1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 88, 92-96, 1997 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /*@@ This file should be rewritten to use an arbitrary precision
22 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
23 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
24 @@ The routines that translate from the ap rep should
25 @@ warn if precision et. al. is lost.
26 @@ This would also make life easier when this technology is used
27 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int, size_binop
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type takes a constant and prior overflow indicator, and
43 forces the value to fit the type. It returns an overflow indicator. */
51 /* Handle floating overflow for `const_binop'. */
52 static jmp_buf float_error;
54 static void encode PROTO((HOST_WIDE_INT *,
55 HOST_WIDE_INT, HOST_WIDE_INT));
56 static void decode PROTO((HOST_WIDE_INT *,
57 HOST_WIDE_INT *, HOST_WIDE_INT *));
58 int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
59 HOST_WIDE_INT, HOST_WIDE_INT,
60 HOST_WIDE_INT, HOST_WIDE_INT *,
61 HOST_WIDE_INT *, HOST_WIDE_INT *,
63 static int split_tree PROTO((tree, enum tree_code, tree *,
65 static tree const_binop PROTO((enum tree_code, tree, tree, int));
66 static tree fold_convert PROTO((tree, tree));
67 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
68 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
69 static int truth_value_p PROTO((enum tree_code));
70 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
71 static int twoval_comparison_p PROTO((tree, tree *, tree *, int *));
72 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
73 static tree omit_one_operand PROTO((tree, tree, tree));
74 static tree pedantic_omit_one_operand PROTO((tree, tree, tree));
75 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
76 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
77 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
79 static tree decode_field_reference PROTO((tree, int *, int *,
80 enum machine_mode *, int *,
81 int *, tree *, tree *));
82 static int all_ones_mask_p PROTO((tree, int));
83 static int simple_operand_p PROTO((tree));
84 static tree range_binop PROTO((enum tree_code, tree, tree, int,
86 static tree make_range PROTO((tree, int *, tree *, tree *));
87 static tree build_range_check PROTO((tree, tree, int, tree, tree));
88 static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree,
90 static tree fold_range_test PROTO((tree));
91 static tree unextend PROTO((tree, int, int, tree));
92 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
93 static tree strip_compound_expr PROTO((tree, tree));
94 static int multiple_of_p PROTO((tree, tree, tree));
100 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
101 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
102 Then this yields nonzero if overflow occurred during the addition.
103 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
104 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
105 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
107 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
108 We do that by representing the two-word integer in 4 words, with only
109 HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */
112 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1))
113 #define HIGHPART(x) \
114 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2)
115 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2)
117 /* Unpack a two-word integer into 4 words.
118 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
119 WORDS points to the array of HOST_WIDE_INTs. */
122 encode (words, low, hi)
123 HOST_WIDE_INT *words;
124 HOST_WIDE_INT low, hi;
126 words[0] = LOWPART (low);
127 words[1] = HIGHPART (low);
128 words[2] = LOWPART (hi);
129 words[3] = HIGHPART (hi);
132 /* Pack an array of 4 words into a two-word integer.
133 WORDS points to the array of words.
134 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
137 decode (words, low, hi)
138 HOST_WIDE_INT *words;
139 HOST_WIDE_INT *low, *hi;
141 *low = words[0] | words[1] * BASE;
142 *hi = words[2] | words[3] * BASE;
145 /* Make the integer constant T valid for its type
146 by setting to 0 or 1 all the bits in the constant
147 that don't belong in the type.
148 Yield 1 if a signed overflow occurs, 0 otherwise.
149 If OVERFLOW is nonzero, a signed overflow has already occurred
150 in calculating T, so propagate it.
152 Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
156 force_fit_type (t, overflow)
160 HOST_WIDE_INT low, high;
163 if (TREE_CODE (t) == REAL_CST)
165 #ifdef CHECK_FLOAT_VALUE
166 CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
172 else if (TREE_CODE (t) != INTEGER_CST)
175 low = TREE_INT_CST_LOW (t);
176 high = TREE_INT_CST_HIGH (t);
178 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
181 prec = TYPE_PRECISION (TREE_TYPE (t));
183 /* First clear all bits that are beyond the type's precision. */
185 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
187 else if (prec > HOST_BITS_PER_WIDE_INT)
189 TREE_INT_CST_HIGH (t)
190 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
194 TREE_INT_CST_HIGH (t) = 0;
195 if (prec < HOST_BITS_PER_WIDE_INT)
196 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
199 /* Unsigned types do not suffer sign extension or overflow. */
200 if (TREE_UNSIGNED (TREE_TYPE (t)))
203 /* If the value's sign bit is set, extend the sign. */
204 if (prec != 2 * HOST_BITS_PER_WIDE_INT
205 && (prec > HOST_BITS_PER_WIDE_INT
206 ? (TREE_INT_CST_HIGH (t)
207 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
208 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
210 /* Value is negative:
211 set to 1 all the bits that are outside this type's precision. */
212 if (prec > HOST_BITS_PER_WIDE_INT)
214 TREE_INT_CST_HIGH (t)
215 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
219 TREE_INT_CST_HIGH (t) = -1;
220 if (prec < HOST_BITS_PER_WIDE_INT)
221 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
225 /* Yield nonzero if signed overflow occurred. */
227 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
231 /* Add two doubleword integers with doubleword result.
232 Each argument is given as two `HOST_WIDE_INT' pieces.
233 One argument is L1 and H1; the other, L2 and H2.
234 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
237 add_double (l1, h1, l2, h2, lv, hv)
238 HOST_WIDE_INT l1, h1, l2, h2;
239 HOST_WIDE_INT *lv, *hv;
244 h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1);
248 return overflow_sum_sign (h1, h2, h);
251 /* Negate a doubleword integer with doubleword result.
252 Return nonzero if the operation overflows, assuming it's signed.
253 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
254 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
257 neg_double (l1, h1, lv, hv)
258 HOST_WIDE_INT l1, h1;
259 HOST_WIDE_INT *lv, *hv;
265 return (*hv & h1) < 0;
275 /* Multiply two doubleword integers with doubleword result.
276 Return nonzero if the operation overflows, assuming it's signed.
277 Each argument is given as two `HOST_WIDE_INT' pieces.
278 One argument is L1 and H1; the other, L2 and H2.
279 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
282 mul_double (l1, h1, l2, h2, lv, hv)
283 HOST_WIDE_INT l1, h1, l2, h2;
284 HOST_WIDE_INT *lv, *hv;
286 HOST_WIDE_INT arg1[4];
287 HOST_WIDE_INT arg2[4];
288 HOST_WIDE_INT prod[4 * 2];
289 register unsigned HOST_WIDE_INT carry;
290 register int i, j, k;
291 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
293 encode (arg1, l1, h1);
294 encode (arg2, l2, h2);
296 bzero ((char *) prod, sizeof prod);
298 for (i = 0; i < 4; i++)
301 for (j = 0; j < 4; j++)
304 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
305 carry += arg1[i] * arg2[j];
306 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
308 prod[k] = LOWPART (carry);
309 carry = HIGHPART (carry);
314 decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
316 /* Check for overflow by calculating the top half of the answer in full;
317 it should agree with the low half's sign bit. */
318 decode (prod+4, &toplow, &tophigh);
321 neg_double (l2, h2, &neglow, &neghigh);
322 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
326 neg_double (l1, h1, &neglow, &neghigh);
327 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
329 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
332 /* Shift the doubleword integer in L1, H1 left by COUNT places
333 keeping only PREC bits of result.
334 Shift right if COUNT is negative.
335 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
336 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
339 lshift_double (l1, h1, count, prec, lv, hv, arith)
340 HOST_WIDE_INT l1, h1, count;
342 HOST_WIDE_INT *lv, *hv;
347 rshift_double (l1, h1, - count, prec, lv, hv, arith);
351 #ifdef SHIFT_COUNT_TRUNCATED
352 if (SHIFT_COUNT_TRUNCATED)
356 if (count >= HOST_BITS_PER_WIDE_INT)
358 *hv = (unsigned HOST_WIDE_INT) l1 << count - HOST_BITS_PER_WIDE_INT;
363 *hv = (((unsigned HOST_WIDE_INT) h1 << count)
364 | ((unsigned HOST_WIDE_INT) l1 >> HOST_BITS_PER_WIDE_INT - count - 1 >> 1));
365 *lv = (unsigned HOST_WIDE_INT) l1 << count;
369 /* Shift the doubleword integer in L1, H1 right by COUNT places
370 keeping only PREC bits of result. COUNT must be positive.
371 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
372 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
375 rshift_double (l1, h1, count, prec, lv, hv, arith)
376 HOST_WIDE_INT l1, h1, count;
378 HOST_WIDE_INT *lv, *hv;
381 unsigned HOST_WIDE_INT signmask;
383 ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
386 #ifdef SHIFT_COUNT_TRUNCATED
387 if (SHIFT_COUNT_TRUNCATED)
391 if (count >= HOST_BITS_PER_WIDE_INT)
394 *lv = ((signmask << 2 * HOST_BITS_PER_WIDE_INT - count - 1 << 1)
395 | ((unsigned HOST_WIDE_INT) h1 >> count - HOST_BITS_PER_WIDE_INT));
399 *lv = (((unsigned HOST_WIDE_INT) l1 >> count)
400 | ((unsigned HOST_WIDE_INT) h1 << HOST_BITS_PER_WIDE_INT - count - 1 << 1));
401 *hv = ((signmask << HOST_BITS_PER_WIDE_INT - count)
402 | ((unsigned HOST_WIDE_INT) h1 >> count));
406 /* Rotate the doubleword integer in L1, H1 left by COUNT places
407 keeping only PREC bits of result.
408 Rotate right if COUNT is negative.
409 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
412 lrotate_double (l1, h1, count, prec, lv, hv)
413 HOST_WIDE_INT l1, h1, count;
415 HOST_WIDE_INT *lv, *hv;
417 HOST_WIDE_INT s1l, s1h, s2l, s2h;
423 lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
424 rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
429 /* Rotate the doubleword integer in L1, H1 left by COUNT places
430 keeping only PREC bits of result. COUNT must be positive.
431 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
434 rrotate_double (l1, h1, count, prec, lv, hv)
435 HOST_WIDE_INT l1, h1, count;
437 HOST_WIDE_INT *lv, *hv;
439 HOST_WIDE_INT s1l, s1h, s2l, s2h;
445 rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
446 lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
451 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
452 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
453 CODE is a tree code for a kind of division, one of
454 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
456 It controls how the quotient is rounded to a integer.
457 Return nonzero if the operation overflows.
458 UNS nonzero says do unsigned division. */
461 div_and_round_double (code, uns,
462 lnum_orig, hnum_orig, lden_orig, hden_orig,
463 lquo, hquo, lrem, hrem)
466 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
467 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
468 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
471 HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
472 HOST_WIDE_INT den[4], quo[4];
474 unsigned HOST_WIDE_INT work;
475 register unsigned HOST_WIDE_INT carry = 0;
476 HOST_WIDE_INT lnum = lnum_orig;
477 HOST_WIDE_INT hnum = hnum_orig;
478 HOST_WIDE_INT lden = lden_orig;
479 HOST_WIDE_INT hden = hden_orig;
482 if ((hden == 0) && (lden == 0))
485 /* calculate quotient sign and convert operands to unsigned. */
491 /* (minimum integer) / (-1) is the only overflow case. */
492 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
498 neg_double (lden, hden, &lden, &hden);
502 if (hnum == 0 && hden == 0)
503 { /* single precision */
505 /* This unsigned division rounds toward zero. */
506 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
511 { /* trivial case: dividend < divisor */
512 /* hden != 0 already checked. */
519 bzero ((char *) quo, sizeof quo);
521 bzero ((char *) num, sizeof num); /* to zero 9th element */
522 bzero ((char *) den, sizeof den);
524 encode (num, lnum, hnum);
525 encode (den, lden, hden);
527 /* Special code for when the divisor < BASE. */
528 if (hden == 0 && lden < BASE)
530 /* hnum != 0 already checked. */
531 for (i = 4 - 1; i >= 0; i--)
533 work = num[i] + carry * BASE;
534 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
535 carry = work % (unsigned HOST_WIDE_INT) lden;
540 /* Full double precision division,
541 with thanks to Don Knuth's "Seminumerical Algorithms". */
542 int num_hi_sig, den_hi_sig;
543 unsigned HOST_WIDE_INT quo_est, scale;
545 /* Find the highest non-zero divisor digit. */
546 for (i = 4 - 1; ; i--)
552 /* Insure that the first digit of the divisor is at least BASE/2.
553 This is required by the quotient digit estimation algorithm. */
555 scale = BASE / (den[den_hi_sig] + 1);
556 if (scale > 1) { /* scale divisor and dividend */
558 for (i = 0; i <= 4 - 1; i++) {
559 work = (num[i] * scale) + carry;
560 num[i] = LOWPART (work);
561 carry = HIGHPART (work);
564 for (i = 0; i <= 4 - 1; i++) {
565 work = (den[i] * scale) + carry;
566 den[i] = LOWPART (work);
567 carry = HIGHPART (work);
568 if (den[i] != 0) den_hi_sig = i;
575 for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) {
576 /* guess the next quotient digit, quo_est, by dividing the first
577 two remaining dividend digits by the high order quotient digit.
578 quo_est is never low and is at most 2 high. */
579 unsigned HOST_WIDE_INT tmp;
581 num_hi_sig = i + den_hi_sig + 1;
582 work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
583 if (num[num_hi_sig] != den[den_hi_sig])
584 quo_est = work / den[den_hi_sig];
588 /* refine quo_est so it's usually correct, and at most one high. */
589 tmp = work - quo_est * den[den_hi_sig];
591 && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2]))
594 /* Try QUO_EST as the quotient digit, by multiplying the
595 divisor by QUO_EST and subtracting from the remaining dividend.
596 Keep in mind that QUO_EST is the I - 1st digit. */
599 for (j = 0; j <= den_hi_sig; j++)
601 work = quo_est * den[j] + carry;
602 carry = HIGHPART (work);
603 work = num[i + j] - LOWPART (work);
604 num[i + j] = LOWPART (work);
605 carry += HIGHPART (work) != 0;
608 /* if quo_est was high by one, then num[i] went negative and
609 we need to correct things. */
611 if (num[num_hi_sig] < carry)
614 carry = 0; /* add divisor back in */
615 for (j = 0; j <= den_hi_sig; j++)
617 work = num[i + j] + den[j] + carry;
618 carry = HIGHPART (work);
619 num[i + j] = LOWPART (work);
621 num [num_hi_sig] += carry;
624 /* store the quotient digit. */
629 decode (quo, lquo, hquo);
632 /* if result is negative, make it so. */
634 neg_double (*lquo, *hquo, lquo, hquo);
636 /* compute trial remainder: rem = num - (quo * den) */
637 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
638 neg_double (*lrem, *hrem, lrem, hrem);
639 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
644 case TRUNC_MOD_EXPR: /* round toward zero */
645 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
649 case FLOOR_MOD_EXPR: /* round toward negative infinity */
650 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
653 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
656 else return overflow;
660 case CEIL_MOD_EXPR: /* round toward positive infinity */
661 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
663 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
666 else return overflow;
670 case ROUND_MOD_EXPR: /* round to closest integer */
672 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
673 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
675 /* get absolute values */
676 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
677 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
679 /* if (2 * abs (lrem) >= abs (lden)) */
680 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
681 labs_rem, habs_rem, <wice, &htwice);
682 if (((unsigned HOST_WIDE_INT) habs_den
683 < (unsigned HOST_WIDE_INT) htwice)
684 || (((unsigned HOST_WIDE_INT) habs_den
685 == (unsigned HOST_WIDE_INT) htwice)
686 && ((HOST_WIDE_INT unsigned) labs_den
687 < (unsigned HOST_WIDE_INT) ltwice)))
691 add_double (*lquo, *hquo,
692 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
695 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
698 else return overflow;
706 /* compute true remainder: rem = num - (quo * den) */
707 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
708 neg_double (*lrem, *hrem, lrem, hrem);
709 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
713 #ifndef REAL_ARITHMETIC
714 /* Effectively truncate a real value to represent the nearest possible value
715 in a narrower mode. The result is actually represented in the same data
716 type as the argument, but its value is usually different.
718 A trap may occur during the FP operations and it is the responsibility
719 of the calling function to have a handler established. */
722 real_value_truncate (mode, arg)
723 enum machine_mode mode;
726 return REAL_VALUE_TRUNCATE (mode, arg);
729 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
731 /* Check for infinity in an IEEE double precision number. */
737 /* The IEEE 64-bit double format. */
742 unsigned exponent : 11;
743 unsigned mantissa1 : 20;
748 unsigned mantissa1 : 20;
749 unsigned exponent : 11;
755 if (u.big_endian.sign == 1)
758 return (u.big_endian.exponent == 2047
759 && u.big_endian.mantissa1 == 0
760 && u.big_endian.mantissa2 == 0);
765 return (u.little_endian.exponent == 2047
766 && u.little_endian.mantissa1 == 0
767 && u.little_endian.mantissa2 == 0);
771 /* Check whether an IEEE double precision number is a NaN. */
777 /* The IEEE 64-bit double format. */
782 unsigned exponent : 11;
783 unsigned mantissa1 : 20;
788 unsigned mantissa1 : 20;
789 unsigned exponent : 11;
795 if (u.big_endian.sign == 1)
798 return (u.big_endian.exponent == 2047
799 && (u.big_endian.mantissa1 != 0
800 || u.big_endian.mantissa2 != 0));
805 return (u.little_endian.exponent == 2047
806 && (u.little_endian.mantissa1 != 0
807 || u.little_endian.mantissa2 != 0));
811 /* Check for a negative IEEE double precision number. */
817 /* The IEEE 64-bit double format. */
822 unsigned exponent : 11;
823 unsigned mantissa1 : 20;
828 unsigned mantissa1 : 20;
829 unsigned exponent : 11;
835 if (u.big_endian.sign == 1)
838 return u.big_endian.sign;
843 return u.little_endian.sign;
846 #else /* Target not IEEE */
848 /* Let's assume other float formats don't have infinity.
849 (This can be overridden by redefining REAL_VALUE_ISINF.) */
857 /* Let's assume other float formats don't have NaNs.
858 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
866 /* Let's assume other float formats don't have minus zero.
867 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
874 #endif /* Target not IEEE */
876 /* Try to change R into its exact multiplicative inverse in machine mode
877 MODE. Return nonzero function value if successful. */
880 exact_real_inverse (mode, r)
881 enum machine_mode mode;
891 /* Usually disable if bounds checks are not reliable. */
892 if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
895 /* Set array index to the less significant bits in the unions, depending
896 on the endian-ness of the host doubles.
