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. */
56 #include "langhooks.h"
58 static void encode PARAMS ((HOST_WIDE_INT *,
59 unsigned HOST_WIDE_INT,
61 static void decode PARAMS ((HOST_WIDE_INT *,
62 unsigned HOST_WIDE_INT *,
64 static tree negate_expr PARAMS ((tree));
65 static tree split_tree PARAMS ((tree, enum tree_code, tree *, tree *,
67 static tree associate_trees PARAMS ((tree, tree, enum tree_code, tree));
68 static tree int_const_binop PARAMS ((enum tree_code, tree, tree, int));
69 static tree const_binop PARAMS ((enum tree_code, tree, tree, int));
70 static hashval_t size_htab_hash PARAMS ((const void *));
71 static int size_htab_eq PARAMS ((const void *, const void *));
72 static tree fold_convert PARAMS ((tree, tree));
73 static enum tree_code invert_tree_comparison PARAMS ((enum tree_code));
74 static enum tree_code swap_tree_comparison PARAMS ((enum tree_code));
75 static int comparison_to_compcode PARAMS ((enum tree_code));
76 static enum tree_code compcode_to_comparison PARAMS ((int));
77 static int truth_value_p PARAMS ((enum tree_code));
78 static int operand_equal_for_comparison_p PARAMS ((tree, tree, tree));
79 static int twoval_comparison_p PARAMS ((tree, tree *, tree *, int *));
80 static tree eval_subst PARAMS ((tree, tree, tree, tree, tree));
81 static tree omit_one_operand PARAMS ((tree, tree, tree));
82 static tree pedantic_omit_one_operand PARAMS ((tree, tree, tree));
83 static tree distribute_bit_expr PARAMS ((enum tree_code, tree, tree, tree));
84 static tree make_bit_field_ref PARAMS ((tree, tree, int, int, int));
85 static tree optimize_bit_field_compare PARAMS ((enum tree_code, tree,
87 static tree decode_field_reference PARAMS ((tree, HOST_WIDE_INT *,
89 enum machine_mode *, int *,
90 int *, tree *, tree *));
91 static int all_ones_mask_p PARAMS ((tree, int));
92 static tree sign_bit_p PARAMS ((tree, tree));
93 static int simple_operand_p PARAMS ((tree));
94 static tree range_binop PARAMS ((enum tree_code, tree, tree, int,
96 static tree make_range PARAMS ((tree, int *, tree *, tree *));
97 static tree build_range_check PARAMS ((tree, tree, int, tree, tree));
98 static int merge_ranges PARAMS ((int *, tree *, tree *, int, tree, tree,
100 static tree fold_range_test PARAMS ((tree));
101 static tree unextend PARAMS ((tree, int, int, tree));
102 static tree fold_truthop PARAMS ((enum tree_code, tree, tree, tree));
103 static tree optimize_minmax_comparison PARAMS ((tree));
104 static tree extract_muldiv PARAMS ((tree, tree, enum tree_code, tree));
105 static tree strip_compound_expr PARAMS ((tree, tree));
106 static int multiple_of_p PARAMS ((tree, tree, tree));
107 static tree constant_boolean_node PARAMS ((int, tree));
108 static int count_cond PARAMS ((tree, int));
109 static tree fold_binary_op_with_conditional_arg
110 PARAMS ((enum tree_code, tree, tree, tree, int));
111 static bool fold_real_zero_addition_p PARAMS ((tree, tree, int));
113 /* The following constants represent a bit based encoding of GCC's
114 comparison operators. This encoding simplifies transformations
115 on relational comparison operators, such as AND and OR. */
116 #define COMPCODE_FALSE 0
117 #define COMPCODE_LT 1
118 #define COMPCODE_EQ 2
119 #define COMPCODE_LE 3
120 #define COMPCODE_GT 4
121 #define COMPCODE_NE 5
122 #define COMPCODE_GE 6
123 #define COMPCODE_TRUE 7
125 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
126 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
127 and SUM1. Then this yields nonzero if overflow occurred during the
130 Overflow occurs if A and B have the same sign, but A and SUM differ in
131 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
133 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
135 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
136 We do that by representing the two-word integer in 4 words, with only
137 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
138 number. The value of the word is LOWPART + HIGHPART * BASE. */
141 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
142 #define HIGHPART(x) \
143 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
144 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
146 /* Unpack a two-word integer into 4 words.
147 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
148 WORDS points to the array of HOST_WIDE_INTs. */
151 encode (words, low, hi)
152 HOST_WIDE_INT *words;
153 unsigned HOST_WIDE_INT low;
156 words[0] = LOWPART (low);
157 words[1] = HIGHPART (low);
158 words[2] = LOWPART (hi);
159 words[3] = HIGHPART (hi);
162 /* Pack an array of 4 words into a two-word integer.
163 WORDS points to the array of words.
164 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
167 decode (words, low, hi)
168 HOST_WIDE_INT *words;
169 unsigned HOST_WIDE_INT *low;
172 *low = words[0] + words[1] * BASE;
173 *hi = words[2] + words[3] * BASE;
176 /* Make the integer constant T valid for its type by setting to 0 or 1 all
177 the bits in the constant that don't belong in the type.
179 Return 1 if a signed overflow occurs, 0 otherwise. If OVERFLOW is
180 nonzero, a signed overflow has already occurred in calculating T, so
184 force_fit_type (t, overflow)
188 unsigned HOST_WIDE_INT low;
192 if (TREE_CODE (t) == REAL_CST)
194 /* ??? Used to check for overflow here via CHECK_FLOAT_TYPE.
195 Consider doing it via real_convert now. */
199 else if (TREE_CODE (t) != INTEGER_CST)
202 low = TREE_INT_CST_LOW (t);
203 high = TREE_INT_CST_HIGH (t);
205 if (POINTER_TYPE_P (TREE_TYPE (t)))
208 prec = TYPE_PRECISION (TREE_TYPE (t));
210 /* First clear all bits that are beyond the type's precision. */
212 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
214 else if (prec > HOST_BITS_PER_WIDE_INT)
215 TREE_INT_CST_HIGH (t)
216 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
219 TREE_INT_CST_HIGH (t) = 0;
220 if (prec < HOST_BITS_PER_WIDE_INT)
221 TREE_INT_CST_LOW (t) &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
224 /* Unsigned types do not suffer sign extension or overflow unless they
226 if (TREE_UNSIGNED (TREE_TYPE (t))
227 && ! (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
228 && TYPE_IS_SIZETYPE (TREE_TYPE (t))))
231 /* If the value's sign bit is set, extend the sign. */
232 if (prec != 2 * HOST_BITS_PER_WIDE_INT
233 && (prec > HOST_BITS_PER_WIDE_INT
234 ? 0 != (TREE_INT_CST_HIGH (t)
236 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
237 : 0 != (TREE_INT_CST_LOW (t)
238 & ((unsigned HOST_WIDE_INT) 1 << (prec - 1)))))
240 /* Value is negative:
241 set to 1 all the bits that are outside this type's precision. */
242 if (prec > HOST_BITS_PER_WIDE_INT)
243 TREE_INT_CST_HIGH (t)
244 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
247 TREE_INT_CST_HIGH (t) = -1;
248 if (prec < HOST_BITS_PER_WIDE_INT)
249 TREE_INT_CST_LOW (t) |= ((unsigned HOST_WIDE_INT) (-1) << prec);
253 /* Return nonzero if signed overflow occurred. */
255 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
259 /* Add two doubleword integers with doubleword result.
260 Each argument is given as two `HOST_WIDE_INT' pieces.
261 One argument is L1 and H1; the other, L2 and H2.
262 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
265 add_double (l1, h1, l2, h2, lv, hv)
266 unsigned HOST_WIDE_INT l1, l2;
267 HOST_WIDE_INT h1, h2;
268 unsigned HOST_WIDE_INT *lv;
271 unsigned HOST_WIDE_INT l;
275 h = h1 + h2 + (l < l1);
279 return OVERFLOW_SUM_SIGN (h1, h2, h);
282 /* Negate a doubleword integer with doubleword result.
283 Return nonzero if the operation overflows, assuming it's signed.
284 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
285 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
288 neg_double (l1, h1, lv, hv)
289 unsigned HOST_WIDE_INT l1;
291 unsigned HOST_WIDE_INT *lv;
298 return (*hv & h1) < 0;
308 /* Multiply two doubleword integers with doubleword result.
309 Return nonzero if the operation overflows, assuming it's signed.
310 Each argument is given as two `HOST_WIDE_INT' pieces.
311 One argument is L1 and H1; the other, L2 and H2.
312 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
315 mul_double (l1, h1, l2, h2, lv, hv)
316 unsigned HOST_WIDE_INT l1, l2;
317 HOST_WIDE_INT h1, h2;
318 unsigned HOST_WIDE_INT *lv;
321 HOST_WIDE_INT arg1[4];
322 HOST_WIDE_INT arg2[4];
323 HOST_WIDE_INT prod[4 * 2];
324 unsigned HOST_WIDE_INT carry;
326 unsigned HOST_WIDE_INT toplow, neglow;
327 HOST_WIDE_INT tophigh, neghigh;
329 encode (arg1, l1, h1);
330 encode (arg2, l2, h2);
332 memset ((char *) prod, 0, sizeof prod);
334 for (i = 0; i < 4; i++)
337 for (j = 0; j < 4; j++)
340 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
341 carry += arg1[i] * arg2[j];
342 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
344 prod[k] = LOWPART (carry);
345 carry = HIGHPART (carry);
350 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
352 /* Check for overflow by calculating the top half of the answer in full;
353 it should agree with the low half's sign bit. */
354 decode (prod + 4, &toplow, &tophigh);
357 neg_double (l2, h2, &neglow, &neghigh);
358 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
362 neg_double (l1, h1, &neglow, &neghigh);
363 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
365 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
368 /* Shift the doubleword integer in L1, H1 left by COUNT places
369 keeping only PREC bits of result.
370 Shift right if COUNT is negative.
371 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
372 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
375 lshift_double (l1, h1, count, prec, lv, hv, arith)
376 unsigned HOST_WIDE_INT l1;
377 HOST_WIDE_INT h1, count;
379 unsigned HOST_WIDE_INT *lv;
383 unsigned HOST_WIDE_INT signmask;
387 rshift_double (l1, h1, -count, prec, lv, hv, arith);
391 #ifdef SHIFT_COUNT_TRUNCATED
392 if (SHIFT_COUNT_TRUNCATED)
396 if (count >= 2 * HOST_BITS_PER_WIDE_INT)
398 /* Shifting by the host word size is undefined according to the
399 ANSI standard, so we must handle this as a special case. */
403 else if (count >= HOST_BITS_PER_WIDE_INT)
405 *hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
410 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
411 | (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
415 /* Sign extend all bits that are beyond the precision. */
417 signmask = -((prec > HOST_BITS_PER_WIDE_INT
418 ? ((unsigned HOST_WIDE_INT) *hv
419 >> (prec - HOST_BITS_PER_WIDE_INT - 1))
420 : (*lv >> (prec - 1))) & 1);
422 if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
424 else if (prec >= HOST_BITS_PER_WIDE_INT)
426 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
427 *hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT);
432 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
433 *lv |= signmask << prec;
437 /* Shift the doubleword integer in L1, H1 right by COUNT places
438 keeping only PREC bits of result. COUNT must be positive.
439 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
440 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
443 rshift_double (l1, h1, count, prec, lv, hv, arith)
444 unsigned HOST_WIDE_INT l1;
445 HOST_WIDE_INT h1, count;
447 unsigned HOST_WIDE_INT *lv;
451 unsigned HOST_WIDE_INT signmask;
454 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
457 #ifdef SHIFT_COUNT_TRUNCATED
458 if (SHIFT_COUNT_TRUNCATED)
462 if (count >= 2 * HOST_BITS_PER_WIDE_INT)
464 /* Shifting by the host word size is undefined according to the
465 ANSI standard, so we must handle this as a special case. */
469 else if (count >= HOST_BITS_PER_WIDE_INT)
472 *lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT);
476 *hv = (unsigned HOST_WIDE_INT) h1 >> count;
478 | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
481 /* Zero / sign extend all bits that are beyond the precision. */
483 if (count >= (HOST_WIDE_INT)prec)
488 else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT)
490 else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
492 *hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT));
493 *hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
498 *lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count));
499 *lv |= signmask << (prec - count);
503 /* Rotate the doubleword integer in L1, H1 left by COUNT places
504 keeping only PREC bits of result.
505 Rotate right if COUNT is negative.
506 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
509 lrotate_double (l1, h1, count, prec, lv, hv)
510 unsigned HOST_WIDE_INT l1;
511 HOST_WIDE_INT h1, count;
513 unsigned HOST_WIDE_INT *lv;
516 unsigned HOST_WIDE_INT s1l, s2l;
517 HOST_WIDE_INT s1h, s2h;
523 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
524 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
529 /* Rotate the doubleword integer in L1, H1 left by COUNT places
530 keeping only PREC bits of result. COUNT must be positive.
531 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
534 rrotate_double (l1, h1, count, prec, lv, hv)
535 unsigned HOST_WIDE_INT l1;
536 HOST_WIDE_INT h1, count;
538 unsigned HOST_WIDE_INT *lv;
541 unsigned HOST_WIDE_INT s1l, s2l;
542 HOST_WIDE_INT s1h, s2h;
548 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
549 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
554 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
555 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
556 CODE is a tree code for a kind of division, one of
557 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
559 It controls how the quotient is rounded to an integer.
560 Return nonzero if the operation overflows.
561 UNS nonzero says do unsigned division. */
564 div_and_round_double (code, uns,
565 lnum_orig, hnum_orig, lden_orig, hden_orig,
566 lquo, hquo, lrem, hrem)
569 unsigned HOST_WIDE_INT lnum_orig; /* num == numerator == dividend */
570 HOST_WIDE_INT hnum_orig;
571 unsigned HOST_WIDE_INT lden_orig; /* den == denominator == divisor */
572 HOST_WIDE_INT hden_orig;
573 unsigned HOST_WIDE_INT *lquo, *lrem;
574 HOST_WIDE_INT *hquo, *hrem;
577 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
578 HOST_WIDE_INT den[4], quo[4];
580 unsigned HOST_WIDE_INT work;
581 unsigned HOST_WIDE_INT carry = 0;
582 unsigned HOST_WIDE_INT lnum = lnum_orig;
583 HOST_WIDE_INT hnum = hnum_orig;
584 unsigned HOST_WIDE_INT lden = lden_orig;
585 HOST_WIDE_INT hden = hden_orig;
588 if (hden == 0 && lden == 0)
589 overflow = 1, lden = 1;
591 /* calculate quotient sign and convert operands to unsigned. */
597 /* (minimum integer) / (-1) is the only overflow case. */
598 if (neg_double (lnum, hnum, &lnum, &hnum)
599 && ((HOST_WIDE_INT) lden & hden) == -1)
605 neg_double (lden, hden, &lden, &hden);
609 if (hnum == 0 && hden == 0)
610 { /* single precision */
612 /* This unsigned division rounds toward zero. */
618 { /* trivial case: dividend < divisor */
619 /* hden != 0 already checked. */
626 memset ((char *) quo, 0, sizeof quo);
628 memset ((char *) num, 0, sizeof num); /* to zero 9th element */
629 memset ((char *) den, 0, sizeof den);
631 encode (num, lnum, hnum);
632 encode (den, lden, hden);
634 /* Special code for when the divisor < BASE. */
635 if (hden == 0 && lden < (unsigned HOST_WIDE_INT) BASE)
637 /* hnum != 0 already checked. */
638 for (i = 4 - 1; i >= 0; i--)
640 work = num[i] + carry * BASE;
641 quo[i] = work / lden;
647 /* Full double precision division,
648 with thanks to Don Knuth's "Seminumerical Algorithms". */
649 int num_hi_sig, den_hi_sig;
650 unsigned HOST_WIDE_INT quo_est, scale;
652 /* Find the highest nonzero divisor digit. */
653 for (i = 4 - 1;; i--)
660 /* Insure that the first digit of the divisor is at least BASE/2.
661 This is required by the quotient digit estimation algorithm. */
663 scale = BASE / (den[den_hi_sig] + 1);
665 { /* scale divisor and dividend */
667 for (i = 0; i <= 4 - 1; i++)
669 work = (num[i] * scale) + carry;
670 num[i] = LOWPART (work);
671 carry = HIGHPART (work);
676 for (i = 0; i <= 4 - 1; i++)
678 work = (den[i] * scale) + carry;
679 den[i] = LOWPART (work);
680 carry = HIGHPART (work);
681 if (den[i] != 0) den_hi_sig = i;
688 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--)
690 /* Guess the next quotient digit, quo_est, by dividing the first
691 two remaining dividend digits by the high order quotient digit.
692 quo_est is never low and is at most 2 high. */
693 unsigned HOST_WIDE_INT tmp;
695 num_hi_sig = i + den_hi_sig + 1;
696 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
697 if (num[num_hi_sig] != den[den_hi_sig])
698 quo_est = work / den[den_hi_sig];
702 /* Refine quo_est so it's usually correct, and at most one high. */
703 tmp = work - quo_est * den[den_hi_sig];
705 && (den[den_hi_sig - 1] * quo_est
706 > (tmp * BASE + num[num_hi_sig - 2])))
709 /* Try QUO_EST as the quotient digit, by multiplying the
710 divisor by QUO_EST and subtracting from the remaining dividend.
711 Keep in mind that QUO_EST is the I - 1st digit. */
714 for (j = 0; j <= den_hi_sig; j++)
716 work = quo_est * den[j] + carry;
717 carry = HIGHPART (work);
718 work = num[i + j] - LOWPART (work);
719 num[i + j] = LOWPART (work);
720 carry += HIGHPART (work) != 0;
723 /* If quo_est was high by one, then num[i] went negative and
724 we need to correct things. */
725 if (num[num_hi_sig] < (HOST_WIDE_INT) carry)
728 carry = 0; /* add divisor back in */
729 for (j = 0; j <= den_hi_sig; j++)
731 work = num[i + j] + den[j] + carry;
732 carry = HIGHPART (work);
733 num[i + j] = LOWPART (work);
736 num [num_hi_sig] += carry;
739 /* Store the quotient digit. */
744 decode (quo, lquo, hquo);
747 /* if result is negative, make it so. */
749 neg_double (*lquo, *hquo, lquo, hquo);
751 /* compute trial remainder: rem = num - (quo * den) */
752 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
753 neg_double (*lrem, *hrem, lrem, hrem);
754 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
759 case TRUNC_MOD_EXPR: /* round toward zero */
760 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
764 case FLOOR_MOD_EXPR: /* round toward negative infinity */
765 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
768 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
776 case CEIL_MOD_EXPR: /* round toward positive infinity */
777 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
779 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
787 case ROUND_MOD_EXPR: /* round to closest integer */
789 unsigned HOST_WIDE_INT labs_rem = *lrem;
790 HOST_WIDE_INT habs_rem = *hrem;
791 unsigned HOST_WIDE_INT labs_den = lden, ltwice;
792 HOST_WIDE_INT habs_den = hden, htwice;
794 /* Get absolute values */
796 neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
798 neg_double (lden, hden, &labs_den, &habs_den);
800 /* If (2 * abs (lrem) >= abs (lden)) */
801 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
802 labs_rem, habs_rem, <wice, &htwice);
804 if (((unsigned HOST_WIDE_INT) habs_den
805 < (unsigned HOST_WIDE_INT) htwice)
806 || (((unsigned HOST_WIDE_INT) habs_den
807 == (unsigned HOST_WIDE_INT) htwice)
808 && (labs_den < ltwice)))
812 add_double (*lquo, *hquo,
813 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
816 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
828 /* compute true remainder: rem = num - (quo * den) */
829 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
830 neg_double (*lrem, *hrem, lrem, hrem);
831 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
835 /* Given T, an expression, return the negation of T. Allow for T to be
836 null, in which case return null. */
848 type = TREE_TYPE (t);
851 switch (TREE_CODE (t))
855 if (! TREE_UNSIGNED (type)
856 && 0 != (tem = fold (build1 (NEGATE_EXPR, type, t)))
857 && ! TREE_OVERFLOW (tem))
862 return convert (type, TREE_OPERAND (t, 0));
865 /* - (A - B) -> B - A */
866 if (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
867 return convert (type,
868 fold (build (MINUS_EXPR, TREE_TYPE (t),
870 TREE_OPERAND (t, 0))));
877 return convert (type, fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t)));
880 /* Split a tree IN into a constant, literal and variable parts that could be
881 combined with CODE to make IN. "constant" means an expression with
882 TREE_CONSTANT but that isn't an actual constant. CODE must be a
883 commutative arithmetic operation. Store the constant part into *CONP,
884 the literal in *LITP and return the variable part. If a part isn't
885 present, set it to null. If the tree does not decompose in this way,
886 return the entire tree as the variable part and the other parts as null.
888 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
889 case, we negate an operand that was subtracted. Except if it is a
890 literal for which we use *MINUS_LITP instead.
892 If NEGATE_P is true, we are negating all of IN, again except a literal
893 for which we use *MINUS_LITP instead.
895 If IN is itself a literal or constant, return it as appropriate.
897 Note that we do not guarantee that any of the three values will be the
898 same type as IN, but they will have the same signedness and mode. */
901 split_tree (in, code, conp, litp, minus_litp, negate_p)
904 tree *conp, *litp, *minus_litp;
913 /* Strip any conversions that don't change the machine mode or signedness. */
914 STRIP_SIGN_NOPS (in);
916 if (TREE_CODE (in) == INTEGER_CST || TREE_CODE (in) == REAL_CST)
918 else if (TREE_CODE (in) == code
919 || (! FLOAT_TYPE_P (TREE_TYPE (in))
920 /* We can associate addition and subtraction together (even
921 though the C standard doesn't say so) for integers because
922 the value is not affected. For reals, the value might be
923 affected, so we can't. */
924 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
925 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
927 tree op0 = TREE_OPERAND (in, 0);
928 tree op1 = TREE_OPERAND (in, 1);
929 int neg1_p = TREE_CODE (in) == MINUS_EXPR;
930 int neg_litp_p = 0, neg_conp_p = 0, neg_var_p = 0;
932 /* First see if either of the operands is a literal, then a constant. */
933 if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST)
934 *litp = op0, op0 = 0;
935 else if (TREE_CODE (op1) == INTEGER_CST || TREE_CODE (op1) == REAL_CST)
936 *litp = op1, neg_litp_p = neg1_p, op1 = 0;
938 if (op0 != 0 && TREE_CONSTANT (op0))
939 *conp = op0, op0 = 0;
940 else if (op1 != 0 && TREE_CONSTANT (op1))
941 *conp = op1, neg_conp_p = neg1_p, op1 = 0;
943 /* If we haven't dealt with either operand, this is not a case we can
944 decompose. Otherwise, VAR is either of the ones remaining, if any. */
945 if (op0 != 0 && op1 != 0)
950 var = op1, neg_var_p = neg1_p;
952 /* Now do any needed negations. */
954 *minus_litp = *litp, *litp = 0;
956 *conp = negate_expr (*conp);
958 var = negate_expr (var);
960 else if (TREE_CONSTANT (in))
968 *minus_litp = *litp, *litp = 0;
969 else if (*minus_litp)
970 *litp = *minus_litp, *minus_litp = 0;
971 *conp = negate_expr (*conp);
972 var = negate_expr (var);
978 /* Re-associate trees split by the above function. T1 and T2 are either
979 expressions to associate or null. Return the new expression, if any. If
980 we build an operation, do it in TYPE and with CODE. */
983 associate_trees (t1, t2, code, type)
993 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
994 try to fold this since we will have infinite recursion. But do
995 deal with any NEGATE_EXPRs. */
996 if (TREE_CODE (t1) == code || TREE_CODE (t2) == code
997 || TREE_CODE (t1) == MINUS_EXPR || TREE_CODE (t2) == MINUS_EXPR)
999 if (code == PLUS_EXPR)
1001 if (TREE_CODE (t1) == NEGATE_EXPR)
1002 return build (MINUS_EXPR, type, convert (type, t2),
1003 convert (type, TREE_OPERAND (t1, 0)));
1004 else if (TREE_CODE (t2) == NEGATE_EXPR)
1005 return build (MINUS_EXPR, type, convert (type, t1),
1006 convert (type, TREE_OPERAND (t2, 0)));
1008 return build (code, type, convert (type, t1), convert (type, t2));
1011 return fold (build (code, type, convert (type, t1), convert (type, t2)));
1014 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1015 to produce a new constant.
1017 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1020 int_const_binop (code, arg1, arg2, notrunc)
1021 enum tree_code code;
1025 unsigned HOST_WIDE_INT int1l, int2l;
1026 HOST_WIDE_INT int1h, int2h;
1027 unsigned HOST_WIDE_INT low;
1029 unsigned HOST_WIDE_INT garbagel;
1030 HOST_WIDE_INT garbageh;
1032 tree type = TREE_TYPE (arg1);
1033 int uns = TREE_UNSIGNED (type);
1035 = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type));
1037 int no_overflow = 0;
1039 int1l = TREE_INT_CST_LOW (arg1);
1040 int1h = TREE_INT_CST_HIGH (arg1);
1041 int2l = TREE_INT_CST_LOW (arg2);
1042 int2h = TREE_INT_CST_HIGH (arg2);
1047 low = int1l | int2l, hi = int1h | int2h;
1051 low = int1l ^ int2l, hi = int1h ^ int2h;
1055 low = int1l & int2l, hi = int1h & int2h;
1058 case BIT_ANDTC_EXPR:
1059 low = int1l & ~int2l, hi = int1h & ~int2h;
1065 /* It's unclear from the C standard whether shifts can overflow.
