Improve overflow detection in StringRef::getAsUnsignedInteger().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165038 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp
index 8aab4b2..f8e9208 100644
--- a/lib/Support/StringRef.cpp
+++ b/lib/Support/StringRef.cpp
@@ -350,8 +350,8 @@
unsigned long long PrevResult = Result;
Result = Result*Radix+CharVal;
- // Check for overflow.
- if (Result < PrevResult)
+ // Check for overflow by shifting back and seeing if bits were lost.
+ if (Result/Radix < PrevResult)
return true;
Str = Str.substr(1);