fix pr78384

	PR tree-optimization/78384
	* tree-ssa-loop-split.c (patch_loop_exit): Use correct edge.

testsuite/
	PR tree-optimization/78384
	* gcc.dg/pr78384.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@244811 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2017-01-23  Michael Matz  <[email protected]>
+
+	PR tree-optimization/78384
+	* tree-ssa-loop-split.c (patch_loop_exit): Use correct edge.
+
 2017-01-23  Richard Biener  <[email protected]>
 
 	PR tree-optimization/79186

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2017-01-23  Michael Matz  <[email protected]>
+
+	PR tree-optimization/78384
+	* gcc.dg/pr78384.c: New test.
+
 2017-01-23  Richard Biener  <[email protected]>
 
 	PR tree-optimization/79186

gcc/testsuite/gcc.dg/pr78384.c

@@ -0,0 +1,25 @@
+/* PR tree-optimization/78384
+   { dg-do compile }
+   { dg-options "-O3 -w -fsplit-loops" } */
+void
+a2 (int wv, int yg, int r9)
+{
+  while (wv < 1)
+    {
+      int vn = r9 % 0;
+
+      while (yg < 1)
+        {
+          int lz;
+
+          for (r9 = 0; r9 < 17; ++r9)
+            {
+            }
+
+ it:
+          lz = (yg++ >= 0) ? 2 : 0;
+          wv = vn < lz;
+        }
+    }
+  goto it;
+}

gcc/tree-ssa-loop-split.c

@@ -159,7 +159,7 @@ patch_loop_exit (struct loop *loop, gcond *guard, tree nextval, tree newbound,
 			     nextval, newbound);
   update_stmt (stmt);
 
-  edge stay = single_pred_edge (loop->latch);
+  edge stay = EDGE_SUCC (exit->src, EDGE_SUCC (exit->src, 0) == exit);
 
   exit->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
   stay->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);