[turbofan] Introduce new operators Float32SubPreserveNan and Float64SubPreserveNan for wasm.

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 736 matching lines @@
 
 void InstructionSelector::VisitFloat64Add(Node* node) {
   VisitRRR(this, kMipsAddD, node);
 }
 
 
 void InstructionSelector::VisitFloat32Sub(Node* node) {
   VisitRRR(this, kMipsSubS, node);
 }
 
+void InstructionSelector::VisitFloat32SubPreserveNan(Node* node) {
+  VisitRRR(this, kMipsSubS, node);
+}
 
 void InstructionSelector::VisitFloat64Sub(Node* node) {
   MipsOperandGenerator g(this);
   Float64BinopMatcher m(node);
   if (m.left().IsMinusZero() && m.right().IsFloat64RoundDown() &&
       CanCover(m.node(), m.right().node())) {
     if (m.right().InputAt(0)->opcode() == IrOpcode::kFloat64Sub &&
         CanCover(m.right().node(), m.right().InputAt(0))) {
       Float64BinopMatcher mright0(m.right().InputAt(0));
       if (mright0.left().IsMinusZero()) {
         Emit(kMipsFloat64RoundUp, g.DefineAsRegister(node),
              g.UseRegister(mright0.right().node()));
         return;
       }
     }
   }
   VisitRRR(this, kMipsSubD, node);
 }
 
+void InstructionSelector::VisitFloat64SubPreserveNan(Node* node) {
+  VisitRRR(this, kMipsSubD, node);
+}
 
 void InstructionSelector::VisitFloat32Mul(Node* node) {
   VisitRRR(this, kMipsMulS, node);
 }
 
 
 void InstructionSelector::VisitFloat64Mul(Node* node) {
   VisitRRR(this, kMipsMulD, node);
 }
 
@@ skipping 752 matching lines @@
          MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat32RoundDown |
          MachineOperatorBuilder::kFloat32RoundUp |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat32RoundTiesEven;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8