1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992 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 void lshift_double ();
52 void rshift_double ();
53 void lrotate_double ();
54 void rrotate_double ();
55 static tree const_binop ();
61 /* Yield nonzero if a signed left shift of A by B bits overflows. */
62 #define left_shift_overflows(a, b) ((a) != ((a) << (b)) >> (b))
64 /* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow.
65 Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1.
66 Then this yields nonzero if overflow occurred during the addition.
67 Overflow occurs if A and B have the same sign, but A and SUM differ in sign.
68 Use `^' to test whether signs differ, and `< 0' to isolate the sign. */
69 #define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
71 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
72 We do that by representing the two-word integer as MAX_SHORTS shorts,
73 with only 8 bits stored in each short, as a positive number. */
75 /* Unpack a two-word integer into MAX_SHORTS shorts.
76 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
77 SHORTS points to the array of shorts. */
80 encode (shorts, low, hi)
82 HOST_WIDE_INT low, hi;
86 for (i = 0; i < MAX_SHORTS / 2; i++)
88 shorts[i] = (low >> (i * 8)) & 0xff;
89 shorts[i + MAX_SHORTS / 2] = (hi >> (i * 8) & 0xff);
93 /* Pack an array of MAX_SHORTS shorts into a two-word integer.
94 SHORTS points to the array of shorts.
95 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
98 decode (shorts, low, hi)
100 HOST_WIDE_INT *low, *hi;
103 HOST_WIDE_INT lv = 0, hv = 0;
105 for (i = 0; i < MAX_SHORTS / 2; i++)
107 lv |= (HOST_WIDE_INT) shorts[i] << (i * 8);
108 hv |= (HOST_WIDE_INT) shorts[i + MAX_SHORTS / 2] << (i * 8);
114 /* Make the integer constant T valid for its type
115 by setting to 0 or 1 all the bits in the constant
116 that don't belong in the type.
117 Yield 1 if a signed overflow occurs, 0 otherwise.
118 If OVERFLOW is nonzero, a signed overflow has already occurred
119 in calculating T, so propagate it. */
122 force_fit_type (t, overflow)
126 HOST_WIDE_INT low, high;
129 if (TREE_CODE (t) != INTEGER_CST)
132 low = TREE_INT_CST_LOW (t);
133 high = TREE_INT_CST_HIGH (t);
135 if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
138 prec = TYPE_PRECISION (TREE_TYPE (t));
140 /* First clear all bits that are beyond the type's precision. */
142 if (prec == 2 * HOST_BITS_PER_WIDE_INT)
144 else if (prec > HOST_BITS_PER_WIDE_INT)
146 TREE_INT_CST_HIGH (t)
147 &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
151 TREE_INT_CST_HIGH (t) = 0;
152 if (prec < HOST_BITS_PER_WIDE_INT)
153 TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec);
156 /* Unsigned types do not suffer sign extension or overflow. */
157 if (TREE_UNSIGNED (TREE_TYPE (t)))
160 /* If the value's sign bit is set, extend the sign. */
161 if (prec != 2 * HOST_BITS_PER_WIDE_INT
162 && (prec > HOST_BITS_PER_WIDE_INT
163 ? (TREE_INT_CST_HIGH (t)
164 & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1)))
165 : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1))))
167 /* Value is negative:
168 set to 1 all the bits that are outside this type's precision. */
169 if (prec > HOST_BITS_PER_WIDE_INT)
171 TREE_INT_CST_HIGH (t)
172 |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
176 TREE_INT_CST_HIGH (t) = -1;
177 if (prec < HOST_BITS_PER_WIDE_INT)
178 TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec);
182 /* Yield nonzero if signed overflow occurred. */
184 ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
188 /* Add two doubleword integers with doubleword result.
189 Each argument is given as two `HOST_WIDE_INT' pieces.
190 One argument is L1 and H1; the other, L2 and H2.
191 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
192 We use the 8-shorts representation internally. */
195 add_double (l1, h1, l2, h2, lv, hv)
196 HOST_WIDE_INT l1, h1, l2, h2;
197 HOST_WIDE_INT *lv, *hv;
199 short arg1[MAX_SHORTS];
200 short arg2[MAX_SHORTS];
201 register int carry = 0;
204 encode (arg1, l1, h1);
205 encode (arg2, l2, h2);
207 for (i = 0; i < MAX_SHORTS; i++)
209 carry += arg1[i] + arg2[i];
210 arg1[i] = carry & 0xff;
214 decode (arg1, lv, hv);
215 return overflow_sum_sign (h1, h2, *hv);
218 /* Negate a doubleword integer with doubleword result.
219 Return nonzero if the operation overflows, assuming it's signed.
220 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
221 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
222 We use the 8-shorts representation internally. */
225 neg_double (l1, h1, lv, hv)
226 HOST_WIDE_INT l1, h1;
227 HOST_WIDE_INT *lv, *hv;
233 return (*hv & h1) < 0;
243 /* Multiply two doubleword integers with doubleword result.
244 Return nonzero if the operation overflows, assuming it's signed.
245 Each argument is given as two `HOST_WIDE_INT' pieces.
246 One argument is L1 and H1; the other, L2 and H2.
247 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV.
248 We use the 8-shorts representation internally. */
251 mul_double (l1, h1, l2, h2, lv, hv)
252 HOST_WIDE_INT l1, h1, l2, h2;
253 HOST_WIDE_INT *lv, *hv;
255 short arg1[MAX_SHORTS];
256 short arg2[MAX_SHORTS];
257 short prod[MAX_SHORTS * 2];
258 register int carry = 0;
259 register int i, j, k;
260 HOST_WIDE_INT toplow, tophigh, neglow, neghigh;
262 /* These cases are used extensively, arising from pointer combinations. */
267 int overflow = left_shift_overflows (h1, 1);
268 unsigned HOST_WIDE_INT temp = l1 + l1;
269 *hv = (h1 << 1) + (temp < l1);
275 int overflow = left_shift_overflows (h1, 2);
276 unsigned HOST_WIDE_INT temp = l1 + l1;
277 h1 = (h1 << 2) + ((temp < l1) << 1);
287 int overflow = left_shift_overflows (h1, 3);
288 unsigned HOST_WIDE_INT temp = l1 + l1;
289 h1 = (h1 << 3) + ((temp < l1) << 2);
292 h1 += (temp < l1) << 1;
302 encode (arg1, l1, h1);
303 encode (arg2, l2, h2);
305 bzero (prod, sizeof prod);
307 for (i = 0; i < MAX_SHORTS; i++)
308 for (j = 0; j < MAX_SHORTS; j++)
311 carry = arg1[i] * arg2[j];
315 prod[k] = carry & 0xff;
321 decode (prod, lv, hv); /* This ignores
322 prod[MAX_SHORTS] -> prod[MAX_SHORTS*2-1] */
324 /* Check for overflow by calculating the top half of the answer in full;
325 it should agree with the low half's sign bit. */
326 decode (prod+MAX_SHORTS, &toplow, &tophigh);
329 neg_double (l2, h2, &neglow, &neghigh);
330 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
334 neg_double (l1, h1, &neglow, &neghigh);
335 add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
337 return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
340 /* Shift the doubleword integer in L1, H1 left by COUNT places
341 keeping only PREC bits of result.
342 Shift right if COUNT is negative.
343 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
344 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
347 lshift_double (l1, h1, count, prec, lv, hv, arith)
348 HOST_WIDE_INT l1, h1;
350 HOST_WIDE_INT *lv, *hv;
353 short arg1[MAX_SHORTS];
359 rshift_double (l1, h1, - count, prec, lv, hv, arith);
363 encode (arg1, l1, h1);
371 for (i = 0; i < MAX_SHORTS; i++)
373 carry += arg1[i] << 1;
374 arg1[i] = carry & 0xff;
380 decode (arg1, lv, hv);
383 /* Shift the doubleword integer in L1, H1 right by COUNT places
384 keeping only PREC bits of result. COUNT must be positive.
385 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
386 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
389 rshift_double (l1, h1, count, prec, lv, hv, arith)
390 HOST_WIDE_INT l1, h1, count, prec;
391 HOST_WIDE_INT *lv, *hv;
394 short arg1[MAX_SHORTS];
398 encode (arg1, l1, h1);
405 carry = arith && arg1[7] >> 7;
406 for (i = MAX_SHORTS - 1; i >= 0; i--)
410 arg1[i] = (carry >> 1) & 0xff;
415 decode (arg1, lv, hv);
418 /* Rotate the doubldword integer in L1, H1 left by COUNT places
419 keeping only PREC bits of result.
420 Rotate right if COUNT is negative.
421 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
424 lrotate_double (l1, h1, count, prec, lv, hv)
425 HOST_WIDE_INT l1, h1, count, prec;
426 HOST_WIDE_INT *lv, *hv;
428 short arg1[MAX_SHORTS];
434 rrotate_double (l1, h1, - count, prec, lv, hv);
438 encode (arg1, l1, h1);
443 carry = arg1[MAX_SHORTS - 1] >> 7;
446 for (i = 0; i < MAX_SHORTS; i++)
448 carry += arg1[i] << 1;
449 arg1[i] = carry & 0xff;
455 decode (arg1, lv, hv);
458 /* Rotate the doubleword integer in L1, H1 left by COUNT places
459 keeping only PREC bits of result. COUNT must be positive.
460 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
463 rrotate_double (l1, h1, count, prec, lv, hv)
464 HOST_WIDE_INT l1, h1, count, prec;
465 HOST_WIDE_INT *lv, *hv;
467 short arg1[MAX_SHORTS];
471 encode (arg1, l1, h1);
479 for (i = MAX_SHORTS - 1; i >= 0; i--)
483 arg1[i] = (carry >> 1) & 0xff;
488 decode (arg1, lv, hv);
491 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
492 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
493 CODE is a tree code for a kind of division, one of
494 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
496 It controls how the quotient is rounded to a integer.
497 Return nonzero if the operation overflows.
498 UNS nonzero says do unsigned division. */
501 div_and_round_double (code, uns,
502 lnum_orig, hnum_orig, lden_orig, hden_orig,
503 lquo, hquo, lrem, hrem)
506 HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */
507 HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */
508 HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem;
511 short num[MAX_SHORTS + 1]; /* extra element for scaling. */
512 short den[MAX_SHORTS], quo[MAX_SHORTS];
513 register int i, j, work;
514 register int carry = 0;
515 HOST_WIDE_INT lnum = lnum_orig;
516 HOST_WIDE_INT hnum = hnum_orig;
517 HOST_WIDE_INT lden = lden_orig;
518 HOST_WIDE_INT hden = hden_orig;
521 if ((hden == 0) && (lden == 0))
524 /* calculate quotient sign and convert operands to unsigned. */
530 /* (minimum integer) / (-1) is the only overflow case. */
531 if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1)
537 neg_double (lden, hden, &lden, &hden);
541 if (hnum == 0 && hden == 0)
542 { /* single precision */
544 /* This unsigned division rounds toward zero. */
545 *lquo = lnum / (unsigned HOST_WIDE_INT) lden;
550 { /* trivial case: dividend < divisor */
551 /* hden != 0 already checked. */
558 bzero (quo, sizeof quo);
560 bzero (num, sizeof num); /* to zero 9th element */
561 bzero (den, sizeof den);
563 encode (num, lnum, hnum);
564 encode (den, lden, hden);
566 /* This code requires more than just hden == 0.
567 We also have to require that we don't need more than three bytes
568 to hold CARRY. If we ever did need four bytes to hold it, we
569 would lose part of it when computing WORK on the next round. */
570 if (hden == 0 && (((unsigned HOST_WIDE_INT) lden << 8) >> 8) == lden)
571 { /* simpler algorithm */
572 /* hnum != 0 already checked. */
573 for (i = MAX_SHORTS - 1; i >= 0; i--)
575 work = num[i] + (carry << 8);
576 quo[i] = work / (unsigned HOST_WIDE_INT) lden;
577 carry = work % (unsigned HOST_WIDE_INT) lden;
580 else { /* full double precision,
581 with thanks to Don Knuth's
582 "Seminumerical Algorithms". */
584 int quo_est, scale, num_hi_sig, den_hi_sig, quo_hi_sig;
586 /* Find the highest non-zero divisor digit. */
587 for (i = MAX_SHORTS - 1; ; i--)
592 for (i = MAX_SHORTS - 1; ; i--)
597 quo_hi_sig = num_hi_sig - den_hi_sig + 1;
599 /* Insure that the first digit of the divisor is at least BASE/2.
600 This is required by the quotient digit estimation algorithm. */
602 scale = BASE / (den[den_hi_sig] + 1);
603 if (scale > 1) { /* scale divisor and dividend */
605 for (i = 0; i <= MAX_SHORTS - 1; i++) {
606 work = (num[i] * scale) + carry;
607 num[i] = work & 0xff;
609 if (num[i] != 0) num_hi_sig = i;
612 for (i = 0; i <= MAX_SHORTS - 1; i++) {
613 work = (den[i] * scale) + carry;
614 den[i] = work & 0xff;
616 if (den[i] != 0) den_hi_sig = i;
621 for (i = quo_hi_sig; i > 0; i--) {
622 /* guess the next quotient digit, quo_est, by dividing the first
623 two remaining dividend digits by the high order quotient digit.
624 quo_est is never low and is at most 2 high. */
626 int num_hi; /* index of highest remaining dividend digit */
628 num_hi = i + den_hi_sig;
630 work = (num[num_hi] * BASE) + (num_hi > 0 ? num[num_hi - 1] : 0);
631 if (num[num_hi] != den[den_hi_sig]) {
632 quo_est = work / den[den_hi_sig];
638 /* refine quo_est so it's usually correct, and at most one high. */
639 while ((den[den_hi_sig - 1] * quo_est)
640 > (((work - (quo_est * den[den_hi_sig])) * BASE)
641 + ((num_hi - 1) > 0 ? num[num_hi - 2] : 0)))
644 /* Try QUO_EST as the quotient digit, by multiplying the
645 divisor by QUO_EST and subtracting from the remaining dividend.
