1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-96, 1997 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, 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 and type from `sizetype'. */
1429 unsigned HOST_WIDE_INT number;
1432 /* Type-size nodes already made for small sizes. */
1433 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1435 if (number < 2*HOST_BITS_PER_WIDE_INT + 1
1436 && size_table[number] != 0)
1437 return size_table[number];
1438 if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
1440 push_obstacks_nochange ();
1441 /* Make this a permanent node. */
1442 end_temporary_allocation ();
1443 t = build_int_2 (number, 0);
1444 TREE_TYPE (t) = sizetype;
1445 size_table[number] = t;
1450 t = build_int_2 (number, 0);
1451 TREE_TYPE (t) = sizetype;
1452 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1457 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1458 CODE is a tree code. Data type is taken from `sizetype',
1459 If the operands are constant, so is the result. */
1462 size_binop (code, arg0, arg1)
1463 enum tree_code code;
1466 /* Handle the special case of two integer constants faster. */
1467 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1469 /* And some specific cases even faster than that. */
1470 if (code == PLUS_EXPR && integer_zerop (arg0))
1472 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1473 && integer_zerop (arg1))
1475 else if (code == MULT_EXPR && integer_onep (arg0))
1478 /* Handle general case of two integer constants. */
1479 return int_const_binop (code, arg0, arg1, 0, 1);
1482 if (arg0 == error_mark_node || arg1 == error_mark_node)
1483 return error_mark_node;
1485 return fold (build (code, sizetype, arg0, arg1));
1488 /* Given T, a tree representing type conversion of ARG1, a constant,
1489 return a constant tree representing the result of conversion. */
1492 fold_convert (t, arg1)
1496 register tree type = TREE_TYPE (t);
1499 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1501 if (TREE_CODE (arg1) == INTEGER_CST)
1503 /* If we would build a constant wider than GCC supports,
1504 leave the conversion unfolded. */
1505 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1508 /* Given an integer constant, make new constant with new type,
1509 appropriately sign-extended or truncated. */
1510 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1511 TREE_INT_CST_HIGH (arg1));
1512 TREE_TYPE (t) = type;
1513 /* Indicate an overflow if (1) ARG1 already overflowed,
1514 or (2) force_fit_type indicates an overflow.
1515 Tell force_fit_type that an overflow has already occurred
1516 if ARG1 is a too-large unsigned value and T is signed.
1517 But don't indicate an overflow if converting a pointer. */
1519 = (TREE_OVERFLOW (arg1)
1520 || (force_fit_type (t,
1521 (TREE_INT_CST_HIGH (arg1) < 0
1522 & (TREE_UNSIGNED (type)
1523 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1524 && TREE_CODE (TREE_TYPE (arg1)) != POINTER_TYPE));
1525 TREE_CONSTANT_OVERFLOW (t)
1526 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1528 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1529 else if (TREE_CODE (arg1) == REAL_CST)
1531 /* Don't initialize these, use assignments.
1532 Initialized local aggregates don't work on old compilers. */
1536 tree type1 = TREE_TYPE (arg1);
1539 x = TREE_REAL_CST (arg1);
1540 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1542 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1543 if (!no_upper_bound)
1544 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1546 /* See if X will be in range after truncation towards 0.
1547 To compensate for truncation, move the bounds away from 0,
1548 but reject if X exactly equals the adjusted bounds. */
1549 #ifdef REAL_ARITHMETIC
1550 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1551 if (!no_upper_bound)
1552 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1555 if (!no_upper_bound)
1558 /* If X is a NaN, use zero instead and show we have an overflow.
1559 Otherwise, range check. */
1560 if (REAL_VALUE_ISNAN (x))
1561 overflow = 1, x = dconst0;
1562 else if (! (REAL_VALUES_LESS (l, x)
1564 && REAL_VALUES_LESS (x, u)))
1567 #ifndef REAL_ARITHMETIC
1569 HOST_WIDE_INT low, high;
1570 HOST_WIDE_INT half_word
1571 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1576 high = (HOST_WIDE_INT) (x / half_word / half_word);
1577 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1578 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1580 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1581 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1584 low = (HOST_WIDE_INT) x;
1585 if (TREE_REAL_CST (arg1) < 0)
1586 neg_double (low, high, &low, &high);
1587 t = build_int_2 (low, high);
1591 HOST_WIDE_INT low, high;
1592 REAL_VALUE_TO_INT (&low, &high, x);
1593 t = build_int_2 (low, high);
1596 TREE_TYPE (t) = type;
1598 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1599 TREE_CONSTANT_OVERFLOW (t)
1600 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1602 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1603 TREE_TYPE (t) = type;
1605 else if (TREE_CODE (type) == REAL_TYPE)
1607 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1608 if (TREE_CODE (arg1) == INTEGER_CST)
1609 return build_real_from_int_cst (type, arg1);
1610 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1611 if (TREE_CODE (arg1) == REAL_CST)
1613 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1616 TREE_TYPE (arg1) = type;
1619 else if (setjmp (float_error))
1622 t = copy_node (arg1);
1625 set_float_handler (float_error);
1627 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1628 TREE_REAL_CST (arg1)));
1629 set_float_handler (NULL_PTR);
1633 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1634 TREE_CONSTANT_OVERFLOW (t)
1635 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1639 TREE_CONSTANT (t) = 1;
1643 /* Return an expr equal to X but certainly not valid as an lvalue.
1644 Also make sure it is not valid as an null pointer constant. */
1652 /* These things are certainly not lvalues. */
1653 if (TREE_CODE (x) == NON_LVALUE_EXPR
1654 || TREE_CODE (x) == INTEGER_CST
1655 || TREE_CODE (x) == REAL_CST
1656 || TREE_CODE (x) == STRING_CST
1657 || TREE_CODE (x) == ADDR_EXPR)
1659 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1661 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1662 so convert_for_assignment won't strip it.
1663 This is so this 0 won't be treated as a null pointer constant. */
1664 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1665 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1671 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1672 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1676 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1677 Zero means allow extended lvalues. */
1679 int pedantic_lvalues;
1681 /* When pedantic, return an expr equal to X but certainly not valid as a
1682 pedantic lvalue. Otherwise, return X. */
1685 pedantic_non_lvalue (x)
1688 if (pedantic_lvalues)
1689 return non_lvalue (x);
1694 /* Given a tree comparison code, return the code that is the logical inverse
1695 of the given code. It is not safe to do this for floating-point
1696 comparisons, except for NE_EXPR and EQ_EXPR. */
1698 static enum tree_code
1699 invert_tree_comparison (code)
1700 enum tree_code code;
1721 /* Similar, but return the comparison that results if the operands are
1722 swapped. This is safe for floating-point. */
1724 static enum tree_code
1725 swap_tree_comparison (code)
1726 enum tree_code code;
1746 /* Return nonzero if CODE is a tree code that represents a truth value. */
1749 truth_value_p (code)
1750 enum tree_code code;
1752 return (TREE_CODE_CLASS (code) == '<'
1753 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1754 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1755 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1758 /* Return nonzero if two operands are necessarily equal.
1759 If ONLY_CONST is non-zero, only return non-zero for constants.
1760 This function tests whether the operands are indistinguishable;
1761 it does not test whether they are equal using C's == operation.
1762 The distinction is important for IEEE floating point, because
1763 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1764 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1767 operand_equal_p (arg0, arg1, only_const)
1771 /* If both types don't have the same signedness, then we can't consider
1772 them equal. We must check this before the STRIP_NOPS calls
1773 because they may change the signedness of the arguments. */
1774 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1780 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1781 /* This is needed for conversions and for COMPONENT_REF.
1782 Might as well play it safe and always test this. */
1783 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1786 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1787 We don't care about side effects in that case because the SAVE_EXPR
1788 takes care of that for us. In all other cases, two expressions are
1789 equal if they have no side effects. If we have two identical
1790 expressions with side effects that should be treated the same due
1791 to the only side effects being identical SAVE_EXPR's, that will
1792 be detected in the recursive calls below. */
1793 if (arg0 == arg1 && ! only_const
1794 && (TREE_CODE (arg0) == SAVE_EXPR
1795 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1798 /* Next handle constant cases, those for which we can return 1 even
1799 if ONLY_CONST is set. */
1800 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1801 switch (TREE_CODE (arg0))
1804 return (! TREE_CONSTANT_OVERFLOW (arg0)
1805 && ! TREE_CONSTANT_OVERFLOW (arg1)
1806 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1807 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
1810 return (! TREE_CONSTANT_OVERFLOW (arg0)
1811 && ! TREE_CONSTANT_OVERFLOW (arg1)
1812 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
1813 TREE_REAL_CST (arg1)));
1816 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1818 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1822 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1823 && ! strncmp (TREE_STRING_POINTER (arg0),
1824 TREE_STRING_POINTER (arg1),
1825 TREE_STRING_LENGTH (arg0)));
1828 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1837 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1840 /* Two conversions are equal only if signedness and modes match. */
1841 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1842 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1843 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1846 return operand_equal_p (TREE_OPERAND (arg0, 0),
1847 TREE_OPERAND (arg1, 0), 0);
1851 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1852 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1856 /* For commutative ops, allow the other order. */
1857 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1858 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1859 || TREE_CODE (arg0) == BIT_IOR_EXPR
1860 || TREE_CODE (arg0) == BIT_XOR_EXPR
1861 || TREE_CODE (arg0) == BIT_AND_EXPR
1862 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1863 && operand_equal_p (TREE_OPERAND (arg0, 0),
1864 TREE_OPERAND (arg1, 1), 0)
1865 && operand_equal_p (TREE_OPERAND (arg0, 1),
1866 TREE_OPERAND (arg1, 0), 0));
1869 switch (TREE_CODE (arg0))
1872 return operand_equal_p (TREE_OPERAND (arg0, 0),
1873 TREE_OPERAND (arg1, 0), 0);
1877 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1878 TREE_OPERAND (arg1, 0), 0)
1879 && operand_equal_p (TREE_OPERAND (arg0, 1),
1880 TREE_OPERAND (arg1, 1), 0));
1883 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1884 TREE_OPERAND (arg1, 0), 0)
1885 && operand_equal_p (TREE_OPERAND (arg0, 1),
1886 TREE_OPERAND (arg1, 1), 0)
1887 && operand_equal_p (TREE_OPERAND (arg0, 2),
1888 TREE_OPERAND (arg1, 2), 0));
1898 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1899 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1901 When in doubt, return 0. */
1904 operand_equal_for_comparison_p (arg0, arg1, other)
1908 int unsignedp1, unsignedpo;
1909 tree primarg1, primother;
1910 unsigned correct_width;
1912 if (operand_equal_p (arg0, arg1, 0))
1915 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1916 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1919 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1920 actual comparison operand, ARG0.
1922 First throw away any conversions to wider types
1923 already present in the operands. */
1925 primarg1 = get_narrower (arg1, &unsignedp1);
1926 primother = get_narrower (other, &unsignedpo);
1928 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1929 if (unsignedp1 == unsignedpo
1930 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1931 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1933 tree type = TREE_TYPE (arg0);
1935 /* Make sure shorter operand is extended the right way
1936 to match the longer operand. */
1937 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1938 TREE_TYPE (primarg1)),
1941 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1948 /* See if ARG is an expression that is either a comparison or is performing
1949 arithmetic on comparisons. The comparisons must only be comparing
1950 two different values, which will be stored in *CVAL1 and *CVAL2; if
1951 they are non-zero it means that some operands have already been found.
1952 No variables may be used anywhere else in the expression except in the
1953 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1954 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1956 If this is true, return 1. Otherwise, return zero. */
1959 twoval_comparison_p (arg, cval1, cval2, save_p)
1961 tree *cval1, *cval2;
1964 enum tree_code code = TREE_CODE (arg);
1965 char class = TREE_CODE_CLASS (code);
1967 /* We can handle some of the 'e' cases here. */
1968 if (class == 'e' && code == TRUTH_NOT_EXPR)
1970 else if (class == 'e'
1971 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1972 || code == COMPOUND_EXPR))
1975 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1976 the expression. There may be no way to make this work, but it needs
1977 to be looked at again for 2.6. */
1979 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1981 /* If we've already found a CVAL1 or CVAL2, this expression is
1982 two complex to handle. */
1983 if (*cval1 || *cval2)
1994 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
1997 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
1998 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1999 cval1, cval2, save_p));
2005 if (code == COND_EXPR)
2006 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2007 cval1, cval2, save_p)
2008 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2009 cval1, cval2, save_p)
2010 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2011 cval1, cval2, save_p));
2015 /* First see if we can handle the first operand, then the second. For
2016 the second operand, we know *CVAL1 can't be zero. It must be that
2017 one side of the comparison is each of the values; test for the
2018 case where this isn't true by failing if the two operands
2021 if (operand_equal_p (TREE_OPERAND (arg, 0),
2022 TREE_OPERAND (arg, 1), 0))
2026 *cval1 = TREE_OPERAND (arg, 0);
2027 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2029 else if (*cval2 == 0)
2030 *cval2 = TREE_OPERAND (arg, 0);
2031 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2036 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2038 else if (*cval2 == 0)
2039 *cval2 = TREE_OPERAND (arg, 1);
2040 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2052 /* ARG is a tree that is known to contain just arithmetic operations and
2053 comparisons. Evaluate the operations in the tree substituting NEW0 for
2054 any occurrence of OLD0 as an operand of a comparison and likewise for
2058 eval_subst (arg, old0, new0, old1, new1)
2060 tree old0, new0, old1, new1;
2062 tree type = TREE_TYPE (arg);
2063 enum tree_code code = TREE_CODE (arg);
2064 char class = TREE_CODE_CLASS (code);
2066 /* We can handle some of the 'e' cases here. */
2067 if (class == 'e' && code == TRUTH_NOT_EXPR)
2069 else if (class == 'e'
2070 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2076 return fold (build1 (code, type,
2077 eval_subst (TREE_OPERAND (arg, 0),
2078 old0, new0, old1, new1)));
2081 return fold (build (code, type,
2082 eval_subst (TREE_OPERAND (arg, 0),
2083 old0, new0, old1, new1),
2084 eval_subst (TREE_OPERAND (arg, 1),
2085 old0, new0, old1, new1)));
2091 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2094 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2097 return fold (build (code, type,
2098 eval_subst (TREE_OPERAND (arg, 0),
2099 old0, new0, old1, new1),
2100 eval_subst (TREE_OPERAND (arg, 1),
2101 old0, new0, old1, new1),
2102 eval_subst (TREE_OPERAND (arg, 2),
2103 old0, new0, old1, new1)));
2107 /* fall through (???) */
2111 tree arg0 = TREE_OPERAND (arg, 0);
2112 tree arg1 = TREE_OPERAND (arg, 1);
2114 /* We need to check both for exact equality and tree equality. The
2115 former will be true if the operand has a side-effect. In that
2116 case, we know the operand occurred exactly once. */
2118 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2120 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2123 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2125 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2128 return fold (build (code, type, arg0, arg1));
2136 /* Return a tree for the case when the result of an expression is RESULT
2137 converted to TYPE and OMITTED was previously an operand of the expression
2138 but is now not needed (e.g., we folded OMITTED * 0).
