1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92, 93, 94, 95, 1996 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 and size_binop.
32 fold takes a tree as argument and returns a simplified tree.
34 size_binop takes a tree code for an arithmetic operation
35 and two operands that are trees, and produces a tree for the
36 result, assuming the type comes from `sizetype'.
38 size_int takes an integer value, and creates a tree constant
39 with type from `sizetype'. */
47 /* Handle floating overflow for `const_binop'. */
48 static jmp_buf float_error;
50 static void encode PROTO((HOST_WIDE_INT *,
51 HOST_WIDE_INT, HOST_WIDE_INT));
52 static void decode PROTO((HOST_WIDE_INT *,
53 HOST_WIDE_INT *, HOST_WIDE_INT *));
54 int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
55 HOST_WIDE_INT, HOST_WIDE_INT,
56 HOST_WIDE_INT, HOST_WIDE_INT *,
57 HOST_WIDE_INT *, HOST_WIDE_INT *,
59 static int split_tree PROTO((tree, enum tree_code, tree *,
61 static tree const_binop PROTO((enum tree_code, tree, tree, int));
62 static tree fold_convert PROTO((tree, tree));
63 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
64 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
65 static int truth_value_p PROTO((enum tree_code));
66 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
67 static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
68 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
69 static tree omit_one_operand PROTO((tree, tree, tree));
70 static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
71 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
72 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
73 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
75 static tree decode_field_reference PROTO((tree, int *, int *,
76 enum machine_mode *, int *,
77 int *, tree *, tree *));
78 static int all_ones_mask_p PROTO((tree, int));
79 static int simple_operand_p PROTO((tree));
80 static tree range_binop PROTO((enum tree_code, tree, tree, int,
82 static tree make_range PROTO((tree, int *, tree *, tree *));
83 static tree build_range_check PROTO((tree, tree, int, tree, tree));
84 static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
86 static tree fold_range_test PROTO((tree));
87 static tree unextend PROTO((tree, int, int, tree));
88 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
89 static tree strip_compound_expr PROTO((tree, tree));
95 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
96 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
97 Then this yields nonzero if overflow occurred during the addition.
98 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
99 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
100 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
102 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
103 We do that by representing the two-word integer in 4 words, with only
104 HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
107 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
108 #define HIGHPART(x) \
109 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
110 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
112 /* Unpack a two-word integer into 4 words.
113 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
114 WORDS points to the array of HOST_WIDE_INTs. */
117 encode (words, low, hi)
118 HOST_WIDE_INT *words;
119 HOST_WIDE_INT low, hi;
121 words[0] = LOWPART (low);
122 words[1] = HIGHPART (low);
123 words[2] = LOWPART (hi);
124 words[3] = HIGHPART (hi);
127 /* Pack an array of 4 words into a two-word integer.
128 WORDS points to the array of words.
129 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
132 decode (words, low, hi)
133 HOST_WIDE_INT *words;
134 HOST_WIDE_INT *low, *hi;
136 *low = words[0] | words[1] * BASE;
137 *hi = words[2] | words[3] * BASE;
140 /* Make the integer constant T valid for its type
141 by setting to 0 or 1 all the bits in the constant
142 that don't belong in the type.
143 Yield 1 if a signed overflow occurs, 0 otherwise.
144 If OVERFLOW is nonzero, a signed overflow has already occurred
145 in calculating T, so propagate it.
147 Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
151 force_fit_type (t, overflow)
155 HOST_WIDE_INT low, high;
158 if (TREE_CODE (t) == REAL_CST)
160 #ifdef CHECK_FLOAT_VALUE
161 CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
167 else if (TREE_CODE (t) != INTEGER_CST)
170 low = TREE_INT_CST_LOW (t);
171 high = TREE_INT_CST_HIGH (t);
173 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
176 prec = TYPE_PRECISION (TREE_TYPE (t));
178 /* First clear all bits that are beyond the type's precision. */
180 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
182 else if (prec > HOST_BITS_PER_WIDE_INT)
184 TREE_INT_CST_HIGH (t)
185 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
189 TREE_INT_CST_HIGH (t) = 0;
190 if (prec < HOST_BITS_PER_WIDE_INT)
191 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
194 /* Unsigned types do not suffer sign extension or overflow. */
195 if (TREE_UNSIGNED (TREE_TYPE (t)))
198 /* If the value's sign bit is set, extend the sign. */
199 if (prec != 2 * HOST_BITS_PER_WIDE_INT
200 && (prec > HOST_BITS_PER_WIDE_INT
201 ? (TREE_INT_CST_HIGH (t)
202 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
203 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
205 /* Value is negative:
206 set to 1 all the bits that are outside this type's precision. */
207 if (prec > HOST_BITS_PER_WIDE_INT)
209 TREE_INT_CST_HIGH (t)
210 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
214 TREE_INT_CST_HIGH (t) = -1;
215 if (prec < HOST_BITS_PER_WIDE_INT)
216 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
220 /* Yield nonzero if signed overflow occurred. */
222 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
226 /* Add two doubleword integers with doubleword result.
227 Each argument is given as two `HOST_WIDE_INT' pieces.
228 One argument is L1 and H1; the other, L2 and H2.
229 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
232 add_double (l1, h1, l2, h2, lv, hv)
233 HOST_WIDE_INT l1, h1, l2, h2;
234 HOST_WIDE_INT *lv, *hv;
239 h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
243 return overflow_sum_sign (h1, h2, h);
246 /* Negate a doubleword integer with doubleword result.
247 Return nonzero if the operation overflows, assuming it's signed.
248 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
249 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
252 neg_double (l1, h1, lv, hv)
253 HOST_WIDE_INT l1, h1;
254 HOST_WIDE_INT *lv, *hv;
260 return (*hv & h1) < 0;
270 /* Multiply two doubleword integers with doubleword result.
271 Return nonzero if the operation overflows, assuming it's signed.
272 Each argument is given as two `HOST_WIDE_INT' pieces.
273 One argument is L1 and H1; the other, L2 and H2.
274 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
277 mul_double (l1, h1, l2, h2, lv, hv)
278 HOST_WIDE_INT l1, h1, l2, h2;
279 HOST_WIDE_INT *lv, *hv;
281 HOST_WIDE_INT arg1[4];
282 HOST_WIDE_INT arg2[4];
283 HOST_WIDE_INT prod[4 * 2];
284 register unsigned HOST_WIDE_INT carry;
285 register int i, j, k;
286 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
288 encode (arg1, l1, h1);
289 encode (arg2, l2, h2);
291 bzero ((char *) prod, sizeof prod);
293 for (i = 0; i < 4; i++)
296 for (j = 0; j < 4; j++)
299 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
300 carry += arg1[i] * arg2[j];
301 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
303 prod[k] = LOWPART (carry);
304 carry = HIGHPART (carry);
309 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
311 /* Check for overflow by calculating the top half of the answer in full;
312 it should agree with the low half's sign bit. */
313 decode (prod+4, &toplow, &tophigh);
316 neg_double (l2, h2, &neglow, &neghigh);
317 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
321 neg_double (l1, h1, &neglow, &neghigh);
322 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
324 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
327 /* Shift the doubleword integer in L1, H1 left by COUNT places
328 keeping only PREC bits of result.
329 Shift right if COUNT is negative.
330 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
331 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
334 lshift_double (l1, h1, count, prec, lv, hv, arith)
335 HOST_WIDE_INT l1, h1, count;
337 HOST_WIDE_INT *lv, *hv;
342 rshift_double (l1, h1, - count, prec, lv, hv, arith);
346 #ifdef SHIFT_COUNT_TRUNCATED
347 if (SHIFT_COUNT_TRUNCATED)
351 if (count >= HOST_BITS_PER_WIDE_INT)
353 *hv = (unsigned HOST_WIDE_INT) l1 << count - HOST_BITS_PER_WIDE_INT;
358 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
359 | ((unsigned HOST_WIDE_INT) l1 >> HOST_BITS_PER_WIDE_INT - count - 1 >> 1));
360 *lv = (unsigned HOST_WIDE_INT) l1 << count;
364 /* Shift the doubleword integer in L1, H1 right by COUNT places
365 keeping only PREC bits of result. COUNT must be positive.
366 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
367 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
370 rshift_double (l1, h1, count, prec, lv, hv, arith)
371 HOST_WIDE_INT l1, h1, count;
373 HOST_WIDE_INT *lv, *hv;
376 unsigned HOST_WIDE_INT signmask;
378 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
381 #ifdef SHIFT_COUNT_TRUNCATED
382 if (SHIFT_COUNT_TRUNCATED)
386 if (count >= HOST_BITS_PER_WIDE_INT)
389 *lv = ((signmask << 2 * HOST_BITS_PER_WIDE_INT - count - 1 << 1)
390 | ((unsigned HOST_WIDE_INT) h1 >> count - HOST_BITS_PER_WIDE_INT));
394 *lv = (((unsigned HOST_WIDE_INT) l1 >> count)
395 | ((unsigned HOST_WIDE_INT) h1 << HOST_BITS_PER_WIDE_INT - count - 1 << 1));
396 *hv = ((signmask << HOST_BITS_PER_WIDE_INT - count)
397 | ((unsigned HOST_WIDE_INT) h1 >> count));
401 /* Rotate the doubleword integer in L1, H1 left by COUNT places
402 keeping only PREC bits of result.
403 Rotate right if COUNT is negative.
404 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
407 lrotate_double (l1, h1, count, prec, lv, hv)
408 HOST_WIDE_INT l1, h1, count;
410 HOST_WIDE_INT *lv, *hv;
412 HOST_WIDE_INT s1l, s1h, s2l, s2h;
418 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
419 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
424 /* Rotate the doubleword integer in L1, H1 left by COUNT places
425 keeping only PREC bits of result. COUNT must be positive.
426 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
429 rrotate_double (l1, h1, count, prec, lv, hv)
430 HOST_WIDE_INT l1, h1, count;
432 HOST_WIDE_INT *lv, *hv;
434 HOST_WIDE_INT s1l, s1h, s2l, s2h;
440 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
441 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
446 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
447 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
448 CODE is a tree code for a kind of division, one of
449 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
451 It controls how the quotient is rounded to a integer.
452 Return nonzero if the operation overflows.
453 UNS nonzero says do unsigned division. */
456 div_and_round_double (code, uns,
457 lnum_orig, hnum_orig, lden_orig, hden_orig,
458 lquo, hquo, lrem, hrem)
461 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
462 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
463 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
466 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
467 HOST_WIDE_INT den[4], quo[4];
469 unsigned HOST_WIDE_INT work;
470 register unsigned HOST_WIDE_INT carry = 0;
471 HOST_WIDE_INT lnum = lnum_orig;
472 HOST_WIDE_INT hnum = hnum_orig;
473 HOST_WIDE_INT lden = lden_orig;
474 HOST_WIDE_INT hden = hden_orig;
477 if ((hden == 0) && (lden == 0))
480 /* calculate quotient sign and convert operands to unsigned. */
486 /* (minimum integer) / (-1) is the only overflow case. */
487 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
493 neg_double (lden, hden, &lden, &hden);
497 if (hnum == 0 && hden == 0)
498 { /* single precision */
500 /* This unsigned division rounds toward zero. */
501 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
506 { /* trivial case: dividend < divisor */
507 /* hden != 0 already checked. */
514 bzero ((char *) quo, sizeof quo);
516 bzero ((char *) num, sizeof num); /* to zero 9th element */
517 bzero ((char *) den, sizeof den);
519 encode (num, lnum, hnum);
520 encode (den, lden, hden);
522 /* Special code for when the divisor < BASE. */
523 if (hden == 0 && lden < BASE)
525 /* hnum != 0 already checked. */
526 for (i = 4 - 1; i >= 0; i--)
528 work = num[i] + carry * BASE;
529 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
530 carry = work % (unsigned HOST_WIDE_INT) lden;
535 /* Full double precision division,
536 with thanks to Don Knuth's "Seminumerical Algorithms". */
537 int num_hi_sig, den_hi_sig;
538 unsigned HOST_WIDE_INT quo_est, scale;
540 /* Find the highest non-zero divisor digit. */
541 for (i = 4 - 1; ; i--)
547 /* Insure that the first digit of the divisor is at least BASE/2.
548 This is required by the quotient digit estimation algorithm. */
550 scale = BASE / (den[den_hi_sig] + 1);
551 if (scale > 1) { /* scale divisor and dividend */
553 for (i = 0; i <= 4 - 1; i++) {
554 work = (num[i] * scale) + carry;
555 num[i] = LOWPART (work);
556 carry = HIGHPART (work);
559 for (i = 0; i <= 4 - 1; i++) {
560 work = (den[i] * scale) + carry;
561 den[i] = LOWPART (work);
562 carry = HIGHPART (work);
563 if (den[i] != 0) den_hi_sig = i;
570 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
571 /* guess the next quotient digit, quo_est, by dividing the first
572 two remaining dividend digits by the high order quotient digit.
573 quo_est is never low and is at most 2 high. */
574 unsigned HOST_WIDE_INT tmp;
576 num_hi_sig = i + den_hi_sig + 1;
577 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
578 if (num[num_hi_sig] != den[den_hi_sig])
579 quo_est = work / den[den_hi_sig];
583 /* refine quo_est so it's usually correct, and at most one high. */
584 tmp = work - quo_est * den[den_hi_sig];
586 && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
589 /* Try QUO_EST as the quotient digit, by multiplying the
590 divisor by QUO_EST and subtracting from the remaining dividend.
591 Keep in mind that QUO_EST is the I - 1st digit. */
594 for (j = 0; j <= den_hi_sig; j++)
596 work = quo_est * den[j] + carry;
597 carry = HIGHPART (work);
598 work = num[i + j] - LOWPART (work);
599 num[i + j] = LOWPART (work);
600 carry += HIGHPART (work) != 0;
603 /* if quo_est was high by one, then num[i] went negative and
604 we need to correct things. */
606 if (num[num_hi_sig] < carry)
609 carry = 0; /* add divisor back in */
610 for (j = 0; j <= den_hi_sig; j++)
612 work = num[i + j] + den[j] + carry;
613 carry = HIGHPART (work);
614 num[i + j] = LOWPART (work);
616 num [num_hi_sig] += carry;
619 /* store the quotient digit. */
624 decode (quo, lquo, hquo);
627 /* if result is negative, make it so. */
629 neg_double (*lquo, *hquo, lquo, hquo);
631 /* compute trial remainder: rem = num - (quo * den) */
632 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
633 neg_double (*lrem, *hrem, lrem, hrem);
634 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
639 case TRUNC_MOD_EXPR: /* round toward zero */
640 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
644 case FLOOR_MOD_EXPR: /* round toward negative infinity */
645 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
648 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
651 else return overflow;
655 case CEIL_MOD_EXPR: /* round toward positive infinity */
656 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
658 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
661 else return overflow;
665 case ROUND_MOD_EXPR: /* round to closest integer */
667 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
668 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
670 /* get absolute values */
671 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
672 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
674 /* if (2 * abs (lrem) >= abs (lden)) */
675 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
676 labs_rem, habs_rem, <wice, &htwice);
677 if (((unsigned HOST_WIDE_INT) habs_den
678 < (unsigned HOST_WIDE_INT) htwice)
679 || (((unsigned HOST_WIDE_INT) habs_den
680 == (unsigned HOST_WIDE_INT) htwice)
681 && ((HOST_WIDE_INT unsigned) labs_den
682 < (unsigned HOST_WIDE_INT) ltwice)))
686 add_double (*lquo, *hquo,
687 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
690 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
693 else return overflow;
701 /* compute true remainder: rem = num - (quo * den) */
702 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
703 neg_double (*lrem, *hrem, lrem, hrem);
704 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
708 #ifndef REAL_ARITHMETIC
709 /* Effectively truncate a real value to represent the nearest possible value
710 in a narrower mode. The result is actually represented in the same data
711 type as the argument, but its value is usually different.
713 A trap may occur during the FP operations and it is the responsibility
714 of the calling function to have a handler established. */
717 real_value_truncate (mode, arg)
718 enum machine_mode mode;
721 return REAL_VALUE_TRUNCATE (mode, arg);
724 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
726 /* Check for infinity in an IEEE double precision number. */
732 /* The IEEE 64-bit double format. */
737 unsigned exponent : 11;
738 unsigned mantissa1 : 20;
743 unsigned mantissa1 : 20;
744 unsigned exponent : 11;
750 if (u.big_endian.sign == 1)
753 return (u.big_endian.exponent == 2047
754 && u.big_endian.mantissa1 == 0
755 && u.big_endian.mantissa2 == 0);
760 return (u.little_endian.exponent == 2047
761 && u.little_endian.mantissa1 == 0
762 && u.little_endian.mantissa2 == 0);
766 /* Check whether an IEEE double precision number is a NaN. */
772 /* The IEEE 64-bit double format. */
777 unsigned exponent : 11;
778 unsigned mantissa1 : 20;
783 unsigned mantissa1 : 20;
784 unsigned exponent : 11;
790 if (u.big_endian.sign == 1)
793 return (u.big_endian.exponent == 2047
794 && (u.big_endian.mantissa1 != 0
795 || u.big_endian.mantissa2 != 0));
800 return (u.little_endian.exponent == 2047
801 && (u.little_endian.mantissa1 != 0
802 || u.little_endian.mantissa2 != 0));
806 /* Check for a negative IEEE double precision number. */
812 /* The IEEE 64-bit double format. */
817 unsigned exponent : 11;
818 unsigned mantissa1 : 20;
823 unsigned mantissa1 : 20;
824 unsigned exponent : 11;
830 if (u.big_endian.sign == 1)
833 return u.big_endian.sign;
838 return u.little_endian.sign;
841 #else /* Target not IEEE */
843 /* Let's assume other float formats don't have infinity.
