison
3609 that can be merged. Avoid doing this if the RHS is a floating-point
3610 comparison since those can trap. */
3612 if (BRANCH_COST >= 2
3613 && ! FLOAT_TYPE_P (TREE_TYPE (rl_arg))
3614 && simple_operand_p (rl_arg)
3615 && simple_operand_p (rr_arg))
3617 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
3618 if (code == TRUTH_OR_EXPR
3619 && lcode == NE_EXPR && integer_zerop (lr_arg)
3620 && rcode == NE_EXPR && integer_zerop (rr_arg)
3621 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
3622 return build (NE_EXPR, truth_type,
3623 build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
3627 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
3628 if (code == TRUTH_AND_EXPR
3629 && lcode == EQ_EXPR && integer_zerop (lr_arg)
3630 && rcode == EQ_EXPR && integer_zerop (rr_arg)
3631 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
3632 return build (EQ_EXPR, truth_type,
3633 build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
3637 return build (code, truth_type, lhs, rhs);
3640 /* See if the comparisons can be merged. Then get all the parameters for
3643 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3644 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3648 ll_inner = decode_field_reference (ll_arg,
3649 &ll_bitsize, &ll_bitpos, &ll_mode,
3650 &ll_unsignedp, &volatilep, &ll_mask,
3652 lr_inner = decode_field_reference (lr_arg,
3653 &lr_bitsize, &lr_bitpos, &lr_mode,
3654 &lr_unsignedp, &volatilep, &lr_mask,
3656 rl_inner = decode_field_reference (rl_arg,
3657 &rl_bitsize, &rl_bitpos, &rl_mode,
3658 &rl_unsignedp, &volatilep, &rl_mask,
3660 rr_inner = decode_field_reference (rr_arg,
3661 &rr_bitsize, &rr_bitpos, &rr_mode,
3662 &rr_unsignedp, &volatilep, &rr_mask,
3665 /* It must be true that the inner operation on the lhs of each
3666 comparison must be the same if we are to be able to do anything.
3667 Then see if we have constants. If not, the same must be true for
3669 if (volatilep || ll_inner == 0 || rl_inner == 0
3670 || ! operand_equal_p (ll_inner, rl_inner, 0))
3673 if (TREE_CODE (lr_arg) == INTEGER_CST
3674 && TREE_CODE (rr_arg) == INTEGER_CST)
3675 l_const = lr_arg, r_const = rr_arg;
3676 else if (lr_inner == 0 || rr_inner == 0
3677 || ! operand_equal_p (lr_inner, rr_inner, 0))
3680 l_const = r_const = 0;
3682 /* If either comparison code is not correct for our logical operation,
3683 fail. However, we can convert a one-bit comparison against zero into
3684 the opposite comparison against that bit being set in the field. */
3686 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3687 if (lcode != wanted_code)
3689 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3691 /* Make the left operand unsigned, since we are only interested
3692 in the value of one bit. Otherwise we are doing the wrong
3701 /* This is analogous to the code for l_const above. */
3702 if (rcode != wanted_code)
3704 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3713 /* After this point all optimizations will generate bit-field
3714 references, which we might not want. */
3715 if (! (*lang_hooks.can_use_bit_fields_p) ())
3718 /* See if we can find a mode that contains both fields being compared on
3719 the left. If we can't, fail. Otherwise, update all constants and masks
3720 to be relative to a field of that size. */
3721 first_bit = MIN (ll_bitpos, rl_bitpos);
3722 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3723 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3724 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3726 if (lnmode == VOIDmode)
3729 lnbitsize = GET_MODE_BITSIZE (lnmode);
3730 lnbitpos = first_bit & ~ (lnbitsize - 1);
3731 lntype = (*lang_hooks.types.type_for_size) (lnbitsize, 1);
3732 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3734 if (BYTES_BIG_ENDIAN)
3736 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3737 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3740 ll_mask = const_binop (LSHIFT_EXPR, convert (lntype, ll_mask),
3741 size_int (xll_bitpos), 0);
3742 rl_mask = const_binop (LSHIFT_EXPR, convert (lntype, rl_mask),
3743 size_int (xrl_bitpos), 0);
3747 l_const = convert (lntype, l_const);
3748 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3749 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3750 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3751 fold (build1 (BIT_NOT_EXPR,
3755 warning ("comparison is always %d", wanted_code == NE_EXPR);
3757 return convert (truth_type,
3758 wanted_code == NE_EXPR
3759 ? integer_one_node : integer_zero_node);
3764 r_const = convert (lntype, r_const);
3765 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3766 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3767 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3768 fold (build1 (BIT_NOT_EXPR,
3772 warning ("comparison is always %d", wanted_code == NE_EXPR);
3774 return convert (truth_type,
3775 wanted_code == NE_EXPR
3776 ? integer_one_node : integer_zero_node);
3780 /* If the right sides are not constant, do the same for it. Also,
3781 disallow this optimization if a size or signedness mismatch occurs
3782 between the left and right sides. */
3785 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3786 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3787 /* Make sure the two fields on the right
3788 correspond to the left without being swapped. */
3789 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3792 first_bit = MIN (lr_bitpos, rr_bitpos);
3793 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3794 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3795 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3797 if (rnmode == VOIDmode)
3800 rnbitsize = GET_MODE_BITSIZE (rnmode);
3801 rnbitpos = first_bit & ~ (rnbitsize - 1);
3802 rntype = (*lang_hooks.types.type_for_size) (rnbitsize, 1);
3803 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3805 if (BYTES_BIG_ENDIAN)
3807 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3808 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3811 lr_mask = const_binop (LSHIFT_EXPR, convert (rntype, lr_mask),
3812 size_int (xlr_bitpos), 0);
3813 rr_mask = const_binop (LSHIFT_EXPR, convert (rntype, rr_mask),
3814 size_int (xrr_bitpos), 0);
3816 /* Make a mask that corresponds to both fields being compared.
3817 Do this for both items being compared. If the operands are the
3818 same size and the bits being compared are in the same position
3819 then we can do this by masking both and comparing the masked
3821 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3822 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3823 if (lnbitsize == rnbitsize && xll_bitpos == xlr_bitpos)
3825 lhs = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
3826 ll_unsignedp || rl_unsignedp);
3827 if (! all_ones_mask_p (ll_mask, lnbitsize))
3828 lhs = build (BIT_AND_EXPR, lntype, lhs, ll_mask);
3830 rhs = make_bit_field_ref (lr_inner, rntype, rnbitsize, rnbitpos,
3831 lr_unsignedp || rr_unsignedp);
3832 if (! all_ones_mask_p (lr_mask, rnbitsize))
3833 rhs = build (BIT_AND_EXPR, rntype, rhs, lr_mask);
3835 return build (wanted_code, truth_type, lhs, rhs);
3838 /* There is still another way we can do something: If both pairs of
3839 fields being compared are adjacent, we may be able to make a wider
3840 field containing them both.
3842 Note that we still must mask the lhs/rhs expressions. Furthermore,
3843 the mask must be shifted to account for the shift done by
3844 make_bit_field_ref. */
3845 if ((ll_bitsize + ll_bitpos == rl_bitpos
3846 && lr_bitsize + lr_bitpos == rr_bitpos)
3847 || (ll_bitpos == rl_bitpos + rl_bitsize
3848 && lr_bitpos == rr_bitpos + rr_bitsize))
3852 lhs = make_bit_field_ref (ll_inner, lntype, ll_bitsize + rl_bitsize,
3853 MIN (ll_bitpos, rl_bitpos), ll_unsignedp);
3854 rhs = make_bit_field_ref (lr_inner, rntype, lr_bitsize + rr_bitsize,
3855 MIN (lr_bitpos, rr_bitpos), lr_unsignedp);
3857 ll_mask = const_binop (RSHIFT_EXPR, ll_mask,
3858 size_int (MIN (xll_bitpos, xrl_bitpos)), 0);
3859 lr_mask = const_binop (RSHIFT_EXPR, lr_mask,
3860 size_int (MIN (xlr_bitpos, xrr_bitpos)), 0);
3862 /* Convert to the smaller type before masking out unwanted bits. */
3864 if (lntype != rntype)
3866 if (lnbitsize > rnbitsize)
3868 lhs = convert (rntype, lhs);
3869 ll_mask = convert (rntype, ll_mask);
3872 else if (lnbitsize < rnbitsize)
3874 rhs = convert (lntype, rhs);
3875 lr_mask = convert (lntype, lr_mask);
3880 if (! all_ones_mask_p (ll_mask, ll_bitsize + rl_bitsize))
3881 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3883 if (! all_ones_mask_p (lr_mask, lr_bitsize + rr_bitsize))
3884 rhs = build (BIT_AND_EXPR, type, rhs, lr_mask);
3886 return build (wanted_code, truth_type, lhs, rhs);
3892 /* Handle the case of comparisons with constants. If there is something in
3893 common between the masks, those bits of the constants must be the same.
3894 If not, the condition is always false. Test for this to avoid generating
3895 incorrect code below. */
3896 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3897 if (! integer_zerop (result)
3898 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3899 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3901 if (wanted_code == NE_EXPR)
3903 warning ("`or' of unmatched not-equal tests is always 1");
3904 return convert (truth_type, integer_one_node);
3908 warning ("`and' of mutually exclusive equal-tests is always 0");
3909 return convert (truth_type, integer_zero_node);
3913 /* Construct the expression we will return. First get the component
3914 reference we will make. Unless the mask is all ones the width of
3915 that field, perform the mask operation. Then compare with the
3917 result = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
3918 ll_unsignedp || rl_unsignedp);
3920 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3921 if (! all_ones_mask_p (ll_mask, lnbitsize))
3922 result = build (BIT_AND_EXPR, lntype, result, ll_mask);
3924 return build (wanted_code, truth_type, result,
3925 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3928 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
3932 optimize_minmax_comparison (t)
3935 tree type = TREE_TYPE (t);
3936 tree arg0 = TREE_OPERAND (t, 0);
3937 enum tree_code op_code;
3938 tree comp_const = TREE_OPERAND (t, 1);
3940 int consts_equal, consts_lt;
3943 STRIP_SIGN_NOPS (arg0);
3945 op_code = TREE_CODE (arg0);
3946 minmax_const = TREE_OPERAND (arg0, 1);
3947 consts_equal = tree_int_cst_equal (minmax_const, comp_const);
3948 consts_lt = tree_int_cst_lt (minmax_const, comp_const);
3949 inner = TREE_OPERAND (arg0, 0);
3951 /* If something does not permit us to optimize, return the original tree. */
3952 if ((op_code != MIN_EXPR && op_code != MAX_EXPR)
3953 || TREE_CODE (comp_const) != INTEGER_CST
3954 || TREE_CONSTANT_OVERFLOW (comp_const)
3955 || TREE_CODE (minmax_const) != INTEGER_CST
3956 || TREE_CONSTANT_OVERFLOW (minmax_const))
3959 /* Now handle all the various comparison codes. We only handle EQ_EXPR
3960 and GT_EXPR, doing the rest with recursive calls using logical
3962 switch (TREE_CODE (t))
3964 case NE_EXPR: case LT_EXPR: case LE_EXPR:
3966 invert_truthvalue (optimize_minmax_comparison (invert_truthvalue (t)));
3970 fold (build (TRUTH_ORIF_EXPR, type,
3971 optimize_minmax_comparison
3972 (build (EQ_EXPR, type, arg0, comp_const)),
3973 optimize_minmax_comparison
3974 (build (GT_EXPR, type, arg0, comp_const))));
3977 if (op_code == MAX_EXPR && consts_equal)
3978 /* MAX (X, 0) == 0 -> X <= 0 */
3979 return fold (build (LE_EXPR, type, inner, comp_const));
3981 else if (op_code == MAX_EXPR && consts_lt)
3982 /* MAX (X, 0) == 5 -> X == 5 */
3983 return fold (build (EQ_EXPR, type, inner, comp_const));
3985 else if (op_code == MAX_EXPR)
3986 /* MAX (X, 0) == -1 -> false */
3987 return omit_one_operand (type, integer_zero_node, inner);
3989 else if (consts_equal)
3990 /* MIN (X, 0) == 0 -> X >= 0 */
3991 return fold (build (GE_EXPR, type, inner, comp_const));
3994 /* MIN (X, 0) == 5 -> false */
3995 return omit_one_operand (type, integer_zero_node, inner);
3998 /* MIN (X, 0) == -1 -> X == -1 */
3999 return fold (build (EQ_EXPR, type, inner, comp_const));
4002 if (op_code == MAX_EXPR && (consts_equal || consts_lt))
4003 /* MAX (X, 0) > 0 -> X > 0
4004 MAX (X, 0) > 5 -> X > 5 */
4005 return fold (build (GT_EXPR, type, inner, comp_const));
4007 else if (op_code == MAX_EXPR)
4008 /* MAX (X, 0) > -1 -> true */
4009 return omit_one_operand (type, integer_one_node, inner);
4011 else if (op_code == MIN_EXPR && (consts_equal || consts_lt))
4012 /* MIN (X, 0) > 0 -> false
4013 MIN (X, 0) > 5 -> false */
4014 return omit_one_operand (type, integer_zero_node, inner);
4017 /* MIN (X, 0) > -1 -> X > -1 */
4018 return fold (build (GT_EXPR, type, inner, comp_const));
4025 /* T is an integer expression that is being multiplied, divided, or taken a
4026 modulus (CODE says which and what kind of divide or modulus) by a
4027 constant C. See if we can eliminate that operation by folding it with
4028 other operations already in T. WIDE_TYPE, if non-null, is a type that
4029 should be used for the computation if wider than our type.
4031 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
4032 (X * 2) + (Y * 4). We must, however, be assured that either the original
4033 expression would not overflow or that overflow is undefined for the type
4034 in the language in question.
4036 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
4037 the machine has a multiply-accumulate insn or that this is part of an
4038 addressing calculation.