2140 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2141 the conversion of RESULT to TYPE. */
2144 omit_one_operand (type, result, omitted)
2145 tree type, result, omitted;
2147 tree t = convert (type, result);
2149 if (TREE_SIDE_EFFECTS (omitted))
2150 return build (COMPOUND_EXPR, type, omitted, t);
2152 return non_lvalue (t);
2155 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2158 pedantic_omit_one_operand (type, result, omitted)
2159 tree type, result, omitted;
2161 tree t = convert (type, result);
2163 if (TREE_SIDE_EFFECTS (omitted))
2164 return build (COMPOUND_EXPR, type, omitted, t);
2166 return pedantic_non_lvalue (t);
2171 /* Return a simplified tree node for the truth-negation of ARG. This
2172 never alters ARG itself. We assume that ARG is an operation that
2173 returns a truth value (0 or 1). */
2176 invert_truthvalue (arg)
2179 tree type = TREE_TYPE (arg);
2180 enum tree_code code = TREE_CODE (arg);
2182 if (code == ERROR_MARK)
2185 /* If this is a comparison, we can simply invert it, except for
2186 floating-point non-equality comparisons, in which case we just
2187 enclose a TRUTH_NOT_EXPR around what we have. */
2189 if (TREE_CODE_CLASS (code) == '<')
2191 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2192 && code != NE_EXPR && code != EQ_EXPR)
2193 return build1 (TRUTH_NOT_EXPR, type, arg);
2195 return build (invert_tree_comparison (code), type,
2196 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2202 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2203 && TREE_INT_CST_HIGH (arg) == 0, 0));
2205 case TRUTH_AND_EXPR:
2206 return build (TRUTH_OR_EXPR, type,
2207 invert_truthvalue (TREE_OPERAND (arg, 0)),
2208 invert_truthvalue (TREE_OPERAND (arg, 1)));
2211 return build (TRUTH_AND_EXPR, type,
2212 invert_truthvalue (TREE_OPERAND (arg, 0)),
2213 invert_truthvalue (TREE_OPERAND (arg, 1)));
2215 case TRUTH_XOR_EXPR:
2216 /* Here we can invert either operand. We invert the first operand
2217 unless the second operand is a TRUTH_NOT_EXPR in which case our
2218 result is the XOR of the first operand with the inside of the
2219 negation of the second operand. */
2221 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2222 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2223 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2225 return build (TRUTH_XOR_EXPR, type,
2226 invert_truthvalue (TREE_OPERAND (arg, 0)),
2227 TREE_OPERAND (arg, 1));
2229 case TRUTH_ANDIF_EXPR:
2230 return build (TRUTH_ORIF_EXPR, type,
2231 invert_truthvalue (TREE_OPERAND (arg, 0)),
2232 invert_truthvalue (TREE_OPERAND (arg, 1)));
2234 case TRUTH_ORIF_EXPR:
2235 return build (TRUTH_ANDIF_EXPR, type,
2236 invert_truthvalue (TREE_OPERAND (arg, 0)),
2237 invert_truthvalue (TREE_OPERAND (arg, 1)));
2239 case TRUTH_NOT_EXPR:
2240 return TREE_OPERAND (arg, 0);
2243 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2244 invert_truthvalue (TREE_OPERAND (arg, 1)),
2245 invert_truthvalue (TREE_OPERAND (arg, 2)));
2248 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2249 invert_truthvalue (TREE_OPERAND (arg, 1)));
2251 case NON_LVALUE_EXPR:
2252 return invert_truthvalue (TREE_OPERAND (arg, 0));
2257 return build1 (TREE_CODE (arg), type,
2258 invert_truthvalue (TREE_OPERAND (arg, 0)));
2261 if (!integer_onep (TREE_OPERAND (arg, 1)))
2263 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2266 return build1 (TRUTH_NOT_EXPR, type, arg);
2268 case CLEANUP_POINT_EXPR:
2269 return build1 (CLEANUP_POINT_EXPR, type,
2270 invert_truthvalue (TREE_OPERAND (arg, 0)));
2275 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2277 return build1 (TRUTH_NOT_EXPR, type, arg);
2280 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2281 operands are another bit-wise operation with a common input. If so,
2282 distribute the bit operations to save an operation and possibly two if
2283 constants are involved. For example, convert
2284 (A | B) & (A | C) into A | (B & C)
2285 Further simplification will occur if B and C are constants.
2287 If this optimization cannot be done, 0 will be returned. */
2290 distribute_bit_expr (code, type, arg0, arg1)
2291 enum tree_code code;
2298 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2299 || TREE_CODE (arg0) == code
2300 || (TREE_CODE (arg0) != BIT_AND_EXPR
2301 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2304 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2306 common = TREE_OPERAND (arg0, 0);
2307 left = TREE_OPERAND (arg0, 1);
2308 right = TREE_OPERAND (arg1, 1);
2310 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2312 common = TREE_OPERAND (arg0, 0);
2313 left = TREE_OPERAND (arg0, 1);
2314 right = TREE_OPERAND (arg1, 0);
2316 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2318 common = TREE_OPERAND (arg0, 1);
2319 left = TREE_OPERAND (arg0, 0);
2320 right = TREE_OPERAND (arg1, 1);
2322 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2324 common = TREE_OPERAND (arg0, 1);
2325 left = TREE_OPERAND (arg0, 0);
2326 right = TREE_OPERAND (arg1, 0);
2331 return fold (build (TREE_CODE (arg0), type, common,
2332 fold (build (code, type, left, right))));
2335 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2336 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2339 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2342 int bitsize, bitpos;
2345 tree result = build (BIT_FIELD_REF, type, inner,
2346 size_int (bitsize), size_int (bitpos));
2348 TREE_UNSIGNED (result) = unsignedp;
2353 /* Optimize a bit-field compare.
2355 There are two cases: First is a compare against a constant and the
2356 second is a comparison of two items where the fields are at the same
2357 bit position relative to the start of a chunk (byte, halfword, word)
2358 large enough to contain it. In these cases we can avoid the shift
2359 implicit in bitfield extractions.
2361 For constants, we emit a compare of the shifted constant with the
2362 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2363 compared. For two fields at the same position, we do the ANDs with the
2364 similar mask and compare the result of the ANDs.
2366 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2367 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2368 are the left and right operands of the comparison, respectively.
2370 If the optimization described above can be done, we return the resulting
2371 tree. Otherwise we return zero. */
2374 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2375 enum tree_code code;
2379 int lbitpos, lbitsize, rbitpos, rbitsize;
2380 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2381 tree type = TREE_TYPE (lhs);
2382 tree signed_type, unsigned_type;
2383 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2384 enum machine_mode lmode, rmode, lnmode, rnmode;
2385 int lunsignedp, runsignedp;
2386 int lvolatilep = 0, rvolatilep = 0;
2388 tree linner, rinner;
2392 /* Get all the information about the extractions being done. If the bit size
2393 if the same as the size of the underlying object, we aren't doing an
2394 extraction at all and so can do nothing. */
2395 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2396 &lunsignedp, &lvolatilep, &alignment);
2397 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2403 /* If this is not a constant, we can only do something if bit positions,
2404 sizes, and signedness are the same. */
2405 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2406 &runsignedp, &rvolatilep, &alignment);
2408 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2409 || lunsignedp != runsignedp || offset != 0)
2413 /* See if we can find a mode to refer to this field. We should be able to,
2414 but fail if we can't. */
2415 lnmode = get_best_mode (lbitsize, lbitpos,
2416 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2418 if (lnmode == VOIDmode)
2421 /* Set signed and unsigned types of the precision of this mode for the
2423 signed_type = type_for_mode (lnmode, 0);
2424 unsigned_type = type_for_mode (lnmode, 1);
2428 rnmode = get_best_mode (rbitsize, rbitpos,
2429 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2431 if (rnmode == VOIDmode)
2435 /* Compute the bit position and size for the new reference and our offset
2436 within it. If the new reference is the same size as the original, we
2437 won't optimize anything, so return zero. */
2438 lnbitsize = GET_MODE_BITSIZE (lnmode);
2439 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2440 lbitpos -= lnbitpos;
2441 if (lnbitsize == lbitsize)
2446 rnbitsize = GET_MODE_BITSIZE (rnmode);
2447 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2448 rbitpos -= rnbitpos;
2449 if (rnbitsize == rbitsize)
2453 if (BYTES_BIG_ENDIAN)
2454 lbitpos = lnbitsize - lbitsize - lbitpos;
2456 /* Make the mask to be used against the extracted field. */
2457 mask = build_int_2 (~0, ~0);
2458 TREE_TYPE (mask) = unsigned_type;
2459 force_fit_type (mask, 0);
2460 mask = convert (unsigned_type, mask);
2461 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2462 mask = const_binop (RSHIFT_EXPR, mask,
2463 size_int (lnbitsize - lbitsize - lbitpos), 0);
2466 /* If not comparing with constant, just rework the comparison
2468 return build (code, compare_type,
2469 build (BIT_AND_EXPR, unsigned_type,
2470 make_bit_field_ref (linner, unsigned_type,
2471 lnbitsize, lnbitpos, 1),
2473 build (BIT_AND_EXPR, unsigned_type,
2474 make_bit_field_ref (rinner, unsigned_type,
2475 rnbitsize, rnbitpos, 1),
2478 /* Otherwise, we are handling the constant case. See if the constant is too
2479 big for the field. Warn and return a tree of for 0 (false) if so. We do
2480 this not only for its own sake, but to avoid having to test for this
2481 error case below. If we didn't, we might generate wrong code.
2483 For unsigned fields, the constant shifted right by the field length should
2484 be all zero. For signed fields, the high-order bits should agree with
2489 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2490 convert (unsigned_type, rhs),
2491 size_int (lbitsize), 0)))
2493 warning ("comparison is always %s due to width of bitfield",
2494 code == NE_EXPR ? "one" : "zero");
2495 return convert (compare_type,
2497 ? integer_one_node : integer_zero_node));
2502 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2503 size_int (lbitsize - 1), 0);
2504 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2506 warning ("comparison is always %s due to width of bitfield",
2507 code == NE_EXPR ? "one" : "zero");
2508 return convert (compare_type,
2510 ? integer_one_node : integer_zero_node));
2514 /* Single-bit compares should always be against zero. */
2515 if (lbitsize == 1 && ! integer_zerop (rhs))
2517 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2518 rhs = convert (type, integer_zero_node);
2521 /* Make a new bitfield reference, shift the constant over the
2522 appropriate number of bits and mask it with the computed mask
2523 (in case this was a signed field). If we changed it, make a new one. */
2524 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2527 TREE_SIDE_EFFECTS (lhs) = 1;
2528 TREE_THIS_VOLATILE (lhs) = 1;
2531 rhs = fold (const_binop (BIT_AND_EXPR,
2532 const_binop (LSHIFT_EXPR,
2533 convert (unsigned_type, rhs),
2534 size_int (lbitpos), 0),
2537 return build (code, compare_type,
2538 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2542 /* Subroutine for fold_truthop: decode a field reference.
2544 If EXP is a comparison reference, we return the innermost reference.
2546 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2547 set to the starting bit number.
2549 If the innermost field can be completely contained in a mode-sized
2550 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2552 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2553 otherwise it is not changed.
2555 *PUNSIGNEDP is set to the signedness of the field.
2557 *PMASK is set to the mask used. This is either contained in a
2558 BIT_AND_EXPR or derived from the width of the field.
2560 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2562 Return 0 if this is not a component reference or is one that we can't
2563 do anything with. */
2566 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2567 pvolatilep, pmask, pand_mask)
2569 int *pbitsize, *pbitpos;
2570 enum machine_mode *pmode;
2571 int *punsignedp, *pvolatilep;
2576 tree mask, inner, offset;
2581 /* All the optimizations using this function assume integer fields.
2582 There are problems with FP fields since the type_for_size call
2583 below can fail for, e.g., XFmode. */
2584 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2589 if (TREE_CODE (exp) == BIT_AND_EXPR)
2591 and_mask = TREE_OPERAND (exp, 1);
2592 exp = TREE_OPERAND (exp, 0);
2593 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2594 if (TREE_CODE (and_mask) != INTEGER_CST)
2599 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2600 punsignedp, pvolatilep, &alignment);
2601 if ((inner == exp && and_mask == 0)
2602 || *pbitsize < 0 || offset != 0)
2605 /* Compute the mask to access the bitfield. */
2606 unsigned_type = type_for_size (*pbitsize, 1);
2607 precision = TYPE_PRECISION (unsigned_type);
2609 mask = build_int_2 (~0, ~0);
2610 TREE_TYPE (mask) = unsigned_type;
2611 force_fit_type (mask, 0);
2612 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2613 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2615 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2617 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2618 convert (unsigned_type, and_mask), mask));
2621 *pand_mask = and_mask;
2625 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2629 all_ones_mask_p (mask, size)
2633 tree type = TREE_TYPE (mask);
2634 int precision = TYPE_PRECISION (type);
2637 tmask = build_int_2 (~0, ~0);
2638 TREE_TYPE (tmask) = signed_type (type);
2639 force_fit_type (tmask, 0);
2641 tree_int_cst_equal (mask,
2642 const_binop (RSHIFT_EXPR,
2643 const_binop (LSHIFT_EXPR, tmask,
2644 size_int (precision - size),
2646 size_int (precision - size), 0));
2649 /* Subroutine for fold_truthop: determine if an operand is simple enough
2650 to be evaluated unconditionally. */
2653 simple_operand_p (exp)
2656 /* Strip any conversions that don't change the machine mode. */
2657 while ((TREE_CODE (exp) == NOP_EXPR
2658 || TREE_CODE (exp) == CONVERT_EXPR)
2659 && (TYPE_MODE (TREE_TYPE (exp))
2660 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2661 exp = TREE_OPERAND (exp, 0);
2663 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2664 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2665 && ! TREE_ADDRESSABLE (exp)
2666 && ! TREE_THIS_VOLATILE (exp)
2667 && ! DECL_NONLOCAL (exp)
2668 /* Don't regard global variables as simple. They may be
2669 allocated in ways unknown to the compiler (shared memory,
2670 #pragma weak, etc). */
2671 && ! TREE_PUBLIC (exp)
2672 && ! DECL_EXTERNAL (exp)
2673 /* Loading a static variable is unduly expensive, but global
2674 registers aren't expensive. */
2675 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2678 /* The following functions are subroutines to fold_range_test and allow it to
2679 try to change a logical combination of comparisons into a range test.