844 (This can be overridden by redefining REAL_VALUE_ISINF.) */
852 /* Let's assume other float formats don't have NaNs.
853 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
861 /* Let's assume other float formats don't have minus zero.
862 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
869 #endif /* Target not IEEE */
871 /* Try to change R into its exact multiplicative inverse in machine mode
872 MODE. Return nonzero function value if successful. */
875 exact_real_inverse (mode, r)
876 enum machine_mode mode;
886 /* Usually disable if bounds checks are not reliable. */
887 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
890 /* Set array index to the less significant bits in the unions, depending
891 on the endian-ness of the host doubles.
892 Disable if insufficient information on the data structure. */
893 #if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
896 #if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
899 #if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
902 #define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
907 if (setjmp (float_error))
909 /* Don't do the optimization if there was an arithmetic error. */
911 set_float_handler (NULL_PTR);
914 set_float_handler (float_error);
916 /* Domain check the argument. */
922 if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
926 /* Compute the reciprocal and check for numerical exactness.
927 It is unnecessary to check all the significand bits to determine
928 whether X is a power of 2. If X is not, then it is impossible for
929 the bottom half significand of both X and 1/X to be all zero bits.
930 Hence we ignore the data structure of the top half and examine only
931 the low order bits of the two significands. */
933 if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
936 /* Truncate to the required mode and range-check the result. */
937 y.d = REAL_VALUE_TRUNCATE (mode, t.d);
938 #ifdef CHECK_FLOAT_VALUE
940 if (CHECK_FLOAT_VALUE (mode, y.d, i))
944 /* Fail if truncation changed the value. */
945 if (y.d != t.d || y.d == 0.0)
949 if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
953 /* Output the reciprocal and return success flag. */
954 set_float_handler (NULL_PTR);
958 #endif /* no REAL_ARITHMETIC */
960 /* Split a tree IN into a constant and a variable part
961 that could be combined with CODE to make IN.
962 CODE must be a commutative arithmetic operation.
963 Store the constant part into *CONP and the variable in &VARP.
964 Return 1 if this was done; zero means the tree IN did not decompose
967 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
968 Therefore, we must tell the caller whether the variable part
969 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
970 The value stored is the coefficient for the variable term.
971 The constant term we return should always be added;
972 we negate it if necessary. */
975 split_tree (in, code, varp, conp, varsignp)
981 register tree outtype = TREE_TYPE (in);
985 /* Strip any conversions that don't change the machine mode. */
986 while ((TREE_CODE (in) == NOP_EXPR
987 || TREE_CODE (in) == CONVERT_EXPR)
988 && (TYPE_MODE (TREE_TYPE (in))
989 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
990 in = TREE_OPERAND (in, 0);
992 if (TREE_CODE (in) == code
993 || (! FLOAT_TYPE_P (TREE_TYPE (in))
994 /* We can associate addition and subtraction together
995 (even though the C standard doesn't say so)
996 for integers because the value is not affected.
997 For reals, the value might be affected, so we can't. */
998 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
999 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1001 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1002 if (code == INTEGER_CST)
1004 *conp = TREE_OPERAND (in, 0);
1005 *varp = TREE_OPERAND (in, 1);
1006 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1007 && TREE_TYPE (*varp) != outtype)
1008 *varp = convert (outtype, *varp);
1009 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1012 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1014 *conp = TREE_OPERAND (in, 1);
1015 *varp = TREE_OPERAND (in, 0);
1017 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1018 && TREE_TYPE (*varp) != outtype)
1019 *varp = convert (outtype, *varp);
1020 if (TREE_CODE (in) == MINUS_EXPR)
1022 /* If operation is subtraction and constant is second,
1023 must negate it to get an additive constant.
1024 And this cannot be done unless it is a manifest constant.
1025 It could also be the address of a static variable.
1026 We cannot negate that, so give up. */
1027 if (TREE_CODE (*conp) == INTEGER_CST)
1028 /* Subtracting from integer_zero_node loses for long long. */
1029 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1035 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1037 *conp = TREE_OPERAND (in, 0);
1038 *varp = TREE_OPERAND (in, 1);
1039 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1040 && TREE_TYPE (*varp) != outtype)
1041 *varp = convert (outtype, *varp);
1042 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1049 /* Combine two constants ARG1 and ARG2 under operation CODE
1050 to produce a new constant.
1051 We assume ARG1 and ARG2 have the same data type,
1052 or at least are the same kind of constant and the same machine mode.
1054 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1057 const_binop (code, arg1, arg2, notrunc)
1058 enum tree_code code;
1059 register tree arg1, arg2;
1062 STRIP_NOPS (arg1); STRIP_NOPS (arg2);
1064 if (TREE_CODE (arg1) == INTEGER_CST)
1066 register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1);
1067 register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1);
1068 HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2);
1069 HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2);
1070 HOST_WIDE_INT low, hi;
1071 HOST_WIDE_INT garbagel, garbageh;
1073 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1079 t = build_int_2 (int1l | int2l, int1h | int2h);
1083 t = build_int_2 (int1l ^ int2l, int1h ^ int2h);
1087 t = build_int_2 (int1l & int2l, int1h & int2h);
1090 case BIT_ANDTC_EXPR:
1091 t = build_int_2 (int1l & ~int2l, int1h & ~int2h);
1097 /* It's unclear from the C standard whether shifts can overflow.
1098 The following code ignores overflow; perhaps a C standard
1099 interpretation ruling is needed. */
1100 lshift_double (int1l, int1h, int2l,
1101 TYPE_PRECISION (TREE_TYPE (arg1)),
1104 t = build_int_2 (low, hi);
1105 TREE_TYPE (t) = TREE_TYPE (arg1);
1107 force_fit_type (t, 0);
1108 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2);
1109 TREE_CONSTANT_OVERFLOW (t)
1110 = TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2);
1116 lrotate_double (int1l, int1h, int2l,
1117 TYPE_PRECISION (TREE_TYPE (arg1)),
1119 t = build_int_2 (low, hi);
1126 if ((unsigned HOST_WIDE_INT) int2l < int1l)
1129 overflow = int2h < hi;
1131 t = build_int_2 (int2l, int2h);
1137 if ((unsigned HOST_WIDE_INT) int1l < int2l)
1140 overflow = int1h < hi;
1142 t = build_int_2 (int1l, int1h);
1145 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1146 t = build_int_2 (low, hi);
1150 if (int2h == 0 && int2l == 0)
1152 t = build_int_2 (int1l, int1h);
1155 neg_double (int2l, int2h, &low, &hi);
1156 add_double (int1l, int1h, low, hi, &low, &hi);
1157 overflow = overflow_sum_sign (hi, int2h, int1h);
1158 t = build_int_2 (low, hi);
1162 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1163 t = build_int_2 (low, hi);
1166 case TRUNC_DIV_EXPR:
1167 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1168 case EXACT_DIV_EXPR:
1169 /* This is a shortcut for a common special case.
1170 It reduces the number of tree nodes generated
1172 if (int2h == 0 && int2l > 0
1173 && TREE_TYPE (arg1) == sizetype
1174 && ! TREE_CONSTANT_OVERFLOW (arg1)
1175 && ! TREE_CONSTANT_OVERFLOW (arg2)
1176 && int1h == 0 && int1l >= 0)
1178 if (code == CEIL_DIV_EXPR)
1180 return size_int (int1l / int2l);
1182 case ROUND_DIV_EXPR:
1183 if (int2h == 0 && int2l == 1)
1185 t = build_int_2 (int1l, int1h);
1188 if (int1l == int2l && int1h == int2h)
1190 if ((int1l | int1h) == 0)
1192 t = build_int_2 (1, 0);
1195 overflow = div_and_round_double (code, uns,
1196 int1l, int1h, int2l, int2h,
1197 &low, &hi, &garbagel, &garbageh);
1198 t = build_int_2 (low, hi);
1201 case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR:
1202 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1203 overflow = div_and_round_double (code, uns,
1204 int1l, int1h, int2l, int2h,
1205 &garbagel, &garbageh, &low, &hi);
1206 t = build_int_2 (low, hi);
1213 low = (((unsigned HOST_WIDE_INT) int1h
1214 < (unsigned HOST_WIDE_INT) int2h)
1215 || (((unsigned HOST_WIDE_INT) int1h
1216 == (unsigned HOST_WIDE_INT) int2h)
1217 && ((unsigned HOST_WIDE_INT) int1l
1218 < (unsigned HOST_WIDE_INT) int2l)));
1222 low = ((int1h < int2h)
1223 || ((int1h == int2h)
1224 && ((unsigned HOST_WIDE_INT) int1l
1225 < (unsigned HOST_WIDE_INT) int2l)));
1227 if (low == (code == MIN_EXPR))
1228 t = build_int_2 (int1l, int1h);
1230 t = build_int_2 (int2l, int2h);
1237 TREE_TYPE (t) = TREE_TYPE (arg1);
1239 = ((notrunc ? !uns && overflow : force_fit_type (t, overflow && !uns))
1240 | TREE_OVERFLOW (arg1)
1241 | TREE_OVERFLOW (arg2));
1242 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1243 | TREE_CONSTANT_OVERFLOW (arg1)
1244 | TREE_CONSTANT_OVERFLOW (arg2));
1247 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1248 if (TREE_CODE (arg1) == REAL_CST)
1253 REAL_VALUE_TYPE value;
1256 d1 = TREE_REAL_CST (arg1);
1257 d2 = TREE_REAL_CST (arg2);
1259 /* If either operand is a NaN, just return it. Otherwise, set up
1260 for floating-point trap; we return an overflow. */
1261 if (REAL_VALUE_ISNAN (d1))
1263 else if (REAL_VALUE_ISNAN (d2))
1265 else if (setjmp (float_error))
1267 t = copy_node (arg1);
1272 set_float_handler (float_error);
1274 #ifdef REAL_ARITHMETIC
1275 REAL_ARITHMETIC (value, code, d1, d2);
1292 #ifndef REAL_INFINITY
1301 value = MIN (d1, d2);
1305 value = MAX (d1, d2);
1311 #endif /* no REAL_ARITHMETIC */
1312 t = build_real (TREE_TYPE (arg1),
1313 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1315 set_float_handler (NULL_PTR);
1318 = (force_fit_type (t, overflow)
1319 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1320 TREE_CONSTANT_OVERFLOW (t)
1322 | TREE_CONSTANT_OVERFLOW (arg1)
1323 | TREE_CONSTANT_OVERFLOW (arg2);
1326 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1327 if (TREE_CODE (arg1) == COMPLEX_CST)
1329 register tree type = TREE_TYPE (arg1);
1330 register tree r1 = TREE_REALPART (arg1);
1331 register tree i1 = TREE_IMAGPART (arg1);
1332 register tree r2 = TREE_REALPART (arg2);
1333 register tree i2 = TREE_IMAGPART (arg2);
1339 t = build_complex (type,
1340 const_binop (PLUS_EXPR, r1, r2, notrunc),
1341 const_binop (PLUS_EXPR, i1, i2, notrunc));
1345 t = build_complex (type,
1346 const_binop (MINUS_EXPR, r1, r2, notrunc),
1347 const_binop (MINUS_EXPR, i1, i2, notrunc));
1351 t = build_complex (type,
1352 const_binop (MINUS_EXPR,
1353 const_binop (MULT_EXPR,
1355 const_binop (MULT_EXPR,
1358 const_binop (PLUS_EXPR,
1359 const_binop (MULT_EXPR,
1361 const_binop (MULT_EXPR,
1368 register tree magsquared
1369 = const_binop (PLUS_EXPR,
1370 const_binop (MULT_EXPR, r2, r2, notrunc),
1371 const_binop (MULT_EXPR, i2, i2, notrunc),
1374 t = build_complex (type,
1376 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1377 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1378 const_binop (PLUS_EXPR,
1379 const_binop (MULT_EXPR, r1, r2,
1381 const_binop (MULT_EXPR, i1, i2,
1384 magsquared, notrunc),
1386 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1387 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1388 const_binop (MINUS_EXPR,
1389 const_binop (MULT_EXPR, i1, r2,
1391 const_binop (MULT_EXPR, r1, i2,
1394 magsquared, notrunc));
1406 /* Return an INTEGER_CST with value V and type from `sizetype'. */
1410 unsigned HOST_WIDE_INT number;
1413 /* Type-size nodes already made for small sizes. */
1414 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1416 if (number < 2*HOST_BITS_PER_WIDE_INT + 1
1417 && size_table[number] != 0)
1418 return size_table[number];
1419 if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
1421 push_obstacks_nochange ();
1422 /* Make this a permanent node. */
1423 end_temporary_allocation ();
1424 t = build_int_2 (number, 0);
1425 TREE_TYPE (t) = sizetype;
1426 size_table[number] = t;
1431 t = build_int_2 (number, 0);
1432 TREE_TYPE (t) = sizetype;
1437 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1438 CODE is a tree code. Data type is taken from `sizetype',
1439 If the operands are constant, so is the result. */
1442 size_binop (code, arg0, arg1)
1443 enum tree_code code;
1446 /* Handle the special case of two integer constants faster. */
1447 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1449 /* And some specific cases even faster than that. */
1450 if (code == PLUS_EXPR && integer_zerop (arg0))
1452 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1453 && integer_zerop (arg1))
1455 else if (code == MULT_EXPR && integer_onep (arg0))
1458 /* Handle general case of two integer constants. */
1459 return const_binop (code, arg0, arg1, 0);
1462 if (arg0 == error_mark_node || arg1 == error_mark_node)
1463 return error_mark_node;
1465 return fold (build (code, sizetype, arg0, arg1));
1468 /* Given T, a tree representing type conversion of ARG1, a constant,
1469 return a constant tree representing the result of conversion. */
1472 fold_convert (t, arg1)
1476 register tree type = TREE_TYPE (t);
1479 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1481 if (TREE_CODE (arg1) == INTEGER_CST)
1483 /* If we would build a constant wider than GCC supports,
1484 leave the conversion unfolded. */
1485 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1488 /* Given an integer constant, make new constant with new type,
1489 appropriately sign-extended or truncated. */
1490 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1491 TREE_INT_CST_HIGH (arg1));
1492 TREE_TYPE (t) = type;
1493 /* Indicate an overflow if (1) ARG1 already overflowed,
1494 or (2) force_fit_type indicates an overflow.
1495 Tell force_fit_type that an overflow has already occurred
1496 if ARG1 is a too-large unsigned value and T is signed. */
1498 = (TREE_OVERFLOW (arg1)
1499 | force_fit_type (t,
1500 (TREE_INT_CST_HIGH (arg1) < 0
1501 & (TREE_UNSIGNED (type)
1502 < TREE_UNSIGNED (TREE_TYPE (arg1))))));
1503 TREE_CONSTANT_OVERFLOW (t)
1504 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1506 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1507 else if (TREE_CODE (arg1) == REAL_CST)
1509 /* Don't initialize these, use assignments.
1510 Initialized local aggregates don't work on old compilers. */
1514 tree type1 = TREE_TYPE (arg1);
1516 x = TREE_REAL_CST (arg1);
1517 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1518 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1519 /* See if X will be in range after truncation towards 0.
1520 To compensate for truncation, move the bounds away from 0,
1521 but reject if X exactly equals the adjusted bounds. */
1522 #ifdef REAL_ARITHMETIC
1523 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1524 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1529 /* If X is a NaN, use zero instead and show we have an overflow.
1530 Otherwise, range check. */
1531 if (REAL_VALUE_ISNAN (x))
1532 overflow = 1, x = dconst0;
1533 else if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
1536 #ifndef REAL_ARITHMETIC
1538 HOST_WIDE_INT low, high;
1539 HOST_WIDE_INT half_word
1540 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1545 high = (HOST_WIDE_INT) (x / half_word / half_word);
1546 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1547 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1549 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1550 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1553 low = (HOST_WIDE_INT) x;
1554 if (TREE_REAL_CST (arg1) < 0)
1555 neg_double (low, high, &low, &high);
1556 t = build_int_2 (low, high);
1560 HOST_WIDE_INT low, high;
1561 REAL_VALUE_TO_INT (&low, &high, x);
1562 t = build_int_2 (low, high);
1565 TREE_TYPE (t) = type;
1567 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1568 TREE_CONSTANT_OVERFLOW (t)
1569 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1571 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1572 TREE_TYPE (t) = type;
1574 else if (TREE_CODE (type) == REAL_TYPE)
1576 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1577 if (TREE_CODE (arg1) == INTEGER_CST)
1578 return build_real_from_int_cst (type, arg1);
1579 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1580 if (TREE_CODE (arg1) == REAL_CST)
1582 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1585 TREE_TYPE (arg1) = type;
1588 else if (setjmp (float_error))
1591 t = copy_node (arg1);
1594 set_float_handler (float_error);
1596 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1597 TREE_REAL_CST (arg1)));
1598 set_float_handler (NULL_PTR);
1602 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1603 TREE_CONSTANT_OVERFLOW (t)
1604 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1608 TREE_CONSTANT (t) = 1;
1612 /* Return an expr equal to X but certainly not valid as an lvalue.