1066 The following code ignores overflow; perhaps a C standard
1067 interpretation ruling is needed. */
1068 lshift_double (int1l, int1h, int2l, TYPE_PRECISION (type),
1076 lrotate_double (int1l, int1h, int2l, TYPE_PRECISION (type),
1081 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1085 neg_double (int2l, int2h, &low, &hi);
1086 add_double (int1l, int1h, low, hi, &low, &hi);
1087 overflow = OVERFLOW_SUM_SIGN (hi, int2h, int1h);
1091 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1094 case TRUNC_DIV_EXPR:
1095 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1096 case EXACT_DIV_EXPR:
1097 /* This is a shortcut for a common special case. */
1098 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
1099 && ! TREE_CONSTANT_OVERFLOW (arg1)
1100 && ! TREE_CONSTANT_OVERFLOW (arg2)
1101 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
1103 if (code == CEIL_DIV_EXPR)
1106 low = int1l / int2l, hi = 0;
1110 /* ... fall through ... */
1112 case ROUND_DIV_EXPR:
1113 if (int2h == 0 && int2l == 1)
1115 low = int1l, hi = int1h;
1118 if (int1l == int2l && int1h == int2h
1119 && ! (int1l == 0 && int1h == 0))
1124 overflow = div_and_round_double (code, uns, int1l, int1h, int2l, int2h,
1125 &low, &hi, &garbagel, &garbageh);
1128 case TRUNC_MOD_EXPR:
1129 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1130 /* This is a shortcut for a common special case. */
1131 if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
1132 && ! TREE_CONSTANT_OVERFLOW (arg1)
1133 && ! TREE_CONSTANT_OVERFLOW (arg2)
1134 && int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
1136 if (code == CEIL_MOD_EXPR)
1138 low = int1l % int2l, hi = 0;
1142 /* ... fall through ... */
1144 case ROUND_MOD_EXPR:
1145 overflow = div_and_round_double (code, uns,
1146 int1l, int1h, int2l, int2h,
1147 &garbagel, &garbageh, &low, &hi);
1153 low = (((unsigned HOST_WIDE_INT) int1h
1154 < (unsigned HOST_WIDE_INT) int2h)
1155 || (((unsigned HOST_WIDE_INT) int1h
1156 == (unsigned HOST_WIDE_INT) int2h)
1159 low = (int1h < int2h
1160 || (int1h == int2h && int1l < int2l));
1162 if (low == (code == MIN_EXPR))
1163 low = int1l, hi = int1h;
1165 low = int2l, hi = int2h;
1172 /* If this is for a sizetype, can be represented as one (signed)
1173 HOST_WIDE_INT word, and doesn't overflow, use size_int since it caches
1176 && ((hi == 0 && (HOST_WIDE_INT) low >= 0)
1177 || (hi == -1 && (HOST_WIDE_INT) low < 0))
1178 && overflow == 0 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1179 return size_int_type_wide (low, type);
1182 t = build_int_2 (low, hi);
1183 TREE_TYPE (t) = TREE_TYPE (arg1);
1188 ? (!uns || is_sizetype) && overflow
1189 : (force_fit_type (t, (!uns || is_sizetype) && overflow)
1191 | TREE_OVERFLOW (arg1)
1192 | TREE_OVERFLOW (arg2));
1194 /* If we're doing a size calculation, unsigned arithmetic does overflow.
1195 So check if force_fit_type truncated the value. */
1197 && ! TREE_OVERFLOW (t)
1198 && (TREE_INT_CST_HIGH (t) != hi
1199 || TREE_INT_CST_LOW (t) != low))
1200 TREE_OVERFLOW (t) = 1;
1202 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1203 | TREE_CONSTANT_OVERFLOW (arg1)
1204 | TREE_CONSTANT_OVERFLOW (arg2));
1208 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1209 constant. We assume ARG1 and ARG2 have the same data type, or at least
1210 are the same kind of constant and the same machine mode.
1212 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1215 const_binop (code, arg1, arg2, notrunc)
1216 enum tree_code code;
1223 if (TREE_CODE (arg1) == INTEGER_CST)
1224 return int_const_binop (code, arg1, arg2, notrunc);
1226 if (TREE_CODE (arg1) == REAL_CST)
1230 REAL_VALUE_TYPE value;
1233 d1 = TREE_REAL_CST (arg1);
1234 d2 = TREE_REAL_CST (arg2);
1236 /* If either operand is a NaN, just return it. Otherwise, set up
1237 for floating-point trap; we return an overflow. */
1238 if (REAL_VALUE_ISNAN (d1))
1240 else if (REAL_VALUE_ISNAN (d2))
1243 REAL_ARITHMETIC (value, code, d1, d2);
1245 t = build_real (TREE_TYPE (arg1),
1246 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)),
1250 = (force_fit_type (t, 0)
1251 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1252 TREE_CONSTANT_OVERFLOW (t)
1254 | TREE_CONSTANT_OVERFLOW (arg1)
1255 | TREE_CONSTANT_OVERFLOW (arg2);
1258 if (TREE_CODE (arg1) == COMPLEX_CST)
1260 tree type = TREE_TYPE (arg1);
1261 tree r1 = TREE_REALPART (arg1);
1262 tree i1 = TREE_IMAGPART (arg1);
1263 tree r2 = TREE_REALPART (arg2);
1264 tree i2 = TREE_IMAGPART (arg2);
1270 t = build_complex (type,
1271 const_binop (PLUS_EXPR, r1, r2, notrunc),
1272 const_binop (PLUS_EXPR, i1, i2, notrunc));
1276 t = build_complex (type,
1277 const_binop (MINUS_EXPR, r1, r2, notrunc),
1278 const_binop (MINUS_EXPR, i1, i2, notrunc));
1282 t = build_complex (type,
1283 const_binop (MINUS_EXPR,
1284 const_binop (MULT_EXPR,
1286 const_binop (MULT_EXPR,
1289 const_binop (PLUS_EXPR,
1290 const_binop (MULT_EXPR,
1292 const_binop (MULT_EXPR,
1300 = const_binop (PLUS_EXPR,
1301 const_binop (MULT_EXPR, r2, r2, notrunc),
1302 const_binop (MULT_EXPR, i2, i2, notrunc),
1305 t = build_complex (type,
1307 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1308 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1309 const_binop (PLUS_EXPR,
1310 const_binop (MULT_EXPR, r1, r2,
1312 const_binop (MULT_EXPR, i1, i2,
1315 magsquared, notrunc),
1317 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1318 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1319 const_binop (MINUS_EXPR,
1320 const_binop (MULT_EXPR, i1, r2,
1322 const_binop (MULT_EXPR, r1, i2,
1325 magsquared, notrunc));
1337 /* These are the hash table functions for the hash table of INTEGER_CST
1338 nodes of a sizetype. */
1340 /* Return the hash code code X, an INTEGER_CST. */
1348 return (TREE_INT_CST_HIGH (t) ^ TREE_INT_CST_LOW (t)
1349 ^ htab_hash_pointer (TREE_TYPE (t))
1350 ^ (TREE_OVERFLOW (t) << 20));
1353 /* Return nonzero if the value represented by *X (an INTEGER_CST tree node)
1354 is the same as that given by *Y, which is the same. */
1364 return (TREE_INT_CST_HIGH (xt) == TREE_INT_CST_HIGH (yt)
1365 && TREE_INT_CST_LOW (xt) == TREE_INT_CST_LOW (yt)
1366 && TREE_TYPE (xt) == TREE_TYPE (yt)
1367 && TREE_OVERFLOW (xt) == TREE_OVERFLOW (yt));
1370 /* Return an INTEGER_CST with value whose low-order HOST_BITS_PER_WIDE_INT
1371 bits are given by NUMBER and of the sizetype represented by KIND. */
1374 size_int_wide (number, kind)
1375 HOST_WIDE_INT number;
1376 enum size_type_kind kind;
1378 return size_int_type_wide (number, sizetype_tab[(int) kind]);
1381 /* Likewise, but the desired type is specified explicitly. */
1383 static GTY (()) tree new_const;
1384 static GTY ((if_marked ("ggc_marked_p"), param_is (union tree_node)))
1388 size_int_type_wide (number, type)
1389 HOST_WIDE_INT number;
1396 size_htab = htab_create (1024, size_htab_hash, size_htab_eq, NULL);
1397 new_const = make_node (INTEGER_CST);
1400 /* Adjust NEW_CONST to be the constant we want. If it's already in the
1401 hash table, we return the value from the hash table. Otherwise, we
1402 place that in the hash table and make a new node for the next time. */
1403 TREE_INT_CST_LOW (new_const) = number;
1404 TREE_INT_CST_HIGH (new_const) = number < 0 ? -1 : 0;
1405 TREE_TYPE (new_const) = type;
1406 TREE_OVERFLOW (new_const) = TREE_CONSTANT_OVERFLOW (new_const)
1407 = force_fit_type (new_const, 0);
1409 slot = htab_find_slot (size_htab, new_const, INSERT);
1414 *slot = (PTR) new_const;
1415 new_const = make_node (INTEGER_CST);
1419 return (tree) *slot;
1422 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1423 is a tree code. The type of the result is taken from the operands.
1424 Both must be the same type integer type and it must be a size type.
1425 If the operands are constant, so is the result. */
1428 size_binop (code, arg0, arg1)
1429 enum tree_code code;
1432 tree type = TREE_TYPE (arg0);
1434 if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
1435 || type != TREE_TYPE (arg1))
1438 /* Handle the special case of two integer constants faster. */
1439 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1441 /* And some specific cases even faster than that. */
1442 if (code == PLUS_EXPR && integer_zerop (arg0))
1444 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1445 && integer_zerop (arg1))
1447 else if (code == MULT_EXPR && integer_onep (arg0))
1450 /* Handle general case of two integer constants. */
1451 return int_const_binop (code, arg0, arg1, 0);
1454 if (arg0 == error_mark_node || arg1 == error_mark_node)
1455 return error_mark_node;
1457 return fold (build (code, type, arg0, arg1));
1460 /* Given two values, either both of sizetype or both of bitsizetype,
1461 compute the difference between the two values. Return the value
1462 in signed type corresponding to the type of the operands. */
1465 size_diffop (arg0, arg1)
1468 tree type = TREE_TYPE (arg0);
1471 if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
1472 || type != TREE_TYPE (arg1))
1475 /* If the type is already signed, just do the simple thing. */
1476 if (! TREE_UNSIGNED (type))
1477 return size_binop (MINUS_EXPR, arg0, arg1);
1479 ctype = (type == bitsizetype || type == ubitsizetype
1480 ? sbitsizetype : ssizetype);
1482 /* If either operand is not a constant, do the conversions to the signed
1483 type and subtract. The hardware will do the right thing with any
1484 overflow in the subtraction. */
1485 if (TREE_CODE (arg0) != INTEGER_CST || TREE_CODE (arg1) != INTEGER_CST)
1486 return size_binop (MINUS_EXPR, convert (ctype, arg0),
1487 convert (ctype, arg1));
1489 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1490 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1491 overflow) and negate (which can't either). Special-case a result
1492 of zero while we're here. */
1493 if (tree_int_cst_equal (arg0, arg1))
1494 return convert (ctype, integer_zero_node);
1495 else if (tree_int_cst_lt (arg1, arg0))
1496 return convert (ctype, size_binop (MINUS_EXPR, arg0, arg1));
1498 return size_binop (MINUS_EXPR, convert (ctype, integer_zero_node),
1499 convert (ctype, size_binop (MINUS_EXPR, arg1, arg0)));
1503 /* Given T, a tree representing type conversion of ARG1, a constant,
1504 return a constant tree representing the result of conversion. */
1507 fold_convert (t, arg1)
1511 tree type = TREE_TYPE (t);
1514 if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
1516 if (TREE_CODE (arg1) == INTEGER_CST)
1518 /* If we would build a constant wider than GCC supports,
1519 leave the conversion unfolded. */
1520 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1523 /* If we are trying to make a sizetype for a small integer, use
1524 size_int to pick up cached types to reduce duplicate nodes. */
1525 if (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)
1526 && !TREE_CONSTANT_OVERFLOW (arg1)
1527 && compare_tree_int (arg1, 10000) < 0)
1528 return size_int_type_wide (TREE_INT_CST_LOW (arg1), type);
1530 /* Given an integer constant, make new constant with new type,
1531 appropriately sign-extended or truncated. */
1532 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1533 TREE_INT_CST_HIGH (arg1));
1534 TREE_TYPE (t) = type;
1535 /* Indicate an overflow if (1) ARG1 already overflowed,
1536 or (2) force_fit_type indicates an overflow.
1537 Tell force_fit_type that an overflow has already occurred
1538 if ARG1 is a too-large unsigned value and T is signed.
1539 But don't indicate an overflow if converting a pointer. */
1541 = ((force_fit_type (t,
1542 (TREE_INT_CST_HIGH (arg1) < 0
1543 && (TREE_UNSIGNED (type)
1544 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1545 && ! POINTER_TYPE_P (TREE_TYPE (arg1)))
1546 || TREE_OVERFLOW (arg1));
1547 TREE_CONSTANT_OVERFLOW (t)
1548 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1550 else if (TREE_CODE (arg1) == REAL_CST)
1552 /* Don't initialize these, use assignments.
1553 Initialized local aggregates don't work on old compilers. */
1557 tree type1 = TREE_TYPE (arg1);
1560 x = TREE_REAL_CST (arg1);
1561 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1563 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1564 if (!no_upper_bound)
1565 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1567 /* See if X will be in range after truncation towards 0.
1568 To compensate for truncation, move the bounds away from 0,
1569 but reject if X exactly equals the adjusted bounds. */
1570 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1571 if (!no_upper_bound)
1572 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1573 /* If X is a NaN, use zero instead and show we have an overflow.
1574 Otherwise, range check. */
1575 if (REAL_VALUE_ISNAN (x))
1576 overflow = 1, x = dconst0;
1577 else if (! (REAL_VALUES_LESS (l, x)
1579 && REAL_VALUES_LESS (x, u)))
1583 HOST_WIDE_INT low, high;
1584 REAL_VALUE_TO_INT (&low, &high, x);
1585 t = build_int_2 (low, high);
1587 TREE_TYPE (t) = type;
1589 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1590 TREE_CONSTANT_OVERFLOW (t)
1591 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1593 TREE_TYPE (t) = type;
1595 else if (TREE_CODE (type) == REAL_TYPE)
1597 if (TREE_CODE (arg1) == INTEGER_CST)
1598 return build_real_from_int_cst (type, arg1);
1599 if (TREE_CODE (arg1) == REAL_CST)
1601 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1603 /* We make a copy of ARG1 so that we don't modify an
1604 existing constant tree. */
1605 t = copy_node (arg1);
1606 TREE_TYPE (t) = type;
1610 t = build_real (type,
1611 real_value_truncate (TYPE_MODE (type),
1612 TREE_REAL_CST (arg1)));
1615 = TREE_OVERFLOW (arg1) | force_fit_type (t, 0);
1616 TREE_CONSTANT_OVERFLOW (t)
1617 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1621 TREE_CONSTANT (t) = 1;
1625 /* Return an expr equal to X but certainly not valid as an lvalue. */
1633 /* These things are certainly not lvalues. */
1634 if (TREE_CODE (x) == NON_LVALUE_EXPR
1635 || TREE_CODE (x) == INTEGER_CST
1636 || TREE_CODE (x) == REAL_CST
1637 || TREE_CODE (x) == STRING_CST
1638 || TREE_CODE (x) == ADDR_EXPR)
1641 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1642 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1646 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1647 Zero means allow extended lvalues. */
1649 int pedantic_lvalues;
1651 /* When pedantic, return an expr equal to X but certainly not valid as a
1652 pedantic lvalue. Otherwise, return X. */
1655 pedantic_non_lvalue (x)
1658 if (pedantic_lvalues)
1659 return non_lvalue (x);
1664 /* Given a tree comparison code, return the code that is the logical inverse
1665 of the given code. It is not safe to do this for floating-point
1666 comparisons, except for NE_EXPR and EQ_EXPR. */
1668 static enum tree_code
1669 invert_tree_comparison (code)
1670 enum tree_code code;
1691 /* Similar, but return the comparison that results if the operands are
1692 swapped. This is safe for floating-point. */
1694 static enum tree_code
1695 swap_tree_comparison (code)
1696 enum tree_code code;
1717 /* Convert a comparison tree code from an enum tree_code representation
1718 into a compcode bit-based encoding. This function is the inverse of
1719 compcode_to_comparison. */
1722 comparison_to_compcode (code)
1723 enum tree_code code;
1744 /* Convert a compcode bit-based encoding of a comparison operator back
1745 to GCC's enum tree_code representation. This function is the
1746 inverse of comparison_to_compcode. */
1748 static enum tree_code
1749 compcode_to_comparison (code)
1771 /* Return nonzero if CODE is a tree code that represents a truth value. */
1774 truth_value_p (code)
1775 enum tree_code code;
1777 return (TREE_CODE_CLASS (code) == '<'
1778 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1779 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1780 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1783 /* Return nonzero if two operands are necessarily equal.
1784 If ONLY_CONST is nonzero, only return nonzero for constants.
1785 This function tests whether the operands are indistinguishable;
1786 it does not test whether they are equal using C's == operation.
1787 The distinction is important for IEEE floating point, because
1788 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1789 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1792 operand_equal_p (arg0, arg1, only_const)
1796 /* If both types don't have the same signedness, then we can't consider
1797 them equal. We must check this before the STRIP_NOPS calls
1798 because they may change the signedness of the arguments. */
1799 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1805 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1806 /* This is needed for conversions and for COMPONENT_REF.
1807 Might as well play it safe and always test this. */
1808 || TREE_CODE (TREE_TYPE (arg0)) == ERROR_MARK
1809 || TREE_CODE (TREE_TYPE (arg1)) == ERROR_MARK
1810 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1813 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1814 We don't care about side effects in that case because the SAVE_EXPR
1815 takes care of that for us. In all other cases, two expressions are
1816 equal if they have no side effects. If we have two identical
1817 expressions with side effects that should be treated the same due
1818 to the only side effects being identical SAVE_EXPR's, that will
1819 be detected in the recursive calls below. */
1820 if (arg0 == arg1 && ! only_const
1821 && (TREE_CODE (arg0) == SAVE_EXPR
1822 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1825 /* Next handle constant cases, those for which we can return 1 even
1826 if ONLY_CONST is set. */
1827 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1828 switch (TREE_CODE (arg0))
1831 return (! TREE_CONSTANT_OVERFLOW (arg0)
1832 && ! TREE_CONSTANT_OVERFLOW (arg1)
1833 && tree_int_cst_equal (arg0, arg1));
1836 return (! TREE_CONSTANT_OVERFLOW (arg0)
1837 && ! TREE_CONSTANT_OVERFLOW (arg1)
1838 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
1839 TREE_REAL_CST (arg1)));
1845 if (TREE_CONSTANT_OVERFLOW (arg0)
1846 || TREE_CONSTANT_OVERFLOW (arg1))
1849 v1 = TREE_VECTOR_CST_ELTS (arg0);
1850 v2 = TREE_VECTOR_CST_ELTS (arg1);
1853 if (!operand_equal_p (v1, v2, only_const))
1855 v1 = TREE_CHAIN (v1);
1856 v2 = TREE_CHAIN (v2);
1863 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1865 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1869 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1870 && ! memcmp (TREE_STRING_POINTER (arg0),
1871 TREE_STRING_POINTER (arg1),
1872 TREE_STRING_LENGTH (arg0)));
1875 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1884 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1887 /* Two conversions are equal only if signedness and modes match. */
1888 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1889 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1890 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1893 return operand_equal_p (TREE_OPERAND (arg0, 0),
1894 TREE_OPERAND (arg1, 0), 0);
1898 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1899 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1903 /* For commutative ops, allow the other order. */
1904 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1905 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1906 || TREE_CODE (arg0) == BIT_IOR_EXPR
1907 || TREE_CODE (arg0) == BIT_XOR_EXPR
1908 || TREE_CODE (arg0) == BIT_AND_EXPR
1909 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1910 && operand_equal_p (TREE_OPERAND (arg0, 0),
1911 TREE_OPERAND (arg1, 1), 0)
1912 && operand_equal_p (TREE_OPERAND (arg0, 1),
1913 TREE_OPERAND (arg1, 0), 0));
1916 /* If either of the pointer (or reference) expressions we are dereferencing
1917 contain a side effect, these cannot be equal. */
1918 if (TREE_SIDE_EFFECTS (arg0)
1919 || TREE_SIDE_EFFECTS (arg1))
1922 switch (TREE_CODE (arg0))
1925 return operand_equal_p (TREE_OPERAND (arg0, 0),
1926 TREE_OPERAND (arg1, 0), 0);
1930 case ARRAY_RANGE_REF:
1931 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1932 TREE_OPERAND (arg1, 0), 0)
1933 && operand_equal_p (TREE_OPERAND (arg0, 1),
1934 TREE_OPERAND (arg1, 1), 0));
1937 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1938 TREE_OPERAND (arg1, 0), 0)
1939 && operand_equal_p (TREE_OPERAND (arg0, 1),
1940 TREE_OPERAND (arg1, 1), 0)
1941 && operand_equal_p (TREE_OPERAND (arg0, 2),
1942 TREE_OPERAND (arg1, 2), 0));
1948 if (TREE_CODE (arg0) == RTL_EXPR)
1949 return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
1957 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1958 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1960 When in doubt, return 0. */
1963 operand_equal_for_comparison_p (arg0, arg1, other)
1967 int unsignedp1, unsignedpo;
1968 tree primarg0, primarg1, primother;
1969 unsigned int correct_width;
1971 if (operand_equal_p (arg0, arg1, 0))
1974 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1975 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1978 /* Discard any conversions that don't change the modes of ARG0 and ARG1
1979 and see if the inner values are the same. This removes any
1980 signedness comparison, which doesn't matter here. */
1981 primarg0 = arg0, primarg1 = arg1;
1982 STRIP_NOPS (primarg0);
1983 STRIP_NOPS (primarg1);
1984 if (operand_equal_p (primarg0, primarg1, 0))
1987 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1988 actual comparison operand, ARG0.
1990 First throw away any conversions to wider types
1991 already present in the operands. */
1993 primarg1 = get_narrower (arg1, &unsignedp1);
1994 primother = get_narrower (other, &unsignedpo);
1996 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1997 if (unsignedp1 == unsignedpo
1998 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1999 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
2001 tree type = TREE_TYPE (arg0);
2003 /* Make sure shorter operand is extended the right way
2004 to match the longer operand. */
2005 primarg1 = convert ((*lang_hooks.types.signed_or_unsigned_type)
2006 (unsignedp1, TREE_TYPE (primarg1)), primarg1);
2008 if (operand_equal_p (arg0, convert (type, primarg1), 0))
2015 /* See if ARG is an expression that is either a comparison or is performing
2016 arithmetic on comparisons. The comparisons must only be comparing
2017 two different values, which will be stored in *CVAL1 and *CVAL2; if
2018 they are nonzero it means that some operands have already been found.
2019 No variables may be used anywhere else in the expression except in the
2020 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2021 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2023 If this is true, return 1. Otherwise, return zero. */
2026 twoval_comparison_p (arg, cval1, cval2, save_p)
2028 tree *cval1, *cval2;
2031 enum tree_code code = TREE_CODE (arg);
2032 char class = TREE_CODE_CLASS (code);
2034 /* We can handle some of the 'e' cases here. */
2035 if (class == 'e' && code == TRUTH_NOT_EXPR)
2037 else if (class == 'e'
2038 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
2039 || code == COMPOUND_EXPR))
2042 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0
2043 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
2045 /* If we've already found a CVAL1 or CVAL2, this expression is
2046 two complex to handle. */
2047 if (*cval1 || *cval2)
2057 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
2060 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
2061 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2062 cval1, cval2, save_p));
2068 if (code == COND_EXPR)
2069 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2070 cval1, cval2, save_p)
2071 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2072 cval1, cval2, save_p)
2073 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2074 cval1, cval2, save_p));
2078 /* First see if we can handle the first operand, then the second. For
2079 the second operand, we know *CVAL1 can't be zero. It must be that
2080 one side of the comparison is each of the values; test for the
2081 case where this isn't true by failing if the two operands
2084 if (operand_equal_p (TREE_OPERAND (arg, 0),
2085 TREE_OPERAND (arg, 1), 0))
2089 *cval1 = TREE_OPERAND (arg, 0);
2090 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2092 else if (*cval2 == 0)
2093 *cval2 = TREE_OPERAND (arg, 0);
2094 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2099 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2101 else if (*cval2 == 0)
2102 *cval2 = TREE_OPERAND (arg, 1);
2103 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2115 /* ARG is a tree that is known to contain just arithmetic operations and
2116 comparisons. Evaluate the operations in the tree substituting NEW0 for
2117 any occurrence of OLD0 as an operand of a comparison and likewise for
2121 eval_subst (arg, old0, new0, old1, new1)
2123 tree old0, new0, old1, new1;
2125 tree type = TREE_TYPE (arg);
2126 enum tree_code code = TREE_CODE (arg);
2127 char class = TREE_CODE_CLASS (code);
2129 /* We can handle some of the 'e' cases here. */
2130 if (class == 'e' && code == TRUTH_NOT_EXPR)
2132 else if (class == 'e'
2133 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2139 return fold (build1 (code, type,
2140 eval_subst (TREE_OPERAND (arg, 0),
2141 old0, new0, old1, new1)));
2144 return fold (build (code, type,
2145 eval_subst (TREE_OPERAND (arg, 0),
2146 old0, new0, old1, new1),
2147 eval_subst (TREE_OPERAND (arg, 1),
2148 old0, new0, old1, new1)));
2154 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2157 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2160 return fold (build (code, type,
2161 eval_subst (TREE_OPERAND (arg, 0),
2162 old0, new0, old1, new1),
2163 eval_subst (TREE_OPERAND (arg, 1),
2164 old0, new0, old1, new1),
2165 eval_subst (TREE_OPERAND (arg, 2),
2166 old0, new0, old1, new1)));
2170 /* fall through - ??? */
2174 tree arg0 = TREE_OPERAND (arg, 0);
2175 tree arg1 = TREE_OPERAND (arg, 1);
2177 /* We need to check both for exact equality and tree equality. The
2178 former will be true if the operand has a side-effect. In that
2179 case, we know the operand occurred exactly once. */
2181 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2183 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2186 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2188 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2191 return fold (build (code, type, arg0, arg1));
2199 /* Return a tree for the case when the result of an expression is RESULT
2200 converted to TYPE and OMITTED was previously an operand of the expression
2201 but is now not needed (e.g., we folded OMITTED * 0).
