nir: Hoist nir_op_is_derivative

Redefine in terms of the algebraic property. This correctly handles the
Mali-specific derivatives.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24833>

src/compiler/nir/nir.h

@@ -1432,6 +1432,12 @@ nir_op_is_selection(nir_op op)
    return (nir_op_infos[op].algebraic_properties & NIR_OP_IS_SELECTION) != 0;
 }
 
+static inline bool
+nir_op_is_derivative(nir_op op)
+{
+   return (nir_op_infos[op].algebraic_properties & NIR_OP_IS_DERIVATIVE) != 0;
+}
+
 typedef struct nir_alu_instr {
    /** Base instruction */
    nir_instr instr;

src/compiler/nir/nir_opt_move_discards_to_top.c

@@ -26,17 +26,6 @@
 #include "nir_control_flow.h"
 #include "nir_worklist.h"
 
-static bool
-nir_op_is_derivative(nir_op op)
-{
-   return op == nir_op_fddx ||
-          op == nir_op_fddy ||
-          op == nir_op_fddx_fine ||
-          op == nir_op_fddy_fine ||
-          op == nir_op_fddx_coarse ||
-          op == nir_op_fddy_coarse;
-}
-
 static bool
 nir_texop_implies_derivative(nir_texop op)
 {