Unify the handling of comparinsons against null and undefined.

src/arm/lithium-arm.cc

 // Copyright 2011 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 194 matching lines @@
 
 void LCmpIDAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if ");
   InputAt(0)->PrintTo(stream);
   stream->Add(" %s ", Token::String(op()));
   InputAt(1)->PrintTo(stream);
   stream->Add(" then B%d else B%d", true_block_id(), false_block_id());
 }
 
 
-void LIsNullAndBranch::PrintDataTo(StringStream* stream) {
+void LIsNilAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if ");
   InputAt(0)->PrintTo(stream);
-  stream->Add(is_strict() ? " === null" : " == null");
+  stream->Add(kind() == kStrictEquality ? " === " : " == ");
+  stream->Add(nil() == kNullValue ? "null" : "undefined");
   stream->Add(" then B%d else B%d", true_block_id(), false_block_id());
 }
 
 
 void LIsObjectAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if is_object(");
   InputAt(0)->PrintTo(stream);
   stream->Add(") then B%d else B%d", true_block_id(), false_block_id());
 }
 
@@ skipping 1208 matching lines @@
   return new LCmpObjectEqAndBranch(left, right);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareConstantEqAndBranch(
     HCompareConstantEqAndBranch* instr) {
   return new LCmpConstantEqAndBranch(UseRegisterAtStart(instr->value()));
 }
 
 
-LInstruction* LChunkBuilder::DoIsNullAndBranch(HIsNullAndBranch* instr) {
+LInstruction* LChunkBuilder::DoIsNilAndBranch(HIsNilAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
-  return new LIsNullAndBranch(UseRegisterAtStart(instr->value()));
+  return new LIsNilAndBranch(UseRegisterAtStart(instr->value()));
 }
 
 
 LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* temp = TempRegister();
   return new LIsObjectAndBranch(UseRegisterAtStart(instr->value()), temp);
 }
 
 
@@ skipping 722 matching lines @@
 
 LInstruction* LChunkBuilder::DoIn(HIn* instr) {
   LOperand* key = UseRegisterAtStart(instr->key());
   LOperand* object = UseRegisterAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, r0), instr);
 }
 
 
 } }  // namespace v8::internal