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
29 * After this pass the following should hold:
30 * - The only inputs with mode_b are for the Cond node or the
31 * Sel input of a Mux node.
32 * - The only nodes producing mode_b are: Proj(Cmp) and ConvB(X) (where X
33 * is some mode that can be converted to the lowered mode).
34 * ConvB will usually be implemented by a comparison with 0 producing some
35 * flags in the backends. It's debatable wether ConvB(X) is a goode idea.
36 * Maybe we should rather introduce a Test node.
37 * All other former uses should be converted to manipulations with an integer
38 * mode that was specified in the pass configuration.
61 static const lower_mode_b_config_t *config;
62 static ir_type *lowered_type;
63 static ir_node **lowered_nodes;
66 * Removes a node if its out-edge count has reached 0.
67 * temporary hack until we have proper automatic dead code elimination.
69 static void maybe_kill_node(ir_node *node)
74 if (get_irn_n_edges(node) != 0)
77 irg = get_irn_irg(node);
79 assert(!is_Bad(node));
81 arity = get_irn_arity(node);
82 for (i = 0; i < arity; ++i) {
83 set_irn_n(node, i, new_r_Bad(irg));
85 set_nodes_block(node, new_r_Bad(irg));
87 edges_node_deleted(node, irg);
90 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
92 ir_node *block = get_nodes_block(node);
93 ir_mode *mode = config->lowered_mode;
94 tarval *tv_one = get_mode_one(mode);
95 ir_graph *irg = get_irn_irg(node);
96 ir_node *one = new_rd_Const(dbgi, irg, tv_one);
98 return new_rd_Eor(dbgi, block, node, one, mode);
101 static ir_node *create_convb(ir_node *node)
103 ir_node *block = get_nodes_block(node);
104 ir_node *conv = new_rd_Conv(NULL, block, node, mode_b);
109 static ir_type *create_lowered_type(void)
111 if (lowered_type == NULL) {
112 lowered_type = new_type_primitive(config->lowered_mode);
117 ir_node *ir_create_mux_set(ir_node *cond, ir_mode *dest_mode)
119 ir_graph *irg = get_irn_irg(cond);
120 ir_node *block = get_nodes_block(cond);
121 tarval *tv_one = get_mode_one(dest_mode);
122 ir_node *one = new_r_Const(irg, tv_one);
123 tarval *tv_zero = get_mode_null(dest_mode);
124 ir_node *zero = new_r_Const(irg, tv_zero);
125 ir_node *set = new_r_Mux(block, cond, zero, one, dest_mode);
129 ir_node *ir_create_cond_set(ir_node *cond_value, ir_mode *dest_mode)
131 ir_node *lower_block = part_block_edges(cond_value);
132 ir_node *upper_block = get_nodes_block(cond_value);
133 ir_graph *irg = get_irn_irg(cond_value);
134 ir_node *cond = new_r_Cond(upper_block, cond_value);
135 ir_node *proj_true = new_r_Proj(cond, mode_X, pn_Cond_true);
136 ir_node *proj_false = new_r_Proj(cond, mode_X, pn_Cond_false);
137 ir_node *in_true[1] = { proj_true };
138 ir_node *in_false[1] = { proj_false };
139 ir_node *true_block = new_r_Block(irg, ARRAY_SIZE(in_true), in_true);
140 ir_node *false_block = new_r_Block(irg, ARRAY_SIZE(in_false),in_false);
141 ir_node *true_jmp = new_r_Jmp(true_block);
142 ir_node *false_jmp = new_r_Jmp(false_block);
143 ir_node *lower_in[2] = { true_jmp, false_jmp };
144 ir_node *one = new_r_Const(irg, get_mode_one(dest_mode));
145 ir_node *zero = new_r_Const(irg, get_mode_null(dest_mode));
146 ir_node *phi_in[2] = { one, zero };
149 set_irn_in(lower_block, ARRAY_SIZE(lower_in), lower_in);
150 phi = new_r_Phi(lower_block, ARRAY_SIZE(phi_in), phi_in, dest_mode);
