1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /*@@ This file should be rewritten to use an arbitrary precision
22 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
23 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
24 @@ The routines that translate from the ap rep should
25 @@ warn if precision et. al. is lost.
26 @@ This would also make life easier when this technology is used
27 @@ 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. */
51 /* Handle floating overflow for `const_binop'. */
52 static jmp_buf float_error;
54 static void encode PROTO((HOST_WIDE_INT *,
55 HOST_WIDE_INT, HOST_WIDE_INT));
56 static void decode PROTO((HOST_WIDE_INT *,
57 HOST_WIDE_INT *, HOST_WIDE_INT *));
58 int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
59 HOST_WIDE_INT, HOST_WIDE_INT,
60 HOST_WIDE_INT, HOST_WIDE_INT *,
61 HOST_WIDE_INT *, HOST_WIDE_INT *,
63 static int split_tree PROTO((tree, enum tree_code, tree *,
65 static tree int_const_binop PROTO((enum tree_code, tree, tree, int, int));
66 static tree const_binop PROTO((enum tree_code, tree, tree, int));
67 static tree fold_convert PROTO((tree, tree));
68 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
69 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
70 static int truth_value_p PROTO((enum tree_code));
71 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
72 static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
73 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
74 static tree omit_one_operand PROTO((tree, tree, tree));
75 static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
76 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
77 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
78 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
80 static tree decode_field_reference PROTO((tree, int *, int *,
81 enum machine_mode *, int *,
82 int *, tree *, tree *));
83 static int all_ones_mask_p PROTO((tree, int));
84 static int simple_operand_p PROTO((tree));
85 static tree range_binop PROTO((enum tree_code, tree, tree, int,
87 static tree make_range PROTO((tree, int *, tree *, tree *));
88 static tree build_range_check PROTO((tree, tree, int, tree, tree));
89 static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
91 static tree fold_range_test PROTO((tree));
92 static tree unextend PROTO((tree, int, int, tree));
93 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
94 static tree strip_compound_expr PROTO((tree, tree));
95 static int multiple_of_p PROTO((tree, tree, tree));
101 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
102 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
103 Then this yields nonzero if overflow occurred during the addition.
104 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
105 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
106 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
108 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
109 We do that by representing the two-word integer in 4 words, with only
110 HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
113 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
114 #define HIGHPART(x) \
115 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
116 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
118 /* Unpack a two-word integer into 4 words.
119 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
120 WORDS points to the array of HOST_WIDE_INTs. */
123 encode (words, low, hi)
124 HOST_WIDE_INT *words;
125 HOST_WIDE_INT low, hi;
127 words[0] = LOWPART (low);
128 words[1] = HIGHPART (low);
129 words[2] = LOWPART (hi);
130 words[3] = HIGHPART (hi);
133 /* Pack an array of 4 words into a two-word integer.
134 WORDS points to the array of words.
135 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
138 decode (words, low, hi)
139 HOST_WIDE_INT *words;
140 HOST_WIDE_INT *low, *hi;
142 *low = words[0] | words[1] * BASE;
143 *hi = words[2] | words[3] * BASE;
146 /* Make the integer constant T valid for its type
147 by setting to 0 or 1 all the bits in the constant
148 that don't belong in the type.
149 Yield 1 if a signed overflow occurs, 0 otherwise.
150 If OVERFLOW is nonzero, a signed overflow has already occurred
151 in calculating T, so propagate it.
153 Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
157 force_fit_type (t, overflow)
161 HOST_WIDE_INT low, high;
164 if (TREE_CODE (t) == REAL_CST)
166 #ifdef CHECK_FLOAT_VALUE
167 CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
173 else if (TREE_CODE (t) != INTEGER_CST)
176 low = TREE_INT_CST_LOW (t);
177 high = TREE_INT_CST_HIGH (t);
179 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
182 prec = TYPE_PRECISION (TREE_TYPE (t));
184 /* First clear all bits that are beyond the type's precision. */
186 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
188 else if (prec > HOST_BITS_PER_WIDE_INT)
190 TREE_INT_CST_HIGH (t)
191 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
195 TREE_INT_CST_HIGH (t) = 0;
196 if (prec < HOST_BITS_PER_WIDE_INT)
197 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
200 /* Unsigned types do not suffer sign extension or overflow. */
201 if (TREE_UNSIGNED (TREE_TYPE (t)))
204 /* If the value's sign bit is set, extend the sign. */
205 if (prec != 2 * HOST_BITS_PER_WIDE_INT
206 && (prec > HOST_BITS_PER_WIDE_INT
207 ? (TREE_INT_CST_HIGH (t)
208 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
209 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
211 /* Value is negative:
212 set to 1 all the bits that are outside this type's precision. */
213 if (prec > HOST_BITS_PER_WIDE_INT)
215 TREE_INT_CST_HIGH (t)
216 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
220 TREE_INT_CST_HIGH (t) = -1;
221 if (prec < HOST_BITS_PER_WIDE_INT)
222 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
226 /* Yield nonzero if signed overflow occurred. */
228 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
232 /* Add two doubleword integers with doubleword result.
233 Each argument is given as two `HOST_WIDE_INT' pieces.
234 One argument is L1 and H1; the other, L2 and H2.
235 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
238 add_double (l1, h1, l2, h2, lv, hv)
239 HOST_WIDE_INT l1, h1, l2, h2;
240 HOST_WIDE_INT *lv, *hv;
245 h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
249 return overflow_sum_sign (h1, h2, h);
252 /* Negate a doubleword integer with doubleword result.
253 Return nonzero if the operation overflows, assuming it's signed.
254 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
255 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
258 neg_double (l1, h1, lv, hv)
259 HOST_WIDE_INT l1, h1;
260 HOST_WIDE_INT *lv, *hv;
266 return (*hv & h1) < 0;
276 /* Multiply two doubleword integers with doubleword result.
277 Return nonzero if the operation overflows, assuming it's signed.
278 Each argument is given as two `HOST_WIDE_INT' pieces.
279 One argument is L1 and H1; the other, L2 and H2.
280 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
283 mul_double (l1, h1, l2, h2, lv, hv)
284 HOST_WIDE_INT l1, h1, l2, h2;
285 HOST_WIDE_INT *lv, *hv;
287 HOST_WIDE_INT arg1[4];
288 HOST_WIDE_INT arg2[4];
289 HOST_WIDE_INT prod[4 * 2];
290 register unsigned HOST_WIDE_INT carry;
291 register int i, j, k;
292 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
294 encode (arg1, l1, h1);
295 encode (arg2, l2, h2);
297 bzero ((char *) prod, sizeof prod);
299 for (i = 0; i < 4; i++)
302 for (j = 0; j < 4; j++)
305 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
306 carry += arg1[i] * arg2[j];
307 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
309 prod[k] = LOWPART (carry);
310 carry = HIGHPART (carry);
315 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
317 /* Check for overflow by calculating the top half of the answer in full;
318 it should agree with the low half's sign bit. */
319 decode (prod+4, &toplow, &tophigh);
322 neg_double (l2, h2, &neglow, &neghigh);
323 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
327 neg_double (l1, h1, &neglow, &neghigh);
328 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
330 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
333 /* Shift the doubleword integer in L1, H1 left by COUNT places
334 keeping only PREC bits of result.
335 Shift right if COUNT is negative.
336 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
337 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
340 lshift_double (l1, h1, count, prec, lv, hv, arith)
341 HOST_WIDE_INT l1, h1, count;
343 HOST_WIDE_INT *lv, *hv;
348 rshift_double (l1, h1, - count, prec, lv, hv, arith);
352 #ifdef SHIFT_COUNT_TRUNCATED
353 if (SHIFT_COUNT_TRUNCATED)
357 if (count >= HOST_BITS_PER_WIDE_INT)
359 *hv = (unsigned HOST_WIDE_INT) l1 << (count - HOST_BITS_PER_WIDE_INT);
364 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
365 | ((unsigned HOST_WIDE_INT) l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
366 *lv = (unsigned HOST_WIDE_INT) l1 << count;
370 /* Shift the doubleword integer in L1, H1 right by COUNT places
371 keeping only PREC bits of result. COUNT must be positive.
372 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
373 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
376 rshift_double (l1, h1, count, prec, lv, hv, arith)
377 HOST_WIDE_INT l1, h1, count;
379 HOST_WIDE_INT *lv, *hv;
382 unsigned HOST_WIDE_INT signmask;
384 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
387 #ifdef SHIFT_COUNT_TRUNCATED
388 if (SHIFT_COUNT_TRUNCATED)
392 if (count >= HOST_BITS_PER_WIDE_INT)
395 *lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1)
396 | ((unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT)));
400 *lv = (((unsigned HOST_WIDE_INT) l1 >> count)
401 | ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
402 *hv = ((signmask << (HOST_BITS_PER_WIDE_INT - count))
403 | ((unsigned HOST_WIDE_INT) h1 >> count));
407 /* Rotate the doubleword integer in L1, H1 left by COUNT places
408 keeping only PREC bits of result.
409 Rotate right if COUNT is negative.
410 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
413 lrotate_double (l1, h1, count, prec, lv, hv)
414 HOST_WIDE_INT l1, h1, count;
416 HOST_WIDE_INT *lv, *hv;
418 HOST_WIDE_INT s1l, s1h, s2l, s2h;
424 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
425 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
430 /* Rotate the doubleword integer in L1, H1 left by COUNT places
431 keeping only PREC bits of result. COUNT must be positive.
432 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
435 rrotate_double (l1, h1, count, prec, lv, hv)
436 HOST_WIDE_INT l1, h1, count;
438 HOST_WIDE_INT *lv, *hv;
440 HOST_WIDE_INT s1l, s1h, s2l, s2h;
446 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
447 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
452 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
453 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
454 CODE is a tree code for a kind of division, one of
455 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
457 It controls how the quotient is rounded to a integer.
458 Return nonzero if the operation overflows.
459 UNS nonzero says do unsigned division. */
462 div_and_round_double (code, uns,
463 lnum_orig, hnum_orig, lden_orig, hden_orig,
464 lquo, hquo, lrem, hrem)
467 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
468 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
469 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
472 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
473 HOST_WIDE_INT den[4], quo[4];
475 unsigned HOST_WIDE_INT work;
476 register unsigned HOST_WIDE_INT carry = 0;
477 HOST_WIDE_INT lnum = lnum_orig;
478 HOST_WIDE_INT hnum = hnum_orig;
479 HOST_WIDE_INT lden = lden_orig;
480 HOST_WIDE_INT hden = hden_orig;
483 if ((hden == 0) && (lden == 0))
484 overflow = 1, lden = 1;
486 /* calculate quotient sign and convert operands to unsigned. */
492 /* (minimum integer) / (-1) is the only overflow case. */
493 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
499 neg_double (lden, hden, &lden, &hden);
503 if (hnum == 0 && hden == 0)
504 { /* single precision */
506 /* This unsigned division rounds toward zero. */
507 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
512 { /* trivial case: dividend < divisor */
513 /* hden != 0 already checked. */
520 bzero ((char *) quo, sizeof quo);
522 bzero ((char *) num, sizeof num); /* to zero 9th element */
523 bzero ((char *) den, sizeof den);
525 encode (num, lnum, hnum);
526 encode (den, lden, hden);
528 /* Special code for when the divisor < BASE. */
529 if (hden == 0 && lden < BASE)
531 /* hnum != 0 already checked. */
532 for (i = 4 - 1; i >= 0; i--)
534 work = num[i] + carry * BASE;
535 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
536 carry = work % (unsigned HOST_WIDE_INT) lden;
541 /* Full double precision division,
542 with thanks to Don Knuth's "Seminumerical Algorithms". */
543 int num_hi_sig, den_hi_sig;
544 unsigned HOST_WIDE_INT quo_est, scale;
546 /* Find the highest non-zero divisor digit. */
547 for (i = 4 - 1; ; i--)
553 /* Insure that the first digit of the divisor is at least BASE/2.
554 This is required by the quotient digit estimation algorithm. */
556 scale = BASE / (den[den_hi_sig] + 1);
557 if (scale > 1) { /* scale divisor and dividend */
559 for (i = 0; i <= 4 - 1; i++) {
560 work = (num[i] * scale) + carry;
561 num[i] = LOWPART (work);
562 carry = HIGHPART (work);
565 for (i = 0; i <= 4 - 1; i++) {
566 work = (den[i] * scale) + carry;
567 den[i] = LOWPART (work);
568 carry = HIGHPART (work);
569 if (den[i] != 0) den_hi_sig = i;
576 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
577 /* guess the next quotient digit, quo_est, by dividing the first
578 two remaining dividend digits by the high order quotient digit.
579 quo_est is never low and is at most 2 high. */
580 unsigned HOST_WIDE_INT tmp;
582 num_hi_sig = i + den_hi_sig + 1;
583 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
584 if (num[num_hi_sig] != den[den_hi_sig])
585 quo_est = work / den[den_hi_sig];
589 /* refine quo_est so it's usually correct, and at most one high. */
590 tmp = work - quo_est * den[den_hi_sig];
592 && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
595 /* Try QUO_EST as the quotient digit, by multiplying the
596 divisor by QUO_EST and subtracting from the remaining dividend.
597 Keep in mind that QUO_EST is the I - 1st digit. */
600 for (j = 0; j <= den_hi_sig; j++)
602 work = quo_est * den[j] + carry;
603 carry = HIGHPART (work);
604 work = num[i + j] - LOWPART (work);
605 num[i + j] = LOWPART (work);
606 carry += HIGHPART (work) != 0;
609 /* if quo_est was high by one, then num[i] went negative and
610 we need to correct things. */
612 if (num[num_hi_sig] < carry)
615 carry = 0; /* add divisor back in */
616 for (j = 0; j <= den_hi_sig; j++)
618 work = num[i + j] + den[j] + carry;
619 carry = HIGHPART (work);
620 num[i + j] = LOWPART (work);
622 num [num_hi_sig] += carry;
625 /* store the quotient digit. */
630 decode (quo, lquo, hquo);
633 /* if result is negative, make it so. */
635 neg_double (*lquo, *hquo, lquo, hquo);
637 /* compute trial remainder: rem = num - (quo * den) */
638 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
639 neg_double (*lrem, *hrem, lrem, hrem);
640 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
645 case TRUNC_MOD_EXPR: /* round toward zero */
646 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
650 case FLOOR_MOD_EXPR: /* round toward negative infinity */
651 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
654 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
657 else return overflow;
661 case CEIL_MOD_EXPR: /* round toward positive infinity */
662 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
664 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
667 else return overflow;
671 case ROUND_MOD_EXPR: /* round to closest integer */
673 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
674 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
676 /* get absolute values */
677 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
678 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
680 /* if (2 * abs (lrem) >= abs (lden)) */
681 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
682 labs_rem, habs_rem, <wice, &htwice);
683 if (((unsigned HOST_WIDE_INT) habs_den
684 < (unsigned HOST_WIDE_INT) htwice)
685 || (((unsigned HOST_WIDE_INT) habs_den
686 == (unsigned HOST_WIDE_INT) htwice)
687 && ((HOST_WIDE_INT unsigned) labs_den
688 < (unsigned HOST_WIDE_INT) ltwice)))
692 add_double (*lquo, *hquo,
693 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
696 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
699 else return overflow;
707 /* compute true remainder: rem = num - (quo * den) */
708 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
709 neg_double (*lrem, *hrem, lrem, hrem);
710 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
714 #ifndef REAL_ARITHMETIC
715 /* Effectively truncate a real value to represent the nearest possible value
716 in a narrower mode. The result is actually represented in the same data
717 type as the argument, but its value is usually different.
719 A trap may occur during the FP operations and it is the responsibility
720 of the calling function to have a handler established. */
723 real_value_truncate (mode, arg)
724 enum machine_mode mode;
727 return REAL_VALUE_TRUNCATE (mode, arg);
730 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
732 /* Check for infinity in an IEEE double precision number. */
738 /* The IEEE 64-bit double format. */
743 unsigned exponent : 11;
744 unsigned mantissa1 : 20;
749 unsigned mantissa1 : 20;
750 unsigned exponent : 11;
756 if (u.big_endian.sign == 1)
759 return (u.big_endian.exponent == 2047
760 && u.big_endian.mantissa1 == 0
761 && u.big_endian.mantissa2 == 0);
766 return (u.little_endian.exponent == 2047
767 && u.little_endian.mantissa1 == 0
768 && u.little_endian.mantissa2 == 0);
772 /* Check whether an IEEE double precision number is a NaN. */
778 /* The IEEE 64-bit double format. */
783 unsigned exponent : 11;
784 unsigned mantissa1 : 20;
789 unsigned mantissa1 : 20;
790 unsigned exponent : 11;
796 if (u.big_endian.sign == 1)
799 return (u.big_endian.exponent == 2047
800 && (u.big_endian.mantissa1 != 0
801 || u.big_endian.mantissa2 != 0));
806 return (u.little_endian.exponent == 2047
807 && (u.little_endian.mantissa1 != 0
808 || u.little_endian.mantissa2 != 0));
812 /* Check for a negative IEEE double precision number. */
818 /* The IEEE 64-bit double format. */
823 unsigned exponent : 11;
824 unsigned mantissa1 : 20;
829 unsigned mantissa1 : 20;
830 unsigned exponent : 11;
836 if (u.big_endian.sign == 1)
839 return u.big_endian.sign;
844 return u.little_endian.sign;
847 #else /* Target not IEEE */
849 /* Let's assume other float formats don't have infinity.
850 (This can be overridden by redefining REAL_VALUE_ISINF.) */
858 /* Let's assume other float formats don't have NaNs.
859 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
867 /* Let's assume other float formats don't have minus zero.
868 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
875 #endif /* Target not IEEE */
877 /* Try to change R into its exact multiplicative inverse in machine mode
878 MODE. Return nonzero function value if successful. */
881 exact_real_inverse (mode, r)
882 enum machine_mode mode;
892 /* Usually disable if bounds checks are not reliable. */
893 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
896 /* Set array index to the less significant bits in the unions, depending
897 on the endian-ness of the host doubles.
898 Disable if insufficient information on the data structure. */
899 #if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
902 #if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
905 #if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
908 #define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
913 if (setjmp (float_error))
915 /* Don't do the optimization if there was an arithmetic error. */
917 set_float_handler (NULL_PTR);
920 set_float_handler (float_error);
922 /* Domain check the argument. */
928 if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
932 /* Compute the reciprocal and check for numerical exactness.
933 It is unnecessary to check all the significand bits to determine
934 whether X is a power of 2. If X is not, then it is impossible for
935 the bottom half significand of both X and 1/X to be all zero bits.
936 Hence we ignore the data structure of the top half and examine only
937 the low order bits of the two significands. */
939 if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
942 /* Truncate to the required mode and range-check the result. */
943 y.d = REAL_VALUE_TRUNCATE (mode, t.d);
944 #ifdef CHECK_FLOAT_VALUE
946 if (CHECK_FLOAT_VALUE (mode, y.d, i))
950 /* Fail if truncation changed the value. */
951 if (y.d != t.d || y.d == 0.0)
955 if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
959 /* Output the reciprocal and return success flag. */
960 set_float_handler (NULL_PTR);
964 #endif /* no REAL_ARITHMETIC */
966 /* Split a tree IN into a constant and a variable part
967 that could be combined with CODE to make IN.
968 CODE must be a commutative arithmetic operation.
969 Store the constant part into *CONP and the variable in &VARP.
970 Return 1 if this was done; zero means the tree IN did not decompose
973 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
974 Therefore, we must tell the caller whether the variable part
975 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
976 The value stored is the coefficient for the variable term.
977 The constant term we return should always be added;
978 we negate it if necessary. */
981 split_tree (in, code, varp, conp, varsignp)
987 register tree outtype = TREE_TYPE (in);
991 /* Strip any conversions that don't change the machine mode. */
992 while ((TREE_CODE (in) == NOP_EXPR
993 || TREE_CODE (in) == CONVERT_EXPR)
994 && (TYPE_MODE (TREE_TYPE (in))
995 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
996 in = TREE_OPERAND (in, 0);
998 if (TREE_CODE (in) == code
999 || (! FLOAT_TYPE_P (TREE_TYPE (in))
1000 /* We can associate addition and subtraction together
1001 (even though the C standard doesn't say so)
1002 for integers because the value is not affected.
1003 For reals, the value might be affected, so we can't. */
1004 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
1005 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1007 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1008 if (code == INTEGER_CST)
1010 *conp = TREE_OPERAND (in, 0);
1011 *varp = TREE_OPERAND (in, 1);
1012 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1013 && TREE_TYPE (*varp) != outtype)
1014 *varp = convert (outtype, *varp);
1015 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1018 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1020 *conp = TREE_OPERAND (in, 1);
1021 *varp = TREE_OPERAND (in, 0);
1023 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1024 && TREE_TYPE (*varp) != outtype)
1025 *varp = convert (outtype, *varp);
1026 if (TREE_CODE (in) == MINUS_EXPR)
1028 /* If operation is subtraction and constant is second,
1029 must negate it to get an additive constant.
1030 And this cannot be done unless it is a manifest constant.
1031 It could also be the address of a static variable.
1032 We cannot negate that, so give up. */
1033 if (TREE_CODE (*conp) == INTEGER_CST)
1034 /* Subtracting from integer_zero_node loses for long long. */
1035 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1041 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1043 *conp = TREE_OPERAND (in, 0);
1044 *varp = TREE_OPERAND (in, 1);
1045 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1046 && TREE_TYPE (*varp) != outtype)
1047 *varp = convert (outtype, *varp);
1048 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1055 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1056 to produce a new constant.
1058 If NOTRUNC is nonzero, do not truncate the result to fit the data type.
1059 If FORSIZE is nonzero, compute overflow for unsigned types. */
1062 int_const_binop (code, arg1, arg2, notrunc, forsize)
1063 enum tree_code code;
1064 register tree arg1, arg2;
1065 int notrunc, forsize;
1067 HOST_WIDE_INT int1l, int1h, int2l, int2h;
1068 HOST_WIDE_INT low, hi;
1069 HOST_WIDE_INT garbagel, garbageh;
1071 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1073 int no_overflow = 0;
1075 int1l = TREE_INT_CST_LOW (arg1);
1076 int1h = TREE_INT_CST_HIGH (arg1);
1077 int2l = TREE_INT_CST_LOW (arg2);
1078 int2h = TREE_INT_CST_HIGH (arg2);
1083 low = int1l | int2l, hi = int1h | int2h;
1087 low = int1l ^ int2l, hi = int1h ^ int2h;
1091 low = int1l & int2l, hi = int1h & int2h;
1094 case BIT_ANDTC_EXPR:
1095 low = int1l & ~int2l, hi = int1h & ~int2h;
1101 /* It's unclear from the C standard whether shifts can overflow.
1102 The following code ignores overflow; perhaps a C standard
1103 interpretation ruling is needed. */
1104 lshift_double (int1l, int1h, int2l,
1105 TYPE_PRECISION (TREE_TYPE (arg1)),
1114 lrotate_double (int1l, int1h, int2l,
1115 TYPE_PRECISION (TREE_TYPE (arg1)),
1120 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1124 neg_double (int2l, int2h, &low, &hi);
1125 add_double (int1l, int1h, low, hi, &low, &hi);
1126 overflow = overflow_sum_sign (hi, int2h, int1h);
1130 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1133 case TRUNC_DIV_EXPR:
1134 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1135 case EXACT_DIV_EXPR:
1136 /* This is a shortcut for a common special case. */
1137 if (int2h == 0 && int2l > 0
1138 && ! TREE_CONSTANT_OVERFLOW (arg1)
1139 && ! TREE_CONSTANT_OVERFLOW (arg2)
1140 && int1h == 0 && int1l >= 0)
1142 if (code == CEIL_DIV_EXPR)
1144 low = int1l / int2l, hi = 0;
1148 /* ... fall through ... */
1150 case ROUND_DIV_EXPR:
1151 if (int2h == 0 && int2l == 1)
1153 low = int1l, hi = int1h;
1156 if (int1l == int2l && int1h == int2h
1157 && ! (int1l == 0 && int1h == 0))
1162 overflow = div_and_round_double (code, uns,
1163 int1l, int1h, int2l, int2h,
1164 &low, &hi, &garbagel, &garbageh);
1167 case TRUNC_MOD_EXPR:
1168 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1169 /* This is a shortcut for a common special case. */
1170 if (int2h == 0 && int2l > 0
1171 && ! TREE_CONSTANT_OVERFLOW (arg1)
1172 && ! TREE_CONSTANT_OVERFLOW (arg2)
1173 && int1h == 0 && int1l >= 0)
1175 if (code == CEIL_MOD_EXPR)
1177 low = int1l % int2l, hi = 0;
1181 /* ... fall through ... */
1183 case ROUND_MOD_EXPR:
1184 overflow = div_and_round_double (code, uns,
1185 int1l, int1h, int2l, int2h,
1186 &garbagel, &garbageh, &low, &hi);
1193 low = (((unsigned HOST_WIDE_INT) int1h
1194 < (unsigned HOST_WIDE_INT) int2h)
1195 || (((unsigned HOST_WIDE_INT) int1h
1196 == (unsigned HOST_WIDE_INT) int2h)
1197 && ((unsigned HOST_WIDE_INT) int1l
1198 < (unsigned HOST_WIDE_INT) int2l)));
1202 low = ((int1h < int2h)
1203 || ((int1h == int2h)
1204 && ((unsigned HOST_WIDE_INT) int1l
1205 < (unsigned HOST_WIDE_INT) int2l)));
1207 if (low == (code == MIN_EXPR))
1208 low = int1l, hi = int1h;
1210 low = int2l, hi = int2h;
1217 if (TREE_TYPE (arg1) == sizetype && hi == 0
1219 && (TYPE_MAX_VALUE (sizetype) == NULL
1220 || low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)))
1222 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1226 t = build_int_2 (low, hi);
1227 TREE_TYPE (t) = TREE_TYPE (arg1);
1231 = ((notrunc ? (!uns || forsize) && overflow
1232 : force_fit_type (t, (!uns || forsize) && overflow) && ! no_overflow)
1233 | TREE_OVERFLOW (arg1)
1234 | TREE_OVERFLOW (arg2));
1235 /* If we're doing a size calculation, unsigned arithmetic does overflow.
1236 So check if force_fit_type truncated the value. */
1238 && ! TREE_OVERFLOW (t)
1239 && (TREE_INT_CST_HIGH (t) != hi
1240 || TREE_INT_CST_LOW (t) != low))
1241 TREE_OVERFLOW (t) = 1;
1242 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1243 | TREE_CONSTANT_OVERFLOW (arg1)
1244 | TREE_CONSTANT_OVERFLOW (arg2));
1248 /* Combine two constants ARG1 and ARG2 under operation CODE
1249 to produce a new constant.
1250 We assume ARG1 and ARG2 have the same data type,
1251 or at least are the same kind of constant and the same machine mode.
1253 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1256 const_binop (code, arg1, arg2, notrunc)
1257 enum tree_code code;
1258 register tree arg1, arg2;
1261 STRIP_NOPS (arg1); STRIP_NOPS (arg2);
1263 if (TREE_CODE (arg1) == INTEGER_CST)
1264 return int_const_binop (code, arg1, arg2, notrunc, 0);
1266 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1267 if (TREE_CODE (arg1) == REAL_CST)
1272 REAL_VALUE_TYPE value;
1275 d1 = TREE_REAL_CST (arg1);
1276 d2 = TREE_REAL_CST (arg2);
1278 /* If either operand is a NaN, just return it. Otherwise, set up
1279 for floating-point trap; we return an overflow. */
1280 if (REAL_VALUE_ISNAN (d1))
1282 else if (REAL_VALUE_ISNAN (d2))
1284 else if (setjmp (float_error))
1286 t = copy_node (arg1);
1291 set_float_handler (float_error);
1293 #ifdef REAL_ARITHMETIC
1294 REAL_ARITHMETIC (value, code, d1, d2);
1311 #ifndef REAL_INFINITY
1320 value = MIN (d1, d2);
1324 value = MAX (d1, d2);
1330 #endif /* no REAL_ARITHMETIC */
1331 t = build_real (TREE_TYPE (arg1),
1332 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1334 set_float_handler (NULL_PTR);
1337 = (force_fit_type (t, overflow)
1338 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1339 TREE_CONSTANT_OVERFLOW (t)
1341 | TREE_CONSTANT_OVERFLOW (arg1)
1342 | TREE_CONSTANT_OVERFLOW (arg2);
1345 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1346 if (TREE_CODE (arg1) == COMPLEX_CST)
1348 register tree type = TREE_TYPE (arg1);
1349 register tree r1 = TREE_REALPART (arg1);
1350 register tree i1 = TREE_IMAGPART (arg1);
1351 register tree r2 = TREE_REALPART (arg2);
1352 register tree i2 = TREE_IMAGPART (arg2);
1358 t = build_complex (type,
1359 const_binop (PLUS_EXPR, r1, r2, notrunc),
1360 const_binop (PLUS_EXPR, i1, i2, notrunc));
1364 t = build_complex (type,
1365 const_binop (MINUS_EXPR, r1, r2, notrunc),
1366 const_binop (MINUS_EXPR, i1, i2, notrunc));
1370 t = build_complex (type,
1371 const_binop (MINUS_EXPR,
1372 const_binop (MULT_EXPR,
1374 const_binop (MULT_EXPR,
1377 const_binop (PLUS_EXPR,
1378 const_binop (MULT_EXPR,
1380 const_binop (MULT_EXPR,
1387 register tree magsquared
1388 = const_binop (PLUS_EXPR,
1389 const_binop (MULT_EXPR, r2, r2, notrunc),
1390 const_binop (MULT_EXPR, i2, i2, notrunc),
1393 t = build_complex (type,
1395 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1396 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1397 const_binop (PLUS_EXPR,
1398 const_binop (MULT_EXPR, r1, r2,
1400 const_binop (MULT_EXPR, i1, i2,
1403 magsquared, notrunc),
1405 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1406 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1407 const_binop (MINUS_EXPR,
1408 const_binop (MULT_EXPR, i1, r2,
1410 const_binop (MULT_EXPR, r1, i2,
1413 magsquared, notrunc));
1425 /* Return an INTEGER_CST with value V . The type is determined by bit_p:
1426 if it is zero, the type is taken from sizetype; if it is one, the type
1427 is taken from bitsizetype. */
1430 size_int_wide (number, high, bit_p)
1431 unsigned HOST_WIDE_INT number, high;
1435 /* Type-size nodes already made for small sizes. */
1436 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1][2];
1438 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high
1439 && size_table[number][bit_p] != 0)
1440 return size_table[number][bit_p];
1441 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high)
1443 push_obstacks_nochange ();
1444 /* Make this a permanent node. */
1445 end_temporary_allocation ();
1446 t = build_int_2 (number, 0);
1447 TREE_TYPE (t) = sizetype_tab[bit_p];
1448 size_table[number][bit_p] = t;
1453 t = build_int_2 (number, high);
1454 TREE_TYPE (t) = sizetype_tab[bit_p];
1455 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1460 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1461 CODE is a tree code. Data type is taken from `sizetype',
1462 If the operands are constant, so is the result. */
1465 size_binop (code, arg0, arg1)
1466 enum tree_code code;
1469 /* Handle the special case of two integer constants faster. */
1470 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1472 /* And some specific cases even faster than that. */
1473 if (code == PLUS_EXPR && integer_zerop (arg0))
1475 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1476 && integer_zerop (arg1))
1478 else if (code == MULT_EXPR && integer_onep (arg0))
1481 /* Handle general case of two integer constants. */
1482 return int_const_binop (code, arg0, arg1, 0, 1);
1485 if (arg0 == error_mark_node || arg1 == error_mark_node)
1486 return error_mark_node;
1488 return fold (build (code, sizetype, arg0, arg1));
1491 /* Given T, a tree representing type conversion of ARG1, a constant,
1492 return a constant tree representing the result of conversion. */
1495 fold_convert (t, arg1)
1499 register tree type = TREE_TYPE (t);
1502 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1504 if (TREE_CODE (arg1) == INTEGER_CST)
1506 /* If we would build a constant wider than GCC supports,
1507 leave the conversion unfolded. */
1508 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1511 /* Given an integer constant, make new constant with new type,
1512 appropriately sign-extended or truncated. */
1513 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1514 TREE_INT_CST_HIGH (arg1));
1515 TREE_TYPE (t) = type;
1516 /* Indicate an overflow if (1) ARG1 already overflowed,
1517 or (2) force_fit_type indicates an overflow.
1518 Tell force_fit_type that an overflow has already occurred
1519 if ARG1 is a too-large unsigned value and T is signed.
1520 But don't indicate an overflow if converting a pointer. */
1522 = (TREE_OVERFLOW (arg1)
1523 || (force_fit_type (t,
1524 (TREE_INT_CST_HIGH (arg1) < 0
1525 && (TREE_UNSIGNED (type)
1526 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1527 && TREE_CODE (TREE_TYPE (arg1)) != POINTER_TYPE));
1528 TREE_CONSTANT_OVERFLOW (t)
1529 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1531 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1532 else if (TREE_CODE (arg1) == REAL_CST)
1534 /* Don't initialize these, use assignments.
1535 Initialized local aggregates don't work on old compilers. */
1539 tree type1 = TREE_TYPE (arg1);
1542 x = TREE_REAL_CST (arg1);
1543 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1545 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1546 if (!no_upper_bound)
1547 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1549 /* See if X will be in range after truncation towards 0.
1550 To compensate for truncation, move the bounds away from 0,
1551 but reject if X exactly equals the adjusted bounds. */
1552 #ifdef REAL_ARITHMETIC
1553 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1554 if (!no_upper_bound)
1555 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1558 if (!no_upper_bound)
1561 /* If X is a NaN, use zero instead and show we have an overflow.
1562 Otherwise, range check. */
1563 if (REAL_VALUE_ISNAN (x))
1564 overflow = 1, x = dconst0;
1565 else if (! (REAL_VALUES_LESS (l, x)
1567 && REAL_VALUES_LESS (x, u)))
1570 #ifndef REAL_ARITHMETIC
1572 HOST_WIDE_INT low, high;
1573 HOST_WIDE_INT half_word
1574 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1579 high = (HOST_WIDE_INT) (x / half_word / half_word);
1580 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1581 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1583 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1584 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1587 low = (HOST_WIDE_INT) x;
1588 if (TREE_REAL_CST (arg1) < 0)
1589 neg_double (low, high, &low, &high);
1590 t = build_int_2 (low, high);
1594 HOST_WIDE_INT low, high;
1595 REAL_VALUE_TO_INT (&low, &high, x);
1596 t = build_int_2 (low, high);
1599 TREE_TYPE (t) = type;
1601 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1602 TREE_CONSTANT_OVERFLOW (t)
1603 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1605 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1606 TREE_TYPE (t) = type;
1608 else if (TREE_CODE (type) == REAL_TYPE)
1610 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1611 if (TREE_CODE (arg1) == INTEGER_CST)
1612 return build_real_from_int_cst (type, arg1);
1613 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1614 if (TREE_CODE (arg1) == REAL_CST)
1616 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1619 TREE_TYPE (arg1) = type;
1622 else if (setjmp (float_error))
1625 t = copy_node (arg1);
1628 set_float_handler (float_error);
1630 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1631 TREE_REAL_CST (arg1)));
1632 set_float_handler (NULL_PTR);
1636 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1637 TREE_CONSTANT_OVERFLOW (t)
1638 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1642 TREE_CONSTANT (t) = 1;
1646 /* Return an expr equal to X but certainly not valid as an lvalue.
1647 Also make sure it is not valid as an null pointer constant. */
1655 /* These things are certainly not lvalues. */
1656 if (TREE_CODE (x) == NON_LVALUE_EXPR
1657 || TREE_CODE (x) == INTEGER_CST
1658 || TREE_CODE (x) == REAL_CST
1659 || TREE_CODE (x) == STRING_CST
1660 || TREE_CODE (x) == ADDR_EXPR)
1662 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1664 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1665 so convert_for_assignment won't strip it.
1666 This is so this 0 won't be treated as a null pointer constant. */
1667 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1668 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1674 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1675 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1679 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1680 Zero means allow extended lvalues. */
1682 int pedantic_lvalues;
1684 /* When pedantic, return an expr equal to X but certainly not valid as a
1685 pedantic lvalue. Otherwise, return X. */
1688 pedantic_non_lvalue (x)
1691 if (pedantic_lvalues)
1692 return non_lvalue (x);
1697 /* Given a tree comparison code, return the code that is the logical inverse
1698 of the given code. It is not safe to do this for floating-point
1699 comparisons, except for NE_EXPR and EQ_EXPR. */
1701 static enum tree_code
1702 invert_tree_comparison (code)
1703 enum tree_code code;
1724 /* Similar, but return the comparison that results if the operands are
1725 swapped. This is safe for floating-point. */
1727 static enum tree_code
1728 swap_tree_comparison (code)
1729 enum tree_code code;
1749 /* Return nonzero if CODE is a tree code that represents a truth value. */
1752 truth_value_p (code)
1753 enum tree_code code;
1755 return (TREE_CODE_CLASS (code) == '<'
1756 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1757 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1758 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1761 /* Return nonzero if two operands are necessarily equal.
1762 If ONLY_CONST is non-zero, only return non-zero for constants.
1763 This function tests whether the operands are indistinguishable;
1764 it does not test whether they are equal using C's == operation.
1765 The distinction is important for IEEE floating point, because
1766 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1767 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1770 operand_equal_p (arg0, arg1, only_const)
1774 /* If both types don't have the same signedness, then we can't consider
1775 them equal. We must check this before the STRIP_NOPS calls
1776 because they may change the signedness of the arguments. */
1777 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1783 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1784 /* This is needed for conversions and for COMPONENT_REF.
1785 Might as well play it safe and always test this. */
1786 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1789 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1790 We don't care about side effects in that case because the SAVE_EXPR
1791 takes care of that for us. In all other cases, two expressions are
1792 equal if they have no side effects. If we have two identical
1793 expressions with side effects that should be treated the same due
1794 to the only side effects being identical SAVE_EXPR's, that will
1795 be detected in the recursive calls below. */
1796 if (arg0 == arg1 && ! only_const
1797 && (TREE_CODE (arg0) == SAVE_EXPR
1798 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1801 /* Next handle constant cases, those for which we can return 1 even
1802 if ONLY_CONST is set. */
1803 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1804 switch (TREE_CODE (arg0))
1807 return (! TREE_CONSTANT_OVERFLOW (arg0)
1808 && ! TREE_CONSTANT_OVERFLOW (arg1)
1809 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1810 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
1813 return (! TREE_CONSTANT_OVERFLOW (arg0)
1814 && ! TREE_CONSTANT_OVERFLOW (arg1)
1815 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
1816 TREE_REAL_CST (arg1)));
1819 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1821 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1825 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1826 && ! strncmp (TREE_STRING_POINTER (arg0),
1827 TREE_STRING_POINTER (arg1),
1828 TREE_STRING_LENGTH (arg0)));
1831 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1840 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1843 /* Two conversions are equal only if signedness and modes match. */
1844 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1845 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1846 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1849 return operand_equal_p (TREE_OPERAND (arg0, 0),
1850 TREE_OPERAND (arg1, 0), 0);
1854 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1855 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1859 /* For commutative ops, allow the other order. */
1860 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1861 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1862 || TREE_CODE (arg0) == BIT_IOR_EXPR
1863 || TREE_CODE (arg0) == BIT_XOR_EXPR
1864 || TREE_CODE (arg0) == BIT_AND_EXPR
1865 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1866 && operand_equal_p (TREE_OPERAND (arg0, 0),
1867 TREE_OPERAND (arg1, 1), 0)
1868 && operand_equal_p (TREE_OPERAND (arg0, 1),
1869 TREE_OPERAND (arg1, 0), 0));
1872 switch (TREE_CODE (arg0))
1875 return operand_equal_p (TREE_OPERAND (arg0, 0),
1876 TREE_OPERAND (arg1, 0), 0);
1880 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1881 TREE_OPERAND (arg1, 0), 0)
1882 && operand_equal_p (TREE_OPERAND (arg0, 1),
1883 TREE_OPERAND (arg1, 1), 0));
1886 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1887 TREE_OPERAND (arg1, 0), 0)
1888 && operand_equal_p (TREE_OPERAND (arg0, 1),
1889 TREE_OPERAND (arg1, 1), 0)
1890 && operand_equal_p (TREE_OPERAND (arg0, 2),
1891 TREE_OPERAND (arg1, 2), 0));
1901 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1902 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1904 When in doubt, return 0. */
1907 operand_equal_for_comparison_p (arg0, arg1, other)
1911 int unsignedp1, unsignedpo;
1912 tree primarg1, primother;
1913 unsigned correct_width;
1915 if (operand_equal_p (arg0, arg1, 0))
1918 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1919 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1922 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1923 actual comparison operand, ARG0.
1925 First throw away any conversions to wider types
1926 already present in the operands. */
1928 primarg1 = get_narrower (arg1, &unsignedp1);
1929 primother = get_narrower (other, &unsignedpo);
1931 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1932 if (unsignedp1 == unsignedpo
1933 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1934 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1936 tree type = TREE_TYPE (arg0);
1938 /* Make sure shorter operand is extended the right way
1939 to match the longer operand. */
1940 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1941 TREE_TYPE (primarg1)),
1944 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1951 /* See if ARG is an expression that is either a comparison or is performing
1952 arithmetic on comparisons. The comparisons must only be comparing
1953 two different values, which will be stored in *CVAL1 and *CVAL2; if
1954 they are non-zero it means that some operands have already been found.
1955 No variables may be used anywhere else in the expression except in the
1956 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1957 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1959 If this is true, return 1. Otherwise, return zero. */
1962 twoval_comparison_p (arg, cval1, cval2, save_p)
1964 tree *cval1, *cval2;
1967 enum tree_code code = TREE_CODE (arg);
1968 char class = TREE_CODE_CLASS (code);
1970 /* We can handle some of the 'e' cases here. */
1971 if (class == 'e' && code == TRUTH_NOT_EXPR)
1973 else if (class == 'e'
1974 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1975 || code == COMPOUND_EXPR))
1978 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1979 the expression. There may be no way to make this work, but it needs
1980 to be looked at again for 2.6. */
1982 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1984 /* If we've already found a CVAL1 or CVAL2, this expression is
1985 two complex to handle. */
1986 if (*cval1 || *cval2)
1997 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
2000 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
2001 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2002 cval1, cval2, save_p));
2008 if (code == COND_EXPR)
2009 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2010 cval1, cval2, save_p)
2011 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2012 cval1, cval2, save_p)
2013 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2014 cval1, cval2, save_p));
2018 /* First see if we can handle the first operand, then the second. For
2019 the second operand, we know *CVAL1 can't be zero. It must be that
2020 one side of the comparison is each of the values; test for the
2021 case where this isn't true by failing if the two operands
2024 if (operand_equal_p (TREE_OPERAND (arg, 0),
2025 TREE_OPERAND (arg, 1), 0))
2029 *cval1 = TREE_OPERAND (arg, 0);
2030 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2032 else if (*cval2 == 0)
2033 *cval2 = TREE_OPERAND (arg, 0);
2034 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2039 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2041 else if (*cval2 == 0)
2042 *cval2 = TREE_OPERAND (arg, 1);
2043 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2055 /* ARG is a tree that is known to contain just arithmetic operations and
2056 comparisons. Evaluate the operations in the tree substituting NEW0 for
2057 any occurrence of OLD0 as an operand of a comparison and likewise for
2061 eval_subst (arg, old0, new0, old1, new1)
2063 tree old0, new0, old1, new1;
2065 tree type = TREE_TYPE (arg);
2066 enum tree_code code = TREE_CODE (arg);
2067 char class = TREE_CODE_CLASS (code);
2069 /* We can handle some of the 'e' cases here. */
2070 if (class == 'e' && code == TRUTH_NOT_EXPR)
2072 else if (class == 'e'
2073 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2079 return fold (build1 (code, type,
2080 eval_subst (TREE_OPERAND (arg, 0),
2081 old0, new0, old1, new1)));
2084 return fold (build (code, type,
2085 eval_subst (TREE_OPERAND (arg, 0),
2086 old0, new0, old1, new1),
2087 eval_subst (TREE_OPERAND (arg, 1),
2088 old0, new0, old1, new1)));
2094 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2097 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2100 return fold (build (code, type,
2101 eval_subst (TREE_OPERAND (arg, 0),
2102 old0, new0, old1, new1),
2103 eval_subst (TREE_OPERAND (arg, 1),
2104 old0, new0, old1, new1),
2105 eval_subst (TREE_OPERAND (arg, 2),
2106 old0, new0, old1, new1)));
2110 /* fall through (???) */
2114 tree arg0 = TREE_OPERAND (arg, 0);
2115 tree arg1 = TREE_OPERAND (arg, 1);
2117 /* We need to check both for exact equality and tree equality. The
2118 former will be true if the operand has a side-effect. In that
2119 case, we know the operand occurred exactly once. */
2121 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2123 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2126 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2128 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2131 return fold (build (code, type, arg0, arg1));
2139 /* Return a tree for the case when the result of an expression is RESULT
2140 converted to TYPE and OMITTED was previously an operand of the expression
2141 but is now not needed (e.g., we folded OMITTED * 0).
2143 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2144 the conversion of RESULT to TYPE. */
2147 omit_one_operand (type, result, omitted)
2148 tree type, result, omitted;
2150 tree t = convert (type, result);
2152 if (TREE_SIDE_EFFECTS (omitted))
2153 return build (COMPOUND_EXPR, type, omitted, t);
2155 return non_lvalue (t);
2158 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2161 pedantic_omit_one_operand (type, result, omitted)
2162 tree type, result, omitted;
2164 tree t = convert (type, result);
2166 if (TREE_SIDE_EFFECTS (omitted))
2167 return build (COMPOUND_EXPR, type, omitted, t);
2169 return pedantic_non_lvalue (t);
2174 /* Return a simplified tree node for the truth-negation of ARG. This
2175 never alters ARG itself. We assume that ARG is an operation that
2176 returns a truth value (0 or 1). */
2179 invert_truthvalue (arg)
2182 tree type = TREE_TYPE (arg);
2183 enum tree_code code = TREE_CODE (arg);
2185 if (code == ERROR_MARK)
2188 /* If this is a comparison, we can simply invert it, except for
2189 floating-point non-equality comparisons, in which case we just
2190 enclose a TRUTH_NOT_EXPR around what we have. */
2192 if (TREE_CODE_CLASS (code) == '<')
2194 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2195 && code != NE_EXPR && code != EQ_EXPR)
2196 return build1 (TRUTH_NOT_EXPR, type, arg);
2198 return build (invert_tree_comparison (code), type,
2199 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2205 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2206 && TREE_INT_CST_HIGH (arg) == 0, 0));
2208 case TRUTH_AND_EXPR:
2209 return build (TRUTH_OR_EXPR, type,
2210 invert_truthvalue (TREE_OPERAND (arg, 0)),
2211 invert_truthvalue (TREE_OPERAND (arg, 1)));
2214 return build (TRUTH_AND_EXPR, type,
2215 invert_truthvalue (TREE_OPERAND (arg, 0)),
2216 invert_truthvalue (TREE_OPERAND (arg, 1)));
2218 case TRUTH_XOR_EXPR:
2219 /* Here we can invert either operand. We invert the first operand
2220 unless the second operand is a TRUTH_NOT_EXPR in which case our
2221 result is the XOR of the first operand with the inside of the
2222 negation of the second operand. */
2224 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2225 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2226 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2228 return build (TRUTH_XOR_EXPR, type,
2229 invert_truthvalue (TREE_OPERAND (arg, 0)),
2230 TREE_OPERAND (arg, 1));
2232 case TRUTH_ANDIF_EXPR:
2233 return build (TRUTH_ORIF_EXPR, type,
2234 invert_truthvalue (TREE_OPERAND (arg, 0)),
2235 invert_truthvalue (TREE_OPERAND (arg, 1)));
2237 case TRUTH_ORIF_EXPR:
2238 return build (TRUTH_ANDIF_EXPR, type,
2239 invert_truthvalue (TREE_OPERAND (arg, 0)),
2240 invert_truthvalue (TREE_OPERAND (arg, 1)));
2242 case TRUTH_NOT_EXPR:
2243 return TREE_OPERAND (arg, 0);
2246 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2247 invert_truthvalue (TREE_OPERAND (arg, 1)),
2248 invert_truthvalue (TREE_OPERAND (arg, 2)));
2251 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2252 invert_truthvalue (TREE_OPERAND (arg, 1)));
2254 case NON_LVALUE_EXPR:
2255 return invert_truthvalue (TREE_OPERAND (arg, 0));
2260 return build1 (TREE_CODE (arg), type,
2261 invert_truthvalue (TREE_OPERAND (arg, 0)));
2264 if (!integer_onep (TREE_OPERAND (arg, 1)))
2266 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2269 return build1 (TRUTH_NOT_EXPR, type, arg);
2271 case CLEANUP_POINT_EXPR:
2272 return build1 (CLEANUP_POINT_EXPR, type,
2273 invert_truthvalue (TREE_OPERAND (arg, 0)));
2278 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2280 return build1 (TRUTH_NOT_EXPR, type, arg);
2283 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2284 operands are another bit-wise operation with a common input. If so,
2285 distribute the bit operations to save an operation and possibly two if
2286 constants are involved. For example, convert
2287 (A | B) & (A | C) into A | (B & C)
2288 Further simplification will occur if B and C are constants.
2290 If this optimization cannot be done, 0 will be returned. */
2293 distribute_bit_expr (code, type, arg0, arg1)
2294 enum tree_code code;
2301 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2302 || TREE_CODE (arg0) == code
2303 || (TREE_CODE (arg0) != BIT_AND_EXPR
2304 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2307 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2309 common = TREE_OPERAND (arg0, 0);
2310 left = TREE_OPERAND (arg0, 1);
2311 right = TREE_OPERAND (arg1, 1);
2313 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2315 common = TREE_OPERAND (arg0, 0);
2316 left = TREE_OPERAND (arg0, 1);
2317 right = TREE_OPERAND (arg1, 0);
2319 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2321 common = TREE_OPERAND (arg0, 1);
2322 left = TREE_OPERAND (arg0, 0);
2323 right = TREE_OPERAND (arg1, 1);
2325 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2327 common = TREE_OPERAND (arg0, 1);
2328 left = TREE_OPERAND (arg0, 0);
2329 right = TREE_OPERAND (arg1, 0);
2334 return fold (build (TREE_CODE (arg0), type, common,
2335 fold (build (code, type, left, right))));
2338 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2339 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2342 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2345 int bitsize, bitpos;
2348 tree result = build (BIT_FIELD_REF, type, inner,
2349 size_int (bitsize), bitsize_int (bitpos, 0L));
2351 TREE_UNSIGNED (result) = unsignedp;
2356 /* Optimize a bit-field compare.
2358 There are two cases: First is a compare against a constant and the
2359 second is a comparison of two items where the fields are at the same
2360 bit position relative to the start of a chunk (byte, halfword, word)
2361 large enough to contain it. In these cases we can avoid the shift
2362 implicit in bitfield extractions.
2364 For constants, we emit a compare of the shifted constant with the
2365 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2366 compared. For two fields at the same position, we do the ANDs with the
2367 similar mask and compare the result of the ANDs.
2369 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2370 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2371 are the left and right operands of the comparison, respectively.
2373 If the optimization described above can be done, we return the resulting
2374 tree. Otherwise we return zero. */
2377 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2378 enum tree_code code;
2382 int lbitpos, lbitsize, rbitpos, rbitsize;
2383 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2384 tree type = TREE_TYPE (lhs);
2385 tree signed_type, unsigned_type;
2386 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2387 enum machine_mode lmode, rmode, lnmode, rnmode;
2388 int lunsignedp, runsignedp;
2389 int lvolatilep = 0, rvolatilep = 0;
2391 tree linner, rinner;
2395 /* Get all the information about the extractions being done. If the bit size
2396 if the same as the size of the underlying object, we aren't doing an
2397 extraction at all and so can do nothing. */
2398 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2399 &lunsignedp, &lvolatilep, &alignment);
2400 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2406 /* If this is not a constant, we can only do something if bit positions,
2407 sizes, and signedness are the same. */
2408 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2409 &runsignedp, &rvolatilep, &alignment);
2411 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2412 || lunsignedp != runsignedp || offset != 0)
2416 /* See if we can find a mode to refer to this field. We should be able to,
2417 but fail if we can't. */
2418 lnmode = get_best_mode (lbitsize, lbitpos,
2419 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2421 if (lnmode == VOIDmode)
2424 /* Set signed and unsigned types of the precision of this mode for the
2426 signed_type = type_for_mode (lnmode, 0);
2427 unsigned_type = type_for_mode (lnmode, 1);
2431 rnmode = get_best_mode (rbitsize, rbitpos,
2432 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2434 if (rnmode == VOIDmode)
2438 /* Compute the bit position and size for the new reference and our offset
2439 within it. If the new reference is the same size as the original, we
2440 won't optimize anything, so return zero. */
2441 lnbitsize = GET_MODE_BITSIZE (lnmode);
2442 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2443 lbitpos -= lnbitpos;
2444 if (lnbitsize == lbitsize)
2449 rnbitsize = GET_MODE_BITSIZE (rnmode);
2450 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2451 rbitpos -= rnbitpos;
2452 if (rnbitsize == rbitsize)
2456 if (BYTES_BIG_ENDIAN)
2457 lbitpos = lnbitsize - lbitsize - lbitpos;
2459 /* Make the mask to be used against the extracted field. */
2460 mask = build_int_2 (~0, ~0);
2461 TREE_TYPE (mask) = unsigned_type;
2462 force_fit_type (mask, 0);
2463 mask = convert (unsigned_type, mask);
2464 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2465 mask = const_binop (RSHIFT_EXPR, mask,
2466 size_int (lnbitsize - lbitsize - lbitpos), 0);
2469 /* If not comparing with constant, just rework the comparison
2471 return build (code, compare_type,
2472 build (BIT_AND_EXPR, unsigned_type,
2473 make_bit_field_ref (linner, unsigned_type,
2474 lnbitsize, lnbitpos, 1),
2476 build (BIT_AND_EXPR, unsigned_type,
2477 make_bit_field_ref (rinner, unsigned_type,
2478 rnbitsize, rnbitpos, 1),
2481 /* Otherwise, we are handling the constant case. See if the constant is too
2482 big for the field. Warn and return a tree of for 0 (false) if so. We do
2483 this not only for its own sake, but to avoid having to test for this
2484 error case below. If we didn't, we might generate wrong code.
