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 ir_node *set = new_rd_Mux(dbgi, irg, block, node, zero, one, mode);
119 if (mode != config.lowered_mode) {
120 set = new_r_Conv(irg, block, set, config.lowered_mode);
126 static void adjust_method_type(ir_type *method_type)
132 n_params = get_method_n_params(method_type);
133 for(i = 0; i < n_params; ++i) {
134 ir_type *param = get_method_param_type(method_type, i);
135 if(get_type_mode(param) == mode_b) {
136 set_method_param_type(method_type, i, create_lowered_type());
140 n_res = get_method_n_ress(method_type);
141 for(i = 0; i < n_res; ++i) {
142 ir_type *res_type = get_method_res_type(method_type, i);
143 if(get_type_mode(res_type) == mode_b) {
144 set_method_res_type(method_type, i, create_lowered_type());
149 static ir_node *lower_node(ir_node *node)
151 ir_graph *irg = current_ir_graph;
152 dbg_info *dbgi = get_irn_dbg_info(node);
153 ir_node *block = get_nodes_block(node);
154 ir_mode *mode = config.lowered_mode;
157 assert(get_irn_mode(node) == mode_b);
159 res = get_irn_link(node);
163 /* TODO: be robust against phi-loops... */
164 switch (get_irn_opcode(node)) {
168 ir_node *unknown, *new_phi;
170 arity = get_irn_arity(node);
171 in = ALLOCAN(ir_node*, arity);
172 unknown = new_Unknown(config.lowered_mode);
173 for(i = 0; i < arity; ++i) {
176 new_phi = new_r_Phi(irg, block, arity, in, config.lowered_mode);
177 set_irn_link(node, new_phi);
178 pdeq_putr(lowered_nodes, node);
180 for(i = 0; i < arity; ++i) {
181 ir_node *in = get_irn_n(node, i);
182 ir_node *low_in = lower_node(in);
184 set_irn_n(new_phi, i, low_in);
194 ir_node *copy = exact_copy(node);
196 arity = get_irn_arity(node);
197 for(i = 0; i < arity; ++i) {
198 ir_node *in = get_irn_n(node, i);
199 ir_node *low_in = lower_node(in);
201 set_irn_n(copy, i, low_in);
203 set_irn_mode(copy, config.lowered_mode);
205 set_irn_link(node, copy);
206 pdeq_putr(lowered_nodes, node);
210 ir_node *op = get_Not_op(node);
211 ir_node *low_op = lower_node(op);
213 res = create_not(dbgi, low_op);
214 set_irn_link(node, res);
215 pdeq_putr(lowered_nodes, node);
219 ir_node *cond = get_Mux_sel(node);
220 ir_node *low_cond = lower_node(cond);
221 ir_node *v_true = get_Mux_true(node);
222 ir_node *low_v_true = lower_node(v_true);
223 ir_node *v_false = get_Mux_false(node);
224 ir_node *low_v_false = lower_node(v_false);
226 ir_node *and0 = new_rd_And(dbgi, irg, block, low_cond, low_v_true, mode);
227 ir_node *not_cond = create_not(dbgi, low_cond);
228 ir_node *and1 = new_rd_And(dbgi, irg, block, not_cond, low_v_false, mode);
229 ir_node *or = new_rd_Or(dbgi, irg, block, and0, and1, mode);
231 set_irn_link(node, or);
232 pdeq_putr(lowered_nodes, node);
236 ir_node *pred = get_Conv_op(node);
237 ir_mode *mode = get_irn_mode(pred);
238 tarval *tv_zeroc = get_tarval_null(mode);
239 ir_node *zero_cmp = new_d_Const(dbgi, tv_zeroc);
242 ir_node *cmp = new_rd_Cmp(dbgi, irg, block, pred, zero_cmp);
243 ir_node *proj = new_rd_Proj(dbgi, irg, block, cmp, mode_b,
245 set = create_set(proj);
247 set_irn_link(node, set);
248 pdeq_putr(lowered_nodes, node);
252 ir_node *pred = get_Proj_pred(node);
255 ir_node *left = get_Cmp_left(pred);
256 ir_node *right = get_Cmp_right(pred);
