1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /*@@ This file should be rewritten to use an arbitrary precision
22 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
23 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
24 @@ The routines that translate from the ap rep should
25 @@ warn if precision et. al. is lost.
26 @@ This would also make life easier when this technology is used
27 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type takes a constant and prior overflow indicator, and
43 forces the value to fit the type. It returns an overflow indicator. */
51 /* Handle floating overflow for `const_binop'. */
52 static jmp_buf float_error;
54 static void encode PROTO((HOST_WIDE_INT *,
55 HOST_WIDE_INT, HOST_WIDE_INT));
56 static void decode PROTO((HOST_WIDE_INT *,
57 HOST_WIDE_INT *, HOST_WIDE_INT *));
58 int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
59 HOST_WIDE_INT, HOST_WIDE_INT,
60 HOST_WIDE_INT, HOST_WIDE_INT *,
61 HOST_WIDE_INT *, HOST_WIDE_INT *,
63 static int split_tree PROTO((tree, enum tree_code, tree *,
65 static tree int_const_binop PROTO((enum tree_code, tree, tree, int, int));
66 static tree const_binop PROTO((enum tree_code, tree, tree, int));
67 static tree fold_convert PROTO((tree, tree));
68 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
69 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
70 static int truth_value_p PROTO((enum tree_code));
71 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
72 static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
73 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
74 static tree omit_one_operand PROTO((tree, tree, tree));
75 static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
76 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
77 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
78 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
80 static tree decode_field_reference PROTO((tree, int *, int *,
81 enum machine_mode *, int *,
82 int *, tree *, tree *));
83 static int all_ones_mask_p PROTO((tree, int));
84 static int simple_operand_p PROTO((tree));
85 static tree range_binop PROTO((enum tree_code, tree, tree, int,
87 static tree make_range PROTO((tree, int *, tree *, tree *));
88 static tree build_range_check PROTO((tree, tree, int, tree, tree));
89 static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
91 static tree fold_range_test PROTO((tree));
92 static tree unextend PROTO((tree, int, int, tree));
93 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
94 static tree strip_compound_expr PROTO((tree, tree));
95 static int multiple_of_p PROTO((tree, tree, tree));
101 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
102 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
103 Then this yields nonzero if overflow occurred during the addition.
104 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
105 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
106 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
108 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
109 We do that by representing the two-word integer in 4 words, with only
110 HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
113 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
114 #define HIGHPART(x) \
115 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
116 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
118 /* Unpack a two-word integer into 4 words.
119 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
120 WORDS points to the array of HOST_WIDE_INTs. */
123 encode (words, low, hi)
124 HOST_WIDE_INT *words;
125 HOST_WIDE_INT low, hi;
127 words[0] = LOWPART (low);
128 words[1] = HIGHPART (low);
129 words[2] = LOWPART (hi);
130 words[3] = HIGHPART (hi);
133 /* Pack an array of 4 words into a two-word integer.
134 WORDS points to the array of words.
135 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
138 decode (words, low, hi)
139 HOST_WIDE_INT *words;
140 HOST_WIDE_INT *low, *hi;
142 *low = words[0] | words[1] * BASE;
143 *hi = words[2] | words[3] * BASE;
146 /* Make the integer constant T valid for its type
147 by setting to 0 or 1 all the bits in the constant
148 that don't belong in the type.
149 Yield 1 if a signed overflow occurs, 0 otherwise.
150 If OVERFLOW is nonzero, a signed overflow has already occurred
151 in calculating T, so propagate it.
153 Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
157 force_fit_type (t, overflow)
161 HOST_WIDE_INT low, high;
164 if (TREE_CODE (t) == REAL_CST)
166 #ifdef CHECK_FLOAT_VALUE
167 CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
173 else if (TREE_CODE (t) != INTEGER_CST)
176 low = TREE_INT_CST_LOW (t);
177 high = TREE_INT_CST_HIGH (t);
179 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
182 prec = TYPE_PRECISION (TREE_TYPE (t));
184 /* First clear all bits that are beyond the type's precision. */
186 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
188 else if (prec > HOST_BITS_PER_WIDE_INT)
190 TREE_INT_CST_HIGH (t)
191 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
195 TREE_INT_CST_HIGH (t) = 0;
196 if (prec < HOST_BITS_PER_WIDE_INT)
197 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
200 /* Unsigned types do not suffer sign extension or overflow. */
201 if (TREE_UNSIGNED (TREE_TYPE (t)))
204 /* If the value's sign bit is set, extend the sign. */
205 if (prec != 2 * HOST_BITS_PER_WIDE_INT
206 && (prec > HOST_BITS_PER_WIDE_INT
207 ? (TREE_INT_CST_HIGH (t)
208 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
209 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
211 /* Value is negative:
212 set to 1 all the bits that are outside this type's precision. */
213 if (prec > HOST_BITS_PER_WIDE_INT)
215 TREE_INT_CST_HIGH (t)
216 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
220 TREE_INT_CST_HIGH (t) = -1;
221 if (prec < HOST_BITS_PER_WIDE_INT)
222 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
226 /* Yield nonzero if signed overflow occurred. */
228 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
232 /* Add two doubleword integers with doubleword result.
233 Each argument is given as two `HOST_WIDE_INT' pieces.
234 One argument is L1 and H1; the other, L2 and H2.
235 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
238 add_double (l1, h1, l2, h2, lv, hv)
239 HOST_WIDE_INT l1, h1, l2, h2;
240 HOST_WIDE_INT *lv, *hv;
245 h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
249 return overflow_sum_sign (h1, h2, h);
252 /* Negate a doubleword integer with doubleword result.
253 Return nonzero if the operation overflows, assuming it's signed.
254 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
255 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
258 neg_double (l1, h1, lv, hv)
259 HOST_WIDE_INT l1, h1;
260 HOST_WIDE_INT *lv, *hv;
266 return (*hv & h1) < 0;
276 /* Multiply two doubleword integers with doubleword result.
277 Return nonzero if the operation overflows, assuming it's signed.
278 Each argument is given as two `HOST_WIDE_INT' pieces.
279 One argument is L1 and H1; the other, L2 and H2.
280 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
283 mul_double (l1, h1, l2, h2, lv, hv)
284 HOST_WIDE_INT l1, h1, l2, h2;
285 HOST_WIDE_INT *lv, *hv;
287 HOST_WIDE_INT arg1[4];
288 HOST_WIDE_INT arg2[4];
289 HOST_WIDE_INT prod[4 * 2];
290 register unsigned HOST_WIDE_INT carry;
291 register int i, j, k;
292 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
294 encode (arg1, l1, h1);
295 encode (arg2, l2, h2);
297 bzero ((char *) prod, sizeof prod);
299 for (i = 0; i < 4; i++)
302 for (j = 0; j < 4; j++)
305 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
306 carry += arg1[i] * arg2[j];
307 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
309 prod[k] = LOWPART (carry);
310 carry = HIGHPART (carry);
315 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
317 /* Check for overflow by calculating the top half of the answer in full;
318 it should agree with the low half's sign bit. */
319 decode (prod+4, &toplow, &tophigh);
322 neg_double (l2, h2, &neglow, &neghigh);
323 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
327 neg_double (l1, h1, &neglow, &neghigh);
328 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
330 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
333 /* Shift the doubleword integer in L1, H1 left by COUNT places
334 keeping only PREC bits of result.
335 Shift right if COUNT is negative.
336 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
337 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
340 lshift_double (l1, h1, count, prec, lv, hv, arith)
341 HOST_WIDE_INT l1, h1, count;
343 HOST_WIDE_INT *lv, *hv;
348 rshift_double (l1, h1, - count, prec, lv, hv, arith);
352 #ifdef SHIFT_COUNT_TRUNCATED
353 if (SHIFT_COUNT_TRUNCATED)
357 if (count >= HOST_BITS_PER_WIDE_INT)
359 *hv = (unsigned HOST_WIDE_INT) l1 << count - HOST_BITS_PER_WIDE_INT;
364 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
365 | ((unsigned HOST_WIDE_INT) l1 >> HOST_BITS_PER_WIDE_INT - count - 1 >> 1));
366 *lv = (unsigned HOST_WIDE_INT) l1 << count;
370 /* Shift the doubleword integer in L1, H1 right by COUNT places
371 keeping only PREC bits of result. COUNT must be positive.
372 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
373 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
376 rshift_double (l1, h1, count, prec, lv, hv, arith)
377 HOST_WIDE_INT l1, h1, count;
379 HOST_WIDE_INT *lv, *hv;
382 unsigned HOST_WIDE_INT signmask;
384 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
387 #ifdef SHIFT_COUNT_TRUNCATED
388 if (SHIFT_COUNT_TRUNCATED)
392 if (count >= HOST_BITS_PER_WIDE_INT)
395 *lv = ((signmask << 2 * HOST_BITS_PER_WIDE_INT - count - 1 << 1)
396 | ((unsigned HOST_WIDE_INT) h1 >> count - HOST_BITS_PER_WIDE_INT));
400 *lv = (((unsigned HOST_WIDE_INT) l1 >> count)
401 | ((unsigned HOST_WIDE_INT) h1 << HOST_BITS_PER_WIDE_INT - count - 1 << 1));
402 *hv = ((signmask << HOST_BITS_PER_WIDE_INT - count)
403 | ((unsigned HOST_WIDE_INT) h1 >> count));
407 /* Rotate the doubleword integer in L1, H1 left by COUNT places
408 keeping only PREC bits of result.
409 Rotate right if COUNT is negative.
410 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
413 lrotate_double (l1, h1, count, prec, lv, hv)
414 HOST_WIDE_INT l1, h1, count;
416 HOST_WIDE_INT *lv, *hv;
418 HOST_WIDE_INT s1l, s1h, s2l, s2h;
424 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
425 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
430 /* Rotate the doubleword integer in L1, H1 left by COUNT places
431 keeping only PREC bits of result. COUNT must be positive.
432 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
435 rrotate_double (l1, h1, count, prec, lv, hv)
436 HOST_WIDE_INT l1, h1, count;
438 HOST_WIDE_INT *lv, *hv;
440 HOST_WIDE_INT s1l, s1h, s2l, s2h;
446 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
447 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
452 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
453 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
454 CODE is a tree code for a kind of division, one of
455 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
457 It controls how the quotient is rounded to a integer.
458 Return nonzero if the operation overflows.
459 UNS nonzero says do unsigned division. */
462 div_and_round_double (code, uns,
463 lnum_orig, hnum_orig, lden_orig, hden_orig,
464 lquo, hquo, lrem, hrem)
467 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
468 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
469 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
472 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
473 HOST_WIDE_INT den[4], quo[4];
475 unsigned HOST_WIDE_INT work;
476 register unsigned HOST_WIDE_INT carry = 0;
477 HOST_WIDE_INT lnum = lnum_orig;
478 HOST_WIDE_INT hnum = hnum_orig;
479 HOST_WIDE_INT lden = lden_orig;
480 HOST_WIDE_INT hden = hden_orig;
483 if ((hden == 0) && (lden == 0))
484 overflow = 1, lden = 1;
486 /* calculate quotient sign and convert operands to unsigned. */
492 /* (minimum integer) / (-1) is the only overflow case. */
493 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
499 neg_double (lden, hden, &lden, &hden);
503 if (hnum == 0 && hden == 0)
504 { /* single precision */
506 /* This unsigned division rounds toward zero. */
507 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
512 { /* trivial case: dividend < divisor */
513 /* hden != 0 already checked. */
520 bzero ((char *) quo, sizeof quo);
522 bzero ((char *) num, sizeof num); /* to zero 9th element */
523 bzero ((char *) den, sizeof den);
525 encode (num, lnum, hnum);
526 encode (den, lden, hden);
528 /* Special code for when the divisor < BASE. */
529 if (hden == 0 && lden < BASE)
531 /* hnum != 0 already checked. */
532 for (i = 4 - 1; i >= 0; i--)
534 work = num[i] + carry * BASE;
535 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
536 carry = work % (unsigned HOST_WIDE_INT) lden;
541 /* Full double precision division,
542 with thanks to Don Knuth's "Seminumerical Algorithms". */
543 int num_hi_sig, den_hi_sig;
544 unsigned HOST_WIDE_INT quo_est, scale;
546 /* Find the highest non-zero divisor digit. */
547 for (i = 4 - 1; ; i--)
553 /* Insure that the first digit of the divisor is at least BASE/2.
554 This is required by the quotient digit estimation algorithm. */
556 scale = BASE / (den[den_hi_sig] + 1);
557 if (scale > 1) { /* scale divisor and dividend */
559 for (i = 0; i <= 4 - 1; i++) {
560 work = (num[i] * scale) + carry;
561 num[i] = LOWPART (work);
562 carry = HIGHPART (work);
565 for (i = 0; i <= 4 - 1; i++) {
566 work = (den[i] * scale) + carry;
567 den[i] = LOWPART (work);
568 carry = HIGHPART (work);
569 if (den[i] != 0) den_hi_sig = i;
576 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
577 /* guess the next quotient digit, quo_est, by dividing the first
578 two remaining dividend digits by the high order quotient digit.
579 quo_est is never low and is at most 2 high. */
580 unsigned HOST_WIDE_INT tmp;
582 num_hi_sig = i + den_hi_sig + 1;
583 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
584 if (num[num_hi_sig] != den[den_hi_sig])
585 quo_est = work / den[den_hi_sig];
589 /* refine quo_est so it's usually correct, and at most one high. */
590 tmp = work - quo_est * den[den_hi_sig];
592 && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
595 /* Try QUO_EST as the quotient digit, by multiplying the
596 divisor by QUO_EST and subtracting from the remaining dividend.
597 Keep in mind that QUO_EST is the I - 1st digit. */
600 for (j = 0; j <= den_hi_sig; j++)
602 work = quo_est * den[j] + carry;
603 carry = HIGHPART (work);
604 work = num[i + j] - LOWPART (work);
605 num[i + j] = LOWPART (work);
606 carry += HIGHPART (work) != 0;
609 /* if quo_est was high by one, then num[i] went negative and
610 we need to correct things. */
612 if (num[num_hi_sig] < carry)
615 carry = 0; /* add divisor back in */
616 for (j = 0; j <= den_hi_sig; j++)
618 work = num[i + j] + den[j] + carry;
619 carry = HIGHPART (work);
620 num[i + j] = LOWPART (work);
622 num [num_hi_sig] += carry;
625 /* store the quotient digit. */
630 decode (quo, lquo, hquo);
633 /* if result is negative, make it so. */
635 neg_double (*lquo, *hquo, lquo, hquo);
637 /* compute trial remainder: rem = num - (quo * den) */
638 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
639 neg_double (*lrem, *hrem, lrem, hrem);
640 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
645 case TRUNC_MOD_EXPR: /* round toward zero */
646 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
650 case FLOOR_MOD_EXPR: /* round toward negative infinity */
651 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
654 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
657 else return overflow;
661 case CEIL_MOD_EXPR: /* round toward positive infinity */
662 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
664 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
667 else return overflow;
671 case ROUND_MOD_EXPR: /* round to closest integer */
673 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
674 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
676 /* get absolute values */
677 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
678 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
680 /* if (2 * abs (lrem) >= abs (lden)) */
681 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
682 labs_rem, habs_rem, <wice, &htwice);
683 if (((unsigned HOST_WIDE_INT) habs_den
684 < (unsigned HOST_WIDE_INT) htwice)
685 || (((unsigned HOST_WIDE_INT) habs_den
686 == (unsigned HOST_WIDE_INT) htwice)
687 && ((HOST_WIDE_INT unsigned) labs_den
688 < (unsigned HOST_WIDE_INT) ltwice)))
692 add_double (*lquo, *hquo,
693 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
696 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
699 else return overflow;
707 /* compute true remainder: rem = num - (quo * den) */
708 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
709 neg_double (*lrem, *hrem, lrem, hrem);
710 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
714 #ifndef REAL_ARITHMETIC
715 /* Effectively truncate a real value to represent the nearest possible value
716 in a narrower mode. The result is actually represented in the same data
717 type as the argument, but its value is usually different.
719 A trap may occur during the FP operations and it is the responsibility
720 of the calling function to have a handler established. */
723 real_value_truncate (mode, arg)
724 enum machine_mode mode;
727 return REAL_VALUE_TRUNCATE (mode, arg);
730 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
732 /* Check for infinity in an IEEE double precision number. */
738 /* The IEEE 64-bit double format. */
743 unsigned exponent : 11;
744 unsigned mantissa1 : 20;
749 unsigned mantissa1 : 20;
750 unsigned exponent : 11;
756 if (u.big_endian.sign == 1)
759 return (u.big_endian.exponent == 2047
760 && u.big_endian.mantissa1 == 0
761 && u.big_endian.mantissa2 == 0);
766 return (u.little_endian.exponent == 2047
767 && u.little_endian.mantissa1 == 0
768 && u.little_endian.mantissa2 == 0);
772 /* Check whether an IEEE double precision number is a NaN. */
778 /* The IEEE 64-bit double format. */
783 unsigned exponent : 11;
784 unsigned mantissa1 : 20;
789 unsigned mantissa1 : 20;
790 unsigned exponent : 11;
796 if (u.big_endian.sign == 1)
799 return (u.big_endian.exponent == 2047
800 && (u.big_endian.mantissa1 != 0
801 || u.big_endian.mantissa2 != 0));
806 return (u.little_endian.exponent == 2047
807 && (u.little_endian.mantissa1 != 0
808 || u.little_endian.mantissa2 != 0));
812 /* Check for a negative IEEE double precision number. */
818 /* The IEEE 64-bit double format. */
823 unsigned exponent : 11;
824 unsigned mantissa1 : 20;
829 unsigned mantissa1 : 20;
830 unsigned exponent : 11;
836 if (u.big_endian.sign == 1)
839 return u.big_endian.sign;
844 return u.little_endian.sign;
847 #else /* Target not IEEE */
849 /* Let's assume other float formats don't have infinity.
850 (This can be overridden by redefining REAL_VALUE_ISINF.) */
858 /* Let's assume other float formats don't have NaNs.
859 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
867 /* Let's assume other float formats don't have minus zero.
868 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
875 #endif /* Target not IEEE */
877 /* Try to change R into its exact multiplicative inverse in machine mode
878 MODE. Return nonzero function value if successful. */
881 exact_real_inverse (mode, r)
882 enum machine_mode mode;
892 /* Usually disable if bounds checks are not reliable. */
893 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
896 /* Set array index to the less significant bits in the unions, depending
897 on the endian-ness of the host doubles.
898 Disable if insufficient information on the data structure. */
899 #if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
902 #if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
905 #if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
908 #define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
913 if (setjmp (float_error))
915 /* Don't do the optimization if there was an arithmetic error. */
917 set_float_handler (NULL_PTR);
920 set_float_handler (float_error);
922 /* Domain check the argument. */
928 if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
932 /* Compute the reciprocal and check for numerical exactness.
