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Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 5701 |
1 files changed, 0 insertions, 5701 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c deleted file mode 100644 index f75d479637e..00000000000 --- a/gcc/fold-const.c +++ /dev/null @@ -1,5701 +0,0 @@ -/* Fold a constant sub-tree into a single node for C-compiler - Copyright (C) 1987, 88, 92-96, 1997 Free Software Foundation, Inc. - -This file is part of GNU CC. - -GNU CC is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU CC is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GNU CC; see the file COPYING. If not, write to -the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02111-1307, USA. */ - -/*@@ This file should be rewritten to use an arbitrary precision - @@ representation for "struct tree_int_cst" and "struct tree_real_cst". - @@ Perhaps the routines could also be used for bc/dc, and made a lib. - @@ The routines that translate from the ap rep should - @@ warn if precision et. al. is lost. - @@ This would also make life easier when this technology is used - @@ for cross-compilers. */ - - -/* The entry points in this file are fold, size_int and size_binop. - - fold takes a tree as argument and returns a simplified tree. - - size_binop takes a tree code for an arithmetic operation - and two operands that are trees, and produces a tree for the - result, assuming the type comes from `sizetype'. - - size_int takes an integer value, and creates a tree constant - with type from `sizetype'. */ - -#include <stdio.h> -#include <setjmp.h> -#include "config.h" -#include "flags.h" -#include "tree.h" - -/* Handle floating overflow for `const_binop'. */ -static jmp_buf float_error; - -static void encode PROTO((HOST_WIDE_INT *, - HOST_WIDE_INT, HOST_WIDE_INT)); -static void decode PROTO((HOST_WIDE_INT *, - HOST_WIDE_INT *, HOST_WIDE_INT *)); -int div_and_round_double PROTO((enum tree_code, int, HOST_WIDE_INT, - HOST_WIDE_INT, HOST_WIDE_INT, - HOST_WIDE_INT, HOST_WIDE_INT *, - HOST_WIDE_INT *, HOST_WIDE_INT *, - HOST_WIDE_INT *)); -static int split_tree PROTO((tree, enum tree_code, tree *, - tree *, int *)); -static tree const_binop PROTO((enum tree_code, tree, tree, int)); -static tree fold_convert PROTO((tree, tree)); -static enum tree_code invert_tree_comparison PROTO((enum tree_code)); -static enum tree_code swap_tree_comparison PROTO((enum tree_code)); -static int truth_value_p PROTO((enum tree_code)); -static int operand_equal_for_comparison_p PROTO((tree, tree, tree)); -static int twoval_comparison_p PROTO((tree, tree *, tree *, int *)); -static tree eval_subst PROTO((tree, tree, tree, tree, tree)); -static tree omit_one_operand PROTO((tree, tree, tree)); -static tree pedantic_omit_one_operand PROTO((tree, tree, tree)); -static tree distribute_bit_expr PROTO((enum tree_code, tree, tree, tree)); -static tree make_bit_field_ref PROTO((tree, tree, int, int, int)); -static tree optimize_bit_field_compare PROTO((enum tree_code, tree, - tree, tree)); -static tree decode_field_reference PROTO((tree, int *, int *, - enum machine_mode *, int *, - int *, tree *, tree *)); -static int all_ones_mask_p PROTO((tree, int)); -static int simple_operand_p PROTO((tree)); -static tree range_binop PROTO((enum tree_code, tree, tree, int, - tree, int)); -static tree make_range PROTO((tree, int *, tree *, tree *)); -static tree build_range_check PROTO((tree, tree, int, tree, tree)); -static int merge_ranges PROTO((int *, tree *, tree *, int, tree, tree, - int, tree, tree)); -static tree fold_range_test PROTO((tree)); -static tree unextend PROTO((tree, int, int, tree)); -static tree fold_truthop PROTO((enum tree_code, tree, tree, tree)); -static tree strip_compound_expr PROTO((tree, tree)); - -#ifndef BRANCH_COST -#define BRANCH_COST 1 -#endif - -/* Suppose A1 + B1 = SUM1, using 2's complement arithmetic ignoring overflow. - Suppose A, B and SUM have the same respective signs as A1, B1, and SUM1. - Then this yields nonzero if overflow occurred during the addition. - Overflow occurs if A and B have the same sign, but A and SUM differ in sign. - Use `^' to test whether signs differ, and `< 0' to isolate the sign. */ -#define overflow_sum_sign(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0) - -/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic. - We do that by representing the two-word integer in 4 words, with only - HOST_BITS_PER_WIDE_INT/2 bits stored in each word, as a positive number. */ - -#define LOWPART(x) \ - ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT/2)) - 1)) -#define HIGHPART(x) \ - ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT/2) -#define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT/2) - -/* Unpack a two-word integer into 4 words. - LOW and HI are the integer, as two `HOST_WIDE_INT' pieces. - WORDS points to the array of HOST_WIDE_INTs. */ - -static void -encode (words, low, hi) - HOST_WIDE_INT *words; - HOST_WIDE_INT low, hi; -{ - words[0] = LOWPART (low); - words[1] = HIGHPART (low); - words[2] = LOWPART (hi); - words[3] = HIGHPART (hi); -} - -/* Pack an array of 4 words into a two-word integer. - WORDS points to the array of words. - The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */ - -static void -decode (words, low, hi) - HOST_WIDE_INT *words; - HOST_WIDE_INT *low, *hi; -{ - *low = words[0] | words[1] * BASE; - *hi = words[2] | words[3] * BASE; -} - -/* Make the integer constant T valid for its type - by setting to 0 or 1 all the bits in the constant - that don't belong in the type. - Yield 1 if a signed overflow occurs, 0 otherwise. - If OVERFLOW is nonzero, a signed overflow has already occurred - in calculating T, so propagate it. - - Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE, - if it exists. */ - -int -force_fit_type (t, overflow) - tree t; - int overflow; -{ - HOST_WIDE_INT low, high; - register int prec; - - if (TREE_CODE (t) == REAL_CST) - { -#ifdef CHECK_FLOAT_VALUE - CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t), - overflow); -#endif - return overflow; - } - - else if (TREE_CODE (t) != INTEGER_CST) - return overflow; - - low = TREE_INT_CST_LOW (t); - high = TREE_INT_CST_HIGH (t); - - if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE) - prec = POINTER_SIZE; - else - prec = TYPE_PRECISION (TREE_TYPE (t)); - - /* First clear all bits that are beyond the type's precision. */ - - if (prec == 2 * HOST_BITS_PER_WIDE_INT) - ; - else if (prec > HOST_BITS_PER_WIDE_INT) - { - TREE_INT_CST_HIGH (t) - &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); - } - else - { - TREE_INT_CST_HIGH (t) = 0; - if (prec < HOST_BITS_PER_WIDE_INT) - TREE_INT_CST_LOW (t) &= ~((HOST_WIDE_INT) (-1) << prec); - } - - /* Unsigned types do not suffer sign extension or overflow. */ - if (TREE_UNSIGNED (TREE_TYPE (t))) - return overflow; - - /* If the value's sign bit is set, extend the sign. */ - if (prec != 2 * HOST_BITS_PER_WIDE_INT - && (prec > HOST_BITS_PER_WIDE_INT - ? (TREE_INT_CST_HIGH (t) - & ((HOST_WIDE_INT) 1 << (prec - HOST_BITS_PER_WIDE_INT - 1))) - : TREE_INT_CST_LOW (t) & ((HOST_WIDE_INT) 1 << (prec - 1)))) - { - /* Value is negative: - set to 1 all the bits that are outside this type's precision. */ - if (prec > HOST_BITS_PER_WIDE_INT) - { - TREE_INT_CST_HIGH (t) - |= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT)); - } - else - { - TREE_INT_CST_HIGH (t) = -1; - if (prec < HOST_BITS_PER_WIDE_INT) - TREE_INT_CST_LOW (t) |= ((HOST_WIDE_INT) (-1) << prec); - } - } - - /* Yield nonzero if signed overflow occurred. */ - return - ((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t))) - != 0); -} - -/* Add two doubleword integers with doubleword result. - Each argument is given as two `HOST_WIDE_INT' pieces. - One argument is L1 and H1; the other, L2 and H2. - The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -int -add_double (l1, h1, l2, h2, lv, hv) - HOST_WIDE_INT l1, h1, l2, h2; - HOST_WIDE_INT *lv, *hv; -{ - HOST_WIDE_INT l, h; - - l = l1 + l2; - h = h1 + h2 + ((unsigned HOST_WIDE_INT) l < l1); - - *lv = l; - *hv = h; - return overflow_sum_sign (h1, h2, h); -} - -/* Negate a doubleword integer with doubleword result. - Return nonzero if the operation overflows, assuming it's signed. - The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1. - The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -int -neg_double (l1, h1, lv, hv) - HOST_WIDE_INT l1, h1; - HOST_WIDE_INT *lv, *hv; -{ - if (l1 == 0) - { - *lv = 0; - *hv = - h1; - return (*hv & h1) < 0; - } - else - { - *lv = - l1; - *hv = ~ h1; - return 0; - } -} - -/* Multiply two doubleword integers with doubleword result. - Return nonzero if the operation overflows, assuming it's signed. - Each argument is given as two `HOST_WIDE_INT' pieces. - One argument is L1 and H1; the other, L2 and H2. - The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -int -mul_double (l1, h1, l2, h2, lv, hv) - HOST_WIDE_INT l1, h1, l2, h2; - HOST_WIDE_INT *lv, *hv; -{ - HOST_WIDE_INT arg1[4]; - HOST_WIDE_INT arg2[4]; - HOST_WIDE_INT prod[4 * 2]; - register unsigned HOST_WIDE_INT carry; - register int i, j, k; - HOST_WIDE_INT toplow, tophigh, neglow, neghigh; - - encode (arg1, l1, h1); - encode (arg2, l2, h2); - - bzero ((char *) prod, sizeof prod); - - for (i = 0; i < 4; i++) - { - carry = 0; - for (j = 0; j < 4; j++) - { - k = i + j; - /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */ - carry += arg1[i] * arg2[j]; - /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */ - carry += prod[k]; - prod[k] = LOWPART (carry); - carry = HIGHPART (carry); - } - prod[i + 4] = carry; - } - - decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */ - - /* Check for overflow by calculating the top half of the answer in full; - it should agree with the low half's sign bit. */ - decode (prod+4, &toplow, &tophigh); - if (h1 < 0) - { - neg_double (l2, h2, &neglow, &neghigh); - add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); - } - if (h2 < 0) - { - neg_double (l1, h1, &neglow, &neghigh); - add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh); - } - return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0; -} - -/* Shift the doubleword integer in L1, H1 left by COUNT places - keeping only PREC bits of result. - Shift right if COUNT is negative. - ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. - Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -void -lshift_double (l1, h1, count, prec, lv, hv, arith) - HOST_WIDE_INT l1, h1, count; - int prec; - HOST_WIDE_INT *lv, *hv; - int arith; -{ - if (count < 0) - { - rshift_double (l1, h1, - count, prec, lv, hv, arith); - return; - } - -#ifdef SHIFT_COUNT_TRUNCATED - if (SHIFT_COUNT_TRUNCATED) - count %= prec; -#endif - - if (count >= HOST_BITS_PER_WIDE_INT) - { - *hv = (unsigned HOST_WIDE_INT) l1 << count - HOST_BITS_PER_WIDE_INT; - *lv = 0; - } - else - { - *hv = (((unsigned HOST_WIDE_INT) h1 << count) - | ((unsigned HOST_WIDE_INT) l1 >> HOST_BITS_PER_WIDE_INT - count - 1 >> 1)); - *lv = (unsigned HOST_WIDE_INT) l1 << count; - } -} - -/* Shift the doubleword integer in L1, H1 right by COUNT places - keeping only PREC bits of result. COUNT must be positive. - ARITH nonzero specifies arithmetic shifting; otherwise use logical shift. - Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -void -rshift_double (l1, h1, count, prec, lv, hv, arith) - HOST_WIDE_INT l1, h1, count; - int prec; - HOST_WIDE_INT *lv, *hv; - int arith; -{ - unsigned HOST_WIDE_INT signmask; - signmask = (arith - ? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1)) - : 0); - -#ifdef SHIFT_COUNT_TRUNCATED - if (SHIFT_COUNT_TRUNCATED) - count %= prec; -#endif - - if (count >= HOST_BITS_PER_WIDE_INT) - { - *hv = signmask; - *lv = ((signmask << 2 * HOST_BITS_PER_WIDE_INT - count - 1 << 1) - | ((unsigned HOST_WIDE_INT) h1 >> count - HOST_BITS_PER_WIDE_INT)); - } - else - { - *lv = (((unsigned HOST_WIDE_INT) l1 >> count) - | ((unsigned HOST_WIDE_INT) h1 << HOST_BITS_PER_WIDE_INT - count - 1 << 1)); - *hv = ((signmask << HOST_BITS_PER_WIDE_INT - count) - | ((unsigned HOST_WIDE_INT) h1 >> count)); - } -} - -/* Rotate the doubleword integer in L1, H1 left by COUNT places - keeping only PREC bits of result. - Rotate right if COUNT is negative. - Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -void -lrotate_double (l1, h1, count, prec, lv, hv) - HOST_WIDE_INT l1, h1, count; - int prec; - HOST_WIDE_INT *lv, *hv; -{ - HOST_WIDE_INT s1l, s1h, s2l, s2h; - - count %= prec; - if (count < 0) - count += prec; - - lshift_double (l1, h1, count, prec, &s1l, &s1h, 0); - rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0); - *lv = s1l | s2l; - *hv = s1h | s2h; -} - -/* Rotate the doubleword integer in L1, H1 left by COUNT places - keeping only PREC bits of result. COUNT must be positive. - Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */ - -void -rrotate_double (l1, h1, count, prec, lv, hv) - HOST_WIDE_INT l1, h1, count; - int prec; - HOST_WIDE_INT *lv, *hv; -{ - HOST_WIDE_INT s1l, s1h, s2l, s2h; - - count %= prec; - if (count < 0) - count += prec; - - rshift_double (l1, h1, count, prec, &s1l, &s1h, 0); - lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0); - *lv = s1l | s2l; - *hv = s1h | s2h; -} - -/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN - for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM). - CODE is a tree code for a kind of division, one of - TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR - or EXACT_DIV_EXPR - It controls how the quotient is rounded to a integer. - Return nonzero if the operation overflows. - UNS nonzero says do unsigned division. */ - -int -div_and_round_double (code, uns, - lnum_orig, hnum_orig, lden_orig, hden_orig, - lquo, hquo, lrem, hrem) - enum tree_code code; - int uns; - HOST_WIDE_INT lnum_orig, hnum_orig; /* num == numerator == dividend */ - HOST_WIDE_INT lden_orig, hden_orig; /* den == denominator == divisor */ - HOST_WIDE_INT *lquo, *hquo, *lrem, *hrem; -{ - int quo_neg = 0; - HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */ - HOST_WIDE_INT den[4], quo[4]; - register int i, j; - unsigned HOST_WIDE_INT work; - register unsigned HOST_WIDE_INT carry = 0; - HOST_WIDE_INT lnum = lnum_orig; - HOST_WIDE_INT hnum = hnum_orig; - HOST_WIDE_INT lden = lden_orig; - HOST_WIDE_INT hden = hden_orig; - int overflow = 0; - - if ((hden == 0) && (lden == 0)) - abort (); - - /* calculate quotient sign and convert operands to unsigned. */ - if (!uns) - { - if (hnum < 0) - { - quo_neg = ~ quo_neg; - /* (minimum integer) / (-1) is the only overflow case. */ - if (neg_double (lnum, hnum, &lnum, &hnum) && (lden & hden) == -1) - overflow = 1; - } - if (hden < 0) - { - quo_neg = ~ quo_neg; - neg_double (lden, hden, &lden, &hden); - } - } - - if (hnum == 0 && hden == 0) - { /* single precision */ - *hquo = *hrem = 0; - /* This unsigned division rounds toward zero. */ - *lquo = lnum / (unsigned HOST_WIDE_INT) lden; - goto finish_up; - } - - if (hnum == 0) - { /* trivial case: dividend < divisor */ - /* hden != 0 already checked. */ - *hquo = *lquo = 0; - *hrem = hnum; - *lrem = lnum; - goto finish_up; - } - - bzero ((char *) quo, sizeof quo); - - bzero ((char *) num, sizeof num); /* to zero 9th element */ - bzero ((char *) den, sizeof den); - - encode (num, lnum, hnum); - encode (den, lden, hden); - - /* Special code for when the divisor < BASE. */ - if (hden == 0 && lden < BASE) - { - /* hnum != 0 already checked. */ - for (i = 4 - 1; i >= 0; i--) - { - work = num[i] + carry * BASE; - quo[i] = work / (unsigned HOST_WIDE_INT) lden; - carry = work % (unsigned HOST_WIDE_INT) lden; - } - } - else - { - /* Full double precision division, - with thanks to Don Knuth's "Seminumerical Algorithms". */ - int num_hi_sig, den_hi_sig; - unsigned HOST_WIDE_INT quo_est, scale; - - /* Find the highest non-zero divisor digit. */ - for (i = 4 - 1; ; i--) - if (den[i] != 0) { - den_hi_sig = i; - break; - } - - /* Insure that the first digit of the divisor is at least BASE/2. - This is required by the quotient digit estimation algorithm. */ - - scale = BASE / (den[den_hi_sig] + 1); - if (scale > 1) { /* scale divisor and dividend */ - carry = 0; - for (i = 0; i <= 4 - 1; i++) { - work = (num[i] * scale) + carry; - num[i] = LOWPART (work); - carry = HIGHPART (work); - } num[4] = carry; - carry = 0; - for (i = 0; i <= 4 - 1; i++) { - work = (den[i] * scale) + carry; - den[i] = LOWPART (work); - carry = HIGHPART (work); - if (den[i] != 0) den_hi_sig = i; - } - } - - num_hi_sig = 4; - - /* Main loop */ - for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--) { - /* guess the next quotient digit, quo_est, by dividing the first - two remaining dividend digits by the high order quotient digit. - quo_est is never low and is at most 2 high. */ - unsigned HOST_WIDE_INT tmp; - - num_hi_sig = i + den_hi_sig + 1; - work = num[num_hi_sig] * BASE + num[num_hi_sig - 1]; - if (num[num_hi_sig] != den[den_hi_sig]) - quo_est = work / den[den_hi_sig]; - else - quo_est = BASE - 1; - - /* refine quo_est so it's usually correct, and at most one high. */ - tmp = work - quo_est * den[den_hi_sig]; - if (tmp < BASE - && den[den_hi_sig - 1] * quo_est > (tmp * BASE + num[num_hi_sig - 2])) - quo_est--; - - /* Try QUO_EST as the quotient digit, by multiplying the - divisor by QUO_EST and subtracting from the remaining dividend. - Keep in mind that QUO_EST is the I - 1st digit. */ - - carry = 0; - for (j = 0; j <= den_hi_sig; j++) - { - work = quo_est * den[j] + carry; - carry = HIGHPART (work); - work = num[i + j] - LOWPART (work); - num[i + j] = LOWPART (work); - carry += HIGHPART (work) != 0; - } - - /* if quo_est was high by one, then num[i] went negative and - we need to correct things. */ - - if (num[num_hi_sig] < carry) - { - quo_est--; - carry = 0; /* add divisor back in */ - for (j = 0; j <= den_hi_sig; j++) - { - work = num[i + j] + den[j] + carry; - carry = HIGHPART (work); - num[i + j] = LOWPART (work); - } - num [num_hi_sig] += carry; - } - - /* store the quotient digit. */ - quo[i] = quo_est; - } - } - - decode (quo, lquo, hquo); - - finish_up: - /* if result is negative, make it so. */ - if (quo_neg) - neg_double (*lquo, *hquo, lquo, hquo); - - /* compute trial remainder: rem = num - (quo * den) */ - mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); - neg_double (*lrem, *hrem, lrem, hrem); - add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); - - switch (code) - { - case TRUNC_DIV_EXPR: - case TRUNC_MOD_EXPR: /* round toward zero */ - case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */ - return overflow; - - case FLOOR_DIV_EXPR: - case FLOOR_MOD_EXPR: /* round toward negative infinity */ - if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */ - { - /* quo = quo - 1; */ - add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, - lquo, hquo); - } - else return overflow; - break; - - case CEIL_DIV_EXPR: - case CEIL_MOD_EXPR: /* round toward positive infinity */ - if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */ - { - add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, - lquo, hquo); - } - else return overflow; - break; - - case ROUND_DIV_EXPR: - case ROUND_MOD_EXPR: /* round to closest integer */ - { - HOST_WIDE_INT labs_rem = *lrem, habs_rem = *hrem; - HOST_WIDE_INT labs_den = lden, habs_den = hden, ltwice, htwice; - - /* get absolute values */ - if (*hrem < 0) neg_double (*lrem, *hrem, &labs_rem, &habs_rem); - if (hden < 0) neg_double (lden, hden, &labs_den, &habs_den); - - /* if (2 * abs (lrem) >= abs (lden)) */ - mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0, - labs_rem, habs_rem, <wice, &htwice); - if (((unsigned HOST_WIDE_INT) habs_den - < (unsigned HOST_WIDE_INT) htwice) - || (((unsigned HOST_WIDE_INT) habs_den - == (unsigned HOST_WIDE_INT) htwice) - && ((HOST_WIDE_INT unsigned) labs_den - < (unsigned HOST_WIDE_INT) ltwice))) - { - if (*hquo < 0) - /* quo = quo - 1; */ - add_double (*lquo, *hquo, - (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo); - else - /* quo = quo + 1; */ - add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0, - lquo, hquo); - } - else return overflow; - } - break; - - default: - abort (); - } - - /* compute true remainder: rem = num - (quo * den) */ - mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem); - neg_double (*lrem, *hrem, lrem, hrem); - add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem); - return overflow; -} - -#ifndef REAL_ARITHMETIC -/* Effectively truncate a real value to represent the nearest possible value - in a narrower mode. The result is actually represented in the same data - type as the argument, but its value is usually different. - - A trap may occur during the FP operations and it is the responsibility - of the calling function to have a handler established. */ - -REAL_VALUE_TYPE -real_value_truncate (mode, arg) - enum machine_mode mode; - REAL_VALUE_TYPE arg; -{ - return REAL_VALUE_TRUNCATE (mode, arg); -} - -#if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT - -/* Check for infinity in an IEEE double precision number. */ - -int -target_isinf (x) - REAL_VALUE_TYPE x; -{ - /* The IEEE 64-bit double format. */ - union { - REAL_VALUE_TYPE d; - struct { - unsigned sign : 1; - unsigned exponent : 11; - unsigned mantissa1 : 20; - unsigned mantissa2; - } little_endian; - struct { - unsigned mantissa2; - unsigned mantissa1 : 20; - unsigned exponent : 11; - unsigned sign : 1; - } big_endian; - } u; - - u.d = dconstm1; - if (u.big_endian.sign == 1) - { - u.d = x; - return (u.big_endian.exponent == 2047 - && u.big_endian.mantissa1 == 0 - && u.big_endian.mantissa2 == 0); - } - else - { - u.d = x; - return (u.little_endian.exponent == 2047 - && u.little_endian.mantissa1 == 0 - && u.little_endian.mantissa2 == 0); - } -} - -/* Check whether an IEEE double precision number is a NaN. */ - -int -target_isnan (x) - REAL_VALUE_TYPE x; -{ - /* The IEEE 64-bit double format. */ - union { - REAL_VALUE_TYPE d; - struct { - unsigned sign : 1; - unsigned exponent : 11; - unsigned mantissa1 : 20; - unsigned mantissa2; - } little_endian; - struct { - unsigned mantissa2; - unsigned mantissa1 : 20; - unsigned exponent : 11; - unsigned sign : 1; - } big_endian; - } u; - - u.d = dconstm1; - if (u.big_endian.sign == 1) - { - u.d = x; - return (u.big_endian.exponent == 2047 - && (u.big_endian.mantissa1 != 0 - || u.big_endian.mantissa2 != 0)); - } - else - { - u.d = x; - return (u.little_endian.exponent == 2047 - && (u.little_endian.mantissa1 != 0 - || u.little_endian.mantissa2 != 0)); - } -} - -/* Check for a negative IEEE double precision number. */ - -int -target_negative (x) - REAL_VALUE_TYPE x; -{ - /* The IEEE 64-bit double format. */ - union { - REAL_VALUE_TYPE d; - struct { - unsigned sign : 1; - unsigned exponent : 11; - unsigned mantissa1 : 20; - unsigned mantissa2; - } little_endian; - struct { - unsigned mantissa2; - unsigned mantissa1 : 20; - unsigned exponent : 11; - unsigned sign : 1; - } big_endian; - } u; - - u.d = dconstm1; - if (u.big_endian.sign == 1) - { - u.d = x; - return u.big_endian.sign; - } - else - { - u.d = x; - return u.little_endian.sign; - } -} -#else /* Target not IEEE */ - -/* Let's assume other float formats don't have infinity. - (This can be overridden by redefining REAL_VALUE_ISINF.) */ - -target_isinf (x) - REAL_VALUE_TYPE x; -{ - return 0; -} - -/* Let's assume other float formats don't have NaNs. - (This can be overridden by redefining REAL_VALUE_ISNAN.) */ - -target_isnan (x) - REAL_VALUE_TYPE x; -{ - return 0; -} - -/* Let's assume other float formats don't have minus zero. - (This can be overridden by redefining REAL_VALUE_NEGATIVE.) */ - -target_negative (x) - REAL_VALUE_TYPE x; -{ - return x < 0; -} -#endif /* Target not IEEE */ - -/* Try to change R into its exact multiplicative inverse in machine mode - MODE. Return nonzero function value if successful. */ - -int -exact_real_inverse (mode, r) - enum machine_mode mode; - REAL_VALUE_TYPE *r; -{ - union - { - double d; - unsigned short i[4]; - }x, t, y; - int i; - - /* Usually disable if bounds checks are not reliable. */ - if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float) - return 0; - - /* Set array index to the less significant bits in the unions, depending - on the endian-ness of the host doubles. - Disable if insufficient information on the data structure. */ -#if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT - return 0; -#else -#if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT -#define K 2 -#else -#if HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT -#define K 2 -#else -#define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN) -#endif -#endif -#endif - - if (setjmp (float_error)) - { - /* Don't do the optimization if there was an arithmetic error. */ -fail: - set_float_handler (NULL_PTR); - return 0; - } - set_float_handler (float_error); - - /* Domain check the argument. */ - x.d = *r; - if (x.d == 0.0) - goto fail; - -#ifdef REAL_INFINITY - if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d)) - goto fail; -#endif - - /* Compute the reciprocal and check for numerical exactness. - It is unnecessary to check all the significand bits to determine - whether X is a power of 2. If X is not, then it is impossible for - the bottom half significand of both X and 1/X to be all zero bits. - Hence we ignore the data structure of the top half and examine only - the low order bits of the two significands. */ - t.d = 1.0 / x.d; - if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0) - goto fail; - - /* Truncate to the required mode and range-check the result. */ - y.d = REAL_VALUE_TRUNCATE (mode, t.d); -#ifdef CHECK_FLOAT_VALUE - i = 0; - if (CHECK_FLOAT_VALUE (mode, y.d, i)) - goto fail; -#endif - - /* Fail if truncation changed the value. */ - if (y.d != t.d || y.d == 0.0) - goto fail; - -#ifdef REAL_INFINITY - if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d)) - goto fail; -#endif - - /* Output the reciprocal and return success flag. */ - set_float_handler (NULL_PTR); - *r = y.d; - return 1; -} -#endif /* no REAL_ARITHMETIC */ - -/* Split a tree IN into a constant and a variable part - that could be combined with CODE to make IN. - CODE must be a commutative arithmetic operation. - Store the constant part into *CONP and the variable in &VARP. - Return 1 if this was done; zero means the tree IN did not decompose - this way. - - If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. - Therefore, we must tell the caller whether the variable part - was subtracted. We do this by storing 1 or -1 into *VARSIGNP. - The value stored is the coefficient for the variable term. - The constant term we return should always be added; - we negate it if necessary. */ - -static int -split_tree (in, code, varp, conp, varsignp) - tree in; - enum tree_code code; - tree *varp, *conp; - int *varsignp; -{ - register tree outtype = TREE_TYPE (in); - *varp = 0; - *conp = 0; - - /* Strip any conversions that don't change the machine mode. */ - while ((TREE_CODE (in) == NOP_EXPR - || TREE_CODE (in) == CONVERT_EXPR) - && (TYPE_MODE (TREE_TYPE (in)) - == TYPE_MODE (TREE_TYPE (TREE_OPERAND (in, 0))))) - in = TREE_OPERAND (in, 0); - - if (TREE_CODE (in) == code - || (! FLOAT_TYPE_P (TREE_TYPE (in)) - /* We can associate addition and subtraction together - (even though the C standard doesn't say so) - for integers because the value is not affected. - For reals, the value might be affected, so we can't. */ - && ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR) - || (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR)))) - { - enum tree_code code = TREE_CODE (TREE_OPERAND (in, 0)); - if (code == INTEGER_CST) - { - *conp = TREE_OPERAND (in, 0); - *varp = TREE_OPERAND (in, 1); - if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) - && TREE_TYPE (*varp) != outtype) - *varp = convert (outtype, *varp); - *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; - return 1; - } - if (TREE_CONSTANT (TREE_OPERAND (in, 1))) - { - *conp = TREE_OPERAND (in, 1); - *varp = TREE_OPERAND (in, 0); - *varsignp = 1; - if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) - && TREE_TYPE (*varp) != outtype) - *varp = convert (outtype, *varp); - if (TREE_CODE (in) == MINUS_EXPR) - { - /* If operation is subtraction and constant is second, - must negate it to get an additive constant. - And this cannot be done unless it is a manifest constant. - It could also be the address of a static variable. - We cannot negate that, so give up. */ - if (TREE_CODE (*conp) == INTEGER_CST) - /* Subtracting from integer_zero_node loses for long long. */ - *conp = fold (build1 (NEGATE_EXPR, TREE_TYPE (*conp), *conp)); - else - return 0; - } - return 1; - } - if (TREE_CONSTANT (TREE_OPERAND (in, 0))) - { - *conp = TREE_OPERAND (in, 0); - *varp = TREE_OPERAND (in, 1); - if (TYPE_MODE (TREE_TYPE (*varp)) != TYPE_MODE (outtype) - && TREE_TYPE (*varp) != outtype) - *varp = convert (outtype, *varp); - *varsignp = (TREE_CODE (in) == MINUS_EXPR) ? -1 : 1; - return 1; - } - } - return 0; -} - -/* Combine two constants ARG1 and ARG2 under operation CODE - to produce a new constant. - We assume ARG1 and ARG2 have the same data type, - or at least are the same kind of constant and the same machine mode. - - If NOTRUNC is nonzero, do not truncate the result to fit the data type. */ - -static tree -const_binop (code, arg1, arg2, notrunc) - enum tree_code code; - register tree arg1, arg2; - int notrunc; -{ - STRIP_NOPS (arg1); STRIP_NOPS (arg2); - - if (TREE_CODE (arg1) == INTEGER_CST) - { - register HOST_WIDE_INT int1l = TREE_INT_CST_LOW (arg1); - register HOST_WIDE_INT int1h = TREE_INT_CST_HIGH (arg1); - HOST_WIDE_INT int2l = TREE_INT_CST_LOW (arg2); - HOST_WIDE_INT int2h = TREE_INT_CST_HIGH (arg2); - HOST_WIDE_INT low, hi; - HOST_WIDE_INT garbagel, garbageh; - register tree t; - int uns = TREE_UNSIGNED (TREE_TYPE (arg1)); - int overflow = 0; - int no_overflow = 0; - - switch (code) - { - case BIT_IOR_EXPR: - low = int1l | int2l, hi = int1h | int2h; - break; - - case BIT_XOR_EXPR: - low = int1l ^ int2l, hi = int1h ^ int2h; - break; - - case BIT_AND_EXPR: - low = int1l & int2l, hi = int1h & int2h; - break; - - case BIT_ANDTC_EXPR: - low = int1l & ~int2l, hi = int1h & ~int2h; - break; - - case RSHIFT_EXPR: - int2l = - int2l; - case LSHIFT_EXPR: - /* It's unclear from the C standard whether shifts can overflow. - The following code ignores overflow; perhaps a C standard - interpretation ruling is needed. */ - lshift_double (int1l, int1h, int2l, - TYPE_PRECISION (TREE_TYPE (arg1)), - &low, &hi, - !uns); - no_overflow = 1; - break; - - case RROTATE_EXPR: - int2l = - int2l; - case LROTATE_EXPR: - lrotate_double (int1l, int1h, int2l, - TYPE_PRECISION (TREE_TYPE (arg1)), - &low, &hi); - break; - - case PLUS_EXPR: - overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi); - break; - - case MINUS_EXPR: - neg_double (int2l, int2h, &low, &hi); - add_double (int1l, int1h, low, hi, &low, &hi); - overflow = overflow_sum_sign (hi, int2h, int1h); - break; - - case MULT_EXPR: - overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi); - break; - - case TRUNC_DIV_EXPR: - case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR: - case EXACT_DIV_EXPR: - /* This is a shortcut for a common special case. */ - if (int2h == 0 && int2l > 0 - && ! TREE_CONSTANT_OVERFLOW (arg1) - && ! TREE_CONSTANT_OVERFLOW (arg2) - && int1h == 0 && int1l >= 0) - { - if (code == CEIL_DIV_EXPR) - int1l += int2l - 1; - low = int1l / int2l, hi = 0; - break; - } - - /* ... fall through ... */ - - case ROUND_DIV_EXPR: - if (int2h == 0 && int2l == 1) - { - low = int1l, hi = int1h; - break; - } - if (int1l == int2l && int1h == int2h - && ! (int1l == 0 && int1h == 0)) - { - low = 1, hi = 0; - break; - } - overflow = div_and_round_double (code, uns, - int1l, int1h, int2l, int2h, - &low, &hi, &garbagel, &garbageh); - break; - - case TRUNC_MOD_EXPR: - case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR: - /* This is a shortcut for a common special case. */ - if (int2h == 0 && int2l > 0 - && ! TREE_CONSTANT_OVERFLOW (arg1) - && ! TREE_CONSTANT_OVERFLOW (arg2) - && int1h == 0 && int1l >= 0) - { - if (code == CEIL_MOD_EXPR) - int1l += int2l - 1; - low = int1l % int2l, hi = 0; - break; - } - - /* ... fall through ... */ - - case ROUND_MOD_EXPR: - overflow = div_and_round_double (code, uns, - int1l, int1h, int2l, int2h, - &garbagel, &garbageh, &low, &hi); - break; - - case MIN_EXPR: - case MAX_EXPR: - if (uns) - { - low = (((unsigned HOST_WIDE_INT) int1h - < (unsigned HOST_WIDE_INT) int2h) - || (((unsigned HOST_WIDE_INT) int1h - == (unsigned HOST_WIDE_INT) int2h) - && ((unsigned HOST_WIDE_INT) int1l - < (unsigned HOST_WIDE_INT) int2l))); - } - else - { - low = ((int1h < int2h) - || ((int1h == int2h) - && ((unsigned HOST_WIDE_INT) int1l - < (unsigned HOST_WIDE_INT) int2l))); - } - if (low == (code == MIN_EXPR)) - low = int1l, hi = int1h; - else - low = int2l, hi = int2h; - break; - - default: - abort (); - } - got_it: - if (TREE_TYPE (arg1) == sizetype && hi == 0 - && low >= 0 && low <= TREE_INT_CST_LOW (TYPE_MAX_VALUE (sizetype)) - && ! overflow - && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2)) - t = size_int (low); - else - { - t = build_int_2 (low, hi); - TREE_TYPE (t) = TREE_TYPE (arg1); - } - - TREE_OVERFLOW (t) - = ((notrunc ? !uns && overflow - : force_fit_type (t, overflow && !uns) && ! no_overflow) - | TREE_OVERFLOW (arg1) - | TREE_OVERFLOW (arg2)); - TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t) - | TREE_CONSTANT_OVERFLOW (arg1) - | TREE_CONSTANT_OVERFLOW (arg2)); - return t; - } -#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) - if (TREE_CODE (arg1) == REAL_CST) - { - REAL_VALUE_TYPE d1; - REAL_VALUE_TYPE d2; - int overflow = 0; - REAL_VALUE_TYPE value; - tree t; - - d1 = TREE_REAL_CST (arg1); - d2 = TREE_REAL_CST (arg2); - - /* If either operand is a NaN, just return it. Otherwise, set up - for floating-point trap; we return an overflow. */ - if (REAL_VALUE_ISNAN (d1)) - return arg1; - else if (REAL_VALUE_ISNAN (d2)) - return arg2; - else if (setjmp (float_error)) - { - t = copy_node (arg1); - overflow = 1; - goto got_float; - } - - set_float_handler (float_error); - -#ifdef REAL_ARITHMETIC - REAL_ARITHMETIC (value, code, d1, d2); -#else - switch (code) - { - case PLUS_EXPR: - value = d1 + d2; - break; - - case MINUS_EXPR: - value = d1 - d2; - break; - - case MULT_EXPR: - value = d1 * d2; - break; - - case RDIV_EXPR: -#ifndef REAL_INFINITY - if (d2 == 0) - abort (); -#endif - - value = d1 / d2; - break; - - case MIN_EXPR: - value = MIN (d1, d2); - break; - - case MAX_EXPR: - value = MAX (d1, d2); - break; - - default: - abort (); - } -#endif /* no REAL_ARITHMETIC */ - t = build_real (TREE_TYPE (arg1), - real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)), value)); - got_float: - set_float_handler (NULL_PTR); - - TREE_OVERFLOW (t) - = (force_fit_type (t, overflow) - | TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2)); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) - | TREE_CONSTANT_OVERFLOW (arg1) - | TREE_CONSTANT_OVERFLOW (arg2); - return t; - } -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - if (TREE_CODE (arg1) == COMPLEX_CST) - { - register tree type = TREE_TYPE (arg1); - register tree r1 = TREE_REALPART (arg1); - register tree i1 = TREE_IMAGPART (arg1); - register tree r2 = TREE_REALPART (arg2); - register tree i2 = TREE_IMAGPART (arg2); - register tree t; - - switch (code) - { - case PLUS_EXPR: - t = build_complex (type, - const_binop (PLUS_EXPR, r1, r2, notrunc), - const_binop (PLUS_EXPR, i1, i2, notrunc)); - break; - - case MINUS_EXPR: - t = build_complex (type, - const_binop (MINUS_EXPR, r1, r2, notrunc), - const_binop (MINUS_EXPR, i1, i2, notrunc)); - break; - - case MULT_EXPR: - t = build_complex (type, - const_binop (MINUS_EXPR, - const_binop (MULT_EXPR, - r1, r2, notrunc), - const_binop (MULT_EXPR, - i1, i2, notrunc), - notrunc), - const_binop (PLUS_EXPR, - const_binop (MULT_EXPR, - r1, i2, notrunc), - const_binop (MULT_EXPR, - i1, r2, notrunc), - notrunc)); - break; - - case RDIV_EXPR: - { - register tree magsquared - = const_binop (PLUS_EXPR, - const_binop (MULT_EXPR, r2, r2, notrunc), - const_binop (MULT_EXPR, i2, i2, notrunc), - notrunc); - - t = build_complex (type, - const_binop - (INTEGRAL_TYPE_P (TREE_TYPE (r1)) - ? TRUNC_DIV_EXPR : RDIV_EXPR, - const_binop (PLUS_EXPR, - const_binop (MULT_EXPR, r1, r2, - notrunc), - const_binop (MULT_EXPR, i1, i2, - notrunc), - notrunc), - magsquared, notrunc), - const_binop - (INTEGRAL_TYPE_P (TREE_TYPE (r1)) - ? TRUNC_DIV_EXPR : RDIV_EXPR, - const_binop (MINUS_EXPR, - const_binop (MULT_EXPR, i1, r2, - notrunc), - const_binop (MULT_EXPR, r1, i2, - notrunc), - notrunc), - magsquared, notrunc)); - } - break; - - default: - abort (); - } - return t; - } - return 0; -} - -/* Return an INTEGER_CST with value V and type from `sizetype'. */ - -tree -size_int (number) - unsigned HOST_WIDE_INT number; -{ - register tree t; - /* Type-size nodes already made for small sizes. */ - static tree size_table[2*HOST_BITS_PER_WIDE_INT + 1]; - - if (number < 2*HOST_BITS_PER_WIDE_INT + 1 - && size_table[number] != 0) - return size_table[number]; - if (number < 2*HOST_BITS_PER_WIDE_INT + 1) - { - push_obstacks_nochange (); - /* Make this a permanent node. */ - end_temporary_allocation (); - t = build_int_2 (number, 0); - TREE_TYPE (t) = sizetype; - size_table[number] = t; - pop_obstacks (); - } - else - { - t = build_int_2 (number, 0); - TREE_TYPE (t) = sizetype; - TREE_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (t) = force_fit_type (t, 0); - } - return t; -} - -/* Combine operands OP1 and OP2 with arithmetic operation CODE. - CODE is a tree code. Data type is taken from `sizetype', - If the operands are constant, so is the result. */ - -tree -size_binop (code, arg0, arg1) - enum tree_code code; - tree arg0, arg1; -{ - /* Handle the special case of two integer constants faster. */ - if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) - { - /* And some specific cases even faster than that. */ - if (code == PLUS_EXPR && integer_zerop (arg0)) - return arg1; - else if ((code == MINUS_EXPR || code == PLUS_EXPR) - && integer_zerop (arg1)) - return arg0; - else if (code == MULT_EXPR && integer_onep (arg0)) - return arg1; - - /* Handle general case of two integer constants. */ - return const_binop (code, arg0, arg1, 0); - } - - if (arg0 == error_mark_node || arg1 == error_mark_node) - return error_mark_node; - - return fold (build (code, sizetype, arg0, arg1)); -} - -/* Given T, a tree representing type conversion of ARG1, a constant, - return a constant tree representing the result of conversion. */ - -static tree -fold_convert (t, arg1) - register tree t; - register tree arg1; -{ - register tree type = TREE_TYPE (t); - int overflow = 0; - - if (TREE_CODE (type) == POINTER_TYPE || INTEGRAL_TYPE_P (type)) - { - if (TREE_CODE (arg1) == INTEGER_CST) - { - /* If we would build a constant wider than GCC supports, - leave the conversion unfolded. */ - if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT) - return t; - - /* Given an integer constant, make new constant with new type, - appropriately sign-extended or truncated. */ - t = build_int_2 (TREE_INT_CST_LOW (arg1), - TREE_INT_CST_HIGH (arg1)); - TREE_TYPE (t) = type; - /* Indicate an overflow if (1) ARG1 already overflowed, - or (2) force_fit_type indicates an overflow. - Tell force_fit_type that an overflow has already occurred - if ARG1 is a too-large unsigned value and T is signed. */ - TREE_OVERFLOW (t) - = (TREE_OVERFLOW (arg1) - | force_fit_type (t, - (TREE_INT_CST_HIGH (arg1) < 0 - & (TREE_UNSIGNED (type) - < TREE_UNSIGNED (TREE_TYPE (arg1)))))); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1); - } -#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) - else if (TREE_CODE (arg1) == REAL_CST) - { - /* Don't initialize these, use assignments. - Initialized local aggregates don't work on old compilers. */ - REAL_VALUE_TYPE x; - REAL_VALUE_TYPE l; - REAL_VALUE_TYPE u; - tree type1 = TREE_TYPE (arg1); - - x = TREE_REAL_CST (arg1); - l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type)); - u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type)); - /* See if X will be in range after truncation towards 0. - To compensate for truncation, move the bounds away from 0, - but reject if X exactly equals the adjusted bounds. */ -#ifdef REAL_ARITHMETIC - REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1); - REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1); -#else - l--; - u++; -#endif - /* If X is a NaN, use zero instead and show we have an overflow. - Otherwise, range check. */ - if (REAL_VALUE_ISNAN (x)) - overflow = 1, x = dconst0; - else if (! (REAL_VALUES_LESS (l, x) && REAL_VALUES_LESS (x, u))) - overflow = 1; - -#ifndef REAL_ARITHMETIC - { - HOST_WIDE_INT low, high; - HOST_WIDE_INT half_word - = (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2); - - if (x < 0) - x = -x; - - high = (HOST_WIDE_INT) (x / half_word / half_word); - x -= (REAL_VALUE_TYPE) high * half_word * half_word; - if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2) - { - low = x - (REAL_VALUE_TYPE) half_word * half_word / 2; - low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1); - } - else - low = (HOST_WIDE_INT) x; - if (TREE_REAL_CST (arg1) < 0) - neg_double (low, high, &low, &high); - t = build_int_2 (low, high); - } -#else - { - HOST_WIDE_INT low, high; - REAL_VALUE_TO_INT (&low, &high, x); - t = build_int_2 (low, high); - } -#endif - TREE_TYPE (t) = type; - TREE_OVERFLOW (t) - = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1); - } -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - TREE_TYPE (t) = type; - } - else if (TREE_CODE (type) == REAL_TYPE) - { -#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) - if (TREE_CODE (arg1) == INTEGER_CST) - return build_real_from_int_cst (type, arg1); -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - if (TREE_CODE (arg1) == REAL_CST) - { - if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1))) - { - t = arg1; - TREE_TYPE (arg1) = type; - return t; - } - else if (setjmp (float_error)) - { - overflow = 1; - t = copy_node (arg1); - goto got_it; - } - set_float_handler (float_error); - - t = build_real (type, real_value_truncate (TYPE_MODE (type), - TREE_REAL_CST (arg1))); - set_float_handler (NULL_PTR); - - got_it: - TREE_OVERFLOW (t) - = TREE_OVERFLOW (arg1) | force_fit_type (t, overflow); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1); - return t; - } - } - TREE_CONSTANT (t) = 1; - return t; -} - -/* Return an expr equal to X but certainly not valid as an lvalue. - Also make sure it is not valid as an null pointer constant. */ - -tree -non_lvalue (x) - tree x; -{ - tree result; - - /* These things are certainly not lvalues. */ - if (TREE_CODE (x) == NON_LVALUE_EXPR - || TREE_CODE (x) == INTEGER_CST - || TREE_CODE (x) == REAL_CST - || TREE_CODE (x) == STRING_CST - || TREE_CODE (x) == ADDR_EXPR) - { - if (TREE_CODE (x) == INTEGER_CST && integer_zerop (x)) - { - /* Use NOP_EXPR instead of NON_LVALUE_EXPR - so convert_for_assignment won't strip it. - This is so this 0 won't be treated as a null pointer constant. */ - result = build1 (NOP_EXPR, TREE_TYPE (x), x); - TREE_CONSTANT (result) = TREE_CONSTANT (x); - return result; - } - return x; - } - - result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x); - TREE_CONSTANT (result) = TREE_CONSTANT (x); - return result; -} - -/* Nonzero means lvalues are limited to those valid in pedantic ANSI C. - Zero means allow extended lvalues. */ - -int pedantic_lvalues; - -/* When pedantic, return an expr equal to X but certainly not valid as a - pedantic lvalue. Otherwise, return X. */ - -tree -pedantic_non_lvalue (x) - tree x; -{ - if (pedantic_lvalues) - return non_lvalue (x); - else - return x; -} - -/* Given a tree comparison code, return the code that is the logical inverse - of the given code. It is not safe to do this for floating-point - comparisons, except for NE_EXPR and EQ_EXPR. */ - -static enum tree_code -invert_tree_comparison (code) - enum tree_code code; -{ - switch (code) - { - case EQ_EXPR: - return NE_EXPR; - case NE_EXPR: - return EQ_EXPR; - case GT_EXPR: - return LE_EXPR; - case GE_EXPR: - return LT_EXPR; - case LT_EXPR: - return GE_EXPR; - case LE_EXPR: - return GT_EXPR; - default: - abort (); - } -} - -/* Similar, but return the comparison that results if the operands are - swapped. This is safe for floating-point. */ - -static enum tree_code -swap_tree_comparison (code) - enum tree_code code; -{ - switch (code) - { - case EQ_EXPR: - case NE_EXPR: - return code; - case GT_EXPR: - return LT_EXPR; - case GE_EXPR: - return LE_EXPR; - case LT_EXPR: - return GT_EXPR; - case LE_EXPR: - return GE_EXPR; - default: - abort (); - } -} - -/* Return nonzero if CODE is a tree code that represents a truth value. */ - -static int -truth_value_p (code) - enum tree_code code; -{ - return (TREE_CODE_CLASS (code) == '<' - || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR - || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR - || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR); -} - -/* Return nonzero if two operands are necessarily equal. - If ONLY_CONST is non-zero, only return non-zero for constants. - This function tests whether the operands are indistinguishable; - it does not test whether they are equal using C's == operation. - The distinction is important for IEEE floating point, because - (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and - (2) two NaNs may be indistinguishable, but NaN!