897 Disable if insufficient information on the data structure. */
898 #if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
901 #if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT
904 #if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
907 #define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
912 if (setjmp (float_error))
914 /* Don't do the optimization if there was an arithmetic error. */
916 set_float_handler (NULL_PTR);
919 set_float_handler (float_error);
921 /* Domain check the argument. */
927 if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
931 /* Compute the reciprocal and check for numerical exactness.
932 It is unnecessary to check all the significand bits to determine
933 whether X is a power of 2. If X is not, then it is impossible for
934 the bottom half significand of both X and 1/X to be all zero bits.
935 Hence we ignore the data structure of the top half and examine only
936 the low order bits of the two significands. */
938 if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
941 /* Truncate to the required mode and range-check the result. */
942 y.d = REAL_VALUE_TRUNCATE (mode, t.d);
943 #ifdef CHECK_FLOAT_VALUE
945 if (CHECK_FLOAT_VALUE (mode, y.d, i))
949 /* Fail if truncation changed the value. */
950 if (y.d != t.d || y.d == 0.0)
954 if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
958 /* Output the reciprocal and return success flag. */
959 set_float_handler (NULL_PTR);
963 #endif /* no REAL_ARITHMETIC */
965 /* Split a tree IN into a constant and a variable part
966 that could be combined with CODE to make IN.
967 CODE must be a commutative arithmetic operation.
968 Store the constant part into *CONP and the variable in &VARP.
969 Return 1 if this was done; zero means the tree IN did not decompose
972 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
973 Therefore, we must tell the caller whether the variable part
974 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
975 The value stored is the coefficient for the variable term.
976 The constant term we return should always be added;
977 we negate it if necessary. */
980 split_tree (in, code, varp, conp, varsignp)
986 register tree outtype = TREE_TYPE (in);
990 /* Strip any conversions that don't change the machine mode. */
991 while ((TREE_CODE (in) == NOP_EXPR
992 || TREE_CODE (in) == CONVERT_EXPR)
993 && (TYPE_MODE (TREE_TYPE (in))
994 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
995 in = TREE_OPERAND (in, 0);
997 if (TREE_CODE (in) == code
998 || (! FLOAT_TYPE_P (TREE_TYPE (in))
999 /* We can associate addition and subtraction together
1000 (even though the C standard doesn't say so)
1001 for integers because the value is not affected.
1002 For reals, the value might be affected, so we can't. */
1003 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
1004 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1006 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1007 if (code == INTEGER_CST)
1009 *conp = TREE_OPERAND (in, 0);
1010 *varp = TREE_OPERAND (in, 1);
1011 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1012 && TREE_TYPE (*varp) != outtype)
1013 *varp = convert (outtype, *varp);
1014 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1017 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1019 *conp = TREE_OPERAND (in, 1);
1020 *varp = TREE_OPERAND (in, 0);
1022 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1023 && TREE_TYPE (*varp) != outtype)
1024 *varp = convert (outtype, *varp);
1025 if (TREE_CODE (in) == MINUS_EXPR)
1027 /* If operation is subtraction and constant is second,
1028 must negate it to get an additive constant.
1029 And this cannot be done unless it is a manifest constant.
1030 It could also be the address of a static variable.
1031 We cannot negate that, so give up. */
1032 if (TREE_CODE (*conp) == INTEGER_CST)
1033 /* Subtracting from integer_zero_node loses for long long. */
1034 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1040 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1042 *conp = TREE_OPERAND (in, 0);
1043 *varp = TREE_OPERAND (in, 1);
1044 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1045 && TREE_TYPE (*varp) != outtype)
1046 *varp = convert (outtype, *varp);
1047 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1054 /* Combine two constants ARG1 and ARG2 under operation CODE
1055 to produce a new constant.
1056 We assume ARG1 and ARG2 have the same data type,
1057 or at least are the same kind of constant and the same machine mode.
1059 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1062 const_binop (code, arg1, arg2, notrunc)
1063 enum tree_code code;
1064 register tree arg1, arg2;
1067 STRIP_NOPS (arg1); STRIP_NOPS (arg2);
1069 if (TREE_CODE (arg1) == INTEGER_CST)
1071 register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1);
1072 register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1);
1073 HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2);
1074 HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2);
1075 HOST_WIDE_INT low, hi;
1076 HOST_WIDE_INT garbagel, garbageh;
1078 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1080 int no_overflow = 0;
1085 low = int1l | int2l, hi = int1h | int2h;
1089 low = int1l ^ int2l, hi = int1h ^ int2h;
1093 low = int1l & int2l, hi = int1h & int2h;
1096 case BIT_ANDTC_EXPR:
1097 low = int1l & ~int2l, hi = int1h & ~int2h;
1103 /* It's unclear from the C standard whether shifts can overflow.
1104 The following code ignores overflow; perhaps a C standard
1105 interpretation ruling is needed. */
1106 lshift_double (int1l, int1h, int2l,
1107 TYPE_PRECISION (TREE_TYPE (arg1)),
1116 lrotate_double (int1l, int1h, int2l,
1117 TYPE_PRECISION (TREE_TYPE (arg1)),
1122 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1126 neg_double (int2l, int2h, &low, &hi);
1127 add_double (int1l, int1h, low, hi, &low, &hi);
1128 overflow = overflow_sum_sign (hi, int2h, int1h);
1132 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1135 case TRUNC_DIV_EXPR:
1136 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1137 case EXACT_DIV_EXPR:
1138 /* This is a shortcut for a common special case. */
1139 if (int2h == 0 && int2l > 0
1140 && ! TREE_CONSTANT_OVERFLOW (arg1)
1141 && ! TREE_CONSTANT_OVERFLOW (arg2)
1142 && int1h == 0 && int1l >= 0)
1144 if (code == CEIL_DIV_EXPR)
1146 low = int1l / int2l, hi = 0;
1150 /* ... fall through ... */
1152 case ROUND_DIV_EXPR:
1153 if (int2h == 0 && int2l == 1)
1155 low = int1l, hi = int1h;
1158 if (int1l == int2l && int1h == int2h
1159 && ! (int1l == 0 && int1h == 0))
1164 overflow = div_and_round_double (code, uns,
1165 int1l, int1h, int2l, int2h,
1166 &low, &hi, &garbagel, &garbageh);
1169 case TRUNC_MOD_EXPR:
1170 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1171 /* This is a shortcut for a common special case. */
1172 if (int2h == 0 && int2l > 0
1173 && ! TREE_CONSTANT_OVERFLOW (arg1)
1174 && ! TREE_CONSTANT_OVERFLOW (arg2)
1175 && int1h == 0 && int1l >= 0)
1177 if (code == CEIL_MOD_EXPR)
1179 low = int1l % int2l, hi = 0;
1183 /* ... fall through ... */
1185 case ROUND_MOD_EXPR:
1186 overflow = div_and_round_double (code, uns,
1187 int1l, int1h, int2l, int2h,
1188 &garbagel, &garbageh, &low, &hi);
1195 low = (((unsigned HOST_WIDE_INT) int1h
1196 < (unsigned HOST_WIDE_INT) int2h)
1197 || (((unsigned HOST_WIDE_INT) int1h
1198 == (unsigned HOST_WIDE_INT) int2h)
1199 && ((unsigned HOST_WIDE_INT) int1l
1200 < (unsigned HOST_WIDE_INT) int2l)));
1204 low = ((int1h < int2h)
1205 || ((int1h == int2h)
1206 && ((unsigned HOST_WIDE_INT) int1l
1207 < (unsigned HOST_WIDE_INT) int2l)));
1209 if (low == (code == MIN_EXPR))
1210 low = int1l, hi = int1h;
1212 low = int2l, hi = int2h;
1219 if (TREE_TYPE (arg1) == sizetype && hi == 0
1220 && low >= 0 && low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype))
1222 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
1226 t = build_int_2 (low, hi);
1227 TREE_TYPE (t) = TREE_TYPE (arg1);
1231 = ((notrunc ? !uns && overflow
1232 : force_fit_type (t, overflow && !uns) && ! no_overflow)
1233 | TREE_OVERFLOW (arg1)
1234 | TREE_OVERFLOW (arg2));
1235 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1236 | TREE_CONSTANT_OVERFLOW (arg1)
1237 | TREE_CONSTANT_OVERFLOW (arg2));
1240 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1241 if (TREE_CODE (arg1) == REAL_CST)
1246 REAL_VALUE_TYPE value;
1249 d1 = TREE_REAL_CST (arg1);
1250 d2 = TREE_REAL_CST (arg2);
1252 /* If either operand is a NaN, just return it. Otherwise, set up
1253 for floating-point trap; we return an overflow. */
1254 if (REAL_VALUE_ISNAN (d1))
1256 else if (REAL_VALUE_ISNAN (d2))
1258 else if (setjmp (float_error))
1260 t = copy_node (arg1);
1265 set_float_handler (float_error);
1267 #ifdef REAL_ARITHMETIC
1268 REAL_ARITHMETIC (value, code, d1, d2);
1285 #ifndef REAL_INFINITY
1294 value = MIN (d1, d2);
1298 value = MAX (d1, d2);
1304 #endif /* no REAL_ARITHMETIC */
1305 t = build_real (TREE_TYPE (arg1),
1306 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1308 set_float_handler (NULL_PTR);
1311 = (force_fit_type (t, overflow)
1312 | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
1313 TREE_CONSTANT_OVERFLOW (t)
1315 | TREE_CONSTANT_OVERFLOW (arg1)
1316 | TREE_CONSTANT_OVERFLOW (arg2);
1319 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1320 if (TREE_CODE (arg1) == COMPLEX_CST)
1322 register tree type = TREE_TYPE (arg1);
1323 register tree r1 = TREE_REALPART (arg1);
1324 register tree i1 = TREE_IMAGPART (arg1);
1325 register tree r2 = TREE_REALPART (arg2);
1326 register tree i2 = TREE_IMAGPART (arg2);
1332 t = build_complex (type,
1333 const_binop (PLUS_EXPR, r1, r2, notrunc),
1334 const_binop (PLUS_EXPR, i1, i2, notrunc));
1338 t = build_complex (type,
1339 const_binop (MINUS_EXPR, r1, r2, notrunc),
1340 const_binop (MINUS_EXPR, i1, i2, notrunc));
1344 t = build_complex (type,
1345 const_binop (MINUS_EXPR,
1346 const_binop (MULT_EXPR,
1348 const_binop (MULT_EXPR,
1351 const_binop (PLUS_EXPR,
1352 const_binop (MULT_EXPR,
1354 const_binop (MULT_EXPR,
1361 register tree magsquared
1362 = const_binop (PLUS_EXPR,
1363 const_binop (MULT_EXPR, r2, r2, notrunc),
1364 const_binop (MULT_EXPR, i2, i2, notrunc),
1367 t = build_complex (type,
1369 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1370 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1371 const_binop (PLUS_EXPR,
1372 const_binop (MULT_EXPR, r1, r2,
1374 const_binop (MULT_EXPR, i1, i2,
1377 magsquared, notrunc),
1379 (INTEGRAL_TYPE_P (TREE_TYPE (r1))
1380 ? TRUNC_DIV_EXPR : RDIV_EXPR,
1381 const_binop (MINUS_EXPR,
1382 const_binop (MULT_EXPR, i1, r2,
1384 const_binop (MULT_EXPR, r1, i2,
1387 magsquared, notrunc));
1399 /* Return an INTEGER_CST with value V and type from `sizetype'. */
1403 unsigned HOST_WIDE_INT number;
1406 /* Type-size nodes already made for small sizes. */
1407 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1409 if (number < 2*HOST_BITS_PER_WIDE_INT + 1
1410 && size_table[number] != 0)
1411 return size_table[number];
1412 if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
1414 push_obstacks_nochange ();
1415 /* Make this a permanent node. */
1416 end_temporary_allocation ();
1417 t = build_int_2 (number, 0);
1418 TREE_TYPE (t) = sizetype;
1419 size_table[number] = t;
1424 t = build_int_2 (number, 0);
1425 TREE_TYPE (t) = sizetype;
1426 TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0);
1431 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1432 CODE is a tree code. Data type is taken from `sizetype',
1433 If the operands are constant, so is the result. */
1436 size_binop (code, arg0, arg1)
1437 enum tree_code code;
1440 /* Handle the special case of two integer constants faster. */
1441 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1443 /* And some specific cases even faster than that. */
1444 if (code == PLUS_EXPR && integer_zerop (arg0))
1446 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
1447 && integer_zerop (arg1))
1449 else if (code == MULT_EXPR && integer_onep (arg0))
1452 /* Handle general case of two integer constants. */
1453 return const_binop (code, arg0, arg1, 0);
1456 if (arg0 == error_mark_node || arg1 == error_mark_node)
1457 return error_mark_node;
1459 return fold (build (code, sizetype, arg0, arg1));
1462 /* Given T, a tree representing type conversion of ARG1, a constant,
1463 return a constant tree representing the result of conversion. */
1466 fold_convert (t, arg1)
1470 register tree type = TREE_TYPE (t);
1473 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1475 if (TREE_CODE (arg1) == INTEGER_CST)
1477 /* If we would build a constant wider than GCC supports,
1478 leave the conversion unfolded. */
1479 if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
1482 /* Given an integer constant, make new constant with new type,
1483 appropriately sign-extended or truncated. */
1484 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1485 TREE_INT_CST_HIGH (arg1));
1486 TREE_TYPE (t) = type;
1487 /* Indicate an overflow if (1) ARG1 already overflowed,
1488 or (2) force_fit_type indicates an overflow.
1489 Tell force_fit_type that an overflow has already occurred
1490 if ARG1 is a too-large unsigned value and T is signed. */
1492 = (TREE_OVERFLOW (arg1)
1493 | force_fit_type (t,
1494 (TREE_INT_CST_HIGH (arg1) < 0
1495 & (TREE_UNSIGNED (type)
1496 < TREE_UNSIGNED (TREE_TYPE (arg1))))));
1497 TREE_CONSTANT_OVERFLOW (t)
1498 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1500 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1501 else if (TREE_CODE (arg1) == REAL_CST)
1503 /* Don't initialize these, use assignments.
1504 Initialized local aggregates don't work on old compilers. */
1508 tree type1 = TREE_TYPE (arg1);
1510 x = TREE_REAL_CST (arg1);
1511 l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
1512 u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
1513 /* See if X will be in range after truncation towards 0.
1514 To compensate for truncation, move the bounds away from 0,
1515 but reject if X exactly equals the adjusted bounds. */
1516 #ifdef REAL_ARITHMETIC
1517 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1518 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1523 /* If X is a NaN, use zero instead and show we have an overflow.
1524 Otherwise, range check. */
1525 if (REAL_VALUE_ISNAN (x))
1526 overflow = 1, x = dconst0;
1527 else if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
1530 #ifndef REAL_ARITHMETIC
1532 HOST_WIDE_INT low, high;
1533 HOST_WIDE_INT half_word
1534 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1539 high = (HOST_WIDE_INT) (x / half_word / half_word);
1540 x -= (REAL_VALUE_TYPE) high * half_word * half_word;
1541 if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1543 low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
1544 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1547 low = (HOST_WIDE_INT) x;
1548 if (TREE_REAL_CST (arg1) < 0)
1549 neg_double (low, high, &low, &high);
1550 t = build_int_2 (low, high);
1554 HOST_WIDE_INT low, high;
1555 REAL_VALUE_TO_INT (&low, &high, x);
1556 t = build_int_2 (low, high);
1559 TREE_TYPE (t) = type;
1561 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1562 TREE_CONSTANT_OVERFLOW (t)
1563 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1565 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1566 TREE_TYPE (t) = type;
1568 else if (TREE_CODE (type) == REAL_TYPE)
1570 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1571 if (TREE_CODE (arg1) == INTEGER_CST)
1572 return build_real_from_int_cst (type, arg1);
1573 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1574 if (TREE_CODE (arg1) == REAL_CST)
1576 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
1579 TREE_TYPE (arg1) = type;
1582 else if (setjmp (float_error))
1585 t = copy_node (arg1);
1588 set_float_handler (float_error);
1590 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1591 TREE_REAL_CST (arg1)));
1592 set_float_handler (NULL_PTR);
1596 = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
1597 TREE_CONSTANT_OVERFLOW (t)
1598 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1602 TREE_CONSTANT (t) = 1;
1606 /* Return an expr equal to X but certainly not valid as an lvalue.
1607 Also make sure it is not valid as an null pointer constant. */
1615 /* These things are certainly not lvalues. */
1616 if (TREE_CODE (x) == NON_LVALUE_EXPR
1617 || TREE_CODE (x) == INTEGER_CST
1618 || TREE_CODE (x) == REAL_CST
1619 || TREE_CODE (x) == STRING_CST
1620 || TREE_CODE (x) == ADDR_EXPR)
1622 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1624 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1625 so convert_for_assignment won't strip it.
1626 This is so this 0 won't be treated as a null pointer constant. */
1627 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1628 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1634 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1635 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1639 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
1640 Zero means allow extended lvalues. */
1642 int pedantic_lvalues;
1644 /* When pedantic, return an expr equal to X but certainly not valid as a
1645 pedantic lvalue. Otherwise, return X. */
1648 pedantic_non_lvalue (x)
1651 if (pedantic_lvalues)
1652 return non_lvalue (x);
1657 /* Given a tree comparison code, return the code that is the logical inverse
1658 of the given code. It is not safe to do this for floating-point
1659 comparisons, except for NE_EXPR and EQ_EXPR. */
1661 static enum tree_code
1662 invert_tree_comparison (code)
1663 enum tree_code code;
1684 /* Similar, but return the comparison that results if the operands are
1685 swapped. This is safe for floating-point. */
1687 static enum tree_code
1688 swap_tree_comparison (code)
1689 enum tree_code code;
1709 /* Return nonzero if CODE is a tree code that represents a truth value. */
1712 truth_value_p (code)
1713 enum tree_code code;
1715 return (TREE_CODE_CLASS (code) == '<'
1716 || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
1717 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
1718 || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
1721 /* Return nonzero if two operands are necessarily equal.
1722 If ONLY_CONST is non-zero, only return non-zero for constants.
1723 This function tests whether the operands are indistinguishable;
1724 it does not test whether they are equal using C's == operation.
1725 The distinction is important for IEEE floating point, because
1726 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1727 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1730 operand_equal_p (arg0, arg1, only_const)
1734 /* If both types don't have the same signedness, then we can't consider
1735 them equal. We must check this before the STRIP_NOPS calls
1736 because they may change the signedness of the arguments. */
1737 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1743 if (TREE_CODE (arg0) != TREE_CODE (arg1)
1744 /* This is needed for conversions and for COMPONENT_REF.
