Fuse comparisons that are used by branches together.

runtime/vm/flow_graph_compiler_x64.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_FLOW_GRAPH_COMPILER_X64_H_
 #define VM_FLOW_GRAPH_COMPILER_X64_H_
 
 #ifndef VM_FLOW_GRAPH_COMPILER_H_
 #error Include flow_graph_compiler.h instead of flow_graph_compiler_x64.h.
 #endif
@@ skipping 149 matching lines @@
                       Register reg1 = kNoRegister,
                       Register reg2 = kNoRegister,
                       Register reg3 = kNoRegister);
 
   void FinalizeExceptionHandlers(const Code& code);
   void FinalizePcDescriptors(const Code& code);
   void FinalizeStackmaps(const Code& code);
   void FinalizeVarDescriptors(const Code& code);
   void FinalizeComments(const Code& code);
 
+  const Bool& true_value() const { return true_value_; }
+  const Bool& false_value() const { return false_value_; }
+
   static const int kLocalsOffsetFromFP = (-1 * kWordSize);
 
  private:
   friend class DeoptimizationStub;
 
   void GenerateDeferredCode();
 
   virtual void EmitInstructionPrologue(Instruction* instr);
 
   // Emit code to load a Value into register 'dst'.
@@ skipping 79 matching lines @@
   // for convenience.  This is not the block's index in the block order,
   // which is reverse postorder.
   BlockEntryInstr* current_block_;
   ExceptionHandlerList* exception_handlers_list_;
   DescriptorList* pc_descriptors_list_;
   StackmapBuilder* stackmap_builder_;
   GrowableArray<BlockInfo*> block_info_;
   GrowableArray<DeoptimizationStub*> deopt_stubs_;
   const bool is_optimizing_;
 
+  const Bool& true_value_;
+  const Bool& false_value_;
+
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 
 class DeoptimizationStub : public ZoneAllocated {
  public:
   DeoptimizationStub(intptr_t deopt_id,
                      intptr_t deopt_token_index,
                      intptr_t try_index,
                      DeoptReasonId reason)
@@ skipping 17 matching lines @@
   const DeoptReasonId reason_;
   GrowableArray<Register> registers_;
   Label entry_label_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptimizationStub);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_X64_H_