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re PR middle-end/26561 (ACATS failures c34004a, c46033a and cxg2024 at -O0) 

2006-03-09  Roger Sayle  <roger@eyesopen.com>
	    Eric Botcazou  <ebotcazou@libertysurf.fr>

	PR middle-end/26561
	* fold-const.c (fold_div_compare): When optimizing X/C1 op C2 as
	X op C3, consider whether C3 overflows towards +Inf or -Inf.

	* gcc.c-torture/execute/divcmp-5.c: New test case.


Co-Authored-By: Eric Botcazou <ebotcazou@libertysurf.fr>

From-SVN: r111862
This commit is contained in:
Roger Sayle 2006-03-09 14:54:11 +00:00 committed by Roger Sayle
parent ad5dd90de0
commit d56ee62bfe
4 changed files with 64 additions and 5 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2006-03-09 Roger Sayle <roger@eyesopen.com>
PR middle-end/26561
* fold-const.c (fold_div_compare): When optimizing X/C1 op C2 as
X op C3, consider whether C3 overflows towards +Inf or -Inf.
2006-03-08 DJ Delorie <dj@redhat.com>
* config/m32c/addsub.md (addqi3): Disparage a0/a1.

26
gcc/fold-const.c
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@ -6014,6 +6014,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
tree arg01 = TREE_OPERAND (arg0, 1);
unsigned HOST_WIDE_INT lpart;
HOST_WIDE_INT hpart;
bool neg_overflow;
int overflow;
/* We have to do this the hard way to detect unsigned overflow.
@ -6024,6 +6025,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
TREE_INT_CST_HIGH (arg1), &lpart, &hpart);
prod = build_int_cst_wide (TREE_TYPE (arg00), lpart, hpart);
prod = force_fit_type (prod, -1, overflow, false);
neg_overflow = false;
if (TYPE_UNSIGNED (TREE_TYPE (arg0)))
{
@ -6046,6 +6048,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
switch (tree_int_cst_sgn (arg1))
{
case -1:
neg_overflow = true;
lo = int_const_binop (MINUS_EXPR, prod, tmp, 0);
hi = prod;
break;
@ -6083,7 +6086,8 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
break;
case 1:
lo = int_const_binop (PLUS_EXPR, prod, tmp, 0);
neg_overflow = true;
lo = int_const_binop (PLUS_EXPR, prod, tmp, 0);
hi = prod;
break;
@ -6114,22 +6118,34 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
case LT_EXPR:
if (TREE_OVERFLOW (lo))
return omit_one_operand (type, integer_one_node, arg00);
{
tmp = neg_overflow ? integer_zero_node : integer_one_node;
return omit_one_operand (type, tmp, arg00);
}
return fold_build2 (LT_EXPR, type, arg00, lo);
case LE_EXPR:
if (TREE_OVERFLOW (hi))
return omit_one_operand (type, integer_one_node, arg00);
{
tmp = neg_overflow ? integer_zero_node : integer_one_node;
return omit_one_operand (type, tmp, arg00);
}
return fold_build2 (LE_EXPR, type, arg00, hi);
case GT_EXPR:
if (TREE_OVERFLOW (hi))
return omit_one_operand (type, integer_zero_node, arg00);
{
tmp = neg_overflow ? integer_one_node : integer_zero_node;
return omit_one_operand (type, tmp, arg00);
}
return fold_build2 (GT_EXPR, type, arg00, hi);
case GE_EXPR:
if (TREE_OVERFLOW (lo))
return omit_one_operand (type, integer_zero_node, arg00);
{
tmp = neg_overflow ? integer_one_node : integer_zero_node;
return omit_one_operand (type, tmp, arg00);
}
return fold_build2 (GE_EXPR, type, arg00, lo);
default:

6
gcc/testsuite/ChangeLog
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@ -1,3 +1,9 @@
2006-03-09 Roger Sayle <roger@eyesopen.com>
Eric Botcazou <ebotcazou@libertysurf.fr>
PR middle-end/26561
* gcc.c-torture/execute/divcmp-5.c: New test case.
2006-03-09 Paul Thomas <pault@gcc.gnu.org>
* PR fortran/26257

31
gcc/testsuite/gcc.c-torture/execute/divcmp-5.c Normal file
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@ -0,0 +1,31 @@
/* PR middle-end/26561 */
extern void abort(void);
int always_one_1 (int a)
{
if (a/100 >= -999999999)
return 1;
else
return 0;
}
int always_one_2 (int a)
{
if (a/100 < -999999999)
return 0;
else
return 1;
}
int main(void)
{
if (always_one_1 (0) != 1)
abort ();
if (always_one_2 (0) != 1)
abort ();
return 0;
}