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Improve FOLD/CSE of field loads and array/hash refs across NEWREF.

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This commit is contained in:
Mike Pall 2010-09-21 02:28:14 +02:00
parent 23b5c56d41
commit 38628d93b8
3 changed files with 23 additions and 15 deletions
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1
src/lj_iropt.h
View File

@ -111,6 +111,7 @@ LJ_FUNC TRef LJ_FASTCALL lj_opt_fwd_uload(jit_State *J);
LJ_FUNC TRef LJ_FASTCALL lj_opt_fwd_fload(jit_State *J);
LJ_FUNC TRef LJ_FASTCALL lj_opt_fwd_tab_len(jit_State *J);
LJ_FUNC int LJ_FASTCALL lj_opt_fwd_href_nokey(jit_State *J);
LJ_FUNC int LJ_FASTCALL lj_opt_fwd_tptr(jit_State *J, IRRef lim);
LJ_FUNC int lj_opt_fwd_wasnonnil(jit_State *J, IROpT loadop, IRRef xref);
/* Dead-store elimination. */

23
src/lj_opt_fold.c
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@ -1233,23 +1233,15 @@ LJFOLDF(fwd_href_tdup)
}
/* We can safely FOLD/CSE array/hash refs and field loads, since there
** are no corresponding stores. But NEWREF may invalidate all of them.
** Lacking better disambiguation for table references, these optimizations
** are simply disabled across any NEWREF.
** are no corresponding stores. But we need to check for any NEWREF with
** an aliased table, as it may invalidate all of the pointers and fields.
** Only HREF needs the NEWREF check -- AREF and HREFK already depend on
** FLOADs. And NEWREF itself is treated like a store (see below).
*/
LJFOLD(HREF any any)
LJFOLDF(cse_href)
{
TRef tr = lj_opt_cse(J);
return tref_ref(tr) < J->chain[IR_NEWREF] ? EMITFOLD : tr;
}
LJFOLD(FLOAD TNEW IRFL_TAB_ASIZE)
LJFOLDF(fload_tab_tnew_asize)
{
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fins->op1 > J->chain[IR_NEWREF])
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && lj_opt_fwd_tptr(J, fins->op1))
return INTFOLD(fleft->op1);
return NEXTFOLD;
}
@ -1257,7 +1249,7 @@ LJFOLDF(fload_tab_tnew_asize)
LJFOLD(FLOAD TNEW IRFL_TAB_HMASK)
LJFOLDF(fload_tab_tnew_hmask)
{
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fins->op1 > J->chain[IR_NEWREF])
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && lj_opt_fwd_tptr(J, fins->op1))
return INTFOLD((1 << fleft->op2)-1);
return NEXTFOLD;
}
@ -1265,7 +1257,7 @@ LJFOLDF(fload_tab_tnew_hmask)
LJFOLD(FLOAD TDUP IRFL_TAB_ASIZE)
LJFOLDF(fload_tab_tdup_asize)
{
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fins->op1 > J->chain[IR_NEWREF])
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && lj_opt_fwd_tptr(J, fins->op1))
return INTFOLD((int32_t)ir_ktab(IR(fleft->op1))->asize);
return NEXTFOLD;
}
@ -1273,11 +1265,12 @@ LJFOLDF(fload_tab_tdup_asize)
LJFOLD(FLOAD TDUP IRFL_TAB_HMASK)
LJFOLDF(fload_tab_tdup_hmask)
{
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fins->op1 > J->chain[IR_NEWREF])
if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && lj_opt_fwd_tptr(J, fins->op1))
return INTFOLD((int32_t)ir_ktab(IR(fleft->op1))->hmask);
return NEXTFOLD;
}
LJFOLD(HREF any any)
LJFOLD(FLOAD any IRFL_TAB_ARRAY)
LJFOLD(FLOAD any IRFL_TAB_NODE)
LJFOLD(FLOAD any IRFL_TAB_ASIZE)
@ -1285,7 +1278,7 @@ LJFOLD(FLOAD any IRFL_TAB_HMASK)
LJFOLDF(fload_tab_ah)
{
TRef tr = lj_opt_cse(J);
return tref_ref(tr) < J->chain[IR_NEWREF] ? EMITFOLD : tr;
return lj_opt_fwd_tptr(J, tref_ref(tr)) ? tr : EMITFOLD;
}
/* Strings are immutable, so we can safely FOLD/CSE the related FLOAD. */

14
src/lj_opt_mem.c
View File

@ -277,6 +277,20 @@ int LJ_FASTCALL lj_opt_fwd_href_nokey(jit_State *J)
return 1; /* No conflict. Can fold to niltv. */
}
/* Check whether there's no aliasing NEWREF for the left operand. */
int LJ_FASTCALL lj_opt_fwd_tptr(jit_State *J, IRRef lim)
{
IRRef ta = fins->op1;
IRRef ref = J->chain[IR_NEWREF];
while (ref > lim) {
IRIns *newref = IR(ref);
if (ta == newref->op1 || aa_table(J, ta, newref->op1) != ALIAS_NO)
return 0; /* Conflict. */
ref = newref->prev;
}
return 1; /* No conflict. Can safely FOLD/CSE. */
}
/* ASTORE/HSTORE elimination. */
TRef LJ_FASTCALL lj_opt_dse_ahstore(jit_State *J)
{