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Tuning loop unrolling heuristics again.

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This commit is contained in:
Mike Pall 2011-05-10 16:55:23 +02:00
parent 65d9c7cb5e
commit b79cdba3a0
1 changed files with 11 additions and 3 deletions
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14
src/lj_record.c
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@ -191,6 +191,7 @@ int lj_record_objcmp(jit_State *J, TRef a, TRef b, cTValue *av, cTValue *bv)
/* Loop event. */
typedef enum {
LOOPEV_LEAVE, /* Loop is left or not entered. */
LOOPEV_ENTERLO, /* Loop is entered with a low iteration count left. */
LOOPEV_ENTER /* Loop is entered. */
} LoopEvent;
@ -316,10 +317,16 @@ static LoopEvent rec_for_iter(IROp *op, cTValue *o, int isforl)
if (isforl)
idxv += stepv;
if (rec_for_direction(&o[FORL_STEP])) {
if (idxv <= stopv) { *op = IR_LE; return LOOPEV_ENTER; }
if (idxv <= stopv) {
*op = IR_LE;
return idxv + 2*stepv > stopv ? LOOPEV_ENTERLO : LOOPEV_ENTER;
}
*op = IR_GT; return LOOPEV_LEAVE;
} else {
if (stopv <= idxv) { *op = IR_GE; return LOOPEV_ENTER; }
if (stopv <= idxv) {
*op = IR_GE;
return idxv + 2*stepv < stopv ? LOOPEV_ENTERLO : LOOPEV_ENTER;
}
*op = IR_LT; return LOOPEV_LEAVE;
}
}
@ -522,7 +529,8 @@ static void rec_loop_interp(jit_State *J, const BCIns *pc, LoopEvent ev)
*/
if (!innerloopleft(J, pc))
lj_trace_err(J, LJ_TRERR_LINNER); /* Root trace hit an inner loop. */
if ((J->loopref && J->cur.nins - J->loopref > 24) || --J->loopunroll < 0)
if ((ev != LOOPEV_ENTERLO &&
J->loopref && J->cur.nins - J->loopref > 24) || --J->loopunroll < 0)
lj_trace_err(J, LJ_TRERR_LUNROLL); /* Limit loop unrolling. */
J->loopref = J->cur.nins;
}