1745 Might as well play it safe and always test this. */
1746 || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1749 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1750 We don't care about side effects in that case because the SAVE_EXPR
1751 takes care of that for us. In all other cases, two expressions are
1752 equal if they have no side effects. If we have two identical
1753 expressions with side effects that should be treated the same due
1754 to the only side effects being identical SAVE_EXPR's, that will
1755 be detected in the recursive calls below. */
1756 if (arg0 == arg1 && ! only_const
1757 && (TREE_CODE (arg0) == SAVE_EXPR
1758 || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
1761 /* Next handle constant cases, those for which we can return 1 even
1762 if ONLY_CONST is set. */
1763 if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
1764 switch (TREE_CODE (arg0))
1767 return (! TREE_CONSTANT_OVERFLOW (arg0)
1768 && ! TREE_CONSTANT_OVERFLOW (arg1)
1769 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1770 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
1773 return (! TREE_CONSTANT_OVERFLOW (arg0)
1774 && ! TREE_CONSTANT_OVERFLOW (arg1)
1775 && REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
1776 TREE_REAL_CST (arg1)));
1779 return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
1781 && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
1785 return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
1786 && ! strncmp (TREE_STRING_POINTER (arg0),
1787 TREE_STRING_POINTER (arg1),
1788 TREE_STRING_LENGTH (arg0)));
1791 return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
1798 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1801 /* Two conversions are equal only if signedness and modes match. */
1802 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1803 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1804 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1807 return operand_equal_p (TREE_OPERAND (arg0, 0),
1808 TREE_OPERAND (arg1, 0), 0);
1812 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
1813 && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
1817 /* For commutative ops, allow the other order. */
1818 return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
1819 || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
1820 || TREE_CODE (arg0) == BIT_IOR_EXPR
1821 || TREE_CODE (arg0) == BIT_XOR_EXPR
1822 || TREE_CODE (arg0) == BIT_AND_EXPR
1823 || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
1824 && operand_equal_p (TREE_OPERAND (arg0, 0),
1825 TREE_OPERAND (arg1, 1), 0)
1826 && operand_equal_p (TREE_OPERAND (arg0, 1),
1827 TREE_OPERAND (arg1, 0), 0));
1830 switch (TREE_CODE (arg0))
1833 return operand_equal_p (TREE_OPERAND (arg0, 0),
1834 TREE_OPERAND (arg1, 0), 0);
1838 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1839 TREE_OPERAND (arg1, 0), 0)
1840 && operand_equal_p (TREE_OPERAND (arg0, 1),
1841 TREE_OPERAND (arg1, 1), 0));
1844 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1845 TREE_OPERAND (arg1, 0), 0)
1846 && operand_equal_p (TREE_OPERAND (arg0, 1),
1847 TREE_OPERAND (arg1, 1), 0)
1848 && operand_equal_p (TREE_OPERAND (arg0, 2),
1849 TREE_OPERAND (arg1, 2), 0));
1857 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1858 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1860 When in doubt, return 0. */
1863 operand_equal_for_comparison_p (arg0, arg1, other)
1867 int unsignedp1, unsignedpo;
1868 tree primarg1, primother;
1869 unsigned correct_width;
1871 if (operand_equal_p (arg0, arg1, 0))
1874 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
1875 || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
1878 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1879 actual comparison operand, ARG0.
1881 First throw away any conversions to wider types
1882 already present in the operands. */
1884 primarg1 = get_narrower (arg1, &unsignedp1);
1885 primother = get_narrower (other, &unsignedpo);
1887 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1888 if (unsignedp1 == unsignedpo
1889 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1890 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1892 tree type = TREE_TYPE (arg0);
1894 /* Make sure shorter operand is extended the right way
1895 to match the longer operand. */
1896 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1897 TREE_TYPE (primarg1)),
1900 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1907 /* See if ARG is an expression that is either a comparison or is performing
1908 arithmetic on comparisons. The comparisons must only be comparing
1909 two different values, which will be stored in *CVAL1 and *CVAL2; if
1910 they are non-zero it means that some operands have already been found.
1911 No variables may be used anywhere else in the expression except in the
1912 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
1913 the expression and save_expr needs to be called with CVAL1 and CVAL2.
1915 If this is true, return 1. Otherwise, return zero. */
1918 twoval_comparison_p (arg, cval1, cval2, save_p)
1920 tree *cval1, *cval2;
1923 enum tree_code code = TREE_CODE (arg);
1924 char class = TREE_CODE_CLASS (code);
1926 /* We can handle some of the 'e' cases here. */
1927 if (class == 'e' && code == TRUTH_NOT_EXPR)
1929 else if (class == 'e'
1930 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1931 || code == COMPOUND_EXPR))
1934 /* ??? Disable this since the SAVE_EXPR might already be in use outside
1935 the expression. There may be no way to make this work, but it needs
1936 to be looked at again for 2.6. */
1938 else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)
1940 /* If we've already found a CVAL1 or CVAL2, this expression is
1941 two complex to handle. */
1942 if (*cval1 || *cval2)
1953 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
1956 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
1957 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1958 cval1, cval2, save_p));
1964 if (code == COND_EXPR)
1965 return (twoval_comparison_p (TREE_OPERAND (arg, 0),
1966 cval1, cval2, save_p)
1967 && twoval_comparison_p (TREE_OPERAND (arg, 1),
1968 cval1, cval2, save_p)
1969 && twoval_comparison_p (TREE_OPERAND (arg, 2),
1970 cval1, cval2, save_p));
1974 /* First see if we can handle the first operand, then the second. For
1975 the second operand, we know *CVAL1 can't be zero. It must be that
1976 one side of the comparison is each of the values; test for the
1977 case where this isn't true by failing if the two operands
1980 if (operand_equal_p (TREE_OPERAND (arg, 0),
1981 TREE_OPERAND (arg, 1), 0))
1985 *cval1 = TREE_OPERAND (arg, 0);
1986 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
1988 else if (*cval2 == 0)
1989 *cval2 = TREE_OPERAND (arg, 0);
1990 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
1995 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
1997 else if (*cval2 == 0)
1998 *cval2 = TREE_OPERAND (arg, 1);
1999 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
2010 /* ARG is a tree that is known to contain just arithmetic operations and
2011 comparisons. Evaluate the operations in the tree substituting NEW0 for
2012 any occurrence of OLD0 as an operand of a comparison and likewise for
2016 eval_subst (arg, old0, new0, old1, new1)
2018 tree old0, new0, old1, new1;
2020 tree type = TREE_TYPE (arg);
2021 enum tree_code code = TREE_CODE (arg);
2022 char class = TREE_CODE_CLASS (code);
2024 /* We can handle some of the 'e' cases here. */
2025 if (class == 'e' && code == TRUTH_NOT_EXPR)
2027 else if (class == 'e'
2028 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
2034 return fold (build1 (code, type,
2035 eval_subst (TREE_OPERAND (arg, 0),
2036 old0, new0, old1, new1)));
2039 return fold (build (code, type,
2040 eval_subst (TREE_OPERAND (arg, 0),
2041 old0, new0, old1, new1),
2042 eval_subst (TREE_OPERAND (arg, 1),
2043 old0, new0, old1, new1)));
2049 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2052 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2055 return fold (build (code, type,
2056 eval_subst (TREE_OPERAND (arg, 0),
2057 old0, new0, old1, new1),
2058 eval_subst (TREE_OPERAND (arg, 1),
2059 old0, new0, old1, new1),
2060 eval_subst (TREE_OPERAND (arg, 2),
2061 old0, new0, old1, new1)));
2066 tree arg0 = TREE_OPERAND (arg, 0);
2067 tree arg1 = TREE_OPERAND (arg, 1);
2069 /* We need to check both for exact equality and tree equality. The
2070 former will be true if the operand has a side-effect. In that
2071 case, we know the operand occurred exactly once. */
2073 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2075 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2078 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2080 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2083 return fold (build (code, type, arg0, arg1));
2090 /* Return a tree for the case when the result of an expression is RESULT
2091 converted to TYPE and OMITTED was previously an operand of the expression
2092 but is now not needed (e.g., we folded OMITTED * 0).
2094 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2095 the conversion of RESULT to TYPE. */
2098 omit_one_operand (type, result, omitted)
2099 tree type, result, omitted;
2101 tree t = convert (type, result);
2103 if (TREE_SIDE_EFFECTS (omitted))
2104 return build (COMPOUND_EXPR, type, omitted, t);
2106 return non_lvalue (t);
2109 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
2112 pedantic_omit_one_operand (type, result, omitted)
2113 tree type, result, omitted;
2115 tree t = convert (type, result);
2117 if (TREE_SIDE_EFFECTS (omitted))
2118 return build (COMPOUND_EXPR, type, omitted, t);
2120 return pedantic_non_lvalue (t);
2125 /* Return a simplified tree node for the truth-negation of ARG. This
2126 never alters ARG itself. We assume that ARG is an operation that
2127 returns a truth value (0 or 1). */
2130 invert_truthvalue (arg)
2133 tree type = TREE_TYPE (arg);
2134 enum tree_code code = TREE_CODE (arg);
2136 if (code == ERROR_MARK)
2139 /* If this is a comparison, we can simply invert it, except for
2140 floating-point non-equality comparisons, in which case we just
2141 enclose a TRUTH_NOT_EXPR around what we have. */
2143 if (TREE_CODE_CLASS (code) == '<')
2145 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2146 && code != NE_EXPR && code != EQ_EXPR)
2147 return build1 (TRUTH_NOT_EXPR, type, arg);
2149 return build (invert_tree_comparison (code), type,
2150 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2156 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2157 && TREE_INT_CST_HIGH (arg) == 0, 0));
2159 case TRUTH_AND_EXPR:
2160 return build (TRUTH_OR_EXPR, type,
2161 invert_truthvalue (TREE_OPERAND (arg, 0)),
2162 invert_truthvalue (TREE_OPERAND (arg, 1)));
2165 return build (TRUTH_AND_EXPR, type,
2166 invert_truthvalue (TREE_OPERAND (arg, 0)),
2167 invert_truthvalue (TREE_OPERAND (arg, 1)));
2169 case TRUTH_XOR_EXPR:
2170 /* Here we can invert either operand. We invert the first operand
2171 unless the second operand is a TRUTH_NOT_EXPR in which case our
2172 result is the XOR of the first operand with the inside of the
2173 negation of the second operand. */
2175 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2176 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2177 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2179 return build (TRUTH_XOR_EXPR, type,
2180 invert_truthvalue (TREE_OPERAND (arg, 0)),
2181 TREE_OPERAND (arg, 1));
2183 case TRUTH_ANDIF_EXPR:
2184 return build (TRUTH_ORIF_EXPR, type,
2185 invert_truthvalue (TREE_OPERAND (arg, 0)),
2186 invert_truthvalue (TREE_OPERAND (arg, 1)));
2188 case TRUTH_ORIF_EXPR:
2189 return build (TRUTH_ANDIF_EXPR, type,
2190 invert_truthvalue (TREE_OPERAND (arg, 0)),
2191 invert_truthvalue (TREE_OPERAND (arg, 1)));
2193 case TRUTH_NOT_EXPR:
2194 return TREE_OPERAND (arg, 0);
2197 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2198 invert_truthvalue (TREE_OPERAND (arg, 1)),
2199 invert_truthvalue (TREE_OPERAND (arg, 2)));
2202 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2203 invert_truthvalue (TREE_OPERAND (arg, 1)));
2205 case NON_LVALUE_EXPR:
2206 return invert_truthvalue (TREE_OPERAND (arg, 0));
2211 return build1 (TREE_CODE (arg), type,
2212 invert_truthvalue (TREE_OPERAND (arg, 0)));
2215 if (!integer_onep (TREE_OPERAND (arg, 1)))
2217 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2220 return build1 (TRUTH_NOT_EXPR, type, arg);
2222 case CLEANUP_POINT_EXPR:
2223 return build1 (CLEANUP_POINT_EXPR, type,
2224 invert_truthvalue (TREE_OPERAND (arg, 0)));
2226 if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
2228 return build1 (TRUTH_NOT_EXPR, type, arg);
2231 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2232 operands are another bit-wise operation with a common input. If so,
2233 distribute the bit operations to save an operation and possibly two if
2234 constants are involved. For example, convert
2235 (A | B) & (A | C) into A | (B & C)
2236 Further simplification will occur if B and C are constants.
2238 If this optimization cannot be done, 0 will be returned. */
2241 distribute_bit_expr (code, type, arg0, arg1)
2242 enum tree_code code;
2249 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2250 || TREE_CODE (arg0) == code
2251 || (TREE_CODE (arg0) != BIT_AND_EXPR
2252 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2255 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2257 common = TREE_OPERAND (arg0, 0);
2258 left = TREE_OPERAND (arg0, 1);
2259 right = TREE_OPERAND (arg1, 1);
2261 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2263 common = TREE_OPERAND (arg0, 0);
2264 left = TREE_OPERAND (arg0, 1);
2265 right = TREE_OPERAND (arg1, 0);
2267 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2269 common = TREE_OPERAND (arg0, 1);
2270 left = TREE_OPERAND (arg0, 0);
2271 right = TREE_OPERAND (arg1, 1);
2273 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2275 common = TREE_OPERAND (arg0, 1);
2276 left = TREE_OPERAND (arg0, 0);
2277 right = TREE_OPERAND (arg1, 0);
2282 return fold (build (TREE_CODE (arg0), type, common,
2283 fold (build (code, type, left, right))));
2286 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2287 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2290 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2293 int bitsize, bitpos;
2296 tree result = build (BIT_FIELD_REF, type, inner,
2297 size_int (bitsize), size_int (bitpos));
2299 TREE_UNSIGNED (result) = unsignedp;
2304 /* Optimize a bit-field compare.
2306 There are two cases: First is a compare against a constant and the
2307 second is a comparison of two items where the fields are at the same
2308 bit position relative to the start of a chunk (byte, halfword, word)
2309 large enough to contain it. In these cases we can avoid the shift
2310 implicit in bitfield extractions.
2312 For constants, we emit a compare of the shifted constant with the
2313 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2314 compared. For two fields at the same position, we do the ANDs with the
2315 similar mask and compare the result of the ANDs.
2317 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2318 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2319 are the left and right operands of the comparison, respectively.
2321 If the optimization described above can be done, we return the resulting
2322 tree. Otherwise we return zero. */
2325 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2326 enum tree_code code;
2330 int lbitpos, lbitsize, rbitpos, rbitsize;
2331 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2332 tree type = TREE_TYPE (lhs);
2333 tree signed_type, unsigned_type;
2334 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2335 enum machine_mode lmode, rmode, lnmode, rnmode;
2336 int lunsignedp, runsignedp;
2337 int lvolatilep = 0, rvolatilep = 0;
2339 tree linner, rinner;
2343 /* Get all the information about the extractions being done. If the bit size
2344 if the same as the size of the underlying object, we aren't doing an
2345 extraction at all and so can do nothing. */
2346 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2347 &lunsignedp, &lvolatilep, &alignment);
2348 if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2354 /* If this is not a constant, we can only do something if bit positions,
2355 sizes, and signedness are the same. */
2356 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
2357 &runsignedp, &rvolatilep, &alignment);
2359 if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
2360 || lunsignedp != runsignedp || offset != 0)
2364 /* See if we can find a mode to refer to this field. We should be able to,
2365 but fail if we can't. */
2366 lnmode = get_best_mode (lbitsize, lbitpos,
2367 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2369 if (lnmode == VOIDmode)
2372 /* Set signed and unsigned types of the precision of this mode for the
2374 signed_type = type_for_mode (lnmode, 0);
2375 unsigned_type = type_for_mode (lnmode, 1);
2379 rnmode = get_best_mode (rbitsize, rbitpos,
2380 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2382 if (rnmode == VOIDmode)
2386 /* Compute the bit position and size for the new reference and our offset
2387 within it. If the new reference is the same size as the original, we
2388 won't optimize anything, so return zero. */
2389 lnbitsize = GET_MODE_BITSIZE (lnmode);
2390 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2391 lbitpos -= lnbitpos;
2392 if (lnbitsize == lbitsize)
2397 rnbitsize = GET_MODE_BITSIZE (rnmode);
2398 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2399 rbitpos -= rnbitpos;
2400 if (rnbitsize == rbitsize)
2404 if (BYTES_BIG_ENDIAN)
2405 lbitpos = lnbitsize - lbitsize - lbitpos;
2407 /* Make the mask to be used against the extracted field. */
2408 mask = build_int_2 (~0, ~0);
2409 TREE_TYPE (mask) = unsigned_type;
2410 force_fit_type (mask, 0);
2411 mask = convert (unsigned_type, mask);
2412 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2413 mask = const_binop (RSHIFT_EXPR, mask,
2414 size_int (lnbitsize - lbitsize - lbitpos), 0);
2417 /* If not comparing with constant, just rework the comparison
2419 return build (code, compare_type,
2420 build (BIT_AND_EXPR, unsigned_type,
2421 make_bit_field_ref (linner, unsigned_type,
2422 lnbitsize, lnbitpos, 1),
2424 build (BIT_AND_EXPR, unsigned_type,
2425 make_bit_field_ref (rinner, unsigned_type,
2426 rnbitsize, rnbitpos, 1),
2429 /* Otherwise, we are handling the constant case. See if the constant is too
2430 big for the field. Warn and return a tree of for 0 (false) if so. We do
2431 this not only for its own sake, but to avoid having to test for this
2432 error case below. If we didn't, we might generate wrong code.
2434 For unsigned fields, the constant shifted right by the field length should
2435 be all zero. For signed fields, the high-order bits should agree with
2440 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2441 convert (unsigned_type, rhs),
2442 size_int (lbitsize), 0)))
2444 warning ("comparison is always %s due to width of bitfield",
2445 code == NE_EXPR ? "one" : "zero");
2446 return convert (compare_type,
2448 ? integer_one_node : integer_zero_node));
2453 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2454 size_int (lbitsize - 1), 0);
2455 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2457 warning ("comparison is always %s due to width of bitfield",
2458 code == NE_EXPR ? "one" : "zero");
2459 return convert (compare_type,
2461 ? integer_one_node : integer_zero_node));
2465 /* Single-bit compares should always be against zero. */
2466 if (lbitsize == 1 && ! integer_zerop (rhs))
2468 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2469 rhs = convert (type, integer_zero_node);
2472 /* Make a new bitfield reference, shift the constant over the
2473 appropriate number of bits and mask it with the computed mask
2474 (in case this was a signed field). If we changed it, make a new one. */
2475 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2478 TREE_SIDE_EFFECTS (lhs) = 1;
2479 TREE_THIS_VOLATILE (lhs) = 1;
2482 rhs = fold (const_binop (BIT_AND_EXPR,
2483 const_binop (LSHIFT_EXPR,
2484 convert (unsigned_type, rhs),
2485 size_int (lbitpos), 0),
2488 return build (code, compare_type,
2489 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2493 /* Subroutine for fold_truthop: decode a field reference.
2495 If EXP is a comparison reference, we return the innermost reference.
2497 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2498 set to the starting bit number.
2500 If the innermost field can be completely contained in a mode-sized
2501 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2503 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2504 otherwise it is not changed.
2506 *PUNSIGNEDP is set to the signedness of the field.
