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re PR tree-optimization/57124 (254.gap@spec2000 got miscompare after r198413)

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PR tree-optimization/57124
	* tree-vrp.c (simplify_cond_using_ranges): Only simplify a
	conversion feeding a condition if the range has an overflow
	if -fstrict-overflow.  Add warnings for when we do make the
	transformation.

	PR tree-optimization/57124
	* gcc.c-torture/execute/pr57124.c: New test.
	* gcc.c-torture/execute/pr57124.x: Set -fno-strict-overflow.

From-SVN: r199305
This commit is contained in:
Jeff Law 2013-05-24 11:13:38 -06:00 committed by Jeff Law
parent dd1c676f75
commit 2343af6558
5 changed files with 68 additions and 1 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2013-05-24 Jeff Law <law@redhat.com>
PR tree-optimization/57124
* tree-vrp.c (simplify_cond_using_ranges): Only simplify a
conversion feeding a condition if the range has an overflow
if -fstrict-overflow. Add warnings for when we do make the
transformation.
2013-05-24 Dehao Chen <dehao@google.com>
* gcc/tree-cfg.c (locus_discrim_map): Fix the typo.

6
gcc/testsuite/ChangeLog
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@ -1,3 +1,9 @@
2013-05-24 Jeff Law <law@redhat.com>
PR tree-optimization/57124
* gcc.c-torture/execute/pr57124.c: New test.
* gcc.c-torture/execute/pr57124.x: Set -fno-strict-overflow.
2013-05-24 Martin Jambor <mjambor@suse.cz>
PR tree-optimization/57294

27
gcc/testsuite/gcc.c-torture/execute/pr57124.c Normal file
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@ -0,0 +1,27 @@
__attribute__ ((noinline))
foo(short unsigned int *p1, short unsigned int *p2)
{
short unsigned int x1, x4;
int x2, x3, x5, x6;
unsigned int x7;
x1 = *p1;
x2 = (int) x1;
x3 = x2 * 65536;
x4 = *p2;
x5 = (int) x4;
x6 = x3 + x4;
x7 = (unsigned int) x6;
if (x7 <= 268435455U)
abort ();
exit (0);
}
main()
{
short unsigned int x, y;
x = -5;
y = -10;
foo (&x, &y);
}

2
gcc/testsuite/gcc.c-torture/execute/pr57124.x Normal file
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@ -0,0 +1,2 @@
set additional_flags "-fno-strict-overflow"
return 0

26
gcc/tree-vrp.c
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@ -8670,8 +8670,32 @@ simplify_cond_using_ranges (gimple stmt)
&& range_fits_type_p (vr,
TYPE_PRECISION (TREE_TYPE (op0)),
TYPE_UNSIGNED (TREE_TYPE (op0)))
&& int_fits_type_p (op1, TREE_TYPE (innerop)))
&& int_fits_type_p (op1, TREE_TYPE (innerop))
/* The range must not have overflowed, or if it did overflow
we must not be wrapping/trapping overflow and optimizing
with strict overflow semantics. */
&& ((!is_negative_overflow_infinity (vr->min)
&& !is_positive_overflow_infinity (vr->max))
|| TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (innerop))))
{
/* If the range overflowed and the user has asked for warnings
when strict overflow semantics were used to optimize code,
issue an appropriate warning. */
if ((is_negative_overflow_infinity (vr->min)
|| is_positive_overflow_infinity (vr->max))
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_CONDITIONAL))
{
location_t location;
if (!gimple_has_location (stmt))
location = input_location;
else
location = gimple_location (stmt);
warning_at (location, OPT_Wstrict_overflow,
"assuming signed overflow does not occur when "
"simplifying conditional");
}
tree newconst = fold_convert (TREE_TYPE (innerop), op1);
gimple_cond_set_lhs (stmt, innerop);
gimple_cond_set_rhs (stmt, newconst);