cast: remove noop op, cast in node to UnaryNode

arrayfire · umar456 · 70774a407493c2bf76792ff04d19cb7768a1ddd2
commit 70774a407493c2bf76792ff04d19cb7768a1ddd2
diff --git a/src/backend/common/cast.hpp b/src/backend/common/cast.hpp
@@ -41,32 +41,15 @@ struct CastWrapper {
         // JIT optimization in the cast of multiple sequential casts that become
         // idempotent - check to see if the previous operation was also a cast
         // TODO: handle arbitrarily long chains of casts
-        auto in_node_nary =
-            std::dynamic_pointer_cast<common::NaryNode>(in_node);
-        if (in_node_nary && in_node_nary->getOp() == af_cast_t) {
-            // The only way to get the input type of the child node if it's a
-            // cast is to get the output type of the child's child.
-            auto in_node_children = in_node_nary->getChildren();
-            // Check if any children are casts with the same type - if so,
-            // insert a shortcut noop
-            for (size_t i = 0;
-                 i < in_node_children.size() && in_node_nary->getChildren()[i];
-                 ++i) {
-                // Found a node whose child can be fast-track noop-ed
-                common::Node_ptr in_in_node = in_node_nary->getChildren()[i];
-                if (in_in_node->getType() == to_dtype) {
-                    // If the output of the child's child is the same as the
-                    // output of this node, ignore the input node and simply
-                    // connect a noop node from the child's child to produce
-                    // this op's output
-
-                    // TODO: including unary.hpp to use
-                    // detail::unaryName<af_noop_t> breaks some other stuff
-                    return detail::createNodeArray<To>(
-                        in.dims(),
-                        common::Node_ptr(new common::UnaryNode(
-                            to_dtype, "__noop", in_in_node, af_noop_t)));
-                }
+        auto in_node_unary =
+            std::dynamic_pointer_cast<common::UnaryNode>(in_node);
+        if (in_node_unary && in_node_unary->getOp() == af_cast_t) {
+            // child child's output type is the input type of the child
+            auto in_in_node = in_node_unary->getChildren()[0];
+            if (in_in_node->getType() == to_dtype) {
+                // ignore the input node and simply connect a noop node from the
+                // child's child to produce this op's output
+                return detail::createNodeArray<To>(in.dims(), in_in_node);
             }
         }