933 It is unnecessary to check all the significand bits to determine
934 whether X is a power of 2. If X is not, then it is impossible for
935 the bottom half significand of both X and 1/X to be all zero bits.
936 Hence we ignore the data structure of the top half and examine only
937 the low order bits of the two significands. */
939 if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
942 /* Truncate to the required mode and range-check the result. */
943 y.d = REAL_VALUE_TRUNCATE (mode, t.d);
944 #ifdef CHECK_FLOAT_VALUE
946 if (CHECK_FLOAT_VALUE (mode, y.d, i))
950 /* Fail if truncation changed the value. */
951 if (y.d != t.d || y.d == 0.0)
955 if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
959 /* Output the reciprocal and return success flag. */
960 set_float_handler (NULL_PTR);
964 #endif /* no REAL_ARITHMETIC */
966 /* Split a tree IN into a constant and a variable part
967 that could be combined with CODE to make IN.
968 CODE must be a commutative arithmetic operation.
969 Store the constant part into *CONP and the variable in &VARP.
970 Return 1 if this was done; zero means the tree IN did not decompose
973 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
974 Therefore, we must tell the caller whether the variable part
975 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
976 The value stored is the coefficient for the variable term.
977 The constant term we return should always be added;
978 we negate it if necessary. */
981 split_tree (in, code, varp, conp, varsignp)
987 register tree outtype = TREE_TYPE (in);
991 /* Strip any conversions that don't change the machine mode. */
992 while ((TREE_CODE (in) == NOP_EXPR
993 || TREE_CODE (in) == CONVERT_EXPR)
994 && (TYPE_MODE (TREE_TYPE (in))
995 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
996 in = TREE_OPERAND (in, 0);
998 if (TREE_CODE (in) == code
999 || (! FLOAT_TYPE_P (TREE_TYPE (in))
1000 /* We can associate addition and subtraction together
1001 (even though the C standard doesn't say so)
1002 for integers because the value is not affected.
1003 For reals, the value might be affected, so we can't. */
1004 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
1005 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1007 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1008 if (code == INTEGER_CST)
1010 *conp = TREE_OPERAND (in, 0);
1011 *varp = TREE_OPERAND (in, 1);
1012 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1013 && TREE_TYPE (*varp) != outtype)
1014 *varp = convert (outtype, *varp);
1015 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1018 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1020 *conp = TREE_OPERAND (in, 1);
1021 *varp = TREE_OPERAND (in, 0);
1023 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1024 && TREE_TYPE (*varp) != outtype)
1025 *varp = convert (outtype, *varp);
1026 if (TREE_CODE (in) == MINUS_EXPR)
1028 /* If operation is subtraction and constant is second,
1029 must negate it to get an additive constant.
1030 And this cannot be done unless it is a manifest constant.
1031 It could also be the address of a static variable.
1032 We cannot negate that, so give up. */
1033 if (TREE_CODE (*conp) == INTEGER_CST)
1034 /* Subtracting from integer_zero_node loses for long long. */
1035 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1041 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1043 *conp = TREE_OPERAND (in, 0);
1044 *varp = TREE_OPERAND (in, 1);
1045 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1046 && TREE_TYPE (*varp) != outtype)
1047 *varp = convert (outtype, *varp);
1048 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1055 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1056 to produce a new constant.
1058 If NOTRUNC is nonzero, do not truncate the result to fit the data type.
1059 If FORSIZE is nonzero, compute overflow for unsigned types. */
1062 int_const_binop (code, arg1, arg2, notrunc, forsize)
1063 enum tree_code code;
1064 register tree arg1, arg2;
1065 int notrunc, forsize;
1067 HOST_WIDE_INT int1l, int1h, int2l, int2h;
1068 HOST_WIDE_INT low, hi;
1069 HOST_WIDE_INT garbagel, garbageh;
1071 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1073 int no_overflow = 0;
1075 int1l = TREE_INT_CST_LOW (arg1);
1076 int1h = TREE_INT_CST_HIGH (arg1);
1077 int2l = TREE_INT_CST_LOW (arg2);
1078 int2h = TREE_INT_CST_HIGH (arg2);
1083 low = int1l | int2l, hi = int1h | int2h;
1087 low = int1l ^ int2l, hi = int1h ^ int2h;
1091 low = int1l & int2l, hi = int1h & int2h;
1094 case BIT_ANDTC_EXPR:
1095 low = int1l & ~int2l, hi = int1h & ~int2h;
1101 /* It's unclear from the C standard whether shifts can overflow.
1102 The following code ignores overflow; perhaps a C standard
1103 interpretation ruling is needed. */
1104 lshift_double (int1l, int1h, int2l,
1105 TYPE_PRECISION (TREE_TYPE (arg1)),
1114 lrotate_double (int1l, int1h, int2l,
1115 TYPE_PRECISION (TREE_TYPE (arg1)),
1120 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1124 neg_double (int2l, int2h, &low, &hi);
1125 add_double (int1l, int1h, low, hi, &low, &hi);
1126 overflow = overflow_sum_sign (hi, int2h, int1h);
1130 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1133 case TRUNC_DIV_EXPR:
1134 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1135 case EXACT_DIV_EXPR:
1136 /* This is a shortcut for a common special case. */
1137 if (int2h == 0 && int2l > 0
1138 && ! TREE_CONSTANT_OVERFLOW (arg1)
1139 && ! TREE_CONSTANT_OVERFLOW (arg2)
1140 && int1h == 0 && int1l >= 0)
1142 if (code == CEIL_DIV_EXPR)
1144 low = int1l / int2l, hi = 0;
1148 /* ... fall through ... */
1150 case ROUND_DIV_EXPR:
1151 if (int2h == 0 && int2l == 1)
1153 low = int1l, hi = int1h;
1156 if (int1l == int2l && int1h == int2h
1157 && ! (int1l == 0 && int1h == 0))
1162 overflow = div_and_round_double (code, uns,
1163 int1l, int1h, int2l, int2h,
1164 &low, &hi, &garbagel, &garbageh);
1167 case TRUNC_MOD_EXPR:
1168 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1169 /* This is a shortcut for a common special case. */
1170 if (int2h == 0 && int2l > 0
1171 && ! TREE_CONSTANT_OVERFLOW (arg1)
1172 && ! TREE_CONSTANT_OVERFLOW (arg2)
1173 && int1h == 0 && int1l >= 0)
1175 if (code == CEIL_MOD_EXPR)
1177 low = int1l % int2l, hi = 0;
1181 /* ... fall through ... */
1183 case ROUND_MOD_EXPR:
1184 overflow = div_and_round_double (code, uns,
1185 int1l, int1h, int2l, int2h,
1186 &garbagel, &garbageh, &low, &hi);
1193 low = (((unsigned HOST_WIDE_INT) int1h
1194 < (unsigned HOST_WIDE_INT) int2h)
1195 || (((unsigned HOST_WIDE_INT) int1h
1196 == (unsigned HOST_WIDE_INT) int2h)
1197 && ((unsigned HOST_WIDE_INT) int1l
1198 < (unsigned HOST_WIDE_INT) int2l)));
1202 low = ((int1h < int2h)
1203 || ((int1h == int2h)
1204 && ((unsigned HOST_WIDE_INT) int1l
1205 < (unsigned HOST_WIDE_INT) int2l)));
1207 if (low == (code == MIN_EXPR))
1208 low = int1l, hi = int1h;
1210 low = int2l, hi = int2h;
1217 if (TREE_TYPE (arg1) == sizetype && hi == 0
1219 && (TYPE_MAX_VALUE (sizetype) == NULL
1220 || low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)))
1222 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1226 t = build_int_2 (low, hi);
1227 TREE_TYPE (t) = TREE_TYPE (arg1);
1231 = ((notrunc ? (!uns || forsize) && overflow
1232 : force_fit_type (t, (!uns || forsize) && overflow) && ! no_overflow)
1233 | TREE_OVERFLOW (arg1)
1234 | TREE_OVERFLOW (arg2));
1235 /* If we're doing a size calculation, unsigned arithmetic does overflow.
1236 So check if force_fit_type truncated the value. */
1238 && ! TREE_OVERFLOW (t)
1239 && (TREE_INT_CST_HIGH (t) != hi
1240 || TREE_INT_CST_LOW (t) != low))
1241 TREE_OVERFLOW (t) = 1;
1242 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1243 | TREE_CONSTANT_OVERFLOW (arg1)
1244 | TREE_CONSTANT_OVERFLOW (arg2));
1248 /* Combine two constants ARG1 and ARG2 under operation CODE
1249 to produce a new constant.
1250 We assume ARG1 and ARG2 have the same data type,
1251 or at least are the same kind of constant and the same machine mode.
1253 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1256 const_binop (code, arg1, arg2, notrunc)
1257 enum tree_code code;
1258 register tree arg1, arg2;
1261 STRIP_NOPS (arg1); STRIP_NOPS (arg2);
1263 if (TREE_CODE (arg1) == INTEGER_CST)
1264 return int_const_binop (code, arg1, arg2, notrunc, 0);
1266 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1267 if (TREE_CODE (arg1) == REAL_CST)
1272 REAL_VALUE_TYPE value;
1275 d1 = TREE_REAL_CST (arg1);
1276 d2 = TREE_REAL_CST (arg2);
1278 /* If either operand is a NaN, just return it. Otherwise, set up
1279 for floating-point trap; we return an overflow. */
1280 if (REAL_VALUE_ISNAN (d1))
1282 else if (REAL_VALUE_ISNAN (d2))
1284 else if (setjmp (float_error))
1286 t = copy_node (arg1);
1291 set_float_handler (float_error);
1293 #ifdef REAL_ARITHMETIC
1294 REAL_ARITHMETIC (value, code, d1, d2);
1311 #ifndef REAL_INFINITY
1320 value = MIN (d1, d2);
1324 value = MAX (d1, d2);
1330 #endif /* no REAL_ARITHMETIC */
1331 t = build_real (TREE_TYPE (arg1),
1332 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1334 set_float_handler (NULL_PTR);
1337 = (force_fit_type (t, overflow)
1338 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1339 TREE_CONSTANT_OVERFLOW (t)
1341 | TREE_CONSTANT_OVERFLOW (arg1)
1342 | TREE_CONSTANT_OVERFLOW (arg2);
1345 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1346 if (TREE_CODE (arg1) == COMPLEX_CST)
1348 register tree type = TREE_TYPE (arg1);
1349 register tree r1 = TREE_REALPART (arg1);
1350 register tree i1 = TREE_IMAGPART (arg1);
1351 register tree r2 = TREE_REALPART (arg2);
1352 register tree i2 = TREE_IMAGPART (arg2);
1358 t = build_complex (type,
1359 const_binop (PLUS_EXPR, r1, r2, notrunc),
1360 const_binop (PLUS_EXPR, i1, i2, notrunc));
1364 t = build_complex (type,
1365 const_binop (MINUS_EXPR, r1, r2, notrunc),
1366 const_binop (MINUS_EXPR, i1, i2, notrunc));
1370 t = build_complex (type,
1371 const_binop (MINUS_EXPR,
1372 const_binop (MULT_EXPR,
1374 const_binop (MULT_EXPR,
1377 const_binop (PLUS_EXPR,
1378 const_binop (MULT_EXPR,
1380 const_binop (MULT_EXPR,
1387 register tree magsquared
1388 = const_binop (PLUS_EXPR,
1389 const_binop (MULT_EXPR, r2, r2, notrunc),
1390 const_binop (MULT_EXPR, i2, i2, notrunc),
1393 t = build_complex (type,
1395 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1396 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1397 const_binop (PLUS_EXPR,
1398 const_binop (MULT_EXPR, r1, r2,
1400 const_binop (MULT_EXPR, i1, i2,
1403 magsquared, notrunc),
1405 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1406 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1407 const_binop (MINUS_EXPR,
1408 const_binop (MULT_EXPR, i1, r2,
1410 const_binop (MULT_EXPR, r1, i2,
1413 magsquared, notrunc));
1425 /* Return an INTEGER_CST with value V . The type is determined by bit_p:
1426 if it is zero, the type is taken from sizetype; if it is one, the type
1427 is taken from bitsizetype. */
1430 size_int_wide (number, high, bit_p)
1431 unsigned HOST_WIDE_INT number, high;
1434 /* Type-size nodes already made for small sizes. */
1435 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1][2];
1437 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high
1438 && size_table[number][bit_p] != 0)
1439 return size_table[number][bit_p];
1440 if (number < 2*HOST_BITS_PER_WIDE_INT + 1 && ! high)
1442 push_obstacks_nochange ();
1443 /* Make this a permanent node. */
1444 end_temporary_allocation ();
1445 t = build_int_2 (number, 0);
1446 TREE_TYPE (t) = sizetype_tab[bit_p];
1447 size_table[number][bit_p] = t;
1452 t = build_int_2 (number, high);
1453 TREE_TYPE (t) = sizetype_tab[bit_p];
1454 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1459 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1460 CODE is a tree code. Data type is taken from `sizetype',
1461 If the operands are constant, so is the result. */
1464 size_binop (code, arg0, arg1)
1465 enum tree_code code;
1468 /* Handle the special case of two integer constants faster. */
1469 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1471 /* And some specific cases even faster than that. */
1472 if (code == PLUS_EXPR && integer_zerop (arg0))
1474 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1475 && integer_zerop (arg1))
1477 else if (code == MULT_EXPR && integer_onep (arg0))
1480 /* Handle general case of two integer constants. */
1481 return int_const_binop (code, arg0, arg1, 0, 1);
1484 if (arg0 == error_mark_node || arg1 == error_mark_node)
1485 return error_mark_node;
1487 return fold (build (code, sizetype, arg0, arg1));
1490 /* Given T, a tree representing type conversion of ARG1, a constant,
1491 return a constant tree representing the result of conversion. */
1494 fold_convert (t, arg1)
1498 register tree type = TREE_TYPE (t);
1501 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1503 if (TREE_CODE (arg1) == INTEGER_CST)
1505 /* If we would build a constant wider than GCC supports,
1506 leave the conversion unfolded. */
1507 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1510 /* Given an integer constant, make new constant with new type,
1511 appropriately sign-extended or truncated. */
1512 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1513 TREE_INT_CST_HIGH (arg1));
1514 TREE_TYPE (t) = type;
1515 /* Indicate an overflow if (1) ARG1 already overflowed,
1516 or (2) force_fit_type indicates an overflow.
1517 Tell force_fit_type that an overflow has already occurred
1518 if ARG1 is a too-large unsigned value and T is signed.
1519 But don't indicate an overflow if converting a pointer. */
1521 = (TREE_OVERFLOW (arg1)
1522 || (force_fit_type (t,
1523 (TREE_INT_CST_HIGH (arg1) < 0
1524 && (TREE_UNSIGNED (type)
1525 < TREE_UNSIGNED (TREE_TYPE (arg1)))))
1526 && TREE_CODE (TREE_TYPE (arg1)) != POINTER_TYPE));
1527 TREE_CONSTANT_OVERFLOW (t)
1528 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1530 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1531 else if (TREE_CODE (arg1) == REAL_CST)
1533 /* Don't initialize these, use assignments.
1534 Initialized local aggregates don't work on old compilers. */
1538 tree type1 = TREE_TYPE (arg1);
1541 x = TREE_REAL_CST (arg1);
1542 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1544 no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
1545 if (!no_upper_bound)
1546 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1548 /* See if X will be in range after truncation towards 0.
1549 To compensate for truncation, move the bounds away from 0,
1550 but reject if X exactly equals the adjusted bounds. */
1551 #ifdef REAL_ARITHMETIC
1552 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1553 if (!no_upper_bound)
1554 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1557 if (!no_upper_bound)
1560 /* If X is a NaN, use zero instead and show we have an overflow.
1561 Otherwise, range check. */
1562 if (REAL_VALUE_ISNAN (x))
1563 overflow = 1, x = dconst0;
1564 else if (! (REAL_VALUES_LESS (l, x)
1566 && REAL_VALUES_LESS (x, u)))
1569 #ifndef REAL_ARITHMETIC
1571 HOST_WIDE_INT low, high;
1572 HOST_WIDE_INT half_word
1573 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1578 high = (HOST_WIDE_INT) (x / half_word / half_word);
1579 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1580 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1582 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1583 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1586 low = (HOST_WIDE_INT) x;
1587 if (TREE_REAL_CST (arg1) < 0)
1588 neg_double (low, high, &low, &high);
1589 t = build_int_2 (low, high);
1593 HOST_WIDE_INT low, high;
1594 REAL_VALUE_TO_INT (&low, &high, x);
1595 t = build_int_2 (low, high);
1598 TREE_TYPE (t) = type;
1600 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1601 TREE_CONSTANT_OVERFLOW (t)
1602 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1604 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1605 TREE_TYPE (t) = type;
1607 else if (TREE_CODE (type) == REAL_TYPE)
1609 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1610 if (TREE_CODE (arg1) == INTEGER_CST)
1611 return build_real_from_int_cst (type, arg1);
1612 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1613 if (TREE_CODE (arg1) == REAL_CST)
1615 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1618 TREE_TYPE (arg1) = type;
1621 else if (setjmp (float_error))
1624 t = copy_node (arg1);
1627 set_float_handler (float_error);
1629 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1630 TREE_REAL_CST (arg1)));
1631 set_float_handler (NULL_PTR);
1635 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1636 TREE_CONSTANT_OVERFLOW (t)
1637 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1641 TREE_CONSTANT (t) = 1;
1645 /* Return an expr equal to X but certainly not valid as an lvalue.
1646 Also make sure it is not valid as an null pointer constant. */
1654 /* These things are certainly not lvalues. */
1655 if (TREE_CODE (x) == NON_LVALUE_EXPR
1656 || TREE_CODE (x) == INTEGER_CST
1657 || TREE_CODE (x) == REAL_CST
1658 || TREE_CODE (x) == STRING_CST
1659 || TREE_CODE (x) == ADDR_EXPR)
1661 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1663 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1664 so convert_for_assignment won't strip it.
