OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

re PR tree-optimization/31522 (False overflow warning with phi nodes) 

./:	PR tree-optimization/31522
	* tree-vrp.c (vr_phi_edge_counts): New static variable.
	(vrp_initialize): Allocate vr_phi_edge_counts.
	(vrp_visit_phi_node): Don't push to infinity if we saw a new
	executable edge.  Drop test for all constants.
	(vrp_finalize): Free vrp_phi_edge_counts.
testsuite/:
	PR tree-optimization/31522
	* gcc.dg/Wstrict-overflow-16.c: New test.

From-SVN: r123908
This commit is contained in:
Ian Lance Taylor 2007-04-17 05:33:38 +00:00 committed by Ian Lance Taylor
parent 4075e23198
commit fc6827fe9f
4 changed files with 42 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gcc/ChangeLog
View File

@ -1,5 +1,12 @@
2007-04-16 Ian Lance Taylor <iant@google.com>
PR tree-optimization/31522
* tree-vrp.c (vr_phi_edge_counts): New static variable.
(vrp_initialize): Allocate vr_phi_edge_counts.
(vrp_visit_phi_node): Don't push to infinity if we saw a new
executable edge. Drop test for all constants.
(vrp_finalize): Free vrp_phi_edge_counts.
* doc/cpp.texi (Common Predefined Macros): Clarify description of
__GNUC_GNU_INLINE__ and __GNUC_STDC_INLINE__.

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2007-04-16 Ian Lance Taylor <iant@google.com>
PR tree-optimization/31522
* gcc.dg/Wstrict-overflow-16.c: New test.
2007-04-17 Kazu Hirata <kazu@codesourcery.com>
* gcc.dg/cpp/_Pragma6.c: Skip on fido-*-* and m68k-*-*.

11
gcc/testsuite/gcc.dg/Wstrict-overflow-16.c Normal file
View File

@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-fstrict-overflow -O2 -Wstrict-overflow" } */
/* From PR 31522. */
int f (int x) {
int y;
if (x <= 4) y = 1;
else y = x / 4;
return y <= 0;
}

23
gcc/tree-vrp.c
View File

@ -95,6 +95,11 @@ static sbitmap blocks_visited;
of values that SSA name N_I may take. */
static value_range_t **vr_value;
/* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
number of executable edges we saw the last time we visited the
node. */
static int *vr_phi_edge_counts;
/* Return whether TYPE should use an overflow infinity distinct from
TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
@ -4433,6 +4438,7 @@ vrp_initialize (void)
basic_block bb;
vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
FOR_EACH_BB (bb)
{
@ -5185,7 +5191,7 @@ vrp_visit_phi_node (tree phi)
tree lhs = PHI_RESULT (phi);
value_range_t *lhs_vr = get_value_range (lhs);
value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
bool all_const = true;
int edges, old_edges;
copy_value_range (&vr_result, lhs_vr);
@ -5195,6 +5201,7 @@ vrp_visit_phi_node (tree phi)
print_generic_expr (dump_file, phi, dump_flags);
}
edges = 0;
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
{
edge e = PHI_ARG_EDGE (phi, i);
@ -5212,10 +5219,11 @@ vrp_visit_phi_node (tree phi)
tree arg = PHI_ARG_DEF (phi, i);
value_range_t vr_arg;
++edges;
if (TREE_CODE (arg) == SSA_NAME)
{
vr_arg = *(get_value_range (arg));
all_const = false;
}
else
{
@ -5244,11 +5252,16 @@ vrp_visit_phi_node (tree phi)
if (vr_result.type == VR_VARYING)
goto varying;
old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
/* To prevent infinite iterations in the algorithm, derive ranges
when the new value is slightly bigger or smaller than the
previous one. */
previous one. We don't do this if we have seen a new executable
edge; this helps us avoid an overflow infinity for conditionals
which are not in a loop. */
if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
&& !all_const)
&& edges <= old_edges)
{
if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
{
@ -5827,10 +5840,12 @@ vrp_finalize (void)
free (single_val_range);
free (vr_value);
free (vr_phi_edge_counts);
/* So that we can distinguish between VRP data being available
and not available. */
vr_value = NULL;
vr_phi_edge_counts = NULL;
}