Optimize numeric comparison with known successors.

src/x64/lithium-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1603 matching lines @@
   LOperand* context = UseFixed(instr->context(), rsi);
   LOperand* left = UseFixed(instr->left(), rdx);
   LOperand* right = UseFixed(instr->right(), rax);
   LCmpT* result = new(zone()) LCmpT(context, left, right);
   return MarkAsCall(DefineFixed(result, rax), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareNumericAndBranch(
     HCompareNumericAndBranch* instr) {
+  LInstruction* goto_instr = CheckElideControlInstruction(instr);
+  if (goto_instr != NULL) return goto_instr;
   Representation r = instr->representation();
   if (r.IsSmiOrInteger32()) {
     ASSERT(instr->left()->representation().Equals(r));
     ASSERT(instr->right()->representation().Equals(r));
     LOperand* left = UseRegisterOrConstantAtStart(instr->left());
     LOperand* right = UseOrConstantAtStart(instr->right());
     return new(zone()) LCompareNumericAndBranch(left, right);
   } else {
     ASSERT(r.IsDouble());
     ASSERT(instr->left()->representation().IsDouble());
@@ skipping 973 matching lines @@
   LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64