2508 *PMASK is set to the mask used. This is either contained in a
2509 BIT_AND_EXPR or derived from the width of the field.
2511 *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any.
2513 Return 0 if this is not a component reference or is one that we can't
2514 do anything with. */
2517 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2518 pvolatilep, pmask, pand_mask)
2520 int *pbitsize, *pbitpos;
2521 enum machine_mode *pmode;
2522 int *punsignedp, *pvolatilep;
2527 tree mask, inner, offset;
2532 /* All the optimizations using this function assume integer fields.
2533 There are problems with FP fields since the type_for_size call
2534 below can fail for, e.g., XFmode. */
2535 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2540 if (TREE_CODE (exp) == BIT_AND_EXPR)
2542 and_mask = TREE_OPERAND (exp, 1);
2543 exp = TREE_OPERAND (exp, 0);
2544 STRIP_NOPS (exp); STRIP_NOPS (and_mask);
2545 if (TREE_CODE (and_mask) != INTEGER_CST)
2550 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2551 punsignedp, pvolatilep, &alignment);
2552 if ((inner == exp && and_mask == 0)
2553 || *pbitsize < 0 || offset != 0)
2556 /* Compute the mask to access the bitfield. */
2557 unsigned_type = type_for_size (*pbitsize, 1);
2558 precision = TYPE_PRECISION (unsigned_type);
2560 mask = build_int_2 (~0, ~0);
2561 TREE_TYPE (mask) = unsigned_type;
2562 force_fit_type (mask, 0);
2563 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2564 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2566 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
2568 mask = fold (build (BIT_AND_EXPR, unsigned_type,
2569 convert (unsigned_type, and_mask), mask));
2572 *pand_mask = and_mask;
2576 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2580 all_ones_mask_p (mask, size)
2584 tree type = TREE_TYPE (mask);
2585 int precision = TYPE_PRECISION (type);
2588 tmask = build_int_2 (~0, ~0);
2589 TREE_TYPE (tmask) = signed_type (type);
2590 force_fit_type (tmask, 0);
2592 tree_int_cst_equal (mask,
2593 const_binop (RSHIFT_EXPR,
2594 const_binop (LSHIFT_EXPR, tmask,
2595 size_int (precision - size),
2597 size_int (precision - size), 0));
2600 /* Subroutine for fold_truthop: determine if an operand is simple enough
2601 to be evaluated unconditionally. */
2604 simple_operand_p (exp)
2607 /* Strip any conversions that don't change the machine mode. */
2608 while ((TREE_CODE (exp) == NOP_EXPR
2609 || TREE_CODE (exp) == CONVERT_EXPR)
2610 && (TYPE_MODE (TREE_TYPE (exp))
2611 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2612 exp = TREE_OPERAND (exp, 0);
2614 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2615 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2616 && ! TREE_ADDRESSABLE (exp)
2617 && ! TREE_THIS_VOLATILE (exp)
2618 && ! DECL_NONLOCAL (exp)
2619 /* Don't regard global variables as simple. They may be
2620 allocated in ways unknown to the compiler (shared memory,
2621 #pragma weak, etc). */
2622 && ! TREE_PUBLIC (exp)
2623 && ! DECL_EXTERNAL (exp)
2624 /* Loading a static variable is unduly expensive, but global
2625 registers aren't expensive. */
2626 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2629 /* The following functions are subroutines to fold_range_test and allow it to
2630 try to change a logical combination of comparisons into a range test.
2633 X == 2 && X == 3 && X == 4 && X == 5
2637 (unsigned) (X - 2) <= 3
2639 We decribe each set of comparisons as being either inside or outside
2640 a range, using a variable named like IN_P, and then describe the
2641 range with a lower and upper bound. If one of the bounds is omitted,
2642 it represents either the highest or lowest value of the type.
2644 In the comments below, we represent a range by two numbers in brackets
2645 preceeded by a "+" to designate being inside that range, or a "-" to
2646 designate being outside that range, so the condition can be inverted by
2647 flipping the prefix. An omitted bound is represented by a "-". For
2648 example, "- [-, 10]" means being outside the range starting at the lowest
2649 possible value and ending at 10, in other words, being greater than 10.
2650 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
2653 We set up things so that the missing bounds are handled in a consistent
2654 manner so neither a missing bound nor "true" and "false" need to be
2655 handled using a special case. */
2657 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
2658 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
2659 and UPPER1_P are nonzero if the respective argument is an upper bound
2660 and zero for a lower. TYPE, if nonzero, is the type of the result; it
2661 must be specified for a comparison. ARG1 will be converted to ARG0's
2662 type if both are specified. */
2665 range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
2666 enum tree_code code;
2669 int upper0_p, upper1_p;
2675 /* If neither arg represents infinity, do the normal operation.
2676 Else, if not a comparison, return infinity. Else handle the special
2677 comparison rules. Note that most of the cases below won't occur, but
2678 are handled for consistency. */
2680 if (arg0 != 0 && arg1 != 0)
2682 tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
2683 arg0, convert (TREE_TYPE (arg0), arg1)));
2685 return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
2688 if (TREE_CODE_CLASS (code) != '<')
2691 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
2692 for neither. Then compute our result treating them as never equal
2693 and comparing bounds to non-bounds as above. */
2694 sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
2695 sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
2698 case EQ_EXPR: case NE_EXPR:
2699 result = (code == NE_EXPR);
2701 case LT_EXPR: case LE_EXPR:
2702 result = sgn0 < sgn1;
2704 case GT_EXPR: case GE_EXPR:
2705 result = sgn0 > sgn1;
2709 return convert (type, result ? integer_one_node : integer_zero_node);
2712 /* Given EXP, a logical expression, set the range it is testing into
2713 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
2714 actually being tested. *PLOW and *PHIGH will have be made the same type
2715 as the returned expression. If EXP is not a comparison, we will most
2716 likely not be returning a useful value and range. */
2719 make_range (exp, pin_p, plow, phigh)
2724 enum tree_code code;
2725 tree arg0, arg1, type;
2727 tree low, high, n_low, n_high;
2729 /* Start with simply saying "EXP != 0" and then look at the code of EXP
2730 and see if we can refine the range. Some of the cases below may not
2731 happen, but it doesn't seem worth worrying about this. We "continue"
2732 the outer loop when we've changed something; otherwise we "break"
2733 the switch, which will "break" the while. */
2735 in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
2739 code = TREE_CODE (exp);
2740 arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1);
2741 if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1'
2742 || TREE_CODE_CLASS (code) == '2')
2743 type = TREE_TYPE (arg0);
2747 case TRUTH_NOT_EXPR:
2748 in_p = ! in_p, exp = arg0;
2751 case EQ_EXPR: case NE_EXPR:
2752 case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
2753 /* We can only do something if the range is testing for zero
2754 and if the second operand is an integer constant. Note that
2755 saying something is "in" the range we make is done by
2756 complementing IN_P since it will set in the initial case of
2757 being not equal to zero; "out" is leaving it alone. */
2758 if (low == 0 || high == 0
2759 || ! integer_zerop (low) || ! integer_zerop (high)
2760 || TREE_CODE (arg1) != INTEGER_CST)
2765 case NE_EXPR: /* - [c, c] */
2768 case EQ_EXPR: /* + [c, c] */
2769 in_p = ! in_p, low = high = arg1;
2771 case GT_EXPR: /* - [-, c] */
2772 low = 0, high = arg1;
2774 case GE_EXPR: /* + [c, -] */
2775 in_p = ! in_p, low = arg1, high = 0;
2777 case LT_EXPR: /* - [c, -] */
2778 low = arg1, high = 0;
2780 case LE_EXPR: /* + [-, c] */
2781 in_p = ! in_p, low = 0, high = arg1;
2787 /* If this is an unsigned comparison, we also know that EXP is
2788 greater than or equal to zero. We base the range tests we make
2789 on that fact, so we record it here so we can parse existing
2791 if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
2793 if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
2794 1, convert (type, integer_zero_node),
2798 in_p = n_in_p, low = n_low, high = n_high;
2800 /* If the high bound is missing, reverse the range so it
2801 goes from zero to the low bound minus 1. */
2805 high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
2806 integer_one_node, 0);
2807 low = convert (type, integer_zero_node);
2813 /* (-x) IN [a,b] -> x in [-b, -a] */
2814 n_low = range_binop (MINUS_EXPR, type,
2815 convert (type, integer_zero_node), 0, high, 1);
2816 n_high = range_binop (MINUS_EXPR, type,
2817 convert (type, integer_zero_node), 0, low, 0);
2818 low = n_low, high = n_high;
2824 exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0),
2825 convert (type, integer_one_node));
2828 case PLUS_EXPR: case MINUS_EXPR:
2829 if (TREE_CODE (arg1) != INTEGER_CST)
2832 /* If EXP is signed, any overflow in the computation is undefined,
2833 so we don't worry about it so long as our computations on
2834 the bounds don't overflow. For unsigned, overflow is defined
2835 and this is exactly the right thing. */
2836 n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2837 type, low, 0, arg1, 0);
2838 n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
2839 type, high, 1, arg1, 0);
2840 if ((n_low != 0 && TREE_OVERFLOW (n_low))
2841 || (n_high != 0 && TREE_OVERFLOW (n_high)))
2844 /* Check for an unsigned range which has wrapped around the maximum
2845 value thus making n_high < n_low, and normalize it. */
2846 if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
2848 low = range_binop (PLUS_EXPR, type, n_high, 0,
2849 integer_one_node, 0);
2850 high = range_binop (MINUS_EXPR, type, n_low, 0,
2851 integer_one_node, 0);
2855 low = n_low, high = n_high;
2860 case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
2861 if (! INTEGRAL_TYPE_P (type)
2862 || (low != 0 && ! int_fits_type_p (low, type))
2863 || (high != 0 && ! int_fits_type_p (high, type)))
2866 n_low = low, n_high = high;
2869 n_low = convert (type, n_low);
2872 n_high = convert (type, n_high);
2874 /* If we're converting from an unsigned to a signed type,
2875 we will be doing the comparison as unsigned. The tests above
2876 have already verified that LOW and HIGH are both positive.
2878 So we have to make sure that the original unsigned value will
2879 be interpreted as positive. */
2880 if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
2882 tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
2884 = fold (build (RSHIFT_EXPR, type,
2886 TYPE_MAX_VALUE (equiv_type)),
2887 convert (type, integer_one_node)));
2889 /* If the low bound is specified, "and" the range with the
2890 range for which the original unsigned value will be
2894 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2896 1, convert (type, integer_zero_node),
2900 in_p = (n_in_p == in_p);
2904 /* Otherwise, "or" the range with the range of the input
2905 that will be interpreted as negative. */
2906 if (! merge_ranges (&n_in_p, &n_low, &n_high,
2908 1, convert (type, integer_zero_node),
2912 in_p = (in_p != n_in_p);
2917 low = n_low, high = n_high;
2927 /* If EXP is a constant, we can evaluate whether this is true or false. */
2928 if (TREE_CODE (exp) == INTEGER_CST)
2930 in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
2932 && integer_onep (range_binop (LE_EXPR, integer_type_node,
2938 *pin_p = in_p, *plow = low, *phigh = high;
2942 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
2943 type, TYPE, return an expression to test if EXP is in (or out of, depending
2944 on IN_P) the range. */
2947 build_range_check (type, exp, in_p, low, high)
2953 tree etype = TREE_TYPE (exp);
2957 && (0 != (value = build_range_check (type, exp, 1, low, high))))
2958 return invert_truthvalue (value);
2960 else if (low == 0 && high == 0)
2961 return convert (type, integer_one_node);
2964 return fold (build (LE_EXPR, type, exp, high));
2967 return fold (build (GE_EXPR, type, exp, low));
2969 else if (operand_equal_p (low, high, 0))
2970 return fold (build (EQ_EXPR, type, exp, low));
2972 else if (TREE_UNSIGNED (etype) && integer_zerop (low))
2973 return build_range_check (type, exp, 1, 0, high);
2975 else if (integer_zerop (low))
2977 utype = unsigned_type (etype);
2978 return build_range_check (type, convert (utype, exp), 1, 0,
2979 convert (utype, high));
2982 else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
2983 && ! TREE_OVERFLOW (value))
2984 return build_range_check (type,
2985 fold (build (MINUS_EXPR, etype, exp, low)),
2986 1, convert (etype, integer_zero_node), value);
2991 /* Given two ranges, see if we can merge them into one. Return 1 if we
2992 can, 0 if we can't. Set the output range into the specified parameters. */
2995 merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
2999 tree low0, high0, low1, high1;
3007 int lowequal = ((low0 == 0 && low1 == 0)
3008 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3009 low0, 0, low1, 0)));
3010 int highequal = ((high0 == 0 && high1 == 0)
3011 || integer_onep (range_binop (EQ_EXPR, integer_type_node,
3012 high0, 1, high1, 1)));
3014 /* Make range 0 be the range that starts first, or ends last if they
3015 start at the same value. Swap them if it isn't. */
3016 if (integer_onep (range_binop (GT_EXPR, integer_type_node,
3019 && integer_onep (range_binop (GT_EXPR, integer_type_node,
3020 high1, 1, high0, 1))))
3022 temp = in0_p, in0_p = in1_p, in1_p = temp;
3023 tem = low0, low0 = low1, low1 = tem;
3024 tem = high0, high0 = high1, high1 = tem;
3027 /* Now flag two cases, whether the ranges are disjoint or whether the
3028 second range is totally subsumed in the first. Note that the tests
3029 below are simplified by the ones above. */
3030 no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
3031 high0, 1, low1, 0));
3032 subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
3033 high1, 1, high0, 1));
3035 /* We now have four cases, depending on whether we are including or
3036 excluding the two ranges. */
3039 /* If they don't overlap, the result is false. If the second range
3040 is a subset it is the result. Otherwise, the range is from the start
3041 of the second to the end of the first. */
3043 in_p = 0, low = high = 0;
3045 in_p = 1, low = low1, high = high1;
3047 in_p = 1, low = low1, high = high0;
3050 else if (in0_p && ! in1_p)
3052 /* If they don't overlap, the result is the first range. If they are
3053 equal, the result is false. If the second range is a subset of the
3054 first, and the ranges begin at the same place, we go from just after
3055 the end of the first range to the end of the second. If the second
3056 range is not a subset of the first, or if it is a subset and both
3057 ranges end at the same place, the range starts at the start of the
3058 first range and ends just before the second range.
3059 Otherwise, we can't describe this as a single range. */
3061 in_p = 1, low = low0, high = high0;
3062 else if (lowequal && highequal)
3063 in_p = 0, low = high = 0;
3064 else if (subset && lowequal)
3066 in_p = 1, high = high0;
3067 low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
3068 integer_one_node, 0);
3070 else if (! subset || highequal)
3072 in_p = 1, low = low0;
3073 high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
3074 integer_one_node, 0);
3080 else if (! in0_p && in1_p)
3082 /* If they don't overlap, the result is the second range. If the second
3083 is a subset of the first, the result is false. Otherwise,
3084 the range starts just after the first range and ends at the
3085 end of the second. */
3087 in_p = 1, low = low1, high = high1;
3089 in_p = 0, low = high = 0;
3092 in_p = 1, high = high1;
3093 low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
3094 integer_one_node, 0);
3100 /* The case where we are excluding both ranges. Here the complex case
3101 is if they don't overlap. In that case, the only time we have a
3102 range is if they are adjacent. If the second is a subset of the
3103 first, the result is the first. Otherwise, the range to exclude
3104 starts at the beginning of the first range and ends at the end of the
3108 if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
3109 range_binop (PLUS_EXPR, NULL_TREE,
3111 integer_one_node, 1),
3113 in_p = 0, low = low0, high = high1;
3118 in_p = 0, low = low0, high = high0;
3120 in_p = 0, low = low0, high = high1;
3123 *pin_p = in_p, *plow = low, *phigh = high;
3127 /* EXP is some logical combination of boolean tests. See if we can
3128 merge it into some range test. Return the new tree if so. */
3131 fold_range_test (exp)
3134 int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
3135 || TREE_CODE (exp) == TRUTH_OR_EXPR);
3136 int in0_p, in1_p, in_p;
3137 tree low0, low1, low, high0, high1, high;
3138 tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
3139 tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
3142 /* If this is an OR operation, invert both sides; we will invert
3143 again at the end. */
3145 in0_p = ! in0_p, in1_p = ! in1_p;
3147 /* If both expressions are the same, if we can merge the ranges, and we
3148 can build the range test, return it or it inverted. If one of the
3149 ranges is always true or always false, consider it to be the same
3150 expression as the other. */
3151 if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
3152 && merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
3154 && 0 != (tem = (build_range_check (TREE_TYPE (exp),
3156 : rhs != 0 ? rhs : integer_zero_node,
3158 return or_op ? invert_truthvalue (tem) : tem;
3160 /* On machines where the branch cost is expensive, if this is a
3161 short-circuited branch and the underlying object on both sides
3162 is the same, make a non-short-circuit operation. */
3163 else if (BRANCH_COST >= 2
3164 && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3165 || TREE_CODE (exp) == TRUTH_ORIF_EXPR)
3166 && operand_equal_p (lhs, rhs, 0))
3168 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
3169 unless we are at top level, in which case we can't do this. */
3170 if (simple_operand_p (lhs))
3171 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3172 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3173 TREE_TYPE (exp), TREE_OPERAND (exp, 0),
3174 TREE_OPERAND (exp, 1));
3176 else if (current_function_decl != 0)
3178 tree common = save_expr (lhs);
3180 if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
3181 or_op ? ! in0_p : in0_p,
3183 && (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
3184 or_op ? ! in1_p : in1_p,
3186 return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
3187 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3188 TREE_TYPE (exp), lhs, rhs);
3195 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
3196 bit value. Arrange things so the extra bits will be set to zero if and
3197 only if C is signed-extended to its full width. If MASK is nonzero,
3198 it is an INTEGER_CST that should be AND'ed with the extra bits. */
3201 unextend (c, p, unsignedp, mask)
3207 tree type = TREE_TYPE (c);
3208 int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
3211 if (p == modesize || unsignedp)
3214 /* We work by getting just the sign bit into the low-order bit, then
3215 into the high-order bit, then sign-extend. We then XOR that value
3217 temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
3218 temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
3220 /* We must use a signed type in order to get an arithmetic right shift.
3221 However, we must also avoid introducing accidental overflows, so that
3222 a subsequent call to integer_zerop will work. Hence we must
3223 do the type conversion here. At this point, the constant is either
3224 zero or one, and the conversion to a signed type can never overflow.
3225 We could get an overflow if this conversion is done anywhere else. */
3226 if (TREE_UNSIGNED (type))
3227 temp = convert (signed_type (type), temp);
3229 temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
3230 temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
3232 temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
3233 /* If necessary, convert the type back to match the type of C. */
3234 if (TREE_UNSIGNED (type))
3235 temp = convert (type, temp);
3237 return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
3240 /* Find ways of folding logical expressions of LHS and RHS:
3241 Try to merge two comparisons to the same innermost item.
3242 Look for range tests like "ch >= '0' && ch <= '9'".
3243 Look for combinations of simple terms on machines with expensive branches
3244 and evaluate the RHS unconditionally.
3246 For example, if we have p->a == 2 && p->b == 4 and we can make an
3247 object large enough to span both A and B, we can do this with a comparison
3248 against the object ANDed with the a mask.
3250 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
3251 operations to do this with one comparison.
3253 We check for both normal comparisons and the BIT_AND_EXPRs made this by
3254 function and the one above.
3256 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
3257 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
3259 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
3262 We return the simplified tree or 0 if no optimization is possible. */
3265 fold_truthop (code, truth_type, lhs, rhs)
3266 enum tree_code code;
3267 tree truth_type, lhs, rhs;
3269 /* If this is the "or" of two comparisons, we can do something if we
3270 the comparisons are NE_EXPR. If this is the "and", we can do something
3271 if the comparisons are EQ_EXPR. I.e.,
3272 (a->b == 2 && a->c == 4) can become (a->new == NEW).
3274 WANTED_CODE is this operation code. For single bit fields, we can
3275 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
3276 comparison for one-bit fields. */
3278 enum tree_code wanted_code;
3279 enum tree_code lcode, rcode;
3280 tree ll_arg, lr_arg, rl_arg, rr_arg;
3281 tree ll_inner, lr_inner, rl_inner, rr_inner;
3282 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
3283 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
3284 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
3285 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
3286 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
3287 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
3288 enum machine_mode lnmode, rnmode;
3289 tree ll_mask, lr_mask, rl_mask, rr_mask;
3290 tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
3291 tree l_const, r_const;
3293 int first_bit, end_bit;
3296 /* Start by getting the comparison codes. Fail if anything is volatile.
3297 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
3298 it were surrounded with a NE_EXPR. */
3300 if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
3303 lcode = TREE_CODE (lhs);
3304 rcode = TREE_CODE (rhs);
3306 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
3307 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
3309 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
3310 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
3312 if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
3315 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
3316 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
3318 ll_arg = TREE_OPERAND (lhs, 0);
3319 lr_arg = TREE_OPERAND (lhs, 1);
3320 rl_arg = TREE_OPERAND (rhs, 0);
3321 rr_arg = TREE_OPERAND (rhs, 1);
3323 /* If the RHS can be evaluated unconditionally and its operands are
3324 simple, it wins to evaluate the RHS unconditionally on machines
3325 with expensive branches. In this case, this isn't a comparison
3326 that can be merged. */
3328 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
3329 are with zero (tmw). */
3331 if (BRANCH_COST >= 2
3332 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
3333 && simple_operand_p (rl_arg)
3334 && simple_operand_p (rr_arg))
3335 return build (code, truth_type, lhs, rhs);
3337 /* See if the comparisons can be merged. Then get all the parameters for
3340 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
3341 || (rcode != EQ_EXPR && rcode != NE_EXPR))
3345 ll_inner = decode_field_reference (ll_arg,
3346 &ll_bitsize, &ll_bitpos, &ll_mode,
3347 &ll_unsignedp, &volatilep, &ll_mask,
3349 lr_inner = decode_field_reference (lr_arg,
3350 &lr_bitsize, &lr_bitpos, &lr_mode,
3351 &lr_unsignedp, &volatilep, &lr_mask,
3353 rl_inner = decode_field_reference (rl_arg,
3354 &rl_bitsize, &rl_bitpos, &rl_mode,
3355 &rl_unsignedp, &volatilep, &rl_mask,
3357 rr_inner = decode_field_reference (rr_arg,
3358 &rr_bitsize, &rr_bitpos, &rr_mode,
3359 &rr_unsignedp, &volatilep, &rr_mask,
3362 /* It must be true that the inner operation on the lhs of each
3363 comparison must be the same if we are to be able to do anything.
3364 Then see if we have constants. If not, the same must be true for
3366 if (volatilep || ll_inner == 0 || rl_inner == 0
3367 || ! operand_equal_p (ll_inner, rl_inner, 0))
3370 if (TREE_CODE (lr_arg) == INTEGER_CST
3371 && TREE_CODE (rr_arg) == INTEGER_CST)
3372 l_const = lr_arg, r_const = rr_arg;
3373 else if (lr_inner == 0 || rr_inner == 0
3374 || ! operand_equal_p (lr_inner, rr_inner, 0))
3377 l_const = r_const = 0;
3379 /* If either comparison code is not correct for our logical operation,
3380 fail. However, we can convert a one-bit comparison against zero into
3381 the opposite comparison against that bit being set in the field. */
3383 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
3384 if (lcode != wanted_code)
3386 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
3392 if (rcode != wanted_code)
3394 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
3400 /* See if we can find a mode that contains both fields being compared on
3401 the left. If we can't, fail. Otherwise, update all constants and masks
3402 to be relative to a field of that size. */
3403 first_bit = MIN (ll_bitpos, rl_bitpos);
3404 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
3405 lnmode = get_best_mode (end_bit - first_bit, first_bit,
3406 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
3408 if (lnmode == VOIDmode)
3411 lnbitsize = GET_MODE_BITSIZE (lnmode);
3412 lnbitpos = first_bit & ~ (lnbitsize - 1);
3413 type = type_for_size (lnbitsize, 1);
3414 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
3416 if (BYTES_BIG_ENDIAN)
3418 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
3419 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
3422 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
3423 size_int (xll_bitpos), 0);
3424 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
3425 size_int (xrl_bitpos), 0);
3429 l_const = convert (type, l_const);
3430 l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
3431 l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
3432 if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
3433 fold (build1 (BIT_NOT_EXPR,
3437 warning ("comparison is always %s",
3438 wanted_code == NE_EXPR ? "one" : "zero");
3440 return convert (truth_type,
3441 wanted_code == NE_EXPR
3442 ? integer_one_node : integer_zero_node);
3447 r_const = convert (type, r_const);
3448 r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
3449 r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
3450 if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
3451 fold (build1 (BIT_NOT_EXPR,
3455 warning ("comparison is always %s",
3456 wanted_code == NE_EXPR ? "one" : "zero");
3458 return convert (truth_type,
3459 wanted_code == NE_EXPR
3460 ? integer_one_node : integer_zero_node);
3464 /* If the right sides are not constant, do the same for it. Also,
3465 disallow this optimization if a size or signedness mismatch occurs
3466 between the left and right sides. */
3469 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
3470 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
3471 /* Make sure the two fields on the right
3472 correspond to the left without being swapped. */
3473 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
3476 first_bit = MIN (lr_bitpos, rr_bitpos);
3477 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
3478 rnmode = get_best_mode (end_bit - first_bit, first_bit,
3479 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
3481 if (rnmode == VOIDmode)
3484 rnbitsize = GET_MODE_BITSIZE (rnmode);
3485 rnbitpos = first_bit & ~ (rnbitsize - 1);
3486 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
3488 if (BYTES_BIG_ENDIAN)
3490 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
3491 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
3494 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
3495 size_int (xlr_bitpos), 0);
3496 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
3497 size_int (xrr_bitpos), 0);
3499 /* Make a mask that corresponds to both fields being compared.
3500 Do this for both items being compared. If the masks agree,
3501 we can do this by masking both and comparing the masked
3503 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3504 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
3505 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
3507 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3508 ll_unsignedp || rl_unsignedp);
3509 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
3510 lr_unsignedp || rr_unsignedp);
3511 if (! all_ones_mask_p (ll_mask, lnbitsize))
3513 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
3514 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
3516 return build (wanted_code, truth_type, lhs, rhs);
3519 /* There is still another way we can do something: If both pairs of
3520 fields being compared are adjacent, we may be able to make a wider
3521 field containing them both. */
3522 if ((ll_bitsize + ll_bitpos == rl_bitpos
3523 && lr_bitsize + lr_bitpos == rr_bitpos)
3524 || (ll_bitpos == rl_bitpos + rl_bitsize
3525 && lr_bitpos == rr_bitpos + rr_bitsize))
3526 return build (wanted_code, truth_type,
3527 make_bit_field_ref (ll_inner, type,
3528 ll_bitsize + rl_bitsize,
3529 MIN (ll_bitpos, rl_bitpos),
3531 make_bit_field_ref (lr_inner, type,
3532 lr_bitsize + rr_bitsize,
3533 MIN (lr_bitpos, rr_bitpos),
3539 /* Handle the case of comparisons with constants. If there is something in
3540 common between the masks, those bits of the constants must be the same.
3541 If not, the condition is always false. Test for this to avoid generating
3542 incorrect code below. */
3543 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
3544 if (! integer_zerop (result)
3545 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
3546 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
3548 if (wanted_code == NE_EXPR)
3550 warning ("`or' of unmatched not-equal tests is always 1");
3551 return convert (truth_type, integer_one_node);
3555 warning ("`and' of mutually exclusive equal-tests is always zero");
3556 return convert (truth_type, integer_zero_node);
3560 /* Construct the expression we will return. First get the component
3561 reference we will make. Unless the mask is all ones the width of
3562 that field, perform the mask operation. Then compare with the
3564 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3565 ll_unsignedp || rl_unsignedp);
3567 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3568 if (! all_ones_mask_p (ll_mask, lnbitsize))
3569 result = build (BIT_AND_EXPR, type, result, ll_mask);
3571 return build (wanted_code, truth_type, result,
3572 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3575 /* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
3576 S, a SAVE_EXPR, return the expression actually being evaluated. Note
3577 that we may sometimes modify the tree. */
3580 strip_compound_expr (t, s)
3584 tree type = TREE_TYPE (t);
3585 enum tree_code code = TREE_CODE (t);
3587 /* See if this is the COMPOUND_EXPR we want to eliminate. */
3588 if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
3589 && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
3590 return TREE_OPERAND (t, 1);
3592 /* See if this is a COND_EXPR or a simple arithmetic operator. We
3593 don't bother handling any other types. */
3594 else if (code == COND_EXPR)
3596 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3597 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3598 TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
3600 else if (TREE_CODE_CLASS (code) == '1')
3601 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3602 else if (TREE_CODE_CLASS (code) == '<'
3603 || TREE_CODE_CLASS (code) == '2')
3605 TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
3606 TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
3612 /* Perform constant folding and related simplification of EXPR.
3613 The related simplifications include x*1 => x, x*0 => 0, etc.,
3614 and application of the associative law.
3615 NOP_EXPR conversions may be removed freely (as long as we
3616 are careful not to change the C type of the overall expression)
3617 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3618 but we can constant-fold them if they have constant operands. */
3624 register tree t = expr;
3625 tree t1 = NULL_TREE;
3627 tree type = TREE_TYPE (expr);
3628 register tree arg0, arg1;
3629 register enum tree_code code = TREE_CODE (t);
3633 /* WINS will be nonzero when the switch is done
3634 if all operands are constant. */
3638 /* Don't try to process an RTL_EXPR since its operands aren't trees.
3639 Likewise for a SAVE_EXPR that's already been evaluated. */
3640 if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0)
3643 /* Return right away if already constant. */
3644 if (TREE_CONSTANT (t))
3646 if (code == CONST_DECL)
3647 return DECL_INITIAL (t);
3651 kind = TREE_CODE_CLASS (code);
3652 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3656 /* Special case for conversion ops that can have fixed point args. */
3657 arg0 = TREE_OPERAND (t, 0);
3659 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3661 STRIP_TYPE_NOPS (arg0);
3663 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3664 subop = TREE_REALPART (arg0);
3668 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3669 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3670 && TREE_CODE (subop) != REAL_CST
3671 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3673 /* Note that TREE_CONSTANT isn't enough:
3674 static var addresses are constant but we can't
3675 do arithmetic on them. */
3678 else if (kind == 'e' || kind == '<'
3679 || kind == '1' || kind == '2' || kind == 'r')
3681 register int len = tree_code_length[(int) code];
3683 for (i = 0; i < len; i++)
3685 tree op = TREE_OPERAND (t, i);
3689 continue; /* Valid for CALL_EXPR, at least. */
3691 if (kind == '<' || code == RSHIFT_EXPR)
3693 /* Signedness matters here. Perhaps we can refine this
3695 STRIP_TYPE_NOPS (op);
3699 /* Strip any conversions that don't change the mode. */
3703 if (TREE_CODE (op) == COMPLEX_CST)
3704 subop = TREE_REALPART (op);
3708 if (TREE_CODE (subop) != INTEGER_CST
3709 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3710 && TREE_CODE (subop) != REAL_CST
3711 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3713 /* Note that TREE_CONSTANT isn't enough:
3714 static var addresses are constant but we can't
3715 do arithmetic on them. */
3725 /* If this is a commutative operation, and ARG0 is a constant, move it
3726 to ARG1 to reduce the number of tests below. */
3727 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3728 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3729 || code == BIT_AND_EXPR)
3730 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3732 tem = arg0; arg0 = arg1; arg1 = tem;
3734 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3735 TREE_OPERAND (t, 1) = tem;
3738 /* Now WINS is set as described above,
3739 ARG0 is the first operand of EXPR,
3740 and ARG1 is the second operand (if it has more than one operand).
3742 First check for cases where an arithmetic operation is applied to a
3743 compound, conditional, or comparison operation. Push the arithmetic
3744 operation inside the compound or conditional to see if any folding
3745 can then be done. Convert comparison to conditional for this purpose.
