1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992, 1993 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /*@@ Fix lossage on folding division of big integers. */
22 /*@@ This file should be rewritten to use an arbitrary precision
23 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
24 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
25 @@ The routines that translate from the ap rep should
26 @@ warn if precision et. al. is lost.
27 @@ This would also make life easier when this technology is used
28 @@ for cross-compilers. */
31 /* The entry points in this file are fold, size_int and 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'. */
48 /* Handle floating overflow for `const_binop'. */
49 static jmp_buf float_error;
51 static void encode PROTO((short *, HOST_WIDE_INT, HOST_WIDE_INT));
52 static void decode PROTO((short *, HOST_WIDE_INT *, HOST_WIDE_INT *));
53 static int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT,
54 HOST_WIDE_INT, HOST_WIDE_INT,
55 HOST_WIDE_INT, HOST_WIDE_INT *,
56 HOST_WIDE_INT *, HOST_WIDE_INT *,
58 static int split_tree PROTO((tree, enum tree_code, tree *, tree *, int *));
59 static tree const_binop PROTO((enum tree_code, tree, tree, int));
60 static tree fold_convert PROTO((tree, tree));
61 static enum tree_code invert_tree_comparison PROTO((enum tree_code));
62 static enum tree_code swap_tree_comparison PROTO((enum tree_code));
63 static int operand_equal_for_comparison_p PROTO((tree, tree, tree));
64 static int twoval_comparison_p PROTO((tree, tree *, tree *));
65 static tree eval_subst PROTO((tree, tree, tree, tree, tree));
66 static tree omit_one_operand PROTO((tree, tree, tree));
67 static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree));
68 static tree make_bit_field_ref PROTO((tree, tree, int, int, int));
69 static tree optimize_bit_field_compare PROTO((enum tree_code, tree,
71 static tree decode_field_reference PROTO((tree, int *, int *,
72 enum machine_mode *, int *,
74 static int all_ones_mask_p PROTO((tree, int));
75 static int simple_operand_p PROTO((tree));
76 static tree range_test PROTO((enum tree_code, tree, enum tree_code,
77 enum tree_code, tree, tree, tree));
78 static tree fold_truthop PROTO((enum tree_code, tree, tree, tree));
84 /* Yield nonzero if a signed left shift of A by B bits overflows. */
85 #define left_shift_overflows(a, b) ((a) != ((a) << (b)) >> (b))
87 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
88 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
89 Then this yields nonzero if overflow occurred during the addition.
90 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
91 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
92 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
94 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
95 We do that by representing the two-word integer as MAX_SHORTS shorts,
96 with only 8 bits stored in each short, as a positive number. */
98 /* Unpack a two-word integer into MAX_SHORTS shorts.
99 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
100 SHORTS points to the array of shorts. */
103 encode (shorts, low, hi)
105 HOST_WIDE_INT low, hi;
109 for (i = 0; i < MAX_SHORTS / 2; i++)
111 shorts[i] = (low >> (i * 8)) & 0xff;
112 shorts[i + MAX_SHORTS / 2] = (hi >> (i * 8) & 0xff);
116 /* Pack an array of MAX_SHORTS shorts into a two-word integer.
117 SHORTS points to the array of shorts.
118 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
121 decode (shorts, low, hi)
123 HOST_WIDE_INT *low, *hi;
126 HOST_WIDE_INT lv = 0, hv = 0;
128 for (i = 0; i < MAX_SHORTS / 2; i++)
130 lv |= (HOST_WIDE_INT) shorts[i] << (i * 8);
131 hv |= (HOST_WIDE_INT) shorts[i + MAX_SHORTS / 2] << (i * 8);
137 /* Make the integer constant T valid for its type
138 by setting to 0 or 1 all the bits in the constant
139 that don't belong in the type.
140 Yield 1 if a signed overflow occurs, 0 otherwise.
141 If OVERFLOW is nonzero, a signed overflow has already occurred
142 in calculating T, so propagate it. */
145 force_fit_type (t, overflow)
149 HOST_WIDE_INT low, high;
152 if (TREE_CODE (t) != INTEGER_CST)
155 low = TREE_INT_CST_LOW (t);
156 high = TREE_INT_CST_HIGH (t);
158 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
161 prec = TYPE_PRECISION (TREE_TYPE (t));
163 /* First clear all bits that are beyond the type's precision. */
165 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
167 else if (prec > HOST_BITS_PER_WIDE_INT)
169 TREE_INT_CST_HIGH (t)
170 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
174 TREE_INT_CST_HIGH (t) = 0;
175 if (prec < HOST_BITS_PER_WIDE_INT)
176 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
179 /* Unsigned types do not suffer sign extension or overflow. */
180 if (TREE_UNSIGNED (TREE_TYPE (t)))
183 /* If the value's sign bit is set, extend the sign. */
184 if (prec != 2 * HOST_BITS_PER_WIDE_INT
185 && (prec > HOST_BITS_PER_WIDE_INT
186 ? (TREE_INT_CST_HIGH (t)
187 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
188 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
190 /* Value is negative:
191 set to 1 all the bits that are outside this type's precision. */
192 if (prec > HOST_BITS_PER_WIDE_INT)
194 TREE_INT_CST_HIGH (t)
195 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
199 TREE_INT_CST_HIGH (t) = -1;
200 if (prec < HOST_BITS_PER_WIDE_INT)
201 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
205 /* Yield nonzero if signed overflow occurred. */
207 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
211 /* Add two doubleword integers with doubleword result.
212 Each argument is given as two `HOST_WIDE_INT' pieces.
213 One argument is L1 and H1; the other, L2 and H2.
214 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
215 We use the 8-shorts representation internally. */
218 add_double (l1, h1, l2, h2, lv, hv)
219 HOST_WIDE_INT l1, h1, l2, h2;
220 HOST_WIDE_INT *lv, *hv;
222 short arg1[MAX_SHORTS];
223 short arg2[MAX_SHORTS];
224 register int carry = 0;
227 encode (arg1, l1, h1);
228 encode (arg2, l2, h2);
230 for (i = 0; i < MAX_SHORTS; i++)
232 carry += arg1[i] + arg2[i];
233 arg1[i] = carry & 0xff;
237 decode (arg1, lv, hv);
238 return overflow_sum_sign (h1, h2, *hv);
241 /* Negate a doubleword integer with doubleword result.
242 Return nonzero if the operation overflows, assuming it's signed.
243 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
244 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
245 We use the 8-shorts representation internally. */
248 neg_double (l1, h1, lv, hv)
249 HOST_WIDE_INT l1, h1;
250 HOST_WIDE_INT *lv, *hv;
256 return (*hv & h1) < 0;
266 /* Multiply two doubleword integers with doubleword result.
267 Return nonzero if the operation overflows, assuming it's signed.
268 Each argument is given as two `HOST_WIDE_INT' pieces.
269 One argument is L1 and H1; the other, L2 and H2.
270 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
271 We use the 8-shorts representation internally. */
274 mul_double (l1, h1, l2, h2, lv, hv)
275 HOST_WIDE_INT l1, h1, l2, h2;
276 HOST_WIDE_INT *lv, *hv;
278 short arg1[MAX_SHORTS];
279 short arg2[MAX_SHORTS];
280 short prod[MAX_SHORTS * 2];
281 register int carry = 0;
282 register int i, j, k;
283 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
285 /* These cases are used extensively, arising from pointer combinations. */
290 int overflow = left_shift_overflows (h1, 1);
291 unsigned HOST_WIDE_INT temp = l1 + l1;
292 *hv = (h1 << 1) + (temp < l1);
298 int overflow = left_shift_overflows (h1, 2);
299 unsigned HOST_WIDE_INT temp = l1 + l1;
300 h1 = (h1 << 2) + ((temp < l1) << 1);
310 int overflow = left_shift_overflows (h1, 3);
311 unsigned HOST_WIDE_INT temp = l1 + l1;
312 h1 = (h1 << 3) + ((temp < l1) << 2);
315 h1 += (temp < l1) << 1;
325 encode (arg1, l1, h1);
326 encode (arg2, l2, h2);
328 bzero (prod, sizeof prod);
330 for (i = 0; i < MAX_SHORTS; i++)
331 for (j = 0; j < MAX_SHORTS; j++)
334 carry = arg1[i] * arg2[j];
338 prod[k] = carry & 0xff;
344 decode (prod, lv, hv); /* This ignores
345 prod[MAX_SHORTS] -> prod[MAX_SHORTS*2-1] */
347 /* Check for overflow by calculating the top half of the answer in full;
348 it should agree with the low half's sign bit. */
349 decode (prod+MAX_SHORTS, &toplow, &tophigh);
352 neg_double (l2, h2, &neglow, &neghigh);
353 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
357 neg_double (l1, h1, &neglow, &neghigh);
358 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
360 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
363 /* Shift the doubleword integer in L1, H1 left by COUNT places
364 keeping only PREC bits of result.
365 Shift right if COUNT is negative.
366 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
367 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
370 lshift_double (l1, h1, count, prec, lv, hv, arith)
371 HOST_WIDE_INT l1, h1, count;
373 HOST_WIDE_INT *lv, *hv;
376 short arg1[MAX_SHORTS];
382 rshift_double (l1, h1, - count, prec, lv, hv, arith);
386 encode (arg1, l1, h1);
394 for (i = 0; i < MAX_SHORTS; i++)
396 carry += arg1[i] << 1;
397 arg1[i] = carry & 0xff;
403 decode (arg1, lv, hv);
406 /* Shift the doubleword integer in L1, H1 right by COUNT places
407 keeping only PREC bits of result. COUNT must be positive.
408 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
409 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
412 rshift_double (l1, h1, count, prec, lv, hv, arith)
413 HOST_WIDE_INT l1, h1, count;
415 HOST_WIDE_INT *lv, *hv;
418 short arg1[MAX_SHORTS];
422 encode (arg1, l1, h1);
429 carry = arith && arg1[7] >> 7;
430 for (i = MAX_SHORTS - 1; i >= 0; i--)
434 arg1[i] = (carry >> 1) & 0xff;
439 decode (arg1, lv, hv);
442 /* Rotate the doubldword integer in L1, H1 left by COUNT places
443 keeping only PREC bits of result.
444 Rotate right if COUNT is negative.
445 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
448 lrotate_double (l1, h1, count, prec, lv, hv)
449 HOST_WIDE_INT l1, h1, count;
451 HOST_WIDE_INT *lv, *hv;
453 short arg1[MAX_SHORTS];
459 rrotate_double (l1, h1, - count, prec, lv, hv);
463 encode (arg1, l1, h1);
468 carry = arg1[MAX_SHORTS - 1] >> 7;
471 for (i = 0; i < MAX_SHORTS; i++)
473 carry += arg1[i] << 1;
474 arg1[i] = carry & 0xff;
480 decode (arg1, lv, hv);
483 /* Rotate the doubleword integer in L1, H1 left by COUNT places
484 keeping only PREC bits of result. COUNT must be positive.
485 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
488 rrotate_double (l1, h1, count, prec, lv, hv)
489 HOST_WIDE_INT l1, h1, count;
491 HOST_WIDE_INT *lv, *hv;
493 short arg1[MAX_SHORTS];
497 encode (arg1, l1, h1);
505 for (i = MAX_SHORTS - 1; i >= 0; i--)
509 arg1[i] = (carry >> 1) & 0xff;
514 decode (arg1, lv, hv);
517 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
518 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
519 CODE is a tree code for a kind of division, one of
520 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
522 It controls how the quotient is rounded to a integer.
523 Return nonzero if the operation overflows.
524 UNS nonzero says do unsigned division. */
527 div_and_round_double (code, uns,
528 lnum_orig, hnum_orig, lden_orig, hden_orig,
529 lquo, hquo, lrem, hrem)
532 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
533 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
534 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
537 short num[MAX_SHORTS + 1]; /* extra element for scaling. */
538 short den[MAX_SHORTS], quo[MAX_SHORTS];
539 register int i, j, work;
540 register int carry = 0;
541 HOST_WIDE_INT lnum = lnum_orig;
542 HOST_WIDE_INT hnum = hnum_orig;
543 HOST_WIDE_INT lden = lden_orig;
544 HOST_WIDE_INT hden = hden_orig;
547 if ((hden == 0) && (lden == 0))
550 /* calculate quotient sign and convert operands to unsigned. */
556 /* (minimum integer) / (-1) is the only overflow case. */
557 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
563 neg_double (lden, hden, &lden, &hden);
567 if (hnum == 0 && hden == 0)
568 { /* single precision */
570 /* This unsigned division rounds toward zero. */
571 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
576 { /* trivial case: dividend < divisor */
577 /* hden != 0 already checked. */
584 bzero (quo, sizeof quo);
586 bzero (num, sizeof num); /* to zero 9th element */
587 bzero (den, sizeof den);
589 encode (num, lnum, hnum);
590 encode (den, lden, hden);
592 /* This code requires more than just hden == 0.
593 We also have to require that we don't need more than three bytes
594 to hold CARRY. If we ever did need four bytes to hold it, we
595 would lose part of it when computing WORK on the next round. */
596 if (hden == 0 && (((unsigned HOST_WIDE_INT) lden << 8) >> 8) == lden)
597 { /* simpler algorithm */
598 /* hnum != 0 already checked. */
599 for (i = MAX_SHORTS - 1; i >= 0; i--)
601 work = num[i] + (carry << 8);
602 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
603 carry = work % (unsigned HOST_WIDE_INT) lden;
606 else { /* full double precision,
607 with thanks to Don Knuth's
608 "Seminumerical Algorithms". */
610 int quo_est, scale, num_hi_sig, den_hi_sig, quo_hi_sig;
612 /* Find the highest non-zero divisor digit. */
613 for (i = MAX_SHORTS - 1; ; i--)
618 for (i = MAX_SHORTS - 1; ; i--)
623 quo_hi_sig = num_hi_sig - den_hi_sig + 1;
625 /* Insure that the first digit of the divisor is at least BASE/2.
626 This is required by the quotient digit estimation algorithm. */
628 scale = BASE / (den[den_hi_sig] + 1);
629 if (scale > 1) { /* scale divisor and dividend */
631 for (i = 0; i <= MAX_SHORTS - 1; i++) {
632 work = (num[i] * scale) + carry;
633 num[i] = work & 0xff;
635 if (num[i] != 0) num_hi_sig = i;
638 for (i = 0; i <= MAX_SHORTS - 1; i++) {
639 work = (den[i] * scale) + carry;
640 den[i] = work & 0xff;
642 if (den[i] != 0) den_hi_sig = i;
647 for (i = quo_hi_sig; i > 0; i--) {
648 /* guess the next quotient digit, quo_est, by dividing the first
649 two remaining dividend digits by the high order quotient digit.
