nsz Git - libfirm/blob - ir/be/bepeephole.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       Peephole optimisation framework keeps track of which registers contain which values
  23  * @author      Matthias Braun
  24  * @version     $Id$
  25  */
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include "bepeephole.h"
  31
  32 #include "iredges_t.h"
  33 #include "irgwalk.h"
  34 #include "irprintf.h"
  35 #include "error.h"
  36
  37 #include "beirg_t.h"
  38 #include "belive_t.h"
  39 #include "bearch_t.h"
  40 #include "benode_t.h"
  41 #include "besched_t.h"
  42 #include "bemodule.h"
  43
  44 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  45
  46 static const arch_env_t *arch_env;
  47 static be_lv_t          *lv;
  48 static ir_node          *current_node;
  49 ir_node               ***register_values;
  50
  51 static void clear_reg_value(ir_node *node)
  52 {
  53         const arch_register_t       *reg;
  54         const arch_register_class_t *cls;
  55         unsigned                     reg_idx;
  56         unsigned                     cls_idx;
  57
  58         if(!mode_is_data(get_irn_mode(node)))
  59                 return;
  60
  61         reg     = arch_get_irn_register(arch_env, node);
  62         if(reg == NULL) {
  63                 panic("No register assigned at %+F\n", node);
  64         }
  65         if(arch_register_type_is(reg, virtual))
  66                 return;
  67         cls     = arch_register_get_class(reg);
  68         reg_idx = arch_register_get_index(reg);
  69         cls_idx = arch_register_class_index(cls);
  70
  71         //assert(register_values[cls_idx][reg_idx] != NULL);
  72         DBG((dbg, LEVEL_1, "Clear Register %s\n", reg->name));
  73         register_values[cls_idx][reg_idx] = NULL;
  74 }
  75
  76 static void set_reg_value(ir_node *node)
  77 {
  78         const arch_register_t       *reg;
  79         const arch_register_class_t *cls;
  80         unsigned                     reg_idx;
  81         unsigned                     cls_idx;
  82
  83         if(!mode_is_data(get_irn_mode(node)))
  84                 return;
  85
  86         reg = arch_get_irn_register(arch_env, node);
  87         if(reg == NULL) {
  88                 panic("No register assigned at %+F\n", node);
  89         }
  90         if(arch_register_type_is(reg, virtual))
  91                 return;
  92         cls     = arch_register_get_class(reg);
  93         reg_idx = arch_register_get_index(reg);
  94         cls_idx = arch_register_class_index(cls);
  95
  96         DBG((dbg, LEVEL_1, "Set Register %s: %+F\n", reg->name, node));
  97         register_values[cls_idx][reg_idx] = node;
  98 }
  99
 100 static void clear_defs(ir_node *node)
 101 {
 102         /* clear values defined */
 103         if(get_irn_mode(node) == mode_T) {
 104                 const ir_edge_t *edge;
 105                 foreach_out_edge(node, edge) {
 106                         ir_node *proj = get_edge_src_irn(edge);
 107                         clear_reg_value(proj);
 108                 }
 109         } else {
 110                 clear_reg_value(node);
 111         }
 112 }
 113
 114 static void set_uses(ir_node *node)
 115 {
 116         int i, arity;
 117
 118         /* set values used */
 119         arity = get_irn_arity(node);
 120         for(i = 0; i < arity; ++i) {
 121                 ir_node *in = get_irn_n(node, i);
 122                 set_reg_value(in);
 123         }
 124 }
 125
 126 void be_peephole_before_exchange(const ir_node *old_node, ir_node *new_node)
 127 {
 128         const arch_register_t       *reg;
 129         const arch_register_class_t *cls;
 130         unsigned                     reg_idx;
 131         unsigned                     cls_idx;
 132
 133         DBG((dbg, LEVEL_1, "About to exchange %+F with %+F\n", old_node, new_node));
 134
 135         if(old_node == current_node) {
 136                 if(is_Proj(new_node)) {
 137                         current_node = get_Proj_pred(new_node);
 138                 } else {
 139                         current_node = new_node;
 140                 }
 141         }
 142
 143         if(!mode_is_data(get_irn_mode(old_node)))
 144                 return;
 145
 146         reg = arch_get_irn_register(arch_env, old_node);
 147         if(reg == NULL) {
 148                 panic("No register assigned at %+F\n", old_node);
 149         }
 150         cls     = arch_register_get_class(reg);
 151         reg_idx = arch_register_get_index(reg);
 152         cls_idx = arch_register_class_index(cls);
 153
 154         if(register_values[cls_idx][reg_idx] == old_node) {
 155                 register_values[cls_idx][reg_idx] = new_node;
 156         }
 157
 158         be_liveness_remove(lv, old_node);
 159 }
 160
 161 void be_peephole_after_exchange(ir_node *new_node)
 162 {
 163         be_liveness_introduce(lv, new_node);
 164 }
 165
 166 static void process_block(ir_node *block, void *data)
 167 {
 168         unsigned n_classes;
 169         unsigned i;
 170         int l;
 171         (void) data;
 172
 173         /* construct initial register assignment */
