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Fix recording of loops with instable directions in side traces.

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This commit is contained in:
Mike Pall 2011-06-20 21:51:31 +02:00
parent 31d566428f
commit 4df40a228f
1 changed files with 7 additions and 6 deletions
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13
src/lj_record.c
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@ -333,14 +333,15 @@ static LoopEvent rec_for_iter(IROp *op, cTValue *o, int isforl)
}
/* Record checks for FOR loop overflow and step direction. */
static void rec_for_check(jit_State *J, IRType t, int dir, TRef stop, TRef step)
static void rec_for_check(jit_State *J, IRType t, int dir,
TRef stop, TRef step, int init)
{
if (!tref_isk(step)) {
/* Non-constant step: need a guard for the direction. */
TRef zero = (t == IRT_INT) ? lj_ir_kint(J, 0) : lj_ir_knum_zero(J);
emitir(IRTG(dir ? IR_GE : IR_LT, t), step, zero);
/* Add hoistable overflow checks for a narrowed FORL index. */
if (t == IRT_INT) {
if (init && t == IRT_INT) {
if (tref_isk(stop)) {
/* Constant stop: optimize check away or to a range check for step. */
int32_t k = IR(tref_ref(stop))->i;
@ -357,7 +358,7 @@ static void rec_for_check(jit_State *J, IRType t, int dir, TRef stop, TRef step)
emitir(IRTI(IR_USE), tr, 0); /* ADDOV is weak. Avoid dead result. */
}
}
} else if (t == IRT_INT && !tref_isk(stop)) {
} else if (init && t == IRT_INT && !tref_isk(stop)) {
/* Constant step: optimize overflow check to a range check for stop. */
int32_t k = IR(tref_ref(step))->i;
k = (int32_t)(dir ? 0x7fffffff : 0x80000000) - k;
@ -384,8 +385,7 @@ static void rec_for_loop(jit_State *J, const BCIns *fori, ScEvEntry *scev,
scev->dir = dir;
scev->stop = tref_ref(stop);
scev->step = tref_ref(step);
if (init)
rec_for_check(J, t, dir, stop, step);
rec_for_check(J, t, dir, stop, step, init);
scev->start = tref_ref(find_kinit(J, fori, ra+FORL_IDX, IRT_INT));
tc = (LJ_DUALNUM &&
!(scev->start && irref_isk(scev->stop) && irref_isk(scev->step) &&
@ -447,7 +447,8 @@ static LoopEvent rec_for(jit_State *J, const BCIns *fori, int isforl)
}
tr[FORL_EXT] = tr[FORL_IDX];
stop = tr[FORL_STOP];
rec_for_check(J, t, rec_for_direction(&tv[FORL_STEP]), stop, tr[FORL_STEP]);
rec_for_check(J, t, rec_for_direction(&tv[FORL_STEP]),
stop, tr[FORL_STEP], 1);
}
ev = rec_for_iter(&op, tv, isforl);