650 quo_est is never low and is at most 2 high. */
652 int num_hi; /* index of highest remaining dividend digit */
654 num_hi = i + den_hi_sig;
656 work = (num[num_hi] * BASE) + (num_hi > 0 ? num[num_hi - 1] : 0);
657 if (num[num_hi] != den[den_hi_sig]) {
658 quo_est = work / den[den_hi_sig];
664 /* refine quo_est so it's usually correct, and at most one high. */
665 while ((den[den_hi_sig - 1] * quo_est)
666 > (((work - (quo_est * den[den_hi_sig])) * BASE)
667 + ((num_hi - 1) > 0 ? num[num_hi - 2] : 0)))
670 /* Try QUO_EST as the quotient digit, by multiplying the
671 divisor by QUO_EST and subtracting from the remaining dividend.
672 Keep in mind that QUO_EST is the I - 1st digit. */
676 for (j = 0; j <= den_hi_sig; j++)
680 work = num[i + j - 1] - (quo_est * den[j]) + carry;
688 num[i + j - 1] = digit;
691 /* if quo_est was high by one, then num[i] went negative and
692 we need to correct things. */
697 carry = 0; /* add divisor back in */
698 for (j = 0; j <= den_hi_sig; j++)
700 work = num[i + j - 1] + den[j] + carry;
710 num[i + j - 1] = work;
712 num [num_hi] += carry;
715 /* store the quotient digit. */
716 quo[i - 1] = quo_est;
720 decode (quo, lquo, hquo);
723 /* if result is negative, make it so. */
725 neg_double (*lquo, *hquo, lquo, hquo);
727 /* compute trial remainder: rem = num - (quo * den) */
728 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
729 neg_double (*lrem, *hrem, lrem, hrem);
730 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
735 case TRUNC_MOD_EXPR: /* round toward zero */
736 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
740 case FLOOR_MOD_EXPR: /* round toward negative infinity */
741 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
744 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
747 else return overflow;
751 case CEIL_MOD_EXPR: /* round toward positive infinity */
752 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
754 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
757 else return overflow;
761 case ROUND_MOD_EXPR: /* round to closest integer */
763 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
764 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
766 /* get absolute values */
767 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
768 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
770 /* if (2 * abs (lrem) >= abs (lden)) */
771 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
772 labs_rem, habs_rem, <wice, &htwice);
773 if (((unsigned HOST_WIDE_INT) habs_den
774 < (unsigned HOST_WIDE_INT) htwice)
775 || (((unsigned HOST_WIDE_INT) habs_den
776 == (unsigned HOST_WIDE_INT) htwice)
777 && ((HOST_WIDE_INT unsigned) labs_den
778 < (unsigned HOST_WIDE_INT) ltwice)))
782 add_double (*lquo, *hquo,
783 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
786 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
789 else return overflow;
797 /* compute true remainder: rem = num - (quo * den) */
798 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
799 neg_double (*lrem, *hrem, lrem, hrem);
800 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
804 #ifndef REAL_ARITHMETIC
805 /* Effectively truncate a real value to represent
806 the nearest possible value in a narrower mode.
807 The result is actually represented in the same data type as the argument,
808 but its value is usually different. */
811 real_value_truncate (mode, arg)
812 enum machine_mode mode;
816 /* Make sure the value is actually stored in memory before we turn off
820 REAL_VALUE_TYPE value;
821 jmp_buf handler, old_handler;
824 if (setjmp (handler))
826 error ("floating overflow");
829 handled = push_float_handler (handler, old_handler);
830 value = REAL_VALUE_TRUNCATE (mode, arg);
831 pop_float_handler (handled, old_handler);
835 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
837 /* Check for infinity in an IEEE double precision number. */
843 /* The IEEE 64-bit double format. */
848 unsigned exponent : 11;
849 unsigned mantissa1 : 20;
854 unsigned mantissa1 : 20;
855 unsigned exponent : 11;
861 if (u.big_endian.sign == 1)
864 return (u.big_endian.exponent == 2047
865 && u.big_endian.mantissa1 == 0
866 && u.big_endian.mantissa2 == 0);
871 return (u.little_endian.exponent == 2047
872 && u.little_endian.mantissa1 == 0
873 && u.little_endian.mantissa2 == 0);
877 /* Check whether an IEEE double precision number is a NaN. */
883 /* The IEEE 64-bit double format. */
888 unsigned exponent : 11;
889 unsigned mantissa1 : 20;
894 unsigned mantissa1 : 20;
895 unsigned exponent : 11;
901 if (u.big_endian.sign == 1)
904 return (u.big_endian.exponent == 2047
905 && (u.big_endian.mantissa1 != 0
906 || u.big_endian.mantissa2 != 0));
911 return (u.little_endian.exponent == 2047
912 && (u.little_endian.mantissa1 != 0
913 || u.little_endian.mantissa2 != 0));
917 /* Check for a negative IEEE double precision number. */
923 /* The IEEE 64-bit double format. */
928 unsigned exponent : 11;
929 unsigned mantissa1 : 20;
934 unsigned mantissa1 : 20;
935 unsigned exponent : 11;
941 if (u.big_endian.sign == 1)
944 return u.big_endian.sign;
949 return u.little_endian.sign;
952 #else /* Target not IEEE */
954 /* Let's assume other float formats don't have infinity.
955 (This can be overridden by redefining REAL_VALUE_ISINF.) */
963 /* Let's assume other float formats don't have NaNs.
964 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
972 /* Let's assume other float formats don't have minus zero.
973 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
980 #endif /* Target not IEEE */
981 #endif /* no REAL_ARITHMETIC */
983 /* Split a tree IN into a constant and a variable part
984 that could be combined with CODE to make IN.
985 CODE must be a commutative arithmetic operation.
986 Store the constant part into *CONP and the variable in &VARP.
987 Return 1 if this was done; zero means the tree IN did not decompose
990 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
991 Therefore, we must tell the caller whether the variable part
992 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
993 The value stored is the coefficient for the variable term.
994 The constant term we return should always be added;
995 we negate it if necessary. */
998 split_tree (in, code, varp, conp, varsignp)
1000 enum tree_code code;
1004 register tree outtype = TREE_TYPE (in);
1008 /* Strip any conversions that don't change the machine mode. */
1009 while ((TREE_CODE (in) == NOP_EXPR
1010 || TREE_CODE (in) == CONVERT_EXPR)
1011 && (TYPE_MODE (TREE_TYPE (in))
1012 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
1013 in = TREE_OPERAND (in, 0);
1015 if (TREE_CODE (in) == code
1016 || (! FLOAT_TYPE_P (TREE_TYPE (in))
1017 /* We can associate addition and subtraction together
1018 (even though the C standard doesn't say so)
1019 for integers because the value is not affected.
1020 For reals, the value might be affected, so we can't. */
1021 && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
1022 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
1024 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1025 if (code == INTEGER_CST)
1027 *conp = TREE_OPERAND (in, 0);
1028 *varp = TREE_OPERAND (in, 1);
1029 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1030 && TREE_TYPE (*varp) != outtype)
1031 *varp = convert (outtype, *varp);
1032 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1035 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1037 *conp = TREE_OPERAND (in, 1);
1038 *varp = TREE_OPERAND (in, 0);
1040 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1041 && TREE_TYPE (*varp) != outtype)
1042 *varp = convert (outtype, *varp);
1043 if (TREE_CODE (in) == MINUS_EXPR)
1045 /* If operation is subtraction and constant is second,
1046 must negate it to get an additive constant.
1047 And this cannot be done unless it is a manifest constant.
1048 It could also be the address of a static variable.
1049 We cannot negate that, so give up. */
1050 if (TREE_CODE (*conp) == INTEGER_CST)
1051 /* Subtracting from integer_zero_node loses for long long. */
1052 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1058 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1060 *conp = TREE_OPERAND (in, 0);
1061 *varp = TREE_OPERAND (in, 1);
1062 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1063 && TREE_TYPE (*varp) != outtype)
1064 *varp = convert (outtype, *varp);
1065 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1072 /* Combine two constants NUM and ARG2 under operation CODE
1073 to produce a new constant.
1074 We assume ARG1 and ARG2 have the same data type,
1075 or at least are the same kind of constant and the same machine mode.
1077 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1080 const_binop (code, arg1, arg2, notrunc)
1081 enum tree_code code;
1082 register tree arg1, arg2;
1085 if (TREE_CODE (arg1) == INTEGER_CST)
1087 register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1);
1088 register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1);
1089 HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2);
1090 HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2);
1091 HOST_WIDE_INT low, hi;
1092 HOST_WIDE_INT garbagel, garbageh;
1094 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1100 t = build_int_2 (int1l | int2l, int1h | int2h);
1104 t = build_int_2 (int1l ^ int2l, int1h ^ int2h);
1108 t = build_int_2 (int1l & int2l, int1h & int2h);
1111 case BIT_ANDTC_EXPR:
1112 t = build_int_2 (int1l & ~int2l, int1h & ~int2h);
1118 /* It's unclear from the C standard whether shifts can overflow.
1119 The following code ignores overflow; perhaps a C standard
1120 interpretation ruling is needed. */
1121 lshift_double (int1l, int1h, int2l,
1122 TYPE_PRECISION (TREE_TYPE (arg1)),
1125 t = build_int_2 (low, hi);
1126 TREE_TYPE (t) = TREE_TYPE (arg1);
1128 force_fit_type (t, 0);
1129 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2);
1130 TREE_CONSTANT_OVERFLOW (t)
1131 = TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2);
1137 lrotate_double (int1l, int1h, int2l,
1138 TYPE_PRECISION (TREE_TYPE (arg1)),
1140 t = build_int_2 (low, hi);
1147 if ((unsigned HOST_WIDE_INT) int2l < int1l)
1150 overflow = int2h < hi;
1152 t = build_int_2 (int2l, int2h);
1158 if ((unsigned HOST_WIDE_INT) int1l < int2l)
1161 overflow = int1h < hi;
1163 t = build_int_2 (int1l, int1h);
1166 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1167 t = build_int_2 (low, hi);
1171 if (int2h == 0 && int2l == 0)
1173 t = build_int_2 (int1l, int1h);
1176 neg_double (int2l, int2h, &low, &hi);
1177 add_double (int1l, int1h, low, hi, &low, &hi);
1178 overflow = overflow_sum_sign (hi, int2h, int1h);
1179 t = build_int_2 (low, hi);
1183 /* Optimize simple cases. */
1186 unsigned HOST_WIDE_INT temp;
1191 t = build_int_2 (0, 0);
1194 t = build_int_2 (int2l, int2h);
1197 overflow = left_shift_overflows (int2h, 1);
1198 temp = int2l + int2l;
1199 int2h = (int2h << 1) + (temp < int2l);
1200 t = build_int_2 (temp, int2h);
1202 #if 0 /* This code can lose carries. */
1204 temp = int2l + int2l + int2l;
1205 int2h = int2h * 3 + (temp < int2l);
1206 t = build_int_2 (temp, int2h);
1210 overflow = left_shift_overflows (int2h, 2);
1211 temp = int2l + int2l;
1212 int2h = (int2h << 2) + ((temp < int2l) << 1);
1215 int2h += (temp < int2l);
1216 t = build_int_2 (temp, int2h);
1219 overflow = left_shift_overflows (int2h, 3);
1220 temp = int2l + int2l;
1221 int2h = (int2h << 3) + ((temp < int2l) << 2);
1224 int2h += (temp < int2l) << 1;
1227 int2h += (temp < int2l);
1228 t = build_int_2 (temp, int2h);
1239 t = build_int_2 (0, 0);
1244 t = build_int_2 (int1l, int1h);
1249 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1250 t = build_int_2 (low, hi);
1253 case TRUNC_DIV_EXPR:
1254 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1255 case EXACT_DIV_EXPR:
1256 /* This is a shortcut for a common special case.
