/* ULOAD forwarding. */
TRef LJ_FASTCALL lj_opt_fwd_uload(jit_State *J)
{
IRRef uref = fins->op1;
IRRef lim = REF_BASE; /* Search limit. */
IRIns *xr = IR(uref);
IRRef ref;
/* Search for conflicting stores. */
ref = J->chain[IR_USTORE];
while (ref > lim) {
IRIns *store = IR(ref);
switch (aa_uref(xr, IR(store->op1))) {
case ALIAS_NO: break; /* Continue searching. */
case ALIAS_MAY: lim = ref; goto cselim; /* Limit search for load. */
case ALIAS_MUST: return store->op2; /* Store forwarding. */
}
ref = store->prev;
}
cselim:
/* Try to find a matching load. Below the conflicting store, if any. */
ref = J->chain[IR_ULOAD];
while (ref > lim) {
IRIns *ir = IR(ref);
if (ir->op1 == uref ||
(IR(ir->op1)->op12 == IR(uref)->op12 && IR(ir->op1)->o == IR(uref)->o))
return ref; /* Match for identical or equal UREFx (non-CSEable UREFO). */
ref = ir->prev;
}
return lj_ir_emit(J);
}
/* This is rather simplistic right now, but better than nothing. */
TRef LJ_FASTCALL lj_opt_fwd_tab_len(jit_State *J)
{
IRRef tab = fins->op1; /* Table reference. */
IRRef lim = tab; /* Search limit. */
IRRef ref;
/* Any ASTORE is a conflict and limits the search. */
if (J->chain[IR_ASTORE] > lim) lim = J->chain[IR_ASTORE];
/* Search for conflicting HSTORE with numeric key. */
ref = J->chain[IR_HSTORE];
while (ref > lim) {
IRIns *store = IR(ref);
IRIns *href = IR(store->op1);
IRIns *key = IR(href->op2);
if (irt_isnum(key->o == IR_KSLOT ? IR(key->op1)->t : key->t)) {
lim = ref; /* Conflicting store found, limits search for TLEN. */
break;
}
ref = store->prev;
}
/* Search for aliasing table.clear. */
if (!fwd_aa_tab_clear(J, lim, tab))
return lj_ir_emit(J);
/* Try to find a matching load. Below the conflicting store, if any. */
return lj_opt_cselim(J, lim);
}