 174         n_classes = arch_env_get_n_reg_class(arch_env);
 175         for(i = 0; i < n_classes; ++i) {
 176                 const arch_register_class_t *cls    = arch_env_get_reg_class(arch_env, i);
 177                 unsigned                     n_regs = arch_register_class_n_regs(cls);
 178                 memset(register_values[i], 0, sizeof(ir_node*) * n_regs);
 179         }
 180
 181         assert(lv->nodes && "live sets must be computed");
 182         DBG((dbg, LEVEL_1, "\nProcessing block %+F (from end)\n", block));
 183         be_lv_foreach(lv, block, be_lv_state_end, l) {
 184                 ir_node *node = be_lv_get_irn(lv, block, l);
 185                 set_reg_value(node);
 186         }
 187         DBG((dbg, LEVEL_1, "\nstart processing\n"));
 188
 189         /* walk the block from last insn to the first */
 190         current_node = sched_last(block);
 191         for( ; !sched_is_begin(current_node);
 192                         current_node = sched_prev(current_node)) {
 193                 ir_op             *op;
 194                 ir_node           *last;
 195                 peephole_opt_func  func;
 196
 197                 if(is_Phi(current_node))
 198                         break;
 199
 200                 clear_defs(current_node);
 201                 set_uses(current_node);
 202
 203                 op   = get_irn_op(current_node);
 204                 func = (peephole_opt_func) op->ops.generic;
 205                 if(func == NULL)
 206                         continue;
 207
 208                 last = current_node;
 209                 func(current_node);
 210                 /* was the current node replaced? */
 211                 if(current_node != last) {
 212                         set_uses(current_node);
 213                 }
 214         }
 215 }
 216
 217 /**
 218  * Walk through the block schedule and skip all barrier nodes.
 219  */
 220 static void skip_barrier(ir_node *ret_blk, ir_graph *irg) {
 221         ir_node *irn;
 222
 223         sched_foreach_reverse(ret_blk, irn) {
 224                 if (be_is_Barrier(irn)) {
 225                         const ir_edge_t *edge, *next;
 226
 227                         foreach_out_edge_safe(irn, edge, next) {
 228                                 ir_node *proj = get_edge_src_irn(edge);
 229                                 int      pn   = (int)get_Proj_proj(proj);
 230                                 ir_node *pred = get_irn_n(irn, pn);
 231
 232                                 edges_reroute_kind(proj, pred, EDGE_KIND_NORMAL, irg);
 233                                 edges_reroute_kind(proj, pred, EDGE_KIND_DEP, irg);
 234                         }
 235                         sched_remove(irn);
 236                         kill_node(irn);
 237                         break;
 238                 }
 239         }
 240 }
 241
 242 /**
 243  * Kill the Barrier nodes for better peephole optimization.
 244  */
 245 static void     kill_barriers(ir_graph *irg) {
 246         ir_node *end_blk = get_irg_end_block(irg);
 247         ir_node *start_blk;
 248         int i;
 249
 250         /* skip the barrier on all return blocks */
 251         for (i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
 252                 ir_node *be_ret = get_Block_cfgpred(end_blk, i);
 253                 ir_node *ret_blk = get_nodes_block(be_ret);
 254
 255                 skip_barrier(ret_blk, irg);
 256         }
 257
 258         /* skip the barrier on the start block */
 259         start_blk = get_irg_start_block(irg);
 260         skip_barrier(start_blk, irg);
 261 }
 262
 263
 264 void be_peephole_opt(be_irg_t *birg)
 265 {
 266         ir_graph   *irg = be_get_birg_irg(birg);
 267         unsigned n_classes;
 268         unsigned i;
 269
 270         /* barrier nodes are used for register allocations. They hinders
 271          * peephole optimizations, so remove them here. */
 272         kill_barriers(irg);
 273
 274         /* we sometimes find BadE nodes in float apps like optest_float.c or
 275          * kahansum.c for example... */
 276         be_liveness_invalidate(birg->lv);
 277         be_liveness_assure_sets(be_assure_liveness(birg));
 278
 279         arch_env = be_get_birg_arch_env(birg);
 280         lv       = be_get_birg_liveness(birg);
 281
 282         n_classes = arch_env_get_n_reg_class(arch_env);
 283         register_values = alloca(sizeof(register_values[0]) * n_classes);
 284         for(i = 0; i < n_classes; ++i) {
 285                 const arch_register_class_t *cls    = arch_env_get_reg_class(arch_env, i);
 286                 unsigned                     n_regs = arch_register_class_n_regs(cls);
 287                 register_values[i] = alloca(sizeof(ir_node*) * n_regs);
 288         }
 289
 290         irg_block_walk_graph(irg, process_block, NULL, NULL);
 291 }
 292
 293 void be_peephole_init(void)
 294 {
 295         clear_irp_opcodes_generic_func();
 296 }
 297
 298 void be_init_peephole(void)
 299 {
 300         FIRM_DBG_REGISTER(dbg, "firm.be.peephole");
 301 }
 302
 303 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillbelady);