[turbofan] Improve typed lowering for JSToBoolean.

src/compiler/access-builder.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/compiler/access-builder.h"
 #include "src/types-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 41 matching lines @@
 
 
 // static
 FieldAccess AccessBuilder::ForMapInstanceType() {
   return {kTaggedBase, Map::kInstanceTypeOffset, Handle<Name>(),
           Type::UntaggedInt8(), kMachUint8};
 }
 
 
 // static
+FieldAccess AccessBuilder::ForStringLength() {
+  return {kTaggedBase, String::kLengthOffset, Handle<Name>(),
+          Type::SignedSmall(), kMachAnyTagged};
+}
+
+
+// static
 FieldAccess AccessBuilder::ForValue() {
   return {kTaggedBase, JSValue::kValueOffset, Handle<Name>(), Type::Any(),
           kMachAnyTagged};
 }
 
 
 // static
 ElementAccess AccessBuilder::ForFixedArrayElement() {
   return {kNoBoundsCheck, kTaggedBase, FixedArray::kHeaderSize, Type::Any(),
           kMachAnyTagged};
@@ skipping 32 matching lines @@
       return {kTypedArrayBoundsCheck, taggedness, header_size, Type::Number(),
               kRepFloat64};
   }
   UNREACHABLE();
   return {kTypedArrayBoundsCheck, kUntaggedBase, 0, Type::None(), kMachNone};
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8