nir: Support deref instructions in lower_var_copies

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Acked-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/nir/nir.h

@@ -78,6 +78,7 @@ name(const in_type *parent)                             \
 struct nir_function;
 struct nir_shader;
 struct nir_instr;
+struct nir_builder;
 
 
 /**
@@ -2699,6 +2700,8 @@ bool nir_lower_deref_instrs(nir_shader *shader,
                             enum nir_lower_deref_flags flags);
 
 void nir_lower_var_copy_instr(nir_intrinsic_instr *copy, nir_shader *shader);
+void nir_lower_deref_copy_instr(struct nir_builder *b,
+                                nir_intrinsic_instr *copy);
 bool nir_lower_var_copies(nir_shader *shader);
 
 void nir_fixup_deref_modes(nir_shader *shader);