2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief lowers operations with mode_b. The result is a graph which
23 * might still contains some convs from/to mode_b, but no
24 * operations are performed on them anymore, they are just there
25 * so modes match. A backend can safely skip all mode_b convs.
26 * @author Matthias Braun, Christoph Mallon
45 static lower_mode_b_config_t config;
46 static ir_type *lowered_type = NULL;
47 static pdeq *lowered_nodes = NULL;
50 * Removes a node if its out-edge count has reached 0.
51 * temporary hack until we have proper automatic dead code elimination.
53 static void maybe_kill_node(ir_node *node)
58 if(get_irn_n_edges(node) != 0)
61 irg = get_irn_irg(node);
63 assert(!is_Bad(node));
65 arity = get_irn_arity(node);
66 for (i = 0; i < arity; ++i) {
67 set_irn_n(node, i, new_Bad());
69 set_nodes_block(node, new_Bad());
71 edges_node_deleted(node, irg);
74 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
76 ir_graph *irg = current_ir_graph;
77 ir_node *block = get_nodes_block(node);
78 ir_mode *mode = config.lowered_mode;
79 tarval *tv_one = get_tarval_one(mode);
80 ir_node *one = new_d_Const(dbgi, tv_one);
82 return new_rd_Eor(dbgi, irg, block, node, one, mode);
85 static ir_node *create_convb(ir_node *node)
87 ir_graph *irg = current_ir_graph;
88 ir_node *block = get_nodes_block(node);
89 ir_node *conv = new_rd_Conv(NULL, irg, block, node, mode_b);
94 static ir_type *create_lowered_type(void)
96 if(lowered_type == NULL) {
97 lowered_type = new_type_primitive(new_id_from_str("__lowered_mode_b"),
104 * creates a "set" node that produces a 0 or 1 based on a Cmp result
106 static ir_node *create_set(ir_node *node)
108 ir_graph *irg = current_ir_graph;
109 dbg_info *dbgi = get_irn_dbg_info(node);
110 ir_mode *mode = config.lowered_set_mode;
111 tarval *tv_one = get_tarval_one(mode);
112 ir_node *one = new_d_Const(dbgi, tv_one);
113 ir_node *block = get_nodes_block(node);
114 tarval *tv_zero = get_tarval_null(mode);
115 ir_node *zero = new_d_Const(dbgi, tv_zero);
117 /* ensure no optimisation touches muxes anymore */
118 set_irg_state(irg, IR_GRAPH_STATE_KEEP_MUX);
120 ir_node *set = new_rd_Mux(dbgi, irg, block, node, zero, one, mode);
122 if (mode != config.lowered_mode) {
123 set = new_r_Conv(irg, block, set, config.lowered_mode);
129 static void adjust_method_type(ir_type *method_type)
135 n_params = get_method_n_params(method_type);
136 for(i = 0; i < n_params; ++i) {
137 ir_type *param = get_method_param_type(method_type, i);
138 if(get_type_mode(param) == mode_b) {
139 set_method_param_type(method_type, i, create_lowered_type());
143 n_res = get_method_n_ress(method_type);
144 for(i = 0; i < n_res; ++i) {
145 ir_type *res_type = get_method_res_type(method_type, i);
146 if(get_type_mode(res_type) == mode_b) {
147 set_method_res_type(method_type, i, create_lowered_type());
152 static ir_node *lower_node(ir_node *node)
154 ir_graph *irg = current_ir_graph;
155 dbg_info *dbgi = get_irn_dbg_info(node);
156 ir_node *block = get_nodes_block(node);
157 ir_mode *mode = config.lowered_mode;
160 assert(get_irn_mode(node) == mode_b);
162 res = get_irn_link(node);
166 /* TODO: be robust against phi-loops... */
167 switch (get_irn_opcode(node)) {
171 ir_node *unknown, *new_phi;
173 arity = get_irn_arity(node);
174 in = ALLOCAN(ir_node*, arity);
175 unknown = new_Unknown(config.lowered_mode);
176 for(i = 0; i < arity; ++i) {
179 new_phi = new_r_Phi(irg, block, arity, in, config.lowered_mode);
180 set_irn_link(node, new_phi);
181 pdeq_putr(lowered_nodes, node);
183 for(i = 0; i < arity; ++i) {
184 ir_node *in = get_irn_n(node, i);
185 ir_node *low_in = lower_node(in);
187 set_irn_n(new_phi, i, low_in);
197 ir_node *copy = exact_copy(node);
199 arity = get_irn_arity(node);
200 for(i = 0; i < arity; ++i) {
201 ir_node *in = get_irn_n(node, i);
202 ir_node *low_in = lower_node(in);
204 set_irn_n(copy, i, low_in);
206 set_irn_mode(copy, config.lowered_mode);
208 set_irn_link(node, copy);
209 pdeq_putr(lowered_nodes, node);
213 ir_node *op = get_Not_op(node);
214 ir_node *low_op = lower_node(op);
216 res = create_not(dbgi, low_op);
217 set_irn_link(node, res);
218 pdeq_putr(lowered_nodes, node);
222 ir_node *cond = get_Mux_sel(node);
223 ir_node *low_cond = lower_node(cond);
224 ir_node *v_true = get_Mux_true(node);
225 ir_node *low_v_true = lower_node(v_true);
226 ir_node *v_false = get_Mux_false(node);