151 assert(get_Block_phis(lower_block) == NULL);
152 set_Block_phis(lower_block, phi);
153 set_Phi_next(phi, NULL);
158 static void adjust_method_type(ir_type *method_type)
164 n_params = get_method_n_params(method_type);
165 for (i = 0; i < n_params; ++i) {
166 ir_type *param = get_method_param_type(method_type, i);
167 if (get_type_mode(param) == mode_b) {
168 set_method_param_type(method_type, i, create_lowered_type());
172 n_res = get_method_n_ress(method_type);
173 for (i = 0; i < n_res; ++i) {
174 ir_type *res_type = get_method_res_type(method_type, i);
175 if (get_type_mode(res_type) == mode_b) {
176 set_method_res_type(method_type, i, create_lowered_type());
181 static ir_node *lower_node(ir_node *node)
183 dbg_info *dbgi = get_irn_dbg_info(node);
184 ir_node *block = get_nodes_block(node);
185 ir_mode *mode = config->lowered_mode;
189 res = get_irn_link(node);
193 assert(get_irn_mode(node) == mode_b);
195 irg = get_irn_irg(node);
196 switch (get_irn_opcode(node)) {
200 ir_node *unknown, *new_phi;
202 arity = get_irn_arity(node);
203 in = ALLOCAN(ir_node*, arity);
204 unknown = new_r_Unknown(irg, mode);
205 for (i = 0; i < arity; ++i) {
208 new_phi = new_r_Phi(block, arity, in, mode);
209 /* FIXME This does not correctly break cycles: The Phi might not be the
210 * first in the recursion, so the caller(s) are some yet un-lowered
211 * nodes and this Phi might have them (indirectly) as operands, so they
212 * would be replaced twice. */
213 set_irn_link(node, new_phi);
214 ARR_APP1(ir_node*, lowered_nodes, node);
216 for (i = 0; i < arity; ++i) {
217 ir_node *in = get_irn_n(node, i);
218 ir_node *low_in = lower_node(in);
220 set_irn_n(new_phi, i, low_in);
231 res = exact_copy(node);
232 arity = get_irn_arity(node);
233 for (i = 0; i < arity; ++i) {
234 ir_node *in = get_irn_n(node, i);
235 ir_node *low_in = lower_node(in);
237 set_irn_n(res, i, low_in);
239 set_irn_mode(res, mode);
244 ir_node *op = get_Not_op(node);
245 ir_node *low_op = lower_node(op);
247 res = create_not(dbgi, low_op);
252 ir_node *cond = get_Mux_sel(node);
253 ir_node *low_cond = lower_node(cond);
254 ir_node *v_true = get_Mux_true(node);
255 ir_node *low_v_true = lower_node(v_true);
256 ir_node *v_false = get_Mux_false(node);
257 ir_node *low_v_false = lower_node(v_false);
259 ir_node *and0 = new_rd_And(dbgi, block, low_cond, low_v_true, mode);
260 ir_node *not_cond = create_not(dbgi, low_cond);
261 ir_node *and1 = new_rd_And(dbgi, block, not_cond, low_v_false, mode);
262 res = new_rd_Or(dbgi, block, and0, and1, mode);
267 ir_node *pred = get_Conv_op(node);
268 ir_mode *mode = get_irn_mode(pred);
269 tarval *tv_zeroc = get_mode_null(mode);
270 ir_node *zero_cmp = new_rd_Const(dbgi, irg, tv_zeroc);
272 ir_node *cmp = new_rd_Cmp(dbgi, block, pred, zero_cmp);
273 ir_node *proj = new_rd_Proj(dbgi, cmp, mode_b, pn_Cmp_Lg);
274 res = config->create_set(proj);
279 ir_node *pred = get_Proj_pred(node);
282 ir_node *left = get_Cmp_left(pred);
283 ir_node *right = get_Cmp_right(pred);
284 ir_mode *cmp_mode = get_irn_mode(left);
286 if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) &&
287 (get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
288 (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right)))) {
289 int pnc = get_Proj_proj(node);
297 if (pnc == pn_Cmp_Lt) {
298 /* a < b -> (a - b) >> 31 */
301 } else if (pnc == pn_Cmp_Le) {
302 /* a <= b -> ~(a - b) >> 31 */
