diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 83edb9b1965..b4febea6753 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-11-28  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	PR rtl-optimization/55052
+	* simplify-rtx.c (simplify_subreg): Restore SCALAR_INT_MODE_P check.
+
 2012-11-28  David Edelsohn  <dje.gcc@gmail.com>
 
 	* target.def (use_blocks_for_decl_p): New hook.
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 46d9e8a1ede..f26f0083cf6 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -5875,7 +5875,7 @@ simplify_subreg (enum machine_mode outermode, rtx op,
 
   /* A SUBREG resulting from a zero extension may fold to zero if
      it extracts higher bits that the ZERO_EXTEND's source bits.  */
-  if (GET_CODE (op) == ZERO_EXTEND)
+  if (GET_CODE (op) == ZERO_EXTEND && SCALAR_INT_MODE_P (innermode))
     {
       unsigned int bitpos = subreg_lsb_1 (outermode, innermode, byte);
       if (bitpos >= GET_MODE_PRECISION (GET_MODE (XEXP (op, 0))))