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gnu / gcc / 737cee66f221eb8de21f0e41affc4b13cb7c0feb / . / gcc / fold-const.c
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/* 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, size_binop
and force_fit_type.
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'.
force_fit_type takes a constant and prior overflow indicator, and
forces the value to fit the type. It returns an overflow indicator. */
#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, &ltwice, &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_CONSTANT_OVERFLOW (arg0)
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& TREE_INT_CST_LOW (arg0) == TREE_INT_CST_LOW (arg1)
&& TREE_INT_CST_HIGH (arg0) == TREE_INT_CST_HIGH (arg1));
case REAL_CST:
return (! TREE_CONSTANT_OVERFLOW (arg0)
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& 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);
}
}