[turbofan] First step towards correctified 64-bit addressing.

src/compiler/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 "src/compiler/simplified-lowering.h"
 
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 1129 matching lines @@
   const int element_size = ElementSizeOf(access.machine_type);
   if (element_size != 1) {
     index = graph()->NewNode(machine()->Int32Mul(), index,
                              jsgraph()->Int32Constant(element_size));
   }
   const int fixed_offset = access.header_size - access.tag();
   if (fixed_offset != 0) {
     index = graph()->NewNode(machine()->Int32Add(), index,
                              jsgraph()->Int32Constant(fixed_offset));
   }
-  // TODO(bmeurer): 64-Bit
-  // if (machine()->Is64()) {
-  //   index = graph()->NewNode(machine()->ChangeInt32ToInt64(), index);
-  // }
+  if (machine()->Is64()) {
+    // TODO(turbofan): This is probably only correct for typed arrays, and only
+    // if the typed arrays are at most 2GiB in size, which happens to match
+    // exactly our current situation.
+    index = graph()->NewNode(machine()->ChangeUint32ToUint64(), index);
+  }
   return index;
 }
 
 
 namespace {
 
 intptr_t AddressForOutOfBoundsLoad(MachineType type) {
   switch (RepresentationOf(type)) {
     case kRepFloat32: {
       static const float dummy = std::numeric_limits<float>::quiet_NaN();
@@ skipping 354 matching lines @@
 
 void SimplifiedLowering::DoStringLessThanOrEqual(Node* node) {
   node->set_op(machine()->IntLessThanOrEqual());
   node->ReplaceInput(0, StringComparison(node, true));
   node->ReplaceInput(1, jsgraph()->SmiConstant(EQUAL));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8