[turbofan] Introduce a SpeculativeToNumber operator.

src/compiler/bytecode-graph-builder.h

 // Copyright 2015 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_BYTECODE_GRAPH_BUILDER_H_
 #define V8_COMPILER_BYTECODE_GRAPH_BUILDER_H_
 
 #include "src/compiler/bytecode-analysis.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-type-hint-lowering.h"
@@ skipping 162 matching lines @@
   void BuildTestingOp(const Operator* op);
   void BuildDelete(LanguageMode language_mode);
   void BuildCastOperator(const Operator* op);
 
   // Optional early lowering to the simplified operator level. Returns the node
   // representing the lowered operation or {nullptr} if no lowering available.
   // Note that the result has already been wired into the environment just like
   // any other invocation of {NewNode} would do.
   Node* TryBuildSimplifiedBinaryOp(const Operator* op, Node* left, Node* right,
                                    FeedbackSlot slot);
+  Node* TryBuildSimplifiedToNumber(Node* input, FeedbackSlot slot);
   Node* TryBuildSimplifiedLoadNamed(const Operator* op, Node* receiver,
                                     FeedbackSlot slot);
   Node* TryBuildSimplifiedLoadKeyed(const Operator* op, Node* receiver,
                                     Node* key, FeedbackSlot slot);
   Node* TryBuildSimplifiedStoreNamed(const Operator* op, Node* receiver,
                                      Node* value, FeedbackSlot slot);
   Node* TryBuildSimplifiedStoreKeyed(const Operator* op, Node* receiver,
                                      Node* key, Node* value, FeedbackSlot slot);
 
   // Applies the given early reduction onto the current environment.
@@ skipping 171 matching lines @@
   static int const kBinaryOperationSmiHintIndex = 2;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeGraphBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_BYTECODE_GRAPH_BUILDER_H_