Support ComputeFn where output type differs from input type (#1771)

This is useful for e.g. function taking in 2 float inputs and turn them to complex

Author: tridao

include/cutlass/epilogue/fusion/sm90_visitor_compute_tma_warpspecialized.hpp

@@ -181,14 +181,20 @@ struct Sm90Compute {
         },
         [&] (auto&&... cvt_frg_inputs) {
           using ComputeOutput = ComputeFn<Array<ElementCompute, FragmentSize>>;
-          using ConvertOutput = NumericArrayConverter<ElementOutput, ElementCompute, FragmentSize, RoundStyle>;
           ComputeOutput compute_output{};
-          ConvertOutput convert_output{};
 
           if constexpr (cute::is_same_v<Arguments, EmptyArguments>) {
+            using ElementComputeOutput =
+                typename cute::remove_cvref_t<decltype(compute_output(cvt_frg_inputs...))>::Element;
+            using ConvertOutput = NumericArrayConverter<ElementOutput, ElementComputeOutput, FragmentSize, RoundStyle>;
+            ConvertOutput convert_output{};
             return convert_output(compute_output(cvt_frg_inputs...));
           }
           else {
+            using ElementComputeOutput =
+                typename cute::remove_cvref_t<decltype(compute_output(cvt_frg_inputs..., params))>::Element;
+            using ConvertOutput = NumericArrayConverter<ElementOutput, ElementComputeOutput, FragmentSize, RoundStyle>;
+            ConvertOutput convert_output{};
             return convert_output(compute_output(cvt_frg_inputs..., params));
           }
         }