4040 If we return a non-null expression, it is an equivalent form of the
4041 original computation, but need not be in the original type. */
4044 extract_muldiv (t, c, code, wide_type)
4047 enum tree_code code;
4050 /* To avoid exponential search depth, refuse to allow recursion past
4051 three levels. Beyond that (1) it's highly unlikely that we'll find
4052 something interesting and (2) we've probably processed it before
4053 when we built the inner expression. */
4062 ret = extract_muldiv_1 (t, c, code, wide_type);
4069 extract_muldiv_1 (t, c, code, wide_type)
4072 enum tree_code code;
4075 tree type = TREE_TYPE (t);
4076 enum tree_code tcode = TREE_CODE (t);
4077 tree ctype = (wide_type != 0 && (GET_MODE_SIZE (TYPE_MODE (wide_type))
4078 > GET_MODE_SIZE (TYPE_MODE (type)))
4079 ? wide_type : type);
4081 int same_p = tcode == code;
4082 tree op0 = NULL_TREE, op1 = NULL_TREE;
4084 /* Don't deal with constants of zero here; they confuse the code below. */
4085 if (integer_zerop (c))
4088 if (TREE_CODE_CLASS (tcode) == '1')
4089 op0 = TREE_OPERAND (t, 0);
4091 if (TREE_CODE_CLASS (tcode) == '2')
4092 op0 = TREE_OPERAND (t, 0), op1 = TREE_OPERAND (t, 1);
4094 /* Note that we need not handle conditional operations here since fold
4095 already handles those cases. So just do arithmetic here. */
4099 /* For a constant, we can always simplify if we are a multiply
4100 or (for divide and modulus) if it is a multiple of our constant. */
4101 if (code == MULT_EXPR
4102 || integer_zerop (const_binop (TRUNC_MOD_EXPR, t, c, 0)))
4103 return const_binop (code, convert (ctype, t), convert (ctype, c), 0);
4106 case CONVERT_EXPR: case NON_LVALUE_EXPR: case NOP_EXPR:
4107 /* If op0 is an expression ... */
4108 if ((TREE_CODE_CLASS (TREE_CODE (op0)) == '<'
4109 || TREE_CODE_CLASS (TREE_CODE (op0)) == '1'
4110 || TREE_CODE_CLASS (TREE_CODE (op0)) == '2'
4111 || TREE_CODE_CLASS (TREE_CODE (op0)) == 'e')
4112 /* ... and is unsigned, and its type is smaller than ctype,
4113 then we cannot pass through as widening. */
4114 && ((TREE_UNSIGNED (TREE_TYPE (op0))
4115 && ! (TREE_CODE (TREE_TYPE (op0)) == INTEGER_TYPE
4116 && TYPE_IS_SIZETYPE (TREE_TYPE (op0)))
4117 && (GET_MODE_SIZE (TYPE_MODE (ctype))
4118 > GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0)))))
4119 /* ... or its type is larger than ctype,
4120 then we cannot pass through this truncation. */
4121 || (GET_MODE_SIZE (TYPE_MODE (ctype))
4122 < GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))))
4125 /* Pass the constant down and see if we can make a simplification. If
4126 we can, replace this expression with the inner simplification for
4127 possible later conversion to our or some other type. */
4128 if (0 != (t1 = extract_muldiv (op0, convert (TREE_TYPE (op0), c), code,
4129 code == MULT_EXPR ? ctype : NULL_TREE)))
4133 case NEGATE_EXPR: case ABS_EXPR:
4134 if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
4135 return fold (build1 (tcode, ctype, convert (ctype, t1)));
4138 case MIN_EXPR: case MAX_EXPR:
4139 /* If widening the type changes the signedness, then we can't perform
4140 this optimization as that changes the result. */
4141 if (TREE_UNSIGNED (ctype) != TREE_UNSIGNED (type))
4144 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
4145 if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0
4146 && (t2 = extract_muldiv (op1, c, code, wide_type)) != 0)
4148 if (tree_int_cst_sgn (c) < 0)
4149 tcode = (tcode == MIN_EXPR ? MAX_EXPR : MIN_EXPR);
4151 return fold (build (tcode, ctype, convert (ctype, t1),
4152 convert (ctype, t2)));
4156 case WITH_RECORD_EXPR:
4157 if ((t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code, wide_type)) != 0)
4158 return build (WITH_RECORD_EXPR, TREE_TYPE (t1), t1,
4159 TREE_OPERAND (t, 1));
4163 /* If this has not been evaluated and the operand has no side effects,
4164 we can see if we can do something inside it and make a new one.
4165 Note that this test is overly conservative since we can do this
4166 if the only reason it had side effects is that it was another
4167 similar SAVE_EXPR, but that isn't worth bothering with. */
4168 if (SAVE_EXPR_RTL (t) == 0 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0))
4169 && 0 != (t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code,
4172 t1 = save_expr (t1);
4173 if (SAVE_EXPR_PERSISTENT_P (t) && TREE_CODE (t1) == SAVE_EXPR)
4174 SAVE_EXPR_PERSISTENT_P (t1) = 1;
4175 if (is_pending_size (t))
4176 put_pending_size (t1);
4181 case LSHIFT_EXPR: case RSHIFT_EXPR:
4182 /* If the second operand is constant, this is a multiplication
4183 or floor division, by a power of two, so we can treat it that
4184 way unless the multiplier or divisor overflows. */
4185 if (TREE_CODE (op1) == INTEGER_CST
4186 /* const_binop may not detect overflow correctly,
4187 so check for it explicitly here. */
4188 && TYPE_PRECISION (TREE_TYPE (size_one_node)) > TREE_INT_CST_LOW (op1)
4189 && TREE_INT_CST_HIGH (op1) == 0
4190 && 0 != (t1 = convert (ctype,
4191 const_binop (LSHIFT_EXPR, size_one_node,
4193 && ! TREE_OVERFLOW (t1))
4194 return extract_muldiv (build (tcode == LSHIFT_EXPR
4195 ? MULT_EXPR : FLOOR_DIV_EXPR,
4196 ctype, convert (ctype, op0), t1),
4197 c, code, wide_type);
4200 case PLUS_EXPR: case MINUS_EXPR:
4201 /* See if we can eliminate the operation on both sides. If we can, we
4202 can return a new PLUS or MINUS. If we can't, the only remaining
4203 cases where we can do anything are if the second operand is a
4205 t1 = extract_muldiv (op0, c, code, wide_type);
4206 t2 = extract_muldiv (op1, c, code, wide_type);
4207 if (t1 != 0 && t2 != 0
4208 && (code == MULT_EXPR
4209 /* If not multiplication, we can only do this if both operands
4210 are divisible by c. */
4211 || (multiple_of_p (ctype, op0, c)
4212 && multiple_of_p (ctype, op1, c))))
4213 return fold (build (tcode, ctype, convert (ctype, t1),
4214 convert (ctype, t2)));
4216 /* If this was a subtraction, negate OP1 and set it to be an addition.
4217 This simplifies the logic below. */
4218 if (tcode == MINUS_EXPR)
4219 tcode = PLUS_EXPR, op1 = negate_expr (op1);
4221 if (TREE_CODE (op1) != INTEGER_CST)
4224 /* If either OP1 or C are negative, this optimization is not safe for
4225 some of the division and remainder types while for others we need
4226 to change the code. */
4227 if (tree_int_cst_sgn (op1) < 0 || tree_int_cst_sgn (c) < 0)
4229 if (code == CEIL_DIV_EXPR)
4230 code = FLOOR_DIV_EXPR;
4231 else if (code == FLOOR_DIV_EXPR)
4232 code = CEIL_DIV_EXPR;
4233 else if (code != MULT_EXPR
4234 && code != CEIL_MOD_EXPR && code != FLOOR_MOD_EXPR)
4238 /* If it's a multiply or a division/modulus operation of a multiple
4239 of our constant, do the operation and verify it doesn't overflow. */
4240 if (code == MULT_EXPR
4241 || integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4243 op1 = const_binop (code, convert (ctype, op1), convert (ctype, c), 0);
4244 if (op1 == 0 || TREE_OVERFLOW (op1))
4250 /* If we have an unsigned type is not a sizetype, we cannot widen
4251 the operation since it will change the result if the original
4252 computation overflowed. */
4253 if (TREE_UNSIGNED (ctype)
4254 && ! (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype))
4258 /* If we were able to eliminate our operation from the first side,
4259 apply our operation to the second side and reform the PLUS. */
4260 if (t1 != 0 && (TREE_CODE (t1) != code || code == MULT_EXPR))
4261 return fold (build (tcode, ctype, convert (ctype, t1), op1));
4263 /* The last case is if we are a multiply. In that case, we can
4264 apply the distributive law to commute the multiply and addition
4265 if the multiplication of the constants doesn't overflow. */
4266 if (code == MULT_EXPR)
4267 return fold (build (tcode, ctype, fold (build (code, ctype,
4268 convert (ctype, op0),
4269 convert (ctype, c))),
4275 /* We have a special case here if we are doing something like
4276 (C * 8) % 4 since we know that's zero. */
4277 if ((code == TRUNC_MOD_EXPR || code == CEIL_MOD_EXPR
4278 || code == FLOOR_MOD_EXPR || code == ROUND_MOD_EXPR)
4279 && TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST
4280 && integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4281 return omit_one_operand (type, integer_zero_node, op0);
4283 /* Arrange for the code below to simplify two constants first. */
4284 if (TREE_CODE (op1) == INTEGER_CST && TREE_CODE (op0) != INTEGER_CST)
4291 /* ... fall through ... */
4293 case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR:
4294 case ROUND_DIV_EXPR: case EXACT_DIV_EXPR:
4295 /* If we can extract our operation from the LHS, do so and return a
4296 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
4297 do something only if the second operand is a constant. */
4299 && (t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
4300 return fold (build (tcode, ctype, convert (ctype, t1),
4301 convert (ctype, op1)));
4302 else if (tcode == MULT_EXPR && code == MULT_EXPR
4303 && (t1 = extract_muldiv (op1, c, code, wide_type)) != 0)
4304 return fold (build (tcode, ctype, convert (ctype, op0),
4305 convert (ctype, t1)));
4306 else if (TREE_CODE (op1) != INTEGER_CST)
4309 /* If these are the same operation types, we can associate them
4310 assuming no overflow. */
4312 && 0 != (t1 = const_binop (MULT_EXPR, convert (ctype, op1),
4313 convert (ctype, c), 0))
4314 && ! TREE_OVERFLOW (t1))
4315 return fold (build (tcode, ctype, convert (ctype, op0), t1));
4317 /* If these operations "cancel" each other, we have the main
4318 optimizations of this pass, which occur when either constant is a
4319 multiple of the other, in which case we replace this with either an
4320 operation or CODE or TCODE.
4322 If we have an unsigned type that is not a sizetype, we cannot do
4323 this since it will change the result if the original computation
4325 if ((! TREE_UNSIGNED (ctype)
4326 || (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype)))
4327 && ((code == MULT_EXPR && tcode == EXACT_DIV_EXPR)
4328 || (tcode == MULT_EXPR
4329 && code != TRUNC_MOD_EXPR && code != CEIL_MOD_EXPR
4330 && code != FLOOR_MOD_EXPR && code != ROUND_MOD_EXPR)))
4332 if (integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4333 return fold (build (tcode, ctype, convert (ctype, op0),
4335 const_binop (TRUNC_DIV_EXPR,
4337 else if (integer_zerop (const_binop (TRUNC_MOD_EXPR, c, op1, 0)))
4338 return fold (build (code, ctype, convert (ctype, op0),
4340 const_binop (TRUNC_DIV_EXPR,
4352 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
4353 S, a SAVE_EXPR, return the expression actually being evaluated. Note
4354 that we may sometimes modify the tree. */
4357 strip_compound_expr (t, s)
4361 enum tree_code code = TREE_CODE (t);
4363 /* See if this is the COMPOUND_EXPR we want to eliminate. */
4364 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
4365 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
4366 return TREE_OPERAND (t, 1);
4368 /* See if this is a COND_EXPR or a simple arithmetic operator. We
4369 don't bother handling any other types. */
4370 else if (code == COND_EXPR)
4372 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4373 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4374 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
4376 else if (TREE_CODE_CLASS (code) == '1')
4377 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4378 else if (TREE_CODE_CLASS (code) == '<'
4379 || TREE_CODE_CLASS (code) == '2')
4381 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4382 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4388 /* Return a node which has the indicated constant VALUE (either 0 or
4389 1), and is of the indicated TYPE. */
4392 constant_boolean_node (value, type)
4396 if (type == integer_type_node)
4397 return value ? integer_one_node : integer_zero_node;
4398 else if (TREE_CODE (type) == BOOLEAN_TYPE)
4399 return (*lang_hooks.truthvalue_conversion) (value ? integer_one_node :
4403 tree t = build_int_2 (value, 0);
4405 TREE_TYPE (t) = type;
4410 /* Utility function for the following routine, to see how complex a nesting of
4411 COND_EXPRs can be. EXPR is the expression and LIMIT is a count beyond which
4412 we don't care (to avoid spending too much time on complex expressions.). */
4415 count_cond (expr, lim)
4421 if (TREE_CODE (expr) != COND_EXPR)
4426 ctrue = count_cond (TREE_OPERAND (expr, 1), lim - 1);
4427 cfalse = count_cond (TREE_OPERAND (expr, 2), lim - 1 - ctrue);
4428 return MIN (lim, 1 + ctrue + cfalse);
4431 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
4432 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
4433 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
4434 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
4435 COND is the first argument to CODE; otherwise (as in the example
4436 given here), it is the second argument. TYPE is the type of the
4437 original expression. */
4440 fold_binary_op_with_conditional_arg (code, type, cond, arg, cond_first_p)
4441 enum tree_code code;
4447 tree test, true_value, false_value;
4448 tree lhs = NULL_TREE;
4449 tree rhs = NULL_TREE;
4450 /* In the end, we'll produce a COND_EXPR. Both arms of the
4451 conditional expression will be binary operations. The left-hand
4452 side of the expression to be executed if the condition is true
4453 will be pointed to by TRUE_LHS. Similarly, the right-hand side
4454 of the expression to be executed if the condition is true will be
4455 pointed to by TRUE_RHS. FALSE_LHS and FALSE_RHS are analogous --
4456 but apply to the expression to be executed if the conditional is
4462 /* These are the codes to use for the left-hand side and right-hand
4463 side of the COND_EXPR. Normally, they are the same as CODE. */
4464 enum tree_code lhs_code = code;
4465 enum tree_code rhs_code = code;
4466 /* And these are the types of the expressions. */
4467 tree lhs_type = type;
4468 tree rhs_type = type;
4473 true_rhs = false_rhs = &arg;
4474 true_lhs = &true_value;
4475 false_lhs = &false_value;
4479 true_lhs = false_lhs = &arg;
4480 true_rhs = &true_value;
4481 false_rhs = &false_value;
4484 if (TREE_CODE (cond) == COND_EXPR)
4486 test = TREE_OPERAND (cond, 0);
4487 true_value = TREE_OPERAND (cond, 1);
4488 false_value = TREE_OPERAND (cond, 2);
4489 /* If this operand throws an expression, then it does not make
4490 sense to try to perform a logical or arithmetic operation
4491 involving it. Instead of building `a + throw 3' for example,
4492 we simply build `a, throw 3'. */
4493 if (VOID_TYPE_P (TREE_TYPE (true_value)))
4497 lhs_code = COMPOUND_EXPR;
4498 lhs_type = void_type_node;
4503 if (VOID_TYPE_P (TREE_TYPE (false_value)))
4507 rhs_code = COMPOUND_EXPR;
4508 rhs_type = void_type_node;
4516 tree testtype = TREE_TYPE (cond);
4518 true_value = convert (testtype, integer_one_node);
4519 false_value = convert (testtype, integer_zero_node);
4522 /* If ARG is complex we want to make sure we only evaluate
4523 it once. Though this is only required if it is volatile, it
4524 might be more efficient even if it is not. However, if we
4525 succeed in folding one part to a constant, we do not need
4526 to make this SAVE_EXPR. Since we do this optimization
4527 primarily to see if we do end up with constant and this
4528 SAVE_EXPR interferes with later optimizations, suppressing
4529 it when we can is important.
4531 If we are not in a function, we can't make a SAVE_EXPR, so don't
4532 try to do so. Don't try to see if the result is a constant
4533 if an arm is a COND_EXPR since we get exponential behavior
4536 if (TREE_CODE (arg) == SAVE_EXPR)
4538 else if (lhs == 0 && rhs == 0
4539 && !TREE_CONSTANT (arg)
4540 && (*lang_hooks.decls.global_bindings_p) () == 0
4541 && ((TREE_CODE (arg) != VAR_DECL && TREE_CODE (arg) != PARM_DECL)
4542 || TREE_SIDE_EFFECTS (arg)))
4544 if (TREE_CODE (true_value) != COND_EXPR)
4545 lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
4547 if (TREE_CODE (false_value) != COND_EXPR)
4548 rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
4550 if ((lhs == 0 || ! TREE_CONSTANT (lhs))
4551 && (rhs == 0 || !TREE_CONSTANT (rhs)))
4553 arg = save_expr (arg);
4560 lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
4562 rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
4564 test = fold (build (COND_EXPR, type, test, lhs, rhs));
4567 return build (COMPOUND_EXPR, type,
4568 convert (void_type_node, arg),
4569 strip_compound_expr (test, arg));
4571 return convert (type, test);
4575 /* Subroutine of fold() that checks for the addition of +/- 0.0.