1665 This is so this 0 won't be treated as a null pointer constant. */
1666 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1667 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1673 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1674 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1678 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1679 Zero means allow extended lvalues. */
1681 int pedantic_lvalues;
1683 /* When pedantic, return an expr equal to X but certainly not valid as a
1684 pedantic lvalue. Otherwise, return X. */
1687 pedantic_non_lvalue (x)
1690 if (pedantic_lvalues)
1691 return non_lvalue (x);
1696 /* Given a tree comparison code, return the code that is the logical inverse
1697 of the given code. It is not safe to do this for floating-point
1698 comparisons, except for NE_EXPR and EQ_EXPR. */
1700 static enum tree_code
1701 invert_tree_comparison (code)
1702 enum tree_code code;
1723 /* Similar, but return the comparison that results if the operands are
1724 swapped. This is safe for floating-point. */
1726 static enum tree_code
1727 swap_tree_comparison (code)
1728 enum tree_code code;
1748 /* Return nonzero if CODE is a tree code that represents a truth value. */
1751 truth_value_p (code)
1752 enum tree_code code;
1754 return (TREE_CODE_CLASS (code) == '<'
1755 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1756 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1757 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1760 /* Return nonzero if two operands are necessarily equal.
1761 If ONLY_CONST is non-zero, only return non-zero for constants.
1762 This function tests whether the operands are indistinguishable;
1763 it does not test whether they are equal using C's == operation.
1764 The distinction is important for IEEE floating point, because
1765 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1766 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1769 operand_equal_p (arg0, arg1, only_const)
1773 /* If both types don't have the same signedness, then we can't consider
1774 them equal. We must check this before the STRIP_NOPS calls
1775 because they may change the signedness of the arguments. */
1776 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1782 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1783 /* This is needed for conversions and for COMPONENT_REF.
1784 Might as well play it safe and always test this. */
1785 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1788 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1789 We don't care about side effects in that case because the SAVE_EXPR
1790 takes care of that for us. In all other cases, two expressions are
1791 equal if they have no side effects. If we have two identical
1792 expressions with side effects that should be treated the same due
1793 to the only side effects being identical SAVE_EXPR's, that will
1794 be detected in the recursive calls below. */
1795 if (arg0 == arg1 && ! only_const
1796 && (TREE_CODE (arg0) == SAVE_EXPR
1797 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1800 /* Next handle constant cases, those for which we can return 1 even
1801 if ONLY_CONST is set. */
1802 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1803 switch (TREE_CODE (arg0))
1806 return (! TREE_CONSTANT_OVERFLOW (arg0)
1807 && ! TREE_CONSTANT_OVERFLOW (arg1)
1808 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1809 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
1812 return (! TREE_CONSTANT_OVERFLOW (arg0)
1813 && ! TREE_CONSTANT_OVERFLOW (arg1)
1814 && REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
1815 TREE_REAL_CST (arg1)));
1818 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1820 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1824 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1825 && ! strncmp (TREE_STRING_POINTER (arg0),
1826 TREE_STRING_POINTER (arg1),
1827 TREE_STRING_LENGTH (arg0)));
1830 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1839 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1842 /* Two conversions are equal only if signedness and modes match. */
1843 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1844 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1845 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1848 return operand_equal_p (TREE_OPERAND (arg0, 0),
1849 TREE_OPERAND (arg1, 0), 0);
1853 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1854 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1858 /* For commutative ops, allow the other order. */
1859 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1860 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1861 || TREE_CODE (arg0) == BIT_IOR_EXPR
1862 || TREE_CODE (arg0) == BIT_XOR_EXPR
1863 || TREE_CODE (arg0) == BIT_AND_EXPR
1864 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1865 && operand_equal_p (TREE_OPERAND (arg0, 0),
1866 TREE_OPERAND (arg1, 1), 0)
1867 && operand_equal_p (TREE_OPERAND (arg0, 1),
1868 TREE_OPERAND (arg1, 0), 0));
1871 switch (TREE_CODE (arg0))
1874 return operand_equal_p (TREE_OPERAND (arg0, 0),
1875 TREE_OPERAND (arg1, 0), 0);
1879 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1880 TREE_OPERAND (arg1, 0), 0)
1881 && operand_equal_p (TREE_OPERAND (arg0, 1),
1882 TREE_OPERAND (arg1, 1), 0));
1885 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1886 TREE_OPERAND (arg1, 0), 0)
1887 && operand_equal_p (TREE_OPERAND (arg0, 1),
1888 TREE_OPERAND (arg1, 1), 0)
1889 && operand_equal_p (TREE_OPERAND (arg0, 2),
1890 TREE_OPERAND (arg1, 2), 0));
1900 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1901 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1903 When in doubt, return 0. */
1906 operand_equal_for_comparison_p (arg0, arg1, other)
1910 int unsignedp1, unsignedpo;
1911 tree primarg1, primother;
1912 unsigned correct_width;
1914 if (operand_equal_p (arg0, arg1, 0))
1917 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1918 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1921 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1922 actual comparison operand, ARG0.
1924 First throw away any conversions to wider types
1925 already present in the operands. */
1927 primarg1 = get_narrower (arg1, &unsignedp1);
1928 primother = get_narrower (other, &unsignedpo);
1930 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1931 if (unsignedp1 == unsignedpo
1932 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1933 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1935 tree type = TREE_TYPE (arg0);
1937 /* Make sure shorter operand is extended the right way
1938 to match the longer operand. */
1939 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1940 TREE_TYPE (primarg1)),
1943 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1950 /* See if ARG is an expression that is either a comparison or is performing
1951 arithmetic on comparisons. The comparisons must only be comparing
1952 two different values, which will be stored in *CVAL1 and *CVAL2; if
1953 they are non-zero it means that some operands have already been found.
1954 No variables may be used anywhere else in the expression except in the
1955 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1956 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1958 If this is true, return 1. Otherwise, return zero. */
1961 twoval_comparison_p (arg, cval1, cval2, save_p)
1963 tree *cval1, *cval2;
1966 enum tree_code code = TREE_CODE (arg);
1967 char class = TREE_CODE_CLASS (code);
1969 /* We can handle some of the 'e' cases here. */
1970 if (class == 'e' && code == TRUTH_NOT_EXPR)
1972 else if (class == 'e'
1973 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1974 || code == COMPOUND_EXPR))
1977 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1978 the expression. There may be no way to make this work, but it needs
1979 to be looked at again for 2.6. */
1981 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1983 /* If we've already found a CVAL1 or CVAL2, this expression is
1984 two complex to handle. */
1985 if (*cval1 || *cval2)
1996 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
1999 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
2000 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2001 cval1, cval2, save_p));
2007 if (code == COND_EXPR)
2008 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
2009 cval1, cval2, save_p)
2010 && twoval_comparison_p (TREE_OPERAND (arg, 1),
2011 cval1, cval2, save_p)
2012 && twoval_comparison_p (TREE_OPERAND (arg, 2),
2013 cval1, cval2, save_p));
2017 /* First see if we can handle the first operand, then the second. For
2018 the second operand, we know *CVAL1 can't be zero. It must be that
2019 one side of the comparison is each of the values; test for the
2020 case where this isn't true by failing if the two operands
2023 if (operand_equal_p (TREE_OPERAND (arg, 0),
2024 TREE_OPERAND (arg, 1), 0))
2028 *cval1 = TREE_OPERAND (arg, 0);
2029 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
2031 else if (*cval2 == 0)
2032 *cval2 = TREE_OPERAND (arg, 0);
2033 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
2038 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
2040 else if (*cval2 == 0)
2041 *cval2 = TREE_OPERAND (arg, 1);
2042 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2054 /* ARG is a tree that is known to contain just arithmetic operations and
2055 comparisons. Evaluate the operations in the tree substituting NEW0 for
2056 any occurrence of OLD0 as an operand of a comparison and likewise for
2060 eval_subst (arg, old0, new0, old1, new1)
2062 tree old0, new0, old1, new1;
2064 tree type = TREE_TYPE (arg);
2065 enum tree_code code = TREE_CODE (arg);
2066 char class = TREE_CODE_CLASS (code);
2068 /* We can handle some of the 'e' cases here. */
2069 if (class == 'e' && code == TRUTH_NOT_EXPR)
2071 else if (class == 'e'
2072 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2078 return fold (build1 (code, type,
2079 eval_subst (TREE_OPERAND (arg, 0),
2080 old0, new0, old1, new1)));
2083 return fold (build (code, type,
2084 eval_subst (TREE_OPERAND (arg, 0),
2085 old0, new0, old1, new1),
2086 eval_subst (TREE_OPERAND (arg, 1),
2087 old0, new0, old1, new1)));
2093 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2096 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2099 return fold (build (code, type,
2100 eval_subst (TREE_OPERAND (arg, 0),
2101 old0, new0, old1, new1),
2102 eval_subst (TREE_OPERAND (arg, 1),
2103 old0, new0, old1, new1),
2104 eval_subst (TREE_OPERAND (arg, 2),
2105 old0, new0, old1, new1)));
2109 /* fall through (???) */
2113 tree arg0 = TREE_OPERAND (arg, 0);
2114 tree arg1 = TREE_OPERAND (arg, 1);
2116 /* We need to check both for exact equality and tree equality. The
2117 former will be true if the operand has a side-effect. In that
2118 case, we know the operand occurred exactly once. */
2120 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2122 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2125 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2127 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2130 return fold (build (code, type, arg0, arg1));
2138 /* Return a tree for the case when the result of an expression is RESULT
2139 converted to TYPE and OMITTED was previously an operand of the expression
2140 but is now not needed (e.g., we folded OMITTED * 0).
2142 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2143 the conversion of RESULT to TYPE. */
2146 omit_one_operand (type, result, omitted)
2147 tree type, result, omitted;
2149 tree t = convert (type, result);
2151 if (TREE_SIDE_EFFECTS (omitted))
2152 return build (COMPOUND_EXPR, type, omitted, t);
2154 return non_lvalue (t);
2157 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2160 pedantic_omit_one_operand (type, result, omitted)
2161 tree type, result, omitted;
2163 tree t = convert (type, result);
2165 if (TREE_SIDE_EFFECTS (omitted))
2166 return build (COMPOUND_EXPR, type, omitted, t);
2168 return pedantic_non_lvalue (t);
2173 /* Return a simplified tree node for the truth-negation of ARG. This
2174 never alters ARG itself. We assume that ARG is an operation that
2175 returns a truth value (0 or 1). */
2178 invert_truthvalue (arg)
2181 tree type = TREE_TYPE (arg);
2182 enum tree_code code = TREE_CODE (arg);
2184 if (code == ERROR_MARK)
2187 /* If this is a comparison, we can simply invert it, except for
2188 floating-point non-equality comparisons, in which case we just
2189 enclose a TRUTH_NOT_EXPR around what we have. */
2191 if (TREE_CODE_CLASS (code) == '<')
2193 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2194 && code != NE_EXPR && code != EQ_EXPR)
2195 return build1 (TRUTH_NOT_EXPR, type, arg);
2197 return build (invert_tree_comparison (code), type,
2198 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2204 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2205 && TREE_INT_CST_HIGH (arg) == 0, 0));
2207 case TRUTH_AND_EXPR:
2208 return build (TRUTH_OR_EXPR, type,
2209 invert_truthvalue (TREE_OPERAND (arg, 0)),
2210 invert_truthvalue (TREE_OPERAND (arg, 1)));
2213 return build (TRUTH_AND_EXPR, type,
2214 invert_truthvalue (TREE_OPERAND (arg, 0)),
2215 invert_truthvalue (TREE_OPERAND (arg, 1)));
2217 case TRUTH_XOR_EXPR:
2218 /* Here we can invert either operand. We invert the first operand
2219 unless the second operand is a TRUTH_NOT_EXPR in which case our
2220 result is the XOR of the first operand with the inside of the
2221 negation of the second operand. */
2223 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2224 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2225 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2227 return build (TRUTH_XOR_EXPR, type,
2228 invert_truthvalue (TREE_OPERAND (arg, 0)),
2229 TREE_OPERAND (arg, 1));
2231 case TRUTH_ANDIF_EXPR:
2232 return build (TRUTH_ORIF_EXPR, type,
2233 invert_truthvalue (TREE_OPERAND (arg, 0)),
2234 invert_truthvalue (TREE_OPERAND (arg, 1)));
2236 case TRUTH_ORIF_EXPR:
2237 return build (TRUTH_ANDIF_EXPR, type,
2238 invert_truthvalue (TREE_OPERAND (arg, 0)),
2239 invert_truthvalue (TREE_OPERAND (arg, 1)));
2241 case TRUTH_NOT_EXPR:
2242 return TREE_OPERAND (arg, 0);
2245 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2246 invert_truthvalue (TREE_OPERAND (arg, 1)),
2247 invert_truthvalue (TREE_OPERAND (arg, 2)));
2250 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2251 invert_truthvalue (TREE_OPERAND (arg, 1)));
2253 case NON_LVALUE_EXPR:
2254 return invert_truthvalue (TREE_OPERAND (arg, 0));
2259 return build1 (TREE_CODE (arg), type,
2260 invert_truthvalue (TREE_OPERAND (arg, 0)));
2263 if (!integer_onep (TREE_OPERAND (arg, 1)))
2265 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2268 return build1 (TRUTH_NOT_EXPR, type, arg);
2270 case CLEANUP_POINT_EXPR:
2271 return build1 (CLEANUP_POINT_EXPR, type,
2272 invert_truthvalue (TREE_OPERAND (arg, 0)));
2277 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2279 return build1 (TRUTH_NOT_EXPR, type, arg);
2282 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2283 operands are another bit-wise operation with a common input. If so,
2284 distribute the bit operations to save an operation and possibly two if
2285 constants are involved. For example, convert
2286 (A | B) & (A | C) into A | (B & C)
2287 Further simplification will occur if B and C are constants.
2289 If this optimization cannot be done, 0 will be returned. */
2292 distribute_bit_expr (code, type, arg0, arg1)
2293 enum tree_code code;
2300 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2301 || TREE_CODE (arg0) == code
2302 || (TREE_CODE (arg0) != BIT_AND_EXPR
2303 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2306 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2308 common = TREE_OPERAND (arg0, 0);
2309 left = TREE_OPERAND (arg0, 1);
2310 right = TREE_OPERAND (arg1, 1);
2312 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2314 common = TREE_OPERAND (arg0, 0);
2315 left = TREE_OPERAND (arg0, 1);
2316 right = TREE_OPERAND (arg1, 0);
2318 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2320 common = TREE_OPERAND (arg0, 1);
2321 left = TREE_OPERAND (arg0, 0);
2322 right = TREE_OPERAND (arg1, 1);
2324 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2326 common = TREE_OPERAND (arg0, 1);
2327 left = TREE_OPERAND (arg0, 0);
2328 right = TREE_OPERAND (arg1, 0);
2333 return fold (build (TREE_CODE (arg0), type, common,
2334 fold (build (code, type, left, right))));
2337 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2338 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2341 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2344 int bitsize, bitpos;
2347 tree result = build (BIT_FIELD_REF, type, inner,
2348 size_int (bitsize), bitsize_int (bitpos, 0L));
2350 TREE_UNSIGNED (result) = unsignedp;
2355 /* Optimize a bit-field compare.
2357 There are two cases: First is a compare against a constant and the
2358 second is a comparison of two items where the fields are at the same
2359 bit position relative to the start of a chunk (byte, halfword, word)
2360 large enough to contain it. In these cases we can avoid the shift
2361 implicit in bitfield extractions.
2363 For constants, we emit a compare of the shifted constant with the
2364 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2365 compared. For two fields at the same position, we do the ANDs with the
2366 similar mask and compare the result of the ANDs.
2368 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2369 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2370 are the left and right operands of the comparison, respectively.
2372 If the optimization described above can be done, we return the resulting
2373 tree. Otherwise we return zero. */
2376 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2377 enum tree_code code;
2381 int lbitpos, lbitsize, rbitpos, rbitsize;
2382 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2383 tree type = TREE_TYPE (lhs);
2384 tree signed_type, unsigned_type;
2385 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2386 enum machine_mode lmode, rmode, lnmode, rnmode;
2387 int lunsignedp, runsignedp;
2388 int lvolatilep = 0, rvolatilep = 0;
2390 tree linner, rinner;
2394 /* Get all the information about the extractions being done. If the bit size
2395 if the same as the size of the underlying object, we aren't doing an
2396 extraction at all and so can do nothing. */
2397 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2398 &lunsignedp, &lvolatilep, &alignment);
2399 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2405 /* If this is not a constant, we can only do something if bit positions,
2406 sizes, and signedness are the same. */
2407 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2408 &runsignedp, &rvolatilep, &alignment);
2410 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2411 || lunsignedp != runsignedp || offset != 0)
2415 /* See if we can find a mode to refer to this field. We should be able to,
2416 but fail if we can't. */
2417 lnmode = get_best_mode (lbitsize, lbitpos,
2418 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2420 if (lnmode == VOIDmode)
2423 /* Set signed and unsigned types of the precision of this mode for the
2425 signed_type = type_for_mode (lnmode, 0);
2426 unsigned_type = type_for_mode (lnmode, 1);
2430 rnmode = get_best_mode (rbitsize, rbitpos,
2431 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2433 if (rnmode == VOIDmode)
2437 /* Compute the bit position and size for the new reference and our offset
2438 within it. If the new reference is the same size as the original, we
2439 won't optimize anything, so return zero. */
2440 lnbitsize = GET_MODE_BITSIZE (lnmode);
2441 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2442 lbitpos -= lnbitpos;
2443 if (lnbitsize == lbitsize)
2448 rnbitsize = GET_MODE_BITSIZE (rnmode);
2449 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2450 rbitpos -= rnbitpos;
2451 if (rnbitsize == rbitsize)
2455 if (BYTES_BIG_ENDIAN)
2456 lbitpos = lnbitsize - lbitsize - lbitpos;
2458 /* Make the mask to be used against the extracted field. */
2459 mask = build_int_2 (~0, ~0);
2460 TREE_TYPE (mask) = unsigned_type;
2461 force_fit_type (mask, 0);
2462 mask = convert (unsigned_type, mask);
2463 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2464 mask = const_binop (RSHIFT_EXPR, mask,
2465 size_int (lnbitsize - lbitsize - lbitpos), 0);
2468 /* If not comparing with constant, just rework the comparison
2470 return build (code, compare_type,
2471 build (BIT_AND_EXPR, unsigned_type,
2472 make_bit_field_ref (linner, unsigned_type,
2473 lnbitsize, lnbitpos, 1),
2475 build (BIT_AND_EXPR, unsigned_type,
2476 make_bit_field_ref (rinner, unsigned_type,
2477 rnbitsize, rnbitpos, 1),
2480 /* Otherwise, we are handling the constant case. See if the constant is too
2481 big for the field. Warn and return a tree of for 0 (false) if so. We do
2482 this not only for its own sake, but to avoid having to test for this
2483 error case below. If we didn't, we might generate wrong code.
