[turbofan] Implemented the optional Float32RoundDown operator.

src/compiler/mips/instruction-selector-mips.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/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 629 matching lines @@
 void InstructionSelector::VisitFloat32Sqrt(Node* node) {
   VisitRR(this, kMipsSqrtS, node);
 }
 
 
 void InstructionSelector::VisitFloat64Sqrt(Node* node) {
   VisitRR(this, kMipsSqrtD, node);
 }
 
 
+void InstructionSelector::VisitFloat32RoundDown(Node* node) { UNREACHABLE(); }
+
+
 void InstructionSelector::VisitFloat64RoundDown(Node* node) {
   VisitRR(this, kMipsFloat64RoundDown, node);
 }
 
 
 void InstructionSelector::VisitFloat64RoundUp(Node* node) {
   VisitRR(this, kMipsFloat64RoundUp, node);
 }
 
 
@@ skipping 522 matching lines @@
   }
   return flags | MachineOperatorBuilder::kFloat64Min |
          MachineOperatorBuilder::kFloat64Max |
          MachineOperatorBuilder::kFloat32Min |
          MachineOperatorBuilder::kFloat32Max;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8