nsz Git - libfirm/blob - ir/lower/lower_mode_b.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   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.
  10  *
  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.
  14  *
  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
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  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
  27  * @version     $Id$
  28  */
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <stdlib.h>
  34
  35 #include "irnode_t.h"
  36 #include "ircons_t.h"
  37 #include "irgwalk.h"
  38 #include "irtools.h"
  39 #include "iredges.h"
  40 #include "iropt_t.h"
  41 #include "tv.h"
  42 #include "error.h"
  43 #include "lowering.h"
  44 #include "pdeq.h"
  45
  46 static lower_mode_b_config_t  config;
  47 static ir_type               *lowered_type  = NULL;
  48 static pdeq                  *lowered_nodes = NULL;
  49
  50 /**
  51  * Removes a node if its out-edge count has reached 0.
  52  * temporary hack until we have proper automatic dead code elimination.
  53  */
  54 static void maybe_kill_node(ir_node *node)
  55 {
  56         ir_graph *irg;
  57         int       i, arity;
  58
  59         if(get_irn_n_edges(node) != 0)
  60                 return;
  61
  62         irg = get_irn_irg(node);
  63
  64         assert(!is_Bad(node));
  65
  66         arity = get_irn_arity(node);
  67         for (i = 0; i < arity; ++i) {
  68                 set_irn_n(node, i, new_Bad());
  69         }
  70         set_nodes_block(node, new_Bad());
  71
  72         edges_node_deleted(node, irg);
  73 }
  74
  75 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
  76 {
  77         ir_graph *irg    = current_ir_graph;
  78         ir_node  *block  = get_nodes_block(node);
  79         ir_mode  *mode   = config.lowered_mode;
  80         tarval   *tv_one = get_tarval_one(mode);
  81         ir_node  *one    = new_d_Const(dbgi, mode, tv_one);
  82
  83         return new_rd_Eor(dbgi, irg, block, node, one, mode);
  84 }
  85
  86 static ir_node *create_convb(ir_node *node)
  87 {
  88         ir_graph *irg   = current_ir_graph;
  89         ir_node  *block = get_nodes_block(node);
  90         ir_node  *conv  = new_rd_Conv(NULL, irg, block, node, mode_b);
  91
  92         return conv;
  93 }
  94
  95 static ir_type *create_lowered_type(void)
  96 {
  97         if(lowered_type == NULL) {
  98                 lowered_type = new_type_primitive(new_id_from_str("__lowered_mode_b"),
  99                                                   config.lowered_mode);
 100         }
 101         return lowered_type;
 102 }
 103
 104 /**
 105  * creates a "set" node that produces a 0 or 1 based on a Cmp result
 106  */
 107 static ir_node *create_set(ir_node *node)
 108 {
 109         ir_graph *irg     = current_ir_graph;
 110         dbg_info *dbgi    = get_irn_dbg_info(node);
 111         ir_mode  *mode    = config.lowered_set_mode;
 112         tarval   *tv_one  = get_tarval_one(mode);
 113         ir_node  *one     = new_d_Const(dbgi, mode, tv_one);
 114         ir_node  *block   = get_nodes_block(node);
 115         tarval   *tv_zero = get_tarval_null(mode);
 116         ir_node  *zero    = new_d_Const(dbgi, mode, tv_zero);
 117
 118         ir_node *vals[2]  = { one, zero };
 119         ir_node *set      = new_rd_Psi(dbgi, irg, block, 1, &node, vals, mode);
 120
 121         if(mode != config.lowered_mode) {
 122                 set = new_r_Conv(irg, block, set, config.lowered_mode);
 123         }
 124
 125         return set;
 126 }
 127
 128 static void adjust_method_type(ir_type *method_type)
 129 {
 130         int i;
 131         int n_params;
 132         int n_res;
 133
 134         n_params = get_method_n_params(method_type);
 135         for(i = 0; i < n_params; ++i) {
 136                 ir_type *param = get_method_param_type(method_type, i);
 137                 if(get_type_mode(param) == mode_b) {
 138                         set_method_param_type(method_type, i, create_lowered_type());
 139                 }
 140         }
 141
 142         n_res = get_method_n_ress(method_type);
 143         for(i = 0; i < n_res; ++i) {
 144                 ir_type *res_type = get_method_res_type(method_type, i);
