i965/vec4: implement double packing

Reviewed-by: Matt Turner <mattst88@gmail.com>
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
index b94df2e..835ebdf 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
@@ -1533,6 +1533,17 @@
       break;
    }
 
+   case nir_op_pack_double_2x32_split: {
+      dst_reg result = dst_reg(this, glsl_type::dvec4_type);
+      dst_reg tmp = dst_reg(this, glsl_type::uvec4_type);
+      emit(MOV(tmp, retype(op[0], BRW_REGISTER_TYPE_UD)));
+      emit(VEC4_OPCODE_SET_LOW_32BIT, result, src_reg(tmp));
+      emit(MOV(tmp, retype(op[1], BRW_REGISTER_TYPE_UD)));
+      emit(VEC4_OPCODE_SET_HIGH_32BIT, result, src_reg(tmp));
+      emit(MOV(dst, src_reg(result)));
+      break;
+   }
+
    case nir_op_unpack_double_2x32_split_x:
    case nir_op_unpack_double_2x32_split_y: {
       enum opcode oper = (instr->op == nir_op_unpack_double_2x32_split_x) ?