2203 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2204 the conversion of RESULT to TYPE. */
2207 omit_one_operand (type, result, omitted)
2208 tree type, result, omitted;
2210 tree t = convert (type, result);
2212 if (TREE_SIDE_EFFECTS (omitted))
2213 return build (COMPOUND_EXPR, type, omitted, t);
2215 return non_lvalue (t);
2218 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2221 pedantic_omit_one_operand (type, result, omitted)
2222 tree type, result, omitted;
2224 tree t = convert (type, result);
2226 if (TREE_SIDE_EFFECTS (omitted))
2227 return build (COMPOUND_EXPR, type, omitted, t);
2229 return pedantic_non_lvalue (t);
2232 /* Return a simplified tree node for the truth-negation of ARG. This
2233 never alters ARG itself. We assume that ARG is an operation that
2234 returns a truth value (0 or 1). */
2237 invert_truthvalue (arg)
2240 tree type = TREE_TYPE (arg);
2241 enum tree_code code = TREE_CODE (arg);
2243 if (code == ERROR_MARK)
2246 /* If this is a comparison, we can simply invert it, except for
2247 floating-point non-equality comparisons, in which case we just
2248 enclose a TRUTH_NOT_EXPR around what we have. */
2250 if (TREE_CODE_CLASS (code) == '<')
2252 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2253 && !flag_unsafe_math_optimizations
2256 return build1 (TRUTH_NOT_EXPR, type, arg);
2258 return build (invert_tree_comparison (code), type,
2259 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2265 return convert (type, build_int_2 (integer_zerop (arg), 0));
2267 case TRUTH_AND_EXPR:
2268 return build (TRUTH_OR_EXPR, type,
2269 invert_truthvalue (TREE_OPERAND (arg, 0)),
2270 invert_truthvalue (TREE_OPERAND (arg, 1)));
2273 return build (TRUTH_AND_EXPR, type,
2274 invert_truthvalue (TREE_OPERAND (arg, 0)),
2275 invert_truthvalue (TREE_OPERAND (arg, 1)));
2277 case TRUTH_XOR_EXPR:
2278 /* Here we can invert either operand. We invert the first operand
2279 unless the second operand is a TRUTH_NOT_EXPR in which case our
2280 result is the XOR of the first operand with the inside of the
2281 negation of the second operand. */
2283 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2284 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2285 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2287 return build (TRUTH_XOR_EXPR, type,
2288 invert_truthvalue (TREE_OPERAND (arg, 0)),
2289 TREE_OPERAND (arg, 1));
2291 case TRUTH_ANDIF_EXPR:
2292 return build (TRUTH_ORIF_EXPR, type,
2293 invert_truthvalue (TREE_OPERAND (arg, 0)),
2294 invert_truthvalue (TREE_OPERAND (arg, 1)));
2296 case TRUTH_ORIF_EXPR:
2297 return build (TRUTH_ANDIF_EXPR, type,
2298 invert_truthvalue (TREE_OPERAND (arg, 0)),
2299 invert_truthvalue (TREE_OPERAND (arg, 1)));
2301 case TRUTH_NOT_EXPR:
2302 return TREE_OPERAND (arg, 0);
2305 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2306 invert_truthvalue (TREE_OPERAND (arg, 1)),
2307 invert_truthvalue (TREE_OPERAND (arg, 2)));
2310 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2311 invert_truthvalue (TREE_OPERAND (arg, 1)));
2313 case WITH_RECORD_EXPR:
2314 return build (WITH_RECORD_EXPR, type,
2315 invert_truthvalue (TREE_OPERAND (arg, 0)),
2316 TREE_OPERAND (arg, 1));
2318 case NON_LVALUE_EXPR:
2319 return invert_truthvalue (TREE_OPERAND (arg, 0));
2324 return build1 (TREE_CODE (arg), type,
2325 invert_truthvalue (TREE_OPERAND (arg, 0)));
2328 if (!integer_onep (TREE_OPERAND (arg, 1)))
2330 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2333 return build1 (TRUTH_NOT_EXPR, type, arg);
2335 case CLEANUP_POINT_EXPR:
2336 return build1 (CLEANUP_POINT_EXPR, type,
2337 invert_truthvalue (TREE_OPERAND (arg, 0)));
2342 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2344 return build1 (TRUTH_NOT_EXPR, type, arg);
2347 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2348 operands are another bit-wise operation with a common input. If so,
2349 distribute the bit operations to save an operation and possibly two if
2350 constants are involved. For example, convert
2351 (A | B) & (A | C) into A | (B & C)
2352 Further simplification will occur if B and C are constants.
2354 If this optimization cannot be done, 0 will be returned. */
2357 distribute_bit_expr (code, type, arg0, arg1)
2358 enum tree_code code;
2365 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2366 || TREE_CODE (arg0) == code
2367 || (TREE_CODE (arg0) != BIT_AND_EXPR
2368 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2371 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2373 common = TREE_OPERAND (arg0, 0);
2374 left = TREE_OPERAND (arg0, 1);
2375 right = TREE_OPERAND (arg1, 1);
2377 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2379 common = TREE_OPERAND (arg0, 0);
2380 left = TREE_OPERAND (arg0, 1);
2381 right = TREE_OPERAND (arg1, 0);
2383 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2385 common = TREE_OPERAND (arg0, 1);
2386 left = TREE_OPERAND (arg0, 0);
2387 right = TREE_OPERAND (arg1, 1);
2389 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2391 common = TREE_OPERAND (arg0, 1);
2392 left = TREE_OPERAND (arg0, 0);
2393 right = TREE_OPERAND (arg1, 0);
2398 return fold (build (TREE_CODE (arg0), type, common,
2399 fold (build (code, type, left, right))));
2402 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2403 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
2406 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2409 int bitsize, bitpos;
2412 tree result = build (BIT_FIELD_REF, type, inner,
2413 size_int (bitsize), bitsize_int (bitpos));
2415 TREE_UNSIGNED (result) = unsignedp;
2420 /* Optimize a bit-field compare.
2422 There are two cases: First is a compare against a constant and the
2423 second is a comparison of two items where the fields are at the same
2424 bit position relative to the start of a chunk (byte, halfword, word)
2425 large enough to contain it. In these cases we can avoid the shift
2426 implicit in bitfield extractions.
2428 For constants, we emit a compare of the shifted constant with the
2429 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2430 compared. For two fields at the same position, we do the ANDs with the
2431 similar mask and compare the result of the ANDs.
2433 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2434 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2435 are the left and right operands of the comparison, respectively.
2437 If the optimization described above can be done, we return the resulting
2438 tree. Otherwise we return zero. */
2441 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2442 enum tree_code code;
2446 HOST_WIDE_INT lbitpos, lbitsize, rbitpos, rbitsize, nbitpos, nbitsize;
2447 tree type = TREE_TYPE (lhs);
2448 tree signed_type, unsigned_type;
2449 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2450 enum machine_mode lmode, rmode, nmode;
2451 int lunsignedp, runsignedp;
2452 int lvolatilep = 0, rvolatilep = 0;
2453 tree linner, rinner = NULL_TREE;
2457 /* Get all the information about the extractions being done. If the bit size
2458 if the same as the size of the underlying object, we aren't doing an
2459 extraction at all and so can do nothing. We also don't want to
2460 do anything if the inner expression is a PLACEHOLDER_EXPR since we
2461 then will no longer be able to replace it. */
2462 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2463 &lunsignedp, &lvolatilep);
2464 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2465 || offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR)
2470 /* If this is not a constant, we can only do something if bit positions,
2471 sizes, and signedness are the same. */
2472 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2473 &runsignedp, &rvolatilep);
2475 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2476 || lunsignedp != runsignedp || offset != 0
2477 || TREE_CODE (rinner) == PLACEHOLDER_EXPR)
2481 /* See if we can find a mode to refer to this field. We should be able to,
2482 but fail if we can't. */
2483 nmode = get_best_mode (lbitsize, lbitpos,
2484 const_p ? TYPE_ALIGN (TREE_TYPE (linner))
2485 : MIN (TYPE_ALIGN (TREE_TYPE (linner)),
2486 TYPE_ALIGN (TREE_TYPE (rinner))),
2487 word_mode, lvolatilep || rvolatilep);
2488 if (nmode == VOIDmode)
2491 /* Set signed and unsigned types of the precision of this mode for the
2493 signed_type = (*lang_hooks.types.type_for_mode) (nmode, 0);
2494 unsigned_type = (*lang_hooks.types.type_for_mode) (nmode, 1);
2496 /* Compute the bit position and size for the new reference and our offset
2497 within it. If the new reference is the same size as the original, we
2498 won't optimize anything, so return zero. */
2499 nbitsize = GET_MODE_BITSIZE (nmode);
2500 nbitpos = lbitpos & ~ (nbitsize - 1);
2502 if (nbitsize == lbitsize)
2505 if (BYTES_BIG_ENDIAN)
2506 lbitpos = nbitsize - lbitsize - lbitpos;
2508 /* Make the mask to be used against the extracted field. */
2509 mask = build_int_2 (~0, ~0);
2510 TREE_TYPE (mask) = unsigned_type;
2511 force_fit_type (mask, 0);
2512 mask = convert (unsigned_type, mask);
2513 mask = const_binop (LSHIFT_EXPR, mask, size_int (nbitsize - lbitsize), 0);
2514 mask = const_binop (RSHIFT_EXPR, mask,
2515 size_int (nbitsize - lbitsize - lbitpos), 0);
2518 /* If not comparing with constant, just rework the comparison
2520 return build (code, compare_type,
2521 build (BIT_AND_EXPR, unsigned_type,
2522 make_bit_field_ref (linner, unsigned_type,
2523 nbitsize, nbitpos, 1),
2525 build (BIT_AND_EXPR, unsigned_type,
2526 make_bit_field_ref (rinner, unsigned_type,
2527 nbitsize, nbitpos, 1),
2530 /* Otherwise, we are handling the constant case. See if the constant is too
2531 big for the field. Warn and return a tree of for 0 (false) if so. We do
2532 this not only for its own sake, but to avoid having to test for this
2533 error case below. If we didn't, we might generate wrong code.
2535 For unsigned fields, the constant shifted right by the field length should
2536 be all zero. For signed fields, the high-order bits should agree with
2541 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2542 convert (unsigned_type, rhs),
2543 size_int (lbitsize), 0)))
2545 warning ("comparison is always %d due to width of bit-field",
2547 return convert (compare_type,
2549 ? integer_one_node : integer_zero_node));
2554 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2555 size_int (lbitsize - 1), 0);
2556 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2558 warning ("comparison is always %d due to width of bit-field",
2560 return convert (compare_type,
2562 ? integer_one_node : integer_zero_node));
2566 /* Single-bit compares should always be against zero. */
2567 if (lbitsize == 1 && ! integer_zerop (rhs))
2569 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2570 rhs = convert (type, integer_zero_node);
2573 /* Make a new bitfield reference, shift the constant over the
2574 appropriate number of bits and mask it with the computed mask
2575 (in case this was a signed field). If we changed it, make a new one. */
2576 lhs = make_bit_field_ref (linner, unsigned_type, nbitsize, nbitpos, 1);
2579 TREE_SIDE_EFFECTS (lhs) = 1;
2580 TREE_THIS_VOLATILE (lhs) = 1;
2583 rhs = fold (const_binop (BIT_AND_EXPR,
2584 const_binop (LSHIFT_EXPR,
2585 convert (unsigned_type, rhs),
2586 size_int (lbitpos), 0),
2589 return build (code, compare_type,
2590 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2594 /* Subroutine for fold_truthop: decode a field reference.
2596 If EXP is a comparison reference, we return the innermost reference.
2598 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2599 set to the starting bit number.
2601 If the innermost field can be completely contained in a mode-sized
2602 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2604 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2605 otherwise it is not changed.
2607 *PUNSIGNEDP is set to the signedness of the field.
2609 *PMASK is set to the mask used. This is either contained in a
2610 BIT_AND_EXPR or derived from the width of the field.
2612 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
2614 Return 0 if this is not a component reference or is one that we can't
2615 do anything with. */
2618 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2619 pvolatilep, pmask, pand_mask)
2621 HOST_WIDE_INT *pbitsize, *pbitpos;
2622 enum machine_mode *pmode;
2623 int *punsignedp, *pvolatilep;
2628 tree mask, inner, offset;
2630 unsigned int precision;
2632 /* All the optimizations using this function assume integer fields.
2633 There are problems with FP fields since the type_for_size call
2634 below can fail for, e.g., XFmode. */
2635 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2640 if (TREE_CODE (exp) == BIT_AND_EXPR)
2642 and_mask = TREE_OPERAND (exp, 1);
2643 exp = TREE_OPERAND (exp, 0);
2644 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2645 if (TREE_CODE (and_mask) != INTEGER_CST)
2649 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2650 punsignedp, pvolatilep);
2651 if ((inner == exp && and_mask == 0)
2652 || *pbitsize < 0 || offset != 0
2653 || TREE_CODE (inner) == PLACEHOLDER_EXPR)
2656 /* Compute the mask to access the bitfield. */
2657 unsigned_type = (*lang_hooks.types.type_for_size) (*pbitsize, 1);
2658 precision = TYPE_PRECISION (unsigned_type);
2660 mask = build_int_2 (~0, ~0);
2661 TREE_TYPE (mask) = unsigned_type;
2662 force_fit_type (mask, 0);
2663 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2664 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2666 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2668 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2669 convert (unsigned_type, and_mask), mask));
2672 *pand_mask = and_mask;
2676 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
2680 all_ones_mask_p (mask, size)
2684 tree type = TREE_TYPE (mask);
2685 unsigned int precision = TYPE_PRECISION (type);
2688 tmask = build_int_2 (~0, ~0);
2689 TREE_TYPE (tmask) = (*lang_hooks.types.signed_type) (type);
2690 force_fit_type (tmask, 0);
2692 tree_int_cst_equal (mask,
2693 const_binop (RSHIFT_EXPR,
2694 const_binop (LSHIFT_EXPR, tmask,
2695 size_int (precision - size),
2697 size_int (precision - size), 0));
2700 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
2701 represents the sign bit of EXP's type. If EXP represents a sign
2702 or zero extension, also test VAL against the unextended type.
2703 The return value is the (sub)expression whose sign bit is VAL,
2704 or NULL_TREE otherwise. */
2707 sign_bit_p (exp, val)
2711 unsigned HOST_WIDE_INT lo;
2716 /* Tree EXP must have an integral type. */
2717 t = TREE_TYPE (exp);
2718 if (! INTEGRAL_TYPE_P (t))
2721 /* Tree VAL must be an integer constant. */
2722 if (TREE_CODE (val) != INTEGER_CST
2723 || TREE_CONSTANT_OVERFLOW (val))
2726 width = TYPE_PRECISION (t);
2727 if (width > HOST_BITS_PER_WIDE_INT)
2729 hi = (unsigned HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT - 1);
2735 lo = (unsigned HOST_WIDE_INT) 1 << (width - 1);
2738 if (TREE_INT_CST_HIGH (val) == hi && TREE_INT_CST_LOW (val) == lo)
2741 /* Handle extension from a narrower type. */
2742 if (TREE_CODE (exp) == NOP_EXPR
2743 && TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0))) < width)
2744 return sign_bit_p (TREE_OPERAND (exp, 0), val);
2749 /* Subroutine for fold_truthop: determine if an operand is simple enough
2750 to be evaluated unconditionally. */
2753 simple_operand_p (exp)
2756 /* Strip any conversions that don't change the machine mode. */
2757 while ((TREE_CODE (exp) == NOP_EXPR
2758 || TREE_CODE (exp) == CONVERT_EXPR)
2759 && (TYPE_MODE (TREE_TYPE (exp))
2760 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2761 exp = TREE_OPERAND (exp, 0);
2763 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2765 && ! TREE_ADDRESSABLE (exp)
2766 && ! TREE_THIS_VOLATILE (exp)
2767 && ! DECL_NONLOCAL (exp)
2768 /* Don't regard global variables as simple. They may be
2769 allocated in ways unknown to the compiler (shared memory,
2770 #pragma weak, etc). */
2771 && ! TREE_PUBLIC (exp)
2772 && ! DECL_EXTERNAL (exp)
2773 /* Loading a static variable is unduly expensive, but global
2774 registers aren't expensive. */
2775 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2778 /* The following functions are subroutines to fold_range_test and allow it to
2779 try to change a logical combination of comparisons into a range test.
2782 X == 2 || X == 3 || X == 4 || X == 5
2786 (unsigned) (X - 2) <= 3
2788 We describe each set of comparisons as being either inside or outside
2789 a range, using a variable named like IN_P, and then describe the
2790 range with a lower and upper bound. If one of the bounds is omitted,
2791 it represents either the highest or lowest value of the type.
2793 In the comments below, we represent a range by two numbers in brackets
2794 preceded by a "+" to designate being inside that range, or a "-" to
2795 designate being outside that range, so the condition can be inverted by
2796 flipping the prefix. An omitted bound is represented by a "-". For
2797 example, "- [-, 10]" means being outside the range starting at the lowest
2798 possible value and ending at 10, in other words, being greater than 10.
2799 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2802 We set up things so that the missing bounds are handled in a consistent
2803 manner so neither a missing bound nor "true" and "false" need to be
2804 handled using a special case. */
2806 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2807 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2808 and UPPER1_P are nonzero if the respective argument is an upper bound
2809 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2810 must be specified for a comparison. ARG1 will be converted to ARG0's
2811 type if both are specified. */
2814 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2815 enum tree_code code;
2818 int upper0_p, upper1_p;
2824 /* If neither arg represents infinity, do the normal operation.
2825 Else, if not a comparison, return infinity. Else handle the special
2826 comparison rules. Note that most of the cases below won't occur, but
2827 are handled for consistency. */
2829 if (arg0 != 0 && arg1 != 0)
2831 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2832 arg0, convert (TREE_TYPE (arg0), arg1)));
2834 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2837 if (TREE_CODE_CLASS (code) != '<')
2840 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2841 for neither. In real maths, we cannot assume open ended ranges are
2842 the same. But, this is computer arithmetic, where numbers are finite.
2843 We can therefore make the transformation of any unbounded range with
2844 the value Z, Z being greater than any representable number. This permits
2845 us to treat unbounded ranges as equal. */
2846 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2847 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2851 result = sgn0 == sgn1;
2854 result = sgn0 != sgn1;
2857 result = sgn0 < sgn1;
2860 result = sgn0 <= sgn1;
2863 result = sgn0 > sgn1;
2866 result = sgn0 >= sgn1;
2872 return convert (type, result ? integer_one_node : integer_zero_node);
2875 /* Given EXP, a logical expression, set the range it is testing into
2876 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2877 actually being tested. *PLOW and *PHIGH will be made of the same type
2878 as the returned expression. If EXP is not a comparison, we will most
2879 likely not be returning a useful value and range. */
2882 make_range (exp, pin_p, plow, phigh)
2887 enum tree_code code;
2888 tree arg0 = NULL_TREE, arg1 = NULL_TREE, type = NULL_TREE;
2889 tree orig_type = NULL_TREE;
2891 tree low, high, n_low, n_high;
2893 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2894 and see if we can refine the range. Some of the cases below may not
2895 happen, but it doesn't seem worth worrying about this. We "continue"
2896 the outer loop when we've changed something; otherwise we "break"
2897 the switch, which will "break" the while. */
2899 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2903 code = TREE_CODE (exp);
2905 if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
2907 arg0 = TREE_OPERAND (exp, 0);
2908 if (TREE_CODE_CLASS (code) == '<'
2909 || TREE_CODE_CLASS (code) == '1'
2910 || TREE_CODE_CLASS (code) == '2')
2911 type = TREE_TYPE (arg0);
2912 if (TREE_CODE_CLASS (code) == '2'
2913 || TREE_CODE_CLASS (code) == '<'
2914 || (TREE_CODE_CLASS (code) == 'e'
2915 && TREE_CODE_LENGTH (code) > 1))
2916 arg1 = TREE_OPERAND (exp, 1);
2919 /* Set ORIG_TYPE as soon as TYPE is non-null so that we do not
2920 lose a cast by accident. */
2921 if (type != NULL_TREE && orig_type == NULL_TREE)
2926 case TRUTH_NOT_EXPR:
2927 in_p = ! in_p, exp = arg0;
2930 case EQ_EXPR: case NE_EXPR:
2931 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2932 /* We can only do something if the range is testing for zero
2933 and if the second operand is an integer constant. Note that
2934 saying something is "in" the range we make is done by
2935 complementing IN_P since it will set in the initial case of
2936 being not equal to zero; "out" is leaving it alone. */
2937 if (low == 0 || high == 0
2938 || ! integer_zerop (low) || ! integer_zerop (high)
2939 || TREE_CODE (arg1) != INTEGER_CST)
2944 case NE_EXPR: /* - [c, c] */
2947 case EQ_EXPR: /* + [c, c] */
2948 in_p = ! in_p, low = high = arg1;
2950 case GT_EXPR: /* - [-, c] */
2951 low = 0, high = arg1;
2953 case GE_EXPR: /* + [c, -] */
2954 in_p = ! in_p, low = arg1, high = 0;
2956 case LT_EXPR: /* - [c, -] */
2957 low = arg1, high = 0;
2959 case LE_EXPR: /* + [-, c] */
2960 in_p = ! in_p, low = 0, high = arg1;
2968 /* If this is an unsigned comparison, we also know that EXP is
2969 greater than or equal to zero. We base the range tests we make
2970 on that fact, so we record it here so we can parse existing
2972 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2974 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2975 1, convert (type, integer_zero_node),
2979 in_p = n_in_p, low = n_low, high = n_high;
2981 /* If the high bound is missing, but we
2982 have a low bound, reverse the range so
2983 it goes from zero to the low bound minus 1. */
2984 if (high == 0 && low)
2987 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2988 integer_one_node, 0);
2989 low = convert (type, integer_zero_node);
2995 /* (-x) IN [a,b] -> x in [-b, -a] */
2996 n_low = range_binop (MINUS_EXPR, type,
2997 convert (type, integer_zero_node), 0, high, 1);
2998 n_high = range_binop (MINUS_EXPR, type,
2999 convert (type, integer_zero_node), 0, low, 0);
3000 low = n_low, high = n_high;
3006 exp = build (MINUS_EXPR, type, negate_expr (arg0),
3007 convert (type, integer_one_node));
3010 case PLUS_EXPR: case MINUS_EXPR:
3011 if (TREE_CODE (arg1) != INTEGER_CST)
3014 /* If EXP is signed, any overflow in the computation is undefined,
3015 so we don't worry about it so long as our computations on
3016 the bounds don't overflow. For unsigned, overflow is defined
3017 and this is exactly the right thing. */
3018 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3019 type, low, 0, arg1, 0);
3020 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
3021 type, high, 1, arg1, 0);
3022 if ((n_low != 0 && TREE_OVERFLOW (n_low))
3023 || (n_high != 0 && TREE_OVERFLOW (n_high)))
3026 /* Check for an unsigned range which has wrapped around the maximum
3027 value thus making n_high < n_low, and normalize it. */
3028 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
3030 low = range_binop (PLUS_EXPR, type, n_high, 0,
3031 integer_one_node, 0);
3032 high = range_binop (MINUS_EXPR, type, n_low, 0,
3033 integer_one_node, 0);
3035 /* If the range is of the form +/- [ x+1, x ], we won't
3036 be able to normalize it. But then, it represents the
3037 whole range or the empty set, so make it
3039 if (tree_int_cst_equal (n_low, low)
3040 && tree_int_cst_equal (n_high, high))
3046 low = n_low, high = n_high;
3051 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
3052 if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
3055 if (! INTEGRAL_TYPE_P (type)
3056 || (low != 0 && ! int_fits_type_p (low, type))
3057 || (high != 0 && ! int_fits_type_p (high, type)))
3060 n_low = low, n_high = high;
3063 n_low = convert (type, n_low);
3066 n_high = convert (type, n_high);
3068 /* If we're converting from an unsigned to a signed type,
3069 we will be doing the comparison as unsigned. The tests above
3070 have already verified that LOW and HIGH are both positive.
3072 So we have to make sure that the original unsigned value will
3073 be interpreted as positive. */
3074 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
3076 tree equiv_type = (*lang_hooks.types.type_for_mode)
3077 (TYPE_MODE (type), 1);
3080 /* A range without an upper bound is, naturally, unbounded.
3081 Since convert would have cropped a very large value, use
3082 the max value for the destination type. */
3084 = TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type)
3085 : TYPE_MAX_VALUE (type);
3087 if (TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (exp)))
3088 high_positive = fold (build (RSHIFT_EXPR, type,
3089 convert (type, high_positive),
3090 convert (type, integer_one_node)));
3092 /* If the low bound is specified, "and" the range with the
3093 range for which the original unsigned value will be
3097 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3099 1, convert (type, integer_zero_node),
3103 in_p = (n_in_p == in_p);
3107 /* Otherwise, "or" the range with the range of the input
3108 that will be interpreted as negative. */
3109 if (! merge_ranges (&n_in_p, &n_low, &n_high,
3111 1, convert (type, integer_zero_node),
3115 in_p = (in_p != n_in_p);
3120 low = n_low, high = n_high;
3130 /* If EXP is a constant, we can evaluate whether this is true or false. */
3131 if (TREE_CODE (exp) == INTEGER_CST)
3133 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
3135 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3141 *pin_p = in_p, *plow = low, *phigh = high;
3145 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3146 type, TYPE, return an expression to test if EXP is in (or out of, depending
3147 on IN_P) the range. */
3150 build_range_check (type, exp, in_p, low, high)
3156 tree etype = TREE_TYPE (exp);
3160 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3161 return invert_truthvalue (value);
3163 if (low == 0 && high == 0)
3164 return convert (type, integer_one_node);
3167 return fold (build (LE_EXPR, type, exp, high));
3170 return fold (build (GE_EXPR, type, exp, low));
3172 if (operand_equal_p (low, high, 0))
3173 return fold (build (EQ_EXPR, type, exp, low));
3175 if (integer_zerop (low))
3177 if (! TREE_UNSIGNED (etype))
3179 etype = (*lang_hooks.types.unsigned_type) (etype);
3180 high = convert (etype, high);
3181 exp = convert (etype, exp);
3183 return build_range_check (type, exp, 1, 0, high);
3186 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
3187 if (integer_onep (low) && TREE_CODE (high) == INTEGER_CST)
3189 unsigned HOST_WIDE_INT lo;
3193 prec = TYPE_PRECISION (etype);
3194 if (prec <= HOST_BITS_PER_WIDE_INT)
3197 lo = ((unsigned HOST_WIDE_INT) 1 << (prec - 1)) - 1;
3201 hi = ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)) - 1;
3202 lo = (unsigned HOST_WIDE_INT) -1;
3205 if (TREE_INT_CST_HIGH (high) == hi && TREE_INT_CST_LOW (high) == lo)
3207 if (TREE_UNSIGNED (etype))
3209 etype = (*lang_hooks.types.signed_type) (etype);
3210 exp = convert (etype, exp);
3212 return fold (build (GT_EXPR, type, exp,
3213 convert (etype, integer_zero_node)));
3217 if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3218 && ! TREE_OVERFLOW (value))
3219 return build_range_check (type,
3220 fold (build (MINUS_EXPR, etype, exp, low)),
3221 1, convert (etype, integer_zero_node), value);
3226 /* Given two ranges, see if we can merge them into one. Return 1 if we
3227 can, 0 if we can't. Set the output range into the specified parameters. */
3230 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3234 tree low0, high0, low1, high1;
3242 int lowequal = ((low0 == 0 && low1 == 0)
3243 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3244 low0, 0, low1, 0)));
3245 int highequal = ((high0 == 0 && high1 == 0)
3246 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3247 high0, 1, high1, 1)));
3249 /* Make range 0 be the range that starts first, or ends last if they
3250 start at the same value. Swap them if it isn't. */
3251 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3254 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3255 high1, 1, high0, 1))))
3257 temp = in0_p, in0_p = in1_p, in1_p = temp;
3258 tem = low0, low0 = low1, low1 = tem;
3259 tem = high0, high0 = high1, high1 = tem;
3262 /* Now flag two cases, whether the ranges are disjoint or whether the
3263 second range is totally subsumed in the first. Note that the tests
3264 below are simplified by the ones above. */
3265 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3266 high0, 1, low1, 0));
3267 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3268 high1, 1, high0, 1));
3270 /* We now have four cases, depending on whether we are including or
3271 excluding the two ranges. */
3274 /* If they don't overlap, the result is false. If the second range
3275 is a subset it is the result. Otherwise, the range is from the start
3276 of the second to the end of the first. */
3278 in_p = 0, low = high = 0;
3280 in_p = 1, low = low1, high = high1;
3282 in_p = 1, low = low1, high = high0;
3285 else if (in0_p && ! in1_p)
3287 /* If they don't overlap, the result is the first range. If they are
3288 equal, the result is false. If the second range is a subset of the
3289 first, and the ranges begin at the same place, we go from just after
3290 the end of the first range to the end of the second. If the second
3291 range is not a subset of the first, or if it is a subset and both
3292 ranges end at the same place, the range starts at the start of the
3293 first range and ends just before the second range.
3294 Otherwise, we can't describe this as a single range. */
3296 in_p = 1, low = low0, high = high0;
3297 else if (lowequal && highequal)
3298 in_p = 0, low = high = 0;
3299 else if (subset && lowequal)
3301 in_p = 1, high = high0;
3302 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3303 integer_one_node, 0);
3305 else if (! subset || highequal)
3307 in_p = 1, low = low0;
3308 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3309 integer_one_node, 0);
3315 else if (! in0_p && in1_p)
3317 /* If they don't overlap, the result is the second range. If the second
3318 is a subset of the first, the result is false. Otherwise,
3319 the range starts just after the first range and ends at the
3320 end of the second. */
3322 in_p = 1, low = low1, high = high1;
3323 else if (subset || highequal)
3324 in_p = 0, low = high = 0;
3327 in_p = 1, high = high1;
3328 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3329 integer_one_node, 0);
3335 /* The case where we are excluding both ranges. Here the complex case
3336 is if they don't overlap. In that case, the only time we have a
3337 range is if they are adjacent. If the second is a subset of the
3338 first, the result is the first. Otherwise, the range to exclude
3339 starts at the beginning of the first range and ends at the end of the
3343 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3344 range_binop (PLUS_EXPR, NULL_TREE,
3346 integer_one_node, 1),
3348 in_p = 0, low = low0, high = high1;
3353 in_p = 0, low = low0, high = high0;
3355 in_p = 0, low = low0, high = high1;
3358 *pin_p = in_p, *plow = low, *phigh = high;
3362 /* EXP is some logical combination of boolean tests. See if we can
3363 merge it into some range test. Return the new tree if so. */
3366 fold_range_test (exp)
3369 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3370 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3371 int in0_p, in1_p, in_p;
3372 tree low0, low1, low, high0, high1, high;
3373 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3374 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3377 /* If this is an OR operation, invert both sides; we will invert
3378 again at the end. */
3380 in0_p = ! in0_p, in1_p = ! in1_p;
3382 /* If both expressions are the same, if we can merge the ranges, and we
3383 can build the range test, return it or it inverted. If one of the
3384 ranges is always true or always false, consider it to be the same
3385 expression as the other. */
3386 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3387 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3389 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3391 : rhs != 0 ? rhs : integer_zero_node,
3393 return or_op ? invert_truthvalue (tem) : tem;
3395 /* On machines where the branch cost is expensive, if this is a
3396 short-circuited branch and the underlying object on both sides
3397 is the same, make a non-short-circuit operation. */
3398 else if (BRANCH_COST >= 2
3399 && lhs != 0 && rhs != 0
3400 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3401 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3402 && operand_equal_p (lhs, rhs, 0))
3404 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3405 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
3406 which cases we can't do this. */
3407 if (simple_operand_p (lhs))
3408 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3409 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3410 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3411 TREE_OPERAND (exp, 1));
3413 else if ((*lang_hooks.decls.global_bindings_p) () == 0
3414 && ! contains_placeholder_p (lhs))
3416 tree common = save_expr (lhs);
3418 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3419 or_op ? ! in0_p : in0_p,
3421 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3422 or_op ? ! in1_p : in1_p,
3424 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3425 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3426 TREE_TYPE (exp), lhs, rhs);
3433 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3434 bit value. Arrange things so the extra bits will be set to zero if and
3435 only if C is signed-extended to its full width. If MASK is nonzero,
3436 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3439 unextend (c, p, unsignedp, mask)
3445 tree type = TREE_TYPE (c);
3446 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3449 if (p == modesize || unsignedp)
3452 /* We work by getting just the sign bit into the low-order bit, then
3453 into the high-order bit, then sign-extend. We then XOR that value
3455 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3456 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3458 /* We must use a signed type in order to get an arithmetic right shift.
3459 However, we must also avoid introducing accidental overflows, so that
3460 a subsequent call to integer_zerop will work. Hence we must
3461 do the type conversion here. At this point, the constant is either
3462 zero or one, and the conversion to a signed type can never overflow.
3463 We could get an overflow if this conversion is done anywhere else. */
3464 if (TREE_UNSIGNED (type))
3465 temp = convert ((*lang_hooks.types.signed_type) (type), temp);
3467 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3468 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3470 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3471 /* If necessary, convert the type back to match the type of C. */
3472 if (TREE_UNSIGNED (type))
3473 temp = convert (type, temp);
3475 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3478 /* Find ways of folding logical expressions of LHS and RHS:
3479 Try to merge two comparisons to the same innermost item.
3480 Look for range tests like "ch >= '0' && ch <= '9'".
3481 Look for combinations of simple terms on machines with expensive branches
3482 and evaluate the RHS unconditionally.
3484 For example, if we have p->a == 2 && p->b == 4 and we can make an
3485 object large enough to span both A and B, we can do this with a comparison
3486 against the object ANDed with the a mask.
3488 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3489 operations to do this with one comparison.
3491 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3492 function and the one above.
3494 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3495 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3497 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3500 We return the simplified tree or 0 if no optimization is possible. */
3503 fold_truthop (code, truth_type, lhs, rhs)
3504 enum tree_code code;
3505 tree truth_type, lhs, rhs;
3507 /* If this is the "or" of two comparisons, we can do something if
3508 the comparisons are NE_EXPR. If this is the "and", we can do something
3509 if the comparisons are EQ_EXPR. I.e.,
3510 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3512 WANTED_CODE is this operation code. For single bit fields, we can
3513 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3514 comparison for one-bit fields. */
3516 enum tree_code wanted_code;
3517 enum tree_code lcode, rcode;
3518 tree ll_arg, lr_arg, rl_arg, rr_arg;
3519 tree ll_inner, lr_inner, rl_inner, rr_inner;
3520 HOST_WIDE_INT ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3521 HOST_WIDE_INT rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3522 HOST_WIDE_INT xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3523 HOST_WIDE_INT lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3524 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3525 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3526 enum machine_mode lnmode, rnmode;
3527 tree ll_mask, lr_mask, rl_mask, rr_mask;
3528 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3529 tree l_const, r_const;
3530 tree lntype, rntype, result;
3531 int first_bit, end_bit;
3534 /* Start by getting the comparison codes. Fail if anything is volatile.
3535 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3536 it were surrounded with a NE_EXPR. */
3538 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3541 lcode = TREE_CODE (lhs);
3542 rcode = TREE_CODE (rhs);
3544 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3545 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3547 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3548 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3550 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3553 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3554 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3556 ll_arg = TREE_OPERAND (lhs, 0);
3557 lr_arg = TREE_OPERAND (lhs, 1);
3558 rl_arg = TREE_OPERAND (rhs, 0);
3559 rr_arg = TREE_OPERAND (rhs, 1);
3561 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
3562 if (simple_operand_p (ll_arg)
3563 && simple_operand_p (lr_arg)
3564 && !FLOAT_TYPE_P (TREE_TYPE (ll_arg)))
3568 if (operand_equal_p (ll_arg, rl_arg, 0)
3569 && operand_equal_p (lr_arg, rr_arg, 0))
3571 int lcompcode, rcompcode;
3573 lcompcode = comparison_to_compcode (lcode);
3574 rcompcode = comparison_to_compcode (rcode);
3575 compcode = (code == TRUTH_AND_EXPR)
3576 ? lcompcode & rcompcode
3577 : lcompcode | rcompcode;
3579 else if (operand_equal_p (ll_arg, rr_arg, 0)
3580 && operand_equal_p (lr_arg, rl_arg, 0))
3582 int lcompcode, rcompcode;
3584 rcode = swap_tree_comparison (rcode);
3585 lcompcode = comparison_to_compcode (lcode);
3586 rcompcode = comparison_to_compcode (rcode);
3587 compcode = (code == TRUTH_AND_EXPR)
3588 ? lcompcode & rcompcode
3589 : lcompcode | rcompcode;
3594 if (compcode == COMPCODE_TRUE)
3595 return convert (truth_type, integer_one_node);
3596 else if (compcode == COMPCODE_FALSE)
3597 return convert (truth_type, integer_zero_node);
3598 else if (compcode != -1)
3599 return build (compcode_to_comparison (compcode),
3600 truth_type, ll_arg, lr_arg);
3603 /* If the RHS can be evaluated unconditionally and its operands are
3604 simple, it wins to evaluate the RHS unconditionally on machines
3605 with expensive branches. In this case, this isn't a comparison
3606 that can be merged. Avoid doing this if the RHS is a floating-point
3607 comparison since those can trap. */
3609 if (BRANCH_COST >= 2
3610 && ! FLOAT_TYPE_P (TREE_TYPE (rl_arg))
3611 && simple_operand_p (rl_arg)
3612 && simple_operand_p (rr_arg))
3614 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
3615 if (code == TRUTH_OR_EXPR
3616 && lcode == NE_EXPR && integer_zerop (lr_arg)
3617 && rcode == NE_EXPR && integer_zerop (rr_arg)
3618 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
3619 return build (NE_EXPR, truth_type,
3620 build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
3624 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
3625 if (code == TRUTH_AND_EXPR
3626 && lcode == EQ_EXPR && integer_zerop (lr_arg)
3627 && rcode == EQ_EXPR && integer_zerop (rr_arg)
3628 && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
3629 return build (EQ_EXPR, truth_type,
3630 build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
3634 return build (code, truth_type, lhs, rhs);
3637 /* See if the comparisons can be merged. Then get all the parameters for
3640 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3641 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3645 ll_inner = decode_field_reference (ll_arg,
3646 &ll_bitsize, &ll_bitpos, &ll_mode,
3647 &ll_unsignedp, &volatilep, &ll_mask,
3649 lr_inner = decode_field_reference (lr_arg,
3650 &lr_bitsize, &lr_bitpos, &lr_mode,
3651 &lr_unsignedp, &volatilep, &lr_mask,
3653 rl_inner = decode_field_reference (rl_arg,
3654 &rl_bitsize, &rl_bitpos, &rl_mode,
3655 &rl_unsignedp, &volatilep, &rl_mask,
3657 rr_inner = decode_field_reference (rr_arg,
3658 &rr_bitsize, &rr_bitpos, &rr_mode,
3659 &rr_unsignedp, &volatilep, &rr_mask,
3662 /* It must be true that the inner operation on the lhs of each
3663 comparison must be the same if we are to be able to do anything.
3664 Then see if we have constants. If not, the same must be true for
3666 if (volatilep || ll_inner == 0 || rl_inner == 0
3667 || ! operand_equal_p (ll_inner, rl_inner, 0))
3670 if (TREE_CODE (lr_arg) == INTEGER_CST
3671 && TREE_CODE (rr_arg) == INTEGER_CST)
3672 l_const = lr_arg, r_const = rr_arg;
3673 else if (lr_inner == 0 || rr_inner == 0
3674 || ! operand_equal_p (lr_inner, rr_inner, 0))
3677 l_const = r_const = 0;
3679 /* If either comparison code is not correct for our logical operation,
3680 fail. However, we can convert a one-bit comparison against zero into
3681 the opposite comparison against that bit being set in the field. */
3683 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3684 if (lcode != wanted_code)
3686 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3688 /* Make the left operand unsigned, since we are only interested
3689 in the value of one bit. Otherwise we are doing the wrong
3698 /* This is analogous to the code for l_const above. */
3699 if (rcode != wanted_code)
3701 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3710 /* After this point all optimizations will generate bit-field
3711 references, which we might not want. */
3712 if (! (*lang_hooks.can_use_bit_fields_p) ())
3715 /* See if we can find a mode that contains both fields being compared on
3716 the left. If we can't, fail. Otherwise, update all constants and masks
3717 to be relative to a field of that size. */
3718 first_bit = MIN (ll_bitpos, rl_bitpos);
3719 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3720 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3721 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3723 if (lnmode == VOIDmode)
3726 lnbitsize = GET_MODE_BITSIZE (lnmode);
3727 lnbitpos = first_bit & ~ (lnbitsize - 1);
3728 lntype = (*lang_hooks.types.type_for_size) (lnbitsize, 1);
3729 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3731 if (BYTES_BIG_ENDIAN)
3733 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3734 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3737 ll_mask = const_binop (LSHIFT_EXPR, convert (lntype, ll_mask),
3738 size_int (xll_bitpos), 0);
3739 rl_mask = const_binop (LSHIFT_EXPR, convert (lntype, rl_mask),
3740 size_int (xrl_bitpos), 0);
3744 l_const = convert (lntype, l_const);
3745 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3746 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3747 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3748 fold (build1 (BIT_NOT_EXPR,
3752 warning ("comparison is always %d", wanted_code == NE_EXPR);
3754 return convert (truth_type,
3755 wanted_code == NE_EXPR
3756 ? integer_one_node : integer_zero_node);
3761 r_const = convert (lntype, r_const);
3762 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3763 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3764 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3765 fold (build1 (BIT_NOT_EXPR,
3769 warning ("comparison is always %d", wanted_code == NE_EXPR);
3771 return convert (truth_type,
3772 wanted_code == NE_EXPR
3773 ? integer_one_node : integer_zero_node);
3777 /* If the right sides are not constant, do the same for it. Also,
3778 disallow this optimization if a size or signedness mismatch occurs
3779 between the left and right sides. */
3782 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3783 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3784 /* Make sure the two fields on the right
3785 correspond to the left without being swapped. */
3786 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3789 first_bit = MIN (lr_bitpos, rr_bitpos);
3790 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3791 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3792 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3794 if (rnmode == VOIDmode)
3797 rnbitsize = GET_MODE_BITSIZE (rnmode);
3798 rnbitpos = first_bit & ~ (rnbitsize - 1);
3799 rntype = (*lang_hooks.types.type_for_size) (rnbitsize, 1);
3800 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3802 if (BYTES_BIG_ENDIAN)
3804 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3805 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3808 lr_mask = const_binop (LSHIFT_EXPR, convert (rntype, lr_mask),
3809 size_int (xlr_bitpos), 0);
3810 rr_mask = const_binop (LSHIFT_EXPR, convert (rntype, rr_mask),
3811 size_int (xrr_bitpos), 0);
3813 /* Make a mask that corresponds to both fields being compared.
3814 Do this for both items being compared. If the operands are the
3815 same size and the bits being compared are in the same position
3816 then we can do this by masking both and comparing the masked
3818 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3819 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3820 if (lnbitsize == rnbitsize && xll_bitpos == xlr_bitpos)
3822 lhs = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
3823 ll_unsignedp || rl_unsignedp);
3824 if (! all_ones_mask_p (ll_mask, lnbitsize))
3825 lhs = build (BIT_AND_EXPR, lntype, lhs, ll_mask);
3827 rhs = make_bit_field_ref (lr_inner, rntype, rnbitsize, rnbitpos,
3828 lr_unsignedp || rr_unsignedp);
3829 if (! all_ones_mask_p (lr_mask, rnbitsize))
3830 rhs = build (BIT_AND_EXPR, rntype, rhs, lr_mask);
3832 return build (wanted_code, truth_type, lhs, rhs);
3835 /* There is still another way we can do something: If both pairs of
3836 fields being compared are adjacent, we may be able to make a wider
3837 field containing them both.
3839 Note that we still must mask the lhs/rhs expressions. Furthermore,
3840 the mask must be shifted to account for the shift done by
3841 make_bit_field_ref. */
3842 if ((ll_bitsize + ll_bitpos == rl_bitpos
3843 && lr_bitsize + lr_bitpos == rr_bitpos)
3844 || (ll_bitpos == rl_bitpos + rl_bitsize
3845 && lr_bitpos == rr_bitpos + rr_bitsize))
3849 lhs = make_bit_field_ref (ll_inner, lntype, ll_bitsize + rl_bitsize,
3850 MIN (ll_bitpos, rl_bitpos), ll_unsignedp);
3851 rhs = make_bit_field_ref (lr_inner, rntype, lr_bitsize + rr_bitsize,
3852 MIN (lr_bitpos, rr_bitpos), lr_unsignedp);
3854 ll_mask = const_binop (RSHIFT_EXPR, ll_mask,
3855 size_int (MIN (xll_bitpos, xrl_bitpos)), 0);
3856 lr_mask = const_binop (RSHIFT_EXPR, lr_mask,
3857 size_int (MIN (xlr_bitpos, xrr_bitpos)), 0);
3859 /* Convert to the smaller type before masking out unwanted bits. */
3861 if (lntype != rntype)
3863 if (lnbitsize > rnbitsize)
3865 lhs = convert (rntype, lhs);
3866 ll_mask = convert (rntype, ll_mask);
3869 else if (lnbitsize < rnbitsize)
3871 rhs = convert (lntype, rhs);
3872 lr_mask = convert (lntype, lr_mask);
3877 if (! all_ones_mask_p (ll_mask, ll_bitsize + rl_bitsize))
3878 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3880 if (! all_ones_mask_p (lr_mask, lr_bitsize + rr_bitsize))
3881 rhs = build (BIT_AND_EXPR, type, rhs, lr_mask);
3883 return build (wanted_code, truth_type, lhs, rhs);
3889 /* Handle the case of comparisons with constants. If there is something in
3890 common between the masks, those bits of the constants must be the same.
3891 If not, the condition is always false. Test for this to avoid generating
3892 incorrect code below. */
3893 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3894 if (! integer_zerop (result)
3895 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3896 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3898 if (wanted_code == NE_EXPR)
3900 warning ("`or' of unmatched not-equal tests is always 1");
3901 return convert (truth_type, integer_one_node);
3905 warning ("`and' of mutually exclusive equal-tests is always 0");
3906 return convert (truth_type, integer_zero_node);
3910 /* Construct the expression we will return. First get the component
3911 reference we will make. Unless the mask is all ones the width of
3912 that field, perform the mask operation. Then compare with the
3914 result = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
3915 ll_unsignedp || rl_unsignedp);
3917 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3918 if (! all_ones_mask_p (ll_mask, lnbitsize))
3919 result = build (BIT_AND_EXPR, lntype, result, ll_mask);
3921 return build (wanted_code, truth_type, result,
3922 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3925 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
3929 optimize_minmax_comparison (t)
3932 tree type = TREE_TYPE (t);
3933 tree arg0 = TREE_OPERAND (t, 0);
3934 enum tree_code op_code;
3935 tree comp_const = TREE_OPERAND (t, 1);
3937 int consts_equal, consts_lt;
3940 STRIP_SIGN_NOPS (arg0);
3942 op_code = TREE_CODE (arg0);
3943 minmax_const = TREE_OPERAND (arg0, 1);
3944 consts_equal = tree_int_cst_equal (minmax_const, comp_const);
3945 consts_lt = tree_int_cst_lt (minmax_const, comp_const);
3946 inner = TREE_OPERAND (arg0, 0);
3948 /* If something does not permit us to optimize, return the original tree. */
3949 if ((op_code != MIN_EXPR && op_code != MAX_EXPR)
3950 || TREE_CODE (comp_const) != INTEGER_CST
3951 || TREE_CONSTANT_OVERFLOW (comp_const)
3952 || TREE_CODE (minmax_const) != INTEGER_CST
3953 || TREE_CONSTANT_OVERFLOW (minmax_const))
3956 /* Now handle all the various comparison codes. We only handle EQ_EXPR
3957 and GT_EXPR, doing the rest with recursive calls using logical
3959 switch (TREE_CODE (t))
3961 case NE_EXPR: case LT_EXPR: case LE_EXPR:
3963 invert_truthvalue (optimize_minmax_comparison (invert_truthvalue (t)));
3967 fold (build (TRUTH_ORIF_EXPR, type,
3968 optimize_minmax_comparison
3969 (build (EQ_EXPR, type, arg0, comp_const)),
3970 optimize_minmax_comparison
3971 (build (GT_EXPR, type, arg0, comp_const))));
3974 if (op_code == MAX_EXPR && consts_equal)
3975 /* MAX (X, 0) == 0 -> X <= 0 */
3976 return fold (build (LE_EXPR, type, inner, comp_const));
3978 else if (op_code == MAX_EXPR && consts_lt)
3979 /* MAX (X, 0) == 5 -> X == 5 */
3980 return fold (build (EQ_EXPR, type, inner, comp_const));
3982 else if (op_code == MAX_EXPR)
3983 /* MAX (X, 0) == -1 -> false */
3984 return omit_one_operand (type, integer_zero_node, inner);
3986 else if (consts_equal)
3987 /* MIN (X, 0) == 0 -> X >= 0 */
3988 return fold (build (GE_EXPR, type, inner, comp_const));
3991 /* MIN (X, 0) == 5 -> false */
3992 return omit_one_operand (type, integer_zero_node, inner);
3995 /* MIN (X, 0) == -1 -> X == -1 */
3996 return fold (build (EQ_EXPR, type, inner, comp_const));
3999 if (op_code == MAX_EXPR && (consts_equal || consts_lt))
4000 /* MAX (X, 0) > 0 -> X > 0
4001 MAX (X, 0) > 5 -> X > 5 */
4002 return fold (build (GT_EXPR, type, inner, comp_const));
4004 else if (op_code == MAX_EXPR)
4005 /* MAX (X, 0) > -1 -> true */
4006 return omit_one_operand (type, integer_one_node, inner);
4008 else if (op_code == MIN_EXPR && (consts_equal || consts_lt))
4009 /* MIN (X, 0) > 0 -> false
4010 MIN (X, 0) > 5 -> false */
4011 return omit_one_operand (type, integer_zero_node, inner);
4014 /* MIN (X, 0) > -1 -> X > -1 */
4015 return fold (build (GT_EXPR, type, inner, comp_const));
4022 /* T is an integer expression that is being multiplied, divided, or taken a
4023 modulus (CODE says which and what kind of divide or modulus) by a
4024 constant C. See if we can eliminate that operation by folding it with
4025 other operations already in T. WIDE_TYPE, if non-null, is a type that
4026 should be used for the computation if wider than our type.
4028 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
4029 (X * 2) + (Y * 4). We must, however, be assured that either the original
4030 expression would not overflow or that overflow is undefined for the type
4031 in the language in question.
4033 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
4034 the machine has a multiply-accumulate insn or that this is part of an
4035 addressing calculation.
