commit 35c79da3f890c28dabedbe1be3880972f706e105
author Nick Kledzik <kledzik@apple.com> Tue Oct 02 20:01:48 2012 +0000
committer Nick Kledzik <kledzik@apple.com> Tue Oct 02 20:01:48 2012 +0000
tree 8f6a81d19b0ede66d710665e3c5811b2d08a175d
parent 8a5bc6edca4f7ff8553957bedfab55e7f0b7041e

Improve overflow detection in StringRef::getAsUnsignedInteger().

llvm-svn: 165038

llvm/lib/Support/StringRef.cpp

diff --git a/llvm/lib/Support/StringRef.cpp b/llvm/lib/Support/StringRef.cpp
index 8aab4b2..f8e9208 100644
--- a/llvm/lib/Support/StringRef.cpp
+++ b/llvm/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);