2682 X == 2 && X == 3 && X == 4 && X == 5
2686 (unsigned) (X - 2) <= 3
2688 We describe each set of comparisons as being either inside or outside
2689 a range, using a variable named like IN_P, and then describe the
2690 range with a lower and upper bound. If one of the bounds is omitted,
2691 it represents either the highest or lowest value of the type.
2693 In the comments below, we represent a range by two numbers in brackets
2694 preceded by a "+" to designate being inside that range, or a "-" to
2695 designate being outside that range, so the condition can be inverted by
2696 flipping the prefix. An omitted bound is represented by a "-". For
2697 example, "- [-, 10]" means being outside the range starting at the lowest
2698 possible value and ending at 10, in other words, being greater than 10.
2699 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2702 We set up things so that the missing bounds are handled in a consistent
2703 manner so neither a missing bound nor "true" and "false" need to be
2704 handled using a special case. */
2706 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2707 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2708 and UPPER1_P are nonzero if the respective argument is an upper bound
2709 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2710 must be specified for a comparison. ARG1 will be converted to ARG0's
2711 type if both are specified. */
2714 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2715 enum tree_code code;
2718 int upper0_p, upper1_p;
2724 /* If neither arg represents infinity, do the normal operation.
2725 Else, if not a comparison, return infinity. Else handle the special
2726 comparison rules. Note that most of the cases below won't occur, but
2727 are handled for consistency. */
2729 if (arg0 != 0 && arg1 != 0)
2731 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2732 arg0, convert (TREE_TYPE (arg0), arg1)));
2734 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2737 if (TREE_CODE_CLASS (code) != '<')
2740 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2741 for neither. Then compute our result treating them as never equal
2742 and comparing bounds to non-bounds as above. */
2743 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2744 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2747 case EQ_EXPR: case NE_EXPR:
2748 result = (code == NE_EXPR);
2750 case LT_EXPR: case LE_EXPR:
2751 result = sgn0 < sgn1;
2753 case GT_EXPR: case GE_EXPR:
2754 result = sgn0 > sgn1;
2760 return convert (type, result ? integer_one_node : integer_zero_node);
2763 /* Given EXP, a logical expression, set the range it is testing into
2764 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2765 actually being tested. *PLOW and *PHIGH will have be made the same type
2766 as the returned expression. If EXP is not a comparison, we will most
2767 likely not be returning a useful value and range. */
2770 make_range (exp, pin_p, plow, phigh)
2775 enum tree_code code;
2776 tree arg0, arg1, type;
2778 tree low, high, n_low, n_high;
2780 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2781 and see if we can refine the range. Some of the cases below may not
2782 happen, but it doesn't seem worth worrying about this. We "continue"
2783 the outer loop when we've changed something; otherwise we "break"
2784 the switch, which will "break" the while. */
2786 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2790 code = TREE_CODE (exp);
2791 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2792 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2793 || TREE_CODE_CLASS (code) == '2')
2794 type = TREE_TYPE (arg0);
2798 case TRUTH_NOT_EXPR:
2799 in_p = ! in_p, exp = arg0;
2802 case EQ_EXPR: case NE_EXPR:
2803 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2804 /* We can only do something if the range is testing for zero
2805 and if the second operand is an integer constant. Note that
2806 saying something is "in" the range we make is done by
2807 complementing IN_P since it will set in the initial case of
2808 being not equal to zero; "out" is leaving it alone. */
2809 if (low == 0 || high == 0
2810 || ! integer_zerop (low) || ! integer_zerop (high)
2811 || TREE_CODE (arg1) != INTEGER_CST)
2816 case NE_EXPR: /* - [c, c] */
2819 case EQ_EXPR: /* + [c, c] */
2820 in_p = ! in_p, low = high = arg1;
2822 case GT_EXPR: /* - [-, c] */
2823 low = 0, high = arg1;
2825 case GE_EXPR: /* + [c, -] */
2826 in_p = ! in_p, low = arg1, high = 0;
2828 case LT_EXPR: /* - [c, -] */
2829 low = arg1, high = 0;
2831 case LE_EXPR: /* + [-, c] */
2832 in_p = ! in_p, low = 0, high = arg1;
2840 /* If this is an unsigned comparison, we also know that EXP is
2841 greater than or equal to zero. We base the range tests we make
2842 on that fact, so we record it here so we can parse existing
2844 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2846 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2847 1, convert (type, integer_zero_node),
2851 in_p = n_in_p, low = n_low, high = n_high;
2853 /* If the high bound is missing, reverse the range so it
2854 goes from zero to the low bound minus 1. */
2858 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2859 integer_one_node, 0);
2860 low = convert (type, integer_zero_node);
2866 /* (-x) IN [a,b] -> x in [-b, -a] */
2867 n_low = range_binop (MINUS_EXPR, type,
2868 convert (type, integer_zero_node), 0, high, 1);
2869 n_high = range_binop (MINUS_EXPR, type,
2870 convert (type, integer_zero_node), 0, low, 0);
2871 low = n_low, high = n_high;
2877 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2878 convert (type, integer_one_node));
2881 case PLUS_EXPR: case MINUS_EXPR:
2882 if (TREE_CODE (arg1) != INTEGER_CST)
2885 /* If EXP is signed, any overflow in the computation is undefined,
2886 so we don't worry about it so long as our computations on
2887 the bounds don't overflow. For unsigned, overflow is defined
2888 and this is exactly the right thing. */
2889 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2890 type, low, 0, arg1, 0);
2891 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2892 type, high, 1, arg1, 0);
2893 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2894 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2897 /* Check for an unsigned range which has wrapped around the maximum
2898 value thus making n_high < n_low, and normalize it. */
2899 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2901 low = range_binop (PLUS_EXPR, type, n_high, 0,
2902 integer_one_node, 0);
2903 high = range_binop (MINUS_EXPR, type, n_low, 0,
2904 integer_one_node, 0);
2908 low = n_low, high = n_high;
2913 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2914 if (! INTEGRAL_TYPE_P (type)
2915 || (low != 0 && ! int_fits_type_p (low, type))
2916 || (high != 0 && ! int_fits_type_p (high, type)))
2919 n_low = low, n_high = high;
2922 n_low = convert (type, n_low);
2925 n_high = convert (type, n_high);
2927 /* If we're converting from an unsigned to a signed type,
2928 we will be doing the comparison as unsigned. The tests above
2929 have already verified that LOW and HIGH are both positive.
2931 So we have to make sure that the original unsigned value will
2932 be interpreted as positive. */
2933 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
2935 tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
2938 /* A range without an upper bound is, naturally, unbounded.
2939 Since convert would have cropped a very large value, use
2940 the max value for the destination type. */
2942 high_positive = TYPE_MAX_VALUE (equiv_type);
2945 high_positive = TYPE_MAX_VALUE (type);
2949 high_positive = fold (build (RSHIFT_EXPR, type,
2950 convert (type, high_positive),
2951 convert (type, integer_one_node)));
2953 /* If the low bound is specified, "and" the range with the
2954 range for which the original unsigned value will be
2958 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2960 1, convert (type, integer_zero_node),
2964 in_p = (n_in_p == in_p);
2968 /* Otherwise, "or" the range with the range of the input
2969 that will be interpreted as negative. */
2970 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2972 1, convert (type, integer_zero_node),
2976 in_p = (in_p != n_in_p);
2981 low = n_low, high = n_high;
2991 /* If EXP is a constant, we can evaluate whether this is true or false. */
2992 if (TREE_CODE (exp) == INTEGER_CST)
2994 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2996 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3002 *pin_p = in_p, *plow = low, *phigh = high;
3006 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3007 type, TYPE, return an expression to test if EXP is in (or out of, depending
3008 on IN_P) the range. */
3011 build_range_check (type, exp, in_p, low, high)
3017 tree etype = TREE_TYPE (exp);
3021 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3022 return invert_truthvalue (value);
3024 else if (low == 0 && high == 0)
3025 return convert (type, integer_one_node);
3028 return fold (build (LE_EXPR, type, exp, high));
3031 return fold (build (GE_EXPR, type, exp, low));
3033 else if (operand_equal_p (low, high, 0))
3034 return fold (build (EQ_EXPR, type, exp, low));
3036 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
3037 return build_range_check (type, exp, 1, 0, high);
3039 else if (integer_zerop (low))
3041 utype = unsigned_type (etype);
3042 return build_range_check (type, convert (utype, exp), 1, 0,
3043 convert (utype, high));
3046 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3047 && ! TREE_OVERFLOW (value))
3048 return build_range_check (type,
3049 fold (build (MINUS_EXPR, etype, exp, low)),
3050 1, convert (etype, integer_zero_node), value);
3055 /* Given two ranges, see if we can merge them into one. Return 1 if we
3056 can, 0 if we can't. Set the output range into the specified parameters. */
3059 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3063 tree low0, high0, low1, high1;
3071 int lowequal = ((low0 == 0 && low1 == 0)
3072 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3073 low0, 0, low1, 0)));
3074 int highequal = ((high0 == 0 && high1 == 0)
3075 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3076 high0, 1, high1, 1)));
3078 /* Make range 0 be the range that starts first, or ends last if they
3079 start at the same value. Swap them if it isn't. */
3080 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3083 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3084 high1, 1, high0, 1))))
3086 temp = in0_p, in0_p = in1_p, in1_p = temp;
3087 tem = low0, low0 = low1, low1 = tem;
3088 tem = high0, high0 = high1, high1 = tem;
3091 /* Now flag two cases, whether the ranges are disjoint or whether the
3092 second range is totally subsumed in the first. Note that the tests
3093 below are simplified by the ones above. */
3094 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3095 high0, 1, low1, 0));
3096 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3097 high1, 1, high0, 1));
3099 /* We now have four cases, depending on whether we are including or
3100 excluding the two ranges. */
3103 /* If they don't overlap, the result is false. If the second range
3104 is a subset it is the result. Otherwise, the range is from the start
3105 of the second to the end of the first. */
3107 in_p = 0, low = high = 0;
3109 in_p = 1, low = low1, high = high1;
3111 in_p = 1, low = low1, high = high0;
3114 else if (in0_p && ! in1_p)
3116 /* If they don't overlap, the result is the first range. If they are
3117 equal, the result is false. If the second range is a subset of the
3118 first, and the ranges begin at the same place, we go from just after
3119 the end of the first range to the end of the second. If the second
3120 range is not a subset of the first, or if it is a subset and both
3121 ranges end at the same place, the range starts at the start of the
3122 first range and ends just before the second range.
3123 Otherwise, we can't describe this as a single range. */
3125 in_p = 1, low = low0, high = high0;
3126 else if (lowequal && highequal)
3127 in_p = 0, low = high = 0;
3128 else if (subset && lowequal)
3130 in_p = 1, high = high0;
3131 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3132 integer_one_node, 0);
3134 else if (! subset || highequal)
3136 in_p = 1, low = low0;
3137 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3138 integer_one_node, 0);
3144 else if (! in0_p && in1_p)
3146 /* If they don't overlap, the result is the second range. If the second
3147 is a subset of the first, the result is false. Otherwise,
3148 the range starts just after the first range and ends at the
3149 end of the second. */
3151 in_p = 1, low = low1, high = high1;
3153 in_p = 0, low = high = 0;
3156 in_p = 1, high = high1;
3157 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3158 integer_one_node, 0);
3164 /* The case where we are excluding both ranges. Here the complex case
3165 is if they don't overlap. In that case, the only time we have a
3166 range is if they are adjacent. If the second is a subset of the
3167 first, the result is the first. Otherwise, the range to exclude
3168 starts at the beginning of the first range and ends at the end of the
3172 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3173 range_binop (PLUS_EXPR, NULL_TREE,
3175 integer_one_node, 1),
3177 in_p = 0, low = low0, high = high1;
3182 in_p = 0, low = low0, high = high0;
3184 in_p = 0, low = low0, high = high1;
3187 *pin_p = in_p, *plow = low, *phigh = high;
3191 /* EXP is some logical combination of boolean tests. See if we can
3192 merge it into some range test. Return the new tree if so. */
3195 fold_range_test (exp)
3198 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3199 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3200 int in0_p, in1_p, in_p;
3201 tree low0, low1, low, high0, high1, high;
3202 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3203 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3206 /* If this is an OR operation, invert both sides; we will invert
3207 again at the end. */
3209 in0_p = ! in0_p, in1_p = ! in1_p;
3211 /* If both expressions are the same, if we can merge the ranges, and we
3212 can build the range test, return it or it inverted. If one of the
3213 ranges is always true or always false, consider it to be the same
3214 expression as the other. */
3215 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3216 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3218 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3220 : rhs != 0 ? rhs : integer_zero_node,
3222 return or_op ? invert_truthvalue (tem) : tem;
3224 /* On machines where the branch cost is expensive, if this is a
3225 short-circuited branch and the underlying object on both sides
3226 is the same, make a non-short-circuit operation. */
3227 else if (BRANCH_COST >= 2
3228 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3229 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3230 && operand_equal_p (lhs, rhs, 0))
3232 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3233 unless we are at top level, in which case we can't do this. */
3234 if (simple_operand_p (lhs))
3235 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3236 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3237 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3238 TREE_OPERAND (exp, 1));
3240 else if (current_function_decl != 0)
3242 tree common = save_expr (lhs);
3244 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3245 or_op ? ! in0_p : in0_p,
3247 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3248 or_op ? ! in1_p : in1_p,
3250 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3251 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3252 TREE_TYPE (exp), lhs, rhs);
3259 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3260 bit value. Arrange things so the extra bits will be set to zero if and
3261 only if C is signed-extended to its full width. If MASK is nonzero,
3262 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3265 unextend (c, p, unsignedp, mask)
3271 tree type = TREE_TYPE (c);
3272 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3275 if (p == modesize || unsignedp)
3278 /* We work by getting just the sign bit into the low-order bit, then
3279 into the high-order bit, then sign-extend. We then XOR that value
3281 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3282 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3284 /* We must use a signed type in order to get an arithmetic right shift.
3285 However, we must also avoid introducing accidental overflows, so that
3286 a subsequent call to integer_zerop will work. Hence we must
3287 do the type conversion here. At this point, the constant is either
3288 zero or one, and the conversion to a signed type can never overflow.
3289 We could get an overflow if this conversion is done anywhere else. */
3290 if (TREE_UNSIGNED (type))
3291 temp = convert (signed_type (type), temp);
3293 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3294 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3296 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3297 /* If necessary, convert the type back to match the type of C. */
3298 if (TREE_UNSIGNED (type))
3299 temp = convert (type, temp);
3301 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3304 /* Find ways of folding logical expressions of LHS and RHS:
3305 Try to merge two comparisons to the same innermost item.
3306 Look for range tests like "ch >= '0' && ch <= '9'".
3307 Look for combinations of simple terms on machines with expensive branches
3308 and evaluate the RHS unconditionally.
