Re: Disable autogeneration of gather instructions on Ryzen and generic

2018-01-11 Thread Toon Moene
On 01/09/2018 11:28 AM, Richard Biener wrote: Note that the vectorizer gives up on loops with gathers with no target support for gathers. It could simply open-code the gather though (and properly cost that open-coded variant), that's probably the way to go here. Man, I wish I had made this

Re: Disable autogeneration of gather instructions on Ryzen and generic

2018-01-09 Thread Richard Biener
On Tue, Jan 9, 2018 at 11:58 AM, Jan Hubicka wrote: >> On Tue, Jan 9, 2018 at 11:26 AM, Jan Hubicka wrote: >> > Hi, >> > gather instructions are rather hard to implement in hardware and except for >> > skylake+ chips (i.e. haswell and Zen) they seems to be rather

Re: Disable autogeneration of gather instructions on Ryzen and generic

2018-01-09 Thread Jan Hubicka
> On Tue, Jan 9, 2018 at 11:26 AM, Jan Hubicka wrote: > > Hi, > > gather instructions are rather hard to implement in hardware and except for > > skylake+ chips (i.e. haswell and Zen) they seems to be rather slow; to the > > degree I did not find real world loop where gather would

Re: Disable autogeneration of gather instructions on Ryzen and generic

2018-01-09 Thread Richard Biener
On Tue, Jan 9, 2018 at 11:26 AM, Jan Hubicka wrote: > Hi, > gather instructions are rather hard to implement in hardware and except for > skylake+ chips (i.e. haswell and Zen) they seems to be rather slow; to the > degree I did not find real world loop where gather would help on

Disable autogeneration of gather instructions on Ryzen and generic

2018-01-09 Thread Jan Hubicka
Hi, gather instructions are rather hard to implement in hardware and except for skylake+ chips (i.e. haswell and Zen) they seems to be rather slow; to the degree I did not find real world loop where gather would help on Zen. This patch simply adds a knob to disable its autogeneration (builtin