Don't pass -O0 to clang_cc1, it is the default.

llvm-svn: 189910
diff --git a/clang/test/CodeGenObjC/block-byref-variable-layout.m b/clang/test/CodeGenObjC/block-byref-variable-layout.m
index 9c8f674..a03617bc 100644
--- a/clang/test/CodeGenObjC/block-byref-variable-layout.m
+++ b/clang/test/CodeGenObjC/block-byref-variable-layout.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fblocks -fobjc-arc -fobjc-runtime-has-weak -triple x86_64-apple-darwin -O0 -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fblocks -fobjc-arc -fobjc-runtime-has-weak -triple x86_64-apple-darwin -emit-llvm %s -o - | FileCheck %s
 
 // rdar://12759433
 @class NSString;