[turbofan] Properly represent the float64 hole.

src/compiler/typed-optimization.h

 // Copyright 2016 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.
 
 #ifndef V8_COMPILER_TYPED_OPTIMIZATION_H_
 #define V8_COMPILER_TYPED_OPTIMIZATION_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/base/flags.h"
 #include "src/compiler/graph-reducer.h"
@@ skipping 26 matching lines @@
 
   TypedOptimization(Editor* editor, CompilationDependencies* dependencies,
                     Flags flags, JSGraph* jsgraph);
   ~TypedOptimization();
 
   Reduction Reduce(Node* node) final;
 
  private:
   Reduction ReduceCheckHeapObject(Node* node);
   Reduction ReduceCheckMaps(Node* node);
+  Reduction ReduceCheckNumber(Node* node);
   Reduction ReduceCheckString(Node* node);
   Reduction ReduceLoadField(Node* node);
   Reduction ReduceNumberFloor(Node* node);
   Reduction ReduceNumberRoundop(Node* node);
   Reduction ReduceNumberToUint8Clamped(Node* node);
   Reduction ReducePhi(Node* node);
   Reduction ReduceReferenceEqual(Node* node);
   Reduction ReduceSelect(Node* node);
   Reduction ReduceSpeculativeToNumber(Node* node);
 
@@ skipping 15 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(TypedOptimization);
 };
 
 DEFINE_OPERATORS_FOR_FLAGS(TypedOptimization::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_TYPED_OPTIMIZATION_H_