2 * Copyright (C) 1995-2011 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 whether ConvB(X) is a good 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;
64 static ir_node **check_later;
67 * Removes a node if its out-edge count has reached 0.
68 * temporary hack until we have proper automatic dead code elimination.
70 static void maybe_kill_node(ir_node *node)
72 if (get_irn_n_edges(node) != 0)
78 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
80 ir_node *block = get_nodes_block(node);
81 ir_mode *mode = config->lowered_mode;
82 ir_tarval *tv_one = get_mode_one(mode);
83 ir_graph *irg = get_irn_irg(node);
84 ir_node *one = new_rd_Const(dbgi, irg, tv_one);
86 return new_rd_Eor(dbgi, block, node, one, mode);
89 static ir_node *create_convb(ir_node *node)
91 ir_node *block = get_nodes_block(node);
92 ir_node *conv = new_rd_Conv(NULL, block, node, mode_b);
97 static ir_type *create_lowered_type(void)
99 if (lowered_type == NULL) {
100 lowered_type = new_type_primitive(config->lowered_mode);
105 ir_node *ir_create_mux_set(ir_node *cond, ir_mode *dest_mode)
107 ir_graph *irg = get_irn_irg(cond);
108 ir_node *block = get_nodes_block(cond);
109 ir_tarval *tv_one = get_mode_one(dest_mode);
110 ir_node *one = new_r_Const(irg, tv_one);
111 ir_tarval *tv_zero = get_mode_null(dest_mode);
112 ir_node *zero = new_r_Const(irg, tv_zero);
113 ir_node *set = new_r_Mux(block, cond, zero, one, dest_mode);
117 ir_node *ir_create_cond_set(ir_node *cond_value, ir_mode *dest_mode)
119 ir_node *lower_block = part_block_edges(cond_value);
120 ir_node *upper_block = get_nodes_block(cond_value);
121 ir_graph *irg = get_irn_irg(cond_value);
122 ir_node *cond = new_r_Cond(upper_block, cond_value);
123 ir_node *proj_true = new_r_Proj(cond, mode_X, pn_Cond_true);
124 ir_node *proj_false = new_r_Proj(cond, mode_X, pn_Cond_false);
125 ir_node *in_true[1] = { proj_true };
126 ir_node *in_false[1] = { proj_false };
127 ir_node *true_block = new_r_Block(irg, ARRAY_SIZE(in_true), in_true);
128 ir_node *false_block = new_r_Block(irg, ARRAY_SIZE(in_false),in_false);
129 ir_node *true_jmp = new_r_Jmp(true_block);
130 ir_node *false_jmp = new_r_Jmp(false_block);
131 ir_node *lower_in[2] = { true_jmp, false_jmp };
132 ir_node *one = new_r_Const(irg, get_mode_one(dest_mode));
133 ir_node *zero = new_r_Const(irg, get_mode_null(dest_mode));
134 ir_node *phi_in[2] = { one, zero };
137 set_irn_in(lower_block, ARRAY_SIZE(lower_in), lower_in);
138 phi = new_r_Phi(lower_block, ARRAY_SIZE(phi_in), phi_in, dest_mode);
140 /* make sure we do visit the cond_value later... */
141 ARR_APP1(ir_node*, check_later, cond_value);
146 static void adjust_method_type(ir_type *method_type)
152 n_params = get_method_n_params(method_type);
153 for (i = 0; i < n_params; ++i) {
154 ir_type *param = get_method_param_type(method_type, i);
155 if (get_type_mode(param) == mode_b) {
156 set_method_param_type(method_type, i, create_lowered_type());
160 n_res = get_method_n_ress(method_type);
161 for (i = 0; i < n_res; ++i) {
162 ir_type *res_type = get_method_res_type(method_type, i);
163 if (get_type_mode(res_type) == mode_b) {
164 set_method_res_type(method_type, i, create_lowered_type());
169 static ir_node *lower_node(ir_node *node)
171 dbg_info *dbgi = get_irn_dbg_info(node);
172 ir_node *block = get_nodes_block(node);
173 ir_mode *mode = config->lowered_mode;
