[turbofan] Implemented the optional Float32RoundDown 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 1455 matching lines @@
 void InstructionSelector::VisitFloat32Sqrt(Node* node) {
   VisitRR(this, kArm64Float32Sqrt, node);
 }
 
 
 void InstructionSelector::VisitFloat64Sqrt(Node* node) {
   VisitRR(this, kArm64Float64Sqrt, node);
 }
 
 
+void InstructionSelector::VisitFloat32RoundDown(Node* node) {
+  VisitRR(this, kArm64Float32RoundDown, node);
+}
+
+
 void InstructionSelector::VisitFloat64RoundDown(Node* node) {
   VisitRR(this, kArm64Float64RoundDown, node);
 }
 
 
 void InstructionSelector::VisitFloat64RoundUp(Node* node) {
   VisitRR(this, kArm64Float64RoundUp, node);
 }
 
 
@@ skipping 571 matching lines @@
   Emit(kArm64Float64InsertHighWord32, g.DefineAsRegister(node),
        g.UseRegister(left), g.UseRegister(right));
 }
 
 
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat32Min |
+         MachineOperatorBuilder::kFloat32RoundDown |
          MachineOperatorBuilder::kFloat64Max |
          MachineOperatorBuilder::kFloat64Min |
          MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat64RoundUp |
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8