306 } else if (pnc == pn_Cmp_Gt) {
307 /* a > b -> (b - a) >> 31 */
310 } else if (pnc == pn_Cmp_Ge) {
311 /* a >= b -> ~(a - b) >> 31 */
319 bits = get_mode_size_bits(mode);
320 tv = new_tarval_from_long(bits-1, mode_Iu);
321 shift_cnt = new_rd_Const(dbgi, irg, tv);
323 if (cmp_mode != mode) {
324 a = new_rd_Conv(dbgi, block, a, mode);
325 b = new_rd_Conv(dbgi, block, b, mode);
328 res = new_rd_Sub(dbgi, block, a, b, mode);
330 res = new_rd_Not(dbgi, block, res, mode);
332 res = new_rd_Shr(dbgi, block, res, shift_cnt, mode);
334 /* synthesize the 0/1 value */
336 res = config->create_set(node);
338 } else if (is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
339 ir_type *type = get_Call_type(get_Proj_pred(pred));
340 adjust_method_type(type);
341 set_irn_mode(node, mode);
343 goto own_replacement;
344 } else if (is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
345 ir_graph *irg = get_irn_irg(node);
346 ir_entity *entity = get_irg_entity(irg);
347 ir_type *type = get_entity_type(entity);
348 adjust_method_type(type);
349 set_irn_mode(node, mode);
351 goto own_replacement;
353 panic("unexpected projb: %+F (pred: %+F)", node, pred);
359 tarval *tv = get_Const_tarval(node);
360 if (tv == get_tarval_b_true()) {
361 tarval *tv_one = get_mode_one(mode);
362 res = new_rd_Const(dbgi, irg, tv_one);
363 } else if (tv == get_tarval_b_false()) {
364 tarval *tv_zero = get_mode_null(mode);
365 res = new_rd_Const(dbgi, irg, tv_zero);
367 panic("invalid boolean const %+F", node);
373 res = new_r_Unknown(irg, mode);
377 panic("didn't expect %+F to have mode_b", node);
380 ARR_APP1(ir_node*, lowered_nodes, node);
382 set_irn_link(node, res);
386 static void lower_mode_b_walker(ir_node *node, void *env)
389 bool changed = false;
391 arity = get_irn_arity(node);
392 for (i = 0; i < arity; ++i) {
394 ir_node *in = get_irn_n(node, i);
395 if (get_irn_mode(in) != mode_b)
398 if (! config->lower_direct_cmp) {
399 /* Proj(Cmp) as input for Cond and Mux nodes needs no changes.
400 (Mux with mode_b is an exception as it gets replaced by and/or
401 anyway so we still lower the inputs then) */
403 (is_Mux(node) && get_irn_mode(node) != mode_b)) {
405 ir_node *pred = get_Proj_pred(in);
412 lowered_in = lower_node(in);
415 ir_type *type = get_Call_type(node);
416 adjust_method_type(type);
417 } else if (is_Cond(node) || (is_Mux(node) && i == 0)) {
418 lowered_in = create_convb(lowered_in);
420 set_irn_n(node, i, lowered_in);
424 bool *global_changed = env;
425 *global_changed = true;
426 add_identities(node);
430 void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *nconfig)
432 ir_entity *entity = get_irg_entity(irg);
433 ir_type *type = get_entity_type(entity);
434 bool changed = false;
439 lowered_nodes = NEW_ARR_F(ir_node*, 0);
444 /* ensure no optimisation touches muxes anymore */
445 set_irg_state(irg, IR_GRAPH_STATE_KEEP_MUX | IR_GRAPH_STATE_BCONV_ALLOWED);
447 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
449 adjust_method_type(type);
451 irg_walk_graph(irg, firm_clear_link, NULL, NULL);
452 irg_walk_graph(irg, lower_mode_b_walker, NULL, &changed);
454 n = ARR_LEN(lowered_nodes);
455 for (i = 0; i < n; ++i) {
456 ir_node *node = lowered_nodes[i];
457 maybe_kill_node(node);
459 DEL_ARR_F(lowered_nodes);
461 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
464 set_irg_outs_inconsistent(irg);