1 files changed, 54 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr21417.c b/gcc/testsuite/gcc.dg/tree-ssa/pr21417.c
new file mode 100644
index 000000000..4a2c82143
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr21417.c
@@ -0,0 +1,54 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-dom2-details" } */
+
+struct tree_common 
+{ 
+  int code; 
+}; 
+union tree_node 
+{ 
+  struct tree_common common; 
+}; 
+typedef union tree_node *tree; 
+ 
+extern tree test (tree, int, int); 
+extern tree foo (void); 
+extern void abort (void) __attribute__ ((__noreturn__)); 
+ 
+tree 
+test (tree expr, int t, int D17630) 
+{ 
+  int __i; 
+ 
+L0: 
+  if (expr->common.code != 142) goto L23; else goto L2; 
+ 
+L2: 
+  __i = 0; 
+  goto L10; 
+ 
+L10: 
+  __i = __i + 1; 
+  if (D17630 != __i) goto L8; else goto L19; 
+ 
+L8: 
+  if (t) goto L15; else goto L10; 
+ 
+L15: 
+  expr = foo (); 
+  if (expr->common.code != 142) goto L23; else goto L0; 
+ 
+L19: 
+  abort (); 
+ 
+L23: 
+  return expr; 
+} 
+
+
+/* We should thread the backedge to the top of the loop; ie we only
+   execute the if (expr->common.code != 142) test once per loop
+   iteration.  */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "dom2" } } */
+/* { dg-final { cleanup-tree-dump "dom2" } } */
+