3746 The also optimizes non-constant cases that used to be done in
3749 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3750 one of the operands is a comparison and the other is a comparison, a
3751 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
3752 code below would make the expression more complex. Change it to a
3753 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
3754 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
3756 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
3757 || code == EQ_EXPR || code == NE_EXPR)
3758 && ((truth_value_p (TREE_CODE (arg0))
3759 && (truth_value_p (TREE_CODE (arg1))
3760 || (TREE_CODE (arg1) == BIT_AND_EXPR
3761 && integer_onep (TREE_OPERAND (arg1, 1)))))
3762 || (truth_value_p (TREE_CODE (arg1))
3763 && (truth_value_p (TREE_CODE (arg0))
3764 || (TREE_CODE (arg0) == BIT_AND_EXPR
3765 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3767 t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
3768 : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
3772 if (code == EQ_EXPR)
3773 t = invert_truthvalue (t);
3778 if (TREE_CODE_CLASS (code) == '1')
3780 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3781 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3782 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3783 else if (TREE_CODE (arg0) == COND_EXPR)
3785 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3786 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3787 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3789 /* If this was a conversion, and all we did was to move into
3790 inside the COND_EXPR, bring it back out. But leave it if
3791 it is a conversion from integer to integer and the
3792 result precision is no wider than a word since such a
3793 conversion is cheap and may be optimized away by combine,
3794 while it couldn't if it were outside the COND_EXPR. Then return
3795 so we don't get into an infinite recursion loop taking the
3796 conversion out and then back in. */
3798 if ((code == NOP_EXPR || code == CONVERT_EXPR
3799 || code == NON_LVALUE_EXPR)
3800 && TREE_CODE (t) == COND_EXPR
3801 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3802 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3803 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3804 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
3805 && ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
3806 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)))
3807 && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
3808 t = build1 (code, type,
3810 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3811 TREE_OPERAND (t, 0),
3812 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3813 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3816 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3817 return fold (build (COND_EXPR, type, arg0,
3818 fold (build1 (code, type, integer_one_node)),
3819 fold (build1 (code, type, integer_zero_node))));
3821 else if (TREE_CODE_CLASS (code) == '2'
3822 || TREE_CODE_CLASS (code) == '<')
3824 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3825 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3826 fold (build (code, type,
3827 arg0, TREE_OPERAND (arg1, 1))));
3828 else if ((TREE_CODE (arg1) == COND_EXPR
3829 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3830 && TREE_CODE_CLASS (code) != '<'))
3831 && (! TREE_SIDE_EFFECTS (arg0) || current_function_decl != 0))
3833 tree test, true_value, false_value;
3835 if (TREE_CODE (arg1) == COND_EXPR)
3837 test = TREE_OPERAND (arg1, 0);
3838 true_value = TREE_OPERAND (arg1, 1);
3839 false_value = TREE_OPERAND (arg1, 2);
3843 tree testtype = TREE_TYPE (arg1);
3845 true_value = convert (testtype, integer_one_node);
3846 false_value = convert (testtype, integer_zero_node);
3849 /* If ARG0 is complex we want to make sure we only evaluate
3850 it once. Though this is only required if it is volatile, it
3851 might be more efficient even if it is not. However, if we
3852 succeed in folding one part to a constant, we do not need
3853 to make this SAVE_EXPR. Since we do this optimization
3854 primarily to see if we do end up with constant and this
3855 SAVE_EXPR interferes with later optimizations, suppressing
3856 it when we can is important. */
3858 if (TREE_CODE (arg0) != SAVE_EXPR
3859 && ((TREE_CODE (arg0) != VAR_DECL
3860 && TREE_CODE (arg0) != PARM_DECL)
3861 || TREE_SIDE_EFFECTS (arg0)))
3863 tree lhs = fold (build (code, type, arg0, true_value));
3864 tree rhs = fold (build (code, type, arg0, false_value));
3866 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3867 return fold (build (COND_EXPR, type, test, lhs, rhs));
3869 if (current_function_decl != 0)
3870 arg0 = save_expr (arg0);
3873 test = fold (build (COND_EXPR, type, test,
3874 fold (build (code, type, arg0, true_value)),
3875 fold (build (code, type, arg0, false_value))));
3876 if (TREE_CODE (arg0) == SAVE_EXPR)
3877 return build (COMPOUND_EXPR, type,
3878 convert (void_type_node, arg0),
3879 strip_compound_expr (test, arg0));
3881 return convert (type, test);
3884 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3885 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3886 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3887 else if ((TREE_CODE (arg0) == COND_EXPR
3888 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3889 && TREE_CODE_CLASS (code) != '<'))
3890 && (! TREE_SIDE_EFFECTS (arg1) || current_function_decl != 0))
3892 tree test, true_value, false_value;
3894 if (TREE_CODE (arg0) == COND_EXPR)
3896 test = TREE_OPERAND (arg0, 0);
3897 true_value = TREE_OPERAND (arg0, 1);
3898 false_value = TREE_OPERAND (arg0, 2);
3902 tree testtype = TREE_TYPE (arg0);
3904 true_value = convert (testtype, integer_one_node);
3905 false_value = convert (testtype, integer_zero_node);
3908 if (TREE_CODE (arg1) != SAVE_EXPR
3909 && ((TREE_CODE (arg1) != VAR_DECL
3910 && TREE_CODE (arg1) != PARM_DECL)
3911 || TREE_SIDE_EFFECTS (arg1)))
3913 tree lhs = fold (build (code, type, true_value, arg1));
3914 tree rhs = fold (build (code, type, false_value, arg1));
3916 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)
3917 || TREE_CONSTANT (arg1))
3918 return fold (build (COND_EXPR, type, test, lhs, rhs));
3920 if (current_function_decl != 0)
3921 arg1 = save_expr (arg1);
3924 test = fold (build (COND_EXPR, type, test,
3925 fold (build (code, type, true_value, arg1)),
3926 fold (build (code, type, false_value, arg1))));
3927 if (TREE_CODE (arg1) == SAVE_EXPR)
3928 return build (COMPOUND_EXPR, type,
3929 convert (void_type_node, arg1),
3930 strip_compound_expr (test, arg1));
3932 return convert (type, test);
3935 else if (TREE_CODE_CLASS (code) == '<'
3936 && TREE_CODE (arg0) == COMPOUND_EXPR)
3937 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3938 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3939 else if (TREE_CODE_CLASS (code) == '<'
3940 && TREE_CODE (arg1) == COMPOUND_EXPR)
3941 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3942 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3954 return fold (DECL_INITIAL (t));
3959 case FIX_TRUNC_EXPR:
3960 /* Other kinds of FIX are not handled properly by fold_convert. */
3962 if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
3963 return TREE_OPERAND (t, 0);
3965 /* Handle cases of two conversions in a row. */
3966 if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
3967 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
3969 tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3970 tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
3971 tree final_type = TREE_TYPE (t);
3972 int inside_int = INTEGRAL_TYPE_P (inside_type);
3973 int inside_ptr = POINTER_TYPE_P (inside_type);
3974 int inside_float = FLOAT_TYPE_P (inside_type);
3975 int inside_prec = TYPE_PRECISION (inside_type);
3976 int inside_unsignedp = TREE_UNSIGNED (inside_type);
3977 int inter_int = INTEGRAL_TYPE_P (inter_type);
3978 int inter_ptr = POINTER_TYPE_P (inter_type);
3979 int inter_float = FLOAT_TYPE_P (inter_type);
3980 int inter_prec = TYPE_PRECISION (inter_type);
3981 int inter_unsignedp = TREE_UNSIGNED (inter_type);
3982 int final_int = INTEGRAL_TYPE_P (final_type);
3983 int final_ptr = POINTER_TYPE_P (final_type);
3984 int final_float = FLOAT_TYPE_P (final_type);
3985 int final_prec = TYPE_PRECISION (final_type);
3986 int final_unsignedp = TREE_UNSIGNED (final_type);
3988 /* In addition to the cases of two conversions in a row
3989 handled below, if we are converting something to its own
3990 type via an object of identical or wider precision, neither
3991 conversion is needed. */
3992 if (inside_type == final_type
3993 && ((inter_int && final_int) || (inter_float && final_float))
3994 && inter_prec >= final_prec)
3995 return TREE_OPERAND (TREE_OPERAND (t, 0), 0);
3997 /* Likewise, if the intermediate and final types are either both
3998 float or both integer, we don't need the middle conversion if
3999 it is wider than the final type and doesn't change the signedness
4000 (for integers). Avoid this if the final type is a pointer
4001 since then we sometimes need the inner conversion. Likewise if
4002 the outer has a precision not equal to the size of its mode. */
4003 if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
4004 || (inter_float && inside_float))
4005 && inter_prec >= inside_prec
4006 && (inter_float || inter_unsignedp == inside_unsignedp)
4007 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4008 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4010 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4012 /* Two conversions in a row are not needed unless:
4013 - some conversion is floating-point (overstrict for now), or
4014 - the intermediate type is narrower than both initial and
4016 - the intermediate type and innermost type differ in signedness,
4017 and the outermost type is wider than the intermediate, or
4018 - the initial type is a pointer type and the precisions of the
4019 intermediate and final types differ, or
4020 - the final type is a pointer type and the precisions of the
4021 initial and intermediate types differ. */
4022 if (! inside_float && ! inter_float && ! final_float
4023 && (inter_prec > inside_prec || inter_prec > final_prec)
4024 && ! (inside_int && inter_int
4025 && inter_unsignedp != inside_unsignedp
4026 && inter_prec < final_prec)
4027 && ((inter_unsignedp && inter_prec > inside_prec)
4028 == (final_unsignedp && final_prec > inter_prec))
4029 && ! (inside_ptr && inter_prec != final_prec)
4030 && ! (final_ptr && inside_prec != inter_prec)
4031 && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
4032 && TYPE_MODE (final_type) == TYPE_MODE (inter_type))
4034 return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
4037 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
4038 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
4039 /* Detect assigning a bitfield. */
4040 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
4041 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
4043 /* Don't leave an assignment inside a conversion
4044 unless assigning a bitfield. */
4045 tree prev = TREE_OPERAND (t, 0);
4046 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
4047 /* First do the assignment, then return converted constant. */
4048 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
4054 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
4057 return fold_convert (t, arg0);
4059 #if 0 /* This loses on &"foo"[0]. */
4064 /* Fold an expression like: "foo"[2] */
4065 if (TREE_CODE (arg0) == STRING_CST
4066 && TREE_CODE (arg1) == INTEGER_CST
4067 && !TREE_INT_CST_HIGH (arg1)
4068 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
4070 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
4071 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
4072 force_fit_type (t, 0);
4079 if (TREE_CODE (arg0) == CONSTRUCTOR)
4081 tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
4088 TREE_CONSTANT (t) = wins;
4094 if (TREE_CODE (arg0) == INTEGER_CST)
4096 HOST_WIDE_INT low, high;
4097 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4098 TREE_INT_CST_HIGH (arg0),
4100 t = build_int_2 (low, high);
4101 TREE_TYPE (t) = type;
4103 = (TREE_OVERFLOW (arg0)
4104 | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
4105 TREE_CONSTANT_OVERFLOW (t)
4106 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4108 else if (TREE_CODE (arg0) == REAL_CST)
4109 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4111 else if (TREE_CODE (arg0) == NEGATE_EXPR)
4112 return TREE_OPERAND (arg0, 0);
4114 /* Convert - (a - b) to (b - a) for non-floating-point. */
4115 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
4116 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
4117 TREE_OPERAND (arg0, 0));
4124 if (TREE_CODE (arg0) == INTEGER_CST)
4126 if (! TREE_UNSIGNED (type)
4127 && TREE_INT_CST_HIGH (arg0) < 0)
4129 HOST_WIDE_INT low, high;
4130 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
4131 TREE_INT_CST_HIGH (arg0),
4133 t = build_int_2 (low, high);
4134 TREE_TYPE (t) = type;
4136 = (TREE_OVERFLOW (arg0)
4137 | force_fit_type (t, overflow));
4138 TREE_CONSTANT_OVERFLOW (t)
4139 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
4142 else if (TREE_CODE (arg0) == REAL_CST)
4144 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
4145 t = build_real (type,
4146 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
4149 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
4150 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
4154 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4156 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4157 return build (COMPLEX_EXPR, TREE_TYPE (arg0),
4158 TREE_OPERAND (arg0, 0),
4159 fold (build1 (NEGATE_EXPR,
4160 TREE_TYPE (TREE_TYPE (arg0)),
4161 TREE_OPERAND (arg0, 1))));
4162 else if (TREE_CODE (arg0) == COMPLEX_CST)
4163 return build_complex (type, TREE_OPERAND (arg0, 0),
4164 fold (build1 (NEGATE_EXPR,
4165 TREE_TYPE (TREE_TYPE (arg0)),
4166 TREE_OPERAND (arg0, 1))));
4167 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4168 return fold (build (TREE_CODE (arg0), type,
4169 fold (build1 (CONJ_EXPR, type,
4170 TREE_OPERAND (arg0, 0))),
4171 fold (build1 (CONJ_EXPR,
4172 type, TREE_OPERAND (arg0, 1)))));
4173 else if (TREE_CODE (arg0) == CONJ_EXPR)
4174 return TREE_OPERAND (arg0, 0);
4180 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
4181 ~ TREE_INT_CST_HIGH (arg0));
4182 TREE_TYPE (t) = type;
4183 force_fit_type (t, 0);
4184 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
4185 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
4187 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
4188 return TREE_OPERAND (arg0, 0);
4192 /* A + (-B) -> A - B */
4193 if (TREE_CODE (arg1) == NEGATE_EXPR)
4194 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4195 else if (! FLOAT_TYPE_P (type))
4197 if (integer_zerop (arg1))
4198 return non_lvalue (convert (type, arg0));
4200 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
4201 with a constant, and the two constants have no bits in common,
4202 we should treat this as a BIT_IOR_EXPR since this may produce more
4204 if (TREE_CODE (arg0) == BIT_AND_EXPR
4205 && TREE_CODE (arg1) == BIT_AND_EXPR
4206 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4207 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
4208 && integer_zerop (const_binop (BIT_AND_EXPR,
4209 TREE_OPERAND (arg0, 1),
4210 TREE_OPERAND (arg1, 1), 0)))
4212 code = BIT_IOR_EXPR;
4216 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
4217 about the case where C is a constant, just try one of the
4218 four possibilities. */
4220 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4221 && operand_equal_p (TREE_OPERAND (arg0, 1),
4222 TREE_OPERAND (arg1, 1), 0))
4223 return fold (build (MULT_EXPR, type,
4224 fold (build (PLUS_EXPR, type,
4225 TREE_OPERAND (arg0, 0),
4226 TREE_OPERAND (arg1, 0))),
4227 TREE_OPERAND (arg0, 1)));
4229 /* In IEEE floating point, x+0 may not equal x. */
4230 else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4232 && real_zerop (arg1))
4233 return non_lvalue (convert (type, arg0));
4235 /* In most languages, can't associate operations on floats
4236 through parentheses. Rather than remember where the parentheses
4237 were, we don't associate floats at all. It shouldn't matter much.
4238 However, associating multiplications is only very slightly
4239 inaccurate, so do that if -ffast-math is specified. */
4240 if (FLOAT_TYPE_P (type)
4241 && ! (flag_fast_math && code == MULT_EXPR))
4244 /* The varsign == -1 cases happen only for addition and subtraction.
4245 It says that the arg that was split was really CON minus VAR.
4246 The rest of the code applies to all associative operations. */
4252 if (split_tree (arg0, code, &var, &con, &varsign))
4256 /* EXPR is (CON-VAR) +- ARG1. */
4257 /* If it is + and VAR==ARG1, return just CONST. */
4258 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
4259 return convert (TREE_TYPE (t), con);
4261 /* If ARG0 is a constant, don't change things around;
4262 instead keep all the constant computations together. */
4264 if (TREE_CONSTANT (arg0))
4267 /* Otherwise return (CON +- ARG1) - VAR. */
4268 t = build (MINUS_EXPR, type,
4269 fold (build (code, type, con, arg1)), var);
4273 /* EXPR is (VAR+CON) +- ARG1. */
4274 /* If it is - and VAR==ARG1, return just CONST. */
4275 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
4276 return convert (TREE_TYPE (t), con);
4278 /* If ARG0 is a constant, don't change things around;
4279 instead keep all the constant computations together. */
4281 if (TREE_CONSTANT (arg0))
4284 /* Otherwise return VAR +- (ARG1 +- CON). */
4285 tem = fold (build (code, type, arg1, con));
4286 t = build (code, type, var, tem);
4288 if (integer_zerop (tem)
4289 && (code == PLUS_EXPR || code == MINUS_EXPR))
4290 return convert (type, var);
4291 /* If we have x +/- (c - d) [c an explicit integer]
4292 change it to x -/+ (d - c) since if d is relocatable
4293 then the latter can be a single immediate insn
4294 and the former cannot. */
4295 if (TREE_CODE (tem) == MINUS_EXPR
4296 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
4298 tree tem1 = TREE_OPERAND (tem, 1);
4299 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
4300 TREE_OPERAND (tem, 0) = tem1;
4302 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4308 if (split_tree (arg1, code, &var, &con, &varsign))
4310 if (TREE_CONSTANT (arg1))
4315 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
4317 /* EXPR is ARG0 +- (CON +- VAR). */
4318 if (TREE_CODE (t) == MINUS_EXPR
4319 && operand_equal_p (var, arg0, 0))
4321 /* If VAR and ARG0 cancel, return just CON or -CON. */
4322 if (code == PLUS_EXPR)
4323 return convert (TREE_TYPE (t), con);
4324 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
4325 convert (TREE_TYPE (t), con)));
4328 t = build (TREE_CODE (t), type,
4329 fold (build (code, TREE_TYPE (t), arg0, con)), var);
4331 if (integer_zerop (TREE_OPERAND (t, 0))
4332 && TREE_CODE (t) == PLUS_EXPR)
4333 return convert (TREE_TYPE (t), var);
4338 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
4339 if (TREE_CODE (arg1) == REAL_CST)
4341 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
4343 t1 = const_binop (code, arg0, arg1, 0);
4344 if (t1 != NULL_TREE)
4346 /* The return value should always have
4347 the same type as the original expression. */
4348 if (TREE_TYPE (t1) != TREE_TYPE (t))
4349 t1 = convert (TREE_TYPE (t), t1);
4356 if (! FLOAT_TYPE_P (type))
4358 if (! wins && integer_zerop (arg0))
4359 return build1 (NEGATE_EXPR, type, arg1);
4360 if (integer_zerop (arg1))
4361 return non_lvalue (convert (type, arg0));
4363 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
4364 about the case where C is a constant, just try one of the
4365 four possibilities. */
4367 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
4368 && operand_equal_p (TREE_OPERAND (arg0, 1),
4369 TREE_OPERAND (arg1, 1), 0))
4370 return fold (build (MULT_EXPR, type,
4371 fold (build (MINUS_EXPR, type,
4372 TREE_OPERAND (arg0, 0),
4373 TREE_OPERAND (arg1, 0))),
4374 TREE_OPERAND (arg0, 1)));
4376 /* Convert A - (-B) to A + B. */
4377 else if (TREE_CODE (arg1) == NEGATE_EXPR)
4378 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
4380 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4383 /* Except with IEEE floating point, 0-x equals -x. */
4384 if (! wins && real_zerop (arg0))
4385 return build1 (NEGATE_EXPR, type, arg1);
4386 /* Except with IEEE floating point, x-0 equals x. */
4387 if (real_zerop (arg1))
4388 return non_lvalue (convert (type, arg0));
4391 /* Fold &x - &x. This can happen from &x.foo - &x.
4392 This is unsafe for certain floats even in non-IEEE formats.
4393 In IEEE, it is unsafe because it does wrong for NaNs.
4394 Also note that operand_equal_p is always false if an operand
4397 if ((! FLOAT_TYPE_P (type) || flag_fast_math)
4398 && operand_equal_p (arg0, arg1, 0))
4399 return convert (type, integer_zero_node);
4404 if (! FLOAT_TYPE_P (type))
4406 if (integer_zerop (arg1))
4407 return omit_one_operand (type, arg1, arg0);
4408 if (integer_onep (arg1))
4409 return non_lvalue (convert (type, arg0));
4411 /* ((A / C) * C) is A if the division is an
4412 EXACT_DIV_EXPR. Since C is normally a constant,
4413 just check for one of the four possibilities. */
4415 if (TREE_CODE (arg0) == EXACT_DIV_EXPR
4416 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4417 return TREE_OPERAND (arg0, 0);
4419 /* (a * (1 << b)) is (a << b) */
4420 if (TREE_CODE (arg1) == LSHIFT_EXPR
4421 && integer_onep (TREE_OPERAND (arg1, 0)))
4422 return fold (build (LSHIFT_EXPR, type, arg0,
4423 TREE_OPERAND (arg1, 1)));
4424 if (TREE_CODE (arg0) == LSHIFT_EXPR
4425 && integer_onep (TREE_OPERAND (arg0, 0)))
4426 return fold (build (LSHIFT_EXPR, type, arg1,
4427 TREE_OPERAND (arg0, 1)));
4431 /* x*0 is 0, except for IEEE floating point. */
4432 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4434 && real_zerop (arg1))
4435 return omit_one_operand (type, arg1, arg0);
4436 /* In IEEE floating point, x*1 is not equivalent to x for snans.
4437 However, ANSI says we can drop signals,
4438 so we can do this anyway. */
4439 if (real_onep (arg1))
4440 return non_lvalue (convert (type, arg0));
4442 if (! wins && real_twop (arg1) && current_function_decl != 0)
4444 tree arg = save_expr (arg0);
4445 return build (PLUS_EXPR, type, arg, arg);
4453 register enum tree_code code0, code1;
4455 if (integer_all_onesp (arg1))
4456 return omit_one_operand (type, arg1, arg0);
4457 if (integer_zerop (arg1))
4458 return non_lvalue (convert (type, arg0));
4459 t1 = distribute_bit_expr (code, type, arg0, arg1);
4460 if (t1 != NULL_TREE)
4463 /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A
4464 is a rotate of A by C1 bits. */
4465 /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A
4466 is a rotate of A by B bits. */
4468 code0 = TREE_CODE (arg0);
4469 code1 = TREE_CODE (arg1);
4470 if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
4471 || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
4472 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
4473 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4475 register tree tree01, tree11;
4476 register enum tree_code code01, code11;
4478 tree01 = TREE_OPERAND (arg0, 1);
4479 tree11 = TREE_OPERAND (arg1, 1);
4480 code01 = TREE_CODE (tree01);
4481 code11 = TREE_CODE (tree11);
4482 if (code01 == INTEGER_CST
4483 && code11 == INTEGER_CST
4484 && TREE_INT_CST_HIGH (tree01) == 0
4485 && TREE_INT_CST_HIGH (tree11) == 0
4486 && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
4487 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
4488 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
4489 code0 == LSHIFT_EXPR ? tree01 : tree11);
4490 else if (code11 == MINUS_EXPR
4491 && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST
4492 && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0
4493 && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0))
4494 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4495 && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0))
4496 return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4497 type, TREE_OPERAND (arg0, 0), tree01);
4498 else if (code01 == MINUS_EXPR
4499 && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST
4500 && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0
4501 && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0))
4502 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))
4503 && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0))
4504 return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR,
4505 type, TREE_OPERAND (arg0, 0), tree11);
4512 if (integer_zerop (arg1))
4513 return non_lvalue (convert (type, arg0));
4514 if (integer_all_onesp (arg1))
4515 return fold (build1 (BIT_NOT_EXPR, type, arg0));
4520 if (integer_all_onesp (arg1))
4521 return non_lvalue (convert (type, arg0));
4522 if (integer_zerop (arg1))
4523 return omit_one_operand (type, arg1, arg0);
4524 t1 = distribute_bit_expr (code, type, arg0, arg1);
4525 if (t1 != NULL_TREE)
4527 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
4528 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
4529 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
4531 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
4532 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4533 && (~TREE_INT_CST_LOW (arg0)
4534 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4535 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
4537 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
4538 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4540 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
4541 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
4542 && (~TREE_INT_CST_LOW (arg1)
4543 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
4544 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
4548 case BIT_ANDTC_EXPR:
4549 if (integer_all_onesp (arg0))
4550 return non_lvalue (convert (type, arg1));
4551 if (integer_zerop (arg0))
4552 return omit_one_operand (type, arg0, arg1);
4553 if (TREE_CODE (arg1) == INTEGER_CST)
4555 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
4556 code = BIT_AND_EXPR;
4562 /* In most cases, do nothing with a divide by zero. */
4563 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4564 #ifndef REAL_INFINITY
4565 if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
4568 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4570 /* In IEEE floating point, x/1 is not equivalent to x for snans.