4577 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
4578 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
4579 ADDEND is the same as X.
4581 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
4582 and finite. The problematic cases are when X is zero, and its mode
4583 has signed zeros. In the case of rounding towards -infinity,
4584 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
4585 modes, X + 0 is not the same as X because -0 + 0 is 0. */
4588 fold_real_zero_addition_p (type, addend, negate)
4592 if (!real_zerop (addend))
4595 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
4596 if (!HONOR_SIGNED_ZEROS (TYPE_MODE (type)))
4599 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
4600 if (TREE_CODE (addend) == REAL_CST
4601 && REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (addend)))
4604 /* The mode has signed zeros, and we have to honor their sign.
4605 In this situation, there is only one case we can return true for.
4606 X - 0 is the same as X unless rounding towards -infinity is
4608 return negate && !HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (type));
4612 /* Perform constant folding and related simplification of EXPR.
4613 The related simplifications include x*1 => x, x*0 => 0, etc.,
4614 and application of the associative law.
4615 NOP_EXPR conversions may be removed freely (as long as we
4616 are careful not to change the C type of the overall expression)
4617 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
4618 but we can constant-fold them if they have constant operands. */
4625 tree t1 = NULL_TREE;
4627 tree type = TREE_TYPE (expr);
4628 tree arg0 = NULL_TREE, arg1 = NULL_TREE;
4629 enum tree_code code = TREE_CODE (t);
4630 int kind = TREE_CODE_CLASS (code);
4632 /* WINS will be nonzero when the switch is done
4633 if all operands are constant. */
4636 /* Don't try to process an RTL_EXPR since its operands aren't trees.
4637 Likewise for a SAVE_EXPR that's already been evaluated. */
4638 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t) != 0))
4641 /* Return right away if a constant. */
4645 #ifdef MAX_INTEGER_COMPUTATION_MODE
4646 check_max_integer_computation_mode (expr);
4649 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
4653 /* Special case for conversion ops that can have fixed point args. */
4654 arg0 = TREE_OPERAND (t, 0);
4656 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
4658 STRIP_SIGN_NOPS (arg0);
4660 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
4661 subop = TREE_REALPART (arg0);
4665 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
4666 && TREE_CODE (subop) != REAL_CST
4668 /* Note that TREE_CONSTANT isn't enough:
4669 static var addresses are constant but we can't
4670 do arithmetic on them. */
4673 else if (IS_EXPR_CODE_CLASS (kind) || kind == 'r')
4675 int len = first_rtl_op (code);
4677 for (i = 0; i < len; i++)
4679 tree op = TREE_OPERAND (t, i);
4683 continue; /* Valid for CALL_EXPR, at least. */
4685 if (kind == '<' || code == RSHIFT_EXPR)
4687 /* Signedness matters here. Perhaps we can refine this
4689 STRIP_SIGN_NOPS (op);
4692 /* Strip any conversions that don't change the mode. */
4695 if (TREE_CODE (op) == COMPLEX_CST)
4696 subop = TREE_REALPART (op);
4700 if (TREE_CODE (subop) != INTEGER_CST
4701 && TREE_CODE (subop) != REAL_CST)
4702 /* Note that TREE_CONSTANT isn't enough:
4703 static var addresses are constant but we can't
4704 do arithmetic on them. */
4714 /* If this is a commutative operation, and ARG0 is a constant, move it
4715 to ARG1 to reduce the number of tests below. */
4716 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
4717 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
4718 || code == BIT_AND_EXPR)
4719 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
4721 tem = arg0; arg0 = arg1; arg1 = tem;
4723 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
4724 TREE_OPERAND (t, 1) = tem;
4727 /* Now WINS is set as described above,
4728 ARG0 is the first operand of EXPR,
4729 and ARG1 is the second operand (if it has more than one operand).
4731 First check for cases where an arithmetic operation is applied to a
4732 compound, conditional, or comparison operation. Push the arithmetic
4733 operation inside the compound or conditional to see if any folding
4734 can then be done. Convert comparison to conditional for this purpose.
4735 The also optimizes non-constant cases that used to be done in
4738 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
4739 one of the operands is a comparison and the other is a comparison, a
4740 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
4741 code below would make the expression more complex. Change it to a
4742 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
4743 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
4745 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
4746 || code == EQ_EXPR || code == NE_EXPR)
4747 && ((truth_value_p (TREE_CODE (arg0))
4748 && (truth_value_p (TREE_CODE (arg1))
4749 || (TREE_CODE (arg1) == BIT_AND_EXPR
4750 && integer_onep (TREE_OPERAND (arg1, 1)))))
4751 || (truth_value_p (TREE_CODE (arg1))
4752 && (truth_value_p (TREE_CODE (arg0))
4753 || (TREE_CODE (arg0) == BIT_AND_EXPR
4754 && integer_onep (TREE_OPERAND (arg0, 1)))))))
4756 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
4757 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
4761 if (code == EQ_EXPR)
4762 t = invert_truthvalue (t);
4767 if (TREE_CODE_CLASS (code) == '1')
4769 if (TREE_CODE (arg0) == COMPOUND_EXPR)
4770 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4771 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
4772 else if (TREE_CODE (arg0) == COND_EXPR)
4774 tree arg01 = TREE_OPERAND (arg0, 1);
4775 tree arg02 = TREE_OPERAND (arg0, 2);
4776 if (! VOID_TYPE_P (TREE_TYPE (arg01)))
4777 arg01 = fold (build1 (code, type, arg01));
4778 if (! VOID_TYPE_P (TREE_TYPE (arg02)))
4779 arg02 = fold (build1 (code, type, arg02));
4780 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
4783 /* If this was a conversion, and all we did was to move into
4784 inside the COND_EXPR, bring it back out. But leave it if
4785 it is a conversion from integer to integer and the
4786 result precision is no wider than a word since such a
4787 conversion is cheap and may be optimized away by combine,
4788 while it couldn't if it were outside the COND_EXPR. Then return
4789 so we don't get into an infinite recursion loop taking the
4790 conversion out and then back in. */
4792 if ((code == NOP_EXPR || code == CONVERT_EXPR
4793 || code == NON_LVALUE_EXPR)
4794 && TREE_CODE (t) == COND_EXPR
4795 && TREE_CODE (TREE_OPERAND (t, 1)) == code
4796 && TREE_CODE (TREE_OPERAND (t, 2)) == code
4797 && ! VOID_TYPE_P (TREE_OPERAND (t, 1))
4798 && ! VOID_TYPE_P (TREE_OPERAND (t, 2))
4799 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
4800 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
4801 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
4803 (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))))
4804 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
4805 t = build1 (code, type,
4807 TREE_TYPE (TREE_OPERAND
4808 (TREE_OPERAND (t, 1), 0)),
4809 TREE_OPERAND (t, 0),
4810 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
4811 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
4814 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
4815 return fold (build (COND_EXPR, type, arg0,
4816 fold (build1 (code, type, integer_one_node)),
4817 fold (build1 (code, type, integer_zero_node))));
4819 else if (TREE_CODE_CLASS (code) == '2'
4820 || TREE_CODE_CLASS (code) == '<')
4822 if (TREE_CODE (arg1) == COMPOUND_EXPR
4823 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg1, 0))
4824 && ! TREE_SIDE_EFFECTS (arg0))
4825 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4826 fold (build (code, type,
4827 arg0, TREE_OPERAND (arg1, 1))));
4828 else if ((TREE_CODE (arg1) == COND_EXPR
4829 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
4830 && TREE_CODE_CLASS (code) != '<'))
4831 && (TREE_CODE (arg0) != COND_EXPR
4832 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4833 && (! TREE_SIDE_EFFECTS (arg0)
4834 || ((*lang_hooks.decls.global_bindings_p) () == 0
4835 && ! contains_placeholder_p (arg0))))
4837 fold_binary_op_with_conditional_arg (code, type, arg1, arg0,
4838 /*cond_first_p=*/0);
4839 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
4840 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4841 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4842 else if ((TREE_CODE (arg0) == COND_EXPR
4843 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4844 && TREE_CODE_CLASS (code) != '<'))
4845 && (TREE_CODE (arg1) != COND_EXPR
4846 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4847 && (! TREE_SIDE_EFFECTS (arg1)
4848 || ((*lang_hooks.decls.global_bindings_p) () == 0
4849 && ! contains_placeholder_p (arg1))))
4851 fold_binary_op_with_conditional_arg (code, type, arg0, arg1,
4852 /*cond_first_p=*/1);
4854 else if (TREE_CODE_CLASS (code) == '<'
4855 && TREE_CODE (arg0) == COMPOUND_EXPR)
4856 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4857 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4858 else if (TREE_CODE_CLASS (code) == '<'
4859 && TREE_CODE (arg1) == COMPOUND_EXPR)
4860 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4861 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4874 return fold (DECL_INITIAL (t));
4879 case FIX_TRUNC_EXPR:
4880 /* Other kinds of FIX are not handled properly by fold_convert. */
4882 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4883 return TREE_OPERAND (t, 0);
4885 /* Handle cases of two conversions in a row. */
4886 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4887 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4889 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4890 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4891 tree final_type = TREE_TYPE (t);
4892 int inside_int = INTEGRAL_TYPE_P (inside_type);
4893 int inside_ptr = POINTER_TYPE_P (inside_type);
4894 int inside_float = FLOAT_TYPE_P (inside_type);
4895 unsigned int inside_prec = TYPE_PRECISION (inside_type);
4896 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4897 int inter_int = INTEGRAL_TYPE_P (inter_type);
4898 int inter_ptr = POINTER_TYPE_P (inter_type);
4899 int inter_float = FLOAT_TYPE_P (inter_type);
4900 unsigned int inter_prec = TYPE_PRECISION (inter_type);
4901 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4902 int final_int = INTEGRAL_TYPE_P (final_type);
4903 int final_ptr = POINTER_TYPE_P (final_type);
4904 int final_float = FLOAT_TYPE_P (final_type);
4905 unsigned int final_prec = TYPE_PRECISION (final_type);
4906 int final_unsignedp = TREE_UNSIGNED (final_type);
4908 /* In addition to the cases of two conversions in a row
4909 handled below, if we are converting something to its own
4910 type via an object of identical or wider precision, neither
4911 conversion is needed. */
4912 if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (final_type)
4913 && ((inter_int && final_int) || (inter_float && final_float))
4914 && inter_prec >= final_prec)
4915 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4917 /* Likewise, if the intermediate and final types are either both
4918 float or both integer, we don't need the middle conversion if
4919 it is wider than the final type and doesn't change the signedness
4920 (for integers). Avoid this if the final type is a pointer
4921 since then we sometimes need the inner conversion. Likewise if
4922 the outer has a precision not equal to the size of its mode. */
4923 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4924 || (inter_float && inside_float))
4925 && inter_prec >= inside_prec
4926 && (inter_float || inter_unsignedp == inside_unsignedp)
4927 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4928 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4930 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4932 /* If we have a sign-extension of a zero-extended value, we can
4933 replace that by a single zero-extension. */
4934 if (inside_int && inter_int && final_int
4935 && inside_prec < inter_prec && inter_prec < final_prec
4936 && inside_unsignedp && !inter_unsignedp)
4937 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4939 /* Two conversions in a row are not needed unless:
4940 - some conversion is floating-point (overstrict for now), or
4941 - the intermediate type is narrower than both initial and
4943 - the intermediate type and innermost type differ in signedness,
4944 and the outermost type is wider than the intermediate, or
4945 - the initial type is a pointer type and the precisions of the
4946 intermediate and final types differ, or
4947 - the final type is a pointer type and the precisions of the
4948 initial and intermediate types differ. */
4949 if (! inside_float && ! inter_float && ! final_float
4950 && (inter_prec > inside_prec || inter_prec > final_prec)
4951 && ! (inside_int && inter_int
4952 && inter_unsignedp != inside_unsignedp
4953 && inter_prec < final_prec)
4954 && ((inter_unsignedp && inter_prec > inside_prec)
4955 == (final_unsignedp && final_prec > inter_prec))
4956 && ! (inside_ptr && inter_prec != final_prec)
4957 && ! (final_ptr && inside_prec != inter_prec)
4958 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4959 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4961 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4964 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4965 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4966 /* Detect assigning a bitfield. */
4967 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4968 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4970 /* Don't leave an assignment inside a conversion
4971 unless assigning a bitfield. */
4972 tree prev = TREE_OPERAND (t, 0);
4973 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4974 /* First do the assignment, then return converted constant. */
4975 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4980 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
4981 constants (if x has signed type, the sign bit cannot be set
4982 in c). This folds extension into the BIT_AND_EXPR. */
4983 if (INTEGRAL_TYPE_P (TREE_TYPE (t))
4984 && TREE_CODE (TREE_TYPE (t)) != BOOLEAN_TYPE
4985 && TREE_CODE (TREE_OPERAND (t, 0)) == BIT_AND_EXPR
4986 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 1)) == INTEGER_CST)
4988 tree and = TREE_OPERAND (t, 0);
4989 tree and0 = TREE_OPERAND (and, 0), and1 = TREE_OPERAND (and, 1);
4992 if (TREE_UNSIGNED (TREE_TYPE (and))
4993 || (TYPE_PRECISION (TREE_TYPE (t))
4994 <= TYPE_PRECISION (TREE_TYPE (and))))
4996 else if (TYPE_PRECISION (TREE_TYPE (and1))
4997 <= HOST_BITS_PER_WIDE_INT
4998 && host_integerp (and1, 1))
5000 unsigned HOST_WIDE_INT cst;
5002 cst = tree_low_cst (and1, 1);
5003 cst &= (HOST_WIDE_INT) -1
