diff options
Diffstat (limited to 'lisc/live.c')
| -rw-r--r-- | lisc/live.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/lisc/live.c b/lisc/live.c new file mode 100644 index 0000000..82acae9 --- /dev/null +++ b/lisc/live.c @@ -0,0 +1,59 @@ +#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); +} |