[wasm] Use MachineOperatorBuilder::word() instead of kPointerSize to determine the word size.

src/compiler/int64-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/int64-lowering.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-properties.h"
@@ skipping 14 matching lines @@
       machine_(machine),
       common_(common),
       state_(graph, 4),
       stack_(zone),
       replacements_(zone->NewArray<Replacement>(graph->NodeCount())),
       signature_(signature) {
   memset(replacements_, 0, sizeof(Replacement) * graph->NodeCount());
 }
 
 void Int64Lowering::LowerGraph() {
-  if (4 != kPointerSize) {
+  if (!machine()->Is32()) {
     return;
   }
   stack_.push(graph()->end());
   state_.Set(graph()->end(), State::kOnStack);
 
   while (!stack_.empty()) {
     Node* top = stack_.top();
     if (state_.Get(top) == State::kInputsPushed) {
       stack_.pop();
       state_.Set(top, State::kVisited);
@@ skipping 389 matching lines @@
 }
 
 Node* Int64Lowering::GetReplacementHigh(Node* node) {
   Node* result = replacements_[node->id()].high;
   DCHECK(result);
   return result;
 }
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8