1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-96, 1997 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /*@@ This file should be rewritten to use an arbitrary precision
22 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
23 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
24 @@ The routines that translate from the ap rep should
25 @@ warn if precision et. al. is lost.
26 @@ This would also make life easier when this technology is used
27 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int 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));
1075 int no_overflow = 0;
1080 low = int1l | int2l, hi = int1h | int2h;
1084 low = int1l ^ int2l, hi = int1h ^ int2h;
1088 low = int1l & int2l, hi = int1h & int2h;
1091 case BIT_ANDTC_EXPR:
1092 low = int1l & ~int2l, hi = int1h & ~int2h;
1098 /* It's unclear from the C standard whether shifts can overflow.
1099 The following code ignores overflow; perhaps a C standard
1100 interpretation ruling is needed. */
1101 lshift_double (int1l, int1h, int2l,
1102 TYPE_PRECISION (TREE_TYPE (arg1)),
1111 lrotate_double (int1l, int1h, int2l,
1112 TYPE_PRECISION (TREE_TYPE (arg1)),
1117 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1121 neg_double (int2l, int2h, &low, &hi);
1122 add_double (int1l, int1h, low, hi, &low, &hi);
1123 overflow = overflow_sum_sign (hi, int2h, int1h);
1127 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1130 case TRUNC_DIV_EXPR:
1131 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1132 case EXACT_DIV_EXPR:
1133 /* This is a shortcut for a common special case. */
1134 if (int2h == 0 && int2l > 0
1135 && ! TREE_CONSTANT_OVERFLOW (arg1)
1136 && ! TREE_CONSTANT_OVERFLOW (arg2)
1137 && int1h == 0 && int1l >= 0)
1139 if (code == CEIL_DIV_EXPR)
1141 low = int1l / int2l, hi = 0;
1145 /* ... fall through ... */
1147 case ROUND_DIV_EXPR:
1148 if (int2h == 0 && int2l == 1)
1150 low = int1l, hi = int1h;
1153 if (int1l == int2l && int1h == int2h
1154 && ! (int1l == 0 && int1h == 0))
1159 overflow = div_and_round_double (code, uns,
1160 int1l, int1h, int2l, int2h,
1161 &low, &hi, &garbagel, &garbageh);
1164 case TRUNC_MOD_EXPR:
1165 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1166 /* This is a shortcut for a common special case. */
1167 if (int2h == 0 && int2l > 0
1168 && ! TREE_CONSTANT_OVERFLOW (arg1)
1169 && ! TREE_CONSTANT_OVERFLOW (arg2)
1170 && int1h == 0 && int1l >= 0)
1172 if (code == CEIL_MOD_EXPR)
1174 low = int1l % int2l, hi = 0;
1178 /* ... fall through ... */
1180 case ROUND_MOD_EXPR:
1181 overflow = div_and_round_double (code, uns,
1182 int1l, int1h, int2l, int2h,
1183 &garbagel, &garbageh, &low, &hi);
1190 low = (((unsigned HOST_WIDE_INT) int1h
1191 < (unsigned HOST_WIDE_INT) int2h)
1192 || (((unsigned HOST_WIDE_INT) int1h
1193 == (unsigned HOST_WIDE_INT) int2h)
1194 && ((unsigned HOST_WIDE_INT) int1l
1195 < (unsigned HOST_WIDE_INT) int2l)));
1199 low = ((int1h < int2h)
1200 || ((int1h == int2h)
1201 && ((unsigned HOST_WIDE_INT) int1l
1202 < (unsigned HOST_WIDE_INT) int2l)));
1204 if (low == (code == MIN_EXPR))
1205 low = int1l, hi = int1h;
1207 low = int2l, hi = int2h;
1214 if (TREE_TYPE (arg1) == sizetype && hi == 0
1215 && low >= 0 && low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype))
1217 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1221 t = build_int_2 (low, hi);
1222 TREE_TYPE (t) = TREE_TYPE (arg1);
1226 = ((notrunc ? !uns && overflow
1227 : force_fit_type (t, overflow && !uns) && ! no_overflow)
1228 | TREE_OVERFLOW (arg1)
1229 | TREE_OVERFLOW (arg2));
1230 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1231 | TREE_CONSTANT_OVERFLOW (arg1)
1232 | TREE_CONSTANT_OVERFLOW (arg2));
1235 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1236 if (TREE_CODE (arg1) == REAL_CST)
1241 REAL_VALUE_TYPE value;
1244 d1 = TREE_REAL_CST (arg1);
1245 d2 = TREE_REAL_CST (arg2);
1247 /* If either operand is a NaN, just return it. Otherwise, set up
1248 for floating-point trap; we return an overflow. */
1249 if (REAL_VALUE_ISNAN (d1))
1251 else if (REAL_VALUE_ISNAN (d2))
1253 else if (setjmp (float_error))
1255 t = copy_node (arg1);
1260 set_float_handler (float_error);
1262 #ifdef REAL_ARITHMETIC
1263 REAL_ARITHMETIC (value, code, d1, d2);
1280 #ifndef REAL_INFINITY
1289 value = MIN (d1, d2);
1293 value = MAX (d1, d2);
1299 #endif /* no REAL_ARITHMETIC */
1300 t = build_real (TREE_TYPE (arg1),
1301 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1303 set_float_handler (NULL_PTR);
1306 = (force_fit_type (t, overflow)
1307 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1308 TREE_CONSTANT_OVERFLOW (t)
1310 | TREE_CONSTANT_OVERFLOW (arg1)
1311 | TREE_CONSTANT_OVERFLOW (arg2);
1314 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1315 if (TREE_CODE (arg1) == COMPLEX_CST)
1317 register tree type = TREE_TYPE (arg1);
1318 register tree r1 = TREE_REALPART (arg1);
1319 register tree i1 = TREE_IMAGPART (arg1);
1320 register tree r2 = TREE_REALPART (arg2);
1321 register tree i2 = TREE_IMAGPART (arg2);
1327 t = build_complex (type,
1328 const_binop (PLUS_EXPR, r1, r2, notrunc),
1329 const_binop (PLUS_EXPR, i1, i2, notrunc));
1333 t = build_complex (type,
1334 const_binop (MINUS_EXPR, r1, r2, notrunc),
1335 const_binop (MINUS_EXPR, i1, i2, notrunc));
1339 t = build_complex (type,
1340 const_binop (MINUS_EXPR,
1341 const_binop (MULT_EXPR,
1343 const_binop (MULT_EXPR,
1346 const_binop (PLUS_EXPR,
1347 const_binop (MULT_EXPR,
1349 const_binop (MULT_EXPR,
1356 register tree magsquared
1357 = const_binop (PLUS_EXPR,
1358 const_binop (MULT_EXPR, r2, r2, notrunc),
1359 const_binop (MULT_EXPR, i2, i2, notrunc),
1362 t = build_complex (type,
1364 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1365 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1366 const_binop (PLUS_EXPR,
1367 const_binop (MULT_EXPR, r1, r2,
1369 const_binop (MULT_EXPR, i1, i2,
1372 magsquared, notrunc),
1374 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1375 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1376 const_binop (MINUS_EXPR,
1377 const_binop (MULT_EXPR, i1, r2,
1379 const_binop (MULT_EXPR, r1, i2,
1382 magsquared, notrunc));
1394 /* Return an INTEGER_CST with value V and type from `sizetype'. */
1398 unsigned HOST_WIDE_INT number;
1401 /* Type-size nodes already made for small sizes. */
1402 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1404 if (number < 2*HOST_BITS_PER_WIDE_INT + 1
1405 && size_table[number] != 0)
1406 return size_table[number];
1407 if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
1409 push_obstacks_nochange ();
1410 /* Make this a permanent node. */
1411 end_temporary_allocation ();
1412 t = build_int_2 (number, 0);
1413 TREE_TYPE (t) = sizetype;
1414 size_table[number] = t;
1419 t = build_int_2 (number, 0);
1420 TREE_TYPE (t) = sizetype;
1421 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1426 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1427 CODE is a tree code. Data type is taken from `sizetype',
1428 If the operands are constant, so is the result. */
1431 size_binop (code, arg0, arg1)
1432 enum tree_code code;
1435 /* Handle the special case of two integer constants faster. */
1436 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1438 /* And some specific cases even faster than that. */
1439 if (code == PLUS_EXPR && integer_zerop (arg0))
1441 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1442 && integer_zerop (arg1))
1444 else if (code == MULT_EXPR && integer_onep (arg0))
1447 /* Handle general case of two integer constants. */
1448 return const_binop (code, arg0, arg1, 0);
1451 if (arg0 == error_mark_node || arg1 == error_mark_node)
1452 return error_mark_node;
1454 return fold (build (code, sizetype, arg0, arg1));
1457 /* Given T, a tree representing type conversion of ARG1, a constant,
1458 return a constant tree representing the result of conversion. */
1461 fold_convert (t, arg1)
1465 register tree type = TREE_TYPE (t);
1468 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1470 if (TREE_CODE (arg1) == INTEGER_CST)
1472 /* If we would build a constant wider than GCC supports,
1473 leave the conversion unfolded. */
1474 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1477 /* Given an integer constant, make new constant with new type,
1478 appropriately sign-extended or truncated. */
1479 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1480 TREE_INT_CST_HIGH (arg1));
1481 TREE_TYPE (t) = type;
1482 /* Indicate an overflow if (1) ARG1 already overflowed,
1483 or (2) force_fit_type indicates an overflow.
1484 Tell force_fit_type that an overflow has already occurred
1485 if ARG1 is a too-large unsigned value and T is signed. */
1487 = (TREE_OVERFLOW (arg1)
1488 | force_fit_type (t,
1489 (TREE_INT_CST_HIGH (arg1) < 0
1490 & (TREE_UNSIGNED (type)
1491 < TREE_UNSIGNED (TREE_TYPE (arg1))))));
1492 TREE_CONSTANT_OVERFLOW (t)
1493 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1495 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1496 else if (TREE_CODE (arg1) == REAL_CST)
1498 /* Don't initialize these, use assignments.
1499 Initialized local aggregates don't work on old compilers. */
1503 tree type1 = TREE_TYPE (arg1);
1505 x = TREE_REAL_CST (arg1);
1506 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1507 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1508 /* See if X will be in range after truncation towards 0.
1509 To compensate for truncation, move the bounds away from 0,
1510 but reject if X exactly equals the adjusted bounds. */
1511 #ifdef REAL_ARITHMETIC
1512 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1513 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1518 /* If X is a NaN, use zero instead and show we have an overflow.
1519 Otherwise, range check. */
1520 if (REAL_VALUE_ISNAN (x))
1521 overflow = 1, x = dconst0;
1522 else if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
1525 #ifndef REAL_ARITHMETIC
1527 HOST_WIDE_INT low, high;
1528 HOST_WIDE_INT half_word
1529 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1534 high = (HOST_WIDE_INT) (x / half_word / half_word);
1535 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1536 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1538 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1539 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1542 low = (HOST_WIDE_INT) x;
1543 if (TREE_REAL_CST (arg1) < 0)
1544 neg_double (low, high, &low, &high);
1545 t = build_int_2 (low, high);
1549 HOST_WIDE_INT low, high;
1550 REAL_VALUE_TO_INT (&low, &high, x);
1551 t = build_int_2 (low, high);
1554 TREE_TYPE (t) = type;
1556 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1557 TREE_CONSTANT_OVERFLOW (t)
1558 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1560 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1561 TREE_TYPE (t) = type;
1563 else if (TREE_CODE (type) == REAL_TYPE)
1565 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1566 if (TREE_CODE (arg1) == INTEGER_CST)
1567 return build_real_from_int_cst (type, arg1);
1568 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1569 if (TREE_CODE (arg1) == REAL_CST)
1571 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1574 TREE_TYPE (arg1) = type;
1577 else if (setjmp (float_error))
1580 t = copy_node (arg1);
1583 set_float_handler (float_error);
1585 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1586 TREE_REAL_CST (arg1)));
1587 set_float_handler (NULL_PTR);
1591 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1592 TREE_CONSTANT_OVERFLOW (t)
1593 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1597 TREE_CONSTANT (t) = 1;
1601 /* Return an expr equal to X but certainly not valid as an lvalue.
1602 Also make sure it is not valid as an null pointer constant. */
1610 /* These things are certainly not lvalues. */
1611 if (TREE_CODE (x) == NON_LVALUE_EXPR
1612 || TREE_CODE (x) == INTEGER_CST
1613 || TREE_CODE (x) == REAL_CST
1614 || TREE_CODE (x) == STRING_CST
1615 || TREE_CODE (x) == ADDR_EXPR)
1617 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1619 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1620 so convert_for_assignment won't strip it.
1621 This is so this 0 won't be treated as a null pointer constant. */
1622 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1623 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1629 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1630 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1634 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1635 Zero means allow extended lvalues. */
1637 int pedantic_lvalues;
1639 /* When pedantic, return an expr equal to X but certainly not valid as a
1640 pedantic lvalue. Otherwise, return X. */
1643 pedantic_non_lvalue (x)
1646 if (pedantic_lvalues)
1647 return non_lvalue (x);
1652 /* Given a tree comparison code, return the code that is the logical inverse
1653 of the given code. It is not safe to do this for floating-point
1654 comparisons, except for NE_EXPR and EQ_EXPR. */
1656 static enum tree_code
1657 invert_tree_comparison (code)
1658 enum tree_code code;
1679 /* Similar, but return the comparison that results if the operands are
1680 swapped. This is safe for floating-point. */
1682 static enum tree_code
1683 swap_tree_comparison (code)
1684 enum tree_code code;
1704 /* Return nonzero if CODE is a tree code that represents a truth value. */
1707 truth_value_p (code)
1708 enum tree_code code;
1710 return (TREE_CODE_CLASS (code) == '<'
1711 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1712 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1713 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1716 /* Return nonzero if two operands are necessarily equal.
1717 If ONLY_CONST is non-zero, only return non-zero for constants.
1718 This function tests whether the operands are indistinguishable;
1719 it does not test whether they are equal using C's == operation.
1720 The distinction is important for IEEE floating point, because
1721 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1722 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1725 operand_equal_p (arg0, arg1, only_const)
1729 /* If both types don't have the same signedness, then we can't consider
1730 them equal. We must check this before the STRIP_NOPS calls
1731 because they may change the signedness of the arguments. */
1732 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1738 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1739 /* This is needed for conversions and for COMPONENT_REF.
