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#include "lisc.h"
/* liveness analysis
* requires rpo computation
*/
void
filllive(Fn *f)
{
Blk *b;
Ins *i;
Phi *p;
int z, n, chg;
Bits *kill, *use, *k, *u, bt;
assert(f->ntmp <= NBit*BITS);
kill = alloc(f->ntmp * sizeof kill[0]);
use = alloc(f->ntmp * sizeof use[0]);
for (b=f->start; b; b=b->link) {
k = &kill[b->id];
u = &use[b->id];
for (p=b->phi; p; p=p->link)
BSET(*k, p->to.val);
for (i=b->ins; i-b->ins < b->nins; i++) {
if (!req(i->to, R))
BSET(*k, i->to.val);
if (!req(i->arg[0], R))
BSET(*u, i->arg[0].val);
if (!req(i->arg[1], R))
BSET(*u, i->arg[1].val);
}
if (!req(b->jmp.arg, R))
BSET(*u, b->jmp.arg.val);
for (z=0; z<BITS; z++)
u->t[z] &= ~k->t[z];
memset(&b->in, 0, sizeof(Bits));
memset(&b->out, 0, sizeof(Bits));
}
Again:
chg = 0;
for (n=f->nblk-1; n>=0; n--) {
b = f->rpo[n];
bt = b->out;
if (b->s1)
for (z=0; z<BITS; z++)
b->out.t[z] |= b->s1->in.t[z];
if (b->s2)
for (z=0; z<BITS; z++)
b->out.t[z] |= b->s2->in.t[z];
chg |= memcmp(&b->out, &bt, sizeof(Bits)) != 0;
k = &kill[n];
u = &use[n];
for (z=0; z<BITS; z++)
b->in.t[z] = (b->out.t[z]|u->t[z]) & ~k->t[z];
}
if (chg)
goto Again;
free(kill);
free(use);
}
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