646 Keep in mind that QUO_EST is the I - 1st digit. */
650 for (j = 0; j <= den_hi_sig; j++)
654 work = num[i + j - 1] - (quo_est * den[j]) + carry;
662 num[i + j - 1] = digit;
665 /* if quo_est was high by one, then num[i] went negative and
666 we need to correct things. */
671 carry = 0; /* add divisor back in */
672 for (j = 0; j <= den_hi_sig; j++)
674 work = num[i + j - 1] + den[j] + carry;
684 num[i + j - 1] = work;
686 num [num_hi] += carry;
689 /* store the quotient digit. */
690 quo[i - 1] = quo_est;
694 decode (quo, lquo, hquo);
697 /* if result is negative, make it so. */
699 neg_double (*lquo, *hquo, lquo, hquo);
701 /* compute trial remainder: rem = num - (quo * den) */
702 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
703 neg_double (*lrem, *hrem, lrem, hrem);
704 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
709 case TRUNC_MOD_EXPR: /* round toward zero */
710 case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
714 case FLOOR_MOD_EXPR: /* round toward negative infinity */
715 if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
718 add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
721 else return overflow;
725 case CEIL_MOD_EXPR: /* round toward positive infinity */
726 if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
728 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
731 else return overflow;
735 case ROUND_MOD_EXPR: /* round to closest integer */
737 HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem;
738 HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice;
740 /* get absolute values */
741 if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
742 if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den);
744 /* if (2 * abs (lrem) >= abs (lden)) */
745 mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
746 labs_rem, habs_rem, <wice, &htwice);
747 if (((unsigned HOST_WIDE_INT) habs_den
748 < (unsigned HOST_WIDE_INT) htwice)
749 || (((unsigned HOST_WIDE_INT) habs_den
750 == (unsigned HOST_WIDE_INT) htwice)
751 && ((HOST_WIDE_INT unsigned) labs_den
752 < (unsigned HOST_WIDE_INT) ltwice)))
756 add_double (*lquo, *hquo,
757 (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
760 add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
763 else return overflow;
771 /* compute true remainder: rem = num - (quo * den) */
772 mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
773 neg_double (*lrem, *hrem, lrem, hrem);
774 add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
778 #ifndef REAL_ARITHMETIC
779 /* Effectively truncate a real value to represent
780 the nearest possible value in a narrower mode.
781 The result is actually represented in the same data type as the argument,
782 but its value is usually different. */
785 real_value_truncate (mode, arg)
786 enum machine_mode mode;
790 /* Make sure the value is actually stored in memory before we turn off
794 REAL_VALUE_TYPE value;
795 jmp_buf handler, old_handler;
798 if (setjmp (handler))
800 error ("floating overflow");
803 handled = push_float_handler (handler, old_handler);
804 value = REAL_VALUE_TRUNCATE (mode, arg);
805 pop_float_handler (handled, old_handler);
809 #if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
811 /* Check for infinity in an IEEE double precision number. */
817 /* The IEEE 64-bit double format. */
822 unsigned exponent : 11;
823 unsigned mantissa1 : 20;
828 unsigned mantissa1 : 20;
829 unsigned exponent : 11;
835 if (u.big_endian.sign == 1)
838 return (u.big_endian.exponent == 2047
839 && u.big_endian.mantissa1 == 0
840 && u.big_endian.mantissa2 == 0);
845 return (u.little_endian.exponent == 2047
846 && u.little_endian.mantissa1 == 0
847 && u.little_endian.mantissa2 == 0);
851 /* Check whether an IEEE double precision number is a NaN. */
857 /* The IEEE 64-bit double format. */
862 unsigned exponent : 11;
863 unsigned mantissa1 : 20;
868 unsigned mantissa1 : 20;
869 unsigned exponent : 11;
875 if (u.big_endian.sign == 1)
878 return (u.big_endian.exponent == 2047
879 && (u.big_endian.mantissa1 != 0
880 || u.big_endian.mantissa2 != 0));
885 return (u.little_endian.exponent == 2047
886 && (u.little_endian.mantissa1 != 0
887 || u.little_endian.mantissa2 != 0));
891 /* Check for a negative IEEE double precision number. */
897 /* The IEEE 64-bit double format. */
902 unsigned exponent : 11;
903 unsigned mantissa1 : 20;
908 unsigned mantissa1 : 20;
909 unsigned exponent : 11;
915 if (u.big_endian.sign == 1)
918 return u.big_endian.sign;
923 return u.little_endian.sign;
926 #else /* Target not IEEE */
928 /* Let's assume other float formats don't have infinity.
929 (This can be overridden by redefining REAL_VALUE_ISINF.) */
937 /* Let's assume other float formats don't have NaNs.
938 (This can be overridden by redefining REAL_VALUE_ISNAN.) */
946 /* Let's assume other float formats don't have minus zero.
947 (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
954 #endif /* Target not IEEE */
955 #endif /* no REAL_ARITHMETIC */
957 /* Split a tree IN into a constant and a variable part
958 that could be combined with CODE to make IN.
959 CODE must be a commutative arithmetic operation.
960 Store the constant part into *CONP and the variable in &VARP.
961 Return 1 if this was done; zero means the tree IN did not decompose
964 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR.
965 Therefore, we must tell the caller whether the variable part
966 was subtracted. We do this by storing 1 or -1 into *VARSIGNP.
967 The value stored is the coefficient for the variable term.
968 The constant term we return should always be added;
969 we negate it if necessary. */
972 split_tree (in, code, varp, conp, varsignp)
978 register tree outtype = TREE_TYPE (in);
982 /* Strip any conversions that don't change the machine mode. */
983 while ((TREE_CODE (in) == NOP_EXPR
984 || TREE_CODE (in) == CONVERT_EXPR)
985 && (TYPE_MODE (TREE_TYPE (in))
986 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0)))))
987 in = TREE_OPERAND (in, 0);
989 if (TREE_CODE (in) == code
990 || (TREE_CODE (TREE_TYPE (in)) != REAL_TYPE
991 /* We can associate addition and subtraction together
992 (even though the C standard doesn't say so)
993 for integers because the value is not affected.
994 For reals, the value might be affected, so we can't. */
996 ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
997 || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
999 enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0));
1000 if (code == INTEGER_CST)
1002 *conp = TREE_OPERAND (in, 0);
1003 *varp = TREE_OPERAND (in, 1);
1004 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1005 && TREE_TYPE (*varp) != outtype)
1006 *varp = convert (outtype, *varp);
1007 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1010 if (TREE_CONSTANT (TREE_OPERAND (in, 1)))
1012 *conp = TREE_OPERAND (in, 1);
1013 *varp = TREE_OPERAND (in, 0);
1015 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1016 && TREE_TYPE (*varp) != outtype)
1017 *varp = convert (outtype, *varp);
1018 if (TREE_CODE (in) == MINUS_EXPR)
1020 /* If operation is subtraction and constant is second,
1021 must negate it to get an additive constant.
1022 And this cannot be done unless it is a manifest constant.
1023 It could also be the address of a static variable.
1024 We cannot negate that, so give up. */
1025 if (TREE_CODE (*conp) == INTEGER_CST)
1026 /* Subtracting from integer_zero_node loses for long long. */
1027 *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp));
1033 if (TREE_CONSTANT (TREE_OPERAND (in, 0)))
1035 *conp = TREE_OPERAND (in, 0);
1036 *varp = TREE_OPERAND (in, 1);
1037 if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype)
1038 && TREE_TYPE (*varp) != outtype)
1039 *varp = convert (outtype, *varp);
1040 *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1;
1047 /* Combine two constants NUM and ARG2 under operation CODE
1048 to produce a new constant.
1049 We assume ARG1 and ARG2 have the same data type,
1050 or at least are the same kind of constant and the same machine mode.
1052 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1055 const_binop (code, arg1, arg2, notrunc)
1056 enum tree_code code;
1057 register tree arg1, arg2;
1060 if (TREE_CODE (arg1) == INTEGER_CST)
1062 register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1);
1063 register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1);
1064 HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2);
1065 HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2);
1066 HOST_WIDE_INT low, hi;
1067 HOST_WIDE_INT garbagel, garbageh;
1069 int uns = TREE_UNSIGNED (TREE_TYPE (arg1));
1075 t = build_int_2 (int1l | int2l, int1h | int2h);
1079 t = build_int_2 (int1l ^ int2l, int1h ^ int2h);
1083 t = build_int_2 (int1l & int2l, int1h & int2h);
1086 case BIT_ANDTC_EXPR:
1087 t = build_int_2 (int1l & ~int2l, int1h & ~int2h);
1093 /* It's unclear from the C standard whether shifts can overflow.
1094 The following code ignores overflow; perhaps a C standard
1095 interpretation ruling is needed. */
1096 lshift_double (int1l, int1h, int2l,
1097 TYPE_PRECISION (TREE_TYPE (arg1)),
1100 t = build_int_2 (low, hi);
1101 TREE_TYPE (t) = TREE_TYPE (arg1);
1103 force_fit_type (t, 0);
1104 TREE_CONSTANT_OVERFLOW (t)
1105 = TREE_CONSTANT_OVERFLOW (arg1) | TREE_CONSTANT_OVERFLOW (arg2);
1111 lrotate_double (int1l, int1h, int2l,
1112 TYPE_PRECISION (TREE_TYPE (arg1)),
1114 t = build_int_2 (low, hi);
1121 if ((unsigned HOST_WIDE_INT) int2l < int1l)
1124 overflow = int2h < hi;
1126 t = build_int_2 (int2l, int2h);
1132 if ((unsigned HOST_WIDE_INT) int1l < int2l)
1135 overflow = int1h < hi;
1137 t = build_int_2 (int1l, int1h);
1140 overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
1141 t = build_int_2 (low, hi);
1145 if (int2h == 0 && int2l == 0)
1147 t = build_int_2 (int1l, int1h);
1150 neg_double (int2l, int2h, &low, &hi);
1151 add_double (int1l, int1h, low, hi, &low, &hi);
1152 overflow = overflow_sum_sign (hi, int2h, int1h);
1153 t = build_int_2 (low, hi);
1157 /* Optimize simple cases. */
1160 unsigned HOST_WIDE_INT temp;
1165 t = build_int_2 (0, 0);
1168 t = build_int_2 (int2l, int2h);
1171 overflow = left_shift_overflows (int2h, 1);
1172 temp = int2l + int2l;
1173 int2h = (int2h << 1) + (temp < int2l);
1174 t = build_int_2 (temp, int2h);
1176 #if 0 /* This code can lose carries. */
1178 temp = int2l + int2l + int2l;
1179 int2h = int2h * 3 + (temp < int2l);
1180 t = build_int_2 (temp, int2h);
1184 overflow = left_shift_overflows (int2h, 2);
1185 temp = int2l + int2l;
1186 int2h = (int2h << 2) + ((temp < int2l) << 1);
1189 int2h += (temp < int2l);
1190 t = build_int_2 (temp, int2h);
1193 overflow = left_shift_overflows (int2h, 3);
1194 temp = int2l + int2l;
1195 int2h = (int2h << 3) + ((temp < int2l) << 2);
1198 int2h += (temp < int2l) << 1;
1201 int2h += (temp < int2l);
1202 t = build_int_2 (temp, int2h);
1213 t = build_int_2 (0, 0);
1218 t = build_int_2 (int1l, int1h);
1223 overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
1224 t = build_int_2 (low, hi);
1227 case TRUNC_DIV_EXPR:
1228 case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
1229 case EXACT_DIV_EXPR:
1230 /* This is a shortcut for a common special case.
1231 It reduces the number of tree nodes generated
1233 if (int2h == 0 && int2l > 0
1234 && TREE_TYPE (arg1) == sizetype
1235 && int1h == 0 && int1l >= 0)
1237 if (code == CEIL_DIV_EXPR)
1239 return size_int (int1l / int2l);
1241 case ROUND_DIV_EXPR:
1242 if (int2h == 0 && int2l == 1)
1244 t = build_int_2 (int1l, int1h);
1247 if (int1l == int2l && int1h == int2h)
1249 if ((int1l | int1h) == 0)
1251 t = build_int_2 (1, 0);
1254 overflow = div_and_round_double (code, uns,
1255 int1l, int1h, int2l, int2h,
1256 &low, &hi, &garbagel, &garbageh);
1257 t = build_int_2 (low, hi);
1260 case TRUNC_MOD_EXPR: case ROUND_MOD_EXPR:
1261 case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
1262 overflow = div_and_round_double (code, uns,
1263 int1l, int1h, int2l, int2h,
1264 &garbagel, &garbageh, &low, &hi);
1265 t = build_int_2 (low, hi);
1272 low = (((unsigned HOST_WIDE_INT) int1h
1273 < (unsigned HOST_WIDE_INT) int2h)
1274 || (((unsigned HOST_WIDE_INT) int1h
1275 == (unsigned HOST_WIDE_INT) int2h)
1276 && ((unsigned HOST_WIDE_INT) int1l
1277 < (unsigned HOST_WIDE_INT) int2l)));
1281 low = ((int1h < int2h)
1282 || ((int1h == int2h)
1283 && ((unsigned HOST_WIDE_INT) int1l
1284 < (unsigned HOST_WIDE_INT) int2l)));
1286 if (low == (code == MIN_EXPR))
1287 t = build_int_2 (int1l, int1h);
1289 t = build_int_2 (int2l, int2h);
1296 TREE_TYPE (t) = TREE_TYPE (arg1);
1297 TREE_CONSTANT_OVERFLOW (t)
1298 = ((notrunc ? !uns && overflow : force_fit_type (t, overflow))
1299 | TREE_CONSTANT_OVERFLOW (arg1)
1300 | TREE_CONSTANT_OVERFLOW (arg2));
1303 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1304 if (TREE_CODE (arg1) == REAL_CST)
1308 REAL_VALUE_TYPE value;
1311 d1 = TREE_REAL_CST (arg1);
1312 d2 = TREE_REAL_CST (arg2);
1313 if (setjmp (float_error))
1315 pedwarn ("floating overflow in constant expression");
1316 return build (code, TREE_TYPE (arg1), arg1, arg2);
1318 set_float_handler (float_error);
1320 #ifdef REAL_ARITHMETIC
1321 REAL_ARITHMETIC (value, code, d1, d2);
1338 #ifndef REAL_INFINITY
1347 value = MIN (d1, d2);
1351 value = MAX (d1, d2);
1357 #endif /* no REAL_ARITHMETIC */
1358 t = build_real (TREE_TYPE (arg1),
1359 real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value));
1360 set_float_handler (NULL_PTR);
1363 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1364 if (TREE_CODE (arg1) == COMPLEX_CST)
1366 register tree r1 = TREE_REALPART (arg1);
1367 register tree i1 = TREE_IMAGPART (arg1);
1368 register tree r2 = TREE_REALPART (arg2);
1369 register tree i2 = TREE_IMAGPART (arg2);
1375 t = build_complex (const_binop (PLUS_EXPR, r1, r2, notrunc),
1376 const_binop (PLUS_EXPR, i1, i2, notrunc));
1380 t = build_complex (const_binop (MINUS_EXPR, r1, r2, notrunc),
1381 const_binop (MINUS_EXPR, i1, i2, notrunc));
1385 t = build_complex (const_binop (MINUS_EXPR,
1386 const_binop (MULT_EXPR,
1388 const_binop (MULT_EXPR,
1391 const_binop (PLUS_EXPR,
1392 const_binop (MULT_EXPR,
1394 const_binop (MULT_EXPR,
1401 register tree magsquared
1402 = const_binop (PLUS_EXPR,
1403 const_binop (MULT_EXPR, r2, r2, notrunc),
1404 const_binop (MULT_EXPR, i2, i2, notrunc),
1406 t = build_complex (const_binop (RDIV_EXPR,
1407 const_binop (PLUS_EXPR,
1408 const_binop (MULT_EXPR, r1, r2, notrunc),
1409 const_binop (MULT_EXPR, i1, i2, notrunc),
1411 magsquared, notrunc),
1412 const_binop (RDIV_EXPR,
1413 const_binop (MINUS_EXPR,
1414 const_binop (MULT_EXPR, i1, r2, notrunc),
1415 const_binop (MULT_EXPR, r1, i2, notrunc),
1417 magsquared, notrunc));
1424 TREE_TYPE (t) = TREE_TYPE (arg1);
1430 /* Return an INTEGER_CST with value V and type from `sizetype'. */
1434 unsigned int number;
1437 /* Type-size nodes already made for small sizes. */
1438 static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1];
1440 if (number >= 0 && number < 2*HOST_BITS_PER_WIDE_INT + 1
1441 && size_table[number] != 0)
1442 return size_table[number];
1443 if (number >= 0 && number < 2*HOST_BITS_PER_WIDE_INT + 1)
1445 push_obstacks_nochange ();
1446 /* Make this a permanent node. */
1447 end_temporary_allocation ();
1448 t = build_int_2 (number, 0);
1449 TREE_TYPE (t) = sizetype;
1450 size_table[number] = t;
1455 t = build_int_2 (number, 0);
1456 TREE_TYPE (t) = sizetype;
1461 /* Combine operands OP1 and OP2 with arithmetic operation CODE.
1462 CODE is a tree code. Data type is taken from `sizetype',
1463 If the operands are constant, so is the result. */
1466 size_binop (code, arg0, arg1)
1467 enum tree_code code;
1470 /* Handle the special case of two integer constants faster. */
1471 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
1473 /* And some specific cases even faster than that. */
1474 if (code == PLUS_EXPR
1475 && TREE_INT_CST_LOW (arg0) == 0
1476 && TREE_INT_CST_HIGH (arg0) == 0)
1478 if (code == MINUS_EXPR
1479 && TREE_INT_CST_LOW (arg1) == 0
1480 && TREE_INT_CST_HIGH (arg1) == 0)
1482 if (code == MULT_EXPR
1483 && TREE_INT_CST_LOW (arg0) == 1
1484 && TREE_INT_CST_HIGH (arg0) == 0)
1486 /* Handle general case of two integer constants. */
1487 return const_binop (code, arg0, arg1, 1);
1490 if (arg0 == error_mark_node || arg1 == error_mark_node)
1491 return error_mark_node;
1493 return fold (build (code, sizetype, arg0, arg1));
1496 /* Given T, a tree representing type conversion of ARG1, a constant,
1497 return a constant tree representing the result of conversion. */
1500 fold_convert (t, arg1)
1504 register tree type = TREE_TYPE (t);
1506 if (TREE_CODE (type) == POINTER_TYPE
1507 || TREE_CODE (type) == INTEGER_TYPE
1508 || TREE_CODE (type) == ENUMERAL_TYPE)
1510 if (TREE_CODE (arg1) == INTEGER_CST)
1512 /* Given an integer constant, make new constant with new type,
1513 appropriately sign-extended or truncated. */
1514 t = build_int_2 (TREE_INT_CST_LOW (arg1),
1515 TREE_INT_CST_HIGH (arg1));
1516 TREE_TYPE (t) = type;
1517 /* Indicate an overflow if (1) ARG1 already overflowed,
1518 or (2) ARG1 is a too-large unsigned value and T is signed,
1519 or (3) force_fit_type indicates an overflow.
1520 force_fit_type can't detect (2), since it sees only T's type. */
1521 TREE_CONSTANT_OVERFLOW (t) =
1522 (TREE_CONSTANT_OVERFLOW (arg1)
1523 | (TREE_INT_CST_HIGH (arg1) < 0
1524 & TREE_UNSIGNED (type) < TREE_UNSIGNED (TREE_TYPE (arg1)))
1525 | force_fit_type (t, 0));
1527 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1528 else if (TREE_CODE (arg1) == REAL_CST)
1530 REAL_VALUE_TYPE l, x, u;
1532 l = real_value_from_int_cst (TYPE_MIN_VALUE (type));
1533 x = TREE_REAL_CST (arg1);
1534 u = real_value_from_int_cst (TYPE_MAX_VALUE (type));
1536 /* See if X will be in range after truncation towards 0.
1537 To compensate for truncation, move the bounds away from 0,
1538 but reject if X exactly equals the adjusted bounds. */
1539 #ifdef REAL_ARITHMETIC
1540 REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
1541 REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
1546 if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u)))
1548 pedwarn ("real constant out of range for integer conversion");
1551 #ifndef REAL_ARITHMETIC
1554 HOST_WIDE_INT low, high;
1555 HOST_WIDE_INT half_word
1556 = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
1558 d = TREE_REAL_CST (arg1);
1562 high = (HOST_WIDE_INT) (d / half_word / half_word);
1563 d -= (REAL_VALUE_TYPE) high * half_word * half_word;
1564 if (d >= (REAL_VALUE_TYPE) half_word * half_word / 2)
1566 low = d - (REAL_VALUE_TYPE) half_word * half_word / 2;
1567 low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
1570 low = (HOST_WIDE_INT) d;
1571 if (TREE_REAL_CST (arg1) < 0)
1572 neg_double (low, high, &low, &high);
1573 t = build_int_2 (low, high);
1577 HOST_WIDE_INT low, high;
1578 REAL_VALUE_TO_INT (&low, &high, (TREE_REAL_CST (arg1)));
1579 t = build_int_2 (low, high);
1582 TREE_TYPE (t) = type;
1583 force_fit_type (t, 0);
1585 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1586 TREE_TYPE (t) = type;
1588 else if (TREE_CODE (type) == REAL_TYPE)
1590 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1591 if (TREE_CODE (arg1) == INTEGER_CST)
1592 return build_real_from_int_cst (type, arg1);
1593 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1594 if (TREE_CODE (arg1) == REAL_CST)
1596 if (setjmp (float_error))
1598 pedwarn ("floating overflow in constant expression");
1601 set_float_handler (float_error);
1603 t = build_real (type, real_value_truncate (TYPE_MODE (type),
1604 TREE_REAL_CST (arg1)));
1605 set_float_handler (NULL_PTR);
1609 TREE_CONSTANT (t) = 1;
1613 /* Return an expr equal to X but certainly not valid as an lvalue.
1614 Also make sure it is not valid as an null pointer constant. */
1622 /* These things are certainly not lvalues. */
1623 if (TREE_CODE (x) == NON_LVALUE_EXPR
1624 || TREE_CODE (x) == INTEGER_CST
1625 || TREE_CODE (x) == REAL_CST
1626 || TREE_CODE (x) == STRING_CST
1627 || TREE_CODE (x) == ADDR_EXPR)
1629 if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x))
1631 /* Use NOP_EXPR instead of NON_LVALUE_EXPR
1632 so convert_for_assignment won't strip it.
1633 This is so this 0 won't be treated as a null pointer constant. */
1634 result = build1 (NOP_EXPR, TREE_TYPE (x), x);
1635 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1641 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
1642 TREE_CONSTANT (result) = TREE_CONSTANT (x);
1646 /* Given a tree comparison code, return the code that is the logical inverse
1647 of the given code. It is not safe to do this for floating-point
1648 comparisons, except for NE_EXPR and EQ_EXPR. */
1650 static enum tree_code
1651 invert_tree_comparison (code)
1652 enum tree_code code;
1673 /* Similar, but return the comparison that results if the operands are
1674 swapped. This is safe for floating-point. */
1676 static enum tree_code
1677 swap_tree_comparison (code)
1678 enum tree_code code;
1698 /* Return nonzero if two operands are necessarily equal.
1699 If ONLY_CONST is non-zero, only return non-zero for constants.
1700 This function tests whether the operands are indistinguishable;
1701 it does not test whether they are equal using C's == operation.
1702 The distinction is important for IEEE floating point, because
1703 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
1704 (2) two NaNs may be indistinguishable, but NaN!=NaN. */
1707 operand_equal_p (arg0, arg1, only_const)
1711 /* If both types don't have the same signedness, then we can't consider
1712 them equal. We must check this before the STRIP_NOPS calls
1713 because they may change the signedness of the arguments. */
1714 if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
1720 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
1721 We don't care about side effects in that case because the SAVE_EXPR
1722 takes care of that for us. */
1723 if (TREE_CODE (arg0) == SAVE_EXPR && arg0 == arg1)
1724 return ! only_const;
1726 if (TREE_SIDE_EFFECTS (arg0) || TREE_SIDE_EFFECTS (arg1))
1729 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1730 && TREE_CODE (arg0) == ADDR_EXPR
1731 && TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0))
1734 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1735 && TREE_CODE (arg0) == INTEGER_CST
1736 && TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
1737 && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1))
1740 /* Detect when real constants are equal. */
1741 if (TREE_CODE (arg0) == TREE_CODE (arg1)
1742 && TREE_CODE (arg0) == REAL_CST)
1743 return !bcmp (&TREE_REAL_CST (arg0), &TREE_REAL_CST (arg1),
1744 sizeof (REAL_VALUE_TYPE));
1752 if (TREE_CODE (arg0) != TREE_CODE (arg1))
1754 /* This is needed for conversions and for COMPONENT_REF.
1755 Might as well play it safe and always test this. */
1756 if (TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
1759 switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
1762 /* Two conversions are equal only if signedness and modes match. */
1763 if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
1764 && (TREE_UNSIGNED (TREE_TYPE (arg0))
1765 != TREE_UNSIGNED (TREE_TYPE (arg1))))
1768 return operand_equal_p (TREE_OPERAND (arg0, 0),
1769 TREE_OPERAND (arg1, 0), 0);
1773 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1774 TREE_OPERAND (arg1, 0), 0)
1775 && operand_equal_p (TREE_OPERAND (arg0, 1),
1776 TREE_OPERAND (arg1, 1), 0));
1779 switch (TREE_CODE (arg0))
1782 return operand_equal_p (TREE_OPERAND (arg0, 0),
1783 TREE_OPERAND (arg1, 0), 0);
1787 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1788 TREE_OPERAND (arg1, 0), 0)
1789 && operand_equal_p (TREE_OPERAND (arg0, 1),
1790 TREE_OPERAND (arg1, 1), 0));
1793 return (operand_equal_p (TREE_OPERAND (arg0, 0),
1794 TREE_OPERAND (arg1, 0), 0)
1795 && operand_equal_p (TREE_OPERAND (arg0, 1),
1796 TREE_OPERAND (arg1, 1), 0)
1797 && operand_equal_p (TREE_OPERAND (arg0, 2),
1798 TREE_OPERAND (arg1, 2), 0));
1806 /* Similar to operand_equal_p, but see if ARG0 might have been made by
1807 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
1809 When in doubt, return 0. */
1812 operand_equal_for_comparison_p (arg0, arg1, other)
1816 int unsignedp1, unsignedpo;
1817 tree primarg1, primother;
1820 if (operand_equal_p (arg0, arg1, 0))
1823 if (TREE_CODE (TREE_TYPE (arg0)) != INTEGER_TYPE)
1826 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
1827 actual comparison operand, ARG0.
1829 First throw away any conversions to wider types
1830 already present in the operands. */
1832 primarg1 = get_narrower (arg1, &unsignedp1);
1833 primother = get_narrower (other, &unsignedpo);
1835 correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
1836 if (unsignedp1 == unsignedpo
1837 && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
1838 && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
1840 tree type = TREE_TYPE (arg0);
1842 /* Make sure shorter operand is extended the right way
1843 to match the longer operand. */
1844 primarg1 = convert (signed_or_unsigned_type (unsignedp1,
1845 TREE_TYPE (primarg1)),
1848 if (operand_equal_p (arg0, convert (type, primarg1), 0))
1855 /* See if ARG is an expression that is either a comparison or is performing
1856 arithmetic on comparisons. The comparisons must only be comparing
1857 two different values, which will be stored in *CVAL1 and *CVAL2; if
1858 they are non-zero it means that some operands have already been found.
1859 No variables may be used anywhere else in the expression except in the
1862 If this is true, return 1. Otherwise, return zero. */
1865 twoval_comparison_p (arg, cval1, cval2)
1867 tree *cval1, *cval2;
1869 enum tree_code code = TREE_CODE (arg);
1870 char class = TREE_CODE_CLASS (code);
1872 /* We can handle some of the 'e' cases here. */
1874 && (code == TRUTH_NOT_EXPR
1875 || (code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0)))
1877 else if (class == 'e'
1878 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
1879 || code == COMPOUND_EXPR))
1885 return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2);
1888 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
1889 && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2));
1895 if (code == COND_EXPR)
1896 return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
1897 && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2)
1898 && twoval_comparison_p (TREE_OPERAND (arg, 2),
1903 /* First see if we can handle the first operand, then the second. For
1904 the second operand, we know *CVAL1 can't be zero. It must be that
1905 one side of the comparison is each of the values; test for the
1906 case where this isn't true by failing if the two operands
1909 if (operand_equal_p (TREE_OPERAND (arg, 0),
1910 TREE_OPERAND (arg, 1), 0))
1914 *cval1 = TREE_OPERAND (arg, 0);
1915 else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
1917 else if (*cval2 == 0)
1918 *cval2 = TREE_OPERAND (arg, 0);
1919 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
1924 if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
1926 else if (*cval2 == 0)
1927 *cval2 = TREE_OPERAND (arg, 1);
1928 else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
1939 /* ARG is a tree that is known to contain just arithmetic operations and
1940 comparisons. Evaluate the operations in the tree substituting NEW0 for
1941 any occurrence of OLD0 as an operand of a comparison and likewise for
1945 eval_subst (arg, old0, new0, old1, new1)
1947 tree old0, new0, old1, new1;
1949 tree type = TREE_TYPE (arg);
1950 enum tree_code code = TREE_CODE (arg);
1951 char class = TREE_CODE_CLASS (code);
1953 /* We can handle some of the 'e' cases here. */
1954 if (class == 'e' && code == TRUTH_NOT_EXPR)
1956 else if (class == 'e'
1957 && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
1963 return fold (build1 (code, type,
1964 eval_subst (TREE_OPERAND (arg, 0),
1965 old0, new0, old1, new1)));
1968 return fold (build (code, type,
1969 eval_subst (TREE_OPERAND (arg, 0),
1970 old0, new0, old1, new1),
1971 eval_subst (TREE_OPERAND (arg, 1),
1972 old0, new0, old1, new1)));
1978 return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
1981 return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
1984 return fold (build (code, type,
1985 eval_subst (TREE_OPERAND (arg, 0),
1986 old0, new0, old1, new1),
1987 eval_subst (TREE_OPERAND (arg, 1),
1988 old0, new0, old1, new1),
1989 eval_subst (TREE_OPERAND (arg, 2),
1990 old0, new0, old1, new1)));
1995 tree arg0 = TREE_OPERAND (arg, 0);
1996 tree arg1 = TREE_OPERAND (arg, 1);
1998 /* We need to check both for exact equality and tree equality. The
1999 former will be true if the operand has a side-effect. In that
2000 case, we know the operand occurred exactly once. */
2002 if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
2004 else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
2007 if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
2009 else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
2012 return fold (build (code, type, arg0, arg1));
2019 /* Return a tree for the case when the result of an expression is RESULT
2020 converted to TYPE and OMITTED was previously an operand of the expression
2021 but is now not needed (e.g., we folded OMITTED * 0).
2023 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2024 the conversion of RESULT to TYPE. */
2027 omit_one_operand (type, result, omitted)
2028 tree type, result, omitted;
2030 tree t = convert (type, result);
2032 if (TREE_SIDE_EFFECTS (omitted))
2033 return build (COMPOUND_EXPR, type, omitted, t);
2035 return non_lvalue (t);
2038 /* Return a simplified tree node for the truth-negation of ARG. This
2039 never alters ARG itself. We assume that ARG is an operation that
2040 returns a truth value (0 or 1). */
2043 invert_truthvalue (arg)
2046 tree type = TREE_TYPE (arg);
2047 enum tree_code code = TREE_CODE (arg);
2049 /* If this is a comparison, we can simply invert it, except for
2050 floating-point non-equality comparisons, in which case we just
2051 enclose a TRUTH_NOT_EXPR around what we have. */
2053 if (TREE_CODE_CLASS (code) == '<')
2055 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 0))) == REAL_TYPE
2056 && code != NE_EXPR && code != EQ_EXPR)
2057 return build1 (TRUTH_NOT_EXPR, type, arg);
2059 return build (invert_tree_comparison (code), type,
2060 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2066 return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0
2067 && TREE_INT_CST_HIGH (arg) == 0, 0));
2069 case TRUTH_AND_EXPR:
2070 return build (TRUTH_OR_EXPR, type,
2071 invert_truthvalue (TREE_OPERAND (arg, 0)),
2072 invert_truthvalue (TREE_OPERAND (arg, 1)));
2075 return build (TRUTH_AND_EXPR, type,
2076 invert_truthvalue (TREE_OPERAND (arg, 0)),
2077 invert_truthvalue (TREE_OPERAND (arg, 1)));
2079 case TRUTH_XOR_EXPR:
2080 /* Here we can invert either operand. We invert the first operand
2081 unless the second operand is a TRUTH_NOT_EXPR in which case our
2082 result is the XOR of the first operand with the inside of the
2083 negation of the second operand. */
2085 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
2086 return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
2087 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
2089 return build (TRUTH_XOR_EXPR, type,
2090 invert_truthvalue (TREE_OPERAND (arg, 0)),
2091 TREE_OPERAND (arg, 1));
2093 case TRUTH_ANDIF_EXPR:
2094 return build (TRUTH_ORIF_EXPR, type,
2095 invert_truthvalue (TREE_OPERAND (arg, 0)),
2096 invert_truthvalue (TREE_OPERAND (arg, 1)));
2098 case TRUTH_ORIF_EXPR:
2099 return build (TRUTH_ANDIF_EXPR, type,
2100 invert_truthvalue (TREE_OPERAND (arg, 0)),
2101 invert_truthvalue (TREE_OPERAND (arg, 1)));
2103 case TRUTH_NOT_EXPR:
2104 return TREE_OPERAND (arg, 0);
2107 return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
2108 invert_truthvalue (TREE_OPERAND (arg, 1)),
2109 invert_truthvalue (TREE_OPERAND (arg, 2)));
2112 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
2113 invert_truthvalue (TREE_OPERAND (arg, 1)));
2115 case NON_LVALUE_EXPR:
2116 return invert_truthvalue (TREE_OPERAND (arg, 0));
2121 return build1 (TREE_CODE (arg), type,
2122 invert_truthvalue (TREE_OPERAND (arg, 0)));
2125 if (! integer_onep (TREE_OPERAND (arg, 1)))
2127 return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
2133 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
2134 operands are another bit-wise operation with a common input. If so,
2135 distribute the bit operations to save an operation and possibly two if
2136 constants are involved. For example, convert
2137 (A | B) & (A | C) into A | (B & C)
2138 Further simplification will occur if B and C are constants.
2140 If this optimization cannot be done, 0 will be returned. */
2143 distribute_bit_expr (code, type, arg0, arg1)
2144 enum tree_code code;
2151 if (TREE_CODE (arg0) != TREE_CODE (arg1)
2152 || TREE_CODE (arg0) == code
2153 || (TREE_CODE (arg0) != BIT_AND_EXPR
2154 && TREE_CODE (arg0) != BIT_IOR_EXPR))
2157 if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
2159 common = TREE_OPERAND (arg0, 0);
2160 left = TREE_OPERAND (arg0, 1);
2161 right = TREE_OPERAND (arg1, 1);
2163 else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
2165 common = TREE_OPERAND (arg0, 0);
2166 left = TREE_OPERAND (arg0, 1);
2167 right = TREE_OPERAND (arg1, 0);
2169 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
2171 common = TREE_OPERAND (arg0, 1);
2172 left = TREE_OPERAND (arg0, 0);
2173 right = TREE_OPERAND (arg1, 1);
2175 else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
2177 common = TREE_OPERAND (arg0, 1);
2178 left = TREE_OPERAND (arg0, 0);
2179 right = TREE_OPERAND (arg1, 0);
2184 return fold (build (TREE_CODE (arg0), type, common,
2185 fold (build (code, type, left, right))));
2188 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
2189 starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
2192 make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
2195 int bitsize, bitpos;
2198 tree result = build (BIT_FIELD_REF, type, inner,
2199 size_int (bitsize), size_int (bitpos));
2201 TREE_UNSIGNED (result) = unsignedp;
2206 /* Optimize a bit-field compare.
2208 There are two cases: First is a compare against a constant and the
2209 second is a comparison of two items where the fields are at the same
2210 bit position relative to the start of a chunk (byte, halfword, word)
2211 large enough to contain it. In these cases we can avoid the shift
2212 implicit in bitfield extractions.
2214 For constants, we emit a compare of the shifted constant with the
2215 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
2216 compared. For two fields at the same position, we do the ANDs with the
2217 similar mask and compare the result of the ANDs.
2219 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
2220 COMPARE_TYPE is the type of the comparison, and LHS and RHS
2221 are the left and right operands of the comparison, respectively.
2223 If the optimization described above can be done, we return the resulting
2224 tree. Otherwise we return zero. */
2227 optimize_bit_field_compare (code, compare_type, lhs, rhs)
2228 enum tree_code code;
2232 int lbitpos, lbitsize, rbitpos, rbitsize;
2233 int lnbitpos, lnbitsize, rnbitpos, rnbitsize;
2234 tree type = TREE_TYPE (lhs);
2235 tree signed_type, unsigned_type;
2236 int const_p = TREE_CODE (rhs) == INTEGER_CST;
2237 enum machine_mode lmode, rmode, lnmode, rnmode;
2238 int lunsignedp, runsignedp;
2239 int lvolatilep = 0, rvolatilep = 0;
2240 tree linner, rinner;
2244 /* Get all the information about the extractions being done. If the bit size
2245 if the same as the size of the underlying object, we aren't doing an
2246 extraction at all and so can do nothing. */
2247 linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
2248 &lunsignedp, &lvolatilep);
2249 if (lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
2255 /* If this is not a constant, we can only do something if bit positions,
2256 sizes, and signedness are the same. */
2257 rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset,
2258 &rmode, &runsignedp, &rvolatilep);
2260 if (lbitpos != rbitpos || lbitsize != rbitsize
2261 || lunsignedp != runsignedp || offset != 0)
2265 /* See if we can find a mode to refer to this field. We should be able to,
2266 but fail if we can't. */
2267 lnmode = get_best_mode (lbitsize, lbitpos,
2268 TYPE_ALIGN (TREE_TYPE (linner)), word_mode,
2270 if (lnmode == VOIDmode)
2273 /* Set signed and unsigned types of the precision of this mode for the
2275 signed_type = type_for_mode (lnmode, 0);
2276 unsigned_type = type_for_mode (lnmode, 1);
2280 rnmode = get_best_mode (rbitsize, rbitpos,
2281 TYPE_ALIGN (TREE_TYPE (rinner)), word_mode,
2283 if (rnmode == VOIDmode)
2287 /* Compute the bit position and size for the new reference and our offset
2288 within it. If the new reference is the same size as the original, we
2289 won't optimize anything, so return zero. */
2290 lnbitsize = GET_MODE_BITSIZE (lnmode);
2291 lnbitpos = lbitpos & ~ (lnbitsize - 1);
2292 lbitpos -= lnbitpos;
2293 if (lnbitsize == lbitsize)
2298 rnbitsize = GET_MODE_BITSIZE (rnmode);
2299 rnbitpos = rbitpos & ~ (rnbitsize - 1);
2300 rbitpos -= rnbitpos;
2301 if (rnbitsize == rbitsize)
2305 #if BYTES_BIG_ENDIAN
2306 lbitpos = lnbitsize - lbitsize - lbitpos;
2309 /* Make the mask to be used against the extracted field. */
2310 mask = build_int_2 (~0, ~0);
2311 TREE_TYPE (mask) = unsigned_type;
2312 force_fit_type (mask);
2313 mask = convert (unsigned_type, mask);
2314 mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0);
2315 mask = const_binop (RSHIFT_EXPR, mask,
2316 size_int (lnbitsize - lbitsize - lbitpos), 0);
2319 /* If not comparing with constant, just rework the comparison
2321 return build (code, compare_type,
2322 build (BIT_AND_EXPR, unsigned_type,
2323 make_bit_field_ref (linner, unsigned_type,
2324 lnbitsize, lnbitpos, 1),
2326 build (BIT_AND_EXPR, unsigned_type,
2327 make_bit_field_ref (rinner, unsigned_type,
2328 rnbitsize, rnbitpos, 1),
2331 /* Otherwise, we are handling the constant case. See if the constant is too
2332 big for the field. Warn and return a tree of for 0 (false) if so. We do
2333 this not only for its own sake, but to avoid having to test for this
2334 error case below. If we didn't, we might generate wrong code.
2336 For unsigned fields, the constant shifted right by the field length should
2337 be all zero. For signed fields, the high-order bits should agree with
2342 if (! integer_zerop (const_binop (RSHIFT_EXPR,
2343 convert (unsigned_type, rhs),
2344 size_int (lbitsize), 0)))
2346 warning ("comparison is always %s due to width of bitfield",
2347 code == NE_EXPR ? "one" : "zero");
2348 return convert (compare_type,
2350 ? integer_one_node : integer_zero_node));
2355 tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
2356 size_int (lbitsize - 1), 0);
2357 if (! integer_zerop (tem) && ! integer_all_onesp (tem))
2359 warning ("comparison is always %s due to width of bitfield",
2360 code == NE_EXPR ? "one" : "zero");
2361 return convert (compare_type,
2363 ? integer_one_node : integer_zero_node));
2367 /* Single-bit compares should always be against zero. */
2368 if (lbitsize == 1 && ! integer_zerop (rhs))
2370 code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
2371 rhs = convert (type, integer_zero_node);
2374 /* Make a new bitfield reference, shift the constant over the
2375 appropriate number of bits and mask it with the computed mask
2376 (in case this was a signed field). If we changed it, make a new one. */
2377 lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1);
2379 rhs = fold (const_binop (BIT_AND_EXPR,
2380 const_binop (LSHIFT_EXPR,
2381 convert (unsigned_type, rhs),
2382 size_int (lbitpos)),
2385 return build (code, compare_type,
2386 build (BIT_AND_EXPR, unsigned_type, lhs, mask),
2390 /* Subroutine for fold_truthop: decode a field reference.
2392 If EXP is a comparison reference, we return the innermost reference.
2394 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
2395 set to the starting bit number.
2397 If the innermost field can be completely contained in a mode-sized
2398 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
2400 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
2401 otherwise it is not changed.
2403 *PUNSIGNEDP is set to the signedness of the field.
2405 *PMASK is set to the mask used. This is either contained in a
2406 BIT_AND_EXPR or derived from the width of the field.
2408 Return 0 if this is not a component reference or is one that we can't
2409 do anything with. */
2412 decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
2415 int *pbitsize, *pbitpos;
2416 enum machine_mode *pmode;
2417 int *punsignedp, *pvolatilep;
2426 if (TREE_CODE (exp) == BIT_AND_EXPR)
2428 mask = TREE_OPERAND (exp, 1);
2429 exp = TREE_OPERAND (exp, 0);
2430 STRIP_NOPS (exp); STRIP_NOPS (mask);
2431 if (TREE_CODE (mask) != INTEGER_CST)
2435 if (TREE_CODE (exp) != COMPONENT_REF && TREE_CODE (exp) != ARRAY_REF
2436 && TREE_CODE (exp) != BIT_FIELD_REF)
2439 inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
2440 punsignedp, pvolatilep);
2441 if (*pbitsize < 0 || offset != 0)
2446 tree unsigned_type = type_for_size (*pbitsize, 1);
2447 int precision = TYPE_PRECISION (unsigned_type);
2449 mask = build_int_2 (~0, ~0);
2450 TREE_TYPE (mask) = unsigned_type;
2451 force_fit_type (mask, 0);
2452 mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2453 mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
2460 /* Return non-zero if MASK represents a mask of SIZE ones in the low-order
2464 all_ones_mask_p (mask, size)
2468 tree type = TREE_TYPE (mask);
2469 int precision = TYPE_PRECISION (type);
2472 tmask = build_int_2 (~0, ~0);
2473 TREE_TYPE (tmask) = signed_type (type);
2474 force_fit_type (tmask);
2476 operand_equal_p (mask,
2477 const_binop (RSHIFT_EXPR,
2478 const_binop (LSHIFT_EXPR, tmask,
2479 size_int (precision - size), 0),
2480 size_int (precision - size), 0),
2484 /* Subroutine for fold_truthop: determine if an operand is simple enough
2485 to be evaluated unconditionally. */
2491 simple_operand_p (exp)
2494 /* Strip any conversions that don't change the machine mode. */
2495 while ((TREE_CODE (exp) == NOP_EXPR
2496 || TREE_CODE (exp) == CONVERT_EXPR)
2497 && (TYPE_MODE (TREE_TYPE (exp))
2498 == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
2499 exp = TREE_OPERAND (exp, 0);
2501 return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
2502 || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
2503 && ! TREE_ADDRESSABLE (exp)
2504 && ! TREE_THIS_VOLATILE (exp)
2505 && ! DECL_NONLOCAL (exp)
2506 /* Don't regard global variables as simple. They may be
2507 allocated in ways unknown to the compiler (shared memory,
2508 #pragma weak, etc). */
2509 && ! TREE_PUBLIC (exp)
2510 && ! DECL_EXTERNAL (exp)
2511 /* Loading a static variable is unduly expensive, but global
2512 registers aren't expensive. */
2513 && (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
2516 /* Subroutine for fold_truthop: try to optimize a range test.
2518 For example, "i >= 2 && i =< 9" can be done as "(unsigned) (i - 2) <= 7".
2520 JCODE is the logical combination of the two terms. It is TRUTH_AND_EXPR
2521 (representing TRUTH_ANDIF_EXPR and TRUTH_AND_EXPR) or TRUTH_OR_EXPR
2522 (representing TRUTH_ORIF_EXPR and TRUTH_OR_EXPR). TYPE is the type of
2525 VAR is the value being tested. LO_CODE and HI_CODE are the comparison
2526 operators comparing VAR to LO_CST and HI_CST. LO_CST is known to be no
2527 larger than HI_CST (they may be equal).
2529 We return the simplified tree or 0 if no optimization is possible. */
2532 range_test (jcode, type, lo_code, hi_code, var, lo_cst, hi_cst)
2533 enum tree_code jcode, lo_code, hi_code;
2534 tree type, var, lo_cst, hi_cst;
2537 enum tree_code rcode;
2539 /* See if this is a range test and normalize the constant terms. */
2541 if (jcode == TRUTH_AND_EXPR)
2546 /* See if we have VAR != CST && VAR != CST+1. */
2547 if (! (hi_code == NE_EXPR
2548 && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
2549 && tree_int_cst_equal (integer_one_node,
2550 const_binop (MINUS_EXPR,
2551 hi_cst, lo_cst, 0))))
2559 if (hi_code == LT_EXPR)
2560 hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
2561 else if (hi_code != LE_EXPR)
2564 if (lo_code == GT_EXPR)
2565 lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
2567 /* We now have VAR >= LO_CST && VAR <= HI_CST. */
2580 /* See if we have VAR == CST || VAR == CST+1. */
2581 if (! (hi_code == EQ_EXPR
2582 && TREE_INT_CST_LOW (hi_cst) - TREE_INT_CST_LOW (lo_cst) == 1
2583 && tree_int_cst_equal (integer_one_node,
2584 const_binop (MINUS_EXPR,
2585 hi_cst, lo_cst, 0))))
2593 if (hi_code == GE_EXPR)
2594 hi_cst = const_binop (MINUS_EXPR, hi_cst, integer_one_node, 0);
2595 else if (hi_code != GT_EXPR)
2598 if (lo_code == LE_EXPR)
2599 lo_cst = const_binop (PLUS_EXPR, lo_cst, integer_one_node, 0);
2601 /* We now have VAR < LO_CST || VAR > HI_CST. */
2610 /* When normalizing, it is possible to both increment the smaller constant
2611 and decrement the larger constant. See if they are still ordered. */
2612 if (tree_int_cst_lt (hi_cst, lo_cst))
2615 /* Fail if VAR isn't an integer. */
2616 utype = TREE_TYPE (var);
2617 if (TREE_CODE (utype) != INTEGER_TYPE
2618 && TREE_CODE (utype) != ENUMERAL_TYPE)
2621 /* The range test is invalid if subtracting the two constants results
2622 in overflow. This can happen in traditional mode. */
2623 if (! int_fits_type_p (hi_cst, TREE_TYPE (var))
2624 || ! int_fits_type_p (lo_cst, TREE_TYPE (var)))
2627 if (! TREE_UNSIGNED (utype))
2629 utype = unsigned_type (utype);
2630 var = convert (utype, var);
2631 lo_cst = convert (utype, lo_cst);
2632 hi_cst = convert (utype, hi_cst);
2635 return fold (convert (type,
2636 build (rcode, utype,
2637 build (MINUS_EXPR, utype, var, lo_cst),
2638 const_binop (MINUS_EXPR, hi_cst, lo_cst, 0))));
2641 /* Find ways of folding logical expressions of LHS and RHS:
2642 Try to merge two comparisons to the same innermost item.
2643 Look for range tests like "ch >= '0' && ch <= '9'".
2644 Look for combinations of simple terms on machines with expensive branches
2645 and evaluate the RHS unconditionally.
2647 For example, if we have p->a == 2 && p->b == 4 and we can make an
2648 object large enough to span both A and B, we can do this with a comparison
2649 against the object ANDed with the a mask.
2651 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
2652 operations to do this with one comparison.
2654 We check for both normal comparisons and the BIT_AND_EXPRs made this by
2655 function and the one above.
2657 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
2658 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
2660 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
2663 We return the simplified tree or 0 if no optimization is possible. */
2666 fold_truthop (code, truth_type, lhs, rhs)
2667 enum tree_code code;
2668 tree truth_type, lhs, rhs;
2670 /* If this is the "or" of two comparisons, we can do something if we
2671 the comparisons are NE_EXPR. If this is the "and", we can do something
2672 if the comparisons are EQ_EXPR. I.e.,
2673 (a->b == 2 && a->c == 4) can become (a->new == NEW).
2675 WANTED_CODE is this operation code. For single bit fields, we can
2676 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
2677 comparison for one-bit fields. */
2679 enum tree_code wanted_code;
2680 enum tree_code lcode, rcode;
2681 tree ll_arg, lr_arg, rl_arg, rr_arg;
2682 tree ll_inner, lr_inner, rl_inner, rr_inner;
2683 int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
2684 int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
2685 int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
2686 int lnbitsize, lnbitpos, rnbitsize, rnbitpos;
2687 int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
2688 enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
2689 enum machine_mode lnmode, rnmode;
2690 tree ll_mask, lr_mask, rl_mask, rr_mask;
2691 tree l_const, r_const;
2693 int first_bit, end_bit;
2696 /* Start by getting the comparison codes and seeing if this looks like
2697 a range test. Fail if anything is volatile. */
2699 if (TREE_SIDE_EFFECTS (lhs)
2700 || TREE_SIDE_EFFECTS (rhs))
2703 lcode = TREE_CODE (lhs);
2704 rcode = TREE_CODE (rhs);
2706 if (TREE_CODE_CLASS (lcode) != '<'
2707 || TREE_CODE_CLASS (rcode) != '<')
2710 code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
2711 ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
2713 ll_arg = TREE_OPERAND (lhs, 0);
2714 lr_arg = TREE_OPERAND (lhs, 1);
2715 rl_arg = TREE_OPERAND (rhs, 0);
2716 rr_arg = TREE_OPERAND (rhs, 1);
2718 if (TREE_CODE (lr_arg) == INTEGER_CST
2719 && TREE_CODE (rr_arg) == INTEGER_CST
2720 && operand_equal_p (ll_arg, rl_arg, 0))
2722 if (tree_int_cst_lt (lr_arg, rr_arg))
2723 result = range_test (code, truth_type, lcode, rcode,
2724 ll_arg, lr_arg, rr_arg);
2726 result = range_test (code, truth_type, rcode, lcode,
2727 ll_arg, rr_arg, lr_arg);
2729 /* If this isn't a range test, it also isn't a comparison that
2730 can be merged. However, it wins to evaluate the RHS unconditionally
2731 on machines with expensive branches. */
2733 if (result == 0 && BRANCH_COST >= 2)
2735 if (TREE_CODE (ll_arg) != VAR_DECL
2736 && TREE_CODE (ll_arg) != PARM_DECL)
2738 /* Avoid evaluating the variable part twice. */
2739 ll_arg = save_expr (ll_arg);
2740 lhs = build (lcode, TREE_TYPE (lhs), ll_arg, lr_arg);
2741 rhs = build (rcode, TREE_TYPE (rhs), ll_arg, rr_arg);
2743 return build (code, truth_type, lhs, rhs);
2748 /* If the RHS can be evaluated unconditionally and its operands are
2749 simple, it wins to evaluate the RHS unconditionally on machines
2750 with expensive branches. In this case, this isn't a comparison
2751 that can be merged. */
2753 /* @@ I'm not sure it wins on the m88110 to do this if the comparisons
2754 are with zero (tmw). */
2756 if (BRANCH_COST >= 2
2757 && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
2758 && simple_operand_p (rl_arg)
2759 && simple_operand_p (rr_arg))
2760 return build (code, truth_type, lhs, rhs);
2762 /* See if the comparisons can be merged. Then get all the parameters for
2765 if ((lcode != EQ_EXPR && lcode != NE_EXPR)
2766 || (rcode != EQ_EXPR && rcode != NE_EXPR))
2770 ll_inner = decode_field_reference (ll_arg,
2771 &ll_bitsize, &ll_bitpos, &ll_mode,
2772 &ll_unsignedp, &volatilep, &ll_mask);
2773 lr_inner = decode_field_reference (lr_arg,
2774 &lr_bitsize, &lr_bitpos, &lr_mode,
2775 &lr_unsignedp, &volatilep, &lr_mask);
2776 rl_inner = decode_field_reference (rl_arg,
2777 &rl_bitsize, &rl_bitpos, &rl_mode,
2778 &rl_unsignedp, &volatilep, &rl_mask);
2779 rr_inner = decode_field_reference (rr_arg,
2780 &rr_bitsize, &rr_bitpos, &rr_mode,
2781 &rr_unsignedp, &volatilep, &rr_mask);
2783 /* It must be true that the inner operation on the lhs of each
2784 comparison must be the same if we are to be able to do anything.
2785 Then see if we have constants. If not, the same must be true for
2787 if (volatilep || ll_inner == 0 || rl_inner == 0
2788 || ! operand_equal_p (ll_inner, rl_inner, 0))
2791 if (TREE_CODE (lr_arg) == INTEGER_CST
2792 && TREE_CODE (rr_arg) == INTEGER_CST)
2793 l_const = lr_arg, r_const = rr_arg;
2794 else if (lr_inner == 0 || rr_inner == 0
2795 || ! operand_equal_p (lr_inner, rr_inner, 0))
2798 l_const = r_const = 0;
2800 /* If either comparison code is not correct for our logical operation,
2801 fail. However, we can convert a one-bit comparison against zero into
2802 the opposite comparison against that bit being set in the field. */
2804 wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
2805 if (lcode != wanted_code)
2807 if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
2813 if (rcode != wanted_code)
2815 if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
2821 /* See if we can find a mode that contains both fields being compared on
2822 the left. If we can't, fail. Otherwise, update all constants and masks
2823 to be relative to a field of that size. */
2824 first_bit = MIN (ll_bitpos, rl_bitpos);
2825 end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
2826 lnmode = get_best_mode (end_bit - first_bit, first_bit,
2827 TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
2829 if (lnmode == VOIDmode)
2832 lnbitsize = GET_MODE_BITSIZE (lnmode);
2833 lnbitpos = first_bit & ~ (lnbitsize - 1);
2834 type = type_for_size (lnbitsize, 1);
2835 xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
2837 #if BYTES_BIG_ENDIAN
2838 xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
2839 xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
2842 ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask),
2843 size_int (xll_bitpos), 0);
2844 rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask),
2845 size_int (xrl_bitpos), 0);
2847 /* Make sure the constants are interpreted as unsigned, so we
2848 don't have sign bits outside the range of their type. */
2852 l_const = convert (unsigned_type (TREE_TYPE (l_const)), l_const);
2853 l_const = const_binop (LSHIFT_EXPR, convert (type, l_const),
2854 size_int (xll_bitpos), 0);
2858 r_const = convert (unsigned_type (TREE_TYPE (r_const)), r_const);
2859 r_const = const_binop (LSHIFT_EXPR, convert (type, r_const),
2860 size_int (xrl_bitpos), 0);
2863 /* If the right sides are not constant, do the same for it. Also,
2864 disallow this optimization if a size or signedness mismatch occurs
2865 between the left and right sides. */
2868 if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
2869 || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
2870 /* Make sure the two fields on the right
2871 correspond to the left without being swapped. */
2872 || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
2875 first_bit = MIN (lr_bitpos, rr_bitpos);
2876 end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
2877 rnmode = get_best_mode (end_bit - first_bit, first_bit,
2878 TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
2880 if (rnmode == VOIDmode)
2883 rnbitsize = GET_MODE_BITSIZE (rnmode);
2884 rnbitpos = first_bit & ~ (rnbitsize - 1);
2885 xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
2887 #if BYTES_BIG_ENDIAN
2888 xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
2889 xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
2892 lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask),
2893 size_int (xlr_bitpos), 0);
2894 rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask),
2895 size_int (xrr_bitpos), 0);
2897 /* Make a mask that corresponds to both fields being compared.
2898 Do this for both items being compared. If the masks agree,
2899 we can do this by masking both and comparing the masked
2901 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
2902 lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
2903 if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize)
2905 lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
2906 ll_unsignedp || rl_unsignedp);
2907 rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos,
2908 lr_unsignedp || rr_unsignedp);
2909 if (! all_ones_mask_p (ll_mask, lnbitsize))
2911 lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
2912 rhs = build (BIT_AND_EXPR, type, rhs, ll_mask);
2914 return build (wanted_code, truth_type, lhs, rhs);
2917 /* There is still another way we can do something: If both pairs of
2918 fields being compared are adjacent, we may be able to make a wider
2919 field containing them both. */
2920 if ((ll_bitsize + ll_bitpos == rl_bitpos
2921 && lr_bitsize + lr_bitpos == rr_bitpos)
2922 || (ll_bitpos == rl_bitpos + rl_bitsize
2923 && lr_bitpos == rr_bitpos + rr_bitsize))
2924 return build (wanted_code, truth_type,
2925 make_bit_field_ref (ll_inner, type,
2926 ll_bitsize + rl_bitsize,
2927 MIN (ll_bitpos, rl_bitpos),
2929 make_bit_field_ref (lr_inner, type,
2930 lr_bitsize + rr_bitsize,
2931 MIN (lr_bitpos, rr_bitpos),
2937 /* Handle the case of comparisons with constants. If there is something in
2938 common between the masks, those bits of the constants must be the same.
2939 If not, the condition is always false. Test for this to avoid generating
2940 incorrect code below. */
2941 result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
2942 if (! integer_zerop (result)
2943 && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
2944 const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
2946 if (wanted_code == NE_EXPR)
2948 warning ("`or' of unmatched not-equal tests is always 1");
2949 return convert (truth_type, integer_one_node);
2953 warning ("`and' of mutually exclusive equal-tests is always zero");
2954 return convert (truth_type, integer_zero_node);
2958 /* Construct the expression we will return. First get the component
2959 reference we will make. Unless the mask is all ones the width of
2960 that field, perform the mask operation. Then compare with the
2962 result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos,
2963 ll_unsignedp || rl_unsignedp);
2965 ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
2966 if (! all_ones_mask_p (ll_mask, lnbitsize))
2967 result = build (BIT_AND_EXPR, type, result, ll_mask);
2969 return build (wanted_code, truth_type, result,
2970 const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
2973 /* Perform constant folding and related simplification of EXPR.
2974 The related simplifications include x*1 => x, x*0 => 0, etc.,
2975 and application of the associative law.
2976 NOP_EXPR conversions may be removed freely (as long as we
2977 are careful not to change the C type of the overall expression)
2978 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
2979 but we can constant-fold them if they have constant operands. */
2985 register tree t = expr;
2986 tree t1 = NULL_TREE;
2988 tree type = TREE_TYPE (expr);
2989 register tree arg0, arg1;
2990 register enum tree_code code = TREE_CODE (t);
2994 /* WINS will be nonzero when the switch is done
2995 if all operands are constant. */
2999 /* Return right away if already constant. */
3000 if (TREE_CONSTANT (t))
3002 if (code == CONST_DECL)
3003 return DECL_INITIAL (t);
3007 kind = TREE_CODE_CLASS (code);
3008 if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
3012 /* Special case for conversion ops that can have fixed point args. */
3013 arg0 = TREE_OPERAND (t, 0);
3015 /* Don't use STRIP_NOPS, because signedness of argument type matters. */
3017 STRIP_TYPE_NOPS (arg0);
3019 if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
3020 subop = TREE_REALPART (arg0);
3024 if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
3025 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3026 && TREE_CODE (subop) != REAL_CST
3027 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3029 /* Note that TREE_CONSTANT isn't enough:
3030 static var addresses are constant but we can't
3031 do arithmetic on them. */
3034 else if (kind == 'e' || kind == '<'
3035 || kind == '1' || kind == '2' || kind == 'r')
3037 register int len = tree_code_length[(int) code];
3039 for (i = 0; i < len; i++)
3041 tree op = TREE_OPERAND (t, i);
3045 continue; /* Valid for CALL_EXPR, at least. */
3047 /* Strip any conversions that don't change the mode. */
3050 if (TREE_CODE (op) == COMPLEX_CST)
3051 subop = TREE_REALPART (op);
3055 if (TREE_CODE (subop) != INTEGER_CST
3056 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3057 && TREE_CODE (subop) != REAL_CST
3058 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3060 /* Note that TREE_CONSTANT isn't enough:
3061 static var addresses are constant but we can't
3062 do arithmetic on them. */
3072 /* If this is a commutative operation, and ARG0 is a constant, move it
3073 to ARG1 to reduce the number of tests below. */
3074 if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
3075 || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
3076 || code == BIT_AND_EXPR)
3077 && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
3079 tem = arg0; arg0 = arg1; arg1 = tem;
3081 tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
3082 TREE_OPERAND (t, 1) = tem;
3085 /* Now WINS is set as described above,
3086 ARG0 is the first operand of EXPR,
3087 and ARG1 is the second operand (if it has more than one operand).
3089 First check for cases where an arithmetic operation is applied to a
3090 compound, conditional, or comparison operation. Push the arithmetic
3091 operation inside the compound or conditional to see if any folding
3092 can then be done. Convert comparison to conditional for this purpose.
3093 The also optimizes non-constant cases that used to be done in
3095 if (TREE_CODE_CLASS (code) == '1')
3097 if (TREE_CODE (arg0) == COMPOUND_EXPR)
3098 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3099 fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
3100 else if (TREE_CODE (arg0) == COND_EXPR)
3102 t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
3103 fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
3104 fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
3106 /* If this was a conversion, and all we did was to move into
3107 inside the COND_EXPR, bring it back out. Then return so we
3108 don't get into an infinite recursion loop taking the conversion
3109 out and then back in. */
3111 if ((code == NOP_EXPR || code == CONVERT_EXPR
3112 || code == NON_LVALUE_EXPR)
3113 && TREE_CODE (t) == COND_EXPR
3114 && TREE_CODE (TREE_OPERAND (t, 1)) == code
3115 && TREE_CODE (TREE_OPERAND (t, 2)) == code
3116 && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
3117 == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0))))
3118 t = build1 (code, type,
3120 TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)),
3121 TREE_OPERAND (t, 0),
3122 TREE_OPERAND (TREE_OPERAND (t, 1), 0),
3123 TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
3126 else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3127 return fold (build (COND_EXPR, type, arg0,
3128 fold (build1 (code, type, integer_one_node)),
3129 fold (build1 (code, type, integer_zero_node))));
3131 else if (TREE_CODE_CLASS (code) == '2')
3133 if (TREE_CODE (arg1) == COMPOUND_EXPR)
3134 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3135 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3136 else if (TREE_CODE (arg1) == COND_EXPR
3137 || TREE_CODE_CLASS (TREE_CODE (arg1)) == '<')
3139 tree test, true_value, false_value;
3141 if (TREE_CODE (arg1) == COND_EXPR)
3143 test = TREE_OPERAND (arg1, 0);
3144 true_value = TREE_OPERAND (arg1, 1);
3145 false_value = TREE_OPERAND (arg1, 2);
3150 true_value = integer_one_node;
3151 false_value = integer_zero_node;
3154 if (TREE_CODE (arg0) != VAR_DECL && TREE_CODE (arg0) != PARM_DECL)
3155 arg0 = save_expr (arg0);
3156 test = fold (build (COND_EXPR, type, test,
3157 fold (build (code, type, arg0, true_value)),
3158 fold (build (code, type, arg0, false_value))));
3159 if (TREE_CODE (arg0) == SAVE_EXPR)
3160 return build (COMPOUND_EXPR, type,
3161 convert (void_type_node, arg0), test);
3163 return convert (type, test);
3166 else if (TREE_CODE (arg0) == COMPOUND_EXPR)
3167 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3168 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3169 else if (TREE_CODE (arg0) == COND_EXPR
3170 || TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
3172 tree test, true_value, false_value;
3174 if (TREE_CODE (arg0) == COND_EXPR)
3176 test = TREE_OPERAND (arg0, 0);
3177 true_value = TREE_OPERAND (arg0, 1);
3178 false_value = TREE_OPERAND (arg0, 2);
3183 true_value = integer_one_node;
3184 false_value = integer_zero_node;
3187 if (TREE_CODE (arg1) != VAR_DECL && TREE_CODE (arg1) != PARM_DECL)
3188 arg1 = save_expr (arg1);
3189 test = fold (build (COND_EXPR, type, test,
3190 fold (build (code, type, true_value, arg1)),
3191 fold (build (code, type, false_value, arg1))));
3192 if (TREE_CODE (arg1) == SAVE_EXPR)
3193 return build (COMPOUND_EXPR, type,
3194 convert (void_type_node, arg1), test);
3196 return convert (type, test);
3199 else if (TREE_CODE_CLASS (code) == '<'
3200 && TREE_CODE (arg0) == COMPOUND_EXPR)
3201 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
3202 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
3203 else if (TREE_CODE_CLASS (code) == '<'
3204 && TREE_CODE (arg1) == COMPOUND_EXPR)
3205 return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
3206 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
3218 return fold (DECL_INITIAL (t));
3223 case FIX_TRUNC_EXPR:
3224 /* Other kinds of FIX are not handled properly by fold_convert. */
3225 /* Two conversions in a row are not needed unless:
3226 - the intermediate type is narrower than both initial and final, or
3227 - the intermediate type and innermost type differ in signedness,
3228 and the outermost type is wider than the intermediate, or
3229 - the initial type is a pointer type and the precisions of the
3230 intermediate and final types differ, or
3231 - the final type is a pointer type and the precisions of the
3232 initial and intermediate types differ. */
3233 if ((TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
3234 || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
3235 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3236 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3238 TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3239 > TYPE_PRECISION (TREE_TYPE (t)))
3240 && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3242 && (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
3244 && (TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0)))
3245 != TREE_UNSIGNED (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3246 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3247 < TYPE_PRECISION (TREE_TYPE (t))))
3248 && ((TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (t, 0)))
3249 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3250 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))))
3252 (TREE_UNSIGNED (TREE_TYPE (t))
3253 && (TYPE_PRECISION (TREE_TYPE (t))
3254 > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))))))
3255 && ! ((TREE_CODE (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3257 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0)))
3258 != TYPE_PRECISION (TREE_TYPE (t))))
3259 && ! (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE
3260 && (TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)))
3261 != TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (t, 0))))))
3262 return convert (TREE_TYPE (t), TREE_OPERAND (TREE_OPERAND (t, 0), 0));
3264 if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
3265 && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
3266 /* Detect assigning a bitfield. */
3267 && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
3268 && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
3270 /* Don't leave an assignment inside a conversion
3271 unless assigning a bitfield. */
3272 tree prev = TREE_OPERAND (t, 0);
3273 TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
3274 /* First do the assignment, then return converted constant. */
3275 t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
3281 TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
3284 return fold_convert (t, arg0);
3286 #if 0 /* This loses on &"foo"[0]. */
3291 /* Fold an expression like: "foo"[2] */
3292 if (TREE_CODE (arg0) == STRING_CST
3293 && TREE_CODE (arg1) == INTEGER_CST
3294 && !TREE_INT_CST_HIGH (arg1)
3295 && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0))
3297 t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0);
3298 TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
3299 force_fit_type (t, 0);
3306 TREE_CONSTANT (t) = wins;
3312 if (TREE_CODE (arg0) == INTEGER_CST)
3314 HOST_WIDE_INT low, high;
3315 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
3316 TREE_INT_CST_HIGH (arg0),
3318 t = build_int_2 (low, high);
3319 TREE_TYPE (t) = type;
3320 TREE_CONSTANT_OVERFLOW (t)
3321 = (TREE_CONSTANT_OVERFLOW (arg0)
3322 | force_fit_type (t, overflow));
3324 else if (TREE_CODE (arg0) == REAL_CST)
3325 t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
3326 TREE_TYPE (t) = type;
3328 else if (TREE_CODE (arg0) == NEGATE_EXPR)
3329 return TREE_OPERAND (arg0, 0);
3331 /* Convert - (a - b) to (b - a) for non-floating-point. */
3332 else if (TREE_CODE (arg0) == MINUS_EXPR && TREE_CODE (type) != REAL_TYPE)
3333 return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
3334 TREE_OPERAND (arg0, 0));
3341 if (TREE_CODE (arg0) == INTEGER_CST)
3343 if (! TREE_UNSIGNED (type)
3344 && TREE_INT_CST_HIGH (arg0) < 0)
3346 HOST_WIDE_INT low, high;
3347 int overflow = neg_double (TREE_INT_CST_LOW (arg0),
3348 TREE_INT_CST_HIGH (arg0),
3350 t = build_int_2 (low, high);
3351 TREE_TYPE (t) = type;
3352 TREE_CONSTANT_OVERFLOW (t)
3353 = (TREE_CONSTANT_OVERFLOW (arg0)
3354 | force_fit_type (t, overflow));
3357 else if (TREE_CODE (arg0) == REAL_CST)
3359 if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
3360 t = build_real (type,
3361 REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
3363 TREE_TYPE (t) = type;
3365 else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
3366 return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
3372 if (TREE_CODE (arg0) == INTEGER_CST)
3373 t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
3374 ~ TREE_INT_CST_HIGH (arg0));
3375 TREE_TYPE (t) = type;
3376 force_fit_type (t, 0);
3377 TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
3379 else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
3380 return TREE_OPERAND (arg0, 0);
3384 /* A + (-B) -> A - B */
3385 if (TREE_CODE (arg1) == NEGATE_EXPR)
3386 return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
3387 else if (TREE_CODE (type) != REAL_TYPE)
3389 if (integer_zerop (arg1))
3390 return non_lvalue (convert (type, arg0));
3392 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
3393 with a constant, and the two constants have no bits in common,
3394 we should treat this as a BIT_IOR_EXPR since this may produce more
3396 if (TREE_CODE (arg0) == BIT_AND_EXPR
3397 && TREE_CODE (arg1) == BIT_AND_EXPR
3398 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
3399 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
3400 && integer_zerop (const_binop (BIT_AND_EXPR,
3401 TREE_OPERAND (arg0, 1),
3402 TREE_OPERAND (arg1, 1), 0)))
3404 code = BIT_IOR_EXPR;
3408 /* In IEEE floating point, x+0 may not equal x. */
3409 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3410 && real_zerop (arg1))
3411 return non_lvalue (convert (type, arg0));
3413 /* In most languages, can't associate operations on floats
3414 through parentheses. Rather than remember where the parentheses
3415 were, we don't associate floats at all. It shouldn't matter much. */
3416 if (TREE_CODE (type) == REAL_TYPE)
3418 /* The varsign == -1 cases happen only for addition and subtraction.
3419 It says that the arg that was split was really CON minus VAR.
3420 The rest of the code applies to all associative operations. */
3426 if (split_tree (arg0, code, &var, &con, &varsign))
3430 /* EXPR is (CON-VAR) +- ARG1. */
3431 /* If it is + and VAR==ARG1, return just CONST. */
3432 if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
3433 return convert (TREE_TYPE (t), con);
3435 /* If ARG0 is a constant, don't change things around;
3436 instead keep all the constant computations together. */
3438 if (TREE_CONSTANT (arg0))
3441 /* Otherwise return (CON +- ARG1) - VAR. */
3442 TREE_SET_CODE (t, MINUS_EXPR);
3443 TREE_OPERAND (t, 1) = var;
3445 = fold (build (code, TREE_TYPE (t), con, arg1));
3449 /* EXPR is (VAR+CON) +- ARG1. */
3450 /* If it is - and VAR==ARG1, return just CONST. */
3451 if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
3452 return convert (TREE_TYPE (t), con);
3454 /* If ARG0 is a constant, don't change things around;
3455 instead keep all the constant computations together. */
3457 if (TREE_CONSTANT (arg0))
3460 /* Otherwise return VAR +- (ARG1 +- CON). */
3461 TREE_OPERAND (t, 1) = tem
3462 = fold (build (code, TREE_TYPE (t), arg1, con));
3463 TREE_OPERAND (t, 0) = var;
3464 if (integer_zerop (tem)
3465 && (code == PLUS_EXPR || code == MINUS_EXPR))
3466 return convert (type, var);
3467 /* If we have x +/- (c - d) [c an explicit integer]
3468 change it to x -/+ (d - c) since if d is relocatable
3469 then the latter can be a single immediate insn
3470 and the former cannot. */
3471 if (TREE_CODE (tem) == MINUS_EXPR
3472 && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST)
3474 tree tem1 = TREE_OPERAND (tem, 1);
3475 TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0);
3476 TREE_OPERAND (tem, 0) = tem1;
3478 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
3484 if (split_tree (arg1, code, &var, &con, &varsign))
3486 /* EXPR is ARG0 +- (CON +- VAR). */
3487 if (TREE_CODE (t) == MINUS_EXPR
3488 && operand_equal_p (var, arg0, 0))
3490 /* If VAR and ARG0 cancel, return just CON or -CON. */
3491 if (code == PLUS_EXPR)
3492 return convert (TREE_TYPE (t), con);
3493 return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
3494 convert (TREE_TYPE (t), con)));
3496 if (TREE_CONSTANT (arg1))
3500 (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
3502 = fold (build (code, TREE_TYPE (t), arg0, con));
3503 TREE_OPERAND (t, 1) = var;
3504 if (integer_zerop (TREE_OPERAND (t, 0))
3505 && TREE_CODE (t) == PLUS_EXPR)
3506 return convert (TREE_TYPE (t), var);
3511 #if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
3512 if (TREE_CODE (arg1) == REAL_CST)
3514 #endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
3516 t1 = const_binop (code, arg0, arg1, 0);
3517 if (t1 != NULL_TREE)
3519 /* The return value should always have
3520 the same type as the original expression. */
3521 TREE_TYPE (t1) = TREE_TYPE (t);
3527 if (TREE_CODE (type) != REAL_TYPE)
3529 if (! wins && integer_zerop (arg0))
3530 return build1 (NEGATE_EXPR, type, arg1);
3531 if (integer_zerop (arg1))
3532 return non_lvalue (convert (type, arg0));
3534 /* Convert A - (-B) to A + B. */
3535 else if (TREE_CODE (arg1) == NEGATE_EXPR)
3536 return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
3537 else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
3539 /* Except with IEEE floating point, 0-x equals -x. */
3540 if (! wins && real_zerop (arg0))
3541 return build1 (NEGATE_EXPR, type, arg1);
3542 /* Except with IEEE floating point, x-0 equals x. */
3543 if (real_zerop (arg1))
3544 return non_lvalue (convert (type, arg0));
3546 /* Fold &x - &x. This can happen from &x.foo - &x.
3547 This is unsafe for certain floats even in non-IEEE formats.
3548 In IEEE, it is unsafe because it does wrong for NaNs.
3549 Also note that operand_equal_p is always false if an operand
3552 if (operand_equal_p (arg0, arg1,
3553 TREE_CODE (type) == REAL_TYPE))
3554 return convert (type, integer_zero_node);
3559 if (TREE_CODE (type) != REAL_TYPE)
3561 if (integer_zerop (arg1))
3562 return omit_one_operand (type, arg1, arg0);
3563 if (integer_onep (arg1))
3564 return non_lvalue (convert (type, arg0));
3566 /* (a * (1 << b)) is (a << b) */
3567 if (TREE_CODE (arg1) == LSHIFT_EXPR
3568 && integer_onep (TREE_OPERAND (arg1, 0)))
3569 return fold (build (LSHIFT_EXPR, type, arg0,
3570 TREE_OPERAND (arg1, 1)));
3571 if (TREE_CODE (arg0) == LSHIFT_EXPR
3572 && integer_onep (TREE_OPERAND (arg0, 0)))
3573 return fold (build (LSHIFT_EXPR, type, arg1,
3574 TREE_OPERAND (arg0, 1)));
3578 /* x*0 is 0, except for IEEE floating point. */
3579 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3580 && real_zerop (arg1))
3581 return omit_one_operand (type, arg1, arg0);
3582 /* In IEEE floating point, x*1 is not equivalent to x for snans.
3583 However, ANSI says we can drop signals,
3584 so we can do this anyway. */
3585 if (real_onep (arg1))
3586 return non_lvalue (convert (type, arg0));
3588 if (! wins && real_twop (arg1))
3590 tree arg = save_expr (arg0);
3591 return build (PLUS_EXPR, type, arg, arg);
3598 if (integer_all_onesp (arg1))
3599 return omit_one_operand (type, arg1, arg0);
3600 if (integer_zerop (arg1))
3601 return non_lvalue (convert (type, arg0));
3602 t1 = distribute_bit_expr (code, type, arg0, arg1);
3603 if (t1 != NULL_TREE)
3606 /* (a << C1) | (a >> C2) if A is unsigned and C1+C2 is the size of A
3607 is a rotate of A by C1 bits. */
3609 if ((TREE_CODE (arg0) == RSHIFT_EXPR
3610 || TREE_CODE (arg0) == LSHIFT_EXPR)
3611 && (TREE_CODE (arg1) == RSHIFT_EXPR
3612 || TREE_CODE (arg1) == LSHIFT_EXPR)
3613 && TREE_CODE (arg0) != TREE_CODE (arg1)
3614 && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0)
3615 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))
3616 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
3617 && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
3618 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
3619 && TREE_INT_CST_HIGH (TREE_OPERAND (arg1, 1)) == 0
3620 && ((TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))
3621 + TREE_INT_CST_LOW (TREE_OPERAND (arg1, 1)))
3622 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
3623 return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
3624 TREE_CODE (arg0) == LSHIFT_EXPR
3625 ? TREE_OPERAND (arg0, 1) : TREE_OPERAND (arg1, 1));
3630 if (integer_zerop (arg1))
3631 return non_lvalue (convert (type, arg0));
3632 if (integer_all_onesp (arg1))
3633 return fold (build1 (BIT_NOT_EXPR, type, arg0));
3638 if (integer_all_onesp (arg1))
3639 return non_lvalue (convert (type, arg0));
3640 if (integer_zerop (arg1))
3641 return omit_one_operand (type, arg1, arg0);
3642 t1 = distribute_bit_expr (code, type, arg0, arg1);
3643 if (t1 != NULL_TREE)
3645 /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
3646 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
3647 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
3649 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
3650 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
3651 && (~TREE_INT_CST_LOW (arg0)
3652 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
3653 return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
3655 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
3656 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
3658 int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
3659 if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
3660 && (~TREE_INT_CST_LOW (arg1)
3661 & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
3662 return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
3666 case BIT_ANDTC_EXPR:
3667 if (integer_all_onesp (arg0))
3668 return non_lvalue (convert (type, arg1));
3669 if (integer_zerop (arg0))
3670 return omit_one_operand (type, arg0, arg1);
3671 if (TREE_CODE (arg1) == INTEGER_CST)
3673 arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
3674 code = BIT_AND_EXPR;
3679 case TRUNC_DIV_EXPR:
3680 case ROUND_DIV_EXPR:
3681 case FLOOR_DIV_EXPR:
3683 case EXACT_DIV_EXPR:
3685 if (integer_onep (arg1))
3686 return non_lvalue (convert (type, arg0));
3687 if (integer_zerop (arg1))
3690 /* If we have ((a * C1) / C2) and C1 % C2 == 0, we can replace this with
3691 (a * (C1/C2). Also look for when we have a SAVE_EXPR in
3693 if (TREE_CODE (arg1) == INTEGER_CST
3694 && TREE_INT_CST_LOW (arg1) > 0 && TREE_INT_CST_HIGH (arg1) == 0
3695 && TREE_CODE (arg0) == MULT_EXPR
3696 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
3697 && TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) > 0
3698 && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
3699 && 0 == (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))
3700 % TREE_INT_CST_LOW (arg1)))
3703 = build_int_2 (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))
3704 / TREE_INT_CST_LOW (arg1), 0);
3706 TREE_TYPE (new_op) = type;
3707 return build (MULT_EXPR, type, TREE_OPERAND (arg0, 0), new_op);
3710 else if (TREE_CODE (arg1) == INTEGER_CST
3711 && TREE_INT_CST_LOW (arg1) > 0 && TREE_INT_CST_HIGH (arg1) == 0
3712 && TREE_CODE (arg0) == SAVE_EXPR
3713 && TREE_CODE (TREE_OPERAND (arg0, 0)) == MULT_EXPR
3714 && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1))
3716 && (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1))
3718 && (TREE_INT_CST_HIGH (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1))
3720 && (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1))
3721 % TREE_INT_CST_LOW (arg1)) == 0)
3724 = build_int_2 (TREE_INT_CST_LOW (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1))
3725 / TREE_INT_CST_LOW (arg1), 0);
3727 TREE_TYPE (new_op) = type;
3728 return build (MULT_EXPR, type,
3729 TREE_OPERAND (TREE_OPERAND (arg0, 0), 0), new_op);
3732 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3733 #ifndef REAL_INFINITY
3734 if (TREE_CODE (arg1) == REAL_CST
3735 && real_zerop (arg1))
3738 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3743 case FLOOR_MOD_EXPR:
3744 case ROUND_MOD_EXPR:
3745 case TRUNC_MOD_EXPR:
3746 if (integer_onep (arg1))
3747 return omit_one_operand (type, integer_zero_node, arg0);
3748 if (integer_zerop (arg1))
3756 if (integer_zerop (arg1))
3757 return non_lvalue (convert (type, arg0));
3758 /* Since negative shift count is not well-defined,
3759 don't try to compute it in the compiler. */
3760 if (tree_int_cst_lt (arg1, integer_zero_node))
3765 if (operand_equal_p (arg0, arg1, 0))
3767 if (TREE_CODE (type) == INTEGER_TYPE
3768 && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
3769 return omit_one_operand (type, arg1, arg0);
3773 if (operand_equal_p (arg0, arg1, 0))
3775 if (TREE_CODE (type) == INTEGER_TYPE
3776 && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
3777 return omit_one_operand (type, arg1, arg0);
3780 case TRUTH_NOT_EXPR:
3781 /* Note that the operand of this must be an int
3782 and its values must be 0 or 1.
3783 ("true" is a fixed value perhaps depending on the language,
3784 but we don't handle values other than 1 correctly yet.) */
3785 return invert_truthvalue (arg0);
3787 case TRUTH_ANDIF_EXPR:
3788 /* Note that the operands of this must be ints
3789 and their values must be 0 or 1.
3790 ("true" is a fixed value perhaps depending on the language.) */
3791 /* If first arg is constant zero, return it. */
3792 if (integer_zerop (arg0))
3794 case TRUTH_AND_EXPR:
3795 /* If either arg is constant true, drop it. */
3796 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
3797 return non_lvalue (arg1);
3798 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
3799 return non_lvalue (arg0);
3800 /* If second arg is constant zero, result is zero, but first arg
3801 must be evaluated. */
3802 if (integer_zerop (arg1))
3803 return omit_one_operand (type, arg1, arg0);
3806 /* Check for the possibility of merging component references. If our
3807 lhs is another similar operation, try to merge its rhs with our
3808 rhs. Then try to merge our lhs and rhs. */
3811 if (TREE_CODE (arg0) == code)
3813 tem = fold_truthop (code, type,
3814 TREE_OPERAND (arg0, 1), arg1);
3816 return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
3819 tem = fold_truthop (code, type, arg0, arg1);
3825 case TRUTH_ORIF_EXPR:
3826 /* Note that the operands of this must be ints
3827 and their values must be 0 or true.
3828 ("true" is a fixed value perhaps depending on the language.) */
3829 /* If first arg is constant true, return it. */
3830 if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
3833 /* If either arg is constant zero, drop it. */
3834 if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
3835 return non_lvalue (arg1);
3836 if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
3837 return non_lvalue (arg0);
3838 /* If second arg is constant true, result is true, but we must
3839 evaluate first arg. */
3840 if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
3841 return omit_one_operand (type, arg1, arg0);
3844 case TRUTH_XOR_EXPR:
3845 /* If either arg is constant zero, drop it. */
3846 if (integer_zerop (arg0))
3847 return non_lvalue (arg1);
3848 if (integer_zerop (arg1))
3849 return non_lvalue (arg0);
3850 /* If either arg is constant true, this is a logical inversion. */
3851 if (integer_onep (arg0))
3852 return non_lvalue (invert_truthvalue (arg1));
3853 if (integer_onep (arg1))
3854 return non_lvalue (invert_truthvalue (arg0));
3863 /* If one arg is a constant integer, put it last. */
3864 if (TREE_CODE (arg0) == INTEGER_CST
3865 && TREE_CODE (arg1) != INTEGER_CST)
3867 TREE_OPERAND (t, 0) = arg1;
3868 TREE_OPERAND (t, 1) = arg0;
3869 arg0 = TREE_OPERAND (t, 0);
3870 arg1 = TREE_OPERAND (t, 1);
3871 code = swap_tree_comparison (code);
3872 TREE_SET_CODE (t, code);
3875 /* Convert foo++ == CONST into ++foo == CONST + INCR.
3876 First, see if one arg is constant; find the constant arg
3877 and the other one. */
3879 tree constop = 0, varop;
3882 if (TREE_CONSTANT (arg1))
3883 constoploc = &TREE_OPERAND (t, 1), constop = arg1, varop = arg0;
3884 if (TREE_CONSTANT (arg0))
3885 constoploc = &TREE_OPERAND (t, 0), constop = arg0, varop = arg1;
3887 if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
3889 /* This optimization is invalid for ordered comparisons
3890 if CONST+INCR overflows or if foo+incr might overflow.