1740 Might as well play it safe and always test this. */
1741 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1744 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1745 We don't care about side effects in that case because the SAVE_EXPR
1746 takes care of that for us. In all other cases, two expressions are
1747 equal if they have no side effects. If we have two identical
1748 expressions with side effects that should be treated the same due
1749 to the only side effects being identical SAVE_EXPR's, that will
1750 be detected in the recursive calls below. */
1751 if (arg0 == arg1 && ! only_const
1752 && (TREE_CODE (arg0) == SAVE_EXPR
1753 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1756 /* Next handle constant cases, those for which we can return 1 even
1757 if ONLY_CONST is set. */
1758 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1759 switch (TREE_CODE (arg0))
1762 return (TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1763 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
1766 return REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), TREE_REAL_CST (arg1));
1769 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1771 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1775 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1776 && ! strncmp (TREE_STRING_POINTER (arg0),
1777 TREE_STRING_POINTER (arg1),
1778 TREE_STRING_LENGTH (arg0)));
1781 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1788 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1791 /* Two conversions are equal only if signedness and modes match. */
1792 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1793 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1794 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1797 return operand_equal_p (TREE_OPERAND (arg0, 0),
1798 TREE_OPERAND (arg1, 0), 0);
1802 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1803 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1807 /* For commutative ops, allow the other order. */
1808 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1809 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1810 || TREE_CODE (arg0) == BIT_IOR_EXPR
1811 || TREE_CODE (arg0) == BIT_XOR_EXPR
1812 || TREE_CODE (arg0) == BIT_AND_EXPR
1813 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1814 && operand_equal_p (TREE_OPERAND (arg0, 0),
1815 TREE_OPERAND (arg1, 1), 0)
1816 && operand_equal_p (TREE_OPERAND (arg0, 1),
1817 TREE_OPERAND (arg1, 0), 0));
1820 switch (TREE_CODE (arg0))
1823 return operand_equal_p (TREE_OPERAND (arg0, 0),
1824 TREE_OPERAND (arg1, 0), 0);
1828 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1829 TREE_OPERAND (arg1, 0), 0)
1830 && operand_equal_p (TREE_OPERAND (arg0, 1),
1831 TREE_OPERAND (arg1, 1), 0));
1834 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1835 TREE_OPERAND (arg1, 0), 0)
1836 && operand_equal_p (TREE_OPERAND (arg0, 1),
1837 TREE_OPERAND (arg1, 1), 0)
1838 && operand_equal_p (TREE_OPERAND (arg0, 2),
1839 TREE_OPERAND (arg1, 2), 0));
1847 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1848 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1850 When in doubt, return 0. */
1853 operand_equal_for_comparison_p (arg0, arg1, other)
1857 int unsignedp1, unsignedpo;
1858 tree primarg1, primother;
1859 unsigned correct_width;
1861 if (operand_equal_p (arg0, arg1, 0))
1864 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1865 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1868 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1869 actual comparison operand, ARG0.
1871 First throw away any conversions to wider types
1872 already present in the operands. */
1874 primarg1 = get_narrower (arg1, &unsignedp1);
1875 primother = get_narrower (other, &unsignedpo);
1877 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1878 if (unsignedp1 == unsignedpo
1879 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1880 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1882 tree type = TREE_TYPE (arg0);
1884 /* Make sure shorter operand is extended the right way
1885 to match the longer operand. */
1886 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1887 TREE_TYPE (primarg1)),
1890 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1897 /* See if ARG is an expression that is either a comparison or is performing
1898 arithmetic on comparisons. The comparisons must only be comparing
1899 two different values, which will be stored in *CVAL1 and *CVAL2; if
1900 they are non-zero it means that some operands have already been found.
1901 No variables may be used anywhere else in the expression except in the
1902 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1903 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1905 If this is true, return 1. Otherwise, return zero. */
1908 twoval_comparison_p (arg, cval1, cval2, save_p)
1910 tree *cval1, *cval2;
1913 enum tree_code code = TREE_CODE (arg);
1914 char class = TREE_CODE_CLASS (code);
1916 /* We can handle some of the 'e' cases here. */
1917 if (class == 'e' && code == TRUTH_NOT_EXPR)
1919 else if (class == 'e'
1920 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1921 || code == COMPOUND_EXPR))
1924 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1925 the expression. There may be no way to make this work, but it needs
1926 to be looked at again for 2.6. */
1928 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1930 /* If we've already found a CVAL1 or CVAL2, this expression is
1931 two complex to handle. */
1932 if (*cval1 || *cval2)
1943 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
1946 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
1947 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1948 cval1, cval2, save_p));
1954 if (code == COND_EXPR)
1955 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
1956 cval1, cval2, save_p)
1957 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1958 cval1, cval2, save_p)
1959 && twoval_comparison_p (TREE_OPERAND (arg, 2),
1960 cval1, cval2, save_p));
1964 /* First see if we can handle the first operand, then the second. For
1965 the second operand, we know *CVAL1 can't be zero. It must be that
1966 one side of the comparison is each of the values; test for the
1967 case where this isn't true by failing if the two operands
1970 if (operand_equal_p (TREE_OPERAND (arg, 0),
1971 TREE_OPERAND (arg, 1), 0))
1975 *cval1 = TREE_OPERAND (arg, 0);
1976 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
1978 else if (*cval2 == 0)
1979 *cval2 = TREE_OPERAND (arg, 0);
1980 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
1985 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
1987 else if (*cval2 == 0)
1988 *cval2 = TREE_OPERAND (arg, 1);
1989 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2000 /* ARG is a tree that is known to contain just arithmetic operations and
2001 comparisons. Evaluate the operations in the tree substituting NEW0 for
2002 any occurrence of OLD0 as an operand of a comparison and likewise for
2006 eval_subst (arg, old0, new0, old1, new1)
2008 tree old0, new0, old1, new1;
2010 tree type = TREE_TYPE (arg);
2011 enum tree_code code = TREE_CODE (arg);
2012 char class = TREE_CODE_CLASS (code);
2014 /* We can handle some of the 'e' cases here. */
2015 if (class == 'e' && code == TRUTH_NOT_EXPR)
2017 else if (class == 'e'
2018 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2024 return fold (build1 (code, type,
2025 eval_subst (TREE_OPERAND (arg, 0),
2026 old0, new0, old1, new1)));
2029 return fold (build (code, type,
2030 eval_subst (TREE_OPERAND (arg, 0),
2031 old0, new0, old1, new1),
2032 eval_subst (TREE_OPERAND (arg, 1),
2033 old0, new0, old1, new1)));
2039 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2042 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2045 return fold (build (code, type,
2046 eval_subst (TREE_OPERAND (arg, 0),
2047 old0, new0, old1, new1),
2048 eval_subst (TREE_OPERAND (arg, 1),
2049 old0, new0, old1, new1),
2050 eval_subst (TREE_OPERAND (arg, 2),
2051 old0, new0, old1, new1)));
2056 tree arg0 = TREE_OPERAND (arg, 0);
2057 tree arg1 = TREE_OPERAND (arg, 1);
2059 /* We need to check both for exact equality and tree equality. The
2060 former will be true if the operand has a side-effect. In that
2061 case, we know the operand occurred exactly once. */
2063 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2065 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2068 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2070 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2073 return fold (build (code, type, arg0, arg1));
2080 /* Return a tree for the case when the result of an expression is RESULT
2081 converted to TYPE and OMITTED was previously an operand of the expression
2082 but is now not needed (e.g., we folded OMITTED * 0).
2084 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2085 the conversion of RESULT to TYPE. */
2088 omit_one_operand (type, result, omitted)
2089 tree type, result, omitted;
2091 tree t = convert (type, result);
2093 if (TREE_SIDE_EFFECTS (omitted))
2094 return build (COMPOUND_EXPR, type, omitted, t);
2096 return non_lvalue (t);
2099 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2102 pedantic_omit_one_operand (type, result, omitted)
2103 tree type, result, omitted;
2105 tree t = convert (type, result);
2107 if (TREE_SIDE_EFFECTS (omitted))
2108 return build (COMPOUND_EXPR, type, omitted, t);
2110 return pedantic_non_lvalue (t);
2115 /* Return a simplified tree node for the truth-negation of ARG. This
2116 never alters ARG itself. We assume that ARG is an operation that
2117 returns a truth value (0 or 1). */
2120 invert_truthvalue (arg)
2123 tree type = TREE_TYPE (arg);
2124 enum tree_code code = TREE_CODE (arg);
2126 if (code == ERROR_MARK)
2129 /* If this is a comparison, we can simply invert it, except for
2130 floating-point non-equality comparisons, in which case we just
2131 enclose a TRUTH_NOT_EXPR around what we have. */
2133 if (TREE_CODE_CLASS (code) == '<')
2135 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2136 && code != NE_EXPR && code != EQ_EXPR)
2137 return build1 (TRUTH_NOT_EXPR, type, arg);
2139 return build (invert_tree_comparison (code), type,
2140 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2146 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2147 && TREE_INT_CST_HIGH (arg) == 0, 0));
2149 case TRUTH_AND_EXPR:
2150 return build (TRUTH_OR_EXPR, type,
2151 invert_truthvalue (TREE_OPERAND (arg, 0)),
2152 invert_truthvalue (TREE_OPERAND (arg, 1)));
2155 return build (TRUTH_AND_EXPR, type,
2156 invert_truthvalue (TREE_OPERAND (arg, 0)),
2157 invert_truthvalue (TREE_OPERAND (arg, 1)));
2159 case TRUTH_XOR_EXPR:
2160 /* Here we can invert either operand. We invert the first operand
2161 unless the second operand is a TRUTH_NOT_EXPR in which case our
2162 result is the XOR of the first operand with the inside of the
2163 negation of the second operand. */
2165 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2166 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2167 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2169 return build (TRUTH_XOR_EXPR, type,
2170 invert_truthvalue (TREE_OPERAND (arg, 0)),
2171 TREE_OPERAND (arg, 1));
2173 case TRUTH_ANDIF_EXPR:
2174 return build (TRUTH_ORIF_EXPR, type,
2175 invert_truthvalue (TREE_OPERAND (arg, 0)),
2176 invert_truthvalue (TREE_OPERAND (arg, 1)));
2178 case TRUTH_ORIF_EXPR:
2179 return build (TRUTH_ANDIF_EXPR, type,
2180 invert_truthvalue (TREE_OPERAND (arg, 0)),
2181 invert_truthvalue (TREE_OPERAND (arg, 1)));
2183 case TRUTH_NOT_EXPR:
2184 return TREE_OPERAND (arg, 0);
2187 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2188 invert_truthvalue (TREE_OPERAND (arg, 1)),
2189 invert_truthvalue (TREE_OPERAND (arg, 2)));
2192 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2193 invert_truthvalue (TREE_OPERAND (arg, 1)));
2195 case NON_LVALUE_EXPR:
2196 return invert_truthvalue (TREE_OPERAND (arg, 0));
2201 return build1 (TREE_CODE (arg), type,
2202 invert_truthvalue (TREE_OPERAND (arg, 0)));
2205 if (!integer_onep (TREE_OPERAND (arg, 1)))
2207 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2210 return build1 (TRUTH_NOT_EXPR, type, arg);
2212 case CLEANUP_POINT_EXPR:
2213 return build1 (CLEANUP_POINT_EXPR, type,
2214 invert_truthvalue (TREE_OPERAND (arg, 0)));
2216 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2218 return build1 (TRUTH_NOT_EXPR, type, arg);
2221 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2222 operands are another bit-wise operation with a common input. If so,
2223 distribute the bit operations to save an operation and possibly two if
2224 constants are involved. For example, convert
2225 (A | B) & (A | C) into A | (B & C)
2226 Further simplification will occur if B and C are constants.
2228 If this optimization cannot be done, 0 will be returned. */
2231 distribute_bit_expr (code, type, arg0, arg1)
2232 enum tree_code code;
2239 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2240 || TREE_CODE (arg0) == code
2241 || (TREE_CODE (arg0) != BIT_AND_EXPR
2242 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2245 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2247 common = TREE_OPERAND (arg0, 0);
2248 left = TREE_OPERAND (arg0, 1);
2249 right = TREE_OPERAND (arg1, 1);
2251 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2253 common = TREE_OPERAND (arg0, 0);
2254 left = TREE_OPERAND (arg0, 1);
2255 right = TREE_OPERAND (arg1, 0);
2257 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2259 common = TREE_OPERAND (arg0, 1);
2260 left = TREE_OPERAND (arg0, 0);
2261 right = TREE_OPERAND (arg1, 1);
2263 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2265 common = TREE_OPERAND (arg0, 1);
2266 left = TREE_OPERAND (arg0, 0);
2267 right = TREE_OPERAND (arg1, 0);
2272 return fold (build (TREE_CODE (arg0), type, common,
2273 fold (build (code, type, left, right))));
2276 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2277 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2280 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2283 int bitsize, bitpos;
2286 tree result = build (BIT_FIELD_REF, type, inner,
2287 size_int (bitsize), size_int (bitpos));
2289 TREE_UNSIGNED (result) = unsignedp;
2294 /* Optimize a bit-field compare.
2296 There are two cases: First is a compare against a constant and the
2297 second is a comparison of two items where the fields are at the same
2298 bit position relative to the start of a chunk (byte, halfword, word)
2299 large enough to contain it. In these cases we can avoid the shift
2300 implicit in bitfield extractions.
2302 For constants, we emit a compare of the shifted constant with the
2303 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2304 compared. For two fields at the same position, we do the ANDs with the
2305 similar mask and compare the result of the ANDs.
2307 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2308 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2309 are the left and right operands of the comparison, respectively.
2311 If the optimization described above can be done, we return the resulting
2312 tree. Otherwise we return zero. */
2315 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2316 enum tree_code code;
2320 int lbitpos, lbitsize, rbitpos, rbitsize;
2321 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2322 tree type = TREE_TYPE (lhs);
2323 tree signed_type, unsigned_type;
2324 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2325 enum machine_mode lmode, rmode, lnmode, rnmode;
2326 int lunsignedp, runsignedp;
2327 int lvolatilep = 0, rvolatilep = 0;
2329 tree linner, rinner;
2333 /* Get all the information about the extractions being done. If the bit size
2334 if the same as the size of the underlying object, we aren't doing an
2335 extraction at all and so can do nothing. */
2336 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2337 &lunsignedp, &lvolatilep, &alignment);
2338 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2344 /* If this is not a constant, we can only do something if bit positions,
2345 sizes, and signedness are the same. */
2346 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2347 &runsignedp, &rvolatilep, &alignment);
2349 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2350 || lunsignedp != runsignedp || offset != 0)
2354 /* See if we can find a mode to refer to this field. We should be able to,
2355 but fail if we can't. */
2356 lnmode = get_best_mode (lbitsize, lbitpos,
2357 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2359 if (lnmode == VOIDmode)
2362 /* Set signed and unsigned types of the precision of this mode for the
2364 signed_type = type_for_mode (lnmode, 0);
2365 unsigned_type = type_for_mode (lnmode, 1);
2369 rnmode = get_best_mode (rbitsize, rbitpos,
2370 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2372 if (rnmode == VOIDmode)
2376 /* Compute the bit position and size for the new reference and our offset
2377 within it. If the new reference is the same size as the original, we
2378 won't optimize anything, so return zero. */
2379 lnbitsize = GET_MODE_BITSIZE (lnmode);
2380 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2381 lbitpos -= lnbitpos;
2382 if (lnbitsize == lbitsize)
2387 rnbitsize = GET_MODE_BITSIZE (rnmode);
2388 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2389 rbitpos -= rnbitpos;
2390 if (rnbitsize == rbitsize)
2394 if (BYTES_BIG_ENDIAN)
2395 lbitpos = lnbitsize - lbitsize - lbitpos;
2397 /* Make the mask to be used against the extracted field. */
2398 mask = build_int_2 (~0, ~0);
2399 TREE_TYPE (mask) = unsigned_type;
2400 force_fit_type (mask, 0);
2401 mask = convert (unsigned_type, mask);
2402 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2403 mask = const_binop (RSHIFT_EXPR, mask,
2404 size_int (lnbitsize - lbitsize - lbitpos), 0);
2407 /* If not comparing with constant, just rework the comparison
2409 return build (code, compare_type,
2410 build (BIT_AND_EXPR, unsigned_type,
2411 make_bit_field_ref (linner, unsigned_type,
2412 lnbitsize, lnbitpos, 1),
2414 build (BIT_AND_EXPR, unsigned_type,
2415 make_bit_field_ref (rinner, unsigned_type,
2416 rnbitsize, rnbitpos, 1),
2419 /* Otherwise, we are handling the constant case. See if the constant is too
2420 big for the field. Warn and return a tree of for 0 (false) if so. We do
2421 this not only for its own sake, but to avoid having to test for this
2422 error case below. If we didn't, we might generate wrong code.
2424 For unsigned fields, the constant shifted right by the field length should
2425 be all zero. For signed fields, the high-order bits should agree with
2430 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2431 convert (unsigned_type, rhs),
2432 size_int (lbitsize), 0)))
2434 warning ("comparison is always %s due to width of bitfield",
2435 code == NE_EXPR ? "one" : "zero");
2436 return convert (compare_type,
2438 ? integer_one_node : integer_zero_node));
2443 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2444 size_int (lbitsize - 1), 0);
2445 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2447 warning ("comparison is always %s due to width of bitfield",
2448 code == NE_EXPR ? "one" : "zero");
2449 return convert (compare_type,
2451 ? integer_one_node : integer_zero_node));
2455 /* Single-bit compares should always be against zero. */
2456 if (lbitsize == 1 && ! integer_zerop (rhs))
2458 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2459 rhs = convert (type, integer_zero_node);
2462 /* Make a new bitfield reference, shift the constant over the
2463 appropriate number of bits and mask it with the computed mask
2464 (in case this was a signed field). If we changed it, make a new one. */
2465 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2468 TREE_SIDE_EFFECTS (lhs) = 1;
2469 TREE_THIS_VOLATILE (lhs) = 1;
2472 rhs = fold (const_binop (BIT_AND_EXPR,
2473 const_binop (LSHIFT_EXPR,
2474 convert (unsigned_type, rhs),
2475 size_int (lbitpos), 0),
2478 return build (code, compare_type,
2479 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2483 /* Subroutine for fold_truthop: decode a field reference.
2485 If EXP is a comparison reference, we return the innermost reference.
2487 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2488 set to the starting bit number.
2490 If the innermost field can be completely contained in a mode-sized
2491 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2493 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2494 otherwise it is not changed.
2496 *PUNSIGNEDP is set to the signedness of the field.
2498 *PMASK is set to the mask used. This is either contained in a
2499 BIT_AND_EXPR or derived from the width of the field.
2501 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2503 Return 0 if this is not a component reference or is one that we can't
2504 do anything with. */
2507 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2508 pvolatilep, pmask, pand_mask)
2510 int *pbitsize, *pbitpos;
2511 enum machine_mode *pmode;
2512 int *punsignedp, *pvolatilep;
2517 tree mask, inner, offset;
2522 /* All the optimizations using this function assume integer fields.
2523 There are problems with FP fields since the type_for_size call
2524 below can fail for, e.g., XFmode. */
2525 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2530 if (TREE_CODE (exp) == BIT_AND_EXPR)
2532 and_mask = TREE_OPERAND (exp, 1);
2533 exp = TREE_OPERAND (exp, 0);
2534 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2535 if (TREE_CODE (and_mask) != INTEGER_CST)
2540 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2541 punsignedp, pvolatilep, &alignment);
2542 if ((inner == exp && and_mask == 0)
2543 || *pbitsize < 0 || offset != 0)
2546 /* Compute the mask to access the bitfield. */
2547 unsigned_type = type_for_size (*pbitsize, 1);
2548 precision = TYPE_PRECISION (unsigned_type);
2550 mask = build_int_2 (~0, ~0);
2551 TREE_TYPE (mask) = unsigned_type;
2552 force_fit_type (mask, 0);
2553 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2554 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2556 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2558 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2559 convert (unsigned_type, and_mask), mask));
2562 *pand_mask = and_mask;
2566 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2570 all_ones_mask_p (mask, size)
2574 tree type = TREE_TYPE (mask);
2575 int precision = TYPE_PRECISION (type);
2578 tmask = build_int_2 (~0, ~0);
2579 TREE_TYPE (tmask) = signed_type (type);
2580 force_fit_type (tmask, 0);
2582 tree_int_cst_equal (mask,
2583 const_binop (RSHIFT_EXPR,
2584 const_binop (LSHIFT_EXPR, tmask,
2585 size_int (precision - size),
2587 size_int (precision - size), 0));
2590 /* Subroutine for fold_truthop: determine if an operand is simple enough
2591 to be evaluated unconditionally. */
2594 simple_operand_p (exp)
2597 /* Strip any conversions that don't change the machine mode. */
2598 while ((TREE_CODE (exp) == NOP_EXPR
2599 || TREE_CODE (exp) == CONVERT_EXPR)
2600 && (TYPE_MODE (TREE_TYPE (exp))
2601 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2602 exp = TREE_OPERAND (exp, 0);
2604 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2605 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2606 && ! TREE_ADDRESSABLE (exp)
2607 && ! TREE_THIS_VOLATILE (exp)
2608 && ! DECL_NONLOCAL (exp)
2609 /* Don't regard global variables as simple. They may be
2610 allocated in ways unknown to the compiler (shared memory,
2611 #pragma weak, etc). */
2612 && ! TREE_PUBLIC (exp)
2613 && ! DECL_EXTERNAL (exp)
2614 /* Loading a static variable is unduly expensive, but global
2615 registers aren't expensive. */
2616 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2619 /* The following functions are subroutines to fold_range_test and allow it to
2620 try to change a logical combination of comparisons into a range test.
2623 X == 2 && X == 3 && X == 4 && X == 5
2627 (unsigned) (X - 2) <= 3
2629 We decribe each set of comparisons as being either inside or outside
2630 a range, using a variable named like IN_P, and then describe the
2631 range with a lower and upper bound. If one of the bounds is omitted,
2632 it represents either the highest or lowest value of the type.
2634 In the comments below, we represent a range by two numbers in brackets
2635 preceeded by a "+" to designate being inside that range, or a "-" to
2636 designate being outside that range, so the condition can be inverted by
2637 flipping the prefix. An omitted bound is represented by a "-". For
2638 example, "- [-, 10]" means being outside the range starting at the lowest
2639 possible value and ending at 10, in other words, being greater than 10.
2640 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2643 We set up things so that the missing bounds are handled in a consistent
2644 manner so neither a missing bound nor "true" and "false" need to be
2645 handled using a special case. */
2647 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2648 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2649 and UPPER1_P are nonzero if the respective argument is an upper bound
2650 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2651 must be specified for a comparison. ARG1 will be converted to ARG0's
2652 type if both are specified. */
2655 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2656 enum tree_code code;
2659 int upper0_p, upper1_p;
2665 /* If neither arg represents infinity, do the normal operation.
2666 Else, if not a comparison, return infinity. Else handle the special
2667 comparison rules. Note that most of the cases below won't occur, but
2668 are handled for consistency. */
2670 if (arg0 != 0 && arg1 != 0)
2672 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2673 arg0, convert (TREE_TYPE (arg0), arg1)));
2675 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2678 if (TREE_CODE_CLASS (code) != '<')
2681 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2682 for neither. Then compute our result treating them as never equal
2683 and comparing bounds to non-bounds as above. */
2684 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2685 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2688 case EQ_EXPR: case NE_EXPR:
2689 result = (code == NE_EXPR);
2691 case LT_EXPR: case LE_EXPR:
2692 result = sgn0 < sgn1;
2694 case GT_EXPR: case GE_EXPR:
2695 result = sgn0 > sgn1;
2699 return convert (type, result ? integer_one_node : integer_zero_node);
2702 /* Given EXP, a logical expression, set the range it is testing into
2703 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2704 actually being tested. *PLOW and *PHIGH will have be made the same type
2705 as the returned expression. If EXP is not a comparison, we will most
2706 likely not be returning a useful value and range. */
2709 make_range (exp, pin_p, plow, phigh)
2714 enum tree_code code;
2715 tree arg0, arg1, type;
2717 tree low, high, n_low, n_high;
2719 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2720 and see if we can refine the range. Some of the cases below may not
2721 happen, but it doesn't seem worth worrying about this. We "continue"
2722 the outer loop when we've changed something; otherwise we "break"
2723 the switch, which will "break" the while. */
2725 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2729 code = TREE_CODE (exp);
2730 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2731 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2732 || TREE_CODE_CLASS (code) == '2')
2733 type = TREE_TYPE (arg0);
2737 case TRUTH_NOT_EXPR:
2738 in_p = ! in_p, exp = arg0;
2741 case EQ_EXPR: case NE_EXPR:
2742 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2743 /* We can only do something if the range is testing for zero
2744 and if the second operand is an integer constant. Note that
2745 saying something is "in" the range we make is done by
2746 complementing IN_P since it will set in the initial case of
2747 being not equal to zero; "out" is leaving it alone. */
2748 if (low == 0 || high == 0
2749 || ! integer_zerop (low) || ! integer_zerop (high)
2750 || TREE_CODE (arg1) != INTEGER_CST)
2755 case NE_EXPR: /* - [c, c] */
2758 case EQ_EXPR: /* + [c, c] */
2759 in_p = ! in_p, low = high = arg1;
2761 case GT_EXPR: /* - [-, c] */
2762 low = 0, high = arg1;
2764 case GE_EXPR: /* + [c, -] */
2765 in_p = ! in_p, low = arg1, high = 0;
2767 case LT_EXPR: /* - [c, -] */
2768 low = arg1, high = 0;
2770 case LE_EXPR: /* + [-, c] */
2771 in_p = ! in_p, low = 0, high = arg1;
2777 /* If this is an unsigned comparison, we also know that EXP is
2778 greater than or equal to zero. We base the range tests we make
2779 on that fact, so we record it here so we can parse existing
2781 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2783 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2784 1, convert (type, integer_zero_node),
2788 in_p = n_in_p, low = n_low, high = n_high;
2790 /* If the high bound is missing, reverse the range so it
2791 goes from zero to the low bound minus 1. */
2795 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2796 integer_one_node, 0);
2797 low = convert (type, integer_zero_node);
2803 /* (-x) IN [a,b] -> x in [-b, -a] */
2804 n_low = range_binop (MINUS_EXPR, type,
2805 convert (type, integer_zero_node), 0, high, 1);
2806 n_high = range_binop (MINUS_EXPR, type,
2807 convert (type, integer_zero_node), 0, low, 0);
2808 low = n_low, high = n_high;
2814 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2815 convert (type, integer_one_node));
2818 case PLUS_EXPR: case MINUS_EXPR:
2819 if (TREE_CODE (arg1) != INTEGER_CST)
2822 /* If EXP is signed, any overflow in the computation is undefined,
2823 so we don't worry about it so long as our computations on
2824 the bounds don't overflow. For unsigned, overflow is defined
2825 and this is exactly the right thing. */
2826 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2827 type, low, 0, arg1, 0);
2828 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2829 type, high, 1, arg1, 0);
2830 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2831 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2834 /* Check for an unsigned range which has wrapped around the maximum
2835 value thus making n_high < n_low, and normalize it. */
2836 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2838 low = range_binop (PLUS_EXPR, type, n_high, 0,
2839 integer_one_node, 0);
2840 high = range_binop (MINUS_EXPR, type, n_low, 0,
2841 integer_one_node, 0);
2845 low = n_low, high = n_high;
2850 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2851 if (! INTEGRAL_TYPE_P (type)
2852 || (low != 0 && ! int_fits_type_p (low, type))
2853 || (high != 0 && ! int_fits_type_p (high, type)))
2857 low = convert (type, low);
2860 high = convert (type, high);
2869 /* If EXP is a constant, we can evaluate whether this is true or false. */
2870 if (TREE_CODE (exp) == INTEGER_CST)
2872 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2874 && integer_onep (range_binop (LE_EXPR, integer_type_node,
2880 *pin_p = in_p, *plow = low, *phigh = high;
2884 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
2885 type, TYPE, return an expression to test if EXP is in (or out of, depending
2886 on IN_P) the range. */
2889 build_range_check (type, exp, in_p, low, high)
2895 tree etype = TREE_TYPE (exp);
2899 && (0 != (value = build_range_check (type, exp, 1, low, high))))
2900 return invert_truthvalue (value);
2902 else if (low == 0 && high == 0)
2903 return convert (type, integer_one_node);
2906 return fold (build (LE_EXPR, type, exp, high));
2909 return fold (build (GE_EXPR, type, exp, low));
2911 else if (operand_equal_p (low, high, 0))
2912 return fold (build (EQ_EXPR, type, exp, low));
2914 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
2915 return build_range_check (type, exp, 1, 0, high);
2917 else if (integer_zerop (low))
2919 utype = unsigned_type (etype);
2920 return build_range_check (type, convert (utype, exp), 1, 0,
2921 convert (utype, high));
2924 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
2925 && ! TREE_OVERFLOW (value))
2926 return build_range_check (type,
2927 fold (build (MINUS_EXPR, etype, exp, low)),
2928 1, convert (etype, integer_zero_node), value);
2933 /* Given two ranges, see if we can merge them into one. Return 1 if we
2934 can, 0 if we can't. Set the output range into the specified parameters. */
2937 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
2941 tree low0, high0, low1, high1;
2950 /* Make range 0 be the range that starts first. Swap them if it isn't. */
2951 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
2953 || (((low0 == 0 && low1 == 0)
2954 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
2956 && integer_onep (range_binop (GT_EXPR, integer_type_node,
2957 high0, 1, high1, 1))))
2959 temp = in0_p, in0_p = in1_p, in1_p = temp;
2960 tem = low0, low0 = low1, low1 = tem;
2961 tem = high0, high0 = high1, high1 = tem;
2964 /* Now flag two cases, whether the ranges are disjoint or whether the
2965 second range is totally subsumed in the first. Note that the tests
2966 below are simplified by the ones above. */
2967 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
2968 high0, 1, low1, 0));
2969 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
2970 high1, 1, high0, 1));
2972 /* We now have four cases, depending on whether we are including or
2973 excluding the two ranges. */
2976 /* If they don't overlap, the result is false. If the second range
2977 is a subset it is the result. Otherwise, the range is from the start
2978 of the second to the end of the first. */
2980 in_p = 0, low = high = 0;
2982 in_p = 1, low = low1, high = high1;
2984 in_p = 1, low = low1, high = high0;
2987 else if (in0_p && ! in1_p)
2989 /* If they don't overlap, the result is the first range. If the
2990 second range is a subset of the first, we can't describe this as
2991 a single range unless both ranges end at the same place. If both
2992 ranges start in the same place, then the result is false.
