+static tarval *create_bitfield_mask(ir_mode *mode, int offset, int size)
+{
+ tarval *all_one = get_mode_all_one(mode);
+ int mode_size = get_mode_size_bits(mode);
+
+ assert(offset >= 0 && size >= 0);
+ assert(offset + size <= mode_size);
+ if(size == mode_size) {
+ return all_one;
+ }
+
+ long shiftr = get_mode_size_bits(mode) - size;
+ long shiftl = offset;
+ tarval *tv_shiftr = new_tarval_from_long(shiftr, mode_uint);
+ tarval *tv_shiftl = new_tarval_from_long(shiftl, mode_uint);
+ tarval *mask0 = tarval_shr(all_one, tv_shiftr);
+ tarval *mask1 = tarval_shl(mask0, tv_shiftl);
+
+ return mask1;
+}
+
+static void bitfield_store_to_firm(const unary_expression_t *expression,
+ ir_node *value)
+{
+ expression_t *select = expression->value;
+ assert(select->kind == EXPR_SELECT);
+ type_t *type = select->base.type;
+ assert(type->kind == TYPE_BITFIELD);
+ ir_mode *mode = get_ir_mode(type->bitfield.base_type);
+ ir_node *addr = expression_to_addr(select);
+
+ assert(get_irn_mode(value) == mode);
+
+ dbg_info *dbgi = get_dbg_info(&expression->base.source_position);
+
+ /* kill upper bits of value and shift to right position */
+ ir_entity *entity = select->select.compound_entry->v.entity;
+ int bitoffset = get_entity_offset_bits_remainder(entity);
+ ir_type *entity_type = get_entity_type(entity);
+ int bitsize = get_mode_size_bits(get_type_mode(entity_type));
+
+ tarval *mask = create_bitfield_mask(mode, 0, bitsize);
+ ir_node *mask_node = new_d_Const(dbgi, mode, mask);
+ ir_node *value_masked = new_d_And(dbgi, value, mask_node, mode);
+ tarval *shiftl = new_tarval_from_long(bitoffset, mode_uint);
+ ir_node *shiftcount = new_d_Const(dbgi, mode_uint, shiftl);
+ ir_node *value_maskshift = new_d_Shl(dbgi, value_masked, shiftcount, mode);
+
+ /* load current value */
+ ir_node *mem = get_store();
+ ir_node *load = new_d_Load(dbgi, mem, addr, mode);
+ ir_node *load_mem = new_d_Proj(dbgi, load, mode_M, pn_Load_M);
+ ir_node *load_res = new_d_Proj(dbgi, load, mode, pn_Load_res);
+ tarval *shift_mask = create_bitfield_mask(mode, bitoffset, bitsize);
+ tarval *inv_mask = tarval_not(shift_mask);
+ ir_node *inv_mask_node = new_d_Const(dbgi, mode, inv_mask);
+ ir_node *load_res_masked = new_d_And(dbgi, load_res, inv_mask_node, mode);
+
+ /* construct new value and store */
+ ir_node *new_val = new_d_Or(dbgi, load_res_masked, value_maskshift, mode);
+ ir_node *store = new_d_Store(dbgi, load_mem, addr, new_val);
+ ir_node *store_mem = new_d_Proj(dbgi, store, mode_M, pn_Store_M);
+ set_store(store_mem);
+
+ if(type->base.qualifiers & TYPE_QUALIFIER_VOLATILE) {
+ set_Load_volatility(load, volatility_is_volatile);
+ set_Store_volatility(store, volatility_is_volatile);
+ }
+}
+