http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57235
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2013-05-10
Component|tree-optimization |middle-end
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Target Milestone|--- |4.9.0
Summary|ICE verify_ssa failied |[4.9 Regression] ICE
| |verify_ssa failied
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. This is because GIMPLE_RESX does not have virtual operands and thus
there doesn't need to be a PHI node to merge the virtual operand chain into
the successor we move the clobber to.
GIMPLE_RETURNs now always have a virtual use to ease updating SSA form.
Possible fix that disables the transform in these cases:
Index: gcc/tree-eh.c
===================================================================
--- gcc/tree-eh.c (revision 198768)
+++ gcc/tree-eh.c (working copy)
@@ -3360,6 +3360,11 @@ sink_clobbers (basic_block bb)
}
}
+ /* ??? If we have multiple predecessors but no virtual PHI we cannot
+ easily update virtual SSA form. */
+ if (!vphi && !single_pred_p (succbb))
+ return 0;
+
dgsi = gsi_after_labels (succbb);
gsi = gsi_last_bb (bb);
for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
thus not sink the clobber.
Another possibility is to remove such clobbers instead (if the block is
reachable from elsewhere we may increase the objects lifetime by the
sinking).
