https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100173
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Hongtao.liu from comment #4)
> > but yes, cselim will also sink the first store, moving it across the
>
> Can we also sink loads?
loads are usually hoisted, not sunk.
> assign pointer to another temp pointer in both if
> and else bb, and then load val from this temp pointer. those assignments
> that in if and else branch would be finially transformed to conditional mov.
Hmm, so conditional move is faster. No, I don't think we'd do this at
the moment and I'm not sure we want in general (since aggressive
if-conversion tends to be bad).
> performance can benifit 100% with below change.
>
> for (i = 0; i < (1<<5)/2; i++) {
>
> esMetricIn = *pBranchMetric++;
>
> esMetric1 = pIn1->m_esPathMetric - esMetricIn;
> esMetric2 = pIn2->m_esPathMetric + esMetricIn;
>
> e_s16 *t1p = (esMetric1 >= esMetric2) ? &(pIn1->m_esState) :
> &(pIn2->m_esState);
> e_s16 t1 = (esMetric1 >= esMetric2) ? esMetric1 : esMetric2;
> pOut->m_esPathMetric = t1;
> pOut->m_esState = *t1p << 1;
> pOut++;
>
> esMetric1 = pIn1->m_esPathMetric + esMetricIn;
> esMetric2 = pIn2->m_esPathMetric - esMetricIn;
>
> e_s16 *t2p = (esMetric1 >= esMetric2) ? &(pIn1->m_esState) :
> &(pIn2->m_esState);
> e_s16 t2 = (esMetric1 >= esMetric2) ? esMetric1 : esMetric2;
> pOut->m_esPathMetric = t2;
> pOut->m_esState = *t2p << 1;
> pOut++;
>
> pIn1++;
> pIn2++;
> }