2485 For unsigned fields, the constant shifted right by the field length should
2486 be all zero. For signed fields, the high-order bits should agree with
2491 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2492 convert (unsigned_type, rhs),
2493 size_int (lbitsize), 0)))
2495 warning ("comparison is always %s due to width of bitfield",
2496 code == NE_EXPR ? "one" : "zero");
2497 return convert (compare_type,
2499 ? integer_one_node : integer_zero_node));
2504 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2505 size_int (lbitsize - 1), 0);
2506 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2508 warning ("comparison is always %s due to width of bitfield",
2509 code == NE_EXPR ? "one" : "zero");
2510 return convert (compare_type,
2512 ? integer_one_node : integer_zero_node));
2516 /* Single-bit compares should always be against zero. */
2517 if (lbitsize == 1 && ! integer_zerop (rhs))
2519 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2520 rhs = convert (type, integer_zero_node);
2523 /* Make a new bitfield reference, shift the constant over the
2524 appropriate number of bits and mask it with the computed mask
2525 (in case this was a signed field). If we changed it, make a new one. */
2526 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2529 TREE_SIDE_EFFECTS (lhs) = 1;
2530 TREE_THIS_VOLATILE (lhs) = 1;
2533 rhs = fold (const_binop (BIT_AND_EXPR,
2534 const_binop (LSHIFT_EXPR,
2535 convert (unsigned_type, rhs),
2536 size_int (lbitpos), 0),
2539 return build (code, compare_type,
2540 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2544 /* Subroutine for fold_truthop: decode a field reference.
2546 If EXP is a comparison reference, we return the innermost reference.
2548 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2549 set to the starting bit number.
2551 If the innermost field can be completely contained in a mode-sized
2552 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2554 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2555 otherwise it is not changed.
2557 *PUNSIGNEDP is set to the signedness of the field.
2559 *PMASK is set to the mask used. This is either contained in a
2560 BIT_AND_EXPR or derived from the width of the field.
2562 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2564 Return 0 if this is not a component reference or is one that we can't
2565 do anything with. */
2568 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2569 pvolatilep, pmask, pand_mask)
2571 int *pbitsize, *pbitpos;
2572 enum machine_mode *pmode;
2573 int *punsignedp, *pvolatilep;
2578 tree mask, inner, offset;
2583 /* All the optimizations using this function assume integer fields.
2584 There are problems with FP fields since the type_for_size call
2585 below can fail for, e.g., XFmode. */
2586 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2591 if (TREE_CODE (exp) == BIT_AND_EXPR)
2593 and_mask = TREE_OPERAND (exp, 1);
2594 exp = TREE_OPERAND (exp, 0);
2595 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2596 if (TREE_CODE (and_mask) != INTEGER_CST)
2601 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2602 punsignedp, pvolatilep, &alignment);
2603 if ((inner == exp && and_mask == 0)
2604 || *pbitsize < 0 || offset != 0)
2607 /* Compute the mask to access the bitfield. */
2608 unsigned_type = type_for_size (*pbitsize, 1);
2609 precision = TYPE_PRECISION (unsigned_type);
2611 mask = build_int_2 (~0, ~0);
2612 TREE_TYPE (mask) = unsigned_type;
2613 force_fit_type (mask, 0);
2614 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2615 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2617 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2619 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2620 convert (unsigned_type, and_mask), mask));
2623 *pand_mask = and_mask;
2627 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2631 all_ones_mask_p (mask, size)
2635 tree type = TREE_TYPE (mask);
2636 int precision = TYPE_PRECISION (type);
2639 tmask = build_int_2 (~0, ~0);
2640 TREE_TYPE (tmask) = signed_type (type);
2641 force_fit_type (tmask, 0);
2643 tree_int_cst_equal (mask,
2644 const_binop (RSHIFT_EXPR,
2645 const_binop (LSHIFT_EXPR, tmask,
2646 size_int (precision - size),
2648 size_int (precision - size), 0));
2651 /* Subroutine for fold_truthop: determine if an operand is simple enough
2652 to be evaluated unconditionally. */
2655 simple_operand_p (exp)
2658 /* Strip any conversions that don't change the machine mode. */
2659 while ((TREE_CODE (exp) == NOP_EXPR
2660 || TREE_CODE (exp) == CONVERT_EXPR)
2661 && (TYPE_MODE (TREE_TYPE (exp))
2662 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2663 exp = TREE_OPERAND (exp, 0);
2665 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2666 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2667 && ! TREE_ADDRESSABLE (exp)
2668 && ! TREE_THIS_VOLATILE (exp)
2669 && ! DECL_NONLOCAL (exp)
2670 /* Don't regard global variables as simple. They may be
2671 allocated in ways unknown to the compiler (shared memory,
2672 #pragma weak, etc). */
2673 && ! TREE_PUBLIC (exp)
2674 && ! DECL_EXTERNAL (exp)
2675 /* Loading a static variable is unduly expensive, but global
2676 registers aren't expensive. */
2677 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2680 /* The following functions are subroutines to fold_range_test and allow it to
2681 try to change a logical combination of comparisons into a range test.
2684 X == 2 && X == 3 && X == 4 && X == 5
2688 (unsigned) (X - 2) <= 3
2690 We describe each set of comparisons as being either inside or outside
2691 a range, using a variable named like IN_P, and then describe the
2692 range with a lower and upper bound. If one of the bounds is omitted,
2693 it represents either the highest or lowest value of the type.
2695 In the comments below, we represent a range by two numbers in brackets
2696 preceded by a "+" to designate being inside that range, or a "-" to
2697 designate being outside that range, so the condition can be inverted by
2698 flipping the prefix. An omitted bound is represented by a "-". For
2699 example, "- [-, 10]" means being outside the range starting at the lowest
2700 possible value and ending at 10, in other words, being greater than 10.
2701 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2704 We set up things so that the missing bounds are handled in a consistent
2705 manner so neither a missing bound nor "true" and "false" need to be
2706 handled using a special case. */
2708 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2709 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2710 and UPPER1_P are nonzero if the respective argument is an upper bound
2711 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2712 must be specified for a comparison. ARG1 will be converted to ARG0's
2713 type if both are specified. */
2716 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2717 enum tree_code code;
2720 int upper0_p, upper1_p;
2726 /* If neither arg represents infinity, do the normal operation.
2727 Else, if not a comparison, return infinity. Else handle the special
2728 comparison rules. Note that most of the cases below won't occur, but
2729 are handled for consistency. */
2731 if (arg0 != 0 && arg1 != 0)
2733 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2734 arg0, convert (TREE_TYPE (arg0), arg1)));
2736 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2739 if (TREE_CODE_CLASS (code) != '<')
2742 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2743 for neither. Then compute our result treating them as never equal
2744 and comparing bounds to non-bounds as above. */
2745 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2746 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2749 case EQ_EXPR: case NE_EXPR:
2750 result = (code == NE_EXPR);
2752 case LT_EXPR: case LE_EXPR:
2753 result = sgn0 < sgn1;
2755 case GT_EXPR: case GE_EXPR:
2756 result = sgn0 > sgn1;
2762 return convert (type, result ? integer_one_node : integer_zero_node);
2765 /* Given EXP, a logical expression, set the range it is testing into
2766 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2767 actually being tested. *PLOW and *PHIGH will have be made the same type
2768 as the returned expression. If EXP is not a comparison, we will most
2769 likely not be returning a useful value and range. */
2772 make_range (exp, pin_p, plow, phigh)
2777 enum tree_code code;
2778 tree arg0, arg1, type;
2780 tree low, high, n_low, n_high;
2782 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2783 and see if we can refine the range. Some of the cases below may not
2784 happen, but it doesn't seem worth worrying about this. We "continue"
2785 the outer loop when we've changed something; otherwise we "break"
2786 the switch, which will "break" the while. */
2788 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2792 code = TREE_CODE (exp);
2793 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2794 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2795 || TREE_CODE_CLASS (code) == '2')
2796 type = TREE_TYPE (arg0);
2800 case TRUTH_NOT_EXPR:
2801 in_p = ! in_p, exp = arg0;
2804 case EQ_EXPR: case NE_EXPR:
2805 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2806 /* We can only do something if the range is testing for zero
2807 and if the second operand is an integer constant. Note that
2808 saying something is "in" the range we make is done by
2809 complementing IN_P since it will set in the initial case of
2810 being not equal to zero; "out" is leaving it alone. */
2811 if (low == 0 || high == 0
2812 || ! integer_zerop (low) || ! integer_zerop (high)
2813 || TREE_CODE (arg1) != INTEGER_CST)
2818 case NE_EXPR: /* - [c, c] */
2821 case EQ_EXPR: /* + [c, c] */
2822 in_p = ! in_p, low = high = arg1;
2824 case GT_EXPR: /* - [-, c] */
2825 low = 0, high = arg1;
2827 case GE_EXPR: /* + [c, -] */
2828 in_p = ! in_p, low = arg1, high = 0;
2830 case LT_EXPR: /* - [c, -] */
2831 low = arg1, high = 0;
2833 case LE_EXPR: /* + [-, c] */
2834 in_p = ! in_p, low = 0, high = arg1;
2842 /* If this is an unsigned comparison, we also know that EXP is
2843 greater than or equal to zero. We base the range tests we make
2844 on that fact, so we record it here so we can parse existing
2846 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2848 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2849 1, convert (type, integer_zero_node),
2853 in_p = n_in_p, low = n_low, high = n_high;
2855 /* If the high bound is missing, reverse the range so it
2856 goes from zero to the low bound minus 1. */
2860 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2861 integer_one_node, 0);
2862 low = convert (type, integer_zero_node);
2868 /* (-x) IN [a,b] -> x in [-b, -a] */
2869 n_low = range_binop (MINUS_EXPR, type,
2870 convert (type, integer_zero_node), 0, high, 1);
2871 n_high = range_binop (MINUS_EXPR, type,
2872 convert (type, integer_zero_node), 0, low, 0);
2873 low = n_low, high = n_high;
2879 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2880 convert (type, integer_one_node));
2883 case PLUS_EXPR: case MINUS_EXPR:
2884 if (TREE_CODE (arg1) != INTEGER_CST)
2887 /* If EXP is signed, any overflow in the computation is undefined,
2888 so we don't worry about it so long as our computations on
2889 the bounds don't overflow. For unsigned, overflow is defined
2890 and this is exactly the right thing. */
2891 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2892 type, low, 0, arg1, 0);
2893 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2894 type, high, 1, arg1, 0);
2895 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2896 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2899 /* Check for an unsigned range which has wrapped around the maximum
2900 value thus making n_high < n_low, and normalize it. */
2901 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2903 low = range_binop (PLUS_EXPR, type, n_high, 0,
2904 integer_one_node, 0);
2905 high = range_binop (MINUS_EXPR, type, n_low, 0,
2906 integer_one_node, 0);
2910 low = n_low, high = n_high;
2915 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2916 if (! INTEGRAL_TYPE_P (type)
2917 || (low != 0 && ! int_fits_type_p (low, type))
2918 || (high != 0 && ! int_fits_type_p (high, type)))
2921 n_low = low, n_high = high;
2924 n_low = convert (type, n_low);
2927 n_high = convert (type, n_high);
2929 /* If we're converting from an unsigned to a signed type,
2930 we will be doing the comparison as unsigned. The tests above
2931 have already verified that LOW and HIGH are both positive.
2933 So we have to make sure that the original unsigned value will
2934 be interpreted as positive. */
2935 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
2937 tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
2940 /* A range without an upper bound is, naturally, unbounded.
2941 Since convert would have cropped a very large value, use
2942 the max value for the destination type. */
2944 high_positive = TYPE_MAX_VALUE (equiv_type);
2947 high_positive = TYPE_MAX_VALUE (type);
2951 high_positive = fold (build (RSHIFT_EXPR, type,
2952 convert (type, high_positive),
2953 convert (type, integer_one_node)));
2955 /* If the low bound is specified, "and" the range with the
2956 range for which the original unsigned value will be
2960 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2962 1, convert (type, integer_zero_node),
2966 in_p = (n_in_p == in_p);
2970 /* Otherwise, "or" the range with the range of the input
2971 that will be interpreted as negative. */
2972 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2974 1, convert (type, integer_zero_node),
2978 in_p = (in_p != n_in_p);
2983 low = n_low, high = n_high;
2993 /* If EXP is a constant, we can evaluate whether this is true or false. */
2994 if (TREE_CODE (exp) == INTEGER_CST)
2996 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2998 && integer_onep (range_binop (LE_EXPR, integer_type_node,
3004 *pin_p = in_p, *plow = low, *phigh = high;
3008 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
3009 type, TYPE, return an expression to test if EXP is in (or out of, depending
3010 on IN_P) the range. */
3013 build_range_check (type, exp, in_p, low, high)
3019 tree etype = TREE_TYPE (exp);
3023 && (0 != (value = build_range_check (type, exp, 1, low, high))))
3024 return invert_truthvalue (value);
3026 else if (low == 0 && high == 0)
3027 return convert (type, integer_one_node);
3030 return fold (build (LE_EXPR, type, exp, high));
3033 return fold (build (GE_EXPR, type, exp, low));
3035 else if (operand_equal_p (low, high, 0))
3036 return fold (build (EQ_EXPR, type, exp, low));
3038 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
3039 return build_range_check (type, exp, 1, 0, high);
3041 else if (integer_zerop (low))
3043 utype = unsigned_type (etype);
3044 return build_range_check (type, convert (utype, exp), 1, 0,
3045 convert (utype, high));
3048 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
3049 && ! TREE_OVERFLOW (value))
3050 return build_range_check (type,
3051 fold (build (MINUS_EXPR, etype, exp, low)),
3052 1, convert (etype, integer_zero_node), value);
3057 /* Given two ranges, see if we can merge them into one. Return 1 if we
3058 can, 0 if we can't. Set the output range into the specified parameters. */
3061 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
3065 tree low0, high0, low1, high1;
3073 int lowequal = ((low0 == 0 && low1 == 0)
3074 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3075 low0, 0, low1, 0)));
3076 int highequal = ((high0 == 0 && high1 == 0)
3077 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3078 high0, 1, high1, 1)));
3080 /* Make range 0 be the range that starts first, or ends last if they
3081 start at the same value. Swap them if it isn't. */
3082 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3085 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3086 high1, 1, high0, 1))))
3088 temp = in0_p, in0_p = in1_p, in1_p = temp;
3089 tem = low0, low0 = low1, low1 = tem;
3090 tem = high0, high0 = high1, high1 = tem;
3093 /* Now flag two cases, whether the ranges are disjoint or whether the
3094 second range is totally subsumed in the first. Note that the tests
3095 below are simplified by the ones above. */
3096 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3097 high0, 1, low1, 0));
3098 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3099 high1, 1, high0, 1));
3101 /* We now have four cases, depending on whether we are including or
3102 excluding the two ranges. */
3105 /* If they don't overlap, the result is false. If the second range
3106 is a subset it is the result. Otherwise, the range is from the start
3107 of the second to the end of the first. */
3109 in_p = 0, low = high = 0;
3111 in_p = 1, low = low1, high = high1;
3113 in_p = 1, low = low1, high = high0;
3116 else if (in0_p && ! in1_p)
3118 /* If they don't overlap, the result is the first range. If they are
3119 equal, the result is false. If the second range is a subset of the
3120 first, and the ranges begin at the same place, we go from just after
3121 the end of the first range to the end of the second. If the second
3122 range is not a subset of the first, or if it is a subset and both
3123 ranges end at the same place, the range starts at the start of the
3124 first range and ends just before the second range.
3125 Otherwise, we can't describe this as a single range. */
3127 in_p = 1, low = low0, high = high0;
3128 else if (lowequal && highequal)
3129 in_p = 0, low = high = 0;
3130 else if (subset && lowequal)
3132 in_p = 1, high = high0;
3133 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3134 integer_one_node, 0);
3136 else if (! subset || highequal)
3138 in_p = 1, low = low0;
3139 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3140 integer_one_node, 0);
3146 else if (! in0_p && in1_p)
3148 /* If they don't overlap, the result is the second range. If the second
3149 is a subset of the first, the result is false. Otherwise,
3150 the range starts just after the first range and ends at the
3151 end of the second. */
3153 in_p = 1, low = low1, high = high1;
3155 in_p = 0, low = high = 0;
3158 in_p = 1, high = high1;
3159 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3160 integer_one_node, 0);
3166 /* The case where we are excluding both ranges. Here the complex case
3167 is if they don't overlap. In that case, the only time we have a
3168 range is if they are adjacent. If the second is a subset of the
3169 first, the result is the first. Otherwise, the range to exclude
3170 starts at the beginning of the first range and ends at the end of the
3174 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3175 range_binop (PLUS_EXPR, NULL_TREE,
3177 integer_one_node, 1),
3179 in_p = 0, low = low0, high = high1;
3184 in_p = 0, low = low0, high = high0;
3186 in_p = 0, low = low0, high = high1;
3189 *pin_p = in_p, *plow = low, *phigh = high;
3193 /* EXP is some logical combination of boolean tests. See if we can
3194 merge it into some range test. Return the new tree if so. */
3197 fold_range_test (exp)
3200 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3201 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3202 int in0_p, in1_p, in_p;
3203 tree low0, low1, low, high0, high1, high;
3204 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3205 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3208 /* If this is an OR operation, invert both sides; we will invert
3209 again at the end. */
3211 in0_p = ! in0_p, in1_p = ! in1_p;
3213 /* If both expressions are the same, if we can merge the ranges, and we
3214 can build the range test, return it or it inverted. If one of the
3215 ranges is always true or always false, consider it to be the same
3216 expression as the other. */
3217 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3218 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3220 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3222 : rhs != 0 ? rhs : integer_zero_node,
3224 return or_op ? invert_truthvalue (tem) : tem;
3226 /* On machines where the branch cost is expensive, if this is a
3227 short-circuited branch and the underlying object on both sides
3228 is the same, make a non-short-circuit operation. */
3229 else if (BRANCH_COST >= 2
3230 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3231 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3232 && operand_equal_p (lhs, rhs, 0))
3234 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3235 unless we are at top level, in which case we can't do this. */
3236 if (simple_operand_p (lhs))
3237 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3238 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3239 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3240 TREE_OPERAND (exp, 1));
3242 else if (current_function_decl != 0)
3244 tree common = save_expr (lhs);
3246 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3247 or_op ? ! in0_p : in0_p,
3249 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3250 or_op ? ! in1_p : in1_p,
3252 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3253 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3254 TREE_TYPE (exp), lhs, rhs);
3261 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3262 bit value. Arrange things so the extra bits will be set to zero if and
3263 only if C is signed-extended to its full width. If MASK is nonzero,
3264 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3267 unextend (c, p, unsignedp, mask)
3273 tree type = TREE_TYPE (c);
3274 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3277 if (p == modesize || unsignedp)
3280 /* We work by getting just the sign bit into the low-order bit, then
3281 into the high-order bit, then sign-extend. We then XOR that value
3283 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3284 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3286 /* We must use a signed type in order to get an arithmetic right shift.
3287 However, we must also avoid introducing accidental overflows, so that
3288 a subsequent call to integer_zerop will work. Hence we must
3289 do the type conversion here. At this point, the constant is either
3290 zero or one, and the conversion to a signed type can never overflow.
3291 We could get an overflow if this conversion is done anywhere else. */
3292 if (TREE_UNSIGNED (type))
3293 temp = convert (signed_type (type), temp);
3295 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3296 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3298 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3299 /* If necessary, convert the type back to match the type of C. */
3300 if (TREE_UNSIGNED (type))
3301 temp = convert (type, temp);
3303 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3306 /* Find ways of folding logical expressions of LHS and RHS:
3307 Try to merge two comparisons to the same innermost item.
3308 Look for range tests like "ch >= '0' && ch <= '9'".
3309 Look for combinations of simple terms on machines with expensive branches
3310 and evaluate the RHS unconditionally.
3312 For example, if we have p->a == 2 && p->b == 4 and we can make an
3313 object large enough to span both A and B, we can do this with a comparison
3314 against the object ANDed with the a mask.
3316 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3317 operations to do this with one comparison.
3319 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3320 function and the one above.
3322 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3323 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3325 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3328 We return the simplified tree or 0 if no optimization is possible. */
3331 fold_truthop (code, truth_type, lhs, rhs)
3332 enum tree_code code;
3333 tree truth_type, lhs, rhs;
3335 /* If this is the "or" of two comparisons, we can do something if we
3336 the comparisons are NE_EXPR. If this is the "and", we can do something
3337 if the comparisons are EQ_EXPR. I.e.,
3338 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3340 WANTED_CODE is this operation code. For single bit fields, we can
3341 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3342 comparison for one-bit fields. */
3344 enum tree_code wanted_code;
3345 enum tree_code lcode, rcode;
3346 tree ll_arg, lr_arg, rl_arg, rr_arg;
3347 tree ll_inner, lr_inner, rl_inner, rr_inner;
3348 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3349 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3350 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3351 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3352 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3353 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3354 enum machine_mode lnmode, rnmode;
3355 tree ll_mask, lr_mask, rl_mask, rr_mask;
3356 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3357 tree l_const, r_const;
3359 int first_bit, end_bit;
3362 /* Start by getting the comparison codes. Fail if anything is volatile.
3363 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3364 it were surrounded with a NE_EXPR. */
3366 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3369 lcode = TREE_CODE (lhs);
3370 rcode = TREE_CODE (rhs);
3372 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3373 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3375 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3376 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3378 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3381 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3382 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3384 ll_arg = TREE_OPERAND (lhs, 0);
3385 lr_arg = TREE_OPERAND (lhs, 1);
3386 rl_arg = TREE_OPERAND (rhs, 0);
3387 rr_arg = TREE_OPERAND (rhs, 1);
3389 /* If the RHS can be evaluated unconditionally and its operands are
3390 simple, it wins to evaluate the RHS unconditionally on machines
3391 with expensive branches. In this case, this isn't a comparison
3392 that can be merged. */
3394 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3395 are with zero (tmw). */
3397 if (BRANCH_COST >= 2
3398 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3399 && simple_operand_p (rl_arg)
3400 && simple_operand_p (rr_arg))
3401 return build (code, truth_type, lhs, rhs);
3403 /* See if the comparisons can be merged. Then get all the parameters for
3406 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3407 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3411 ll_inner = decode_field_reference (ll_arg,
3412 &ll_bitsize, &ll_bitpos, &ll_mode,
3413 &ll_unsignedp, &volatilep, &ll_mask,
3415 lr_inner = decode_field_reference (lr_arg,
3416 &lr_bitsize, &lr_bitpos, &lr_mode,
3417 &lr_unsignedp, &volatilep, &lr_mask,
3419 rl_inner = decode_field_reference (rl_arg,
3420 &rl_bitsize, &rl_bitpos, &rl_mode,
3421 &rl_unsignedp, &volatilep, &rl_mask,
3423 rr_inner = decode_field_reference (rr_arg,
3424 &rr_bitsize, &rr_bitpos, &rr_mode,
3425 &rr_unsignedp, &volatilep, &rr_mask,
3428 /* It must be true that the inner operation on the lhs of each
3429 comparison must be the same if we are to be able to do anything.
3430 Then see if we have constants. If not, the same must be true for
3432 if (volatilep || ll_inner == 0 || rl_inner == 0
3433 || ! operand_equal_p (ll_inner, rl_inner, 0))
3436 if (TREE_CODE (lr_arg) == INTEGER_CST
3437 && TREE_CODE (rr_arg) == INTEGER_CST)
3438 l_const = lr_arg, r_const = rr_arg;
3439 else if (lr_inner == 0 || rr_inner == 0
3440 || ! operand_equal_p (lr_inner, rr_inner, 0))
3443 l_const = r_const = 0;
3445 /* If either comparison code is not correct for our logical operation,
3446 fail. However, we can convert a one-bit comparison against zero into
3447 the opposite comparison against that bit being set in the field. */
3449 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3450 if (lcode != wanted_code)
3452 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3454 if (ll_unsignedp || tree_log2 (ll_mask) + 1 < ll_bitsize)
3457 /* Since ll_arg is a single bit bit mask, we can sign extend
3458 it appropriately with a NEGATE_EXPR.
3459 l_const is made a signed value here, but since for l_const != NULL
3460 lr_unsignedp is not used, we don't need to clear the latter. */
3461 l_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (ll_arg),
3462 convert (TREE_TYPE (ll_arg), ll_mask)));
3468 if (rcode != wanted_code)
3470 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3472 if (rl_unsignedp || tree_log2 (rl_mask) + 1 < rl_bitsize)
3475 /* This is analogous to the code for l_const above. */
3476 r_const = fold (build1 (NEGATE_EXPR, TREE_TYPE (rl_arg),
3477 convert (TREE_TYPE (rl_arg), rl_mask)));
3483 /* See if we can find a mode that contains both fields being compared on
3484 the left. If we can't, fail. Otherwise, update all constants and masks
3485 to be relative to a field of that size. */
3486 first_bit = MIN (ll_bitpos, rl_bitpos);
3487 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3488 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3489 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3491 if (lnmode == VOIDmode)
3494 lnbitsize = GET_MODE_BITSIZE (lnmode);
3495 lnbitpos = first_bit & ~ (lnbitsize - 1);
3496 type = type_for_size (lnbitsize, 1);
3497 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3499 if (BYTES_BIG_ENDIAN)
3501 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3502 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3505 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3506 size_int (xll_bitpos), 0);
3507 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3508 size_int (xrl_bitpos), 0);
3512 l_const = convert (type, l_const);
3513 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3514 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3515 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3516 fold (build1 (BIT_NOT_EXPR,
3520 warning ("comparison is always %s",
3521 wanted_code == NE_EXPR ? "one" : "zero");
3523 return convert (truth_type,
3524 wanted_code == NE_EXPR
3525 ? integer_one_node : integer_zero_node);
3530 r_const = convert (type, r_const);
3531 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3532 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3533 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3534 fold (build1 (BIT_NOT_EXPR,
3538 warning ("comparison is always %s",
3539 wanted_code == NE_EXPR ? "one" : "zero");
3541 return convert (truth_type,
3542 wanted_code == NE_EXPR
3543 ? integer_one_node : integer_zero_node);
3547 /* If the right sides are not constant, do the same for it. Also,
3548 disallow this optimization if a size or signedness mismatch occurs
3549 between the left and right sides. */
3552 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3553 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3554 /* Make sure the two fields on the right
3555 correspond to the left without being swapped. */
3556 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3559 first_bit = MIN (lr_bitpos, rr_bitpos);
3560 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3561 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3562 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3564 if (rnmode == VOIDmode)
3567 rnbitsize = GET_MODE_BITSIZE (rnmode);
3568 rnbitpos = first_bit & ~ (rnbitsize - 1);
3569 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3571 if (BYTES_BIG_ENDIAN)
3573 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3574 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3577 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3578 size_int (xlr_bitpos), 0);
3579 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3580 size_int (xrr_bitpos), 0);
3582 /* Make a mask that corresponds to both fields being compared.
3583 Do this for both items being compared. If the masks agree,
3584 we can do this by masking both and comparing the masked
3586 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3587 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3588 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3590 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3591 ll_unsignedp || rl_unsignedp);
3592 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3593 lr_unsignedp || rr_unsignedp);
3594 if (! all_ones_mask_p (ll_mask, lnbitsize))
3596 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3597 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3599 return build (wanted_code, truth_type, lhs, rhs);
3602 /* There is still another way we can do something: If both pairs of
3603 fields being compared are adjacent, we may be able to make a wider
3604 field containing them both. */
3605 if ((ll_bitsize + ll_bitpos == rl_bitpos
3606 && lr_bitsize + lr_bitpos == rr_bitpos)
3607 || (ll_bitpos == rl_bitpos + rl_bitsize
3608 && lr_bitpos == rr_bitpos + rr_bitsize))
3609 return build (wanted_code, truth_type,
3610 make_bit_field_ref (ll_inner, type,
3611 ll_bitsize + rl_bitsize,
3612 MIN (ll_bitpos, rl_bitpos),
3614 make_bit_field_ref (lr_inner, type,
3615 lr_bitsize + rr_bitsize,
3616 MIN (lr_bitpos, rr_bitpos),
3622 /* Handle the case of comparisons with constants. If there is something in
3623 common between the masks, those bits of the constants must be the same.
3624 If not, the condition is always false. Test for this to avoid generating
3625 incorrect code below. */
3626 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3627 if (! integer_zerop (result)
3628 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3629 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3631 if (wanted_code == NE_EXPR)
3633 warning ("`or' of unmatched not-equal tests is always 1");
3634 return convert (truth_type, integer_one_node);
3638 warning ("`and' of mutually exclusive equal-tests is always zero");
3639 return convert (truth_type, integer_zero_node);
3643 /* Construct the expression we will return. First get the component
3644 reference we will make. Unless the mask is all ones the width of
3645 that field, perform the mask operation. Then compare with the
3647 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3648 ll_unsignedp || rl_unsignedp);
3650 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3651 if (! all_ones_mask_p (ll_mask, lnbitsize))
3652 result = build (BIT_AND_EXPR, type, result, ll_mask);
3654 return build (wanted_code, truth_type, result,
3655 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3658 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3659 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3660 that we may sometimes modify the tree. */
3663 strip_compound_expr (t, s)
3667 enum tree_code code = TREE_CODE (t);
3669 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3670 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3671 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3672 return TREE_OPERAND (t, 1);
3674 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3675 don't bother handling any other types. */
3676 else if (code == COND_EXPR)
3678 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3679 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3680 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3682 else if (TREE_CODE_CLASS (code) == '1')
3683 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3684 else if (TREE_CODE_CLASS (code) == '<'
3685 || TREE_CODE_CLASS (code) == '2')
3687 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3688 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3694 /* Perform constant folding and related simplification of EXPR.
3695 The related simplifications include x*1 => x, x*0 => 0, etc.,
3696 and application of the associative law.
3697 NOP_EXPR conversions may be removed freely (as long as we
3698 are careful not to change the C type of the overall expression)
3699 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3700 but we can constant-fold them if they have constant operands. */
3706 register tree t = expr;
3707 tree t1 = NULL_TREE;
3709 tree type = TREE_TYPE (expr);
3710 register tree arg0, arg1;
3711 register enum tree_code code = TREE_CODE (t);
3715 /* WINS will be nonzero when the switch is done
3716 if all operands are constant. */
3720 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3721 Likewise for a SAVE_EXPR that's already been evaluated. */
3722 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3725 /* Return right away if already constant. */
3726 if (TREE_CONSTANT (t))
3728 if (code == CONST_DECL)
3729 return DECL_INITIAL (t);
3733 kind = TREE_CODE_CLASS (code);
3734 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3738 /* Special case for conversion ops that can have fixed point args. */
3739 arg0 = TREE_OPERAND (t, 0);
3741 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3743 STRIP_TYPE_NOPS (arg0);
3745 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3746 subop = TREE_REALPART (arg0);
3750 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3751 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3752 && TREE_CODE (subop) != REAL_CST
3753 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3755 /* Note that TREE_CONSTANT isn't enough:
3756 static var addresses are constant but we can't
3757 do arithmetic on them. */
3760 else if (kind == 'e' || kind == '<'
3761 || kind == '1' || kind == '2' || kind == 'r')
3763 register int len = tree_code_length[(int) code];
3765 for (i = 0; i < len; i++)
3767 tree op = TREE_OPERAND (t, i);
3771 continue; /* Valid for CALL_EXPR, at least. */
3773 if (kind == '<' || code == RSHIFT_EXPR)
3775 /* Signedness matters here. Perhaps we can refine this
3777 STRIP_TYPE_NOPS (op);
3781 /* Strip any conversions that don't change the mode. */
3785 if (TREE_CODE (op) == COMPLEX_CST)
3786 subop = TREE_REALPART (op);
3790 if (TREE_CODE (subop) != INTEGER_CST
3791 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3792 && TREE_CODE (subop) != REAL_CST
3793 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3795 /* Note that TREE_CONSTANT isn't enough:
3796 static var addresses are constant but we can't
3797 do arithmetic on them. */
3807 /* If this is a commutative operation, and ARG0 is a constant, move it
3808 to ARG1 to reduce the number of tests below. */
3809 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3810 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3811 || code == BIT_AND_EXPR)
3812 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3814 tem = arg0; arg0 = arg1; arg1 = tem;
3816 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3817 TREE_OPERAND (t, 1) = tem;
3820 /* Now WINS is set as described above,
3821 ARG0 is the first operand of EXPR,
3822 and ARG1 is the second operand (if it has more than one operand).
3824 First check for cases where an arithmetic operation is applied to a
3825 compound, conditional, or comparison operation. Push the arithmetic
3826 operation inside the compound or conditional to see if any folding
3827 can then be done. Convert comparison to conditional for this purpose.