 145                 if(get_type_mode(res_type) == mode_b) {
 146                         set_method_res_type(method_type, i, create_lowered_type());
 147                 }
 148         }
 149 }
 150
 151 static ir_node *lower_node(ir_node *node)
 152 {
 153         ir_graph *irg   = current_ir_graph;
 154         dbg_info *dbgi  = get_irn_dbg_info(node);
 155         ir_op    *op    = get_irn_op(node);
 156         ir_node  *block = get_nodes_block(node);
 157         ir_mode *mode   = config.lowered_mode;
 158         ir_node  *res;
 159
 160         assert(get_irn_mode(node) == mode_b);
 161
 162         res = get_irn_link(node);
 163         if(res != NULL)
 164                 return res;
 165
 166         /* TODO: be robust against phi-loops... */
 167         if(op == op_Phi) {
 168                 int       i, arity;
 169                 ir_node **in;
 170                 ir_node  *unknown, *new_phi;
 171
 172                 arity = get_irn_arity(node);
 173                 in    = alloca(arity * sizeof(in[0]));
 174                 unknown = new_Unknown(config.lowered_mode);
 175                 for(i = 0; i < arity; ++i) {
 176                         in[i] = unknown;
 177                 }
 178                 new_phi = new_r_Phi(irg, block, arity, in, config.lowered_mode);
 179                 set_irn_link(node, new_phi);
 180                 pdeq_putr(lowered_nodes, node);
 181
 182                 for(i = 0; i < arity; ++i) {
 183                         ir_node *in     = get_irn_n(node, i);
 184                         ir_node *low_in = lower_node(in);
 185
 186                         set_irn_n(new_phi, i, low_in);
 187                 }
 188
 189                 return new_phi;
 190         }
 191
 192         if(op == op_And || op == op_Or || op == op_Eor) {
 193                 int i, arity;
 194                 ir_node *copy = exact_copy(node);
 195
 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);
 200
 201                         set_irn_n(copy, i, low_in);
 202                 }
 203                 set_irn_mode(copy, config.lowered_mode);
 204
 205                 set_irn_link(node, copy);
 206                 pdeq_putr(lowered_nodes, node);
 207                 return copy;
 208         }
 209         if(op == op_Not) {
 210                 ir_node *op     = get_Not_op(node);
 211                 ir_node *low_op = lower_node(op);
 212
 213                 res = create_not(dbgi, low_op);
 214                 set_irn_link(node, res);
 215                 pdeq_putr(lowered_nodes, node);
 216                 return res;
 217         }
 218         if(op == op_Psi) {
 219                 ir_node *cond        = get_Psi_cond(node, 0);
 220                 ir_node *low_cond    = lower_node(cond);
 221                 ir_node *v_true      = get_Psi_val(node, 0);
 222                 ir_node *low_v_true  = lower_node(v_true);
 223                 ir_node *v_false     = get_Psi_default(node);
 224                 ir_node *low_v_false = lower_node(v_false);
 225
 226                 ir_node *and0     = new_rd_And(dbgi, irg, block, low_cond, low_v_true,
 227                                                mode);
 228
 229                 ir_node *not_cond = create_not(dbgi, low_cond);
 230
 231                 ir_node *and1     = new_rd_And(dbgi, irg, block, not_cond, low_v_false,
 232                                                mode);
 233
 234                 ir_node *or       = new_rd_Or(dbgi, irg, block, and0, and1,
 235                                               mode);
 236
 237                 set_irn_link(node, or);
 238                 pdeq_putr(lowered_nodes, node);
 239                 return or;
 240         }
 241         if(op == op_Conv) {
 242                 ir_node *pred     = get_Conv_op(node);
 243                 ir_mode *mode     = get_irn_mode(pred);
 244                 tarval  *tv_zeroc = get_tarval_null(mode);
 245                 ir_node *zero_cmp = new_d_Const(dbgi, mode, tv_zeroc);
 246                 ir_node *set;
 247
 248                 ir_node *cmp      = new_rd_Cmp(dbgi, irg, block, pred, zero_cmp);
 249                 ir_node *proj     = new_rd_Proj(dbgi, irg, block, cmp, mode_b,
