[compiler] Introduce code stubs for string relational comparisons.

test/cctest/compiler/test-simplified-lowering.cc

 // Copyright 2014 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.
 
 #include <limits>
 
 #include "src/ast/scopes.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/control-builders.h"
@@ skipping 1122 matching lines @@
 }
 
 
 TEST(LowerReferenceEqual_to_wordeq) {
   TestingGraph t(Type::Any(), Type::Any());
   IrOpcode::Value opcode =
       static_cast<IrOpcode::Value>(t.machine()->WordEqual()->opcode());
   t.CheckLoweringBinop(opcode, t.simplified()->ReferenceEqual(Type::Any()));
 }
 
-
-TEST(LowerStringOps_to_call_and_compare) {
-    // These tests need linkage for the calls.
-    TestingGraph t(Type::String(), Type::String());
-    IrOpcode::Value compare_lt =
-        static_cast<IrOpcode::Value>(t.machine()->IntLessThan()->opcode());
-    IrOpcode::Value compare_le = static_cast<IrOpcode::Value>(
-        t.machine()->IntLessThanOrEqual()->opcode());
-    t.CheckLoweringStringBinop(compare_lt, t.simplified()->StringLessThan());
-    t.CheckLoweringStringBinop(compare_le,
-                               t.simplified()->StringLessThanOrEqual());
-  }
-
-
-  void CheckChangeInsertion(IrOpcode::Value expected, MachineType from,
-                            MachineType to, Type* type = Type::Any()) {
+void CheckChangeInsertion(IrOpcode::Value expected, MachineType from,
+                          MachineType to, Type* type = Type::Any()) {
   TestingGraph t(Type::Any());
   Node* in = t.ExampleWithOutput(from);
   NodeProperties::SetType(in, type);
   Node* use = t.Use(in, to);
   t.Return(use);
   t.Lower();
   CHECK_EQ(expected, use->InputAt(0)->opcode());
   CHECK_EQ(in, use->InputAt(0)->InputAt(0));
 }
 
-
 TEST(InsertBasicChanges) {
   CheckChangeInsertion(IrOpcode::kChangeFloat64ToInt32, MachineType::Float64(),
                        MachineType::Int32(), Type::Signed32());
   CheckChangeInsertion(IrOpcode::kChangeFloat64ToUint32, MachineType::Float64(),
                        MachineType::Uint32(), Type::Unsigned32());
   CheckChangeInsertion(IrOpcode::kTruncateFloat64ToInt32,
                        MachineType::Float64(), MachineType::Uint32(),
                        Type::Integral32());
   CheckChangeInsertion(IrOpcode::kChangeTaggedToInt32, MachineType::AnyTagged(),
                        MachineType::Int32(), Type::Signed32());
@@ skipping 780 matching lines @@
     t.Return(use);
     t.Lower();
 
     CHECK_EQ(d.expected, PhiRepresentationOf(phi->op()));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8