Fix a check in tfcompile codegen.

Previously, tfcompile expects the compiler to translate each resource variable
into a function argument. The MLIR bridge doesn't generated a function argument
for an unused resource variable.

Modify an existing test to test the situation.

PiperOrigin-RevId: 302083482
Change-Id: I08301e594422f655b8d4ba4bb66d69103764cc7f

tensorflow/compiler/aot/codegen.cc

@@ -170,7 +170,9 @@ Status GenArgMethods(const tf2xla::Config& config,
                      const xla::ProgramShapeProto& ps,
                      const CompileResult& compile_result, string* methods) {
   size_t num_args = ps.parameters_size();
-  if (config.feed_size() + config.variable_size() != num_args) {
+  // feed_size() + variable_size() is the maximum number of args as an
+  // implementation may not create an argument for an unused variable.
+  if (config.feed_size() + config.variable_size() < num_args) {
     return errors::InvalidArgument(
         "mismatch between feed_size(", config.feed_size(), ")+variable_size(",
         config.variable_size(), ") and num_args(", num_args, ")");

tensorflow/compiler/aot/tests/make_test_graphs.py

@@ -157,6 +157,7 @@ def tftop_k(_):
 
 def tfvariable_readonly(_):
   x = variables.Variable(1000.0, name='x')
+  unused_y = variables.Variable(1000.0, name='y')
   old_x = x.value()
   with ops.control_dependencies([old_x]):
     new_value = math_ops.add(old_x, 42.0)

tensorflow/compiler/aot/tests/test_graph_tfvariable_readonly.config.pbtxt

@@ -10,3 +10,11 @@ variable {
   type: DT_FLOAT
   readonly: true
 }
+
+variable {
+  node_name: "y"
+  shape {
+  }
+  type: DT_FLOAT
+  readonly: true
+}