4571 However, ANSI says we can drop signals, so we can do this anyway. */
4572 if (real_onep (arg1))
4573 return non_lvalue (convert (type, arg0));
4575 /* If ARG1 is a constant, we can convert this to a multiply by the
4576 reciprocal. This does not have the same rounding properties,
4577 so only do this if -ffast-math. We can actually always safely
4578 do it if ARG1 is a power of two, but it's hard to tell if it is
4579 or not in a portable manner. */
4580 if (TREE_CODE (arg1) == REAL_CST)
4583 && 0 != (tem = const_binop (code, build_real (type, dconst1),
4585 return fold (build (MULT_EXPR, type, arg0, tem));
4586 /* Find the reciprocal if optimizing and the result is exact. */
4590 r = TREE_REAL_CST (arg1);
4591 if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
4593 tem = build_real (type, r);
4594 return fold (build (MULT_EXPR, type, arg0, tem));
4600 case TRUNC_DIV_EXPR:
4601 case ROUND_DIV_EXPR:
4602 case FLOOR_DIV_EXPR:
4604 case EXACT_DIV_EXPR:
4605 if (integer_onep (arg1))
4606 return non_lvalue (convert (type, arg0));
4607 if (integer_zerop (arg1))
4610 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
4611 operation, EXACT_DIV_EXPR.
4613 Note that only CEIL_DIV_EXPR is rewritten now, only because the
4614 others seem to be faster in some cases. This is probably just
4615 due to more work being done to optimize others in expmed.c than on
4617 if (code == CEIL_DIV_EXPR
4618 && multiple_of_p (type, arg0, arg1))
4619 return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
4621 /* If we have ((a / C1) / C2) where both division are the same type, try
4622 to simplify. First see if C1 * C2 overflows or not. */
4623 if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST
4624 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4628 new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0);
4629 tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0);
4631 if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem)
4632 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem))
4634 /* If no overflow, divide by C1*C2. */
4635 return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor));
4639 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
4640 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
4641 expressions, which often appear in the offsets or sizes of
4642 objects with a varying size. Only deal with positive divisors
4643 and multiplicands. If C2 is negative, we must have C2 % C3 == 0.
4645 Look for NOPs and SAVE_EXPRs inside. */
4647 if (TREE_CODE (arg1) == INTEGER_CST
4648 && tree_int_cst_sgn (arg1) >= 0)
4650 int have_save_expr = 0;
4651 tree c2 = integer_zero_node;
4654 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4655 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4659 if (TREE_CODE (xarg0) == PLUS_EXPR
4660 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4661 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4662 else if (TREE_CODE (xarg0) == MINUS_EXPR
4663 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4664 /* If we are doing this computation unsigned, the negate
4666 && ! TREE_UNSIGNED (type))
4668 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4669 xarg0 = TREE_OPERAND (xarg0, 0);
4672 if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0)
4673 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
4677 if (TREE_CODE (xarg0) == MULT_EXPR
4678 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4679 && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0
4680 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
4681 TREE_OPERAND (xarg0, 1), arg1, 1))
4682 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
4683 TREE_OPERAND (xarg0, 1), 1)))
4684 && (tree_int_cst_sgn (c2) >= 0
4685 || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2,
4688 tree outer_div = integer_one_node;
4689 tree c1 = TREE_OPERAND (xarg0, 1);
4692 /* If C3 > C1, set them equal and do a divide by
4693 C3/C1 at the end of the operation. */
4694 if (tree_int_cst_lt (c1, c3))
4695 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
4697 /* The result is A * (C1/C3) + (C2/C3). */
4698 t = fold (build (PLUS_EXPR, type,
4699 fold (build (MULT_EXPR, type,
4700 TREE_OPERAND (xarg0, 0),
4701 const_binop (code, c1, c3, 1))),
4702 const_binop (code, c2, c3, 1)));
4704 if (! integer_onep (outer_div))
4705 t = fold (build (code, type, t, convert (type, outer_div)));
4717 case FLOOR_MOD_EXPR:
4718 case ROUND_MOD_EXPR:
4719 case TRUNC_MOD_EXPR:
4720 if (integer_onep (arg1))
4721 return omit_one_operand (type, integer_zero_node, arg0);
4722 if (integer_zerop (arg1))
4725 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
4726 where C1 % C3 == 0. Handle similarly to the division case,
4727 but don't bother with SAVE_EXPRs. */
4729 if (TREE_CODE (arg1) == INTEGER_CST
4730 && ! integer_zerop (arg1))
4732 tree c2 = integer_zero_node;
4735 if (TREE_CODE (xarg0) == PLUS_EXPR
4736 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
4737 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
4738 else if (TREE_CODE (xarg0) == MINUS_EXPR
4739 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4740 && ! TREE_UNSIGNED (type))
4742 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
4743 xarg0 = TREE_OPERAND (xarg0, 0);
4748 if (TREE_CODE (xarg0) == MULT_EXPR
4749 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
4750 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
4751 TREE_OPERAND (xarg0, 1),
4753 && tree_int_cst_sgn (c2) >= 0)
4754 /* The result is (C2%C3). */
4755 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
4756 TREE_OPERAND (xarg0, 0));
4765 if (integer_zerop (arg1))
4766 return non_lvalue (convert (type, arg0));
4767 /* Since negative shift count is not well-defined,
4768 don't try to compute it in the compiler. */
4769 if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
4771 /* Rewrite an LROTATE_EXPR by a constant into an
4772 RROTATE_EXPR by a new constant. */
4773 if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
4775 TREE_SET_CODE (t, RROTATE_EXPR);
4776 code = RROTATE_EXPR;
4777 TREE_OPERAND (t, 1) = arg1
4780 convert (TREE_TYPE (arg1),
4781 build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
4783 if (tree_int_cst_sgn (arg1) < 0)
4787 /* If we have a rotate of a bit operation with the rotate count and
4788 the second operand of the bit operation both constant,
4789 permute the two operations. */
4790 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4791 && (TREE_CODE (arg0) == BIT_AND_EXPR
4792 || TREE_CODE (arg0) == BIT_ANDTC_EXPR
4793 || TREE_CODE (arg0) == BIT_IOR_EXPR
4794 || TREE_CODE (arg0) == BIT_XOR_EXPR)
4795 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
4796 return fold (build (TREE_CODE (arg0), type,
4797 fold (build (code, type,
4798 TREE_OPERAND (arg0, 0), arg1)),
4799 fold (build (code, type,
4800 TREE_OPERAND (arg0, 1), arg1))));
4802 /* Two consecutive rotates adding up to the width of the mode can
4804 if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
4805 && TREE_CODE (arg0) == RROTATE_EXPR
4806 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4807 && TREE_INT_CST_HIGH (arg1) == 0
4808 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
4809 && ((TREE_INT_CST_LOW (arg1)
4810 + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
4811 == GET_MODE_BITSIZE (TYPE_MODE (type))))
4812 return TREE_OPERAND (arg0, 0);
4817 if (operand_equal_p (arg0, arg1, 0))
4819 if (INTEGRAL_TYPE_P (type)
4820 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
4821 return omit_one_operand (type, arg1, arg0);
4825 if (operand_equal_p (arg0, arg1, 0))
4827 if (INTEGRAL_TYPE_P (type)
4828 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
4829 return omit_one_operand (type, arg1, arg0);
4832 case TRUTH_NOT_EXPR:
4833 /* Note that the operand of this must be an int
4834 and its values must be 0 or 1.
4835 ("true" is a fixed value perhaps depending on the language,
4836 but we don't handle values other than 1 correctly yet.) */
4837 tem = invert_truthvalue (arg0);
4838 /* Avoid infinite recursion. */
4839 if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
4841 return convert (type, tem);
4843 case TRUTH_ANDIF_EXPR:
4844 /* Note that the operands of this must be ints
4845 and their values must be 0 or 1.
4846 ("true" is a fixed value perhaps depending on the language.) */
4847 /* If first arg is constant zero, return it. */
4848 if (integer_zerop (arg0))
4850 case TRUTH_AND_EXPR:
4851 /* If either arg is constant true, drop it. */
4852 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4853 return non_lvalue (arg1);
4854 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4855 return non_lvalue (arg0);
4856 /* If second arg is constant zero, result is zero, but first arg
4857 must be evaluated. */
4858 if (integer_zerop (arg1))
4859 return omit_one_operand (type, arg1, arg0);
4860 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
4861 case will be handled here. */
4862 if (integer_zerop (arg0))
4863 return omit_one_operand (type, arg0, arg1);
4866 /* We only do these simplifications if we are optimizing. */
4870 /* Check for things like (A || B) && (A || C). We can convert this
4871 to A || (B && C). Note that either operator can be any of the four
4872 truth and/or operations and the transformation will still be
4873 valid. Also note that we only care about order for the
4874 ANDIF and ORIF operators. If B contains side effects, this
4875 might change the truth-value of A. */
4876 if (TREE_CODE (arg0) == TREE_CODE (arg1)
4877 && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
4878 || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
4879 || TREE_CODE (arg0) == TRUTH_AND_EXPR
4880 || TREE_CODE (arg0) == TRUTH_OR_EXPR)
4881 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
4883 tree a00 = TREE_OPERAND (arg0, 0);
4884 tree a01 = TREE_OPERAND (arg0, 1);
4885 tree a10 = TREE_OPERAND (arg1, 0);
4886 tree a11 = TREE_OPERAND (arg1, 1);
4887 int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
4888 || TREE_CODE (arg0) == TRUTH_AND_EXPR)
4889 && (code == TRUTH_AND_EXPR
4890 || code == TRUTH_OR_EXPR));
4892 if (operand_equal_p (a00, a10, 0))
4893 return fold (build (TREE_CODE (arg0), type, a00,
4894 fold (build (code, type, a01, a11))));
4895 else if (commutative && operand_equal_p (a00, a11, 0))
4896 return fold (build (TREE_CODE (arg0), type, a00,
4897 fold (build (code, type, a01, a10))));
4898 else if (commutative && operand_equal_p (a01, a10, 0))
4899 return fold (build (TREE_CODE (arg0), type, a01,
4900 fold (build (code, type, a00, a11))));
4902 /* This case if tricky because we must either have commutative
4903 operators or else A10 must not have side-effects. */
4905 else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
4906 && operand_equal_p (a01, a11, 0))
4907 return fold (build (TREE_CODE (arg0), type,
4908 fold (build (code, type, a00, a10)),
4912 /* See if we can build a range comparison. */
4913 if (0 != (tem = fold_range_test (t)))
4916 /* Check for the possibility of merging component references. If our
4917 lhs is another similar operation, try to merge its rhs with our
4918 rhs. Then try to merge our lhs and rhs. */
4919 if (TREE_CODE (arg0) == code
4920 && 0 != (tem = fold_truthop (code, type,
4921 TREE_OPERAND (arg0, 1), arg1)))
4922 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
4924 if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
4929 case TRUTH_ORIF_EXPR:
4930 /* Note that the operands of this must be ints
4931 and their values must be 0 or true.
4932 ("true" is a fixed value perhaps depending on the language.) */
4933 /* If first arg is constant true, return it. */
4934 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4937 /* If either arg is constant zero, drop it. */
4938 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
4939 return non_lvalue (arg1);
4940 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
4941 return non_lvalue (arg0);
4942 /* If second arg is constant true, result is true, but we must
4943 evaluate first arg. */
4944 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4945 return omit_one_operand (type, arg1, arg0);
4946 /* Likewise for first arg, but note this only occurs here for
4948 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4949 return omit_one_operand (type, arg0, arg1);
4952 case TRUTH_XOR_EXPR:
4953 /* If either arg is constant zero, drop it. */
4954 if (integer_zerop (arg0))
4955 return non_lvalue (arg1);
4956 if (integer_zerop (arg1))
4957 return non_lvalue (arg0);
4958 /* If either arg is constant true, this is a logical inversion. */
4959 if (integer_onep (arg0))
4960 return non_lvalue (invert_truthvalue (arg1));
4961 if (integer_onep (arg1))
4962 return non_lvalue (invert_truthvalue (arg0));
4971 /* If one arg is a constant integer, put it last. */
4972 if (TREE_CODE (arg0) == INTEGER_CST
4973 && TREE_CODE (arg1) != INTEGER_CST)
4975 TREE_OPERAND (t, 0) = arg1;
4976 TREE_OPERAND (t, 1) = arg0;
4977 arg0 = TREE_OPERAND (t, 0);
4978 arg1 = TREE_OPERAND (t, 1);
4979 code = swap_tree_comparison (code);
4980 TREE_SET_CODE (t, code);
4983 /* Convert foo++ == CONST into ++foo == CONST + INCR.
4984 First, see if one arg is constant; find the constant arg
4985 and the other one. */
4987 tree constop = 0, varop;
4988 int constopnum = -1;
4990 if (TREE_CONSTANT (arg1))
4991 constopnum = 1, constop = arg1, varop = arg0;
4992 if (TREE_CONSTANT (arg0))
4993 constopnum = 0, constop = arg0, varop = arg1;
4995 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
4997 /* This optimization is invalid for ordered comparisons
4998 if CONST+INCR overflows or if foo+incr might overflow.
4999 This optimization is invalid for floating point due to rounding.
5000 For pointer types we assume overflow doesn't happen. */
5001 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5002 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5003 && (code == EQ_EXPR || code == NE_EXPR)))
5006 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
5007 constop, TREE_OPERAND (varop, 1)));
5008 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
5010 /* If VAROP is a reference to a bitfield, we must mask
5011 the constant by the width of the field. */
5012 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5013 && DECL_BIT_FIELD(TREE_OPERAND
5014 (TREE_OPERAND (varop, 0), 1)))
5017 = TREE_INT_CST_LOW (DECL_SIZE
5019 (TREE_OPERAND (varop, 0), 1)));
5021 newconst = fold (build (BIT_AND_EXPR,
5022 TREE_TYPE (varop), newconst,
5023 convert (TREE_TYPE (varop),
5024 build_int_2 (size, 0))));
5028 t = build (code, type, TREE_OPERAND (t, 0),
5029 TREE_OPERAND (t, 1));
5030 TREE_OPERAND (t, constopnum) = newconst;
5034 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
5036 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
5037 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
5038 && (code == EQ_EXPR || code == NE_EXPR)))
5041 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
5042 constop, TREE_OPERAND (varop, 1)));
5043 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
5045 if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
5046 && DECL_BIT_FIELD(TREE_OPERAND
5047 (TREE_OPERAND (varop, 0), 1)))
5050 = TREE_INT_CST_LOW (DECL_SIZE
5052 (TREE_OPERAND (varop, 0), 1)));
5054 newconst = fold (build (BIT_AND_EXPR,
5055 TREE_TYPE (varop), newconst,
5056 convert (TREE_TYPE (varop),
5057 build_int_2 (size, 0))));
5061 t = build (code, type, TREE_OPERAND (t, 0),
5062 TREE_OPERAND (t, 1));
5063 TREE_OPERAND (t, constopnum) = newconst;
5069 /* Change X >= CST to X > (CST - 1) if CST is positive. */
5070 if (TREE_CODE (arg1) == INTEGER_CST
5071 && TREE_CODE (arg0) != INTEGER_CST
5072 && tree_int_cst_sgn (arg1) > 0)
5074 switch (TREE_CODE (t))
5078 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5079 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5084 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
5085 t = build (code, type, TREE_OPERAND (t, 0), arg1);
5090 /* If this is an EQ or NE comparison with zero and ARG0 is
5091 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
5092 two operations, but the latter can be done in one less insn
5093 one machine that have only two-operand insns or on which a
5094 constant cannot be the first operand. */
5095 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
5096 && TREE_CODE (arg0) == BIT_AND_EXPR)
5098 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
5099 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
5101 fold (build (code, type,
5102 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5104 TREE_TYPE (TREE_OPERAND (arg0, 0)),
5105 TREE_OPERAND (arg0, 1),
5106 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
5107 convert (TREE_TYPE (arg0),
5110 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
5111 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
5113 fold (build (code, type,
5114 build (BIT_AND_EXPR, TREE_TYPE (arg0),
5116 TREE_TYPE (TREE_OPERAND (arg0, 1)),
5117 TREE_OPERAND (arg0, 0),
5118 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
5119 convert (TREE_TYPE (arg0),
5124 /* If this is an NE or EQ comparison of zero against the result of a
5125 signed MOD operation whose second operand is a power of 2, make
5126 the MOD operation unsigned since it is simpler and equivalent. */
5127 if ((code == NE_EXPR || code == EQ_EXPR)
5128 && integer_zerop (arg1)
5129 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
5130 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
5131 || TREE_CODE (arg0) == CEIL_MOD_EXPR
5132 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
5133 || TREE_CODE (arg0) == ROUND_MOD_EXPR)
5134 && integer_pow2p (TREE_OPERAND (arg0, 1)))
5136 tree newtype = unsigned_type (TREE_TYPE (arg0));
5137 tree newmod = build (TREE_CODE (arg0), newtype,
5138 convert (newtype, TREE_OPERAND (arg0, 0)),
5139 convert (newtype, TREE_OPERAND (arg0, 1)));
5141 return build (code, type, newmod, convert (newtype, arg1));
5144 /* If this is an NE comparison of zero with an AND of one, remove the
5145 comparison since the AND will give the correct value. */
5146 if (code == NE_EXPR && integer_zerop (arg1)
5147 && TREE_CODE (arg0) == BIT_AND_EXPR
5148 && integer_onep (TREE_OPERAND (arg0, 1)))
5149 return convert (type, arg0);
5151 /* If we have (A & C) == C where C is a power of 2, convert this into
5152 (A & C) != 0. Similarly for NE_EXPR. */
5153 if ((code == EQ_EXPR || code == NE_EXPR)
5154 && TREE_CODE (arg0) == BIT_AND_EXPR
5155 && integer_pow2p (TREE_OPERAND (arg0, 1))
5156 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
5157 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
5158 arg0, integer_zero_node);
5160 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
5161 and similarly for >= into !=. */
5162 if ((code == LT_EXPR || code == GE_EXPR)
5163 && TREE_UNSIGNED (TREE_TYPE (arg0))
5164 && TREE_CODE (arg1) == LSHIFT_EXPR
5165 && integer_onep (TREE_OPERAND (arg1, 0)))
5166 return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5167 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5168 TREE_OPERAND (arg1, 1)),
5169 convert (TREE_TYPE (arg0), integer_zero_node));
5171 else if ((code == LT_EXPR || code == GE_EXPR)
5172 && TREE_UNSIGNED (TREE_TYPE (arg0))
5173 && (TREE_CODE (arg1) == NOP_EXPR
5174 || TREE_CODE (arg1) == CONVERT_EXPR)
5175 && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
5176 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
5178 build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
5179 convert (TREE_TYPE (arg0),
5180 build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
5181 TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
5182 convert (TREE_TYPE (arg0), integer_zero_node));
5184 /* Simplify comparison of something with itself. (For IEEE
5185 floating-point, we can only do some of these simplifications.) */
5186 if (operand_equal_p (arg0, arg1, 0))
5193 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5195 if (type == integer_type_node)
5196 return integer_one_node;
5198 t = build_int_2 (1, 0);
5199 TREE_TYPE (t) = type;
5203 TREE_SET_CODE (t, code);
5207 /* For NE, we can only do this simplification if integer. */
5208 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
5210 /* ... fall through ... */
5213 if (type == integer_type_node)
5214 return integer_zero_node;
5216 t = build_int_2 (0, 0);
5217 TREE_TYPE (t) = type;
5222 /* An unsigned comparison against 0 can be simplified. */
5223 if (integer_zerop (arg1)
5224 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
5225 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
5226 && TREE_UNSIGNED (TREE_TYPE (arg1)))
5228 switch (TREE_CODE (t))
5232 TREE_SET_CODE (t, NE_EXPR);
5236 TREE_SET_CODE (t, EQ_EXPR);
5239 return omit_one_operand (type,
5240 convert (type, integer_one_node),
5243 return omit_one_operand (type,
5244 convert (type, integer_zero_node),
5249 /* If we are comparing an expression that just has comparisons
5250 of two integer values, arithmetic expressions of those comparisons,
5251 and constants, we can simplify it. There are only three cases
5252 to check: the two values can either be equal, the first can be
5253 greater, or the second can be greater. Fold the expression for
5254 those three values. Since each value must be 0 or 1, we have
5255 eight possibilities, each of which corresponds to the constant 0
5256 or 1 or one of the six possible comparisons.
5258 This handles common cases like (a > b) == 0 but also handles
5259 expressions like ((x > y) - (y > x)) > 0, which supposedly
5260 occur in macroized code. */
5262 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
5264 tree cval1 = 0, cval2 = 0;
5267 if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
5268 /* Don't handle degenerate cases here; they should already
5269 have been handled anyway. */
5270 && cval1 != 0 && cval2 != 0
5271 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
5272 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
5273 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
5274 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
5275 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
5277 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
5278 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
5280 /* We can't just pass T to eval_subst in case cval1 or cval2
5281 was the same as ARG1. */
5284 = fold (build (code, type,
5285 eval_subst (arg0, cval1, maxval, cval2, minval),
5288 = fold (build (code, type,
5289 eval_subst (arg0, cval1, maxval, cval2, maxval),
5292 = fold (build (code, type,
5293 eval_subst (arg0, cval1, minval, cval2, maxval),
5296 /* All three of these results should be 0 or 1. Confirm they
5297 are. Then use those values to select the proper code
5300 if ((integer_zerop (high_result)
5301 || integer_onep (high_result))
5302 && (integer_zerop (equal_result)
5303 || integer_onep (equal_result))
5304 && (integer_zerop (low_result)
5305 || integer_onep (low_result)))
5307 /* Make a 3-bit mask with the high-order bit being the
5308 value for `>', the next for '=', and the low for '<'. */
5309 switch ((integer_onep (high_result) * 4)
5310 + (integer_onep (equal_result) * 2)
5311 + integer_onep (low_result))
5315 return omit_one_operand (type, integer_zero_node, arg0);
5336 return omit_one_operand (type, integer_one_node, arg0);
5339 t = build (code, type, cval1, cval2);
5341 return save_expr (t);
5348 /* If this is a comparison of a field, we may be able to simplify it. */
5349 if ((TREE_CODE (arg0) == COMPONENT_REF
5350 || TREE_CODE (arg0) == BIT_FIELD_REF)
5351 && (code == EQ_EXPR || code == NE_EXPR)
5352 /* Handle the constant case even without -O
5353 to make sure the warnings are given. */
5354 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
5356 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
5360 /* If this is a comparison of complex values and either or both
5361 sizes are a COMPLEX_EXPR, it is best to split up the comparisons
5362 and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This
5363 may prevent needless evaluations. */
5364 if ((code == EQ_EXPR || code == NE_EXPR)
5365 && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
5366 && (TREE_CODE (arg0) == COMPLEX_EXPR
5367 || TREE_CODE (arg1) == COMPLEX_EXPR))
5369 tree subtype = TREE_TYPE (TREE_TYPE (arg0));
5370 tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
5371 tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
5372 tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
5373 tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
5375 return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
5378 fold (build (code, type, real0, real1)),
5379 fold (build (code, type, imag0, imag1))));
5382 /* From here on, the only cases we handle are when the result is
5383 known to be a constant.
5385 To compute GT, swap the arguments and do LT.
5386 To compute GE, do LT and invert the result.
5387 To compute LE, swap the arguments, do LT and invert the result.
5388 To compute NE, do EQ and invert the result.
5390 Therefore, the code below must handle only EQ and LT. */
5392 if (code == LE_EXPR || code == GT_EXPR)
5394 tem = arg0, arg0 = arg1, arg1 = tem;
5395 code = swap_tree_comparison (code);
5398 /* Note that it is safe to invert for real values here because we
5399 will check below in the one case that it matters. */
5402 if (code == NE_EXPR || code == GE_EXPR)
5405 code = invert_tree_comparison (code);
5408 /* Compute a result for LT or EQ if args permit;
5409 otherwise return T. */
5410 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
5412 if (code == EQ_EXPR)
5413 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
5414 == TREE_INT_CST_LOW (arg1))
5415 && (TREE_INT_CST_HIGH (arg0)
5416 == TREE_INT_CST_HIGH (arg1)),
5419 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
5420 ? INT_CST_LT_UNSIGNED (arg0, arg1)
5421 : INT_CST_LT (arg0, arg1)),
5425 #if 0 /* This is no longer useful, but breaks some real code. */
5426 /* Assume a nonexplicit constant cannot equal an explicit one,
5427 since such code would be undefined anyway.
5428 Exception: on sysvr4, using #pragma weak,
5429 a label can come out as 0. */
5430 else if (TREE_CODE (arg1) == INTEGER_CST
5431 && !integer_zerop (arg1)
5432 && TREE_CONSTANT (arg0)
5433 && TREE_CODE (arg0) == ADDR_EXPR
5435 t1 = build_int_2 (0, 0);
5437 /* Two real constants can be compared explicitly. */
5438 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
5440 /* If either operand is a NaN, the result is false with two
5441 exceptions: First, an NE_EXPR is true on NaNs, but that case
5442 is already handled correctly since we will be inverting the
5443 result for NE_EXPR. Second, if we had inverted a LE_EXPR
5444 or a GE_EXPR into a LT_EXPR, we must return true so that it
5445 will be inverted into false. */
5447 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
5448 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
5449 t1 = build_int_2 (invert && code == LT_EXPR, 0);
5451 else if (code == EQ_EXPR)
5452 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
5453 TREE_REAL_CST (arg1)),
5456 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
5457 TREE_REAL_CST (arg1)),
5461 if (t1 == NULL_TREE)
5465 TREE_INT_CST_LOW (t1) ^= 1;
5467 TREE_TYPE (t1) = type;
5471 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
5472 so all simple results must be passed through pedantic_non_lvalue. */
5473 if (TREE_CODE (arg0) == INTEGER_CST)
5474 return pedantic_non_lvalue
5475 (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
5476 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
5477 return pedantic_omit_one_operand (type, arg1, arg0);
5479 /* If the second operand is zero, invert the comparison and swap
5480 the second and third operands. Likewise if the second operand
5481 is constant and the third is not or if the third operand is
5482 equivalent to the first operand of the comparison. */
5484 if (integer_zerop (arg1)
5485 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
5486 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5487 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5488 TREE_OPERAND (t, 2),
5489 TREE_OPERAND (arg0, 1))))
5491 /* See if this can be inverted. If it can't, possibly because
5492 it was a floating-point inequality comparison, don't do
5494 tem = invert_truthvalue (arg0);
5496 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5498 t = build (code, type, tem,
5499 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5501 arg1 = TREE_OPERAND (t, 2);
5506 /* If we have A op B ? A : C, we may be able to convert this to a
5507 simpler expression, depending on the operation and the values
5508 of B and C. IEEE floating point prevents this though,
5509 because A or B might be -0.0 or a NaN. */
5511 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
5512 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5513 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
5515 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
5516 arg1, TREE_OPERAND (arg0, 1)))
5518 tree arg2 = TREE_OPERAND (t, 2);
5519 enum tree_code comp_code = TREE_CODE (arg0);
5523 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
5524 depending on the comparison operation. */
5525 if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
5526 ? real_zerop (TREE_OPERAND (arg0, 1))
5527 : integer_zerop (TREE_OPERAND (arg0, 1)))
5528 && TREE_CODE (arg2) == NEGATE_EXPR
5529 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
5533 return pedantic_non_lvalue
5534 (fold (build1 (NEGATE_EXPR, type, arg1)));
5536 return pedantic_non_lvalue (convert (type, arg1));
5539 return pedantic_non_lvalue
5540 (convert (type, fold (build1 (ABS_EXPR,
5541 TREE_TYPE (arg1), arg1))));
5544 return pedantic_non_lvalue
5545 (fold (build1 (NEGATE_EXPR, type,
5547 fold (build1 (ABS_EXPR,
5552 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
5555 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
5557 if (comp_code == NE_EXPR)
5558 return pedantic_non_lvalue (convert (type, arg1));
5559 else if (comp_code == EQ_EXPR)
5560 return pedantic_non_lvalue (convert (type, integer_zero_node));
5563 /* If this is A op B ? A : B, this is either A, B, min (A, B),
5564 or max (A, B), depending on the operation. */
5566 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
5567 arg2, TREE_OPERAND (arg0, 0)))
5569 tree comp_op0 = TREE_OPERAND (arg0, 0);
5570 tree comp_op1 = TREE_OPERAND (arg0, 1);
5571 tree comp_type = TREE_TYPE (comp_op0);
5576 return pedantic_non_lvalue (convert (type, arg2));
5578 return pedantic_non_lvalue (convert (type, arg1));
5581 /* In C++ a ?: expression can be an lvalue, so we can't
5582 do this; we would lose the distinction between
5584 if (pedantic_lvalues)
5585 return pedantic_non_lvalue
5586 (convert (type, (fold (build (MIN_EXPR, comp_type,
5587 comp_op0, comp_op1)))));
5591 if (pedantic_lvalues)
5592 return pedantic_non_lvalue
5593 (convert (type, fold (build (MAX_EXPR, comp_type,
5594 comp_op0, comp_op1))));
5599 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5600 we might still be able to simplify this. For example,
5601 if C1 is one less or one more than C2, this might have started
5602 out as a MIN or MAX and been transformed by this function.
5603 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5605 if (INTEGRAL_TYPE_P (type)
5606 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
5607 && TREE_CODE (arg2) == INTEGER_CST)
5611 /* We can replace A with C1 in this case. */
5612 arg1 = convert (type, TREE_OPERAND (arg0, 1));
5613 t = build (code, type, TREE_OPERAND (t, 0), arg1,
5614 TREE_OPERAND (t, 2));
5618 /* If C1 is C2 + 1, this is min(A, C2). */
5619 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5620 && operand_equal_p (TREE_OPERAND (arg0, 1),
5621 const_binop (PLUS_EXPR, arg2,
5622 integer_one_node, 0), 1))
5623 return pedantic_non_lvalue
5624 (fold (build (MIN_EXPR, type, arg1, arg2)));
5628 /* If C1 is C2 - 1, this is min(A, C2). */
5629 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5630 && operand_equal_p (TREE_OPERAND (arg0, 1),
5631 const_binop (MINUS_EXPR, arg2,
5632 integer_one_node, 0), 1))
5633 return pedantic_non_lvalue
5634 (fold (build (MIN_EXPR, type, arg1, arg2)));
5638 /* If C1 is C2 - 1, this is max(A, C2). */
5639 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
5640 && operand_equal_p (TREE_OPERAND (arg0, 1),
5641 const_binop (MINUS_EXPR, arg2,
5642 integer_one_node, 0), 1))
5643 return pedantic_non_lvalue
5644 (fold (build (MAX_EXPR, type, arg1, arg2)));
5648 /* If C1 is C2 + 1, this is max(A, C2). */
5649 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
5650 && operand_equal_p (TREE_OPERAND (arg0, 1),
5651 const_binop (PLUS_EXPR, arg2,
5652 integer_one_node, 0), 1))
5653 return pedantic_non_lvalue
5654 (fold (build (MAX_EXPR, type, arg1, arg2)));
5659 /* If the second operand is simpler than the third, swap them
5660 since that produces better jump optimization results. */
5661 if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd'
5662 || TREE_CODE (arg1) == SAVE_EXPR)
5663 && ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
5664 || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd'
5665 || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
5667 /* See if this can be inverted. If it can't, possibly because
5668 it was a floating-point inequality comparison, don't do
5670 tem = invert_truthvalue (arg0);
5672 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
5674 t = build (code, type, tem,
5675 TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
5677 arg1 = TREE_OPERAND (t, 2);
5682 /* Convert A ? 1 : 0 to simply A. */
5683 if (integer_onep (TREE_OPERAND (t, 1))
5684 && integer_zerop (TREE_OPERAND (t, 2))
5685 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
5686 call to fold will try to move the conversion inside
5687 a COND, which will recurse. In that case, the COND_EXPR
5688 is probably the best choice, so leave it alone. */
5689 && type == TREE_TYPE (arg0))
5690 return pedantic_non_lvalue (arg0);
5692 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
5693 operation is simply A & 2. */
5695 if (integer_zerop (TREE_OPERAND (t, 2))
5696 && TREE_CODE (arg0) == NE_EXPR
5697 && integer_zerop (TREE_OPERAND (arg0, 1))
5698 && integer_pow2p (arg1)
5699 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
5700 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
5702 return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
5707 /* When pedantic, a compound expression can be neither an lvalue
5708 nor an integer constant expression. */
5709 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
5711 /* Don't let (0, 0) be null pointer constant. */
5712 if (integer_zerop (arg1))
5713 return non_lvalue (arg1);
5718 return build_complex (type, arg0, arg1);
5722 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5724 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5725 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
5726 TREE_OPERAND (arg0, 1));
5727 else if (TREE_CODE (arg0) == COMPLEX_CST)
5728 return TREE_REALPART (arg0);
5729 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5730 return fold (build (TREE_CODE (arg0), type,
5731 fold (build1 (REALPART_EXPR, type,
5732 TREE_OPERAND (arg0, 0))),
5733 fold (build1 (REALPART_EXPR,
5734 type, TREE_OPERAND (arg0, 1)))));
5738 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
5739 return convert (type, integer_zero_node);
5740 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
5741 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
5742 TREE_OPERAND (arg0, 0));
5743 else if (TREE_CODE (arg0) == COMPLEX_CST)
5744 return TREE_IMAGPART (arg0);
5745 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
5746 return fold (build (TREE_CODE (arg0), type,
5747 fold (build1 (IMAGPART_EXPR, type,
5748 TREE_OPERAND (arg0, 0))),
5749 fold (build1 (IMAGPART_EXPR, type,
5750 TREE_OPERAND (arg0, 1)))));
5753 /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
5755 case CLEANUP_POINT_EXPR:
5756 if (! TREE_SIDE_EFFECTS (arg0))
5757 return TREE_OPERAND (t, 0);
5760 enum tree_code code0 = TREE_CODE (arg0);
5761 int kind0 = TREE_CODE_CLASS (code0);
5762 tree arg00 = TREE_OPERAND (arg0, 0);
5765 if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
5766 return fold (build1 (code0, type,
5767 fold (build1 (CLEANUP_POINT_EXPR,
5768 TREE_TYPE (arg00), arg00))));
5770 if (kind0 == '<' || kind0 == '2'
5771 || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
5772 || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
5773 || code0 == TRUTH_XOR_EXPR)
5775 arg01 = TREE_OPERAND (arg0, 1);
5777 if (! TREE_SIDE_EFFECTS (arg00))
5778 return fold (build (code0, type, arg00,
5779 fold (build1 (CLEANUP_POINT_EXPR,
5780 TREE_TYPE (arg01), arg01))));
5782 if (! TREE_SIDE_EFFECTS (arg01))
5783 return fold (build (code0, type,
5784 fold (build1 (CLEANUP_POINT_EXPR,
5785 TREE_TYPE (arg00), arg00)),
5794 } /* switch (code) */
5797 /* Determine if first argument is a multiple of second argument.
5798 Return 0 if it is not, or is not easily determined to so be.
5800 An example of the sort of thing we care about (at this point --
5801 this routine could surely be made more general, and expanded
5802 to do what the *_DIV_EXPR's fold() cases do now) is discovering
5805 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5811 when we know that the two `SAVE_EXPR (J * 8)' nodes are the
5812 same node (which means they will have the same value at run
5813 time, even though we don't know when they'll be assigned).
5815 This code also handles discovering that
5817 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
5823 (of course) so we don't have to worry about dealing with a
5826 Note that we _look_ inside a SAVE_EXPR only to determine
5827 how it was calculated; it is not safe for fold() to do much
5828 of anything else with the internals of a SAVE_EXPR, since
5829 fold() cannot know when it will be evaluated at run time.
5830 For example, the latter example above _cannot_ be implemented
5835 or any variant thereof, since the value of J at evaluation time
5836 of the original SAVE_EXPR is not necessarily the same at the time
5837 the new expression is evaluated. The only optimization of this
5838 sort that would be valid is changing
5840 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
5846 SAVE_EXPR (I) * SAVE_EXPR (J)
5848 (where the same SAVE_EXPR (J) is used in the original and the
5849 transformed version). */
5852 multiple_of_p (type, top, bottom)
5857 if (operand_equal_p (top, bottom, 0))
5860 if (TREE_CODE (type) != INTEGER_TYPE)
5863 switch (TREE_CODE (top))
5866 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
5867 || multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
5871 return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
5872 && multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
5875 /* Punt if conversion from non-integral or wider integral type. */
5876 if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
5877 || (TYPE_PRECISION (type)
5878 < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
5882 return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
5885 if ((TREE_CODE (bottom) != INTEGER_CST)
5886 || (tree_int_cst_sgn (top) < 0)
5887 || (tree_int_cst_sgn (bottom) < 0))
5889 return integer_zerop (const_binop (TRUNC_MOD_EXPR,