Eliminate unnecessary Convert ops when input element type is the same as output element type (#709)

src/ngraph/runtime/cpu/pass/cpu_nop_elimination.cpp

@@ -21,6 +21,7 @@
 #include <unordered_map>
 
 #include "cpu_nop_elimination.hpp"
+#include "ngraph/op/convert.hpp"
 #include "ngraph/op/pad.hpp"
 #include "ngraph/op/sum.hpp"
 
@@ -52,10 +53,23 @@ HANDLER_DECL(eliminate_sum)
     return false;
 }
 
+HANDLER_DECL(eliminate_convert)
+{
+    auto convert = std::dynamic_pointer_cast<ngraph::op::Convert>(node);
+    if (convert->get_convert_element_type() == convert->get_input_op(0)->get_element_type())
+    {
+        function->replace_node(node, node->get_input_op(0));
+        return true;
+    }
+    return false;
+}
+
 static const std::unordered_map<std::type_index,
                                 std::function<bool(const std::shared_ptr<ngraph::Function>&,
                                                    const std::shared_ptr<ngraph::Node>&)>>
-    dispatcher{{TI(ngraph::op::Pad), &eliminate_pad}, {TI(ngraph::op::Sum), &eliminate_sum}};
+    dispatcher{{TI(ngraph::op::Pad), &eliminate_pad},
+               {TI(ngraph::op::Sum), &eliminate_sum},
+               {TI(ngraph::op::Convert), &eliminate_convert}};
 
 bool ngraph::runtime::cpu::pass::CPUNopElimination::run_on_function(
     std::shared_ptr<ngraph::Function> function)