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tree-vrp.c (vrp_visit_phi_node): Allow a last iteration if the currently executable edges have fixed ranges. 

2016-08-12  Richard Biener  <rguenther@suse.de>

	* tree-vrp.c (vrp_visit_phi_node): Allow a last iteration if
	the currently executable edges have fixed ranges.  Always
	go through update_value_range.

From-SVN: r239404
This commit is contained in:
Richard Biener 2016-08-12 07:29:10 +00:00 committed by Richard Biener
parent e366d7d807
commit 2650da8892
2 changed files with 43 additions and 27 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-08-12 Richard Biener <rguenther@suse.de>
* tree-vrp.c (vrp_visit_phi_node): Allow a last iteration if
the currently executable edges have fixed ranges. Always
go through update_value_range.
2016-08-12 Alexandre Oliva <aoliva@redhat.com>
PR debug/63240

64
gcc/tree-vrp.c
View File

@ -8725,6 +8725,7 @@ vrp_visit_phi_node (gphi *phi)
print_gimple_stmt (dump_file, phi, 0, dump_flags);
}
bool may_simulate_again = false;
edges = 0;
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
@ -8747,6 +8748,12 @@ vrp_visit_phi_node (gphi *phi)
if (TREE_CODE (arg) == SSA_NAME)
{
/* See if we are eventually going to change one of the args. */
gimple *def_stmt = SSA_NAME_DEF_STMT (arg);
if (! gimple_nop_p (def_stmt)
&& prop_simulate_again_p (def_stmt))
may_simulate_again = true;
vr_arg = *(get_value_range (arg));
/* Do not allow equivalences or symbolic ranges to leak in from
backedges. That creates invalid equivalencies.
@ -8822,11 +8829,14 @@ vrp_visit_phi_node (gphi *phi)
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 the old value-range was VR_UNDEFINED
use the updated range and iterate one more time. */
use the updated range and iterate one more time. If we will not
simulate this PHI again with the same number of edges then iterate
one more time. */
if (edges > 0
&& gimple_phi_num_args (phi) > 1
&& edges == old_edges
&& lhs_vr->type != VR_UNDEFINED)
&& lhs_vr->type != VR_UNDEFINED
&& may_simulate_again)
{
/* Compare old and new ranges, fall back to varying if the
values are not comparable. */
@ -8880,6 +8890,31 @@ vrp_visit_phi_node (gphi *phi)
goto infinite_check;
}
goto update_range;
varying:
set_value_range_to_varying (&vr_result);
scev_check:
/* If this is a loop PHI node SCEV may known more about its value-range.
scev_check can be reached from two paths, one is a fall through from above
"varying" label, the other is direct goto from code block which tries to
avoid infinite simulation. */
if ((l = loop_containing_stmt (phi))
&& l->header == gimple_bb (phi))
adjust_range_with_scev (&vr_result, l, phi, lhs);
infinite_check:
/* If we will end up with a (-INF, +INF) range, set it to
VARYING. Same if the previous max value was invalid for
the type and we end up with vr_result.min > vr_result.max. */
if ((vr_result.type == VR_RANGE || vr_result.type == VR_ANTI_RANGE)
&& !((vrp_val_is_max (vr_result.max) && vrp_val_is_min (vr_result.min))
|| compare_values (vr_result.min, vr_result.max) > 0))
;
else
set_value_range_to_varying (&vr_result);
/* If the new range is different than the previous value, keep
iterating. */
update_range:
@ -8902,31 +8937,6 @@ update_range:
/* Nothing changed, don't add outgoing edges. */
return SSA_PROP_NOT_INTERESTING;
varying:
set_value_range_to_varying (&vr_result);
scev_check:
/* If this is a loop PHI node SCEV may known more about its value-range.
scev_check can be reached from two paths, one is a fall through from above
"varying" label, the other is direct goto from code block which tries to
avoid infinite simulation. */
if ((l = loop_containing_stmt (phi))
&& l->header == gimple_bb (phi))
adjust_range_with_scev (&vr_result, l, phi, lhs);
infinite_check:
/* If we will end up with a (-INF, +INF) range, set it to
VARYING. Same if the previous max value was invalid for
the type and we end up with vr_result.min > vr_result.max. */
if ((vr_result.type == VR_RANGE || vr_result.type == VR_ANTI_RANGE)
&& !((vrp_val_is_max (vr_result.max) && vrp_val_is_min (vr_result.min))
|| compare_values (vr_result.min, vr_result.max) > 0))
goto update_range;
/* No match found. Set the LHS to VARYING. */
set_value_range_to_varying (lhs_vr);
return SSA_PROP_VARYING;
}
/* Simplify boolean operations if the source is known