1613 Also make sure it is not valid as an null pointer constant. */
1621 /* These things are certainly not lvalues. */
1622 if (TREE_CODE (x) == NON_LVALUE_EXPR
1623 || TREE_CODE (x) == INTEGER_CST
1624 || TREE_CODE (x) == REAL_CST
1625 || TREE_CODE (x) == STRING_CST
1626 || TREE_CODE (x) == ADDR_EXPR)
1628 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1630 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1631 so convert_for_assignment won't strip it.
1632 This is so this 0 won't be treated as a null pointer constant. */
1633 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1634 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1640 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1641 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1645 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1646 Zero means allow extended lvalues. */
1648 int pedantic_lvalues;
1650 /* When pedantic, return an expr equal to X but certainly not valid as a
1651 pedantic lvalue. Otherwise, return X. */
1654 pedantic_non_lvalue (x)
1657 if (pedantic_lvalues)
1658 return non_lvalue (x);
1663 /* Given a tree comparison code, return the code that is the logical inverse
1664 of the given code. It is not safe to do this for floating-point
1665 comparisons, except for NE_EXPR and EQ_EXPR. */
1667 static enum tree_code
1668 invert_tree_comparison (code)
1669 enum tree_code code;
1690 /* Similar, but return the comparison that results if the operands are
1691 swapped. This is safe for floating-point. */
1693 static enum tree_code
1694 swap_tree_comparison (code)
1695 enum tree_code code;
1715 /* Return nonzero if CODE is a tree code that represents a truth value. */
1718 truth_value_p (code)
1719 enum tree_code code;
1721 return (TREE_CODE_CLASS (code) == '<'
1722 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1723 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1724 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1727 /* Return nonzero if two operands are necessarily equal.
1728 If ONLY_CONST is non-zero, only return non-zero for constants.
1729 This function tests whether the operands are indistinguishable;
1730 it does not test whether they are equal using C's == operation.
1731 The distinction is important for IEEE floating point, because
1732 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1733 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1736 operand_equal_p (arg0, arg1, only_const)
1740 /* If both types don't have the same signedness, then we can't consider
1741 them equal. We must check this before the STRIP_NOPS calls
1742 because they may change the signedness of the arguments. */
1743 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1749 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1750 We don't care about side effects in that case because the SAVE_EXPR
1751 takes care of that for us. */
1752 if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1)
1753 return ! only_const;
1755 if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))
1758 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1759 && TREE_CODE (arg0) == ADDR_EXPR
1760 && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0))
1763 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1764 && TREE_CODE (arg0) == INTEGER_CST
1765 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1766 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1))
1769 /* Detect when real constants are equal. */
1770 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1771 && TREE_CODE (arg0) == REAL_CST)
1772 return REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), TREE_REAL_CST (arg1));
1780 if (TREE_CODE (arg0) != TREE_CODE (arg1))
1782 /* This is needed for conversions and for COMPONENT_REF.
1783 Might as well play it safe and always test this. */
1784 if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1787 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1790 /* Two conversions are equal only if signedness and modes match. */
1791 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1792 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1793 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1796 return operand_equal_p (TREE_OPERAND (arg0, 0),
1797 TREE_OPERAND (arg1, 0), 0);
1801 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1802 TREE_OPERAND (arg1, 0), 0)
1803 && operand_equal_p (TREE_OPERAND (arg0, 1),
1804 TREE_OPERAND (arg1, 1), 0));
1807 switch (TREE_CODE (arg0))
1810 return operand_equal_p (TREE_OPERAND (arg0, 0),
1811 TREE_OPERAND (arg1, 0), 0);
1815 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1816 TREE_OPERAND (arg1, 0), 0)
1817 && operand_equal_p (TREE_OPERAND (arg0, 1),
1818 TREE_OPERAND (arg1, 1), 0));
1821 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1822 TREE_OPERAND (arg1, 0), 0)
1823 && operand_equal_p (TREE_OPERAND (arg0, 1),
1824 TREE_OPERAND (arg1, 1), 0)
1825 && operand_equal_p (TREE_OPERAND (arg0, 2),
1826 TREE_OPERAND (arg1, 2), 0));
1834 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1835 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1837 When in doubt, return 0. */
1840 operand_equal_for_comparison_p (arg0, arg1, other)
1844 int unsignedp1, unsignedpo;
1845 tree primarg1, primother;
1846 unsigned correct_width;
1848 if (operand_equal_p (arg0, arg1, 0))
1851 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1852 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1855 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1856 actual comparison operand, ARG0.
1858 First throw away any conversions to wider types
1859 already present in the operands. */
1861 primarg1 = get_narrower (arg1, &unsignedp1);
1862 primother = get_narrower (other, &unsignedpo);
1864 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1865 if (unsignedp1 == unsignedpo
1866 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1867 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1869 tree type = TREE_TYPE (arg0);
1871 /* Make sure shorter operand is extended the right way
1872 to match the longer operand. */
1873 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1874 TREE_TYPE (primarg1)),
1877 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1884 /* See if ARG is an expression that is either a comparison or is performing
1885 arithmetic on comparisons. The comparisons must only be comparing
1886 two different values, which will be stored in *CVAL1 and *CVAL2; if
1887 they are non-zero it means that some operands have already been found.
1888 No variables may be used anywhere else in the expression except in the
1889 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1890 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1892 If this is true, return 1. Otherwise, return zero. */
1895 twoval_comparison_p (arg, cval1, cval2, save_p)
1897 tree *cval1, *cval2;
1900 enum tree_code code = TREE_CODE (arg);
1901 char class = TREE_CODE_CLASS (code);
1903 /* We can handle some of the 'e' cases here. */
1904 if (class == 'e' && code == TRUTH_NOT_EXPR)
1906 else if (class == 'e'
1907 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1908 || code == COMPOUND_EXPR))
1911 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1912 the expression. There may be no way to make this work, but it needs
1913 to be looked at again for 2.6. */
1915 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1917 /* If we've already found a CVAL1 or CVAL2, this expression is
1918 two complex to handle. */
1919 if (*cval1 || *cval2)
1930 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
1933 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
1934 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1935 cval1, cval2, save_p));
1941 if (code == COND_EXPR)
1942 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
1943 cval1, cval2, save_p)
1944 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1945 cval1, cval2, save_p)
1946 && twoval_comparison_p (TREE_OPERAND (arg, 2),
1947 cval1, cval2, save_p));
1951 /* First see if we can handle the first operand, then the second. For
1952 the second operand, we know *CVAL1 can't be zero. It must be that
1953 one side of the comparison is each of the values; test for the
1954 case where this isn't true by failing if the two operands
1957 if (operand_equal_p (TREE_OPERAND (arg, 0),
1958 TREE_OPERAND (arg, 1), 0))
1962 *cval1 = TREE_OPERAND (arg, 0);
1963 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
1965 else if (*cval2 == 0)
1966 *cval2 = TREE_OPERAND (arg, 0);
1967 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
1972 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
1974 else if (*cval2 == 0)
1975 *cval2 = TREE_OPERAND (arg, 1);
1976 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
1987 /* ARG is a tree that is known to contain just arithmetic operations and
1988 comparisons. Evaluate the operations in the tree substituting NEW0 for
1989 any occurrence of OLD0 as an operand of a comparison and likewise for
1993 eval_subst (arg, old0, new0, old1, new1)
1995 tree old0, new0, old1, new1;
1997 tree type = TREE_TYPE (arg);
1998 enum tree_code code = TREE_CODE (arg);
1999 char class = TREE_CODE_CLASS (code);
2001 /* We can handle some of the 'e' cases here. */
2002 if (class == 'e' && code == TRUTH_NOT_EXPR)
2004 else if (class == 'e'
2005 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2011 return fold (build1 (code, type,
2012 eval_subst (TREE_OPERAND (arg, 0),
2013 old0, new0, old1, new1)));
2016 return fold (build (code, type,
2017 eval_subst (TREE_OPERAND (arg, 0),
2018 old0, new0, old1, new1),
2019 eval_subst (TREE_OPERAND (arg, 1),
2020 old0, new0, old1, new1)));
2026 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2029 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2032 return fold (build (code, type,
2033 eval_subst (TREE_OPERAND (arg, 0),
2034 old0, new0, old1, new1),
2035 eval_subst (TREE_OPERAND (arg, 1),
2036 old0, new0, old1, new1),
2037 eval_subst (TREE_OPERAND (arg, 2),
2038 old0, new0, old1, new1)));
2043 tree arg0 = TREE_OPERAND (arg, 0);
2044 tree arg1 = TREE_OPERAND (arg, 1);
2046 /* We need to check both for exact equality and tree equality. The
2047 former will be true if the operand has a side-effect. In that
2048 case, we know the operand occurred exactly once. */
2050 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2052 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2055 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2057 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2060 return fold (build (code, type, arg0, arg1));
2067 /* Return a tree for the case when the result of an expression is RESULT
2068 converted to TYPE and OMITTED was previously an operand of the expression
2069 but is now not needed (e.g., we folded OMITTED * 0).
2071 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2072 the conversion of RESULT to TYPE. */
2075 omit_one_operand (type, result, omitted)
2076 tree type, result, omitted;
2078 tree t = convert (type, result);
2080 if (TREE_SIDE_EFFECTS (omitted))
2081 return build (COMPOUND_EXPR, type, omitted, t);
2083 return non_lvalue (t);
2086 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2089 pedantic_omit_one_operand (type, result, omitted)
2090 tree type, result, omitted;
2092 tree t = convert (type, result);
2094 if (TREE_SIDE_EFFECTS (omitted))
2095 return build (COMPOUND_EXPR, type, omitted, t);
2097 return pedantic_non_lvalue (t);
2102 /* Return a simplified tree node for the truth-negation of ARG. This
2103 never alters ARG itself. We assume that ARG is an operation that
2104 returns a truth value (0 or 1). */
2107 invert_truthvalue (arg)
2110 tree type = TREE_TYPE (arg);
2111 enum tree_code code = TREE_CODE (arg);
2113 if (code == ERROR_MARK)
2116 /* If this is a comparison, we can simply invert it, except for
2117 floating-point non-equality comparisons, in which case we just
2118 enclose a TRUTH_NOT_EXPR around what we have. */
2120 if (TREE_CODE_CLASS (code) == '<')
2122 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2123 && code != NE_EXPR && code != EQ_EXPR)
2124 return build1 (TRUTH_NOT_EXPR, type, arg);
2126 return build (invert_tree_comparison (code), type,
2127 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2133 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2134 && TREE_INT_CST_HIGH (arg) == 0, 0));
2136 case TRUTH_AND_EXPR:
2137 return build (TRUTH_OR_EXPR, type,
2138 invert_truthvalue (TREE_OPERAND (arg, 0)),
2139 invert_truthvalue (TREE_OPERAND (arg, 1)));
2142 return build (TRUTH_AND_EXPR, type,
2143 invert_truthvalue (TREE_OPERAND (arg, 0)),
2144 invert_truthvalue (TREE_OPERAND (arg, 1)));
2146 case TRUTH_XOR_EXPR:
2147 /* Here we can invert either operand. We invert the first operand
2148 unless the second operand is a TRUTH_NOT_EXPR in which case our
2149 result is the XOR of the first operand with the inside of the
2150 negation of the second operand. */
2152 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2153 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2154 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2156 return build (TRUTH_XOR_EXPR, type,
2157 invert_truthvalue (TREE_OPERAND (arg, 0)),
2158 TREE_OPERAND (arg, 1));
2160 case TRUTH_ANDIF_EXPR:
2161 return build (TRUTH_ORIF_EXPR, type,
2162 invert_truthvalue (TREE_OPERAND (arg, 0)),
2163 invert_truthvalue (TREE_OPERAND (arg, 1)));
2165 case TRUTH_ORIF_EXPR:
2166 return build (TRUTH_ANDIF_EXPR, type,
2167 invert_truthvalue (TREE_OPERAND (arg, 0)),
2168 invert_truthvalue (TREE_OPERAND (arg, 1)));
2170 case TRUTH_NOT_EXPR:
2171 return TREE_OPERAND (arg, 0);
2174 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2175 invert_truthvalue (TREE_OPERAND (arg, 1)),
2176 invert_truthvalue (TREE_OPERAND (arg, 2)));
2179 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2180 invert_truthvalue (TREE_OPERAND (arg, 1)));
2182 case NON_LVALUE_EXPR:
2183 return invert_truthvalue (TREE_OPERAND (arg, 0));
2188 return build1 (TREE_CODE (arg), type,
2189 invert_truthvalue (TREE_OPERAND (arg, 0)));
2192 if (!integer_onep (TREE_OPERAND (arg, 1)))
2194 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2197 return build1 (TRUTH_NOT_EXPR, type, arg);
2199 case CLEANUP_POINT_EXPR:
2200 return build1 (CLEANUP_POINT_EXPR, type,
2201 invert_truthvalue (TREE_OPERAND (arg, 0)));
2203 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2205 return build1 (TRUTH_NOT_EXPR, type, arg);
2208 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2209 operands are another bit-wise operation with a common input. If so,
2210 distribute the bit operations to save an operation and possibly two if
2211 constants are involved. For example, convert
2212 (A | B) & (A | C) into A | (B & C)
2213 Further simplification will occur if B and C are constants.
2215 If this optimization cannot be done, 0 will be returned. */
2218 distribute_bit_expr (code, type, arg0, arg1)
2219 enum tree_code code;
2226 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2227 || TREE_CODE (arg0) == code
2228 || (TREE_CODE (arg0) != BIT_AND_EXPR
2229 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2232 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2234 common = TREE_OPERAND (arg0, 0);
2235 left = TREE_OPERAND (arg0, 1);
2236 right = TREE_OPERAND (arg1, 1);
2238 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2240 common = TREE_OPERAND (arg0, 0);
2241 left = TREE_OPERAND (arg0, 1);
2242 right = TREE_OPERAND (arg1, 0);
2244 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2246 common = TREE_OPERAND (arg0, 1);
2247 left = TREE_OPERAND (arg0, 0);
2248 right = TREE_OPERAND (arg1, 1);
2250 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2252 common = TREE_OPERAND (arg0, 1);
2253 left = TREE_OPERAND (arg0, 0);
2254 right = TREE_OPERAND (arg1, 0);
2259 return fold (build (TREE_CODE (arg0), type, common,
2260 fold (build (code, type, left, right))));
2263 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2264 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2267 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2270 int bitsize, bitpos;
2273 tree result = build (BIT_FIELD_REF, type, inner,
2274 size_int (bitsize), size_int (bitpos));
2276 TREE_UNSIGNED (result) = unsignedp;
2281 /* Optimize a bit-field compare.
2283 There are two cases: First is a compare against a constant and the
2284 second is a comparison of two items where the fields are at the same
2285 bit position relative to the start of a chunk (byte, halfword, word)
2286 large enough to contain it. In these cases we can avoid the shift
2287 implicit in bitfield extractions.
2289 For constants, we emit a compare of the shifted constant with the
2290 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2291 compared. For two fields at the same position, we do the ANDs with the
2292 similar mask and compare the result of the ANDs.
2294 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2295 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2296 are the left and right operands of the comparison, respectively.
2298 If the optimization described above can be done, we return the resulting
2299 tree. Otherwise we return zero. */
2302 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2303 enum tree_code code;
2307 int lbitpos, lbitsize, rbitpos, rbitsize;
2308 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2309 tree type = TREE_TYPE (lhs);
2310 tree signed_type, unsigned_type;
2311 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2312 enum machine_mode lmode, rmode, lnmode, rnmode;
2313 int lunsignedp, runsignedp;
2314 int lvolatilep = 0, rvolatilep = 0;
2315 tree linner, rinner;
2319 /* Get all the information about the extractions being done. If the bit size
2320 if the same as the size of the underlying object, we aren't doing an
2321 extraction at all and so can do nothing. */
2322 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2323 &lunsignedp, &lvolatilep);
2324 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2330 /* If this is not a constant, we can only do something if bit positions,
2331 sizes, and signedness are the same. */
2332 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset,
2333 &rmode, &runsignedp, &rvolatilep);
2335 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2336 || lunsignedp != runsignedp || offset != 0)
2340 /* See if we can find a mode to refer to this field. We should be able to,
2341 but fail if we can't. */
2342 lnmode = get_best_mode (lbitsize, lbitpos,
2343 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2345 if (lnmode == VOIDmode)
2348 /* Set signed and unsigned types of the precision of this mode for the
2350 signed_type = type_for_mode (lnmode, 0);
2351 unsigned_type = type_for_mode (lnmode, 1);
2355 rnmode = get_best_mode (rbitsize, rbitpos,
2356 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2358 if (rnmode == VOIDmode)
2362 /* Compute the bit position and size for the new reference and our offset
2363 within it. If the new reference is the same size as the original, we
2364 won't optimize anything, so return zero. */
2365 lnbitsize = GET_MODE_BITSIZE (lnmode);
2366 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2367 lbitpos -= lnbitpos;
2368 if (lnbitsize == lbitsize)
2373 rnbitsize = GET_MODE_BITSIZE (rnmode);
2374 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2375 rbitpos -= rnbitpos;
2376 if (rnbitsize == rbitsize)
2380 if (BYTES_BIG_ENDIAN)
2381 lbitpos = lnbitsize - lbitsize - lbitpos;
2383 /* Make the mask to be used against the extracted field. */
2384 mask = build_int_2 (~0, ~0);
2385 TREE_TYPE (mask) = unsigned_type;
2386 force_fit_type (mask, 0);
2387 mask = convert (unsigned_type, mask);
2388 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2389 mask = const_binop (RSHIFT_EXPR, mask,
2390 size_int (lnbitsize - lbitsize - lbitpos), 0);
2393 /* If not comparing with constant, just rework the comparison
2395 return build (code, compare_type,
2396 build (BIT_AND_EXPR, unsigned_type,
2397 make_bit_field_ref (linner, unsigned_type,
2398 lnbitsize, lnbitpos, 1),
2400 build (BIT_AND_EXPR, unsigned_type,
2401 make_bit_field_ref (rinner, unsigned_type,
2402 rnbitsize, rnbitpos, 1),
2405 /* Otherwise, we are handling the constant case. See if the constant is too
2406 big for the field. Warn and return a tree of for 0 (false) if so. We do
2407 this not only for its own sake, but to avoid having to test for this
2408 error case below. If we didn't, we might generate wrong code.