174 ir_node *res = (ir_node*)get_irn_link(node);
180 node = skip_Tuple(node);
182 assert(get_irn_mode(node) == mode_b);
184 irg = get_irn_irg(node);
185 switch (get_irn_opcode(node)) {
192 arity = get_irn_arity(node);
193 in = ALLOCAN(ir_node*, arity);
194 dummy = new_r_Dummy(irg, mode);
195 for (i = 0; i < arity; ++i) {
198 new_phi = new_r_Phi(block, arity, in, mode);
199 /* FIXME This does not correctly break cycles: The Phi might not be the
200 * first in the recursion, so the caller(s) are some yet un-lowered
201 * nodes and this Phi might have them (indirectly) as operands, so they
202 * would be replaced twice. */
203 set_irn_link(node, new_phi);
204 ARR_APP1(ir_node*, lowered_nodes, node);
206 for (i = 0; i < arity; ++i) {
207 ir_node *in = get_irn_n(node, i);
208 ir_node *lowered_in = is_Bad(in) ? in : lower_node(in);
210 set_irn_n(new_phi, i, lowered_in);
217 ir_node *lowered_left = lower_node(get_And_left(node));
218 ir_node *lowered_right = lower_node(get_And_right(node));
219 res = new_rd_And(dbgi, block, lowered_left, lowered_right, mode);
223 ir_node *lowered_left = lower_node(get_Or_left(node));
224 ir_node *lowered_right = lower_node(get_Or_right(node));
225 res = new_rd_Or(dbgi, block, lowered_left, lowered_right, mode);
229 ir_node *lowered_left = lower_node(get_Eor_left(node));
230 ir_node *lowered_right = lower_node(get_Eor_right(node));
231 res = new_rd_Eor(dbgi, block, lowered_left, lowered_right, mode);
236 ir_node *op = get_Not_op(node);
237 ir_node *low_op = lower_node(op);
239 res = create_not(dbgi, low_op);
244 ir_node *cond = get_Mux_sel(node);
245 ir_node *low_cond = lower_node(cond);
246 ir_node *v_true = get_Mux_true(node);
247 ir_node *low_v_true = lower_node(v_true);
248 ir_node *v_false = get_Mux_false(node);
249 ir_node *low_v_false = lower_node(v_false);
251 ir_node *and0 = new_rd_And(dbgi, block, low_cond, low_v_true, mode);
252 ir_node *not_cond = create_not(dbgi, low_cond);
253 ir_node *and1 = new_rd_And(dbgi, block, not_cond, low_v_false, mode);
254 res = new_rd_Or(dbgi, block, and0, and1, mode);
259 ir_node *pred = get_Conv_op(node);
260 ir_mode *mode = get_irn_mode(pred);
261 ir_tarval *tv_zeroc = get_mode_null(mode);
262 ir_node *zero_cmp = new_rd_Const(dbgi, irg, tv_zeroc);
264 ir_node *cmp = new_rd_Cmp(dbgi, block, pred, zero_cmp, ir_relation_less_greater);
265 res = config->create_set(cmp);
270 ir_node *left = get_Cmp_left(node);
271 ir_node *right = get_Cmp_right(node);
272 ir_mode *cmp_mode = get_irn_mode(left);
273 ir_relation relation = get_Cmp_relation(node);
275 if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) &&
276 (get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
277 (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right) && relation != ir_relation_greater))) {
285 if (relation == ir_relation_less) {
286 /* a < b -> (a - b) >> 31 */
289 } else if (relation == ir_relation_less_equal) {
290 /* a <= b -> ~(a - b) >> 31 */
294 } else if (relation == ir_relation_greater) {
295 /* a > b -> (b - a) >> 31 */
298 } else if (relation == ir_relation_greater_equal) {
299 /* a >= b -> ~(a - b) >> 31 */
307 bits = get_mode_size_bits(mode);
308 tv = new_tarval_from_long(bits-1, mode_Iu);
309 shift_cnt = new_rd_Const(dbgi, irg, tv);
311 if (cmp_mode != mode) {
312 a = new_rd_Conv(dbgi, block, a, mode);
313 b = new_rd_Conv(dbgi, block, b, mode);
