Index: dtoa.cc
===================================================================
--- dtoa.cc	(revision 161424)
+++ dtoa.cc	(working copy)
@@ -3569,7 +3569,7 @@
 	int denorm;
 	ULong x;
 #endif
-	Bigint *b, *b1, *delta, *mlo, *mhi, *S;
+	Bigint *b, *b1, *delta, *mlo = NULL, *mhi, *S;
 	U d2, eps, u;
 	double ds;
 	char *s, *s0;