 250                                                 pn_Cmp_Lg);
 251                 set = create_set(proj);
 252
 253                 set_irn_link(node, set);
 254                 pdeq_putr(lowered_nodes, node);
 255                 return set;
 256         }
 257         if(op == op_Proj) {
 258                 ir_node *pred = get_Proj_pred(node);
 259
 260                 if(is_Cmp(pred)) {
 261                         ir_node *left  = get_Cmp_left(pred);
 262                         ir_node *right = get_Cmp_right(pred);
 263                         ir_mode *cmp_mode  = get_irn_mode(left);
 264                         ir_node *set;
 265
 266                         if ((mode_is_int(cmp_mode) || mode_is_reference(cmp_mode)) && (
 267                                                 get_mode_size_bits(cmp_mode) < get_mode_size_bits(mode) ||
 268                                                 (mode_is_signed(cmp_mode) && is_Const(right) && is_Const_null(right))
 269                                         )) {
 270                                 int      pnc      = get_Proj_proj(node);
 271                                 int      need_not = 0;
 272                                 ir_node *a        = NULL;
 273                                 ir_node *b        = NULL;
 274
 275                                 if(pnc == pn_Cmp_Lt) {
 276                                         /* a < b  ->  (a - b) >> 31 */
 277                                         a = left;
 278                                         b = right;
 279                                 } else if(pnc == pn_Cmp_Le) {
 280                                         /* a <= b  -> ~(a - b) >> 31 */
 281                                         a        = right;
 282                                         b        = left;
 283                                         need_not = 1;
 284                                 } else if(pnc == pn_Cmp_Gt) {
 285                                         /* a > b   -> (b - a) >> 31 */
 286                                         a = right;
 287                                         b = left;
 288                                 } else if(pnc == pn_Cmp_Ge) {
 289                                         /* a >= b   -> ~(a - b) >> 31 */
 290                                         a        = left;
 291                                         b        = right;
 292                                         need_not = 1;
 293                                 }
 294
 295                                 if(a != NULL) {
 296                                         int      bits      = get_mode_size_bits(mode);
 297                                         tarval  *tv        = new_tarval_from_long(bits-1, mode_Iu);
 298                                         ir_node *shift_cnt = new_d_Const(dbgi, mode_Iu, tv);
 299
 300                                         if(cmp_mode != mode) {
 301                                                 a = new_rd_Conv(dbgi, irg, block, a, mode);
 302                                                 b = new_rd_Conv(dbgi, irg, block, b, mode);
 303                                         }
 304
 305                                         res = new_rd_Sub(dbgi, irg, block, a, b, mode);
 306                                         if(need_not) {
 307                                                 res = new_rd_Not(dbgi, irg, block, res, mode);
 308                                         }
 309                                         res = new_rd_Shr(dbgi, irg, block, res, shift_cnt, mode);
 310
 311                                         set_irn_link(node, res);
 312                                         pdeq_putr(lowered_nodes, node);
 313                                         return res;
 314                                 }
 315                         }
 316
 317                         /* synthesize the 0/1 value */
 318                         set = create_set(node);
 319                         set_irn_link(node, set);
 320                         pdeq_putr(lowered_nodes, node);
 321                         return set;
 322                 } else if(is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