2410 For unsigned fields, the constant shifted right by the field length should
2411 be all zero. For signed fields, the high-order bits should agree with
2416 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2417 convert (unsigned_type, rhs),
2418 size_int (lbitsize), 0)))
2420 warning ("comparison is always %s due to width of bitfield",
2421 code == NE_EXPR ? "one" : "zero");
2422 return convert (compare_type,
2424 ? integer_one_node : integer_zero_node));
2429 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2430 size_int (lbitsize - 1), 0);
2431 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2433 warning ("comparison is always %s due to width of bitfield",
2434 code == NE_EXPR ? "one" : "zero");
2435 return convert (compare_type,
2437 ? integer_one_node : integer_zero_node));
2441 /* Single-bit compares should always be against zero. */
2442 if (lbitsize == 1 && ! integer_zerop (rhs))
2444 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2445 rhs = convert (type, integer_zero_node);
2448 /* Make a new bitfield reference, shift the constant over the
2449 appropriate number of bits and mask it with the computed mask
2450 (in case this was a signed field). If we changed it, make a new one. */
2451 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2454 TREE_SIDE_EFFECTS (lhs) = 1;
2455 TREE_THIS_VOLATILE (lhs) = 1;
2458 rhs = fold (const_binop (BIT_AND_EXPR,
2459 const_binop (LSHIFT_EXPR,
2460 convert (unsigned_type, rhs),
2461 size_int (lbitpos), 0),
2464 return build (code, compare_type,
2465 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2469 /* Subroutine for fold_truthop: decode a field reference.
2471 If EXP is a comparison reference, we return the innermost reference.
2473 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2474 set to the starting bit number.
2476 If the innermost field can be completely contained in a mode-sized
2477 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2479 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2480 otherwise it is not changed.
2482 *PUNSIGNEDP is set to the signedness of the field.
2484 *PMASK is set to the mask used. This is either contained in a
2485 BIT_AND_EXPR or derived from the width of the field.
2487 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2489 Return 0 if this is not a component reference or is one that we can't
2490 do anything with. */
2493 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2494 pvolatilep, pmask, pand_mask)
2496 int *pbitsize, *pbitpos;
2497 enum machine_mode *pmode;
2498 int *punsignedp, *pvolatilep;
2503 tree mask, inner, offset;
2507 /* All the optimizations using this function assume integer fields.
2508 There are problems with FP fields since the type_for_size call
2509 below can fail for, e.g., XFmode. */
2510 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2515 if (TREE_CODE (exp) == BIT_AND_EXPR)
2517 and_mask = TREE_OPERAND (exp, 1);
2518 exp = TREE_OPERAND (exp, 0);
2519 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2520 if (TREE_CODE (and_mask) != INTEGER_CST)
2525 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2526 punsignedp, pvolatilep);
2527 if ((inner == exp && and_mask == 0)
2528 || *pbitsize < 0 || offset != 0)
2531 /* Compute the mask to access the bitfield. */
2532 unsigned_type = type_for_size (*pbitsize, 1);
2533 precision = TYPE_PRECISION (unsigned_type);
2535 mask = build_int_2 (~0, ~0);
2536 TREE_TYPE (mask) = unsigned_type;
2537 force_fit_type (mask, 0);
2538 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2539 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2541 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2543 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2544 convert (unsigned_type, and_mask), mask));
2547 *pand_mask = and_mask;
2551 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2555 all_ones_mask_p (mask, size)
2559 tree type = TREE_TYPE (mask);
2560 int precision = TYPE_PRECISION (type);
2563 tmask = build_int_2 (~0, ~0);
2564 TREE_TYPE (tmask) = signed_type (type);
2565 force_fit_type (tmask, 0);
2567 tree_int_cst_equal (mask,
2568 const_binop (RSHIFT_EXPR,
2569 const_binop (LSHIFT_EXPR, tmask,
2570 size_int (precision - size),
2572 size_int (precision - size), 0));
2575 /* Subroutine for fold_truthop: determine if an operand is simple enough
2576 to be evaluated unconditionally. */
2579 simple_operand_p (exp)
2582 /* Strip any conversions that don't change the machine mode. */
2583 while ((TREE_CODE (exp) == NOP_EXPR
2584 || TREE_CODE (exp) == CONVERT_EXPR)
2585 && (TYPE_MODE (TREE_TYPE (exp))
2586 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2587 exp = TREE_OPERAND (exp, 0);
2589 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2590 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2591 && ! TREE_ADDRESSABLE (exp)
2592 && ! TREE_THIS_VOLATILE (exp)
2593 && ! DECL_NONLOCAL (exp)
2594 /* Don't regard global variables as simple. They may be
2595 allocated in ways unknown to the compiler (shared memory,
2596 #pragma weak, etc). */
2597 && ! TREE_PUBLIC (exp)
2598 && ! DECL_EXTERNAL (exp)
2599 /* Loading a static variable is unduly expensive, but global
2600 registers aren't expensive. */
2601 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2604 /* The following functions are subroutines to fold_range_test and allow it to
2605 try to change a logical combination of comparisons into a range test.
2608 X == 2 && X == 3 && X == 4 && X == 5
2612 (unsigned) (X - 2) <= 3
2614 We decribe each set of comparisons as being either inside or outside
2615 a range, using a variable named like IN_P, and then describe the
2616 range with a lower and upper bound. If one of the bounds is omitted,
2617 it represents either the highest or lowest value of the type.
2619 In the comments below, we represent a range by two numbers in brackets
2620 preceeded by a "+" to designate being inside that range, or a "-" to
2621 designate being outside that range, so the condition can be inverted by
2622 flipping the prefix. An omitted bound is represented by a "-". For
2623 example, "- [-, 10]" means being outside the range starting at the lowest
2624 possible value and ending at 10, in other words, being greater than 10.
2625 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2628 We set up things so that the missing bounds are handled in a consistent
2629 manner so neither a missing bound nor "true" and "false" need to be
2630 handled using a special case. */
2632 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2633 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2634 and UPPER1_P are nonzero if the respective argument is an upper bound
2635 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2636 must be specified for a comparison. ARG1 will be converted to ARG0's
2637 type if both are specified. */
2640 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2641 enum tree_code code;
2644 int upper0_p, upper1_p;
2650 /* If neither arg represents infinity, do the normal operation.
2651 Else, if not a comparison, return infinity. Else handle the special
2652 comparison rules. Note that most of the cases below won't occur, but
2653 are handled for consistency. */
2655 if (arg0 != 0 && arg1 != 0)
2657 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2658 arg0, convert (TREE_TYPE (arg0), arg1)));
2660 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2663 if (TREE_CODE_CLASS (code) != '<')
2666 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2667 for neither. Then compute our result treating them as never equal
2668 and comparing bounds to non-bounds as above. */
2669 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2670 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2673 case EQ_EXPR: case NE_EXPR:
2674 result = (code == NE_EXPR);
2676 case LT_EXPR: case LE_EXPR:
2677 result = sgn0 < sgn1;
2679 case GT_EXPR: case GE_EXPR:
2680 result = sgn0 > sgn1;
2684 return convert (type, result ? integer_one_node : integer_zero_node);
2687 /* Given EXP, a logical expression, set the range it is testing into
2688 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2689 actually being tested. *PLOW and *PHIGH will have be made the same type
2690 as the returned expression. If EXP is not a comparison, we will most
2691 likely not be returning a useful value and range. */
2694 make_range (exp, pin_p, plow, phigh)
2699 enum tree_code code;
2700 tree arg0, arg1, type;
2702 tree low, high, n_low, n_high;
2704 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2705 and see if we can refine the range. Some of the cases below may not
2706 happen, but it doesn't seem worth worrying about this. We "continue"
2707 the outer loop when we've changed something; otherwise we "break"
2708 the switch, which will "break" the while. */
2710 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2714 code = TREE_CODE (exp);
2715 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2716 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2717 || TREE_CODE_CLASS (code) == '2')
2718 type = TREE_TYPE (arg0);
2722 case TRUTH_NOT_EXPR:
2723 in_p = ! in_p, exp = arg0;
2726 case EQ_EXPR: case NE_EXPR:
2727 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2728 /* We can only do something if the range is testing for zero
2729 and if the second operand is an integer constant. Note that
2730 saying something is "in" the range we make is done by
2731 complementing IN_P since it will set in the initial case of
2732 being not equal to zero; "out" is leaving it alone. */
2733 if (low == 0 || high == 0
2734 || ! integer_zerop (low) || ! integer_zerop (high)
2735 || TREE_CODE (arg1) != INTEGER_CST)
2740 case NE_EXPR: /* - [c, c] */
2743 case EQ_EXPR: /* + [c, c] */
2744 in_p = ! in_p, low = high = arg1;
2746 case GT_EXPR: /* - [-, c] */
2747 low = 0, high = arg1;
2749 case GE_EXPR: /* + [c, -] */
2750 in_p = ! in_p, low = arg1, high = 0;
2752 case LT_EXPR: /* - [c, -] */
2753 low = arg1, high = 0;
2755 case LE_EXPR: /* + [-, c] */
2756 in_p = ! in_p, low = 0, high = arg1;
2762 /* If this is an unsigned comparison, we also know that EXP is
2763 greater than or equal to zero. We base the range tests we make
2764 on that fact, so we record it here so we can parse existing
2766 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2768 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2769 1, convert (type, integer_zero_node),
2773 in_p = n_in_p, low = n_low, high = n_high;
2775 /* If the high bound is missing, reverse the range so it
2776 goes from zero to the low bound minus 1. */
2780 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2781 integer_one_node, 0);
2782 low = convert (type, integer_zero_node);
2788 /* (-x) IN [a,b] -> x in [-b, -a] */
2789 n_low = range_binop (MINUS_EXPR, type,
2790 convert (type, integer_zero_node), 0, high, 1);
2791 n_high = range_binop (MINUS_EXPR, type,
2792 convert (type, integer_zero_node), 0, low, 0);
2793 low = n_low, high = n_high;
2799 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2800 convert (type, integer_one_node));
2803 case PLUS_EXPR: case MINUS_EXPR:
2804 if (TREE_CODE (arg1) != INTEGER_CST)
2807 /* If EXP is signed, any overflow in the computation is undefined,
2808 so we don't worry about it so long as our computations on
2809 the bounds don't overflow. For unsigned, overflow is defined
2810 and this is exactly the right thing. */
2811 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2812 type, low, 0, arg1, 0);
2813 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2814 type, high, 1, arg1, 0);
2815 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2816 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2819 /* Check for an unsigned range which has wrapped around the maximum
2820 value thus making n_high < n_low, and normalize it. */
2821 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2823 low = range_binop (PLUS_EXPR, type, n_high, 0,
2824 integer_one_node, 0);
2825 high = range_binop (MINUS_EXPR, type, n_low, 0,
2826 integer_one_node, 0);
2830 low = n_low, high = n_high;
2835 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2836 if (! INTEGRAL_TYPE_P (type)
2837 || (low != 0 && ! int_fits_type_p (low, type))
2838 || (high != 0 && ! int_fits_type_p (high, type)))
2842 low = convert (type, low);
2845 high = convert (type, high);
2854 /* If EXP is a constant, we can evaluate whether this is true or false. */
2855 if (TREE_CODE (exp) == INTEGER_CST)
2857 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2859 && integer_onep (range_binop (LE_EXPR, integer_type_node,
2865 *pin_p = in_p, *plow = low, *phigh = high;
2869 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
2870 type, TYPE, return an expression to test if EXP is in (or out of, depending
2871 on IN_P) the range. */
2874 build_range_check (type, exp, in_p, low, high)
2880 tree etype = TREE_TYPE (exp);
2884 && (0 != (value = build_range_check (type, exp, 1, low, high))))
2885 return invert_truthvalue (value);
2887 else if (low == 0 && high == 0)
2888 return convert (type, integer_one_node);
2891 return fold (build (LE_EXPR, type, exp, high));
2894 return fold (build (GE_EXPR, type, exp, low));
2896 else if (operand_equal_p (low, high, 0))
2897 return fold (build (EQ_EXPR, type, exp, low));
2899 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
2900 return build_range_check (type, exp, 1, 0, high);
2902 else if (integer_zerop (low))
2904 utype = unsigned_type (etype);
2905 return build_range_check (type, convert (utype, exp), 1, 0,
2906 convert (utype, high));
2909 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
2910 && ! TREE_OVERFLOW (value))
2911 return build_range_check (type,
2912 fold (build (MINUS_EXPR, etype, exp, low)),
2913 1, convert (etype, integer_zero_node), value);
2918 /* Given two ranges, see if we can merge them into one. Return 1 if we
2919 can, 0 if we can't. Set the output range into the specified parameters. */
2922 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
2926 tree low0, high0, low1, high1;
2935 /* Make range 0 be the range that starts first. Swap them if it isn't. */
2936 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
2938 || (((low0 == 0 && low1 == 0)
2939 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
2941 && integer_onep (range_binop (GT_EXPR, integer_type_node,
2942 high0, 1, high1, 1))))
2944 temp = in0_p, in0_p = in1_p, in1_p = temp;
2945 tem = low0, low0 = low1, low1 = tem;
2946 tem = high0, high0 = high1, high1 = tem;
2949 /* Now flag two cases, whether the ranges are disjoint or whether the
2950 second range is totally subsumed in the first. Note that the tests
2951 below are simplified by the ones above. */
2952 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
2953 high0, 1, low1, 0));
2954 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
2955 high1, 1, high0, 1));
2957 /* We now have four cases, depending on whether we are including or
2958 excluding the two ranges. */
2961 /* If they don't overlap, the result is false. If the second range
2962 is a subset it is the result. Otherwise, the range is from the start
2963 of the second to the end of the first. */
2965 in_p = 0, low = high = 0;
2967 in_p = 1, low = low1, high = high1;
2969 in_p = 1, low = low1, high = high0;
2972 else if (in0_p && ! in1_p)
2974 /* If they don't overlap, the result is the first range. If the
2975 second range is a subset of the first, we can't describe this as
2976 a single range unless both ranges end at the same place. If both
2977 ranges also start in the same place, then the result is false.
2978 Otherwise, we go from the start of the first range to just before
2979 the start of the second. */
2981 in_p = 1, low = low0, high = high0;
2983 && integer_zerop (range_binop (EQ_EXPR, integer_type_node,
2984 high0, 1, high1, 0)))
2987 && integer_onep (range_binop (EQ_EXPR, integer_type_node,
2989 in_p = 0, low = high = 0;
2992 in_p = 1, low = low0;
2993 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
2994 integer_one_node, 0);
2998 else if (! in0_p && in1_p)
3000 /* If they don't overlap, the result is the second range. If the second
3001 is a subset of the first, the result is false. Otherwise,
3002 the range starts just after the first range and ends at the
3003 end of the second. */
3005 in_p = 1, low = low1, high = high1;
3007 in_p = 0, low = high = 0;
3010 in_p = 1, high = high1;
3011 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3012 integer_one_node, 0);
3018 /* The case where we are excluding both ranges. Here the complex case
3019 is if they don't overlap. In that case, the only time we have a
3020 range is if they are adjacent. If the second is a subset of the
3021 first, the result is the first. Otherwise, the range to exclude
3022 starts at the beginning of the first range and ends at the end of the
3026 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3027 range_binop (PLUS_EXPR, NULL_TREE,
3029 integer_one_node, 1),
3031 in_p = 0, low = low0, high = high1;
3036 in_p = 0, low = low0, high = high0;
3038 in_p = 0, low = low0, high = high1;
3041 *pin_p = in_p, *plow = low, *phigh = high;
3045 /* EXP is some logical combination of boolean tests. See if we can
3046 merge it into some range test. Return the new tree if so. */
3049 fold_range_test (exp)
3052 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3053 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3054 int in0_p, in1_p, in_p;
3055 tree low0, low1, low, high0, high1, high;
3056 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3057 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3060 /* If this is an OR operation, invert both sides; we will invert
3061 again at the end. */
3063 in0_p = ! in0_p, in1_p = ! in1_p;
3065 /* If both expressions are the same, if we can merge the ranges, and we
3066 can build the range test, return it or it inverted. If one of the
3067 ranges is always true or always false, consider it to be the same
3068 expression as the other. */
3069 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3070 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3072 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3074 : rhs != 0 ? rhs : integer_zero_node,
3076 return or_op ? invert_truthvalue (tem) : tem;
3078 /* On machines where the branch cost is expensive, if this is a
3079 short-circuited branch and the underlying object on both sides
3080 is the same, make a non-short-circuit operation. */
3081 else if (BRANCH_COST >= 2
3082 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3083 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3084 && operand_equal_p (lhs, rhs, 0))
3086 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR. */
3087 if (simple_operand_p (lhs))
3088 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3089 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3090 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3091 TREE_OPERAND (exp, 1));
3094 tree common = save_expr (lhs);
3096 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3097 or_op ? ! in0_p : in0_p,
3099 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3100 or_op ? ! in1_p : in1_p,
3102 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3103 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3104 TREE_TYPE (exp), lhs, rhs);
3111 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3112 bit value. Arrange things so the extra bits will be set to zero if and
3113 only if C is signed-extended to its full width. If MASK is nonzero,
3114 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3117 unextend (c, p, unsignedp, mask)
3123 tree type = TREE_TYPE (c);
3124 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3127 if (p == modesize || unsignedp)
3130 if (TREE_UNSIGNED (type))
3131 c = convert (signed_type (type), c);
3133 /* We work by getting just the sign bit into the low-order bit, then
3134 into the high-order bit, then sign-extend. We then XOR that value
3136 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3137 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3138 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3139 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3141 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3143 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3146 /* Find ways of folding logical expressions of LHS and RHS:
3147 Try to merge two comparisons to the same innermost item.
3148 Look for range tests like "ch >= '0' && ch <= '9'".
3149 Look for combinations of simple terms on machines with expensive branches
3150 and evaluate the RHS unconditionally.