2486 For unsigned fields, the constant shifted right by the field length should
2487 be all zero. For signed fields, the high-order bits should agree with
2492 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2493 convert (unsigned_type, rhs),
2494 size_int (lbitsize), 0)))
2496 warning ("comparison is always %s due to width of bitfield",
2497 code == NE_EXPR ? "one" : "zero");
2498 return convert (compare_type,
2500 ? integer_one_node : integer_zero_node));
2505 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2506 size_int (lbitsize - 1), 0);
2507 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2509 warning ("comparison is always %s due to width of bitfield",
2510 code == NE_EXPR ? "one" : "zero");
2511 return convert (compare_type,
2513 ? integer_one_node : integer_zero_node));
2517 /* Single-bit compares should always be against zero. */
2518 if (lbitsize == 1 && ! integer_zerop (rhs))
2520 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2521 rhs = convert (type, integer_zero_node);
2524 /* Make a new bitfield reference, shift the constant over the
2525 appropriate number of bits and mask it with the computed mask
2526 (in case this was a signed field). If we changed it, make a new one. */
2527 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2530 TREE_SIDE_EFFECTS (lhs) = 1;
2531 TREE_THIS_VOLATILE (lhs) = 1;
2534 rhs = fold (const_binop (BIT_AND_EXPR,
2535 const_binop (LSHIFT_EXPR,
2536 convert (unsigned_type, rhs),
2537 size_int (lbitpos), 0),
2540 return build (code, compare_type,
2541 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2545 /* Subroutine for fold_truthop: decode a field reference.
2547 If EXP is a comparison reference, we return the innermost reference.
2549 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2550 set to the starting bit number.
2552 If the innermost field can be completely contained in a mode-sized
2553 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2555 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2556 otherwise it is not changed.
2558 *PUNSIGNEDP is set to the signedness of the field.
2560 *PMASK is set to the mask used. This is either contained in a
2561 BIT_AND_EXPR or derived from the width of the field.
2563 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2565 Return 0 if this is not a component reference or is one that we can't
2566 do anything with. */
2569 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2570 pvolatilep, pmask, pand_mask)
2572 int *pbitsize, *pbitpos;
2573 enum machine_mode *pmode;
2574 int *punsignedp, *pvolatilep;
2579 tree mask, inner, offset;
2584 /* All the optimizations using this function assume integer fields.
2585 There are problems with FP fields since the type_for_size call
2586 below can fail for, e.g., XFmode. */
2587 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2592 if (TREE_CODE (exp) == BIT_AND_EXPR)
2594 and_mask = TREE_OPERAND (exp, 1);
2595 exp = TREE_OPERAND (exp, 0);
2596 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2597 if (TREE_CODE (and_mask) != INTEGER_CST)
2602 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2603 punsignedp, pvolatilep, &alignment);
2604 if ((inner == exp && and_mask == 0)
2605 || *pbitsize < 0 || offset != 0)
2608 /* Compute the mask to access the bitfield. */
2609 unsigned_type = type_for_size (*pbitsize, 1);
2610 precision = TYPE_PRECISION (unsigned_type);
2612 mask = build_int_2 (~0, ~0);
2613 TREE_TYPE (mask) = unsigned_type;
2614 force_fit_type (mask, 0);
2615 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2616 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2618 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2620 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2621 convert (unsigned_type, and_mask), mask));
2624 *pand_mask = and_mask;
2628 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2632 all_ones_mask_p (mask, size)
2636 tree type = TREE_TYPE (mask);
2637 int precision = TYPE_PRECISION (type);
2640 tmask = build_int_2 (~0, ~0);
2641 TREE_TYPE (tmask) = signed_type (type);
2642 force_fit_type (tmask, 0);
2644 tree_int_cst_equal (mask,
2645 const_binop (RSHIFT_EXPR,
2646 const_binop (LSHIFT_EXPR, tmask,
2647 size_int (precision - size),
2649 size_int (precision - size), 0));
2652 /* Subroutine for fold_truthop: determine if an operand is simple enough
2653 to be evaluated unconditionally. */
2656 simple_operand_p (exp)
2659 /* Strip any conversions that don't change the machine mode. */
2660 while ((TREE_CODE (exp) == NOP_EXPR
2661 || TREE_CODE (exp) == CONVERT_EXPR)
2662 && (TYPE_MODE (TREE_TYPE (exp))
2663 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2664 exp = TREE_OPERAND (exp, 0);
2666 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2667 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2668 && ! TREE_ADDRESSABLE (exp)
2669 && ! TREE_THIS_VOLATILE (exp)
2670 && ! DECL_NONLOCAL (exp)
2671 /* Don't regard global variables as simple. They may be
2672 allocated in ways unknown to the compiler (shared memory,
2673 #pragma weak, etc). */
2674 && ! TREE_PUBLIC (exp)
2675 && ! DECL_EXTERNAL (exp)
2676 /* Loading a static variable is unduly expensive, but global
2677 registers aren't expensive. */
2678 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2681 /* The following functions are subroutines to fold_range_test and allow it to
2682 try to change a logical combination of comparisons into a range test.
2685 X == 2 && X == 3 && X == 4 && X == 5
2689 (unsigned) (X - 2) <= 3
2691 We describe each set of comparisons as being either inside or outside
2692 a range, using a variable named like IN_P, and then describe the
2693 range with a lower and upper bound. If one of the bounds is omitted,
2694 it represents either the highest or lowest value of the type.
2696 In the comments below, we represent a range by two numbers in brackets
2697 preceded by a "+" to designate being inside that range, or a "-" to
2698 designate being outside that range, so the condition can be inverted by
2699 flipping the prefix. An omitted bound is represented by a "-". For
2700 example, "- [-, 10]" means being outside the range starting at the lowest
2701 possible value and ending at 10, in other words, being greater than 10.
2702 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2705 We set up things so that the missing bounds are handled in a consistent
2706 manner so neither a missing bound nor "true" and "false" need to be
2707 handled using a special case. */
2709 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2710 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2711 and UPPER1_P are nonzero if the respective argument is an upper bound
2712 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2713 must be specified for a comparison. ARG1 will be converted to ARG0's
2714 type if both are specified. */
2717 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2718 enum tree_code code;
2721 int upper0_p, upper1_p;
2727 /* If neither arg represents infinity, do the normal operation.
2728 Else, if not a comparison, return infinity. Else handle the special
2729 comparison rules. Note that most of the cases below won't occur, but
2730 are handled for consistency. */
2732 if (arg0 != 0 && arg1 != 0)
2734 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2735 arg0, convert (TREE_TYPE (arg0), arg1)));
2737 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2740 if (TREE_CODE_CLASS (code) != '<')
2743 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2744 for neither. Then compute our result treating them as never equal
2745 and comparing bounds to non-bounds as above. */
2746 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2747 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2750 case EQ_EXPR: case NE_EXPR:
2751 result = (code == NE_EXPR);
2753 case LT_EXPR: case LE_EXPR:
2754 result = sgn0 < sgn1;
2756 case GT_EXPR: case GE_EXPR:
2757 result = sgn0 > sgn1;
2763 return convert (type, result ? integer_one_node : integer_zero_node);
2766 /* Given EXP, a logical expression, set the range it is testing into
2767 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2768 actually being tested. *PLOW and *PHIGH will have be made the same type
2769 as the returned expression. If EXP is not a comparison, we will most
2770 likely not be returning a useful value and range. */
2773 make_range (exp, pin_p, plow, phigh)
2778 enum tree_code code;
2779 tree arg0, arg1, type;
2781 tree low, high, n_low, n_high;
2783 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2784 and see if we can refine the range. Some of the cases below may not
2785 happen, but it doesn't seem worth worrying about this. We "continue"
2786 the outer loop when we've changed something; otherwise we "break"
2787 the switch, which will "break" the while. */
2789 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2793 code = TREE_CODE (exp);
2794 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2795 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2796 || TREE_CODE_CLASS (code) == '2')
2797 type = TREE_TYPE (arg0);
2801 case TRUTH_NOT_EXPR:
2802 in_p = ! in_p, exp = arg0;
2805 case EQ_EXPR: case NE_EXPR:
2806 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2807 /* We can only do something if the range is testing for zero
2808 and if the second operand is an integer constant. Note that
2809 saying something is "in" the range we make is done by
2810 complementing IN_P since it will set in the initial case of
2811 being not equal to zero; "out" is leaving it alone. */
2812 if (low == 0 || high == 0
2813 || ! integer_zerop (low) || ! integer_zerop (high)
2814 || TREE_CODE (arg1) != INTEGER_CST)
2819 case NE_EXPR: /* - [c, c] */
2822 case EQ_EXPR: /* + [c, c] */
2823 in_p = ! in_p, low = high = arg1;
2825 case GT_EXPR: /* - [-, c] */
2826 low = 0, high = arg1;
2828 case GE_EXPR: /* + [c, -] */
2829 in_p = ! in_p, low = arg1, high = 0;
2831 case LT_EXPR: /* - [c, -] */
2832 low = arg1, high = 0;
2834 case LE_EXPR: /* + [-, c] */
2835 in_p = ! in_p, low = 0, high = arg1;
2843 /* If this is an unsigned comparison, we also know that EXP is
2844 greater than or equal to zero. We base the range tests we make
2845 on that fact, so we record it here so we can parse existing
2847 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2849 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2850 1, convert (type, integer_zero_node),
2854 in_p = n_in_p, low = n_low, high = n_high;
2856 /* If the high bound is missing, reverse the range so it
2857 goes from zero to the low bound minus 1. */
2861 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2862 integer_one_node, 0);
2863 low = convert (type, integer_zero_node);
2869 /* (-x) IN [a,b] -> x in [-b, -a] */
2870 n_low = range_binop (MINUS_EXPR, type,
2871 convert (type, integer_zero_node), 0, high, 1);
2872 n_high = range_binop (MINUS_EXPR, type,
2873 convert (type, integer_zero_node), 0, low, 0);
2874 low = n_low, high = n_high;
2880 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2881 convert (type, integer_one_node));
2884 case PLUS_EXPR: case MINUS_EXPR:
2885 if (TREE_CODE (arg1) != INTEGER_CST)
2888 /* If EXP is signed, any overflow in the computation is undefined,
2889 so we don't worry about it so long as our computations on
2890 the bounds don't overflow. For unsigned, overflow is defined
2891 and this is exactly the right thing. */
2892 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2893 type, low, 0, arg1, 0);
2894 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2895 type, high, 1, arg1, 0);
2896 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2897 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2900 /* Check for an unsigned range which has wrapped around the maximum
2901 value thus making n_high < n_low, and normalize it. */
2902 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2904 low = range_binop (PLUS_EXPR, type, n_high, 0,
2905 integer_one_node, 0);
2906 high = range_binop (MINUS_EXPR, type, n_low, 0,
2907 integer_one_node, 0);
2911 low = n_low, high = n_high;
2916 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2917 if (! INTEGRAL_TYPE_P (type)
2918 || (low != 0 && ! int_fits_type_p (low, type))
2919 || (high != 0 && ! int_fits_type_p (high, type)))
2922 n_low = low, n_high = high;
2925 n_low = convert (type, n_low);
2928 n_high = convert (type, n_high);
2930 /* If we're converting from an unsigned to a signed type,
2931 we will be doing the comparison as unsigned. The tests above
2932 have already verified that LOW and HIGH are both positive.
2934 So we have to make sure that the original unsigned value will
2935 be interpreted as positive. */
2936 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
2938 tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
2941 /* A range without an upper bound is, naturally, unbounded.
2942 Since convert would have cropped a very large value, use
2943 the max value for the destination type. */
2945 high_positive = TYPE_MAX_VALUE (equiv_type);
2948 high_positive = TYPE_MAX_VALUE (type);
2952 high_positive = fold (build (RSHIFT_EXPR, type,
2953 convert (type, high_positive),
2954 convert (type, integer_one_node)));
2956 /* If the low bound is specified, "and" the range with the
2957 range for which the original unsigned value will be
2961 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2963 1, convert (type, integer_zero_node),
2967 in_p = (n_in_p == in_p);
2971 /* Otherwise, "or" the range with the range of the input
2972 that will be interpreted as negative. */
2973 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2975 1, convert (type, integer_zero_node),
2979 in_p = (in_p != n_in_p);
2984 low = n_low, high = n_high;
2994 /* If EXP is a constant, we can evaluate whether this is true or false. */
2995 if (TREE_CODE (exp) == INTEGER_CST)
2997 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2999 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3005 *pin_p = in_p, *plow = low, *phigh = high;
3009 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3010 type, TYPE, return an expression to test if EXP is in (or out of, depending
3011 on IN_P) the range. */
3014 build_range_check (type, exp, in_p, low, high)
3020 tree etype = TREE_TYPE (exp);
3024 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3025 return invert_truthvalue (value);
3027 else if (low == 0 && high == 0)
3028 return convert (type, integer_one_node);
3031 return fold (build (LE_EXPR, type, exp, high));
3034 return fold (build (GE_EXPR, type, exp, low));
3036 else if (operand_equal_p (low, high, 0))
3037 return fold (build (EQ_EXPR, type, exp, low));
3039 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
3040 return build_range_check (type, exp, 1, 0, high);
3042 else if (integer_zerop (low))
3044 utype = unsigned_type (etype);
3045 return build_range_check (type, convert (utype, exp), 1, 0,
3046 convert (utype, high));
3049 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3050 && ! TREE_OVERFLOW (value))
3051 return build_range_check (type,
3052 fold (build (MINUS_EXPR, etype, exp, low)),
3053 1, convert (etype, integer_zero_node), value);
3058 /* Given two ranges, see if we can merge them into one. Return 1 if we
3059 can, 0 if we can't. Set the output range into the specified parameters. */
3062 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3066 tree low0, high0, low1, high1;
3074 int lowequal = ((low0 == 0 && low1 == 0)
3075 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3076 low0, 0, low1, 0)));
3077 int highequal = ((high0 == 0 && high1 == 0)
3078 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3079 high0, 1, high1, 1)));
3081 /* Make range 0 be the range that starts first, or ends last if they
3082 start at the same value. Swap them if it isn't. */
3083 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3086 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3087 high1, 1, high0, 1))))
3089 temp = in0_p, in0_p = in1_p, in1_p = temp;
3090 tem = low0, low0 = low1, low1 = tem;
3091 tem = high0, high0 = high1, high1 = tem;
3094 /* Now flag two cases, whether the ranges are disjoint or whether the
3095 second range is totally subsumed in the first. Note that the tests
3096 below are simplified by the ones above. */
3097 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3098 high0, 1, low1, 0));
3099 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3100 high1, 1, high0, 1));
3102 /* We now have four cases, depending on whether we are including or
3103 excluding the two ranges. */
3106 /* If they don't overlap, the result is false. If the second range
3107 is a subset it is the result. Otherwise, the range is from the start
3108 of the second to the end of the first. */
3110 in_p = 0, low = high = 0;
3112 in_p = 1, low = low1, high = high1;
3114 in_p = 1, low = low1, high = high0;
3117 else if (in0_p && ! in1_p)
3119 /* If they don't overlap, the result is the first range. If they are
3120 equal, the result is false. If the second range is a subset of the
3121 first, and the ranges begin at the same place, we go from just after
3122 the end of the first range to the end of the second. If the second
3123 range is not a subset of the first, or if it is a subset and both
3124 ranges end at the same place, the range starts at the start of the
3125 first range and ends just before the second range.
3126 Otherwise, we can't describe this as a single range. */
3128 in_p = 1, low = low0, high = high0;
3129 else if (lowequal && highequal)
3130 in_p = 0, low = high = 0;
3131 else if (subset && lowequal)
3133 in_p = 1, high = high0;
3134 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3135 integer_one_node, 0);
3137 else if (! subset || highequal)
3139 in_p = 1, low = low0;
3140 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3141 integer_one_node, 0);
3147 else if (! in0_p && in1_p)
3149 /* If they don't overlap, the result is the second range. If the second
3150 is a subset of the first, the result is false. Otherwise,
3151 the range starts just after the first range and ends at the
3152 end of the second. */
3154 in_p = 1, low = low1, high = high1;
3156 in_p = 0, low = high = 0;
3159 in_p = 1, high = high1;
3160 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3161 integer_one_node, 0);
3167 /* The case where we are excluding both ranges. Here the complex case
3168 is if they don't overlap. In that case, the only time we have a
3169 range is if they are adjacent. If the second is a subset of the
3170 first, the result is the first. Otherwise, the range to exclude
3171 starts at the beginning of the first range and ends at the end of the
3175 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3176 range_binop (PLUS_EXPR, NULL_TREE,
3178 integer_one_node, 1),
3180 in_p = 0, low = low0, high = high1;
3185 in_p = 0, low = low0, high = high0;
3187 in_p = 0, low = low0, high = high1;
3190 *pin_p = in_p, *plow = low, *phigh = high;
3194 /* EXP is some logical combination of boolean tests. See if we can
3195 merge it into some range test. Return the new tree if so. */
3198 fold_range_test (exp)
3201 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3202 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3203 int in0_p, in1_p, in_p;
3204 tree low0, low1, low, high0, high1, high;
3205 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3206 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3209 /* If this is an OR operation, invert both sides; we will invert
3210 again at the end. */
3212 in0_p = ! in0_p, in1_p = ! in1_p;
3214 /* If both expressions are the same, if we can merge the ranges, and we
3215 can build the range test, return it or it inverted. If one of the
3216 ranges is always true or always false, consider it to be the same
3217 expression as the other. */
3218 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3219 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3221 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3223 : rhs != 0 ? rhs : integer_zero_node,
3225 return or_op ? invert_truthvalue (tem) : tem;
3227 /* On machines where the branch cost is expensive, if this is a
3228 short-circuited branch and the underlying object on both sides
3229 is the same, make a non-short-circuit operation. */
3230 else if (BRANCH_COST >= 2
3231 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3232 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3233 && operand_equal_p (lhs, rhs, 0))
3235 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3236 unless we are at top level, in which case we can't do this. */
3237 if (simple_operand_p (lhs))
3238 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3239 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3240 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3241 TREE_OPERAND (exp, 1));
3243 else if (current_function_decl != 0)
3245 tree common = save_expr (lhs);
3247 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3248 or_op ? ! in0_p : in0_p,
3250 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3251 or_op ? ! in1_p : in1_p,
3253 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3254 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3255 TREE_TYPE (exp), lhs, rhs);
3262 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3263 bit value. Arrange things so the extra bits will be set to zero if and
3264 only if C is signed-extended to its full width. If MASK is nonzero,
3265 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3268 unextend (c, p, unsignedp, mask)
3274 tree type = TREE_TYPE (c);
3275 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3278 if (p == modesize || unsignedp)
3281 /* We work by getting just the sign bit into the low-order bit, then
3282 into the high-order bit, then sign-extend. We then XOR that value
3284 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3285 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3287 /* We must use a signed type in order to get an arithmetic right shift.
3288 However, we must also avoid introducing accidental overflows, so that
3289 a subsequent call to integer_zerop will work. Hence we must
3290 do the type conversion here. At this point, the constant is either
3291 zero or one, and the conversion to a signed type can never overflow.