4037 If we return a non-null expression, it is an equivalent form of the
4038 original computation, but need not be in the original type. */
4041 extract_muldiv (t, c, code, wide_type)
4044 enum tree_code code;
4047 tree type = TREE_TYPE (t);
4048 enum tree_code tcode = TREE_CODE (t);
4049 tree ctype = (wide_type != 0 && (GET_MODE_SIZE (TYPE_MODE (wide_type))
4050 > GET_MODE_SIZE (TYPE_MODE (type)))
4051 ? wide_type : type);
4053 int same_p = tcode == code;
4054 tree op0 = NULL_TREE, op1 = NULL_TREE;
4056 /* Don't deal with constants of zero here; they confuse the code below. */
4057 if (integer_zerop (c))
4060 if (TREE_CODE_CLASS (tcode) == '1')
4061 op0 = TREE_OPERAND (t, 0);
4063 if (TREE_CODE_CLASS (tcode) == '2')
4064 op0 = TREE_OPERAND (t, 0), op1 = TREE_OPERAND (t, 1);
4066 /* Note that we need not handle conditional operations here since fold
4067 already handles those cases. So just do arithmetic here. */
4071 /* For a constant, we can always simplify if we are a multiply
4072 or (for divide and modulus) if it is a multiple of our constant. */
4073 if (code == MULT_EXPR
4074 || integer_zerop (const_binop (TRUNC_MOD_EXPR, t, c, 0)))
4075 return const_binop (code, convert (ctype, t), convert (ctype, c), 0);
4078 case CONVERT_EXPR: case NON_LVALUE_EXPR: case NOP_EXPR:
4079 /* If op0 is an expression ... */
4080 if ((TREE_CODE_CLASS (TREE_CODE (op0)) == '<'
4081 || TREE_CODE_CLASS (TREE_CODE (op0)) == '1'
4082 || TREE_CODE_CLASS (TREE_CODE (op0)) == '2'
4083 || TREE_CODE_CLASS (TREE_CODE (op0)) == 'e')
4084 /* ... and is unsigned, and its type is smaller than ctype,
4085 then we cannot pass through as widening. */
4086 && ((TREE_UNSIGNED (TREE_TYPE (op0))
4087 && ! (TREE_CODE (TREE_TYPE (op0)) == INTEGER_TYPE
4088 && TYPE_IS_SIZETYPE (TREE_TYPE (op0)))
4089 && (GET_MODE_SIZE (TYPE_MODE (ctype))
4090 > GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0)))))
4091 /* ... or its type is larger than ctype,
4092 then we cannot pass through this truncation. */
4093 || (GET_MODE_SIZE (TYPE_MODE (ctype))
4094 < GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))))
4097 /* Pass the constant down and see if we can make a simplification. If
4098 we can, replace this expression with the inner simplification for
4099 possible later conversion to our or some other type. */
4100 if (0 != (t1 = extract_muldiv (op0, convert (TREE_TYPE (op0), c), code,
4101 code == MULT_EXPR ? ctype : NULL_TREE)))
4105 case NEGATE_EXPR: case ABS_EXPR:
4106 if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
4107 return fold (build1 (tcode, ctype, convert (ctype, t1)));
4110 case MIN_EXPR: case MAX_EXPR:
4111 /* If widening the type changes the signedness, then we can't perform
4112 this optimization as that changes the result. */
4113 if (TREE_UNSIGNED (ctype) != TREE_UNSIGNED (type))
4116 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
4117 if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0
4118 && (t2 = extract_muldiv (op1, c, code, wide_type)) != 0)
4120 if (tree_int_cst_sgn (c) < 0)
4121 tcode = (tcode == MIN_EXPR ? MAX_EXPR : MIN_EXPR);
4123 return fold (build (tcode, ctype, convert (ctype, t1),
4124 convert (ctype, t2)));
4128 case WITH_RECORD_EXPR:
4129 if ((t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code, wide_type)) != 0)
4130 return build (WITH_RECORD_EXPR, TREE_TYPE (t1), t1,
4131 TREE_OPERAND (t, 1));
4135 /* If this has not been evaluated and the operand has no side effects,
4136 we can see if we can do something inside it and make a new one.
4137 Note that this test is overly conservative since we can do this
4138 if the only reason it had side effects is that it was another
4139 similar SAVE_EXPR, but that isn't worth bothering with. */
4140 if (SAVE_EXPR_RTL (t) == 0 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0))
4141 && 0 != (t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code,
4144 t1 = save_expr (t1);
4145 if (SAVE_EXPR_PERSISTENT_P (t) && TREE_CODE (t1) == SAVE_EXPR)
4146 SAVE_EXPR_PERSISTENT_P (t1) = 1;
4147 if (is_pending_size (t))
4148 put_pending_size (t1);
4153 case LSHIFT_EXPR: case RSHIFT_EXPR:
4154 /* If the second operand is constant, this is a multiplication
4155 or floor division, by a power of two, so we can treat it that
4156 way unless the multiplier or divisor overflows. */
4157 if (TREE_CODE (op1) == INTEGER_CST
4158 /* const_binop may not detect overflow correctly,
4159 so check for it explicitly here. */
4160 && TYPE_PRECISION (TREE_TYPE (size_one_node)) > TREE_INT_CST_LOW (op1)
4161 && TREE_INT_CST_HIGH (op1) == 0
4162 && 0 != (t1 = convert (ctype,
4163 const_binop (LSHIFT_EXPR, size_one_node,
4165 && ! TREE_OVERFLOW (t1))
4166 return extract_muldiv (build (tcode == LSHIFT_EXPR
4167 ? MULT_EXPR : FLOOR_DIV_EXPR,
4168 ctype, convert (ctype, op0), t1),
4169 c, code, wide_type);
4172 case PLUS_EXPR: case MINUS_EXPR:
4173 /* See if we can eliminate the operation on both sides. If we can, we
4174 can return a new PLUS or MINUS. If we can't, the only remaining
4175 cases where we can do anything are if the second operand is a
4177 t1 = extract_muldiv (op0, c, code, wide_type);
4178 t2 = extract_muldiv (op1, c, code, wide_type);
4179 if (t1 != 0 && t2 != 0
4180 && (code == MULT_EXPR
4181 /* If not multiplication, we can only do this if either operand
4182 is divisible by c. */
4183 || multiple_of_p (ctype, op0, c)
4184 || multiple_of_p (ctype, op1, c)))
4185 return fold (build (tcode, ctype, convert (ctype, t1),
4186 convert (ctype, t2)));
4188 /* If this was a subtraction, negate OP1 and set it to be an addition.
4189 This simplifies the logic below. */
4190 if (tcode == MINUS_EXPR)
4191 tcode = PLUS_EXPR, op1 = negate_expr (op1);
4193 if (TREE_CODE (op1) != INTEGER_CST)
4196 /* If either OP1 or C are negative, this optimization is not safe for
4197 some of the division and remainder types while for others we need
4198 to change the code. */
4199 if (tree_int_cst_sgn (op1) < 0 || tree_int_cst_sgn (c) < 0)
4201 if (code == CEIL_DIV_EXPR)
4202 code = FLOOR_DIV_EXPR;
4203 else if (code == FLOOR_DIV_EXPR)
4204 code = CEIL_DIV_EXPR;
4205 else if (code != MULT_EXPR
4206 && code != CEIL_MOD_EXPR && code != FLOOR_MOD_EXPR)
4210 /* If it's a multiply or a division/modulus operation of a multiple
4211 of our constant, do the operation and verify it doesn't overflow. */
4212 if (code == MULT_EXPR
4213 || integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4215 op1 = const_binop (code, convert (ctype, op1), convert (ctype, c), 0);
4216 if (op1 == 0 || TREE_OVERFLOW (op1))
4222 /* If we have an unsigned type is not a sizetype, we cannot widen
4223 the operation since it will change the result if the original
4224 computation overflowed. */
4225 if (TREE_UNSIGNED (ctype)
4226 && ! (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype))
4230 /* If we were able to eliminate our operation from the first side,
4231 apply our operation to the second side and reform the PLUS. */
4232 if (t1 != 0 && (TREE_CODE (t1) != code || code == MULT_EXPR))
4233 return fold (build (tcode, ctype, convert (ctype, t1), op1));
4235 /* The last case is if we are a multiply. In that case, we can
4236 apply the distributive law to commute the multiply and addition
4237 if the multiplication of the constants doesn't overflow. */
4238 if (code == MULT_EXPR)
4239 return fold (build (tcode, ctype, fold (build (code, ctype,
4240 convert (ctype, op0),
4241 convert (ctype, c))),
4247 /* We have a special case here if we are doing something like
4248 (C * 8) % 4 since we know that's zero. */
4249 if ((code == TRUNC_MOD_EXPR || code == CEIL_MOD_EXPR
4250 || code == FLOOR_MOD_EXPR || code == ROUND_MOD_EXPR)
4251 && TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST
4252 && integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4253 return omit_one_operand (type, integer_zero_node, op0);
4255 /* ... fall through ... */
4257 case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR:
4258 case ROUND_DIV_EXPR: case EXACT_DIV_EXPR:
4259 /* If we can extract our operation from the LHS, do so and return a
4260 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
4261 do something only if the second operand is a constant. */
4263 && (t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
4264 return fold (build (tcode, ctype, convert (ctype, t1),
4265 convert (ctype, op1)));
4266 else if (tcode == MULT_EXPR && code == MULT_EXPR
4267 && (t1 = extract_muldiv (op1, c, code, wide_type)) != 0)
4268 return fold (build (tcode, ctype, convert (ctype, op0),
4269 convert (ctype, t1)));
4270 else if (TREE_CODE (op1) != INTEGER_CST)
4273 /* If these are the same operation types, we can associate them
4274 assuming no overflow. */
4276 && 0 != (t1 = const_binop (MULT_EXPR, convert (ctype, op1),
4277 convert (ctype, c), 0))
4278 && ! TREE_OVERFLOW (t1))
4279 return fold (build (tcode, ctype, convert (ctype, op0), t1));
4281 /* If these operations "cancel" each other, we have the main
4282 optimizations of this pass, which occur when either constant is a
4283 multiple of the other, in which case we replace this with either an
4284 operation or CODE or TCODE.
4286 If we have an unsigned type that is not a sizetype, we cannot do
4287 this since it will change the result if the original computation
4289 if ((! TREE_UNSIGNED (ctype)
4290 || (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype)))
4291 && ((code == MULT_EXPR && tcode == EXACT_DIV_EXPR)
4292 || (tcode == MULT_EXPR
4293 && code != TRUNC_MOD_EXPR && code != CEIL_MOD_EXPR
4294 && code != FLOOR_MOD_EXPR && code != ROUND_MOD_EXPR)))
4296 if (integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
4297 return fold (build (tcode, ctype, convert (ctype, op0),
4299 const_binop (TRUNC_DIV_EXPR,
4301 else if (integer_zerop (const_binop (TRUNC_MOD_EXPR, c, op1, 0)))
4302 return fold (build (code, ctype, convert (ctype, op0),
4304 const_binop (TRUNC_DIV_EXPR,
4316 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
4317 S, a SAVE_EXPR, return the expression actually being evaluated. Note
4318 that we may sometimes modify the tree. */
4321 strip_compound_expr (t, s)
4325 enum tree_code code = TREE_CODE (t);
4327 /* See if this is the COMPOUND_EXPR we want to eliminate. */
4328 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
4329 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
4330 return TREE_OPERAND (t, 1);
4332 /* See if this is a COND_EXPR or a simple arithmetic operator. We
4333 don't bother handling any other types. */
4334 else if (code == COND_EXPR)
4336 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4337 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4338 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
4340 else if (TREE_CODE_CLASS (code) == '1')
4341 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4342 else if (TREE_CODE_CLASS (code) == '<'
4343 || TREE_CODE_CLASS (code) == '2')
4345 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
4346 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
4352 /* Return a node which has the indicated constant VALUE (either 0 or
4353 1), and is of the indicated TYPE. */
4356 constant_boolean_node (value, type)
4360 if (type == integer_type_node)
4361 return value ? integer_one_node : integer_zero_node;
4362 else if (TREE_CODE (type) == BOOLEAN_TYPE)
4363 return (*lang_hooks.truthvalue_conversion) (value ? integer_one_node :
4367 tree t = build_int_2 (value, 0);
4369 TREE_TYPE (t) = type;
4374 /* Utility function for the following routine, to see how complex a nesting of
4375 COND_EXPRs can be. EXPR is the expression and LIMIT is a count beyond which
4376 we don't care (to avoid spending too much time on complex expressions.). */
4379 count_cond (expr, lim)
4385 if (TREE_CODE (expr) != COND_EXPR)
4390 ctrue = count_cond (TREE_OPERAND (expr, 1), lim - 1);
4391 cfalse = count_cond (TREE_OPERAND (expr, 2), lim - 1 - ctrue);
4392 return MIN (lim, 1 + ctrue + cfalse);
4395 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
4396 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
4397 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
4398 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
4399 COND is the first argument to CODE; otherwise (as in the example
4400 given here), it is the second argument. TYPE is the type of the
4401 original expression. */
4404 fold_binary_op_with_conditional_arg (code, type, cond, arg, cond_first_p)
4405 enum tree_code code;
4411 tree test, true_value, false_value;
4412 tree lhs = NULL_TREE;
4413 tree rhs = NULL_TREE;
4414 /* In the end, we'll produce a COND_EXPR. Both arms of the
4415 conditional expression will be binary operations. The left-hand
4416 side of the expression to be executed if the condition is true
4417 will be pointed to by TRUE_LHS. Similarly, the right-hand side
4418 of the expression to be executed if the condition is true will be
4419 pointed to by TRUE_RHS. FALSE_LHS and FALSE_RHS are analogous --
4420 but apply to the expression to be executed if the conditional is
4426 /* These are the codes to use for the left-hand side and right-hand
4427 side of the COND_EXPR. Normally, they are the same as CODE. */
4428 enum tree_code lhs_code = code;
4429 enum tree_code rhs_code = code;
4430 /* And these are the types of the expressions. */
4431 tree lhs_type = type;
4432 tree rhs_type = type;
4437 true_rhs = false_rhs = &arg;
4438 true_lhs = &true_value;
4439 false_lhs = &false_value;
4443 true_lhs = false_lhs = &arg;
4444 true_rhs = &true_value;
4445 false_rhs = &false_value;
4448 if (TREE_CODE (cond) == COND_EXPR)
4450 test = TREE_OPERAND (cond, 0);
4451 true_value = TREE_OPERAND (cond, 1);
4452 false_value = TREE_OPERAND (cond, 2);
4453 /* If this operand throws an expression, then it does not make
4454 sense to try to perform a logical or arithmetic operation
4455 involving it. Instead of building `a + throw 3' for example,
4456 we simply build `a, throw 3'. */
4457 if (VOID_TYPE_P (TREE_TYPE (true_value)))
4461 lhs_code = COMPOUND_EXPR;
4462 lhs_type = void_type_node;
4467 if (VOID_TYPE_P (TREE_TYPE (false_value)))
4471 rhs_code = COMPOUND_EXPR;
4472 rhs_type = void_type_node;
4480 tree testtype = TREE_TYPE (cond);
4482 true_value = convert (testtype, integer_one_node);
4483 false_value = convert (testtype, integer_zero_node);
4486 /* If ARG is complex we want to make sure we only evaluate
4487 it once. Though this is only required if it is volatile, it
4488 might be more efficient even if it is not. However, if we
4489 succeed in folding one part to a constant, we do not need
4490 to make this SAVE_EXPR. Since we do this optimization
4491 primarily to see if we do end up with constant and this
4492 SAVE_EXPR interferes with later optimizations, suppressing
4493 it when we can is important.
4495 If we are not in a function, we can't make a SAVE_EXPR, so don't
4496 try to do so. Don't try to see if the result is a constant
4497 if an arm is a COND_EXPR since we get exponential behavior
4500 if (TREE_CODE (arg) == SAVE_EXPR)
4502 else if (lhs == 0 && rhs == 0
4503 && !TREE_CONSTANT (arg)
4504 && (*lang_hooks.decls.global_bindings_p) () == 0
4505 && ((TREE_CODE (arg) != VAR_DECL && TREE_CODE (arg) != PARM_DECL)
4506 || TREE_SIDE_EFFECTS (arg)))
4508 if (TREE_CODE (true_value) != COND_EXPR)
4509 lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
4511 if (TREE_CODE (false_value) != COND_EXPR)
4512 rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
4514 if ((lhs == 0 || ! TREE_CONSTANT (lhs))
4515 && (rhs == 0 || !TREE_CONSTANT (rhs)))
4517 arg = save_expr (arg);
4524 lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
4526 rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
4528 test = fold (build (COND_EXPR, type, test, lhs, rhs));
4531 return build (COMPOUND_EXPR, type,
4532 convert (void_type_node, arg),
4533 strip_compound_expr (test, arg));
4535 return convert (type, test);
4539 /* Subroutine of fold() that checks for the addition of +/- 0.0.
4541 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
4542 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
4543 ADDEND is the same as X.
4545 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
4546 and finite. The problematic cases are when X is zero, and its mode
4547 has signed zeros. In the case of rounding towards -infinity,
4548 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
4549 modes, X + 0 is not the same as X because -0 + 0 is 0. */
4552 fold_real_zero_addition_p (type, addend, negate)
4556 if (!real_zerop (addend))
4559 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
4560 if (!HONOR_SIGNED_ZEROS (TYPE_MODE (type)))
4563 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
4564 if (TREE_CODE (addend) == REAL_CST
4565 && REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (addend)))
4568 /* The mode has signed zeros, and we have to honor their sign.
4569 In this situation, there is only one case we can return true for.
4570 X - 0 is the same as X unless rounding towards -infinity is
4572 return negate && !HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (type));
4576 /* Perform constant folding and related simplification of EXPR.
4577 The related simplifications include x*1 => x, x*0 => 0, etc.,
4578 and application of the associative law.
4579 NOP_EXPR conversions may be removed freely (as long as we
4580 are careful not to change the C type of the overall expression)
4581 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
4582 but we can constant-fold them if they have constant operands. */
4589 tree t1 = NULL_TREE;
4591 tree type = TREE_TYPE (expr);
4592 tree arg0 = NULL_TREE, arg1 = NULL_TREE;
4593 enum tree_code code = TREE_CODE (t);
4594 int kind = TREE_CODE_CLASS (code);
4596 /* WINS will be nonzero when the switch is done
4597 if all operands are constant. */
4600 /* Don't try to process an RTL_EXPR since its operands aren't trees.
4601 Likewise for a SAVE_EXPR that's already been evaluated. */
4602 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t) != 0))
4605 /* Return right away if a constant. */
4609 #ifdef MAX_INTEGER_COMPUTATION_MODE
4610 check_max_integer_computation_mode (expr);
4613 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
4617 /* Special case for conversion ops that can have fixed point args. */
4618 arg0 = TREE_OPERAND (t, 0);
4620 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
4622 STRIP_SIGN_NOPS (arg0);
4624 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
4625 subop = TREE_REALPART (arg0);
4629 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
4630 && TREE_CODE (subop) != REAL_CST
4632 /* Note that TREE_CONSTANT isn't enough:
4633 static var addresses are constant but we can't
4634 do arithmetic on them. */
4637 else if (IS_EXPR_CODE_CLASS (kind) || kind == 'r')
4639 int len = first_rtl_op (code);
4641 for (i = 0; i < len; i++)
4643 tree op = TREE_OPERAND (t, i);
4647 continue; /* Valid for CALL_EXPR, at least. */
4649 if (kind == '<' || code == RSHIFT_EXPR)
4651 /* Signedness matters here. Perhaps we can refine this
4653 STRIP_SIGN_NOPS (op);
4656 /* Strip any conversions that don't change the mode. */
4659 if (TREE_CODE (op) == COMPLEX_CST)
4660 subop = TREE_REALPART (op);
4664 if (TREE_CODE (subop) != INTEGER_CST
4665 && TREE_CODE (subop) != REAL_CST)
4666 /* Note that TREE_CONSTANT isn't enough:
4667 static var addresses are constant but we can't
4668 do arithmetic on them. */
4678 /* If this is a commutative operation, and ARG0 is a constant, move it
4679 to ARG1 to reduce the number of tests below. */
4680 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
4681 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
4682 || code == BIT_AND_EXPR)
4683 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
4685 tem = arg0; arg0 = arg1; arg1 = tem;
4687 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
4688 TREE_OPERAND (t, 1) = tem;
4691 /* Now WINS is set as described above,
4692 ARG0 is the first operand of EXPR,
4693 and ARG1 is the second operand (if it has more than one operand).
4695 First check for cases where an arithmetic operation is applied to a
4696 compound, conditional, or comparison operation. Push the arithmetic
4697 operation inside the compound or conditional to see if any folding
4698 can then be done. Convert comparison to conditional for this purpose.
4699 The also optimizes non-constant cases that used to be done in
4702 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
4703 one of the operands is a comparison and the other is a comparison, a
4704 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
4705 code below would make the expression more complex. Change it to a
4706 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
4707 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
4709 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
4710 || code == EQ_EXPR || code == NE_EXPR)
4711 && ((truth_value_p (TREE_CODE (arg0))
4712 && (truth_value_p (TREE_CODE (arg1))
4713 || (TREE_CODE (arg1) == BIT_AND_EXPR
4714 && integer_onep (TREE_OPERAND (arg1, 1)))))
4715 || (truth_value_p (TREE_CODE (arg1))
4716 && (truth_value_p (TREE_CODE (arg0))
4717 || (TREE_CODE (arg0) == BIT_AND_EXPR
4718 && integer_onep (TREE_OPERAND (arg0, 1)))))))
4720 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
4721 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
4725 if (code == EQ_EXPR)
4726 t = invert_truthvalue (t);
4731 if (TREE_CODE_CLASS (code) == '1')
4733 if (TREE_CODE (arg0) == COMPOUND_EXPR)
4734 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4735 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
4736 else if (TREE_CODE (arg0) == COND_EXPR)
4738 tree arg01 = TREE_OPERAND (arg0, 1);
4739 tree arg02 = TREE_OPERAND (arg0, 2);
4740 if (! VOID_TYPE_P (TREE_TYPE (arg01)))
4741 arg01 = fold (build1 (code, type, arg01));
4742 if (! VOID_TYPE_P (TREE_TYPE (arg02)))
4743 arg02 = fold (build1 (code, type, arg02));
4744 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
4747 /* If this was a conversion, and all we did was to move into
4748 inside the COND_EXPR, bring it back out. But leave it if
4749 it is a conversion from integer to integer and the
4750 result precision is no wider than a word since such a
4751 conversion is cheap and may be optimized away by combine,
4752 while it couldn't if it were outside the COND_EXPR. Then return
4753 so we don't get into an infinite recursion loop taking the
4754 conversion out and then back in. */
4756 if ((code == NOP_EXPR || code == CONVERT_EXPR
4757 || code == NON_LVALUE_EXPR)
4758 && TREE_CODE (t) == COND_EXPR
4759 && TREE_CODE (TREE_OPERAND (t, 1)) == code
4760 && TREE_CODE (TREE_OPERAND (t, 2)) == code
4761 && ! VOID_TYPE_P (TREE_OPERAND (t, 1))
4762 && ! VOID_TYPE_P (TREE_OPERAND (t, 2))
4763 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
4764 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
4765 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
4767 (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))))
4768 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
4769 t = build1 (code, type,
4771 TREE_TYPE (TREE_OPERAND
4772 (TREE_OPERAND (t, 1), 0)),
4773 TREE_OPERAND (t, 0),
4774 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
4775 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
4778 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
4779 return fold (build (COND_EXPR, type, arg0,
4780 fold (build1 (code, type, integer_one_node)),
4781 fold (build1 (code, type, integer_zero_node))));
4783 else if (TREE_CODE_CLASS (code) == '2'
4784 || TREE_CODE_CLASS (code) == '<')
4786 if (TREE_CODE (arg1) == COMPOUND_EXPR)
4787 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4788 fold (build (code, type,
4789 arg0, TREE_OPERAND (arg1, 1))));
4790 else if ((TREE_CODE (arg1) == COND_EXPR
4791 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
4792 && TREE_CODE_CLASS (code) != '<'))
4793 && (TREE_CODE (arg0) != COND_EXPR
4794 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4795 && (! TREE_SIDE_EFFECTS (arg0)
4796 || ((*lang_hooks.decls.global_bindings_p) () == 0
4797 && ! contains_placeholder_p (arg0))))
4799 fold_binary_op_with_conditional_arg (code, type, arg1, arg0,
4800 /*cond_first_p=*/0);
4801 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
4802 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4803 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4804 else if ((TREE_CODE (arg0) == COND_EXPR
4805 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4806 && TREE_CODE_CLASS (code) != '<'))
4807 && (TREE_CODE (arg1) != COND_EXPR
4808 || count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
4809 && (! TREE_SIDE_EFFECTS (arg1)
4810 || ((*lang_hooks.decls.global_bindings_p) () == 0
4811 && ! contains_placeholder_p (arg1))))
4813 fold_binary_op_with_conditional_arg (code, type, arg0, arg1,
4814 /*cond_first_p=*/1);
4816 else if (TREE_CODE_CLASS (code) == '<'
4817 && TREE_CODE (arg0) == COMPOUND_EXPR)
4818 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4819 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4820 else if (TREE_CODE_CLASS (code) == '<'
4821 && TREE_CODE (arg1) == COMPOUND_EXPR)
4822 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4823 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4836 return fold (DECL_INITIAL (t));
4841 case FIX_TRUNC_EXPR:
4842 /* Other kinds of FIX are not handled properly by fold_convert. */
4844 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4845 return TREE_OPERAND (t, 0);
4847 /* Handle cases of two conversions in a row. */
4848 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4849 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4851 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4852 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4853 tree final_type = TREE_TYPE (t);
4854 int inside_int = INTEGRAL_TYPE_P (inside_type);
4855 int inside_ptr = POINTER_TYPE_P (inside_type);
4856 int inside_float = FLOAT_TYPE_P (inside_type);
4857 unsigned int inside_prec = TYPE_PRECISION (inside_type);
4858 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4859 int inter_int = INTEGRAL_TYPE_P (inter_type);
4860 int inter_ptr = POINTER_TYPE_P (inter_type);
4861 int inter_float = FLOAT_TYPE_P (inter_type);
4862 unsigned int inter_prec = TYPE_PRECISION (inter_type);
4863 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4864 int final_int = INTEGRAL_TYPE_P (final_type);
4865 int final_ptr = POINTER_TYPE_P (final_type);
4866 int final_float = FLOAT_TYPE_P (final_type);
4867 unsigned int final_prec = TYPE_PRECISION (final_type);
4868 int final_unsignedp = TREE_UNSIGNED (final_type);
4870 /* In addition to the cases of two conversions in a row
4871 handled below, if we are converting something to its own
4872 type via an object of identical or wider precision, neither
4873 conversion is needed. */
4874 if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (final_type)
4875 && ((inter_int && final_int) || (inter_float && final_float))
4876 && inter_prec >= final_prec)
4877 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4879 /* Likewise, if the intermediate and final types are either both
4880 float or both integer, we don't need the middle conversion if
4881 it is wider than the final type and doesn't change the signedness
4882 (for integers). Avoid this if the final type is a pointer
4883 since then we sometimes need the inner conversion. Likewise if
4884 the outer has a precision not equal to the size of its mode. */
4885 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4886 || (inter_float && inside_float))
4887 && inter_prec >= inside_prec
4888 && (inter_float || inter_unsignedp == inside_unsignedp)
4889 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4890 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4892 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4894 /* If we have a sign-extension of a zero-extended value, we can
4895 replace that by a single zero-extension. */
4896 if (inside_int && inter_int && final_int
4897 && inside_prec < inter_prec && inter_prec < final_prec
4898 && inside_unsignedp && !inter_unsignedp)
4899 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4901 /* Two conversions in a row are not needed unless:
4902 - some conversion is floating-point (overstrict for now), or
4903 - the intermediate type is narrower than both initial and
4905 - the intermediate type and innermost type differ in signedness,
4906 and the outermost type is wider than the intermediate, or
4907 - the initial type is a pointer type and the precisions of the
4908 intermediate and final types differ, or
4909 - the final type is a pointer type and the precisions of the
4910 initial and intermediate types differ. */
4911 if (! inside_float && ! inter_float && ! final_float
4912 && (inter_prec > inside_prec || inter_prec > final_prec)
4913 && ! (inside_int && inter_int
4914 && inter_unsignedp != inside_unsignedp
4915 && inter_prec < final_prec)
4916 && ((inter_unsignedp && inter_prec > inside_prec)
4917 == (final_unsignedp && final_prec > inter_prec))
4918 && ! (inside_ptr && inter_prec != final_prec)
4919 && ! (final_ptr && inside_prec != inter_prec)
4920 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4921 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4923 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4926 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4927 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4928 /* Detect assigning a bitfield. */
4929 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4930 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4932 /* Don't leave an assignment inside a conversion
4933 unless assigning a bitfield. */
4934 tree prev = TREE_OPERAND (t, 0);
4935 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4936 /* First do the assignment, then return converted constant. */
4937 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4942 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
4943 constants (if x has signed type, the sign bit cannot be set
4944 in c). This folds extension into the BIT_AND_EXPR. */
4945 if (INTEGRAL_TYPE_P (TREE_TYPE (t))
4946 && TREE_CODE (TREE_TYPE (t)) != BOOLEAN_TYPE
4947 && TREE_CODE (TREE_OPERAND (t, 0)) == BIT_AND_EXPR
4948 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 1)) == INTEGER_CST)
4950 tree and = TREE_OPERAND (t, 0);
4951 tree and0 = TREE_OPERAND (and, 0), and1 = TREE_OPERAND (and, 1);
4954 if (TREE_UNSIGNED (TREE_TYPE (and))
4955 || (TYPE_PRECISION (TREE_TYPE (t))
4956 <= TYPE_PRECISION (TREE_TYPE (and))))
4958 else if (TYPE_PRECISION (TREE_TYPE (and1))
4959 <= HOST_BITS_PER_WIDE_INT
4960 && host_integerp (and1, 1))
4962 unsigned HOST_WIDE_INT cst;
4964 cst = tree_low_cst (and1, 1);
4965 cst &= (HOST_WIDE_INT) -1
4966 << (TYPE_PRECISION (TREE_TYPE (and1)) - 1);
4967 change = (cst == 0);
4968 #ifdef LOAD_EXTEND_OP
4970 && (LOAD_EXTEND_OP (TYPE_MODE (TREE_TYPE (and0)))
4973 tree uns = (*lang_hooks.types.unsigned_type) (TREE_TYPE (and0));
4974 and0 = convert (uns, and0);
4975 and1 = convert (uns, and1);
4980 return fold (build (BIT_AND_EXPR, TREE_TYPE (t),
4981 convert (TREE_TYPE (t), and0),
4982 convert (TREE_TYPE (t), and1)));
4987 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4990 return fold_convert (t, arg0);
4992 case VIEW_CONVERT_EXPR:
4993 if (TREE_CODE (TREE_OPERAND (t, 0)) == VIEW_CONVERT_EXPR)
4994 return build1 (VIEW_CONVERT_EXPR, type,
4995 TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4999 if (TREE_CODE (arg0) == CONSTRUCTOR)
5001 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
5008 TREE_CONSTANT (t) = wins;
5014 if (TREE_CODE (arg0) == INTEGER_CST)
5016 unsigned HOST_WIDE_INT low;
5018 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
5019 TREE_INT_CST_HIGH (arg0),
5021 t = build_int_2 (low, high);
5022 TREE_TYPE (t) = type;
5024 = (TREE_OVERFLOW (arg0)
5025 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
5026 TREE_CONSTANT_OVERFLOW (t)
5027 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
5029 else if (TREE_CODE (arg0) == REAL_CST)
5030 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
5032 else if (TREE_CODE (arg0) == NEGATE_EXPR)
5033 return TREE_OPERAND (arg0, 0);
5035 /* Convert - (a - b) to (b - a) for non-floating-point. */
5036 else if (TREE_CODE (arg0) == MINUS_EXPR
5037 && (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
5038 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
5039 TREE_OPERAND (arg0, 0));
5046 if (TREE_CODE (arg0) == INTEGER_CST)
5048 /* If the value is unsigned, then the absolute value is
5049 the same as the ordinary value. */
5050 if (TREE_UNSIGNED (type))
5052 /* Similarly, if the value is non-negative. */
5053 else if (INT_CST_LT (integer_minus_one_node, arg0))
5055 /* If the value is negative, then the absolute value is
5059 unsigned HOST_WIDE_INT low;
5061 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
5062 TREE_INT_CST_HIGH (arg0),
5064 t = build_int_2 (low, high);
5065 TREE_TYPE (t) = type;
5067 = (TREE_OVERFLOW (arg0)
5068 | force_fit_type (t, overflow));
5069 TREE_CONSTANT_OVERFLOW (t)
5070 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
5073 else if (TREE_CODE (arg0) == REAL_CST)
5075 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
5076 t = build_real (type,
5077 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
5080 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
5081 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
5085 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5086 return convert (type, arg0);
5087 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5088 return build (COMPLEX_EXPR, type,
5089 TREE_OPERAND (arg0, 0),
5090 negate_expr (TREE_OPERAND (arg0, 1)));
5091 else if (TREE_CODE (arg0) == COMPLEX_CST)
5092 return build_complex (type, TREE_REALPART (arg0),
5093 negate_expr (TREE_IMAGPART (arg0)));
5094 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5095 return fold (build (TREE_CODE (arg0), type,
5096 fold (build1 (CONJ_EXPR, type,
5097 TREE_OPERAND (arg0, 0))),
5098 fold (build1 (CONJ_EXPR,
5099 type, TREE_OPERAND (arg0, 1)))));
5100 else if (TREE_CODE (arg0) == CONJ_EXPR)
5101 return TREE_OPERAND (arg0, 0);
5107 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
5108 ~ TREE_INT_CST_HIGH (arg0));
5109 TREE_TYPE (t) = type;
5110 force_fit_type (t, 0);
5111 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
5112 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
5114 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
5115 return TREE_OPERAND (arg0, 0);
5119 /* A + (-B) -> A - B */
5120 if (TREE_CODE (arg1) == NEGATE_EXPR)
5121 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
5122 /* (-A) + B -> B - A */
5123 if (TREE_CODE (arg0) == NEGATE_EXPR)
5124 return fold (build (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
5125 else if (! FLOAT_TYPE_P (type))
5127 if (integer_zerop (arg1))
5128 return non_lvalue (convert (type, arg0));
5130 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
5131 with a constant, and the two constants have no bits in common,
5132 we should treat this as a BIT_IOR_EXPR since this may produce more
5134 if (TREE_CODE (arg0) == BIT_AND_EXPR
5135 && TREE_CODE (arg1) == BIT_AND_EXPR
5136 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5137 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
5138 && integer_zerop (const_binop (BIT_AND_EXPR,
5139 TREE_OPERAND (arg0, 1),
5140 TREE_OPERAND (arg1, 1), 0)))
5142 code = BIT_IOR_EXPR;
5146 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
5147 (plus (plus (mult) (mult)) (foo)) so that we can
5148 take advantage of the factoring cases below. */
5149 if ((TREE_CODE (arg0) == PLUS_EXPR
5150 && TREE_CODE (arg1) == MULT_EXPR)
5151 || (TREE_CODE (arg1) == PLUS_EXPR
5152 && TREE_CODE (arg0) == MULT_EXPR))
5154 tree parg0, parg1, parg, marg;
5156 if (TREE_CODE (arg0) == PLUS_EXPR)
5157 parg = arg0, marg = arg1;
5159 parg = arg1, marg = arg0;
5160 parg0 = TREE_OPERAND (parg, 0);
5161 parg1 = TREE_OPERAND (parg, 1);
5165 if (TREE_CODE (parg0) == MULT_EXPR
5166 && TREE_CODE (parg1) != MULT_EXPR)
5167 return fold (build (PLUS_EXPR, type,
5168 fold (build (PLUS_EXPR, type, parg0, marg)),
5170 if (TREE_CODE (parg0) != MULT_EXPR
5171 && TREE_CODE (parg1) == MULT_EXPR)
5172 return fold (build (PLUS_EXPR, type,
5173 fold (build (PLUS_EXPR, type, parg1, marg)),
5177 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
5179 tree arg00, arg01, arg10, arg11;
5180 tree alt0 = NULL_TREE, alt1 = NULL_TREE, same;
5182 /* (A * C) + (B * C) -> (A+B) * C.
5183 We are most concerned about the case where C is a constant,
5184 but other combinations show up during loop reduction. Since
5185 it is not difficult, try all four possibilities. */
5187 arg00 = TREE_OPERAND (arg0, 0);
5188 arg01 = TREE_OPERAND (arg0, 1);
5189 arg10 = TREE_OPERAND (arg1, 0);
5190 arg11 = TREE_OPERAND (arg1, 1);
5193 if (operand_equal_p (arg01, arg11, 0))
5194 same = arg01, alt0 = arg00, alt1 = arg10;
5195 else if (operand_equal_p (arg00, arg10, 0))
5196 same = arg00, alt0 = arg01, alt1 = arg11;
5197 else if (operand_equal_p (arg00, arg11, 0))
5198 same = arg00, alt0 = arg01, alt1 = arg10;
5199 else if (operand_equal_p (arg01, arg10, 0))
5200 same = arg01, alt0 = arg00, alt1 = arg11;
5202 /* No identical multiplicands; see if we can find a common
5203 power-of-two factor in non-power-of-two multiplies. This
5204 can help in multi-dimensional array access. */
5205 else if (TREE_CODE (arg01) == INTEGER_CST
5206 && TREE_CODE (arg11) == INTEGER_CST
5207 && TREE_INT_CST_HIGH (arg01) == 0
5208 && TREE_INT_CST_HIGH (arg11) == 0)
5210 HOST_WIDE_INT int01, int11, tmp;
5211 int01 = TREE_INT_CST_LOW (arg01);
5212 int11 = TREE_INT_CST_LOW (arg11);
5214 /* Move min of absolute values to int11. */
5215 if ((int01 >= 0 ? int01 : -int01)
5216 < (int11 >= 0 ? int11 : -int11))
5218 tmp = int01, int01 = int11, int11 = tmp;
5219 alt0 = arg00, arg00 = arg10, arg10 = alt0;
5220 alt0 = arg01, arg01 = arg11, arg11 = alt0;
5223 if (exact_log2 (int11) > 0 && int01 % int11 == 0)
5225 alt0 = fold (build (MULT_EXPR, type, arg00,
5226 build_int_2 (int01 / int11, 0)));
5233 return fold (build (MULT_EXPR, type,
5234 fold (build (PLUS_EXPR, type, alt0, alt1)),
5239 /* See if ARG1 is zero and X + ARG1 reduces to X. */
5240 else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0))
5241 return non_lvalue (convert (type, arg0));
5243 /* Likewise if the operands are reversed. */
5244 else if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
5245 return non_lvalue (convert (type, arg1));
5248 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
5249 is a rotate of A by C1 bits. */
5250 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
5251 is a rotate of A by B bits. */
5253 enum tree_code code0, code1;
5254 code0 = TREE_CODE (arg0);
5255 code1 = TREE_CODE (arg1);
5256 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
5257 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
5258 && operand_equal_p (TREE_OPERAND (arg0, 0),
5259 TREE_OPERAND (arg1, 0), 0)
5260 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5262 tree tree01, tree11;
5263 enum tree_code code01, code11;
5265 tree01 = TREE_OPERAND (arg0, 1);
5266 tree11 = TREE_OPERAND (arg1, 1);
5267 STRIP_NOPS (tree01);
5268 STRIP_NOPS (tree11);
5269 code01 = TREE_CODE (tree01);
5270 code11 = TREE_CODE (tree11);
5271 if (code01 == INTEGER_CST
5272 && code11 == INTEGER_CST
5273 && TREE_INT_CST_HIGH (tree01) == 0
5274 && TREE_INT_CST_HIGH (tree11) == 0
5275 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
5276 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
5277 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
5278 code0 == LSHIFT_EXPR ? tree01 : tree11);
5279 else if (code11 == MINUS_EXPR)
5281 tree tree110, tree111;
5282 tree110 = TREE_OPERAND (tree11, 0);
5283 tree111 = TREE_OPERAND (tree11, 1);
5284 STRIP_NOPS (tree110);
5285 STRIP_NOPS (tree111);
5286 if (TREE_CODE (tree110) == INTEGER_CST
5287 && 0 == compare_tree_int (tree110,
5289 (TREE_TYPE (TREE_OPERAND
5291 && operand_equal_p (tree01, tree111, 0))
5292 return build ((code0 == LSHIFT_EXPR
5295 type, TREE_OPERAND (arg0, 0), tree01);
5297 else if (code01 == MINUS_EXPR)
5299 tree tree010, tree011;
5300 tree010 = TREE_OPERAND (tree01, 0);
5301 tree011 = TREE_OPERAND (tree01, 1);
5302 STRIP_NOPS (tree010);
5303 STRIP_NOPS (tree011);
5304 if (TREE_CODE (tree010) == INTEGER_CST
5305 && 0 == compare_tree_int (tree010,
5307 (TREE_TYPE (TREE_OPERAND
5309 && operand_equal_p (tree11, tree011, 0))
5310 return build ((code0 != LSHIFT_EXPR
5313 type, TREE_OPERAND (arg0, 0), tree11);
5319 /* In most languages, can't associate operations on floats through
5320 parentheses. Rather than remember where the parentheses were, we
5321 don't associate floats at all. It shouldn't matter much. However,
5322 associating multiplications is only very slightly inaccurate, so do
5323 that if -funsafe-math-optimizations is specified. */
5326 && (! FLOAT_TYPE_P (type)
5327 || (flag_unsafe_math_optimizations && code == MULT_EXPR)))
5329 tree var0, con0, lit0, minus_lit0;
5330 tree var1, con1, lit1, minus_lit1;
5332 /* Split both trees into variables, constants, and literals. Then
5333 associate each group together, the constants with literals,
5334 then the result with variables. This increases the chances of
5335 literals being recombined later and of generating relocatable
5336 expressions for the sum of a constant and literal. */
5337 var0 = split_tree (arg0, code, &con0, &lit0, &minus_lit0, 0);
5338 var1 = split_tree (arg1, code, &con1, &lit1, &minus_lit1,
5339 code == MINUS_EXPR);
5341 /* Only do something if we found more than two objects. Otherwise,
5342 nothing has changed and we risk infinite recursion. */
5343 if (2 < ((var0 != 0) + (var1 != 0)
5344 + (con0 != 0) + (con1 != 0)
5345 + (lit0 != 0) + (lit1 != 0)
5346 + (minus_lit0 != 0) + (minus_lit1 != 0)))
5348 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
5349 if (code == MINUS_EXPR)
5352 var0 = associate_trees (var0, var1, code, type);
5353 con0 = associate_trees (con0, con1, code, type);
5354 lit0 = associate_trees (lit0, lit1, code, type);
5355 minus_lit0 = associate_trees (minus_lit0, minus_lit1, code, type);
5357 /* Preserve the MINUS_EXPR if the negative part of the literal is
5358 greater than the positive part. Otherwise, the multiplicative
5359 folding code (i.e extract_muldiv) may be fooled in case
5360 unsigned constants are substracted, like in the following
5361 example: ((X*2 + 4) - 8U)/2. */
5362 if (minus_lit0 && lit0)
5364 if (tree_int_cst_lt (lit0, minus_lit0))
5366 minus_lit0 = associate_trees (minus_lit0, lit0,
5372 lit0 = associate_trees (lit0, minus_lit0,
5380 return convert (type, associate_trees (var0, minus_lit0,
5384 con0 = associate_trees (con0, minus_lit0,
5386 return convert (type, associate_trees (var0, con0,
5391 con0 = associate_trees (con0, lit0, code, type);
5392 return convert (type, associate_trees (var0, con0, code, type));
5398 t1 = const_binop (code, arg0, arg1, 0);
5399 if (t1 != NULL_TREE)
5401 /* The return value should always have
5402 the same type as the original expression. */
5403 if (TREE_TYPE (t1) != TREE_TYPE (t))
5404 t1 = convert (TREE_TYPE (t), t1);
5411 /* A - (-B) -> A + B */
5412 if (TREE_CODE (arg1) == NEGATE_EXPR)
5413 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
5414 /* (-A) - CST -> (-CST) - A for floating point (what about ints ?) */
5415 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
5417 fold (build (MINUS_EXPR, type,
5418 build_real (TREE_TYPE (arg1),
5419 REAL_VALUE_NEGATE (TREE_REAL_CST (arg1))),
5420 TREE_OPERAND (arg0, 0)));
5422 if (! FLOAT_TYPE_P (type))
5424 if (! wins && integer_zerop (arg0))
5425 return negate_expr (convert (type, arg1));
5426 if (integer_zerop (arg1))
5427 return non_lvalue (convert (type, arg0));
5429 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
5430 about the case where C is a constant, just try one of the
5431 four possibilities. */
5433 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
5434 && operand_equal_p (TREE_OPERAND (arg0, 1),
5435 TREE_OPERAND (arg1, 1), 0))
5436 return fold (build (MULT_EXPR, type,
5437 fold (build (MINUS_EXPR, type,
5438 TREE_OPERAND (arg0, 0),
5439 TREE_OPERAND (arg1, 0))),
5440 TREE_OPERAND (arg0, 1)));
5443 /* See if ARG1 is zero and X - ARG1 reduces to X. */
5444 else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 1))
5445 return non_lvalue (convert (type, arg0));
5447 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
5448 ARG0 is zero and X + ARG0 reduces to X, since that would mean
5449 (-ARG1 + ARG0) reduces to -ARG1. */
5450 else if (!wins && fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
5451 return negate_expr (convert (type, arg1));
5453 /* Fold &x - &x. This can happen from &x.foo - &x.
5454 This is unsafe for certain floats even in non-IEEE formats.
5455 In IEEE, it is unsafe because it does wrong for NaNs.
5456 Also note that operand_equal_p is always false if an operand
5459 if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
5460 && operand_equal_p (arg0, arg1, 0))
5461 return convert (type, integer_zero_node);
5466 /* (-A) * (-B) -> A * B */
5467 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
5468 return fold (build (MULT_EXPR, type, TREE_OPERAND (arg0, 0),
5469 TREE_OPERAND (arg1, 0)));
5471 if (! FLOAT_TYPE_P (type))
5473 if (integer_zerop (arg1))
5474 return omit_one_operand (type, arg1, arg0);
5475 if (integer_onep (arg1))
5476 return non_lvalue (convert (type, arg0));
5478 /* (a * (1 << b)) is (a << b) */
5479 if (TREE_CODE (arg1) == LSHIFT_EXPR
5480 && integer_onep (TREE_OPERAND (arg1, 0)))
5481 return fold (build (LSHIFT_EXPR, type, arg0,
5482 TREE_OPERAND (arg1, 1)));
5483 if (TREE_CODE (arg0) == LSHIFT_EXPR
5484 && integer_onep (TREE_OPERAND (arg0, 0)))
5485 return fold (build (LSHIFT_EXPR, type, arg1,
5486 TREE_OPERAND (arg0, 1)));
5488 if (TREE_CODE (arg1) == INTEGER_CST
5489 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5491 return convert (type, tem);
5496 /* Maybe fold x * 0 to 0. The expressions aren't the same
5497 when x is NaN, since x * 0 is also NaN. Nor are they the
5498 same in modes with signed zeros, since multiplying a
5499 negative value by 0 gives -0, not +0. */
5500 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
5501 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0)))
5502 && real_zerop (arg1))
5503 return omit_one_operand (type, arg1, arg0);
5504 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
5505 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5506 && real_onep (arg1))
5507 return non_lvalue (convert (type, arg0));
5509 /* Transform x * -1.0 into -x. */
5510 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5511 && real_minus_onep (arg1))
5512 return fold (build1 (NEGATE_EXPR, type, arg0));
5515 if (! wins && real_twop (arg1)
5516 && (*lang_hooks.decls.global_bindings_p) () == 0
5517 && ! contains_placeholder_p (arg0))
5519 tree arg = save_expr (arg0);
5520 return build (PLUS_EXPR, type, arg, arg);
5527 if (integer_all_onesp (arg1))
5528 return omit_one_operand (type, arg1, arg0);
5529 if (integer_zerop (arg1))
5530 return non_lvalue (convert (type, arg0));
5531 t1 = distribute_bit_expr (code, type, arg0, arg1);
5532 if (t1 != NULL_TREE)
5535 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
5537 This results in more efficient code for machines without a NAND
5538 instruction. Combine will canonicalize to the first form
5539 which will allow use of NAND instructions provided by the
5540 backend if they exist. */
5541 if (TREE_CODE (arg0) == BIT_NOT_EXPR
5542 && TREE_CODE (arg1) == BIT_NOT_EXPR)
5544 return fold (build1 (BIT_NOT_EXPR, type,
5545 build (BIT_AND_EXPR, type,
5546 TREE_OPERAND (arg0, 0),
5547 TREE_OPERAND (arg1, 0))));
5550 /* See if this can be simplified into a rotate first. If that
5551 is unsuccessful continue in the association code. */
5555 if (integer_zerop (arg1))
5556 return non_lvalue (convert (type, arg0));
5557 if (integer_all_onesp (arg1))
5558 return fold (build1 (BIT_NOT_EXPR, type, arg0));
5560 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
5561 with a constant, and the two constants have no bits in common,
5562 we should treat this as a BIT_IOR_EXPR since this may produce more
5564 if (TREE_CODE (arg0) == BIT_AND_EXPR
5565 && TREE_CODE (arg1) == BIT_AND_EXPR
5566 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5567 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
5568 && integer_zerop (const_binop (BIT_AND_EXPR,
5569 TREE_OPERAND (arg0, 1),
5570 TREE_OPERAND (arg1, 1), 0)))
5572 code = BIT_IOR_EXPR;
5576 /* See if this can be simplified into a rotate first. If that
5577 is unsuccessful continue in the association code. */
5582 if (integer_all_onesp (arg1))
5583 return non_lvalue (convert (type, arg0));
5584 if (integer_zerop (arg1))
5585 return omit_one_operand (type, arg1, arg0);
5586 t1 = distribute_bit_expr (code, type, arg0, arg1);
5587 if (t1 != NULL_TREE)
5589 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
5590 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
5591 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
5594 = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
5596 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
5597 && (~TREE_INT_CST_LOW (arg1)
5598 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
5599 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
5602 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
5604 This results in more efficient code for machines without a NOR
5605 instruction. Combine will canonicalize to the first form
5606 which will allow use of NOR instructions provided by the
5607 backend if they exist. */
5608 if (TREE_CODE (arg0) == BIT_NOT_EXPR
5609 && TREE_CODE (arg1) == BIT_NOT_EXPR)
5611 return fold (build1 (BIT_NOT_EXPR, type,
5612 build (BIT_IOR_EXPR, type,
5613 TREE_OPERAND (arg0, 0),
5614 TREE_OPERAND (arg1, 0))));
5619 case BIT_ANDTC_EXPR:
5620 if (integer_all_onesp (arg0))
5621 return non_lvalue (convert (type, arg1));
5622 if (integer_zerop (arg0))
5623 return omit_one_operand (type, arg0, arg1);
5624 if (TREE_CODE (arg1) == INTEGER_CST)
5626 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
5627 code = BIT_AND_EXPR;
5633 /* Don't touch a floating-point divide by zero unless the mode
5634 of the constant can represent infinity. */
5635 if (TREE_CODE (arg1) == REAL_CST
5636 && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg1)))
5637 && real_zerop (arg1))
5640 /* (-A) / (-B) -> A / B */
5641 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
5642 return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
5643 TREE_OPERAND (arg1, 0)));
5645 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
5646 if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
5647 && real_onep (arg1))
5648 return non_lvalue (convert (type, arg0));
5650 /* If ARG1 is a constant, we can convert this to a multiply by the
5651 reciprocal. This does not have the same rounding properties,
5652 so only do this if -funsafe-math-optimizations. We can actually
5653 always safely do it if ARG1 is a power of two, but it's hard to
5654 tell if it is or not in a portable manner. */
5655 if (TREE_CODE (arg1) == REAL_CST)
5657 if (flag_unsafe_math_optimizations
5658 && 0 != (tem = const_binop (code, build_real (type, dconst1),
5660 return fold (build (MULT_EXPR, type, arg0, tem));
5661 /* Find the reciprocal if optimizing and the result is exact. */
5665 r = TREE_REAL_CST (arg1);
5666 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
5668 tem = build_real (type, r);
5669 return fold (build (MULT_EXPR, type, arg0, tem));
5673 /* Convert A/B/C to A/(B*C). */
5674 if (flag_unsafe_math_optimizations
5675 && TREE_CODE (arg0) == RDIV_EXPR)
5677 return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
5678 build (MULT_EXPR, type, TREE_OPERAND (arg0, 1),
5681 /* Convert A/(B/C) to (A/B)*C. */
5682 if (flag_unsafe_math_optimizations
5683 && TREE_CODE (arg1) == RDIV_EXPR)
5685 return fold (build (MULT_EXPR, type,
5686 build (RDIV_EXPR, type, arg0,
5687 TREE_OPERAND (arg1, 0)),
5688 TREE_OPERAND (arg1, 1)));
5692 case TRUNC_DIV_EXPR:
5693 case ROUND_DIV_EXPR:
5694 case FLOOR_DIV_EXPR:
5696 case EXACT_DIV_EXPR:
5697 if (integer_onep (arg1))
5698 return non_lvalue (convert (type, arg0));
5699 if (integer_zerop (arg1))
5702 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
5703 operation, EXACT_DIV_EXPR.
