mach/proto/cg/equiv.c

   1 #ifndef NORCSID
   2 static char rcsid[] = "$Id: equiv.c,v 2.4 1994/06/24 13:23:29 ceriel Exp $";
   3 #endif
   4
   5 #include "assert.h"
   6 #include "equiv.h"
   7 #include "param.h"
   8 #include "tables.h"
   9 #include "types.h"
  10 #include <cg_pattern.h>
  11 #include "data.h"
  12 #include "result.h"
  13 #include "extern.h"
  14
  15 /*
  16  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  17  * See the copyright notice in the ACK home directory, in the file "Copyright".
  18  *
  19  * Author: Hans van Staveren
  20  */
  21
  22 extern string myalloc();
  23
  24 int rar[MAXCREG];
  25 rl_p *lar;
  26 int maxindex;
  27 int regclass[NREGS];
  28 struct perm *perms;
  29
  30 struct perm *
  31 tuples(regls,nregneeded) rl_p *regls; {
  32         int class=0;
  33         register i,j;
  34
  35         /*
  36          * First compute equivalence classes of registers.
  37          */
  38
  39         for (i=0;i<NREGS;i++) {
  40                 regclass[i] = class++;
  41                 if (getrefcount(i, FALSE) == 0) {
  42                         for (j=0;j<i;j++) {
  43                                 if (eqregclass(i,j) &&
  44                                     eqtoken(&machregs[i].r_contents,
  45                                             &machregs[j].r_contents)) {
  46                                         regclass[i] = regclass[j];
  47                                         break;
  48                                 }
  49                         }
  50                 }
  51         }
  52
  53         /*
  54          * Now create tuples through a recursive function
  55          */
  56
  57         maxindex = nregneeded;
  58         lar = regls;
  59         perms = 0;
  60         permute(0);
  61         return(perms);
  62 }
  63
  64 permute(index) {
  65         register struct perm *pp;
  66         register rl_p rlp;
  67         register i,j;
  68
  69         if (index == maxindex) {
  70                 for (pp=perms; pp != 0; pp=pp->p_next) {
  71                         for (i=0; i<maxindex; i++)
  72                                 if (regclass[rar[i]] != regclass[pp->p_rar[i]])
  73                                         goto diff;
  74                         for (i=0; i<maxindex; i++)
  75                                 for (j=0; j<i; j++)
  76                                         if (clash(rar[i],rar[j]) !=
  77                                             clash(pp->p_rar[i],pp->p_rar[j]))
  78                                                 goto diff;
  79                         return;
  80                     diff: ;
  81                 }
  82                 pp = (struct perm *) myalloc(sizeof ( *pp ));
  83                 pp->p_next = perms;
  84                 for (i=0; i<maxindex; i++)
  85                         pp->p_rar[i] = rar[i];
  86                 perms = pp;
  87         } else {
  88                 rlp=lar[index];
  89                 for (i=rlp->rl_n-1; i>=0; i--) {
  90                         rar[index] = rlp->rl_list[i];
  91                         permute(index+1);
  92                 }
  93         }
  94 }