Disable Subzero IR generation for performance testing.

src/IceGlobalContext.h

 //===- subzero/src/IceGlobalContext.h - Global context defs -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares aspects of the compilation that persist across
@@ skipping 122 matching lines @@
                                               unsigned CallingConv,
                                               unsigned Linkage, bool IsProto);
 
   // Returns a new global variable declaration, allocated in an
   // internal memory pool.  Ownership of the function is maintained by
   // this class instance.
   VariableDeclaration *newVariableDeclaration();
 
   const ClFlags &getFlags() const { return Flags; }
 
+  bool isIRGenerationDisabled() const {
+    return ALLOW_DISABLE_IR_GEN ? getFlags().DisableIRGeneration : false;
+  }
+
   // Allocate data of type T using the global allocator.
   template <typename T> T *allocate() { return Allocator.Allocate<T>(); }
 
   const Intrinsics &getIntrinsicsInfo() const { return IntrinsicsInfo; }
 
   // TODO(wala,stichnot): Make the RNG play nicely with multithreaded
   // translation.
   RandomNumberGenerator &getRNG() { return RNG; }
 
   // Reset stats at the beginning of a function.
@@ skipping 82 matching lines @@
 
 private:
   TimerIdT ID;
   GlobalContext *const Ctx;
   const bool Active;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEGLOBALCONTEXT_H