 323                         ir_type   *type   = get_Call_type(get_Proj_pred(pred));
 324                         adjust_method_type(type);
 325                         set_irn_mode(node, mode);
 326                         return node;
 327                 } else if(is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
 328                         ir_entity *entity = get_irg_entity(irg);
 329                         ir_type   *type   = get_entity_type(entity);
 330                         adjust_method_type(type);
 331                         set_irn_mode(node, mode);
 332                         return node;
 333                 }
 334
 335                 panic("unexpected projb: %+F (pred: %+F)", node, pred);
 336         }
 337         if(op == op_Const) {
 338                 tarval *tv = get_Const_tarval(node);
 339                 if(tv == get_tarval_b_true()) {
 340                         tarval  *tv_one  = get_tarval_one(mode);
 341                         res              = new_d_Const(dbgi, mode, tv_one);
 342                 } else if(tv == get_tarval_b_false()) {
 343                         tarval  *tv_zero = get_tarval_null(mode);
 344                         res              = new_d_Const(dbgi, mode, tv_zero);
 345                 } else {
 346                         panic("invalid boolean const %+F", node);
 347                 }
 348                 set_irn_link(node, res);
 349                 pdeq_putr(lowered_nodes, node);
 350                 return res;
 351         }
 352         if (op == op_Unknown) {
 353                 return new_Unknown(config.lowered_mode);
 354         }
 355
 356         panic("didn't expect %+F to have mode_b", node);
 357 }
 358
 359 static void lower_mode_b_walker(ir_node *node, void *env)
 360 {
 361         int i, arity;
 362         int changed = 0;
 363         (void) env;
 364
 365         arity = get_irn_arity(node);
 366         for(i = 0; i < arity; ++i) {
 367                 ir_node *lowered_in;
 368                 ir_node *in = get_irn_n(node, i);
 369                 if(get_irn_mode(in) != mode_b)
 370                         continue;
 371
 372                 if(! config.lower_direct_cmp) {
 373                         if(is_Cond(node)
 374                                         || (is_Psi(node) && get_irn_mode(node) != mode_b)) {
 375                                 if(is_Proj(in)) {
 376                                         ir_node *pred = get_Proj_pred(in);
 377                                         if(is_Cmp(pred))
 378                                                 continue;
 379                                 }
 380                         }
 381                 }
 382
 383                 lowered_in = lower_node(in);
 384
 385                 if(is_Return(node)) {
 386                         ir_entity *entity = get_irg_entity(current_ir_graph);
 387                         ir_type   *type   = get_entity_type(entity);
 388                         adjust_method_type(type);
 389                 } else if(is_Call(node)) {
 390                         ir_type *type = get_Call_type(node);
 391                         adjust_method_type(type);
 392                 } else {
 393                         lowered_in = create_convb(lowered_in);
 394                 }
 395                 set_irn_n(node, i, lowered_in);
 396                 changed = 1;
 397         }
 398         if(changed) {
 399                 add_identities(current_ir_graph->value_table, node);
 400         }
 401 }
 402
 403 static void clear_links(ir_node *node, void *env)
 404 {
 405         (void) env;
 406         set_irn_link(node, NULL);
 407 }
 408
 409 void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *nconfig)
 410 {
 411         config        = *nconfig;
 412         lowered_nodes = new_pdeq();
 413         set_using_irn_link(irg);
 414
 415         irg_walk_graph(irg, clear_links, NULL, NULL);
 416         irg_walk_graph(irg, lower_mode_b_walker, NULL, NULL);
 417
 418         while(!pdeq_empty(lowered_nodes)) {
 419                 ir_node *node = (ir_node*) pdeq_getr(lowered_nodes);
 420                 maybe_kill_node(node);
 421         }
 422         del_pdeq(lowered_nodes);
 423
 424         clear_using_irn_link(irg);
 425 }