3828 The also optimizes non-constant cases that used to be done in
3831 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3832 one of the operands is a comparison and the other is a comparison, a
3833 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3834 code below would make the expression more complex. Change it to a
3835 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3836 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3838 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3839 || code == EQ_EXPR || code == NE_EXPR)
3840 && ((truth_value_p (TREE_CODE (arg0))
3841 && (truth_value_p (TREE_CODE (arg1))
3842 || (TREE_CODE (arg1) == BIT_AND_EXPR
3843 && integer_onep (TREE_OPERAND (arg1, 1)))))
3844 || (truth_value_p (TREE_CODE (arg1))
3845 && (truth_value_p (TREE_CODE (arg0))
3846 || (TREE_CODE (arg0) == BIT_AND_EXPR
3847 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3849 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3850 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3854 if (code == EQ_EXPR)
3855 t = invert_truthvalue (t);
3860 if (TREE_CODE_CLASS (code) == '1')
3862 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3863 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3864 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3865 else if (TREE_CODE (arg0) == COND_EXPR)
3867 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3868 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3869 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3871 /* If this was a conversion, and all we did was to move into
3872 inside the COND_EXPR, bring it back out. But leave it if
3873 it is a conversion from integer to integer and the
3874 result precision is no wider than a word since such a
3875 conversion is cheap and may be optimized away by combine,
3876 while it couldn't if it were outside the COND_EXPR. Then return
3877 so we don't get into an infinite recursion loop taking the
3878 conversion out and then back in. */
3880 if ((code == NOP_EXPR || code == CONVERT_EXPR
3881 || code == NON_LVALUE_EXPR)
3882 && TREE_CODE (t) == COND_EXPR
3883 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3884 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3885 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3886 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3887 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3888 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3889 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3890 t = build1 (code, type,
3892 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3893 TREE_OPERAND (t, 0),
3894 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3895 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3898 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3899 return fold (build (COND_EXPR, type, arg0,
3900 fold (build1 (code, type, integer_one_node)),
3901 fold (build1 (code, type, integer_zero_node))));
3903 else if (TREE_CODE_CLASS (code) == '2'
3904 || TREE_CODE_CLASS (code) == '<')
3906 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3907 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3908 fold (build (code, type,
3909 arg0, TREE_OPERAND (arg1, 1))));
3910 else if ((TREE_CODE (arg1) == COND_EXPR
3911 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3912 && TREE_CODE_CLASS (code) != '<'))
3913 && (! TREE_SIDE_EFFECTS (arg0) || current_function_decl != 0))
3915 tree test, true_value, false_value;
3917 if (TREE_CODE (arg1) == COND_EXPR)
3919 test = TREE_OPERAND (arg1, 0);
3920 true_value = TREE_OPERAND (arg1, 1);
3921 false_value = TREE_OPERAND (arg1, 2);
3925 tree testtype = TREE_TYPE (arg1);
3927 true_value = convert (testtype, integer_one_node);
3928 false_value = convert (testtype, integer_zero_node);
3931 /* If ARG0 is complex we want to make sure we only evaluate
3932 it once. Though this is only required if it is volatile, it
3933 might be more efficient even if it is not. However, if we
3934 succeed in folding one part to a constant, we do not need
3935 to make this SAVE_EXPR. Since we do this optimization
3936 primarily to see if we do end up with constant and this
3937 SAVE_EXPR interferes with later optimizations, suppressing
3938 it when we can is important. */
3940 if (TREE_CODE (arg0) != SAVE_EXPR
3941 && ((TREE_CODE (arg0) != VAR_DECL
3942 && TREE_CODE (arg0) != PARM_DECL)
3943 || TREE_SIDE_EFFECTS (arg0)))
3945 tree lhs = fold (build (code, type, arg0, true_value));
3946 tree rhs = fold (build (code, type, arg0, false_value));
3948 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3949 return fold (build (COND_EXPR, type, test, lhs, rhs));
3951 if (current_function_decl != 0)
3952 arg0 = save_expr (arg0);
3955 test = fold (build (COND_EXPR, type, test,
3956 fold (build (code, type, arg0, true_value)),
3957 fold (build (code, type, arg0, false_value))));
3958 if (TREE_CODE (arg0) == SAVE_EXPR)
3959 return build (COMPOUND_EXPR, type,
3960 convert (void_type_node, arg0),
3961 strip_compound_expr (test, arg0));
3963 return convert (type, test);
3966 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3967 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3968 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3969 else if ((TREE_CODE (arg0) == COND_EXPR
3970 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3971 && TREE_CODE_CLASS (code) != '<'))
3972 && (! TREE_SIDE_EFFECTS (arg1) || current_function_decl != 0))
3974 tree test, true_value, false_value;
3976 if (TREE_CODE (arg0) == COND_EXPR)
3978 test = TREE_OPERAND (arg0, 0);
3979 true_value = TREE_OPERAND (arg0, 1);
3980 false_value = TREE_OPERAND (arg0, 2);
3984 tree testtype = TREE_TYPE (arg0);
3986 true_value = convert (testtype, integer_one_node);
3987 false_value = convert (testtype, integer_zero_node);
3990 if (TREE_CODE (arg1) != SAVE_EXPR
3991 && ((TREE_CODE (arg1) != VAR_DECL
3992 && TREE_CODE (arg1) != PARM_DECL)
3993 || TREE_SIDE_EFFECTS (arg1)))
3995 tree lhs = fold (build (code, type, true_value, arg1));
3996 tree rhs = fold (build (code, type, false_value, arg1));
3998 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
3999 || TREE_CONSTANT (arg1))
4000 return fold (build (COND_EXPR, type, test, lhs, rhs));
4002 if (current_function_decl != 0)
4003 arg1 = save_expr (arg1);
4006 test = fold (build (COND_EXPR, type, test,
4007 fold (build (code, type, true_value, arg1)),
4008 fold (build (code, type, false_value, arg1))));
4009 if (TREE_CODE (arg1) == SAVE_EXPR)
4010 return build (COMPOUND_EXPR, type,
4011 convert (void_type_node, arg1),
4012 strip_compound_expr (test, arg1));
4014 return convert (type, test);
4017 else if (TREE_CODE_CLASS (code) == '<'
4018 && TREE_CODE (arg0) == COMPOUND_EXPR)
4019 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
4020 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
4021 else if (TREE_CODE_CLASS (code) == '<'
4022 && TREE_CODE (arg1) == COMPOUND_EXPR)
4023 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
4024 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
4036 return fold (DECL_INITIAL (t));
4041 case FIX_TRUNC_EXPR:
4042 /* Other kinds of FIX are not handled properly by fold_convert. */
4044 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
4045 return TREE_OPERAND (t, 0);
4047 /* Handle cases of two conversions in a row. */
4048 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
4049 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
4051 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4052 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
4053 tree final_type = TREE_TYPE (t);
4054 int inside_int = INTEGRAL_TYPE_P (inside_type);
4055 int inside_ptr = POINTER_TYPE_P (inside_type);
4056 int inside_float = FLOAT_TYPE_P (inside_type);
4057 int inside_prec = TYPE_PRECISION (inside_type);
4058 int inside_unsignedp = TREE_UNSIGNED (inside_type);
4059 int inter_int = INTEGRAL_TYPE_P (inter_type);
4060 int inter_ptr = POINTER_TYPE_P (inter_type);
4061 int inter_float = FLOAT_TYPE_P (inter_type);
4062 int inter_prec = TYPE_PRECISION (inter_type);
4063 int inter_unsignedp = TREE_UNSIGNED (inter_type);
4064 int final_int = INTEGRAL_TYPE_P (final_type);
4065 int final_ptr = POINTER_TYPE_P (final_type);
4066 int final_float = FLOAT_TYPE_P (final_type);
4067 int final_prec = TYPE_PRECISION (final_type);
4068 int final_unsignedp = TREE_UNSIGNED (final_type);
4070 /* In addition to the cases of two conversions in a row
4071 handled below, if we are converting something to its own
4072 type via an object of identical or wider precision, neither
4073 conversion is needed. */
4074 if (inside_type == final_type
4075 && ((inter_int && final_int) || (inter_float && final_float))
4076 && inter_prec >= final_prec)
4077 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
4079 /* Likewise, if the intermediate and final types are either both
4080 float or both integer, we don't need the middle conversion if
4081 it is wider than the final type and doesn't change the signedness
4082 (for integers). Avoid this if the final type is a pointer
4083 since then we sometimes need the inner conversion. Likewise if
4084 the outer has a precision not equal to the size of its mode. */
4085 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4086 || (inter_float && inside_float))
4087 && inter_prec >= inside_prec
4088 && (inter_float || inter_unsignedp == inside_unsignedp)
4089 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4090 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4092 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4094 /* Two conversions in a row are not needed unless:
4095 - some conversion is floating-point (overstrict for now), or
4096 - the intermediate type is narrower than both initial and
4098 - the intermediate type and innermost type differ in signedness,
4099 and the outermost type is wider than the intermediate, or
4100 - the initial type is a pointer type and the precisions of the
4101 intermediate and final types differ, or
4102 - the final type is a pointer type and the precisions of the
4103 initial and intermediate types differ. */
4104 if (! inside_float && ! inter_float && ! final_float
4105 && (inter_prec > inside_prec || inter_prec > final_prec)
4106 && ! (inside_int && inter_int
4107 && inter_unsignedp != inside_unsignedp
4108 && inter_prec < final_prec)
4109 && ((inter_unsignedp && inter_prec > inside_prec)
4110 == (final_unsignedp && final_prec > inter_prec))
4111 && ! (inside_ptr && inter_prec != final_prec)
4112 && ! (final_ptr && inside_prec != inter_prec)
4113 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4114 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4116 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4119 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4120 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4121 /* Detect assigning a bitfield. */
4122 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4123 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4125 /* Don't leave an assignment inside a conversion
4126 unless assigning a bitfield. */
4127 tree prev = TREE_OPERAND (t, 0);
4128 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4129 /* First do the assignment, then return converted constant. */
4130 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4136 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4139 return fold_convert (t, arg0);
4141 #if 0 /* This loses on &"foo"[0]. */
4146 /* Fold an expression like: "foo"[2] */
4147 if (TREE_CODE (arg0) == STRING_CST
4148 && TREE_CODE (arg1) == INTEGER_CST
4149 && !TREE_INT_CST_HIGH (arg1)
4150 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
4152 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
4153 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
4154 force_fit_type (t, 0);
4161 if (TREE_CODE (arg0) == CONSTRUCTOR)
4163 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4170 TREE_CONSTANT (t) = wins;
4176 if (TREE_CODE (arg0) == INTEGER_CST)
4178 HOST_WIDE_INT low, high;
4179 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4180 TREE_INT_CST_HIGH (arg0),
4182 t = build_int_2 (low, high);
4183 TREE_TYPE (t) = type;
4185 = (TREE_OVERFLOW (arg0)
4186 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4187 TREE_CONSTANT_OVERFLOW (t)
4188 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4190 else if (TREE_CODE (arg0) == REAL_CST)
4191 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4193 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4194 return TREE_OPERAND (arg0, 0);
4196 /* Convert - (a - b) to (b - a) for non-floating-point. */
4197 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4198 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4199 TREE_OPERAND (arg0, 0));
4206 if (TREE_CODE (arg0) == INTEGER_CST)
4208 if (! TREE_UNSIGNED (type)
4209 && TREE_INT_CST_HIGH (arg0) < 0)
4211 HOST_WIDE_INT low, high;
4212 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4213 TREE_INT_CST_HIGH (arg0),
4215 t = build_int_2 (low, high);
4216 TREE_TYPE (t) = type;
4218 = (TREE_OVERFLOW (arg0)
4219 | force_fit_type (t, overflow));
4220 TREE_CONSTANT_OVERFLOW (t)
4221 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4224 else if (TREE_CODE (arg0) == REAL_CST)
4226 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4227 t = build_real (type,
4228 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4231 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4232 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4236 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4238 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4239 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4240 TREE_OPERAND (arg0, 0),
4241 fold (build1 (NEGATE_EXPR,
4242 TREE_TYPE (TREE_TYPE (arg0)),
4243 TREE_OPERAND (arg0, 1))));
4244 else if (TREE_CODE (arg0) == COMPLEX_CST)
4245 return build_complex (type, TREE_OPERAND (arg0, 0),
4246 fold (build1 (NEGATE_EXPR,
4247 TREE_TYPE (TREE_TYPE (arg0)),
4248 TREE_OPERAND (arg0, 1))));
4249 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4250 return fold (build (TREE_CODE (arg0), type,
4251 fold (build1 (CONJ_EXPR, type,
4252 TREE_OPERAND (arg0, 0))),
4253 fold (build1 (CONJ_EXPR,
4254 type, TREE_OPERAND (arg0, 1)))));
4255 else if (TREE_CODE (arg0) == CONJ_EXPR)
4256 return TREE_OPERAND (arg0, 0);
4262 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4263 ~ TREE_INT_CST_HIGH (arg0));
4264 TREE_TYPE (t) = type;
4265 force_fit_type (t, 0);
4266 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4267 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4269 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4270 return TREE_OPERAND (arg0, 0);
4274 /* A + (-B) -> A - B */
4275 if (TREE_CODE (arg1) == NEGATE_EXPR)
4276 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4277 else if (! FLOAT_TYPE_P (type))
4279 if (integer_zerop (arg1))
4280 return non_lvalue (convert (type, arg0));
4282 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4283 with a constant, and the two constants have no bits in common,
4284 we should treat this as a BIT_IOR_EXPR since this may produce more
4286 if (TREE_CODE (arg0) == BIT_AND_EXPR
4287 && TREE_CODE (arg1) == BIT_AND_EXPR
4288 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4289 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4290 && integer_zerop (const_binop (BIT_AND_EXPR,
4291 TREE_OPERAND (arg0, 1),
4292 TREE_OPERAND (arg1, 1), 0)))
4294 code = BIT_IOR_EXPR;
4298 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4299 about the case where C is a constant, just try one of the
4300 four possibilities. */
4302 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4303 && operand_equal_p (TREE_OPERAND (arg0, 1),
4304 TREE_OPERAND (arg1, 1), 0))
4305 return fold (build (MULT_EXPR, type,
4306 fold (build (PLUS_EXPR, type,
4307 TREE_OPERAND (arg0, 0),
4308 TREE_OPERAND (arg1, 0))),
4309 TREE_OPERAND (arg0, 1)));
4311 /* In IEEE floating point, x+0 may not equal x. */
4312 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4314 && real_zerop (arg1))
4315 return non_lvalue (convert (type, arg0));
4317 /* In most languages, can't associate operations on floats
4318 through parentheses. Rather than remember where the parentheses
4319 were, we don't associate floats at all. It shouldn't matter much.
4320 However, associating multiplications is only very slightly
4321 inaccurate, so do that if -ffast-math is specified. */
4322 if (FLOAT_TYPE_P (type)
4323 && ! (flag_fast_math && code == MULT_EXPR))
4326 /* The varsign == -1 cases happen only for addition and subtraction.
4327 It says that the arg that was split was really CON minus VAR.
4328 The rest of the code applies to all associative operations. */
4334 if (split_tree (arg0, code, &var, &con, &varsign))
4338 /* EXPR is (CON-VAR) +- ARG1. */
4339 /* If it is + and VAR==ARG1, return just CONST. */
4340 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4341 return convert (TREE_TYPE (t), con);
4343 /* If ARG0 is a constant, don't change things around;
4344 instead keep all the constant computations together. */
4346 if (TREE_CONSTANT (arg0))
4349 /* Otherwise return (CON +- ARG1) - VAR. */
4350 t = build (MINUS_EXPR, type,
4351 fold (build (code, type, con, arg1)), var);
4355 /* EXPR is (VAR+CON) +- ARG1. */
4356 /* If it is - and VAR==ARG1, return just CONST. */
4357 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4358 return convert (TREE_TYPE (t), con);
4360 /* If ARG0 is a constant, don't change things around;
4361 instead keep all the constant computations together. */
4363 if (TREE_CONSTANT (arg0))
4366 /* Otherwise return VAR +- (ARG1 +- CON). */
4367 tem = fold (build (code, type, arg1, con));
4368 t = build (code, type, var, tem);
4370 if (integer_zerop (tem)
4371 && (code == PLUS_EXPR || code == MINUS_EXPR))
4372 return convert (type, var);
4373 /* If we have x +/- (c - d) [c an explicit integer]
4374 change it to x -/+ (d - c) since if d is relocatable
4375 then the latter can be a single immediate insn
4376 and the former cannot. */
4377 if (TREE_CODE (tem) == MINUS_EXPR
4378 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4380 tree tem1 = TREE_OPERAND (tem, 1);
4381 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4382 TREE_OPERAND (tem, 0) = tem1;
4384 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4390 if (split_tree (arg1, code, &var, &con, &varsign))
4392 if (TREE_CONSTANT (arg1))
4397 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4399 /* EXPR is ARG0 +- (CON +- VAR). */
4400 if (TREE_CODE (t) == MINUS_EXPR
4401 && operand_equal_p (var, arg0, 0))
4403 /* If VAR and ARG0 cancel, return just CON or -CON. */
4404 if (code == PLUS_EXPR)
4405 return convert (TREE_TYPE (t), con);
4406 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4407 convert (TREE_TYPE (t), con)));
4410 t = build (TREE_CODE (t), type,
4411 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4413 if (integer_zerop (TREE_OPERAND (t, 0))
4414 && TREE_CODE (t) == PLUS_EXPR)
4415 return convert (TREE_TYPE (t), var);
4420 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4421 if (TREE_CODE (arg1) == REAL_CST)
4423 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4425 t1 = const_binop (code, arg0, arg1, 0);
4426 if (t1 != NULL_TREE)
4428 /* The return value should always have
4429 the same type as the original expression. */
4430 if (TREE_TYPE (t1) != TREE_TYPE (t))
4431 t1 = convert (TREE_TYPE (t), t1);
4438 if (! FLOAT_TYPE_P (type))
4440 if (! wins && integer_zerop (arg0))
4441 return build1 (NEGATE_EXPR, type, arg1);
4442 if (integer_zerop (arg1))
4443 return non_lvalue (convert (type, arg0));
4445 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4446 about the case where C is a constant, just try one of the
4447 four possibilities. */
4449 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4450 && operand_equal_p (TREE_OPERAND (arg0, 1),
4451 TREE_OPERAND (arg1, 1), 0))
4452 return fold (build (MULT_EXPR, type,
4453 fold (build (MINUS_EXPR, type,
4454 TREE_OPERAND (arg0, 0),
4455 TREE_OPERAND (arg1, 0))),
4456 TREE_OPERAND (arg0, 1)));
4458 /* Convert A - (-B) to A + B. */
4459 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4460 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4462 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4465 /* Except with IEEE floating point, 0-x equals -x. */
4466 if (! wins && real_zerop (arg0))
4467 return build1 (NEGATE_EXPR, type, arg1);
4468 /* Except with IEEE floating point, x-0 equals x. */
4469 if (real_zerop (arg1))
4470 return non_lvalue (convert (type, arg0));
4473 /* Fold &x - &x. This can happen from &x.foo - &x.
4474 This is unsafe for certain floats even in non-IEEE formats.
4475 In IEEE, it is unsafe because it does wrong for NaNs.
4476 Also note that operand_equal_p is always false if an operand
4479 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4480 && operand_equal_p (arg0, arg1, 0))
4481 return convert (type, integer_zero_node);
4486 if (! FLOAT_TYPE_P (type))
4488 if (integer_zerop (arg1))
4489 return omit_one_operand (type, arg1, arg0);
4490 if (integer_onep (arg1))
4491 return non_lvalue (convert (type, arg0));
4493 /* ((A / C) * C) is A if the division is an
4494 EXACT_DIV_EXPR. Since C is normally a constant,
4495 just check for one of the four possibilities. */
4497 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4498 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4499 return TREE_OPERAND (arg0, 0);
4501 /* (a * (1 << b)) is (a << b) */
4502 if (TREE_CODE (arg1) == LSHIFT_EXPR
4503 && integer_onep (TREE_OPERAND (arg1, 0)))
4504 return fold (build (LSHIFT_EXPR, type, arg0,
4505 TREE_OPERAND (arg1, 1)));
4506 if (TREE_CODE (arg0) == LSHIFT_EXPR
4507 && integer_onep (TREE_OPERAND (arg0, 0)))
4508 return fold (build (LSHIFT_EXPR, type, arg1,
4509 TREE_OPERAND (arg0, 1)));
4513 /* x*0 is 0, except for IEEE floating point. */
4514 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4516 && real_zerop (arg1))
4517 return omit_one_operand (type, arg1, arg0);
4518 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4519 However, ANSI says we can drop signals,
4520 so we can do this anyway. */
4521 if (real_onep (arg1))
4522 return non_lvalue (convert (type, arg0));
4524 if (! wins && real_twop (arg1) && current_function_decl != 0)
4526 tree arg = save_expr (arg0);
4527 return build (PLUS_EXPR, type, arg, arg);
4535 register enum tree_code code0, code1;
4537 if (integer_all_onesp (arg1))
4538 return omit_one_operand (type, arg1, arg0);
4539 if (integer_zerop (arg1))
4540 return non_lvalue (convert (type, arg0));
4541 t1 = distribute_bit_expr (code, type, arg0, arg1);
4542 if (t1 != NULL_TREE)
4545 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4546 is a rotate of A by C1 bits. */
4547 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4548 is a rotate of A by B bits. */
4550 code0 = TREE_CODE (arg0);
4551 code1 = TREE_CODE (arg1);
4552 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4553 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4554 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4555 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4557 register tree tree01, tree11;
4558 register enum tree_code code01, code11;
4560 tree01 = TREE_OPERAND (arg0, 1);
4561 tree11 = TREE_OPERAND (arg1, 1);
4562 code01 = TREE_CODE (tree01);
4563 code11 = TREE_CODE (tree11);
4564 if (code01 == INTEGER_CST
4565 && code11 == INTEGER_CST
4566 && TREE_INT_CST_HIGH (tree01) == 0
4567 && TREE_INT_CST_HIGH (tree11) == 0
4568 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4569 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4570 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4571 code0 == LSHIFT_EXPR ? tree01 : tree11);
4572 else if (code11 == MINUS_EXPR
4573 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4574 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4575 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4576 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4577 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4578 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4579 type, TREE_OPERAND (arg0, 0), tree01);
4580 else if (code01 == MINUS_EXPR
4581 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4582 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4583 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4584 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4585 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4586 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4587 type, TREE_OPERAND (arg0, 0), tree11);
4594 if (integer_zerop (arg1))
4595 return non_lvalue (convert (type, arg0));
4596 if (integer_all_onesp (arg1))
4597 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4602 if (integer_all_onesp (arg1))
4603 return non_lvalue (convert (type, arg0));
4604 if (integer_zerop (arg1))
4605 return omit_one_operand (type, arg1, arg0);
4606 t1 = distribute_bit_expr (code, type, arg0, arg1);
4607 if (t1 != NULL_TREE)
4609 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4610 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4611 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4613 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4614 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4615 && (~TREE_INT_CST_LOW (arg0)
4616 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4617 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4619 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4620 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4622 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4623 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4624 && (~TREE_INT_CST_LOW (arg1)
4625 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4626 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4630 case BIT_ANDTC_EXPR:
4631 if (integer_all_onesp (arg0))
4632 return non_lvalue (convert (type, arg1));
4633 if (integer_zerop (arg0))
4634 return omit_one_operand (type, arg0, arg1);
4635 if (TREE_CODE (arg1) == INTEGER_CST)
4637 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4638 code = BIT_AND_EXPR;
4644 /* In most cases, do nothing with a divide by zero. */
4645 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4646 #ifndef REAL_INFINITY
4647 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4650 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4652 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4653 However, ANSI says we can drop signals, so we can do this anyway. */
4654 if (real_onep (arg1))
4655 return non_lvalue (convert (type, arg0));
4657 /* If ARG1 is a constant, we can convert this to a multiply by the
4658 reciprocal. This does not have the same rounding properties,
4659 so only do this if -ffast-math. We can actually always safely
4660 do it if ARG1 is a power of two, but it's hard to tell if it is
4661 or not in a portable manner. */
4662 if (TREE_CODE (arg1) == REAL_CST)
4665 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4667 return fold (build (MULT_EXPR, type, arg0, tem));
4668 /* Find the reciprocal if optimizing and the result is exact. */
4672 r = TREE_REAL_CST (arg1);
4673 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4675 tem = build_real (type, r);
4676 return fold (build (MULT_EXPR, type, arg0, tem));
4682 case TRUNC_DIV_EXPR:
4683 case ROUND_DIV_EXPR:
4684 case FLOOR_DIV_EXPR:
4686 case EXACT_DIV_EXPR:
4687 if (integer_onep (arg1))
4688 return non_lvalue (convert (type, arg0));
4689 if (integer_zerop (arg1))
4692 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
4693 operation, EXACT_DIV_EXPR.
