[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/arm64/instruction-selector-arm64.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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1389 matching lines @@
       break;
   }
   Emit(kArm64Mov32, g.DefineAsRegister(node), g.UseRegister(value));
 }
 
 
 void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
   VisitRR(this, kArm64Float64ToFloat32, node);
 }
 
+void InstructionSelector::VisitTruncateFloat64ToWord32(Node* node) {
+  VisitRR(this, kArchTruncateDoubleToI, node);
+}
 
-void InstructionSelector::VisitTruncateFloat64ToInt32(Node* node) {
-  switch (TruncationModeOf(node->op())) {
-    case TruncationMode::kJavaScript:
-      return VisitRR(this, kArchTruncateDoubleToI, node);
-    case TruncationMode::kRoundToZero:
-      return VisitRR(this, kArm64Float64ToInt32, node);
-  }
-  UNREACHABLE();
+void InstructionSelector::VisitRoundFloat64ToInt32(Node* node) {
+  VisitRR(this, kArm64Float64ToInt32, node);
 }
 
 
 void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
   Arm64OperandGenerator g(this);
   Node* value = node->InputAt(0);
   if (CanCover(node, value) && value->InputCount() >= 2) {
     Int64BinopMatcher m(value);
     if ((m.IsWord64Sar() && m.right().HasValue() &&
          (m.right().Value() == 32)) ||
@@ skipping 864 matching lines @@
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe |
          MachineOperatorBuilder::kWord32ReverseBits |
          MachineOperatorBuilder::kWord64ReverseBits;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8