ack/mach/proto/ncg/equiv.c
ceriel 3ecaa0b634 some fixes: fix order in which registers are allocated, make sure that
a pattern chosen by the distance routine can be made from the stack if the
fakestack does not contain enough tokens
1989-03-17 16:49:58 +00:00

95 lines
1.8 KiB
C

#ifndef NORCSID
static char rcsid[] = "$Header$";
#endif
#include "assert.h"
#include "equiv.h"
#include "param.h"
#include "tables.h"
#include "types.h"
#include <cgg_cg.h>
#include "data.h"
#include "result.h"
#include "extern.h"
/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*
* Author: Hans van Staveren
*/
extern string myalloc();
int rar[MAXCREG];
rl_p *lar;
int maxindex;
int regclass[NREGS];
struct perm *perms;
struct perm *
tuples(regls,nregneeded) rl_p *regls; {
int class=0;
register i,j;
/*
* First compute equivalence classes of registers.
*/
for (i=NREGS;--i>=0;) {
regclass[i] = class++;
if (getrefcount(i, FALSE) == 0) {
for (j=NREGS;--j>i;) {
if (eqregclass(i,j) &&
eqtoken(&machregs[i].r_contents,
&machregs[j].r_contents)) {
regclass[i] = regclass[j];
break;
}
}
}
}
/*
* Now create tuples through a recursive function
*/
maxindex = nregneeded;
lar = regls;
perms = 0;
permute(0);
return(perms);
}
permute(index) {
register struct perm *pp;
register rl_p rlp;
register i,j;
if (index == maxindex) {
for (pp=perms; pp != 0; pp=pp->p_next) {
for (i=0; i<maxindex; i++)
if (regclass[rar[i]] != regclass[pp->p_rar[i]])
goto diff;
for (i=0; i<maxindex; i++)
for (j=0; j<i; j++)
if (clash(rar[i],rar[j]) !=
clash(pp->p_rar[i],pp->p_rar[j]))
goto diff;
return;
diff: ;
}
pp = (struct perm *) myalloc(sizeof ( *pp ));
pp->p_next = perms;
for (i=0; i<maxindex; i++)
pp->p_rar[i] = rar[i];
perms = pp;
} else {
rlp=lar[index];
for (i=rlp->rl_n; i>0; i--) {
rar[index] = rlp->rl_list[rlp->rl_n-i];
permute(index+1);
}
}
}