3310 For example, if we have p->a == 2 && p->b == 4 and we can make an
3311 object large enough to span both A and B, we can do this with a comparison
3312 against the object ANDed with the a mask.
3314 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3315 operations to do this with one comparison.
3317 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3318 function and the one above.
3320 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3321 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3323 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3326 We return the simplified tree or 0 if no optimization is possible. */
3329 fold_truthop (code, truth_type, lhs, rhs)
3330 enum tree_code code;
3331 tree truth_type, lhs, rhs;
3333 /* If this is the "or" of two comparisons, we can do something if we
3334 the comparisons are NE_EXPR. If this is the "and", we can do something
3335 if the comparisons are EQ_EXPR. I.e.,
3336 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3338 WANTED_CODE is this operation code. For single bit fields, we can
3339 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3340 comparison for one-bit fields. */
3342 enum tree_code wanted_code;
3343 enum tree_code lcode, rcode;
3344 tree ll_arg, lr_arg, rl_arg, rr_arg;
3345 tree ll_inner, lr_inner, rl_inner, rr_inner;
3346 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3347 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3348 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3349 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3350 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3351 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3352 enum machine_mode lnmode, rnmode;
3353 tree ll_mask, lr_mask, rl_mask, rr_mask;
3354 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3355 tree l_const, r_const;
3357 int first_bit, end_bit;
3360 /* Start by getting the comparison codes. Fail if anything is volatile.
3361 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3362 it were surrounded with a NE_EXPR. */
3364 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3367 lcode = TREE_CODE (lhs);
3368 rcode = TREE_CODE (rhs);
3370 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3371 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3373 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3374 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3376 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3379 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3380 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3382 ll_arg = TREE_OPERAND (lhs, 0);
3383 lr_arg = TREE_OPERAND (lhs, 1);
3384 rl_arg = TREE_OPERAND (rhs, 0);
3385 rr_arg = TREE_OPERAND (rhs, 1);
3387 /* If the RHS can be evaluated unconditionally and its operands are
3388 simple, it wins to evaluate the RHS unconditionally on machines
3389 with expensive branches. In this case, this isn't a comparison
3390 that can be merged. */
3392 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3393 are with zero (tmw). */
3395 if (BRANCH_COST >= 2
3396 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3397 && simple_operand_p (rl_arg)
3398 && simple_operand_p (rr_arg))
3399 return build (code, truth_type, lhs, rhs);
3401 /* See if the comparisons can be merged. Then get all the parameters for
3404 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3405 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3409 ll_inner = decode_field_reference (ll_arg,
3410 &ll_bitsize, &ll_bitpos, &ll_mode,
3411 &ll_unsignedp, &volatilep, &ll_mask,
3413 lr_inner = decode_field_reference (lr_arg,
3414 &lr_bitsize, &lr_bitpos, &lr_mode,
3415 &lr_unsignedp, &volatilep, &lr_mask,
3417 rl_inner = decode_field_reference (rl_arg,
3418 &rl_bitsize, &rl_bitpos, &rl_mode,
3419 &rl_unsignedp, &volatilep, &rl_mask,
3421 rr_inner = decode_field_reference (rr_arg,
3422 &rr_bitsize, &rr_bitpos, &rr_mode,
3423 &rr_unsignedp, &volatilep, &rr_mask,
3426 /* It must be true that the inner operation on the lhs of each
3427 comparison must be the same if we are to be able to do anything.
3428 Then see if we have constants. If not, the same must be true for
3430 if (volatilep || ll_inner == 0 || rl_inner == 0
3431 || ! operand_equal_p (ll_inner, rl_inner, 0))
3434 if (TREE_CODE (lr_arg) == INTEGER_CST
3435 && TREE_CODE (rr_arg) == INTEGER_CST)
3436 l_const = lr_arg, r_const = rr_arg;
3437 else if (lr_inner == 0 || rr_inner == 0
3438 || ! operand_equal_p (lr_inner, rr_inner, 0))
3441 l_const = r_const = 0;
3443 /* If either comparison code is not correct for our logical operation,
3444 fail. However, we can convert a one-bit comparison against zero into
3445 the opposite comparison against that bit being set in the field. */
3447 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3448 if (lcode != wanted_code)
3450 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3452 if (ll_unsignedp || tree_log2 (ll_mask) + 1 < ll_bitsize)
3455 /* Since ll_arg is a single bit bit mask, we can sign extend
3456 it appropriately with a NEGATE_EXPR.
3457 l_const is made a signed value here, but since for l_const != NULL
3458 lr_unsignedp is not used, we don't need to clear the latter. */
3459 l_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (ll_arg),
3460 convert (TREE_TYPE (ll_arg), ll_mask)));
3466 if (rcode != wanted_code)
3468 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3470 if (rl_unsignedp || tree_log2 (rl_mask) + 1 < rl_bitsize)
3473 /* This is analogous to the code for l_const above. */
3474 r_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (rl_arg),
3475 convert (TREE_TYPE (rl_arg), rl_mask)));
3481 /* See if we can find a mode that contains both fields being compared on
3482 the left. If we can't, fail. Otherwise, update all constants and masks
3483 to be relative to a field of that size. */
3484 first_bit = MIN (ll_bitpos, rl_bitpos);
3485 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3486 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3487 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3489 if (lnmode == VOIDmode)
3492 lnbitsize = GET_MODE_BITSIZE (lnmode);
3493 lnbitpos = first_bit & ~ (lnbitsize - 1);
3494 type = type_for_size (lnbitsize, 1);
3495 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3497 if (BYTES_BIG_ENDIAN)
3499 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3500 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3503 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3504 size_int (xll_bitpos), 0);
3505 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3506 size_int (xrl_bitpos), 0);
3510 l_const = convert (type, l_const);
3511 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3512 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3513 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3514 fold (build1 (BIT_NOT_EXPR,
3518 warning ("comparison is always %s",
3519 wanted_code == NE_EXPR ? "one" : "zero");
3521 return convert (truth_type,
3522 wanted_code == NE_EXPR
3523 ? integer_one_node : integer_zero_node);
3528 r_const = convert (type, r_const);
3529 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3530 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3531 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3532 fold (build1 (BIT_NOT_EXPR,
3536 warning ("comparison is always %s",
3537 wanted_code == NE_EXPR ? "one" : "zero");
3539 return convert (truth_type,
3540 wanted_code == NE_EXPR
3541 ? integer_one_node : integer_zero_node);
3545 /* If the right sides are not constant, do the same for it. Also,
3546 disallow this optimization if a size or signedness mismatch occurs
3547 between the left and right sides. */
3550 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3551 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3552 /* Make sure the two fields on the right
3553 correspond to the left without being swapped. */
3554 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3557 first_bit = MIN (lr_bitpos, rr_bitpos);
3558 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3559 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3560 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3562 if (rnmode == VOIDmode)
3565 rnbitsize = GET_MODE_BITSIZE (rnmode);
3566 rnbitpos = first_bit & ~ (rnbitsize - 1);
3567 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3569 if (BYTES_BIG_ENDIAN)
3571 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3572 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3575 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3576 size_int (xlr_bitpos), 0);
3577 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3578 size_int (xrr_bitpos), 0);
3580 /* Make a mask that corresponds to both fields being compared.
3581 Do this for both items being compared. If the masks agree,
3582 we can do this by masking both and comparing the masked
3584 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3585 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3586 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3588 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3589 ll_unsignedp || rl_unsignedp);
3590 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3591 lr_unsignedp || rr_unsignedp);
3592 if (! all_ones_mask_p (ll_mask, lnbitsize))
3594 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3595 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3597 return build (wanted_code, truth_type, lhs, rhs);
3600 /* There is still another way we can do something: If both pairs of
3601 fields being compared are adjacent, we may be able to make a wider
3602 field containing them both. */
3603 if ((ll_bitsize + ll_bitpos == rl_bitpos
3604 && lr_bitsize + lr_bitpos == rr_bitpos)
3605 || (ll_bitpos == rl_bitpos + rl_bitsize
3606 && lr_bitpos == rr_bitpos + rr_bitsize))
3607 return build (wanted_code, truth_type,
3608 make_bit_field_ref (ll_inner, type,
3609 ll_bitsize + rl_bitsize,
3610 MIN (ll_bitpos, rl_bitpos),
3612 make_bit_field_ref (lr_inner, type,
3613 lr_bitsize + rr_bitsize,
3614 MIN (lr_bitpos, rr_bitpos),
3620 /* Handle the case of comparisons with constants. If there is something in
3621 common between the masks, those bits of the constants must be the same.
3622 If not, the condition is always false. Test for this to avoid generating
3623 incorrect code below. */
3624 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3625 if (! integer_zerop (result)
3626 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3627 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3629 if (wanted_code == NE_EXPR)
3631 warning ("`or' of unmatched not-equal tests is always 1");
3632 return convert (truth_type, integer_one_node);
3636 warning ("`and' of mutually exclusive equal-tests is always zero");
3637 return convert (truth_type, integer_zero_node);
3641 /* Construct the expression we will return. First get the component
3642 reference we will make. Unless the mask is all ones the width of
3643 that field, perform the mask operation. Then compare with the
3645 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3646 ll_unsignedp || rl_unsignedp);
3648 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3649 if (! all_ones_mask_p (ll_mask, lnbitsize))
3650 result = build (BIT_AND_EXPR, type, result, ll_mask);
3652 return build (wanted_code, truth_type, result,
3653 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3656 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3657 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3658 that we may sometimes modify the tree. */
3661 strip_compound_expr (t, s)
3665 tree type = TREE_TYPE (t);
3666 enum tree_code code = TREE_CODE (t);
3668 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3669 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3670 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3671 return TREE_OPERAND (t, 1);
3673 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3674 don't bother handling any other types. */
3675 else if (code == COND_EXPR)
3677 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3678 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3679 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3681 else if (TREE_CODE_CLASS (code) == '1')
3682 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3683 else if (TREE_CODE_CLASS (code) == '<'
3684 || TREE_CODE_CLASS (code) == '2')
3686 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3687 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3693 /* Perform constant folding and related simplification of EXPR.
3694 The related simplifications include x*1 => x, x*0 => 0, etc.,
3695 and application of the associative law.
3696 NOP_EXPR conversions may be removed freely (as long as we
3697 are careful not to change the C type of the overall expression)
3698 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3699 but we can constant-fold them if they have constant operands. */
3705 register tree t = expr;
3706 tree t1 = NULL_TREE;
3708 tree type = TREE_TYPE (expr);
3709 register tree arg0, arg1;
3710 register enum tree_code code = TREE_CODE (t);
3714 /* WINS will be nonzero when the switch is done
3715 if all operands are constant. */
3719 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3720 Likewise for a SAVE_EXPR that's already been evaluated. */
3721 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3724 /* Return right away if already constant. */
3725 if (TREE_CONSTANT (t))
3727 if (code == CONST_DECL)
3728 return DECL_INITIAL (t);
3732 kind = TREE_CODE_CLASS (code);
3733 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3737 /* Special case for conversion ops that can have fixed point args. */
3738 arg0 = TREE_OPERAND (t, 0);
3740 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3742 STRIP_TYPE_NOPS (arg0);
3744 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3745 subop = TREE_REALPART (arg0);
3749 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3750 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3751 && TREE_CODE (subop) != REAL_CST
3752 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3754 /* Note that TREE_CONSTANT isn't enough:
3755 static var addresses are constant but we can't
3756 do arithmetic on them. */
3759 else if (kind == 'e' || kind == '<'
3760 || kind == '1' || kind == '2' || kind == 'r')
3762 register int len = tree_code_length[(int) code];
3764 for (i = 0; i < len; i++)
3766 tree op = TREE_OPERAND (t, i);
3770 continue; /* Valid for CALL_EXPR, at least. */
3772 if (kind == '<' || code == RSHIFT_EXPR)
3774 /* Signedness matters here. Perhaps we can refine this
3776 STRIP_TYPE_NOPS (op);
3780 /* Strip any conversions that don't change the mode. */
3784 if (TREE_CODE (op) == COMPLEX_CST)
3785 subop = TREE_REALPART (op);
3789 if (TREE_CODE (subop) != INTEGER_CST
3790 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3791 && TREE_CODE (subop) != REAL_CST
3792 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3794 /* Note that TREE_CONSTANT isn't enough:
3795 static var addresses are constant but we can't
3796 do arithmetic on them. */
3806 /* If this is a commutative operation, and ARG0 is a constant, move it
3807 to ARG1 to reduce the number of tests below. */
3808 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3809 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3810 || code == BIT_AND_EXPR)
3811 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3813 tem = arg0; arg0 = arg1; arg1 = tem;
3815 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3816 TREE_OPERAND (t, 1) = tem;
3819 /* Now WINS is set as described above,
3820 ARG0 is the first operand of EXPR,
3821 and ARG1 is the second operand (if it has more than one operand).
3823 First check for cases where an arithmetic operation is applied to a
3824 compound, conditional, or comparison operation. Push the arithmetic
3825 operation inside the compound or conditional to see if any folding
3826 can then be done. Convert comparison to conditional for this purpose.
3827 The also optimizes non-constant cases that used to be done in
3830 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3831 one of the operands is a comparison and the other is a comparison, a
3832 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3833 code below would make the expression more complex. Change it to a
3834 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3835 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3837 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3838 || code == EQ_EXPR || code == NE_EXPR)
3839 && ((truth_value_p (TREE_CODE (arg0))
3840 && (truth_value_p (TREE_CODE (arg1))
3841 || (TREE_CODE (arg1) == BIT_AND_EXPR
3842 && integer_onep (TREE_OPERAND (arg1, 1)))))
3843 || (truth_value_p (TREE_CODE (arg1))
3844 && (truth_value_p (TREE_CODE (arg0))
3845 || (TREE_CODE (arg0) == BIT_AND_EXPR
3846 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3848 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3849 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3853 if (code == EQ_EXPR)
3854 t = invert_truthvalue (t);
3859 if (TREE_CODE_CLASS (code) == '1')
3861 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3862 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3863 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3864 else if (TREE_CODE (arg0) == COND_EXPR)
3866 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3867 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3868 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3870 /* If this was a conversion, and all we did was to move into
3871 inside the COND_EXPR, bring it back out. But leave it if
3872 it is a conversion from integer to integer and the
3873 result precision is no wider than a word since such a
3874 conversion is cheap and may be optimized away by combine,
3875 while it couldn't if it were outside the COND_EXPR. Then return
3876 so we don't get into an infinite recursion loop taking the
3877 conversion out and then back in. */
3879 if ((code == NOP_EXPR || code == CONVERT_EXPR
3880 || code == NON_LVALUE_EXPR)
3881 && TREE_CODE (t) == COND_EXPR
3882 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3883 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3884 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3885 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3886 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3887 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3888 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3889 t = build1 (code, type,
3891 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3892 TREE_OPERAND (t, 0),
3893 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3894 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3897 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3898 return fold (build (COND_EXPR, type, arg0,
3899 fold (build1 (code, type, integer_one_node)),
3900 fold (build1 (code, type, integer_zero_node))));
3902 else if (TREE_CODE_CLASS (code) == '2'
3903 || TREE_CODE_CLASS (code) == '<')
3905 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3906 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3907 fold (build (code, type,
3908 arg0, TREE_OPERAND (arg1, 1))));
3909 else if ((TREE_CODE (arg1) == COND_EXPR
3910 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3911 && TREE_CODE_CLASS (code) != '<'))
3912 && (! TREE_SIDE_EFFECTS (arg0) || current_function_decl != 0))
3914 tree test, true_value, false_value;
3916 if (TREE_CODE (arg1) == COND_EXPR)
3918 test = TREE_OPERAND (arg1, 0);
3919 true_value = TREE_OPERAND (arg1, 1);
3920 false_value = TREE_OPERAND (arg1, 2);
3924 tree testtype = TREE_TYPE (arg1);
3926 true_value = convert (testtype, integer_one_node);
3927 false_value = convert (testtype, integer_zero_node);
3930 /* If ARG0 is complex we want to make sure we only evaluate
3931 it once. Though this is only required if it is volatile, it
3932 might be more efficient even if it is not. However, if we
3933 succeed in folding one part to a constant, we do not need
3934 to make this SAVE_EXPR. Since we do this optimization
3935 primarily to see if we do end up with constant and this
3936 SAVE_EXPR interferes with later optimizations, suppressing
3937 it when we can is important. */
3939 if (TREE_CODE (arg0) != SAVE_EXPR
3940 && ((TREE_CODE (arg0) != VAR_DECL
3941 && TREE_CODE (arg0) != PARM_DECL)
3942 || TREE_SIDE_EFFECTS (arg0)))
3944 tree lhs = fold (build (code, type, arg0, true_value));
3945 tree rhs = fold (build (code, type, arg0, false_value));
3947 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3948 return fold (build (COND_EXPR, type, test, lhs, rhs));
3950 if (current_function_decl != 0)
3951 arg0 = save_expr (arg0);
3954 test = fold (build (COND_EXPR, type, test,
3955 fold (build (code, type, arg0, true_value)),
3956 fold (build (code, type, arg0, false_value))));
3957 if (TREE_CODE (arg0) == SAVE_EXPR)
3958 return build (COMPOUND_EXPR, type,
3959 convert (void_type_node, arg0),
3960 strip_compound_expr (test, arg0));
3962 return convert (type, test);
3965 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3966 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3967 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3968 else if ((TREE_CODE (arg0) == COND_EXPR
3969 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3970 && TREE_CODE_CLASS (code) != '<'))
3971 && (! TREE_SIDE_EFFECTS (arg1) || current_function_decl != 0))
3973 tree test, true_value, false_value;
3975 if (TREE_CODE (arg0) == COND_EXPR)
3977 test = TREE_OPERAND (arg0, 0);
3978 true_value = TREE_OPERAND (arg0, 1);
3979 false_value = TREE_OPERAND (arg0, 2);
3983 tree testtype = TREE_TYPE (arg0);
3985 true_value = convert (testtype, integer_one_node);
3986 false_value = convert (testtype, integer_zero_node);
3989 if (TREE_CODE (arg1) != SAVE_EXPR
3990 && ((TREE_CODE (arg1) != VAR_DECL
3991 && TREE_CODE (arg1) != PARM_DECL)
3992 || TREE_SIDE_EFFECTS (arg1)))
3994 tree lhs = fold (build (code, type, true_value, arg1));
3995 tree rhs = fold (build (code, type, false_value, arg1));
3997 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
3998 || TREE_CONSTANT (arg1))
3999 return fold (build (COND_EXPR, type, test, lhs, rhs));
4001 if (current_function_decl != 0)
4002 arg1 = save_expr (arg1);
4005 test = fold (build (COND_EXPR, type, test,
4006 fold (build (code, type, true_value, arg1)),
4007 fold (build (code, type, false_value, arg1))));
4008 if (TREE_CODE (arg1) == SAVE_EXPR)
4009 return build (COMPOUND_EXPR, type,
4010 convert (void_type_node, arg1),
4011 strip_compound_expr (test, arg1));
4013 return convert (type, test);
4016 else if (TREE_CODE_CLASS (code) == '<'
4017 && TREE_CODE (arg0) == COMPOUND_EXPR)
4018 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4019 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4020 else if (TREE_CODE_CLASS (code) == '<'
4021 && TREE_CODE (arg1) == COMPOUND_EXPR)
4022 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4023 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4035 return fold (DECL_INITIAL (t));
4040 case FIX_TRUNC_EXPR:
4041 /* Other kinds of FIX are not handled properly by fold_convert. */
4043 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4044 return TREE_OPERAND (t, 0);
4046 /* Handle cases of two conversions in a row. */
4047 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4048 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4050 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4051 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4052 tree final_type = TREE_TYPE (t);
4053 int inside_int = INTEGRAL_TYPE_P (inside_type);
4054 int inside_ptr = POINTER_TYPE_P (inside_type);
4055 int inside_float = FLOAT_TYPE_P (inside_type);
4056 int inside_prec = TYPE_PRECISION (inside_type);
4057 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4058 int inter_int = INTEGRAL_TYPE_P (inter_type);
4059 int inter_ptr = POINTER_TYPE_P (inter_type);
4060 int inter_float = FLOAT_TYPE_P (inter_type);
4061 int inter_prec = TYPE_PRECISION (inter_type);
4062 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4063 int final_int = INTEGRAL_TYPE_P (final_type);
4064 int final_ptr = POINTER_TYPE_P (final_type);
4065 int final_float = FLOAT_TYPE_P (final_type);
4066 int final_prec = TYPE_PRECISION (final_type);
4067 int final_unsignedp = TREE_UNSIGNED (final_type);
4069 /* In addition to the cases of two conversions in a row
4070 handled below, if we are converting something to its own
4071 type via an object of identical or wider precision, neither
4072 conversion is needed. */
4073 if (inside_type == final_type
4074 && ((inter_int && final_int) || (inter_float && final_float))
4075 && inter_prec >= final_prec)
4076 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
4078 /* Likewise, if the intermediate and final types are either both
4079 float or both integer, we don't need the middle conversion if
4080 it is wider than the final type and doesn't change the signedness
4081 (for integers). Avoid this if the final type is a pointer
4082 since then we sometimes need the inner conversion. Likewise if
4083 the outer has a precision not equal to the size of its mode. */
4084 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4085 || (inter_float && inside_float))
4086 && inter_prec >= inside_prec
4087 && (inter_float || inter_unsignedp == inside_unsignedp)
4088 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4089 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4091 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4093 /* Two conversions in a row are not needed unless:
4094 - some conversion is floating-point (overstrict for now), or
4095 - the intermediate type is narrower than both initial and
4097 - the intermediate type and innermost type differ in signedness,
4098 and the outermost type is wider than the intermediate, or
4099 - the initial type is a pointer type and the precisions of the
4100 intermediate and final types differ, or
4101 - the final type is a pointer type and the precisions of the
4102 initial and intermediate types differ. */
4103 if (! inside_float && ! inter_float && ! final_float
4104 && (inter_prec > inside_prec || inter_prec > final_prec)
4105 && ! (inside_int && inter_int
4106 && inter_unsignedp != inside_unsignedp
4107 && inter_prec < final_prec)
4108 && ((inter_unsignedp && inter_prec > inside_prec)
4109 == (final_unsignedp && final_prec > inter_prec))
4110 && ! (inside_ptr && inter_prec != final_prec)
4111 && ! (final_ptr && inside_prec != inter_prec)
4112 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4113 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4115 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4118 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4119 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4120 /* Detect assigning a bitfield. */
4121 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4122 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4124 /* Don't leave an assignment inside a conversion
4125 unless assigning a bitfield. */
4126 tree prev = TREE_OPERAND (t, 0);
4127 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4128 /* First do the assignment, then return converted constant. */
4129 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4135 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4138 return fold_convert (t, arg0);
4140 #if 0 /* This loses on &"foo"[0]. */
4145 /* Fold an expression like: "foo"[2] */
4146 if (TREE_CODE (arg0) == STRING_CST
4147 && TREE_CODE (arg1) == INTEGER_CST
4148 && !TREE_INT_CST_HIGH (arg1)
4149 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
4151 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
4152 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
4153 force_fit_type (t, 0);
4160 if (TREE_CODE (arg0) == CONSTRUCTOR)
4162 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4169 TREE_CONSTANT (t) = wins;
4175 if (TREE_CODE (arg0) == INTEGER_CST)
4177 HOST_WIDE_INT low, high;
4178 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4179 TREE_INT_CST_HIGH (arg0),
4181 t = build_int_2 (low, high);
4182 TREE_TYPE (t) = type;
4184 = (TREE_OVERFLOW (arg0)
4185 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4186 TREE_CONSTANT_OVERFLOW (t)
4187 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4189 else if (TREE_CODE (arg0) == REAL_CST)
4190 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4192 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4193 return TREE_OPERAND (arg0, 0);
4195 /* Convert - (a - b) to (b - a) for non-floating-point. */
4196 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4197 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4198 TREE_OPERAND (arg0, 0));
4205 if (TREE_CODE (arg0) == INTEGER_CST)
4207 if (! TREE_UNSIGNED (type)
4208 && TREE_INT_CST_HIGH (arg0) < 0)
4210 HOST_WIDE_INT low, high;
4211 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4212 TREE_INT_CST_HIGH (arg0),
4214 t = build_int_2 (low, high);
4215 TREE_TYPE (t) = type;
4217 = (TREE_OVERFLOW (arg0)
4218 | force_fit_type (t, overflow));
4219 TREE_CONSTANT_OVERFLOW (t)
4220 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4223 else if (TREE_CODE (arg0) == REAL_CST)
4225 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4226 t = build_real (type,
4227 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4230 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4231 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4235 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4237 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4238 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4239 TREE_OPERAND (arg0, 0),
4240 fold (build1 (NEGATE_EXPR,
4241 TREE_TYPE (TREE_TYPE (arg0)),
4242 TREE_OPERAND (arg0, 1))));
4243 else if (TREE_CODE (arg0) == COMPLEX_CST)
4244 return build_complex (type, TREE_OPERAND (arg0, 0),
4245 fold (build1 (NEGATE_EXPR,
4246 TREE_TYPE (TREE_TYPE (arg0)),
4247 TREE_OPERAND (arg0, 1))));
4248 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4249 return fold (build (TREE_CODE (arg0), type,
4250 fold (build1 (CONJ_EXPR, type,
4251 TREE_OPERAND (arg0, 0))),
4252 fold (build1 (CONJ_EXPR,
4253 type, TREE_OPERAND (arg0, 1)))));
4254 else if (TREE_CODE (arg0) == CONJ_EXPR)
4255 return TREE_OPERAND (arg0, 0);
4261 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4262 ~ TREE_INT_CST_HIGH (arg0));
4263 TREE_TYPE (t) = type;
4264 force_fit_type (t, 0);
4265 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4266 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4268 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4269 return TREE_OPERAND (arg0, 0);
4273 /* A + (-B) -> A - B */
4274 if (TREE_CODE (arg1) == NEGATE_EXPR)
4275 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4276 else if (! FLOAT_TYPE_P (type))
4278 if (integer_zerop (arg1))
4279 return non_lvalue (convert (type, arg0));
4281 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4282 with a constant, and the two constants have no bits in common,
4283 we should treat this as a BIT_IOR_EXPR since this may produce more
4285 if (TREE_CODE (arg0) == BIT_AND_EXPR
4286 && TREE_CODE (arg1) == BIT_AND_EXPR
4287 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4288 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4289 && integer_zerop (const_binop (BIT_AND_EXPR,
4290 TREE_OPERAND (arg0, 1),
4291 TREE_OPERAND (arg1, 1), 0)))
4293 code = BIT_IOR_EXPR;
4297 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4298 about the case where C is a constant, just try one of the
4299 four possibilities. */
4301 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4302 && operand_equal_p (TREE_OPERAND (arg0, 1),
4303 TREE_OPERAND (arg1, 1), 0))
4304 return fold (build (MULT_EXPR, type,
4305 fold (build (PLUS_EXPR, type,
4306 TREE_OPERAND (arg0, 0),
4307 TREE_OPERAND (arg1, 0))),
4308 TREE_OPERAND (arg0, 1)));
4310 /* In IEEE floating point, x+0 may not equal x. */
4311 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4313 && real_zerop (arg1))
4314 return non_lvalue (convert (type, arg0));
4316 /* In most languages, can't associate operations on floats
4317 through parentheses. Rather than remember where the parentheses
4318 were, we don't associate floats at all. It shouldn't matter much.
4319 However, associating multiplications is only very slightly
4320 inaccurate, so do that if -ffast-math is specified. */
4321 if (FLOAT_TYPE_P (type)
4322 && ! (flag_fast_math && code == MULT_EXPR))
4325 /* The varsign == -1 cases happen only for addition and subtraction.
