[cleanup] Add operator parameter accessor for S8x16Shuffle

Bug: v8:7517, v8:9183
Change-Id: Ic9beade6893b81aaa77f9c634cbeb7444260907b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/973375
Auto-Submit: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62177}

src/compiler/backend/instruction-selector.cc

@@ -2965,7 +2965,7 @@ void InstructionSelector::CanonicalizeShuffle(bool inputs_equal,
 void InstructionSelector::CanonicalizeShuffle(Node* node, uint8_t* shuffle,
                                               bool* is_swizzle) {
   // Get raw shuffle indices.
-  memcpy(shuffle, OpParameter<uint8_t*>(node->op()), kSimd128Size);
+  memcpy(shuffle, S8x16ShuffleOf(node->op()), kSimd128Size);
   bool needs_swap;
   bool inputs_equal = GetVirtualRegister(node->InputAt(0)) ==
                       GetVirtualRegister(node->InputAt(1));

src/compiler/machine-operator.cc

@@ -1302,6 +1302,11 @@ const Operator* MachineOperatorBuilder::S8x16Shuffle(
                           2, 0, 0, 1, 0, 0, array);
 }
 
+const uint8_t* S8x16ShuffleOf(Operator const* op) {
+  DCHECK_EQ(IrOpcode::kS8x16Shuffle, op->opcode());
+  return OpParameter<const uint8_t*>(op);
+}
+
 #undef PURE_BINARY_OP_LIST_32
 #undef PURE_BINARY_OP_LIST_64
 #undef MACHINE_PURE_OP_LIST

src/compiler/machine-operator.h

@@ -112,6 +112,9 @@ MachineRepresentation AtomicStoreRepresentationOf(Operator const* op)
 
 MachineType AtomicOpType(Operator const* op) V8_WARN_UNUSED_RESULT;
 
+V8_EXPORT_PRIVATE const uint8_t* S8x16ShuffleOf(Operator const* op)
+    V8_WARN_UNUSED_RESULT;
+
 // Interface for building machine-level operators. These operators are
 // machine-level but machine-independent and thus define a language suitable
 // for generating code to run on architectures such as ia32, x64, arm, etc.

src/compiler/simd-scalar-lowering.cc

@@ -1347,7 +1347,7 @@ void SimdScalarLowering::LowerNode(Node* node) {
     }
     case IrOpcode::kS8x16Shuffle: {
       DCHECK_EQ(2, node->InputCount());
-      const uint8_t* shuffle = OpParameter<uint8_t*>(node->op());
+      const uint8_t* shuffle = S8x16ShuffleOf(node->op());
       Node** rep_left = GetReplacementsWithType(node->InputAt(0), rep_type);
       Node** rep_right = GetReplacementsWithType(node->InputAt(1), rep_type);
       Node** rep_node = zone()->NewArray<Node*>(16);