[ET-VK] Nit Arithmetic cleanup

Facilitate code review before the big refactoring. Create a `maybe_prepack()` helper and improve variable naming.

Differential Revision: [D54400674](https://our.internmc.facebook.com/intern/diff/D54400674/)

[ghstack-poisoned]

Author: jorgep31415

backends/vulkan/runtime/graph/ops/impl/Arithmetic.cpp

@@ -36,44 +36,40 @@ DEFINE_ARITHMETIC_FN(pow, POW);
 
 ValueRef add_arithmetic_node(
     ComputeGraph& graph,
-    const ValueRef t1,
-    const ValueRef t2,
+    const ValueRef in1,
+    const ValueRef in2,
     const float alpha,
     const arithmetic::OpType optype,
     const int64_t shared_object_idx) {
-  std::vector<int64_t> t1_sizes = graph.get_val_sizes(t1);
-  api::ScalarType t1_dtype = graph.get_val_dtype(t1);
+  std::vector<int64_t> in1_sizes = graph.get_val_sizes(in1);
+  api::ScalarType in1_dtype = graph.get_val_dtype(in1);
 
-  ValueRef out = graph.add_tensor(t1_sizes, t1_dtype, shared_object_idx);
-  add_arithmetic_node(graph, t1, t2, out, alpha, optype);
+  ValueRef out = graph.add_tensor(in1_sizes, in1_dtype, shared_object_idx);
+  add_arithmetic_node(graph, in1, in2, out, alpha, optype);
   return out;
 }
 
+// TODO(T181006464): Move to Utils when we remove ArithmeticPrepack.
+ValueRef prepack_if_tensor_ref(ComputeGraph& graph, const ValueRef v) {
+  if (graph.get_val(v).isTensor()) {
+    return v;
+  } else {
+    TensorRef& tRef = graph.get_val(v).toTensorRef();
+    ValueRef vTen = graph.add_tensor(tRef.sizes, tRef.dtype);
+    graph.prepack_nodes().emplace_back(new ArithmeticPrepack(v, vTen));
+    return vTen;
+  }
+}
+
 void add_arithmetic_node(
     ComputeGraph& graph,
-    const ValueRef t1,
-    const ValueRef t2,
+    const ValueRef in1,
+    const ValueRef in2,
     const ValueRef out,
     const float alpha,
     const arithmetic::OpType optype) {
-  // Prepacking first arg (if needed)
-  ValueRef arg1 = t1;
-  if (graph.get_val(t1).isTensorRef()) {
-    TensorRef& t1_asref = graph.get_val(t1).toTensorRef();
-    ValueRef t1_vten = graph.add_tensor(t1_asref.sizes, t1_asref.dtype);
-    graph.prepack_nodes().emplace_back(new ArithmeticPrepack(t1, t1_vten));
-    arg1 = t1_vten;
-  }
-  VK_CHECK_COND(graph.get_val(arg1).isTensor());
-  // Prepacking second arg (if needed)
-  ValueRef arg2 = t2;
-  if (graph.get_val(t2).isTensorRef()) {
-    TensorRef& t2_asref = graph.get_val(t2).toTensorRef();
-    ValueRef t2_vten = graph.add_tensor(t2_asref.sizes, t2_asref.dtype);
-    graph.prepack_nodes().emplace_back(new ArithmeticPrepack(t2, t2_vten));
-    arg2 = t2_vten;
-  }
-  VK_CHECK_COND(graph.get_val(arg2).isTensor());
+  ValueRef arg1 = prepack_if_tensor_ref(graph, in1);
+  ValueRef arg2 = prepack_if_tensor_ref(graph, in2);
 
   graph.execute_nodes().emplace_back(
       new ArithmeticNode(arg1, arg2, out, alpha, optype));
@@ -97,12 +93,12 @@ void ArithmeticPrepack::encode(ComputeGraph* graph) const {
 }
 
 ArithmeticNode::ArithmeticNode(
-    const ValueRef t1,
-    const ValueRef t2,
+    const ValueRef in1,
+    const ValueRef in2,
     const ValueRef out,
     const float alpha,
     const arithmetic::OpType optype)
-    : ExecuteNode({t1, t2}, {out}), alpha_(alpha), optype_(optype) {}
+    : ExecuteNode({in1, in2}, {out}), alpha_(alpha), optype_(optype) {}
 
 void ArithmeticNode::encode(ComputeGraph* graph) const {
   vTensor& in1 = graph->get_val(inputs_[0]).toTensor();

backends/vulkan/runtime/graph/ops/impl/Arithmetic.h

@@ -29,16 +29,16 @@ DECLARE_OP_FN(pow);
 
 ValueRef add_arithmetic_node(
     ComputeGraph& graph,
-    const ValueRef t1,
-    const ValueRef t2,
+    const ValueRef in1,
+    const ValueRef in2,
     const float alpha,
     const arithmetic::OpType optype,
     const int64_t shared_object_idx = -1);
 
 void add_arithmetic_node(
     ComputeGraph& graph,
-    const ValueRef t1,
-    const ValueRef t2,
+    const ValueRef in1,
+    const ValueRef in2,
     const ValueRef out,
     const float alpha,
     const arithmetic::OpType optype);
@@ -53,8 +53,8 @@ class ArithmeticPrepack : public virtual PrepackNode {
 class ArithmeticNode : public virtual ExecuteNode {
  public:
   explicit ArithmeticNode(
-      const ValueRef t1,
-      const ValueRef t2,
+      const ValueRef in1,
+      const ValueRef in2,
       const ValueRef out,
       const float alpha,
       const arithmetic::OpType optype);