2993 Otherwise, we go from the start of the first range to just before
2994 the start of the second. */
2996 in_p = 1, low = low0, high = high0;
2998 && integer_zerop (range_binop (EQ_EXPR, integer_type_node,
2999 high0, 1, high1, 0)))
3001 else if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3003 in_p = 0, low = high = 0;
3006 in_p = 1, low = low0;
3007 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3008 integer_one_node, 0);
3012 else if (! in0_p && in1_p)
3014 /* If they don't overlap, the result is the second range. If the second
3015 is a subset of the first, the result is false. Otherwise,
3016 the range starts just after the first range and ends at the
3017 end of the second. */
3019 in_p = 1, low = low1, high = high1;
3021 in_p = 0, low = high = 0;
3024 in_p = 1, high = high1;
3025 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3026 integer_one_node, 0);
3032 /* The case where we are excluding both ranges. Here the complex case
3033 is if they don't overlap. In that case, the only time we have a
3034 range is if they are adjacent. If the second is a subset of the
3035 first, the result is the first. Otherwise, the range to exclude
3036 starts at the beginning of the first range and ends at the end of the
3040 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3041 range_binop (PLUS_EXPR, NULL_TREE,
3043 integer_one_node, 1),
3045 in_p = 0, low = low0, high = high1;
3050 in_p = 0, low = low0, high = high0;
3052 in_p = 0, low = low0, high = high1;
3055 *pin_p = in_p, *plow = low, *phigh = high;
3059 /* EXP is some logical combination of boolean tests. See if we can
3060 merge it into some range test. Return the new tree if so. */
3063 fold_range_test (exp)
3066 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3067 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3068 int in0_p, in1_p, in_p;
3069 tree low0, low1, low, high0, high1, high;
3070 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3071 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3074 /* If this is an OR operation, invert both sides; we will invert
3075 again at the end. */
3077 in0_p = ! in0_p, in1_p = ! in1_p;
3079 /* If both expressions are the same, if we can merge the ranges, and we
3080 can build the range test, return it or it inverted. If one of the
3081 ranges is always true or always false, consider it to be the same
3082 expression as the other. */
3083 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3084 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3086 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3088 : rhs != 0 ? rhs : integer_zero_node,
3090 return or_op ? invert_truthvalue (tem) : tem;
3092 /* On machines where the branch cost is expensive, if this is a
3093 short-circuited branch and the underlying object on both sides
3094 is the same, make a non-short-circuit operation. */
3095 else if (BRANCH_COST >= 2
3096 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3097 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3098 && operand_equal_p (lhs, rhs, 0))
3100 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR. */
3101 if (simple_operand_p (lhs))
3102 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3103 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3104 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3105 TREE_OPERAND (exp, 1));
3108 tree common = save_expr (lhs);
3110 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3111 or_op ? ! in0_p : in0_p,
3113 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3114 or_op ? ! in1_p : in1_p,
3116 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3117 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3118 TREE_TYPE (exp), lhs, rhs);
3125 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3126 bit value. Arrange things so the extra bits will be set to zero if and
3127 only if C is signed-extended to its full width. If MASK is nonzero,
3128 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3131 unextend (c, p, unsignedp, mask)
3137 tree type = TREE_TYPE (c);
3138 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3141 if (p == modesize || unsignedp)
3144 /* We work by getting just the sign bit into the low-order bit, then
3145 into the high-order bit, then sign-extend. We then XOR that value
3147 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3148 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3150 /* We must use a signed type in order to get an arithmetic right shift.
3151 However, we must also avoid introducing accidental overflows, so that
3152 a subsequent call to integer_zerop will work. Hence we must
3153 do the type conversion here. At this point, the constant is either
3154 zero or one, and the conversion to a signed type can never overflow.
3155 We could get an overflow if this conversion is done anywhere else. */
3156 if (TREE_UNSIGNED (type))
3157 temp = convert (signed_type (type), temp);
3159 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3160 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3162 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3163 /* If necessary, convert the type back to match the type of C. */
3164 if (TREE_UNSIGNED (type))
3165 temp = convert (type, temp);
3167 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3170 /* Find ways of folding logical expressions of LHS and RHS:
3171 Try to merge two comparisons to the same innermost item.
3172 Look for range tests like "ch >= '0' && ch <= '9'".
3173 Look for combinations of simple terms on machines with expensive branches
3174 and evaluate the RHS unconditionally.
3176 For example, if we have p->a == 2 && p->b == 4 and we can make an
3177 object large enough to span both A and B, we can do this with a comparison
3178 against the object ANDed with the a mask.
3180 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3181 operations to do this with one comparison.
3183 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3184 function and the one above.
3186 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3187 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3189 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3192 We return the simplified tree or 0 if no optimization is possible. */
3195 fold_truthop (code, truth_type, lhs, rhs)
3196 enum tree_code code;
3197 tree truth_type, lhs, rhs;
3199 /* If this is the "or" of two comparisons, we can do something if we
3200 the comparisons are NE_EXPR. If this is the "and", we can do something
3201 if the comparisons are EQ_EXPR. I.e.,
3202 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3204 WANTED_CODE is this operation code. For single bit fields, we can
3205 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3206 comparison for one-bit fields. */
3208 enum tree_code wanted_code;
3209 enum tree_code lcode, rcode;
3210 tree ll_arg, lr_arg, rl_arg, rr_arg;
3211 tree ll_inner, lr_inner, rl_inner, rr_inner;
3212 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3213 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3214 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3215 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3216 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3217 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3218 enum machine_mode lnmode, rnmode;
3219 tree ll_mask, lr_mask, rl_mask, rr_mask;
3220 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3221 tree l_const, r_const;
3223 int first_bit, end_bit;
3226 /* Start by getting the comparison codes. Fail if anything is volatile.
3227 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3228 it were surrounded with a NE_EXPR. */
3230 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3233 lcode = TREE_CODE (lhs);
3234 rcode = TREE_CODE (rhs);
3236 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3237 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3239 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3240 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3242 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3245 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3246 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3248 ll_arg = TREE_OPERAND (lhs, 0);
3249 lr_arg = TREE_OPERAND (lhs, 1);
3250 rl_arg = TREE_OPERAND (rhs, 0);
3251 rr_arg = TREE_OPERAND (rhs, 1);
3253 /* If the RHS can be evaluated unconditionally and its operands are
3254 simple, it wins to evaluate the RHS unconditionally on machines
3255 with expensive branches. In this case, this isn't a comparison
3256 that can be merged. */
3258 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3259 are with zero (tmw). */
3261 if (BRANCH_COST >= 2
3262 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3263 && simple_operand_p (rl_arg)
3264 && simple_operand_p (rr_arg))
3265 return build (code, truth_type, lhs, rhs);
3267 /* See if the comparisons can be merged. Then get all the parameters for
3270 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3271 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3275 ll_inner = decode_field_reference (ll_arg,
3276 &ll_bitsize, &ll_bitpos, &ll_mode,
3277 &ll_unsignedp, &volatilep, &ll_mask,
3279 lr_inner = decode_field_reference (lr_arg,
3280 &lr_bitsize, &lr_bitpos, &lr_mode,
3281 &lr_unsignedp, &volatilep, &lr_mask,
3283 rl_inner = decode_field_reference (rl_arg,
3284 &rl_bitsize, &rl_bitpos, &rl_mode,
3285 &rl_unsignedp, &volatilep, &rl_mask,
3287 rr_inner = decode_field_reference (rr_arg,
3288 &rr_bitsize, &rr_bitpos, &rr_mode,
3289 &rr_unsignedp, &volatilep, &rr_mask,
3292 /* It must be true that the inner operation on the lhs of each
3293 comparison must be the same if we are to be able to do anything.
3294 Then see if we have constants. If not, the same must be true for
3296 if (volatilep || ll_inner == 0 || rl_inner == 0
3297 || ! operand_equal_p (ll_inner, rl_inner, 0))
3300 if (TREE_CODE (lr_arg) == INTEGER_CST
3301 && TREE_CODE (rr_arg) == INTEGER_CST)
3302 l_const = lr_arg, r_const = rr_arg;
3303 else if (lr_inner == 0 || rr_inner == 0
3304 || ! operand_equal_p (lr_inner, rr_inner, 0))
3307 l_const = r_const = 0;
3309 /* If either comparison code is not correct for our logical operation,
3310 fail. However, we can convert a one-bit comparison against zero into
3311 the opposite comparison against that bit being set in the field. */
3313 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3314 if (lcode != wanted_code)
3316 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3322 if (rcode != wanted_code)
3324 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3330 /* See if we can find a mode that contains both fields being compared on
3331 the left. If we can't, fail. Otherwise, update all constants and masks
3332 to be relative to a field of that size. */
3333 first_bit = MIN (ll_bitpos, rl_bitpos);
3334 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3335 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3336 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3338 if (lnmode == VOIDmode)
3341 lnbitsize = GET_MODE_BITSIZE (lnmode);
3342 lnbitpos = first_bit & ~ (lnbitsize - 1);
3343 type = type_for_size (lnbitsize, 1);
3344 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3346 if (BYTES_BIG_ENDIAN)
3348 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3349 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3352 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3353 size_int (xll_bitpos), 0);
3354 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3355 size_int (xrl_bitpos), 0);
3359 l_const = convert (type, l_const);
3360 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3361 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3362 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3363 fold (build1 (BIT_NOT_EXPR,
3367 warning ("comparison is always %s",
3368 wanted_code == NE_EXPR ? "one" : "zero");
3370 return convert (truth_type,
3371 wanted_code == NE_EXPR
3372 ? integer_one_node : integer_zero_node);
3377 r_const = convert (type, r_const);
3378 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3379 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3380 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3381 fold (build1 (BIT_NOT_EXPR,
3385 warning ("comparison is always %s",
3386 wanted_code == NE_EXPR ? "one" : "zero");
3388 return convert (truth_type,
3389 wanted_code == NE_EXPR
3390 ? integer_one_node : integer_zero_node);
3394 /* If the right sides are not constant, do the same for it. Also,
3395 disallow this optimization if a size or signedness mismatch occurs
3396 between the left and right sides. */
3399 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3400 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3401 /* Make sure the two fields on the right
3402 correspond to the left without being swapped. */
3403 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3406 first_bit = MIN (lr_bitpos, rr_bitpos);
3407 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3408 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3409 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3411 if (rnmode == VOIDmode)
3414 rnbitsize = GET_MODE_BITSIZE (rnmode);
3415 rnbitpos = first_bit & ~ (rnbitsize - 1);
3416 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3418 if (BYTES_BIG_ENDIAN)
3420 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3421 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3424 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3425 size_int (xlr_bitpos), 0);
3426 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3427 size_int (xrr_bitpos), 0);
3429 /* Make a mask that corresponds to both fields being compared.
3430 Do this for both items being compared. If the masks agree,
3431 we can do this by masking both and comparing the masked
3433 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3434 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3435 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3437 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3438 ll_unsignedp || rl_unsignedp);
3439 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3440 lr_unsignedp || rr_unsignedp);
3441 if (! all_ones_mask_p (ll_mask, lnbitsize))
3443 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3444 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3446 return build (wanted_code, truth_type, lhs, rhs);
3449 /* There is still another way we can do something: If both pairs of
3450 fields being compared are adjacent, we may be able to make a wider
3451 field containing them both. */
3452 if ((ll_bitsize + ll_bitpos == rl_bitpos
3453 && lr_bitsize + lr_bitpos == rr_bitpos)
3454 || (ll_bitpos == rl_bitpos + rl_bitsize
3455 && lr_bitpos == rr_bitpos + rr_bitsize))
3456 return build (wanted_code, truth_type,
3457 make_bit_field_ref (ll_inner, type,
3458 ll_bitsize + rl_bitsize,
3459 MIN (ll_bitpos, rl_bitpos),
3461 make_bit_field_ref (lr_inner, type,
3462 lr_bitsize + rr_bitsize,
3463 MIN (lr_bitpos, rr_bitpos),
3469 /* Handle the case of comparisons with constants. If there is something in
3470 common between the masks, those bits of the constants must be the same.
3471 If not, the condition is always false. Test for this to avoid generating
3472 incorrect code below. */
3473 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3474 if (! integer_zerop (result)
3475 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3476 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3478 if (wanted_code == NE_EXPR)
3480 warning ("`or' of unmatched not-equal tests is always 1");
3481 return convert (truth_type, integer_one_node);
3485 warning ("`and' of mutually exclusive equal-tests is always zero");
3486 return convert (truth_type, integer_zero_node);
3490 /* Construct the expression we will return. First get the component
3491 reference we will make. Unless the mask is all ones the width of
3492 that field, perform the mask operation. Then compare with the
3494 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3495 ll_unsignedp || rl_unsignedp);
3497 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3498 if (! all_ones_mask_p (ll_mask, lnbitsize))
3499 result = build (BIT_AND_EXPR, type, result, ll_mask);
3501 return build (wanted_code, truth_type, result,
3502 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3505 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3506 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3507 that we may sometimes modify the tree. */
3510 strip_compound_expr (t, s)
3514 tree type = TREE_TYPE (t);
3515 enum tree_code code = TREE_CODE (t);
3517 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3518 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3519 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3520 return TREE_OPERAND (t, 1);
3522 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3523 don't bother handling any other types. */
3524 else if (code == COND_EXPR)
3526 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3527 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3528 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3530 else if (TREE_CODE_CLASS (code) == '1')
3531 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3532 else if (TREE_CODE_CLASS (code) == '<'
3533 || TREE_CODE_CLASS (code) == '2')
3535 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3536 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3542 /* Perform constant folding and related simplification of EXPR.
3543 The related simplifications include x*1 => x, x*0 => 0, etc.,
3544 and application of the associative law.
3545 NOP_EXPR conversions may be removed freely (as long as we
3546 are careful not to change the C type of the overall expression)
3547 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3548 but we can constant-fold them if they have constant operands. */
3554 register tree t = expr;
3555 tree t1 = NULL_TREE;
3557 tree type = TREE_TYPE (expr);
3558 register tree arg0, arg1;
3559 register enum tree_code code = TREE_CODE (t);
3563 /* WINS will be nonzero when the switch is done
3564 if all operands are constant. */
3568 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3569 Likewise for a SAVE_EXPR that's already been evaluated. */
3570 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3573 /* Return right away if already constant. */
3574 if (TREE_CONSTANT (t))
3576 if (code == CONST_DECL)
3577 return DECL_INITIAL (t);
3581 kind = TREE_CODE_CLASS (code);
3582 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3586 /* Special case for conversion ops that can have fixed point args. */
3587 arg0 = TREE_OPERAND (t, 0);
3589 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3591 STRIP_TYPE_NOPS (arg0);
3593 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3594 subop = TREE_REALPART (arg0);
3598 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3599 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3600 && TREE_CODE (subop) != REAL_CST
3601 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3603 /* Note that TREE_CONSTANT isn't enough:
3604 static var addresses are constant but we can't
3605 do arithmetic on them. */
3608 else if (kind == 'e' || kind == '<'
3609 || kind == '1' || kind == '2' || kind == 'r')
3611 register int len = tree_code_length[(int) code];
3613 for (i = 0; i < len; i++)
3615 tree op = TREE_OPERAND (t, i);
3619 continue; /* Valid for CALL_EXPR, at least. */
3621 if (kind == '<' || code == RSHIFT_EXPR)
3623 /* Signedness matters here. Perhaps we can refine this
3625 STRIP_TYPE_NOPS (op);
3629 /* Strip any conversions that don't change the mode. */
3633 if (TREE_CODE (op) == COMPLEX_CST)
3634 subop = TREE_REALPART (op);
3638 if (TREE_CODE (subop) != INTEGER_CST
3639 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3640 && TREE_CODE (subop) != REAL_CST
3641 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3643 /* Note that TREE_CONSTANT isn't enough:
3644 static var addresses are constant but we can't
3645 do arithmetic on them. */
3655 /* If this is a commutative operation, and ARG0 is a constant, move it
3656 to ARG1 to reduce the number of tests below. */
3657 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3658 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3659 || code == BIT_AND_EXPR)
3660 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3662 tem = arg0; arg0 = arg1; arg1 = tem;
3664 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3665 TREE_OPERAND (t, 1) = tem;
3668 /* Now WINS is set as described above,
3669 ARG0 is the first operand of EXPR,
3670 and ARG1 is the second operand (if it has more than one operand).
3672 First check for cases where an arithmetic operation is applied to a
3673 compound, conditional, or comparison operation. Push the arithmetic
3674 operation inside the compound or conditional to see if any folding
3675 can then be done. Convert comparison to conditional for this purpose.
3676 The also optimizes non-constant cases that used to be done in
3679 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3680 one of the operands is a comparison and the other is a comparison, a
3681 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3682 code below would make the expression more complex. Change it to a
3683 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3684 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3686 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3687 || code == EQ_EXPR || code == NE_EXPR)
3688 && ((truth_value_p (TREE_CODE (arg0))
3689 && (truth_value_p (TREE_CODE (arg1))
3690 || (TREE_CODE (arg1) == BIT_AND_EXPR
3691 && integer_onep (TREE_OPERAND (arg1, 1)))))
3692 || (truth_value_p (TREE_CODE (arg1))
3693 && (truth_value_p (TREE_CODE (arg0))
3694 || (TREE_CODE (arg0) == BIT_AND_EXPR
3695 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3697 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3698 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3702 if (code == EQ_EXPR)
3703 t = invert_truthvalue (t);
3708 if (TREE_CODE_CLASS (code) == '1')
3710 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3711 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3712 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3713 else if (TREE_CODE (arg0) == COND_EXPR)
3715 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3716 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3717 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3719 /* If this was a conversion, and all we did was to move into
3720 inside the COND_EXPR, bring it back out. But leave it if
3721 it is a conversion from integer to integer and the
3722 result precision is no wider than a word since such a
3723 conversion is cheap and may be optimized away by combine,
3724 while it couldn't if it were outside the COND_EXPR. Then return
3725 so we don't get into an infinite recursion loop taking the
3726 conversion out and then back in. */
3728 if ((code == NOP_EXPR || code == CONVERT_EXPR
3729 || code == NON_LVALUE_EXPR)
3730 && TREE_CODE (t) == COND_EXPR
3731 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3732 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3733 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3734 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3735 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3736 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3737 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3738 t = build1 (code, type,
3740 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3741 TREE_OPERAND (t, 0),
3742 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3743 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3746 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3747 return fold (build (COND_EXPR, type, arg0,
3748 fold (build1 (code, type, integer_one_node)),
3749 fold (build1 (code, type, integer_zero_node))));
3751 else if (TREE_CODE_CLASS (code) == '2'
3752 || TREE_CODE_CLASS (code) == '<')
3754 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3755 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3756 fold (build (code, type,
3757 arg0, TREE_OPERAND (arg1, 1))));
3758 else if (TREE_CODE (arg1) == COND_EXPR
3759 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3760 && TREE_CODE_CLASS (code) != '<'))
3762 tree test, true_value, false_value;
3764 if (TREE_CODE (arg1) == COND_EXPR)
3766 test = TREE_OPERAND (arg1, 0);
3767 true_value = TREE_OPERAND (arg1, 1);
3768 false_value = TREE_OPERAND (arg1, 2);
3772 tree testtype = TREE_TYPE (arg1);
3774 true_value = convert (testtype, integer_one_node);
3775 false_value = convert (testtype, integer_zero_node);
3778 /* If ARG0 is complex we want to make sure we only evaluate
3779 it once. Though this is only required if it is volatile, it
3780 might be more efficient even if it is not. However, if we
3781 succeed in folding one part to a constant, we do not need
3782 to make this SAVE_EXPR. Since we do this optimization
3783 primarily to see if we do end up with constant and this
3784 SAVE_EXPR interferes with later optimizations, suppressing
3785 it when we can is important. */
3787 if (TREE_CODE (arg0) != SAVE_EXPR
3788 && ((TREE_CODE (arg0) != VAR_DECL
3789 && TREE_CODE (arg0) != PARM_DECL)
3790 || TREE_SIDE_EFFECTS (arg0)))
3792 tree lhs = fold (build (code, type, arg0, true_value));
3793 tree rhs = fold (build (code, type, arg0, false_value));
3795 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3796 return fold (build (COND_EXPR, type, test, lhs, rhs));
3798 arg0 = save_expr (arg0);
3801 test = fold (build (COND_EXPR, type, test,
3802 fold (build (code, type, arg0, true_value)),
3803 fold (build (code, type, arg0, false_value))));
3804 if (TREE_CODE (arg0) == SAVE_EXPR)
3805 return build (COMPOUND_EXPR, type,
3806 convert (void_type_node, arg0),
3807 strip_compound_expr (test, arg0));
3809 return convert (type, test);
3812 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3813 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3814 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3815 else if (TREE_CODE (arg0) == COND_EXPR
3816 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3817 && TREE_CODE_CLASS (code) != '<'))
3819 tree test, true_value, false_value;
3821 if (TREE_CODE (arg0) == COND_EXPR)
3823 test = TREE_OPERAND (arg0, 0);
3824 true_value = TREE_OPERAND (arg0, 1);
3825 false_value = TREE_OPERAND (arg0, 2);
3829 tree testtype = TREE_TYPE (arg0);
3831 true_value = convert (testtype, integer_one_node);
3832 false_value = convert (testtype, integer_zero_node);
3835 if (TREE_CODE (arg1) != SAVE_EXPR
3836 && ((TREE_CODE (arg1) != VAR_DECL
3837 && TREE_CODE (arg1) != PARM_DECL)
3838 || TREE_SIDE_EFFECTS (arg1)))
3840 tree lhs = fold (build (code, type, true_value, arg1));
3841 tree rhs = fold (build (code, type, false_value, arg1));
3843 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
3844 || TREE_CONSTANT (arg1))
3845 return fold (build (COND_EXPR, type, test, lhs, rhs));
3847 arg1 = save_expr (arg1);
3850 test = fold (build (COND_EXPR, type, test,
3851 fold (build (code, type, true_value, arg1)),
3852 fold (build (code, type, false_value, arg1))));
3853 if (TREE_CODE (arg1) == SAVE_EXPR)
3854 return build (COMPOUND_EXPR, type,
3855 convert (void_type_node, arg1),
3856 strip_compound_expr (test, arg1));
3858 return convert (type, test);
3861 else if (TREE_CODE_CLASS (code) == '<'
3862 && TREE_CODE (arg0) == COMPOUND_EXPR)
3863 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3864 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3865 else if (TREE_CODE_CLASS (code) == '<'
3866 && TREE_CODE (arg1) == COMPOUND_EXPR)
3867 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3868 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3880 return fold (DECL_INITIAL (t));
3885 case FIX_TRUNC_EXPR:
3886 /* Other kinds of FIX are not handled properly by fold_convert. */
3888 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
3889 return TREE_OPERAND (t, 0);
3891 /* Handle cases of two conversions in a row. */
3892 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
3893 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
3895 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3896 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
3897 tree final_type = TREE_TYPE (t);
3898 int inside_int = INTEGRAL_TYPE_P (inside_type);
3899 int inside_ptr = POINTER_TYPE_P (inside_type);
3900 int inside_float = FLOAT_TYPE_P (inside_type);
3901 int inside_prec = TYPE_PRECISION (inside_type);
3902 int inside_unsignedp = TREE_UNSIGNED (inside_type);
3903 int inter_int = INTEGRAL_TYPE_P (inter_type);
3904 int inter_ptr = POINTER_TYPE_P (inter_type);
3905 int inter_float = FLOAT_TYPE_P (inter_type);
3906 int inter_prec = TYPE_PRECISION (inter_type);
3907 int inter_unsignedp = TREE_UNSIGNED (inter_type);
3908 int final_int = INTEGRAL_TYPE_P (final_type);
3909 int final_ptr = POINTER_TYPE_P (final_type);
3910 int final_float = FLOAT_TYPE_P (final_type);
3911 int final_prec = TYPE_PRECISION (final_type);
3912 int final_unsignedp = TREE_UNSIGNED (final_type);
3914 /* In addition to the cases of two conversions in a row
3915 handled below, if we are converting something to its own
3916 type via an object of identical or wider precision, neither
3917 conversion is needed. */
3918 if (inside_type == final_type
3919 && ((inter_int && final_int) || (inter_float && final_float))
3920 && inter_prec >= final_prec)
3921 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
3923 /* Likewise, if the intermediate and final types are either both
3924 float or both integer, we don't need the middle conversion if
3925 it is wider than the final type and doesn't change the signedness
3926 (for integers). Avoid this if the final type is a pointer
3927 since then we sometimes need the inner conversion. Likewise if
3928 the outer has a precision not equal to the size of its mode. */
3929 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
3930 || (inter_float && inside_float))
3931 && inter_prec >= inside_prec
3932 && (inter_float || inter_unsignedp == inside_unsignedp)
3933 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
3934 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
3936 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3938 /* Two conversions in a row are not needed unless:
3939 - some conversion is floating-point (overstrict for now), or
3940 - the intermediate type is narrower than both initial and
3942 - the intermediate type and innermost type differ in signedness,
3943 and the outermost type is wider than the intermediate, or
3944 - the initial type is a pointer type and the precisions of the
3945 intermediate and final types differ, or
3946 - the final type is a pointer type and the precisions of the
3947 initial and intermediate types differ. */
3948 if (! inside_float && ! inter_float && ! final_float
3949 && (inter_prec > inside_prec || inter_prec > final_prec)
3950 && ! (inside_int && inter_int
3951 && inter_unsignedp != inside_unsignedp
3952 && inter_prec < final_prec)
3953 && ((inter_unsignedp && inter_prec > inside_prec)
3954 == (final_unsignedp && final_prec > inter_prec))
3955 && ! (inside_ptr && inter_prec != final_prec)
3956 && ! (final_ptr && inside_prec != inter_prec)
3957 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
3958 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
3960 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3963 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
3964 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
3965 /* Detect assigning a bitfield. */
3966 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
3967 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
3969 /* Don't leave an assignment inside a conversion
3970 unless assigning a bitfield. */
3971 tree prev = TREE_OPERAND (t, 0);
3972 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
3973 /* First do the assignment, then return converted constant. */
3974 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
3980 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
3983 return fold_convert (t, arg0);
3985 #if 0 /* This loses on &"foo"[0]. */
3990 /* Fold an expression like: "foo"[2] */
3991 if (TREE_CODE (arg0) == STRING_CST
3992 && TREE_CODE (arg1) == INTEGER_CST
3993 && !TREE_INT_CST_HIGH (arg1)
3994 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
3996 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
3997 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
3998 force_fit_type (t, 0);
4005 if (TREE_CODE (arg0) == CONSTRUCTOR)
4007 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4014 TREE_CONSTANT (t) = wins;
4020 if (TREE_CODE (arg0) == INTEGER_CST)
4022 HOST_WIDE_INT low, high;
4023 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4024 TREE_INT_CST_HIGH (arg0),
4026 t = build_int_2 (low, high);
4027 TREE_TYPE (t) = type;
4029 = (TREE_OVERFLOW (arg0)
4030 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4031 TREE_CONSTANT_OVERFLOW (t)
4032 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4034 else if (TREE_CODE (arg0) == REAL_CST)
4035 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4037 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4038 return TREE_OPERAND (arg0, 0);
4040 /* Convert - (a - b) to (b - a) for non-floating-point. */
4041 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4042 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4043 TREE_OPERAND (arg0, 0));
4050 if (TREE_CODE (arg0) == INTEGER_CST)
4052 if (! TREE_UNSIGNED (type)
4053 && TREE_INT_CST_HIGH (arg0) < 0)
4055 HOST_WIDE_INT low, high;
4056 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4057 TREE_INT_CST_HIGH (arg0),
4059 t = build_int_2 (low, high);
4060 TREE_TYPE (t) = type;
4062 = (TREE_OVERFLOW (arg0)
4063 | force_fit_type (t, overflow));
4064 TREE_CONSTANT_OVERFLOW (t)
4065 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4068 else if (TREE_CODE (arg0) == REAL_CST)
4070 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4071 t = build_real (type,
4072 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4075 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4076 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4080 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4082 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4083 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4084 TREE_OPERAND (arg0, 0),
4085 fold (build1 (NEGATE_EXPR,
4086 TREE_TYPE (TREE_TYPE (arg0)),
4087 TREE_OPERAND (arg0, 1))));
4088 else if (TREE_CODE (arg0) == COMPLEX_CST)
4089 return build_complex (type, TREE_OPERAND (arg0, 0),
4090 fold (build1 (NEGATE_EXPR,
4091 TREE_TYPE (TREE_TYPE (arg0)),
4092 TREE_OPERAND (arg0, 1))));
4093 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4094 return fold (build (TREE_CODE (arg0), type,
4095 fold (build1 (CONJ_EXPR, type,
4096 TREE_OPERAND (arg0, 0))),
4097 fold (build1 (CONJ_EXPR,
4098 type, TREE_OPERAND (arg0, 1)))));
4099 else if (TREE_CODE (arg0) == CONJ_EXPR)
4100 return TREE_OPERAND (arg0, 0);
4106 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4107 ~ TREE_INT_CST_HIGH (arg0));
4108 TREE_TYPE (t) = type;
4109 force_fit_type (t, 0);
4110 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4111 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4113 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4114 return TREE_OPERAND (arg0, 0);
4118 /* A + (-B) -> A - B */
4119 if (TREE_CODE (arg1) == NEGATE_EXPR)
4120 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4121 else if (! FLOAT_TYPE_P (type))
4123 if (integer_zerop (arg1))
4124 return non_lvalue (convert (type, arg0));
4126 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4127 with a constant, and the two constants have no bits in common,
4128 we should treat this as a BIT_IOR_EXPR since this may produce more
4130 if (TREE_CODE (arg0) == BIT_AND_EXPR
4131 && TREE_CODE (arg1) == BIT_AND_EXPR
4132 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4133 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4134 && integer_zerop (const_binop (BIT_AND_EXPR,
4135 TREE_OPERAND (arg0, 1),
4136 TREE_OPERAND (arg1, 1), 0)))
4138 code = BIT_IOR_EXPR;
4142 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4143 about the case where C is a constant, just try one of the
4144 four possibilities. */
4146 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4147 && operand_equal_p (TREE_OPERAND (arg0, 1),
4148 TREE_OPERAND (arg1, 1), 0))
4149 return fold (build (MULT_EXPR, type,
4150 fold (build (PLUS_EXPR, type,
4151 TREE_OPERAND (arg0, 0),
4152 TREE_OPERAND (arg1, 0))),
4153 TREE_OPERAND (arg0, 1)));
4155 /* In IEEE floating point, x+0 may not equal x. */
4156 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4158 && real_zerop (arg1))
4159 return non_lvalue (convert (type, arg0));
4161 /* In most languages, can't associate operations on floats
4162 through parentheses. Rather than remember where the parentheses
4163 were, we don't associate floats at all. It shouldn't matter much.