3152 For example, if we have p->a == 2 && p->b == 4 and we can make an
3153 object large enough to span both A and B, we can do this with a comparison
3154 against the object ANDed with the a mask.
3156 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3157 operations to do this with one comparison.
3159 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3160 function and the one above.
3162 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3163 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3165 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3168 We return the simplified tree or 0 if no optimization is possible. */
3171 fold_truthop (code, truth_type, lhs, rhs)
3172 enum tree_code code;
3173 tree truth_type, lhs, rhs;
3175 /* If this is the "or" of two comparisons, we can do something if we
3176 the comparisons are NE_EXPR. If this is the "and", we can do something
3177 if the comparisons are EQ_EXPR. I.e.,
3178 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3180 WANTED_CODE is this operation code. For single bit fields, we can
3181 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3182 comparison for one-bit fields. */
3184 enum tree_code wanted_code;
3185 enum tree_code lcode, rcode;
3186 tree ll_arg, lr_arg, rl_arg, rr_arg;
3187 tree ll_inner, lr_inner, rl_inner, rr_inner;
3188 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3189 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3190 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3191 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3192 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3193 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3194 enum machine_mode lnmode, rnmode;
3195 tree ll_mask, lr_mask, rl_mask, rr_mask;
3196 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3197 tree l_const, r_const;
3199 int first_bit, end_bit;
3202 /* Start by getting the comparison codes. Fail if anything is volatile.
3203 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3204 it were surrounded with a NE_EXPR. */
3206 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3209 lcode = TREE_CODE (lhs);
3210 rcode = TREE_CODE (rhs);
3212 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3213 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3215 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3216 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3218 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3221 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3222 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3224 ll_arg = TREE_OPERAND (lhs, 0);
3225 lr_arg = TREE_OPERAND (lhs, 1);
3226 rl_arg = TREE_OPERAND (rhs, 0);
3227 rr_arg = TREE_OPERAND (rhs, 1);
3229 /* If the RHS can be evaluated unconditionally and its operands are
3230 simple, it wins to evaluate the RHS unconditionally on machines
3231 with expensive branches. In this case, this isn't a comparison
3232 that can be merged. */
3234 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3235 are with zero (tmw). */
3237 if (BRANCH_COST >= 2
3238 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3239 && simple_operand_p (rl_arg)
3240 && simple_operand_p (rr_arg))
3241 return build (code, truth_type, lhs, rhs);
3243 /* See if the comparisons can be merged. Then get all the parameters for
3246 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3247 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3251 ll_inner = decode_field_reference (ll_arg,
3252 &ll_bitsize, &ll_bitpos, &ll_mode,
3253 &ll_unsignedp, &volatilep, &ll_mask,
3255 lr_inner = decode_field_reference (lr_arg,
3256 &lr_bitsize, &lr_bitpos, &lr_mode,
3257 &lr_unsignedp, &volatilep, &lr_mask,
3259 rl_inner = decode_field_reference (rl_arg,
3260 &rl_bitsize, &rl_bitpos, &rl_mode,
3261 &rl_unsignedp, &volatilep, &rl_mask,
3263 rr_inner = decode_field_reference (rr_arg,
3264 &rr_bitsize, &rr_bitpos, &rr_mode,
3265 &rr_unsignedp, &volatilep, &rr_mask,
3268 /* It must be true that the inner operation on the lhs of each
3269 comparison must be the same if we are to be able to do anything.
3270 Then see if we have constants. If not, the same must be true for
3272 if (volatilep || ll_inner == 0 || rl_inner == 0
3273 || ! operand_equal_p (ll_inner, rl_inner, 0))
3276 if (TREE_CODE (lr_arg) == INTEGER_CST
3277 && TREE_CODE (rr_arg) == INTEGER_CST)
3278 l_const = lr_arg, r_const = rr_arg;
3279 else if (lr_inner == 0 || rr_inner == 0
3280 || ! operand_equal_p (lr_inner, rr_inner, 0))
3283 l_const = r_const = 0;
3285 /* If either comparison code is not correct for our logical operation,
3286 fail. However, we can convert a one-bit comparison against zero into
3287 the opposite comparison against that bit being set in the field. */
3289 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3290 if (lcode != wanted_code)
3292 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3298 if (rcode != wanted_code)
3300 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3306 /* See if we can find a mode that contains both fields being compared on
3307 the left. If we can't, fail. Otherwise, update all constants and masks
3308 to be relative to a field of that size. */
3309 first_bit = MIN (ll_bitpos, rl_bitpos);
3310 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3311 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3312 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3314 if (lnmode == VOIDmode)
3317 lnbitsize = GET_MODE_BITSIZE (lnmode);
3318 lnbitpos = first_bit & ~ (lnbitsize - 1);
3319 type = type_for_size (lnbitsize, 1);
3320 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3322 if (BYTES_BIG_ENDIAN)
3324 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3325 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3328 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3329 size_int (xll_bitpos), 0);
3330 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3331 size_int (xrl_bitpos), 0);
3335 l_const = convert (type, l_const);
3336 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3337 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3338 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3339 fold (build1 (BIT_NOT_EXPR,
3343 warning ("comparison is always %s",
3344 wanted_code == NE_EXPR ? "one" : "zero");
3346 return convert (truth_type,
3347 wanted_code == NE_EXPR
3348 ? integer_one_node : integer_zero_node);
3353 r_const = convert (type, r_const);
3354 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3355 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3356 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3357 fold (build1 (BIT_NOT_EXPR,
3361 warning ("comparison is always %s",
3362 wanted_code == NE_EXPR ? "one" : "zero");
3364 return convert (truth_type,
3365 wanted_code == NE_EXPR
3366 ? integer_one_node : integer_zero_node);
3370 /* If the right sides are not constant, do the same for it. Also,
3371 disallow this optimization if a size or signedness mismatch occurs
3372 between the left and right sides. */
3375 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3376 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3377 /* Make sure the two fields on the right
3378 correspond to the left without being swapped. */
3379 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3382 first_bit = MIN (lr_bitpos, rr_bitpos);
3383 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3384 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3385 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3387 if (rnmode == VOIDmode)
3390 rnbitsize = GET_MODE_BITSIZE (rnmode);
3391 rnbitpos = first_bit & ~ (rnbitsize - 1);
3392 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3394 if (BYTES_BIG_ENDIAN)
3396 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3397 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3400 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3401 size_int (xlr_bitpos), 0);
3402 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3403 size_int (xrr_bitpos), 0);
3405 /* Make a mask that corresponds to both fields being compared.
3406 Do this for both items being compared. If the masks agree,
3407 we can do this by masking both and comparing the masked
3409 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3410 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3411 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3413 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3414 ll_unsignedp || rl_unsignedp);
3415 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3416 lr_unsignedp || rr_unsignedp);
3417 if (! all_ones_mask_p (ll_mask, lnbitsize))
3419 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3420 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3422 return build (wanted_code, truth_type, lhs, rhs);
3425 /* There is still another way we can do something: If both pairs of
3426 fields being compared are adjacent, we may be able to make a wider
3427 field containing them both. */
3428 if ((ll_bitsize + ll_bitpos == rl_bitpos
3429 && lr_bitsize + lr_bitpos == rr_bitpos)
3430 || (ll_bitpos == rl_bitpos + rl_bitsize
3431 && lr_bitpos == rr_bitpos + rr_bitsize))
3432 return build (wanted_code, truth_type,
3433 make_bit_field_ref (ll_inner, type,
3434 ll_bitsize + rl_bitsize,
3435 MIN (ll_bitpos, rl_bitpos),
3437 make_bit_field_ref (lr_inner, type,
3438 lr_bitsize + rr_bitsize,
3439 MIN (lr_bitpos, rr_bitpos),
3445 /* Handle the case of comparisons with constants. If there is something in
3446 common between the masks, those bits of the constants must be the same.
3447 If not, the condition is always false. Test for this to avoid generating
3448 incorrect code below. */
3449 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3450 if (! integer_zerop (result)
3451 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3452 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3454 if (wanted_code == NE_EXPR)
3456 warning ("`or' of unmatched not-equal tests is always 1");
3457 return convert (truth_type, integer_one_node);
3461 warning ("`and' of mutually exclusive equal-tests is always zero");
3462 return convert (truth_type, integer_zero_node);
3466 /* Construct the expression we will return. First get the component
3467 reference we will make. Unless the mask is all ones the width of
3468 that field, perform the mask operation. Then compare with the
3470 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3471 ll_unsignedp || rl_unsignedp);
3473 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3474 if (! all_ones_mask_p (ll_mask, lnbitsize))
3475 result = build (BIT_AND_EXPR, type, result, ll_mask);
3477 return build (wanted_code, truth_type, result,
3478 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3481 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3482 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3483 that we may sometimes modify the tree. */
3486 strip_compound_expr (t, s)
3490 tree type = TREE_TYPE (t);
3491 enum tree_code code = TREE_CODE (t);
3493 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3494 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3495 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3496 return TREE_OPERAND (t, 1);
3498 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3499 don't bother handling any other types. */
3500 else if (code == COND_EXPR)
3502 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3503 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3504 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3506 else if (TREE_CODE_CLASS (code) == '1')
3507 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3508 else if (TREE_CODE_CLASS (code) == '<'
3509 || TREE_CODE_CLASS (code) == '2')
3511 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3512 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3518 /* Perform constant folding and related simplification of EXPR.
3519 The related simplifications include x*1 => x, x*0 => 0, etc.,
3520 and application of the associative law.
3521 NOP_EXPR conversions may be removed freely (as long as we
3522 are careful not to change the C type of the overall expression)
3523 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3524 but we can constant-fold them if they have constant operands. */
3530 register tree t = expr;
3531 tree t1 = NULL_TREE;
3533 tree type = TREE_TYPE (expr);
3534 register tree arg0, arg1;
3535 register enum tree_code code = TREE_CODE (t);
3539 /* WINS will be nonzero when the switch is done
3540 if all operands are constant. */
3544 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3545 Likewise for a SAVE_EXPR that's already been evaluated. */
3546 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3549 /* Return right away if already constant. */
3550 if (TREE_CONSTANT (t))
3552 if (code == CONST_DECL)
3553 return DECL_INITIAL (t);
3557 kind = TREE_CODE_CLASS (code);
3558 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3562 /* Special case for conversion ops that can have fixed point args. */
3563 arg0 = TREE_OPERAND (t, 0);
3565 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3567 STRIP_TYPE_NOPS (arg0);
3569 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3570 subop = TREE_REALPART (arg0);
3574 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3575 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3576 && TREE_CODE (subop) != REAL_CST
3577 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3579 /* Note that TREE_CONSTANT isn't enough:
3580 static var addresses are constant but we can't
3581 do arithmetic on them. */
3584 else if (kind == 'e' || kind == '<'
3585 || kind == '1' || kind == '2' || kind == 'r')
3587 register int len = tree_code_length[(int) code];
3589 for (i = 0; i < len; i++)
3591 tree op = TREE_OPERAND (t, i);
3595 continue; /* Valid for CALL_EXPR, at least. */
3597 if (kind == '<' || code == RSHIFT_EXPR)
3599 /* Signedness matters here. Perhaps we can refine this
3601 STRIP_TYPE_NOPS (op);
3605 /* Strip any conversions that don't change the mode. */
3609 if (TREE_CODE (op) == COMPLEX_CST)
3610 subop = TREE_REALPART (op);
3614 if (TREE_CODE (subop) != INTEGER_CST
3615 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3616 && TREE_CODE (subop) != REAL_CST
3617 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3619 /* Note that TREE_CONSTANT isn't enough:
3620 static var addresses are constant but we can't
3621 do arithmetic on them. */
3631 /* If this is a commutative operation, and ARG0 is a constant, move it
3632 to ARG1 to reduce the number of tests below. */
3633 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3634 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3635 || code == BIT_AND_EXPR)
3636 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3638 tem = arg0; arg0 = arg1; arg1 = tem;
3640 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3641 TREE_OPERAND (t, 1) = tem;
3644 /* Now WINS is set as described above,
3645 ARG0 is the first operand of EXPR,
3646 and ARG1 is the second operand (if it has more than one operand).
3648 First check for cases where an arithmetic operation is applied to a
3649 compound, conditional, or comparison operation. Push the arithmetic
3650 operation inside the compound or conditional to see if any folding
3651 can then be done. Convert comparison to conditional for this purpose.
3652 The also optimizes non-constant cases that used to be done in
3655 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3656 one of the operands is a comparison and the other is a comparison, a
3657 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3658 code below would make the expression more complex. Change it to a
3659 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3660 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3662 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3663 || code == EQ_EXPR || code == NE_EXPR)
3664 && ((truth_value_p (TREE_CODE (arg0))
3665 && (truth_value_p (TREE_CODE (arg1))
3666 || (TREE_CODE (arg1) == BIT_AND_EXPR
3667 && integer_onep (TREE_OPERAND (arg1, 1)))))
3668 || (truth_value_p (TREE_CODE (arg1))
3669 && (truth_value_p (TREE_CODE (arg0))
3670 || (TREE_CODE (arg0) == BIT_AND_EXPR
3671 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3673 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3674 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3678 if (code == EQ_EXPR)
3679 t = invert_truthvalue (t);
3684 if (TREE_CODE_CLASS (code) == '1')
3686 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3687 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3688 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3689 else if (TREE_CODE (arg0) == COND_EXPR)
3691 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3692 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3693 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3695 /* If this was a conversion, and all we did was to move into
3696 inside the COND_EXPR, bring it back out. But leave it if
3697 it is a conversion from integer to integer and the
3698 result precision is no wider than a word since such a
3699 conversion is cheap and may be optimized away by combine,
3700 while it couldn't if it were outside the COND_EXPR. Then return
3701 so we don't get into an infinite recursion loop taking the
3702 conversion out and then back in. */
3704 if ((code == NOP_EXPR || code == CONVERT_EXPR
3705 || code == NON_LVALUE_EXPR)
3706 && TREE_CODE (t) == COND_EXPR
3707 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3708 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3709 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3710 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3711 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3712 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3713 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3714 t = build1 (code, type,
3716 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3717 TREE_OPERAND (t, 0),
3718 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3719 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3722 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3723 return fold (build (COND_EXPR, type, arg0,
3724 fold (build1 (code, type, integer_one_node)),
3725 fold (build1 (code, type, integer_zero_node))));
3727 else if (TREE_CODE_CLASS (code) == '2'
3728 || TREE_CODE_CLASS (code) == '<')
3730 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3731 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3732 fold (build (code, type,
3733 arg0, TREE_OPERAND (arg1, 1))));
3734 else if (TREE_CODE (arg1) == COND_EXPR
3735 || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<')
3737 tree test, true_value, false_value;
3739 if (TREE_CODE (arg1) == COND_EXPR)
3741 test = TREE_OPERAND (arg1, 0);
3742 true_value = TREE_OPERAND (arg1, 1);
3743 false_value = TREE_OPERAND (arg1, 2);
3747 tree testtype = TREE_TYPE (arg1);
3749 true_value = convert (testtype, integer_one_node);
3750 false_value = convert (testtype, integer_zero_node);
3753 /* If ARG0 is complex we want to make sure we only evaluate
3754 it once. Though this is only required if it is volatile, it
3755 might be more efficient even if it is not. However, if we
3756 succeed in folding one part to a constant, we do not need
3757 to make this SAVE_EXPR. Since we do this optimization
3758 primarily to see if we do end up with constant and this
3759 SAVE_EXPR interferes with later optimizations, suppressing
3760 it when we can is important. */
3762 if (TREE_CODE (arg0) != SAVE_EXPR
3763 && ((TREE_CODE (arg0) != VAR_DECL
3764 && TREE_CODE (arg0) != PARM_DECL)
3765 || TREE_SIDE_EFFECTS (arg0)))
3767 tree lhs = fold (build (code, type, arg0, true_value));
3768 tree rhs = fold (build (code, type, arg0, false_value));
3770 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3771 return fold (build (COND_EXPR, type, test, lhs, rhs));
3773 arg0 = save_expr (arg0);
3776 test = fold (build (COND_EXPR, type, test,
3777 fold (build (code, type, arg0, true_value)),
3778 fold (build (code, type, arg0, false_value))));
3779 if (TREE_CODE (arg0) == SAVE_EXPR)
3780 return build (COMPOUND_EXPR, type,
3781 convert (void_type_node, arg0),
3782 strip_compound_expr (test, arg0));
3784 return convert (type, test);
3787 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3788 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3789 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3790 else if (TREE_CODE (arg0) == COND_EXPR
3791 || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3793 tree test, true_value, false_value;
3795 if (TREE_CODE (arg0) == COND_EXPR)
3797 test = TREE_OPERAND (arg0, 0);
3798 true_value = TREE_OPERAND (arg0, 1);
3799 false_value = TREE_OPERAND (arg0, 2);
3803 tree testtype = TREE_TYPE (arg0);
3805 true_value = convert (testtype, integer_one_node);
3806 false_value = convert (testtype, integer_zero_node);
3809 if (TREE_CODE (arg1) != SAVE_EXPR
3810 && ((TREE_CODE (arg1) != VAR_DECL
3811 && TREE_CODE (arg1) != PARM_DECL)
3812 || TREE_SIDE_EFFECTS (arg1)))
3814 tree lhs = fold (build (code, type, true_value, arg1));
3815 tree rhs = fold (build (code, type, false_value, arg1));
3817 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
3818 || TREE_CONSTANT (arg1))
3819 return fold (build (COND_EXPR, type, test, lhs, rhs));
3821 arg1 = save_expr (arg1);
3824 test = fold (build (COND_EXPR, type, test,
3825 fold (build (code, type, true_value, arg1)),
3826 fold (build (code, type, false_value, arg1))));
3827 if (TREE_CODE (arg1) == SAVE_EXPR)
3828 return build (COMPOUND_EXPR, type,
3829 convert (void_type_node, arg1),
3830 strip_compound_expr (test, arg1));
3832 return convert (type, test);
3835 else if (TREE_CODE_CLASS (code) == '<'
3836 && TREE_CODE (arg0) == COMPOUND_EXPR)
3837 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3838 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3839 else if (TREE_CODE_CLASS (code) == '<'
3840 && TREE_CODE (arg1) == COMPOUND_EXPR)
3841 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3842 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3854 return fold (DECL_INITIAL (t));
3859 case FIX_TRUNC_EXPR:
3860 /* Other kinds of FIX are not handled properly by fold_convert. */
3862 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
3863 return TREE_OPERAND (t, 0);
3865 /* Handle cases of two conversions in a row. */
3866 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
3867 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
3869 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3870 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
3871 tree final_type = TREE_TYPE (t);
3872 int inside_int = INTEGRAL_TYPE_P (inside_type);
3873 int inside_ptr = POINTER_TYPE_P (inside_type);
3874 int inside_float = FLOAT_TYPE_P (inside_type);
3875 int inside_prec = TYPE_PRECISION (inside_type);
3876 int inside_unsignedp = TREE_UNSIGNED (inside_type);
3877 int inter_int = INTEGRAL_TYPE_P (inter_type);
3878 int inter_ptr = POINTER_TYPE_P (inter_type);
3879 int inter_float = FLOAT_TYPE_P (inter_type);
3880 int inter_prec = TYPE_PRECISION (inter_type);
3881 int inter_unsignedp = TREE_UNSIGNED (inter_type);
3882 int final_int = INTEGRAL_TYPE_P (final_type);
3883 int final_ptr = POINTER_TYPE_P (final_type);
3884 int final_float = FLOAT_TYPE_P (final_type);
3885 int final_prec = TYPE_PRECISION (final_type);
3886 int final_unsignedp = TREE_UNSIGNED (final_type);
3888 /* In addition to the cases of two conversions in a row
3889 handled below, if we are converting something to its own
3890 type via an object of identical or wider precision, neither
3891 conversion is needed. */
3892 if (inside_type == final_type
3893 && ((inter_int && final_int) || (inter_float && final_float))
3894 && inter_prec >= final_prec)
3895 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
3897 /* Likewise, if the intermediate and final types are either both
3898 float or both integer, we don't need the middle conversion if
3899 it is wider than the final type and doesn't change the signedness
3900 (for integers). Avoid this if the final type is a pointer
3901 since then we sometimes need the inner conversion. Likewise if
3902 the outer has a precision not equal to the size of its mode. */
3903 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
3904 || (inter_float && inside_float))
3905 && inter_prec >= inside_prec
3906 && (inter_float || inter_unsignedp == inside_unsignedp)
3907 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
3908 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
3910 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3912 /* Two conversions in a row are not needed unless:
3913 - some conversion is floating-point (overstrict for now), or
3914 - the intermediate type is narrower than both initial and
3916 - the intermediate type and innermost type differ in signedness,
3917 and the outermost type is wider than the intermediate, or
3918 - the initial type is a pointer type and the precisions of the
3919 intermediate and final types differ, or
3920 - the final type is a pointer type and the precisions of the
3921 initial and intermediate types differ. */
3922 if (! inside_float && ! inter_float && ! final_float
3923 && (inter_prec > inside_prec || inter_prec > final_prec)
3924 && ! (inside_int && inter_int
3925 && inter_unsignedp != inside_unsignedp
3926 && inter_prec < final_prec)
3927 && ((inter_unsignedp && inter_prec > inside_prec)
3928 == (final_unsignedp && final_prec > inter_prec))
3929 && ! (inside_ptr && inter_prec != final_prec)
3930 && ! (final_ptr && inside_prec != inter_prec)
3931 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
3932 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
3934 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3937 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
3938 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
3939 /* Detect assigning a bitfield. */
3940 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
3941 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
3943 /* Don't leave an assignment inside a conversion
3944 unless assigning a bitfield. */
3945 tree prev = TREE_OPERAND (t, 0);
3946 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
3947 /* First do the assignment, then return converted constant. */
3948 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
3954 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
3957 return fold_convert (t, arg0);
3959 #if 0 /* This loses on &"foo"[0]. */
3964 /* Fold an expression like: "foo"[2] */
3965 if (TREE_CODE (arg0) == STRING_CST
3966 && TREE_CODE (arg1) == INTEGER_CST
3967 && !TREE_INT_CST_HIGH (arg1)
3968 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
3970 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
3971 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
3972 force_fit_type (t, 0);
3979 if (TREE_CODE (arg0) == CONSTRUCTOR)
3981 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
3988 TREE_CONSTANT (t) = wins;
3994 if (TREE_CODE (arg0) == INTEGER_CST)
3996 HOST_WIDE_INT low, high;
3997 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
3998 TREE_INT_CST_HIGH (arg0),
4000 t = build_int_2 (low, high);
4001 TREE_TYPE (t) = type;
4003 = (TREE_OVERFLOW (arg0)
4004 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4005 TREE_CONSTANT_OVERFLOW (t)
4006 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4008 else if (TREE_CODE (arg0) == REAL_CST)
4009 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4010 TREE_TYPE (t) = type;
4012 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4013 return TREE_OPERAND (arg0, 0);
4015 /* Convert - (a - b) to (b - a) for non-floating-point. */
4016 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4017 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4018 TREE_OPERAND (arg0, 0));
4025 if (TREE_CODE (arg0) == INTEGER_CST)
4027 if (! TREE_UNSIGNED (type)
4028 && TREE_INT_CST_HIGH (arg0) < 0)
4030 HOST_WIDE_INT low, high;
4031 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4032 TREE_INT_CST_HIGH (arg0),
4034 t = build_int_2 (low, high);
4035 TREE_TYPE (t) = type;
4037 = (TREE_OVERFLOW (arg0)
4038 | force_fit_type (t, overflow));
4039 TREE_CONSTANT_OVERFLOW (t)
4040 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4043 else if (TREE_CODE (arg0) == REAL_CST)
4045 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4046 t = build_real (type,
4047 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4049 TREE_TYPE (t) = type;
4051 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4052 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4056 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4058 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4059 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4060 TREE_OPERAND (arg0, 0),
4061 fold (build1 (NEGATE_EXPR,
4062 TREE_TYPE (TREE_TYPE (arg0)),
4063 TREE_OPERAND (arg0, 1))));
4064 else if (TREE_CODE (arg0) == COMPLEX_CST)
4065 return build_complex (type, TREE_OPERAND (arg0, 0),
4066 fold (build1 (NEGATE_EXPR,
4067 TREE_TYPE (TREE_TYPE (arg0)),
4068 TREE_OPERAND (arg0, 1))));
4069 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4070 return fold (build (TREE_CODE (arg0), type,
4071 fold (build1 (CONJ_EXPR, type,
4072 TREE_OPERAND (arg0, 0))),
4073 fold (build1 (CONJ_EXPR,
4074 type, TREE_OPERAND (arg0, 1)))));
4075 else if (TREE_CODE (arg0) == CONJ_EXPR)
4076 return TREE_OPERAND (arg0, 0);
4082 if (TREE_CODE (arg0) == INTEGER_CST)
4083 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4084 ~ TREE_INT_CST_HIGH (arg0));
4085 TREE_TYPE (t) = type;
4086 force_fit_type (t, 0);
4087 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4088 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4090 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4091 return TREE_OPERAND (arg0, 0);
4095 /* A + (-B) -> A - B */
4096 if (TREE_CODE (arg1) == NEGATE_EXPR)
4097 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4098 else if (! FLOAT_TYPE_P (type))
4100 if (integer_zerop (arg1))
4101 return non_lvalue (convert (type, arg0));
4103 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4104 with a constant, and the two constants have no bits in common,
4105 we should treat this as a BIT_IOR_EXPR since this may produce more
4107 if (TREE_CODE (arg0) == BIT_AND_EXPR
4108 && TREE_CODE (arg1) == BIT_AND_EXPR
4109 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4110 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4111 && integer_zerop (const_binop (BIT_AND_EXPR,
4112 TREE_OPERAND (arg0, 1),
4113 TREE_OPERAND (arg1, 1), 0)))
4115 code = BIT_IOR_EXPR;
4119 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4120 about the case where C is a constant, just try one of the
4121 four possibilities. */
4123 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4124 && operand_equal_p (TREE_OPERAND (arg0, 1),
4125 TREE_OPERAND (arg1, 1), 0))
4126 return fold (build (MULT_EXPR, type,
4127 fold (build (PLUS_EXPR, type,
4128 TREE_OPERAND (arg0, 0),
4129 TREE_OPERAND (arg1, 0))),
4130 TREE_OPERAND (arg0, 1)));
4132 /* In IEEE floating point, x+0 may not equal x. */
4133 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4135 && real_zerop (arg1))
4136 return non_lvalue (convert (type, arg0));
4138 /* In most languages, can't associate operations on floats
4139 through parentheses. Rather than remember where the parentheses
4140 were, we don't associate floats at all. It shouldn't matter much.
4141 However, associating multiplications is only very slightly
4142 inaccurate, so do that if -ffast-math is specified. */
4143 if (FLOAT_TYPE_P (type)
4144 && ! (flag_fast_math && code == MULT_EXPR))
4147 /* The varsign == -1 cases happen only for addition and subtraction.
4148 It says that the arg that was split was really CON minus VAR.
4149 The rest of the code applies to all associative operations. */
4155 if (split_tree (arg0, code, &var, &con, &varsign))
4159 /* EXPR is (CON-VAR) +- ARG1. */
4160 /* If it is + and VAR==ARG1, return just CONST. */
4161 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4162 return convert (TREE_TYPE (t), con);
4164 /* If ARG0 is a constant, don't change things around;
4165 instead keep all the constant computations together. */
4167 if (TREE_CONSTANT (arg0))
4170 /* Otherwise return (CON +- ARG1) - VAR. */
4171 t = build (MINUS_EXPR, type,
4172 fold (build (code, type, con, arg1)), var);
4176 /* EXPR is (VAR+CON) +- ARG1. */
4177 /* If it is - and VAR==ARG1, return just CONST. */
4178 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4179 return convert (TREE_TYPE (t), con);
4181 /* If ARG0 is a constant, don't change things around;
4182 instead keep all the constant computations together. */
4184 if (TREE_CONSTANT (arg0))
4187 /* Otherwise return VAR +- (ARG1 +- CON). */
4188 tem = fold (build (code, type, arg1, con));
4189 t = build (code, type, var, tem);
4191 if (integer_zerop (tem)
4192 && (code == PLUS_EXPR || code == MINUS_EXPR))
4193 return convert (type, var);
4194 /* If we have x +/- (c - d) [c an explicit integer]
4195 change it to x -/+ (d - c) since if d is relocatable
4196 then the latter can be a single immediate insn
4197 and the former cannot. */
4198 if (TREE_CODE (tem) == MINUS_EXPR
4199 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4201 tree tem1 = TREE_OPERAND (tem, 1);
4202 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4203 TREE_OPERAND (tem, 0) = tem1;
4205 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4211 if (split_tree (arg1, code, &var, &con, &varsign))
4213 if (TREE_CONSTANT (arg1))
4218 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4220 /* EXPR is ARG0 +- (CON +- VAR). */
4221 if (TREE_CODE (t) == MINUS_EXPR
4222 && operand_equal_p (var, arg0, 0))
4224 /* If VAR and ARG0 cancel, return just CON or -CON. */
4225 if (code == PLUS_EXPR)
4226 return convert (TREE_TYPE (t), con);
4227 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4228 convert (TREE_TYPE (t), con)));
4231 t = build (TREE_CODE (t), type,
4232 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4234 if (integer_zerop (TREE_OPERAND (t, 0))
4235 && TREE_CODE (t) == PLUS_EXPR)
4236 return convert (TREE_TYPE (t), var);
4241 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4242 if (TREE_CODE (arg1) == REAL_CST)
4244 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4246 t1 = const_binop (code, arg0, arg1, 0);
4247 if (t1 != NULL_TREE)
4249 /* The return value should always have
4250 the same type as the original expression. */
4251 TREE_TYPE (t1) = TREE_TYPE (t);
4257 if (! FLOAT_TYPE_P (type))
4259 if (! wins && integer_zerop (arg0))
4260 return build1 (NEGATE_EXPR, type, arg1);
4261 if (integer_zerop (arg1))
4262 return non_lvalue (convert (type, arg0));
4264 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4265 about the case where C is a constant, just try one of the
4266 four possibilities. */
4268 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4269 && operand_equal_p (TREE_OPERAND (arg0, 1),
4270 TREE_OPERAND (arg1, 1), 0))
4271 return fold (build (MULT_EXPR, type,
4272 fold (build (MINUS_EXPR, type,
4273 TREE_OPERAND (arg0, 0),
4274 TREE_OPERAND (arg1, 0))),
4275 TREE_OPERAND (arg0, 1)));
4277 /* Convert A - (-B) to A + B. */
4278 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4279 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4281 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4284 /* Except with IEEE floating point, 0-x equals -x. */
4285 if (! wins && real_zerop (arg0))
4286 return build1 (NEGATE_EXPR, type, arg1);
4287 /* Except with IEEE floating point, x-0 equals x. */
4288 if (real_zerop (arg1))
4289 return non_lvalue (convert (type, arg0));
4292 /* Fold &x - &x. This can happen from &x.foo - &x.
4293 This is unsafe for certain floats even in non-IEEE formats.
4294 In IEEE, it is unsafe because it does wrong for NaNs.
4295 Also note that operand_equal_p is always false if an operand
4298 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4299 && operand_equal_p (arg0, arg1, 0))
4300 return convert (type, integer_zero_node);
4305 if (! FLOAT_TYPE_P (type))
4307 if (integer_zerop (arg1))
4308 return omit_one_operand (type, arg1, arg0);
4309 if (integer_onep (arg1))
4310 return non_lvalue (convert (type, arg0));
4312 /* ((A / C) * C) is A if the division is an
4313 EXACT_DIV_EXPR. Since C is normally a constant,
4314 just check for one of the four possibilities. */
4316 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4317 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4318 return TREE_OPERAND (arg0, 0);
4320 /* (a * (1 << b)) is (a << b) */
4321 if (TREE_CODE (arg1) == LSHIFT_EXPR
4322 && integer_onep (TREE_OPERAND (arg1, 0)))
4323 return fold (build (LSHIFT_EXPR, type, arg0,
4324 TREE_OPERAND (arg1, 1)));
4325 if (TREE_CODE (arg0) == LSHIFT_EXPR
4326 && integer_onep (TREE_OPERAND (arg0, 0)))
4327 return fold (build (LSHIFT_EXPR, type, arg1,
4328 TREE_OPERAND (arg0, 1)));
4332 /* x*0 is 0, except for IEEE floating point. */
4333 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4335 && real_zerop (arg1))
4336 return omit_one_operand (type, arg1, arg0);
4337 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4338 However, ANSI says we can drop signals,
4339 so we can do this anyway. */
4340 if (real_onep (arg1))
4341 return non_lvalue (convert (type, arg0));
4343 if (! wins && real_twop (arg1))
4345 tree arg = save_expr (arg0);
4346 return build (PLUS_EXPR, type, arg, arg);
4354 register enum tree_code code0, code1;
4356 if (integer_all_onesp (arg1))
4357 return omit_one_operand (type, arg1, arg0);
4358 if (integer_zerop (arg1))
4359 return non_lvalue (convert (type, arg0));
4360 t1 = distribute_bit_expr (code, type, arg0, arg1);
4361 if (t1 != NULL_TREE)
4364 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4365 is a rotate of A by C1 bits. */
4366 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4367 is a rotate of A by B bits. */
4369 code0 = TREE_CODE (arg0);
4370 code1 = TREE_CODE (arg1);
4371 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4372 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4373 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4374 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4376 register tree tree01, tree11;
4377 register enum tree_code code01, code11;
4379 tree01 = TREE_OPERAND (arg0, 1);
4380 tree11 = TREE_OPERAND (arg1, 1);
4381 code01 = TREE_CODE (tree01);
4382 code11 = TREE_CODE (tree11);
4383 if (code01 == INTEGER_CST
4384 && code11 == INTEGER_CST
4385 && TREE_INT_CST_HIGH (tree01) == 0
4386 && TREE_INT_CST_HIGH (tree11) == 0
4387 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4388 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4389 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4390 code0 == LSHIFT_EXPR ? tree01 : tree11);
4391 else if (code11 == MINUS_EXPR
4392 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4393 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4394 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4395 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4396 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4397 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4398 type, TREE_OPERAND (arg0, 0), tree01);
4399 else if (code01 == MINUS_EXPR
4400 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4401 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4402 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4403 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4404 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4405 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4406 type, TREE_OPERAND (arg0, 0), tree11);
4413 if (integer_zerop (arg1))
4414 return non_lvalue (convert (type, arg0));
4415 if (integer_all_onesp (arg1))
4416 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4421 if (integer_all_onesp (arg1))
4422 return non_lvalue (convert (type, arg0));
4423 if (integer_zerop (arg1))
4424 return omit_one_operand (type, arg1, arg0);
4425 t1 = distribute_bit_expr (code, type, arg0, arg1);
4426 if (t1 != NULL_TREE)
4428 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4429 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4430 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4432 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4433 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4434 && (~TREE_INT_CST_LOW (arg0)
4435 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4436 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4438 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4439 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4441 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4442 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4443 && (~TREE_INT_CST_LOW (arg1)
4444 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4445 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4449 case BIT_ANDTC_EXPR:
4450 if (integer_all_onesp (arg0))
4451 return non_lvalue (convert (type, arg1));
4452 if (integer_zerop (arg0))
4453 return omit_one_operand (type, arg0, arg1);
4454 if (TREE_CODE (arg1) == INTEGER_CST)
4456 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4457 code = BIT_AND_EXPR;
4463 /* In most cases, do nothing with a divide by zero. */
4464 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4465 #ifndef REAL_INFINITY
4466 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4469 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4471 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4472 However, ANSI says we can drop signals, so we can do this anyway. */
4473 if (real_onep (arg1))
4474 return non_lvalue (convert (type, arg0));
4476 /* If ARG1 is a constant, we can convert this to a multiply by the
4477 reciprocal. This does not have the same rounding properties,
4478 so only do this if -ffast-math. We can actually always safely
4479 do it if ARG1 is a power of two, but it's hard to tell if it is
4480 or not in a portable manner. */
4481 if (TREE_CODE (arg1) == REAL_CST)
4484 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4486 return fold (build (MULT_EXPR, type, arg0, tem));
4487 /* Find the reciprocal if optimizing and the result is exact. */
4491 r = TREE_REAL_CST (arg1);
4492 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4494 tem = build_real (type, r);
4495 return fold (build (MULT_EXPR, type, arg0, tem));
4501 case TRUNC_DIV_EXPR:
4502 case ROUND_DIV_EXPR:
4503 case FLOOR_DIV_EXPR:
4505 case EXACT_DIV_EXPR:
4506 if (integer_onep (arg1))
4507 return non_lvalue (convert (type, arg0));
4508 if (integer_zerop (arg1))
4511 /* If we have ((a / C1) / C2) where both division are the same type, try
4512 to simplify. First see if C1 * C2 overflows or not. */
4513 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4514 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4518 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4519 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4521 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4522 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4524 /* If no overflow, divide by C1*C2. */
4525 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4529 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4530 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4531 expressions, which often appear in the offsets or sizes of
4532 objects with a varying size. Only deal with positive divisors
4533 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4535 Look for NOPs and SAVE_EXPRs inside. */
4537 if (TREE_CODE (arg1) == INTEGER_CST
4538 && tree_int_cst_sgn (arg1) >= 0)
4540 int have_save_expr = 0;
4541 tree c2 = integer_zero_node;
4544 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4545 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4549 if (TREE_CODE (xarg0) == PLUS_EXPR
4550 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4551 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4552 else if (TREE_CODE (xarg0) == MINUS_EXPR
4553 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4554 /* If we are doing this computation unsigned, the negate
4556 && ! TREE_UNSIGNED (type))
4558 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4559 xarg0 = TREE_OPERAND (xarg0, 0);
4562 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4563 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4567 if (TREE_CODE (xarg0) == MULT_EXPR
4568 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4569 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4570 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4571 TREE_OPERAND (xarg0, 1), arg1, 1))
4572 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4573 TREE_OPERAND (xarg0, 1), 1)))
4574 && (tree_int_cst_sgn (c2) >= 0
4575 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4578 tree outer_div = integer_one_node;
4579 tree c1 = TREE_OPERAND (xarg0, 1);
4582 /* If C3 > C1, set them equal and do a divide by
4583 C3/C1 at the end of the operation. */
4584 if (tree_int_cst_lt (c1, c3))
4585 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4587 /* The result is A * (C1/C3) + (C2/C3). */
4588 t = fold (build (PLUS_EXPR, type,
4589 fold (build (MULT_EXPR, type,
4590 TREE_OPERAND (xarg0, 0),
4591 const_binop (code, c1, c3, 1))),
4592 const_binop (code, c2, c3, 1)));
4594 if (! integer_onep (outer_div))
4595 t = fold (build (code, type, t, convert (type, outer_div)));
4607 case FLOOR_MOD_EXPR:
4608 case ROUND_MOD_EXPR:
4609 case TRUNC_MOD_EXPR:
4610 if (integer_onep (arg1))
4611 return omit_one_operand (type, integer_zero_node, arg0);
4612 if (integer_zerop (arg1))
4615 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4616 where C1 % C3 == 0. Handle similarly to the division case,
4617 but don't bother with SAVE_EXPRs. */
4619 if (TREE_CODE (arg1) == INTEGER_CST
4620 && ! integer_zerop (arg1))
4622 tree c2 = integer_zero_node;
4625 if (TREE_CODE (xarg0) == PLUS_EXPR
4626 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4627 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4628 else if (TREE_CODE (xarg0) == MINUS_EXPR
4629 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4630 && ! TREE_UNSIGNED (type))
4632 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4633 xarg0 = TREE_OPERAND (xarg0, 0);
4638 if (TREE_CODE (xarg0) == MULT_EXPR
4639 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4640 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4641 TREE_OPERAND (xarg0, 1),
4643 && tree_int_cst_sgn (c2) >= 0)
4644 /* The result is (C2%C3). */
4645 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4646 TREE_OPERAND (xarg0, 0));
4655 if (integer_zerop (arg1))
4656 return non_lvalue (convert (type, arg0));
4657 /* Since negative shift count is not well-defined,
4658 don't try to compute it in the compiler. */
4659 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4661 /* Rewrite an LROTATE_EXPR by a constant into an
4662 RROTATE_EXPR by a new constant. */
4663 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4665 TREE_SET_CODE (t, RROTATE_EXPR);
4666 code = RROTATE_EXPR;
4667 TREE_OPERAND (t, 1) = arg1
4670 convert (TREE_TYPE (arg1),
4671 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4673 if (tree_int_cst_sgn (arg1) < 0)
4677 /* If we have a rotate of a bit operation with the rotate count and
4678 the second operand of the bit operation both constant,
4679 permute the two operations. */
4680 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4681 && (TREE_CODE (arg0) == BIT_AND_EXPR
4682 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4683 || TREE_CODE (arg0) == BIT_IOR_EXPR
4684 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4685 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4686 return fold (build (TREE_CODE (arg0), type,
4687 fold (build (code, type,
4688 TREE_OPERAND (arg0, 0), arg1)),
4689 fold (build (code, type,
4690 TREE_OPERAND (arg0, 1), arg1))));
4692 /* Two consecutive rotates adding up to the width of the mode can
4694 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4695 && TREE_CODE (arg0) == RROTATE_EXPR
4696 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4697 && TREE_INT_CST_HIGH (arg1) == 0
4698 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4699 && ((TREE_INT_CST_LOW (arg1)
4700 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4701 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4702 return TREE_OPERAND (arg0, 0);
4707 if (operand_equal_p (arg0, arg1, 0))
4709 if (INTEGRAL_TYPE_P (type)
4710 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4711 return omit_one_operand (type, arg1, arg0);
4715 if (operand_equal_p (arg0, arg1, 0))
4717 if (INTEGRAL_TYPE_P (type)
4718 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4719 return omit_one_operand (type, arg1, arg0);
4722 case TRUTH_NOT_EXPR:
4723 /* Note that the operand of this must be an int
4724 and its values must be 0 or 1.
4725 ("true" is a fixed value perhaps depending on the language,
4726 but we don't handle values other than 1 correctly yet.) */
4727 tem = invert_truthvalue (arg0);
4728 /* Avoid infinite recursion. */
4729 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4731 return convert (type, tem);
4733 case TRUTH_ANDIF_EXPR:
4734 /* Note that the operands of this must be ints
4735 and their values must be 0 or 1.
4736 ("true" is a fixed value perhaps depending on the language.) */
4737 /* If first arg is constant zero, return it. */
4738 if (integer_zerop (arg0))
4740 case TRUTH_AND_EXPR:
4741 /* If either arg is constant true, drop it. */
4742 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4743 return non_lvalue (arg1);
4744 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4745 return non_lvalue (arg0);
4746 /* If second arg is constant zero, result is zero, but first arg
4747 must be evaluated. */
4748 if (integer_zerop (arg1))
4749 return omit_one_operand (type, arg1, arg0);
4750 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4751 case will be handled here. */
4752 if (integer_zerop (arg0))
4753 return omit_one_operand (type, arg0, arg1);
4756 /* We only do these simplifications if we are optimizing. */
4760 /* Check for things like (A || B) && (A || C). We can convert this
4761 to A || (B && C). Note that either operator can be any of the four
4762 truth and/or operations and the transformation will still be
4763 valid. Also note that we only care about order for the
4764 ANDIF and ORIF operators. */
4765 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4766 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4767 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4768 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4769 || TREE_CODE (arg0) == TRUTH_OR_EXPR))
4771 tree a00 = TREE_OPERAND (arg0, 0);
4772 tree a01 = TREE_OPERAND (arg0, 1);
4773 tree a10 = TREE_OPERAND (arg1, 0);
4774 tree a11 = TREE_OPERAND (arg1, 1);
4775 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
4776 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
4777 && (code == TRUTH_AND_EXPR
4778 || code == TRUTH_OR_EXPR));
4780 if (operand_equal_p (a00, a10, 0))
4781 return fold (build (TREE_CODE (arg0), type, a00,
4782 fold (build (code, type, a01, a11))));
4783 else if (commutative && operand_equal_p (a00, a11, 0))
4784 return fold (build (TREE_CODE (arg0), type, a00,
4785 fold (build (code, type, a01, a10))));
4786 else if (commutative && operand_equal_p (a01, a10, 0))
4787 return fold (build (TREE_CODE (arg0), type, a01,
4788 fold (build (code, type, a00, a11))));
4790 /* This case if tricky because we must either have commutative
4791 operators or else A10 must not have side-effects. */
4793 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
4794 && operand_equal_p (a01, a11, 0))
4795 return fold (build (TREE_CODE (arg0), type,
4796 fold (build (code, type, a00, a10)),
4800 /* See if we can build a range comparison. */
4801 if (0 != (tem = fold_range_test (t)))
4804 /* Check for the possibility of merging component references. If our
4805 lhs is another similar operation, try to merge its rhs with our
4806 rhs. Then try to merge our lhs and rhs. */
4807 if (TREE_CODE (arg0) == code
4808 && 0 != (tem = fold_truthop (code, type,
4809 TREE_OPERAND (arg0, 1), arg1)))
4810 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
4812 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
4817 case TRUTH_ORIF_EXPR:
4818 /* Note that the operands of this must be ints
4819 and their values must be 0 or true.
4820 ("true" is a fixed value perhaps depending on the language.) */
4821 /* If first arg is constant true, return it. */
4822 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4825 /* If either arg is constant zero, drop it. */
4826 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
4827 return non_lvalue (arg1);
4828 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
4829 return non_lvalue (arg0);
4830 /* If second arg is constant true, result is true, but we must
4831 evaluate first arg. */
4832 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4833 return omit_one_operand (type, arg1, arg0);
4834 /* Likewise for first arg, but note this only occurs here for
4836 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4837 return omit_one_operand (type, arg0, arg1);
4840 case TRUTH_XOR_EXPR:
4841 /* If either arg is constant zero, drop it. */
4842 if (integer_zerop (arg0))
4843 return non_lvalue (arg1);
4844 if (integer_zerop (arg1))
4845 return non_lvalue (arg0);
4846 /* If either arg is constant true, this is a logical inversion. */
4847 if (integer_onep (arg0))
4848 return non_lvalue (invert_truthvalue (arg1));
4849 if (integer_onep (arg1))
4850 return non_lvalue (invert_truthvalue (arg0));
4859 /* If one arg is a constant integer, put it last. */
4860 if (TREE_CODE (arg0) == INTEGER_CST
4861 && TREE_CODE (arg1) != INTEGER_CST)
4863 TREE_OPERAND (t, 0) = arg1;
4864 TREE_OPERAND (t, 1) = arg0;
4865 arg0 = TREE_OPERAND (t, 0);
4866 arg1 = TREE_OPERAND (t, 1);
4867 code = swap_tree_comparison (code);
4868 TREE_SET_CODE (t, code);
4871 /* Convert foo++ == CONST into ++foo == CONST + INCR.
4872 First, see if one arg is constant; find the constant arg
4873 and the other one. */
4875 tree constop = 0, varop;
4876 int constopnum = -1;
4878 if (TREE_CONSTANT (arg1))
4879 constopnum = 1, constop = arg1, varop = arg0;
4880 if (TREE_CONSTANT (arg0))
4881 constopnum = 0, constop = arg0, varop = arg1;
4883 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
4885 /* This optimization is invalid for ordered comparisons
4886 if CONST+INCR overflows or if foo+incr might overflow.
