Convert SIMD wasm ops to runtime function calls

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 facdab62eeecd7c568dc33180daee24dca7e1a88..88e70cbf17e5062a88f18ccb47172e6c12047a17 100644
--- a/src/wasm/ast-decoder.cc
+++ b/src/wasm/ast-decoder.cc
@@ -1019,6 +1019,15 @@ class WasmFullDecoder : public WasmDecoder {
             len = 1 + operand.length;
             break;
           }
+          case kSimdPrefix: {
+            if (FLAG_wasm_simd_prototype) {
+              len++;
+              byte simd_index = *(pc_ + 1);
+              opcode = static_cast<WasmOpcode>(opcode << 8 | simd_index);
+              DecodeSimdOpcode(opcode);
+              break;
+            }
+          }
           case kExprJITSingleFunction: {
             if (FLAG_wasm_jit_prototype) {
               JITSingleFunctionOperand operand(this, pc_);
@@ -1139,6 +1148,17 @@ class WasmFullDecoder : public WasmDecoder {
     return 1 + operand.length;
   }
 
+  void DecodeSimdOpcode(WasmOpcode opcode) {
+    FunctionSig* sig = WasmOpcodes::Signature(opcode);
+    compiler::NodeVector inputs(sig->parameter_count(), zone_);
+    for (size_t i = sig->parameter_count(); i > 0; i--) {
+      Value val = Pop(static_cast<int>(i - 1), sig->GetParam(i - 1));
+      inputs[i - 1] = val.node;
+    }
+    TFNode* node = BUILD(SimdOp, opcode, inputs);
+    Push(GetReturnType(sig), node);
+  }
+
   void DoReturn() {
     int count = static_cast<int>(sig_->return_count());
     TFNode** buffer = nullptr;