Introduce %_IsMinusZero.

src/hydrogen.cc

 // Copyright 2013 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 8760 matching lines @@
 void HOptimizedGraphBuilder::GenerateIsFunction(CallRuntime* call) {
   ASSERT(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HHasInstanceTypeAndBranch* result =
       New<HHasInstanceTypeAndBranch>(value, JS_FUNCTION_TYPE);
   return ast_context()->ReturnControl(result, call->id());
 }
 
 
+void HOptimizedGraphBuilder::GenerateIsMinusZero(CallRuntime* call) {
+  ASSERT(call->arguments()->length() == 1);
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  HValue* value = Pop();
+  HCompareMinusZeroAndBranch* result = New<HCompareMinusZeroAndBranch>(value);
+  return ast_context()->ReturnControl(result, call->id());
+}
+
+
 void HOptimizedGraphBuilder::GenerateHasCachedArrayIndex(CallRuntime* call) {
   ASSERT(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HHasCachedArrayIndexAndBranch* result =
       New<HHasCachedArrayIndexAndBranch>(value);
   return ast_context()->ReturnControl(result, call->id());
 }
 
 
@@ skipping 1063 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal