diff --git a/clang/lib/Analysis/PrintfFormatString.cpp b/clang/lib/Analysis/PrintfFormatString.cpp
index 46acc8a377bf1a9759c20ac34d170c58c7fb056c..c38aae34764c9af6f97cda28bace3909f03661d6 100644
--- a/clang/lib/Analysis/PrintfFormatString.cpp
+++ b/clang/lib/Analysis/PrintfFormatString.cpp
@@ -75,7 +75,7 @@ static OptionalAmount ParseAmount(const char *&Beg, const char *E) {
     char c = *I;
     if (c >= '0' && c <= '9') {
       hasDigits = true;
-      accumulator += (accumulator * 10) + (c - '0');
+      accumulator = (accumulator * 10) + (c - '0');
       continue;
     }