227 ir_node *low_v_false = lower_node(v_false);
229 ir_node *and0 = new_rd_And(dbgi, irg, block, low_cond, low_v_true, mode);
230 ir_node *not_cond = create_not(dbgi, low_cond);
231 ir_node *and1 = new_rd_And(dbgi, irg, block, not_cond, low_v_false, mode);
232 ir_node *or = new_rd_Or(dbgi, irg, block, and0, and1, mode);
234 set_irn_link(node, or);
235 pdeq_putr(lowered_nodes, node);
239 ir_node *pred = get_Conv_op(node);
240 ir_mode *mode = get_irn_mode(pred);
241 tarval *tv_zeroc = get_tarval_null(mode);
242 ir_node *zero_cmp = new_d_Const(dbgi, tv_zeroc);
245 ir_node *cmp = new_rd_Cmp(dbgi, irg, block, pred, zero_cmp);
246 ir_node *proj = new_rd_Proj(dbgi, irg, block, cmp, mode_b,
248 set = create_set(proj);
250 set_irn_link(node, set);
251 pdeq_putr(lowered_nodes, node);
255 ir_node *pred = get_Proj_pred(node);
258 ir_node *left = get_Cmp_left(pred);
259 ir_node *right = get_Cmp_right(pred);
260 ir_mode *cmp_mode = get_irn_mode(left);
263 if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) && (
264 get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
265 (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right))
267 int pnc = get_Proj_proj(node);
272 if(pnc == pn_Cmp_Lt) {
273 /* a < b -> (a - b) >> 31 */
276 } else if(pnc == pn_Cmp_Le) {
277 /* a <= b -> ~(a - b) >> 31 */
281 } else if(pnc == pn_Cmp_Gt) {
282 /* a > b -> (b - a) >> 31 */
285 } else if(pnc == pn_Cmp_Ge) {
286 /* a >= b -> ~(a - b) >> 31 */
293 int bits = get_mode_size_bits(mode);
294 tarval *tv = new_tarval_from_long(bits-1, mode_Iu);
295 ir_node *shift_cnt = new_d_Const(dbgi, tv);
297 if(cmp_mode != mode) {
298 a = new_rd_Conv(dbgi, irg, block, a, mode);
299 b = new_rd_Conv(dbgi, irg, block, b, mode);
302 res = new_rd_Sub(dbgi, irg, block, a, b, mode);
304 res = new_rd_Not(dbgi, irg, block, res, mode);
306 res = new_rd_Shr(dbgi, irg, block, res, shift_cnt, mode);
308 set_irn_link(node, res);
309 pdeq_putr(lowered_nodes, node);
314 /* synthesize the 0/1 value */
315 set = create_set(node);
316 set_irn_link(node, set);
317 pdeq_putr(lowered_nodes, node);
319 } else if(is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
320 ir_type *type = get_Call_type(get_Proj_pred(pred));
321 adjust_method_type(type);
322 set_irn_mode(node, mode);
324 } else if(is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
325 ir_entity *entity = get_irg_entity(irg);
326 ir_type *type = get_entity_type(entity);
327 adjust_method_type(type);
328 set_irn_mode(node, mode);
332 panic("unexpected projb: %+F (pred: %+F)", node, pred);
335 tarval *tv = get_Const_tarval(node);
336 if(tv == get_tarval_b_true()) {
337 tarval *tv_one = get_tarval_one(mode);
338 res = new_d_Const(dbgi, tv_one);
339 } else if(tv == get_tarval_b_false()) {
340 tarval *tv_zero = get_tarval_null(mode);
341 res = new_d_Const(dbgi, tv_zero);
343 panic("invalid boolean const %+F", node);
345 set_irn_link(node, res);
346 pdeq_putr(lowered_nodes, node);
350 return new_Unknown(config.lowered_mode);
352 panic("didn't expect %+F to have mode_b", node);
356 static void lower_mode_b_walker(ir_node *node, void *env)
362 arity = get_irn_arity(node);
363 for(i = 0; i < arity; ++i) {
365 ir_node *in = get_irn_n(node, i);
366 if(get_irn_mode(in) != mode_b)
369 if(! config.lower_direct_cmp) {
371 (is_Mux(node) && get_irn_mode(node) != mode_b)) {
373 ir_node *pred = get_Proj_pred(in);
380 lowered_in = lower_node(in);
382 if(is_Return(node)) {
383 ir_entity *entity = get_irg_entity(current_ir_graph);
384 ir_type *type = get_entity_type(entity);
385 adjust_method_type(type);
386 } else if(is_Call(node)) {
387 ir_type *type = get_Call_type(node);
388 adjust_method_type(type);
390 lowered_in = create_convb(lowered_in);
392 set_irn_n(node, i, lowered_in);
396 add_identities(current_ir_graph->value_table, node);
400 static void clear_links(ir_node *node, void *env)
403 set_irn_link(node, NULL);
406 void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *nconfig)
409 lowered_nodes = new_pdeq();
411 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
413 set_opt_allow_conv_b(0);
414 irg_walk_graph(irg, clear_links, NULL, NULL);
415 irg_walk_graph(irg, lower_mode_b_walker, NULL, NULL);
417 while(!pdeq_empty(lowered_nodes)) {
418 ir_node *node = (ir_node*) pdeq_getr(lowered_nodes);
419 maybe_kill_node(node);
421 del_pdeq(lowered_nodes);
423 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);