Improve overflow detection in StringRef::getAsUnsignedInteger().

llvm-svn: 165038
2012-10-02 20:01:48 +00:00 · 2012-10-02 20:01:48 +00:00 · 35c79da3f8
parent 8a5bc6edca
commit 35c79da3f8
1 changed files with 2 additions and 2 deletions
--- a/llvm/lib/Support/StringRef.cpp
+++ b/llvm/lib/Support/StringRef.cpp
@ -350,8 +350,8 @@ bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
    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);