3292 We could get an overflow if this conversion is done anywhere else. */
3293 if (TREE_UNSIGNED (type))
3294 temp = convert (signed_type (type), temp);
3296 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3297 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3299 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3300 /* If necessary, convert the type back to match the type of C. */
3301 if (TREE_UNSIGNED (type))
3302 temp = convert (type, temp);
3304 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3307 /* Find ways of folding logical expressions of LHS and RHS:
3308 Try to merge two comparisons to the same innermost item.
3309 Look for range tests like "ch >= '0' && ch <= '9'".
3310 Look for combinations of simple terms on machines with expensive branches
3311 and evaluate the RHS unconditionally.
3313 For example, if we have p->a == 2 && p->b == 4 and we can make an
3314 object large enough to span both A and B, we can do this with a comparison
3315 against the object ANDed with the a mask.
3317 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3318 operations to do this with one comparison.
3320 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3321 function and the one above.
3323 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3324 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3326 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3329 We return the simplified tree or 0 if no optimization is possible. */
3332 fold_truthop (code, truth_type, lhs, rhs)
3333 enum tree_code code;
3334 tree truth_type, lhs, rhs;
3336 /* If this is the "or" of two comparisons, we can do something if we
3337 the comparisons are NE_EXPR. If this is the "and", we can do something
3338 if the comparisons are EQ_EXPR. I.e.,
3339 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3341 WANTED_CODE is this operation code. For single bit fields, we can
3342 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3343 comparison for one-bit fields. */
3345 enum tree_code wanted_code;
3346 enum tree_code lcode, rcode;
3347 tree ll_arg, lr_arg, rl_arg, rr_arg;
3348 tree ll_inner, lr_inner, rl_inner, rr_inner;
3349 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3350 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3351 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3352 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3353 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3354 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3355 enum machine_mode lnmode, rnmode;
3356 tree ll_mask, lr_mask, rl_mask, rr_mask;
3357 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3358 tree l_const, r_const;
3360 int first_bit, end_bit;
3363 /* Start by getting the comparison codes. Fail if anything is volatile.
3364 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3365 it were surrounded with a NE_EXPR. */
3367 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3370 lcode = TREE_CODE (lhs);
3371 rcode = TREE_CODE (rhs);
3373 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3374 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3376 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3377 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3379 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3382 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3383 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3385 ll_arg = TREE_OPERAND (lhs, 0);
3386 lr_arg = TREE_OPERAND (lhs, 1);
3387 rl_arg = TREE_OPERAND (rhs, 0);
3388 rr_arg = TREE_OPERAND (rhs, 1);
3390 /* If the RHS can be evaluated unconditionally and its operands are
3391 simple, it wins to evaluate the RHS unconditionally on machines
3392 with expensive branches. In this case, this isn't a comparison
3393 that can be merged. */
3395 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3396 are with zero (tmw). */
3398 if (BRANCH_COST >= 2
3399 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3400 && simple_operand_p (rl_arg)
3401 && simple_operand_p (rr_arg))
3402 return build (code, truth_type, lhs, rhs);
3404 /* See if the comparisons can be merged. Then get all the parameters for
3407 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3408 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3412 ll_inner = decode_field_reference (ll_arg,
3413 &ll_bitsize, &ll_bitpos, &ll_mode,
3414 &ll_unsignedp, &volatilep, &ll_mask,
3416 lr_inner = decode_field_reference (lr_arg,
3417 &lr_bitsize, &lr_bitpos, &lr_mode,
3418 &lr_unsignedp, &volatilep, &lr_mask,
3420 rl_inner = decode_field_reference (rl_arg,
3421 &rl_bitsize, &rl_bitpos, &rl_mode,
3422 &rl_unsignedp, &volatilep, &rl_mask,
3424 rr_inner = decode_field_reference (rr_arg,
3425 &rr_bitsize, &rr_bitpos, &rr_mode,
3426 &rr_unsignedp, &volatilep, &rr_mask,
3429 /* It must be true that the inner operation on the lhs of each
3430 comparison must be the same if we are to be able to do anything.
3431 Then see if we have constants. If not, the same must be true for
3433 if (volatilep || ll_inner == 0 || rl_inner == 0
3434 || ! operand_equal_p (ll_inner, rl_inner, 0))
3437 if (TREE_CODE (lr_arg) == INTEGER_CST
3438 && TREE_CODE (rr_arg) == INTEGER_CST)
3439 l_const = lr_arg, r_const = rr_arg;
3440 else if (lr_inner == 0 || rr_inner == 0
3441 || ! operand_equal_p (lr_inner, rr_inner, 0))
3444 l_const = r_const = 0;
3446 /* If either comparison code is not correct for our logical operation,
3447 fail. However, we can convert a one-bit comparison against zero into
3448 the opposite comparison against that bit being set in the field. */
3450 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3451 if (lcode != wanted_code)
3453 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3455 if (ll_unsignedp || tree_log2 (ll_mask) + 1 < ll_bitsize)
3458 /* Since ll_arg is a single bit bit mask, we can sign extend
3459 it appropriately with a NEGATE_EXPR.
3460 l_const is made a signed value here, but since for l_const != NULL
3461 lr_unsignedp is not used, we don't need to clear the latter. */
3462 l_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (ll_arg),
3463 convert (TREE_TYPE (ll_arg), ll_mask)));
3469 if (rcode != wanted_code)
3471 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3473 if (rl_unsignedp || tree_log2 (rl_mask) + 1 < rl_bitsize)
3476 /* This is analogous to the code for l_const above. */
3477 r_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (rl_arg),
3478 convert (TREE_TYPE (rl_arg), rl_mask)));
3484 /* See if we can find a mode that contains both fields being compared on
3485 the left. If we can't, fail. Otherwise, update all constants and masks
3486 to be relative to a field of that size. */
3487 first_bit = MIN (ll_bitpos, rl_bitpos);
3488 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3489 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3490 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3492 if (lnmode == VOIDmode)
3495 lnbitsize = GET_MODE_BITSIZE (lnmode);
3496 lnbitpos = first_bit & ~ (lnbitsize - 1);
3497 type = type_for_size (lnbitsize, 1);
3498 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3500 if (BYTES_BIG_ENDIAN)
3502 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3503 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3506 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3507 size_int (xll_bitpos), 0);
3508 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3509 size_int (xrl_bitpos), 0);
3513 l_const = convert (type, l_const);
3514 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3515 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3516 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3517 fold (build1 (BIT_NOT_EXPR,
3521 warning ("comparison is always %s",
3522 wanted_code == NE_EXPR ? "one" : "zero");
3524 return convert (truth_type,
3525 wanted_code == NE_EXPR
3526 ? integer_one_node : integer_zero_node);
3531 r_const = convert (type, r_const);
3532 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3533 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3534 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3535 fold (build1 (BIT_NOT_EXPR,
3539 warning ("comparison is always %s",
3540 wanted_code == NE_EXPR ? "one" : "zero");
3542 return convert (truth_type,
3543 wanted_code == NE_EXPR
3544 ? integer_one_node : integer_zero_node);
3548 /* If the right sides are not constant, do the same for it. Also,
3549 disallow this optimization if a size or signedness mismatch occurs
3550 between the left and right sides. */
3553 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3554 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3555 /* Make sure the two fields on the right
3556 correspond to the left without being swapped. */
3557 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3560 first_bit = MIN (lr_bitpos, rr_bitpos);
3561 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3562 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3563 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3565 if (rnmode == VOIDmode)
3568 rnbitsize = GET_MODE_BITSIZE (rnmode);
3569 rnbitpos = first_bit & ~ (rnbitsize - 1);
3570 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3572 if (BYTES_BIG_ENDIAN)
3574 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3575 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3578 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3579 size_int (xlr_bitpos), 0);
3580 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3581 size_int (xrr_bitpos), 0);
3583 /* Make a mask that corresponds to both fields being compared.
3584 Do this for both items being compared. If the masks agree,
3585 we can do this by masking both and comparing the masked
3587 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3588 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3589 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3591 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3592 ll_unsignedp || rl_unsignedp);
3593 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3594 lr_unsignedp || rr_unsignedp);
3595 if (! all_ones_mask_p (ll_mask, lnbitsize))
3597 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3598 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3600 return build (wanted_code, truth_type, lhs, rhs);
3603 /* There is still another way we can do something: If both pairs of
3604 fields being compared are adjacent, we may be able to make a wider
3605 field containing them both. */
3606 if ((ll_bitsize + ll_bitpos == rl_bitpos
3607 && lr_bitsize + lr_bitpos == rr_bitpos)
3608 || (ll_bitpos == rl_bitpos + rl_bitsize
3609 && lr_bitpos == rr_bitpos + rr_bitsize))
3610 return build (wanted_code, truth_type,
3611 make_bit_field_ref (ll_inner, type,
3612 ll_bitsize + rl_bitsize,
3613 MIN (ll_bitpos, rl_bitpos),
3615 make_bit_field_ref (lr_inner, type,
3616 lr_bitsize + rr_bitsize,
3617 MIN (lr_bitpos, rr_bitpos),
3623 /* Handle the case of comparisons with constants. If there is something in
3624 common between the masks, those bits of the constants must be the same.
3625 If not, the condition is always false. Test for this to avoid generating
3626 incorrect code below. */
3627 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3628 if (! integer_zerop (result)
3629 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3630 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3632 if (wanted_code == NE_EXPR)
3634 warning ("`or' of unmatched not-equal tests is always 1");
3635 return convert (truth_type, integer_one_node);
3639 warning ("`and' of mutually exclusive equal-tests is always zero");
3640 return convert (truth_type, integer_zero_node);
3644 /* Construct the expression we will return. First get the component
3645 reference we will make. Unless the mask is all ones the width of
3646 that field, perform the mask operation. Then compare with the
3648 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3649 ll_unsignedp || rl_unsignedp);
3651 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3652 if (! all_ones_mask_p (ll_mask, lnbitsize))
3653 result = build (BIT_AND_EXPR, type, result, ll_mask);
3655 return build (wanted_code, truth_type, result,
3656 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3659 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3660 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3661 that we may sometimes modify the tree. */
3664 strip_compound_expr (t, s)
3668 enum tree_code code = TREE_CODE (t);
3670 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3671 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3672 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3673 return TREE_OPERAND (t, 1);
3675 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3676 don't bother handling any other types. */
3677 else if (code == COND_EXPR)
3679 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3680 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3681 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3683 else if (TREE_CODE_CLASS (code) == '1')
3684 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3685 else if (TREE_CODE_CLASS (code) == '<'
3686 || TREE_CODE_CLASS (code) == '2')
3688 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3689 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3695 /* Perform constant folding and related simplification of EXPR.
3696 The related simplifications include x*1 => x, x*0 => 0, etc.,
3697 and application of the associative law.
3698 NOP_EXPR conversions may be removed freely (as long as we
3699 are careful not to change the C type of the overall expression)
3700 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3701 but we can constant-fold them if they have constant operands. */
3707 register tree t = expr;
3708 tree t1 = NULL_TREE;
3710 tree type = TREE_TYPE (expr);
3711 register tree arg0, arg1;
3712 register enum tree_code code = TREE_CODE (t);
3716 /* WINS will be nonzero when the switch is done
3717 if all operands are constant. */
3721 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3722 Likewise for a SAVE_EXPR that's already been evaluated. */
3723 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3726 /* Return right away if already constant. */
3727 if (TREE_CONSTANT (t))
3729 if (code == CONST_DECL)
3730 return DECL_INITIAL (t);
3734 kind = TREE_CODE_CLASS (code);
3735 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3739 /* Special case for conversion ops that can have fixed point args. */
3740 arg0 = TREE_OPERAND (t, 0);
3742 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3744 STRIP_TYPE_NOPS (arg0);
3746 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3747 subop = TREE_REALPART (arg0);
3751 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3752 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3753 && TREE_CODE (subop) != REAL_CST
3754 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3756 /* Note that TREE_CONSTANT isn't enough:
3757 static var addresses are constant but we can't
3758 do arithmetic on them. */
3761 else if (kind == 'e' || kind == '<'
3762 || kind == '1' || kind == '2' || kind == 'r')
3764 register int len = tree_code_length[(int) code];
3766 for (i = 0; i < len; i++)
3768 tree op = TREE_OPERAND (t, i);
3772 continue; /* Valid for CALL_EXPR, at least. */
3774 if (kind == '<' || code == RSHIFT_EXPR)
3776 /* Signedness matters here. Perhaps we can refine this
3778 STRIP_TYPE_NOPS (op);
3782 /* Strip any conversions that don't change the mode. */
3786 if (TREE_CODE (op) == COMPLEX_CST)
3787 subop = TREE_REALPART (op);
3791 if (TREE_CODE (subop) != INTEGER_CST
3792 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3793 && TREE_CODE (subop) != REAL_CST
3794 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3796 /* Note that TREE_CONSTANT isn't enough:
3797 static var addresses are constant but we can't
3798 do arithmetic on them. */
3808 /* If this is a commutative operation, and ARG0 is a constant, move it
3809 to ARG1 to reduce the number of tests below. */
3810 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3811 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3812 || code == BIT_AND_EXPR)
3813 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3815 tem = arg0; arg0 = arg1; arg1 = tem;
3817 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3818 TREE_OPERAND (t, 1) = tem;
3821 /* Now WINS is set as described above,
3822 ARG0 is the first operand of EXPR,
3823 and ARG1 is the second operand (if it has more than one operand).
3825 First check for cases where an arithmetic operation is applied to a
3826 compound, conditional, or comparison operation. Push the arithmetic
3827 operation inside the compound or conditional to see if any folding
3828 can then be done. Convert comparison to conditional for this purpose.
