diff --git a/llvm/include/llvm/ADT/StringExtras.h b/llvm/include/llvm/ADT/StringExtras.h
index 56d5f3d05857..990a3054a9d2 100644
--- a/llvm/include/llvm/ADT/StringExtras.h
+++ b/llvm/include/llvm/ADT/StringExtras.h
@@ -245,7 +245,7 @@ inline std::string utostr(uint64_t X, bool isNeg = false) {
 
 inline std::string itostr(int64_t X) {
   if (X < 0)
-    return utostr(static_cast<uint64_t>(-X), true);
+    return utostr(-static_cast<uint64_t>(X), true);
   else
     return utostr(static_cast<uint64_t>(X));
 }