4326 It says that the arg that was split was really CON minus VAR.
4327 The rest of the code applies to all associative operations. */
4333 if (split_tree (arg0, code, &var, &con, &varsign))
4337 /* EXPR is (CON-VAR) +- ARG1. */
4338 /* If it is + and VAR==ARG1, return just CONST. */
4339 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4340 return convert (TREE_TYPE (t), con);
4342 /* If ARG0 is a constant, don't change things around;
4343 instead keep all the constant computations together. */
4345 if (TREE_CONSTANT (arg0))
4348 /* Otherwise return (CON +- ARG1) - VAR. */
4349 t = build (MINUS_EXPR, type,
4350 fold (build (code, type, con, arg1)), var);
4354 /* EXPR is (VAR+CON) +- ARG1. */
4355 /* If it is - and VAR==ARG1, return just CONST. */
4356 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4357 return convert (TREE_TYPE (t), con);
4359 /* If ARG0 is a constant, don't change things around;
4360 instead keep all the constant computations together. */
4362 if (TREE_CONSTANT (arg0))
4365 /* Otherwise return VAR +- (ARG1 +- CON). */
4366 tem = fold (build (code, type, arg1, con));
4367 t = build (code, type, var, tem);
4369 if (integer_zerop (tem)
4370 && (code == PLUS_EXPR || code == MINUS_EXPR))
4371 return convert (type, var);
4372 /* If we have x +/- (c - d) [c an explicit integer]
4373 change it to x -/+ (d - c) since if d is relocatable
4374 then the latter can be a single immediate insn
4375 and the former cannot. */
4376 if (TREE_CODE (tem) == MINUS_EXPR
4377 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4379 tree tem1 = TREE_OPERAND (tem, 1);
4380 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4381 TREE_OPERAND (tem, 0) = tem1;
4383 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4389 if (split_tree (arg1, code, &var, &con, &varsign))
4391 if (TREE_CONSTANT (arg1))
4396 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4398 /* EXPR is ARG0 +- (CON +- VAR). */
4399 if (TREE_CODE (t) == MINUS_EXPR
4400 && operand_equal_p (var, arg0, 0))
4402 /* If VAR and ARG0 cancel, return just CON or -CON. */
4403 if (code == PLUS_EXPR)
4404 return convert (TREE_TYPE (t), con);
4405 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4406 convert (TREE_TYPE (t), con)));
4409 t = build (TREE_CODE (t), type,
4410 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4412 if (integer_zerop (TREE_OPERAND (t, 0))
4413 && TREE_CODE (t) == PLUS_EXPR)
4414 return convert (TREE_TYPE (t), var);
4419 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4420 if (TREE_CODE (arg1) == REAL_CST)
4422 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4424 t1 = const_binop (code, arg0, arg1, 0);
4425 if (t1 != NULL_TREE)
4427 /* The return value should always have
4428 the same type as the original expression. */
4429 if (TREE_TYPE (t1) != TREE_TYPE (t))
4430 t1 = convert (TREE_TYPE (t), t1);
4437 if (! FLOAT_TYPE_P (type))
4439 if (! wins && integer_zerop (arg0))
4440 return build1 (NEGATE_EXPR, type, arg1);
4441 if (integer_zerop (arg1))
4442 return non_lvalue (convert (type, arg0));
4444 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4445 about the case where C is a constant, just try one of the
4446 four possibilities. */
4448 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4449 && operand_equal_p (TREE_OPERAND (arg0, 1),
4450 TREE_OPERAND (arg1, 1), 0))
4451 return fold (build (MULT_EXPR, type,
4452 fold (build (MINUS_EXPR, type,
4453 TREE_OPERAND (arg0, 0),
4454 TREE_OPERAND (arg1, 0))),
4455 TREE_OPERAND (arg0, 1)));
4457 /* Convert A - (-B) to A + B. */
4458 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4459 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4461 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4464 /* Except with IEEE floating point, 0-x equals -x. */
4465 if (! wins && real_zerop (arg0))
4466 return build1 (NEGATE_EXPR, type, arg1);
4467 /* Except with IEEE floating point, x-0 equals x. */
4468 if (real_zerop (arg1))
4469 return non_lvalue (convert (type, arg0));
4472 /* Fold &x - &x. This can happen from &x.foo - &x.
4473 This is unsafe for certain floats even in non-IEEE formats.
4474 In IEEE, it is unsafe because it does wrong for NaNs.
4475 Also note that operand_equal_p is always false if an operand
4478 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4479 && operand_equal_p (arg0, arg1, 0))
4480 return convert (type, integer_zero_node);
4485 if (! FLOAT_TYPE_P (type))
4487 if (integer_zerop (arg1))
4488 return omit_one_operand (type, arg1, arg0);
4489 if (integer_onep (arg1))
4490 return non_lvalue (convert (type, arg0));
4492 /* ((A / C) * C) is A if the division is an
4493 EXACT_DIV_EXPR. Since C is normally a constant,
4494 just check for one of the four possibilities. */
4496 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4497 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4498 return TREE_OPERAND (arg0, 0);
4500 /* (a * (1 << b)) is (a << b) */
4501 if (TREE_CODE (arg1) == LSHIFT_EXPR
4502 && integer_onep (TREE_OPERAND (arg1, 0)))
4503 return fold (build (LSHIFT_EXPR, type, arg0,
4504 TREE_OPERAND (arg1, 1)));
4505 if (TREE_CODE (arg0) == LSHIFT_EXPR
4506 && integer_onep (TREE_OPERAND (arg0, 0)))
4507 return fold (build (LSHIFT_EXPR, type, arg1,
4508 TREE_OPERAND (arg0, 1)));
4512 /* x*0 is 0, except for IEEE floating point. */
4513 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4515 && real_zerop (arg1))
4516 return omit_one_operand (type, arg1, arg0);
4517 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4518 However, ANSI says we can drop signals,
4519 so we can do this anyway. */
4520 if (real_onep (arg1))
4521 return non_lvalue (convert (type, arg0));
4523 if (! wins && real_twop (arg1) && current_function_decl != 0)
4525 tree arg = save_expr (arg0);
4526 return build (PLUS_EXPR, type, arg, arg);
4534 register enum tree_code code0, code1;
4536 if (integer_all_onesp (arg1))
4537 return omit_one_operand (type, arg1, arg0);
4538 if (integer_zerop (arg1))
4539 return non_lvalue (convert (type, arg0));
4540 t1 = distribute_bit_expr (code, type, arg0, arg1);
4541 if (t1 != NULL_TREE)
4544 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4545 is a rotate of A by C1 bits. */
4546 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4547 is a rotate of A by B bits. */
4549 code0 = TREE_CODE (arg0);
4550 code1 = TREE_CODE (arg1);
4551 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4552 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4553 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4554 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4556 register tree tree01, tree11;
4557 register enum tree_code code01, code11;
4559 tree01 = TREE_OPERAND (arg0, 1);
4560 tree11 = TREE_OPERAND (arg1, 1);
4561 code01 = TREE_CODE (tree01);
4562 code11 = TREE_CODE (tree11);
4563 if (code01 == INTEGER_CST
4564 && code11 == INTEGER_CST
4565 && TREE_INT_CST_HIGH (tree01) == 0
4566 && TREE_INT_CST_HIGH (tree11) == 0
4567 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4568 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4569 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4570 code0 == LSHIFT_EXPR ? tree01 : tree11);
4571 else if (code11 == MINUS_EXPR
4572 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4573 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4574 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4575 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4576 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4577 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4578 type, TREE_OPERAND (arg0, 0), tree01);
4579 else if (code01 == MINUS_EXPR
4580 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4581 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4582 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4583 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4584 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4585 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4586 type, TREE_OPERAND (arg0, 0), tree11);
4593 if (integer_zerop (arg1))
4594 return non_lvalue (convert (type, arg0));
4595 if (integer_all_onesp (arg1))
4596 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4601 if (integer_all_onesp (arg1))
4602 return non_lvalue (convert (type, arg0));
4603 if (integer_zerop (arg1))
4604 return omit_one_operand (type, arg1, arg0);
4605 t1 = distribute_bit_expr (code, type, arg0, arg1);
4606 if (t1 != NULL_TREE)
4608 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4609 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4610 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4612 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4613 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4614 && (~TREE_INT_CST_LOW (arg0)
4615 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4616 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4618 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4619 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4621 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4622 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4623 && (~TREE_INT_CST_LOW (arg1)
4624 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4625 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4629 case BIT_ANDTC_EXPR:
4630 if (integer_all_onesp (arg0))
4631 return non_lvalue (convert (type, arg1));
4632 if (integer_zerop (arg0))
4633 return omit_one_operand (type, arg0, arg1);
4634 if (TREE_CODE (arg1) == INTEGER_CST)
4636 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4637 code = BIT_AND_EXPR;
4643 /* In most cases, do nothing with a divide by zero. */
4644 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4645 #ifndef REAL_INFINITY
4646 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4649 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4651 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4652 However, ANSI says we can drop signals, so we can do this anyway. */
4653 if (real_onep (arg1))
4654 return non_lvalue (convert (type, arg0));
4656 /* If ARG1 is a constant, we can convert this to a multiply by the
4657 reciprocal. This does not have the same rounding properties,
4658 so only do this if -ffast-math. We can actually always safely
4659 do it if ARG1 is a power of two, but it's hard to tell if it is
4660 or not in a portable manner. */
4661 if (TREE_CODE (arg1) == REAL_CST)
4664 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4666 return fold (build (MULT_EXPR, type, arg0, tem));
4667 /* Find the reciprocal if optimizing and the result is exact. */
4671 r = TREE_REAL_CST (arg1);
4672 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4674 tem = build_real (type, r);
4675 return fold (build (MULT_EXPR, type, arg0, tem));
4681 case TRUNC_DIV_EXPR:
4682 case ROUND_DIV_EXPR:
4683 case FLOOR_DIV_EXPR:
4685 case EXACT_DIV_EXPR:
4686 if (integer_onep (arg1))
4687 return non_lvalue (convert (type, arg0));
4688 if (integer_zerop (arg1))
4691 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
4692 operation, EXACT_DIV_EXPR.
4694 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
4695 At one time others generated faster code, it's not clear if they do
4696 after the last round to changes to the DIV code in expmed.c. */
4697 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
4698 && multiple_of_p (type, arg0, arg1))
4699 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
4701 /* If we have ((a / C1) / C2) where both division are the same type, try
4702 to simplify. First see if C1 * C2 overflows or not. */
4703 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4704 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4708 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4709 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4711 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4712 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4714 /* If no overflow, divide by C1*C2. */
4715 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4719 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4720 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4721 expressions, which often appear in the offsets or sizes of
4722 objects with a varying size. Only deal with positive divisors
4723 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4725 Look for NOPs and SAVE_EXPRs inside. */
4727 if (TREE_CODE (arg1) == INTEGER_CST
4728 && tree_int_cst_sgn (arg1) >= 0)
4730 int have_save_expr = 0;
4731 tree c2 = integer_zero_node;
4734 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4735 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4739 /* Look inside the dividend and simplify using EXACT_DIV_EXPR
4741 if (TREE_CODE (xarg0) == MULT_EXPR
4742 && multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
4746 t = fold (build (MULT_EXPR, type,
4747 fold (build (EXACT_DIV_EXPR, type,
4748 TREE_OPERAND (xarg0, 0), arg1)),
4749 TREE_OPERAND (xarg0, 1)));
4756 if (TREE_CODE (xarg0) == MULT_EXPR
4757 && multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
4761 t = fold (build (MULT_EXPR, type,
4762 fold (build (EXACT_DIV_EXPR, type,
4763 TREE_OPERAND (xarg0, 1), arg1)),
4764 TREE_OPERAND (xarg0, 0)));
4770 if (TREE_CODE (xarg0) == PLUS_EXPR
4771 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4772 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4773 else if (TREE_CODE (xarg0) == MINUS_EXPR
4774 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4775 /* If we are doing this computation unsigned, the negate
4777 && ! TREE_UNSIGNED (type))
4779 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4780 xarg0 = TREE_OPERAND (xarg0, 0);
4783 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4784 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4788 if (TREE_CODE (xarg0) == MULT_EXPR
4789 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4790 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4791 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4792 TREE_OPERAND (xarg0, 1), arg1, 1))
4793 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4794 TREE_OPERAND (xarg0, 1), 1)))
4795 && (tree_int_cst_sgn (c2) >= 0
4796 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4799 tree outer_div = integer_one_node;
4800 tree c1 = TREE_OPERAND (xarg0, 1);
4803 /* If C3 > C1, set them equal and do a divide by
4804 C3/C1 at the end of the operation. */
4805 if (tree_int_cst_lt (c1, c3))
4806 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4808 /* The result is A * (C1/C3) + (C2/C3). */
4809 t = fold (build (PLUS_EXPR, type,
4810 fold (build (MULT_EXPR, type,
4811 TREE_OPERAND (xarg0, 0),
4812 const_binop (code, c1, c3, 1))),
4813 const_binop (code, c2, c3, 1)));
4815 if (! integer_onep (outer_div))
4816 t = fold (build (code, type, t, convert (type, outer_div)));
4828 case FLOOR_MOD_EXPR:
4829 case ROUND_MOD_EXPR:
4830 case TRUNC_MOD_EXPR:
4831 if (integer_onep (arg1))
4832 return omit_one_operand (type, integer_zero_node, arg0);
4833 if (integer_zerop (arg1))
4836 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4837 where C1 % C3 == 0. Handle similarly to the division case,
4838 but don't bother with SAVE_EXPRs. */
4840 if (TREE_CODE (arg1) == INTEGER_CST
4841 && ! integer_zerop (arg1))
4843 tree c2 = integer_zero_node;
4846 if (TREE_CODE (xarg0) == PLUS_EXPR
4847 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4848 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4849 else if (TREE_CODE (xarg0) == MINUS_EXPR
4850 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4851 && ! TREE_UNSIGNED (type))
4853 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4854 xarg0 = TREE_OPERAND (xarg0, 0);
4859 if (TREE_CODE (xarg0) == MULT_EXPR
4860 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4861 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4862 TREE_OPERAND (xarg0, 1),
4864 && tree_int_cst_sgn (c2) >= 0)
4865 /* The result is (C2%C3). */
4866 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4867 TREE_OPERAND (xarg0, 0));
4876 if (integer_zerop (arg1))
4877 return non_lvalue (convert (type, arg0));
4878 /* Since negative shift count is not well-defined,
4879 don't try to compute it in the compiler. */
4880 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4882 /* Rewrite an LROTATE_EXPR by a constant into an
4883 RROTATE_EXPR by a new constant. */
4884 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4886 TREE_SET_CODE (t, RROTATE_EXPR);
4887 code = RROTATE_EXPR;
4888 TREE_OPERAND (t, 1) = arg1
4891 convert (TREE_TYPE (arg1),
4892 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4894 if (tree_int_cst_sgn (arg1) < 0)
4898 /* If we have a rotate of a bit operation with the rotate count and
4899 the second operand of the bit operation both constant,
4900 permute the two operations. */
4901 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4902 && (TREE_CODE (arg0) == BIT_AND_EXPR
4903 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4904 || TREE_CODE (arg0) == BIT_IOR_EXPR
4905 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4906 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4907 return fold (build (TREE_CODE (arg0), type,
4908 fold (build (code, type,
4909 TREE_OPERAND (arg0, 0), arg1)),
4910 fold (build (code, type,
4911 TREE_OPERAND (arg0, 1), arg1))));
4913 /* Two consecutive rotates adding up to the width of the mode can
4915 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4916 && TREE_CODE (arg0) == RROTATE_EXPR
4917 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4918 && TREE_INT_CST_HIGH (arg1) == 0
4919 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4920 && ((TREE_INT_CST_LOW (arg1)
4921 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4922 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4923 return TREE_OPERAND (arg0, 0);
4928 if (operand_equal_p (arg0, arg1, 0))
4930 if (INTEGRAL_TYPE_P (type)
4931 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4932 return omit_one_operand (type, arg1, arg0);
4936 if (operand_equal_p (arg0, arg1, 0))
4938 if (INTEGRAL_TYPE_P (type)
4939 && TYPE_MAX_VALUE (type)
4940 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4941 return omit_one_operand (type, arg1, arg0);
4944 case TRUTH_NOT_EXPR:
4945 /* Note that the operand of this must be an int
4946 and its values must be 0 or 1.