4887 This optimization is invalid for floating point due to rounding.
4888 For pointer types we assume overflow doesn't happen. */
4889 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4890 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4891 && (code == EQ_EXPR || code == NE_EXPR)))
4894 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
4895 constop, TREE_OPERAND (varop, 1)));
4896 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
4898 /* If VAROP is a reference to a bitfield, we must mask
4899 the constant by the width of the field. */
4900 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
4901 && DECL_BIT_FIELD(TREE_OPERAND
4902 (TREE_OPERAND (varop, 0), 1)))
4905 = TREE_INT_CST_LOW (DECL_SIZE
4907 (TREE_OPERAND (varop, 0), 1)));
4909 newconst = fold (build (BIT_AND_EXPR,
4910 TREE_TYPE (varop), newconst,
4911 convert (TREE_TYPE (varop),
4912 build_int_2 (size, 0))));
4916 t = build (code, type, TREE_OPERAND (t, 0),
4917 TREE_OPERAND (t, 1));
4918 TREE_OPERAND (t, constopnum) = newconst;
4922 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
4924 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4925 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4926 && (code == EQ_EXPR || code == NE_EXPR)))
4929 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
4930 constop, TREE_OPERAND (varop, 1)));
4931 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
4933 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
4934 && DECL_BIT_FIELD(TREE_OPERAND
4935 (TREE_OPERAND (varop, 0), 1)))
4938 = TREE_INT_CST_LOW (DECL_SIZE
4940 (TREE_OPERAND (varop, 0), 1)));
4942 newconst = fold (build (BIT_AND_EXPR,
4943 TREE_TYPE (varop), newconst,
4944 convert (TREE_TYPE (varop),
4945 build_int_2 (size, 0))));
4949 t = build (code, type, TREE_OPERAND (t, 0),
4950 TREE_OPERAND (t, 1));
4951 TREE_OPERAND (t, constopnum) = newconst;
4957 /* Change X >= CST to X > (CST - 1) if CST is positive. */
4958 if (TREE_CODE (arg1) == INTEGER_CST
4959 && TREE_CODE (arg0) != INTEGER_CST
4960 && tree_int_cst_sgn (arg1) > 0)
4962 switch (TREE_CODE (t))
4966 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4967 t = build (code, type, TREE_OPERAND (t, 0), arg1);
4972 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4973 t = build (code, type, TREE_OPERAND (t, 0), arg1);
4978 /* If this is an EQ or NE comparison with zero and ARG0 is
4979 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
4980 two operations, but the latter can be done in one less insn
4981 one machine that have only two-operand insns or on which a
4982 constant cannot be the first operand. */
4983 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
4984 && TREE_CODE (arg0) == BIT_AND_EXPR)
4986 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
4987 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
4989 fold (build (code, type,
4990 build (BIT_AND_EXPR, TREE_TYPE (arg0),
4992 TREE_TYPE (TREE_OPERAND (arg0, 0)),
4993 TREE_OPERAND (arg0, 1),
4994 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
4995 convert (TREE_TYPE (arg0),
4998 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
4999 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5001 fold (build (code, type,
5002 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5004 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5005 TREE_OPERAND (arg0, 0),
5006 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5007 convert (TREE_TYPE (arg0),
5012 /* If this is an NE or EQ comparison of zero against the result of a
5013 signed MOD operation whose second operand is a power of 2, make
5014 the MOD operation unsigned since it is simpler and equivalent. */
5015 if ((code == NE_EXPR || code == EQ_EXPR)
5016 && integer_zerop (arg1)
5017 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5018 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5019 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5020 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5021 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5022 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5024 tree newtype = unsigned_type (TREE_TYPE (arg0));
5025 tree newmod = build (TREE_CODE (arg0), newtype,
5026 convert (newtype, TREE_OPERAND (arg0, 0)),
5027 convert (newtype, TREE_OPERAND (arg0, 1)));
5029 return build (code, type, newmod, convert (newtype, arg1));
5032 /* If this is an NE comparison of zero with an AND of one, remove the
5033 comparison since the AND will give the correct value. */
5034 if (code == NE_EXPR && integer_zerop (arg1)
5035 && TREE_CODE (arg0) == BIT_AND_EXPR
5036 && integer_onep (TREE_OPERAND (arg0, 1)))
5037 return convert (type, arg0);
5039 /* If we have (A & C) == C where C is a power of 2, convert this into
5040 (A & C) != 0. Similarly for NE_EXPR. */
5041 if ((code == EQ_EXPR || code == NE_EXPR)
5042 && TREE_CODE (arg0) == BIT_AND_EXPR
5043 && integer_pow2p (TREE_OPERAND (arg0, 1))
5044 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5045 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5046 arg0, integer_zero_node);
5048 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5049 and similarly for >= into !=. */
5050 if ((code == LT_EXPR || code == GE_EXPR)
5051 && TREE_UNSIGNED (TREE_TYPE (arg0))
5052 && TREE_CODE (arg1) == LSHIFT_EXPR
5053 && integer_onep (TREE_OPERAND (arg1, 0)))
5054 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5055 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5056 TREE_OPERAND (arg1, 1)),
5057 convert (TREE_TYPE (arg0), integer_zero_node));
5059 else if ((code == LT_EXPR || code == GE_EXPR)
5060 && TREE_UNSIGNED (TREE_TYPE (arg0))
5061 && (TREE_CODE (arg1) == NOP_EXPR
5062 || TREE_CODE (arg1) == CONVERT_EXPR)
5063 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5064 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5066 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5067 convert (TREE_TYPE (arg0),
5068 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5069 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5070 convert (TREE_TYPE (arg0), integer_zero_node));
5072 /* Simplify comparison of something with itself. (For IEEE
5073 floating-point, we can only do some of these simplifications.) */
5074 if (operand_equal_p (arg0, arg1, 0))
5081 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5083 t = build_int_2 (1, 0);
5084 TREE_TYPE (t) = type;
5088 TREE_SET_CODE (t, code);
5092 /* For NE, we can only do this simplification if integer. */
5093 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5095 /* ... fall through ... */
5098 t = build_int_2 (0, 0);
5099 TREE_TYPE (t) = type;
5104 /* An unsigned comparison against 0 can be simplified. */
5105 if (integer_zerop (arg1)
5106 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5107 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5108 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5110 switch (TREE_CODE (t))
5114 TREE_SET_CODE (t, NE_EXPR);
5118 TREE_SET_CODE (t, EQ_EXPR);
5121 return omit_one_operand (type,
5122 convert (type, integer_one_node),
5125 return omit_one_operand (type,
5126 convert (type, integer_zero_node),
5131 /* If we are comparing an expression that just has comparisons
5132 of two integer values, arithmetic expressions of those comparisons,
5133 and constants, we can simplify it. There are only three cases
5134 to check: the two values can either be equal, the first can be
5135 greater, or the second can be greater. Fold the expression for
5136 those three values. Since each value must be 0 or 1, we have
5137 eight possibilities, each of which corresponds to the constant 0
5138 or 1 or one of the six possible comparisons.
5140 This handles common cases like (a > b) == 0 but also handles
5141 expressions like ((x > y) - (y > x)) > 0, which supposedly
5142 occur in macroized code. */
5144 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5146 tree cval1 = 0, cval2 = 0;
5149 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5150 /* Don't handle degenerate cases here; they should already
5151 have been handled anyway. */
5152 && cval1 != 0 && cval2 != 0
5153 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5154 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5155 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5156 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5157 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5159 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5160 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5162 /* We can't just pass T to eval_subst in case cval1 or cval2
5163 was the same as ARG1. */
5166 = fold (build (code, type,
5167 eval_subst (arg0, cval1, maxval, cval2, minval),
5170 = fold (build (code, type,
5171 eval_subst (arg0, cval1, maxval, cval2, maxval),
5174 = fold (build (code, type,
5175 eval_subst (arg0, cval1, minval, cval2, maxval),
5178 /* All three of these results should be 0 or 1. Confirm they
5179 are. Then use those values to select the proper code
5182 if ((integer_zerop (high_result)
5183 || integer_onep (high_result))
5184 && (integer_zerop (equal_result)
5185 || integer_onep (equal_result))
5186 && (integer_zerop (low_result)
5187 || integer_onep (low_result)))
5189 /* Make a 3-bit mask with the high-order bit being the
5190 value for `>', the next for '=', and the low for '<'. */
5191 switch ((integer_onep (high_result) * 4)
5192 + (integer_onep (equal_result) * 2)
5193 + integer_onep (low_result))
5197 return omit_one_operand (type, integer_zero_node, arg0);
5218 return omit_one_operand (type, integer_one_node, arg0);
5221 t = build (code, type, cval1, cval2);
5223 return save_expr (t);
5230 /* If this is a comparison of a field, we may be able to simplify it. */
5231 if ((TREE_CODE (arg0) == COMPONENT_REF
5232 || TREE_CODE (arg0) == BIT_FIELD_REF)
5233 && (code == EQ_EXPR || code == NE_EXPR)
5234 /* Handle the constant case even without -O
5235 to make sure the warnings are given. */
5236 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5238 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5242 /* If this is a comparison of complex values and either or both
5243 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5244 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5245 may prevent needless evaluations. */
5246 if ((code == EQ_EXPR || code == NE_EXPR)
5247 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5248 && (TREE_CODE (arg0) == COMPLEX_EXPR
5249 || TREE_CODE (arg1) == COMPLEX_EXPR))
5251 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5252 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5253 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5254 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5255 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5257 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5260 fold (build (code, type, real0, real1)),
5261 fold (build (code, type, imag0, imag1))));
5264 /* From here on, the only cases we handle are when the result is
5265 known to be a constant.
5267 To compute GT, swap the arguments and do LT.
5268 To compute GE, do LT and invert the result.
5269 To compute LE, swap the arguments, do LT and invert the result.
5270 To compute NE, do EQ and invert the result.
5272 Therefore, the code below must handle only EQ and LT. */
5274 if (code == LE_EXPR || code == GT_EXPR)
5276 tem = arg0, arg0 = arg1, arg1 = tem;
5277 code = swap_tree_comparison (code);
5280 /* Note that it is safe to invert for real values here because we
5281 will check below in the one case that it matters. */
5284 if (code == NE_EXPR || code == GE_EXPR)
5287 code = invert_tree_comparison (code);
5290 /* Compute a result for LT or EQ if args permit;
5291 otherwise return T. */
5292 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5294 if (code == EQ_EXPR)
5295 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5296 == TREE_INT_CST_LOW (arg1))
5297 && (TREE_INT_CST_HIGH (arg0)
5298 == TREE_INT_CST_HIGH (arg1)),
5301 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5302 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5303 : INT_CST_LT (arg0, arg1)),
5307 /* Assume a nonexplicit constant cannot equal an explicit one,
5308 since such code would be undefined anyway.
5309 Exception: on sysvr4, using #pragma weak,
5310 a label can come out as 0. */
5311 else if (TREE_CODE (arg1) == INTEGER_CST
5312 && !integer_zerop (arg1)
5313 && TREE_CONSTANT (arg0)
5314 && TREE_CODE (arg0) == ADDR_EXPR
5316 t1 = build_int_2 (0, 0);
5318 /* Two real constants can be compared explicitly. */
5319 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5321 /* If either operand is a NaN, the result is false with two
5322 exceptions: First, an NE_EXPR is true on NaNs, but that case
5323 is already handled correctly since we will be inverting the
5324 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5325 or a GE_EXPR into a LT_EXPR, we must return true so that it
5326 will be inverted into false. */
5328 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5329 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5330 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5332 else if (code == EQ_EXPR)
5333 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5334 TREE_REAL_CST (arg1)),
5337 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5338 TREE_REAL_CST (arg1)),
5342 if (t1 == NULL_TREE)
5346 TREE_INT_CST_LOW (t1) ^= 1;
5348 TREE_TYPE (t1) = type;
5352 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5353 so all simple results must be passed through pedantic_non_lvalue. */
5354 if (TREE_CODE (arg0) == INTEGER_CST)
5355 return pedantic_non_lvalue
5356 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5357 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5358 return pedantic_omit_one_operand (type, arg1, arg0);
5360 /* If the second operand is zero, invert the comparison and swap
5361 the second and third operands. Likewise if the second operand
5362 is constant and the third is not or if the third operand is
5363 equivalent to the first operand of the comparison. */
5365 if (integer_zerop (arg1)
5366 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5367 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5368 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5369 TREE_OPERAND (t, 2),
5370 TREE_OPERAND (arg0, 1))))
5372 /* See if this can be inverted. If it can't, possibly because
5373 it was a floating-point inequality comparison, don't do
5375 tem = invert_truthvalue (arg0);
5377 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5379 t = build (code, type, tem,
5380 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5382 arg1 = TREE_OPERAND (t, 2);
5387 /* If we have A op B ? A : C, we may be able to convert this to a
5388 simpler expression, depending on the operation and the values
5389 of B and C. IEEE floating point prevents this though,
5390 because A or B might be -0.0 or a NaN. */
5392 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5393 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5394 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5396 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5397 arg1, TREE_OPERAND (arg0, 1)))
5399 tree arg2 = TREE_OPERAND (t, 2);
5400 enum tree_code comp_code = TREE_CODE (arg0);
5404 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5405 depending on the comparison operation. */
5406 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5407 ? real_zerop (TREE_OPERAND (arg0, 1))
5408 : integer_zerop (TREE_OPERAND (arg0, 1)))
5409 && TREE_CODE (arg2) == NEGATE_EXPR
5410 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5414 return pedantic_non_lvalue
5415 (fold (build1 (NEGATE_EXPR, type, arg1)));
5417 return pedantic_non_lvalue (convert (type, arg1));
5420 return pedantic_non_lvalue
5421 (convert (type, fold (build1 (ABS_EXPR,
5422 TREE_TYPE (arg1), arg1))));
5425 return pedantic_non_lvalue
5426 (fold (build1 (NEGATE_EXPR, type,
5428 fold (build1 (ABS_EXPR,
5433 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5436 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5438 if (comp_code == NE_EXPR)
5439 return pedantic_non_lvalue (convert (type, arg1));
5440 else if (comp_code == EQ_EXPR)
5441 return pedantic_non_lvalue (convert (type, integer_zero_node));
5444 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5445 or max (A, B), depending on the operation. */
5447 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5448 arg2, TREE_OPERAND (arg0, 0)))
5450 tree comp_op0 = TREE_OPERAND (arg0, 0);
5451 tree comp_op1 = TREE_OPERAND (arg0, 1);
5452 tree comp_type = TREE_TYPE (comp_op0);
5457 return pedantic_non_lvalue (convert (type, arg2));
5459 return pedantic_non_lvalue (convert (type, arg1));
5462 return pedantic_non_lvalue
5463 (convert (type, (fold (build (MIN_EXPR, comp_type,
5464 comp_op0, comp_op1)))));
5467 return pedantic_non_lvalue
5468 (convert (type, fold (build (MAX_EXPR, comp_type,
5469 comp_op0, comp_op1))));
5473 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5474 we might still be able to simplify this. For example,
5475 if C1 is one less or one more than C2, this might have started
5476 out as a MIN or MAX and been transformed by this function.
5477 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5479 if (INTEGRAL_TYPE_P (type)
5480 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5481 && TREE_CODE (arg2) == INTEGER_CST)
5485 /* We can replace A with C1 in this case. */
5486 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5487 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5488 TREE_OPERAND (t, 2));
5492 /* If C1 is C2 + 1, this is min(A, C2). */
5493 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5494 && operand_equal_p (TREE_OPERAND (arg0, 1),
5495 const_binop (PLUS_EXPR, arg2,
5496 integer_one_node, 0), 1))
5497 return pedantic_non_lvalue
5498 (fold (build (MIN_EXPR, type, arg1, arg2)));
5502 /* If C1 is C2 - 1, this is min(A, C2). */
5503 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5504 && operand_equal_p (TREE_OPERAND (arg0, 1),
5505 const_binop (MINUS_EXPR, arg2,
5506 integer_one_node, 0), 1))
5507 return pedantic_non_lvalue
5508 (fold (build (MIN_EXPR, type, arg1, arg2)));
5512 /* If C1 is C2 - 1, this is max(A, C2). */
5513 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5514 && operand_equal_p (TREE_OPERAND (arg0, 1),
5515 const_binop (MINUS_EXPR, arg2,
5516 integer_one_node, 0), 1))
5517 return pedantic_non_lvalue
5518 (fold (build (MAX_EXPR, type, arg1, arg2)));
5522 /* If C1 is C2 + 1, this is max(A, C2). */
5523 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5524 && operand_equal_p (TREE_OPERAND (arg0, 1),
5525 const_binop (PLUS_EXPR, arg2,
5526 integer_one_node, 0), 1))
5527 return pedantic_non_lvalue
5528 (fold (build (MAX_EXPR, type, arg1, arg2)));
5533 /* If the second operand is simpler than the third, swap them
5534 since that produces better jump optimization results. */
5535 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5536 || TREE_CODE (arg1) == SAVE_EXPR)
5537 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5538 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5539 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5541 /* See if this can be inverted. If it can't, possibly because
5542 it was a floating-point inequality comparison, don't do
5544 tem = invert_truthvalue (arg0);
5546 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5548 t = build (code, type, tem,
5549 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5551 arg1 = TREE_OPERAND (t, 2);
5556 /* Convert A ? 1 : 0 to simply A. */
5557 if (integer_onep (TREE_OPERAND (t, 1))
5558 && integer_zerop (TREE_OPERAND (t, 2))
5559 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5560 call to fold will try to move the conversion inside
5561 a COND, which will recurse. In that case, the COND_EXPR
5562 is probably the best choice, so leave it alone. */
5563 && type == TREE_TYPE (arg0))
5564 return pedantic_non_lvalue (arg0);
5566 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5567 operation is simply A & 2. */
5569 if (integer_zerop (TREE_OPERAND (t, 2))
5570 && TREE_CODE (arg0) == NE_EXPR
5571 && integer_zerop (TREE_OPERAND (arg0, 1))
5572 && integer_pow2p (arg1)
5573 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5574 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5576 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5581 /* When pedantic, a compound expression can be neither an lvalue
5582 nor an integer constant expression. */
5583 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5585 /* Don't let (0, 0) be null pointer constant. */
5586 if (integer_zerop (arg1))
5587 return non_lvalue (arg1);
5592 return build_complex (type, arg0, arg1);
5596 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5598 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5599 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5600 TREE_OPERAND (arg0, 1));
5601 else if (TREE_CODE (arg0) == COMPLEX_CST)
5602 return TREE_REALPART (arg0);
5603 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5604 return fold (build (TREE_CODE (arg0), type,
5605 fold (build1 (REALPART_EXPR, type,
5606 TREE_OPERAND (arg0, 0))),
5607 fold (build1 (REALPART_EXPR,
5608 type, TREE_OPERAND (arg0, 1)))));
5612 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5613 return convert (type, integer_zero_node);
5614 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5615 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5616 TREE_OPERAND (arg0, 0));
5617 else if (TREE_CODE (arg0) == COMPLEX_CST)
5618 return TREE_IMAGPART (arg0);
5619 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5620 return fold (build (TREE_CODE (arg0), type,
5621 fold (build1 (IMAGPART_EXPR, type,
5622 TREE_OPERAND (arg0, 0))),
5623 fold (build1 (IMAGPART_EXPR, type,
5624 TREE_OPERAND (arg0, 1)))));
5627 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5629 case CLEANUP_POINT_EXPR:
5630 if (! TREE_SIDE_EFFECTS (arg0))
5631 return TREE_OPERAND (t, 0);
5634 enum tree_code code0 = TREE_CODE (arg0);
5635 int kind0 = TREE_CODE_CLASS (code0);
5636 tree arg00 = TREE_OPERAND (arg0, 0);
5639 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5640 return fold (build1 (code0, type,
5641 fold (build1 (CLEANUP_POINT_EXPR,
5642 TREE_TYPE (arg00), arg00))));
5644 if (kind0 == '<' || kind0 == '2'
5645 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5646 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5647 || code0 == TRUTH_XOR_EXPR)
5649 arg01 = TREE_OPERAND (arg0, 1);
5651 if (! TREE_SIDE_EFFECTS (arg00))
5652 return fold (build (code0, type, arg00,
5653 fold (build1 (CLEANUP_POINT_EXPR,
5654 TREE_TYPE (arg01), arg01))));
5656 if (! TREE_SIDE_EFFECTS (arg01))
5657 return fold (build (code0, type,
5658 fold (build1 (CLEANUP_POINT_EXPR,
5659 TREE_TYPE (arg00), arg00)),
5668 } /* switch (code) */