[libav-devel] [PATCH 1/2] configure: add support for neon intrinsics

Janne Grunau janne-libav at jannau.net
Tue Jun 17 14:54:15 CEST 2014


On 2014-06-17 13:59:17 +0200, Diego Biurrun wrote:
> On Tue, Jun 10, 2014 at 10:43:33PM +0200, Janne Grunau wrote:
> > --- a/configure
> > +++ b/configure
> > @@ -1361,6 +1361,7 @@ HAVE_LIST_PUB="
> >  HEADERS_LIST="
> >      alsa_asoundlib_h
> >      altivec_h
> > +    arm_neon_h
> >      arpa_inet_h
> >      cdio_paranoia_h
> >      cdio_paranoia_paranoia_h
> > @@ -1477,6 +1478,7 @@ TOOLCHAIN_FEATURES="
> >      gnu_as
> >      ibm_asm
> >      inline_asm_labels
> > +    neon_intrinsics
> >      pragma_deprecated
> >      symver_asm_label
> >      symver_gnu_asm
> > @@ -1639,6 +1641,7 @@ armv6_deps="arm"
> >  armv6t2_deps="arm"
> >  armv8_deps="aarch64"
> >  neon_deps_any="aarch64 arm"
> > +neon_intrinsics_deps="arm_neon_h neon"
> >  vfp_deps_any="aarch64 arm"
> >  vfpv3_deps="vfp"
> >  
> > @@ -3900,6 +3903,11 @@ EOF
> >  
> > +if enabled neon ; then
> > +    check_header arm_neon.h
> > +    check_code cc arm_neon.h "int64x2_t test" && enable neon_intrinsics
> > +fi
> 
> I wonder why you check for arm_neon.h separately, the result of that
> check is never used separately.

yes, not really needed, will be removed

> neon_intrinsics depends on neon, so the if-block should be unnecessary.

that's there to skip the check an archs except arm and aarch64, so not 
really necessary but nice to have. with arm_neon_h removed I can change it 
to:

enabled neon && check_code cc arm_neon.h "int64x2_t test" || disable neon_intrinsics

which get's rid of the if-block and fixes the logic disable/enable logic

Janne


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