4947 ("true" is a fixed value perhaps depending on the language,
4948 but we don't handle values other than 1 correctly yet.) */
4949 tem = invert_truthvalue (arg0);
4950 /* Avoid infinite recursion. */
4951 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4953 return convert (type, tem);
4955 case TRUTH_ANDIF_EXPR:
4956 /* Note that the operands of this must be ints
4957 and their values must be 0 or 1.
4958 ("true" is a fixed value perhaps depending on the language.) */
4959 /* If first arg is constant zero, return it. */
4960 if (integer_zerop (arg0))
4962 case TRUTH_AND_EXPR:
4963 /* If either arg is constant true, drop it. */
4964 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4965 return non_lvalue (arg1);
4966 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4967 return non_lvalue (arg0);
4968 /* If second arg is constant zero, result is zero, but first arg
4969 must be evaluated. */
4970 if (integer_zerop (arg1))
4971 return omit_one_operand (type, arg1, arg0);
4972 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4973 case will be handled here. */
4974 if (integer_zerop (arg0))
4975 return omit_one_operand (type, arg0, arg1);
4978 /* We only do these simplifications if we are optimizing. */
4982 /* Check for things like (A || B) && (A || C). We can convert this
4983 to A || (B && C). Note that either operator can be any of the four
4984 truth and/or operations and the transformation will still be
4985 valid. Also note that we only care about order for the
4986 ANDIF and ORIF operators. If B contains side effects, this
4987 might change the truth-value of A. */
4988 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4989 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4990 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4991 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4992 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
4993 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
4995 tree a00 = TREE_OPERAND (arg0, 0);
4996 tree a01 = TREE_OPERAND (arg0, 1);
4997 tree a10 = TREE_OPERAND (arg1, 0);
4998 tree a11 = TREE_OPERAND (arg1, 1);
4999 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5000 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5001 && (code == TRUTH_AND_EXPR
5002 || code == TRUTH_OR_EXPR));
5004 if (operand_equal_p (a00, a10, 0))
5005 return fold (build (TREE_CODE (arg0), type, a00,
5006 fold (build (code, type, a01, a11))));
5007 else if (commutative && operand_equal_p (a00, a11, 0))
5008 return fold (build (TREE_CODE (arg0), type, a00,
5009 fold (build (code, type, a01, a10))));
5010 else if (commutative && operand_equal_p (a01, a10, 0))
5011 return fold (build (TREE_CODE (arg0), type, a01,
5012 fold (build (code, type, a00, a11))));
5014 /* This case if tricky because we must either have commutative
5015 operators or else A10 must not have side-effects. */
5017 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
5018 && operand_equal_p (a01, a11, 0))
5019 return fold (build (TREE_CODE (arg0), type,
5020 fold (build (code, type, a00, a10)),
5024 /* See if we can build a range comparison. */
5025 if (0 != (tem = fold_range_test (t)))
5028 /* Check for the possibility of merging component references. If our
5029 lhs is another similar operation, try to merge its rhs with our
5030 rhs. Then try to merge our lhs and rhs. */
5031 if (TREE_CODE (arg0) == code
5032 && 0 != (tem = fold_truthop (code, type,
5033 TREE_OPERAND (arg0, 1), arg1)))
5034 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
5036 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
5041 case TRUTH_ORIF_EXPR:
5042 /* Note that the operands of this must be ints
5043 and their values must be 0 or true.
5044 ("true" is a fixed value perhaps depending on the language.) */
5045 /* If first arg is constant true, return it. */
5046 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5049 /* If either arg is constant zero, drop it. */
5050 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
5051 return non_lvalue (arg1);
5052 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
5053 return non_lvalue (arg0);
5054 /* If second arg is constant true, result is true, but we must
5055 evaluate first arg. */
5056 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5057 return omit_one_operand (type, arg1, arg0);
5058 /* Likewise for first arg, but note this only occurs here for
5060 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5061 return omit_one_operand (type, arg0, arg1);
5064 case TRUTH_XOR_EXPR:
5065 /* If either arg is constant zero, drop it. */
5066 if (integer_zerop (arg0))
5067 return non_lvalue (arg1);
5068 if (integer_zerop (arg1))
5069 return non_lvalue (arg0);
5070 /* If either arg is constant true, this is a logical inversion. */
5071 if (integer_onep (arg0))
5072 return non_lvalue (invert_truthvalue (arg1));
5073 if (integer_onep (arg1))
5074 return non_lvalue (invert_truthvalue (arg0));
5083 /* If one arg is a constant integer, put it last. */
5084 if (TREE_CODE (arg0) == INTEGER_CST
5085 && TREE_CODE (arg1) != INTEGER_CST)
5087 TREE_OPERAND (t, 0) = arg1;
5088 TREE_OPERAND (t, 1) = arg0;
5089 arg0 = TREE_OPERAND (t, 0);
5090 arg1 = TREE_OPERAND (t, 1);
5091 code = swap_tree_comparison (code);
5092 TREE_SET_CODE (t, code);
5095 /* Convert foo++ == CONST into ++foo == CONST + INCR.
5096 First, see if one arg is constant; find the constant arg
5097 and the other one. */
5099 tree constop = 0, varop;
5100 int constopnum = -1;
5102 if (TREE_CONSTANT (arg1))
5103 constopnum = 1, constop = arg1, varop = arg0;
5104 if (TREE_CONSTANT (arg0))
5105 constopnum = 0, constop = arg0, varop = arg1;
5107 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
5109 /* This optimization is invalid for ordered comparisons
5110 if CONST+INCR overflows or if foo+incr might overflow.
5111 This optimization is invalid for floating point due to rounding.
5112 For pointer types we assume overflow doesn't happen. */
5113 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5114 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5115 && (code == EQ_EXPR || code == NE_EXPR)))
5118 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
5119 constop, TREE_OPERAND (varop, 1)));
5120 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
5122 /* If VAROP is a reference to a bitfield, we must mask
5123 the constant by the width of the field. */
5124 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5125 && DECL_BIT_FIELD(TREE_OPERAND
5126 (TREE_OPERAND (varop, 0), 1)))
5129 = TREE_INT_CST_LOW (DECL_SIZE
5131 (TREE_OPERAND (varop, 0), 1)));
5133 newconst = fold (build (BIT_AND_EXPR,
5134 TREE_TYPE (varop), newconst,
5135 convert (TREE_TYPE (varop),
5136 build_int_2 (size, 0))));
5140 t = build (code, type, TREE_OPERAND (t, 0),
5141 TREE_OPERAND (t, 1));
5142 TREE_OPERAND (t, constopnum) = newconst;
5146 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
5148 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5149 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5150 && (code == EQ_EXPR || code == NE_EXPR)))
5153 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
5154 constop, TREE_OPERAND (varop, 1)));
5155 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
5157 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5158 && DECL_BIT_FIELD(TREE_OPERAND
5159 (TREE_OPERAND (varop, 0), 1)))
5162 = TREE_INT_CST_LOW (DECL_SIZE
5164 (TREE_OPERAND (varop, 0), 1)));
5166 newconst = fold (build (BIT_AND_EXPR,
5167 TREE_TYPE (varop), newconst,
5168 convert (TREE_TYPE (varop),
5169 build_int_2 (size, 0))));
5173 t = build (code, type, TREE_OPERAND (t, 0),
5174 TREE_OPERAND (t, 1));
5175 TREE_OPERAND (t, constopnum) = newconst;
5181 /* Change X >= CST to X > (CST - 1) if CST is positive. */
5182 if (TREE_CODE (arg1) == INTEGER_CST
5183 && TREE_CODE (arg0) != INTEGER_CST
5184 && tree_int_cst_sgn (arg1) > 0)
5186 switch (TREE_CODE (t))
5190 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5191 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5196 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5197 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5205 /* If this is an EQ or NE comparison with zero and ARG0 is
5206 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5207 two operations, but the latter can be done in one less insn
5208 on machines that have only two-operand insns or on which a
5209 constant cannot be the first operand. */
5210 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5211 && TREE_CODE (arg0) == BIT_AND_EXPR)
5213 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5214 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5216 fold (build (code, type,
5217 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5219 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5220 TREE_OPERAND (arg0, 1),
5221 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5222 convert (TREE_TYPE (arg0),
5225 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5226 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5228 fold (build (code, type,
5229 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5231 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5232 TREE_OPERAND (arg0, 0),
5233 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5234 convert (TREE_TYPE (arg0),
5239 /* If this is an NE or EQ comparison of zero against the result of a
5240 signed MOD operation whose second operand is a power of 2, make
5241 the MOD operation unsigned since it is simpler and equivalent. */
5242 if ((code == NE_EXPR || code == EQ_EXPR)
5243 && integer_zerop (arg1)
5244 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5245 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5246 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5247 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5248 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5249 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5251 tree newtype = unsigned_type (TREE_TYPE (arg0));
5252 tree newmod = build (TREE_CODE (arg0), newtype,
5253 convert (newtype, TREE_OPERAND (arg0, 0)),
5254 convert (newtype, TREE_OPERAND (arg0, 1)));
5256 return build (code, type, newmod, convert (newtype, arg1));
5259 /* If this is an NE comparison of zero with an AND of one, remove the
5260 comparison since the AND will give the correct value. */
5261 if (code == NE_EXPR && integer_zerop (arg1)
5262 && TREE_CODE (arg0) == BIT_AND_EXPR
5263 && integer_onep (TREE_OPERAND (arg0, 1)))
5264 return convert (type, arg0);
5266 /* If we have (A & C) == C where C is a power of 2, convert this into
5267 (A & C) != 0. Similarly for NE_EXPR. */
5268 if ((code == EQ_EXPR || code == NE_EXPR)
5269 && TREE_CODE (arg0) == BIT_AND_EXPR
5270 && integer_pow2p (TREE_OPERAND (arg0, 1))
5271 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5272 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5273 arg0, integer_zero_node);
5275 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5276 and similarly for >= into !=. */
5277 if ((code == LT_EXPR || code == GE_EXPR)
5278 && TREE_UNSIGNED (TREE_TYPE (arg0))
5279 && TREE_CODE (arg1) == LSHIFT_EXPR
5280 && integer_onep (TREE_OPERAND (arg1, 0)))
5281 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5282 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5283 TREE_OPERAND (arg1, 1)),
5284 convert (TREE_TYPE (arg0), integer_zero_node));
5286 else if ((code == LT_EXPR || code == GE_EXPR)
5287 && TREE_UNSIGNED (TREE_TYPE (arg0))
5288 && (TREE_CODE (arg1) == NOP_EXPR
5289 || TREE_CODE (arg1) == CONVERT_EXPR)
5290 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5291 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5293 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5294 convert (TREE_TYPE (arg0),
5295 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5296 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5297 convert (TREE_TYPE (arg0), integer_zero_node));
5299 /* Simplify comparison of something with itself. (For IEEE
5300 floating-point, we can only do some of these simplifications.) */
5301 if (operand_equal_p (arg0, arg1, 0))
5308 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5310 if (type == integer_type_node)
5311 return integer_one_node;
5313 t = build_int_2 (1, 0);
5314 TREE_TYPE (t) = type;
5318 TREE_SET_CODE (t, code);
5322 /* For NE, we can only do this simplification if integer. */
5323 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5325 /* ... fall through ... */
5328 if (type == integer_type_node)
5329 return integer_zero_node;
5331 t = build_int_2 (0, 0);
5332 TREE_TYPE (t) = type;
5339 /* An unsigned comparison against 0 can be simplified. */
5340 if (integer_zerop (arg1)
5341 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5342 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5343 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5345 switch (TREE_CODE (t))
5349 TREE_SET_CODE (t, NE_EXPR);
5353 TREE_SET_CODE (t, EQ_EXPR);
5356 return omit_one_operand (type,
5357 convert (type, integer_one_node),
5360 return omit_one_operand (type,
5361 convert (type, integer_zero_node),
5368 /* An unsigned <= 0x7fffffff can be simplified. */
5370 int width = TYPE_PRECISION (TREE_TYPE (arg1));
5371 if (TREE_CODE (arg1) == INTEGER_CST
5372 && ! TREE_CONSTANT_OVERFLOW (arg1)
5373 && width <= HOST_BITS_PER_WIDE_INT
5374 && TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
5375 && TREE_INT_CST_HIGH (arg1) == 0
5376 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5377 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5378 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5380 switch (TREE_CODE (t))
5383 return fold (build (GE_EXPR, type,
5384 convert (signed_type (TREE_TYPE (arg0)),
5386 convert (signed_type (TREE_TYPE (arg1)),
5387 integer_zero_node)));
5389 return fold (build (LT_EXPR, type,
5390 convert (signed_type (TREE_TYPE (arg0)),
5392 convert (signed_type (TREE_TYPE (arg1)),
5393 integer_zero_node)));
5398 /* If we are comparing an expression that just has comparisons
5399 of two integer values, arithmetic expressions of those comparisons,
5400 and constants, we can simplify it. There are only three cases
5401 to check: the two values can either be equal, the first can be
5402 greater, or the second can be greater. Fold the expression for
5403 those three values. Since each value must be 0 or 1, we have
5404 eight possibilities, each of which corresponds to the constant 0
5405 or 1 or one of the six possible comparisons.
5407 This handles common cases like (a > b) == 0 but also handles
5408 expressions like ((x > y) - (y > x)) > 0, which supposedly
5409 occur in macroized code. */
5411 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5413 tree cval1 = 0, cval2 = 0;
5416 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5417 /* Don't handle degenerate cases here; they should already
5418 have been handled anyway. */
5419 && cval1 != 0 && cval2 != 0
5420 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5421 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5422 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5423 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
5424 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
5425 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5426 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5428 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5429 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5431 /* We can't just pass T to eval_subst in case cval1 or cval2
5432 was the same as ARG1. */
5435 = fold (build (code, type,
5436 eval_subst (arg0, cval1, maxval, cval2, minval),
5439 = fold (build (code, type,
5440 eval_subst (arg0, cval1, maxval, cval2, maxval),
5443 = fold (build (code, type,
5444 eval_subst (arg0, cval1, minval, cval2, maxval),
5447 /* All three of these results should be 0 or 1. Confirm they
5448 are. Then use those values to select the proper code
5451 if ((integer_zerop (high_result)
5452 || integer_onep (high_result))
5453 && (integer_zerop (equal_result)
5454 || integer_onep (equal_result))
5455 && (integer_zerop (low_result)
5456 || integer_onep (low_result)))
5458 /* Make a 3-bit mask with the high-order bit being the
5459 value for `>', the next for '=', and the low for '<'. */
5460 switch ((integer_onep (high_result) * 4)
5461 + (integer_onep (equal_result) * 2)
5462 + integer_onep (low_result))
5466 return omit_one_operand (type, integer_zero_node, arg0);
5487 return omit_one_operand (type, integer_one_node, arg0);
5490 t = build (code, type, cval1, cval2);
5492 return save_expr (t);
5499 /* If this is a comparison of a field, we may be able to simplify it. */
5500 if ((TREE_CODE (arg0) == COMPONENT_REF
5501 || TREE_CODE (arg0) == BIT_FIELD_REF)
5502 && (code == EQ_EXPR || code == NE_EXPR)
5503 /* Handle the constant case even without -O
5504 to make sure the warnings are given. */
5505 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5507 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5511 /* If this is a comparison of complex values and either or both
5512 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5513 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5514 may prevent needless evaluations. */
5515 if ((code == EQ_EXPR || code == NE_EXPR)
5516 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5517 && (TREE_CODE (arg0) == COMPLEX_EXPR
5518 || TREE_CODE (arg1) == COMPLEX_EXPR))
5520 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5521 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5522 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5523 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5524 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5526 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5529 fold (build (code, type, real0, real1)),
5530 fold (build (code, type, imag0, imag1))));
5533 /* From here on, the only cases we handle are when the result is
5534 known to be a constant.
