/* Peephole optimization routines and tables
Copyright (C) 2001,2002 Free Software Foundation, Inc.
This file is part of Gforth.
Gforth is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*/
#include "config.h"
#include "forth.h"
#include <stdlib.h>
#include <string.h>
#include <assert.h>
/* the numbers in this struct are primitive indices */
typedef struct Combination {
int prefix;
int lastprim;
int combination_prim;
} Combination;
Combination peephole_table[] = {
#include "peephole.i"
};
#ifdef PRINT_SUPER_LENGTHS
char *prim_names[] = {
#include "prim_names.i"
};
Combination *find_super(Cell prim)
{
Cell i;
for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
if (peephole_table[i].combination_prim == prim)
return &peephole_table[i];
}
return NULL;
}
Cell sum_length(Cell prim)
{
Combination *super=find_super(prim);
if (super)
return sum_length(super->prefix)+prim_length(super->lastprim);
else
return prim_length(prim);
}
void print_prim(Cell prim)
{
fprintf(stderr, "%s", prim_names[prim]);
}
void print_super(Cell prim)
{
Combination *super=find_super(prim);
if (super) {
print_super(super->prefix);
fprintf(stderr, " ");
print_prim(super->lastprim);
} else {
print_prim(prim);
}
}
void print_super_lengths()
{
Cell i;
for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
Cell super_length = prim_length(peephole_table[i].combination_prim);
Cell sum_super_length = sum_length(peephole_table[i].combination_prim);
fprintf(stderr, "%6.4f %3d %3d ", ((double)super_length)/sum_super_length,
super_length, sum_super_length);
print_super(peephole_table[i].combination_prim);
fprintf(stderr,"\n");
}
}
#endif
int use_super = 1;
typedef Xt Inst;
typedef struct Peeptable_entry {
struct Peeptable_entry *next;
Inst prefix;
Inst lastprim;
Inst combination_prim;
} Peeptable_entry;
#define HASH_SIZE 1024
#define hash(_i1,_i2) (((((Cell)(_i1))^((Cell)(_i2)))>>4)&(HASH_SIZE-1))
Cell peeptable;
Cell prepare_peephole_table(Inst insts[])
{
Cell i;
Peeptable_entry **pt = (Peeptable_entry **)calloc(HASH_SIZE,sizeof(Peeptable_entry *));
for (i=0; i<sizeof(peephole_table)/sizeof(peephole_table[0]); i++) {
Combination *c = &peephole_table[i];
Peeptable_entry *p = (Peeptable_entry *)malloc(sizeof(Peeptable_entry));
Cell h;
p->prefix = insts[c->prefix];
p->lastprim = insts[c->lastprim];
p->combination_prim = insts[c->combination_prim];
h = hash(p->prefix,p->lastprim);
p->next = pt[h];
pt[h] = p;
}
return (Cell)pt;
}
Inst peephole_opt(Inst inst1, Inst inst2, Cell peeptable)
{
Peeptable_entry **pt = (Peeptable_entry **)peeptable;
Peeptable_entry *p;
if (use_super == 0)
return 0;
for (p = pt[hash(inst1,inst2)]; p != NULL; p = p->next)
if (inst1 == p->prefix && inst2 == p->lastprim)
return p->combination_prim;
return NULL;
}
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