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Improve coalescing of multiple KPRI instructions to KNIL.

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This commit is contained in:
Mike Pall 2010-09-01 00:18:00 +02:00
parent 00d10711ae
commit 8876704e05
1 changed files with 42 additions and 39 deletions
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81
src/lj_parse.c
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@ -419,14 +419,48 @@ static void expr_discharge(FuncState *fs, ExpDesc *e)
e->k = VRELOCABLE;
}
/* Emit bytecode to set a range of registers to nil. */
static void bcemit_nil(FuncState *fs, BCReg from, BCReg n)
{
if (fs->pc > fs->lasttarget) { /* No jumps to current position? */
BCIns *ip = &fs->bcbase[fs->pc-1].ins;
BCReg pto, pfrom = bc_a(*ip);
switch (bc_op(*ip)) { /* Try to merge with the previous instruction. */
case BC_KPRI:
if (bc_d(*ip) != ~LJ_TNIL) break;
if (from == pfrom) {
if (n == 1) return;
} else if (from == pfrom+1) {
from = pfrom;
n++;
} else {
break;
}
fs->pc--; /* Drop KPRI. */
break;
case BC_KNIL:
pto = bc_d(*ip);
if (pfrom <= from && from <= pto+1) { /* Can we connect both ranges? */
if (from+n-1 > pto)
setbc_d(ip, from+n-1); /* Patch previous instruction range. */
return;
}
break;
default:
break;
}
}
/* Emit new instruction or replace old instruction. */
bcemit_INS(fs, n == 1 ? BCINS_AD(BC_KPRI, from, VKNIL) :
BCINS_AD(BC_KNIL, from, from+n-1));
}
/* Discharge an expression to a specific register. Ignore branches. */
static void expr_toreg_nobranch(FuncState *fs, ExpDesc *e, BCReg reg)
{
BCIns ins;
expr_discharge(fs, e);
if (e->k <= VKTRUE) {
ins = BCINS_AD(BC_KPRI, reg, const_pri(e));
} else if (e->k == VKSTR) {
if (e->k == VKSTR) {
ins = BCINS_AD(BC_KSTR, reg, const_str(fs, e));
} else if (e->k == VKNUM) {
lua_Number n = expr_numV(e);
@ -442,6 +476,11 @@ static void expr_toreg_nobranch(FuncState *fs, ExpDesc *e, BCReg reg)
if (reg == e->u.s.info)
goto noins;
ins = BCINS_AD(BC_MOV, reg, e->u.s.info);
} else if (e->k == VKNIL) {
bcemit_nil(fs, reg, 1);
goto noins;
} else if (e->k <= VKTRUE) {
ins = BCINS_AD(BC_KPRI, reg, const_pri(e));
} else {
lua_assert(e->k == VVOID || e->k == VJMP);
return;
@ -577,42 +616,6 @@ static void bcemit_method(FuncState *fs, ExpDesc *e, ExpDesc *key)
e->k = VNONRELOC;
}
/* Emit bytecode to set a range of registers to nil. */
static void bcemit_nil(FuncState *fs, BCReg from, BCReg n)
{
if (fs->pc > fs->lasttarget) { /* No jumps to current position? */
BCIns *ip = &fs->bcbase[fs->pc-1].ins;
BCReg pto, pfrom = bc_a(*ip);
switch (bc_op(*ip)) { /* Try to merge with the previous instruction. */
case BC_KPRI:
if (bc_d(*ip) != ~LJ_TNIL) break;
if (from == pfrom) {
if (n == 1) return;
} else if (from == pfrom+1) {
from = pfrom;
n++;
} else {
break;
}
fs->pc--; /* Drop KPRI. */
break;
case BC_KNIL:
pto = bc_d(*ip);
if (pfrom <= from && from <= pto+1) { /* Can we connect both ranges? */
if (from+n-1 > pto)
setbc_d(ip, from+n-1); /* Patch previous instruction range. */
return;
}
break;
default:
break;
}
}
/* Emit new instruction or replace old instruction. */
bcemit_INS(fs, n == 1 ? BCINS_AD(BC_KPRI, from, VKNIL) :
BCINS_AD(BC_KNIL, from, from+n-1));
}
/* -- Bytecode emitter for branches --------------------------------------- */
/* Emit unconditional branch. */