5705 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
5706 At one time others generated faster code, it's not clear if they do
5707 after the last round to changes to the DIV code in expmed.c. */
5708 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
5709 && multiple_of_p (type, arg0, arg1))
5710 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
5712 if (TREE_CODE (arg1) == INTEGER_CST
5713 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5715 return convert (type, tem);
5720 case FLOOR_MOD_EXPR:
5721 case ROUND_MOD_EXPR:
5722 case TRUNC_MOD_EXPR:
5723 if (integer_onep (arg1))
5724 return omit_one_operand (type, integer_zero_node, arg0);
5725 if (integer_zerop (arg1))
5728 if (TREE_CODE (arg1) == INTEGER_CST
5729 && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
5731 return convert (type, tem);
5739 if (integer_zerop (arg1))
5740 return non_lvalue (convert (type, arg0));
5741 /* Since negative shift count is not well-defined,
5742 don't try to compute it in the compiler. */
5743 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
5745 /* Rewrite an LROTATE_EXPR by a constant into an
5746 RROTATE_EXPR by a new constant. */
5747 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
5749 TREE_SET_CODE (t, RROTATE_EXPR);
5750 code = RROTATE_EXPR;
5751 TREE_OPERAND (t, 1) = arg1
5754 convert (TREE_TYPE (arg1),
5755 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
5757 if (tree_int_cst_sgn (arg1) < 0)
5761 /* If we have a rotate of a bit operation with the rotate count and
5762 the second operand of the bit operation both constant,
5763 permute the two operations. */
5764 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5765 && (TREE_CODE (arg0) == BIT_AND_EXPR
5766 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
5767 || TREE_CODE (arg0) == BIT_IOR_EXPR
5768 || TREE_CODE (arg0) == BIT_XOR_EXPR)
5769 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
5770 return fold (build (TREE_CODE (arg0), type,
5771 fold (build (code, type,
5772 TREE_OPERAND (arg0, 0), arg1)),
5773 fold (build (code, type,
5774 TREE_OPERAND (arg0, 1), arg1))));
5776 /* Two consecutive rotates adding up to the width of the mode can
5778 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
5779 && TREE_CODE (arg0) == RROTATE_EXPR
5780 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5781 && TREE_INT_CST_HIGH (arg1) == 0
5782 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
5783 && ((TREE_INT_CST_LOW (arg1)
5784 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
5785 == (unsigned int) GET_MODE_BITSIZE (TYPE_MODE (type))))
5786 return TREE_OPERAND (arg0, 0);
5791 if (operand_equal_p (arg0, arg1, 0))
5792 return omit_one_operand (type, arg0, arg1);
5793 if (INTEGRAL_TYPE_P (type)
5794 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
5795 return omit_one_operand (type, arg1, arg0);
5799 if (operand_equal_p (arg0, arg1, 0))
5800 return omit_one_operand (type, arg0, arg1);
5801 if (INTEGRAL_TYPE_P (type)
5802 && TYPE_MAX_VALUE (type)
5803 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
5804 return omit_one_operand (type, arg1, arg0);
5807 case TRUTH_NOT_EXPR:
5808 /* Note that the operand of this must be an int
5809 and its values must be 0 or 1.
5810 ("true" is a fixed value perhaps depending on the language,
5811 but we don't handle values other than 1 correctly yet.) */
5812 tem = invert_truthvalue (arg0);
5813 /* Avoid infinite recursion. */
5814 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
5816 return convert (type, tem);
5818 case TRUTH_ANDIF_EXPR:
5819 /* Note that the operands of this must be ints
5820 and their values must be 0 or 1.
5821 ("true" is a fixed value perhaps depending on the language.) */
5822 /* If first arg is constant zero, return it. */
5823 if (integer_zerop (arg0))
5824 return convert (type, arg0);
5825 case TRUTH_AND_EXPR:
5826 /* If either arg is constant true, drop it. */
5827 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5828 return non_lvalue (convert (type, arg1));
5829 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)
5830 /* Preserve sequence points. */
5831 && (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
5832 return non_lvalue (convert (type, arg0));
5833 /* If second arg is constant zero, result is zero, but first arg
5834 must be evaluated. */
5835 if (integer_zerop (arg1))
5836 return omit_one_operand (type, arg1, arg0);
5837 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
5838 case will be handled here. */
5839 if (integer_zerop (arg0))
5840 return omit_one_operand (type, arg0, arg1);
5843 /* We only do these simplifications if we are optimizing. */
5847 /* Check for things like (A || B) && (A || C). We can convert this
5848 to A || (B && C). Note that either operator can be any of the four
5849 truth and/or operations and the transformation will still be
5850 valid. Also note that we only care about order for the
5851 ANDIF and ORIF operators. If B contains side effects, this
5852 might change the truth-value of A. */
5853 if (TREE_CODE (arg0) == TREE_CODE (arg1)
5854 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
5855 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
5856 || TREE_CODE (arg0) == TRUTH_AND_EXPR
5857 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
5858 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
5860 tree a00 = TREE_OPERAND (arg0, 0);
5861 tree a01 = TREE_OPERAND (arg0, 1);
5862 tree a10 = TREE_OPERAND (arg1, 0);
5863 tree a11 = TREE_OPERAND (arg1, 1);
5864 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5865 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5866 && (code == TRUTH_AND_EXPR
5867 || code == TRUTH_OR_EXPR));
5869 if (operand_equal_p (a00, a10, 0))
5870 return fold (build (TREE_CODE (arg0), type, a00,
5871 fold (build (code, type, a01, a11))));
5872 else if (commutative && operand_equal_p (a00, a11, 0))
5873 return fold (build (TREE_CODE (arg0), type, a00,
5874 fold (build (code, type, a01, a10))));
5875 else if (commutative && operand_equal_p (a01, a10, 0))
5876 return fold (build (TREE_CODE (arg0), type, a01,
5877 fold (build (code, type, a00, a11))));
5879 /* This case if tricky because we must either have commutative
5880 operators or else A10 must not have side-effects. */
5882 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
5883 && operand_equal_p (a01, a11, 0))
5884 return fold (build (TREE_CODE (arg0), type,
5885 fold (build (code, type, a00, a10)),
5889 /* See if we can build a range comparison. */
5890 if (0 != (tem = fold_range_test (t)))
5893 /* Check for the possibility of merging component references. If our
5894 lhs is another similar operation, try to merge its rhs with our
5895 rhs. Then try to merge our lhs and rhs. */
5896 if (TREE_CODE (arg0) == code
5897 && 0 != (tem = fold_truthop (code, type,
5898 TREE_OPERAND (arg0, 1), arg1)))
5899 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
5901 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
5906 case TRUTH_ORIF_EXPR:
5907 /* Note that the operands of this must be ints
5908 and their values must be 0 or true.
5909 ("true" is a fixed value perhaps depending on the language.) */
5910 /* If first arg is constant true, return it. */
5911 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5912 return convert (type, arg0);
5914 /* If either arg is constant zero, drop it. */
5915 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
5916 return non_lvalue (convert (type, arg1));
5917 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)
5918 /* Preserve sequence points. */
5919 && (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
5920 return non_lvalue (convert (type, arg0));
5921 /* If second arg is constant true, result is true, but we must
5922 evaluate first arg. */
5923 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5924 return omit_one_operand (type, arg1, arg0);
5925 /* Likewise for first arg, but note this only occurs here for
5927 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5928 return omit_one_operand (type, arg0, arg1);
5931 case TRUTH_XOR_EXPR:
5932 /* If either arg is constant zero, drop it. */
5933 if (integer_zerop (arg0))
5934 return non_lvalue (convert (type, arg1));
5935 if (integer_zerop (arg1))
5936 return non_lvalue (convert (type, arg0));
5937 /* If either arg is constant true, this is a logical inversion. */
5938 if (integer_onep (arg0))
5939 return non_lvalue (convert (type, invert_truthvalue (arg1)));
5940 if (integer_onep (arg1))
5941 return non_lvalue (convert (type, invert_truthvalue (arg0)));
5950 /* If one arg is a real or integer constant, put it last. */
5951 if ((TREE_CODE (arg0) == INTEGER_CST
5952 && TREE_CODE (arg1) != INTEGER_CST)
5953 || (TREE_CODE (arg0) == REAL_CST
5954 && TREE_CODE (arg0) != REAL_CST))
5956 TREE_OPERAND (t, 0) = arg1;
5957 TREE_OPERAND (t, 1) = arg0;
5958 arg0 = TREE_OPERAND (t, 0);
5959 arg1 = TREE_OPERAND (t, 1);
5960 code = swap_tree_comparison (code);
5961 TREE_SET_CODE (t, code);
5964 if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
5966 /* (-a) CMP (-b) -> b CMP a */
5967 if (TREE_CODE (arg0) == NEGATE_EXPR
5968 && TREE_CODE (arg1) == NEGATE_EXPR)
5969 return fold (build (code, type, TREE_OPERAND (arg1, 0),
5970 TREE_OPERAND (arg0, 0)));
5971 /* (-a) CMP CST -> a swap(CMP) (-CST) */
5972 if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
5975 (swap_tree_comparison (code), type,
5976 TREE_OPERAND (arg0, 0),
5977 build_real (TREE_TYPE (arg1),
5978 REAL_VALUE_NEGATE (TREE_REAL_CST (arg1)))));
5979 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
5980 /* a CMP (-0) -> a CMP 0 */
5981 if (TREE_CODE (arg1) == REAL_CST
5982 && REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
5983 return fold (build (code, type, arg0,
5984 build_real (TREE_TYPE (arg1), dconst0)));
5986 /* If this is a comparison of a real constant with a PLUS_EXPR
5987 or a MINUS_EXPR of a real constant, we can convert it into a
5988 comparison with a revised real constant as long as no overflow
5989 occurs when unsafe_math_optimizations are enabled. */
5990 if (flag_unsafe_math_optimizations
5991 && TREE_CODE (arg1) == REAL_CST
5992 && (TREE_CODE (arg0) == PLUS_EXPR
5993 || TREE_CODE (arg0) == MINUS_EXPR)
5994 && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
5995 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
5996 ? MINUS_EXPR : PLUS_EXPR,
5997 arg1, TREE_OPERAND (arg0, 1), 0))
5998 && ! TREE_CONSTANT_OVERFLOW (tem))
5999 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6002 /* Convert foo++ == CONST into ++foo == CONST + INCR.
6003 First, see if one arg is constant; find the constant arg
6004 and the other one. */
6006 tree constop = 0, varop = NULL_TREE;
6007 int constopnum = -1;
6009 if (TREE_CONSTANT (arg1))
6010 constopnum = 1, constop = arg1, varop = arg0;
6011 if (TREE_CONSTANT (arg0))
6012 constopnum = 0, constop = arg0, varop = arg1;
6014 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
6016 /* This optimization is invalid for ordered comparisons
6017 if CONST+INCR overflows or if foo+incr might overflow.
6018 This optimization is invalid for floating point due to rounding.
6019 For pointer types we assume overflow doesn't happen. */
6020 if (POINTER_TYPE_P (TREE_TYPE (varop))
6021 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
6022 && (code == EQ_EXPR || code == NE_EXPR)))
6025 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
6026 constop, TREE_OPERAND (varop, 1)));
6028 /* Do not overwrite the current varop to be a preincrement,
6029 create a new node so that we won't confuse our caller who
6030 might create trees and throw them away, reusing the
6031 arguments that they passed to build. This shows up in
6032 the THEN or ELSE parts of ?: being postincrements. */
6033 varop = build (PREINCREMENT_EXPR, TREE_TYPE (varop),
6034 TREE_OPERAND (varop, 0),
6035 TREE_OPERAND (varop, 1));
6037 /* If VAROP is a reference to a bitfield, we must mask
6038 the constant by the width of the field. */
6039 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
6040 && DECL_BIT_FIELD(TREE_OPERAND
6041 (TREE_OPERAND (varop, 0), 1)))
6044 = TREE_INT_CST_LOW (DECL_SIZE
6046 (TREE_OPERAND (varop, 0), 1)));
6047 tree mask, unsigned_type;
6048 unsigned int precision;
6049 tree folded_compare;
6051 /* First check whether the comparison would come out
6052 always the same. If we don't do that we would
6053 change the meaning with the masking. */
6054 if (constopnum == 0)
6055 folded_compare = fold (build (code, type, constop,
6056 TREE_OPERAND (varop, 0)));
6058 folded_compare = fold (build (code, type,
6059 TREE_OPERAND (varop, 0),
6061 if (integer_zerop (folded_compare)
6062 || integer_onep (folded_compare))
6063 return omit_one_operand (type, folded_compare, varop);
6065 unsigned_type = (*lang_hooks.types.type_for_size)(size, 1);
6066 precision = TYPE_PRECISION (unsigned_type);
6067 mask = build_int_2 (~0, ~0);
6068 TREE_TYPE (mask) = unsigned_type;
6069 force_fit_type (mask, 0);
6070 mask = const_binop (RSHIFT_EXPR, mask,
6071 size_int (precision - size), 0);
6072 newconst = fold (build (BIT_AND_EXPR,
6073 TREE_TYPE (varop), newconst,
6074 convert (TREE_TYPE (varop),
6078 t = build (code, type,
6079 (constopnum == 0) ? newconst : varop,
6080 (constopnum == 1) ? newconst : varop);
6084 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
6086 if (POINTER_TYPE_P (TREE_TYPE (varop))
6087 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
6088 && (code == EQ_EXPR || code == NE_EXPR)))
6091 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
6092 constop, TREE_OPERAND (varop, 1)));
6094 /* Do not overwrite the current varop to be a predecrement,
6095 create a new node so that we won't confuse our caller who
6096 might create trees and throw them away, reusing the
6097 arguments that they passed to build. This shows up in
6098 the THEN or ELSE parts of ?: being postdecrements. */
6099 varop = build (PREDECREMENT_EXPR, TREE_TYPE (varop),
6100 TREE_OPERAND (varop, 0),
6101 TREE_OPERAND (varop, 1));
6103 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
6104 && DECL_BIT_FIELD(TREE_OPERAND
6105 (TREE_OPERAND (varop, 0), 1)))
6108 = TREE_INT_CST_LOW (DECL_SIZE
6110 (TREE_OPERAND (varop, 0), 1)));
6111 tree mask, unsigned_type;
6112 unsigned int precision;
6113 tree folded_compare;
6115 if (constopnum == 0)
6116 folded_compare = fold (build (code, type, constop,
6117 TREE_OPERAND (varop, 0)));
6119 folded_compare = fold (build (code, type,
6120 TREE_OPERAND (varop, 0),
6122 if (integer_zerop (folded_compare)
6123 || integer_onep (folded_compare))
6124 return omit_one_operand (type, folded_compare, varop);
6126 unsigned_type = (*lang_hooks.types.type_for_size)(size, 1);
6127 precision = TYPE_PRECISION (unsigned_type);
6128 mask = build_int_2 (~0, ~0);
6129 TREE_TYPE (mask) = TREE_TYPE (varop);
6130 force_fit_type (mask, 0);
6131 mask = const_binop (RSHIFT_EXPR, mask,
6132 size_int (precision - size), 0);
6133 newconst = fold (build (BIT_AND_EXPR,
6134 TREE_TYPE (varop), newconst,
6135 convert (TREE_TYPE (varop),
6139 t = build (code, type,
6140 (constopnum == 0) ? newconst : varop,
6141 (constopnum == 1) ? newconst : varop);
6147 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
6148 This transformation affects the cases which are handled in later
6149 optimizations involving comparisons with non-negative constants. */
6150 if (TREE_CODE (arg1) == INTEGER_CST
6151 && TREE_CODE (arg0) != INTEGER_CST
6152 && tree_int_cst_sgn (arg1) > 0)
6158 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6159 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6164 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6165 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6173 /* Comparisons with the highest or lowest possible integer of
6174 the specified size will have known values. */
6176 int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1)));
6178 if (TREE_CODE (arg1) == INTEGER_CST
6179 && ! TREE_CONSTANT_OVERFLOW (arg1)
6180 && width <= HOST_BITS_PER_WIDE_INT
6181 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
6182 || POINTER_TYPE_P (TREE_TYPE (arg1))))
6184 unsigned HOST_WIDE_INT signed_max;
6185 unsigned HOST_WIDE_INT max, min;
6187 signed_max = ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1;
6189 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6191 max = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
6197 min = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
6200 if (TREE_INT_CST_HIGH (arg1) == 0
6201 && TREE_INT_CST_LOW (arg1) == max)
6205 return omit_one_operand (type,
6206 convert (type, integer_zero_node),
6210 TREE_SET_CODE (t, EQ_EXPR);
6213 return omit_one_operand (type,
6214 convert (type, integer_one_node),
6218 TREE_SET_CODE (t, NE_EXPR);
6221 /* The GE_EXPR and LT_EXPR cases above are not normally
6222 reached because of previous transformations. */
6227 else if (TREE_INT_CST_HIGH (arg1) == 0
6228 && TREE_INT_CST_LOW (arg1) == max - 1)
6233 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
6234 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6238 arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
6239 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6244 else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
6245 && TREE_INT_CST_LOW (arg1) == min)
6249 return omit_one_operand (type,
6250 convert (type, integer_zero_node),
6254 TREE_SET_CODE (t, EQ_EXPR);
6258 return omit_one_operand (type,
6259 convert (type, integer_one_node),
6263 TREE_SET_CODE (t, NE_EXPR);
6269 else if (TREE_INT_CST_HIGH (arg1) == (min ? -1 : 0)
6270 && TREE_INT_CST_LOW (arg1) == min + 1)
6275 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6276 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6280 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
6281 t = build (code, type, TREE_OPERAND (t, 0), arg1);
6287 else if (TREE_INT_CST_HIGH (arg1) == 0
6288 && TREE_INT_CST_LOW (arg1) == signed_max
6289 && TREE_UNSIGNED (TREE_TYPE (arg1))
6290 /* signed_type does not work on pointer types. */
6291 && INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
6293 /* The following case also applies to X < signed_max+1
6294 and X >= signed_max+1 because previous transformations. */
6295 if (code == LE_EXPR || code == GT_EXPR)
6298 st0 = (*lang_hooks.types.signed_type) (TREE_TYPE (arg0));
6299 st1 = (*lang_hooks.types.signed_type) (TREE_TYPE (arg1));
6301 (build (code == LE_EXPR ? GE_EXPR: LT_EXPR,
6302 type, convert (st0, arg0),
6303 convert (st1, integer_zero_node)));
6309 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
6310 a MINUS_EXPR of a constant, we can convert it into a comparison with
6311 a revised constant as long as no overflow occurs. */
6312 if ((code == EQ_EXPR || code == NE_EXPR)
6313 && TREE_CODE (arg1) == INTEGER_CST
6314 && (TREE_CODE (arg0) == PLUS_EXPR
6315 || TREE_CODE (arg0) == MINUS_EXPR)
6316 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
6317 && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
6318 ? MINUS_EXPR : PLUS_EXPR,
6319 arg1, TREE_OPERAND (arg0, 1), 0))
6320 && ! TREE_CONSTANT_OVERFLOW (tem))
6321 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6323 /* Similarly for a NEGATE_EXPR. */
6324 else if ((code == EQ_EXPR || code == NE_EXPR)
6325 && TREE_CODE (arg0) == NEGATE_EXPR
6326 && TREE_CODE (arg1) == INTEGER_CST
6327 && 0 != (tem = negate_expr (arg1))
6328 && TREE_CODE (tem) == INTEGER_CST
6329 && ! TREE_CONSTANT_OVERFLOW (tem))
6330 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
6332 /* If we have X - Y == 0, we can convert that to X == Y and similarly
6333 for !=. Don't do this for ordered comparisons due to overflow. */
6334 else if ((code == NE_EXPR || code == EQ_EXPR)
6335 && integer_zerop (arg1) && TREE_CODE (arg0) == MINUS_EXPR)
6336 return fold (build (code, type,
6337 TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)));
6339 /* If we are widening one operand of an integer comparison,
6340 see if the other operand is similarly being widened. Perhaps we
6341 can do the comparison in the narrower type. */
6342 else if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE
6343 && TREE_CODE (arg0) == NOP_EXPR
6344 && (tem = get_unwidened (arg0, NULL_TREE)) != arg0
6345 && (t1 = get_unwidened (arg1, TREE_TYPE (tem))) != 0
6346 && (TREE_TYPE (t1) == TREE_TYPE (tem)
6347 || (TREE_CODE (t1) == INTEGER_CST
6348 && int_fits_type_p (t1, TREE_TYPE (tem)))))
6349 return fold (build (code, type, tem, convert (TREE_TYPE (tem), t1)));
6351 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
6352 constant, we can simplify it. */
6353 else if (TREE_CODE (arg1) == INTEGER_CST
6354 && (TREE_CODE (arg0) == MIN_EXPR
6355 || TREE_CODE (arg0) == MAX_EXPR)
6356 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
6357 return optimize_minmax_comparison (t);
6359 /* If we are comparing an ABS_EXPR with a constant, we can
6360 convert all the cases into explicit comparisons, but they may
6361 well not be faster than doing the ABS and one comparison.
6362 But ABS (X) <= C is a range comparison, which becomes a subtraction
6363 and a comparison, and is probably faster. */
6364 else if (code == LE_EXPR && TREE_CODE (arg1) == INTEGER_CST
6365 && TREE_CODE (arg0) == ABS_EXPR
6366 && ! TREE_SIDE_EFFECTS (arg0)
6367 && (0 != (tem = negate_expr (arg1)))
6368 && TREE_CODE (tem) == INTEGER_CST
6369 && ! TREE_CONSTANT_OVERFLOW (tem))
6370 return fold (build (TRUTH_ANDIF_EXPR, type,
6371 build (GE_EXPR, type, TREE_OPERAND (arg0, 0), tem),
6372 build (LE_EXPR, type,
6373 TREE_OPERAND (arg0, 0), arg1)));
6375 /* If this is an EQ or NE comparison with zero and ARG0 is
6376 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
6377 two operations, but the latter can be done in one less insn
6378 on machines that have only two-operand insns or on which a
6379 constant cannot be the first operand. */
6380 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
6381 && TREE_CODE (arg0) == BIT_AND_EXPR)
6383 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
6384 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
6386 fold (build (code, type,
6387 build (BIT_AND_EXPR, TREE_TYPE (arg0),
6389 TREE_TYPE (TREE_OPERAND (arg0, 0)),
6390 TREE_OPERAND (arg0, 1),
6391 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
6392 convert (TREE_TYPE (arg0),
6395 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
6396 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
6398 fold (build (code, type,
6399 build (BIT_AND_EXPR, TREE_TYPE (arg0),
6401 TREE_TYPE (TREE_OPERAND (arg0, 1)),
6402 TREE_OPERAND (arg0, 0),
6403 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
6404 convert (TREE_TYPE (arg0),
6409 /* If this is an NE or EQ comparison of zero against the result of a
6410 signed MOD operation whose second operand is a power of 2, make
6411 the MOD operation unsigned since it is simpler and equivalent. */
6412 if ((code == NE_EXPR || code == EQ_EXPR)
6413 && integer_zerop (arg1)
6414 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
6415 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
6416 || TREE_CODE (arg0) == CEIL_MOD_EXPR
6417 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
6418 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
6419 && integer_pow2p (TREE_OPERAND (arg0, 1)))
6421 tree newtype = (*lang_hooks.types.unsigned_type) (TREE_TYPE (arg0));
6422 tree newmod = build (TREE_CODE (arg0), newtype,
6423 convert (newtype, TREE_OPERAND (arg0, 0)),
6424 convert (newtype, TREE_OPERAND (arg0, 1)));
6426 return build (code, type, newmod, convert (newtype, arg1));
6429 /* If this is an NE comparison of zero with an AND of one, remove the
6430 comparison since the AND will give the correct value. */
6431 if (code == NE_EXPR && integer_zerop (arg1)
6432 && TREE_CODE (arg0) == BIT_AND_EXPR
6433 && integer_onep (TREE_OPERAND (arg0, 1)))
6434 return convert (type, arg0);
6436 /* If we have (A & C) == C where C is a power of 2, convert this into
6437 (A & C) != 0. Similarly for NE_EXPR. */
6438 if ((code == EQ_EXPR || code == NE_EXPR)
6439 && TREE_CODE (arg0) == BIT_AND_EXPR
6440 && integer_pow2p (TREE_OPERAND (arg0, 1))
6441 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
6442 return fold (build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
6443 arg0, integer_zero_node));
6445 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6446 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6447 if ((code == EQ_EXPR || code == NE_EXPR)
6448 && TREE_CODE (arg0) == BIT_AND_EXPR
6449 && integer_zerop (arg1))
6451 tree arg00 = sign_bit_p (TREE_OPERAND (arg0, 0),
6452 TREE_OPERAND (arg0, 1));
6453 if (arg00 != NULL_TREE)
6455 tree stype = (*lang_hooks.types.signed_type) (TREE_TYPE (arg00));
6456 return fold (build (code == EQ_EXPR ? GE_EXPR : LT_EXPR, type,
6457 convert (stype, arg00),
6458 convert (stype, integer_zero_node)));
6462 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
6463 and similarly for >= into !=. */
6464 if ((code == LT_EXPR || code == GE_EXPR)
6465 && TREE_UNSIGNED (TREE_TYPE (arg0))
6466 && TREE_CODE (arg1) == LSHIFT_EXPR
6467 && integer_onep (TREE_OPERAND (arg1, 0)))
6468 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
6469 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
6470 TREE_OPERAND (arg1, 1)),
6471 convert (TREE_TYPE (arg0), integer_zero_node));
6473 else if ((code == LT_EXPR || code == GE_EXPR)
6474 && TREE_UNSIGNED (TREE_TYPE (arg0))
6475 && (TREE_CODE (arg1) == NOP_EXPR
6476 || TREE_CODE (arg1) == CONVERT_EXPR)
6477 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
6478 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
6480 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
6481 convert (TREE_TYPE (arg0),
6482 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
6483 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
6484 convert (TREE_TYPE (arg0), integer_zero_node));
6486 /* Simplify comparison of something with itself. (For IEEE
6487 floating-point, we can only do some of these simplifications.) */
6488 if (operand_equal_p (arg0, arg1, 0))
6495 if (! FLOAT_TYPE_P (TREE_TYPE (arg0)))
6496 return constant_boolean_node (1, type);
6498 TREE_SET_CODE (t, code);
6502 /* For NE, we can only do this simplification if integer. */
6503 if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
6505 /* ... fall through ... */
6508 return constant_boolean_node (0, type);
6514 /* If we are comparing an expression that just has comparisons
6515 of two integer values, arithmetic expressions of those comparisons,
6516 and constants, we can simplify it. There are only three cases
6517 to check: the two values can either be equal, the first can be
6518 greater, or the second can be greater. Fold the expression for
6519 those three values. Since each value must be 0 or 1, we have
6520 eight possibilities, each of which corresponds to the constant 0
6521 or 1 or one of the six possible comparisons.
