[wasm] implement simd lowering for replaceLane, load, store and test for phi

src/compiler/simd-scalar-lowering.h

Index: src/compiler/simd-scalar-lowering.h
diff --git a/src/compiler/simd-scalar-lowering.h b/src/compiler/simd-scalar-lowering.h
index 39449f4b9ff54d01a82fc25cf204bab9efa23812..9ed1c557a21e297d8f5ca1e288dae46172ddb938 100644
--- a/src/compiler/simd-scalar-lowering.h
+++ b/src/compiler/simd-scalar-lowering.h
@@ -53,6 +53,12 @@ class SimdScalarLowering {
   SimdType ReplacementType(Node* node);
   void PreparePhiReplacement(Node* phi);
   void SetLoweredType(Node* node, Node* output);
+  void GetIndexNodes(Node* index, Node** new_indices);
+  void LowerLoadOp(MachineRepresentation rep, Node* node,
+                   const Operator* load_op);
+  void LowerStoreOp(MachineRepresentation rep, Node* node,
+                    const Operator* store_op, SimdType rep_type);
+  void LowerBinaryOp(Node* node, SimdType rep_type, const Operator* op);
 
   struct NodeState {
     Node* node;