[turbofan] Add support for relevant ES6 type conversion intrinsics.

test/unittests/compiler/js-typed-lowering-unittest.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 "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 446 matching lines @@
   Node* const effect = graph()->start();
   Node* const control = graph()->start();
   Reduction r = Reduce(graph()->NewNode(javascript()->ToObject(), input,
                                         context, frame_state, effect, control));
   ASSERT_TRUE(r.Changed());
   EXPECT_EQ(input, r.replacement());
 }
 
 
 // -----------------------------------------------------------------------------
+// JSToString
+
+
+TEST_F(JSTypedLoweringTest, JSToStringWithBoolean) {
+  Node* const input = Parameter(Type::Boolean(), 0);
+  Node* const context = Parameter(Type::Any(), 1);
+  Node* const frame_state = EmptyFrameState();
+  Node* const effect = graph()->start();
+  Node* const control = graph()->start();
+  Reduction r = Reduce(graph()->NewNode(javascript()->ToString(), input,
+                                        context, frame_state, effect, control));
+  ASSERT_TRUE(r.Changed());
+  EXPECT_THAT(
+      r.replacement(),
+      IsSelect(kMachAnyTagged, input, IsHeapConstant(factory()->true_string()),
+               IsHeapConstant(factory()->false_string())));
+}
+
+
+// -----------------------------------------------------------------------------
 // JSStrictEqual
 
 
 TEST_F(JSTypedLoweringTest, JSStrictEqualWithTheHole) {
   Node* const the_hole = HeapConstant(factory()->the_hole_value());
   Node* const context = UndefinedConstant();
   TRACED_FOREACH(Type*, type, kJSTypes) {
     Node* const lhs = Parameter(type);
     Reduction r =
         Reduce(graph()->NewNode(javascript()->StrictEqual(), lhs, the_hole,
@@ skipping 667 matching lines @@
   EXPECT_THAT(r.replacement(),
               IsFinishRegion(IsAllocate(IsNumberConstant(Context::SizeFor(
                                             Context::MIN_CONTEXT_SLOTS)),
                                         IsBeginRegion(effect), control),
                              _));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8