diff options
Diffstat (limited to 'loopopt.c')
| -rw-r--r-- | loopopt.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/loopopt.c b/loopopt.c new file mode 100644 index 0000000..0592be4 --- /dev/null +++ b/loopopt.c @@ -0,0 +1,236 @@ +#include "all.h" + +static int +forloop(Blk *bh, Blk *bb) +{ + if (bh->npred == 2) + if (bh->jmp.type == Jjnz) + if (bb->npred == 1) + if (bb->jmp.type == Jjmp) + if (bb->jmp.s[0].b == bh) + return 1; + return 0; +} + +static int +doloop(Blk *bh) +{ + if (bh->npred == 2) + if (bh->jmp.type == Jjnz) + if (bh->jmp.s[0].b == bh || bh->jmp.s[1].b == bh) + return 1; + return 0; +} + +static int +loopvar(Fn *fn, Blk *bh, Blk *bb, uint np, Ref *prl, Ref *pr0, Ref *pri) +{ + Blk *bp; + Phi *p; + Suc *sb, *sp; + Tmp *t; + Ins *i; + + assert(bh->npred == 2); + assert(bh->pred[0] == bb || bh->pred[1] == bb); + bp = bh->pred[bh->pred[0] == bb]; /* pre-header */ + assert(np < bh->nphi); + p = &bh->phi[np]; + if (KBASE(p->cls) != 0) + return 0; /* not integer */ + sp = getsuc(bp, bh); + assert(sp->nr == bh->nphi); + *pr0 = sp->r[np]; + sb = getsuc(bb, bh); + assert(sb->nr == bh->nphi); + *prl = sb->r[np]; + if (rtype(*prl) != RTmp) + return 0; /* loop var must be an incremented tmp */ + t = &fn->tmp[prl->val]; + if (t->bid != bb->id || t->def == 0) + return 0; /* loop var must be defined by an add ins in the body */ + i = t->def; + if (i->op != Oadd || req(i->arg[0], p->to) == req(i->arg[1], p->to)) + return 0; + *pri = i->arg[req(i->arg[0], p->to)]; + assert(p->cls == i->cls); + if (rtype(*pri) == RTmp) { + t = &fn->tmp[pri->val]; + if (t->bid == bh->id || t->bid == bb->id) + return 0; + return 1; + } + else { + assert(rtype(*pri) == RCon); + return 1; + } + return 0; +} + +static void +mulredux(Fn *fn, Blk *bh, Blk *bb, Blk *bp, uint np, Ref rl, Ref r0, Ref ri, Ins **pvins, uint *pnins) +{ + Ins *i; + Tmp *t; + Ref r1, rlop; + Phi *p; + Suc *sb, *sp; + + /* dead simple case for now... majority case in practice */ + if (!req(r0, con01[0]) || !req(ri, con01[1])) + return; + + assert(!req(rl, R)); /* rl unused */ + assert(np < bh->nphi); + p = &bh->phi[np]; + for (i = bb->ins; i < &bb->ins[bb->nins]; i++) { + /* TODO i->cls != p->cls is not necessary? */ + if (i->op != Omul || i->cls != p->cls + || req(i->arg[0], p->to) == req(i->arg[1], p->to)) + continue; + r1 = i->arg[req(i->arg[0], p->to)]; + if (rtype(r1) == RTmp) { + t = &fn->tmp[r1.val]; + if (t->bid == bh->id || t->bid == bb->id) + continue; + } else + assert(rtype(r1) == RCon); + assert(KBASE(i->cls) == 0); + + rlop = newtmp("lop", i->cls, fn); + vgrow(&bh->phi, ++bh->nphi); + bh->phi[bh->nphi-1] = (Phi){.to = i->to, .cls = i->cls}; + sp = getsuc(bp, bh); + vgrow(&sp->r, ++sp->nr); + sp->r[sp->nr-1] = con01[0]; + assert(sp->nr == bh->nphi); + sb = getsuc(bb, bh); + vgrow(&sb->r, ++sb->nr); + sb->r[sp->nr-1] = rlop; + assert(sb->nr == bh->nphi); + addins(pvins, pnins, &(Ins){.to = rlop, .op = Oadd, .cls = i->cls, + .arg = {i->to, r1}}); + *i = (Ins){.op = Onop}; + } +} + +static void +addbase(Fn *fn, Blk *bh, Blk *bb, Blk *bp, uint np, Ref rl, Ref r0, Ref ri, Ins **pvins, uint *pnins) +{ + Ins *i, *ii, *ib; + Tmp *t, *ti, *tb; + Use *u; + Ref rb; + Phi *p; + Suc *sp; + + /* dead simple case for now... majority case in practice */ + if (!req(r0, con01[0])) + return; + + assert(!req(ri, R)); /* unused */ + assert(pvins && pnins); /* unused */ + assert(np < bh->nphi); + p = &bh->phi[np]; + assert(rtype(p->to) == RTmp); + t = &fn->tmp[p->to.val]; + if (t->nuse != 2) + return; + + i = ib = 0; + for (u = t->use; u < &t->use[t->nuse]; u++) { + if (u->type != UIns) + return; + i = u->u.ins; + if (i->op != Oadd || i->cls != p->cls || u->bid != bb->id) + return; + assert(req(i->arg[0], p->to) || req(i->arg[1], p->to)); + if (req(i->to, rl)) { + assert(rtype(i->to) == RTmp); + ti = &fn->tmp[i->to.val]; + if (ti->nuse != 1) + return; + assert(ti->use[0].type == UPhi); + assert(ti->use[0].bid == bh->id); + assert(ti->use[0].u.p.np == np); + assert(ti->use[0].u.p.pbid == bb->id); + ii = i; + continue; + } + rb = i->arg[req(i->arg[0], p->to)]; + if (req(rb, p->to)) + return; + if (rtype(rb) == RTmp) { + tb = &fn->tmp[rb.val]; + if (tb->bid == bh->id || tb->bid == bb->id) + return; + } else + assert(rtype(rb) == RCon); + ib = i; + } + assert(ii); + assert(ib); + sp = getsuc(bp, bh); + assert(sp->nr == bh->nphi); + assert(req(sp->r[np], con01[0])); + sp->r[np] = rb; + assert(req(ii->arg[0], p->to) != req(ii->arg[1], p->to)); + ii->arg[!req(ii->arg[0], p->to)] = ib->to; + p->to = ib->to; + *ib = (Ins){.op = Onop}; +} + +typedef void optfn_t(Fn *, Blk *, Blk *, Blk *, uint, Ref, Ref, Ref, Ins **, uint *); + +static void +loopvaropt(Fn *fn, optfn_t *optfn) +{ + uint bid; + Blk *bh, *bb, *bp; /* header, body, pre-header */ + Phi *p; + Ins *vins; + uint nins, np; + Ref rl, r0, ri; /* loop var, loop var init, loop var inc */ + + nins = 0; + vins = vnew(nins, sizeof vins[0], PFn); /* TODO use insb */ + + for (bid = 0; bid < fn->nblk; bid++) { + bh = fn->rpo[bid]; + if (forloop(bh, bh->jmp.s[0].b)) + bb = bh->jmp.s[0].b; + else if (forloop(bh, bh->jmp.s[1].b)) + bb = bh->jmp.s[1].b; + else if (doloop(bh)) + bb = bh; /* header and body */ + else + continue; + bp = bh->pred[bh->pred[0] == bh]; + assert(bh->loop > 1); + assert(bh->loop == bb->loop); + nins = 0; + for (np = 0; np < bh->nphi; np++) + if (loopvar(fn, bh, bb, np, &rl, &r0, &ri)) { + p = &bh->phi[np]; + assert(KBASE(p->cls) == 0); + optfn(fn, bh, bb, bp, np, rl, r0, ri, &vins, &nins); + } + addnins(&bb->ins, &bb->nins, vins, nins); + } +} + +void +loopopt(Fn *fn) +{ + /* encourage simple loops */ + ifelim(fn); + fillcfg(fn); + blkmerge(fn); + fillcfg(fn); + filluse(fn); + fillloop(fn); + + loopvaropt(fn, mulredux); + filluse(fn); + loopvaropt(fn, addbase); +} |