257 ir_mode *cmp_mode = get_irn_mode(left);
260 if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) && (
261 get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
262 (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right))
264 int pnc = get_Proj_proj(node);
269 if(pnc == pn_Cmp_Lt) {
270 /* a < b -> (a - b) >> 31 */
273 } else if(pnc == pn_Cmp_Le) {
274 /* a <= b -> ~(a - b) >> 31 */
278 } else if(pnc == pn_Cmp_Gt) {
279 /* a > b -> (b - a) >> 31 */
282 } else if(pnc == pn_Cmp_Ge) {
283 /* a >= b -> ~(a - b) >> 31 */
290 int bits = get_mode_size_bits(mode);
291 tarval *tv = new_tarval_from_long(bits-1, mode_Iu);
292 ir_node *shift_cnt = new_d_Const(dbgi, tv);
294 if(cmp_mode != mode) {
295 a = new_rd_Conv(dbgi, irg, block, a, mode);
296 b = new_rd_Conv(dbgi, irg, block, b, mode);
299 res = new_rd_Sub(dbgi, irg, block, a, b, mode);
301 res = new_rd_Not(dbgi, irg, block, res, mode);
303 res = new_rd_Shr(dbgi, irg, block, res, shift_cnt, mode);
305 set_irn_link(node, res);
306 pdeq_putr(lowered_nodes, node);
311 /* synthesize the 0/1 value */
312 set = create_set(node);
313 set_irn_link(node, set);
314 pdeq_putr(lowered_nodes, node);
316 } else if(is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
317 ir_type *type = get_Call_type(get_Proj_pred(pred));
318 adjust_method_type(type);
319 set_irn_mode(node, mode);
321 } else if(is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
322 ir_entity *entity = get_irg_entity(irg);
323 ir_type *type = get_entity_type(entity);
324 adjust_method_type(type);
325 set_irn_mode(node, mode);
329 panic("unexpected projb: %+F (pred: %+F)", node, pred);
332 tarval *tv = get_Const_tarval(node);
333 if(tv == get_tarval_b_true()) {
334 tarval *tv_one = get_tarval_one(mode);
335 res = new_d_Const(dbgi, tv_one);
336 } else if(tv == get_tarval_b_false()) {
337 tarval *tv_zero = get_tarval_null(mode);
338 res = new_d_Const(dbgi, tv_zero);
340 panic("invalid boolean const %+F", node);
342 set_irn_link(node, res);
343 pdeq_putr(lowered_nodes, node);
347 return new_Unknown(config.lowered_mode);
349 panic("didn't expect %+F to have mode_b", node);
353 static void lower_mode_b_walker(ir_node *node, void *env)
359 arity = get_irn_arity(node);
360 for(i = 0; i < arity; ++i) {
362 ir_node *in = get_irn_n(node, i);
363 if(get_irn_mode(in) != mode_b)
366 if(! config.lower_direct_cmp) {
368 (is_Mux(node) && get_irn_mode(node) != mode_b)) {
370 ir_node *pred = get_Proj_pred(in);
377 lowered_in = lower_node(in);
379 if(is_Return(node)) {
380 ir_entity *entity = get_irg_entity(current_ir_graph);
381 ir_type *type = get_entity_type(entity);
382 adjust_method_type(type);
383 } else if(is_Call(node)) {
384 ir_type *type = get_Call_type(node);
385 adjust_method_type(type);
387 lowered_in = create_convb(lowered_in);
389 set_irn_n(node, i, lowered_in);
393 add_identities(current_ir_graph->value_table, node);
397 static void clear_links(ir_node *node, void *env)
400 set_irn_link(node, NULL);
403 void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *nconfig)
406 lowered_nodes = new_pdeq();
408 /* ensure no optimisation touches muxes anymore */
409 set_irg_state(irg, IR_GRAPH_STATE_KEEP_MUX);
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);