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

src/compiler/ppc/instruction-selector-ppc.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"
 #include "src/ppc/frames-ppc.h"
 
@@ skipping 1208 matching lines @@
   PPCOperandGenerator g(this);
   Float32BinopMatcher m(node);
   if (m.left().IsMinusZero()) {
     Emit(kPPC_NegDouble | MiscField::encode(1), g.DefineAsRegister(node),
          g.UseRegister(m.right().node()));
     return;
   }
   VisitRRR(this, kPPC_SubDouble | MiscField::encode(1), node);
 }
 
+void InstructionSelector::VisitFloat32SubPreserveNan(Node* node) {
+  PPCOperandGenerator g(this);
+  VisitRRR(this, kPPC_SubDouble | MiscField::encode(1), node);
+}
 
 void InstructionSelector::VisitFloat64Sub(Node* node) {
   // TODO(mbrandy): detect multiply-subtract
   PPCOperandGenerator g(this);
   Float64BinopMatcher m(node);
   if (m.left().IsMinusZero()) {
     if (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()) {
           // -floor(-x) = ceil(x)
           Emit(kPPC_CeilDouble, g.DefineAsRegister(node),
                g.UseRegister(mright0.right().node()));
           return;
         }
       }
     }
     Emit(kPPC_NegDouble, g.DefineAsRegister(node),
          g.UseRegister(m.right().node()));
     return;
   }
   VisitRRR(this, kPPC_SubDouble, node);
 }
 
+void InstructionSelector::VisitFloat64SubPreserveNan(Node* node) {
+  VisitRRR(this, kPPC_SubDouble, node);
+}
 
 void InstructionSelector::VisitFloat32Mul(Node* node) {
   VisitRRR(this, kPPC_MulDouble | MiscField::encode(1), node);
 }
 
 
 void InstructionSelector::VisitFloat64Mul(Node* node) {
   // TODO(mbrandy): detect negate
   VisitRRR(this, kPPC_MulDouble, node);
 }
@@ skipping 715 matching lines @@
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32Popcnt |
          MachineOperatorBuilder::kWord64Popcnt;
   // We omit kWord32ShiftIsSafe as s[rl]w use 0x3f as a mask rather than 0x1f.
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8