fix SimplifyLibCalls/IsDigit.ll

llvm-svn: 36047
diff --git a/llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp b/llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp
index b7b5bee..5900a02 100644
--- a/llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp
@@ -1571,7 +1571,7 @@
                               ConstantInt::get(V->getType(), 128), 
                               V->getName()+".isascii", CI);
     if (Cmp->getType() != CI->getType())
-      Cmp = new BitCastInst(Cmp, CI->getType(), Cmp->getName(), CI);
+      Cmp = new ZExtInst(Cmp, CI->getType(), Cmp->getName(), CI);
     return ReplaceCallWith(CI, Cmp);
   }
 } isasciiOptimizer;