X87: [turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/x87/instruction-selector-x87.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/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
@@ skipping 828 matching lines @@
 }
 
 void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
   X87OperandGenerator g(this);
   Emit(kX87Float64ToFloat32, g.DefineAsFixed(node, stX_0),
        g.Use(node->InputAt(0)));
 }
 
 void InstructionSelector::VisitTruncateFloat64ToWord32(Node* node) {
   X87OperandGenerator g(this);
+  Emit(kArchTruncateDoubleToI, g.DefineAsRegister(node),
+       g.Use(node->InputAt(0)));
+}
 
-  switch (TruncationModeOf(node->op())) {
-    case TruncationMode::kJavaScript:
-      Emit(kArchTruncateDoubleToI, g.DefineAsRegister(node),
-           g.Use(node->InputAt(0)));
-      return;
-    case TruncationMode::kRoundToZero:
-      Emit(kX87Float64ToInt32, g.DefineAsRegister(node),
-           g.Use(node->InputAt(0)));
-      return;
-  }
-  UNREACHABLE();
+void InstructionSelector::VisitRoundFloat64ToInt32(Node* node) {
+  X87OperandGenerator g(this);
+  Emit(kX87Float64ToInt32, g.DefineAsRegister(node), g.Use(node->InputAt(0)));
 }
 
 
 void InstructionSelector::VisitBitcastFloat32ToInt32(Node* node) {
   X87OperandGenerator g(this);
   Emit(kX87PushFloat32, g.NoOutput(), g.Use(node->InputAt(0)));
   Emit(kX87BitcastFI, g.DefineAsRegister(node), 0, nullptr);
 }
 
 
@@ skipping 747 matching lines @@
            MachineOperatorBuilder::kFloat32RoundTruncate |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kFloat32RoundTiesEven |
            MachineOperatorBuilder::kFloat64RoundTiesEven;
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8