[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/x64/instruction-selector-x64.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 <algorithm>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
@@ skipping 1123 matching lines @@
   }
 }
 
 }  // namespace
 
 
 void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
   VisitRO(this, node, kSSEFloat64ToFloat32);
 }
 
-
-void InstructionSelector::VisitTruncateFloat64ToInt32(Node* node) {
-  switch (TruncationModeOf(node->op())) {
-    case TruncationMode::kJavaScript:
-      return VisitRR(this, node, kArchTruncateDoubleToI);
-    case TruncationMode::kRoundToZero:
-      return VisitRO(this, node, kSSEFloat64ToInt32);
-  }
-  UNREACHABLE();
+void InstructionSelector::VisitTruncateFloat64ToWord32(Node* node) {
+  VisitRR(this, node, kArchTruncateDoubleToI);
 }
 
 
 void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
   X64OperandGenerator g(this);
   Node* value = node->InputAt(0);
   if (CanCover(node, value)) {
     switch (value->opcode()) {
       case IrOpcode::kWord64Sar:
       case IrOpcode::kWord64Shr: {
         Int64BinopMatcher m(value);
         if (m.right().Is(32)) {
           Emit(kX64Shr, g.DefineSameAsFirst(node),
                g.UseRegister(m.left().node()), g.TempImmediate(32));
           return;
         }
         break;
       }
       default:
         break;
     }
   }
   Emit(kX64Movl, g.DefineAsRegister(node), g.Use(value));
 }
 
+void InstructionSelector::VisitRoundFloat64ToInt32(Node* node) {
+  VisitRO(this, node, kSSEFloat64ToInt32);
+}
 
 void InstructionSelector::VisitRoundInt32ToFloat32(Node* node) {
   X64OperandGenerator g(this);
   Emit(kSSEInt32ToFloat32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitRoundInt64ToFloat32(Node* node) {
   X64OperandGenerator g(this);
   Emit(kSSEInt64ToFloat32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
@@ skipping 868 matching lines @@
              MachineOperatorBuilder::kFloat64RoundTruncate |
              MachineOperatorBuilder::kFloat32RoundTiesEven |
              MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8