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Re: [PATCH] Compile AVX libm functions with -mavx


On Tue, Oct 02, 2012 at 03:31:50PM -0400, Mike Frysinger wrote:
> On Tuesday 02 October 2012 15:20:54 H.J. Lu wrote:
> > On Tue, Oct 2, 2012 at 12:02 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> > > On Tuesday 02 October 2012 09:53:25 H.J. Lu wrote:
> > >> This patch compiles AVX libm functions with -mavx.  It reduces text size
> > > 
> > >> of libm.so by about 1%:
> > > looks like you're reverting 56f6f6a2403cfa7267cad722597113be35ecf70d.
> > > shouldn't you revert all of it and not just change the CFLAGS back ?
> > 
> > Doesn't this patch:
> > 
> > http://sourceware.org/ml/libc-alpha/2012-10/msg00055.html
> > 
> > do that?
> 
> yes, i missed the follow up
> 
> > > it'd be useful to know *why* Ulrich moved away from -mavx, but
> > > unfortunately his commit message is useless.
> > 
> > I can only guess:
> 
> might be useful to put some notes (like referring to the older commit) into 
> the commit message when you do commit things
> -mike

could it be a 60 cycle penalty when switching between legagy sse and avx
state?

-- 

high pressure system failure


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