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small optimization

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This commit is contained in:
Roberto Ierusalimschy 2005-10-13 09:21:51 -03:00
parent cd12ab2597
commit e9b06c506f
1 changed files with 12 additions and 15 deletions
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27
lcode.c
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@ -123,20 +123,22 @@ static int need_value (FuncState *fs, int list) {
}
static void patchtestreg (Instruction *i, int reg) {
if (reg != NO_REG)
static int patchtestreg (FuncState *fs, int node, int reg) {
Instruction *i = getjumpcontrol(fs, node);
if (GET_OPCODE(*i) != OP_TESTSET)
return 0; /* cannot patch other instructions */
if (reg != NO_REG && reg != GETARG_B(*i))
SETARG_A(*i, reg);
else /* no register to put value; change TESTSET to TEST */
else /* no register to put value or register already has the value */
*i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
return 1;
}
static void removevalues (FuncState *fs, int list) {
for (; list != NO_JUMP; list = getjump(fs, list)) {
Instruction *i = getjumpcontrol(fs, list);
if (GET_OPCODE(*i) == OP_TESTSET)
patchtestreg(i, NO_REG);
}
for (; list != NO_JUMP; list = getjump(fs, list))
patchtestreg(fs, list, NO_REG);
}
@ -144,11 +146,8 @@ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
int dtarget) {
while (list != NO_JUMP) {
int next = getjump(fs, list);
Instruction *i = getjumpcontrol(fs, list);
if (GET_OPCODE(*i) == OP_TESTSET) {
patchtestreg(i, reg);
if (patchtestreg(fs, list, reg))
fixjump(fs, list, vtarget);
}
else
fixjump(fs, list, dtarget); /* jump to default target */
list = next;
@ -392,9 +391,7 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
int p_f = NO_JUMP; /* position of an eventual LOAD false */
int p_t = NO_JUMP; /* position of an eventual LOAD true */
if (need_value(fs, e->t) || need_value(fs, e->f)) {
int fj = NO_JUMP; /* first jump (over LOAD ops.) */
if (e->k != VJMP)
fj = luaK_jump(fs);
int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
p_f = code_label(fs, reg, 0, 1);
p_t = code_label(fs, reg, 1, 0);
luaK_patchtohere(fs, fj);