=NaN. */ - -int -operand_equal_p (arg0, arg1, only_const) - tree arg0, arg1; - int only_const; -{ - /* If both types don't have the same signedness, then we can't consider - them equal. We must check this before the STRIP_NOPS calls - because they may change the signedness of the arguments. */ - if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1))) - return 0; - - STRIP_NOPS (arg0); - STRIP_NOPS (arg1); - - if (TREE_CODE (arg0) != TREE_CODE (arg1) - /* This is needed for conversions and for COMPONENT_REF. - Might as well play it safe and always test this. */ - || TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1))) - return 0; - - /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal. - We don't care about side effects in that case because the SAVE_EXPR - takes care of that for us. In all other cases, two expressions are - equal if they have no side effects. If we have two identical - expressions with side effects that should be treated the same due - to the only side effects being identical SAVE_EXPR's, that will - be detected in the recursive calls below. */ - if (arg0 == arg1 && ! only_const - && (TREE_CODE (arg0) == SAVE_EXPR - || (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1)))) - return 1; - - /* Next handle constant cases, those for which we can return 1 even - if ONLY_CONST is set. */ - if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1)) - switch (TREE_CODE (arg0)) - { - case INTEGER_CST: - return (TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1) - && TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1)); - - case REAL_CST: - return REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), TREE_REAL_CST (arg1)); - - case COMPLEX_CST: - return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1), - only_const) - && operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1), - only_const)); - - case STRING_CST: - return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1) - && ! strncmp (TREE_STRING_POINTER (arg0), - TREE_STRING_POINTER (arg1), - TREE_STRING_LENGTH (arg0))); - - case ADDR_EXPR: - return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), - 0); - } - - if (only_const) - return 0; - - switch (TREE_CODE_CLASS (TREE_CODE (arg0))) - { - case '1': - /* Two conversions are equal only if signedness and modes match. */ - if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR) - && (TREE_UNSIGNED (TREE_TYPE (arg0)) - != TREE_UNSIGNED (TREE_TYPE (arg1)))) - return 0; - - return operand_equal_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0), 0); - - case '<': - case '2': - if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0) - && operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), - 0)) - return 1; - - /* For commutative ops, allow the other order. */ - return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR - || TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR - || TREE_CODE (arg0) == BIT_IOR_EXPR - || TREE_CODE (arg0) == BIT_XOR_EXPR - || TREE_CODE (arg0) == BIT_AND_EXPR - || TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR) - && operand_equal_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 1), 0) - && operand_equal_p (TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 0), 0)); - - case 'r': - switch (TREE_CODE (arg0)) - { - case INDIRECT_REF: - return operand_equal_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0), 0); - - case COMPONENT_REF: - case ARRAY_REF: - return (operand_equal_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0), 0) - && operand_equal_p (TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 1), 0)); - - case BIT_FIELD_REF: - return (operand_equal_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0), 0) - && operand_equal_p (TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 1), 0) - && operand_equal_p (TREE_OPERAND (arg0, 2), - TREE_OPERAND (arg1, 2), 0)); - } - break; - } - - return 0; -} - -/* Similar to operand_equal_p, but see if ARG0 might have been made by - shorten_compare from ARG1 when ARG1 was being compared with OTHER. - - When in doubt, return 0. */ - -static int -operand_equal_for_comparison_p (arg0, arg1, other) - tree arg0, arg1; - tree other; -{ - int unsignedp1, unsignedpo; - tree primarg1, primother; - unsigned correct_width; - - if (operand_equal_p (arg0, arg1, 0)) - return 1; - - if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0)) - || ! INTEGRAL_TYPE_P (TREE_TYPE (arg1))) - return 0; - - /* Duplicate what shorten_compare does to ARG1 and see if that gives the - actual comparison operand, ARG0. - - First throw away any conversions to wider types - already present in the operands. */ - - primarg1 = get_narrower (arg1, &unsignedp1); - primother = get_narrower (other, &unsignedpo); - - correct_width = TYPE_PRECISION (TREE_TYPE (arg1)); - if (unsignedp1 == unsignedpo - && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width - && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width) - { - tree type = TREE_TYPE (arg0); - - /* Make sure shorter operand is extended the right way - to match the longer operand. */ - primarg1 = convert (signed_or_unsigned_type (unsignedp1, - TREE_TYPE (primarg1)), - primarg1); - - if (operand_equal_p (arg0, convert (type, primarg1), 0)) - return 1; - } - - return 0; -} - -/* See if ARG is an expression that is either a comparison or is performing - arithmetic on comparisons. The comparisons must only be comparing - two different values, which will be stored in *CVAL1 and *CVAL2; if - they are non-zero it means that some operands have already been found. - No variables may be used anywhere else in the expression except in the - comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around - the expression and save_expr needs to be called with CVAL1 and CVAL2. - - If this is true, return 1. Otherwise, return zero. */ - -static int -twoval_comparison_p (arg, cval1, cval2, save_p) - tree arg; - tree *cval1, *cval2; - int *save_p; -{ - enum tree_code code = TREE_CODE (arg); - char class = TREE_CODE_CLASS (code); - - /* We can handle some of the 'e' cases here. */ - if (class == 'e' && code == TRUTH_NOT_EXPR) - class = '1'; - else if (class == 'e' - && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR - || code == COMPOUND_EXPR)) - class = '2'; - - /* ??? Disable this since the SAVE_EXPR might already be in use outside - the expression. There may be no way to make this work, but it needs - to be looked at again for 2.6. */ -#if 0 - else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0) - { - /* If we've already found a CVAL1 or CVAL2, this expression is - two complex to handle. */ - if (*cval1 || *cval2) - return 0; - - class = '1'; - *save_p = 1; - } -#endif - - switch (class) - { - case '1': - return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p); - - case '2': - return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p) - && twoval_comparison_p (TREE_OPERAND (arg, 1), - cval1, cval2, save_p)); - - case 'c': - return 1; - - case 'e': - if (code == COND_EXPR) - return (twoval_comparison_p (TREE_OPERAND (arg, 0), - cval1, cval2, save_p) - && twoval_comparison_p (TREE_OPERAND (arg, 1), - cval1, cval2, save_p) - && twoval_comparison_p (TREE_OPERAND (arg, 2), - cval1, cval2, save_p)); - return 0; - - case '<': - /* First see if we can handle the first operand, then the second. For - the second operand, we know *CVAL1 can't be zero. It must be that - one side of the comparison is each of the values; test for the - case where this isn't true by failing if the two operands - are the same. */ - - if (operand_equal_p (TREE_OPERAND (arg, 0), - TREE_OPERAND (arg, 1), 0)) - return 0; - - if (*cval1 == 0) - *cval1 = TREE_OPERAND (arg, 0); - else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0)) - ; - else if (*cval2 == 0) - *cval2 = TREE_OPERAND (arg, 0); - else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0)) - ; - else - return 0; - - if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0)) - ; - else if (*cval2 == 0) - *cval2 = TREE_OPERAND (arg, 1); - else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0)) - ; - else - return 0; - - return 1; - } - - return 0; -} - -/* ARG is a tree that is known to contain just arithmetic operations and - comparisons. Evaluate the operations in the tree substituting NEW0 for - any occurrence of OLD0 as an operand of a comparison and likewise for - NEW1 and OLD1. */ - -static tree -eval_subst (arg, old0, new0, old1, new1) - tree arg; - tree old0, new0, old1, new1; -{ - tree type = TREE_TYPE (arg); - enum tree_code code = TREE_CODE (arg); - char class = TREE_CODE_CLASS (code); - - /* We can handle some of the 'e' cases here. */ - if (class == 'e' && code == TRUTH_NOT_EXPR) - class = '1'; - else if (class == 'e' - && (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)) - class = '2'; - - switch (class) - { - case '1': - return fold (build1 (code, type, - eval_subst (TREE_OPERAND (arg, 0), - old0, new0, old1, new1))); - - case '2': - return fold (build (code, type, - eval_subst (TREE_OPERAND (arg, 0), - old0, new0, old1, new1), - eval_subst (TREE_OPERAND (arg, 1), - old0, new0, old1, new1))); - - case 'e': - switch (code) - { - case SAVE_EXPR: - return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1); - - case COMPOUND_EXPR: - return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1); - - case COND_EXPR: - return fold (build (code, type, - eval_subst (TREE_OPERAND (arg, 0), - old0, new0, old1, new1), - eval_subst (TREE_OPERAND (arg, 1), - old0, new0, old1, new1), - eval_subst (TREE_OPERAND (arg, 2), - old0, new0, old1, new1))); - } - - case '<': - { - tree arg0 = TREE_OPERAND (arg, 0); - tree arg1 = TREE_OPERAND (arg, 1); - - /* We need to check both for exact equality and tree equality. The - former will be true if the operand has a side-effect. In that - case, we know the operand occurred exactly once. */ - - if (arg0 == old0 || operand_equal_p (arg0, old0, 0)) - arg0 = new0; - else if (arg0 == old1 || operand_equal_p (arg0, old1, 0)) - arg0 = new1; - - if (arg1 == old0 || operand_equal_p (arg1, old0, 0)) - arg1 = new0; - else if (arg1 == old1 || operand_equal_p (arg1, old1, 0)) - arg1 = new1; - - return fold (build (code, type, arg0, arg1)); - } - } - - return arg; -} - -/* Return a tree for the case when the result of an expression is RESULT - converted to TYPE and OMITTED was previously an operand of the expression - but is now not needed (e.g., we folded OMITTED * 0). - - If OMITTED has side effects, we must evaluate it. Otherwise, just do - the conversion of RESULT to TYPE. */ - -static tree -omit_one_operand (type, result, omitted) - tree type, result, omitted; -{ - tree t = convert (type, result); - - if (TREE_SIDE_EFFECTS (omitted)) - return build (COMPOUND_EXPR, type, omitted, t); - - return non_lvalue (t); -} - -/* Similar, but call pedantic_non_lvalue instead of non_lvalue. */ - -static tree -pedantic_omit_one_operand (type, result, omitted) - tree type, result, omitted; -{ - tree t = convert (type, result); - - if (TREE_SIDE_EFFECTS (omitted)) - return build (COMPOUND_EXPR, type, omitted, t); - - return pedantic_non_lvalue (t); -} - - - -/* Return a simplified tree node for the truth-negation of ARG. This - never alters ARG itself. We assume that ARG is an operation that - returns a truth value (0 or 1). */ - -tree -invert_truthvalue (arg) - tree arg; -{ - tree type = TREE_TYPE (arg); - enum tree_code code = TREE_CODE (arg); - - if (code == ERROR_MARK) - return arg; - - /* If this is a comparison, we can simply invert it, except for - floating-point non-equality comparisons, in which case we just - enclose a TRUTH_NOT_EXPR around what we have. */ - - if (TREE_CODE_CLASS (code) == '<') - { - if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0))) - && code != NE_EXPR && code != EQ_EXPR) - return build1 (TRUTH_NOT_EXPR, type, arg); - else - return build (invert_tree_comparison (code), type, - TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1)); - } - - switch (code) - { - case INTEGER_CST: - return convert (type, build_int_2 (TREE_INT_CST_LOW (arg) == 0 - && TREE_INT_CST_HIGH (arg) == 0, 0)); - - case TRUTH_AND_EXPR: - return build (TRUTH_OR_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0)), - invert_truthvalue (TREE_OPERAND (arg, 1))); - - case TRUTH_OR_EXPR: - return build (TRUTH_AND_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0)), - invert_truthvalue (TREE_OPERAND (arg, 1))); - - case TRUTH_XOR_EXPR: - /* Here we can invert either operand. We invert the first operand - unless the second operand is a TRUTH_NOT_EXPR in which case our - result is the XOR of the first operand with the inside of the - negation of the second operand. */ - - if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR) - return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0), - TREE_OPERAND (TREE_OPERAND (arg, 1), 0)); - else - return build (TRUTH_XOR_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0)), - TREE_OPERAND (arg, 1)); - - case TRUTH_ANDIF_EXPR: - return build (TRUTH_ORIF_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0)), - invert_truthvalue (TREE_OPERAND (arg, 1))); - - case TRUTH_ORIF_EXPR: - return build (TRUTH_ANDIF_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0)), - invert_truthvalue (TREE_OPERAND (arg, 1))); - - case TRUTH_NOT_EXPR: - return TREE_OPERAND (arg, 0); - - case COND_EXPR: - return build (COND_EXPR, type, TREE_OPERAND (arg, 0), - invert_truthvalue (TREE_OPERAND (arg, 1)), - invert_truthvalue (TREE_OPERAND (arg, 2))); - - case COMPOUND_EXPR: - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0), - invert_truthvalue (TREE_OPERAND (arg, 1))); - - case NON_LVALUE_EXPR: - return invert_truthvalue (TREE_OPERAND (arg, 0)); - - case NOP_EXPR: - case CONVERT_EXPR: - case FLOAT_EXPR: - return build1 (TREE_CODE (arg), type, - invert_truthvalue (TREE_OPERAND (arg, 0))); - - case BIT_AND_EXPR: - if (!integer_onep (TREE_OPERAND (arg, 1))) - break; - return build (EQ_EXPR, type, arg, convert (type, integer_zero_node)); - - case SAVE_EXPR: - return build1 (TRUTH_NOT_EXPR, type, arg); - - case CLEANUP_POINT_EXPR: - return build1 (CLEANUP_POINT_EXPR, type, - invert_truthvalue (TREE_OPERAND (arg, 0))); - } - if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE) - abort (); - return build1 (TRUTH_NOT_EXPR, type, arg); -} - -/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both - operands are another bit-wise operation with a common input. If so, - distribute the bit operations to save an operation and possibly two if - constants are involved. For example, convert - (A | B) & (A | C) into A | (B & C) - Further simplification will occur if B and C are constants. - - If this optimization cannot be done, 0 will be returned. */ - -static tree -distribute_bit_expr (code, type, arg0, arg1) - enum tree_code code; - tree type; - tree arg0, arg1; -{ - tree common; - tree left, right; - - if (TREE_CODE (arg0) != TREE_CODE (arg1) - || TREE_CODE (arg0) == code - || (TREE_CODE (arg0) != BIT_AND_EXPR - && TREE_CODE (arg0) != BIT_IOR_EXPR)) - return 0; - - if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)) - { - common = TREE_OPERAND (arg0, 0); - left = TREE_OPERAND (arg0, 1); - right = TREE_OPERAND (arg1, 1); - } - else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0)) - { - common = TREE_OPERAND (arg0, 0); - left = TREE_OPERAND (arg0, 1); - right = TREE_OPERAND (arg1, 0); - } - else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0)) - { - common = TREE_OPERAND (arg0, 1); - left = TREE_OPERAND (arg0, 0); - right = TREE_OPERAND (arg1, 1); - } - else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0)) - { - common = TREE_OPERAND (arg0, 1); - left = TREE_OPERAND (arg0, 0); - right = TREE_OPERAND (arg1, 0); - } - else - return 0; - - return fold (build (TREE_CODE (arg0), type, common, - fold (build (code, type, left, right)))); -} - -/* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER - starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */ - -static tree -make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp) - tree inner; - tree type; - int bitsize, bitpos; - int unsignedp; -{ - tree result = build (BIT_FIELD_REF, type, inner, - size_int (bitsize), size_int (bitpos)); - - TREE_UNSIGNED (result) = unsignedp; - - return result; -} - -/* Optimize a bit-field compare. - - There are two cases: First is a compare against a constant and the - second is a comparison of two items where the fields are at the same - bit position relative to the start of a chunk (byte, halfword, word) - large enough to contain it. In these cases we can avoid the shift - implicit in bitfield extractions. - - For constants, we emit a compare of the shifted constant with the - BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being - compared. For two fields at the same position, we do the ANDs with the - similar mask and compare the result of the ANDs. - - CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR. - COMPARE_TYPE is the type of the comparison, and LHS and RHS - are the left and right operands of the comparison, respectively. - - If the optimization described above can be done, we return the resulting - tree. Otherwise we return zero. */ - -static tree -optimize_bit_field_compare (code, compare_type, lhs, rhs) - enum tree_code code; - tree compare_type; - tree lhs, rhs; -{ - int lbitpos, lbitsize, rbitpos, rbitsize; - int lnbitpos, lnbitsize, rnbitpos, rnbitsize; - tree type = TREE_TYPE (lhs); - tree signed_type, unsigned_type; - int const_p = TREE_CODE (rhs) == INTEGER_CST; - enum machine_mode lmode, rmode, lnmode, rnmode; - int lunsignedp, runsignedp; - int lvolatilep = 0, rvolatilep = 0; - int alignment; - tree linner, rinner; - tree mask; - tree offset; - - /* Get all the information about the extractions being done. If the bit size - if the same as the size of the underlying object, we aren't doing an - extraction at all and so can do nothing. */ - linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode, - &lunsignedp, &lvolatilep, &alignment); - if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0 - || offset != 0) - return 0; - - if (!const_p) - { - /* If this is not a constant, we can only do something if bit positions, - sizes, and signedness are the same. */ - rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode, - &runsignedp, &rvolatilep, &alignment); - - if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize - || lunsignedp != runsignedp || offset != 0) - return 0; - } - - /* See if we can find a mode to refer to this field. We should be able to, - but fail if we can't. */ - lnmode = get_best_mode (lbitsize, lbitpos, - TYPE_ALIGN (TREE_TYPE (linner)), word_mode, - lvolatilep); - if (lnmode == VOIDmode) - return 0; - - /* Set signed and unsigned types of the precision of this mode for the - shifts below. */ - signed_type = type_for_mode (lnmode, 0); - unsigned_type = type_for_mode (lnmode, 1); - - if (! const_p) - { - rnmode = get_best_mode (rbitsize, rbitpos, - TYPE_ALIGN (TREE_TYPE (rinner)), word_mode, - rvolatilep); - if (rnmode == VOIDmode) - return 0; - } - - /* Compute the bit position and size for the new reference and our offset - within it. If the new reference is the same size as the original, we - won't optimize anything, so return zero. */ - lnbitsize = GET_MODE_BITSIZE (lnmode); - lnbitpos = lbitpos & ~ (lnbitsize - 1); - lbitpos -= lnbitpos; - if (lnbitsize == lbitsize) - return 0; - - if (! const_p) - { - rnbitsize = GET_MODE_BITSIZE (rnmode); - rnbitpos = rbitpos & ~ (rnbitsize - 1); - rbitpos -= rnbitpos; - if (rnbitsize == rbitsize) - return 0; - } - - if (BYTES_BIG_ENDIAN) - lbitpos = lnbitsize - lbitsize - lbitpos; - - /* Make the mask to be used against the extracted field. */ - mask = build_int_2 (~0, ~0); - TREE_TYPE (mask) = unsigned_type; - force_fit_type (mask, 0); - mask = convert (unsigned_type, mask); - mask = const_binop (LSHIFT_EXPR, mask, size_int (lnbitsize - lbitsize), 0); - mask = const_binop (RSHIFT_EXPR, mask, - size_int (lnbitsize - lbitsize - lbitpos), 0); - - if (! const_p) - /* If not comparing with constant, just rework the comparison - and return. */ - return build (code, compare_type, - build (BIT_AND_EXPR, unsigned_type, - make_bit_field_ref (linner, unsigned_type, - lnbitsize, lnbitpos, 1), - mask), - build (BIT_AND_EXPR, unsigned_type, - make_bit_field_ref (rinner, unsigned_type, - rnbitsize, rnbitpos, 1), - mask)); - - /* Otherwise, we are handling the constant case. See if the constant is too - big for the field. Warn and return a tree of for 0 (false) if so. We do - this not only for its own sake, but to avoid having to test for this - error case below. If we didn't, we might generate wrong code. - - For unsigned fields, the constant shifted right by the field length should - be all zero. For signed fields, the high-order bits should agree with - the sign bit. */ - - if (lunsignedp) - { - if (! integer_zerop (const_binop (RSHIFT_EXPR, - convert (unsigned_type, rhs), - size_int (lbitsize), 0))) - { - warning ("comparison is always %s due to width of bitfield", - code == NE_EXPR ? "one" : "zero"); - return convert (compare_type, - (code == NE_EXPR - ? integer_one_node : integer_zero_node)); - } - } - else - { - tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs), - size_int (lbitsize - 1), 0); - if (! integer_zerop (tem) && ! integer_all_onesp (tem)) - { - warning ("comparison is always %s due to width of bitfield", - code == NE_EXPR ? "one" : "zero"); - return convert (compare_type, - (code == NE_EXPR - ? integer_one_node : integer_zero_node)); - } - } - - /* Single-bit compares should always be against zero. */ - if (lbitsize == 1 && ! integer_zerop (rhs)) - { - code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR; - rhs = convert (type, integer_zero_node); - } - - /* Make a new bitfield reference, shift the constant over the - appropriate number of bits and mask it with the computed mask - (in case this was a signed field). If we changed it, make a new one. */ - lhs = make_bit_field_ref (linner, unsigned_type, lnbitsize, lnbitpos, 1); - if (lvolatilep) - { - TREE_SIDE_EFFECTS (lhs) = 1; - TREE_THIS_VOLATILE (lhs) = 1; - } - - rhs = fold (const_binop (BIT_AND_EXPR, - const_binop (LSHIFT_EXPR, - convert (unsigned_type, rhs), - size_int (lbitpos), 0), - mask, 0)); - - return build (code, compare_type, - build (BIT_AND_EXPR, unsigned_type, lhs, mask), - rhs); -} - -/* Subroutine for fold_truthop: decode a field reference. - - If EXP is a comparison reference, we return the innermost reference. - - *PBITSIZE is set to the number of bits in the reference, *PBITPOS is - set to the starting bit number. - - If the innermost field can be completely contained in a mode-sized - unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode. - - *PVOLATILEP is set to 1 if the any expression encountered is volatile; - otherwise it is not changed. - - *PUNSIGNEDP is set to the signedness of the field. - - *PMASK is set to the mask used. This is either contained in a - BIT_AND_EXPR or derived from the width of the field. - - *PAND_MASK is set the the mask found in a BIT_AND_EXPR, if any. - - Return 0 if this is not a component reference or is one that we can't - do anything with. */ - -static tree -decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp, - pvolatilep, pmask, pand_mask) - tree exp; - int *pbitsize, *pbitpos; - enum machine_mode *pmode; - int *punsignedp, *pvolatilep; - tree *pmask; - tree *pand_mask; -{ - tree and_mask = 0; - tree mask, inner, offset; - tree unsigned_type; - int precision; - int alignment; - - /* All the optimizations using this function assume integer fields. - There are problems with FP fields since the type_for_size call - below can fail for, e.g., XFmode. */ - if (! INTEGRAL_TYPE_P (TREE_TYPE (exp))) - return 0; - - STRIP_NOPS (exp); - - if (TREE_CODE (exp) == BIT_AND_EXPR) - { - and_mask = TREE_OPERAND (exp, 1); - exp = TREE_OPERAND (exp, 0); - STRIP_NOPS (exp); STRIP_NOPS (and_mask); - if (TREE_CODE (and_mask) != INTEGER_CST) - return 0; - } - - - inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode, - punsignedp, pvolatilep, &alignment); - if ((inner == exp && and_mask == 0) - || *pbitsize < 0 || offset != 0) - return 0; - - /* Compute the mask to access the bitfield. */ - unsigned_type = type_for_size (*pbitsize, 1); - precision = TYPE_PRECISION (unsigned_type); - - mask = build_int_2 (~0, ~0); - TREE_TYPE (mask) = unsigned_type; - force_fit_type (mask, 0); - mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); - mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0); - - /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */ - if (and_mask != 0) - mask = fold (build (BIT_AND_EXPR, unsigned_type, - convert (unsigned_type, and_mask), mask)); - - *pmask = mask; - *pand_mask = and_mask; - return inner; -} - -/* Return non-zero if MASK represents a mask of SIZE ones in the low-order - bit positions. */ - -static int -all_ones_mask_p (mask, size) - tree mask; - int size; -{ - tree type = TREE_TYPE (mask); - int precision = TYPE_PRECISION (type); - tree tmask; - - tmask = build_int_2 (~0, ~0); - TREE_TYPE (tmask) = signed_type (type); - force_fit_type (tmask, 0); - return - tree_int_cst_equal (mask, - const_binop (RSHIFT_EXPR, - const_binop (LSHIFT_EXPR, tmask, - size_int (precision - size), - 0), - size_int (precision - size), 0)); -} - -/* Subroutine for fold_truthop: determine if an operand is simple enough - to be evaluated unconditionally. */ - -static int -simple_operand_p (exp) - tree exp; -{ - /* Strip any conversions that don't change the machine mode. */ - while ((TREE_CODE (exp) == NOP_EXPR - || TREE_CODE (exp) == CONVERT_EXPR) - && (TYPE_MODE (TREE_TYPE (exp)) - == TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0))))) - exp = TREE_OPERAND (exp, 0); - - return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c' - || (TREE_CODE_CLASS (TREE_CODE (exp)) == 'd' - && ! TREE_ADDRESSABLE (exp) - && ! TREE_THIS_VOLATILE (exp) - && ! DECL_NONLOCAL (exp) - /* Don't regard global variables as simple. They may be - allocated in ways unknown to the compiler (shared memory, - #pragma weak, etc). */ - && ! TREE_PUBLIC (exp) - && ! DECL_EXTERNAL (exp) - /* Loading a static variable is unduly expensive, but global - registers aren't expensive. */ - && (! TREE_STATIC (exp) || DECL_REGISTER (exp)))); -} - -/* The following functions are subroutines to fold_range_test and allow it to - try to change a logical combination of comparisons into a range test. - - For example, both - X == 2 && X == 3 && X == 4 && X == 5 - and - X >= 2 && X <= 5 - are converted to - (unsigned) (X - 2) <= 3 - - We decribe each set of comparisons as being either inside or outside - a range, using a variable named like IN_P, and then describe the - range with a lower and upper bound. If one of the bounds is omitted, - it represents either the highest or lowest value of the type. - - In the comments below, we represent a range by two numbers in brackets - preceeded by a "+" to designate being inside that range, or a "-" to - designate being outside that range, so the condition can be inverted by - flipping the prefix. An omitted bound is represented by a "-". For - example, "- [-, 10]" means being outside the range starting at the lowest - possible value and ending at 10, in other words, being greater than 10. - The range "+ [-, -]" is always true and hence the range "- [-, -]" is - always false. - - We set up things so that the missing bounds are handled in a consistent - manner so neither a missing bound nor "true" and "false" need to be - handled using a special case. */ - -/* Return the result of applying CODE to ARG0 and ARG1, but handle the case - of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P - and UPPER1_P are nonzero if the respective argument is an upper bound - and zero for a lower. TYPE, if nonzero, is the type of the result; it - must be specified for a comparison. ARG1 will be converted to ARG0's - type if both are specified. */ - -static tree -range_binop (code, type, arg0, upper0_p, arg1, upper1_p) - enum tree_code code; - tree type; - tree arg0, arg1; - int upper0_p, upper1_p; -{ - tree tem; - int result; - int sgn0, sgn1; - - /* If neither arg represents infinity, do the normal operation. - Else, if not a comparison, return infinity. Else handle the special - comparison rules. Note that most of the cases below won't occur, but - are handled for consistency. */ - - if (arg0 != 0 && arg1 != 0) - { - tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0), - arg0, convert (TREE_TYPE (arg0), arg1))); - STRIP_NOPS (tem); - return TREE_CODE (tem) == INTEGER_CST ? tem : 0; - } - - if (TREE_CODE_CLASS (code) != '<') - return 0; - - /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0 - for neither. Then compute our result treating them as never equal - and comparing bounds to non-bounds as above. */ - sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1); - sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1); - switch (code) - { - case EQ_EXPR: case NE_EXPR: - result = (code == NE_EXPR); - break; - case LT_EXPR: case LE_EXPR: - result = sgn0 < sgn1; - break; - case GT_EXPR: case GE_EXPR: - result = sgn0 > sgn1; - break; - } - - return convert (type, result ? integer_one_node : integer_zero_node); -} - -/* Given EXP, a logical expression, set the range it is testing into - variables denoted by PIN_P, PLOW, and PHIGH. Return the expression - actually being tested. *PLOW and *PHIGH will have be made the same type - as the returned expression. If EXP is not a comparison, we will most - likely not be returning a useful value and range. */ - -static tree -make_range (exp, pin_p, plow, phigh) - tree exp; - int *pin_p; - tree *plow, *phigh; -{ - enum tree_code code; - tree arg0, arg1, type; - int in_p, n_in_p; - tree low, high, n_low, n_high; - - /* Start with simply saying "EXP != 0" and then look at the code of EXP - and see if we can refine the range. Some of the cases below may not - happen, but it doesn't seem worth worrying about this. We "continue" - the outer loop when we've changed something; otherwise we "break" - the switch, which will "break" the while. */ - - in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node); - - while (1) - { - code = TREE_CODE (exp); - arg0 = TREE_OPERAND (exp, 0), arg1 = TREE_OPERAND (exp, 1); - if (TREE_CODE_CLASS (code) == '<' || TREE_CODE_CLASS (code) == '1' - || TREE_CODE_CLASS (code) == '2') - type = TREE_TYPE (arg0); - - switch (code) - { - case TRUTH_NOT_EXPR: - in_p = ! in_p, exp = arg0; - continue; - - case EQ_EXPR: case NE_EXPR: - case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR: - /* We can only do something if the range is testing for zero - and if the second operand is an integer constant. Note that - saying something is "in" the range we make is done by - complementing IN_P since it will set in the initial case of - being not equal to zero; "out" is leaving it alone. */ - if (low == 0 || high == 0 - || ! integer_zerop (low) || ! integer_zerop (high) - || TREE_CODE (arg1) != INTEGER_CST) - break; - - switch (code) - { - case NE_EXPR: /* - [c, c] */ - low = high = arg1; - break; - case EQ_EXPR: /* + [c, c] */ - in_p = ! in_p, low = high = arg1; - break; - case GT_EXPR: /* - [-, c] */ - low = 0, high = arg1; - break; - case GE_EXPR: /* + [c, -] */ - in_p = ! in_p, low = arg1, high = 0; - break; - case LT_EXPR: /* - [c, -] */ - low = arg1, high = 0; - break; - case LE_EXPR: /* + [-, c] */ - in_p = ! in_p, low = 0, high = arg1; - break; - } - - exp = arg0; - - /* If this is an unsigned comparison, we also know that EXP is - greater than or equal to zero. We base the range tests we make - on that fact, so we record it here so we can parse existing - range tests. */ - if (TREE_UNSIGNED (type) && (low == 0 || high == 0)) - { - if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high, - 1, convert (type, integer_zero_node), - NULL_TREE)) - break; - - in_p = n_in_p, low = n_low, high = n_high; - - /* If the high bound is missing, reverse the range so it - goes from zero to the low bound minus 1. */ - if (high == 0) - { - in_p = ! in_p; - high = range_binop (MINUS_EXPR, NULL_TREE, low, 0, - integer_one_node, 0); - low = convert (type, integer_zero_node); - } - } - continue; - - case NEGATE_EXPR: - /* (-x) IN [a,b] -> x in [-b, -a] */ - n_low = range_binop (MINUS_EXPR, type, - convert (type, integer_zero_node), 0, high, 1); - n_high = range_binop (MINUS_EXPR, type, - convert (type, integer_zero_node), 0, low, 0); - low = n_low, high = n_high; - exp = arg0; - continue; - - case BIT_NOT_EXPR: - /* ~ X -> -X - 1 */ - exp = build (MINUS_EXPR, type, build1 (NEGATE_EXPR, type, arg0), - convert (type, integer_one_node)); - continue; - - case PLUS_EXPR: case MINUS_EXPR: - if (TREE_CODE (arg1) != INTEGER_CST) - break; - - /* If EXP is signed, any overflow in the computation is undefined, - so we don't worry about it so long as our computations on - the bounds don't overflow. For unsigned, overflow is defined - and this is exactly the right thing. */ - n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR, - type, low, 0, arg1, 0); - n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR, - type, high, 1, arg1, 0); - if ((n_low != 0 && TREE_OVERFLOW (n_low)) - || (n_high != 0 && TREE_OVERFLOW (n_high))) - break; - - /* Check for an unsigned range which has wrapped around the maximum - value thus making n_high < n_low, and normalize it. */ - if (n_low && n_high && tree_int_cst_lt (n_high, n_low)) - { - low = range_binop (PLUS_EXPR, type, n_high, 0, - integer_one_node, 0); - high = range_binop (MINUS_EXPR, type, n_low, 0, - integer_one_node, 0); - in_p = ! in_p; - } - else - low = n_low, high = n_high; - - exp = arg0; - continue; - - case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR: - if (! INTEGRAL_TYPE_P (type) - || (low != 0 && ! int_fits_type_p (low, type)) - || (high != 0 && ! int_fits_type_p (high, type))) - break; - - if (low != 0) - low = convert (type, low); - - if (high != 0) - high = convert (type, high); - - exp = arg0; - continue; - } - - break; - } - - /* If EXP is a constant, we can evaluate whether this is true or false. */ - if (TREE_CODE (exp) == INTEGER_CST) - { - in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node, - exp, 0, low, 0)) - && integer_onep (range_binop (LE_EXPR, integer_type_node, - exp, 1, high, 1))); - low = high = 0; - exp = 0; - } - - *pin_p = in_p, *plow = low, *phigh = high; - return exp; -} - -/* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result - type, TYPE, return an expression to test if EXP is in (or out of, depending - on IN_P) the range. */ - -static tree -build_range_check (type, exp, in_p, low, high) - tree type; - tree exp; - int in_p; - tree low, high; -{ - tree etype = TREE_TYPE (exp); - tree utype, value; - - if (! in_p - && (0 != (value = build_range_check (type, exp, 1, low, high)))) - return invert_truthvalue (value); - - else if (low == 0 && high == 0) - return convert (type, integer_one_node); - - else if (low == 0) - return fold (build (LE_EXPR, type, exp, high)); - - else if (high == 0) - return fold (build (GE_EXPR, type, exp, low)); - - else if (operand_equal_p (low, high, 0)) - return fold (build (EQ_EXPR, type, exp, low)); - - else if (TREE_UNSIGNED (etype) && integer_zerop (low)) - return build_range_check (type, exp, 1, 0, high); - - else if (integer_zerop (low)) - { - utype = unsigned_type (etype); - return build_range_check (type, convert (utype, exp), 1, 0, - convert (utype, high)); - } - - else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0)) - && ! TREE_OVERFLOW (value)) - return build_range_check (type, - fold (build (MINUS_EXPR, etype, exp, low)), - 1, convert (etype, integer_zero_node), value); - else - return 0; -} - -/* Given two ranges, see if we can merge them into one. Return 1 if we - can, 0 if we can't. Set the output range into the specified parameters. */ - -static int -merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1) - int *pin_p; - tree *plow, *phigh; - int in0_p, in1_p; - tree low0, high0, low1, high1; -{ - int no_overlap; - int subset; - int temp; - tree tem; - int in_p; - tree low, high; - - /* Make range 0 be the range that starts first. Swap them if it isn't. */ - if (integer_onep (range_binop (GT_EXPR, integer_type_node, - low0, 0, low1, 0)) - || (((low0 == 0 && low1 == 0) - || integer_onep (range_binop (EQ_EXPR, integer_type_node, - low0, 0, low1, 0))) - && integer_onep (range_binop (GT_EXPR, integer_type_node, - high0, 1, high1, 1)))) - { - temp = in0_p, in0_p = in1_p, in1_p = temp; - tem = low0, low0 = low1, low1 = tem; - tem = high0, high0 = high1, high1 = tem; - } - - /* Now flag two cases, whether the ranges are disjoint or whether the - second range is totally subsumed in the first. Note that the tests - below are simplified by the ones above. */ - no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node, - high0, 1, low1, 0)); - subset = integer_onep (range_binop (LE_EXPR, integer_type_node, - high1, 1, high0, 1)); - - /* We now have four cases, depending on whether we are including or - excluding the two ranges. */ - if (in0_p && in1_p) - { - /* If they don't overlap, the result is false. If the second range - is a subset it is the result. Otherwise, the range is from the start - of the second to the end of the first. */ - if (no_overlap) - in_p = 0, low = high = 0; - else if (subset) - in_p = 1, low = low1, high = high1; - else - in_p = 1, low = low1, high = high0; - } - - else if (in0_p && ! in1_p) - { - /* If they don't overlap, the result is the first range. If the - second range is a subset of the first, we can't describe this as - a single range unless both ranges end at the same place. If both - ranges start in the same place, then the result is false. - Otherwise, we go from the start of the first range to just before - the start of the second. */ - if (no_overlap) - in_p = 1, low = low0, high = high0; - else if (subset - && integer_zerop (range_binop (EQ_EXPR, integer_type_node, - high0, 1, high1, 0))) - return 0; - else if (integer_onep (range_binop (EQ_EXPR, integer_type_node, - low0, 0, low1, 0))) - in_p = 0, low = high = 0; - else - { - in_p = 1, low = low0; - high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0, - integer_one_node, 0); - } - } - - else if (! in0_p && in1_p) - { - /* If they don't overlap, the result is the second range. If the second - is a subset of the first, the result is false. Otherwise, - the range starts just after the first range and ends at the - end of the second. */ - if (no_overlap) - in_p = 1, low = low1, high = high1; - else if (subset) - in_p = 0, low = high = 0; - else - { - in_p = 1, high = high1; - low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1, - integer_one_node, 0); - } - } - - else - { - /* The case where we are excluding both ranges. Here the complex case - is if they don't overlap. In that case, the only time we have a - range is if they are adjacent. If the second is a subset of the - first, the result is the first. Otherwise, the range to exclude - starts at the beginning of the first range and ends at the end of the - second. */ - if (no_overlap) - { - if (integer_onep (range_binop (EQ_EXPR, integer_type_node, - range_binop (PLUS_EXPR, NULL_TREE, - high0, 1, - integer_one_node, 1), - 1, low1, 0))) - in_p = 0, low = low0, high = high1; - else - return 0; - } - else if (subset) - in_p = 0, low = low0, high = high0; - else - in_p = 0, low = low0, high = high1; - } - - *pin_p = in_p, *plow = low, *phigh = high; - return 1; -} - -/* EXP is some logical combination of boolean tests. See if we can - merge it into some range test. Return the new tree if so. */ - -static tree -fold_range_test (exp) - tree exp; -{ - int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR - || TREE_CODE (exp) == TRUTH_OR_EXPR); - int in0_p, in1_p, in_p; - tree low0, low1, low, high0, high1, high; - tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0); - tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1); - tree tem; - - /* If this is an OR operation, invert both sides; we will invert - again at the end. */ - if (or_op) - in0_p = ! in0_p, in1_p = ! in1_p; - - /* If both expressions are the same, if we can merge the ranges, and we - can build the range test, return it or it inverted. If one of the - ranges is always true or always false, consider it to be the same - expression as the other. */ - if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0)) - && merge_ranges (&in_p, &low, &high, in0_p, low0, high0, - in1_p, low1, high1) - && 0 != (tem = (build_range_check (TREE_TYPE (exp), - lhs != 0 ? lhs - : rhs != 0 ? rhs : integer_zero_node, - in_p, low, high)))) - return or_op ? invert_truthvalue (tem) : tem; - - /* On machines where the branch cost is expensive, if this is a - short-circuited branch and the underlying object on both sides - is the same, make a non-short-circuit operation. */ - else if (BRANCH_COST >= 2 - && (TREE_CODE (exp) == TRUTH_ANDIF_EXPR - || TREE_CODE (exp) == TRUTH_ORIF_EXPR) - && operand_equal_p (lhs, rhs, 0)) - { - /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR. */ - if (simple_operand_p (lhs)) - return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR - ? TRUTH_AND_EXPR : TRUTH_OR_EXPR, - TREE_TYPE (exp), TREE_OPERAND (exp, 0), - TREE_OPERAND (exp, 1)); - else - { - tree common = save_expr (lhs); - - if (0 != (lhs = build_range_check (TREE_TYPE (exp), common, - or_op ? ! in0_p : in0_p, - low0, high0)) - && (0 != (rhs = build_range_check (TREE_TYPE (exp), common, - or_op ? ! in1_p : in1_p, - low1, high1)))) - return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR - ? TRUTH_AND_EXPR : TRUTH_OR_EXPR, - TREE_TYPE (exp), lhs, rhs); - } - } - else - return 0; -} - -/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P - bit value. Arrange things so the extra bits will be set to zero if and - only if C is signed-extended to its full width. If MASK is nonzero, - it is an INTEGER_CST that should be AND'ed with the extra bits. */ - -static tree -unextend (c, p, unsignedp, mask) - tree c; - int p; - int unsignedp; - tree mask; -{ - tree type = TREE_TYPE (c); - int modesize = GET_MODE_BITSIZE (TYPE_MODE (type)); - tree temp; - - if (p == modesize || unsignedp) - return c; - - /* We work by getting just the sign bit into the low-order bit, then - into the high-order bit, then sign-extend. We then XOR that value - with C. */ - temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0); - temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0); - - /* We must use a signed type in order to get an arithmetic right shift. - However, we must also avoid introducing accidental overflows, so that - a subsequent call to integer_zerop will work. Hence we must - do the type conversion here. At this point, the constant is either - zero or one, and the conversion to a signed type can never overflow. - We could get an overflow if this conversion is done anywhere else. */ - if (TREE_UNSIGNED (type)) - temp = convert (signed_type (type), temp); - - temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0); - temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0); - if (mask != 0) - temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0); - /* If necessary, convert the type back to match the type of C. */ - if (TREE_UNSIGNED (type)) - temp = convert (type, temp); - - return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0)); -} - -/* Find ways of folding logical expressions of LHS and RHS: - Try to merge two comparisons to the same innermost item. - Look for range tests like "ch >= '0' && ch <= '9'". - Look for combinations of simple terms on machines with expensive branches - and evaluate the RHS unconditionally. - - For example, if we have p->a == 2 && p->b == 4 and we can make an - object large enough to span both A and B, we can do this with a comparison - against the object ANDed with the a mask. - - If we have p->a == q->a && p->b == q->b, we may be able to use bit masking - operations to do this with one comparison. - - We check for both normal comparisons and the BIT_AND_EXPRs made this by - function and the one above. - - CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR, - TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR. - - TRUTH_TYPE is the type of the logical operand and LHS and RHS are its - two operands. - - We return the simplified tree or 0 if no optimization is possible. */ - -static tree -fold_truthop (code, truth_type, lhs, rhs) - enum tree_code code; - tree truth_type, lhs, rhs; -{ - /* If this is the "or" of two comparisons, we can do something if we - the comparisons are NE_EXPR. If this is the "and", we can do something - if the comparisons are EQ_EXPR. I.e., - (a->b == 2 && a->c == 4) can become (a->new == NEW). - - WANTED_CODE is this operation code. For single bit fields, we can - convert EQ_EXPR to NE_EXPR so we need not reject the "wrong" - comparison for one-bit fields. */ - - enum tree_code wanted_code; - enum tree_code lcode, rcode; - tree ll_arg, lr_arg, rl_arg, rr_arg; - tree ll_inner, lr_inner, rl_inner, rr_inner; - int ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos; - int rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos; - int xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos; - int lnbitsize, lnbitpos, rnbitsize, rnbitpos; - int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp; - enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode; - enum machine_mode lnmode, rnmode; - tree ll_mask, lr_mask, rl_mask, rr_mask; - tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask; - tree l_const, r_const; - tree type, result; - int first_bit, end_bit; - int volatilep; - - /* Start by getting the comparison codes. Fail if anything is volatile. - If one operand is a BIT_AND_EXPR with the constant one, treat it as if - it were surrounded with a NE_EXPR. */ - - if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs)) - return 0; - - lcode = TREE_CODE (lhs); - rcode = TREE_CODE (rhs); - - if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1))) - lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node); - - if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1))) - rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node); - - if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<') - return 0; - - code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR) - ? TRUTH_AND_EXPR : TRUTH_OR_EXPR); - - ll_arg = TREE_OPERAND (lhs, 0); - lr_arg = TREE_OPERAND (lhs, 1); - rl_arg = TREE_OPERAND (rhs, 0); - rr_arg = TREE_OPERAND (rhs, 1); - - /* If the RHS can be evaluated unconditionally and its operands are - simple, it wins to evaluate the RHS unconditionally on machines - with expensive branches. In this case, this isn't a comparison - that can be merged. */ - - /* @@ I'm not sure it wins on the m88110 to do this if the comparisons - are with zero (tmw). */ - - if (BRANCH_COST >= 2 - && INTEGRAL_TYPE_P (TREE_TYPE (rhs)) - && simple_operand_p (rl_arg) - && simple_operand_p (rr_arg)) - return build (code, truth_type, lhs, rhs); - - /* See if the comparisons can be merged. Then get all the parameters for - each side. */ - - if ((lcode != EQ_EXPR && lcode != NE_EXPR) - || (rcode != EQ_EXPR && rcode != NE_EXPR)) - return 0; - - volatilep = 0; - ll_inner = decode_field_reference (ll_arg, - &ll_bitsize, &ll_bitpos, &ll_mode, - &ll_unsignedp, &volatilep, &ll_mask, - &ll_and_mask); - lr_inner = decode_field_reference (lr_arg, - &lr_bitsize, &lr_bitpos, &lr_mode, - &lr_unsignedp, &volatilep, &lr_mask, - &lr_and_mask); - rl_inner = decode_field_reference (rl_arg, - &rl_bitsize, &rl_bitpos, &rl_mode, - &rl_unsignedp, &volatilep, &rl_mask, - &rl_and_mask); - rr_inner = decode_field_reference (rr_arg, - &rr_bitsize, &rr_bitpos, &rr_mode, - &rr_unsignedp, &volatilep, &rr_mask, - &rr_and_mask); - - /* It must be true that the inner operation on the lhs of each - comparison must be the same if we are to be able to do anything. - Then see if we have constants. If not, the same must be true for - the rhs's. */ - if (volatilep || ll_inner == 0 || rl_inner == 0 - || ! operand_equal_p (ll_inner, rl_inner, 0)) - return 0; - - if (TREE_CODE (lr_arg) == INTEGER_CST - && TREE_CODE (rr_arg) == INTEGER_CST) - l_const = lr_arg, r_const = rr_arg; - else if (lr_inner == 0 || rr_inner == 0 - || ! operand_equal_p (lr_inner, rr_inner, 0)) - return 0; - else - l_const = r_const = 0; - - /* If either comparison code is not correct for our logical operation, - fail. However, we can convert a one-bit comparison against zero into - the opposite comparison against that bit being set in the field. */ - - wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR); - if (lcode != wanted_code) - { - if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask)) - l_const = ll_mask; - else - return 0; - } - - if (rcode != wanted_code) - { - if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask)) - r_const = rl_mask; - else - return 0; - } - - /* See if we can find a mode that contains both fields being compared on - the left. If we can't, fail. Otherwise, update all constants and masks - to be relative to a field of that size. */ - first_bit = MIN (ll_bitpos, rl_bitpos); - end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); - lnmode = get_best_mode (end_bit - first_bit, first_bit, - TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, - volatilep); - if (lnmode == VOIDmode) - return 0; - - lnbitsize = GET_MODE_BITSIZE (lnmode); - lnbitpos = first_bit & ~ (lnbitsize - 1); - type = type_for_size (lnbitsize, 1); - xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos; - - if (BYTES_BIG_ENDIAN) - { - xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize; - xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize; - } - - ll_mask = const_binop (LSHIFT_EXPR, convert (type, ll_mask), - size_int (xll_bitpos), 0); - rl_mask = const_binop (LSHIFT_EXPR, convert (type, rl_mask), - size_int (xrl_bitpos), 0); - - if (l_const) - { - l_const = convert (type, l_const); - l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask); - l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0); - if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const, - fold (build1 (BIT_NOT_EXPR, - type, ll_mask)), - 0))) - { - warning ("comparison is always %s", - wanted_code == NE_EXPR ? "one" : "zero"); - - return convert (truth_type, - wanted_code == NE_EXPR - ? integer_one_node : integer_zero_node); - } - } - if (r_const) - { - r_const = convert (type, r_const); - r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask); - r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0); - if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const, - fold (build1 (BIT_NOT_EXPR, - type, rl_mask)), - 0))) - { - warning ("comparison is always %s", - wanted_code == NE_EXPR ? "one" : "zero"); - - return convert (truth_type, - wanted_code == NE_EXPR - ? integer_one_node : integer_zero_node); - } - } - - /* If the right sides are not constant, do the same for it. Also, - disallow this optimization if a size or signedness mismatch occurs - between the left and right sides. */ - if (l_const == 0) - { - if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize - || ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp - /* Make sure the two fields on the right - correspond to the left without being swapped. */ - || ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos) - return 0; - - first_bit = MIN (lr_bitpos, rr_bitpos); - end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); - rnmode = get_best_mode (end_bit - first_bit, first_bit, - TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, - volatilep); - if (rnmode == VOIDmode) - return 0; - - rnbitsize = GET_MODE_BITSIZE (rnmode); - rnbitpos = first_bit & ~ (rnbitsize - 1); - xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos; - - if (BYTES_BIG_ENDIAN) - { - xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize; - xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize; - } - - lr_mask = const_binop (LSHIFT_EXPR, convert (type, lr_mask), - size_int (xlr_bitpos), 0); - rr_mask = const_binop (LSHIFT_EXPR, convert (type, rr_mask), - size_int (xrr_bitpos), 0); - - /* Make a mask that corresponds to both fields being compared. - Do this for both items being compared. If the masks agree, - we can do this by masking both and comparing the masked - results. */ - ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); - lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0); - if (operand_equal_p (ll_mask, lr_mask, 0) && lnbitsize == rnbitsize) - { - lhs = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, - ll_unsignedp || rl_unsignedp); - rhs = make_bit_field_ref (lr_inner, type, rnbitsize, rnbitpos, - lr_unsignedp || rr_unsignedp); - if (! all_ones_mask_p (ll_mask, lnbitsize)) - { - lhs = build (BIT_AND_EXPR, type, lhs, ll_mask); - rhs = build (BIT_AND_EXPR, type, rhs, ll_mask); - } - return build (wanted_code, truth_type, lhs, rhs); - } - - /* There is still another way we can do something: If both pairs of - fields being compared are adjacent, we may be able to make a wider - field containing them both. */ - if ((ll_bitsize + ll_bitpos == rl_bitpos - && lr_bitsize + lr_bitpos == rr_bitpos) - || (ll_bitpos == rl_bitpos + rl_bitsize - && lr_bitpos == rr_bitpos + rr_bitsize)) - return build (wanted_code, truth_type, - make_bit_field_ref (ll_inner, type, - ll_bitsize + rl_bitsize, - MIN (ll_bitpos, rl_bitpos), - ll_unsignedp), - make_bit_field_ref (lr_inner, type, - lr_bitsize + rr_bitsize, - MIN (lr_bitpos, rr_bitpos), - lr_unsignedp)); - - return 0; - } - - /* Handle the case of comparisons with constants. If there is something in - common between the masks, those bits of the constants must be the same. - If not, the condition is always false. Test for this to avoid generating - incorrect code below. */ - result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0); - if (! integer_zerop (result) - && simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0), - const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1) - { - if (wanted_code == NE_EXPR) - { - warning ("`or' of unmatched not-equal tests is always 1"); - return convert (truth_type, integer_one_node); - } - else - { - warning ("`and' of mutually exclusive equal-tests is always zero"); - return convert (truth_type, integer_zero_node); - } - } - - /* Construct the expression we will return. First get the component - reference we will make. Unless the mask is all ones the width of - that field, perform the mask operation. Then compare with the - merged constant. */ - result = make_bit_field_ref (ll_inner, type, lnbitsize, lnbitpos, - ll_unsignedp || rl_unsignedp); - - ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0); - if (! all_ones_mask_p (ll_mask, lnbitsize)) - result = build (BIT_AND_EXPR, type, result, ll_mask); - - return build (wanted_code, truth_type, result, - const_binop (BIT_IOR_EXPR, l_const, r_const, 0)); -} - -/* If T contains a COMPOUND_EXPR which was inserted merely to evaluate - S, a SAVE_EXPR, return the expression actually being evaluated. Note - that we may sometimes modify the tree. */ - -static tree -strip_compound_expr (t, s) - tree t; - tree s; -{ - tree type = TREE_TYPE (t); - enum tree_code code = TREE_CODE (t); - - /* See if this is the COMPOUND_EXPR we want to eliminate. */ - if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR - && TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s) - return TREE_OPERAND (t, 1); - - /* See if this is a COND_EXPR or a simple arithmetic operator. We - don't bother handling any other types. */ - else if (code == COND_EXPR) - { - TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s); - TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s); - TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s); - } - else if (TREE_CODE_CLASS (code) == '1') - TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s); - else if (TREE_CODE_CLASS (code) == '<' - || TREE_CODE_CLASS (code) == '2') - { - TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s); - TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s); - } - - return t; -} - -/* Perform constant folding and related simplification of EXPR. - The related simplifications include x*1 => x, x*0 => 0, etc., - and application of the associative law. - NOP_EXPR conversions may be removed freely (as long as we - are careful not to change the C type of the overall expression) - We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR, - but we can constant-fold them if they have constant operands. */ - -tree -fold (expr) - tree expr; -{ - register tree t = expr; - tree t1 = NULL_TREE; - tree tem; - tree type = TREE_TYPE (expr); - register tree arg0, arg1; - register enum tree_code code = TREE_CODE (t); - register int kind; - int invert; - - /* WINS will be nonzero when the switch is done - if all operands are constant. */ - - int wins = 1; - - /* Don't try to process an RTL_EXPR since its operands aren't trees. - Likewise for a SAVE_EXPR that's already been evaluated. */ - if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t)) != 0) - return t; - - /* Return right away if already constant. */ - if (TREE_CONSTANT (t)) - { - if (code == CONST_DECL) - return DECL_INITIAL (t); - return t; - } - - kind = TREE_CODE_CLASS (code); - if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR) - { - tree subop; - - /* Special case for conversion ops that can have fixed point args. */ - arg0 = TREE_OPERAND (t, 0); - - /* Don't use STRIP_NOPS, because signedness of argument type matters. */ - if (arg0 != 0) - STRIP_TYPE_NOPS (arg0); - - if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST) - subop = TREE_REALPART (arg0); - else - subop = arg0; - - if (subop != 0 && TREE_CODE (subop) != INTEGER_CST -#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) - && TREE_CODE (subop) != REAL_CST -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - ) - /* Note that TREE_CONSTANT isn't enough: - static var addresses are constant but we can't - do arithmetic on them. */ - wins = 0; - } - else if (kind == 'e' || kind == '<' - || kind == '1' || kind == '2' || kind == 'r') - { - register int len = tree_code_length[(int) code]; - register int i; - for (i = 0; i < len; i++) - { - tree op = TREE_OPERAND (t, i); - tree subop; - - if (op == 0) - continue; /* Valid for CALL_EXPR, at least. */ - - if (kind == '<' || code == RSHIFT_EXPR) - { - /* Signedness matters here. Perhaps we can refine this - later. */ - STRIP_TYPE_NOPS (op); - } - else - { - /* Strip any conversions that don't change the mode. */ - STRIP_NOPS (op); - } - - if (TREE_CODE (op) == COMPLEX_CST) - subop = TREE_REALPART (op); - else - subop = op; - - if (TREE_CODE (subop) != INTEGER_CST -#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) - && TREE_CODE (subop) != REAL_CST -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - ) - /* Note that TREE_CONSTANT isn't enough: - static var addresses are constant but we can't - do arithmetic on them. */ - wins = 0; - - if (i == 0) - arg0 = op; - else if (i == 1) - arg1 = op; - } - } - - /* If this is a commutative operation, and ARG0 is a constant, move it - to ARG1 to reduce the number of tests below. */ - if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR - || code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR - || code == BIT_AND_EXPR) - && (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST)) - { - tem = arg0; arg0 = arg1; arg1 = tem; - - tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1); - TREE_OPERAND (t, 1) = tem; - } - - /* Now WINS is set as described above, - ARG0 is the first operand of EXPR, - and ARG1 is the second operand (if it has more than one operand). - - First check for cases where an arithmetic operation is applied to a - compound, conditional, or comparison operation. Push the arithmetic - operation inside the compound or conditional to see if any folding - can then be done. Convert comparison to conditional for this purpose. - The also optimizes non-constant cases that used to be done in - expand_expr. - - Before we do that, see if this is a BIT_AND_EXPR or a BIT_OR_EXPR, - one of the operands is a comparison and the other is a comparison, a - BIT_AND_EXPR with the constant 1, or a truth value. In that case, the - code below would make the expression more complex. Change it to a - TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to - TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */ - - if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR - || code == EQ_EXPR || code == NE_EXPR) - && ((truth_value_p (TREE_CODE (arg0)) - && (truth_value_p (TREE_CODE (arg1)) - || (TREE_CODE (arg1) == BIT_AND_EXPR - && integer_onep (TREE_OPERAND (arg1, 1))))) - || (truth_value_p (TREE_CODE (arg1)) - && (truth_value_p (TREE_CODE (arg0)) - || (TREE_CODE (arg0) == BIT_AND_EXPR - && integer_onep (TREE_OPERAND (arg0, 1))))))) - { - t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR - : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR - : TRUTH_XOR_EXPR, - type, arg0, arg1)); - - if (code == EQ_EXPR) - t = invert_truthvalue (t); - - return t; - } - - if (TREE_CODE_CLASS (code) == '1') - { - if (TREE_CODE (arg0) == COMPOUND_EXPR) - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), - fold (build1 (code, type, TREE_OPERAND (arg0, 1)))); - else if (TREE_CODE (arg0) == COND_EXPR) - { - t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0), - fold (build1 (code, type, TREE_OPERAND (arg0, 1))), - fold (build1 (code, type, TREE_OPERAND (arg0, 2))))); - - /* If this was a conversion, and all we did was to move into - inside the COND_EXPR, bring it back out. But leave it if - it is a conversion from integer to integer and the - result precision is no wider than a word since such a - conversion is cheap and may be optimized away by combine, - while it couldn't if it were outside the COND_EXPR. Then return - so we don't get into an infinite recursion loop taking the - conversion out and then back in. */ - - if ((code == NOP_EXPR || code == CONVERT_EXPR - || code == NON_LVALUE_EXPR) - && TREE_CODE (t) == COND_EXPR - && TREE_CODE (TREE_OPERAND (t, 1)) == code - && TREE_CODE (TREE_OPERAND (t, 2)) == code - && (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)) - == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0))) - && ! (INTEGRAL_TYPE_P (TREE_TYPE (t)) - && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))) - && TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD)) - t = build1 (code, type, - build (COND_EXPR, - TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0)), - TREE_OPERAND (t, 0), - TREE_OPERAND (TREE_OPERAND (t, 1), 0), - TREE_OPERAND (TREE_OPERAND (t, 2), 0))); - return t; - } - else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<') - return fold (build (COND_EXPR, type, arg0, - fold (build1 (code, type, integer_one_node)), - fold (build1 (code, type, integer_zero_node)))); - } - else if (TREE_CODE_CLASS (code) == '2' - || TREE_CODE_CLASS (code) == '<') - { - if (TREE_CODE (arg1) == COMPOUND_EXPR) - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), - fold (build (code, type, - arg0, TREE_OPERAND (arg1, 1)))); - else if (TREE_CODE (arg1) == COND_EXPR - || (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<' - && TREE_CODE_CLASS (code) != '<')) - { - tree test, true_value, false_value; - - if (TREE_CODE (arg1) == COND_EXPR) - { - test = TREE_OPERAND (arg1, 0); - true_value = TREE_OPERAND (arg1, 1); - false_value = TREE_OPERAND (arg1, 2); - } - else - { - tree testtype = TREE_TYPE (arg1); - test = arg1; - true_value = convert (testtype, integer_one_node); - false_value = convert (testtype, integer_zero_node); - } - - /* If ARG0 is complex we want to make sure we only evaluate - it once. Though this is only required if it is volatile, it - might be more efficient even if it is not. However, if we - succeed in folding one part to a constant, we do not need - to make this SAVE_EXPR. Since we do this optimization - primarily to see if we do end up with constant and this - SAVE_EXPR interferes with later optimizations, suppressing - it when we can is important. */ - - if (TREE_CODE (arg0) != SAVE_EXPR - && ((TREE_CODE (arg0) != VAR_DECL - && TREE_CODE (arg0) != PARM_DECL) - || TREE_SIDE_EFFECTS (arg0))) - { - tree lhs = fold (build (code, type, arg0, true_value)); - tree rhs = fold (build (code, type, arg0, false_value)); - - if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs)) - return fold (build (COND_EXPR, type, test, lhs, rhs)); - - arg0 = save_expr (arg0); - } - - test = fold (build (COND_EXPR, type, test, - fold (build (code, type, arg0, true_value)), - fold (build (code, type, arg0, false_value)))); - if (TREE_CODE (arg0) == SAVE_EXPR) - return build (COMPOUND_EXPR, type, - convert (void_type_node, arg0), - strip_compound_expr (test, arg0)); - else - return convert (type, test); - } - - else if (TREE_CODE (arg0) == COMPOUND_EXPR) - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), - fold (build (code, type, TREE_OPERAND (arg0, 1), arg1))); - else if (TREE_CODE (arg0) == COND_EXPR - || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<' - && TREE_CODE_CLASS (code) != '<')) - { - tree test, true_value, false_value; - - if (TREE_CODE (arg0) == COND_EXPR) - { - test = TREE_OPERAND (arg0, 0); - true_value = TREE_OPERAND (arg0, 1); - false_value = TREE_OPERAND (arg0, 2); - } - else - { - tree testtype = TREE_TYPE (arg0); - test = arg0; - true_value = convert (testtype, integer_one_node); - false_value = convert (testtype, integer_zero_node); - } - - if (TREE_CODE (arg1) != SAVE_EXPR - && ((TREE_CODE (arg1) != VAR_DECL - && TREE_CODE (arg1) != PARM_DECL) - || TREE_SIDE_EFFECTS (arg1))) - { - tree lhs = fold (build (code, type, true_value, arg1)); - tree rhs = fold (build (code, type, false_value, arg1)); - - if (TREE_CONSTANT (lhs) || TREE_CONSTANT (rhs) - || TREE_CONSTANT (arg1)) - return fold (build (COND_EXPR, type, test, lhs, rhs)); - - arg1 = save_expr (arg1); - } - - test = fold (build (COND_EXPR, type, test, - fold (build (code, type, true_value, arg1)), - fold (build (code, type, false_value, arg1)))); - if (TREE_CODE (arg1) == SAVE_EXPR) - return build (COMPOUND_EXPR, type, - convert (void_type_node, arg1), - strip_compound_expr (test, arg1)); - else - return convert (type, test); - } - } - else if (TREE_CODE_CLASS (code) == '<' - && TREE_CODE (arg0) == COMPOUND_EXPR) - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0), - fold (build (code, type, TREE_OPERAND (arg0, 1), arg1))); - else if (TREE_CODE_CLASS (code) == '<' - && TREE_CODE (arg1) == COMPOUND_EXPR) - return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0), - fold (build (code, type, arg0, TREE_OPERAND (arg1, 1)))); - - switch (code) - { - case INTEGER_CST: - case REAL_CST: - case STRING_CST: - case COMPLEX_CST: - case CONSTRUCTOR: - return t; - - case CONST_DECL: - return fold (DECL_INITIAL (t)); - - case NOP_EXPR: - case FLOAT_EXPR: - case CONVERT_EXPR: - case FIX_TRUNC_EXPR: - /* Other kinds of FIX are not handled properly by fold_convert. */ - - if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t)) - return TREE_OPERAND (t, 0); - - /* Handle cases of two conversions in a row. */ - if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR - || TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR) - { - tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)); - tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0)); - tree final_type = TREE_TYPE (t); - int inside_int = INTEGRAL_TYPE_P (inside_type); - int inside_ptr = POINTER_TYPE_P (inside_type); - int inside_float = FLOAT_TYPE_P (inside_type); - int inside_prec = TYPE_PRECISION (inside_type); - int inside_unsignedp = TREE_UNSIGNED (inside_type); - int inter_int = INTEGRAL_TYPE_P (inter_type); - int inter_ptr = POINTER_TYPE_P (inter_type); - int inter_float = FLOAT_TYPE_P (inter_type); - int inter_prec = TYPE_PRECISION (inter_type); - int inter_unsignedp = TREE_UNSIGNED (inter_type); - int final_int = INTEGRAL_TYPE_P (final_type); - int final_ptr = POINTER_TYPE_P (final_type); - int final_float = FLOAT_TYPE_P (final_type); - int final_prec = TYPE_PRECISION (final_type); - int final_unsignedp = TREE_UNSIGNED (final_type); - - /* In addition to the cases of two conversions in a row - handled below, if we are converting something to its own - type via an object of identical or wider precision, neither - conversion is needed. */ - if (inside_type == final_type - && ((inter_int && final_int) || (inter_float && final_float)) - && inter_prec >= final_prec) - return TREE_OPERAND (TREE_OPERAND (t, 0), 0); - - /* Likewise, if the intermediate and final types are either both - float or both integer, we don't need the middle conversion if - it is wider than the final type and doesn't change the signedness - (for integers). Avoid this if the final type is a pointer - since then we sometimes need the inner conversion. Likewise if - the outer has a precision not equal to the size of its mode. */ - if ((((inter_int || inter_ptr) && (inside_int || inside_ptr)) - || (inter_float && inside_float)) - && inter_prec >= inside_prec - && (inter_float || inter_unsignedp == inside_unsignedp) - && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type)) - && TYPE_MODE (final_type) == TYPE_MODE (inter_type)) - && ! final_ptr) - return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0)); - - /* Two conversions in a row are not needed unless: - - some conversion is floating-point (overstrict for now), or - - the intermediate type is narrower than both initial and - final, or - - the intermediate type and innermost type differ in signedness, - and the outermost type is wider than the intermediate, or - - the initial type is a pointer type and the precisions of the - intermediate and final types differ, or - - the final type is a pointer type and the precisions of the - initial and intermediate types differ. */ - if (! inside_float && ! inter_float && ! final_float - && (inter_prec > inside_prec || inter_prec > final_prec) - && ! (inside_int && inter_int - && inter_unsignedp != inside_unsignedp - && inter_prec < final_prec) - && ((inter_unsignedp && inter_prec > inside_prec) - == (final_unsignedp && final_prec > inter_prec)) - && ! (inside_ptr && inter_prec != final_prec) - && ! (final_ptr && inside_prec != inter_prec) - && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type)) - && TYPE_MODE (final_type) == TYPE_MODE (inter_type)) - && ! final_ptr) - return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0)); - } - - if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR - && TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1)) - /* Detect assigning a bitfield. */ - && !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF - && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1)))) - { - /* Don't leave an assignment inside a conversion - unless assigning a bitfield. */ - tree prev = TREE_OPERAND (t, 0); - TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1); - /* First do the assignment, then return converted constant. */ - t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t)); - TREE_USED (t) = 1; - return t; - } - if (!wins) - { - TREE_CONSTANT (t) = TREE_CONSTANT (arg0); - return t; - } - return fold_convert (t, arg0); - -#if 0 /* This loses on &"foo"[0]. */ - case ARRAY_REF: - { - int i; - - /* Fold an expression like: "foo"[2] */ - if (TREE_CODE (arg0) == STRING_CST - && TREE_CODE (arg1) == INTEGER_CST - && !TREE_INT_CST_HIGH (arg1) - && (i = TREE_INT_CST_LOW (arg1)) < TREE_STRING_LENGTH (arg0)) - { - t = build_int_2 (TREE_STRING_POINTER (arg0)[i], 0); - TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0)); - force_fit_type (t, 0); - } - } - return t; -#endif /* 0 */ - - case COMPONENT_REF: - if (TREE_CODE (arg0) == CONSTRUCTOR) - { - tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0)); - if (m) - t = TREE_VALUE (m); - } - return t; - - case RANGE_EXPR: - TREE_CONSTANT (t) = wins; - return t; - - case NEGATE_EXPR: - if (wins) - { - if (TREE_CODE (arg0) == INTEGER_CST) - { - HOST_WIDE_INT low, high; - int overflow = neg_double (TREE_INT_CST_LOW (arg0), - TREE_INT_CST_HIGH (arg0), - &low, &high); - t = build_int_2 (low, high); - TREE_TYPE (t) = type; - TREE_OVERFLOW (t) - = (TREE_OVERFLOW (arg0) - | force_fit_type (t, overflow && !TREE_UNSIGNED (type))); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0); - } - else if (TREE_CODE (arg0) == REAL_CST) - t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); - } - else if (TREE_CODE (arg0) == NEGATE_EXPR) - return TREE_OPERAND (arg0, 0); - - /* Convert - (a - b) to (b - a) for non-floating-point. */ - else if (TREE_CODE (arg0) == MINUS_EXPR && ! FLOAT_TYPE_P (type)) - return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg0, 0)); - - return t; - - case ABS_EXPR: - if (wins) - { - if (TREE_CODE (arg0) == INTEGER_CST) - { - if (! TREE_UNSIGNED (type) - && TREE_INT_CST_HIGH (arg0) < 0) - { - HOST_WIDE_INT low, high; - int overflow = neg_double (TREE_INT_CST_LOW (arg0), - TREE_INT_CST_HIGH (arg0), - &low, &high); - t = build_int_2 (low, high); - TREE_TYPE (t) = type; - TREE_OVERFLOW (t) - = (TREE_OVERFLOW (arg0) - | force_fit_type (t, overflow)); - TREE_CONSTANT_OVERFLOW (t) - = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0); - } - } - else if (TREE_CODE (arg0) == REAL_CST) - { - if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0))) - t = build_real (type, - REAL_VALUE_NEGATE (TREE_REAL_CST (arg0))); - } - } - else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR) - return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0)); - return t; - - case CONJ_EXPR: - if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) - return arg0; - else if (TREE_CODE (arg0) == COMPLEX_EXPR) - return build (COMPLEX_EXPR, TREE_TYPE (arg0), - TREE_OPERAND (arg0, 0), - fold (build1 (NEGATE_EXPR, - TREE_TYPE (TREE_TYPE (arg0)), - TREE_OPERAND (arg0, 1)))); - else if (TREE_CODE (arg0) == COMPLEX_CST) - return build_complex (type, TREE_OPERAND (arg0, 0), - fold (build1 (NEGATE_EXPR, - TREE_TYPE (TREE_TYPE (arg0)), - TREE_OPERAND (arg0, 1)))); - else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) - return fold (build (TREE_CODE (arg0), type, - fold (build1 (CONJ_EXPR, type, - TREE_OPERAND (arg0, 0))), - fold (build1 (CONJ_EXPR, - type, TREE_OPERAND (arg0, 1))))); - else if (TREE_CODE (arg0) == CONJ_EXPR) - return TREE_OPERAND (arg0, 0); - return t; - - case BIT_NOT_EXPR: - if (wins) - { - t = build_int_2 (~ TREE_INT_CST_LOW (arg0), - ~ TREE_INT_CST_HIGH (arg0)); - TREE_TYPE (t) = type; - force_fit_type (t, 0); - TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0); - TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0); - } - else if (TREE_CODE (arg0) == BIT_NOT_EXPR) - return TREE_OPERAND (arg0, 0); - return t; - - case PLUS_EXPR: - /* A + (-B) -> A - B */ - if (TREE_CODE (arg1) == NEGATE_EXPR) - return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); - else if (! FLOAT_TYPE_P (type)) - { - if (integer_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - - /* If we are adding two BIT_AND_EXPR's, both of which are and'ing - with a constant, and the two constants have no bits in common, - we should treat this as a BIT_IOR_EXPR since this may produce more - simplifications. */ - if (TREE_CODE (arg0) == BIT_AND_EXPR - && TREE_CODE (arg1) == BIT_AND_EXPR - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST - && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST - && integer_zerop (const_binop (BIT_AND_EXPR, - TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 1), 0))) - { - code = BIT_IOR_EXPR; - goto bit_ior; - } - - /* (A * C) + (B * C) -> (A+B) * C. Since we are most concerned - about the case where C is a constant, just try one of the - four possibilities. */ - - if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR - && operand_equal_p (TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 1), 0)) - return fold (build (MULT_EXPR, type, - fold (build (PLUS_EXPR, type, - TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0))), - TREE_OPERAND (arg0, 1))); - } - /* In IEEE floating point, x+0 may not equal x. */ - else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || flag_fast_math) - && real_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - associate: - /* In most languages, can't associate operations on floats - through parentheses. Rather than remember where the parentheses - were, we don't associate floats at all. It shouldn't matter much. - However, associating multiplications is only very slightly - inaccurate, so do that if -ffast-math is specified. */ - if (FLOAT_TYPE_P (type) - && ! (flag_fast_math && code == MULT_EXPR)) - goto binary; - - /* The varsign == -1 cases happen only for addition and subtraction. - It says that the arg that was split was really CON minus VAR. - The rest of the code applies to all associative operations. */ - if (!wins) - { - tree var, con; - int varsign; - - if (split_tree (arg0, code, &var, &con, &varsign)) - { - if (varsign == -1) - { - /* EXPR is (CON-VAR) +- ARG1. */ - /* If it is + and VAR==ARG1, return just CONST. */ - if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0)) - return convert (TREE_TYPE (t), con); - - /* If ARG0 is a constant, don't change things around; - instead keep all the constant computations together. */ - - if (TREE_CONSTANT (arg0)) - return t; - - /* Otherwise return (CON +- ARG1) - VAR. */ - t = build (MINUS_EXPR, type, - fold (build (code, type, con, arg1)), var); - } - else - { - /* EXPR is (VAR+CON) +- ARG1. */ - /* If it is - and VAR==ARG1, return just CONST. */ - if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0)) - return convert (TREE_TYPE (t), con); - - /* If ARG0 is a constant, don't change things around; - instead keep all the constant computations together. */ - - if (TREE_CONSTANT (arg0)) - return t; - - /* Otherwise return VAR +- (ARG1 +- CON). */ - tem = fold (build (code, type, arg1, con)); - t = build (code, type, var, tem); - - if (integer_zerop (tem) - && (code == PLUS_EXPR || code == MINUS_EXPR)) - return convert (type, var); - /* If we have x +/- (c - d) [c an explicit integer] - change it to x -/+ (d - c) since if d is relocatable - then the latter can be a single immediate insn - and the former cannot. */ - if (TREE_CODE (tem) == MINUS_EXPR - && TREE_CODE (TREE_OPERAND (tem, 0)) == INTEGER_CST) - { - tree tem1 = TREE_OPERAND (tem, 1); - TREE_OPERAND (tem, 1) = TREE_OPERAND (tem, 0); - TREE_OPERAND (tem, 0) = tem1; - TREE_SET_CODE (t, - (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); - } - } - return t; - } - - if (split_tree (arg1, code, &var, &con, &varsign)) - { - if (TREE_CONSTANT (arg1)) - return t; - - if (varsign == -1) - TREE_SET_CODE (t, - (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR)); - - /* EXPR is ARG0 +- (CON +- VAR). */ - if (TREE_CODE (t) == MINUS_EXPR - && operand_equal_p (var, arg0, 0)) - { - /* If VAR and ARG0 cancel, return just CON or -CON. */ - if (code == PLUS_EXPR) - return convert (TREE_TYPE (t), con); - return fold (build1 (NEGATE_EXPR, TREE_TYPE (t), - convert (TREE_TYPE (t), con))); - } - - t = build (TREE_CODE (t), type, - fold (build (code, TREE_TYPE (t), arg0, con)), var); - - if (integer_zerop (TREE_OPERAND (t, 0)) - && TREE_CODE (t) == PLUS_EXPR) - return convert (TREE_TYPE (t), var); - return t; - } - } - binary: -#if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC) - if (TREE_CODE (arg1) == REAL_CST) - return t; -#endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */ - if (wins) - t1 = const_binop (code, arg0, arg1, 0); - if (t1 != NULL_TREE) - { - /* The return value should always have - the same type as the original expression. */ - if (TREE_TYPE (t1) != TREE_TYPE (t)) - t1 = convert (TREE_TYPE (t), t1); - - return t1; - } - return t; - - case MINUS_EXPR: - if (! FLOAT_TYPE_P (type)) - { - if (! wins && integer_zerop (arg0)) - return build1 (NEGATE_EXPR, type, arg1); - if (integer_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - - /* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned - about the case where C is a constant, just try one of the - four possibilities. */ - - if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR - && operand_equal_p (TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg1, 1), 0)) - return fold (build (MULT_EXPR, type, - fold (build (MINUS_EXPR, type, - TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg1, 0))), - TREE_OPERAND (arg0, 1))); - } - /* Convert A - (-B) to A + B. */ - else if (TREE_CODE (arg1) == NEGATE_EXPR) - return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0))); - - else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || flag_fast_math) - { - /* Except with IEEE floating point, 0-x equals -x. */ - if (! wins && real_zerop (arg0)) - return build1 (NEGATE_EXPR, type, arg1); - /* Except with IEEE floating point, x-0 equals x. */ - if (real_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - } - - /* Fold &x - &x. This can happen from &x.foo - &x. - This is unsafe for certain floats even in non-IEEE formats. - In IEEE, it is unsafe because it does wrong for NaNs. - Also note that operand_equal_p is always false if an operand - is volatile. */ - - if ((! FLOAT_TYPE_P (type) || flag_fast_math) - && operand_equal_p (arg0, arg1, 0)) - return convert (type, integer_zero_node); - - goto associate; - - case MULT_EXPR: - if (! FLOAT_TYPE_P (type)) - { - if (integer_zerop (arg1)) - return omit_one_operand (type, arg1, arg0); - if (integer_onep (arg1)) - return non_lvalue (convert (type, arg0)); - - /* ((A / C) * C) is A if the division is an - EXACT_DIV_EXPR. Since C is normally a constant, - just check for one of the four possibilities. */ - - if (TREE_CODE (arg0) == EXACT_DIV_EXPR - && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) - return TREE_OPERAND (arg0, 0); - - /* (a * (1 << b)) is (a << b) */ - if (TREE_CODE (arg1) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (arg1, 0))) - return fold (build (LSHIFT_EXPR, type, arg0, - TREE_OPERAND (arg1, 1))); - if (TREE_CODE (arg0) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (arg0, 0))) - return fold (build (LSHIFT_EXPR, type, arg1, - TREE_OPERAND (arg0, 1))); - } - else - { - /* x*0 is 0, except for IEEE floating point. */ - if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || flag_fast_math) - && real_zerop (arg1)) - return