[compiler] Introduce StringEqualStub and StringNotEqualStub.

src/crankshaft/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/crankshaft/x64/lithium-codegen-x64.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2300 matching lines @@
            Immediate(1 << Map::kIsUndetectable));
   EmitBranch(instr, not_zero);
 }
 
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   DCHECK(ToRegister(instr->context()).is(rsi));
   DCHECK(ToRegister(instr->left()).is(rdx));
   DCHECK(ToRegister(instr->right()).is(rax));
 
-  Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
-  CallCode(code, RelocInfo::CODE_TARGET, instr);
-  __ testp(rax, rax);
+  if (Token::IsOrderedRelationalCompareOp(instr->op())) {
+    Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
+    CallCode(code, RelocInfo::CODE_TARGET, instr);
+    __ testp(rax, rax);
+  } else {
+    Handle<Code> code = CodeFactory::StringEqual(isolate()).code();
+    CallCode(code, RelocInfo::CODE_TARGET, instr);
+    __ CompareRoot(rax, Heap::kTrueValueRootIndex);
+  }
 
   EmitBranch(instr, TokenToCondition(instr->op(), false));
 }
 
 
 static InstanceType TestType(HHasInstanceTypeAndBranch* instr) {
   InstanceType from = instr->from();
   InstanceType to = instr->to();
   if (from == FIRST_TYPE) return to;
   DCHECK(from == to || to == LAST_TYPE);
@@ skipping 3181 matching lines @@
   __ movp(Operand(rbp, StandardFrameConstants::kContextOffset), context);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64