diff --git a/ChangeLog b/ChangeLog
index bb84e32b5f..012fce4f69 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-02-15  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	* sysdeps/ieee754/dbl-64/mpa.c (__mul): Fix determination of
+	the lower precision input.
+
 2013-02-15  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #13550]
diff --git a/sysdeps/ieee754/dbl-64/mpa.c b/sysdeps/ieee754/dbl-64/mpa.c
index 542d81bdcc..25f52f65c6 100644
--- a/sysdeps/ieee754/dbl-64/mpa.c
+++ b/sysdeps/ieee754/dbl-64/mpa.c
@@ -612,6 +612,7 @@ __mul (const mp_no *x, const mp_no *y, mp_no *z, int p)
 {
   int i, j, k, ip, ip2;
   double u, zk;
+  const mp_no *a;
 
   /* Is z=0?  */
   if (__glibc_unlikely (X[0] * Y[0] == ZERO))
@@ -626,9 +627,11 @@ __mul (const mp_no *x, const mp_no *y, mp_no *z, int p)
     if (X[ip2] != ZERO || Y[ip2] != ZERO)
       break;
 
+  a = X[ip2] != ZERO ? y : x;
+
   /* ... and here, at least one of them is still zero.  */
   for (ip = ip2; ip > 0; ip--)
-    if (X[ip] * Y[ip] != ZERO)
+    if (a->d[ip] != ZERO)
       break;
 
   /* The product looks like this for p = 3 (as an example):