316 res = new_rd_Sub(dbgi, block, a, b, mode);
318 res = new_rd_Not(dbgi, block, res, mode);
320 res = new_rd_Shr(dbgi, block, res, shift_cnt, mode);
322 /* synthesize the 0/1 value */
324 res = config->create_set(node);
330 ir_node *pred = get_Proj_pred(node);
332 if (is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
333 ir_type *type = get_Call_type(get_Proj_pred(pred));
334 adjust_method_type(type);
335 set_irn_mode(node, mode);
337 goto own_replacement;
338 } else if (is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
339 ir_graph *irg = get_irn_irg(node);
340 ir_entity *entity = get_irg_entity(irg);
341 ir_type *type = get_entity_type(entity);
342 adjust_method_type(type);
343 set_irn_mode(node, mode);
345 goto own_replacement;
347 panic("unexpected projb: %+F (pred: %+F)", node, pred);
351 ir_tarval *tv = get_Const_tarval(node);
352 if (tv == get_tarval_b_true()) {
353 ir_tarval *tv_one = get_mode_one(mode);
354 res = new_rd_Const(dbgi, irg, tv_one);
355 } else if (tv == get_tarval_b_false()) {
356 ir_tarval *tv_zero = get_mode_null(mode);
357 res = new_rd_Const(dbgi, irg, tv_zero);
359 panic("invalid boolean const %+F", node);
365 res = new_r_Unknown(irg, mode);
369 panic("didn't expect %+F to have mode_b", node);
372 ARR_APP1(ir_node*, lowered_nodes, node);
374 set_irn_link(node, res);
378 static void lower_mode_b_walker(ir_node *node, void *env)
381 bool changed = false;
383 arity = get_irn_arity(node);
384 for (i = 0; i < arity; ++i) {
386 ir_node *in = get_irn_n(node, i);
387 if (get_irn_mode(in) != mode_b)
390 if (! config->lower_direct_cmp) {
391 /* Cmp as input for Cond and Mux nodes needs no changes.
392 (Mux with mode_b is an exception as it gets replaced by and/or
393 anyway so we still lower the inputs then) */
395 (is_Mux(node) && get_irn_mode(node) != mode_b)) {
402 lowered_in = lower_node(in);
405 ir_type *type = get_Call_type(node);
406 adjust_method_type(type);
407 } else if (is_Cond(node) || (is_Mux(node) && i == 0)) {
408 lowered_in = create_convb(lowered_in);
410 set_irn_n(node, i, lowered_in);
414 bool *global_changed = (bool*)env;
415 *global_changed = true;
416 add_identities(node);
420 void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *nconfig)
422 ir_entity *entity = get_irg_entity(irg);
423 ir_type *type = get_entity_type(entity);
424 bool changed = false;
429 lowered_nodes = NEW_ARR_F(ir_node*, 0);
430 check_later = NEW_ARR_F(ir_node*, 0);
435 /* ensure no optimisation touches muxes anymore */
436 set_irg_state(irg, IR_GRAPH_STATE_KEEP_MUX | IR_GRAPH_STATE_BCONV_ALLOWED);
438 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
440 adjust_method_type(type);
442 irg_walk_graph(irg, firm_clear_link, NULL, NULL);
443 irg_walk_graph(irg, lower_mode_b_walker, NULL, &changed);
445 for (i = 0, n = ARR_LEN(check_later); i < n; ++i) {
446 ir_node *node = check_later[i];
447 irg_walk_core(node, lower_mode_b_walker, NULL, &changed);
450 for (i = 0, n = ARR_LEN(lowered_nodes); i < n; ++i) {
451 ir_node *node = lowered_nodes[i];
452 maybe_kill_node(node);
454 DEL_ARR_F(check_later);
455 DEL_ARR_F(lowered_nodes);
457 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
460 /* lowering might create new blocks, so be sure to handle this */
461 set_irg_extblk_inconsistent(irg);
462 set_irg_doms_inconsistent(irg);
463 edges_deactivate(irg);