1 files changed, 18 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr20742.c b/gcc/testsuite/gcc.dg/tree-ssa/pr20742.c
new file mode 100644
index 000000000..21d6eb63c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr20742.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#define TEN(x) x x x x x x x x x x
+#define THOUSAND(x) TEN (TEN (TEN (x)))
+
+int
+foo (int x, int y)
+{
+  register int a = y + 57;
+  register int b = y + 31;
+
+  while (x-- > 0)
+    {
+      THOUSAND (a += b; b -= a;)
+    }
+  return a + b;
+}