5004 << (TYPE_PRECISION (TREE_TYPE (and1)) - 1);
5005 change = (cst == 0);
5006 #ifdef LOAD_EXTEND_OP
5008 && (LOAD_EXTEND_OP (TYPE_MODE (TREE_TYPE (and0)))
5011 tree uns = (*lang_hooks.types.unsigned_type) (TREE_TYPE (and0));
5012 and0 = convert (uns, and0);
5013 and1 = convert (uns, and1);
5018 return fold (build (BIT_AND_EXPR, TREE_TYPE (t),
5019 convert (TREE_TYPE (t), and0),
5020 convert (TREE_TYPE (t), and1)));
5025 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
5028 return fold_convert (t, arg0);
5030 case VIEW_CONVERT_EXPR:
5031 if (TREE_CODE (TREE_OPERAND (t, 0)) == VIEW_CONVERT_EXPR)
5032 return build1 (VIEW_CONVERT_EXPR, type,
5033 TREE_OPERAND (TREE_OPERAND (t, 0), 0));
5037 if (TREE_CODE (arg0) == CONSTRUCTOR)
5039 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
5046 TREE_CONSTANT (t) = wins;
5052 if (TREE_CODE (arg0) == INTEGER_CST)
5054 unsigned HOST_WIDE_INT low;
5056 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
5057 TREE_INT_CST_HIGH (arg0),
5059 t = build_int_2 (low, high);
5060 TREE_TYPE (t) = type;
5062 = (TREE_OVERFLOW (arg0)
5063 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
5064 TREE_CONSTANT_OVERFLOW (t)
5065 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
5067 else if (TREE_CODE (arg0) == REAL_CST)
5068 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
5070 else if (TREE_CODE (arg0) == NEGATE_EXPR)
5071 return TREE_OPERAND (arg0, 0);
5072 /* Convert -((double)float) into (double)(-float). */
5073 else if (TREE_CODE (arg0) == NOP_EXPR
5074 && TREE_CODE (type) == REAL_TYPE)
5076 tree targ0 = strip_float_extensions (arg0);
5078 return convert (type, build1 (NEGATE_EXPR, TREE_TYPE (targ0), targ0));
5082 /* Convert - (a - b) to (b - a) for non-floating-point. */
5083 else if (TREE_CODE (arg0) == MINUS_EXPR
5084 && (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
5085 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
5086 TREE_OPERAND (arg0, 0));
5093 if (TREE_CODE (arg0) == INTEGER_CST)
5095 /* If the value is unsigned, then the absolute value is
5096 the same as the ordinary value. */
5097 if (TREE_UNSIGNED (type))
5099 /* Similarly, if the value is non-negative. */
5100 else if (INT_CST_LT (integer_minus_one_node, arg0))
5102 /* If the value is negative, then the absolute value is
5106 unsigned HOST_WIDE_INT low;
5108 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
5109 TREE_INT_CST_HIGH (arg0),
5111 t = build_int_2 (low, high);
5112 TREE_TYPE (t) = type;
5114 = (TREE_OVERFLOW (arg0)
5115 | force_fit_type (t, overflow));
5116 TREE_CONSTANT_OVERFLOW (t)
5117 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
5120 else if (TREE_CODE (arg0) == REAL_CST)
5122 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
5123 t = build_real (type,
5124 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
5127 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
5128 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
5129 /* Convert fabs((double)float) into (double)fabsf(float). */
5130 else if (TREE_CODE (arg0) == NOP_EXPR
5131 && TREE_CODE (type) == REAL_TYPE)
5133 tree targ0 = strip_float_extensions (arg0);
5135 return convert (type, build1 (ABS_EXPR, TREE_TYPE (targ0), targ0));
5140 /* fabs(sqrt(x)) = sqrt(x) and fabs(exp(x)) = exp(x). */
5141 enum built_in_function fcode = builtin_mathfn_code (arg0);
5142 if (fcode == BUILT_IN_SQRT
5143 || fcode == BUILT_IN_SQRTF
5144 || fcode == BUILT_IN_SQRTL
5145 || fcode == BUILT_IN_EXP
5146 || fcode == BUILT_IN_EXPF
5147 || fcode == BUILT_IN_EXPL)
5153 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5154 return convert (type, arg0);
5155 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5156 return build (COMPLEX_EXPR, type,
5157 TREE_OPERAND (arg0, 0),
5158 negate_expr (TREE_OPERAND (arg0, 1)));
5159 else if (TREE_CODE (arg0) == COMPLEX_CST)
5160 return build_complex (type, TREE_REALPART (arg0),
5161 negate_expr (TREE_IMAGPART (arg0)));
5162 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5163 return fold (build (TREE_CODE (arg0), type,
5164 fold (build1 (CONJ_EXPR, type,
5165 TREE_OPERAND (arg0, 0))),
5166 fold (build1 (CONJ_EXPR,
5167 type, TREE_OPERAND (arg0, 1)))));
5168 else if (TREE_CODE (arg0) == CONJ_EXPR)
5169 return TREE_OPERAND (arg0, 0);
5175 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
5176 ~ TREE_INT_CST_HIGH (arg0));
5177 TREE_TYPE (t) = type;
5178 force_fit_type (t, 0);
5179 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
5180 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
5182 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
5183 return TREE_OPERAND (arg0, 0);
5187 /* A + (-B) -> A - B */
5188 if (TREE_CODE (arg1) == NEGATE_EXPR)
5189 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
5190 /* (-A) + B -> B - A */
5191 if (TREE_CODE (arg0) == NEGATE_EXPR)
5192 return fold (build (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
5193 else if (! FLOAT_TYPE_P (type))
5195 if (integer_zerop (arg1))
5196 return non_lvalue (convert (type, arg0));
5198 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
5199 with a constant, and the two constants have no bits in common,
5200 we should treat this as a BIT_IOR_EXPR since this may produce more
5202 if (TREE_CODE (arg0) == BIT_AND_EXPR
5203 && TREE_CODE (arg1) == BIT_AND_EXPR
5204 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5205 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
5206 && integer_zerop (const_binop (BIT_AND_EXPR,
5207 TREE_OPERAND (arg0, 1),
5208 TREE_OPERAND (arg1, 1), 0)))
5210 code = BIT_IOR_EXPR;
5214 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
5215 (plus (plus (mult) (mult)) (foo)) so that we can
5216 take advantage of the factoring cases below. */
5217 if ((TREE_CODE (arg0) == PLUS_EXPR
5218 && TREE_CODE (arg1) == MULT_EXPR)
5219 || (TREE_CODE (arg1) == PLUS_EXPR
5220 && TREE_CODE (arg0) == MULT_EXPR))
5222 tree parg0, parg1, parg, marg;
5224 if (TREE_CODE (arg0) == PLUS_EXPR)
5225 parg = arg0, marg = arg1;
5227 parg = arg1, marg = arg0;
5228 parg0 = TREE_OPERAND (parg, 0);
5229 parg1 = TREE_OPERAND (parg, 1);
5233 if (TREE_CODE (parg0) == MULT_EXPR
5234 && TREE_CODE (parg1) != MULT_EXPR)
5235 return fold (build (PLUS_EXPR, type,
5236 fold (build (PLUS_EXPR, type, parg0, marg)),
5238 if (TREE_CODE (parg0) != MULT_EXPR
5239 && TREE_CODE (parg1) == MULT_EXPR)
5240 return fold (build (PLUS_EXPR, type,
5241 fold (build (PLUS_EXPR, type, parg1, marg)),
5245 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
5247 tree arg00, arg01, arg10, arg11;
5248 tree alt0 = NULL_TREE, alt1 = NULL_TREE, same;
5250 /* (A * C) + (B * C) -> (A+B) * C.
5251 We are most concerned about the case where C is a constant,
5252 but other combinations show up during loop reduction. Since
5253 it is not difficult, try all four possibilities. */
5255 arg00 = TREE_OPERAND (arg0, 0);
5256 arg01 = TREE_OPERAND (arg0, 1);
5257 arg10 = TREE_OPERAND (arg1, 0);
5258 arg11 = TREE_OPERAND (arg1, 1);
5261 if (operand_equal_p (arg01, arg11, 0))
5262 same = arg01, alt0 = arg00, alt1 = arg10;
5263 else if (operand_equal_p (arg00, arg10, 0))
5264 same = arg00, alt0 = arg01, alt1 = arg11;
5265 else if (operand_equal_p (arg00, arg11, 0))
5266 same = arg00, alt0 = arg01, alt1 = arg10;
5267 else if (operand_equal_p (arg01, arg10, 0))
5268 same = arg01, alt0 = arg00, alt1 = arg11;
5270 /* No identical multiplicands; see if we can find a common
5271 power-of-two factor in non-power-of-two multiplies. This
5272 can help in multi-dimensional array access. */
5273 else if (TREE_CODE (arg01) == INTEGER_CST
5274 && TREE_CODE (arg11) == INTEGER_CST
5275 && TREE_INT_CST_HIGH (arg01) == 0
5276 && TREE_INT_CST_HIGH (arg11) == 0)
5278 HOST_WIDE_INT int01, int11, tmp;
5279 int01 = TREE_INT_CST_LOW (arg01);
5280 int11 = TREE_INT_CST_LOW (arg11);
5282 /* Move min of absolute values to int11. */
5283 if ((int01 >= 0 ? int01 : -int01)
5284 < (int11 >= 0 ? int11 : -int11))
5286 tmp = int01, int01 = int11, int11 = tmp;
5287 alt0 = arg00, arg00 = arg10, arg10 = alt0;
5288 alt0 = arg01, arg01 = arg11, arg11 = alt0;
5291 if (exact_log2 (int11) > 0 && int01 % int11 == 0)
5293 alt0 = fold (build (MULT_EXPR, type, arg00,
5294 build_int_2 (int01 / int11, 0)));
5301 return fold (build (MULT_EXPR, type,
5302 fold (build (PLUS_EXPR, type, alt0, alt1)),
5307 /* See if ARG1 is zero and X + ARG1 reduces to X. */
5308 else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0))
5309 return non_lvalue (convert (type, arg0));
5311 /* Likewise if the operands are reversed. */
5312 else if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
5313 return non_lvalue (convert (type, arg1));
5316 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
5317 is a rotate of A by C1 bits. */
5318 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
5319 is a rotate of A by B bits. */
5321 enum tree_code code0, code1;
5322 code0 = TREE_CODE (arg0);
5323 code1 = TREE_CODE (arg1);
5324 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
5325 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
5326 && operand_equal_p (TREE_OPERAND (arg0, 0),
5327 TREE_OPERAND (arg1, 0), 0)
5328 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5330 tree tree01, tree11;
5331 enum tree_code code01, code11;
5333 tree01 = TREE_OPERAND (arg0, 1);
5334 tree11 = TREE_OPERAND (arg1, 1);
5335 STRIP_NOPS (tree01);
5336 STRIP_NOPS (tree11);
5337 code01 = TREE_CODE (tree01);
5338 code11 = TREE_CODE (tree11);
5339 if (code01 == INTEGER_CST
5340 && code11 == INTEGER_CST
5341 && TREE_INT_CST_HIGH (tree01) == 0
5342 && TREE_INT_CST_HIGH (tree11) == 0
5343 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
5344 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
5345 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
5346 code0 == LSHIFT_EXPR ? tree01 : tree11);
5347 else if (code11 == MINUS_EXPR)
5349 tree tree110, tree111;
5350 tree110 = TREE_OPERAND (tree11, 0);
5351 tree111 = TREE_OPERAND (tree11, 1);
5352 STRIP_NOPS (tree110);
5353 STRIP_NOPS (tree111);
5354 if (TREE_CODE (tree110) == INTEGER_CST
5355 && 0 == compare_tree_int (tree110,
5357 (TREE_TYPE (TREE_OPERAND
5359 && operand_equal_p (tree01, tree111, 0))
5360 return build ((code0 == LSHIFT_EXPR
5363 type, TREE_OPERAND (arg0, 0), tree01);
5365 else if (code01 == MINUS_EXPR)
5367 tree tree010, tree011;
5368 tree010 = TREE_OPERAND (tree01, 0);
5369 tree011 = TREE_OPERAND (tree01, 1);
5370 STRIP_NOPS (tree010);
5371 STRIP_NOPS (tree011);
5372 if (TREE_CODE (tree010) == INTEGER_CST
5373 && 0 == compare_tree_int (tree010,
5375 (TREE_TYPE (TREE_OPERAND
5377 && operand_equal_p (tree11, tree011, 0))
5378 return build ((code0 != LSHIFT_EXPR
5381 type, TREE_OPERAND (arg0, 0), tree11);
5387 /* In most languages, can't associate operations on floats through
5388 parentheses. Rather than remember where the parentheses were, we
5389 don't associate floats at all. It shouldn't matter much. However,
5390 associating multiplications is only very slightly inaccurate, so do
5391 that if -funsafe-math-optimizations is specified. */
5394 && (! FLOAT_TYPE_P (type)
5395 || (flag_unsafe_math_optimizations && code == MULT_EXPR)))
5397 tree var0, con0, lit0, minus_lit0;
5398 tree var1, con1, lit1, minus_lit1;
5400 /* Split both trees into variables, constants, and literals. Then
5401 associate each group together, the constants with literals,
5402 then the result with variables. This increases the chances of
5403 literals being recombined later and of generating relocatable
5404 expressions for the sum of a constant and literal. */
5405 var0 = split_tree (arg0, code, &con0, &lit0, &minus_lit0, 0);
5406 var1 = split_tree (arg1, code, &con1, &lit1, &minus_lit1,
5407 code == MINUS_EXPR);
5409 /* Only do something if we found more than two objects. Otherwise,
5410 nothing has changed and we risk infinite recursion. */
5411 if (2 < ((var0 != 0) + (var1 != 0)
5412 + (con0 != 0) + (con1 != 0)
5413 + (lit0 != 0) + (lit1 != 0)
5414 + (minus_lit0 != 0) + (minus_lit1 != 0)))
5416 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
5417 if (code == MINUS_EXPR)
5420 var0 = associate_trees (var0, var1, code, type);
5421 con0 = associate_trees (con0, con1, code, type);
5422 lit0 = associate_trees (lit0, lit1, code, type);
5423 minus_lit0 = associate_trees (minus_lit0, minus_lit1, code, type);
5425 /* Preserve the MINUS_EXPR if the negative part of the literal is
5426 greater than the positive part. Otherwise, the multiplicative
5427 folding code (i.e extract_muldiv) may be fooled in case
5428 unsigned constants are substracted, like in the following
5429 example: ((X*2 + 4) - 8U)/2. */
5430 if (minus_lit0 && lit0)
5432 if (tree_int_cst_lt (lit0, minus_lit0))
5434 minus_lit0 = associate_trees (minus_lit0, lit0,
5440 lit0 = associate_trees (lit0, minus_lit0,
5448 return convert (type, associate_trees (var0, minus_lit0,
5452 con0 = associate_trees (con0, minus_lit0,
5454 return convert (type, associate_trees (var0, con0,
5459 con0 = associate_trees (con0, lit0, code, type);
5460 return convert (type, associate_trees (var0, con0, code, type));
5466 t1 = const_binop (code, arg0, arg1, 0);
5467 if (t1 != NULL_TREE)
5469 /* The return value should always have
5470 the same type as the original expression. */
5471 if (TREE_TYPE (t1) != TREE_TYPE (t))
5472 t1 = convert (TREE_TYPE (t), t1);
5479 /* A - (-B) -> A + B */
5480 if (TREE_CODE (arg1) == NEGATE_EXPR)
5481 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
5482 /* (-A) - CST -> (-CST) - A for floating point (what about ints ?) */
5483 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
5485 fold (build (MINUS_EXPR, type,
5486 build_real (TREE_TYPE (arg1),
5487 REAL_VALUE_NEGATE (TREE_REAL_CST (arg1))),
5488 TREE_OPERAND (arg0, 0)));
5490 if (! FLOAT_TYPE_P (type))
5492 if (! wins && integer_zerop (arg0))
5493 return negate_expr (convert (type, arg1));
5494 if (integer_zerop (arg1))
5495 return non_lvalue (convert (type, arg0));
5497 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
5498 about the case where C is a constant, just try one of the
5499 four possibilities. */
5501 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
5502 && operand_equal_p (TREE_OPERAND (arg0, 1),
5503 TREE_OPERAND (arg1, 1), 0))
5504 return fold (build (MULT_EXPR, type,
5505 fold (build (MINUS_EXPR, type,
5506 TREE_OPERAND (arg0, 0),
5507 TREE_OPERAND (arg1, 0))),
5508 TREE_OPERAND (arg0, 1)));
5511 /* See if ARG1 is zero and X - ARG1 reduces to X. */
5512 else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 1))
5513 return non_lvalue (convert (type, arg0));
5515 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
5516 ARG0 is zero and X + ARG0 reduces to X, since that would mean
5517 (-ARG1 + ARG0) reduces to -ARG1. */
5518 else if (!wins && fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
5519 return negate_expr (convert (type, arg1));
5521 /* Fold &x - &x. This can happen from &x.foo - &x.
