[turbofan] Properly emit bounds checks for typed array element loads.

src/compiler/js-typed-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 "src/compiler/access-builder.h"
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-aux-data-inl.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 516 matching lines @@
 }
 
 
 Reduction JSTypedLowering::ReduceJSLoadProperty(Node* node) {
   Node* key = NodeProperties::GetValueInput(node, 1);
   Node* base = NodeProperties::GetValueInput(node, 0);
   Type* key_type = NodeProperties::GetBounds(key).upper;
   Type* base_type = NodeProperties::GetBounds(base).upper;
   // TODO(mstarzinger): This lowering is not correct if:
   //   a) The typed array or it's buffer is neutered.
-  //   b) The index is out of bounds.
   if (base_type->IsConstant() && key_type->Is(Type::Integral32()) &&
       base_type->AsConstant()->Value()->IsJSTypedArray()) {
     // JSLoadProperty(typed-array, int32)
     Handle<JSTypedArray> array =
         Handle<JSTypedArray>::cast(base_type->AsConstant()->Value());
     if (IsExternalArrayElementsKind(array->map()->elements_kind())) {
       ExternalArrayType type = array->type();
       uint32_t length;
       CHECK(array->length()->ToUint32(&length));
       Node* elements = graph()->NewNode(
@@ skipping 143 matching lines @@
       return JSBuiltinReducer(jsgraph()).Reduce(node);
     default:
       break;
   }
   return NoChange();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8