nir: add a nir_instr_def_is_register helper

This returns true if the instruction has a dest that is not an SSA value.

Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15056>

src/compiler/nir/nir.c

@@ -1476,6 +1476,43 @@ nir_instr_ssa_def(nir_instr *instr)
    unreachable("Invalid instruction type");
 }
 
+bool
+nir_instr_def_is_register(nir_instr *instr)
+{
+   switch (instr->type) {
+   case nir_instr_type_alu:
+      return !nir_instr_as_alu(instr)->dest.dest.is_ssa;
+
+   case nir_instr_type_deref:
+      return !nir_instr_as_deref(instr)->dest.is_ssa;
+
+   case nir_instr_type_tex:
+      return !nir_instr_as_tex(instr)->dest.is_ssa;
+
+   case nir_instr_type_intrinsic: {
+      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+      return nir_intrinsic_infos[intrin->intrinsic].has_dest &&
+             !intrin->dest.is_ssa;
+   }
+
+   case nir_instr_type_phi:
+      return !nir_instr_as_phi(instr)->dest.is_ssa;
+
+   case nir_instr_type_parallel_copy:
+      unreachable("Parallel copies are unsupported by this function");
+
+   case nir_instr_type_load_const:
+   case nir_instr_type_ssa_undef:
+      return false;
+
+   case nir_instr_type_call:
+   case nir_instr_type_jump:
+      return false;
+   }
+
+   unreachable("Invalid instruction type");
+}
+
 bool
 nir_foreach_phi_src_leaving_block(nir_block *block,
                                   nir_foreach_src_cb cb,

src/compiler/nir/nir.h

@@ -3947,6 +3947,7 @@ nir_cursor nir_instr_free_and_dce(nir_instr *instr);
 /** @} */
 
 nir_ssa_def *nir_instr_ssa_def(nir_instr *instr);
+bool nir_instr_def_is_register(nir_instr *instr);
 
 typedef bool (*nir_foreach_ssa_def_cb)(nir_ssa_def *def, void *state);
 typedef bool (*nir_foreach_dest_cb)(nir_dest *dest, void *state);