If we are compiling with -fno-builtin then don't do constant folding of
builtins.

This fixes PR11711.

llvm-svn: 147655
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 3e5a677..f462ee6 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -175,7 +175,8 @@
                                         unsigned BuiltinID, const CallExpr *E) {
   // See if we can constant fold this builtin.  If so, don't emit it at all.
   Expr::EvalResult Result;
-  if (E->EvaluateAsRValue(Result, CGM.getContext()) &&
+  if (!getContext().getLangOptions().NoBuiltin &&
+      E->EvaluateAsRValue(Result, CGM.getContext()) &&
       !Result.hasSideEffects()) {
     if (Result.Val.isInt())
       return RValue::get(llvm::ConstantInt::get(getLLVMContext(),