[Pixman] [PATCH 1/2] autotools: use custom build rule to build iwMMXt code

Matt Turner mattst88 at gmail.com
Tue Jul 30 13:08:42 PDT 2013

On Sat, Jul 27, 2013 at 10:35 AM, Siarhei Siamashka
<siarhei.siamashka at gmail.com> wrote:
> configure:13042: checking whether to use ARM IWMMXT intrinsics
> configure:13068: gcc -c -g -O2 -Wall -fno-strict-aliasing -fvisibility=hidden -flax-vector-conversions -Winline -march=iwmmxt2  conftest.c >&5
> conftest.c:1:0: sorry, unimplemented: iWMMXt and hardware floating point

This error is because your gcc is too old. I can't remember exactly
but I think >=4.7 is needed to build the iwMMXt code with hardfp.
>=4.7 is certainly needed for working iwMMXt support at all.

I suppose since I'm not attempting to get an optimized pixman build
into OLPC's releases with a patched gcc anymore that I should change

#if defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 5))
#error "Need GCC >= 4.5 for IWMMXT intrinsics"

to match the upstream gcc version that contains the necessary support.

Julien, what version of gcc are you using? We may do better to simply
avoid the issue (by raising the required gcc version) until someone at
OLPC patches gcc to support a -miwmmxt flag.

Daniel, anyone working on that?

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