4164 However, associating multiplications is only very slightly
4165 inaccurate, so do that if -ffast-math is specified. */
4166 if (FLOAT_TYPE_P (type)
4167 && ! (flag_fast_math && code == MULT_EXPR))
4170 /* The varsign == -1 cases happen only for addition and subtraction.
4171 It says that the arg that was split was really CON minus VAR.
4172 The rest of the code applies to all associative operations. */
4178 if (split_tree (arg0, code, &var, &con, &varsign))
4182 /* EXPR is (CON-VAR) +- ARG1. */
4183 /* If it is + and VAR==ARG1, return just CONST. */
4184 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4185 return convert (TREE_TYPE (t), con);
4187 /* If ARG0 is a constant, don't change things around;
4188 instead keep all the constant computations together. */
4190 if (TREE_CONSTANT (arg0))
4193 /* Otherwise return (CON +- ARG1) - VAR. */
4194 t = build (MINUS_EXPR, type,
4195 fold (build (code, type, con, arg1)), var);
4199 /* EXPR is (VAR+CON) +- ARG1. */
4200 /* If it is - and VAR==ARG1, return just CONST. */
4201 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4202 return convert (TREE_TYPE (t), con);
4204 /* If ARG0 is a constant, don't change things around;
4205 instead keep all the constant computations together. */
4207 if (TREE_CONSTANT (arg0))
4210 /* Otherwise return VAR +- (ARG1 +- CON). */
4211 tem = fold (build (code, type, arg1, con));
4212 t = build (code, type, var, tem);
4214 if (integer_zerop (tem)
4215 && (code == PLUS_EXPR || code == MINUS_EXPR))
4216 return convert (type, var);
4217 /* If we have x +/- (c - d) [c an explicit integer]
4218 change it to x -/+ (d - c) since if d is relocatable
4219 then the latter can be a single immediate insn
4220 and the former cannot. */
4221 if (TREE_CODE (tem) == MINUS_EXPR
4222 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4224 tree tem1 = TREE_OPERAND (tem, 1);
4225 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4226 TREE_OPERAND (tem, 0) = tem1;
4228 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4234 if (split_tree (arg1, code, &var, &con, &varsign))
4236 if (TREE_CONSTANT (arg1))
4241 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4243 /* EXPR is ARG0 +- (CON +- VAR). */
4244 if (TREE_CODE (t) == MINUS_EXPR
4245 && operand_equal_p (var, arg0, 0))
4247 /* If VAR and ARG0 cancel, return just CON or -CON. */
4248 if (code == PLUS_EXPR)
4249 return convert (TREE_TYPE (t), con);
4250 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4251 convert (TREE_TYPE (t), con)));
4254 t = build (TREE_CODE (t), type,
4255 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4257 if (integer_zerop (TREE_OPERAND (t, 0))
4258 && TREE_CODE (t) == PLUS_EXPR)
4259 return convert (TREE_TYPE (t), var);
4264 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4265 if (TREE_CODE (arg1) == REAL_CST)
4267 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4269 t1 = const_binop (code, arg0, arg1, 0);
4270 if (t1 != NULL_TREE)
4272 /* The return value should always have
4273 the same type as the original expression. */
4274 if (TREE_TYPE (t1) != TREE_TYPE (t))
4275 t1 = convert (TREE_TYPE (t), t1);
4282 if (! FLOAT_TYPE_P (type))
4284 if (! wins && integer_zerop (arg0))
4285 return build1 (NEGATE_EXPR, type, arg1);
4286 if (integer_zerop (arg1))
4287 return non_lvalue (convert (type, arg0));
4289 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4290 about the case where C is a constant, just try one of the
4291 four possibilities. */
4293 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4294 && operand_equal_p (TREE_OPERAND (arg0, 1),
4295 TREE_OPERAND (arg1, 1), 0))
4296 return fold (build (MULT_EXPR, type,
4297 fold (build (MINUS_EXPR, type,
4298 TREE_OPERAND (arg0, 0),
4299 TREE_OPERAND (arg1, 0))),
4300 TREE_OPERAND (arg0, 1)));
4302 /* Convert A - (-B) to A + B. */
4303 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4304 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4306 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4309 /* Except with IEEE floating point, 0-x equals -x. */
4310 if (! wins && real_zerop (arg0))
4311 return build1 (NEGATE_EXPR, type, arg1);
4312 /* Except with IEEE floating point, x-0 equals x. */
4313 if (real_zerop (arg1))
4314 return non_lvalue (convert (type, arg0));
4317 /* Fold &x - &x. This can happen from &x.foo - &x.
4318 This is unsafe for certain floats even in non-IEEE formats.
4319 In IEEE, it is unsafe because it does wrong for NaNs.
4320 Also note that operand_equal_p is always false if an operand
4323 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4324 && operand_equal_p (arg0, arg1, 0))
4325 return convert (type, integer_zero_node);
4330 if (! FLOAT_TYPE_P (type))
4332 if (integer_zerop (arg1))
4333 return omit_one_operand (type, arg1, arg0);
4334 if (integer_onep (arg1))
4335 return non_lvalue (convert (type, arg0));
4337 /* ((A / C) * C) is A if the division is an
4338 EXACT_DIV_EXPR. Since C is normally a constant,
4339 just check for one of the four possibilities. */
4341 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4342 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4343 return TREE_OPERAND (arg0, 0);
4345 /* (a * (1 << b)) is (a << b) */
4346 if (TREE_CODE (arg1) == LSHIFT_EXPR
4347 && integer_onep (TREE_OPERAND (arg1, 0)))
4348 return fold (build (LSHIFT_EXPR, type, arg0,
4349 TREE_OPERAND (arg1, 1)));
4350 if (TREE_CODE (arg0) == LSHIFT_EXPR
4351 && integer_onep (TREE_OPERAND (arg0, 0)))
4352 return fold (build (LSHIFT_EXPR, type, arg1,
4353 TREE_OPERAND (arg0, 1)));
4357 /* x*0 is 0, except for IEEE floating point. */
4358 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4360 && real_zerop (arg1))
4361 return omit_one_operand (type, arg1, arg0);
4362 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4363 However, ANSI says we can drop signals,
4364 so we can do this anyway. */
4365 if (real_onep (arg1))
4366 return non_lvalue (convert (type, arg0));
4368 if (! wins && real_twop (arg1))
4370 tree arg = save_expr (arg0);
4371 return build (PLUS_EXPR, type, arg, arg);
4379 register enum tree_code code0, code1;
4381 if (integer_all_onesp (arg1))
4382 return omit_one_operand (type, arg1, arg0);
4383 if (integer_zerop (arg1))
4384 return non_lvalue (convert (type, arg0));
4385 t1 = distribute_bit_expr (code, type, arg0, arg1);
4386 if (t1 != NULL_TREE)
4389 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4390 is a rotate of A by C1 bits. */
4391 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4392 is a rotate of A by B bits. */
4394 code0 = TREE_CODE (arg0);
4395 code1 = TREE_CODE (arg1);
4396 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4397 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4398 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4399 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4401 register tree tree01, tree11;
4402 register enum tree_code code01, code11;
4404 tree01 = TREE_OPERAND (arg0, 1);
4405 tree11 = TREE_OPERAND (arg1, 1);
4406 code01 = TREE_CODE (tree01);
4407 code11 = TREE_CODE (tree11);
4408 if (code01 == INTEGER_CST
4409 && code11 == INTEGER_CST
4410 && TREE_INT_CST_HIGH (tree01) == 0
4411 && TREE_INT_CST_HIGH (tree11) == 0
4412 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4413 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4414 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4415 code0 == LSHIFT_EXPR ? tree01 : tree11);
4416 else if (code11 == MINUS_EXPR
4417 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4418 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4419 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4420 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4421 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4422 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4423 type, TREE_OPERAND (arg0, 0), tree01);
4424 else if (code01 == MINUS_EXPR
4425 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4426 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4427 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4428 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4429 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4430 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4431 type, TREE_OPERAND (arg0, 0), tree11);
4438 if (integer_zerop (arg1))
4439 return non_lvalue (convert (type, arg0));
4440 if (integer_all_onesp (arg1))
4441 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4446 if (integer_all_onesp (arg1))
4447 return non_lvalue (convert (type, arg0));
4448 if (integer_zerop (arg1))
4449 return omit_one_operand (type, arg1, arg0);
4450 t1 = distribute_bit_expr (code, type, arg0, arg1);
4451 if (t1 != NULL_TREE)
4453 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4454 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4455 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4457 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4458 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4459 && (~TREE_INT_CST_LOW (arg0)
4460 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4461 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4463 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4464 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4466 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4467 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4468 && (~TREE_INT_CST_LOW (arg1)
4469 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4470 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4474 case BIT_ANDTC_EXPR:
4475 if (integer_all_onesp (arg0))
4476 return non_lvalue (convert (type, arg1));
4477 if (integer_zerop (arg0))
4478 return omit_one_operand (type, arg0, arg1);
4479 if (TREE_CODE (arg1) == INTEGER_CST)
4481 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4482 code = BIT_AND_EXPR;
4488 /* In most cases, do nothing with a divide by zero. */
4489 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4490 #ifndef REAL_INFINITY
4491 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4494 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4496 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4497 However, ANSI says we can drop signals, so we can do this anyway. */
4498 if (real_onep (arg1))
4499 return non_lvalue (convert (type, arg0));
4501 /* If ARG1 is a constant, we can convert this to a multiply by the
4502 reciprocal. This does not have the same rounding properties,
4503 so only do this if -ffast-math. We can actually always safely
4504 do it if ARG1 is a power of two, but it's hard to tell if it is
4505 or not in a portable manner. */
4506 if (TREE_CODE (arg1) == REAL_CST)
4509 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4511 return fold (build (MULT_EXPR, type, arg0, tem));
4512 /* Find the reciprocal if optimizing and the result is exact. */
4516 r = TREE_REAL_CST (arg1);
4517 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4519 tem = build_real (type, r);
4520 return fold (build (MULT_EXPR, type, arg0, tem));
4526 case TRUNC_DIV_EXPR:
4527 case ROUND_DIV_EXPR:
4528 case FLOOR_DIV_EXPR:
4530 case EXACT_DIV_EXPR:
4531 if (integer_onep (arg1))
4532 return non_lvalue (convert (type, arg0));
4533 if (integer_zerop (arg1))
4536 /* If we have ((a / C1) / C2) where both division are the same type, try
4537 to simplify. First see if C1 * C2 overflows or not. */
4538 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4539 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4543 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4544 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4546 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4547 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4549 /* If no overflow, divide by C1*C2. */
4550 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4554 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4555 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4556 expressions, which often appear in the offsets or sizes of
4557 objects with a varying size. Only deal with positive divisors
4558 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4560 Look for NOPs and SAVE_EXPRs inside. */
4562 if (TREE_CODE (arg1) == INTEGER_CST
4563 && tree_int_cst_sgn (arg1) >= 0)
4565 int have_save_expr = 0;
4566 tree c2 = integer_zero_node;
4569 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4570 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4574 if (TREE_CODE (xarg0) == PLUS_EXPR
4575 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4576 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4577 else if (TREE_CODE (xarg0) == MINUS_EXPR
4578 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4579 /* If we are doing this computation unsigned, the negate
4581 && ! TREE_UNSIGNED (type))
4583 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4584 xarg0 = TREE_OPERAND (xarg0, 0);
4587 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4588 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4592 if (TREE_CODE (xarg0) == MULT_EXPR
4593 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4594 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4595 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4596 TREE_OPERAND (xarg0, 1), arg1, 1))
4597 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4598 TREE_OPERAND (xarg0, 1), 1)))
4599 && (tree_int_cst_sgn (c2) >= 0
4600 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4603 tree outer_div = integer_one_node;
4604 tree c1 = TREE_OPERAND (xarg0, 1);
4607 /* If C3 > C1, set them equal and do a divide by
4608 C3/C1 at the end of the operation. */
4609 if (tree_int_cst_lt (c1, c3))
4610 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4612 /* The result is A * (C1/C3) + (C2/C3). */
4613 t = fold (build (PLUS_EXPR, type,
4614 fold (build (MULT_EXPR, type,
4615 TREE_OPERAND (xarg0, 0),
4616 const_binop (code, c1, c3, 1))),
4617 const_binop (code, c2, c3, 1)));
4619 if (! integer_onep (outer_div))
4620 t = fold (build (code, type, t, convert (type, outer_div)));
4632 case FLOOR_MOD_EXPR:
4633 case ROUND_MOD_EXPR:
4634 case TRUNC_MOD_EXPR:
4635 if (integer_onep (arg1))
4636 return omit_one_operand (type, integer_zero_node, arg0);
4637 if (integer_zerop (arg1))
4640 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4641 where C1 % C3 == 0. Handle similarly to the division case,
4642 but don't bother with SAVE_EXPRs. */
4644 if (TREE_CODE (arg1) == INTEGER_CST
4645 && ! integer_zerop (arg1))
4647 tree c2 = integer_zero_node;
4650 if (TREE_CODE (xarg0) == PLUS_EXPR
4651 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4652 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4653 else if (TREE_CODE (xarg0) == MINUS_EXPR
4654 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4655 && ! TREE_UNSIGNED (type))
4657 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4658 xarg0 = TREE_OPERAND (xarg0, 0);
4663 if (TREE_CODE (xarg0) == MULT_EXPR
4664 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4665 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4666 TREE_OPERAND (xarg0, 1),
4668 && tree_int_cst_sgn (c2) >= 0)
4669 /* The result is (C2%C3). */
4670 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4671 TREE_OPERAND (xarg0, 0));
4680 if (integer_zerop (arg1))
4681 return non_lvalue (convert (type, arg0));
4682 /* Since negative shift count is not well-defined,
4683 don't try to compute it in the compiler. */
4684 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4686 /* Rewrite an LROTATE_EXPR by a constant into an
4687 RROTATE_EXPR by a new constant. */
4688 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4690 TREE_SET_CODE (t, RROTATE_EXPR);
4691 code = RROTATE_EXPR;
4692 TREE_OPERAND (t, 1) = arg1
4695 convert (TREE_TYPE (arg1),
4696 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4698 if (tree_int_cst_sgn (arg1) < 0)
4702 /* If we have a rotate of a bit operation with the rotate count and
4703 the second operand of the bit operation both constant,
4704 permute the two operations. */
4705 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4706 && (TREE_CODE (arg0) == BIT_AND_EXPR
4707 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4708 || TREE_CODE (arg0) == BIT_IOR_EXPR
4709 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4710 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4711 return fold (build (TREE_CODE (arg0), type,
4712 fold (build (code, type,
4713 TREE_OPERAND (arg0, 0), arg1)),
4714 fold (build (code, type,
4715 TREE_OPERAND (arg0, 1), arg1))));
4717 /* Two consecutive rotates adding up to the width of the mode can
4719 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4720 && TREE_CODE (arg0) == RROTATE_EXPR
4721 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4722 && TREE_INT_CST_HIGH (arg1) == 0
4723 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4724 && ((TREE_INT_CST_LOW (arg1)
4725 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4726 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4727 return TREE_OPERAND (arg0, 0);
4732 if (operand_equal_p (arg0, arg1, 0))
4734 if (INTEGRAL_TYPE_P (type)
4735 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4736 return omit_one_operand (type, arg1, arg0);
4740 if (operand_equal_p (arg0, arg1, 0))
4742 if (INTEGRAL_TYPE_P (type)
4743 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4744 return omit_one_operand (type, arg1, arg0);
4747 case TRUTH_NOT_EXPR:
4748 /* Note that the operand of this must be an int
4749 and its values must be 0 or 1.