omit_one_operand (type, arg1, arg0); - /* In IEEE floating point, x*1 is not equivalent to x for snans. - However, ANSI says we can drop signals, - so we can do this anyway. */ - if (real_onep (arg1)) - return non_lvalue (convert (type, arg0)); - /* x*2 is x+x */ - if (! wins && real_twop (arg1)) - { - tree arg = save_expr (arg0); - return build (PLUS_EXPR, type, arg, arg); - } - } - goto associate; - - case BIT_IOR_EXPR: - bit_ior: - { - register enum tree_code code0, code1; - - if (integer_all_onesp (arg1)) - return omit_one_operand (type, arg1, arg0); - if (integer_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - t1 = distribute_bit_expr (code, type, arg0, arg1); - if (t1 != NULL_TREE) - return t1; - - /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A - is a rotate of A by C1 bits. */ - /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A - is a rotate of A by B bits. */ - - code0 = TREE_CODE (arg0); - code1 = TREE_CODE (arg1); - if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR) - || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR)) - && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0) - && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) - { - register tree tree01, tree11; - register enum tree_code code01, code11; - - tree01 = TREE_OPERAND (arg0, 1); - tree11 = TREE_OPERAND (arg1, 1); - code01 = TREE_CODE (tree01); - code11 = TREE_CODE (tree11); - if (code01 == INTEGER_CST - && code11 == INTEGER_CST - && TREE_INT_CST_HIGH (tree01) == 0 - && TREE_INT_CST_HIGH (tree11) == 0 - && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11)) - == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))) - return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0), - code0 == LSHIFT_EXPR ? tree01 : tree11); - else if (code11 == MINUS_EXPR - && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST - && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0 - && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0)) - == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))) - && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0)) - return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR, - type, TREE_OPERAND (arg0, 0), tree01); - else if (code01 == MINUS_EXPR - && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST - && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0 - && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0)) - == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))) - && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0)) - return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR, - type, TREE_OPERAND (arg0, 0), tree11); - } - - goto associate; - } - - case BIT_XOR_EXPR: - if (integer_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - if (integer_all_onesp (arg1)) - return fold (build1 (BIT_NOT_EXPR, type, arg0)); - goto associate; - - case BIT_AND_EXPR: - bit_and: - if (integer_all_onesp (arg1)) - return non_lvalue (convert (type, arg0)); - if (integer_zerop (arg1)) - return omit_one_operand (type, arg1, arg0); - t1 = distribute_bit_expr (code, type, arg0, arg1); - if (t1 != NULL_TREE) - return t1; - /* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */ - if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR - && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0)))) - { - int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0))); - if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT - && (~TREE_INT_CST_LOW (arg0) - & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) - return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0)); - } - if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR - && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) - { - int prec = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))); - if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT - && (~TREE_INT_CST_LOW (arg1) - & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) - return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0)); - } - goto associate; - - case BIT_ANDTC_EXPR: - if (integer_all_onesp (arg0)) - return non_lvalue (convert (type, arg1)); - if (integer_zerop (arg0)) - return omit_one_operand (type, arg0, arg1); - if (TREE_CODE (arg1) == INTEGER_CST) - { - arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1)); - code = BIT_AND_EXPR; - goto bit_and; - } - goto binary; - - case RDIV_EXPR: - /* In most cases, do nothing with a divide by zero. */ -#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC) -#ifndef REAL_INFINITY - if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1)) - return t; -#endif -#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */ - - /* In IEEE floating point, x/1 is not equivalent to x for snans. - However, ANSI says we can drop signals, so we can do this anyway. */ - if (real_onep (arg1)) - return non_lvalue (convert (type, arg0)); - - /* If ARG1 is a constant, we can convert this to a multiply by the - reciprocal. This does not have the same rounding properties, - so only do this if -ffast-math. We can actually always safely - do it if ARG1 is a power of two, but it's hard to tell if it is - or not in a portable manner. */ - if (TREE_CODE (arg1) == REAL_CST) - { - if (flag_fast_math - && 0 != (tem = const_binop (code, build_real (type, dconst1), - arg1, 0))) - return fold (build (MULT_EXPR, type, arg0, tem)); - /* Find the reciprocal if optimizing and the result is exact. */ - else if (optimize) - { - REAL_VALUE_TYPE r; - r = TREE_REAL_CST (arg1); - if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r)) - { - tem = build_real (type, r); - return fold (build (MULT_EXPR, type, arg0, tem)); - } - } - } - goto binary; - - case TRUNC_DIV_EXPR: - case ROUND_DIV_EXPR: - case FLOOR_DIV_EXPR: - case CEIL_DIV_EXPR: - case EXACT_DIV_EXPR: - if (integer_onep (arg1)) - return non_lvalue (convert (type, arg0)); - if (integer_zerop (arg1)) - return t; - - /* If we have ((a / C1) / C2) where both division are the same type, try - to simplify. First see if C1 * C2 overflows or not. */ - if (TREE_CODE (arg0) == code && TREE_CODE (arg1) == INTEGER_CST - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) - { - tree new_divisor; - - new_divisor = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 1), arg1, 0); - tem = const_binop (FLOOR_DIV_EXPR, new_divisor, arg1, 0); - - if (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_LOW (tem) - && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == TREE_INT_CST_HIGH (tem)) - { - /* If no overflow, divide by C1*C2. */ - return fold (build (code, type, TREE_OPERAND (arg0, 0), new_divisor)); - } - } - - /* Look for ((a * C1) / C3) or (((a * C1) + C2) / C3), - where C1 % C3 == 0 or C3 % C1 == 0. We can simplify these - expressions, which often appear in the offsets or sizes of - objects with a varying size. Only deal with positive divisors - and multiplicands. If C2 is negative, we must have C2 % C3 == 0. - - Look for NOPs and SAVE_EXPRs inside. */ - - if (TREE_CODE (arg1) == INTEGER_CST - && tree_int_cst_sgn (arg1) >= 0) - { - int have_save_expr = 0; - tree c2 = integer_zero_node; - tree xarg0 = arg0; - - if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0) - have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0); - - STRIP_NOPS (xarg0); - - if (TREE_CODE (xarg0) == PLUS_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST) - c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0); - else if (TREE_CODE (xarg0) == MINUS_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST - /* If we are doing this computation unsigned, the negate - is incorrect. */ - && ! TREE_UNSIGNED (type)) - { - c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1))); - xarg0 = TREE_OPERAND (xarg0, 0); - } - - if (TREE_CODE (xarg0) == SAVE_EXPR && SAVE_EXPR_RTL (xarg0) == 0) - have_save_expr = 1, xarg0 = TREE_OPERAND (xarg0, 0); - - STRIP_NOPS (xarg0); - - if (TREE_CODE (xarg0) == MULT_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST - && tree_int_cst_sgn (TREE_OPERAND (xarg0, 1)) >= 0 - && (integer_zerop (const_binop (TRUNC_MOD_EXPR, - TREE_OPERAND (xarg0, 1), arg1, 1)) - || integer_zerop (const_binop (TRUNC_MOD_EXPR, arg1, - TREE_OPERAND (xarg0, 1), 1))) - && (tree_int_cst_sgn (c2) >= 0 - || integer_zerop (const_binop (TRUNC_MOD_EXPR, c2, - arg1, 1)))) - { - tree outer_div = integer_one_node; - tree c1 = TREE_OPERAND (xarg0, 1); - tree c3 = arg1; - - /* If C3 > C1, set them equal and do a divide by - C3/C1 at the end of the operation. */ - if (tree_int_cst_lt (c1, c3)) - outer_div = const_binop (code, c3, c1, 0), c3 = c1; - - /* The result is A * (C1/C3) + (C2/C3). */ - t = fold (build (PLUS_EXPR, type, - fold (build (MULT_EXPR, type, - TREE_OPERAND (xarg0, 0), - const_binop (code, c1, c3, 1))), - const_binop (code, c2, c3, 1))); - - if (! integer_onep (outer_div)) - t = fold (build (code, type, t, convert (type, outer_div))); - - if (have_save_expr) - t = save_expr (t); - - return t; - } - } - - goto binary; - - case CEIL_MOD_EXPR: - case FLOOR_MOD_EXPR: - case ROUND_MOD_EXPR: - case TRUNC_MOD_EXPR: - if (integer_onep (arg1)) - return omit_one_operand (type, integer_zero_node, arg0); - if (integer_zerop (arg1)) - return t; - - /* Look for ((a * C1) % C3) or (((a * C1) + C2) % C3), - where C1 % C3 == 0. Handle similarly to the division case, - but don't bother with SAVE_EXPRs. */ - - if (TREE_CODE (arg1) == INTEGER_CST - && ! integer_zerop (arg1)) - { - tree c2 = integer_zero_node; - tree xarg0 = arg0; - - if (TREE_CODE (xarg0) == PLUS_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST) - c2 = TREE_OPERAND (xarg0, 1), xarg0 = TREE_OPERAND (xarg0, 0); - else if (TREE_CODE (xarg0) == MINUS_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST - && ! TREE_UNSIGNED (type)) - { - c2 = fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (xarg0, 1))); - xarg0 = TREE_OPERAND (xarg0, 0); - } - - STRIP_NOPS (xarg0); - - if (TREE_CODE (xarg0) == MULT_EXPR - && TREE_CODE (TREE_OPERAND (xarg0, 1)) == INTEGER_CST - && integer_zerop (const_binop (TRUNC_MOD_EXPR, - TREE_OPERAND (xarg0, 1), - arg1, 1)) - && tree_int_cst_sgn (c2) >= 0) - /* The result is (C2%C3). */ - return omit_one_operand (type, const_binop (code, c2, arg1, 1), - TREE_OPERAND (xarg0, 0)); - } - - goto binary; - - case LSHIFT_EXPR: - case RSHIFT_EXPR: - case LROTATE_EXPR: - case RROTATE_EXPR: - if (integer_zerop (arg1)) - return non_lvalue (convert (type, arg0)); - /* Since negative shift count is not well-defined, - don't try to compute it in the compiler. */ - if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0) - return t; - /* Rewrite an LROTATE_EXPR by a constant into an - RROTATE_EXPR by a new constant. */ - if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST) - { - TREE_SET_CODE (t, RROTATE_EXPR); - code = RROTATE_EXPR; - TREE_OPERAND (t, 1) = arg1 - = const_binop - (MINUS_EXPR, - convert (TREE_TYPE (arg1), - build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)), - arg1, 0); - if (tree_int_cst_sgn (arg1) < 0) - return t; - } - - /* If we have a rotate of a bit operation with the rotate count and - the second operand of the bit operation both constant, - permute the two operations. */ - if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST - && (TREE_CODE (arg0) == BIT_AND_EXPR - || TREE_CODE (arg0) == BIT_ANDTC_EXPR - || TREE_CODE (arg0) == BIT_IOR_EXPR - || TREE_CODE (arg0) == BIT_XOR_EXPR) - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) - return fold (build (TREE_CODE (arg0), type, - fold (build (code, type, - TREE_OPERAND (arg0, 0), arg1)), - fold (build (code, type, - TREE_OPERAND (arg0, 1), arg1)))); - - /* Two consecutive rotates adding up to the width of the mode can - be ignored. */ - if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST - && TREE_CODE (arg0) == RROTATE_EXPR - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST - && TREE_INT_CST_HIGH (arg1) == 0 - && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0 - && ((TREE_INT_CST_LOW (arg1) - + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1))) - == GET_MODE_BITSIZE (TYPE_MODE (type)))) - return TREE_OPERAND (arg0, 0); - - goto binary; - - case MIN_EXPR: - if (operand_equal_p (arg0, arg1, 0)) - return arg0; - if (INTEGRAL_TYPE_P (type) - && operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1)) - return omit_one_operand (type, arg1, arg0); - goto associate; - - case MAX_EXPR: - if (operand_equal_p (arg0, arg1, 0)) - return arg0; - if (INTEGRAL_TYPE_P (type) - && operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1)) - return omit_one_operand (type, arg1, arg0); - goto associate; - - case TRUTH_NOT_EXPR: - /* Note that the operand of this must be an int - and its values must be 0 or 1. - ("true" is a fixed value perhaps depending on the language, - but we don't handle values other than 1 correctly yet.) */ - tem = invert_truthvalue (arg0); - /* Avoid infinite recursion. */ - if (TREE_CODE (tem) == TRUTH_NOT_EXPR) - return t; - return convert (type, tem); - - case TRUTH_ANDIF_EXPR: - /* Note that the operands of this must be ints - and their values must be 0 or 1. - ("true" is a fixed value perhaps depending on the language.) */ - /* If first arg is constant zero, return it. */ - if (integer_zerop (arg0)) - return arg0; - case TRUTH_AND_EXPR: - /* If either arg is constant true, drop it. */ - if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) - return non_lvalue (arg1); - if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) - return non_lvalue (arg0); - /* If second arg is constant zero, result is zero, but first arg - must be evaluated. */ - if (integer_zerop (arg1)) - return omit_one_operand (type, arg1, arg0); - /* Likewise for first arg, but note that only the TRUTH_AND_EXPR - case will be handled here. */ - if (integer_zerop (arg0)) - return omit_one_operand (type, arg0, arg1); - - truth_andor: - /* We only do these simplifications if we are optimizing. */ - if (!optimize) - return t; - - /* Check for things like (A || B) && (A || C). We can convert this - to A || (B && C). Note that either operator can be any of the four - truth and/or operations and the transformation will still be - valid. Also note that we only care about order for the - ANDIF and ORIF operators. */ - if (TREE_CODE (arg0) == TREE_CODE (arg1) - && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR - || TREE_CODE (arg0) == TRUTH_ORIF_EXPR - || TREE_CODE (arg0) == TRUTH_AND_EXPR - || TREE_CODE (arg0) == TRUTH_OR_EXPR)) - { - tree a00 = TREE_OPERAND (arg0, 0); - tree a01 = TREE_OPERAND (arg0, 1); - tree a10 = TREE_OPERAND (arg1, 0); - tree a11 = TREE_OPERAND (arg1, 1); - int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR - || TREE_CODE (arg0) == TRUTH_AND_EXPR) - && (code == TRUTH_AND_EXPR - || code == TRUTH_OR_EXPR)); - - if (operand_equal_p (a00, a10, 0)) - return fold (build (TREE_CODE (arg0), type, a00, - fold (build (code, type, a01, a11)))); - else if (commutative && operand_equal_p (a00, a11, 0)) - return fold (build (TREE_CODE (arg0), type, a00, - fold (build (code, type, a01, a10)))); - else if (commutative && operand_equal_p (a01, a10, 0)) - return fold (build (TREE_CODE (arg0), type, a01, - fold (build (code, type, a00, a11)))); - - /* This case if tricky because we must either have commutative - operators or else A10 must not have side-effects. */ - - else if ((commutative || ! TREE_SIDE_EFFECTS (a10)) - && operand_equal_p (a01, a11, 0)) - return fold (build (TREE_CODE (arg0), type, - fold (build (code, type, a00, a10)), - a01)); - } - - /* See if we can build a range comparison. */ - if (0 != (tem = fold_range_test (t))) - return tem; - - /* Check for the possibility of merging component references. If our - lhs is another similar operation, try to merge its rhs with our - rhs. Then try to merge our lhs and rhs. */ - if (TREE_CODE (arg0) == code - && 0 != (tem = fold_truthop (code, type, - TREE_OPERAND (arg0, 1), arg1))) - return fold (build (code, type, TREE_OPERAND (arg0, 0), tem)); - - if ((tem = fold_truthop (code, type, arg0, arg1)) != 0) - return tem; - - return t; - - case TRUTH_ORIF_EXPR: - /* Note that the operands of this must be ints - and their values must be 0 or true. - ("true" is a fixed value perhaps depending on the language.) */ - /* If first arg is constant true, return it. */ - if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) - return arg0; - case TRUTH_OR_EXPR: - /* If either arg is constant zero, drop it. */ - if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0)) - return non_lvalue (arg1); - if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)) - return non_lvalue (arg0); - /* If second arg is constant true, result is true, but we must - evaluate first arg. */ - if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)) - return omit_one_operand (type, arg1, arg0); - /* Likewise for first arg, but note this only occurs here for - TRUTH_OR_EXPR. */ - if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) - return omit_one_operand (type, arg0, arg1); - goto truth_andor; - - case TRUTH_XOR_EXPR: - /* If either arg is constant zero, drop it. */ - if (integer_zerop (arg0)) - return non_lvalue (arg1); - if (integer_zerop (arg1)) - return non_lvalue (arg0); - /* If either arg is constant true, this is a logical inversion. */ - if (integer_onep (arg0)) - return non_lvalue (invert_truthvalue (arg1)); - if (integer_onep (arg1)) - return non_lvalue (invert_truthvalue (arg0)); - return t; - - case EQ_EXPR: - case NE_EXPR: - case LT_EXPR: - case GT_EXPR: - case LE_EXPR: - case GE_EXPR: - /* If one arg is a constant integer, put it last. */ - if (TREE_CODE (arg0) == INTEGER_CST - && TREE_CODE (arg1) != INTEGER_CST) - { - TREE_OPERAND (t, 0) = arg1; - TREE_OPERAND (t, 1) = arg0; - arg0 = TREE_OPERAND (t, 0); - arg1 = TREE_OPERAND (t, 1); - code = swap_tree_comparison (code); - TREE_SET_CODE (t, code); - } - - /* Convert foo++ == CONST into ++foo == CONST + INCR. - First, see if one arg is constant; find the constant arg - and the other one. */ - { - tree constop = 0, varop; - int constopnum = -1; - - if (TREE_CONSTANT (arg1)) - constopnum = 1, constop = arg1, varop = arg0; - if (TREE_CONSTANT (arg0)) - constopnum = 0, constop = arg0, varop = arg1; - - if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR) - { - /* This optimization is invalid for ordered comparisons - if CONST+INCR overflows or if foo+incr might overflow. - This optimization is invalid for floating point due to rounding. - For pointer types we assume overflow doesn't happen. */ - if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE - || (! FLOAT_TYPE_P (TREE_TYPE (varop)) - && (code == EQ_EXPR || code == NE_EXPR))) - { - tree newconst - = fold (build (PLUS_EXPR, TREE_TYPE (varop), - constop, TREE_OPERAND (varop, 1))); - TREE_SET_CODE (varop, PREINCREMENT_EXPR); - - /* If VAROP is a reference to a bitfield, we must mask - the constant by the width of the field. */ - if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF - && DECL_BIT_FIELD(TREE_OPERAND - (TREE_OPERAND (varop, 0), 1))) - { - int size - = TREE_INT_CST_LOW (DECL_SIZE - (TREE_OPERAND - (TREE_OPERAND (varop, 0), 1))); - - newconst = fold (build (BIT_AND_EXPR, - TREE_TYPE (varop), newconst, - convert (TREE_TYPE (varop), - build_int_2 (size, 0)))); - } - - - t = build (code, type, TREE_OPERAND (t, 0), - TREE_OPERAND (t, 1)); - TREE_OPERAND (t, constopnum) = newconst; - return t; - } - } - else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR) - { - if (TREE_CODE (TREE_TYPE (varop)) == POINTER_TYPE - || (! FLOAT_TYPE_P (TREE_TYPE (varop)) - && (code == EQ_EXPR || code == NE_EXPR))) - { - tree newconst - = fold (build (MINUS_EXPR, TREE_TYPE (varop), - constop, TREE_OPERAND (varop, 1))); - TREE_SET_CODE (varop, PREDECREMENT_EXPR); - - if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF - && DECL_BIT_FIELD(TREE_OPERAND - (TREE_OPERAND (varop, 0), 1))) - { - int size - = TREE_INT_CST_LOW (DECL_SIZE - (TREE_OPERAND - (TREE_OPERAND (varop, 0), 1))); - - newconst = fold (build (BIT_AND_EXPR, - TREE_TYPE (varop), newconst, - convert (TREE_TYPE (varop), - build_int_2 (size, 0)))); - } - - - t = build (code, type, TREE_OPERAND (t, 0), - TREE_OPERAND (t, 1)); - TREE_OPERAND (t, constopnum) = newconst; - return t; - } - } - } - - /* Change X >= CST to X > (CST - 1) if CST is positive. */ - if (TREE_CODE (arg1) == INTEGER_CST - && TREE_CODE (arg0) != INTEGER_CST - && tree_int_cst_sgn (arg1) > 0) - { - switch (TREE_CODE (t)) - { - case GE_EXPR: - code = GT_EXPR; - arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); - t = build (code, type, TREE_OPERAND (t, 0), arg1); - break; - - case LT_EXPR: - code = LE_EXPR; - arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0); - t = build (code, type, TREE_OPERAND (t, 0), arg1); - break; - } - } - - /* If this is an EQ or NE comparison with zero and ARG0 is - (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require - two operations, but the latter can be done in one less insn - one machine that have only two-operand insns or on which a - constant cannot be the first operand. */ - if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR) - && TREE_CODE (arg0) == BIT_AND_EXPR) - { - if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0))) - return - fold (build (code, type, - build (BIT_AND_EXPR, TREE_TYPE (arg0), - build (RSHIFT_EXPR, - TREE_TYPE (TREE_OPERAND (arg0, 0)), - TREE_OPERAND (arg0, 1), - TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)), - convert (TREE_TYPE (arg0), - integer_one_node)), - arg1)); - else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0))) - return - fold (build (code, type, - build (BIT_AND_EXPR, TREE_TYPE (arg0), - build (RSHIFT_EXPR, - TREE_TYPE (TREE_OPERAND (arg0, 1)), - TREE_OPERAND (arg0, 0), - TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)), - convert (TREE_TYPE (arg0), - integer_one_node)), - arg1)); - } - - /* If this is an NE or EQ comparison of zero against the result of a - signed MOD operation whose second operand is a power of 2, make - the MOD operation unsigned since it is simpler and equivalent. */ - if ((code == NE_EXPR || code == EQ_EXPR) - && integer_zerop (arg1) - && ! TREE_UNSIGNED (TREE_TYPE (arg0)) - && (TREE_CODE (arg0) == TRUNC_MOD_EXPR - || TREE_CODE (arg0) == CEIL_MOD_EXPR - || TREE_CODE (arg0) == FLOOR_MOD_EXPR - || TREE_CODE (arg0) == ROUND_MOD_EXPR) - && integer_pow2p (TREE_OPERAND (arg0, 1))) - { - tree newtype = unsigned_type (TREE_TYPE (arg0)); - tree newmod = build (TREE_CODE (arg0), newtype, - convert (newtype, TREE_OPERAND (arg0, 0)), - convert (newtype, TREE_OPERAND (arg0, 1))); - - return build (code, type, newmod, convert (newtype, arg1)); - } - - /* If this is an NE comparison of zero with an AND of one, remove the - comparison since the AND will give the correct value. */ - if (code == NE_EXPR && integer_zerop (arg1) - && TREE_CODE (arg0) == BIT_AND_EXPR - && integer_onep (TREE_OPERAND (arg0, 1))) - return convert (type, arg0); - - /* If we have (A & C) == C where C is a power of 2, convert this into - (A & C) != 0. Similarly for NE_EXPR. */ - if ((code == EQ_EXPR || code == NE_EXPR) - && TREE_CODE (arg0) == BIT_AND_EXPR - && integer_pow2p (TREE_OPERAND (arg0, 1)) - && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0)) - return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type, - arg0, integer_zero_node); - - /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0 - and similarly for >= into !=. */ - if ((code == LT_EXPR || code == GE_EXPR) - && TREE_UNSIGNED (TREE_TYPE (arg0)) - && TREE_CODE (arg1) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (arg1, 0))) - return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type, - build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0, - TREE_OPERAND (arg1, 1)), - convert (TREE_TYPE (arg0), integer_zero_node)); - - else if ((code == LT_EXPR || code == GE_EXPR) - && TREE_UNSIGNED (TREE_TYPE (arg0)) - && (TREE_CODE (arg1) == NOP_EXPR - || TREE_CODE (arg1) == CONVERT_EXPR) - && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR - && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0))) - return - build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type, - convert (TREE_TYPE (arg0), - build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0, - TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))), - convert (TREE_TYPE (arg0), integer_zero_node)); - - /* Simplify comparison of something with itself. (For IEEE - floating-point, we can only do some of these simplifications.) */ - if (operand_equal_p (arg0, arg1, 0)) - { - switch (code) - { - case EQ_EXPR: - case GE_EXPR: - case LE_EXPR: - if (INTEGRAL_TYPE_P (TREE_TYPE (arg0))) - { - if (type == integer_type_node) - return integer_one_node; - - t = build_int_2 (1, 0); - TREE_TYPE (t) = type; - return t; - } - code = EQ_EXPR; - TREE_SET_CODE (t, code); - break; - - case NE_EXPR: - /* For NE, we can only do this simplification if integer. */ - if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))) - break; - /* ... fall through ... */ - case GT_EXPR: - case LT_EXPR: - if (type == integer_type_node) - return integer_zero_node; - - t = build_int_2 (0, 0); - TREE_TYPE (t) = type; - return t; - } - } - - /* An unsigned comparison against 0 can be simplified. */ - if (integer_zerop (arg1) - && (INTEGRAL_TYPE_P (TREE_TYPE (arg1)) - || TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE) - && TREE_UNSIGNED (TREE_TYPE (arg1))) - { - switch (TREE_CODE (t)) - { - case GT_EXPR: - code = NE_EXPR; - TREE_SET_CODE (t, NE_EXPR); - break; - case LE_EXPR: - code = EQ_EXPR; - TREE_SET_CODE (t, EQ_EXPR); - break; - case GE_EXPR: - return omit_one_operand (type, - convert (type, integer_one_node), - arg0); - case LT_EXPR: - return omit_one_operand (type, - convert (type, integer_zero_node), - arg0); - } - } - - /* If we are comparing an expression that just has comparisons - of two integer values, arithmetic expressions of those comparisons, - and constants, we can simplify it. There are only three cases - to check: the two values can either be equal, the first can be - greater, or the second can be greater. Fold the expression for - those three values. Since each value must be 0 or 1, we have - eight possibilities, each of which corresponds to the constant 0 - or 1 or one of the six possible comparisons. - - This handles common cases like (a > b) == 0 but also handles - expressions like ((x > y) - (y > x)) > 0, which supposedly - occur in macroized code. */ - - if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST) - { - tree cval1 = 0, cval2 = 0; - int save_p = 0; - - if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p) - /* Don't handle degenerate cases here; they should already - have been handled anyway. */ - && cval1 != 0 && cval2 != 0 - && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2)) - && TREE_TYPE (cval1) == TREE_TYPE (cval2) - && INTEGRAL_TYPE_P (TREE_TYPE (cval1)) - && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)), - TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0)) - { - tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1)); - tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1)); - - /* We can't just pass T to eval_subst in case cval1 or cval2 - was the same as ARG1. */ - - tree high_result - = fold (build (code, type, - eval_subst (arg0, cval1, maxval, cval2, minval), - arg1)); - tree equal_result - = fold (build (code, type, - eval_subst (arg0, cval1, maxval, cval2, maxval), - arg1)); - tree low_result - = fold (build (code, type, - eval_subst (arg0, cval1, minval, cval2, maxval), - arg1)); - - /* All three of these results should be 0 or 1. Confirm they - are. Then use those values to select the proper code - to use. */ - - if ((integer_zerop (high_result) - || integer_onep (high_result)) - && (integer_zerop (equal_result) - || integer_onep (equal_result)) - && (integer_zerop (low_result) - || integer_onep (low_result))) - { - /* Make a 3-bit mask with the high-order bit being the - value for `>', the next for '=', and the low for '<'. */ - switch ((integer_onep (high_result) * 4) - + (integer_onep (equal_result) * 2) - + integer_onep (low_result)) - { - case 0: - /* Always false. */ - return omit_one_operand (type, integer_zero_node, arg0); - case 1: - code = LT_EXPR; - break; - case 2: - code = EQ_EXPR; - break; - case 3: - code = LE_EXPR; - break; - case 4: - code = GT_EXPR; - break; - case 5: - code = NE_EXPR; - break; - case 6: - code = GE_EXPR; - break; - case 7: - /* Always true. */ - return omit_one_operand (type, integer_one_node, arg0); - } - - t = build (code, type, cval1, cval2); - if (save_p) - return save_expr (t); - else - return fold (t); - } - } - } - - /* If this is a comparison of a field, we may be able to simplify it. */ - if ((TREE_CODE (arg0) == COMPONENT_REF - || TREE_CODE (arg0) == BIT_FIELD_REF) - && (code == EQ_EXPR || code == NE_EXPR) - /* Handle the constant case even without -O - to make sure the warnings are given. */ - && (optimize || TREE_CODE (arg1) == INTEGER_CST)) - { - t1 = optimize_bit_field_compare (code, type, arg0, arg1); - return t1 ? t1 : t; - } - - /* If this is a comparison of complex values and either or both - sizes are a COMPLEX_EXPR, it is best to split up the comparisons - and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. This - may prevent needless evaluations. */ - if ((code == EQ_EXPR || code == NE_EXPR) - && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE - && (TREE_CODE (arg0) == COMPLEX_EXPR - || TREE_CODE (arg1) == COMPLEX_EXPR)) - { - tree subtype = TREE_TYPE (TREE_TYPE (arg0)); - tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0)); - tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0)); - tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1)); - tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1)); - - return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR - : TRUTH_ORIF_EXPR), - type, - fold (build (code, type, real0, real1)), - fold (build (code, type, imag0, imag1)))); - } - - /* From here on, the only cases we handle are when the result is - known to be a constant. - - To compute GT, swap the arguments and do LT. - To compute GE, do LT and invert the result. - To compute LE, swap the arguments, do LT and invert the result. - To compute NE, do EQ and invert the result. - - Therefore, the code below must handle only EQ and LT. */ - - if (code == LE_EXPR || code == GT_EXPR) - { - tem = arg0, arg0 = arg1, arg1 = tem; - code = swap_tree_comparison (code); - } - - /* Note that it is safe to invert for real values here because we - will check below in the one case that it matters. */ - - invert = 0; - if (code == NE_EXPR || code == GE_EXPR) - { - invert = 1; - code = invert_tree_comparison (code); - } - - /* Compute a result for LT or EQ if args permit; - otherwise return T. */ - if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) - { - if (code == EQ_EXPR) - t1 = build_int_2 ((TREE_INT_CST_LOW (arg0) - == TREE_INT_CST_LOW (arg1)) - && (TREE_INT_CST_HIGH (arg0) - == TREE_INT_CST_HIGH (arg1)), - 0); - else - t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0)) - ? INT_CST_LT_UNSIGNED (arg0, arg1) - : INT_CST_LT (arg0, arg1)), - 0); - } - -#if 0 /* This is no longer useful, but breaks some real code. */ - /* Assume a nonexplicit constant cannot equal an explicit one, - since such code would be undefined anyway. - Exception: on sysvr4, using #pragma weak, - a label can come out as 0. */ - else if (TREE_CODE (arg1) == INTEGER_CST - && !integer_zerop (arg1) - && TREE_CONSTANT (arg0) - && TREE_CODE (arg0) == ADDR_EXPR - && code == EQ_EXPR) - t1 = build_int_2 (0, 0); -#endif - /* Two real constants can be compared explicitly. */ - else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST) - { - /* If either operand is a NaN, the result is false with two - exceptions: First, an NE_EXPR is true on NaNs, but that case - is already handled correctly since we will be inverting the - result for NE_EXPR. Second, if we had inverted a LE_EXPR - or a GE_EXPR into a LT_EXPR, we must return true so that it - will be inverted into false. */ - - if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0)) - || REAL_VALUE_ISNAN (TREE_REAL_CST (arg1))) - t1 = build_int_2 (invert && code == LT_EXPR, 0); - - else if (code == EQ_EXPR) - t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0), - TREE_REAL_CST (arg1)), - 0); - else - t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0), - TREE_REAL_CST (arg1)), - 0); - } - - if (t1 == NULL_TREE) - return t; - - if (invert) - TREE_INT_CST_LOW (t1) ^= 1; - - TREE_TYPE (t1) = type; - return t1; - - case COND_EXPR: - /* Pedantic ANSI C says that a conditional expression is never an lvalue, - so all simple results must be passed through pedantic_non_lvalue. */ - if (TREE_CODE (arg0) == INTEGER_CST) - return pedantic_non_lvalue - (TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1))); - else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0)) - return pedantic_omit_one_operand (type, arg1, arg0); - - /* If the second operand is zero, invert the comparison and swap - the second and third operands. Likewise if the second operand - is constant and the third is not or if the third operand is - equivalent to the first operand of the comparison. */ - - if (integer_zerop (arg1) - || (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2))) - || (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<' - && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), - TREE_OPERAND (t, 2), - TREE_OPERAND (arg0, 1)))) - { - /* See if this can be inverted. If it can't, possibly because - it was a floating-point inequality comparison, don't do - anything. */ - tem = invert_truthvalue (arg0); - - if (TREE_CODE (tem) != TRUTH_NOT_EXPR) - { - t = build (code, type, tem, - TREE_OPERAND (t, 2), TREE_OPERAND (t, 1)); - arg0 = tem; - arg1 = TREE_OPERAND (t, 2); - STRIP_NOPS (arg1); - } - } - - /* If we have A op B ? A : C, we may be able to convert this to a - simpler expression, depending on the operation and the values - of B and C. IEEE floating point prevents this though, - because A or B might be -0.0 or a NaN. */ - - if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<' - && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT - || ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0))) - || flag_fast_math) - && operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0), - arg1, TREE_OPERAND (arg0, 1))) - { - tree arg2 = TREE_OPERAND (t, 2); - enum tree_code comp_code = TREE_CODE (arg0); - - STRIP_NOPS (arg2); - - /* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A), - depending on the comparison operation. */ - if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1))) - ? real_zerop (TREE_OPERAND (arg0, 1)) - : integer_zerop (TREE_OPERAND (arg0, 1))) - && TREE_CODE (arg2) == NEGATE_EXPR - && operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0)) - switch (comp_code) - { - case EQ_EXPR: - return pedantic_non_lvalue - (fold (build1 (NEGATE_EXPR, type, arg1))); - case NE_EXPR: - return pedantic_non_lvalue (convert (type, arg1)); - case GE_EXPR: - case GT_EXPR: - return pedantic_non_lvalue - (convert (type, fold (build1 (ABS_EXPR, - TREE_TYPE (arg1), arg1)))); - case LE_EXPR: - case LT_EXPR: - return pedantic_non_lvalue - (fold (build1 (NEGATE_EXPR, type, - convert (type, - fold (build1 (ABS_EXPR, - TREE_TYPE (arg1), - arg1)))))); - } - - /* If this is A != 0 ? A : 0, this is simply A. For ==, it is - always zero. */ - - if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2)) - { - if (comp_code == NE_EXPR) - return pedantic_non_lvalue (convert (type, arg1)); - else if (comp_code == EQ_EXPR) - return pedantic_non_lvalue (convert (type, integer_zero_node)); - } - - /* If this is A op B ? A : B, this is either A, B, min (A, B), - or max (A, B), depending on the operation. */ - - if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1), - arg2, TREE_OPERAND (arg0, 0))) - { - tree comp_op0 = TREE_OPERAND (arg0, 0); - tree comp_op1 = TREE_OPERAND (arg0, 1); - tree comp_type = TREE_TYPE (comp_op0); - - switch (comp_code) - { - case EQ_EXPR: - return pedantic_non_lvalue (convert (type, arg2)); - case NE_EXPR: - return pedantic_non_lvalue (convert (type, arg1)); - case LE_EXPR: - case LT_EXPR: - return pedantic_non_lvalue - (convert (type, (fold (build (MIN_EXPR, comp_type, - comp_op0, comp_op1))))); - case GE_EXPR: - case GT_EXPR: - return pedantic_non_lvalue - (convert (type, fold (build (MAX_EXPR, comp_type, - comp_op0, comp_op1)))); - } - } - - /* If this is A op C1 ? A : C2 with C1 and C2 constant integers, - we might still be able to simplify this. For example, - if C1 is one less or one more than C2, this might have started - out as a MIN or MAX and been transformed by this function. - Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */ - - if (INTEGRAL_TYPE_P (type) - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST - && TREE_CODE (arg2) == INTEGER_CST) - switch (comp_code) - { - case EQ_EXPR: - /* We can replace A with C1 in this case. */ - arg1 = convert (type, TREE_OPERAND (arg0, 1)); - t = build (code, type, TREE_OPERAND (t, 0), arg1, - TREE_OPERAND (t, 2)); - break; - - case LT_EXPR: - /* If C1 is C2 + 1, this is min(A, C2). */ - if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1) - && operand_equal_p (TREE_OPERAND (arg0, 1), - const_binop (PLUS_EXPR, arg2, - integer_one_node, 0), 1)) - return pedantic_non_lvalue - (fold (build (MIN_EXPR, type, arg1, arg2))); - break; - - case LE_EXPR: - /* If C1 is C2 - 1, this is min(A, C2). */ - if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1) - && operand_equal_p (TREE_OPERAND (arg0, 1), - const_binop (MINUS_EXPR, arg2, - integer_one_node, 0), 1)) - return pedantic_non_lvalue - (fold (build (MIN_EXPR, type, arg1, arg2))); - break; - - case GT_EXPR: - /* If C1 is C2 - 1, this is max(A, C2). */ - if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1) - && operand_equal_p (TREE_OPERAND (arg0, 1), - const_binop (MINUS_EXPR, arg2, - integer_one_node, 0), 1)) - return pedantic_non_lvalue - (fold (build (MAX_EXPR, type, arg1, arg2))); - break; - - case GE_EXPR: - /* If C1 is C2 + 1, this is max(A, C2). */ - if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1) - && operand_equal_p (TREE_OPERAND (arg0, 1), - const_binop (PLUS_EXPR, arg2, - integer_one_node, 0), 1)) - return pedantic_non_lvalue - (fold (build (MAX_EXPR, type, arg1, arg2))); - break; - } - } - - /* If the second operand is simpler than the third, swap them - since that produces better jump optimization results. */ - if ((TREE_CONSTANT (arg1) || TREE_CODE_CLASS (TREE_CODE (arg1)) == 'd' - || TREE_CODE (arg1) == SAVE_EXPR) - && ! (TREE_CONSTANT (TREE_OPERAND (t, 2)) - || TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 2))) == 'd' - || TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR)) - { - /* See if this can be inverted. If it can't, possibly because - it was a floating-point inequality comparison, don't do - anything. */ - tem = invert_truthvalue (arg0); - - if (TREE_CODE (tem) != TRUTH_NOT_EXPR) - { - t = build (code, type, tem, - TREE_OPERAND (t, 2), TREE_OPERAND (t, 1)); - arg0 = tem; - arg1 = TREE_OPERAND (t, 2); - STRIP_NOPS (arg1); - } - } - - /* Convert A ? 1 : 0 to simply A. */ - if (integer_onep (TREE_OPERAND (t, 1)) - && integer_zerop (TREE_OPERAND (t, 2)) - /* If we try to convert TREE_OPERAND (t, 0) to our type, the - call to fold will try to move the conversion inside - a COND, which will recurse. In that case, the COND_EXPR - is probably the best choice, so leave it alone. */ - && type == TREE_TYPE (arg0)) - return pedantic_non_lvalue (arg0); - - /* Look for expressions of the form A & 2 ? 2 : 0. The result of this - operation is simply A & 2. */ - - if (integer_zerop (TREE_OPERAND (t, 2)) - && TREE_CODE (arg0) == NE_EXPR - && integer_zerop (TREE_OPERAND (arg0, 1)) - && integer_pow2p (arg1) - && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR - && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1), - arg1, 1)) - return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0))); - - return t; - - case COMPOUND_EXPR: - /* When pedantic, a compound expression can be neither an lvalue - nor an integer constant expression. */ - if (TREE_SIDE_EFFECTS (arg0) || pedantic) - return t; - /* Don't let (0, 0) be null pointer constant. */ - if (integer_zerop (arg1)) - return non_lvalue (arg1); - return arg1; - - case COMPLEX_EXPR: - if (wins) - return build_complex (type, arg0, arg1); - return t; - - case REALPART_EXPR: - if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) - return t; - else if (TREE_CODE (arg0) == COMPLEX_EXPR) - return omit_one_operand (type, TREE_OPERAND (arg0, 0), - TREE_OPERAND (arg0, 1)); - else if (TREE_CODE (arg0) == COMPLEX_CST) - return TREE_REALPART (arg0); - else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) - return fold (build (TREE_CODE (arg0), type, - fold (build1 (REALPART_EXPR, type, - TREE_OPERAND (arg0, 0))), - fold (build1 (REALPART_EXPR, - type, TREE_OPERAND (arg0, 1))))); - return t; - - case IMAGPART_EXPR: - if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE) - return convert (type, integer_zero_node); - else if (TREE_CODE (arg0) == COMPLEX_EXPR) - return omit_one_operand (type, TREE_OPERAND (arg0, 1), - TREE_OPERAND (arg0, 0)); - else if (TREE_CODE (arg0) == COMPLEX_CST) - return TREE_IMAGPART (arg0); - else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) - return fold (build (TREE_CODE (arg0), type, - fold (build1 (IMAGPART_EXPR, type, - TREE_OPERAND (arg0, 0))), - fold (build1 (IMAGPART_EXPR, type, - TREE_OPERAND (arg0, 1))))); - return t; - - /* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where - appropriate. */ - case CLEANUP_POINT_EXPR: - if (! TREE_SIDE_EFFECTS (arg0)) - return TREE_OPERAND (t, 0); - - { - enum tree_code code0 = TREE_CODE (arg0); - int kind0 = TREE_CODE_CLASS (code0); - tree arg00 = TREE_OPERAND (arg0, 0); - tree arg01; - - if (kind0 == '1' || code0 == TRUTH_NOT_EXPR) - return fold (build1 (code0, type, - fold (build1 (CLEANUP_POINT_EXPR, - TREE_TYPE (arg00), arg00)))); - - if (kind0 == '<' || kind0 == '2' - || code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR - || code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR - || code0 == TRUTH_XOR_EXPR) - { - arg01 = TREE_OPERAND (arg0, 1); - - if (! TREE_SIDE_EFFECTS (arg00)) - return fold (build (code0, type, arg00, - fold (build1 (CLEANUP_POINT_EXPR, - TREE_TYPE (arg01), arg01)))); - - if (! TREE_SIDE_EFFECTS (arg01)) - return fold (build (code0, type, - fold (build1 (CLEANUP_POINT_EXPR, - TREE_TYPE (arg00), arg00)), - arg01)); - } - - return t; - } - - default: - return t; - } /* switch (code) */ -} |