nsz Git - libfirm/blob - ir/be/beconstrperm.c

   1 /**
   2  * Author:      Daniel Grund
   3  * Date:                15.12.2005
   4  * Copyright:   (c) Universitaet Karlsruhe
   5  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
   6  *
   7  */
   8 #ifdef HAVE_CONFIG_H
   9 #include "config.h"
  10 #endif
  11
  12 #include "irgraph_t.h"
  13 #include "irnode_t.h"
  14 #include "irgwalk.h"
  15
  16 #include "bearch.h"
  17 #include "belive_t.h"
  18 #include "benode_t.h"
  19 #include "besched_t.h"
  20 #include "beconstrperm.h"
  21
  22 static void walker_insert_constr_perms(ir_node *bl, void *env) {
  23         ir_node *irn;
  24         be_chordal_env_t *cenv = env;
  25         const be_main_env_t *menv = cenv->main_env;
  26         const arch_env_t *aenv = menv->arch_env;
  27         arch_register_req_t req;
  28         int pos, max;
  29
  30         sched_foreach(bl, irn) {
  31                 ir_node *perm = NULL;
  32
  33                 /* check for a restriction of the result (-1) or one of the operands (0..n) */
  34                 max = get_irn_arity(irn);
  35                 for(pos=-1; pos<max; ++pos) {
  36                         arch_get_register_req(aenv, &req, irn, pos);
  37                         /* if a restriction is found, insert a perm before the irn */
  38                         if (cenv->cls == arch_get_irn_reg_class(aenv, irn, pos) && req.type == arch_register_req_type_limited) {
  39
  40                                 if(!perm)
  41                                         perm = insert_Perm_after(menv, cenv->cls, cenv->dom_front, sched_prev(irn));
  42
  43                                 /*
  44                                  * Turn an input constraint into an output constraint:
  45                                  * The Proj of the Perm which corresponds to the input
  46                                  * constraint will have the input constraint of the node
  47                                  * as an output constraint
  48                                  */
  49                                 if(pos >= 0) {
  50                                         ir_node *op = get_irn_n(irn, pos);
  51
  52                                         /*
  53                                          * The operand must be a proj now, since a perm cut
  54                                          * all live ranges.
  55                                          */
  56                                         assert(is_Proj(op));
  57                                         be_set_Perm_out_req(perm, get_Proj_proj(op), &req);
  58                                 }
  59                         }
  60                 }
  61
  62                 /*
  63                  * If we inserted a perm,
  64                  * we have to recompute liveness analysis since inserting
  65                  * a Perm changes the liveness situation at the end
  66                  * of the block.
  67                  * (its needed by successive calls to insert_Perm_after)
  68                  * Perhaps thinking about an online liveness analysis
  69                  * would help.
  70                  */
  71                 if(perm)
  72                         be_liveness(get_irn_irg(bl));
  73         }
  74 }
  75
  76 void be_insert_constr_perms(be_chordal_env_t *cenv) {
  77         irg_block_walk_graph(cenv->irg, walker_insert_constr_perms, NULL, cenv);
  78 }