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re PR tree-optimization/31605 (VRP eliminates a useful test due with conversion from unsigned int to int)

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./:	PR tree-optimization/31605
	* tree-vrp.c (set_value_range): Check that min and max are not
	both overflow infinities.
	(set_value_range_to_value): New static function.
	(extract_range_from_binary_expr): Call set_value_range_to_value.
	(extract_range_from_cond_expr): Likewise.
	(extract_range_from_expr): Likewise.
	(extract_range_from_unary_expr): Likewise.  Don't create a range
	which overflows on both sides.
	(vrp_meet): Check for a useless range.
	(vrp_visit_phi_node): If we see a constant which looks like an
	overflow infinity, turn off the TREE_OVERFLOW flag.
testsuite/:
	PR tree-optimizatoin/31605
	* gcc.c-torture/execute/pr31605.c: New test.

From-SVN: r124128
This commit is contained in:
Ian Lance Taylor 2007-04-24 22:24:01 +00:00 committed by Ian Lance Taylor
parent 1e9ecf6da4
commit 8cf781f088
4 changed files with 89 additions and 7 deletions
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15
gcc/ChangeLog
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@ -1,3 +1,18 @@
2007-04-24 Ian Lance Taylor <iant@google.com>
PR tree-optimization/31605
* tree-vrp.c (set_value_range): Check that min and max are not
both overflow infinities.
(set_value_range_to_value): New static function.
(extract_range_from_binary_expr): Call set_value_range_to_value.
(extract_range_from_cond_expr): Likewise.
(extract_range_from_expr): Likewise.
(extract_range_from_unary_expr): Likewise. Don't create a range
which overflows on both sides.
(vrp_meet): Check for a useless range.
(vrp_visit_phi_node): If we see a constant which looks like an
overflow infinity, turn off the TREE_OVERFLOW flag.
2007-04-24 Ian Lance Taylor <iant@google.com>
* flow.c (elim_reg_cond): Handle a comparison of a subreg.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2007-04-24 Ian Lance Taylor <iant@google.com>
PR tree-optimizatoin/31605
* gcc.c-torture/execute/pr31605.c: New test.
2007-04-24 Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
PR fortran/31587

13
gcc/testsuite/gcc.c-torture/execute/pr31605.c Normal file
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@ -0,0 +1,13 @@
void put_field (unsigned int start, unsigned int len)
{
int cur_bitshift = ((start + len) % 8) - 8;
if (cur_bitshift > -8)
exit (0);
}
int
main ()
{
put_field (0, 1);
abort ();
}

63
gcc/tree-vrp.c
View File

@ -272,6 +272,10 @@ set_value_range (value_range_t *vr, enum value_range_type t, tree min,
cmp = compare_values (min, max);
gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
if (needs_overflow_infinity (TREE_TYPE (min)))
gcc_assert (!is_overflow_infinity (min)
|| !is_overflow_infinity (max));
}
if (t == VR_UNDEFINED || t == VR_VARYING)
@ -320,6 +324,23 @@ set_value_range_to_varying (value_range_t *vr)
bitmap_clear (vr->equiv);
}
/* Set value range VR to a single value. This function is only called
with values we get from statements, and exists to clear the
TREE_OVERFLOW flag so that we don't think we have an overflow
infinity when we shouldn't. */
static inline void
set_value_range_to_value (value_range_t *vr, tree val)
{
gcc_assert (is_gimple_min_invariant (val));
if (is_overflow_infinity (val))
{
val = copy_node (val);
TREE_OVERFLOW (val) = 0;
}
set_value_range (vr, VR_RANGE, val, val, NULL);
}
/* Set value range VR to a non-negative range of type TYPE.
OVERFLOW_INFINITY indicates whether to use a overflow infinity
rather than TYPE_MAX_VALUE; this should be true if we determine
@ -1646,7 +1667,7 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr)
if (TREE_CODE (op0) == SSA_NAME)
vr0 = *(get_value_range (op0));
else if (is_gimple_min_invariant (op0))
set_value_range (&vr0, VR_RANGE, op0, op0, NULL);
set_value_range_to_value (&vr0, op0);
else
set_value_range_to_varying (&vr0);
@ -1654,7 +1675,7 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr)
if (TREE_CODE (op1) == SSA_NAME)
vr1 = *(get_value_range (op1));
else if (is_gimple_min_invariant (op1))
set_value_range (&vr1, VR_RANGE, op1, op1, NULL);
set_value_range_to_value (&vr1, op1);
else
set_value_range_to_varying (&vr1);
@ -2053,7 +2074,7 @@ extract_range_from_unary_expr (value_range_t *vr, tree expr)
if (TREE_CODE (op0) == SSA_NAME)
vr0 = *(get_value_range (op0));
else if (is_gimple_min_invariant (op0))
set_value_range (&vr0, VR_RANGE, op0, op0, NULL);
set_value_range_to_value (&vr0, op0);
else
set_value_range_to_varying (&vr0);
@ -2185,7 +2206,9 @@ extract_range_from_unary_expr (value_range_t *vr, tree expr)
min = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.max);
else if (needs_overflow_infinity (TREE_TYPE (expr)))
{
if (supports_overflow_infinity (TREE_TYPE (expr)))
if (supports_overflow_infinity (TREE_TYPE (expr))
&& !is_overflow_infinity (vr0.min)
&& vr0.min != TYPE_MIN_VALUE (TREE_TYPE (expr)))
min = positive_overflow_infinity (TREE_TYPE (expr));
else
{
@ -2361,6 +2384,18 @@ extract_range_from_unary_expr (value_range_t *vr, tree expr)
if (needs_overflow_infinity (TREE_TYPE (expr)))
{
gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
/* If both sides have overflowed, we don't know
anything. */
if ((is_overflow_infinity (vr0.min)
|| TREE_OVERFLOW (min))
&& (is_overflow_infinity (vr0.max)
|| TREE_OVERFLOW (max)))
{
set_value_range_to_varying (vr);
return;
}
if (is_overflow_infinity (vr0.min))
min = vr0.min;
else if (TREE_OVERFLOW (min))
@ -2422,7 +2457,7 @@ extract_range_from_cond_expr (value_range_t *vr, tree expr)
if (TREE_CODE (op0) == SSA_NAME)
vr0 = *(get_value_range (op0));
else if (is_gimple_min_invariant (op0))
set_value_range (&vr0, VR_RANGE, op0, op0, NULL);
set_value_range_to_value (&vr0, op0);
else
set_value_range_to_varying (&vr0);
@ -2430,7 +2465,7 @@ extract_range_from_cond_expr (value_range_t *vr, tree expr)
if (TREE_CODE (op1) == SSA_NAME)
vr1 = *(get_value_range (op1));
else if (is_gimple_min_invariant (op1))
set_value_range (&vr1, VR_RANGE, op1, op1, NULL);
set_value_range_to_value (&vr1, op1);
else
set_value_range_to_varying (&vr1);
@ -2494,7 +2529,7 @@ extract_range_from_expr (value_range_t *vr, tree expr)
else if (TREE_CODE_CLASS (code) == tcc_comparison)
extract_range_from_comparison (vr, expr);
else if (is_gimple_min_invariant (expr))
set_value_range (vr, VR_RANGE, expr, expr, NULL);
set_value_range_to_value (vr, expr);
else
set_value_range_to_varying (vr);
@ -5106,6 +5141,14 @@ vrp_meet (value_range_t *vr0, value_range_t *vr1)
else
goto give_up;
/* Check for useless ranges. */
if (INTEGRAL_TYPE_P (TREE_TYPE (min))
&& ((min == TYPE_MIN_VALUE (TREE_TYPE (min))
|| is_overflow_infinity (min))
&& (max == TYPE_MAX_VALUE (TREE_TYPE (max))
|| is_overflow_infinity (max))))
goto give_up;
/* The resulting set of equivalences is the intersection of
the two sets. */
if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
@ -5235,6 +5278,12 @@ vrp_visit_phi_node (tree phi)
}
else
{
if (is_overflow_infinity (arg))
{
arg = copy_node (arg);
TREE_OVERFLOW (arg) = 0;
}
vr_arg.type = VR_RANGE;
vr_arg.min = arg;
vr_arg.max = arg;