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re PR tree-optimization/22026 (ACATS FAIL C45331A fixed point wrong code (VRP related))

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gcc/
	PR tree-optimization/22026
	* tree-vrp.c (extract_range_from_binary_expr): Drop to
	VR_VARYING if a binary expression involving VR_ANTI_RANGE is
	PLUS_EXPR, MINUS_EXPR, or unsigned MULT_EXPR.

testsuite/
	PR tree-optimization/22026
	* gcc.dg/tree-ssa/pr22026.c: New.

From-SVN: r101328
This commit is contained in:
Kazu Hirata 2005-06-26 03:49:20 +00:00 committed by Kazu Hirata
parent e4ca1c958e
commit 567fb6602c
4 changed files with 104 additions and 1 deletions
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9
gcc/ChangeLog
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@ -1,4 +1,11 @@
2005-06-25 Kazu Hirata <kazu@codesourcery.com>
2005-06-26 Kazu Hirata <kazu@codesourcery.com>
PR tree-optimization/22026
* tree-vrp.c (extract_range_from_binary_expr): Drop to
VR_VARYING if a binary expression involving VR_ANTI_RANGE is
PLUS_EXPR, MINUS_EXPR, or unsigned MULT_EXPR.
2005-06-26 Kazu Hirata <kazu@codesourcery.com>
* Makefile.in (OBJS-common): Remove duplicate object file
names.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2005-06-26 Kazu Hirata <kazu@codesourcery.com>
PR tree-optimization/22026
* gcc.dg/tree-ssa/pr22026.c: New.
2005-06-25 Thomas Koenig <Thomas.Koenig@online.de>
PR libfortran/21144

49
gcc/testsuite/gcc.dg/tree-ssa/pr22026.c Normal file
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@ -0,0 +1,49 @@
/* PR tree-optimization/22026
VRP used think that ~[0,0] + ~[0,0] = ~[0,0], which is wrong. The
same applies to subtraction and unsigned multiplication. */
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-vrp" } */
int
plus (int x, int y)
{
if (x != 0)
if (y != 0)
{
int z = x + y;
if (z != 0)
return 1;
}
return 0;
}
int
minus (int x, int y)
{
if (x != 0)
if (y != 0)
{
int z = x - y;
if (z != 0)
return 1;
}
return 0;
}
int
mult (unsigned x, unsigned y)
{
if (x != 0)
if (y != 0)
{
unsigned z = x * y;
if (z != 0)
return 1;
}
return 0;
}
/* None of the predicates can be folded in these functions. */
/* { dg-final { scan-tree-dump-times "Folding predicate" 0 "vrp" } } */
/* { dg-final { cleanup-tree-dump "vrp" } } */

42
gcc/tree-vrp.c
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@ -1107,6 +1107,19 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr)
|| code == MIN_EXPR
|| code == MAX_EXPR)
{
/* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
VR_VARYING. It would take more effort to compute a precise
range for such a case. For example, if we have op0 == 1 and
op1 == -1 with their ranges both being ~[0,0], we would have
op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
Note that we are guaranteed to have vr0.type == vr1.type at
this point. */
if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
{
set_value_range_to_varying (vr);
return;
}
/* For operations that make the resulting range directly
proportional to the original ranges, apply the operation to
the same end of each range. */
@ -1123,6 +1136,22 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr)
tree val[4];
size_t i;
/* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
drop to VR_VARYING. It would take more effort to compute a
precise range for such a case. For example, if we have
op0 == 65536 and op1 == 65536 with their ranges both being
~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
we cannot claim that the product is in ~[0,0]. Note that we
are guaranteed to have vr0.type == vr1.type at this
point. */
if (code == MULT_EXPR
&& vr0.type == VR_ANTI_RANGE
&& (flag_wrapv || TYPE_UNSIGNED (TREE_TYPE (op0))))
{
set_value_range_to_varying (vr);
return;
}
/* Multiplications and divisions are a bit tricky to handle,
depending on the mix of signs we have in the two ranges, we
need to operate on different values to get the minimum and
@ -1188,6 +1217,19 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr)
}
else if (code == MINUS_EXPR)
{
/* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
VR_VARYING. It would take more effort to compute a precise
range for such a case. For example, if we have op0 == 1 and
op1 == 1 with their ranges both being ~[0,0], we would have
op0 - op1 == 0, so we cannot claim that the difference is in
~[0,0]. Note that we are guaranteed to have
vr0.type == vr1.type at this point. */
if (vr0.type == VR_ANTI_RANGE)
{
set_value_range_to_varying (vr);
return;
}
/* For MINUS_EXPR, apply the operation to the opposite ends of
each range. */
min = vrp_int_const_binop (code, vr0.min, vr1.max);