1257 It reduces the number of tree nodes generated
1259 if (int2h == 0 && int2l > 0
1260 && TREE_TYPE (arg1) == sizetype
1261 && int1h == 0 && int1l >= 0)
1263 if (code == CEIL_DIV_EXPR)
1265 return size_int (int1l / int2l);
1267 case ROUND_DIV_EXPR:
1268 if (int2h == 0 && int2l == 1)
1270 t = build_int_2 (int1l, int1h);
1273 if (int1l == int2l && int1h == int2h)
1275 if ((int1l | int1h) == 0)
1277 t = build_int_2 (1, 0);
1280 overflow = div_and_round_double (code, uns,
1281 int1l, int1h, int2l, int2h,
1282 &low, &hi, &garbagel, &garbageh);
1283 t = build_int_2 (low, hi);
1286 case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR:
1287 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1288 overflow = div_and_round_double (code, uns,
1289 int1l, int1h, int2l, int2h,
1290 &garbagel, &garbageh, &low, &hi);
1291 t = build_int_2 (low, hi);
1298 low = (((unsigned HOST_WIDE_INT) int1h
1299 < (unsigned HOST_WIDE_INT) int2h)
1300 || (((unsigned HOST_WIDE_INT) int1h
1301 == (unsigned HOST_WIDE_INT) int2h)
1302 && ((unsigned HOST_WIDE_INT) int1l
1303 < (unsigned HOST_WIDE_INT) int2l)));
1307 low = ((int1h < int2h)
1308 || ((int1h == int2h)
1309 && ((unsigned HOST_WIDE_INT) int1l
1310 < (unsigned HOST_WIDE_INT) int2l)));
1312 if (low == (code == MIN_EXPR))
1313 t = build_int_2 (int1l, int1h);
1315 t = build_int_2 (int2l, int2h);
1322 TREE_TYPE (t) = TREE_TYPE (arg1);
1324 = ((notrunc ? !uns && overflow : force_fit_type (t, overflow))
1325 | TREE_OVERFLOW (arg1)
1326 | TREE_OVERFLOW (arg2));
1327 TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
1328 | TREE_CONSTANT_OVERFLOW (arg1)
1329 | TREE_CONSTANT_OVERFLOW (arg2));
1332 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1333 if (TREE_CODE (arg1) == REAL_CST)
1337 REAL_VALUE_TYPE value;
1340 d1 = TREE_REAL_CST (arg1);
1341 d2 = TREE_REAL_CST (arg2);
1342 if (setjmp (float_error))
1344 pedwarn ("floating overflow in constant expression");
1345 return build (code, TREE_TYPE (arg1), arg1, arg2);
1347 set_float_handler (float_error);
1349 #ifdef REAL_ARITHMETIC
1350 REAL_ARITHMETIC (value, code, d1, d2);
1367 #ifndef REAL_INFINITY
1376 value = MIN (d1, d2);
1380 value = MAX (d1, d2);
1386 #endif /* no REAL_ARITHMETIC */
1387 t = build_real (TREE_TYPE (arg1),
1388 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1389 set_float_handler (NULL_PTR);
1392 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1393 if (TREE_CODE (arg1) == COMPLEX_CST)
1395 register tree r1 = TREE_REALPART (arg1);
1396 register tree i1 = TREE_IMAGPART (arg1);
1397 register tree r2 = TREE_REALPART (arg2);
1398 register tree i2 = TREE_IMAGPART (arg2);
1404 t = build_complex (const_binop (PLUS_EXPR, r1, r2, notrunc),
1405 const_binop (PLUS_EXPR, i1, i2, notrunc));
1409 t = build_complex (const_binop (MINUS_EXPR, r1, r2, notrunc),
1410 const_binop (MINUS_EXPR, i1, i2, notrunc));
1414 t = build_complex (const_binop (MINUS_EXPR,
1415 const_binop (MULT_EXPR,
1417 const_binop (MULT_EXPR,
1420 const_binop (PLUS_EXPR,
1421 const_binop (MULT_EXPR,
1423 const_binop (MULT_EXPR,
1430 register tree magsquared
1431 = const_binop (PLUS_EXPR,
1432 const_binop (MULT_EXPR, r2, r2, notrunc),
1433 const_binop (MULT_EXPR, i2, i2, notrunc),
1435 t = build_complex (const_binop (RDIV_EXPR,
1436 const_binop (PLUS_EXPR,
1437 const_binop (MULT_EXPR, r1, r2, notrunc),
1438 const_binop (MULT_EXPR, i1, i2, notrunc),
1440 magsquared, notrunc),
1441 const_binop (RDIV_EXPR,
1442 const_binop (MINUS_EXPR,
1443 const_binop (MULT_EXPR, i1, r2, notrunc),
1444 const_binop (MULT_EXPR, r1, i2, notrunc),
1446 magsquared, notrunc));
1453 TREE_TYPE (t) = TREE_TYPE (arg1);
1459 /* Return an INTEGER_CST with value V and type from `sizetype'. */
1463 unsigned int number;
1466 /* Type-size nodes already made for small sizes. */
1467 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1469 if (number < 2*HOST_BITS_PER_WIDE_INT + 1
1470 && size_table[number] != 0)
1471 return size_table[number];
1472 if (number < 2*HOST_BITS_PER_WIDE_INT + 1)
1474 push_obstacks_nochange ();
1475 /* Make this a permanent node. */
1476 end_temporary_allocation ();
1477 t = build_int_2 (number, 0);
1478 TREE_TYPE (t) = sizetype;
1479 size_table[number] = t;
1484 t = build_int_2 (number, 0);
1485 TREE_TYPE (t) = sizetype;
1490 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1491 CODE is a tree code. Data type is taken from `sizetype',
1492 If the operands are constant, so is the result. */
1495 size_binop (code, arg0, arg1)
1496 enum tree_code code;
1499 /* Handle the special case of two integer constants faster. */
1500 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1502 /* And some specific cases even faster than that. */
1503 if (code == PLUS_EXPR
1504 && TREE_INT_CST_LOW (arg0) == 0
1505 && TREE_INT_CST_HIGH (arg0) == 0)
1507 if (code == MINUS_EXPR
1508 && TREE_INT_CST_LOW (arg1) == 0
1509 && TREE_INT_CST_HIGH (arg1) == 0)
1511 if (code == MULT_EXPR
1512 && TREE_INT_CST_LOW (arg0) == 1
1513 && TREE_INT_CST_HIGH (arg0) == 0)
1515 /* Handle general case of two integer constants. */
1516 return const_binop (code, arg0, arg1, 1);
1519 if (arg0 == error_mark_node || arg1 == error_mark_node)
1520 return error_mark_node;
1522 return fold (build (code, sizetype, arg0, arg1));
1525 /* Given T, a tree representing type conversion of ARG1, a constant,
1526 return a constant tree representing the result of conversion. */
1529 fold_convert (t, arg1)
1533 register tree type = TREE_TYPE (t);
1535 if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type))
1537 if (TREE_CODE (arg1) == INTEGER_CST)
1539 /* Given an integer constant, make new constant with new type,
1540 appropriately sign-extended or truncated. */
1541 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1542 TREE_INT_CST_HIGH (arg1));
1543 TREE_TYPE (t) = type;
1544 /* Indicate an overflow if (1) ARG1 already overflowed,
1545 or (2) force_fit_type indicates an overflow.
1546 Tell force_fit_type that an overflow has already occurred
1547 if ARG1 is a too-large unsigned value and T is signed. */
1549 = (TREE_OVERFLOW (arg1)
1550 | force_fit_type (t,
1551 (TREE_INT_CST_HIGH (arg1) < 0
1552 & (TREE_UNSIGNED (type)
1553 < TREE_UNSIGNED (TREE_TYPE (arg1))))));
1554 TREE_CONSTANT_OVERFLOW (t)
1555 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
1557 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1558 else if (TREE_CODE (arg1) == REAL_CST)
1560 REAL_VALUE_TYPE l, x, u;
1562 l = real_value_from_int_cst (TYPE_MIN_VALUE (type));
1563 x = TREE_REAL_CST (arg1);
1564 u = real_value_from_int_cst (TYPE_MAX_VALUE (type));
1566 /* See if X will be in range after truncation towards 0.
1567 To compensate for truncation, move the bounds away from 0,
1568 but reject if X exactly equals the adjusted bounds. */
1569 #ifdef REAL_ARITHMETIC
1570 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1571 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1576 if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
1578 pedwarn ("real constant out of range for integer conversion");
1581 #ifndef REAL_ARITHMETIC
1584 HOST_WIDE_INT low, high;
1585 HOST_WIDE_INT half_word
1586 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1588 d = TREE_REAL_CST (arg1);
1592 high = (HOST_WIDE_INT) (d / half_word / half_word);
1593 d -= (REAL_VALUE_TYPE) high * half_word * half_word;
1594 if (d >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1596 low = d - (REAL_VALUE_TYPE) half_word * half_word / 2;
1597 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1600 low = (HOST_WIDE_INT) d;
1601 if (TREE_REAL_CST (arg1) < 0)
1602 neg_double (low, high, &low, &high);
1603 t = build_int_2 (low, high);
1607 HOST_WIDE_INT low, high;
1608 REAL_VALUE_TO_INT (&low, &high, (TREE_REAL_CST (arg1)));
1609 t = build_int_2 (low, high);
1612 TREE_TYPE (t) = type;
1613 force_fit_type (t, 0);
1615 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1616 TREE_TYPE (t) = type;
1618 else if (TREE_CODE (type) == REAL_TYPE)
1620 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1621 if (TREE_CODE (arg1) == INTEGER_CST)
1622 return build_real_from_int_cst (type, arg1);
1623 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1624 if (TREE_CODE (arg1) == REAL_CST)
1626 if (setjmp (float_error))
1628 pedwarn ("floating overflow in constant expression");
1631 set_float_handler (float_error);
1633 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1634 TREE_REAL_CST (arg1)));
1635 set_float_handler (NULL_PTR);
1639 TREE_CONSTANT (t) = 1;
1643 /* Return an expr equal to X but certainly not valid as an lvalue.
1644 Also make sure it is not valid as an null pointer constant. */
1652 /* These things are certainly not lvalues. */
1653 if (TREE_CODE (x) == NON_LVALUE_EXPR
1654 || TREE_CODE (x) == INTEGER_CST
1655 || TREE_CODE (x) == REAL_CST
1656 || TREE_CODE (x) == STRING_CST
1657 || TREE_CODE (x) == ADDR_EXPR)
1659 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1661 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1662 so convert_for_assignment won't strip it.
1663 This is so this 0 won't be treated as a null pointer constant. */
1664 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1665 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1671 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1672 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1676 /* Given a tree comparison code, return the code that is the logical inverse
1677 of the given code. It is not safe to do this for floating-point
1678 comparisons, except for NE_EXPR and EQ_EXPR. */
1680 static enum tree_code
1681 invert_tree_comparison (code)
1682 enum tree_code code;
1703 /* Similar, but return the comparison that results if the operands are
1704 swapped. This is safe for floating-point. */
1706 static enum tree_code
1707 swap_tree_comparison (code)
1708 enum tree_code code;
1728 /* Return nonzero if two operands are necessarily equal.
1729 If ONLY_CONST is non-zero, only return non-zero for constants.
1730 This function tests whether the operands are indistinguishable;
1731 it does not test whether they are equal using C's == operation.
1732 The distinction is important for IEEE floating point, because
1733 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1734 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1737 operand_equal_p (arg0, arg1, only_const)
1741 /* If both types don't have the same signedness, then we can't consider
1742 them equal. We must check this before the STRIP_NOPS calls
1743 because they may change the signedness of the arguments. */
1744 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1750 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1751 We don't care about side effects in that case because the SAVE_EXPR
1752 takes care of that for us. */
1753 if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1)
1754 return ! only_const;
1756 if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))
1759 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1760 && TREE_CODE (arg0) == ADDR_EXPR
1761 && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0))
1764 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1765 && TREE_CODE (arg0) == INTEGER_CST
1766 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1767 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1))
1770 /* Detect when real constants are equal. */
1771 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1772 && TREE_CODE (arg0) == REAL_CST)
1773 return !bcmp (&TREE_REAL_CST (arg0), &TREE_REAL_CST (arg1),
1774 sizeof (REAL_VALUE_TYPE));
1782 if (TREE_CODE (arg0) != TREE_CODE (arg1))
1784 /* This is needed for conversions and for COMPONENT_REF.
1785 Might as well play it safe and always test this. */
1786 if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1789 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1792 /* Two conversions are equal only if signedness and modes match. */
1793 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1794 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1795 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1798 return operand_equal_p (TREE_OPERAND (arg0, 0),
1799 TREE_OPERAND (arg1, 0), 0);
1803 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1804 TREE_OPERAND (arg1, 0), 0)
1805 && operand_equal_p (TREE_OPERAND (arg0, 1),
1806 TREE_OPERAND (arg1, 1), 0));
1809 switch (TREE_CODE (arg0))
1812 return operand_equal_p (TREE_OPERAND (arg0, 0),
1813 TREE_OPERAND (arg1, 0), 0);
1817 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1818 TREE_OPERAND (arg1, 0), 0)
1819 && operand_equal_p (TREE_OPERAND (arg0, 1),
1820 TREE_OPERAND (arg1, 1), 0));
1823 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1824 TREE_OPERAND (arg1, 0), 0)
1825 && operand_equal_p (TREE_OPERAND (arg0, 1),
1826 TREE_OPERAND (arg1, 1), 0)
1827 && operand_equal_p (TREE_OPERAND (arg0, 2),
1828 TREE_OPERAND (arg1, 2), 0));
1836 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1837 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1839 When in doubt, return 0. */
1842 operand_equal_for_comparison_p (arg0, arg1, other)
1846 int unsignedp1, unsignedpo;
1847 tree primarg1, primother;
1850 if (operand_equal_p (arg0, arg1, 0))
1853 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
1856 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1857 actual comparison operand, ARG0.
1859 First throw away any conversions to wider types
1860 already present in the operands. */
1862 primarg1 = get_narrower (arg1, &unsignedp1);
1863 primother = get_narrower (other, &unsignedpo);
1865 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1866 if (unsignedp1 == unsignedpo
1867 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1868 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1870 tree type = TREE_TYPE (arg0);
1872 /* Make sure shorter operand is extended the right way
1873 to match the longer operand. */
1874 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1875 TREE_TYPE (primarg1)),
1878 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1885 /* See if ARG is an expression that is either a comparison or is performing
1886 arithmetic on comparisons. The comparisons must only be comparing
1887 two different values, which will be stored in *CVAL1 and *CVAL2; if
1888 they are non-zero it means that some operands have already been found.
1889 No variables may be used anywhere else in the expression except in the
1892 If this is true, return 1. Otherwise, return zero. */
1895 twoval_comparison_p (arg, cval1, cval2)
1897 tree *cval1, *cval2;
1899 enum tree_code code = TREE_CODE (arg);
1900 char class = TREE_CODE_CLASS (code);
1902 /* We can handle some of the 'e' cases here. */
1904 && (code == TRUTH_NOT_EXPR
1905 || (code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)))
1907 else if (class == 'e'
1908 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1909 || code == COMPOUND_EXPR))
1915 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2);
1918 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
1919 && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2));
1925 if (code == COND_EXPR)
1926 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
1927 && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2)
1928 && twoval_comparison_p (TREE_OPERAND (arg, 2),
1933 /* First see if we can handle the first operand, then the second. For
1934 the second operand, we know *CVAL1 can't be zero. It must be that
1935 one side of the comparison is each of the values; test for the
1936 case where this isn't true by failing if the two operands
1939 if (operand_equal_p (TREE_OPERAND (arg, 0),
1940 TREE_OPERAND (arg, 1), 0))
1944 *cval1 = TREE_OPERAND (arg, 0);
1945 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
1947 else if (*cval2 == 0)
1948 *cval2 = TREE_OPERAND (arg, 0);
1949 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
1954 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
1956 else if (*cval2 == 0)
1957 *cval2 = TREE_OPERAND (arg, 1);
1958 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
1969 /* ARG is a tree that is known to contain just arithmetic operations and
1970 comparisons. Evaluate the operations in the tree substituting NEW0 for
1971 any occurrence of OLD0 as an operand of a comparison and likewise for
1975 eval_subst (arg, old0, new0, old1, new1)
1977 tree old0, new0, old1, new1;
1979 tree type = TREE_TYPE (arg);
1980 enum tree_code code = TREE_CODE (arg);
1981 char class = TREE_CODE_CLASS (code);
1983 /* We can handle some of the 'e' cases here. */
1984 if (class == 'e' && code == TRUTH_NOT_EXPR)
1986 else if (class == 'e'
1987 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
1993 return fold (build1 (code, type,
1994 eval_subst (TREE_OPERAND (arg, 0),
1995 old0, new0, old1, new1)));
1998 return fold (build (code, type,
1999 eval_subst (TREE_OPERAND (arg, 0),
2000 old0, new0, old1, new1),
2001 eval_subst (TREE_OPERAND (arg, 1),
2002 old0, new0, old1, new1)));
2008 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
2011 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
2014 return fold (build (code, type,
2015 eval_subst (TREE_OPERAND (arg, 0),
2016 old0, new0, old1, new1),
2017 eval_subst (TREE_OPERAND (arg, 1),
2018 old0, new0, old1, new1),
2019 eval_subst (TREE_OPERAND (arg, 2),
2020 old0, new0, old1, new1)));
2025 tree arg0 = TREE_OPERAND (arg, 0);
2026 tree arg1 = TREE_OPERAND (arg, 1);
2028 /* We need to check both for exact equality and tree equality. The
2029 former will be true if the operand has a side-effect. In that
2030 case, we know the operand occurred exactly once. */
2032 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2034 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2037 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2039 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2042 return fold (build (code, type, arg0, arg1));
2049 /* Return a tree for the case when the result of an expression is RESULT
2050 converted to TYPE and OMITTED was previously an operand of the expression
2051 but is now not needed (e.g., we folded OMITTED * 0).
2053 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2054 the conversion of RESULT to TYPE. */
2057 omit_one_operand (type, result, omitted)
2058 tree type, result, omitted;
2060 tree t = convert (type, result);
2062 if (TREE_SIDE_EFFECTS (omitted))
2063 return build (COMPOUND_EXPR, type, omitted, t);
2065 return non_lvalue (t);
2068 /* Return a simplified tree node for the truth-negation of ARG. This
2069 never alters ARG itself. We assume that ARG is an operation that
2070 returns a truth value (0 or 1). */
2073 invert_truthvalue (arg)
2076 tree type = TREE_TYPE (arg);
2077 enum tree_code code = TREE_CODE (arg);
2079 if (code == ERROR_MARK)
2082 /* If this is a comparison, we can simply invert it, except for
2083 floating-point non-equality comparisons, in which case we just
2084 enclose a TRUTH_NOT_EXPR around what we have. */
2086 if (TREE_CODE_CLASS (code) == '<')
2088 if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
2089 && code != NE_EXPR && code != EQ_EXPR)
2090 return build1 (TRUTH_NOT_EXPR, type, arg);
2092 return build (invert_tree_comparison (code), type,
2093 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2099 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2100 && TREE_INT_CST_HIGH (arg) == 0, 0));
2102 case TRUTH_AND_EXPR:
2103 return build (TRUTH_OR_EXPR, type,
2104 invert_truthvalue (TREE_OPERAND (arg, 0)),
2105 invert_truthvalue (TREE_OPERAND (arg, 1)));
2108 return build (TRUTH_AND_EXPR, type,
2109 invert_truthvalue (TREE_OPERAND (arg, 0)),
2110 invert_truthvalue (TREE_OPERAND (arg, 1)));
2112 case TRUTH_XOR_EXPR:
2113 /* Here we can invert either operand. We invert the first operand
2114 unless the second operand is a TRUTH_NOT_EXPR in which case our
2115 result is the XOR of the first operand with the inside of the
2116 negation of the second operand. */
2118 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2119 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2120 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2122 return build (TRUTH_XOR_EXPR, type,
2123 invert_truthvalue (TREE_OPERAND (arg, 0)),
2124 TREE_OPERAND (arg, 1));
2126 case TRUTH_ANDIF_EXPR:
2127 return build (TRUTH_ORIF_EXPR, type,
2128 invert_truthvalue (TREE_OPERAND (arg, 0)),
2129 invert_truthvalue (TREE_OPERAND (arg, 1)));
2131 case TRUTH_ORIF_EXPR:
2132 return build (TRUTH_ANDIF_EXPR, type,
2133 invert_truthvalue (TREE_OPERAND (arg, 0)),
2134 invert_truthvalue (TREE_OPERAND (arg, 1)));
2136 case TRUTH_NOT_EXPR:
2137 return TREE_OPERAND (arg, 0);
2140 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2141 invert_truthvalue (TREE_OPERAND (arg, 1)),
2142 invert_truthvalue (TREE_OPERAND (arg, 2)));
2145 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2146 invert_truthvalue (TREE_OPERAND (arg, 1)));
2148 case NON_LVALUE_EXPR:
2149 return invert_truthvalue (TREE_OPERAND (arg, 0));
2154 return build1 (TREE_CODE (arg), type,
2155 invert_truthvalue (TREE_OPERAND (arg, 0)));
2158 if (! integer_onep (TREE_OPERAND (arg, 1)))
2160 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2166 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2167 operands are another bit-wise operation with a common input. If so,
2168 distribute the bit operations to save an operation and possibly two if
2169 constants are involved. For example, convert
2170 (A | B) & (A | C) into A | (B & C)
2171 Further simplification will occur if B and C are constants.
2173 If this optimization cannot be done, 0 will be returned. */
2176 distribute_bit_expr (code, type, arg0, arg1)
2177 enum tree_code code;
2184 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2185 || TREE_CODE (arg0) == code
2186 || (TREE_CODE (arg0) != BIT_AND_EXPR
2187 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2190 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2192 common = TREE_OPERAND (arg0, 0);
2193 left = TREE_OPERAND (arg0, 1);
2194 right = TREE_OPERAND (arg1, 1);
2196 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2198 common = TREE_OPERAND (arg0, 0);
2199 left = TREE_OPERAND (arg0, 1);
2200 right = TREE_OPERAND (arg1, 0);
2202 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2204 common = TREE_OPERAND (arg0, 1);
2205 left = TREE_OPERAND (arg0, 0);
2206 right = TREE_OPERAND (arg1, 1);
2208 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2210 common = TREE_OPERAND (arg0, 1);
2211 left = TREE_OPERAND (arg0, 0);
2212 right = TREE_OPERAND (arg1, 0);
2217 return fold (build (TREE_CODE (arg0), type, common,
2218 fold (build (code, type, left, right))));
2221 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2222 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2225 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2228 int bitsize, bitpos;
2231 tree result = build (BIT_FIELD_REF, type, inner,
2232 size_int (bitsize), size_int (bitpos));
2234 TREE_UNSIGNED (result) = unsignedp;
2239 /* Optimize a bit-field compare.
2241 There are two cases: First is a compare against a constant and the
2242 second is a comparison of two items where the fields are at the same
2243 bit position relative to the start of a chunk (byte, halfword, word)
2244 large enough to contain it. In these cases we can avoid the shift
2245 implicit in bitfield extractions.
2247 For constants, we emit a compare of the shifted constant with the
2248 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2249 compared. For two fields at the same position, we do the ANDs with the
2250 similar mask and compare the result of the ANDs.
2252 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2253 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2254 are the left and right operands of the comparison, respectively.
2256 If the optimization described above can be done, we return the resulting
2257 tree. Otherwise we return zero. */
2260 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2261 enum tree_code code;
2265 int lbitpos, lbitsize, rbitpos, rbitsize;
2266 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2267 tree type = TREE_TYPE (lhs);
2268 tree signed_type, unsigned_type;
2269 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2270 enum machine_mode lmode, rmode, lnmode, rnmode;
2271 int lunsignedp, runsignedp;
2272 int lvolatilep = 0, rvolatilep = 0;
2273 tree linner, rinner;
2277 /* Get all the information about the extractions being done. If the bit size
2278 if the same as the size of the underlying object, we aren't doing an
2279 extraction at all and so can do nothing. */
2280 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2281 &lunsignedp, &lvolatilep);
2282 if (lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2288 /* If this is not a constant, we can only do something if bit positions,
2289 sizes, and signedness are the same. */
2290 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset,
2291 &rmode, &runsignedp, &rvolatilep);
2293 if (lbitpos != rbitpos || lbitsize != rbitsize
2294 || lunsignedp != runsignedp || offset != 0)
2298 /* See if we can find a mode to refer to this field. We should be able to,
2299 but fail if we can't. */
2300 lnmode = get_best_mode (lbitsize, lbitpos,
2301 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2303 if (lnmode == VOIDmode)
2306 /* Set signed and unsigned types of the precision of this mode for the
2308 signed_type = type_for_mode (lnmode, 0);
2309 unsigned_type = type_for_mode (lnmode, 1);
2313 rnmode = get_best_mode (rbitsize, rbitpos,
2314 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2316 if (rnmode == VOIDmode)
2320 /* Compute the bit position and size for the new reference and our offset
2321 within it. If the new reference is the same size as the original, we
2322 won't optimize anything, so return zero. */
2323 lnbitsize = GET_MODE_BITSIZE (lnmode);
2324 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2325 lbitpos -= lnbitpos;
2326 if (lnbitsize == lbitsize)
2331 rnbitsize = GET_MODE_BITSIZE (rnmode);
2332 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2333 rbitpos -= rnbitpos;
2334 if (rnbitsize == rbitsize)
2338 #if BYTES_BIG_ENDIAN
2339 lbitpos = lnbitsize - lbitsize - lbitpos;
2342 /* Make the mask to be used against the extracted field. */
2343 mask = build_int_2 (~0, ~0);
2344 TREE_TYPE (mask) = unsigned_type;
2345 force_fit_type (mask, 0);
2346 mask = convert (unsigned_type, mask);
2347 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2348 mask = const_binop (RSHIFT_EXPR, mask,
2349 size_int (lnbitsize - lbitsize - lbitpos), 0);
2352 /* If not comparing with constant, just rework the comparison
2354 return build (code, compare_type,
2355 build (BIT_AND_EXPR, unsigned_type,
2356 make_bit_field_ref (linner, unsigned_type,
2357 lnbitsize, lnbitpos, 1),
2359 build (BIT_AND_EXPR, unsigned_type,
2360 make_bit_field_ref (rinner, unsigned_type,
2361 rnbitsize, rnbitpos, 1),
2364 /* Otherwise, we are handling the constant case. See if the constant is too
2365 big for the field. Warn and return a tree of for 0 (false) if so. We do
2366 this not only for its own sake, but to avoid having to test for this
2367 error case below. If we didn't, we might generate wrong code.
2369 For unsigned fields, the constant shifted right by the field length should
2370 be all zero. For signed fields, the high-order bits should agree with
2375 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2376 convert (unsigned_type, rhs),
2377 size_int (lbitsize), 0)))
2379 warning ("comparison is always %s due to width of bitfield",
2380 code == NE_EXPR ? "one" : "zero");
2381 return convert (compare_type,
2383 ? integer_one_node : integer_zero_node));
2388 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2389 size_int (lbitsize - 1), 0);
2390 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2392 warning ("comparison is always %s due to width of bitfield",
2393 code == NE_EXPR ? "one" : "zero");
2394 return convert (compare_type,
2396 ? integer_one_node : integer_zero_node));
2400 /* Single-bit compares should always be against zero. */
2401 if (lbitsize == 1 && ! integer_zerop (rhs))
2403 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2404 rhs = convert (type, integer_zero_node);
2407 /* Make a new bitfield reference, shift the constant over the
2408 appropriate number of bits and mask it with the computed mask
2409 (in case this was a signed field). If we changed it, make a new one. */
2410 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2412 rhs = fold (const_binop (BIT_AND_EXPR,
2413 const_binop (LSHIFT_EXPR,
2414 convert (unsigned_type, rhs),
2415 size_int (lbitpos), 0),
2418 return build (code, compare_type,
2419 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2423 /* Subroutine for fold_truthop: decode a field reference.
2425 If EXP is a comparison reference, we return the innermost reference.
2427 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2428 set to the starting bit number.
2430 If the innermost field can be completely contained in a mode-sized
2431 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2433 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2434 otherwise it is not changed.
2436 *PUNSIGNEDP is set to the signedness of the field.
2438 *PMASK is set to the mask used. This is either contained in a
2439 BIT_AND_EXPR or derived from the width of the field.
2441 Return 0 if this is not a component reference or is one that we can't
2442 do anything with. */
2445 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2448 int *pbitsize, *pbitpos;
2449 enum machine_mode *pmode;
2450 int *punsignedp, *pvolatilep;
2457 /* All the optimizations using this function assume integer fields.
2458 There are problems with FP fields since the type_for_size call
2459 below can fail for, e.g., XFmode. */
2460 if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
2465 if (TREE_CODE (exp) == BIT_AND_EXPR)
2467 mask = TREE_OPERAND (exp, 1);
2468 exp = TREE_OPERAND (exp, 0);
2469 STRIP_NOPS (exp); STRIP_NOPS (mask);
2470 if (TREE_CODE (mask) != INTEGER_CST)
2474 if (TREE_CODE (exp) != COMPONENT_REF && TREE_CODE (exp) != ARRAY_REF
2475 && TREE_CODE (exp) != BIT_FIELD_REF)
2478 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2479 punsignedp, pvolatilep);
2480 if (*pbitsize < 0 || offset != 0)
2485 tree unsigned_type = type_for_size (*pbitsize, 1);
2486 int precision = TYPE_PRECISION (unsigned_type);
2488 mask = build_int_2 (~0, ~0);
2489 TREE_TYPE (mask) = unsigned_type;
2490 force_fit_type (mask, 0);
2491 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2492 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2499 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2503 all_ones_mask_p (mask, size)
2507 tree type = TREE_TYPE (mask);
2508 int precision = TYPE_PRECISION (type);
2511 tmask = build_int_2 (~0, ~0);
2512 TREE_TYPE (tmask) = signed_type (type);
2513 force_fit_type (tmask, 0);
2515 operand_equal_p (mask,
2516 const_binop (RSHIFT_EXPR,
2517 const_binop (LSHIFT_EXPR, tmask,
2518 size_int (precision - size), 0),
2519 size_int (precision - size), 0),
2523 /* Subroutine for fold_truthop: determine if an operand is simple enough
2524 to be evaluated unconditionally. */
2527 simple_operand_p (exp)
2530 /* Strip any conversions that don't change the machine mode. */
2531 while ((TREE_CODE (exp) == NOP_EXPR
2532 || TREE_CODE (exp) == CONVERT_EXPR)
2533 && (TYPE_MODE (TREE_TYPE (exp))
2534 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2535 exp = TREE_OPERAND (exp, 0);
2537 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2538 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2539 && ! TREE_ADDRESSABLE (exp)
2540 && ! TREE_THIS_VOLATILE (exp)
2541 && ! DECL_NONLOCAL (exp)
2542 /* Don't regard global variables as simple. They may be
2543 allocated in ways unknown to the compiler (shared memory,
2544 #pragma weak, etc). */
2545 && ! TREE_PUBLIC (exp)
2546 && ! DECL_EXTERNAL (exp)
2547 /* Loading a static variable is unduly expensive, but global
2548 registers aren't expensive. */
2549 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2552 /* Subroutine for fold_truthop: try to optimize a range test.
2554 For example, "i >= 2 && i =< 9" can be done as "(unsigned) (i - 2) <= 7".
2556 JCODE is the logical combination of the two terms. It is TRUTH_AND_EXPR
2557 (representing TRUTH_ANDIF_EXPR and TRUTH_AND_EXPR) or TRUTH_OR_EXPR
2558 (representing TRUTH_ORIF_EXPR and TRUTH_OR_EXPR). TYPE is the type of
2561 VAR is the value being tested. LO_CODE and HI_CODE are the comparison
2562 operators comparing VAR to LO_CST and HI_CST. LO_CST is known to be no
2563 larger than HI_CST (they may be equal).
2565 We return the simplified tree or 0 if no optimization is possible. */
2568 range_test (jcode, type, lo_code, hi_code, var, lo_cst, hi_cst)
2569 enum tree_code jcode, lo_code, hi_code;
2570 tree type, var, lo_cst, hi_cst;
2573 enum tree_code rcode;
2575 /* See if this is a range test and normalize the constant terms. */
2577 if (jcode == TRUTH_AND_EXPR)
2582 /* See if we have VAR != CST && VAR != CST+1. */
2583 if (! (hi_code == NE_EXPR
2584 && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
2585 && tree_int_cst_equal (integer_one_node,
2586 const_binop (MINUS_EXPR,
2587 hi_cst, lo_cst, 0))))
2595 if (hi_code == LT_EXPR)
2596 hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
2597 else if (hi_code != LE_EXPR)
2600 if (lo_code == GT_EXPR)
2601 lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
2603 /* We now have VAR >= LO_CST && VAR <= HI_CST. */
2616 /* See if we have VAR == CST || VAR == CST+1. */
2617 if (! (hi_code == EQ_EXPR
2618 && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
2619 && tree_int_cst_equal (integer_one_node,
2620 const_binop (MINUS_EXPR,
2621 hi_cst, lo_cst, 0))))
2629 if (hi_code == GE_EXPR)
2630 hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
2631 else if (hi_code != GT_EXPR)
2634 if (lo_code == LE_EXPR)
2635 lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
2637 /* We now have VAR < LO_CST || VAR > HI_CST. */
2646 /* When normalizing, it is possible to both increment the smaller constant
2647 and decrement the larger constant. See if they are still ordered. */
2648 if (tree_int_cst_lt (hi_cst, lo_cst))
2651 /* Fail if VAR isn't an integer. */
2652 utype = TREE_TYPE (var);
2653 if (! INTEGRAL_TYPE_P (utype))
2656 /* The range test is invalid if subtracting the two constants results
2657 in overflow. This can happen in traditional mode. */
2658 if (! int_fits_type_p (hi_cst, TREE_TYPE (var))
2659 || ! int_fits_type_p (lo_cst, TREE_TYPE (var)))
2662 if (! TREE_UNSIGNED (utype))
2664 utype = unsigned_type (utype);
2665 var = convert (utype, var);
2666 lo_cst = convert (utype, lo_cst);
2667 hi_cst = convert (utype, hi_cst);
2670 return fold (convert (type,
2671 build (rcode, utype,
2672 build (MINUS_EXPR, utype, var, lo_cst),
2673 const_binop (MINUS_EXPR, hi_cst, lo_cst, 0))));
2676 /* Find ways of folding logical expressions of LHS and RHS:
2677 Try to merge two comparisons to the same innermost item.
2678 Look for range tests like "ch >= '0' && ch <= '9'".
2679 Look for combinations of simple terms on machines with expensive branches
2680 and evaluate the RHS unconditionally.
2682 For example, if we have p->a == 2 && p->b == 4 and we can make an
2683 object large enough to span both A and B, we can do this with a comparison
2684 against the object ANDed with the a mask.
2686 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
2687 operations to do this with one comparison.
2689 We check for both normal comparisons and the BIT_AND_EXPRs made this by
2690 function and the one above.
2692 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
2693 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
2695 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
2698 We return the simplified tree or 0 if no optimization is possible. */
2701 fold_truthop (code, truth_type, lhs, rhs)
2702 enum tree_code code;
2703 tree truth_type, lhs, rhs;
2705 /* If this is the "or" of two comparisons, we can do something if we
2706 the comparisons are NE_EXPR. If this is the "and", we can do something
2707 if the comparisons are EQ_EXPR. I.e.,
2708 (a->b == 2 && a->c == 4) can become (a->new == NEW).
2710 WANTED_CODE is this operation code. For single bit fields, we can
2711 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
2712 comparison for one-bit fields. */
2714 enum tree_code wanted_code;
2715 enum tree_code lcode, rcode;
2716 tree ll_arg, lr_arg, rl_arg, rr_arg;
2717 tree ll_inner, lr_inner, rl_inner, rr_inner;
2718 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
2719 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
2720 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
2721 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
2722 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
2723 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
2724 enum machine_mode lnmode, rnmode;
2725 tree ll_mask, lr_mask, rl_mask, rr_mask;
2726 tree l_const, r_const;
2728 int first_bit, end_bit;
2731 /* Start by getting the comparison codes and seeing if this looks like
2732 a range test. Fail if anything is volatile. If one operand is a
2733 BIT_AND_EXPR with the constant one, treat it as if it were surrounded
2736 if (TREE_SIDE_EFFECTS (lhs)
2737 || TREE_SIDE_EFFECTS (rhs))
2740 lcode = TREE_CODE (lhs);
2741 rcode = TREE_CODE (rhs);
2743 if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
2744 lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
2746 if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
2747 rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
2749 if (TREE_CODE_CLASS (lcode) != '<'
2750 || TREE_CODE_CLASS (rcode) != '<')
2753 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
2754 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
2756 ll_arg = TREE_OPERAND (lhs, 0);
2757 lr_arg = TREE_OPERAND (lhs, 1);
2758 rl_arg = TREE_OPERAND (rhs, 0);
2759 rr_arg = TREE_OPERAND (rhs, 1);
2761 if (TREE_CODE (lr_arg) == INTEGER_CST
2762 && TREE_CODE (rr_arg) == INTEGER_CST
2763 && operand_equal_p (ll_arg, rl_arg, 0))
2765 if (tree_int_cst_lt (lr_arg, rr_arg))
2766 result = range_test (code, truth_type, lcode, rcode,
2767 ll_arg, lr_arg, rr_arg);
2769 result = range_test (code, truth_type, rcode, lcode,
2770 ll_arg, rr_arg, lr_arg);
2772 /* If this isn't a range test, it also isn't a comparison that
2773 can be merged. However, it wins to evaluate the RHS unconditionally
2774 on machines with expensive branches. */
2776 if (result == 0 && BRANCH_COST >= 2)
2778 if (TREE_CODE (ll_arg) != VAR_DECL
2779 && TREE_CODE (ll_arg) != PARM_DECL)
2781 /* Avoid evaluating the variable part twice. */
2782 ll_arg = save_expr (ll_arg);
2783 lhs = build (lcode, TREE_TYPE (lhs), ll_arg, lr_arg);
2784 rhs = build (rcode, TREE_TYPE (rhs), ll_arg, rr_arg);
2786 return build (code, truth_type, lhs, rhs);
2791 /* If the RHS can be evaluated unconditionally and its operands are
2792 simple, it wins to evaluate the RHS unconditionally on machines
2793 with expensive branches. In this case, this isn't a comparison
2794 that can be merged. */
2796 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
2797 are with zero (tmw). */
2799 if (BRANCH_COST >= 2
2800 && INTEGRAL_TYPE_P (TREE_TYPE (rhs))
2801 && simple_operand_p (rl_arg)
2802 && simple_operand_p (rr_arg))
2803 return build (code, truth_type, lhs, rhs);
2805 /* See if the comparisons can be merged. Then get all the parameters for
2808 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
2809 || (rcode != EQ_EXPR && rcode != NE_EXPR))
2813 ll_inner = decode_field_reference (ll_arg,
2814 &ll_bitsize, &ll_bitpos, &ll_mode,
2815 &ll_unsignedp, &volatilep, &ll_mask);
2816 lr_inner = decode_field_reference (lr_arg,
2817 &lr_bitsize, &lr_bitpos, &lr_mode,
2818 &lr_unsignedp, &volatilep, &lr_mask);
2819 rl_inner = decode_field_reference (rl_arg,
2820 &rl_bitsize, &rl_bitpos, &rl_mode,
2821 &rl_unsignedp, &volatilep, &rl_mask);
2822 rr_inner = decode_field_reference (rr_arg,
2823 &rr_bitsize, &rr_bitpos, &rr_mode,
2824 &rr_unsignedp, &volatilep, &rr_mask);
2826 /* It must be true that the inner operation on the lhs of each
2827 comparison must be the same if we are to be able to do anything.
2828 Then see if we have constants. If not, the same must be true for
2830 if (volatilep || ll_inner == 0 || rl_inner == 0
2831 || ! operand_equal_p (ll_inner, rl_inner, 0))
2834 if (TREE_CODE (lr_arg) == INTEGER_CST
2835 && TREE_CODE (rr_arg) == INTEGER_CST)
2836 l_const = lr_arg, r_const = rr_arg;
2837 else if (lr_inner == 0 || rr_inner == 0
2838 || ! operand_equal_p (lr_inner, rr_inner, 0))
2841 l_const = r_const = 0;
2843 /* If either comparison code is not correct for our logical operation,
2844 fail. However, we can convert a one-bit comparison against zero into
2845 the opposite comparison against that bit being set in the field. */
2847 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
2848 if (lcode != wanted_code)
2850 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
2856 if (rcode != wanted_code)
2858 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
2864 /* See if we can find a mode that contains both fields being compared on
2865 the left. If we can't, fail. Otherwise, update all constants and masks
2866 to be relative to a field of that size. */
2867 first_bit = MIN (ll_bitpos, rl_bitpos);
2868 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
2869 lnmode = get_best_mode (end_bit - first_bit, first_bit,
2870 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
2872 if (lnmode == VOIDmode)
2875 lnbitsize = GET_MODE_BITSIZE (lnmode);
2876 lnbitpos = first_bit & ~ (lnbitsize - 1);
2877 type = type_for_size (lnbitsize, 1);
2878 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
2880 #if BYTES_BIG_ENDIAN
2881 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
2882 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
2885 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
2886 size_int (xll_bitpos), 0);
2887 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
2888 size_int (xrl_bitpos), 0);
2890 /* Make sure the constants are interpreted as unsigned, so we
2891 don't have sign bits outside the range of their type. */
2895 l_const = convert (unsigned_type (TREE_TYPE (l_const)), l_const);
2896 l_const = const_binop (LSHIFT_EXPR, convert (type, l_const),
2897 size_int (xll_bitpos), 0);
2901 r_const = convert (unsigned_type (TREE_TYPE (r_const)), r_const);
2902 r_const = const_binop (LSHIFT_EXPR, convert (type, r_const),
2903 size_int (xrl_bitpos), 0);
2906 /* If the right sides are not constant, do the same for it. Also,
2907 disallow this optimization if a size or signedness mismatch occurs
2908 between the left and right sides. */
2911 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
2912 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
2913 /* Make sure the two fields on the right
2914 correspond to the left without being swapped. */
2915 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
2918 first_bit = MIN (lr_bitpos, rr_bitpos);
2919 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
2920 rnmode = get_best_mode (end_bit - first_bit, first_bit,
2921 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
2923 if (rnmode == VOIDmode)
2926 rnbitsize = GET_MODE_BITSIZE (rnmode);
2927 rnbitpos = first_bit & ~ (rnbitsize - 1);
2928 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
2930 #if BYTES_BIG_ENDIAN
2931 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
2932 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
2935 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
2936 size_int (xlr_bitpos), 0);
2937 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
2938 size_int (xrr_bitpos), 0);
2940 /* Make a mask that corresponds to both fields being compared.
2941 Do this for both items being compared. If the masks agree,
2942 we can do this by masking both and comparing the masked
2944 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
2945 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
2946 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
2948 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
2949 ll_unsignedp || rl_unsignedp);
2950 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
2951 lr_unsignedp || rr_unsignedp);
2952 if (! all_ones_mask_p (ll_mask, lnbitsize))
2954 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
2955 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
2957 return build (wanted_code, truth_type, lhs, rhs);
2960 /* There is still another way we can do something: If both pairs of
2961 fields being compared are adjacent, we may be able to make a wider
2962 field containing them both. */
2963 if ((ll_bitsize + ll_bitpos == rl_bitpos
2964 && lr_bitsize + lr_bitpos == rr_bitpos)
2965 || (ll_bitpos == rl_bitpos + rl_bitsize
2966 && lr_bitpos == rr_bitpos + rr_bitsize))
2967 return build (wanted_code, truth_type,
2968 make_bit_field_ref (ll_inner, type,
2969 ll_bitsize + rl_bitsize,
2970 MIN (ll_bitpos, rl_bitpos),
2972 make_bit_field_ref (lr_inner, type,
2973 lr_bitsize + rr_bitsize,
2974 MIN (lr_bitpos, rr_bitpos),
2980 /* Handle the case of comparisons with constants. If there is something in
2981 common between the masks, those bits of the constants must be the same.
2982 If not, the condition is always false. Test for this to avoid generating
2983 incorrect code below. */
2984 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
2985 if (! integer_zerop (result)
2986 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
2987 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
2989 if (wanted_code == NE_EXPR)
2991 warning ("`or' of unmatched not-equal tests is always 1");
2992 return convert (truth_type, integer_one_node);
2996 warning ("`and' of mutually exclusive equal-tests is always zero");
2997 return convert (truth_type, integer_zero_node);
3001 /* Construct the expression we will return. First get the component
3002 reference we will make. Unless the mask is all ones the width of
3003 that field, perform the mask operation. Then compare with the
3005 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
3006 ll_unsignedp || rl_unsignedp);
3008 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
3009 if (! all_ones_mask_p (ll_mask, lnbitsize))
3010 result = build (BIT_AND_EXPR, type, result, ll_mask);
3012 return build (wanted_code, truth_type, result,
3013 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
3016 /* Perform constant folding and related simplification of EXPR.
3017 The related simplifications include x*1 => x, x*0 => 0, etc.,
3018 and application of the associative law.
3019 NOP_EXPR conversions may be removed freely (as long as we
3020 are careful not to change the C type of the overall expression)
3021 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
3022 but we can constant-fold them if they have constant operands. */
3028 register tree t = expr;
3029 tree t1 = NULL_TREE;
3031 tree type = TREE_TYPE (expr);
3032 register tree arg0, arg1;
3033 register enum tree_code code = TREE_CODE (t);
3037 /* WINS will be nonzero when the switch is done
3038 if all operands are constant. */
3042 /* Return right away if already constant. */
3043 if (TREE_CONSTANT (t))
3045 if (code == CONST_DECL)
3046 return DECL_INITIAL (t);
3050 kind = TREE_CODE_CLASS (code);
3051 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3055 /* Special case for conversion ops that can have fixed point args. */
3056 arg0 = TREE_OPERAND (t, 0);
3058 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3060 STRIP_TYPE_NOPS (arg0);
3062 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3063 subop = TREE_REALPART (arg0);
3067 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3068 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3069 && TREE_CODE (subop) != REAL_CST
3070 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3072 /* Note that TREE_CONSTANT isn't enough:
3073 static var addresses are constant but we can't
3074 do arithmetic on them. */
3077 else if (kind == 'e' || kind == '<'
3078 || kind == '1' || kind == '2' || kind == 'r')
3080 register int len = tree_code_length[(int) code];
3082 for (i = 0; i < len; i++)
3084 tree op = TREE_OPERAND (t, i);
3088 continue; /* Valid for CALL_EXPR, at least. */
3090 if (kind == '<' || code == RSHIFT_EXPR)
3092 /* Signedness matters here. Perhaps we can refine this
3094 STRIP_TYPE_NOPS (op);
3098 /* Strip any conversions that don't change the mode. */
3102 if (TREE_CODE (op) == COMPLEX_CST)
3103 subop = TREE_REALPART (op);
3107 if (TREE_CODE (subop) != INTEGER_CST
3108 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3109 && TREE_CODE (subop) != REAL_CST
3110 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3112 /* Note that TREE_CONSTANT isn't enough:
3113 static var addresses are constant but we can't
3114 do arithmetic on them. */
3124 /* If this is a commutative operation, and ARG0 is a constant, move it
3125 to ARG1 to reduce the number of tests below. */
3126 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3127 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3128 || code == BIT_AND_EXPR)
3129 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3131 tem = arg0; arg0 = arg1; arg1 = tem;
3133 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3134 TREE_OPERAND (t, 1) = tem;
3137 /* Now WINS is set as described above,
3138 ARG0 is the first operand of EXPR,
3139 and ARG1 is the second operand (if it has more than one operand).
3141 First check for cases where an arithmetic operation is applied to a
3142 compound, conditional, or comparison operation. Push the arithmetic
3143 operation inside the compound or conditional to see if any folding
3144 can then be done. Convert comparison to conditional for this purpose.
3145 The also optimizes non-constant cases that used to be done in
3148 Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR,
3149 one of the operands is a comparison and the other is either a comparison
3150 or a BIT_AND_EXPR with the constant 1. In that case, the code below
3151 would make the expression more complex. Change it to a
3152 TRUTH_{AND,OR}_EXPR. */
3154 if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
3155 && ((TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3156 && (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3157 || (TREE_CODE (arg1) == BIT_AND_EXPR
3158 && integer_onep (TREE_OPERAND (arg1, 1)))))
3159 || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
3160 && (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
3161 || (TREE_CODE (arg0) == BIT_AND_EXPR
3162 && integer_onep (TREE_OPERAND (arg0, 1)))))))
3163 return fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
3166 if (TREE_CODE_CLASS (code) == '1')
3168 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3169 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3170 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3171 else if (TREE_CODE (arg0) == COND_EXPR)
3173 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3174 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3175 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3177 /* If this was a conversion, and all we did was to move into
3178 inside the COND_EXPR, bring it back out. Then return so we
3179 don't get into an infinite recursion loop taking the conversion
3180 out and then back in. */
3182 if ((code == NOP_EXPR || code == CONVERT_EXPR
3183 || code == NON_LVALUE_EXPR)
3184 && TREE_CODE (t) == COND_EXPR
3185 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3186 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3187 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3188 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0))))
3189 t = build1 (code, type,
3191 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3192 TREE_OPERAND (t, 0),
3193 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3194 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3197 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3198 return fold (build (COND_EXPR, type, arg0,
3199 fold (build1 (code, type, integer_one_node)),
3200 fold (build1 (code, type, integer_zero_node))));
3202 else if (TREE_CODE_CLASS (code) == '2'
3203 || TREE_CODE_CLASS (code) == '<')
3205 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3206 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3207 fold (build (code, type,
3208 arg0, TREE_OPERAND (arg1, 1))));
3209 else if (TREE_CODE (arg1) == COND_EXPR
3210 || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<')
3212 tree test, true_value, false_value;
3214 if (TREE_CODE (arg1) == COND_EXPR)
3216 test = TREE_OPERAND (arg1, 0);
3217 true_value = TREE_OPERAND (arg1, 1);
3218 false_value = TREE_OPERAND (arg1, 2);
3223 true_value = integer_one_node;
3224 false_value = integer_zero_node;
3227 /* If ARG0 is complex we want to make sure we only evaluate
3228 it once. Though this is only required if it is volatile, it
3229 might be more efficient even if it is not. However, if we
3230 succeed in folding one part to a constant, we do not need
3231 to make this SAVE_EXPR. Since we do this optimization
3232 primarily to see if we do end up with constant and this
3233 SAVE_EXPR interfers with later optimizations, suppressing
3234 it when we can is important. */
3236 if ((TREE_CODE (arg0) != VAR_DECL && TREE_CODE (arg0) != PARM_DECL)
3237 || TREE_SIDE_EFFECTS (arg0))
3239 tree lhs = fold (build (code, type, arg0, true_value));
3240 tree rhs = fold (build (code, type, arg0, false_value));
3242 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3243 return fold (build (COND_EXPR, type, test, lhs, rhs));
3245 arg0 = save_expr (arg0);
3248 test = fold (build (COND_EXPR, type, test,
3249 fold (build (code, type, arg0, true_value)),
3250 fold (build (code, type, arg0, false_value))));
3251 if (TREE_CODE (arg0) == SAVE_EXPR)
3252 return build (COMPOUND_EXPR, type,
3253 convert (void_type_node, arg0), test);
3255 return convert (type, test);
3258 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3259 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3260 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3261 else if (TREE_CODE (arg0) == COND_EXPR
3262 || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3264 tree test, true_value, false_value;
3266 if (TREE_CODE (arg0) == COND_EXPR)
3268 test = TREE_OPERAND (arg0, 0);
3269 true_value = TREE_OPERAND (arg0, 1);
3270 false_value = TREE_OPERAND (arg0, 2);
3275 true_value = integer_one_node;
3276 false_value = integer_zero_node;
3279 if ((TREE_CODE (arg1) != VAR_DECL && TREE_CODE (arg1) != PARM_DECL)
3280 || TREE_SIDE_EFFECTS (arg1))
3282 tree lhs = fold (build (code, type, true_value, arg1));
3283 tree rhs = fold (build (code, type, false_value, arg1));
3285 if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs))
3286 return fold (build (COND_EXPR, type, test, lhs, rhs));
3288 arg1 = save_expr (arg1);
3291 test = fold (build (COND_EXPR, type, test,
3292 fold (build (code, type, true_value, arg1)),
3293 fold (build (code, type, false_value, arg1))));
3294 if (TREE_CODE (arg1) == SAVE_EXPR)
3295 return build (COMPOUND_EXPR, type,
3296 convert (void_type_node, arg1), test);
3298 return convert (type, test);
3301 else if (TREE_CODE_CLASS (code) == '<'
3302 && TREE_CODE (arg0) == COMPOUND_EXPR)
3303 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3304 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3305 else if (TREE_CODE_CLASS (code) == '<'
3306 && TREE_CODE (arg1) == COMPOUND_EXPR)
3307 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3308 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3320 return fold (DECL_INITIAL (t));
3325 case FIX_TRUNC_EXPR:
3326 /* Other kinds of FIX are not handled properly by fold_convert. */
3327 /* Two conversions in a row are not needed unless:
3328 - the intermediate type is narrower than both initial and final, or
3329 - the intermediate type and innermost type differ in signedness,
3330 and the outermost type is wider than the intermediate, or
3331 - the initial type is a pointer type and the precisions of the
3332 intermediate and final types differ, or
3333 - the final type is a pointer type and the precisions of the
3334 initial and intermediate types differ. */
3335 if ((TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
3336 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
3337 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3338 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3340 TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3341 > TYPE_PRECISION (TREE_TYPE (t)))
3342 && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3344 && (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
3346 && (TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0)))
3347 != TREE_UNSIGNED (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3348 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3349 < TYPE_PRECISION (TREE_TYPE (t))))
3350 && ((TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0)))
3351 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3352 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))))
3354 (TREE_UNSIGNED (TREE_TYPE (t))
3355 && (TYPE_PRECISION (TREE_TYPE (t))
3356 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))))))
3357 && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3359 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3360 != TYPE_PRECISION (TREE_TYPE (t))))
3361 && ! (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE
3362 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3363 != TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))))))
3364 return convert (TREE_TYPE (t), TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3366 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
3367 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
3368 /* Detect assigning a bitfield. */
3369 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
3370 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
3372 /* Don't leave an assignment inside a conversion
3373 unless assigning a bitfield. */
3374 tree prev = TREE_OPERAND (t, 0);
3375 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
3376 /* First do the assignment, then return converted constant. */
3377 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
3383 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
3386 return fold_convert (t, arg0);
3388 #if 0 /* This loses on &"foo"[0]. */
3393 /* Fold an expression like: "foo"[2] */
3394 if (TREE_CODE (arg0) == STRING_CST
3395 && TREE_CODE (arg1) == INTEGER_CST
3396 && !TREE_INT_CST_HIGH (arg1)
3397 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
3399 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
3400 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
3401 force_fit_type (t, 0);
3408 TREE_CONSTANT (t) = wins;
3414 if (TREE_CODE (arg0) == INTEGER_CST)
3416 HOST_WIDE_INT low, high;
3417 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
3418 TREE_INT_CST_HIGH (arg0),
3420 t = build_int_2 (low, high);
3421 TREE_TYPE (t) = type;
3423 = (TREE_OVERFLOW (arg0)
3424 | force_fit_type (t, overflow));
3425 TREE_CONSTANT_OVERFLOW (t)
3426 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
3428 else if (TREE_CODE (arg0) == REAL_CST)
3429 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
3430 TREE_TYPE (t) = type;
3432 else if (TREE_CODE (arg0) == NEGATE_EXPR)
3433 return TREE_OPERAND (arg0, 0);
3435 /* Convert - (a - b) to (b - a) for non-floating-point. */
3436 else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type))
3437 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
3438 TREE_OPERAND (arg0, 0));
3445 if (TREE_CODE (arg0) == INTEGER_CST)
3447 if (! TREE_UNSIGNED (type)
3448 && TREE_INT_CST_HIGH (arg0) < 0)
3450 HOST_WIDE_INT low, high;
3451 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
3452 TREE_INT_CST_HIGH (arg0),
3454 t = build_int_2 (low, high);
3455 TREE_TYPE (t) = type;
3457 = (TREE_OVERFLOW (arg0)
3458 | force_fit_type (t, overflow));
3459 TREE_CONSTANT_OVERFLOW (t)
3460 = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
3463 else if (TREE_CODE (arg0) == REAL_CST)
3465 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
3466 t = build_real (type,
3467 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
3469 TREE_TYPE (t) = type;
3471 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
3472 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
3478 if (TREE_CODE (arg0) == INTEGER_CST)
3479 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
3480 ~ TREE_INT_CST_HIGH (arg0));
3481 TREE_TYPE (t) = type;
3482 force_fit_type (t, 0);
3483 TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
3484 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
3486 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
3487 return TREE_OPERAND (arg0, 0);
3491 /* A + (-B) -> A - B */
3492 if (TREE_CODE (arg1) == NEGATE_EXPR)
3493 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
3494 else if (! FLOAT_TYPE_P (type))
3496 if (integer_zerop (arg1))
3497 return non_lvalue (convert (type, arg0));
3499 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
3500 with a constant, and the two constants have no bits in common,
3501 we should treat this as a BIT_IOR_EXPR since this may produce more
3503 if (TREE_CODE (arg0) == BIT_AND_EXPR
3504 && TREE_CODE (arg1) == BIT_AND_EXPR
3505 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
3506 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
3507 && integer_zerop (const_binop (BIT_AND_EXPR,
3508 TREE_OPERAND (arg0, 1),
3509 TREE_OPERAND (arg1, 1), 0)))
3511 code = BIT_IOR_EXPR;
3515 /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned
3516 about the case where C is a constant, just try one of the
3517 four possibilities. */
3519 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
3520 && operand_equal_p (TREE_OPERAND (arg0, 1),
3521 TREE_OPERAND (arg1, 1), 0))
3522 return fold (build (MULT_EXPR, type,
3523 fold (build (PLUS_EXPR, type,
3524 TREE_OPERAND (arg0, 0),
3525 TREE_OPERAND (arg1, 0))),
3526 TREE_OPERAND (arg0, 1)));
3528 /* In IEEE floating point, x+0 may not equal x. */
3529 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3530 && real_zerop (arg1))
3531 return non_lvalue (convert (type, arg0));
3533 /* In most languages, can't associate operations on floats
3534 through parentheses. Rather than remember where the parentheses
3535 were, we don't associate floats at all. It shouldn't matter much. */
3536 if (FLOAT_TYPE_P (type))
3538 /* The varsign == -1 cases happen only for addition and subtraction.
3539 It says that the arg that was split was really CON minus VAR.
3540 The rest of the code applies to all associative operations. */
3546 if (split_tree (arg0, code, &var, &con, &varsign))
3550 /* EXPR is (CON-VAR) +- ARG1. */
3551 /* If it is + and VAR==ARG1, return just CONST. */
3552 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
3553 return convert (TREE_TYPE (t), con);
3555 /* If ARG0 is a constant, don't change things around;
3556 instead keep all the constant computations together. */
3558 if (TREE_CONSTANT (arg0))
3561 /* Otherwise return (CON +- ARG1) - VAR. */
3562 TREE_SET_CODE (t, MINUS_EXPR);
3563 TREE_OPERAND (t, 1) = var;
3565 = fold (build (code, TREE_TYPE (t), con, arg1));
3569 /* EXPR is (VAR+CON) +- ARG1. */
3570 /* If it is - and VAR==ARG1, return just CONST. */
3571 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
3572 return convert (TREE_TYPE (t), con);
3574 /* If ARG0 is a constant, don't change things around;
3575 instead keep all the constant computations together. */
3577 if (TREE_CONSTANT (arg0))
3580 /* Otherwise return VAR +- (ARG1 +- CON). */
3581 TREE_OPERAND (t, 1) = tem
3582 = fold (build (code, TREE_TYPE (t), arg1, con));
3583 TREE_OPERAND (t, 0) = var;
3584 if (integer_zerop (tem)
3585 && (code == PLUS_EXPR || code == MINUS_EXPR))
3586 return convert (type, var);
3587 /* If we have x +/- (c - d) [c an explicit integer]
3588 change it to x -/+ (d - c) since if d is relocatable
3589 then the latter can be a single immediate insn
3590 and the former cannot. */
3591 if (TREE_CODE (tem) == MINUS_EXPR
3592 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
3594 tree tem1 = TREE_OPERAND (tem, 1);
3595 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
3596 TREE_OPERAND (tem, 0) = tem1;
3598 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
3604 if (split_tree (arg1, code, &var, &con, &varsign))
3606 /* EXPR is ARG0 +- (CON +- VAR). */
3607 if (TREE_CODE (t) == MINUS_EXPR
3608 && operand_equal_p (var, arg0, 0))
3610 /* If VAR and ARG0 cancel, return just CON or -CON. */
3611 if (code == PLUS_EXPR)
3612 return convert (TREE_TYPE (t), con);
3613 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
3614 convert (TREE_TYPE (t), con)));
3616 if (TREE_CONSTANT (arg1))
3620 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
3622 = fold (build (code, TREE_TYPE (t), arg0, con));
3623 TREE_OPERAND (t, 1) = var;
3624 if (integer_zerop (TREE_OPERAND (t, 0))
3625 && TREE_CODE (t) == PLUS_EXPR)
3626 return convert (TREE_TYPE (t), var);
3631 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
3632 if (TREE_CODE (arg1) == REAL_CST)
3634 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
3636 t1 = const_binop (code, arg0, arg1, 0);
3637 if (t1 != NULL_TREE)
3639 /* The return value should always have
3640 the same type as the original expression. */
3641 TREE_TYPE (t1) = TREE_TYPE (t);
3647 if (! FLOAT_TYPE_P (type))
3649 if (! wins && integer_zerop (arg0))
3650 return build1 (NEGATE_EXPR, type, arg1);
3651 if (integer_zerop (arg1))
3652 return non_lvalue (convert (type, arg0));
3654 /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
3655 about the case where C is a constant, just try one of the
3656 four possibilities. */
3658 if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
3659 && operand_equal_p (TREE_OPERAND (arg0, 1),
3660 TREE_OPERAND (arg1, 1), 0))
3661 return fold (build (MULT_EXPR, type,
3662 fold (build (MINUS_EXPR, type,
3663 TREE_OPERAND (arg0, 0),
3664 TREE_OPERAND (arg1, 0))),
3665 TREE_OPERAND (arg0, 1)));
3667 /* Convert A - (-B) to A + B. */
3668 else if (TREE_CODE (arg1) == NEGATE_EXPR)
3669 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
3670 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
3672 /* Except with IEEE floating point, 0-x equals -x. */
3673 if (! wins && real_zerop (arg0))
3674 return build1 (NEGATE_EXPR, type, arg1);
3675 /* Except with IEEE floating point, x-0 equals x. */
3676 if (real_zerop (arg1))
3677 return non_lvalue (convert (type, arg0));
3679 /* Fold &x - &x. This can happen from &x.foo - &x.