3829 The also optimizes non-constant cases that used to be done in
3832 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3833 one of the operands is a comparison and the other is a comparison, a
3834 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3835 code below would make the expression more complex. Change it to a
3836 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3837 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3839 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3840 || code == EQ_EXPR || code == NE_EXPR)
3841 && ((truth_value_p (TREE_CODE (arg0))
3842 && (truth_value_p (TREE_CODE (arg1))
3843 || (TREE_CODE (arg1) == BIT_AND_EXPR
3844 && integer_onep (TREE_OPERAND (arg1, 1)))))
3845 || (truth_value_p (TREE_CODE (arg1))
3846 && (truth_value_p (TREE_CODE (arg0))
3847 || (TREE_CODE (arg0) == BIT_AND_EXPR
3848 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3850 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3851 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3855 if (code == EQ_EXPR)
3856 t = invert_truthvalue (t);
3861 if (TREE_CODE_CLASS (code) == '1')
3863 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3864 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3865 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3866 else if (TREE_CODE (arg0) == COND_EXPR)
3868 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3869 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3870 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3872 /* If this was a conversion, and all we did was to move into
3873 inside the COND_EXPR, bring it back out. But leave it if
3874 it is a conversion from integer to integer and the
3875 result precision is no wider than a word since such a
3876 conversion is cheap and may be optimized away by combine,
3877 while it couldn't if it were outside the COND_EXPR. Then return
3878 so we don't get into an infinite recursion loop taking the
3879 conversion out and then back in. */
3881 if ((code == NOP_EXPR || code == CONVERT_EXPR
3882 || code == NON_LVALUE_EXPR)
3883 && TREE_CODE (t) == COND_EXPR
3884 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3885 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3886 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3887 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3888 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3889 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3890 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3891 t = build1 (code, type,
3893 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3894 TREE_OPERAND (t, 0),
3895 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3896 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3899 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3900 return fold (build (COND_EXPR, type, arg0,
3901 fold (build1 (code, type, integer_one_node)),
3902 fold (build1 (code, type, integer_zero_node))));
3904 else if (TREE_CODE_CLASS (code) == '2'
3905 || TREE_CODE_CLASS (code) == '<')
3907 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3908 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3909 fold (build (code, type,
3910 arg0, TREE_OPERAND (arg1, 1))));
3911 else if ((TREE_CODE (arg1) == COND_EXPR
3912 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3913 && TREE_CODE_CLASS (code) != '<'))
3914 && (! TREE_SIDE_EFFECTS (arg0) || current_function_decl != 0))
3916 tree test, true_value, false_value;
3918 if (TREE_CODE (arg1) == COND_EXPR)
3920 test = TREE_OPERAND (arg1, 0);
3921 true_value = TREE_OPERAND (arg1, 1);
3922 false_value = TREE_OPERAND (arg1, 2);
3926 tree testtype = TREE_TYPE (arg1);
3928 true_value = convert (testtype, integer_one_node);
3929 false_value = convert (testtype, integer_zero_node);
3932 /* If ARG0 is complex we want to make sure we only evaluate
3933 it once. Though this is only required if it is volatile, it
3934 might be more efficient even if it is not. However, if we
3935 succeed in folding one part to a constant, we do not need
3936 to make this SAVE_EXPR. Since we do this optimization
3937 primarily to see if we do end up with constant and this
3938 SAVE_EXPR interferes with later optimizations, suppressing
3939 it when we can is important. */
3941 if (TREE_CODE (arg0) != SAVE_EXPR
3942 && ((TREE_CODE (arg0) != VAR_DECL
3943 && TREE_CODE (arg0) != PARM_DECL)
3944 || TREE_SIDE_EFFECTS (arg0)))
3946 tree lhs = fold (build (code, type, arg0, true_value));
3947 tree rhs = fold (build (code, type, arg0, false_value));
3949 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3950 return fold (build (COND_EXPR, type, test, lhs, rhs));
3952 if (current_function_decl != 0)
3953 arg0 = save_expr (arg0);
3956 test = fold (build (COND_EXPR, type, test,
3957 fold (build (code, type, arg0, true_value)),
3958 fold (build (code, type, arg0, false_value))));
3959 if (TREE_CODE (arg0) == SAVE_EXPR)
3960 return build (COMPOUND_EXPR, type,
3961 convert (void_type_node, arg0),
3962 strip_compound_expr (test, arg0));
3964 return convert (type, test);
3967 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3968 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3969 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3970 else if ((TREE_CODE (arg0) == COND_EXPR
3971 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3972 && TREE_CODE_CLASS (code) != '<'))
3973 && (! TREE_SIDE_EFFECTS (arg1) || current_function_decl != 0))
3975 tree test, true_value, false_value;
3977 if (TREE_CODE (arg0) == COND_EXPR)
3979 test = TREE_OPERAND (arg0, 0);
3980 true_value = TREE_OPERAND (arg0, 1);
3981 false_value = TREE_OPERAND (arg0, 2);
3985 tree testtype = TREE_TYPE (arg0);
3987 true_value = convert (testtype, integer_one_node);
3988 false_value = convert (testtype, integer_zero_node);
3991 if (TREE_CODE (arg1) != SAVE_EXPR
3992 && ((TREE_CODE (arg1) != VAR_DECL
3993 && TREE_CODE (arg1) != PARM_DECL)
3994 || TREE_SIDE_EFFECTS (arg1)))
3996 tree lhs = fold (build (code, type, true_value, arg1));
3997 tree rhs = fold (build (code, type, false_value, arg1));
3999 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
4000 || TREE_CONSTANT (arg1))
4001 return fold (build (COND_EXPR, type, test, lhs, rhs));
4003 if (current_function_decl != 0)
4004 arg1 = save_expr (arg1);
4007 test = fold (build (COND_EXPR, type, test,
4008 fold (build (code, type, true_value, arg1)),
4009 fold (build (code, type, false_value, arg1))));
4010 if (TREE_CODE (arg1) == SAVE_EXPR)
4011 return build (COMPOUND_EXPR, type,
4012 convert (void_type_node, arg1),
4013 strip_compound_expr (test, arg1));
4015 return convert (type, test);
4018 else if (TREE_CODE_CLASS (code) == '<'
4019 && TREE_CODE (arg0) == COMPOUND_EXPR)
4020 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4021 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4022 else if (TREE_CODE_CLASS (code) == '<'
4023 && TREE_CODE (arg1) == COMPOUND_EXPR)
4024 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4025 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4037 return fold (DECL_INITIAL (t));
4042 case FIX_TRUNC_EXPR:
4043 /* Other kinds of FIX are not handled properly by fold_convert. */
4045 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4046 return TREE_OPERAND (t, 0);
4048 /* Handle cases of two conversions in a row. */
4049 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4050 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4052 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4053 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4054 tree final_type = TREE_TYPE (t);
4055 int inside_int = INTEGRAL_TYPE_P (inside_type);
4056 int inside_ptr = POINTER_TYPE_P (inside_type);
4057 int inside_float = FLOAT_TYPE_P (inside_type);
4058 int inside_prec = TYPE_PRECISION (inside_type);
4059 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4060 int inter_int = INTEGRAL_TYPE_P (inter_type);
4061 int inter_ptr = POINTER_TYPE_P (inter_type);
4062 int inter_float = FLOAT_TYPE_P (inter_type);
4063 int inter_prec = TYPE_PRECISION (inter_type);
4064 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4065 int final_int = INTEGRAL_TYPE_P (final_type);
4066 int final_ptr = POINTER_TYPE_P (final_type);
4067 int final_float = FLOAT_TYPE_P (final_type);
4068 int final_prec = TYPE_PRECISION (final_type);
4069 int final_unsignedp = TREE_UNSIGNED (final_type);
4071 /* In addition to the cases of two conversions in a row
4072 handled below, if we are converting something to its own
4073 type via an object of identical or wider precision, neither
4074 conversion is needed. */
4075 if (inside_type == final_type
4076 && ((inter_int && final_int) || (inter_float && final_float))
4077 && inter_prec >= final_prec)
4078 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
4080 /* Likewise, if the intermediate and final types are either both
4081 float or both integer, we don't need the middle conversion if
4082 it is wider than the final type and doesn't change the signedness
4083 (for integers). Avoid this if the final type is a pointer
4084 since then we sometimes need the inner conversion. Likewise if
4085 the outer has a precision not equal to the size of its mode. */
4086 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4087 || (inter_float && inside_float))
4088 && inter_prec >= inside_prec
4089 && (inter_float || inter_unsignedp == inside_unsignedp)
4090 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4091 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4093 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4095 /* Two conversions in a row are not needed unless:
4096 - some conversion is floating-point (overstrict for now), or
4097 - the intermediate type is narrower than both initial and
4099 - the intermediate type and innermost type differ in signedness,
4100 and the outermost type is wider than the intermediate, or
4101 - the initial type is a pointer type and the precisions of the
4102 intermediate and final types differ, or
4103 - the final type is a pointer type and the precisions of the
4104 initial and intermediate types differ. */
4105 if (! inside_float && ! inter_float && ! final_float
4106 && (inter_prec > inside_prec || inter_prec > final_prec)
4107 && ! (inside_int && inter_int
4108 && inter_unsignedp != inside_unsignedp
4109 && inter_prec < final_prec)
4110 && ((inter_unsignedp && inter_prec > inside_prec)
4111 == (final_unsignedp && final_prec > inter_prec))
4112 && ! (inside_ptr && inter_prec != final_prec)
4113 && ! (final_ptr && inside_prec != inter_prec)
4114 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4115 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4117 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4120 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4121 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4122 /* Detect assigning a bitfield. */
4123 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4124 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4126 /* Don't leave an assignment inside a conversion
4127 unless assigning a bitfield. */
4128 tree prev = TREE_OPERAND (t, 0);
4129 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4130 /* First do the assignment, then return converted constant. */
4131 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4137 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4140 return fold_convert (t, arg0);
4142 #if 0 /* This loses on &"foo"[0]. */
4147 /* Fold an expression like: "foo"[2] */
4148 if (TREE_CODE (arg0) == STRING_CST
4149 && TREE_CODE (arg1) == INTEGER_CST
4150 && !TREE_INT_CST_HIGH (arg1)
4151 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
4153 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
4154 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
4155 force_fit_type (t, 0);
4162 if (TREE_CODE (arg0) == CONSTRUCTOR)
4164 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4171 TREE_CONSTANT (t) = wins;
4177 if (TREE_CODE (arg0) == INTEGER_CST)
4179 HOST_WIDE_INT low, high;
4180 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4181 TREE_INT_CST_HIGH (arg0),
4183 t = build_int_2 (low, high);
4184 TREE_TYPE (t) = type;
4186 = (TREE_OVERFLOW (arg0)
4187 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4188 TREE_CONSTANT_OVERFLOW (t)
4189 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4191 else if (TREE_CODE (arg0) == REAL_CST)
4192 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4194 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4195 return TREE_OPERAND (arg0, 0);
4197 /* Convert - (a - b) to (b - a) for non-floating-point. */
4198 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4199 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4200 TREE_OPERAND (arg0, 0));
4207 if (TREE_CODE (arg0) == INTEGER_CST)
4209 if (! TREE_UNSIGNED (type)
4210 && TREE_INT_CST_HIGH (arg0) < 0)
4212 HOST_WIDE_INT low, high;
4213 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4214 TREE_INT_CST_HIGH (arg0),
4216 t = build_int_2 (low, high);
4217 TREE_TYPE (t) = type;
4219 = (TREE_OVERFLOW (arg0)
4220 | force_fit_type (t, overflow));
4221 TREE_CONSTANT_OVERFLOW (t)
4222 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4225 else if (TREE_CODE (arg0) == REAL_CST)
4227 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4228 t = build_real (type,
4229 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4232 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4233 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4237 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4239 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4240 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4241 TREE_OPERAND (arg0, 0),
4242 fold (build1 (NEGATE_EXPR,
4243 TREE_TYPE (TREE_TYPE (arg0)),
4244 TREE_OPERAND (arg0, 1))));
4245 else if (TREE_CODE (arg0) == COMPLEX_CST)
4246 return build_complex (type, TREE_OPERAND (arg0, 0),
4247 fold (build1 (NEGATE_EXPR,
4248 TREE_TYPE (TREE_TYPE (arg0)),
4249 TREE_OPERAND (arg0, 1))));
4250 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4251 return fold (build (TREE_CODE (arg0), type,
4252 fold (build1 (CONJ_EXPR, type,
4253 TREE_OPERAND (arg0, 0))),
4254 fold (build1 (CONJ_EXPR,
4255 type, TREE_OPERAND (arg0, 1)))));
4256 else if (TREE_CODE (arg0) == CONJ_EXPR)
4257 return TREE_OPERAND (arg0, 0);
4263 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4264 ~ TREE_INT_CST_HIGH (arg0));
4265 TREE_TYPE (t) = type;
4266 force_fit_type (t, 0);
4267 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4268 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4270 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4271 return TREE_OPERAND (arg0, 0);
4275 /* A + (-B) -> A - B */
4276 if (TREE_CODE (arg1) == NEGATE_EXPR)
4277 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4278 else if (! FLOAT_TYPE_P (type))
4280 if (integer_zerop (arg1))
4281 return non_lvalue (convert (type, arg0));
4283 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4284 with a constant, and the two constants have no bits in common,
4285 we should treat this as a BIT_IOR_EXPR since this may produce more
4287 if (TREE_CODE (arg0) == BIT_AND_EXPR
4288 && TREE_CODE (arg1) == BIT_AND_EXPR
4289 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4290 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4291 && integer_zerop (const_binop (BIT_AND_EXPR,
4292 TREE_OPERAND (arg0, 1),
4293 TREE_OPERAND (arg1, 1), 0)))
4295 code = BIT_IOR_EXPR;
4299 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4300 about the case where C is a constant, just try one of the
4301 four possibilities. */
4303 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4304 && operand_equal_p (TREE_OPERAND (arg0, 1),
4305 TREE_OPERAND (arg1, 1), 0))
4306 return fold (build (MULT_EXPR, type,
4307 fold (build (PLUS_EXPR, type,
4308 TREE_OPERAND (arg0, 0),
4309 TREE_OPERAND (arg1, 0))),
4310 TREE_OPERAND (arg0, 1)));
4312 /* In IEEE floating point, x+0 may not equal x. */
4313 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4315 && real_zerop (arg1))
4316 return non_lvalue (convert (type, arg0));
4318 /* In most languages, can't associate operations on floats
4319 through parentheses. Rather than remember where the parentheses
4320 were, we don't associate floats at all. It shouldn't matter much.
4321 However, associating multiplications is only very slightly
4322 inaccurate, so do that if -ffast-math is specified. */
4323 if (FLOAT_TYPE_P (type)
4324 && ! (flag_fast_math && code == MULT_EXPR))
4327 /* The varsign == -1 cases happen only for addition and subtraction.
4328 It says that the arg that was split was really CON minus VAR.
4329 The rest of the code applies to all associative operations. */
4335 if (split_tree (arg0, code, &var, &con, &varsign))
4339 /* EXPR is (CON-VAR) +- ARG1. */
4340 /* If it is + and VAR==ARG1, return just CONST. */
4341 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4342 return convert (TREE_TYPE (t), con);
4344 /* If ARG0 is a constant, don't change things around;
4345 instead keep all the constant computations together. */
4347 if (TREE_CONSTANT (arg0))
4350 /* Otherwise return (CON +- ARG1) - VAR. */
4351 t = build (MINUS_EXPR, type,
4352 fold (build (code, type, con, arg1)), var);
4356 /* EXPR is (VAR+CON) +- ARG1. */
4357 /* If it is - and VAR==ARG1, return just CONST. */
4358 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4359 return convert (TREE_TYPE (t), con);
4361 /* If ARG0 is a constant, don't change things around;
4362 instead keep all the constant computations together. */
4364 if (TREE_CONSTANT (arg0))
4367 /* Otherwise return VAR +- (ARG1 +- CON). */
4368 tem = fold (build (code, type, arg1, con));
4369 t = build (code, type, var, tem);
4371 if (integer_zerop (tem)
4372 && (code == PLUS_EXPR || code == MINUS_EXPR))
4373 return convert (type, var);
4374 /* If we have x +/- (c - d) [c an explicit integer]
4375 change it to x -/+ (d - c) since if d is relocatable
4376 then the latter can be a single immediate insn
4377 and the former cannot. */
4378 if (TREE_CODE (tem) == MINUS_EXPR
4379 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4381 tree tem1 = TREE_OPERAND (tem, 1);
4382 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4383 TREE_OPERAND (tem, 0) = tem1;
4385 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4391 if (split_tree (arg1, code, &var, &con, &varsign))
4393 if (TREE_CONSTANT (arg1))
4398 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4400 /* EXPR is ARG0 +- (CON +- VAR). */
4401 if (TREE_CODE (t) == MINUS_EXPR
4402 && operand_equal_p (var, arg0, 0))
4404 /* If VAR and ARG0 cancel, return just CON or -CON. */
4405 if (code == PLUS_EXPR)
4406 return convert (TREE_TYPE (t), con);
4407 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4408 convert (TREE_TYPE (t), con)));
4411 t = build (TREE_CODE (t), type,
4412 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4414 if (integer_zerop (TREE_OPERAND (t, 0))
4415 && TREE_CODE (t) == PLUS_EXPR)
4416 return convert (TREE_TYPE (t), var);
4421 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4422 if (TREE_CODE (arg1) == REAL_CST)
4424 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4426 t1 = const_binop (code, arg0, arg1, 0);
4427 if (t1 != NULL_TREE)
4429 /* The return value should always have
4430 the same type as the original expression. */
4431 if (TREE_TYPE (t1) != TREE_TYPE (t))
4432 t1 = convert (TREE_TYPE (t), t1);
4439 if (! FLOAT_TYPE_P (type))
4441 if (! wins && integer_zerop (arg0))
4442 return build1 (NEGATE_EXPR, type, arg1);
4443 if (integer_zerop (arg1))
4444 return non_lvalue (convert (type, arg0));
4446 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4447 about the case where C is a constant, just try one of the
4448 four possibilities. */
4450 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4451 && operand_equal_p (TREE_OPERAND (arg0, 1),
4452 TREE_OPERAND (arg1, 1), 0))
4453 return fold (build (MULT_EXPR, type,
4454 fold (build (MINUS_EXPR, type,
4455 TREE_OPERAND (arg0, 0),
4456 TREE_OPERAND (arg1, 0))),
4457 TREE_OPERAND (arg0, 1)));
4459 /* Convert A - (-B) to A + B. */
4460 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4461 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4463 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4466 /* Except with IEEE floating point, 0-x equals -x. */
4467 if (! wins && real_zerop (arg0))
4468 return build1 (NEGATE_EXPR, type, arg1);
4469 /* Except with IEEE floating point, x-0 equals x. */
4470 if (real_zerop (arg1))
4471 return non_lvalue (convert (type, arg0));
4474 /* Fold &x - &x. This can happen from &x.foo - &x.
4475 This is unsafe for certain floats even in non-IEEE formats.
4476 In IEEE, it is unsafe because it does wrong for NaNs.
4477 Also note that operand_equal_p is always false if an operand
4480 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4481 && operand_equal_p (arg0, arg1, 0))
4482 return convert (type, integer_zero_node);
4487 if (! FLOAT_TYPE_P (type))
4489 if (integer_zerop (arg1))
4490 return omit_one_operand (type, arg1, arg0);
4491 if (integer_onep (arg1))
4492 return non_lvalue (convert (type, arg0));
4494 /* ((A / C) * C) is A if the division is an
4495 EXACT_DIV_EXPR. Since C is normally a constant,
4496 just check for one of the four possibilities. */
4498 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4499 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4500 return TREE_OPERAND (arg0, 0);
4502 /* (a * (1 << b)) is (a << b) */
4503 if (TREE_CODE (arg1) == LSHIFT_EXPR
4504 && integer_onep (TREE_OPERAND (arg1, 0)))
4505 return fold (build (LSHIFT_EXPR, type, arg0,
4506 TREE_OPERAND (arg1, 1)));
4507 if (TREE_CODE (arg0) == LSHIFT_EXPR
4508 && integer_onep (TREE_OPERAND (arg0, 0)))
4509 return fold (build (LSHIFT_EXPR, type, arg1,
4510 TREE_OPERAND (arg0, 1)));
4514 /* x*0 is 0, except for IEEE floating point. */
4515 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4517 && real_zerop (arg1))
4518 return omit_one_operand (type, arg1, arg0);
4519 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4520 However, ANSI says we can drop signals,
4521 so we can do this anyway. */
4522 if (real_onep (arg1))
4523 return non_lvalue (convert (type, arg0));
4525 if (! wins && real_twop (arg1) && current_function_decl != 0)
4527 tree arg = save_expr (arg0);
4528 return build (PLUS_EXPR, type, arg, arg);
4536 register enum tree_code code0, code1;
4538 if (integer_all_onesp (arg1))
4539 return omit_one_operand (type, arg1, arg0);
4540 if (integer_zerop (arg1))
4541 return non_lvalue (convert (type, arg0));
4542 t1 = distribute_bit_expr (code, type, arg0, arg1);
4543 if (t1 != NULL_TREE)
4546 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4547 is a rotate of A by C1 bits. */
4548 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4549 is a rotate of A by B bits. */
4551 code0 = TREE_CODE (arg0);
4552 code1 = TREE_CODE (arg1);
4553 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4554 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4555 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4556 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4558 register tree tree01, tree11;
4559 register enum tree_code code01, code11;
4561 tree01 = TREE_OPERAND (arg0, 1);
4562 tree11 = TREE_OPERAND (arg1, 1);
4563 code01 = TREE_CODE (tree01);
4564 code11 = TREE_CODE (tree11);
4565 if (code01 == INTEGER_CST
4566 && code11 == INTEGER_CST
4567 && TREE_INT_CST_HIGH (tree01) == 0
4568 && TREE_INT_CST_HIGH (tree11) == 0
4569 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4570 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4571 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4572 code0 == LSHIFT_EXPR ? tree01 : tree11);
4573 else if (code11 == MINUS_EXPR
4574 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4575 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4576 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4577 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4578 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4579 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4580 type, TREE_OPERAND (arg0, 0), tree01);
4581 else if (code01 == MINUS_EXPR
4582 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4583 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4584 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4585 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4586 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4587 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4588 type, TREE_OPERAND (arg0, 0), tree11);
4595 if (integer_zerop (arg1))
4596 return non_lvalue (convert (type, arg0));
4597 if (integer_all_onesp (arg1))
4598 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4603 if (integer_all_onesp (arg1))
4604 return non_lvalue (convert (type, arg0));
4605 if (integer_zerop (arg1))
4606 return omit_one_operand (type, arg1, arg0);
4607 t1 = distribute_bit_expr (code, type, arg0, arg1);
4608 if (t1 != NULL_TREE)
4610 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4611 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4612 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4614 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4615 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4616 && (~TREE_INT_CST_LOW (arg0)
4617 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4618 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4620 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4621 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4623 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4624 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4625 && (~TREE_INT_CST_LOW (arg1)
4626 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4627 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4631 case BIT_ANDTC_EXPR:
4632 if (integer_all_onesp (arg0))
4633 return non_lvalue (convert (type, arg1));
4634 if (integer_zerop (arg0))
4635 return omit_one_operand (type, arg0, arg1);
4636 if (TREE_CODE (arg1) == INTEGER_CST)
4638 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4639 code = BIT_AND_EXPR;
4645 /* In most cases, do nothing with a divide by zero. */
4646 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4647 #ifndef REAL_INFINITY
4648 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4651 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4653 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4654 However, ANSI says we can drop signals, so we can do this anyway. */
4655 if (real_onep (arg1))
4656 return non_lvalue (convert (type, arg0));
4658 /* If ARG1 is a constant, we can convert this to a multiply by the
4659 reciprocal. This does not have the same rounding properties,
4660 so only do this if -ffast-math. We can actually always safely
4661 do it if ARG1 is a power of two, but it's hard to tell if it is
4662 or not in a portable manner. */
4663 if (TREE_CODE (arg1) == REAL_CST)
4666 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4668 return fold (build (MULT_EXPR, type, arg0, tem));
4669 /* Find the reciprocal if optimizing and the result is exact. */
4673 r = TREE_REAL_CST (arg1);
4674 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4676 tem = build_real (type, r);
4677 return fold (build (MULT_EXPR, type, arg0, tem));
4683 case TRUNC_DIV_EXPR:
4684 case ROUND_DIV_EXPR:
4685 case FLOOR_DIV_EXPR:
4687 case EXACT_DIV_EXPR:
4688 if (integer_onep (arg1))
4689 return non_lvalue (convert (type, arg0));
4690 if (integer_zerop (arg1))
4693 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
4694 operation, EXACT_DIV_EXPR.