6523 This handles common cases like (a > b) == 0 but also handles
6524 expressions like ((x > y) - (y > x)) > 0, which supposedly
6525 occur in macroized code. */
6527 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
6529 tree cval1 = 0, cval2 = 0;
6532 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
6533 /* Don't handle degenerate cases here; they should already
6534 have been handled anyway. */
6535 && cval1 != 0 && cval2 != 0
6536 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
6537 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
6538 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
6539 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
6540 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
6541 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
6542 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
6544 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
6545 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
6547 /* We can't just pass T to eval_subst in case cval1 or cval2
6548 was the same as ARG1. */
6551 = fold (build (code, type,
6552 eval_subst (arg0, cval1, maxval, cval2, minval),
6555 = fold (build (code, type,
6556 eval_subst (arg0, cval1, maxval, cval2, maxval),
6559 = fold (build (code, type,
6560 eval_subst (arg0, cval1, minval, cval2, maxval),
6563 /* All three of these results should be 0 or 1. Confirm they
6564 are. Then use those values to select the proper code
6567 if ((integer_zerop (high_result)
6568 || integer_onep (high_result))
6569 && (integer_zerop (equal_result)
6570 || integer_onep (equal_result))
6571 && (integer_zerop (low_result)
6572 || integer_onep (low_result)))
6574 /* Make a 3-bit mask with the high-order bit being the
6575 value for `>', the next for '=', and the low for '<'. */
6576 switch ((integer_onep (high_result) * 4)
6577 + (integer_onep (equal_result) * 2)
6578 + integer_onep (low_result))
6582 return omit_one_operand (type, integer_zero_node, arg0);
6603 return omit_one_operand (type, integer_one_node, arg0);
6606 t = build (code, type, cval1, cval2);
6608 return save_expr (t);
6615 /* If this is a comparison of a field, we may be able to simplify it. */
6616 if (((TREE_CODE (arg0) == COMPONENT_REF
6617 && (*lang_hooks.can_use_bit_fields_p) ())
6618 || TREE_CODE (arg0) == BIT_FIELD_REF)
6619 && (code == EQ_EXPR || code == NE_EXPR)
6620 /* Handle the constant case even without -O
6621 to make sure the warnings are given. */
6622 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
6624 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
6628 /* If this is a comparison of complex values and either or both sides
6629 are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
6630 comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
6631 This may prevent needless evaluations. */
6632 if ((code == EQ_EXPR || code == NE_EXPR)
6633 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
6634 && (TREE_CODE (arg0) == COMPLEX_EXPR
6635 || TREE_CODE (arg1) == COMPLEX_EXPR
6636 || TREE_CODE (arg0) == COMPLEX_CST
6637 || TREE_CODE (arg1) == COMPLEX_CST))
6639 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
6640 tree real0, imag0, real1, imag1;
6642 arg0 = save_expr (arg0);
6643 arg1 = save_expr (arg1);
6644 real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
6645 imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
6646 real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
6647 imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
6649 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
6652 fold (build (code, type, real0, real1)),
6653 fold (build (code, type, imag0, imag1))));
6656 /* Optimize comparisons of strlen vs zero to a compare of the
6657 first character of the string vs zero. To wit,
6658 strlen(ptr) == 0 => *ptr == 0
6659 strlen(ptr) != 0 => *ptr != 0
6660 Other cases should reduce to one of these two (or a constant)
6661 due to the return value of strlen being unsigned. */
6662 if ((code == EQ_EXPR || code == NE_EXPR)
6663 && integer_zerop (arg1)
6664 && TREE_CODE (arg0) == CALL_EXPR
6665 && TREE_CODE (TREE_OPERAND (arg0, 0)) == ADDR_EXPR)
6667 tree fndecl = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
6670 if (TREE_CODE (fndecl) == FUNCTION_DECL
6671 && DECL_BUILT_IN (fndecl)
6672 && DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_MD
6673 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STRLEN
6674 && (arglist = TREE_OPERAND (arg0, 1))
6675 && TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) == POINTER_TYPE
6676 && ! TREE_CHAIN (arglist))
6677 return fold (build (code, type,
6678 build1 (INDIRECT_REF, char_type_node,
6679 TREE_VALUE(arglist)),
6680 integer_zero_node));
6683 /* From here on, the only cases we handle are when the result is
6684 known to be a constant.
6686 To compute GT, swap the arguments and do LT.
6687 To compute GE, do LT and invert the result.
6688 To compute LE, swap the arguments, do LT and invert the result.
6689 To compute NE, do EQ and invert the result.
6691 Therefore, the code below must handle only EQ and LT. */
6693 if (code == LE_EXPR || code == GT_EXPR)
6695 tem = arg0, arg0 = arg1, arg1 = tem;
6696 code = swap_tree_comparison (code);
6699 /* Note that it is safe to invert for real values here because we
6700 will check below in the one case that it matters. */
6704 if (code == NE_EXPR || code == GE_EXPR)
6707 code = invert_tree_comparison (code);
6710 /* Compute a result for LT or EQ if args permit;
6711 otherwise return T. */
6712 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
6714 if (code == EQ_EXPR)
6715 t1 = build_int_2 (tree_int_cst_equal (arg0, arg1), 0);
6717 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
6718 ? INT_CST_LT_UNSIGNED (arg0, arg1)
6719 : INT_CST_LT (arg0, arg1)),
6723 #if 0 /* This is no longer useful, but breaks some real code. */
6724 /* Assume a nonexplicit constant cannot equal an explicit one,
6725 since such code would be undefined anyway.
6726 Exception: on sysvr4, using #pragma weak,
6727 a label can come out as 0. */
6728 else if (TREE_CODE (arg1) == INTEGER_CST
6729 && !integer_zerop (arg1)
6730 && TREE_CONSTANT (arg0)
6731 && TREE_CODE (arg0) == ADDR_EXPR
6733 t1 = build_int_2 (0, 0);
6735 /* Two real constants can be compared explicitly. */
6736 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
6738 /* If either operand is a NaN, the result is false with two
6739 exceptions: First, an NE_EXPR is true on NaNs, but that case
6740 is already handled correctly since we will be inverting the
6741 result for NE_EXPR. Second, if we had inverted a LE_EXPR
6742 or a GE_EXPR into a LT_EXPR, we must return true so that it
6743 will be inverted into false. */
6745 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
6746 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
6747 t1 = build_int_2 (invert && code == LT_EXPR, 0);
6749 else if (code == EQ_EXPR)
6750 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
6751 TREE_REAL_CST (arg1)),
6754 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
6755 TREE_REAL_CST (arg1)),
6759 if (t1 == NULL_TREE)
6763 TREE_INT_CST_LOW (t1) ^= 1;
6765 TREE_TYPE (t1) = type;
6766 if (TREE_CODE (type) == BOOLEAN_TYPE)
6767 return (*lang_hooks.truthvalue_conversion) (t1);
6771 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
6772 so all simple results must be passed through pedantic_non_lvalue. */
6773 if (TREE_CODE (arg0) == INTEGER_CST)
6774 return pedantic_non_lvalue
6775 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
6776 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
6777 return pedantic_omit_one_operand (type, arg1, arg0);
6779 /* If the second operand is zero, invert the comparison and swap
6780 the second and third operands. Likewise if the second operand
6781 is constant and the third is not or if the third operand is
6782 equivalent to the first operand of the comparison. */
6784 if (integer_zerop (arg1)
6785 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
6786 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6787 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6788 TREE_OPERAND (t, 2),
6789 TREE_OPERAND (arg0, 1))))
6791 /* See if this can be inverted. If it can't, possibly because
6792 it was a floating-point inequality comparison, don't do
6794 tem = invert_truthvalue (arg0);
6796 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
6798 t = build (code, type, tem,
6799 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
6801 /* arg1 should be the first argument of the new T. */
6802 arg1 = TREE_OPERAND (t, 1);
6807 /* If we have A op B ? A : C, we may be able to convert this to a
6808 simpler expression, depending on the operation and the values
6809 of B and C. Signed zeros prevent all of these transformations,
6810 for reasons given above each one. */
6812 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
6813 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
6814 arg1, TREE_OPERAND (arg0, 1))
6815 && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1))))
6817 tree arg2 = TREE_OPERAND (t, 2);
6818 enum tree_code comp_code = TREE_CODE (arg0);
6822 /* If we have A op 0 ? A : -A, consider applying the following
6825 A == 0? A : -A same as -A
6826 A != 0? A : -A same as A
6827 A >= 0? A : -A same as abs (A)
6828 A > 0? A : -A same as abs (A)
6829 A <= 0? A : -A same as -abs (A)
6830 A < 0? A : -A same as -abs (A)
6832 None of these transformations work for modes with signed
6833 zeros. If A is +/-0, the first two transformations will
6834 change the sign of the result (from +0 to -0, or vice
6835 versa). The last four will fix the sign of the result,
6836 even though the original expressions could be positive or
6837 negative, depending on the sign of A.
6839 Note that all these transformations are correct if A is
6840 NaN, since the two alternatives (A and -A) are also NaNs. */
6841 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
6842 ? real_zerop (TREE_OPERAND (arg0, 1))
6843 : integer_zerop (TREE_OPERAND (arg0, 1)))
6844 && TREE_CODE (arg2) == NEGATE_EXPR
6845 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
6853 (convert (TREE_TYPE (TREE_OPERAND (t, 1)),
6856 return pedantic_non_lvalue (convert (type, arg1));
6859 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6860 arg1 = convert ((*lang_hooks.types.signed_type)
6861 (TREE_TYPE (arg1)), arg1);
6862 return pedantic_non_lvalue
6863 (convert (type, fold (build1 (ABS_EXPR,
6864 TREE_TYPE (arg1), arg1))));
6867 if (TREE_UNSIGNED (TREE_TYPE (arg1)))
6868 arg1 = convert ((lang_hooks.types.signed_type)
6869 (TREE_TYPE (arg1)), arg1);
6870 return pedantic_non_lvalue
6871 (negate_expr (convert (type,
6872 fold (build1 (ABS_EXPR,
6879 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
6880 A == 0 ? A : 0 is always 0 unless A is -0. Note that
6881 both transformations are correct when A is NaN: A != 0
6882 is then true, and A == 0 is false. */
6884 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
6886 if (comp_code == NE_EXPR)
6887 return pedantic_non_lvalue (convert (type, arg1));
6888 else if (comp_code == EQ_EXPR)
6889 return pedantic_non_lvalue (convert (type, integer_zero_node));
6892 /* Try some transformations of A op B ? A : B.
6894 A == B? A : B same as B
6895 A != B? A : B same as A
6896 A >= B? A : B same as max (A, B)
6897 A > B? A : B same as max (B, A)
6898 A <= B? A : B same as min (A, B)
6899 A < B? A : B same as min (B, A)
6901 As above, these transformations don't work in the presence
6902 of signed zeros. For example, if A and B are zeros of
6903 opposite sign, the first two transformations will change
6904 the sign of the result. In the last four, the original
6905 expressions give different results for (A=+0, B=-0) and
6906 (A=-0, B=+0), but the transformed expressions do not.
6908 The first two transformations are correct if either A or B
6909 is a NaN. In the first transformation, the condition will
6910 be false, and B will indeed be chosen. In the case of the
6911 second transformation, the condition A != B will be true,
6912 and A will be chosen.
6914 The conversions to max() and min() are not correct if B is
6915 a number and A is not. The conditions in the original
6916 expressions will be false, so all four give B. The min()
6917 and max() versions would give a NaN instead. */
6918 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
6919 arg2, TREE_OPERAND (arg0, 0)))
6921 tree comp_op0 = TREE_OPERAND (arg0, 0);
6922 tree comp_op1 = TREE_OPERAND (arg0, 1);
6923 tree comp_type = TREE_TYPE (comp_op0);
6925 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
6926 if (TYPE_MAIN_VARIANT (comp_type) == TYPE_MAIN_VARIANT (type))
6932 return pedantic_non_lvalue (convert (type, arg2));
6934 return pedantic_non_lvalue (convert (type, arg1));
6937 /* In C++ a ?: expression can be an lvalue, so put the
6938 operand which will be used if they are equal first
6939 so that we can convert this back to the
6940 corresponding COND_EXPR. */
6941 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))))
6942 return pedantic_non_lvalue
6943 (convert (type, fold (build (MIN_EXPR, comp_type,
6944 (comp_code == LE_EXPR
6945 ? comp_op0 : comp_op1),
6946 (comp_code == LE_EXPR
6947 ? comp_op1 : comp_op0)))));
6951 if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg1))))
6952 return pedantic_non_lvalue
6953 (convert (type, fold (build (MAX_EXPR, comp_type,
6954 (comp_code == GE_EXPR
6955 ? comp_op0 : comp_op1),
6956 (comp_code == GE_EXPR
6957 ? comp_op1 : comp_op0)))));
6964 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
6965 we might still be able to simplify this. For example,
6966 if C1 is one less or one more than C2, this might have started
6967 out as a MIN or MAX and been transformed by this function.
6968 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
6970 if (INTEGRAL_TYPE_P (type)
6971 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
6972 && TREE_CODE (arg2) == INTEGER_CST)
6976 /* We can replace A with C1 in this case. */
6977 arg1 = convert (type, TREE_OPERAND (arg0, 1));
6978 t = build (code, type, TREE_OPERAND (t, 0), arg1,
6979 TREE_OPERAND (t, 2));
6983 /* If C1 is C2 + 1, this is min(A, C2). */
6984 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
6985 && operand_equal_p (TREE_OPERAND (arg0, 1),
6986 const_binop (PLUS_EXPR, arg2,
6987 integer_one_node, 0), 1))
6988 return pedantic_non_lvalue
6989 (fold (build (MIN_EXPR, type, arg1, arg2)));
6993 /* If C1 is C2 - 1, this is min(A, C2). */
6994 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
6995 && operand_equal_p (TREE_OPERAND (arg0, 1),
6996 const_binop (MINUS_EXPR, arg2,
6997 integer_one_node, 0), 1))
6998 return pedantic_non_lvalue
6999 (fold (build (MIN_EXPR, type, arg1, arg2)));
7003 /* If C1 is C2 - 1, this is max(A, C2). */
7004 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
7005 && operand_equal_p (TREE_OPERAND (arg0, 1),
7006 const_binop (MINUS_EXPR, arg2,
7007 integer_one_node, 0), 1))
7008 return pedantic_non_lvalue
7009 (fold (build (MAX_EXPR, type, arg1, arg2)));
7013 /* If C1 is C2 + 1, this is max(A, C2). */
7014 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
7015 && operand_equal_p (TREE_OPERAND (arg0, 1),
7016 const_binop (PLUS_EXPR, arg2,
7017 integer_one_node, 0), 1))
7018 return pedantic_non_lvalue
7019 (fold (build (MAX_EXPR, type, arg1, arg2)));
7028 /* If the second operand is simpler than the third, swap them
7029 since that produces better jump optimization results. */
7030 if ((TREE_CONSTANT (arg1) || DECL_P (arg1)
7031 || TREE_CODE (arg1) == SAVE_EXPR)
7032 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
7033 || DECL_P (TREE_OPERAND (t, 2))
7034 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
7036 /* See if this can be inverted. If it can't, possibly because
7037 it was a floating-point inequality comparison, don't do
7039 tem = invert_truthvalue (arg0);
7041 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
7043 t = build (code, type, tem,
7044 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
7046 /* arg1 should be the first argument of the new T. */
7047 arg1 = TREE_OPERAND (t, 1);
7052 /* Convert A ? 1 : 0 to simply A. */
7053 if (integer_onep (TREE_OPERAND (t, 1))
7054 && integer_zerop (TREE_OPERAND (t, 2))
7055 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
7056 call to fold will try to move the conversion inside
7057 a COND, which will recurse. In that case, the COND_EXPR
7058 is probably the best choice, so leave it alone. */
7059 && type == TREE_TYPE (arg0))
7060 return pedantic_non_lvalue (arg0);
7062 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
7063 over COND_EXPR in cases such as floating point comparisons. */
7064 if (integer_zerop (TREE_OPERAND (t, 1))
7065 && integer_onep (TREE_OPERAND (t, 2))
7066 && truth_value_p (TREE_CODE (arg0)))
7067 return pedantic_non_lvalue (convert (type,
7068 invert_truthvalue (arg0)));
7070 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
7071 operation is simply A & 2. */
7073 if (integer_zerop (TREE_OPERAND (t, 2))
7074 && TREE_CODE (arg0) == NE_EXPR
7075 && integer_zerop (TREE_OPERAND (arg0, 1))
7076 && integer_pow2p (arg1)
7077 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
7078 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
7080 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
7082 /* Convert A ? B : 0 into A && B if A and B are truth values. */
7083 if (integer_zerop (TREE_OPERAND (t, 2))
7084 && truth_value_p (TREE_CODE (arg0))
7085 && truth_value_p (TREE_CODE (arg1)))
7086 return pedantic_non_lvalue (fold (build (TRUTH_ANDIF_EXPR, type,
7089 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
7090 if (integer_onep (TREE_OPERAND (t, 2))
7091 && truth_value_p (TREE_CODE (arg0))
7092 && truth_value_p (TREE_CODE (arg1)))
7094 /* Only perform transformation if ARG0 is easily inverted. */
7095 tem = invert_truthvalue (arg0);
7096 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
7097 return pedantic_non_lvalue (fold (build (TRUTH_ORIF_EXPR, type,
7104 /* When pedantic, a compound expression can be neither an lvalue
7105 nor an integer constant expression. */
7106 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
7108 /* Don't let (0, 0) be null pointer constant. */
7109 if (integer_zerop (arg1))
7110 return build1 (NOP_EXPR, type, arg1);
7111 return convert (type, arg1);
7115 return build_complex (type, arg0, arg1);
7119 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
7121 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
7122 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
7123 TREE_OPERAND (arg0, 1));
7124 else if (TREE_CODE (arg0) == COMPLEX_CST)
7125 return TREE_REALPART (arg0);
7126 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
7127 return fold (build (TREE_CODE (arg0), type,
7128 fold (build1 (REALPART_EXPR, type,
7129 TREE_OPERAND (arg0, 0))),
7130 fold (build1 (REALPART_EXPR,
7131 type, TREE_OPERAND (arg0, 1)))));
7135 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
7136 return convert (type, integer_zero_node);
7137 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
7138 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
7139 TREE_OPERAND (arg0, 0));
7140 else if (TREE_CODE (arg0) == COMPLEX_CST)
7141 return TREE_IMAGPART (arg0);
7142 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
7143 return fold (build (TREE_CODE (arg0), type,
7144 fold (build1 (IMAGPART_EXPR, type,
7145 TREE_OPERAND (arg0, 0))),
7146 fold (build1 (IMAGPART_EXPR, type,
7147 TREE_OPERAND (arg0, 1)))));
7150 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
7152 case CLEANUP_POINT_EXPR:
7153 if (! has_cleanups (arg0))
7154 return TREE_OPERAND (t, 0);
7157 enum tree_code code0 = TREE_CODE (arg0);
7158 int kind0 = TREE_CODE_CLASS (code0);
7159 tree arg00 = TREE_OPERAND (arg0, 0);
7162 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
7163 return fold (build1 (code0, type,
7164 fold (build1 (CLEANUP_POINT_EXPR,
7165 TREE_TYPE (arg00), arg00))));
7167 if (kind0 == '<' || kind0 == '2'
7168 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
7169 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
7170 || code0 == TRUTH_XOR_EXPR)
7172 arg01 = TREE_OPERAND (arg0, 1);
7174 if (TREE_CONSTANT (arg00)
7175 || ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
7176 && ! has_cleanups (arg00)))
7177 return fold (build (code0, type, arg00,
7178 fold (build1 (CLEANUP_POINT_EXPR,
7179 TREE_TYPE (arg01), arg01))));
7181 if (TREE_CONSTANT (arg01))
7182 return fold (build (code0, type,
7183 fold (build1 (CLEANUP_POINT_EXPR,
7184 TREE_TYPE (arg00), arg00)),
7192 /* Check for a built-in function. */
7193 if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR
7194 && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (expr, 0), 0))
7196 && DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (expr, 0), 0)))
7198 tree tmp = fold_builtin (expr);
7206 } /* switch (code) */
7209 /* Determine if first argument is a multiple of second argument. Return 0 if
7210 it is not, or we cannot easily determined it to be.
7212 An example of the sort of thing we care about (at this point; this routine
7213 could surely be made more general, and expanded to do what the *_DIV_EXPR's
7214 fold cases do now) is discovering that
7216 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
7222 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
7224 This code also handles discovering that
7226 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
7228 is a multiple of 8 so we don't have to worry about dealing with a
7231 Note that we *look* inside a SAVE_EXPR only to determine how it was
7232 calculated; it is not safe for fold to do much of anything else with the
7233 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
7234 at run time. For example, the latter example above *cannot* be implemented
7235 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
7236 evaluation time of the original SAVE_EXPR is not necessarily the same at
7237 the time the new expression is evaluated. The only optimization of this
7238 sort that would be valid is changing
7240 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
7244 SAVE_EXPR (I) * SAVE_EXPR (J)
7246 (where the same SAVE_EXPR (J) is used in the original and the
7247 transformed version). */
7250 multiple_of_p (type, top, bottom)
7255 if (operand_equal_p (top, bottom, 0))
7258 if (TREE_CODE (type) != INTEGER_TYPE)
7261 switch (TREE_CODE (top))
7264 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
7265 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
7269 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
7270 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
7273 if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST)
7277 op1 = TREE_OPERAND (top, 1);
7278 /* const_binop may not detect overflow correctly,
7279 so check for it explicitly here. */
7280 if (TYPE_PRECISION (TREE_TYPE (size_one_node))
7281 > TREE_INT_CST_LOW (op1)
7282 && TREE_INT_CST_HIGH (op1) == 0
7283 && 0 != (t1 = convert (type,
7284 const_binop (LSHIFT_EXPR, size_one_node,
7286 && ! TREE_OVERFLOW (t1))
7287 return multiple_of_p (type, t1, bottom);
7292 /* Can't handle conversions from non-integral or wider integral type. */
7293 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
7294 || (TYPE_PRECISION (type)
7295 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
7298 /* .. fall through ... */
7301 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
7304 if (TREE_CODE (bottom) != INTEGER_CST
7305 || (TREE_UNSIGNED (type)
7306 && (tree_int_cst_sgn (top) < 0
7307 || tree_int_cst_sgn (bottom) < 0)))
7309 return integer_zerop (const_binop (TRUNC_MOD_EXPR,
7317 /* Return true if `t' is known to be non-negative. */
7320 tree_expr_nonnegative_p (t)
7323 switch (TREE_CODE (t))
7329 return tree_int_cst_sgn (t) >= 0;
7330 case TRUNC_DIV_EXPR:
7332 case FLOOR_DIV_EXPR:
7333 case ROUND_DIV_EXPR:
7334 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7335 && tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7336 case TRUNC_MOD_EXPR:
7338 case FLOOR_MOD_EXPR:
7339 case ROUND_MOD_EXPR:
7340 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7342 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
7343 && tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
7345 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7347 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7348 && tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7350 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
7351 || tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7353 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7355 return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
7357 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7358 case NON_LVALUE_EXPR:
7359 return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
7361 return rtl_expr_nonnegative_p (RTL_EXPR_RTL (t));
7364 if (truth_value_p (TREE_CODE (t)))
7365 /* Truth values evaluate to 0 or 1, which is nonnegative. */
7368 /* We don't know sign of `t', so be conservative and return false. */
7373 /* Return true if `r' is known to be non-negative.
7374 Only handles constants at the moment. */
7377 rtl_expr_nonnegative_p (r)
7380 switch (GET_CODE (r))
7383 return INTVAL (r) >= 0;
7386 if (GET_MODE (r) == VOIDmode)
7387 return CONST_DOUBLE_HIGH (r) >= 0;
7395 units = CONST_VECTOR_NUNITS (r);
7397 for (i = 0; i < units; ++i)
7399 elt = CONST_VECTOR_ELT (r, i);
7400 if (!rtl_expr_nonnegative_p (elt))
7409 /* These are always nonnegative. */
7417 #include "gt-fold-const.h"