Fixing a corner-case bug in strchr and strrchr lib call optimizations where

the input character is not converted to char before comparing with zero.

The patch was discussed in this thread:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130812/184069.html

llvm-svn: 188489

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 094c20154af..93720be683e 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -477,7 +477,7 @@ struct StrChrOpt : public LibCallOptimization {
 
     // Compute the offset, make sure to handle the case when we're searching for
     // zero (a weird way to spell strlen).
-    size_t I = CharC->getSExtValue() == 0 ?
+    size_t I = (255 & CharC->getSExtValue()) == 0 ?
         Str.size() : Str.find(CharC->getSExtValue());
     if (I == StringRef::npos) // Didn't find the char.  strchr returns null.
       return Constant::getNullValue(CI->getType());
@@ -513,7 +513,7 @@ struct StrRChrOpt : public LibCallOptimization {
     }
 
     // Compute the offset.
-    size_t I = CharC->getSExtValue() == 0 ?
+    size_t I = (255 & CharC->getSExtValue()) == 0 ?
         Str.size() : Str.rfind(CharC->getSExtValue());
     if (I == StringRef::npos) // Didn't find the char. Return null.
       return Constant::getNullValue(CI->getType());