[wasm] Implement I32x4ReplaceLane, I32x4Add, I32x4Sub.

src/wasm/ast-decoder.cc

Index: src/wasm/ast-decoder.cc
diff --git a/src/wasm/ast-decoder.cc b/src/wasm/ast-decoder.cc
index 796bd9f7443412a47f0f4be1378302d00833e563..a16af97a31b75fa93f06ad35c1ed92e2e3efa2ed 100644
--- a/src/wasm/ast-decoder.cc
+++ b/src/wasm/ast-decoder.cc
@@ -1331,16 +1331,33 @@ class WasmFullDecoder : public WasmDecoder {
   unsigned ExtractLane(WasmOpcode opcode, LocalType type) {
     LaneOperand operand(this, pc_);
     if (Validate(pc_, operand)) {
-      TFNode* input = Pop(0, LocalType::kSimd128).node;
-      TFNode* node = BUILD(SimdExtractLane, opcode, operand.lane, input);
+      compiler::NodeVector inputs(1, zone_);
+      inputs[0] = Pop(0, LocalType::kSimd128).node;
+      TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
       Push(type, node);
     }
     return operand.length;
   }
 
+  unsigned ReplaceLane(WasmOpcode opcode, LocalType type) {
+    LaneOperand operand(this, pc_);
+    if (Validate(pc_, operand)) {
+      compiler::NodeVector inputs(2, zone_);
+      inputs[1] = Pop(1, type).node;
+      inputs[0] = Pop(0, LocalType::kSimd128).node;
+      TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
+      Push(LocalType::kSimd128, node);
+    }
+    return operand.length;
+  }
+
   unsigned DecodeSimdOpcode(WasmOpcode opcode) {
     unsigned len = 0;
     switch (opcode) {
+      case kExprI32x4ReplaceLane: {
+        len = ReplaceLane(opcode, LocalType::kWord32);
+        break;
+      }
       case kExprI32x4ExtractLane: {
         len = ExtractLane(opcode, LocalType::kWord32);
         break;