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

[Richard Sandiford <richard.sandiford@linaro.org>]

Robin Dapp <rdapp@linux.vnet.ibm.com> writes:
>> 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.

Ah, makes sense now, thanks.  Would you mind putting something like
that last sentence in a comment?

> 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 :)

Yeah :-)  But thanks for the series, looks like a nice improvement.

Richard