4696 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
4697 At one time others generated faster code, it's not clear if they do
4698 after the last round to changes to the DIV code in expmed.c. */
4699 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
4700 && multiple_of_p (type, arg0, arg1))
4701 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
4703 /* If we have ((a / C1) / C2) where both division are the same type, try
4704 to simplify. First see if C1 * C2 overflows or not. */
4705 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4706 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4710 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4711 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4713 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4714 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4716 /* If no overflow, divide by C1*C2. */
4717 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4721 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4722 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4723 expressions, which often appear in the offsets or sizes of
4724 objects with a varying size. Only deal with positive divisors
4725 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4727 Look for NOPs and SAVE_EXPRs inside. */
4729 if (TREE_CODE (arg1) == INTEGER_CST
4730 && tree_int_cst_sgn (arg1) >= 0)
4732 int have_save_expr = 0;
4733 tree c2 = integer_zero_node;
4736 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4737 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4741 /* Look inside the dividend and simplify using EXACT_DIV_EXPR
4743 if (TREE_CODE (xarg0) == MULT_EXPR
4744 && multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
4748 t = fold (build (MULT_EXPR, type,
4749 fold (build (EXACT_DIV_EXPR, type,
4750 TREE_OPERAND (xarg0, 0), arg1)),
4751 TREE_OPERAND (xarg0, 1)));
4758 if (TREE_CODE (xarg0) == MULT_EXPR
4759 && multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
4763 t = fold (build (MULT_EXPR, type,
4764 fold (build (EXACT_DIV_EXPR, type,
4765 TREE_OPERAND (xarg0, 1), arg1)),
4766 TREE_OPERAND (xarg0, 0)));
4772 if (TREE_CODE (xarg0) == PLUS_EXPR
4773 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4774 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4775 else if (TREE_CODE (xarg0) == MINUS_EXPR
4776 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4777 /* If we are doing this computation unsigned, the negate
4779 && ! TREE_UNSIGNED (type))
4781 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4782 xarg0 = TREE_OPERAND (xarg0, 0);
4785 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4786 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4790 if (TREE_CODE (xarg0) == MULT_EXPR
4791 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4792 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4793 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4794 TREE_OPERAND (xarg0, 1), arg1, 1))
4795 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4796 TREE_OPERAND (xarg0, 1), 1)))
4797 && (tree_int_cst_sgn (c2) >= 0
4798 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4801 tree outer_div = integer_one_node;
4802 tree c1 = TREE_OPERAND (xarg0, 1);
4805 /* If C3 > C1, set them equal and do a divide by
4806 C3/C1 at the end of the operation. */
4807 if (tree_int_cst_lt (c1, c3))
4808 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4810 /* The result is A * (C1/C3) + (C2/C3). */
4811 t = fold (build (PLUS_EXPR, type,
4812 fold (build (MULT_EXPR, type,
4813 TREE_OPERAND (xarg0, 0),
4814 const_binop (code, c1, c3, 1))),
4815 const_binop (code, c2, c3, 1)));
4817 if (! integer_onep (outer_div))
4818 t = fold (build (code, type, t, convert (type, outer_div)));
4830 case FLOOR_MOD_EXPR:
4831 case ROUND_MOD_EXPR:
4832 case TRUNC_MOD_EXPR:
4833 if (integer_onep (arg1))
4834 return omit_one_operand (type, integer_zero_node, arg0);
4835 if (integer_zerop (arg1))
4838 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4839 where C1 % C3 == 0. Handle similarly to the division case,
4840 but don't bother with SAVE_EXPRs. */
4842 if (TREE_CODE (arg1) == INTEGER_CST
4843 && ! integer_zerop (arg1))
4845 tree c2 = integer_zero_node;
4848 if (TREE_CODE (xarg0) == PLUS_EXPR
4849 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4850 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4851 else if (TREE_CODE (xarg0) == MINUS_EXPR
4852 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4853 && ! TREE_UNSIGNED (type))
4855 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4856 xarg0 = TREE_OPERAND (xarg0, 0);
4861 if (TREE_CODE (xarg0) == MULT_EXPR
4862 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4863 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4864 TREE_OPERAND (xarg0, 1),
4866 && tree_int_cst_sgn (c2) >= 0)
4867 /* The result is (C2%C3). */
4868 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4869 TREE_OPERAND (xarg0, 0));
4878 if (integer_zerop (arg1))
4879 return non_lvalue (convert (type, arg0));
4880 /* Since negative shift count is not well-defined,
4881 don't try to compute it in the compiler. */
4882 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4884 /* Rewrite an LROTATE_EXPR by a constant into an
4885 RROTATE_EXPR by a new constant. */
4886 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4888 TREE_SET_CODE (t, RROTATE_EXPR);
4889 code = RROTATE_EXPR;
4890 TREE_OPERAND (t, 1) = arg1
4893 convert (TREE_TYPE (arg1),
4894 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4896 if (tree_int_cst_sgn (arg1) < 0)
4900 /* If we have a rotate of a bit operation with the rotate count and
4901 the second operand of the bit operation both constant,
4902 permute the two operations. */
4903 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4904 && (TREE_CODE (arg0) == BIT_AND_EXPR
4905 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4906 || TREE_CODE (arg0) == BIT_IOR_EXPR
4907 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4908 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4909 return fold (build (TREE_CODE (arg0), type,
4910 fold (build (code, type,
4911 TREE_OPERAND (arg0, 0), arg1)),
4912 fold (build (code, type,
4913 TREE_OPERAND (arg0, 1), arg1))));
4915 /* Two consecutive rotates adding up to the width of the mode can
4917 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4918 && TREE_CODE (arg0) == RROTATE_EXPR
4919 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4920 && TREE_INT_CST_HIGH (arg1) == 0
4921 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4922 && ((TREE_INT_CST_LOW (arg1)
4923 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4924 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4925 return TREE_OPERAND (arg0, 0);
4930 if (operand_equal_p (arg0, arg1, 0))
4932 if (INTEGRAL_TYPE_P (type)
4933 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4934 return omit_one_operand (type, arg1, arg0);
4938 if (operand_equal_p (arg0, arg1, 0))
4940 if (INTEGRAL_TYPE_P (type)
4941 && TYPE_MAX_VALUE (type)
4942 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4943 return omit_one_operand (type, arg1, arg0);
4946 case TRUTH_NOT_EXPR:
4947 /* Note that the operand of this must be an int
4948 and its values must be 0 or 1.
4949 ("true" is a fixed value perhaps depending on the language,
4950 but we don't handle values other than 1 correctly yet.) */
4951 tem = invert_truthvalue (arg0);
4952 /* Avoid infinite recursion. */
4953 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4955 return convert (type, tem);
4957 case TRUTH_ANDIF_EXPR:
4958 /* Note that the operands of this must be ints
4959 and their values must be 0 or 1.
4960 ("true" is a fixed value perhaps depending on the language.) */
4961 /* If first arg is constant zero, return it. */
4962 if (integer_zerop (arg0))
4964 case TRUTH_AND_EXPR:
4965 /* If either arg is constant true, drop it. */
4966 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4967 return non_lvalue (arg1);
4968 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4969 return non_lvalue (arg0);
4970 /* If second arg is constant zero, result is zero, but first arg
4971 must be evaluated. */
4972 if (integer_zerop (arg1))
4973 return omit_one_operand (type, arg1, arg0);
4974 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4975 case will be handled here. */
4976 if (integer_zerop (arg0))
4977 return omit_one_operand (type, arg0, arg1);
4980 /* We only do these simplifications if we are optimizing. */
4984 /* Check for things like (A || B) && (A || C). We can convert this
4985 to A || (B && C). Note that either operator can be any of the four
4986 truth and/or operations and the transformation will still be
4987 valid. Also note that we only care about order for the
4988 ANDIF and ORIF operators. If B contains side effects, this
4989 might change the truth-value of A. */
4990 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4991 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4992 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4993 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4994 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
4995 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
4997 tree a00 = TREE_OPERAND (arg0, 0);
4998 tree a01 = TREE_OPERAND (arg0, 1);
4999 tree a10 = TREE_OPERAND (arg1, 0);
5000 tree a11 = TREE_OPERAND (arg1, 1);
5001 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5002 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5003 && (code == TRUTH_AND_EXPR
5004 || code == TRUTH_OR_EXPR));
5006 if (operand_equal_p (a00, a10, 0))
5007 return fold (build (TREE_CODE (arg0), type, a00,
5008 fold (build (code, type, a01, a11))));
5009 else if (commutative && operand_equal_p (a00, a11, 0))
5010 return fold (build (TREE_CODE (arg0), type, a00,
5011 fold (build (code, type, a01, a10))));
5012 else if (commutative && operand_equal_p (a01, a10, 0))
5013 return fold (build (TREE_CODE (arg0), type, a01,
5014 fold (build (code, type, a00, a11))));
5016 /* This case if tricky because we must either have commutative
5017 operators or else A10 must not have side-effects. */
5019 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
5020 && operand_equal_p (a01, a11, 0))
5021 return fold (build (TREE_CODE (arg0), type,
5022 fold (build (code, type, a00, a10)),
5026 /* See if we can build a range comparison. */
5027 if (0 != (tem = fold_range_test (t)))
5030 /* Check for the possibility of merging component references. If our
5031 lhs is another similar operation, try to merge its rhs with our
5032 rhs. Then try to merge our lhs and rhs. */
5033 if (TREE_CODE (arg0) == code
5034 && 0 != (tem = fold_truthop (code, type,
5035 TREE_OPERAND (arg0, 1), arg1)))
5036 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
5038 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
5043 case TRUTH_ORIF_EXPR:
5044 /* Note that the operands of this must be ints
5045 and their values must be 0 or true.
5046 ("true" is a fixed value perhaps depending on the language.) */
5047 /* If first arg is constant true, return it. */
5048 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5051 /* If either arg is constant zero, drop it. */
5052 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
5053 return non_lvalue (arg1);
5054 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
5055 return non_lvalue (arg0);
5056 /* If second arg is constant true, result is true, but we must
5057 evaluate first arg. */
5058 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5059 return omit_one_operand (type, arg1, arg0);
5060 /* Likewise for first arg, but note this only occurs here for
5062 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5063 return omit_one_operand (type, arg0, arg1);
5066 case TRUTH_XOR_EXPR:
5067 /* If either arg is constant zero, drop it. */
5068 if (integer_zerop (arg0))
5069 return non_lvalue (arg1);
5070 if (integer_zerop (arg1))
5071 return non_lvalue (arg0);
5072 /* If either arg is constant true, this is a logical inversion. */
5073 if (integer_onep (arg0))
5074 return non_lvalue (invert_truthvalue (arg1));
5075 if (integer_onep (arg1))
5076 return non_lvalue (invert_truthvalue (arg0));
5085 /* If one arg is a constant integer, put it last. */
5086 if (TREE_CODE (arg0) == INTEGER_CST
5087 && TREE_CODE (arg1) != INTEGER_CST)
5089 TREE_OPERAND (t, 0) = arg1;
5090 TREE_OPERAND (t, 1) = arg0;
5091 arg0 = TREE_OPERAND (t, 0);
5092 arg1 = TREE_OPERAND (t, 1);
5093 code = swap_tree_comparison (code);
5094 TREE_SET_CODE (t, code);
5097 /* Convert foo++ == CONST into ++foo == CONST + INCR.
5098 First, see if one arg is constant; find the constant arg
5099 and the other one. */
5101 tree constop = 0, varop;
5102 int constopnum = -1;
5104 if (TREE_CONSTANT (arg1))
5105 constopnum = 1, constop = arg1, varop = arg0;
5106 if (TREE_CONSTANT (arg0))
5107 constopnum = 0, constop = arg0, varop = arg1;
5109 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
5111 /* This optimization is invalid for ordered comparisons
5112 if CONST+INCR overflows or if foo+incr might overflow.
5113 This optimization is invalid for floating point due to rounding.
5114 For pointer types we assume overflow doesn't happen. */
5115 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5116 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5117 && (code == EQ_EXPR || code == NE_EXPR)))
5120 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
5121 constop, TREE_OPERAND (varop, 1)));
5122 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
5124 /* If VAROP is a reference to a bitfield, we must mask
5125 the constant by the width of the field. */
5126 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5127 && DECL_BIT_FIELD(TREE_OPERAND
5128 (TREE_OPERAND (varop, 0), 1)))
5131 = TREE_INT_CST_LOW (DECL_SIZE
5133 (TREE_OPERAND (varop, 0), 1)));
5135 newconst = fold (build (BIT_AND_EXPR,
5136 TREE_TYPE (varop), newconst,
5137 convert (TREE_TYPE (varop),
5138 build_int_2 (size, 0))));
5142 t = build (code, type, TREE_OPERAND (t, 0),
5143 TREE_OPERAND (t, 1));
5144 TREE_OPERAND (t, constopnum) = newconst;
5148 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
5150 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5151 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5152 && (code == EQ_EXPR || code == NE_EXPR)))
5155 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
5156 constop, TREE_OPERAND (varop, 1)));
5157 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
5159 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5160 && DECL_BIT_FIELD(TREE_OPERAND
5161 (TREE_OPERAND (varop, 0), 1)))
5164 = TREE_INT_CST_LOW (DECL_SIZE
5166 (TREE_OPERAND (varop, 0), 1)));
5168 newconst = fold (build (BIT_AND_EXPR,
5169 TREE_TYPE (varop), newconst,
5170 convert (TREE_TYPE (varop),
5171 build_int_2 (size, 0))));
5175 t = build (code, type, TREE_OPERAND (t, 0),
5176 TREE_OPERAND (t, 1));
5177 TREE_OPERAND (t, constopnum) = newconst;
5183 /* Change X >= CST to X > (CST - 1) if CST is positive. */
5184 if (TREE_CODE (arg1) == INTEGER_CST
5185 && TREE_CODE (arg0) != INTEGER_CST
5186 && tree_int_cst_sgn (arg1) > 0)
5188 switch (TREE_CODE (t))
5192 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5193 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5198 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5199 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5207 /* If this is an EQ or NE comparison with zero and ARG0 is
5208 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5209 two operations, but the latter can be done in one less insn
5210 on machines that have only two-operand insns or on which a
5211 constant cannot be the first operand. */
5212 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5213 && TREE_CODE (arg0) == BIT_AND_EXPR)
5215 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5216 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5218 fold (build (code, type,
5219 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5221 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5222 TREE_OPERAND (arg0, 1),
5223 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5224 convert (TREE_TYPE (arg0),
5227 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5228 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5230 fold (build (code, type,
5231 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5233 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5234 TREE_OPERAND (arg0, 0),
5235 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5236 convert (TREE_TYPE (arg0),
5241 /* If this is an NE or EQ comparison of zero against the result of a
5242 signed MOD operation whose second operand is a power of 2, make
5243 the MOD operation unsigned since it is simpler and equivalent. */
5244 if ((code == NE_EXPR || code == EQ_EXPR)
5245 && integer_zerop (arg1)
5246 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5247 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5248 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5249 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5250 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5251 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5253 tree newtype = unsigned_type (TREE_TYPE (arg0));
5254 tree newmod = build (TREE_CODE (arg0), newtype,
5255 convert (newtype, TREE_OPERAND (arg0, 0)),
5256 convert (newtype, TREE_OPERAND (arg0, 1)));
5258 return build (code, type, newmod, convert (newtype, arg1));
5261 /* If this is an NE comparison of zero with an AND of one, remove the
5262 comparison since the AND will give the correct value. */
5263 if (code == NE_EXPR && integer_zerop (arg1)
5264 && TREE_CODE (arg0) == BIT_AND_EXPR
5265 && integer_onep (TREE_OPERAND (arg0, 1)))
5266 return convert (type, arg0);
5268 /* If we have (A & C) == C where C is a power of 2, convert this into
5269 (A & C) != 0. Similarly for NE_EXPR. */
5270 if ((code == EQ_EXPR || code == NE_EXPR)
5271 && TREE_CODE (arg0) == BIT_AND_EXPR
5272 && integer_pow2p (TREE_OPERAND (arg0, 1))
5273 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5274 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5275 arg0, integer_zero_node);
5277 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5278 and similarly for >= into !=. */
5279 if ((code == LT_EXPR || code == GE_EXPR)
5280 && TREE_UNSIGNED (TREE_TYPE (arg0))
5281 && TREE_CODE (arg1) == LSHIFT_EXPR
5282 && integer_onep (TREE_OPERAND (arg1, 0)))
5283 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5284 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5285 TREE_OPERAND (arg1, 1)),
5286 convert (TREE_TYPE (arg0), integer_zero_node));
5288 else if ((code == LT_EXPR || code == GE_EXPR)
5289 && TREE_UNSIGNED (TREE_TYPE (arg0))
5290 && (TREE_CODE (arg1) == NOP_EXPR
5291 || TREE_CODE (arg1) == CONVERT_EXPR)
5292 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5293 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5295 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5296 convert (TREE_TYPE (arg0),
5297 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5298 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5299 convert (TREE_TYPE (arg0), integer_zero_node));
5301 /* Simplify comparison of something with itself. (For IEEE
5302 floating-point, we can only do some of these simplifications.) */
5303 if (operand_equal_p (arg0, arg1, 0))
5310 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5312 if (type == integer_type_node)
5313 return integer_one_node;
5315 t = build_int_2 (1, 0);
5316 TREE_TYPE (t) = type;
5320 TREE_SET_CODE (t, code);
5324 /* For NE, we can only do this simplification if integer. */
5325 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5327 /* ... fall through ... */
5330 if (type == integer_type_node)
5331 return integer_zero_node;
5333 t = build_int_2 (0, 0);
5334 TREE_TYPE (t) = type;
5341 /* An unsigned comparison against 0 can be simplified. */
5342 if (integer_zerop (arg1)
5343 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5344 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5345 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5347 switch (TREE_CODE (t))
5351 TREE_SET_CODE (t, NE_EXPR);
5355 TREE_SET_CODE (t, EQ_EXPR);
5358 return omit_one_operand (type,
5359 convert (type, integer_one_node),
5362 return omit_one_operand (type,
5363 convert (type, integer_zero_node),
5370 /* An unsigned <= 0x7fffffff can be simplified. */
5372 int width = TYPE_PRECISION (TREE_TYPE (arg1));
5373 if (TREE_CODE (arg1) == INTEGER_CST
5374 && ! TREE_CONSTANT_OVERFLOW (arg1)
5375 && width <= HOST_BITS_PER_WIDE_INT
5376 && TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
5377 && TREE_INT_CST_HIGH (arg1) == 0
5378 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5379 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5380 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5382 switch (TREE_CODE (t))
5385 return fold (build (GE_EXPR, type,
5386 convert (signed_type (TREE_TYPE (arg0)),
5388 convert (signed_type (TREE_TYPE (arg1)),
5389 integer_zero_node)));
5391 return fold (build (LT_EXPR, type,
5392 convert (signed_type (TREE_TYPE (arg0)),
5394 convert (signed_type (TREE_TYPE (arg1)),
5395 integer_zero_node)));
5402 /* If we are comparing an expression that just has comparisons
5403 of two integer values, arithmetic expressions of those comparisons,
5404 and constants, we can simplify it. There are only three cases
5405 to check: the two values can either be equal, the first can be
5406 greater, or the second can be greater. Fold the expression for
5407 those three values. Since each value must be 0 or 1, we have
5408 eight possibilities, each of which corresponds to the constant 0
5409 or 1 or one of the six possible comparisons.
