[turbofan] Introduce dedicated ObjectIsNaN operator.

src/compiler/simplified-lowering.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/simplified-lowering.h"
 
 #include <limits>
 
 #include "src/address-map.h"
 #include "src/base/bits.h"
@@ skipping 2527 matching lines @@
           }
         } else {
           VisitUnop(node, UseInfo::AnyTagged(), MachineRepresentation::kTagged);
         }
         return;
       }
       case IrOpcode::kObjectIsDetectableCallable: {
         VisitObjectIs(node, Type::DetectableCallable(), lowering);
         return;
       }
+      case IrOpcode::kObjectIsNaN: {
+        Type* const input_type = GetUpperBound(node->InputAt(0));
+        if (input_type->Is(Type::NaN())) {
+          VisitUnop(node, UseInfo::None(), MachineRepresentation::kBit);
+          if (lower()) {
+            DeferReplacement(node, lowering->jsgraph()->Int32Constant(1));
+          }
+        } else if (!input_type->Maybe(Type::NaN())) {
+          VisitUnop(node, UseInfo::Any(), MachineRepresentation::kBit);
+          if (lower()) {
+            DeferReplacement(node, lowering->jsgraph()->Int32Constant(0));
+          }
+        } else if (input_type->Is(Type::Number())) {
+          VisitUnop(node, UseInfo::TruncatingFloat64(),
+                    MachineRepresentation::kBit);
+          if (lower()) {
+            // ObjectIsNaN(x:kRepFloat64) => Word32Equal(Float64Equal(x,x),#0)
+            Node* const input = node->InputAt(0);
+            node->ReplaceInput(
+                0, jsgraph_->graph()->NewNode(
+                       lowering->machine()->Float64Equal(), input, input));
+            node->AppendInput(jsgraph_->zone(), jsgraph_->Int32Constant(0));
+            NodeProperties::ChangeOp(node, lowering->machine()->Word32Equal());
+          }
+        } else {
+          VisitUnop(node, UseInfo::AnyTagged(), MachineRepresentation::kBit);
+        }
+        return;
+      }
       case IrOpcode::kObjectIsNonCallable: {
         VisitObjectIs(node, Type::NonCallable(), lowering);
         return;
       }
       case IrOpcode::kObjectIsNumber: {
         VisitObjectIs(node, Type::Number(), lowering);
         return;
       }
       case IrOpcode::kObjectIsReceiver: {
         VisitObjectIs(node, Type::Receiver(), lowering);
@@ skipping 982 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kNoProperties);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8