Convert SIMD wasm ops to runtime function calls

src/compiler/simd-lowering.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_SIMD_LOWERING_H_
+#define V8_COMPILER_SIMD_LOWERING_H_
+
+#include "src/compiler/graph-reducer.h"
+#include "src/compiler/wasm-compiler.h"
+#include "src/runtime/runtime.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Forward declarations.
+class JSGraph;
+class MachineOperatorBuilder;
+
+class SimdLowering final : public Reducer {
+ public:
+  explicit SimdLowering(WasmGraphBuilder* builder) : builder_(builder) {}
+  virtual ~SimdLowering();
+  Reduction Reduce(Node* node) override;
+
+ private:
+  WasmGraphBuilder* builder_;
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_SIMD_LOWERING_H_