Re: [PATCH 2/5 v3] Vect peeling cost model

[Robin Dapp <rdapp at linux dot vnet dot ibm dot com>]

> Not sure I've understood the series TBH, but is the npeel == vf / 2
> there specifically for the "unknown number of peels" case?  How do
> we distinguish that from the case in which the number of peels is
> known to be vf / 2 at compile time?  Or have I missed the point
> completely? (probably yes, sorry!)

Good point, that's not totally waterproof for future uses of
vect_get_peeling_costs_all_drs ().  Currently, however, only when
peeling for unknown alignment vf != 0 will be passed to it (and vf == 0
for the known alignment case), so we can distinguish the cases.

In future, the whole vf/2 handling should be improved anyway since e.g.
it is hardcoded here as well as in tree-vect-loop.c.  npeel = 0 also has
a double meaning, namely not peeling when peeling for known alignment
and peeling vf/2 iters when peeling for unknown alignment.  Room for
improvement I guess :)

Regards
 Robin