diff --git a/double-conversion/fixed-dtoa.cc b/double-conversion/fixed-dtoa.cc
index 78378c5..e06617b 100644
--- a/double-conversion/fixed-dtoa.cc
+++ b/double-conversion/fixed-dtoa.cc
@@ -259,7 +259,7 @@
       fractionals -= static_cast<uint64_t>(digit) << point;
     }
     // If the first bit after the point is set we have to round up.
-    if (((fractionals >> (point - 1)) & 1) == 1) {
+    if ((fractionals != 0) && ((fractionals >> (point - 1)) & 1) == 1) {
       RoundUp(buffer, length, decimal_point);
     }
   } else {  // We need 128 bits.