5536 To compute GT, swap the arguments and do LT.
5537 To compute GE, do LT and invert the result.
5538 To compute LE, swap the arguments, do LT and invert the result.
5539 To compute NE, do EQ and invert the result.
5541 Therefore, the code below must handle only EQ and LT. */
5543 if (code == LE_EXPR || code == GT_EXPR)
5545 tem = arg0, arg0 = arg1, arg1 = tem;
5546 code = swap_tree_comparison (code);
5549 /* Note that it is safe to invert for real values here because we
5550 will check below in the one case that it matters. */
5553 if (code == NE_EXPR || code == GE_EXPR)
5556 code = invert_tree_comparison (code);
5559 /* Compute a result for LT or EQ if args permit;
5560 otherwise return T. */
5561 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5563 if (code == EQ_EXPR)
5564 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5565 == TREE_INT_CST_LOW (arg1))
5566 && (TREE_INT_CST_HIGH (arg0)
5567 == TREE_INT_CST_HIGH (arg1)),
5570 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5571 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5572 : INT_CST_LT (arg0, arg1)),
5576 #if 0 /* This is no longer useful, but breaks some real code. */
5577 /* Assume a nonexplicit constant cannot equal an explicit one,
5578 since such code would be undefined anyway.
5579 Exception: on sysvr4, using #pragma weak,
5580 a label can come out as 0. */
5581 else if (TREE_CODE (arg1) == INTEGER_CST
5582 && !integer_zerop (arg1)
5583 && TREE_CONSTANT (arg0)
5584 && TREE_CODE (arg0) == ADDR_EXPR
5586 t1 = build_int_2 (0, 0);
5588 /* Two real constants can be compared explicitly. */
5589 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5591 /* If either operand is a NaN, the result is false with two
5592 exceptions: First, an NE_EXPR is true on NaNs, but that case
5593 is already handled correctly since we will be inverting the
5594 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5595 or a GE_EXPR into a LT_EXPR, we must return true so that it
5596 will be inverted into false. */
5598 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5599 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5600 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5602 else if (code == EQ_EXPR)
5603 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5604 TREE_REAL_CST (arg1)),
5607 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5608 TREE_REAL_CST (arg1)),
5612 if (t1 == NULL_TREE)
5616 TREE_INT_CST_LOW (t1) ^= 1;
5618 TREE_TYPE (t1) = type;
5622 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5623 so all simple results must be passed through pedantic_non_lvalue. */
5624 if (TREE_CODE (arg0) == INTEGER_CST)
5625 return pedantic_non_lvalue
5626 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5627 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5628 return pedantic_omit_one_operand (type, arg1, arg0);
5630 /* If the second operand is zero, invert the comparison and swap
5631 the second and third operands. Likewise if the second operand
5632 is constant and the third is not or if the third operand is
5633 equivalent to the first operand of the comparison. */
5635 if (integer_zerop (arg1)
5636 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5637 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5638 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5639 TREE_OPERAND (t, 2),
5640 TREE_OPERAND (arg0, 1))))
5642 /* See if this can be inverted. If it can't, possibly because
5643 it was a floating-point inequality comparison, don't do
5645 tem = invert_truthvalue (arg0);
5647 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5649 t = build (code, type, tem,
5650 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5652 arg1 = TREE_OPERAND (t, 2);
5657 /* If we have A op B ? A : C, we may be able to convert this to a
5658 simpler expression, depending on the operation and the values
5659 of B and C. IEEE floating point prevents this though,
5660 because A or B might be -0.0 or a NaN. */
5662 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5663 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5664 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5666 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5667 arg1, TREE_OPERAND (arg0, 1)))
5669 tree arg2 = TREE_OPERAND (t, 2);
5670 enum tree_code comp_code = TREE_CODE (arg0);
5674 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5675 depending on the comparison operation. */
5676 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5677 ? real_zerop (TREE_OPERAND (arg0, 1))
5678 : integer_zerop (TREE_OPERAND (arg0, 1)))
5679 && TREE_CODE (arg2) == NEGATE_EXPR
5680 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5684 return pedantic_non_lvalue
5685 (fold (build1 (NEGATE_EXPR, type, arg1)));
5687 return pedantic_non_lvalue (convert (type, arg1));
5690 return pedantic_non_lvalue
5691 (convert (type, fold (build1 (ABS_EXPR,
5692 TREE_TYPE (arg1), arg1))));
5695 return pedantic_non_lvalue
5696 (fold (build1 (NEGATE_EXPR, type,
5698 fold (build1 (ABS_EXPR,
5705 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5708 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5710 if (comp_code == NE_EXPR)
5711 return pedantic_non_lvalue (convert (type, arg1));
5712 else if (comp_code == EQ_EXPR)
5713 return pedantic_non_lvalue (convert (type, integer_zero_node));
5716 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5717 or max (A, B), depending on the operation. */
5719 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5720 arg2, TREE_OPERAND (arg0, 0)))
5722 tree comp_op0 = TREE_OPERAND (arg0, 0);
5723 tree comp_op1 = TREE_OPERAND (arg0, 1);
5724 tree comp_type = TREE_TYPE (comp_op0);
5729 return pedantic_non_lvalue (convert (type, arg2));
5731 return pedantic_non_lvalue (convert (type, arg1));
5734 /* In C++ a ?: expression can be an lvalue, so put the
5735 operand which will be used if they are equal first
5736 so that we can convert this back to the
5737 corresponding COND_EXPR. */
5738 return pedantic_non_lvalue
5739 (convert (type, (fold (build (MIN_EXPR, comp_type,
5740 (comp_code == LE_EXPR
5741 ? comp_op0 : comp_op1),
5742 (comp_code == LE_EXPR
5743 ? comp_op1 : comp_op0))))));
5747 return pedantic_non_lvalue
5748 (convert (type, fold (build (MAX_EXPR, comp_type,
5749 (comp_code == GE_EXPR
5750 ? comp_op0 : comp_op1),
5751 (comp_code == GE_EXPR
5752 ? comp_op1 : comp_op0)))));
5759 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5760 we might still be able to simplify this. For example,
5761 if C1 is one less or one more than C2, this might have started
5762 out as a MIN or MAX and been transformed by this function.
5763 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5765 if (INTEGRAL_TYPE_P (type)
5766 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5767 && TREE_CODE (arg2) == INTEGER_CST)
5771 /* We can replace A with C1 in this case. */
5772 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5773 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5774 TREE_OPERAND (t, 2));
5778 /* If C1 is C2 + 1, this is min(A, C2). */
5779 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5780 && operand_equal_p (TREE_OPERAND (arg0, 1),
5781 const_binop (PLUS_EXPR, arg2,
5782 integer_one_node, 0), 1))
5783 return pedantic_non_lvalue
5784 (fold (build (MIN_EXPR, type, arg1, arg2)));
5788 /* If C1 is C2 - 1, this is min(A, C2). */
5789 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5790 && operand_equal_p (TREE_OPERAND (arg0, 1),
5791 const_binop (MINUS_EXPR, arg2,
5792 integer_one_node, 0), 1))
5793 return pedantic_non_lvalue
5794 (fold (build (MIN_EXPR, type, arg1, arg2)));
5798 /* If C1 is C2 - 1, this is max(A, C2). */
5799 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5800 && operand_equal_p (TREE_OPERAND (arg0, 1),
5801 const_binop (MINUS_EXPR, arg2,
5802 integer_one_node, 0), 1))
5803 return pedantic_non_lvalue
5804 (fold (build (MAX_EXPR, type, arg1, arg2)));
5808 /* If C1 is C2 + 1, this is max(A, C2). */
5809 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5810 && operand_equal_p (TREE_OPERAND (arg0, 1),
5811 const_binop (PLUS_EXPR, arg2,
5812 integer_one_node, 0), 1))
5813 return pedantic_non_lvalue
5814 (fold (build (MAX_EXPR, type, arg1, arg2)));
5823 /* If the second operand is simpler than the third, swap them
5824 since that produces better jump optimization results. */
5825 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5826 || TREE_CODE (arg1) == SAVE_EXPR)
5827 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5828 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5829 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5831 /* See if this can be inverted. If it can't, possibly because
5832 it was a floating-point inequality comparison, don't do
5834 tem = invert_truthvalue (arg0);
5836 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5838 t = build (code, type, tem,
5839 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5841 arg1 = TREE_OPERAND (t, 2);
5846 /* Convert A ? 1 : 0 to simply A. */
5847 if (integer_onep (TREE_OPERAND (t, 1))
5848 && integer_zerop (TREE_OPERAND (t, 2))
5849 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5850 call to fold will try to move the conversion inside
5851 a COND, which will recurse. In that case, the COND_EXPR
5852 is probably the best choice, so leave it alone. */
5853 && type == TREE_TYPE (arg0))
5854 return pedantic_non_lvalue (arg0);
5856 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5857 operation is simply A & 2. */
5859 if (integer_zerop (TREE_OPERAND (t, 2))
5860 && TREE_CODE (arg0) == NE_EXPR
5861 && integer_zerop (TREE_OPERAND (arg0, 1))
5862 && integer_pow2p (arg1)
5863 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5864 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5866 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5871 /* When pedantic, a compound expression can be neither an lvalue
5872 nor an integer constant expression. */
5873 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5875 /* Don't let (0, 0) be null pointer constant. */
5876 if (integer_zerop (arg1))
5877 return non_lvalue (arg1);
5882 return build_complex (type, arg0, arg1);
5886 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5888 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5889 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5890 TREE_OPERAND (arg0, 1));
5891 else if (TREE_CODE (arg0) == COMPLEX_CST)
5892 return TREE_REALPART (arg0);
5893 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5894 return fold (build (TREE_CODE (arg0), type,
5895 fold (build1 (REALPART_EXPR, type,
5896 TREE_OPERAND (arg0, 0))),
5897 fold (build1 (REALPART_EXPR,
5898 type, TREE_OPERAND (arg0, 1)))));
5902 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5903 return convert (type, integer_zero_node);
5904 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5905 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5906 TREE_OPERAND (arg0, 0));
5907 else if (TREE_CODE (arg0) == COMPLEX_CST)
5908 return TREE_IMAGPART (arg0);
5909 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5910 return fold (build (TREE_CODE (arg0), type,
5911 fold (build1 (IMAGPART_EXPR, type,
5912 TREE_OPERAND (arg0, 0))),
5913 fold (build1 (IMAGPART_EXPR, type,
5914 TREE_OPERAND (arg0, 1)))));
5917 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5919 case CLEANUP_POINT_EXPR:
5920 if (! TREE_SIDE_EFFECTS (arg0))
5921 return TREE_OPERAND (t, 0);
5924 enum tree_code code0 = TREE_CODE (arg0);
5925 int kind0 = TREE_CODE_CLASS (code0);
5926 tree arg00 = TREE_OPERAND (arg0, 0);
5929 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5930 return fold (build1 (code0, type,
5931 fold (build1 (CLEANUP_POINT_EXPR,
5932 TREE_TYPE (arg00), arg00))));
5934 if (kind0 == '<' || kind0 == '2'
5935 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5936 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5937 || code0 == TRUTH_XOR_EXPR)
5939 arg01 = TREE_OPERAND (arg0, 1);
5941 if (! TREE_SIDE_EFFECTS (arg00))
5942 return fold (build (code0, type, arg00,
5943 fold (build1 (CLEANUP_POINT_EXPR,
5944 TREE_TYPE (arg01), arg01))));
5946 if (! TREE_SIDE_EFFECTS (arg01))
5947 return fold (build (code0, type,
5948 fold (build1 (CLEANUP_POINT_EXPR,
5949 TREE_TYPE (arg00), arg00)),
5958 } /* switch (code) */
5961 /* Determine if first argument is a multiple of second argument.
5962 Return 0 if it is not, or is not easily determined to so be.
5964 An example of the sort of thing we care about (at this point --
5965 this routine could surely be made more general, and expanded
5966 to do what the *_DIV_EXPR's fold() cases do now) is discovering
5969 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5975 when we know that the two `SAVE_EXPR (J * 8)' nodes are the
5976 same node (which means they will have the same value at run
5977 time, even though we don't know when they'll be assigned).
5979 This code also handles discovering that
5981 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5987 (of course) so we don't have to worry about dealing with a
5990 Note that we _look_ inside a SAVE_EXPR only to determine
5991 how it was calculated; it is not safe for fold() to do much
5992 of anything else with the internals of a SAVE_EXPR, since
5993 fold() cannot know when it will be evaluated at run time.
5994 For example, the latter example above _cannot_ be implemented
5999 or any variant thereof, since the value of J at evaluation time
6000 of the original SAVE_EXPR is not necessarily the same at the time
6001 the new expression is evaluated. The only optimization of this
6002 sort that would be valid is changing
6004 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
6010 SAVE_EXPR (I) * SAVE_EXPR (J)
6012 (where the same SAVE_EXPR (J) is used in the original and the
6013 transformed version). */
6016 multiple_of_p (type, top, bottom)
6021 if (operand_equal_p (top, bottom, 0))
6024 if (TREE_CODE (type) != INTEGER_TYPE)
6027 switch (TREE_CODE (top))
6030 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6031 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6035 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6036 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6039 /* Punt if conversion from non-integral or wider integral type. */
6040 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
6041 || (TYPE_PRECISION (type)
6042 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
6046 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
6049 if ((TREE_CODE (bottom) != INTEGER_CST)
6050 || (tree_int_cst_sgn (top) < 0)
6051 || (tree_int_cst_sgn (bottom) < 0))
6053 return integer_zerop (const_binop (TRUNC_MOD_EXPR,