Refactor branch instructions to enable further optimizations.

runtime/vm/locations.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_LOCATIONS_H_
 #define VM_LOCATIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/bitfield.h"
@@ skipping 355 matching lines @@
 
   Location out() const {
     return output_location_;
   }
 
   Location* out_slot() {
     return &output_location_;
   }
 
   void set_out(Location loc) {
-    ASSERT(!always_calls() || loc.IsRegister());
+    ASSERT(!always_calls() || (loc.IsRegister() || loc.IsInvalid()));
     output_location_ = loc;
   }
 
   BitmapBuilder* stack_bitmap() const { return stack_bitmap_; }
 
   bool always_calls() const {
     return contains_call_ == kCall;
   }
 
   bool can_call() {
@@ skipping 18 matching lines @@
   BitmapBuilder* stack_bitmap_;
 
   const ContainsCall contains_call_;
   RegisterSet live_registers_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_LOCATIONS_H_