5522 This is unsafe for certain floats even in non-IEEE formats.
5523 In IEEE, it is unsafe because it does wrong for NaNs.
5524 Also note that operand_equal_p is always false if an operand
5527 if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
5528 && operand_equal_p (arg0, arg1, 0))
5529 return convert (type, integer_zero_node);
5534 /* (-A) * (-B) -> A * B */
5535 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
5536 return fold (build (MULT_EXPR, type, TREE_OPERAND (arg0, 0),
5537 TREE_OPERAND (arg1, 0)));
5539 if (! FLOAT_TYPE_P (type))
5541 if (integer_zerop (arg1))
5542 return omit_one_operand (type, arg1, arg0);
5543 if (integer_onep (arg1))
5544 return non_lvalue (convert (type, arg0));
5546 /* (a * (1 << b)) is (a << b) */
5547 if (TREE_CODE (arg1) == LSHIFT_EXPR
5548 && integer_onep (TREE_OPERAND (arg1, 0)))
5549 return fold (build (LSHIFT_EXPR, type, arg0,
5550 TREE_OPERAND (arg1, 1)));
5551 if (TREE_CODE (arg0) == LSHIFT_EXPR
5552 && integer_onep (TREE_OPERAND (arg0, 0)))
5553 return fold (build (LSHIFT_EXPR, type, arg1,
5554 TREE_OPERAND (arg0, 1)));
5556 if (TREE_CODE (arg1) == INTEGER_CST
5557 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5559 return convert (type, tem);
5564 /* Maybe fold x * 0 to 0. The expressions aren't the same
5565 when x is NaN, since x * 0 is also NaN. Nor are they the
5566 same in modes with signed zeros, since multiplying a
5567 negative value by 0 gives -0, not +0. */
5568 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
5569 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0)))
5570 && real_zerop (arg1))
5571 return omit_one_operand (type, arg1, arg0);
5572 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
5573 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5574 && real_onep (arg1))
5575 return non_lvalue (convert (type, arg0));
5577 /* Transform x * -1.0 into -x. */
5578 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5579 && real_minus_onep (arg1))
5580 return fold (build1 (NEGATE_EXPR, type, arg0));
5583 if (! wins && real_twop (arg1)
5584 && (*lang_hooks.decls.global_bindings_p) () == 0
5585 && ! contains_placeholder_p (arg0))
5587 tree arg = save_expr (arg0);
5588 return build (PLUS_EXPR, type, arg, arg);
5591 if (flag_unsafe_math_optimizations)
5593 enum built_in_function fcode0 = builtin_mathfn_code (arg0);
5594 enum built_in_function fcode1 = builtin_mathfn_code (arg1);
5596 /* Optimize sqrt(x)*sqrt(y) as sqrt(x*y). */
5597 if ((fcode0 == BUILT_IN_SQRT && fcode1 == BUILT_IN_SQRT)
5598 || (fcode0 == BUILT_IN_SQRTF && fcode1 == BUILT_IN_SQRTF)
5599 || (fcode0 == BUILT_IN_SQRTL && fcode1 == BUILT_IN_SQRTL))
5601 tree sqrtfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
5602 tree arg = build (MULT_EXPR, type,
5603 TREE_VALUE (TREE_OPERAND (arg0, 1)),
5604 TREE_VALUE (TREE_OPERAND (arg1, 1)));
5605 tree arglist = build_tree_list (NULL_TREE, arg);
5606 return fold (build_function_call_expr (sqrtfn, arglist));
5609 /* Optimize exp(x)*exp(y) as exp(x+y). */
5610 if ((fcode0 == BUILT_IN_EXP && fcode1 == BUILT_IN_EXP)
5611 || (fcode0 == BUILT_IN_EXPF && fcode1 == BUILT_IN_EXPF)
5612 || (fcode0 == BUILT_IN_EXPL && fcode1 == BUILT_IN_EXPL))
5614 tree expfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
5615 tree arg = build (PLUS_EXPR, type,
5616 TREE_VALUE (TREE_OPERAND (arg0, 1)),
5617 TREE_VALUE (TREE_OPERAND (arg1, 1)));
5618 tree arglist = build_tree_list (NULL_TREE, arg);
5619 return fold (build_function_call_expr (expfn, arglist));
5627 if (integer_all_onesp (arg1))
5628 return omit_one_operand (type, arg1, arg0);
5629 if (integer_zerop (arg1))
5630 return non_lvalue (convert (type, arg0));
5631 t1 = distribute_bit_expr (code, type, arg0, arg1);
5632 if (t1 != NULL_TREE)
5635 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
5637 This results in more efficient code for machines without a NAND
5638 instruction. Combine will canonicalize to the first form
5639 which will allow use of NAND instructions provided by the
5640 backend if they exist. */
5641 if (TREE_CODE (arg0) == BIT_NOT_EXPR
5642 && TREE_CODE (arg1) == BIT_NOT_EXPR)
5644 return fold (build1 (BIT_NOT_EXPR, type,
5645 build (BIT_AND_EXPR, type,
5646 TREE_OPERAND (arg0, 0),
5647 TREE_OPERAND (arg1, 0))));
5650 /* See if this can be simplified into a rotate first. If that
5651 is unsuccessful continue in the association code. */
5655 if (integer_zerop (arg1))
5656 return non_lvalue (convert (type, arg0));
5657 if (integer_all_onesp (arg1))
5658 return fold (build1 (BIT_NOT_EXPR, type, arg0));
5660 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
5661 with a constant, and the two constants have no bits in common,
5662 we should treat this as a BIT_IOR_EXPR since this may produce more
5664 if (TREE_CODE (arg0) == BIT_AND_EXPR
5665 && TREE_CODE (arg1) == BIT_AND_EXPR
5666 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5667 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
5668 && integer_zerop (const_binop (BIT_AND_EXPR,
5669 TREE_OPERAND (arg0, 1),
5670 TREE_OPERAND (arg1, 1), 0)))
5672 code = BIT_IOR_EXPR;
5676 /* See if this can be simplified into a rotate first. If that
5677 is unsuccessful continue in the association code. */
5682 if (integer_all_onesp (arg1))
5683 return non_lvalue (convert (type, arg0));
5684 if (integer_zerop (arg1))
5685 return omit_one_operand (type, arg1, arg0);
5686 t1 = distribute_bit_expr (code, type, arg0, arg1);
5687 if (t1 != NULL_TREE)
5689 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
5690 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
5691 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5694 = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
5696 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
5697 && (~TREE_INT_CST_LOW (arg1)
5698 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
5699 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
5702 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
5704 This results in more efficient code for machines without a NOR
5705 instruction. Combine will canonicalize to the first form
5706 which will allow use of NOR instructions provided by the
5707 backend if they exist. */
5708 if (TREE_CODE (arg0) == BIT_NOT_EXPR
5709 && TREE_CODE (arg1) == BIT_NOT_EXPR)
5711 return fold (build1 (BIT_NOT_EXPR, type,
5712 build (BIT_IOR_EXPR, type,
5713 TREE_OPERAND (arg0, 0),
5714 TREE_OPERAND (arg1, 0))));
5719 case BIT_ANDTC_EXPR:
5720 if (integer_all_onesp (arg0))
5721 return non_lvalue (convert (type, arg1));
5722 if (integer_zerop (arg0))
5723 return omit_one_operand (type, arg0, arg1);
5724 if (TREE_CODE (arg1) == INTEGER_CST)
5726 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
5727 code = BIT_AND_EXPR;
5733 /* Don't touch a floating-point divide by zero unless the mode
5734 of the constant can represent infinity. */
5735 if (TREE_CODE (arg1) == REAL_CST
5736 && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg1)))
5737 && real_zerop (arg1))
5740 /* (-A) / (-B) -> A / B */
5741 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
5742 return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
5743 TREE_OPERAND (arg1, 0)));
5745 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
5746 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5747 && real_onep (arg1))
5748 return non_lvalue (convert (type, arg0));
5750 /* If ARG1 is a constant, we can convert this to a multiply by the
5751 reciprocal. This does not have the same rounding properties,
5752 so only do this if -funsafe-math-optimizations. We can actually
5753 always safely do it if ARG1 is a power of two, but it's hard to
5754 tell if it is or not in a portable manner. */
5755 if (TREE_CODE (arg1) == REAL_CST)
5757 if (flag_unsafe_math_optimizations
5758 && 0 != (tem = const_binop (code, build_real (type, dconst1),
5760 return fold (build (MULT_EXPR, type, arg0, tem));
5761 /* Find the reciprocal if optimizing and the result is exact. */
5765 r = TREE_REAL_CST (arg1);
5766 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
5768 tem = build_real (type, r);
5769 return fold (build (MULT_EXPR, type, arg0, tem));
5773 /* Convert A/B/C to A/(B*C). */
5774 if (flag_unsafe_math_optimizations
5775 && TREE_CODE (arg0) == RDIV_EXPR)
5777 return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
5778 build (MULT_EXPR, type, TREE_OPERAND (arg0, 1),
5781 /* Convert A/(B/C) to (A/B)*C. */
5782 if (flag_unsafe_math_optimizations
5783 && TREE_CODE (arg1) == RDIV_EXPR)
5785 return fold (build (MULT_EXPR, type,
5786 build (RDIV_EXPR, type, arg0,
5787 TREE_OPERAND (arg1, 0)),
5788 TREE_OPERAND (arg1, 1)));
5791 /* Optimize x/exp(y) into x*exp(-y). */
5792 if (flag_unsafe_math_optimizations)
5794 enum built_in_function fcode = builtin_mathfn_code (arg1);
5795 if (fcode == BUILT_IN_EXP
5796 || fcode == BUILT_IN_EXPF
5797 || fcode == BUILT_IN_EXPL)
5799 tree expfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
5800 tree arg = build1 (NEGATE_EXPR, type,
5801 TREE_VALUE (TREE_OPERAND (arg1, 1)));
5802 tree arglist = build_tree_list (NULL_TREE, arg);
5803 arg1 = build_function_call_expr (expfn, arglist);
5804 return fold (build (MULT_EXPR, type, arg0, arg1));
5809 case TRUNC_DIV_EXPR:
5810 case ROUND_DIV_EXPR:
5811 case FLOOR_DIV_EXPR:
5813 case EXACT_DIV_EXPR:
5814 if (integer_onep (arg1))
5815 return non_lvalue (convert (type, arg0));
5816 if (integer_zerop (arg1))
5819 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
5820 operation, EXACT_DIV_EXPR.
5822 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
5823 At one time others generated faster code, it's not clear if they do
5824 after the last round to changes to the DIV code in expmed.c. */
5825 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
5826 && multiple_of_p (type, arg0, arg1))
5827 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
5829 if (TREE_CODE (arg1) == INTEGER_CST
5830 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5832 return convert (type, tem);
5837 case FLOOR_MOD_EXPR:
5838 case ROUND_MOD_EXPR:
5839 case TRUNC_MOD_EXPR:
5840 if (integer_onep (arg1))
5841 return omit_one_operand (type, integer_zero_node, arg0);
5842 if (integer_zerop (arg1))
5845 if (TREE_CODE (arg1) == INTEGER_CST
5846 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5848 return convert (type, tem);
5854 if (integer_all_onesp (arg0))
5855 return omit_one_operand (type, arg0, arg1);
5859 /* Optimize -1 >> x for arithmetic right shifts. */
5860 if (integer_all_onesp (arg0) && ! TREE_UNSIGNED (type))
5861 return omit_one_operand (type, arg0, arg1);
5862 /* ... fall through ... */
5866 if (integer_zerop (arg1))
5867 return non_lvalue (convert (type, arg0));
5868 if (integer_zerop (arg0))
5869 return omit_one_operand (type, arg0, arg1);
5871 /* Since negative shift count is not well-defined,
5872 don't try to compute it in the compiler. */
5873 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
5875 /* Rewrite an LROTATE_EXPR by a constant into an
5876 RROTATE_EXPR by a new constant. */
5877 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
5879 TREE_SET_CODE (t, RROTATE_EXPR);
5880 code = RROTATE_EXPR;
5881 TREE_OPERAND (t, 1) = arg1
5884 convert (TREE_TYPE (arg1),
5885 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
5887 if (tree_int_cst_sgn (arg1) < 0)
5891 /* If we have a rotate of a bit operation with the rotate count and
5892 the second operand of the bit operation both constant,
5893 permute the two operations. */
5894 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5895 && (TREE_CODE (arg0) == BIT_AND_EXPR
5896 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
5897 || TREE_CODE (arg0) == BIT_IOR_EXPR
5898 || TREE_CODE (arg0) == BIT_XOR_EXPR)
5899 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
5900 return fold (build (TREE_CODE (arg0), type,
5901 fold (build (code, type,
5902 TREE_OPERAND (arg0, 0), arg1)),
5903 fold (build (code, type,
5904 TREE_OPERAND (arg0, 1), arg1))));
5906 /* Two consecutive rotates adding up to the width of the mode can
5908 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5909 && TREE_CODE (arg0) == RROTATE_EXPR
5910 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5911 && TREE_INT_CST_HIGH (arg1) == 0
5912 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
5913 && ((TREE_INT_CST_LOW (arg1)
5914 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
5915 == (unsigned int) GET_MODE_BITSIZE (TYPE_MODE (type))))
5916 return TREE_OPERAND (arg0, 0);
5921 if (operand_equal_p (arg0, arg1, 0))
5922 return omit_one_operand (type, arg0, arg1);
5923 if (INTEGRAL_TYPE_P (type)
5924 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
5925 return omit_one_operand (type, arg1, arg0);
5929 if (operand_equal_p (arg0, arg1, 0))
5930 return omit_one_operand (type, arg0, arg1);
5931 if (INTEGRAL_TYPE_P (type)
5932 && TYPE_MAX_VALUE (type)
5933 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
5934 return omit_one_operand (type, arg1, arg0);
5937 case TRUTH_NOT_EXPR:
5938 /* Note that the operand of this must be an int
5939 and its values must be 0 or 1.
5940 ("true" is a fixed value perhaps depending on the language,
5941 but we don't handle values other than 1 correctly yet.) */
5942 tem = invert_truthvalue (arg0);
5943 /* Avoid infinite recursion. */
5944 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
5946 return convert (type, tem);
5948 case TRUTH_ANDIF_EXPR:
5949 /* Note that the operands of this must be ints
5950 and their values must be 0 or 1.
