diff --git a/ChangeLog b/ChangeLog
index f0fe7f37a5..bdc3851f2d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Apr 22 10:25:21 2013  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* util.c (ruby_hdtoa): revert r29729.
+	  If you want ruby to behave as before on x86, specify to use SSE like
+	  -msse2 -mfpmath=sse for gcc.
+
 Sun Apr 21 23:19:00 2013  Charlie Somerville  <charlie@charliesomerville.com>
 
 	* configure.in: Revert using sigsetjmp by default due to performance
diff --git a/util.c b/util.c
index 733045daa4..fb72931ed5 100644
--- a/util.c
+++ b/util.c
@@ -3878,13 +3878,10 @@ ruby_hdtoa(double d, const char *xdigs, int ndigits, int *decpt, int *sign,
 	/* Round to the desired number of digits. */
 	if (SIGFIGS > ndigits && ndigits > 0) {
 		float redux = 1.0f;
-		volatile double d;
 		int offset = 4 * ndigits + DBL_MAX_EXP - 4 - DBL_MANT_DIG;
 		dexp_set(u, offset);
-		d = u.d;
-		d += redux;
-		d -= redux;
-		u.d = d;
+		u.d += redux;
+		u.d -= redux;
 		*decpt += dexp_get(u) - offset;
 	}