Fixed a strange construct, please review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@43278 91177308-0d34-0410-b5e6-96231b3b80d8

CodeGen/CodeGenTypes.cpp

@@ -254,7 +254,7 @@ void CodeGenTypes::DecodeArgumentTypes(const FunctionTypeProto &FTP,
 unsigned CodeGenTypes::getLLVMFieldNo(const FieldDecl *FD) {
   llvm::DenseMap<const FieldDecl *, unsigned>::iterator
     I = FieldInfo.find(FD);
-  if (I != FieldInfo.end()  && "Unable to find field info");
+  assert (I != FieldInfo.end()  && "Unable to find field info");
   return I->second;
 }