5951 ("true" is a fixed value perhaps depending on the language.) */
5952 /* If first arg is constant zero, return it. */
5953 if (integer_zerop (arg0))
5954 return convert (type, arg0);
5955 case TRUTH_AND_EXPR:
5956 /* If either arg is constant true, drop it. */
5957 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5958 return non_lvalue (convert (type, arg1));
5959 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)
5960 /* Preserve sequence points. */
5961 && (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
5962 return non_lvalue (convert (type, arg0));
5963 /* If second arg is constant zero, result is zero, but first arg
5964 must be evaluated. */
5965 if (integer_zerop (arg1))
5966 return omit_one_operand (type, arg1, arg0);
5967 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
5968 case will be handled here. */
5969 if (integer_zerop (arg0))
5970 return omit_one_operand (type, arg0, arg1);
5973 /* We only do these simplifications if we are optimizing. */
5977 /* Check for things like (A || B) && (A || C). We can convert this
5978 to A || (B && C). Note that either operator can be any of the four
5979 truth and/or operations and the transformation will still be
5980 valid. Also note that we only care about order for the
5981 ANDIF and ORIF operators. If B contains side effects, this
5982 might change the truth-value of A. */
5983 if (TREE_CODE (arg0) == TREE_CODE (arg1)
5984 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
5985 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
5986 || TREE_CODE (arg0) == TRUTH_AND_EXPR
5987 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
5988 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
5990 tree a00 = TREE_OPERAND (arg0, 0);
5991 tree a01 = TREE_OPERAND (arg0, 1);
5992 tree a10 = TREE_OPERAND (arg1, 0);
5993 tree a11 = TREE_OPERAND (arg1, 1);
5994 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5995 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5996 && (code == TRUTH_AND_EXPR
5997 || code == TRUTH_OR_EXPR));
5999 if (operand_equal_p (a00, a10, 0))
6000 return fold (build (TREE_CODE (arg0), type, a00,
6001 fold (build (code, type, a01, a11))));
6002 else if (commutative && operand_equal_p (a00, a11, 0))
6003 return fold (build (TREE_CODE (arg0), type, a00,
6004 fold (build (code, type, a01, a10))));
6005 else if (commutative && operand_equal_p (a01, a10, 0))
6006 return fold (build (TREE_CODE (arg0), type, a01,
6007 fold (build (code, type, a00, a11))));
6009 /* This case if tricky because we must either have commutative
6010 operators or else A10 must not have side-effects. */
6012 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
6013 && operand_equal_p (a01, a11, 0))
6014 return fold (build (TREE_CODE (arg0), type,
6015 fold (build (code, type, a00, a10)),
6019 /* See if we can build a range comparison. */
6020 if (0 != (tem = fold_range_test (t)))
6023 /* Check for the possibility of merging component references. If our
6024 lhs is another similar operation, try to merge its rhs with our
6025 rhs. Then try to merge our lhs and rhs. */
6026 if (TREE_CODE (arg0) == code
6027 && 0 != (tem = fold_truthop (code, type,
6028 TREE_OPERAND (arg0, 1), arg1)))
6029 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6031 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
6036 case TRUTH_ORIF_EXPR:
6037 /* Note that the operands of this must be ints
6038 and their values must be 0 or true.
6039 ("true" is a fixed value perhaps depending on the language.) */
6040 /* If first arg is constant true, return it. */
6041 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
6042 return convert (type, arg0);
6044 /* If either arg is constant zero, drop it. */
6045 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
6046 return non_lvalue (convert (type, arg1));
6047 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)
6048 /* Preserve sequence points. */
6049 && (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
6050 return non_lvalue (convert (type, arg0));
6051 /* If second arg is constant true, result is true, but we must
6052 evaluate first arg. */
6053 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
6054 return omit_one_operand (type, arg1, arg0);
6055 /* Likewise for first arg, but note this only occurs here for
6057 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
6058 return omit_one_operand (type, arg0, arg1);
6061 case TRUTH_XOR_EXPR:
6062 /* If either arg is constant zero, drop it. */
6063 if (integer_zerop (arg0))
6064 return non_lvalue (convert (type, arg1));
6065 if (integer_zerop (arg1))
6066 return non_lvalue (convert (type, arg0));
6067 /* If either arg is constant true, this is a logical inversion. */
6068 if (integer_onep (arg0))
6069 return non_lvalue (convert (type, invert_truthvalue (arg1)));
6070 if (integer_onep (arg1))
6071 return non_lvalue (convert (type, invert_truthvalue (arg0)));
6080 /* If one arg is a real or integer constant, put it last. */
6081 if ((TREE_CODE (arg0) == INTEGER_CST
6082 && TREE_CODE (arg1) != INTEGER_CST)
6083 || (TREE_CODE (arg0) == REAL_CST
6084 && TREE_CODE (arg0) != REAL_CST))
6086 TREE_OPERAND (t, 0) = arg1;
6087 TREE_OPERAND (t, 1) = arg0;
6088 arg0 = TREE_OPERAND (t, 0);
6089 arg1 = TREE_OPERAND (t, 1);
6090 code = swap_tree_comparison (code);
6091 TREE_SET_CODE (t, code);
6094 if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
6096 tree targ0 = strip_float_extensions (arg0);
6097 tree targ1 = strip_float_extensions (arg1);
6098 tree newtype = TREE_TYPE (targ0);
6100 if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype))
6101 newtype = TREE_TYPE (targ1);
6103 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
6104 if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0)))
6105 return fold (build (code, type, convert (newtype, targ0),
6106 convert (newtype, targ1)));
6108 /* (-a) CMP (-b) -> b CMP a */
6109 if (TREE_CODE (arg0) == NEGATE_EXPR
6110 && TREE_CODE (arg1) == NEGATE_EXPR)
6111 return fold (build (code, type, TREE_OPERAND (arg1, 0),
6112 TREE_OPERAND (arg0, 0)));
6113 /* (-a) CMP CST -> a swap(CMP) (-CST) */
6114 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
6117 (swap_tree_comparison (code), type,
6118 TREE_OPERAND (arg0, 0),
6119 build_real (TREE_TYPE (arg1),
6120 REAL_VALUE_NEGATE (TREE_REAL_CST (arg1)))));
6121 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
6122 /* a CMP (-0) -> a CMP 0 */
6123 if (TREE_CODE (arg1) == REAL_CST
6124 && REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
6125 return fold (build (code, type, arg0,
6126 build_real (TREE_TYPE (arg1), dconst0)));
6128 /* If this is a comparison of a real constant with a PLUS_EXPR
6129 or a MINUS_EXPR of a real constant, we can convert it into a
6130 comparison with a revised real constant as long as no overflow
6131 occurs when unsafe_math_optimizations are enabled. */
6132 if (flag_unsafe_math_optimizations
6133 && TREE_CODE (arg1) == REAL_CST
6134 && (TREE_CODE (arg0) == PLUS_EXPR
6135 || TREE_CODE (arg0) == MINUS_EXPR)
6136 && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
6137 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
6138 ? MINUS_EXPR : PLUS_EXPR,
6139 arg1, TREE_OPERAND (arg0, 1), 0))
6140 && ! TREE_CONSTANT_OVERFLOW (tem))
6141 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6144 /* Convert foo++ == CONST into ++foo == CONST + INCR.
6145 First, see if one arg is constant; find the constant arg
6146 and the other one. */
6148 tree constop = 0, varop = NULL_TREE;
6149 int constopnum = -1;
6151 if (TREE_CONSTANT (arg1))
6152 constopnum = 1, constop = arg1, varop = arg0;
6153 if (TREE_CONSTANT (arg0))
6154 constopnum = 0, constop = arg0, varop = arg1;
6156 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
6158 /* This optimization is invalid for ordered comparisons
6159 if CONST+INCR overflows or if foo+incr might overflow.
6160 This optimization is invalid for floating point due to rounding.
6161 For pointer types we assume overflow doesn't happen. */
6162 if (POINTER_TYPE_P (TREE_TYPE (varop))
6163 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
6164 && (code == EQ_EXPR || code == NE_EXPR)))
6167 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
6168 constop, TREE_OPERAND (varop, 1)));
6170 /* Do not overwrite the current varop to be a preincrement,
6171 create a new node so that we won't confuse our caller who
6172 might create trees and throw them away, reusing the
6173 arguments that they passed to build. This shows up in
6174 the THEN or ELSE parts of ?: being postincrements. */
6175 varop = build (PREINCREMENT_EXPR, TREE_TYPE (varop),
6176 TREE_OPERAND (varop, 0),
6177 TREE_OPERAND (varop, 1));
6179 /* If VAROP is a reference to a bitfield, we must mask
6180 the constant by the width of the field. */
6181 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
6182 && DECL_BIT_FIELD(TREE_OPERAND
6183 (TREE_OPERAND (varop, 0), 1)))
6186 = TREE_INT_CST_LOW (DECL_SIZE
6188 (TREE_OPERAND (varop, 0), 1)));
6189 tree mask, unsigned_type;
6190 unsigned int precision;
6191 tree folded_compare;
6193 /* First check whether the comparison would come out
6194 always the same. If we don't do that we would
6195 change the meaning with the masking. */
6196 if (constopnum == 0)
6197 folded_compare = fold (build (code, type, constop,
6198 TREE_OPERAND (varop, 0)));
6200 folded_compare = fold (build (code, type,
6201 TREE_OPERAND (varop, 0),
6203 if (integer_zerop (folded_compare)
6204 || integer_onep (folded_compare))
6205 return omit_one_operand (type, folded_compare, varop);
6207 unsigned_type = (*lang_hooks.types.type_for_size)(size, 1);
6208 precision = TYPE_PRECISION (unsigned_type);
6209 mask = build_int_2 (~0, ~0);
6210 TREE_TYPE (mask) = unsigned_type;
6211 force_fit_type (mask, 0);
6212 mask = const_binop (RSHIFT_EXPR, mask,
6213 size_int (precision - size), 0);
6214 newconst = fold (build (BIT_AND_EXPR,
6215 TREE_TYPE (varop), newconst,
6216 convert (TREE_TYPE (varop),
6220 t = build (code, type,
6221 (constopnum == 0) ? newconst : varop,
6222 (constopnum == 1) ? newconst : varop);
6226 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
6228 if (POINTER_TYPE_P (TREE_TYPE (varop))
6229 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
6230 && (code == EQ_EXPR || code == NE_EXPR)))
6233 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
6234 constop, TREE_OPERAND (varop, 1)));
6236 /* Do not overwrite the current varop to be a predecrement,
6237 create a new node so that we won't confuse our caller who
6238 might create trees and throw them away, reusing the
6239 arguments that they passed to build. This shows up in
6240 the THEN or ELSE parts of ?: being postdecrements. */
6241 varop = build (PREDECREMENT_EXPR, TREE_TYPE (varop),
6242 TREE_OPERAND (varop, 0),
6243 TREE_OPERAND (varop, 1));
6245 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
6246 && DECL_BIT_FIELD(TREE_OPERAND
6247 (TREE_OPERAND (varop, 0), 1)))
6250 = TREE_INT_CST_LOW (DECL_SIZE
6252 (TREE_OPERAND (varop, 0), 1)));
6253 tree mask, unsigned_type;
6254 unsigned int precision;
6255 tree folded_compare;
6257 if (constopnum == 0)
6258 folded_compare = fold (build (code, type, constop,
6259 TREE_OPERAND (varop, 0)));
6261 folded_compare = fold (build (code, type,
6262 TREE_OPERAND (varop, 0),
6264 if (integer_zerop (folded_compare)
6265 || integer_onep (folded_compare))
6266 return omit_one_operand (type, folded_compare, varop);
6268 unsigned_type = (*lang_hooks.types.type_for_size)(size, 1);
6269 precision = TYPE_PRECISION (unsigned_type);
6270 mask = build_int_2 (~0, ~0);
6271 TREE_TYPE (mask) = TREE_TYPE (varop);
6272 force_fit_type (mask, 0);
6273 mask = const_binop (RSHIFT_EXPR, mask,
6274 size_int (precision - size), 0);
6275 newconst = fold (build (BIT_AND_EXPR,
6276 TREE_TYPE (varop), newconst,
6277 convert (TREE_TYPE (varop),
6281 t = build (code, type,
6282 (constopnum == 0) ? newconst : varop,
6283 (constopnum == 1) ? newconst : varop);
6289 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
6290 This transformation affects the cases which are handled in later
6291 optimizations involving comparisons with non-negative constants. */
6292 if (TREE_CODE (arg1) == INTEGER_CST
6293 && TREE_CODE (arg0) != INTEGER_CST
6294 && tree_int_cst_sgn (arg1) > 0)
6300 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6301 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6306 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6307 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6315 /* Comparisons with the highest or lowest possible integer of
6316 the specified size will have known values. */
6318 int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1)));
6320 if (TREE_CODE (arg1) == INTEGER_CST
6321 && ! TREE_CONSTANT_OVERFLOW (arg1)
6322 && width <= HOST_BITS_PER_WIDE_INT
6323 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
6324 || POINTER_TYPE_P (TREE_TYPE (arg1))))
6326 unsigned HOST_WIDE_INT signed_max;
6327 unsigned HOST_WIDE_INT max, min;
6329 signed_max = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1;
6331 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6333 max = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
6339 min = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
6342 if (TREE_INT_CST_HIGH (arg1) == 0
6343 && TREE_INT_CST_LOW (arg1) == max)
6347 return omit_one_operand (type,
6348 convert (type, integer_zero_node),
6352 TREE_SET_CODE (t, EQ_EXPR);
6355 return omit_one_operand (type,
6356 convert (type, integer_one_node),
6360 TREE_SET_CODE (t, NE_EXPR);
6363 /* The GE_EXPR and LT_EXPR cases above are not normally
6364 reached because of previous transformations. */
6369 else if (TREE_INT_CST_HIGH (arg1) == 0
6370 && TREE_INT_CST_LOW (arg1) == max - 1)
6375 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
6376 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6380 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
6381 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6386 else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
6387 && TREE_INT_CST_LOW (arg1) == min)
6391 return omit_one_operand (type,
6392 convert (type, integer_zero_node),
6396 TREE_SET_CODE (t, EQ_EXPR);
6400 return omit_one_operand (type,
6401 convert (type, integer_one_node),
6405 TREE_SET_CODE (t, NE_EXPR);
6411 else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
6412 && TREE_INT_CST_LOW (arg1) == min + 1)
6417 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6418 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6422 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6423 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6429 else if (TREE_INT_CST_HIGH (arg1) == 0
6430 && TREE_INT_CST_LOW (arg1) == signed_max
6431 && TREE_UNSIGNED (TREE_TYPE (arg1))
6432 /* signed_type does not work on pointer types. */
6433 && INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
6435 /* The following case also applies to X < signed_max+1
6436 and X >= signed_max+1 because previous transformations. */
6437 if (code == LE_EXPR || code == GT_EXPR)
6440 st0 = (*lang_hooks.types.signed_type) (TREE_TYPE (arg0));
6441 st1 = (*lang_hooks.types.signed_type) (TREE_TYPE (arg1));
6443 (build (code == LE_EXPR ? GE_EXPR: LT_EXPR,
6444 type, convert (st0, arg0),
6445 convert (st1, integer_zero_node)));
6451 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
6452 a MINUS_EXPR of a constant, we can convert it into a comparison with
6453 a revised constant as long as no overflow occurs. */
6454 if ((code == EQ_EXPR || code == NE_EXPR)
6455 && TREE_CODE (arg1) == INTEGER_CST
6456 && (TREE_CODE (arg0) == PLUS_EXPR
6457 || TREE_CODE (arg0) == MINUS_EXPR)
6458 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
6459 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
6460 ? MINUS_EXPR : PLUS_EXPR,
6461 arg1, TREE_OPERAND (arg0, 1), 0))
6462 && ! TREE_CONSTANT_OVERFLOW (tem))
6463 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6465 /* Similarly for a NEGATE_EXPR. */
6466 else if ((code == EQ_EXPR || code == NE_EXPR)
6467 && TREE_CODE (arg0) == NEGATE_EXPR
6468 && TREE_CODE (arg1) == INTEGER_CST
6469 && 0 != (tem = negate_expr (arg1))
6470 && TREE_CODE (tem) == INTEGER_CST
6471 && ! TREE_CONSTANT_OVERFLOW (tem))
6472 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6474 /* If we have X - Y == 0, we can convert that to X == Y and similarly
6475 for !=. Don't do this for ordered comparisons due to overflow. */
6476 else if ((code == NE_EXPR || code == EQ_EXPR)
6477 && integer_zerop (arg1) && TREE_CODE (arg0) == MINUS_EXPR)
6478 return fold (build (code, type,
6479 TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)));
6481 /* If we are widening one operand of an integer comparison,
6482 see if the other operand is similarly being widened. Perhaps we
6483 can do the comparison in the narrower type. */
6484 else if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE
6485 && TREE_CODE (arg0) == NOP_EXPR
6486 && (tem = get_unwidened (arg0, NULL_TREE)) != arg0
6487 && (t1 = get_unwidened (arg1, TREE_TYPE (tem))) != 0
6488 && (TREE_TYPE (t1) == TREE_TYPE (tem)
6489 || (TREE_CODE (t1) == INTEGER_CST
6490 && int_fits_type_p (t1, TREE_TYPE (tem)))))
6491 return fold (build (code, type, tem, convert (TREE_TYPE (tem), t1)));
6493 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
6494 constant, we can simplify it. */
6495 else if (TREE_CODE (arg1) == INTEGER_CST
6496 && (TREE_CODE (arg0) == MIN_EXPR
6497 || TREE_CODE (arg0) == MAX_EXPR)
6498 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
6499 return optimize_minmax_comparison (t);
6501 /* If we are comparing an ABS_EXPR with a constant, we can
6502 convert all the cases into explicit comparisons, but they may
6503 well not be faster than doing the ABS and one comparison.
