http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53168
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |steven at gcc dot gnu.org
--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-02
15:00:54 UTC ---
It's what I always wondered about ... we phi-translate again during
do_regular_insertion but we fail to "clean" the result in any way. So
we end with a translation result that is "invalid", thus one without
a leader and one which we cannot re-create. That is, valid_in_sets returns
false for it.
Index: gcc/tree-ssa-pre.c
===================================================================
--- gcc/tree-ssa-pre.c (revision 187042)
+++ gcc/tree-ssa-pre.c (working copy)
@@ -3617,6 +3619,11 @@ do_regular_insertion (basic_block block,
vprime, NULL);
if (edoubleprime == NULL)
{
+ if (!valid_in_sets (AVAIL_OUT (bprime), NULL, eprime,
bprime))
+ {
+ cant_insert = true;
+ break;
+ }
avail[bprime->index] = eprime;
all_same = false;
}
Steven - do you by chance remember why "re-translating" during insertion
is ok? Or is a phi-translation result that cannot be inserted in its
form at the end of the BB bogus (always? or only during insertion?).