4695 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
4696 At one time others generated faster code, it's not clear if they do
4697 after the last round to changes to the DIV code in expmed.c. */
4698 if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
4699 && multiple_of_p (type, arg0, arg1))
4700 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
4702 /* If we have ((a / C1) / C2) where both division are the same type, try
4703 to simplify. First see if C1 * C2 overflows or not. */
4704 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4705 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4709 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4710 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4712 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4713 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4715 /* If no overflow, divide by C1*C2. */
4716 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4720 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4721 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4722 expressions, which often appear in the offsets or sizes of
4723 objects with a varying size. Only deal with positive divisors
4724 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4726 Look for NOPs and SAVE_EXPRs inside. */
4728 if (TREE_CODE (arg1) == INTEGER_CST
4729 && tree_int_cst_sgn (arg1) >= 0)
4731 int have_save_expr = 0;
4732 tree c2 = integer_zero_node;
4735 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4736 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4740 /* Look inside the dividend and simplify using EXACT_DIV_EXPR
4742 if (TREE_CODE (xarg0) == MULT_EXPR
4743 && multiple_of_p (type, TREE_OPERAND (xarg0, 0), arg1))
4747 t = fold (build (MULT_EXPR, type,
4748 fold (build (EXACT_DIV_EXPR, type,
4749 TREE_OPERAND (xarg0, 0), arg1)),
4750 TREE_OPERAND (xarg0, 1)));
4757 if (TREE_CODE (xarg0) == MULT_EXPR
4758 && multiple_of_p (type, TREE_OPERAND (xarg0, 1), arg1))
4762 t = fold (build (MULT_EXPR, type,
4763 fold (build (EXACT_DIV_EXPR, type,
4764 TREE_OPERAND (xarg0, 1), arg1)),
4765 TREE_OPERAND (xarg0, 0)));
4771 if (TREE_CODE (xarg0) == PLUS_EXPR
4772 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4773 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4774 else if (TREE_CODE (xarg0) == MINUS_EXPR
4775 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4776 /* If we are doing this computation unsigned, the negate
4778 && ! TREE_UNSIGNED (type))
4780 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4781 xarg0 = TREE_OPERAND (xarg0, 0);
4784 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4785 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4789 if (TREE_CODE (xarg0) == MULT_EXPR
4790 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4791 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4792 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4793 TREE_OPERAND (xarg0, 1), arg1, 1))
4794 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4795 TREE_OPERAND (xarg0, 1), 1)))
4796 && (tree_int_cst_sgn (c2) >= 0
4797 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4800 tree outer_div = integer_one_node;
4801 tree c1 = TREE_OPERAND (xarg0, 1);
4804 /* If C3 > C1, set them equal and do a divide by
4805 C3/C1 at the end of the operation. */
4806 if (tree_int_cst_lt (c1, c3))
4807 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4809 /* The result is A * (C1/C3) + (C2/C3). */
4810 t = fold (build (PLUS_EXPR, type,
4811 fold (build (MULT_EXPR, type,
4812 TREE_OPERAND (xarg0, 0),
4813 const_binop (code, c1, c3, 1))),
4814 const_binop (code, c2, c3, 1)));
4816 if (! integer_onep (outer_div))
4817 t = fold (build (code, type, t, convert (type, outer_div)));
4829 case FLOOR_MOD_EXPR:
4830 case ROUND_MOD_EXPR:
4831 case TRUNC_MOD_EXPR:
4832 if (integer_onep (arg1))
4833 return omit_one_operand (type, integer_zero_node, arg0);
4834 if (integer_zerop (arg1))
4837 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4838 where C1 % C3 == 0. Handle similarly to the division case,
4839 but don't bother with SAVE_EXPRs. */
4841 if (TREE_CODE (arg1) == INTEGER_CST
4842 && ! integer_zerop (arg1))
4844 tree c2 = integer_zero_node;
4847 if (TREE_CODE (xarg0) == PLUS_EXPR
4848 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4849 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4850 else if (TREE_CODE (xarg0) == MINUS_EXPR
4851 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4852 && ! TREE_UNSIGNED (type))
4854 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4855 xarg0 = TREE_OPERAND (xarg0, 0);
4860 if (TREE_CODE (xarg0) == MULT_EXPR
4861 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4862 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4863 TREE_OPERAND (xarg0, 1),
4865 && tree_int_cst_sgn (c2) >= 0)
4866 /* The result is (C2%C3). */
4867 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4868 TREE_OPERAND (xarg0, 0));
4877 if (integer_zerop (arg1))
4878 return non_lvalue (convert (type, arg0));
4879 /* Since negative shift count is not well-defined,
4880 don't try to compute it in the compiler. */
4881 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4883 /* Rewrite an LROTATE_EXPR by a constant into an
4884 RROTATE_EXPR by a new constant. */
4885 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4887 TREE_SET_CODE (t, RROTATE_EXPR);
4888 code = RROTATE_EXPR;
4889 TREE_OPERAND (t, 1) = arg1
4892 convert (TREE_TYPE (arg1),
4893 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4895 if (tree_int_cst_sgn (arg1) < 0)
4899 /* If we have a rotate of a bit operation with the rotate count and
4900 the second operand of the bit operation both constant,
4901 permute the two operations. */
4902 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4903 && (TREE_CODE (arg0) == BIT_AND_EXPR
4904 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4905 || TREE_CODE (arg0) == BIT_IOR_EXPR
4906 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4907 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4908 return fold (build (TREE_CODE (arg0), type,
4909 fold (build (code, type,
4910 TREE_OPERAND (arg0, 0), arg1)),
4911 fold (build (code, type,
4912 TREE_OPERAND (arg0, 1), arg1))));
4914 /* Two consecutive rotates adding up to the width of the mode can
4916 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4917 && TREE_CODE (arg0) == RROTATE_EXPR
4918 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4919 && TREE_INT_CST_HIGH (arg1) == 0
4920 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4921 && ((TREE_INT_CST_LOW (arg1)
4922 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4923 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4924 return TREE_OPERAND (arg0, 0);
4929 if (operand_equal_p (arg0, arg1, 0))
4931 if (INTEGRAL_TYPE_P (type)
4932 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4933 return omit_one_operand (type, arg1, arg0);
4937 if (operand_equal_p (arg0, arg1, 0))
4939 if (INTEGRAL_TYPE_P (type)
4940 && TYPE_MAX_VALUE (type)
4941 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4942 return omit_one_operand (type, arg1, arg0);
4945 case TRUTH_NOT_EXPR:
4946 /* Note that the operand of this must be an int
4947 and its values must be 0 or 1.
4948 ("true" is a fixed value perhaps depending on the language,
4949 but we don't handle values other than 1 correctly yet.) */
4950 tem = invert_truthvalue (arg0);
4951 /* Avoid infinite recursion. */
4952 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4954 return convert (type, tem);
4956 case TRUTH_ANDIF_EXPR:
4957 /* Note that the operands of this must be ints
4958 and their values must be 0 or 1.
4959 ("true" is a fixed value perhaps depending on the language.) */
4960 /* If first arg is constant zero, return it. */
4961 if (integer_zerop (arg0))
4963 case TRUTH_AND_EXPR:
4964 /* If either arg is constant true, drop it. */
4965 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4966 return non_lvalue (arg1);
4967 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4968 return non_lvalue (arg0);
4969 /* If second arg is constant zero, result is zero, but first arg
4970 must be evaluated. */
4971 if (integer_zerop (arg1))
4972 return omit_one_operand (type, arg1, arg0);
4973 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4974 case will be handled here. */
4975 if (integer_zerop (arg0))
4976 return omit_one_operand (type, arg0, arg1);
4979 /* We only do these simplifications if we are optimizing. */
4983 /* Check for things like (A || B) && (A || C). We can convert this
4984 to A || (B && C). Note that either operator can be any of the four
4985 truth and/or operations and the transformation will still be
4986 valid. Also note that we only care about order for the
4987 ANDIF and ORIF operators. If B contains side effects, this
4988 might change the truth-value of A. */
4989 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4990 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4991 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4992 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4993 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
4994 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
4996 tree a00 = TREE_OPERAND (arg0, 0);
4997 tree a01 = TREE_OPERAND (arg0, 1);
4998 tree a10 = TREE_OPERAND (arg1, 0);
4999 tree a11 = TREE_OPERAND (arg1, 1);
5000 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
5001 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
5002 && (code == TRUTH_AND_EXPR
5003 || code == TRUTH_OR_EXPR));
5005 if (operand_equal_p (a00, a10, 0))
5006 return fold (build (TREE_CODE (arg0), type, a00,
5007 fold (build (code, type, a01, a11))));
5008 else if (commutative && operand_equal_p (a00, a11, 0))
5009 return fold (build (TREE_CODE (arg0), type, a00,
5010 fold (build (code, type, a01, a10))));
5011 else if (commutative && operand_equal_p (a01, a10, 0))
5012 return fold (build (TREE_CODE (arg0), type, a01,
5013 fold (build (code, type, a00, a11))));
5015 /* This case if tricky because we must either have commutative
5016 operators or else A10 must not have side-effects. */
5018 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
5019 && operand_equal_p (a01, a11, 0))
5020 return fold (build (TREE_CODE (arg0), type,
5021 fold (build (code, type, a00, a10)),
5025 /* See if we can build a range comparison. */
5026 if (0 != (tem = fold_range_test (t)))
5029 /* Check for the possibility of merging component references. If our
5030 lhs is another similar operation, try to merge its rhs with our
5031 rhs. Then try to merge our lhs and rhs. */
5032 if (TREE_CODE (arg0) == code
5033 && 0 != (tem = fold_truthop (code, type,
5034 TREE_OPERAND (arg0, 1), arg1)))
5035 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
5037 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
5042 case TRUTH_ORIF_EXPR:
5043 /* Note that the operands of this must be ints
5044 and their values must be 0 or true.
5045 ("true" is a fixed value perhaps depending on the language.) */
5046 /* If first arg is constant true, return it. */
5047 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5050 /* If either arg is constant zero, drop it. */
5051 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
5052 return non_lvalue (arg1);
5053 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
5054 return non_lvalue (arg0);
5055 /* If second arg is constant true, result is true, but we must
5056 evaluate first arg. */
5057 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
5058 return omit_one_operand (type, arg1, arg0);
5059 /* Likewise for first arg, but note this only occurs here for
5061 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
5062 return omit_one_operand (type, arg0, arg1);
5065 case TRUTH_XOR_EXPR:
5066 /* If either arg is constant zero, drop it. */
5067 if (integer_zerop (arg0))
5068 return non_lvalue (arg1);
5069 if (integer_zerop (arg1))
5070 return non_lvalue (arg0);
5071 /* If either arg is constant true, this is a logical inversion. */
5072 if (integer_onep (arg0))
5073 return non_lvalue (invert_truthvalue (arg1));
5074 if (integer_onep (arg1))
5075 return non_lvalue (invert_truthvalue (arg0));
5084 /* If one arg is a constant integer, put it last. */
5085 if (TREE_CODE (arg0) == INTEGER_CST
5086 && TREE_CODE (arg1) != INTEGER_CST)
5088 TREE_OPERAND (t, 0) = arg1;
5089 TREE_OPERAND (t, 1) = arg0;
5090 arg0 = TREE_OPERAND (t, 0);
5091 arg1 = TREE_OPERAND (t, 1);
5092 code = swap_tree_comparison (code);
5093 TREE_SET_CODE (t, code);
5096 /* Convert foo++ == CONST into ++foo == CONST + INCR.
5097 First, see if one arg is constant; find the constant arg
5098 and the other one. */
5100 tree constop = 0, varop;
5101 int constopnum = -1;
5103 if (TREE_CONSTANT (arg1))
5104 constopnum = 1, constop = arg1, varop = arg0;
5105 if (TREE_CONSTANT (arg0))
5106 constopnum = 0, constop = arg0, varop = arg1;
5108 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
5110 /* This optimization is invalid for ordered comparisons
5111 if CONST+INCR overflows or if foo+incr might overflow.
5112 This optimization is invalid for floating point due to rounding.
5113 For pointer types we assume overflow doesn't happen. */
5114 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5115 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5116 && (code == EQ_EXPR || code == NE_EXPR)))
5119 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
5120 constop, TREE_OPERAND (varop, 1)));
5121 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
5123 /* If VAROP is a reference to a bitfield, we must mask
5124 the constant by the width of the field. */
5125 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5126 && DECL_BIT_FIELD(TREE_OPERAND
5127 (TREE_OPERAND (varop, 0), 1)))
5130 = TREE_INT_CST_LOW (DECL_SIZE
5132 (TREE_OPERAND (varop, 0), 1)));
5134 newconst = fold (build (BIT_AND_EXPR,
5135 TREE_TYPE (varop), newconst,
5136 convert (TREE_TYPE (varop),
5137 build_int_2 (size, 0))));
5141 t = build (code, type, TREE_OPERAND (t, 0),
5142 TREE_OPERAND (t, 1));
5143 TREE_OPERAND (t, constopnum) = newconst;
5147 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
5149 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5150 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5151 && (code == EQ_EXPR || code == NE_EXPR)))
5154 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
5155 constop, TREE_OPERAND (varop, 1)));
5156 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
5158 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5159 && DECL_BIT_FIELD(TREE_OPERAND
5160 (TREE_OPERAND (varop, 0), 1)))
5163 = TREE_INT_CST_LOW (DECL_SIZE
5165 (TREE_OPERAND (varop, 0), 1)));
5167 newconst = fold (build (BIT_AND_EXPR,
5168 TREE_TYPE (varop), newconst,
5169 convert (TREE_TYPE (varop),
5170 build_int_2 (size, 0))));
5174 t = build (code, type, TREE_OPERAND (t, 0),
5175 TREE_OPERAND (t, 1));
5176 TREE_OPERAND (t, constopnum) = newconst;
5182 /* Change X >= CST to X > (CST - 1) if CST is positive. */
5183 if (TREE_CODE (arg1) == INTEGER_CST
5184 && TREE_CODE (arg0) != INTEGER_CST
5185 && tree_int_cst_sgn (arg1) > 0)
5187 switch (TREE_CODE (t))
5191 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5192 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5197 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5198 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5206 /* If this is an EQ or NE comparison with zero and ARG0 is
5207 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5208 two operations, but the latter can be done in one less insn
5209 on machines that have only two-operand insns or on which a
5210 constant cannot be the first operand. */
5211 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5212 && TREE_CODE (arg0) == BIT_AND_EXPR)
5214 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5215 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5217 fold (build (code, type,
5218 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5220 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5221 TREE_OPERAND (arg0, 1),
5222 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5223 convert (TREE_TYPE (arg0),
5226 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5227 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5229 fold (build (code, type,
5230 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5232 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5233 TREE_OPERAND (arg0, 0),
5234 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5235 convert (TREE_TYPE (arg0),
5240 /* If this is an NE or EQ comparison of zero against the result of a
5241 signed MOD operation whose second operand is a power of 2, make
5242 the MOD operation unsigned since it is simpler and equivalent. */
5243 if ((code == NE_EXPR || code == EQ_EXPR)
5244 && integer_zerop (arg1)
5245 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5246 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5247 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5248 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5249 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5250 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5252 tree newtype = unsigned_type (TREE_TYPE (arg0));
5253 tree newmod = build (TREE_CODE (arg0), newtype,
5254 convert (newtype, TREE_OPERAND (arg0, 0)),
5255 convert (newtype, TREE_OPERAND (arg0, 1)));
5257 return build (code, type, newmod, convert (newtype, arg1));
5260 /* If this is an NE comparison of zero with an AND of one, remove the
5261 comparison since the AND will give the correct value. */
5262 if (code == NE_EXPR && integer_zerop (arg1)
5263 && TREE_CODE (arg0) == BIT_AND_EXPR
5264 && integer_onep (TREE_OPERAND (arg0, 1)))
5265 return convert (type, arg0);
5267 /* If we have (A & C) == C where C is a power of 2, convert this into
5268 (A & C) != 0. Similarly for NE_EXPR. */
5269 if ((code == EQ_EXPR || code == NE_EXPR)
5270 && TREE_CODE (arg0) == BIT_AND_EXPR
5271 && integer_pow2p (TREE_OPERAND (arg0, 1))
5272 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5273 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5274 arg0, integer_zero_node);
5276 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5277 and similarly for >= into !=. */
5278 if ((code == LT_EXPR || code == GE_EXPR)
5279 && TREE_UNSIGNED (TREE_TYPE (arg0))
5280 && TREE_CODE (arg1) == LSHIFT_EXPR
5281 && integer_onep (TREE_OPERAND (arg1, 0)))
5282 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5283 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5284 TREE_OPERAND (arg1, 1)),
5285 convert (TREE_TYPE (arg0), integer_zero_node));
5287 else if ((code == LT_EXPR || code == GE_EXPR)
5288 && TREE_UNSIGNED (TREE_TYPE (arg0))
5289 && (TREE_CODE (arg1) == NOP_EXPR
5290 || TREE_CODE (arg1) == CONVERT_EXPR)
5291 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5292 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5294 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5295 convert (TREE_TYPE (arg0),
5296 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5297 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5298 convert (TREE_TYPE (arg0), integer_zero_node));
5300 /* Simplify comparison of something with itself. (For IEEE
5301 floating-point, we can only do some of these simplifications.) */
5302 if (operand_equal_p (arg0, arg1, 0))
5309 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5311 if (type == integer_type_node)
5312 return integer_one_node;
5314 t = build_int_2 (1, 0);
5315 TREE_TYPE (t) = type;
5319 TREE_SET_CODE (t, code);
5323 /* For NE, we can only do this simplification if integer. */
5324 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5326 /* ... fall through ... */
5329 if (type == integer_type_node)
5330 return integer_zero_node;
5332 t = build_int_2 (0, 0);
5333 TREE_TYPE (t) = type;
5340 /* An unsigned comparison against 0 can be simplified. */
5341 if (integer_zerop (arg1)
5342 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5343 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5344 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5346 switch (TREE_CODE (t))
5350 TREE_SET_CODE (t, NE_EXPR);
5354 TREE_SET_CODE (t, EQ_EXPR);
5357 return omit_one_operand (type,
5358 convert (type, integer_one_node),
5361 return omit_one_operand (type,
5362 convert (type, integer_zero_node),
5369 /* An unsigned <= 0x7fffffff can be simplified. */
5371 int width = TYPE_PRECISION (TREE_TYPE (arg1));
5372 if (TREE_CODE (arg1) == INTEGER_CST
5373 && ! TREE_CONSTANT_OVERFLOW (arg1)
5374 && width <= HOST_BITS_PER_WIDE_INT
5375 && TREE_INT_CST_LOW (arg1) == ((HOST_WIDE_INT) 1 << (width - 1)) - 1
5376 && TREE_INT_CST_HIGH (arg1) == 0
5377 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5378 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5379 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5381 switch (TREE_CODE (t))
5384 return fold (build (GE_EXPR, type,
5385 convert (signed_type (TREE_TYPE (arg0)),
5387 convert (signed_type (TREE_TYPE (arg1)),
5388 integer_zero_node)));
5390 return fold (build (LT_EXPR, type,
5391 convert (signed_type (TREE_TYPE (arg0)),
5393 convert (signed_type (TREE_TYPE (arg1)),
5394 integer_zero_node)));
5401 /* If we are comparing an expression that just has comparisons
5402 of two integer values, arithmetic expressions of those comparisons,
5403 and constants, we can simplify it. There are only three cases
5404 to check: the two values can either be equal, the first can be
5405 greater, or the second can be greater. Fold the expression for
5406 those three values. Since each value must be 0 or 1, we have
5407 eight possibilities, each of which corresponds to the constant 0
5408 or 1 or one of the six possible comparisons.
