re PR debug/70935 (ICE: verify_ssa failed (error: definition in block 9 does not…

re PR debug/70935 (ICE: verify_ssa failed (error: definition in block 9 does not dominate use in block 12) w/ -O3 -g)

gcc/

2016-05-06  Yuri Rumyantsev  <ysrumyan@gmail.com>

	PR debug/70935
	* tree-ssa-loop-unswitch.c (find_loop_guard): Reject guard edge with
	loop latch destination.

gcc/testsuite/

2016-05-06  Yuri Rumyantsev  <ysrumyan@gmail.com>

	PR debug/70935
	* gcc.dg/torture/pr70935.c: New test.

From-SVN: r235962

gcc/ChangeLog

+2016-05-06  Yuri Rumyantsev  <ysrumyan@gmail.com>
+
+	PR debug/70935
+	* tree-ssa-loop-unswitch.c (find_loop_guard): Reject guard edge with
+	loop latch destination.
+
 2016-05-06  Martin Liska  <mliska@suse.cz>
 
 	* tree-ssa-uninit.c: Apply manual changes

gcc/testsuite/ChangeLog

+2016-05-06  Yuri Rumyantsev  <ysrumyan@gmail.com>
+
+	PR debug/70935
+	* gcc.dg/torture/pr70935.c: New test.
+
 2016-05-06  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	PR target/58219

gcc/testsuite/gcc.dg/torture/pr70935.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -g" } */
+
+int d0, sj, v0, rp, zi;
+
+void
+zn(void)
+{
+  if (v0 != 0)
+    {
+      int *js, *r3;
+      int pm, gc;
+
+      for (gc = 0; gc < 1; ++gc)
+        {
+          sj = 1;
+          while (sj != 0)
+            ;
+        }
+      r3 = &pm;
+      *js = (long)&gc;
+ka:
+      for (d0 = 0; d0 < 2; ++d0)
+        {
+          d0 = zi;
+          if (zi)
+            for (pm = 2; pm != 0; --pm)
+              ;
+        }
+      while (*r3 != 0)
+        {
+          while (pm)
+            ;
+          ++r3;
+        }
+    }
+  rp = 0;
+  goto ka;
+}

gcc/tree-ssa-loop-unswitch.c

@@ -536,6 +536,12 @@ 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,