3680 This is unsafe for certain floats even in non-IEEE formats.
3681 In IEEE, it is unsafe because it does wrong for NaNs.
3682 Also note that operand_equal_p is always false if an operand
3685 if (operand_equal_p (arg0, arg1, FLOAT_TYPE_P (type)))
3686 return convert (type, integer_zero_node);
3691 if (! FLOAT_TYPE_P (type))
3693 if (integer_zerop (arg1))
3694 return omit_one_operand (type, arg1, arg0);
3695 if (integer_onep (arg1))
3696 return non_lvalue (convert (type, arg0));
3698 /* (a * (1 << b)) is (a << b) */
3699 if (TREE_CODE (arg1) == LSHIFT_EXPR
3700 && integer_onep (TREE_OPERAND (arg1, 0)))
3701 return fold (build (LSHIFT_EXPR, type, arg0,
3702 TREE_OPERAND (arg1, 1)));
3703 if (TREE_CODE (arg0) == LSHIFT_EXPR
3704 && integer_onep (TREE_OPERAND (arg0, 0)))
3705 return fold (build (LSHIFT_EXPR, type, arg1,
3706 TREE_OPERAND (arg0, 1)));
3710 /* x*0 is 0, except for IEEE floating point. */
3711 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3712 && real_zerop (arg1))
3713 return omit_one_operand (type, arg1, arg0);
3714 /* In IEEE floating point, x*1 is not equivalent to x for snans.
3715 However, ANSI says we can drop signals,
3716 so we can do this anyway. */
3717 if (real_onep (arg1))
3718 return non_lvalue (convert (type, arg0));
3720 if (! wins && real_twop (arg1))
3722 tree arg = save_expr (arg0);
3723 return build (PLUS_EXPR, type, arg, arg);
3730 if (integer_all_onesp (arg1))
3731 return omit_one_operand (type, arg1, arg0);
3732 if (integer_zerop (arg1))
3733 return non_lvalue (convert (type, arg0));
3734 t1 = distribute_bit_expr (code, type, arg0, arg1);
3735 if (t1 != NULL_TREE)
3738 /* (a << C1) | (a >> C2) if A is unsigned and C1+C2 is the size of A
3739 is a rotate of A by C1 bits. */
3741 if ((TREE_CODE (arg0) == RSHIFT_EXPR
3742 || TREE_CODE (arg0) == LSHIFT_EXPR)
3743 && (TREE_CODE (arg1) == RSHIFT_EXPR
3744 || TREE_CODE (arg1) == LSHIFT_EXPR)
3745 && TREE_CODE (arg0) != TREE_CODE (arg1)
3746 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
3747 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))
3748 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
3749 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
3750 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
3751 && TREE_INT_CST_HIGH (TREE_OPERAND (arg1, 1)) == 0
3752 && ((TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))
3753 + TREE_INT_CST_LOW (TREE_OPERAND (arg1, 1)))
3754 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
3755 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
3756 TREE_CODE (arg0) == LSHIFT_EXPR
3757 ? TREE_OPERAND (arg0, 1) : TREE_OPERAND (arg1, 1));
3762 if (integer_zerop (arg1))
3763 return non_lvalue (convert (type, arg0));
3764 if (integer_all_onesp (arg1))
3765 return fold (build1 (BIT_NOT_EXPR, type, arg0));
3770 if (integer_all_onesp (arg1))
3771 return non_lvalue (convert (type, arg0));
3772 if (integer_zerop (arg1))
3773 return omit_one_operand (type, arg1, arg0);
3774 t1 = distribute_bit_expr (code, type, arg0, arg1);
3775 if (t1 != NULL_TREE)
3777 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
3778 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
3779 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
3781 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
3782 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
3783 && (~TREE_INT_CST_LOW (arg0)
3784 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
3785 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
3787 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
3788 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
3790 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
3791 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
3792 && (~TREE_INT_CST_LOW (arg1)
3793 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
3794 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
3798 case BIT_ANDTC_EXPR:
3799 if (integer_all_onesp (arg0))
3800 return non_lvalue (convert (type, arg1));
3801 if (integer_zerop (arg0))
3802 return omit_one_operand (type, arg0, arg1);
3803 if (TREE_CODE (arg1) == INTEGER_CST)
3805 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
3806 code = BIT_AND_EXPR;
3811 case TRUNC_DIV_EXPR:
3812 case ROUND_DIV_EXPR:
3813 case FLOOR_DIV_EXPR:
3815 case EXACT_DIV_EXPR:
3817 if (integer_onep (arg1))
3818 return non_lvalue (convert (type, arg0));
3819 if (integer_zerop (arg1))
3822 /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3),
3823 where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these
3824 expressions, which often appear in the offsets or sizes of
3825 objects with a varying size. Only deal with positive divisors
3828 Look for NOPs and SAVE_EXPRs inside. */
3830 if (TREE_CODE (arg1) == INTEGER_CST
3831 && tree_int_cst_lt (integer_zero_node, arg1))
3833 int have_save_expr = 0;
3834 tree c2 = integer_zero_node;
3837 if (TREE_CODE (xarg0) == SAVE_EXPR)
3838 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
3842 if (TREE_CODE (xarg0) == PLUS_EXPR
3843 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
3844 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
3845 else if (TREE_CODE (xarg0) == MINUS_EXPR
3846 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
3848 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
3849 xarg0 = TREE_OPERAND (xarg0, 0);
3852 if (TREE_CODE (xarg0) == SAVE_EXPR)
3853 have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0);
3857 if (TREE_CODE (xarg0) == MULT_EXPR
3858 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
3859 && tree_int_cst_lt (integer_zero_node, TREE_OPERAND (xarg0, 1))
3860 && (integer_zerop (const_binop (TRUNC_MOD_EXPR,
3861 TREE_OPERAND (xarg0, 1), arg1, 1))
3862 || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1,
3863 TREE_OPERAND (xarg0, 1), 1))))
3865 tree outer_div = integer_one_node;
3866 tree c1 = TREE_OPERAND (xarg0, 1);
3869 /* If C3 > C1, set them equal and do a divide by
3870 C3/C1 at the end of the operation. */
3871 if (tree_int_cst_lt (c1, c3))
3872 outer_div = const_binop (code, c3, c1, 0), c3 = c1;
3874 /* The result is A * (C1/C3) + (C2/C3). */
3875 t = fold (build (PLUS_EXPR, type,
3876 fold (build (MULT_EXPR, type,
3877 TREE_OPERAND (xarg0, 0),
3878 const_binop (code, c1, c3, 1))),
3879 const_binop (code, c2, c3, 1)));
3881 if (! integer_onep (outer_div))
3882 t = fold (build (code, type, t, outer_div));
3891 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3892 #ifndef REAL_INFINITY
3893 if (TREE_CODE (arg1) == REAL_CST
3894 && real_zerop (arg1))
3897 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3902 case FLOOR_MOD_EXPR:
3903 case ROUND_MOD_EXPR:
3904 case TRUNC_MOD_EXPR:
3905 if (integer_onep (arg1))
3906 return omit_one_operand (type, integer_zero_node, arg0);
3907 if (integer_zerop (arg1))
3910 /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3),
3911 where C1 % C3 == 0. Handle similarly to the division case,
3912 but don't bother with SAVE_EXPRs. */
3914 if (TREE_CODE (arg1) == INTEGER_CST
3915 && ! integer_zerop (arg1))
3917 tree c2 = integer_zero_node;
3920 if (TREE_CODE (xarg0) == PLUS_EXPR
3921 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
3922 c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0);
3923 else if (TREE_CODE (xarg0) == MINUS_EXPR
3924 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST)
3926 c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1)));
3927 xarg0 = TREE_OPERAND (xarg0, 0);
3932 if (TREE_CODE (xarg0) == MULT_EXPR
3933 && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST
3934 && integer_zerop (const_binop (TRUNC_MOD_EXPR,
3935 TREE_OPERAND (xarg0, 1),
3937 /* The result is (C2%C3). */
3938 return omit_one_operand (type, const_binop (code, c2, arg1, 1),
3939 TREE_OPERAND (xarg0, 0));
3948 if (integer_zerop (arg1))
3949 return non_lvalue (convert (type, arg0));
3950 /* Since negative shift count is not well-defined,
3951 don't try to compute it in the compiler. */
3952 if (tree_int_cst_lt (arg1, integer_zero_node))
3957 if (operand_equal_p (arg0, arg1, 0))
3959 if (INTEGRAL_TYPE_P (type)
3960 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
3961 return omit_one_operand (type, arg1, arg0);
3965 if (operand_equal_p (arg0, arg1, 0))
3967 if (INTEGRAL_TYPE_P (type)
3968 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
3969 return omit_one_operand (type, arg1, arg0);
3972 case TRUTH_NOT_EXPR:
3973 /* Note that the operand of this must be an int
3974 and its values must be 0 or 1.
3975 ("true" is a fixed value perhaps depending on the language,
3976 but we don't handle values other than 1 correctly yet.) */
3977 return invert_truthvalue (arg0);
3979 case TRUTH_ANDIF_EXPR:
3980 /* Note that the operands of this must be ints
3981 and their values must be 0 or 1.
3982 ("true" is a fixed value perhaps depending on the language.) */
3983 /* If first arg is constant zero, return it. */
3984 if (integer_zerop (arg0))
3986 case TRUTH_AND_EXPR:
3987 /* If either arg is constant true, drop it. */
3988 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
3989 return non_lvalue (arg1);
3990 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
3991 return non_lvalue (arg0);
3992 /* If second arg is constant zero, result is zero, but first arg
3993 must be evaluated. */
3994 if (integer_zerop (arg1))
3995 return omit_one_operand (type, arg1, arg0);
3998 /* Check for the possibility of merging component references. If our
3999 lhs is another similar operation, try to merge its rhs with our
4000 rhs. Then try to merge our lhs and rhs. */
4003 if (TREE_CODE (arg0) == code)
4005 tem = fold_truthop (code, type,
4006 TREE_OPERAND (arg0, 1), arg1);
4008 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
4011 tem = fold_truthop (code, type, arg0, arg1);
4017 case TRUTH_ORIF_EXPR:
4018 /* Note that the operands of this must be ints
4019 and their values must be 0 or true.
4020 ("true" is a fixed value perhaps depending on the language.) */
4021 /* If first arg is constant true, return it. */
4022 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
4025 /* If either arg is constant zero, drop it. */
4026 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
4027 return non_lvalue (arg1);
4028 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
4029 return non_lvalue (arg0);
4030 /* If second arg is constant true, result is true, but we must
4031 evaluate first arg. */
4032 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
4033 return omit_one_operand (type, arg1, arg0);
4036 case TRUTH_XOR_EXPR:
4037 /* If either arg is constant zero, drop it. */
4038 if (integer_zerop (arg0))
4039 return non_lvalue (arg1);
4040 if (integer_zerop (arg1))
4041 return non_lvalue (arg0);
4042 /* If either arg is constant true, this is a logical inversion. */
4043 if (integer_onep (arg0))
4044 return non_lvalue (invert_truthvalue (arg1));
4045 if (integer_onep (arg1))
4046 return non_lvalue (invert_truthvalue (arg0));
4055 /* If one arg is a constant integer, put it last. */
4056 if (TREE_CODE (arg0) == INTEGER_CST
4057 && TREE_CODE (arg1) != INTEGER_CST)
4059 TREE_OPERAND (t, 0) = arg1;
4060 TREE_OPERAND (t, 1) = arg0;
4061 arg0 = TREE_OPERAND (t, 0);
4062 arg1 = TREE_OPERAND (t, 1);
4063 code = swap_tree_comparison (code);
4064 TREE_SET_CODE (t, code);
4067 /* Convert foo++ == CONST into ++foo == CONST + INCR.
4068 First, see if one arg is constant; find the constant arg
4069 and the other one. */
4071 tree constop = 0, varop;
4074 if (TREE_CONSTANT (arg1))
4075 constoploc = &TREE_OPERAND (t, 1), constop = arg1, varop = arg0;
4076 if (TREE_CONSTANT (arg0))
4077 constoploc = &TREE_OPERAND (t, 0), constop = arg0, varop = arg1;
4079 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
4081 /* This optimization is invalid for ordered comparisons
4082 if CONST+INCR overflows or if foo+incr might overflow.
4083 This optimization is invalid for floating point due to rounding.
4084 For pointer types we assume overflow doesn't happen. */
4085 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4086 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4087 && (code == EQ_EXPR || code == NE_EXPR)))
4090 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
4091 constop, TREE_OPERAND (varop, 1)));
4092 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
4093 *constoploc = newconst;
4097 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
4099 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
4100 || (! FLOAT_TYPE_P (TREE_TYPE (varop))
4101 && (code == EQ_EXPR || code == NE_EXPR)))
4104 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
4105 constop, TREE_OPERAND (varop, 1)));
4106 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
4107 *constoploc = newconst;
4113 /* Change X >= CST to X > (CST - 1) if CST is positive. */
4114 if (TREE_CODE (arg1) == INTEGER_CST
4115 && TREE_CODE (arg0) != INTEGER_CST
4116 && ! tree_int_cst_lt (arg1, integer_one_node))
4118 switch (TREE_CODE (t))
4122 TREE_SET_CODE (t, code);
4123 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4124 TREE_OPERAND (t, 1) = arg1;
4129 TREE_SET_CODE (t, code);
4130 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
4131 TREE_OPERAND (t, 1) = arg1;
4135 /* If this is an EQ or NE comparison with zero and ARG0 is
4136 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
4137 two operations, but the latter can be done in one less insn
4138 one machine that have only two-operand insns or on which a
4139 constant cannot be the first operand. */
4140 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
4141 && TREE_CODE (arg0) == BIT_AND_EXPR)
4143 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
4144 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
4146 fold (build (code, type,
4147 build (BIT_AND_EXPR, TREE_TYPE (arg0),
4149 TREE_TYPE (TREE_OPERAND (arg0, 0)),
4150 TREE_OPERAND (arg0, 1),
4151 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
4152 convert (TREE_TYPE (arg0),
4155 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
4156 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
4158 fold (build (code, type,
4159 build (BIT_AND_EXPR, TREE_TYPE (arg0),
4161 TREE_TYPE (TREE_OPERAND (arg0, 1)),
4162 TREE_OPERAND (arg0, 0),
4163 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
4164 convert (TREE_TYPE (arg0),
4169 /* If this is an NE or EQ comparison of zero against the result of a
4170 signed MOD operation, make the MOD operation unsigned since it
4171 is simpler and equivalent. */
4172 if ((code == NE_EXPR || code == EQ_EXPR)
4173 && integer_zerop (arg1)
4174 && ! TREE_UNSIGNED (TREE_TYPE (arg0))
4175 && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
4176 || TREE_CODE (arg0) == CEIL_MOD_EXPR
4177 || TREE_CODE (arg0) == FLOOR_MOD_EXPR
4178 || TREE_CODE (arg0) == ROUND_MOD_EXPR))
4180 tree newtype = unsigned_type (TREE_TYPE (arg0));
4181 tree newmod = build (TREE_CODE (arg0), newtype,
4182 convert (newtype, TREE_OPERAND (arg0, 0)),
4183 convert (newtype, TREE_OPERAND (arg0, 1)));
4185 return build (code, type, newmod, convert (newtype, arg1));
4188 /* If this is an NE comparison of zero with an AND of one, remove the
4189 comparison since the AND will give the correct value. */
4190 if (code == NE_EXPR && integer_zerop (arg1)
4191 && TREE_CODE (arg0) == BIT_AND_EXPR
4192 && integer_onep (TREE_OPERAND (arg0, 1)))
4193 return convert (type, arg0);
4195 /* If we have (A & C) == C where C is a power of 2, convert this into
4196 (A & C) != 0. Similarly for NE_EXPR. */
4197 if ((code == EQ_EXPR || code == NE_EXPR)
4198 && TREE_CODE (arg0) == BIT_AND_EXPR
4199 && integer_pow2p (TREE_OPERAND (arg0, 1))
4200 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
4201 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
4202 arg0, integer_zero_node);
4204 /* Simplify comparison of something with itself. (For IEEE
4205 floating-point, we can only do some of these simplifications.) */
4206 if (operand_equal_p (arg0, arg1, 0))
4213 if (INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
4215 t = build_int_2 (1, 0);
4216 TREE_TYPE (t) = type;
4220 TREE_SET_CODE (t, code);
4224 /* For NE, we can only do this simplification if integer. */
4225 if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)))
4227 /* ... fall through ... */
4230 t = build_int_2 (0, 0);
4231 TREE_TYPE (t) = type;
4236 /* An unsigned comparison against 0 can be simplified. */
4237 if (integer_zerop (arg1)
4238 && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
4239 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
4240 && TREE_UNSIGNED (TREE_TYPE (arg1)))
4242 switch (TREE_CODE (t))
4246 TREE_SET_CODE (t, NE_EXPR);
4250 TREE_SET_CODE (t, EQ_EXPR);
4253 return omit_one_operand (type,
4254 convert (type, integer_one_node),
4257 return omit_one_operand (type,
4258 convert (type, integer_zero_node),
4263 /* If we are comparing an expression that just has comparisons
4264 of two integer values, arithmetic expressions of those comparisons,
4265 and constants, we can simplify it. There are only three cases
4266 to check: the two values can either be equal, the first can be
4267 greater, or the second can be greater. Fold the expression for
4268 those three values. Since each value must be 0 or 1, we have
4269 eight possibilities, each of which corresponds to the constant 0
4270 or 1 or one of the six possible comparisons.
4272 This handles common cases like (a > b) == 0 but also handles
4273 expressions like ((x > y) - (y > x)) > 0, which supposedly
4274 occur in macroized code. */
4276 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
4278 tree cval1 = 0, cval2 = 0;
4280 if (twoval_comparison_p (arg0, &cval1, &cval2)
4281 /* Don't handle degenerate cases here; they should already
4282 have been handled anyway. */
4283 && cval1 != 0 && cval2 != 0
4284 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
4285 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
4286 && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
4287 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
4288 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
4290 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
4291 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
4293 /* We can't just pass T to eval_subst in case cval1 or cval2
4294 was the same as ARG1. */
4297 = fold (build (code, type,
4298 eval_subst (arg0, cval1, maxval, cval2, minval),
4301 = fold (build (code, type,
4302 eval_subst (arg0, cval1, maxval, cval2, maxval),
4305 = fold (build (code, type,
4306 eval_subst (arg0, cval1, minval, cval2, maxval),
4309 /* All three of these results should be 0 or 1. Confirm they
4310 are. Then use those values to select the proper code
4313 if ((integer_zerop (high_result)
4314 || integer_onep (high_result))
4315 && (integer_zerop (equal_result)
4316 || integer_onep (equal_result))
4317 && (integer_zerop (low_result)
4318 || integer_onep (low_result)))
4320 /* Make a 3-bit mask with the high-order bit being the
4321 value for `>', the next for '=', and the low for '<'. */
4322 switch ((integer_onep (high_result) * 4)
4323 + (integer_onep (equal_result) * 2)
4324 + integer_onep (low_result))
4328 return omit_one_operand (type, integer_zero_node, arg0);
4349 return omit_one_operand (type, integer_one_node, arg0);
4352 return fold (build (code, type, cval1, cval2));
4357 /* If this is a comparison of a field, we may be able to simplify it. */
4358 if ((TREE_CODE (arg0) == COMPONENT_REF
4359 || TREE_CODE (arg0) == BIT_FIELD_REF)
4360 && (code == EQ_EXPR || code == NE_EXPR)
4361 /* Handle the constant case even without -O
4362 to make sure the warnings are given. */
4363 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
4365 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
4369 /* From here on, the only cases we handle are when the result is
4370 known to be a constant.
4372 To compute GT, swap the arguments and do LT.
4373 To compute GE, do LT and invert the result.
4374 To compute LE, swap the arguments, do LT and invert the result.
4375 To compute NE, do EQ and invert the result.
4377 Therefore, the code below must handle only EQ and LT. */
4379 if (code == LE_EXPR || code == GT_EXPR)
4381 tem = arg0, arg0 = arg1, arg1 = tem;
4382 code = swap_tree_comparison (code);
4385 /* Note that it is safe to invert for real values here because we
4386 will check below in the one case that it matters. */
4389 if (code == NE_EXPR || code == GE_EXPR)
4392 code = invert_tree_comparison (code);
4395 /* Compute a result for LT or EQ if args permit;
4396 otherwise return T. */
4397 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
4399 if (code == EQ_EXPR)
4400 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
4401 == TREE_INT_CST_LOW (arg1))
4402 && (TREE_INT_CST_HIGH (arg0)
4403 == TREE_INT_CST_HIGH (arg1)),
4406 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
4407 ? INT_CST_LT_UNSIGNED (arg0, arg1)
4408 : INT_CST_LT (arg0, arg1)),
4412 /* Assume a nonexplicit constant cannot equal an explicit one,
4413 since such code would be undefined anyway.
4414 Exception: on sysvr4, using #pragma weak,
4415 a label can come out as 0. */
4416 else if (TREE_CODE (arg1) == INTEGER_CST
4417 && !integer_zerop (arg1)
4418 && TREE_CONSTANT (arg0)
4419 && TREE_CODE (arg0) == ADDR_EXPR
4421 t1 = build_int_2 (0, 0);
4423 /* Two real constants can be compared explicitly. */
4424 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
4426 /* If either operand is a NaN, the result is false with two
4427 exceptions: First, an NE_EXPR is true on NaNs, but that case
4428 is already handled correctly since we will be inverting the
4429 result for NE_EXPR. Second, if we had inverted a LE_EXPR
4430 or a GE_EXPR into a LT_EXPR, we must return true so that it
4431 will be inverted into false. */
4433 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
4434 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
4435 t1 = build_int_2 (invert && code == LT_EXPR, 0);
4437 else if (code == EQ_EXPR)
4438 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
4439 TREE_REAL_CST (arg1)),
4442 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
4443 TREE_REAL_CST (arg1)),
4447 if (t1 == NULL_TREE)
4451 TREE_INT_CST_LOW (t1) ^= 1;
4453 TREE_TYPE (t1) = type;
4457 if (TREE_CODE (arg0) == INTEGER_CST)
4458 return TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1));
4459 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
4460 return omit_one_operand (type, arg1, arg0);
4462 /* If the second operand is zero, invert the comparison and swap
4463 the second and third operands. Likewise if the second operand
4464 is constant and the third is not or if the third operand is
4465 equivalent to the first operand of the comparison. */
4467 if (integer_zerop (arg1)
4468 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
4469 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4470 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
4471 TREE_OPERAND (t, 2),
4472 TREE_OPERAND (arg0, 1))))
4474 /* See if this can be inverted. If it can't, possibly because
4475 it was a floating-point inequality comparison, don't do
4477 tem = invert_truthvalue (arg0);
4479 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
4481 arg0 = TREE_OPERAND (t, 0) = tem;
4482 TREE_OPERAND (t, 1) = TREE_OPERAND (t, 2);
4483 TREE_OPERAND (t, 2) = arg1;
4484 arg1 = TREE_OPERAND (t, 1);
4488 /* If we have A op B ? A : C, we may be able to convert this to a
4489 simpler expression, depending on the operation and the values
4490 of B and C. IEEE floating point prevents this though,
4491 because A or B might be -0.0 or a NaN. */
4493 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4494 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4495 || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0))))
4496 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
4497 arg1, TREE_OPERAND (arg0, 1)))
4499 tree arg2 = TREE_OPERAND (t, 2);
4500 enum tree_code comp_code = TREE_CODE (arg0);
4502 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
4503 depending on the comparison operation. */
4504 if (integer_zerop (TREE_OPERAND (arg0, 1))
4505 && TREE_CODE (arg2) == NEGATE_EXPR
4506 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
4510 return fold (build1 (NEGATE_EXPR, type, arg1));
4512 return convert (type, arg1);
4515 return fold (build1 (ABS_EXPR, type, arg1));
4518 return fold (build1 (NEGATE_EXPR, type,
4519 fold (build1 (ABS_EXPR, type, arg1))));
4522 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
4525 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
4527 if (comp_code == NE_EXPR)
4528 return convert (type, arg1);
4529 else if (comp_code == EQ_EXPR)
4530 return convert (type, integer_zero_node);
4533 /* If this is A op B ? A : B, this is either A, B, min (A, B),
4534 or max (A, B), depending on the operation. */
4536 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
4537 arg2, TREE_OPERAND (arg0, 0)))
4541 return convert (type, arg2);
4543 return convert (type, arg1);
4546 return fold (build (MIN_EXPR, type, arg1, arg2));
4549 return fold (build (MAX_EXPR, type, arg1, arg2));
4552 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4553 we might still be able to simplify this. For example,
4554 if C1 is one less or one more than C2, this might have started
4555 out as a MIN or MAX and been transformed by this function.
4556 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4558 if (INTEGRAL_TYPE_P (type)
4559 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4560 && TREE_CODE (arg2) == INTEGER_CST)
4564 /* We can replace A with C1 in this case. */
4565 arg1 = TREE_OPERAND (t, 1)
4566 = convert (type, TREE_OPERAND (arg0, 1));
4570 /* If C1 is C2 + 1, this is min(A, C2). */
4571 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
4572 && operand_equal_p (TREE_OPERAND (arg0, 1),
4573 const_binop (PLUS_EXPR, arg2,
4574 integer_one_node, 0), 1))
4575 return fold (build (MIN_EXPR, type, arg1, arg2));
4579 /* If C1 is C2 - 1, this is min(A, C2). */
4580 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
4581 && operand_equal_p (TREE_OPERAND (arg0, 1),
4582 const_binop (MINUS_EXPR, arg2,
4583 integer_one_node, 0), 1))
4584 return fold (build (MIN_EXPR, type, arg1, arg2));
4588 /* If C1 is C2 - 1, this is max(A, C2). */
4589 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
4590 && operand_equal_p (TREE_OPERAND (arg0, 1),
4591 const_binop (MINUS_EXPR, arg2,
4592 integer_one_node, 0), 1))
4593 return fold (build (MAX_EXPR, type, arg1, arg2));
4597 /* If C1 is C2 + 1, this is max(A, C2). */
4598 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
4599 && operand_equal_p (TREE_OPERAND (arg0, 1),
4600 const_binop (PLUS_EXPR, arg2,
4601 integer_one_node, 0), 1))
4602 return fold (build (MAX_EXPR, type, arg1, arg2));
4607 /* Convert A ? 1 : 0 to simply A. */
4608 if (integer_onep (TREE_OPERAND (t, 1))
4609 && integer_zerop (TREE_OPERAND (t, 2))
4610 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
4611 call to fold will try to move the conversion inside
4612 a COND, which will recurse. In that case, the COND_EXPR
4613 is probably the best choice, so leave it alone. */
4614 && type == TREE_TYPE (arg0))
4618 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
4619 operation is simply A & 2. */
4621 if (integer_zerop (TREE_OPERAND (t, 2))
4622 && TREE_CODE (arg0) == NE_EXPR
4623 && integer_zerop (TREE_OPERAND (arg0, 1))
4624 && integer_pow2p (arg1)
4625 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
4626 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
4628 return convert (type, TREE_OPERAND (arg0, 0));
4633 /* When pedantic, a compound expression can be neither an lvalue
4634 nor an integer constant expression. */
4635 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
4637 /* Don't let (0, 0) be null pointer constant. */
4638 if (integer_zerop (arg1))
4639 return non_lvalue (arg1);
4644 return build_complex (arg0, arg1);
4648 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4650 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4651 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
4652 TREE_OPERAND (arg0, 1));
4653 else if (TREE_CODE (arg0) == COMPLEX_CST)
4654 return TREE_REALPART (arg0);
4655 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4656 return fold (build (TREE_CODE (arg0), type,
4657 fold (build1 (REALPART_EXPR, type,
4658 TREE_OPERAND (arg0, 0))),
4659 fold (build1 (REALPART_EXPR,
4660 type, TREE_OPERAND (arg0, 1)))));
4664 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4665 return convert (type, integer_zero_node);
4666 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4667 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
4668 TREE_OPERAND (arg0, 0));
4669 else if (TREE_CODE (arg0) == COMPLEX_CST)
4670 return TREE_IMAGPART (arg0);
4671 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4672 return fold (build (TREE_CODE (arg0), type,
4673 fold (build1 (IMAGPART_EXPR, type,
4674 TREE_OPERAND (arg0, 0))),
4675 fold (build1 (IMAGPART_EXPR, type,
4676 TREE_OPERAND (arg0, 1)))));
4681 } /* switch (code) */