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Don't fold equality comparisons with constants if the operand is larger than 

the word size.
This commit is contained in:
mycroft 1998-11-10 18:51:45 +00:00
parent eba40aeea0
commit 246ed829a5
1 changed files with 11 additions and 6 deletions
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17
gnu/usr.bin/gcc/common/combine.c
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@ -8863,8 +8863,9 @@ simplify_comparison (code, pop0, pop1)
}
/* If the first operand is a constant, swap the operands and adjust the
comparison code appropriately. */
if (CONSTANT_P (op0))
comparison code appropriately, but don't do this if the second operand
is already a constant integer. */
if (CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT)
{
tem = op0, op0 = op1, op1 = tem;
code = swap_condition (code);
@ -9006,7 +9007,8 @@ simplify_comparison (code, pop0, pop1)
}
/* (unsigned) < 0x80000000 is equivalent to >= 0. */
else if (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1))
else if ((mode_width <= HOST_BITS_PER_WIDE_INT)
&& (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1)))
{
const_op = 0, op1 = const0_rtx;
code = GE;
@ -9021,7 +9023,8 @@ simplify_comparison (code, pop0, pop1)
code = EQ;
/* (unsigned) <= 0x7fffffff is equivalent to >= 0. */
else if (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
else if ((mode_width <= HOST_BITS_PER_WIDE_INT)
&& (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1))
{
const_op = 0, op1 = const0_rtx;
code = GE;
@ -9039,7 +9042,8 @@ simplify_comparison (code, pop0, pop1)
}
/* (unsigned) >= 0x80000000 is equivalent to < 0. */
else if (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1))
else if ((mode_width <= HOST_BITS_PER_WIDE_INT)
&& (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1)))
{
const_op = 0, op1 = const0_rtx;
code = LT;
@ -9054,7 +9058,8 @@ simplify_comparison (code, pop0, pop1)
code = NE;
/* (unsigned) > 0x7fffffff is equivalent to < 0. */
else if (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1)
else if ((mode_width <= HOST_BITS_PER_WIDE_INT)
&& (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1))
{
const_op = 0, op1 = const0_rtx;
code = LT;