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