1 files changed, 29 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/torture/pr23821.c b/gcc/testsuite/gcc.dg/torture/pr23821.c
new file mode 100644
index 000000000..7632d8425
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr23821.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+/* At -O1 DOM threads a jump in a non-optimal way which leads to
+   the bogus propagation.  */
+/* { dg-skip-if "" { *-*-* } { "-O1" } { "" } } */
+/* { dg-options "-fdump-tree-ivcanon-details" } */
+
+int a[199];
+
+extern void abort (void);
+
+int
+main ()
+{
+  int i, x;
+  for (i = 0; i < 199; i++)
+    {
+      x = a[i];
+      if (x != i)
+	abort ();
+    }
+  return 0;
+}
+
+/* Verify that we do not propagate the equivalence x == i into the
+   induction variable increment.  */
+
+/* { dg-final { scan-tree-dump "Added canonical iv" "ivcanon" } } */
+/* { dg-final { cleanup-tree-dump "ivcanon" } } */