6504 But ABS (X) <= C is a range comparison, which becomes a subtraction
6505 and a comparison, and is probably faster. */
6506 else if (code == LE_EXPR && TREE_CODE (arg1) == INTEGER_CST
6507 && TREE_CODE (arg0) == ABS_EXPR
6508 && ! TREE_SIDE_EFFECTS (arg0)
6509 && (0 != (tem = negate_expr (arg1)))
6510 && TREE_CODE (tem) == INTEGER_CST
6511 && ! TREE_CONSTANT_OVERFLOW (tem))
6512 return fold (build (TRUTH_ANDIF_EXPR, type,
6513 build (GE_EXPR, type, TREE_OPERAND (arg0, 0), tem),
6514 build (LE_EXPR, type,
6515 TREE_OPERAND (arg0, 0), arg1)));
6517 /* If this is an EQ or NE comparison with zero and ARG0 is
6518 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
6519 two operations, but the latter can be done in one less insn
6520 on machines that have only two-operand insns or on which a
6521 constant cannot be the first operand. */
6522 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
6523 && TREE_CODE (arg0) == BIT_AND_EXPR)
6525 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
6526 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
6528 fold (build (code, type,
6529 build (BIT_AND_EXPR, TREE_TYPE (arg0),
6531 TREE_TYPE (TREE_OPERAND (arg0, 0)),
6532 TREE_OPERAND (arg0, 1),
6533 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
6534 convert (TREE_TYPE (arg0),
6537 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
6538 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
6540 fold (build (code, type,
6541 build (BIT_AND_EXPR, TREE_TYPE (arg0),
6543 TREE_TYPE (TREE_OPERAND (arg0, 1)),
6544 TREE_OPERAND (arg0, 0),
6545 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
6546 convert (TREE_TYPE (arg0),
6551 /* If this is an NE or EQ comparison of zero against the result of a
6552 signed MOD operation whose second operand is a power of 2, make
6553 the MOD operation unsigned since it is simpler and equivalent. */
6554 if ((code == NE_EXPR || code == EQ_EXPR)
6555 && integer_zerop (arg1)
6556 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
6557 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
6558 || TREE_CODE (arg0) == CEIL_MOD_EXPR
6559 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
6560 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
6561 && integer_pow2p (TREE_OPERAND (arg0, 1)))
6563 tree newtype = (*lang_hooks.types.unsigned_type) (TREE_TYPE (arg0));
6564 tree newmod = build (TREE_CODE (arg0), newtype,
6565 convert (newtype, TREE_OPERAND (arg0, 0)),
6566 convert (newtype, TREE_OPERAND (arg0, 1)));
6568 return build (code, type, newmod, convert (newtype, arg1));
6571 /* If this is an NE comparison of zero with an AND of one, remove the
6572 comparison since the AND will give the correct value. */
6573 if (code == NE_EXPR && integer_zerop (arg1)
6574 && TREE_CODE (arg0) == BIT_AND_EXPR
6575 && integer_onep (TREE_OPERAND (arg0, 1)))
6576 return convert (type, arg0);
6578 /* If we have (A & C) == C where C is a power of 2, convert this into
6579 (A & C) != 0. Similarly for NE_EXPR. */
6580 if ((code == EQ_EXPR || code == NE_EXPR)
6581 && TREE_CODE (arg0) == BIT_AND_EXPR
6582 && integer_pow2p (TREE_OPERAND (arg0, 1))
6583 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
6584 return fold (build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
6585 arg0, integer_zero_node));
6587 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6588 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6589 if ((code == EQ_EXPR || code == NE_EXPR)
6590 && TREE_CODE (arg0) == BIT_AND_EXPR
6591 && integer_zerop (arg1))
6593 tree arg00 = sign_bit_p (TREE_OPERAND (arg0, 0),
6594 TREE_OPERAND (arg0, 1));
6595 if (arg00 != NULL_TREE)
6597 tree stype = (*lang_hooks.types.signed_type) (TREE_TYPE (arg00));
6598 return fold (build (code == EQ_EXPR ? GE_EXPR : LT_EXPR, type,
6599 convert (stype, arg00),
6600 convert (stype, integer_zero_node)));
6604 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
6605 and similarly for >= into !=. */
6606 if ((code == LT_EXPR || code == GE_EXPR)
6607 && TREE_UNSIGNED (TREE_TYPE (arg0))
6608 && TREE_CODE (arg1) == LSHIFT_EXPR
6609 && integer_onep (TREE_OPERAND (arg1, 0)))
6610 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
6611 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
6612 TREE_OPERAND (arg1, 1)),
6613 convert (TREE_TYPE (arg0), integer_zero_node));
6615 else if ((code == LT_EXPR || code == GE_EXPR)
6616 && TREE_UNSIGNED (TREE_TYPE (arg0))
6617 && (TREE_CODE (arg1) == NOP_EXPR
6618 || TREE_CODE (arg1) == CONVERT_EXPR)
6619 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
6620 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
6622 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
6623 convert (TREE_TYPE (arg0),
6624 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
6625 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
6626 convert (TREE_TYPE (arg0), integer_zero_node));
6628 /* Simplify comparison of something with itself. (For IEEE
6629 floating-point, we can only do some of these simplifications.) */
6630 if (operand_equal_p (arg0, arg1, 0))
6637 if (! FLOAT_TYPE_P (TREE_TYPE (arg0)))
6638 return constant_boolean_node (1, type);
6640 TREE_SET_CODE (t, code);
6644 /* For NE, we can only do this simplification if integer. */
6645 if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
6647 /* ... fall through ... */
6650 return constant_boolean_node (0, type);
6656 /* If we are comparing an expression that just has comparisons
6657 of two integer values, arithmetic expressions of those comparisons,
6658 and constants, we can simplify it. There are only three cases
6659 to check: the two values can either be equal, the first can be
6660 greater, or the second can be greater. Fold the expression for
6661 those three values. Since each value must be 0 or 1, we have
6662 eight possibilities, each of which corresponds to the constant 0
6663 or 1 or one of the six possible comparisons.
6665 This handles common cases like (a > b) == 0 but also handles
6666 expressions like ((x > y) - (y > x)) > 0, which supposedly
6667 occur in macroized code. */
6669 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
6671 tree cval1 = 0, cval2 = 0;
6674 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
6675 /* Don't handle degenerate cases here; they should already
6676 have been handled anyway. */
6677 && cval1 != 0 && cval2 != 0
6678 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
6679 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
6680 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
6681 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
6682 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
6683 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
6684 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
6686 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
6687 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
6689 /* We can't just pass T to eval_subst in case cval1 or cval2
6690 was the same as ARG1. */
6693 = fold (build (code, type,
6694 eval_subst (arg0, cval1, maxval, cval2, minval),
6697 = fold (build (code, type,
6698 eval_subst (arg0, cval1, maxval, cval2, maxval),
6701 = fold (build (code, type,
6702 eval_subst (arg0, cval1, minval, cval2, maxval),
6705 /* All three of these results should be 0 or 1. Confirm they
6706 are. Then use those values to select the proper code
6709 if ((integer_zerop (high_result)
6710 || integer_onep (high_result))
6711 && (integer_zerop (equal_result)
6712 || integer_onep (equal_result))
6713 && (integer_zerop (low_result)
6714 || integer_onep (low_result)))
6716 /* Make a 3-bit mask with the high-order bit being the
6717 value for `>', the next for '=', and the low for '<'. */
6718 switch ((integer_onep (high_result) * 4)
6719 + (integer_onep (equal_result) * 2)
6720 + integer_onep (low_result))
6724 return omit_one_operand (type, integer_zero_node, arg0);
6745 return omit_one_operand (type, integer_one_node, arg0);
6748 t = build (code, type, cval1, cval2);
6750 return save_expr (t);
6757 /* If this is a comparison of a field, we may be able to simplify it. */
6758 if (((TREE_CODE (arg0) == COMPONENT_REF
6759 && (*lang_hooks.can_use_bit_fields_p) ())
6760 || TREE_CODE (arg0) == BIT_FIELD_REF)
6761 && (code == EQ_EXPR || code == NE_EXPR)
6762 /* Handle the constant case even without -O
6763 to make sure the warnings are given. */
6764 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
6766 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
6770 /* If this is a comparison of complex values and either or both sides
6771 are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
6772 comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
6773 This may prevent needless evaluations. */
6774 if ((code == EQ_EXPR || code == NE_EXPR)
6775 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
6776 && (TREE_CODE (arg0) == COMPLEX_EXPR
6777 || TREE_CODE (arg1) == COMPLEX_EXPR
6778 || TREE_CODE (arg0) == COMPLEX_CST
6779 || TREE_CODE (arg1) == COMPLEX_CST))
6781 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
6782 tree real0, imag0, real1, imag1;
6784 arg0 = save_expr (arg0);
6785 arg1 = save_expr (arg1);
6786 real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
6787 imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
6788 real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
6789 imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
6791 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
6794 fold (build (code, type, real0, real1)),
6795 fold (build (code, type, imag0, imag1))));
6798 /* Optimize comparisons of strlen vs zero to a compare of the
6799 first character of the string vs zero. To wit,
6800 strlen(ptr) == 0 => *ptr == 0
6801 strlen(ptr) != 0 => *ptr != 0
6802 Other cases should reduce to one of these two (or a constant)
6803 due to the return value of strlen being unsigned. */
6804 if ((code == EQ_EXPR || code == NE_EXPR)
6805 && integer_zerop (arg1)
6806 && TREE_CODE (arg0) == CALL_EXPR
6807 && TREE_CODE (TREE_OPERAND (arg0, 0)) == ADDR_EXPR)
6809 tree fndecl = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
6812 if (TREE_CODE (fndecl) == FUNCTION_DECL
6813 && DECL_BUILT_IN (fndecl)
6814 && DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_MD
6815 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STRLEN
6816 && (arglist = TREE_OPERAND (arg0, 1))
6817 && TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) == POINTER_TYPE
6818 && ! TREE_CHAIN (arglist))
6819 return fold (build (code, type,
6820 build1 (INDIRECT_REF, char_type_node,
6821 TREE_VALUE(arglist)),
6822 integer_zero_node));
6825 /* From here on, the only cases we handle are when the result is
6826 known to be a constant.
6828 To compute GT, swap the arguments and do LT.
6829 To compute GE, do LT and invert the result.
6830 To compute LE, swap the arguments, do LT and invert the result.
6831 To compute NE, do EQ and invert the result.
6833 Therefore, the code below must handle only EQ and LT. */
6835 if (code == LE_EXPR || code == GT_EXPR)
6837 tem = arg0, arg0 = arg1, arg1 = tem;
6838 code = swap_tree_comparison (code);
6841 /* Note that it is safe to invert for real values here because we
6842 will check below in the one case that it matters. */
6846 if (code == NE_EXPR || code == GE_EXPR)
6849 code = invert_tree_comparison (code);
6852 /* Compute a result for LT or EQ if args permit;
6853 otherwise return T. */
6854 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
6856 if (code == EQ_EXPR)
6857 t1 = build_int_2 (tree_int_cst_equal (arg0, arg1), 0);
6859 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
6860 ? INT_CST_LT_UNSIGNED (arg0, arg1)
6861 : INT_CST_LT (arg0, arg1)),
6865 #if 0 /* This is no longer useful, but breaks some real code. */
6866 /* Assume a nonexplicit constant cannot equal an explicit one,
6867 since such code would be undefined anyway.
6868 Exception: on sysvr4, using #pragma weak,
6869 a label can come out as 0. */
6870 else if (TREE_CODE (arg1) == INTEGER_CST
6871 && !integer_zerop (arg1)
6872 && TREE_CONSTANT (arg0)
6873 && TREE_CODE (arg0) == ADDR_EXPR
6875 t1 = build_int_2 (0, 0);
6877 /* Two real constants can be compared explicitly. */
6878 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
6880 /* If either operand is a NaN, the result is false with two
6881 exceptions: First, an NE_EXPR is true on NaNs, but that case
6882 is already handled correctly since we will be inverting the
6883 result for NE_EXPR. Second, if we had inverted a LE_EXPR
6884 or a GE_EXPR into a LT_EXPR, we must return true so that it
6885 will be inverted into false. */
6887 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
6888 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
6889 t1 = build_int_2 (invert && code == LT_EXPR, 0);
6891 else if (code == EQ_EXPR)
6892 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
6893 TREE_REAL_CST (arg1)),
6896 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
6897 TREE_REAL_CST (arg1)),
6901 if (t1 == NULL_TREE)
6905 TREE_INT_CST_LOW (t1) ^= 1;
6907 TREE_TYPE (t1) = type;
6908 if (TREE_CODE (type) == BOOLEAN_TYPE)
6909 return (*lang_hooks.truthvalue_conversion) (t1);
6913 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
6914 so all simple results must be passed through pedantic_non_lvalue. */
6915 if (TREE_CODE (arg0) == INTEGER_CST)
6916 return pedantic_non_lvalue
6917 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
6918 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
6919 return pedantic_omit_one_operand (type, arg1, arg0);
6921 /* If the second operand is zero, invert the comparison and swap
6922 the second and third operands. Likewise if the second operand
6923 is constant and the third is not or if the third operand is
6924 equivalent to the first operand of the comparison. */
6926 if (integer_zerop (arg1)
6927 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
6928 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6929 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6930 TREE_OPERAND (t, 2),
6931 TREE_OPERAND (arg0, 1))))
6933 /* See if this can be inverted. If it can't, possibly because
6934 it was a floating-point inequality comparison, don't do
6936 tem = invert_truthvalue (arg0);
6938 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
6940 t = build (code, type, tem,
6941 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
6943 /* arg1 should be the first argument of the new T. */
6944 arg1 = TREE_OPERAND (t, 1);
6949 /* If we have A op B ? A : C, we may be able to convert this to a
6950 simpler expression, depending on the operation and the values
6951 of B and C. Signed zeros prevent all of these transformations,
6952 for reasons given above each one. */
6954 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6955 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6956 arg1, TREE_OPERAND (arg0, 1))
6957 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
6959 tree arg2 = TREE_OPERAND (t, 2);
6960 enum tree_code comp_code = TREE_CODE (arg0);
6964 /* If we have A op 0 ? A : -A, consider applying the following
6967 A == 0? A : -A same as -A
6968 A != 0? A : -A same as A
6969 A >= 0? A : -A same as abs (A)
6970 A > 0? A : -A same as abs (A)
6971 A <= 0? A : -A same as -abs (A)
6972 A < 0? A : -A same as -abs (A)
6974 None of these transformations work for modes with signed
6975 zeros. If A is +/-0, the first two transformations will
6976 change the sign of the result (from +0 to -0, or vice
6977 versa). The last four will fix the sign of the result,
6978 even though the original expressions could be positive or
6979 negative, depending on the sign of A.
