[Bug debug/70935] [6/7 Regression] ICE: verify_ssa failed (error: definition in block 9 does not dominate use in block 12) w/ -O3 -g

["ysrumyan at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70935

--- Comment #3 from Yuri Rumyantsev <ysrumyan at gmail dot com> ---
Jacub,

Here is a simple fix - do not take into consideration edges destination of
which is loop latch block, i.e. loop is endless:
diff --git a/gcc/tree-ssa-loop-unswitch.c b/gcc/tree-ssa-loop-unswitch.c
index dd6fd01..7de5fba 100644
--- a/gcc/tree-ssa-loop-unswitch.c
+++ b/gcc/tree-ssa-loop-unswitch.c
@@ -532,6 +532,12 @@ find_loop_guard (struct loop *loop)
                 guard_edge->src->index, guard_edge->dest->index);
       return NULL;
     }
+  if (guard_edge->dest == loop->latch)
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf(dump_file,"Guard edge destination is loop latch!\n");
+      return NULL;
+    }

   if (dump_file && (dump_flags & TDF_DETAILS))
     fprintf (dump_file,

Is it OK for you?