5411 This handles common cases like (a > b) == 0 but also handles
5412 expressions like ((x > y) - (y > x)) > 0, which supposedly
5413 occur in macroized code. */
5415 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5417 tree cval1 = 0, cval2 = 0;
5420 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5421 /* Don't handle degenerate cases here; they should already
5422 have been handled anyway. */
5423 && cval1 != 0 && cval2 != 0
5424 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5425 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5426 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5427 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
5428 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
5429 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5430 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5432 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5433 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5435 /* We can't just pass T to eval_subst in case cval1 or cval2
5436 was the same as ARG1. */
5439 = fold (build (code, type,
5440 eval_subst (arg0, cval1, maxval, cval2, minval),
5443 = fold (build (code, type,
5444 eval_subst (arg0, cval1, maxval, cval2, maxval),
5447 = fold (build (code, type,
5448 eval_subst (arg0, cval1, minval, cval2, maxval),
5451 /* All three of these results should be 0 or 1. Confirm they
5452 are. Then use those values to select the proper code
5455 if ((integer_zerop (high_result)
5456 || integer_onep (high_result))
5457 && (integer_zerop (equal_result)
5458 || integer_onep (equal_result))
5459 && (integer_zerop (low_result)
5460 || integer_onep (low_result)))
5462 /* Make a 3-bit mask with the high-order bit being the
5463 value for `>', the next for '=', and the low for '<'. */
5464 switch ((integer_onep (high_result) * 4)
5465 + (integer_onep (equal_result) * 2)
5466 + integer_onep (low_result))
5470 return omit_one_operand (type, integer_zero_node, arg0);
5491 return omit_one_operand (type, integer_one_node, arg0);
5494 t = build (code, type, cval1, cval2);
5496 return save_expr (t);
5503 /* If this is a comparison of a field, we may be able to simplify it. */
5504 if ((TREE_CODE (arg0) == COMPONENT_REF
5505 || TREE_CODE (arg0) == BIT_FIELD_REF)
5506 && (code == EQ_EXPR || code == NE_EXPR)
5507 /* Handle the constant case even without -O
5508 to make sure the warnings are given. */
5509 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5511 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5515 /* If this is a comparison of complex values and either or both
5516 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5517 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5518 may prevent needless evaluations. */
5519 if ((code == EQ_EXPR || code == NE_EXPR)
5520 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5521 && (TREE_CODE (arg0) == COMPLEX_EXPR
5522 || TREE_CODE (arg1) == COMPLEX_EXPR))
5524 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5525 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5526 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5527 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5528 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5530 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5533 fold (build (code, type, real0, real1)),
5534 fold (build (code, type, imag0, imag1))));
5537 /* From here on, the only cases we handle are when the result is
5538 known to be a constant.
5540 To compute GT, swap the arguments and do LT.
5541 To compute GE, do LT and invert the result.
5542 To compute LE, swap the arguments, do LT and invert the result.
5543 To compute NE, do EQ and invert the result.
5545 Therefore, the code below must handle only EQ and LT. */
5547 if (code == LE_EXPR || code == GT_EXPR)
5549 tem = arg0, arg0 = arg1, arg1 = tem;
5550 code = swap_tree_comparison (code);
5553 /* Note that it is safe to invert for real values here because we
5554 will check below in the one case that it matters. */
5557 if (code == NE_EXPR || code == GE_EXPR)
5560 code = invert_tree_comparison (code);
5563 /* Compute a result for LT or EQ if args permit;
5564 otherwise return T. */
5565 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5567 if (code == EQ_EXPR)
5568 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5569 == TREE_INT_CST_LOW (arg1))
5570 && (TREE_INT_CST_HIGH (arg0)
5571 == TREE_INT_CST_HIGH (arg1)),
5574 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5575 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5576 : INT_CST_LT (arg0, arg1)),
5580 #if 0 /* This is no longer useful, but breaks some real code. */
5581 /* Assume a nonexplicit constant cannot equal an explicit one,
5582 since such code would be undefined anyway.
5583 Exception: on sysvr4, using #pragma weak,
5584 a label can come out as 0. */
5585 else if (TREE_CODE (arg1) == INTEGER_CST
5586 && !integer_zerop (arg1)
5587 && TREE_CONSTANT (arg0)
5588 && TREE_CODE (arg0) == ADDR_EXPR
5590 t1 = build_int_2 (0, 0);
5592 /* Two real constants can be compared explicitly. */
5593 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5595 /* If either operand is a NaN, the result is false with two
5596 exceptions: First, an NE_EXPR is true on NaNs, but that case
5597 is already handled correctly since we will be inverting the
5598 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5599 or a GE_EXPR into a LT_EXPR, we must return true so that it
5600 will be inverted into false. */
5602 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5603 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5604 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5606 else if (code == EQ_EXPR)
5607 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5608 TREE_REAL_CST (arg1)),
5611 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5612 TREE_REAL_CST (arg1)),
5616 if (t1 == NULL_TREE)
5620 TREE_INT_CST_LOW (t1) ^= 1;
5622 TREE_TYPE (t1) = type;
5626 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5627 so all simple results must be passed through pedantic_non_lvalue. */
5628 if (TREE_CODE (arg0) == INTEGER_CST)
5629 return pedantic_non_lvalue
5630 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5631 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5632 return pedantic_omit_one_operand (type, arg1, arg0);
5634 /* If the second operand is zero, invert the comparison and swap
5635 the second and third operands. Likewise if the second operand
5636 is constant and the third is not or if the third operand is
5637 equivalent to the first operand of the comparison. */
5639 if (integer_zerop (arg1)
5640 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5641 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5642 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5643 TREE_OPERAND (t, 2),
5644 TREE_OPERAND (arg0, 1))))
5646 /* See if this can be inverted. If it can't, possibly because
5647 it was a floating-point inequality comparison, don't do
5649 tem = invert_truthvalue (arg0);
5651 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5653 t = build (code, type, tem,
5654 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5656 arg1 = TREE_OPERAND (t, 2);
5661 /* If we have A op B ? A : C, we may be able to convert this to a
5662 simpler expression, depending on the operation and the values
5663 of B and C. IEEE floating point prevents this though,
5664 because A or B might be -0.0 or a NaN. */
5666 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5667 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5668 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5670 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5671 arg1, TREE_OPERAND (arg0, 1)))
5673 tree arg2 = TREE_OPERAND (t, 2);
5674 enum tree_code comp_code = TREE_CODE (arg0);
5678 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5679 depending on the comparison operation. */
5680 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5681 ? real_zerop (TREE_OPERAND (arg0, 1))
5682 : integer_zerop (TREE_OPERAND (arg0, 1)))
5683 && TREE_CODE (arg2) == NEGATE_EXPR
5684 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5688 return pedantic_non_lvalue
5689 (fold (build1 (NEGATE_EXPR, type, arg1)));
5691 return pedantic_non_lvalue (convert (type, arg1));
5694 return pedantic_non_lvalue
5695 (convert (type, fold (build1 (ABS_EXPR,
5696 TREE_TYPE (arg1), arg1))));
5699 return pedantic_non_lvalue
5700 (fold (build1 (NEGATE_EXPR, type,
5702 fold (build1 (ABS_EXPR,
5709 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5712 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5714 if (comp_code == NE_EXPR)
5715 return pedantic_non_lvalue (convert (type, arg1));
5716 else if (comp_code == EQ_EXPR)
5717 return pedantic_non_lvalue (convert (type, integer_zero_node));
5720 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5721 or max (A, B), depending on the operation. */
5723 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5724 arg2, TREE_OPERAND (arg0, 0)))
5726 tree comp_op0 = TREE_OPERAND (arg0, 0);
5727 tree comp_op1 = TREE_OPERAND (arg0, 1);
5728 tree comp_type = TREE_TYPE (comp_op0);
5733 return pedantic_non_lvalue (convert (type, arg2));
5735 return pedantic_non_lvalue (convert (type, arg1));
5738 /* In C++ a ?: expression can be an lvalue, so put the
5739 operand which will be used if they are equal first
5740 so that we can convert this back to the
5741 corresponding COND_EXPR. */
5742 return pedantic_non_lvalue
5743 (convert (type, (fold (build (MIN_EXPR, comp_type,
5744 (comp_code == LE_EXPR
5745 ? comp_op0 : comp_op1),
5746 (comp_code == LE_EXPR
5747 ? comp_op1 : comp_op0))))));
5751 return pedantic_non_lvalue
5752 (convert (type, fold (build (MAX_EXPR, comp_type,
5753 (comp_code == GE_EXPR
5754 ? comp_op0 : comp_op1),
5755 (comp_code == GE_EXPR
5756 ? comp_op1 : comp_op0)))));
5763 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5764 we might still be able to simplify this. For example,
5765 if C1 is one less or one more than C2, this might have started
5766 out as a MIN or MAX and been transformed by this function.
5767 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5769 if (INTEGRAL_TYPE_P (type)
5770 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5771 && TREE_CODE (arg2) == INTEGER_CST)
5775 /* We can replace A with C1 in this case. */
5776 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5777 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5778 TREE_OPERAND (t, 2));
5782 /* If C1 is C2 + 1, this is min(A, C2). */
5783 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5784 && operand_equal_p (TREE_OPERAND (arg0, 1),
5785 const_binop (PLUS_EXPR, arg2,
5786 integer_one_node, 0), 1))
5787 return pedantic_non_lvalue
5788 (fold (build (MIN_EXPR, type, arg1, arg2)));
5792 /* If C1 is C2 - 1, this is min(A, C2). */
5793 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5794 && operand_equal_p (TREE_OPERAND (arg0, 1),
5795 const_binop (MINUS_EXPR, arg2,
5796 integer_one_node, 0), 1))
5797 return pedantic_non_lvalue
5798 (fold (build (MIN_EXPR, type, arg1, arg2)));
5802 /* If C1 is C2 - 1, this is max(A, C2). */
5803 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5804 && operand_equal_p (TREE_OPERAND (arg0, 1),
5805 const_binop (MINUS_EXPR, arg2,
5806 integer_one_node, 0), 1))
5807 return pedantic_non_lvalue
5808 (fold (build (MAX_EXPR, type, arg1, arg2)));
5812 /* If C1 is C2 + 1, this is max(A, C2). */
5813 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5814 && operand_equal_p (TREE_OPERAND (arg0, 1),
5815 const_binop (PLUS_EXPR, arg2,
5816 integer_one_node, 0), 1))
5817 return pedantic_non_lvalue
5818 (fold (build (MAX_EXPR, type, arg1, arg2)));
5827 /* If the second operand is simpler than the third, swap them
5828 since that produces better jump optimization results. */
5829 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5830 || TREE_CODE (arg1) == SAVE_EXPR)
5831 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5832 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5833 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5835 /* See if this can be inverted. If it can't, possibly because
5836 it was a floating-point inequality comparison, don't do
5838 tem = invert_truthvalue (arg0);
5840 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5842 t = build (code, type, tem,
5843 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5845 arg1 = TREE_OPERAND (t, 2);
5850 /* Convert A ? 1 : 0 to simply A. */
5851 if (integer_onep (TREE_OPERAND (t, 1))
5852 && integer_zerop (TREE_OPERAND (t, 2))
5853 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5854 call to fold will try to move the conversion inside
5855 a COND, which will recurse. In that case, the COND_EXPR
5856 is probably the best choice, so leave it alone. */
5857 && type == TREE_TYPE (arg0))
5858 return pedantic_non_lvalue (arg0);
5860 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5861 operation is simply A & 2. */
5863 if (integer_zerop (TREE_OPERAND (t, 2))
5864 && TREE_CODE (arg0) == NE_EXPR
5865 && integer_zerop (TREE_OPERAND (arg0, 1))
5866 && integer_pow2p (arg1)
5867 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5868 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5870 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5875 /* When pedantic, a compound expression can be neither an lvalue
5876 nor an integer constant expression. */
5877 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5879 /* Don't let (0, 0) be null pointer constant. */
5880 if (integer_zerop (arg1))
5881 return non_lvalue (arg1);
5886 return build_complex (type, arg0, arg1);
5890 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5892 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5893 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5894 TREE_OPERAND (arg0, 1));
5895 else if (TREE_CODE (arg0) == COMPLEX_CST)
5896 return TREE_REALPART (arg0);
5897 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5898 return fold (build (TREE_CODE (arg0), type,
5899 fold (build1 (REALPART_EXPR, type,
5900 TREE_OPERAND (arg0, 0))),
5901 fold (build1 (REALPART_EXPR,
5902 type, TREE_OPERAND (arg0, 1)))));
5906 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5907 return convert (type, integer_zero_node);
5908 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5909 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5910 TREE_OPERAND (arg0, 0));
5911 else if (TREE_CODE (arg0) == COMPLEX_CST)
5912 return TREE_IMAGPART (arg0);
5913 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5914 return fold (build (TREE_CODE (arg0), type,
5915 fold (build1 (IMAGPART_EXPR, type,
5916 TREE_OPERAND (arg0, 0))),
5917 fold (build1 (IMAGPART_EXPR, type,
5918 TREE_OPERAND (arg0, 1)))));
5921 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5923 case CLEANUP_POINT_EXPR:
5924 if (! has_cleanups (arg0))
5925 return TREE_OPERAND (t, 0);
5928 enum tree_code code0 = TREE_CODE (arg0);
5929 int kind0 = TREE_CODE_CLASS (code0);
5930 tree arg00 = TREE_OPERAND (arg0, 0);
5933 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5934 return fold (build1 (code0, type,
5935 fold (build1 (CLEANUP_POINT_EXPR,
5936 TREE_TYPE (arg00), arg00))));
5938 if (kind0 == '<' || kind0 == '2'
5939 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5940 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5941 || code0 == TRUTH_XOR_EXPR)
5943 arg01 = TREE_OPERAND (arg0, 1);
5945 if (TREE_CONSTANT (arg00)
5946 || ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
5947 && ! has_cleanups (arg00)))
5948 return fold (build (code0, type, arg00,
5949 fold (build1 (CLEANUP_POINT_EXPR,
5950 TREE_TYPE (arg01), arg01))));
5952 if (TREE_CONSTANT (arg01))
5953 return fold (build (code0, type,
5954 fold (build1 (CLEANUP_POINT_EXPR,
5955 TREE_TYPE (arg00), arg00)),
5964 } /* switch (code) */
5967 /* Determine if first argument is a multiple of second argument.
5968 Return 0 if it is not, or is not easily determined to so be.
5970 An example of the sort of thing we care about (at this point --
5971 this routine could surely be made more general, and expanded
5972 to do what the *_DIV_EXPR's fold() cases do now) is discovering
5975 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5981 when we know that the two `SAVE_EXPR (J * 8)' nodes are the
5982 same node (which means they will have the same value at run
5983 time, even though we don't know when they'll be assigned).
5985 This code also handles discovering that
5987 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5993 (of course) so we don't have to worry about dealing with a
5996 Note that we _look_ inside a SAVE_EXPR only to determine
5997 how it was calculated; it is not safe for fold() to do much
5998 of anything else with the internals of a SAVE_EXPR, since
5999 fold() cannot know when it will be evaluated at run time.
6000 For example, the latter example above _cannot_ be implemented
6005 or any variant thereof, since the value of J at evaluation time
6006 of the original SAVE_EXPR is not necessarily the same at the time
6007 the new expression is evaluated. The only optimization of this
6008 sort that would be valid is changing
6010 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
6016 SAVE_EXPR (I) * SAVE_EXPR (J)
6018 (where the same SAVE_EXPR (J) is used in the original and the
6019 transformed version). */
6022 multiple_of_p (type, top, bottom)
6027 if (operand_equal_p (top, bottom, 0))
6030 if (TREE_CODE (type) != INTEGER_TYPE)
6033 switch (TREE_CODE (top))
6036 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6037 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6041 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6042 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6045 /* Punt if conversion from non-integral or wider integral type. */
6046 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
6047 || (TYPE_PRECISION (type)
6048 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
6052 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
6055 if ((TREE_CODE (bottom) != INTEGER_CST)
6056 || (tree_int_cst_sgn (top) < 0)
6057 || (tree_int_cst_sgn (bottom) < 0))
6059 return integer_zerop (const_binop (TRUNC_MOD_EXPR,