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#include "ir.h"
static int
ins(struct function *fn, struct instr *ins, struct block *blk, int *curi)
{
int narg = opnarg[ins->op];
if ((oisarith(ins->op) || oiscmp(ins->op)) && isnumcon(ins->l) && (narg == 1 || isnumcon(ins->r))) {
bool ok;
if (narg == 1) ok = foldunop(&ins->l, ins->op, ins->cls, ins->l);
else ok = foldbinop(&ins->l, ins->op, ins->cls, ins->l, ins->r);
if (!ok) return 0; /* could be div/0 */
ins->op = Ocopy;
ins->cls = insrescls(*ins);
ins->r = NOREF;
return 1;
}
return 0;
}
static void
jmpfind(struct block **final, struct block **pblk)
{
struct block **p2 = &final[(*pblk)->id];
if (*p2 && !(*p2)->phi.n) {
jmpfind(final, p2);
*pblk = *p2;
}
}
static void
fillpredsrec(struct block *blk)
{
while (blk && !wasvisited(blk)) {
markvisited(blk);
if (!blk->s1) return;
if (!blk->s1->phi.n) addpred(blk->s1, blk);
if (!blk->s2) {
blk = blk->s1;
continue;
}
if (!blk->s2->phi.n) addpred(blk->s2, blk);
fillpredsrec(blk->s1);
blk = blk->s2;
}
}
static void
fillpreds(struct function *fn)
{
struct block *blk = fn->entry, *next;
do {
if (blk->phi.n) continue;
if (blk->npred > 1)
xbfree(blk->_pred);
blk->npred = 0;
blk->_pred = NULL;
} while ((blk = blk->lnext) != fn->entry);
startbbvisit();
fillpredsrec(fn->entry);
blk = fn->entry->lnext;
do { /* remove dead blocks */
next = blk->lnext;
if (!blk->npred) freeblk(fn, blk);
} while ((blk = next) != fn->entry);
}
void
simpl(struct function *fn)
{
FREQUIRE(FNUSE);
int inschange = 0,
blkchange = 0;
struct block **jmpfinal = allocz(fn->passarena, fn->nblk * sizeof *jmpfinal, 0);
struct block *blk = fn->entry;
do {
for (int i = 0; i < blk->phi.n; ++i) {
}
for (int i = 0; i < blk->ins.n; ++i) {
inschange += ins(fn, &instrtab[blk->ins.p[i]], blk, &i);
}
/* merge blocks:
* @blk:
* ... (1)
* b @s
* @s:
* ... (2)
* b {...}
*=>
* @blk:
* ... (1)
* ... (2)
* b {...}
* */
if (blk != fn->entry) while (blk->s1 && !blk->s2 && blk->s1->npred == 1 && !blk->phi.n) {
struct block *s = blk->s1;
vpushn(&blk->ins, s->ins.p, s->ins.n);
blk->jmp = blk->s1->jmp;
for (int i = 0; i < 2; ++i) {
struct block *ss = (&s->s1)[i];
if (ss) for (int j = 0; j < ss->npred; ++j) {
if (blkpred(ss, j) == s) {
blkpred(ss, j) = blk;
break;
}
}
}
/* breaks use for temps used in s */
if (s->ins.n || s->jmp.arg[0].t == RTMP || s->jmp.arg[1].t == RTMP)
fn->prop &= ~FNUSE;
blk->s1 = s->s1;
blk->s2 = s->s2;
freeblk(fn, s);
}
/* thread jumps.. */
if (!blk->phi.n && !blk->ins.n) {
if (blk->jmp.t == Jb && !blk->s2) {
jmpfind(jmpfinal, &blk->s1);
if (blk->s1 != blk) {
++blkchange;
jmpfinal[blk->id] = blk->s1;
}
}
}
} while ((blk = blk->lnext) != fn->entry);
if (inschange) {
if (!(fn->prop & FNUSE)) filluses(fn);
copyopt(fn);
}
if (blkchange) {
do {
if (blk->s1) jmpfind(jmpfinal, &blk->s1);
if (blk->s2) jmpfind(jmpfinal, &blk->s2);
if (blk->s1 && blk->s1 == blk->s2) {
memset(blk->jmp.arg, 0, sizeof blk->jmp.arg);
blk->s2 = NULL;
}
} while ((blk = blk->lnext) != fn->entry);
fillpreds(fn);
}
}
/* vim:set ts=3 sw=3 expandtab: */
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