3891 This optimization is invalid for floating point due to rounding.
3892 For pointer types we assume overflow doesn't happen. */
3893 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
3894 || (TREE_CODE (TREE_TYPE (varop)) != REAL_TYPE
3895 && (code == EQ_EXPR || code == NE_EXPR)))
3898 = fold (build (PLUS_EXPR, TREE_TYPE (varop),
3899 constop, TREE_OPERAND (varop, 1)));
3900 TREE_SET_CODE (varop, PREINCREMENT_EXPR);
3901 *constoploc = newconst;
3905 else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
3907 if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE
3908 || (TREE_CODE (TREE_TYPE (varop)) != REAL_TYPE
3909 && (code == EQ_EXPR || code == NE_EXPR)))
3912 = fold (build (MINUS_EXPR, TREE_TYPE (varop),
3913 constop, TREE_OPERAND (varop, 1)));
3914 TREE_SET_CODE (varop, PREDECREMENT_EXPR);
3915 *constoploc = newconst;
3921 /* Change X >= CST to X > (CST - 1) if CST is positive. */
3922 if (TREE_CODE (arg1) == INTEGER_CST
3923 && TREE_CODE (arg0) != INTEGER_CST
3924 && ! tree_int_cst_lt (arg1, integer_one_node))
3926 switch (TREE_CODE (t))
3930 TREE_SET_CODE (t, code);
3931 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
3932 TREE_OPERAND (t, 1) = arg1;
3937 TREE_SET_CODE (t, code);
3938 arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
3939 TREE_OPERAND (t, 1) = arg1;
3943 /* If this is an EQ or NE comparison with zero and ARG0 is
3944 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
3945 two operations, but the latter can be done in one less insn
3946 one machine that have only two-operand insns or on which a
3947 constant cannot be the first operand. */
3948 if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
3949 && TREE_CODE (arg0) == BIT_AND_EXPR)
3951 if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
3952 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
3954 fold (build (code, type,
3955 build (BIT_AND_EXPR, TREE_TYPE (arg0),
3957 TREE_TYPE (TREE_OPERAND (arg0, 0)),
3958 TREE_OPERAND (arg0, 1),
3959 TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
3960 convert (TREE_TYPE (arg0),
3963 else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
3964 && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
3966 fold (build (code, type,
3967 build (BIT_AND_EXPR, TREE_TYPE (arg0),
3969 TREE_TYPE (TREE_OPERAND (arg0, 1)),
3970 TREE_OPERAND (arg0, 0),
3971 TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
3972 convert (TREE_TYPE (arg0),
3977 /* If this is an NE comparison of zero with an AND of one, remove the
3978 comparison since the AND will give the correct value. */
3979 if (code == NE_EXPR && integer_zerop (arg1)
3980 && TREE_CODE (arg0) == BIT_AND_EXPR
3981 && integer_onep (TREE_OPERAND (arg0, 1)))
3982 return convert (type, arg0);
3984 /* If we have (A & C) == C where C is a power of 2, convert this into
3985 (A & C) != 0. Similarly for NE_EXPR. */
3986 if ((code == EQ_EXPR || code == NE_EXPR)
3987 && TREE_CODE (arg0) == BIT_AND_EXPR
3988 && integer_pow2p (TREE_OPERAND (arg0, 1))
3989 && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
3990 return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
3991 arg0, integer_zero_node);
3993 /* Simplify comparison of something with itself. (For IEEE
3994 floating-point, we can only do some of these simplifications.) */
3995 if (operand_equal_p (arg0, arg1, 0))
4002 if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE)
4004 t = build_int_2 (1, 0);
4005 TREE_TYPE (t) = type;
4009 TREE_SET_CODE (t, code);
4013 /* For NE, we can only do this simplification if integer. */
4014 if (TREE_CODE (TREE_TYPE (arg0)) != INTEGER_TYPE)
4016 /* ... fall through ... */
4019 t = build_int_2 (0, 0);
4020 TREE_TYPE (t) = type;
4025 /* An unsigned comparison against 0 can be simplified. */
4026 if (integer_zerop (arg1)
4027 && (TREE_CODE (TREE_TYPE (arg1)) == INTEGER_TYPE
4028 || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE)
4029 && TREE_UNSIGNED (TREE_TYPE (arg1)))
4031 switch (TREE_CODE (t))
4035 TREE_SET_CODE (t, NE_EXPR);
4039 TREE_SET_CODE (t, EQ_EXPR);
4042 return omit_one_operand (integer_type_node,
4043 integer_one_node, arg0);
4045 return omit_one_operand (integer_type_node,
4046 integer_zero_node, arg0);
4050 /* If we are comparing an expression that just has comparisons
4051 of two integer values, arithmetic expressions of those comparisons,
4052 and constants, we can simplify it. There are only three cases
4053 to check: the two values can either be equal, the first can be
4054 greater, or the second can be greater. Fold the expression for
4055 those three values. Since each value must be 0 or 1, we have
4056 eight possibilities, each of which corresponds to the constant 0
4057 or 1 or one of the six possible comparisons.
4059 This handles common cases like (a > b) == 0 but also handles
4060 expressions like ((x > y) - (y > x)) > 0, which supposedly
4061 occur in macroized code. */
4063 if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
4065 tree cval1 = 0, cval2 = 0;
4067 if (twoval_comparison_p (arg0, &cval1, &cval2)
4068 /* Don't handle degenerate cases here; they should already
4069 have been handled anyway. */
4070 && cval1 != 0 && cval2 != 0
4071 && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
4072 && TREE_TYPE (cval1) == TREE_TYPE (cval2)
4073 && TREE_CODE (TREE_TYPE (cval1)) == INTEGER_TYPE
4074 && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
4075 TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
4077 tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
4078 tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
4080 /* We can't just pass T to eval_subst in case cval1 or cval2
4081 was the same as ARG1. */
4084 = fold (build (code, type,
4085 eval_subst (arg0, cval1, maxval, cval2, minval),
4088 = fold (build (code, type,
4089 eval_subst (arg0, cval1, maxval, cval2, maxval),
4092 = fold (build (code, type,
4093 eval_subst (arg0, cval1, minval, cval2, maxval),
4096 /* All three of these results should be 0 or 1. Confirm they
4097 are. Then use those values to select the proper code
4100 if ((integer_zerop (high_result)
4101 || integer_onep (high_result))
4102 && (integer_zerop (equal_result)
4103 || integer_onep (equal_result))
4104 && (integer_zerop (low_result)
4105 || integer_onep (low_result)))
4107 /* Make a 3-bit mask with the high-order bit being the
4108 value for `>', the next for '=', and the low for '<'. */
4109 switch ((integer_onep (high_result) * 4)
4110 + (integer_onep (equal_result) * 2)
4111 + integer_onep (low_result))
4115 return omit_one_operand (type, integer_zero_node, arg0);
4136 return omit_one_operand (type, integer_one_node, arg0);
4139 return fold (build (code, type, cval1, cval2));
4144 /* If this is a comparison of a field, we may be able to simplify it. */
4145 if ((TREE_CODE (arg0) == COMPONENT_REF
4146 || TREE_CODE (arg0) == BIT_FIELD_REF)
4147 && (code == EQ_EXPR || code == NE_EXPR)
4148 /* Handle the constant case even without -O
4149 to make sure the warnings are given. */
4150 && (optimize || TREE_CODE (arg1) == INTEGER_CST))
4152 t1 = optimize_bit_field_compare (code, type, arg0, arg1);
4156 /* From here on, the only cases we handle are when the result is
4157 known to be a constant.
4159 To compute GT, swap the arguments and do LT.
4160 To compute GE, do LT and invert the result.
4161 To compute LE, swap the arguments, do LT and invert the result.
4162 To compute NE, do EQ and invert the result.
4164 Therefore, the code below must handle only EQ and LT. */
4166 if (code == LE_EXPR || code == GT_EXPR)
4168 tem = arg0, arg0 = arg1, arg1 = tem;
4169 code = swap_tree_comparison (code);
4172 /* Note that it is safe to invert for real values here because we
4173 will check below in the one case that it matters. */
4176 if (code == NE_EXPR || code == GE_EXPR)
4179 code = invert_tree_comparison (code);
4182 /* Compute a result for LT or EQ if args permit;
4183 otherwise return T. */
4184 if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
4186 if (code == EQ_EXPR)
4187 t1 = build_int_2 ((TREE_INT_CST_LOW (arg0)
4188 == TREE_INT_CST_LOW (arg1))
4189 && (TREE_INT_CST_HIGH (arg0)
4190 == TREE_INT_CST_HIGH (arg1)),
4193 t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
4194 ? INT_CST_LT_UNSIGNED (arg0, arg1)
4195 : INT_CST_LT (arg0, arg1)),
4199 /* Assume a nonexplicit constant cannot equal an explicit one,
4200 since such code would be undefined anyway.
4201 Exception: on sysvr4, using #pragma weak,
4202 a label can come out as 0. */
4203 else if (TREE_CODE (arg1) == INTEGER_CST
4204 && !integer_zerop (arg1)
4205 && TREE_CONSTANT (arg0)
4206 && TREE_CODE (arg0) == ADDR_EXPR
4208 t1 = build_int_2 (0, 0);
4210 /* Two real constants can be compared explicitly. */
4211 else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
4213 /* If either operand is a NaN, the result is false with two
4214 exceptions: First, an NE_EXPR is true on NaNs, but that case
4215 is already handled correctly since we will be inverting the
4216 result for NE_EXPR. Second, if we had inverted a LE_EXPR
4217 or a GE_EXPR into a LT_EXPR, we must return true so that it
4218 will be inverted into false. */
4220 if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
4221 || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
4222 t1 = build_int_2 (invert && code == LT_EXPR, 0);
4224 else if (code == EQ_EXPR)
4225 t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
4226 TREE_REAL_CST (arg1)),
4229 t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
4230 TREE_REAL_CST (arg1)),
4234 if (t1 == NULL_TREE)
4238 TREE_INT_CST_LOW (t1) ^= 1;
4240 TREE_TYPE (t1) = type;
4244 if (TREE_CODE (arg0) == INTEGER_CST)
4245 return TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1));
4246 else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
4247 return omit_one_operand (type, arg1, arg0);
4249 /* If the second operand is zero, invert the comparison and swap
4250 the second and third operands. Likewise if the second operand
4251 is constant and the third is not or if the third operand is
4252 equivalent to the first operand of the comparison. */
4254 if (integer_zerop (arg1)
4255 || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
4256 || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4257 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
4258 TREE_OPERAND (t, 2),
4259 TREE_OPERAND (arg0, 1))))
4261 /* See if this can be inverted. If it can't, possibly because
4262 it was a floating-point inequality comparison, don't do
4264 tem = invert_truthvalue (arg0);
4266 if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
4268 arg0 = TREE_OPERAND (t, 0) = tem;
4269 TREE_OPERAND (t, 1) = TREE_OPERAND (t, 2);
4270 TREE_OPERAND (t, 2) = arg1;
4271 arg1 = TREE_OPERAND (t, 1);
4275 /* If we have A op B ? A : C, we may be able to convert this to a
4276 simpler expression, depending on the operation and the values
4277 of B and C. IEEE floating point prevents this though,
4278 because A or B might be -0.0 or a NaN. */
4280 if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
4281 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4282 || TREE_CODE (TREE_TYPE (TREE_OPERAND (arg0, 0))) != REAL_TYPE)
4283 && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
4284 arg1, TREE_OPERAND (arg0, 1)))
4286 tree arg2 = TREE_OPERAND (t, 2);
4287 enum tree_code comp_code = TREE_CODE (arg0);
4289 /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
4290 depending on the comparison operation. */
4291 if (integer_zerop (TREE_OPERAND (arg0, 1))
4292 && TREE_CODE (arg2) == NEGATE_EXPR
4293 && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
4297 return fold (build1 (NEGATE_EXPR, type, arg1));
4299 return convert (type, arg1);
4302 return fold (build1 (ABS_EXPR, type, arg1));
4305 return fold (build1 (NEGATE_EXPR, type,
4306 fold (build1 (ABS_EXPR, type, arg1))));
4309 /* If this is A != 0 ? A : 0, this is simply A. For ==, it is
4312 if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
4314 if (comp_code == NE_EXPR)
4315 return convert (type, arg1);
4316 else if (comp_code == EQ_EXPR)
4317 return convert (type, integer_zero_node);
4320 /* If this is A op B ? A : B, this is either A, B, min (A, B),
4321 or max (A, B), depending on the operation. */
4323 if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
4324 arg2, TREE_OPERAND (arg0, 0)))
4328 return convert (type, arg2);
4330 return convert (type, arg1);
4333 return fold (build (MIN_EXPR, type, arg1, arg2));
4336 return fold (build (MAX_EXPR, type, arg1, arg2));
4339 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4340 we might still be able to simplify this. For example,
4341 if C1 is one less or one more than C2, this might have started
4342 out as a MIN or MAX and been transformed by this function.
4343 Only good for INTEGER_TYPE, because we need TYPE_MAX_VALUE. */
4345 if (TREE_CODE (type) == INTEGER_TYPE
4346 && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
4347 && TREE_CODE (arg2) == INTEGER_CST)
4351 /* We can replace A with C1 in this case. */
4352 arg1 = TREE_OPERAND (t, 1)
4353 = convert (type, TREE_OPERAND (arg0, 1));
4357 /* If C1 is C2 + 1, this is min(A, C2). */
4358 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
4359 && operand_equal_p (TREE_OPERAND (arg0, 1),
4360 const_binop (PLUS_EXPR, arg2,
4361 integer_one_node, 0), 1))
4362 return fold (build (MIN_EXPR, type, arg1, arg2));
4366 /* If C1 is C2 - 1, this is min(A, C2). */
4367 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
4368 && operand_equal_p (TREE_OPERAND (arg0, 1),
4369 const_binop (MINUS_EXPR, arg2,
4370 integer_one_node, 0), 1))
4371 return fold (build (MIN_EXPR, type, arg1, arg2));
4375 /* If C1 is C2 - 1, this is max(A, C2). */
4376 if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
4377 && operand_equal_p (TREE_OPERAND (arg0, 1),
4378 const_binop (MINUS_EXPR, arg2,
4379 integer_one_node, 0), 1))
4380 return fold (build (MAX_EXPR, type, arg1, arg2));
4384 /* If C1 is C2 + 1, this is max(A, C2). */
4385 if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
4386 && operand_equal_p (TREE_OPERAND (arg0, 1),
4387 const_binop (PLUS_EXPR, arg2,
4388 integer_one_node, 0), 1))
4389 return fold (build (MAX_EXPR, type, arg1, arg2));
4394 /* Convert A ? 1 : 0 to simply A. */
4395 if (integer_onep (TREE_OPERAND (t, 1))
4396 && integer_zerop (TREE_OPERAND (t, 2))
4397 /* If we try to convert TREE_OPERAND (t, 0) to our type, the
4398 call to fold will try to move the conversion inside
4399 a COND, which will recurse. In that case, the COND_EXPR
4400 is probably the best choice, so leave it alone. */
4401 && type == TREE_TYPE (arg0))
4405 /* Look for expressions of the form A & 2 ? 2 : 0. The result of this
4406 operation is simply A & 2. */
4408 if (integer_zerop (TREE_OPERAND (t, 2))
4409 && TREE_CODE (arg0) == NE_EXPR
4410 && integer_zerop (TREE_OPERAND (arg0, 1))
4411 && integer_pow2p (arg1)
4412 && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
4413 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
4415 return convert (type, TREE_OPERAND (arg0, 0));
4420 /* When pedantic, a compound expression can be neither an lvalue
4421 nor an integer constant expression. */
4422 if (TREE_SIDE_EFFECTS (arg0) || pedantic)
4424 /* Don't let (0, 0) be null pointer constant. */
4425 if (integer_zerop (arg1))
4426 return non_lvalue (arg1);
4431 return build_complex (arg0, arg1);
4435 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4437 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4438 return omit_one_operand (type, TREE_OPERAND (arg0, 0),
4439 TREE_OPERAND (arg0, 1));
4440 else if (TREE_CODE (arg0) == COMPLEX_CST)
4441 return TREE_REALPART (arg0);
4442 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4443 return build_binary_op (TREE_CODE (arg0), type,
4444 build_unary_op (REALPART_EXPR,
4445 TREE_OPERAND (arg0, 0),
4447 build_unary_op (REALPART_EXPR,
4448 TREE_OPERAND (arg0, 1),
4454 if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
4455 return convert (type, integer_zero_node);
4456 else if (TREE_CODE (arg0) == COMPLEX_EXPR)
4457 return omit_one_operand (type, TREE_OPERAND (arg0, 1),
4458 TREE_OPERAND (arg0, 0));
4459 else if (TREE_CODE (arg0) == COMPLEX_CST)
4460 return TREE_IMAGPART (arg0);
4461 else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
4462 return build_binary_op (TREE_CODE (arg0), type,
4463 build_unary_op (IMAGPART_EXPR,
4464 TREE_OPERAND (arg0, 0),
4466 build_unary_op (IMAGPART_EXPR,
4467 TREE_OPERAND (arg0, 1),
4474 } /* switch (code) */