5410 This handles common cases like (a > b) == 0 but also handles
5411 expressions like ((x > y) - (y > x)) > 0, which supposedly
5412 occur in macroized code. */
5414 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5416 tree cval1 = 0, cval2 = 0;
5419 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5420 /* Don't handle degenerate cases here; they should already
5421 have been handled anyway. */
5422 && cval1 != 0 && cval2 != 0
5423 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5424 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5425 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5426 && TYPE_MAX_VALUE (TREE_TYPE (cval1))
5427 && TYPE_MAX_VALUE (TREE_TYPE (cval2))
5428 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5429 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5431 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5432 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5434 /* We can't just pass T to eval_subst in case cval1 or cval2
5435 was the same as ARG1. */
5438 = fold (build (code, type,
5439 eval_subst (arg0, cval1, maxval, cval2, minval),
5442 = fold (build (code, type,
5443 eval_subst (arg0, cval1, maxval, cval2, maxval),
5446 = fold (build (code, type,
5447 eval_subst (arg0, cval1, minval, cval2, maxval),
5450 /* All three of these results should be 0 or 1. Confirm they
5451 are. Then use those values to select the proper code
5454 if ((integer_zerop (high_result)
5455 || integer_onep (high_result))
5456 && (integer_zerop (equal_result)
5457 || integer_onep (equal_result))
5458 && (integer_zerop (low_result)
5459 || integer_onep (low_result)))
5461 /* Make a 3-bit mask with the high-order bit being the
5462 value for `>', the next for '=', and the low for '<'. */
5463 switch ((integer_onep (high_result) * 4)
5464 + (integer_onep (equal_result) * 2)
5465 + integer_onep (low_result))
5469 return omit_one_operand (type, integer_zero_node, arg0);
5490 return omit_one_operand (type, integer_one_node, arg0);
5493 t = build (code, type, cval1, cval2);
5495 return save_expr (t);
5502 /* If this is a comparison of a field, we may be able to simplify it. */
5503 if ((TREE_CODE (arg0) == COMPONENT_REF
5504 || TREE_CODE (arg0) == BIT_FIELD_REF)
5505 && (code == EQ_EXPR || code == NE_EXPR)
5506 /* Handle the constant case even without -O
5507 to make sure the warnings are given. */
5508 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5510 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5514 /* If this is a comparison of complex values and either or both
5515 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5516 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5517 may prevent needless evaluations. */
5518 if ((code == EQ_EXPR || code == NE_EXPR)
5519 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5520 && (TREE_CODE (arg0) == COMPLEX_EXPR
5521 || TREE_CODE (arg1) == COMPLEX_EXPR))
5523 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5524 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5525 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5526 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5527 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5529 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5532 fold (build (code, type, real0, real1)),
5533 fold (build (code, type, imag0, imag1))));
5536 /* From here on, the only cases we handle are when the result is
5537 known to be a constant.
5539 To compute GT, swap the arguments and do LT.
5540 To compute GE, do LT and invert the result.
5541 To compute LE, swap the arguments, do LT and invert the result.
5542 To compute NE, do EQ and invert the result.
5544 Therefore, the code below must handle only EQ and LT. */
5546 if (code == LE_EXPR || code == GT_EXPR)
5548 tem = arg0, arg0 = arg1, arg1 = tem;
5549 code = swap_tree_comparison (code);
5552 /* Note that it is safe to invert for real values here because we
5553 will check below in the one case that it matters. */
5556 if (code == NE_EXPR || code == GE_EXPR)
5559 code = invert_tree_comparison (code);
5562 /* Compute a result for LT or EQ if args permit;
5563 otherwise return T. */
5564 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5566 if (code == EQ_EXPR)
5567 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5568 == TREE_INT_CST_LOW (arg1))
5569 && (TREE_INT_CST_HIGH (arg0)
5570 == TREE_INT_CST_HIGH (arg1)),
5573 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5574 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5575 : INT_CST_LT (arg0, arg1)),
5579 #if 0 /* This is no longer useful, but breaks some real code. */
5580 /* Assume a nonexplicit constant cannot equal an explicit one,
5581 since such code would be undefined anyway.
5582 Exception: on sysvr4, using #pragma weak,
5583 a label can come out as 0. */
5584 else if (TREE_CODE (arg1) == INTEGER_CST
5585 && !integer_zerop (arg1)
5586 && TREE_CONSTANT (arg0)
5587 && TREE_CODE (arg0) == ADDR_EXPR
5589 t1 = build_int_2 (0, 0);
5591 /* Two real constants can be compared explicitly. */
5592 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5594 /* If either operand is a NaN, the result is false with two
5595 exceptions: First, an NE_EXPR is true on NaNs, but that case
5596 is already handled correctly since we will be inverting the
5597 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5598 or a GE_EXPR into a LT_EXPR, we must return true so that it
5599 will be inverted into false. */
5601 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5602 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5603 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5605 else if (code == EQ_EXPR)
5606 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5607 TREE_REAL_CST (arg1)),
5610 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5611 TREE_REAL_CST (arg1)),
5615 if (t1 == NULL_TREE)
5619 TREE_INT_CST_LOW (t1) ^= 1;
5621 TREE_TYPE (t1) = type;
5625 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5626 so all simple results must be passed through pedantic_non_lvalue. */
5627 if (TREE_CODE (arg0) == INTEGER_CST)
5628 return pedantic_non_lvalue
5629 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5630 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5631 return pedantic_omit_one_operand (type, arg1, arg0);
5633 /* If the second operand is zero, invert the comparison and swap
5634 the second and third operands. Likewise if the second operand
5635 is constant and the third is not or if the third operand is
5636 equivalent to the first operand of the comparison. */
5638 if (integer_zerop (arg1)
5639 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5640 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5641 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5642 TREE_OPERAND (t, 2),
5643 TREE_OPERAND (arg0, 1))))
5645 /* See if this can be inverted. If it can't, possibly because
5646 it was a floating-point inequality comparison, don't do
5648 tem = invert_truthvalue (arg0);
5650 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5652 t = build (code, type, tem,
5653 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5655 arg1 = TREE_OPERAND (t, 2);
5660 /* If we have A op B ? A : C, we may be able to convert this to a
5661 simpler expression, depending on the operation and the values
5662 of B and C. IEEE floating point prevents this though,
5663 because A or B might be -0.0 or a NaN. */
5665 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5666 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5667 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5669 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5670 arg1, TREE_OPERAND (arg0, 1)))
5672 tree arg2 = TREE_OPERAND (t, 2);
5673 enum tree_code comp_code = TREE_CODE (arg0);
5677 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5678 depending on the comparison operation. */
5679 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5680 ? real_zerop (TREE_OPERAND (arg0, 1))
5681 : integer_zerop (TREE_OPERAND (arg0, 1)))
5682 && TREE_CODE (arg2) == NEGATE_EXPR
5683 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5687 return pedantic_non_lvalue
5688 (fold (build1 (NEGATE_EXPR, type, arg1)));
5690 return pedantic_non_lvalue (convert (type, arg1));
5693 return pedantic_non_lvalue
5694 (convert (type, fold (build1 (ABS_EXPR,
5695 TREE_TYPE (arg1), arg1))));
5698 return pedantic_non_lvalue
5699 (fold (build1 (NEGATE_EXPR, type,
5701 fold (build1 (ABS_EXPR,
5708 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5711 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5713 if (comp_code == NE_EXPR)
5714 return pedantic_non_lvalue (convert (type, arg1));
5715 else if (comp_code == EQ_EXPR)
5716 return pedantic_non_lvalue (convert (type, integer_zero_node));
5719 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5720 or max (A, B), depending on the operation. */
5722 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5723 arg2, TREE_OPERAND (arg0, 0)))
5725 tree comp_op0 = TREE_OPERAND (arg0, 0);
5726 tree comp_op1 = TREE_OPERAND (arg0, 1);
5727 tree comp_type = TREE_TYPE (comp_op0);
5732 return pedantic_non_lvalue (convert (type, arg2));
5734 return pedantic_non_lvalue (convert (type, arg1));
5737 /* In C++ a ?: expression can be an lvalue, so put the
5738 operand which will be used if they are equal first
5739 so that we can convert this back to the
5740 corresponding COND_EXPR. */
5741 return pedantic_non_lvalue
5742 (convert (type, (fold (build (MIN_EXPR, comp_type,
5743 (comp_code == LE_EXPR
5744 ? comp_op0 : comp_op1),
5745 (comp_code == LE_EXPR
5746 ? comp_op1 : comp_op0))))));
5750 return pedantic_non_lvalue
5751 (convert (type, fold (build (MAX_EXPR, comp_type,
5752 (comp_code == GE_EXPR
5753 ? comp_op0 : comp_op1),
5754 (comp_code == GE_EXPR
5755 ? comp_op1 : comp_op0)))));
5762 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5763 we might still be able to simplify this. For example,
5764 if C1 is one less or one more than C2, this might have started
5765 out as a MIN or MAX and been transformed by this function.
5766 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5768 if (INTEGRAL_TYPE_P (type)
5769 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5770 && TREE_CODE (arg2) == INTEGER_CST)
5774 /* We can replace A with C1 in this case. */
5775 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5776 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5777 TREE_OPERAND (t, 2));
5781 /* If C1 is C2 + 1, this is min(A, C2). */
5782 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5783 && operand_equal_p (TREE_OPERAND (arg0, 1),
5784 const_binop (PLUS_EXPR, arg2,
5785 integer_one_node, 0), 1))
5786 return pedantic_non_lvalue
5787 (fold (build (MIN_EXPR, type, arg1, arg2)));
5791 /* If C1 is C2 - 1, this is min(A, C2). */
5792 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5793 && operand_equal_p (TREE_OPERAND (arg0, 1),
5794 const_binop (MINUS_EXPR, arg2,
5795 integer_one_node, 0), 1))
5796 return pedantic_non_lvalue
5797 (fold (build (MIN_EXPR, type, arg1, arg2)));
5801 /* If C1 is C2 - 1, this is max(A, C2). */
5802 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5803 && operand_equal_p (TREE_OPERAND (arg0, 1),
5804 const_binop (MINUS_EXPR, arg2,
5805 integer_one_node, 0), 1))
5806 return pedantic_non_lvalue
5807 (fold (build (MAX_EXPR, type, arg1, arg2)));
5811 /* If C1 is C2 + 1, this is max(A, C2). */
5812 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5813 && operand_equal_p (TREE_OPERAND (arg0, 1),
5814 const_binop (PLUS_EXPR, arg2,
5815 integer_one_node, 0), 1))
5816 return pedantic_non_lvalue
5817 (fold (build (MAX_EXPR, type, arg1, arg2)));
5826 /* If the second operand is simpler than the third, swap them
5827 since that produces better jump optimization results. */
5828 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5829 || TREE_CODE (arg1) == SAVE_EXPR)
5830 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5831 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5832 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5834 /* See if this can be inverted. If it can't, possibly because
5835 it was a floating-point inequality comparison, don't do
5837 tem = invert_truthvalue (arg0);
5839 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5841 t = build (code, type, tem,
5842 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5844 arg1 = TREE_OPERAND (t, 2);
5849 /* Convert A ? 1 : 0 to simply A. */
5850 if (integer_onep (TREE_OPERAND (t, 1))
5851 && integer_zerop (TREE_OPERAND (t, 2))
5852 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5853 call to fold will try to move the conversion inside
5854 a COND, which will recurse. In that case, the COND_EXPR
5855 is probably the best choice, so leave it alone. */
5856 && type == TREE_TYPE (arg0))
5857 return pedantic_non_lvalue (arg0);
5859 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5860 operation is simply A & 2. */
5862 if (integer_zerop (TREE_OPERAND (t, 2))
5863 && TREE_CODE (arg0) == NE_EXPR
5864 && integer_zerop (TREE_OPERAND (arg0, 1))
5865 && integer_pow2p (arg1)
5866 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5867 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5869 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5874 /* When pedantic, a compound expression can be neither an lvalue
5875 nor an integer constant expression. */
5876 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5878 /* Don't let (0, 0) be null pointer constant. */
5879 if (integer_zerop (arg1))
5880 return non_lvalue (arg1);
5885 return build_complex (type, arg0, arg1);
5889 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5891 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5892 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5893 TREE_OPERAND (arg0, 1));
5894 else if (TREE_CODE (arg0) == COMPLEX_CST)
5895 return TREE_REALPART (arg0);
5896 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5897 return fold (build (TREE_CODE (arg0), type,
5898 fold (build1 (REALPART_EXPR, type,
5899 TREE_OPERAND (arg0, 0))),
5900 fold (build1 (REALPART_EXPR,
5901 type, TREE_OPERAND (arg0, 1)))));
5905 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5906 return convert (type, integer_zero_node);
5907 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5908 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5909 TREE_OPERAND (arg0, 0));
5910 else if (TREE_CODE (arg0) == COMPLEX_CST)
5911 return TREE_IMAGPART (arg0);
5912 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5913 return fold (build (TREE_CODE (arg0), type,
5914 fold (build1 (IMAGPART_EXPR, type,
5915 TREE_OPERAND (arg0, 0))),
5916 fold (build1 (IMAGPART_EXPR, type,
5917 TREE_OPERAND (arg0, 1)))));
5920 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5922 case CLEANUP_POINT_EXPR:
5923 if (! TREE_SIDE_EFFECTS (arg0))
5924 return TREE_OPERAND (t, 0);
5927 enum tree_code code0 = TREE_CODE (arg0);
5928 int kind0 = TREE_CODE_CLASS (code0);
5929 tree arg00 = TREE_OPERAND (arg0, 0);
5932 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5933 return fold (build1 (code0, type,
5934 fold (build1 (CLEANUP_POINT_EXPR,
5935 TREE_TYPE (arg00), arg00))));
5937 if (kind0 == '<' || kind0 == '2'
5938 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5939 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5940 || code0 == TRUTH_XOR_EXPR)
5942 arg01 = TREE_OPERAND (arg0, 1);
5944 if (! TREE_SIDE_EFFECTS (arg00))
5945 return fold (build (code0, type, arg00,
5946 fold (build1 (CLEANUP_POINT_EXPR,
5947 TREE_TYPE (arg01), arg01))));
5949 if (! TREE_SIDE_EFFECTS (arg01))
5950 return fold (build (code0, type,
5951 fold (build1 (CLEANUP_POINT_EXPR,
5952 TREE_TYPE (arg00), arg00)),
5961 } /* switch (code) */
5964 /* Determine if first argument is a multiple of second argument.
5965 Return 0 if it is not, or is not easily determined to so be.
5967 An example of the sort of thing we care about (at this point --
5968 this routine could surely be made more general, and expanded
5969 to do what the *_DIV_EXPR's fold() cases do now) is discovering
5972 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5978 when we know that the two `SAVE_EXPR (J * 8)' nodes are the
5979 same node (which means they will have the same value at run
5980 time, even though we don't know when they'll be assigned).
5982 This code also handles discovering that
5984 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5990 (of course) so we don't have to worry about dealing with a
5993 Note that we _look_ inside a SAVE_EXPR only to determine
5994 how it was calculated; it is not safe for fold() to do much
5995 of anything else with the internals of a SAVE_EXPR, since
5996 fold() cannot know when it will be evaluated at run time.
5997 For example, the latter example above _cannot_ be implemented
6002 or any variant thereof, since the value of J at evaluation time
6003 of the original SAVE_EXPR is not necessarily the same at the time
6004 the new expression is evaluated. The only optimization of this
6005 sort that would be valid is changing
6007 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
6013 SAVE_EXPR (I) * SAVE_EXPR (J)
6015 (where the same SAVE_EXPR (J) is used in the original and the
6016 transformed version). */
6019 multiple_of_p (type, top, bottom)
6024 if (operand_equal_p (top, bottom, 0))
6027 if (TREE_CODE (type) != INTEGER_TYPE)
6030 switch (TREE_CODE (top))
6033 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6034 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6038 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
6039 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
6042 /* Punt if conversion from non-integral or wider integral type. */
6043 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
6044 || (TYPE_PRECISION (type)
6045 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
6049 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
6052 if ((TREE_CODE (bottom) != INTEGER_CST)
6053 || (tree_int_cst_sgn (top) < 0)
6054 || (tree_int_cst_sgn (bottom) < 0))
6056 return integer_zerop (const_binop (TRUNC_MOD_EXPR,