4750 ("true" is a fixed value perhaps depending on the language,
4751 but we don't handle values other than 1 correctly yet.) */
4752 tem = invert_truthvalue (arg0);
4753 /* Avoid infinite recursion. */
4754 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4756 return convert (type, tem);
4758 case TRUTH_ANDIF_EXPR:
4759 /* Note that the operands of this must be ints
4760 and their values must be 0 or 1.
4761 ("true" is a fixed value perhaps depending on the language.) */
4762 /* If first arg is constant zero, return it. */
4763 if (integer_zerop (arg0))
4765 case TRUTH_AND_EXPR:
4766 /* If either arg is constant true, drop it. */
4767 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4768 return non_lvalue (arg1);
4769 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4770 return non_lvalue (arg0);
4771 /* If second arg is constant zero, result is zero, but first arg
4772 must be evaluated. */
4773 if (integer_zerop (arg1))
4774 return omit_one_operand (type, arg1, arg0);
4775 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4776 case will be handled here. */
4777 if (integer_zerop (arg0))
4778 return omit_one_operand (type, arg0, arg1);
4781 /* We only do these simplifications if we are optimizing. */
4785 /* Check for things like (A || B) && (A || C). We can convert this
4786 to A || (B && C). Note that either operator can be any of the four
4787 truth and/or operations and the transformation will still be
4788 valid. Also note that we only care about order for the
4789 ANDIF and ORIF operators. */
4790 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4791 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4792 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4793 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4794 || TREE_CODE (arg0) == TRUTH_OR_EXPR))
4796 tree a00 = TREE_OPERAND (arg0, 0);
4797 tree a01 = TREE_OPERAND (arg0, 1);
4798 tree a10 = TREE_OPERAND (arg1, 0);
4799 tree a11 = TREE_OPERAND (arg1, 1);
4800 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
4801 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
4802 && (code == TRUTH_AND_EXPR
4803 || code == TRUTH_OR_EXPR));
4805 if (operand_equal_p (a00, a10, 0))
4806 return fold (build (TREE_CODE (arg0), type, a00,
4807 fold (build (code, type, a01, a11))));
4808 else if (commutative && operand_equal_p (a00, a11, 0))
4809 return fold (build (TREE_CODE (arg0), type, a00,
4810 fold (build (code, type, a01, a10))));
4811 else if (commutative && operand_equal_p (a01, a10, 0))
4812 return fold (build (TREE_CODE (arg0), type, a01,
4813 fold (build (code, type, a00, a11))));
4815 /* This case if tricky because we must either have commutative
4816 operators or else A10 must not have side-effects. */
4818 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
4819 && operand_equal_p (a01, a11, 0))
4820 return fold (build (TREE_CODE (arg0), type,
4821 fold (build (code, type, a00, a10)),
4825 /* See if we can build a range comparison. */
4826 if (0 != (tem = fold_range_test (t)))
4829 /* Check for the possibility of merging component references. If our
4830 lhs is another similar operation, try to merge its rhs with our
4831 rhs. Then try to merge our lhs and rhs. */
4832 if (TREE_CODE (arg0) == code
4833 && 0 != (tem = fold_truthop (code, type,
4834 TREE_OPERAND (arg0, 1), arg1)))
4835 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
4837 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
4842 case TRUTH_ORIF_EXPR:
4843 /* Note that the operands of this must be ints
4844 and their values must be 0 or true.
4845 ("true" is a fixed value perhaps depending on the language.) */
4846 /* If first arg is constant true, return it. */
4847 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4850 /* If either arg is constant zero, drop it. */
4851 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
4852 return non_lvalue (arg1);
4853 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
4854 return non_lvalue (arg0);
4855 /* If second arg is constant true, result is true, but we must
4856 evaluate first arg. */
4857 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4858 return omit_one_operand (type, arg1, arg0);
4859 /* Likewise for first arg, but note this only occurs here for
4861 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4862 return omit_one_operand (type, arg0, arg1);
4865 case TRUTH_XOR_EXPR:
4866 /* If either arg is constant zero, drop it. */
4867 if (integer_zerop (arg0))
4868 return non_lvalue (arg1);
4869 if (integer_zerop (arg1))
4870 return non_lvalue (arg0);
4871 /* If either arg is constant true, this is a logical inversion. */
4872 if (integer_onep (arg0))
4873 return non_lvalue (invert_truthvalue (arg1));
4874 if (integer_onep (arg1))
4875 return non_lvalue (invert_truthvalue (arg0));
4884 /* If one arg is a constant integer, put it last. */
4885 if (TREE_CODE (arg0) == INTEGER_CST
4886 && TREE_CODE (arg1) != INTEGER_CST)
4888 TREE_OPERAND (t, 0) = arg1;
4889 TREE_OPERAND (t, 1) = arg0;
4890 arg0 = TREE_OPERAND (t, 0);
4891 arg1 = TREE_OPERAND (t, 1);
4892 code = swap_tree_comparison (code);
4893 TREE_SET_CODE (t, code);
4896 /* Convert foo++ == CONST into ++foo == CONST + INCR.
4897 First, see if one arg is constant; find the constant arg
4898 and the other one. */
4900 tree constop = 0, varop;
4901 int constopnum = -1;
4903 if (TREE_CONSTANT (arg1))
4904 constopnum = 1, constop = arg1, varop = arg0;
4905 if (TREE_CONSTANT (arg0))
4906 constopnum = 0, constop = arg0, varop = arg1;
4908 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
4910 /* This optimization is invalid for ordered comparisons
4911 if CONST+INCR overflows or if foo+incr might overflow.
4912 This optimization is invalid for floating point due to rounding.
4913 For pointer types we assume overflow doesn't happen. */
4914 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4915 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4916 && (code == EQ_EXPR || code == NE_EXPR)))
4919 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
4920 constop, TREE_OPERAND (varop, 1)));
4921 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
4923 /* If VAROP is a reference to a bitfield, we must mask
4924 the constant by the width of the field. */
4925 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
4926 && DECL_BIT_FIELD(TREE_OPERAND
4927 (TREE_OPERAND (varop, 0), 1)))
4930 = TREE_INT_CST_LOW (DECL_SIZE
4932 (TREE_OPERAND (varop, 0), 1)));
4934 newconst = fold (build (BIT_AND_EXPR,
4935 TREE_TYPE (varop), newconst,
4936 convert (TREE_TYPE (varop),
4937 build_int_2 (size, 0))));
4941 t = build (code, type, TREE_OPERAND (t, 0),
4942 TREE_OPERAND (t, 1));
4943 TREE_OPERAND (t, constopnum) = newconst;
4947 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
4949 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4950 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4951 && (code == EQ_EXPR || code == NE_EXPR)))
4954 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
4955 constop, TREE_OPERAND (varop, 1)));
4956 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
4958 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
4959 && DECL_BIT_FIELD(TREE_OPERAND
4960 (TREE_OPERAND (varop, 0), 1)))
4963 = TREE_INT_CST_LOW (DECL_SIZE
4965 (TREE_OPERAND (varop, 0), 1)));
4967 newconst = fold (build (BIT_AND_EXPR,
4968 TREE_TYPE (varop), newconst,
4969 convert (TREE_TYPE (varop),
4970 build_int_2 (size, 0))));
4974 t = build (code, type, TREE_OPERAND (t, 0),
4975 TREE_OPERAND (t, 1));
4976 TREE_OPERAND (t, constopnum) = newconst;
4982 /* Change X >= CST to X > (CST - 1) if CST is positive. */
4983 if (TREE_CODE (arg1) == INTEGER_CST
4984 && TREE_CODE (arg0) != INTEGER_CST
4985 && tree_int_cst_sgn (arg1) > 0)
4987 switch (TREE_CODE (t))
4991 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4992 t = build (code, type, TREE_OPERAND (t, 0), arg1);
4997 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4998 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5003 /* If this is an EQ or NE comparison with zero and ARG0 is
5004 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5005 two operations, but the latter can be done in one less insn
5006 one machine that have only two-operand insns or on which a
5007 constant cannot be the first operand. */
5008 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5009 && TREE_CODE (arg0) == BIT_AND_EXPR)
5011 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5012 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5014 fold (build (code, type,
5015 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5017 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5018 TREE_OPERAND (arg0, 1),
5019 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5020 convert (TREE_TYPE (arg0),
5023 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5024 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5026 fold (build (code, type,
5027 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5029 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5030 TREE_OPERAND (arg0, 0),
5031 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5032 convert (TREE_TYPE (arg0),
5037 /* If this is an NE or EQ comparison of zero against the result of a
5038 signed MOD operation whose second operand is a power of 2, make
5039 the MOD operation unsigned since it is simpler and equivalent. */
5040 if ((code == NE_EXPR || code == EQ_EXPR)
5041 && integer_zerop (arg1)
5042 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5043 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5044 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5045 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5046 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5047 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5049 tree newtype = unsigned_type (TREE_TYPE (arg0));
5050 tree newmod = build (TREE_CODE (arg0), newtype,
5051 convert (newtype, TREE_OPERAND (arg0, 0)),
5052 convert (newtype, TREE_OPERAND (arg0, 1)));
5054 return build (code, type, newmod, convert (newtype, arg1));
5057 /* If this is an NE comparison of zero with an AND of one, remove the
5058 comparison since the AND will give the correct value. */
5059 if (code == NE_EXPR && integer_zerop (arg1)
5060 && TREE_CODE (arg0) == BIT_AND_EXPR
5061 && integer_onep (TREE_OPERAND (arg0, 1)))
5062 return convert (type, arg0);
5064 /* If we have (A & C) == C where C is a power of 2, convert this into
5065 (A & C) != 0. Similarly for NE_EXPR. */
5066 if ((code == EQ_EXPR || code == NE_EXPR)
5067 && TREE_CODE (arg0) == BIT_AND_EXPR
5068 && integer_pow2p (TREE_OPERAND (arg0, 1))
5069 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5070 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5071 arg0, integer_zero_node);
5073 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5074 and similarly for >= into !=. */
5075 if ((code == LT_EXPR || code == GE_EXPR)
5076 && TREE_UNSIGNED (TREE_TYPE (arg0))
5077 && TREE_CODE (arg1) == LSHIFT_EXPR
5078 && integer_onep (TREE_OPERAND (arg1, 0)))
5079 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5080 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5081 TREE_OPERAND (arg1, 1)),
5082 convert (TREE_TYPE (arg0), integer_zero_node));
5084 else if ((code == LT_EXPR || code == GE_EXPR)
5085 && TREE_UNSIGNED (TREE_TYPE (arg0))
5086 && (TREE_CODE (arg1) == NOP_EXPR
5087 || TREE_CODE (arg1) == CONVERT_EXPR)
5088 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5089 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5091 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5092 convert (TREE_TYPE (arg0),
5093 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5094 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5095 convert (TREE_TYPE (arg0), integer_zero_node));
5097 /* Simplify comparison of something with itself. (For IEEE
5098 floating-point, we can only do some of these simplifications.) */
5099 if (operand_equal_p (arg0, arg1, 0))
5106 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5108 if (type == integer_type_node)
5109 return integer_one_node;
5111 t = build_int_2 (1, 0);
5112 TREE_TYPE (t) = type;
5116 TREE_SET_CODE (t, code);
5120 /* For NE, we can only do this simplification if integer. */
5121 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5123 /* ... fall through ... */
5126 if (type == integer_type_node)
5127 return integer_zero_node;
5129 t = build_int_2 (0, 0);
5130 TREE_TYPE (t) = type;
5135 /* An unsigned comparison against 0 can be simplified. */
5136 if (integer_zerop (arg1)
5137 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5138 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5139 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5141 switch (TREE_CODE (t))
5145 TREE_SET_CODE (t, NE_EXPR);
5149 TREE_SET_CODE (t, EQ_EXPR);
5152 return omit_one_operand (type,
5153 convert (type, integer_one_node),
5156 return omit_one_operand (type,
5157 convert (type, integer_zero_node),
5162 /* If we are comparing an expression that just has comparisons
5163 of two integer values, arithmetic expressions of those comparisons,
5164 and constants, we can simplify it. There are only three cases
5165 to check: the two values can either be equal, the first can be
5166 greater, or the second can be greater. Fold the expression for
5167 those three values. Since each value must be 0 or 1, we have
5168 eight possibilities, each of which corresponds to the constant 0
5169 or 1 or one of the six possible comparisons.
5171 This handles common cases like (a > b) == 0 but also handles
5172 expressions like ((x > y) - (y > x)) > 0, which supposedly
5173 occur in macroized code. */
5175 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5177 tree cval1 = 0, cval2 = 0;
5180 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5181 /* Don't handle degenerate cases here; they should already
5182 have been handled anyway. */
5183 && cval1 != 0 && cval2 != 0
5184 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5185 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5186 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5187 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5188 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5190 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5191 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5193 /* We can't just pass T to eval_subst in case cval1 or cval2
5194 was the same as ARG1. */
5197 = fold (build (code, type,
5198 eval_subst (arg0, cval1, maxval, cval2, minval),
5201 = fold (build (code, type,
5202 eval_subst (arg0, cval1, maxval, cval2, maxval),
5205 = fold (build (code, type,
5206 eval_subst (arg0, cval1, minval, cval2, maxval),
5209 /* All three of these results should be 0 or 1. Confirm they
5210 are. Then use those values to select the proper code
5213 if ((integer_zerop (high_result)
5214 || integer_onep (high_result))
5215 && (integer_zerop (equal_result)
5216 || integer_onep (equal_result))
5217 && (integer_zerop (low_result)
5218 || integer_onep (low_result)))
5220 /* Make a 3-bit mask with the high-order bit being the
5221 value for `>', the next for '=', and the low for '<'. */
5222 switch ((integer_onep (high_result) * 4)
5223 + (integer_onep (equal_result) * 2)
5224 + integer_onep (low_result))
5228 return omit_one_operand (type, integer_zero_node, arg0);
5249 return omit_one_operand (type, integer_one_node, arg0);
5252 t = build (code, type, cval1, cval2);
5254 return save_expr (t);
5261 /* If this is a comparison of a field, we may be able to simplify it. */
5262 if ((TREE_CODE (arg0) == COMPONENT_REF
5263 || TREE_CODE (arg0) == BIT_FIELD_REF)
5264 && (code == EQ_EXPR || code == NE_EXPR)
5265 /* Handle the constant case even without -O
5266 to make sure the warnings are given. */
5267 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5269 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5273 /* If this is a comparison of complex values and either or both
5274 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5275 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5276 may prevent needless evaluations. */
5277 if ((code == EQ_EXPR || code == NE_EXPR)
5278 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5279 && (TREE_CODE (arg0) == COMPLEX_EXPR
5280 || TREE_CODE (arg1) == COMPLEX_EXPR))
5282 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5283 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5284 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5285 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5286 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5288 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5291 fold (build (code, type, real0, real1)),
5292 fold (build (code, type, imag0, imag1))));
5295 /* From here on, the only cases we handle are when the result is
5296 known to be a constant.
5298 To compute GT, swap the arguments and do LT.
5299 To compute GE, do LT and invert the result.
5300 To compute LE, swap the arguments, do LT and invert the result.
5301 To compute NE, do EQ and invert the result.
5303 Therefore, the code below must handle only EQ and LT. */
5305 if (code == LE_EXPR || code == GT_EXPR)
5307 tem = arg0, arg0 = arg1, arg1 = tem;
5308 code = swap_tree_comparison (code);
5311 /* Note that it is safe to invert for real values here because we
5312 will check below in the one case that it matters. */
5315 if (code == NE_EXPR || code == GE_EXPR)
5318 code = invert_tree_comparison (code);
5321 /* Compute a result for LT or EQ if args permit;
5322 otherwise return T. */
5323 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5325 if (code == EQ_EXPR)
5326 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5327 == TREE_INT_CST_LOW (arg1))
5328 && (TREE_INT_CST_HIGH (arg0)
5329 == TREE_INT_CST_HIGH (arg1)),
5332 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5333 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5334 : INT_CST_LT (arg0, arg1)),
5338 #if 0 /* This is no longer useful, but breaks some real code. */
5339 /* Assume a nonexplicit constant cannot equal an explicit one,
5340 since such code would be undefined anyway.
5341 Exception: on sysvr4, using #pragma weak,
5342 a label can come out as 0. */
5343 else if (TREE_CODE (arg1) == INTEGER_CST
5344 && !integer_zerop (arg1)
5345 && TREE_CONSTANT (arg0)
5346 && TREE_CODE (arg0) == ADDR_EXPR
5348 t1 = build_int_2 (0, 0);
5350 /* Two real constants can be compared explicitly. */
5351 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5353 /* If either operand is a NaN, the result is false with two
5354 exceptions: First, an NE_EXPR is true on NaNs, but that case
5355 is already handled correctly since we will be inverting the
5356 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5357 or a GE_EXPR into a LT_EXPR, we must return true so that it
5358 will be inverted into false. */
5360 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5361 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5362 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5364 else if (code == EQ_EXPR)
5365 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5366 TREE_REAL_CST (arg1)),
5369 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5370 TREE_REAL_CST (arg1)),
5374 if (t1 == NULL_TREE)
5378 TREE_INT_CST_LOW (t1) ^= 1;
5380 TREE_TYPE (t1) = type;
5384 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5385 so all simple results must be passed through pedantic_non_lvalue. */
5386 if (TREE_CODE (arg0) == INTEGER_CST)
5387 return pedantic_non_lvalue
5388 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5389 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5390 return pedantic_omit_one_operand (type, arg1, arg0);
5392 /* If the second operand is zero, invert the comparison and swap
5393 the second and third operands. Likewise if the second operand
5394 is constant and the third is not or if the third operand is
5395 equivalent to the first operand of the comparison. */
5397 if (integer_zerop (arg1)
5398 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5399 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5400 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5401 TREE_OPERAND (t, 2),
5402 TREE_OPERAND (arg0, 1))))
5404 /* See if this can be inverted. If it can't, possibly because
5405 it was a floating-point inequality comparison, don't do
5407 tem = invert_truthvalue (arg0);
5409 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5411 t = build (code, type, tem,
5412 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5414 arg1 = TREE_OPERAND (t, 2);
5419 /* If we have A op B ? A : C, we may be able to convert this to a
5420 simpler expression, depending on the operation and the values
5421 of B and C. IEEE floating point prevents this though,
5422 because A or B might be -0.0 or a NaN. */
5424 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5425 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5426 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5428 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5429 arg1, TREE_OPERAND (arg0, 1)))
5431 tree arg2 = TREE_OPERAND (t, 2);
5432 enum tree_code comp_code = TREE_CODE (arg0);
5436 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5437 depending on the comparison operation. */
5438 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5439 ? real_zerop (TREE_OPERAND (arg0, 1))
5440 : integer_zerop (TREE_OPERAND (arg0, 1)))
5441 && TREE_CODE (arg2) == NEGATE_EXPR
5442 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5446 return pedantic_non_lvalue
5447 (fold (build1 (NEGATE_EXPR, type, arg1)));
5449 return pedantic_non_lvalue (convert (type, arg1));
5452 return pedantic_non_lvalue
5453 (convert (type, fold (build1 (ABS_EXPR,
5454 TREE_TYPE (arg1), arg1))));
5457 return pedantic_non_lvalue
5458 (fold (build1 (NEGATE_EXPR, type,
5460 fold (build1 (ABS_EXPR,
5465 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5468 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5470 if (comp_code == NE_EXPR)
5471 return pedantic_non_lvalue (convert (type, arg1));
5472 else if (comp_code == EQ_EXPR)
5473 return pedantic_non_lvalue (convert (type, integer_zero_node));
5476 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5477 or max (A, B), depending on the operation. */
5479 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5480 arg2, TREE_OPERAND (arg0, 0)))
5482 tree comp_op0 = TREE_OPERAND (arg0, 0);
5483 tree comp_op1 = TREE_OPERAND (arg0, 1);
5484 tree comp_type = TREE_TYPE (comp_op0);
5489 return pedantic_non_lvalue (convert (type, arg2));
5491 return pedantic_non_lvalue (convert (type, arg1));
5494 return pedantic_non_lvalue
5495 (convert (type, (fold (build (MIN_EXPR, comp_type,
5496 comp_op0, comp_op1)))));
5499 return pedantic_non_lvalue
5500 (convert (type, fold (build (MAX_EXPR, comp_type,
5501 comp_op0, comp_op1))));
5505 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5506 we might still be able to simplify this. For example,
5507 if C1 is one less or one more than C2, this might have started
5508 out as a MIN or MAX and been transformed by this function.
5509 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5511 if (INTEGRAL_TYPE_P (type)
5512 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5513 && TREE_CODE (arg2) == INTEGER_CST)
5517 /* We can replace A with C1 in this case. */
5518 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5519 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5520 TREE_OPERAND (t, 2));
5524 /* If C1 is C2 + 1, this is min(A, C2). */
5525 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5526 && operand_equal_p (TREE_OPERAND (arg0, 1),
5527 const_binop (PLUS_EXPR, arg2,
5528 integer_one_node, 0), 1))
5529 return pedantic_non_lvalue
5530 (fold (build (MIN_EXPR, type, arg1, arg2)));
5534 /* If C1 is C2 - 1, this is min(A, C2). */
5535 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5536 && operand_equal_p (TREE_OPERAND (arg0, 1),
5537 const_binop (MINUS_EXPR, arg2,
5538 integer_one_node, 0), 1))
5539 return pedantic_non_lvalue
5540 (fold (build (MIN_EXPR, type, arg1, arg2)));
5544 /* If C1 is C2 - 1, this is max(A, C2). */
5545 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5546 && operand_equal_p (TREE_OPERAND (arg0, 1),
5547 const_binop (MINUS_EXPR, arg2,
5548 integer_one_node, 0), 1))
5549 return pedantic_non_lvalue
5550 (fold (build (MAX_EXPR, type, arg1, arg2)));
5554 /* If C1 is C2 + 1, this is max(A, C2). */
5555 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5556 && operand_equal_p (TREE_OPERAND (arg0, 1),
5557 const_binop (PLUS_EXPR, arg2,
5558 integer_one_node, 0), 1))
5559 return pedantic_non_lvalue
5560 (fold (build (MAX_EXPR, type, arg1, arg2)));
5565 /* If the second operand is simpler than the third, swap them
5566 since that produces better jump optimization results. */
5567 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5568 || TREE_CODE (arg1) == SAVE_EXPR)
5569 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5570 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5571 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5573 /* See if this can be inverted. If it can't, possibly because
5574 it was a floating-point inequality comparison, don't do
5576 tem = invert_truthvalue (arg0);
5578 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5580 t = build (code, type, tem,
5581 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5583 arg1 = TREE_OPERAND (t, 2);
5588 /* Convert A ? 1 : 0 to simply A. */
5589 if (integer_onep (TREE_OPERAND (t, 1))
5590 && integer_zerop (TREE_OPERAND (t, 2))
5591 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5592 call to fold will try to move the conversion inside
5593 a COND, which will recurse. In that case, the COND_EXPR
5594 is probably the best choice, so leave it alone. */
5595 && type == TREE_TYPE (arg0))
5596 return pedantic_non_lvalue (arg0);
5598 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5599 operation is simply A & 2. */
5601 if (integer_zerop (TREE_OPERAND (t, 2))
5602 && TREE_CODE (arg0) == NE_EXPR
5603 && integer_zerop (TREE_OPERAND (arg0, 1))
5604 && integer_pow2p (arg1)
5605 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5606 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5608 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5613 /* When pedantic, a compound expression can be neither an lvalue
5614 nor an integer constant expression. */
5615 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5617 /* Don't let (0, 0) be null pointer constant. */
5618 if (integer_zerop (arg1))
5619 return non_lvalue (arg1);
5624 return build_complex (type, arg0, arg1);
5628 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5630 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5631 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5632 TREE_OPERAND (arg0, 1));
5633 else if (TREE_CODE (arg0) == COMPLEX_CST)
5634 return TREE_REALPART (arg0);
5635 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5636 return fold (build (TREE_CODE (arg0), type,
5637 fold (build1 (REALPART_EXPR, type,
5638 TREE_OPERAND (arg0, 0))),
5639 fold (build1 (REALPART_EXPR,
5640 type, TREE_OPERAND (arg0, 1)))));
5644 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5645 return convert (type, integer_zero_node);
5646 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5647 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5648 TREE_OPERAND (arg0, 0));
5649 else if (TREE_CODE (arg0) == COMPLEX_CST)
5650 return TREE_IMAGPART (arg0);
5651 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5652 return fold (build (TREE_CODE (arg0), type,
5653 fold (build1 (IMAGPART_EXPR, type,
5654 TREE_OPERAND (arg0, 0))),
5655 fold (build1 (IMAGPART_EXPR, type,
5656 TREE_OPERAND (arg0, 1)))));
5659 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5661 case CLEANUP_POINT_EXPR:
5662 if (! TREE_SIDE_EFFECTS (arg0))
5663 return TREE_OPERAND (t, 0);
5666 enum tree_code code0 = TREE_CODE (arg0);
5667 int kind0 = TREE_CODE_CLASS (code0);
5668 tree arg00 = TREE_OPERAND (arg0, 0);
5671 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5672 return fold (build1 (code0, type,
5673 fold (build1 (CLEANUP_POINT_EXPR,
5674 TREE_TYPE (arg00), arg00))));
5676 if (kind0 == '<' || kind0 == '2'
5677 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5678 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5679 || code0 == TRUTH_XOR_EXPR)
5681 arg01 = TREE_OPERAND (arg0, 1);
5683 if (! TREE_SIDE_EFFECTS (arg00))
5684 return fold (build (code0, type, arg00,
5685 fold (build1 (CLEANUP_POINT_EXPR,
5686 TREE_TYPE (arg01), arg01))));
5688 if (! TREE_SIDE_EFFECTS (arg01))
5689 return fold (build (code0, type,
5690 fold (build1 (CLEANUP_POINT_EXPR,
5691 TREE_TYPE (arg00), arg00)),
5700 } /* switch (code) */