6981 Note that all these transformations are correct if A is
6982 NaN, since the two alternatives (A and -A) are also NaNs. */
6983 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
6984 ? real_zerop (TREE_OPERAND (arg0, 1))
6985 : integer_zerop (TREE_OPERAND (arg0, 1)))
6986 && TREE_CODE (arg2) == NEGATE_EXPR
6987 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
6995 (convert (TREE_TYPE (TREE_OPERAND (t, 1)),
6998 return pedantic_non_lvalue (convert (type, arg1));
7001 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
7002 arg1 = convert ((*lang_hooks.types.signed_type)
7003 (TREE_TYPE (arg1)), arg1);
7004 return pedantic_non_lvalue
7005 (convert (type, fold (build1 (ABS_EXPR,
7006 TREE_TYPE (arg1), arg1))));
7009 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
7010 arg1 = convert ((lang_hooks.types.signed_type)
7011 (TREE_TYPE (arg1)), arg1);
7012 return pedantic_non_lvalue
7013 (negate_expr (convert (type,
7014 fold (build1 (ABS_EXPR,
7021 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
7022 A == 0 ? A : 0 is always 0 unless A is -0. Note that
7023 both transformations are correct when A is NaN: A != 0
7024 is then true, and A == 0 is false. */
7026 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
7028 if (comp_code == NE_EXPR)
7029 return pedantic_non_lvalue (convert (type, arg1));
7030 else if (comp_code == EQ_EXPR)
7031 return pedantic_non_lvalue (convert (type, integer_zero_node));
7034 /* Try some transformations of A op B ? A : B.
7036 A == B? A : B same as B
7037 A != B? A : B same as A
7038 A >= B? A : B same as max (A, B)
7039 A > B? A : B same as max (B, A)
7040 A <= B? A : B same as min (A, B)
7041 A < B? A : B same as min (B, A)
7043 As above, these transformations don't work in the presence
7044 of signed zeros. For example, if A and B are zeros of
7045 opposite sign, the first two transformations will change
7046 the sign of the result. In the last four, the original
7047 expressions give different results for (A=+0, B=-0) and
7048 (A=-0, B=+0), but the transformed expressions do not.
7050 The first two transformations are correct if either A or B
7051 is a NaN. In the first transformation, the condition will
7052 be false, and B will indeed be chosen. In the case of the
7053 second transformation, the condition A != B will be true,
7054 and A will be chosen.
7056 The conversions to max() and min() are not correct if B is
7057 a number and A is not. The conditions in the original
7058 expressions will be false, so all four give B. The min()
7059 and max() versions would give a NaN instead. */
7060 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
7061 arg2, TREE_OPERAND (arg0, 0)))
7063 tree comp_op0 = TREE_OPERAND (arg0, 0);
7064 tree comp_op1 = TREE_OPERAND (arg0, 1);
7065 tree comp_type = TREE_TYPE (comp_op0);
7067 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
7068 if (TYPE_MAIN_VARIANT (comp_type) == TYPE_MAIN_VARIANT (type))
7078 return pedantic_non_lvalue (convert (type, arg2));
7080 return pedantic_non_lvalue (convert (type, arg1));
7083 /* In C++ a ?: expression can be an lvalue, so put the
7084 operand which will be used if they are equal first
7085 so that we can convert this back to the
7086 corresponding COND_EXPR. */
7087 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))))
7088 return pedantic_non_lvalue
7089 (convert (type, fold (build (MIN_EXPR, comp_type,
7090 (comp_code == LE_EXPR
7091 ? comp_op0 : comp_op1),
7092 (comp_code == LE_EXPR
7093 ? comp_op1 : comp_op0)))));
7097 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))))
7098 return pedantic_non_lvalue
7099 (convert (type, fold (build (MAX_EXPR, comp_type,
7100 (comp_code == GE_EXPR
7101 ? comp_op0 : comp_op1),
7102 (comp_code == GE_EXPR
7103 ? comp_op1 : comp_op0)))));
7110 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
7111 we might still be able to simplify this. For example,
7112 if C1 is one less or one more than C2, this might have started
7113 out as a MIN or MAX and been transformed by this function.
7114 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
7116 if (INTEGRAL_TYPE_P (type)
7117 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
7118 && TREE_CODE (arg2) == INTEGER_CST)
7122 /* We can replace A with C1 in this case. */
7123 arg1 = convert (type, TREE_OPERAND (arg0, 1));
7124 t = build (code, type, TREE_OPERAND (t, 0), arg1,
7125 TREE_OPERAND (t, 2));
7129 /* If C1 is C2 + 1, this is min(A, C2). */
7130 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
7131 && operand_equal_p (TREE_OPERAND (arg0, 1),
7132 const_binop (PLUS_EXPR, arg2,
7133 integer_one_node, 0), 1))
7134 return pedantic_non_lvalue
7135 (fold (build (MIN_EXPR, type, arg1, arg2)));
7139 /* If C1 is C2 - 1, this is min(A, C2). */
7140 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
7141 && operand_equal_p (TREE_OPERAND (arg0, 1),
7142 const_binop (MINUS_EXPR, arg2,
7143 integer_one_node, 0), 1))
7144 return pedantic_non_lvalue
7145 (fold (build (MIN_EXPR, type, arg1, arg2)));
7149 /* If C1 is C2 - 1, this is max(A, C2). */
7150 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
7151 && operand_equal_p (TREE_OPERAND (arg0, 1),
7152 const_binop (MINUS_EXPR, arg2,
7153 integer_one_node, 0), 1))
7154 return pedantic_non_lvalue
7155 (fold (build (MAX_EXPR, type, arg1, arg2)));
7159 /* If C1 is C2 + 1, this is max(A, C2). */
7160 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
7161 && operand_equal_p (TREE_OPERAND (arg0, 1),
7162 const_binop (PLUS_EXPR, arg2,
7163 integer_one_node, 0), 1))
7164 return pedantic_non_lvalue
7165 (fold (build (MAX_EXPR, type, arg1, arg2)));
7174 /* If the second operand is simpler than the third, swap them
7175 since that produces better jump optimization results. */
7176 if ((TREE_CONSTANT (arg1) || DECL_P (arg1)
7177 || TREE_CODE (arg1) == SAVE_EXPR)
7178 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
7179 || DECL_P (TREE_OPERAND (t, 2))
7180 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
7182 /* See if this can be inverted. If it can't, possibly because
7183 it was a floating-point inequality comparison, don't do
7185 tem = invert_truthvalue (arg0);
7187 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
7189 t = build (code, type, tem,
7190 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
7192 /* arg1 should be the first argument of the new T. */
7193 arg1 = TREE_OPERAND (t, 1);
7198 /* Convert A ? 1 : 0 to simply A. */
7199 if (integer_onep (TREE_OPERAND (t, 1))
7200 && integer_zerop (TREE_OPERAND (t, 2))
7201 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
7202 call to fold will try to move the conversion inside
7203 a COND, which will recurse. In that case, the COND_EXPR
7204 is probably the best choice, so leave it alone. */
7205 && type == TREE_TYPE (arg0))
7206 return pedantic_non_lvalue (arg0);
7208 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
7209 over COND_EXPR in cases such as floating point comparisons. */
7210 if (integer_zerop (TREE_OPERAND (t, 1))
7211 && integer_onep (TREE_OPERAND (t, 2))
7212 && truth_value_p (TREE_CODE (arg0)))
7213 return pedantic_non_lvalue (convert (type,
7214 invert_truthvalue (arg0)));
7216 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
7217 operation is simply A & 2. */
7219 if (integer_zerop (TREE_OPERAND (t, 2))
7220 && TREE_CODE (arg0) == NE_EXPR
7221 && integer_zerop (TREE_OPERAND (arg0, 1))
7222 && integer_pow2p (arg1)
7223 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
7224 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
7226 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
7228 /* Convert A ? B : 0 into A && B if A and B are truth values. */
7229 if (integer_zerop (TREE_OPERAND (t, 2))
7230 && truth_value_p (TREE_CODE (arg0))
7231 && truth_value_p (TREE_CODE (arg1)))
7232 return pedantic_non_lvalue (fold (build (TRUTH_ANDIF_EXPR, type,
7235 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
7236 if (integer_onep (TREE_OPERAND (t, 2))
7237 && truth_value_p (TREE_CODE (arg0))
7238 && truth_value_p (TREE_CODE (arg1)))
7240 /* Only perform transformation if ARG0 is easily inverted. */
7241 tem = invert_truthvalue (arg0);
7242 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
7243 return pedantic_non_lvalue (fold (build (TRUTH_ORIF_EXPR, type,
7250 /* When pedantic, a compound expression can be neither an lvalue
7251 nor an integer constant expression. */
7252 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
7254 /* Don't let (0, 0) be null pointer constant. */
7255 if (integer_zerop (arg1))
7256 return build1 (NOP_EXPR, type, arg1);
7257 return convert (type, arg1);
7261 return build_complex (type, arg0, arg1);
7265 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
7267 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
7268 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
7269 TREE_OPERAND (arg0, 1));
7270 else if (TREE_CODE (arg0) == COMPLEX_CST)
7271 return TREE_REALPART (arg0);
7272 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
7273 return fold (build (TREE_CODE (arg0), type,
7274 fold (build1 (REALPART_EXPR, type,
7275 TREE_OPERAND (arg0, 0))),
7276 fold (build1 (REALPART_EXPR,
7277 type, TREE_OPERAND (arg0, 1)))));
7281 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
7282 return convert (type, integer_zero_node);
7283 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
7284 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
7285 TREE_OPERAND (arg0, 0));
7286 else if (TREE_CODE (arg0) == COMPLEX_CST)
7287 return TREE_IMAGPART (arg0);
7288 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
7289 return fold (build (TREE_CODE (arg0), type,
7290 fold (build1 (IMAGPART_EXPR, type,
7291 TREE_OPERAND (arg0, 0))),
7292 fold (build1 (IMAGPART_EXPR, type,
7293 TREE_OPERAND (arg0, 1)))));
7296 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
7298 case CLEANUP_POINT_EXPR:
7299 if (! has_cleanups (arg0))
7300 return TREE_OPERAND (t, 0);
7303 enum tree_code code0 = TREE_CODE (arg0);
7304 int kind0 = TREE_CODE_CLASS (code0);
7305 tree arg00 = TREE_OPERAND (arg0, 0);
7308 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
7309 return fold (build1 (code0, type,
7310 fold (build1 (CLEANUP_POINT_EXPR,
7311 TREE_TYPE (arg00), arg00))));
7313 if (kind0 == '<' || kind0 == '2'
7314 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
7315 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
7316 || code0 == TRUTH_XOR_EXPR)
7318 arg01 = TREE_OPERAND (arg0, 1);
7320 if (TREE_CONSTANT (arg00)
7321 || ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
7322 && ! has_cleanups (arg00)))
7323 return fold (build (code0, type, arg00,
7324 fold (build1 (CLEANUP_POINT_EXPR,
7325 TREE_TYPE (arg01), arg01))));
7327 if (TREE_CONSTANT (arg01))
7328 return fold (build (code0, type,
7329 fold (build1 (CLEANUP_POINT_EXPR,
7330 TREE_TYPE (arg00), arg00)),
7338 /* Check for a built-in function. */
7339 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR
7340 && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (expr, 0), 0))
7342 && DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (expr, 0), 0)))
7344 tree tmp = fold_builtin (expr);
7352 } /* switch (code) */
7355 /* Determine if first argument is a multiple of second argument. Return 0 if
7356 it is not, or we cannot easily determined it to be.
7358 An example of the sort of thing we care about (at this point; this routine
7359 could surely be made more general, and expanded to do what the *_DIV_EXPR's
7360 fold cases do now) is discovering that
7362 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
7368 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
7370 This code also handles discovering that
7372 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
7374 is a multiple of 8 so we don't have to worry about dealing with a
7377 Note that we *look* inside a SAVE_EXPR only to determine how it was
7378 calculated; it is not safe for fold to do much of anything else with the
7379 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
7380 at run time. For example, the latter example above *cannot* be implemented
7381 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
7382 evaluation time of the original SAVE_EXPR is not necessarily the same at
7383 the time the new expression is evaluated. The only optimization of this
7384 sort that would be valid is changing
7386 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
7390 SAVE_EXPR (I) * SAVE_EXPR (J)
7392 (where the same SAVE_EXPR (J) is used in the original and the
7393 transformed version). */
7396 multiple_of_p (type, top, bottom)
7401 if (operand_equal_p (top, bottom, 0))
7404 if (TREE_CODE (type) != INTEGER_TYPE)
7407 switch (TREE_CODE (top))
7410 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
7411 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
7415 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
7416 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
7419 if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST)
7423 op1 = TREE_OPERAND (top, 1);
7424 /* const_binop may not detect overflow correctly,
7425 so check for it explicitly here. */
7426 if (TYPE_PRECISION (TREE_TYPE (size_one_node))
7427 > TREE_INT_CST_LOW (op1)
7428 && TREE_INT_CST_HIGH (op1) == 0
7429 && 0 != (t1 = convert (type,
7430 const_binop (LSHIFT_EXPR, size_one_node,
7432 && ! TREE_OVERFLOW (t1))
7433 return multiple_of_p (type, t1, bottom);
7438 /* Can't handle conversions from non-integral or wider integral type. */
7439 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
7440 || (TYPE_PRECISION (type)
7441 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
7444 /* .. fall through ... */
7447 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
7450 if (TREE_CODE (bottom) != INTEGER_CST
7451 || (TREE_UNSIGNED (type)
7452 && (tree_int_cst_sgn (top) < 0
7453 || tree_int_cst_sgn (bottom) < 0)))
7455 return integer_zerop (const_binop (TRUNC_MOD_EXPR,
7463 /* Return true if `t' is known to be non-negative. */
7466 tree_expr_nonnegative_p (t)
7469 switch (TREE_CODE (t))
7479 /* These are undefined at zero. This is true even if
7480 C[LT]Z_DEFINED_VALUE_AT_ZERO is set, since what we're
7481 computing here is a user-visible property. */
7485 return tree_int_cst_sgn (t) >= 0;
7486 case TRUNC_DIV_EXPR:
7488 case FLOOR_DIV_EXPR:
7489 case ROUND_DIV_EXPR:
7490 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7491 && tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7492 case TRUNC_MOD_EXPR:
7494 case FLOOR_MOD_EXPR:
7495 case ROUND_MOD_EXPR:
7496 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7498 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
7499 && tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
7501 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7503 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7504 && tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7506 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7507 || tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7509 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7511 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7513 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7514 case NON_LVALUE_EXPR:
7515 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7517 return rtl_expr_nonnegative_p (RTL_EXPR_RTL (t));
7520 if (truth_value_p (TREE_CODE (t)))
7521 /* Truth values evaluate to 0 or 1, which is nonnegative. */
7524 /* We don't know sign of `t', so be conservative and return false. */
7529 /* Return true if `r' is known to be non-negative.
7530 Only handles constants at the moment. */
7533 rtl_expr_nonnegative_p (r)
7536 switch (GET_CODE (r))
7539 return INTVAL (r) >= 0;
7542 if (GET_MODE (r) == VOIDmode)
7543 return CONST_DOUBLE_HIGH (r) >= 0;
7551 units = CONST_VECTOR_NUNITS (r);
7553 for (i = 0; i < units; ++i)
7555 elt = CONST_VECTOR_ELT (r, i);
7556 if (!rtl_expr_nonnegative_p (elt))
7565 /* These are always nonnegative. */
7573 #include "gt-fold-const.h"