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Improve AA for field accesses: disambiguate new allocations.

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Mike Pall 2010-09-21 15:21:26 +02:00
parent 3ae27ffebe
commit 4cd2299acd
1 changed files with 6 additions and 3 deletions
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9
src/lj_opt_mem.c
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@ -43,6 +43,7 @@ static AliasRet aa_table(jit_State *J, IRRef ta, IRRef tb)
IRIns *ir, *taba = IR(ta), *tabb = IR(tb);
int newa, newb;
lua_assert(ta != tb);
lua_assert(irt_istab(taba->t) && irt_istab(tabb->t));
/* Disambiguate new allocations. */
newa = (taba->o == IR_TNEW || taba->o == IR_TDUP);
newb = (tabb->o == IR_TNEW || tabb->o == IR_TDUP);
@ -435,12 +436,14 @@ doemit:
** Field loads are cheap and field stores are rare.
** Simple disambiguation based on field types is good enough.
*/
static AliasRet aa_fref(IRIns *refa, IRIns *refb)
static AliasRet aa_fref(jit_State *J, IRIns *refa, IRIns *refb)
{
if (refa->op2 != refb->op2)
return ALIAS_NO; /* Different fields. */
if (refa->op1 == refb->op1)
return ALIAS_MUST; /* Same field, same object. */
else if (refa->op2 >= IRFL_TAB_META && refa->op2 <= IRFL_TAB_NOMM)
return aa_table(J, refa->op1, refb->op1); /* Disambiguate tables. */
else
return ALIAS_MAY; /* Same field, possibly different object. */
}
@ -457,7 +460,7 @@ TRef LJ_FASTCALL lj_opt_fwd_fload(jit_State *J)
ref = J->chain[IR_FSTORE];
while (ref > oref) {
IRIns *store = IR(ref);
switch (aa_fref(fins, IR(store->op1))) {
switch (aa_fref(J, fins, 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. */
@ -487,7 +490,7 @@ TRef LJ_FASTCALL lj_opt_dse_fstore(jit_State *J)
IRRef ref = *refp;
while (ref > fref) { /* Search for redundant or conflicting stores. */
IRIns *store = IR(ref);
switch (aa_fref(xr, IR(store->op1))) {
switch (aa_fref(J, xr, IR(store->op1))) {
case ALIAS_NO:
break; /* Continue searching. */
case ALIAS_MAY: