diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a887db195e1..49d2b33fdb0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2008-12-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* cse.c (equiv_constant): Fix pasto.
+
 2008-12-04  Nick Clifton  <nickc@redhat.com>
 
 	* config/stormy16/stormy16.md: Remove extraneous spaces and
diff --git a/gcc/cse.c b/gcc/cse.c
index e6ff6308c2a..f52f0a9c93d 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -3651,7 +3651,7 @@ equiv_constant (rtx x)
 
       if (REG_P (SUBREG_REG (x))
 	  && (new_rtx = equiv_constant (SUBREG_REG (x))) != 0)
-        return simplify_subreg (GET_MODE (x), SUBREG_REG (x),
+        return simplify_subreg (GET_MODE (x), new_rtx,
 				GET_MODE (SUBREG_REG (x)), SUBREG_BYTE (x));
 
       return 0;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 37ba7905cc6..e54d5eabefe 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2008-12-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.dg/union-4.c: New test.
+
 2008-12-03  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* g++.old-deja/g++.eh/badalloc1.C: Add the missing "}".
diff --git a/gcc/testsuite/gcc.dg/union-4.c b/gcc/testsuite/gcc.dg/union-4.c
new file mode 100644
index 00000000000..df9f36da09b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/union-4.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-rtl-cse1" } */
+
+extern void abort(void);
+
+typedef unsigned int uint32;
+typedef unsigned long long uint64;
+
+typedef union {
+  uint32 i32;
+  uint64 i64;
+} u64;
+
+void foo(void)
+{
+  u64 data;
+  data.i64 = 1;
+  if (data.i32 != 1)
+    abort ();
+}
+
+/* { dg-final { scan-rtl-dump-not "abort" "cse1" { target i?86-*-* } } } */
+/* { dg-final { cleanup-rtl-dump "cse1" } } */