[FFmpeg-user] Error when cross-compiling to x86 with gcc5.1

[Bernd Kuhls]

Hi,

Carl Eugen Hoyos <cehoyos at ag.or.at> wrote in news:loom.20150619T234130-167
@post.gmane.org:

>> --disable-zlib --disable-bzlib
> 
> This definitely has an effect, please be warned that 
> it also has sometimes unexpected results (like disabling 
> the png codec).

In buildroot[1] zlib and bzip2 are optional components, in my testcase with a 
minimum of features enabled they are disabled.

>> --disable-yasm
> 
> This is ok if you know (exactly) what you are doing, 
> note that as far as I am concerned the resulting 
> binaries are unsupported.

Target cpu is i586 without mmx:

install prefix            /usr
source path               .
C compiler                /home/fli4l/br9_gcc5/output/host/usr/bin/i586-
buildroot-linux-uclibc-gcc
C library                 uclibc
host C compiler           /usr/bin/gcc
host C library            glibc
ARCH                      x86 (i586)
big-endian                no
runtime cpu detection     yes
yasm                      no
MMX enabled               no
MMXEXT enabled            no
3DNow! enabled            no
3DNow! extended enabled   no
SSE enabled               no
SSSE3 enabled             no
AVX enabled               no
XOP enabled               no
FMA3 enabled              no
FMA4 enabled              no
i686 features enabled     no
CMOV is fast              no
EBX available             yes
EBP available             yes
debug symbols             yes
strip symbols             no
optimize for size         no
optimizations             yes
static                    no
shared                    yes
postprocessing support    yes
new filter support        yes
network support           yes
threading support         pthreads
safe bitstream reader     yes
SDL support               yes

> If inline asm is really broken with gcc 5.1 (this 
> is not completely unexpected), please downgrade to 
> a slightly older version (and please report this 
> to gcc).

Compiling ffmpeg with gcc 4.9.2 works fine, I did not test any other gcc5 
release but 5.1.0.

If I am reading
http://git.videolan.org/?p=ffmpeg.git;a=blob;f=configure;h=
3960b735c103ec3224e3f580aa4a91a5212a2d88;hb=HEAD#l2074
correctly then inline asm is only needed for a mmx-enabled build so disabling 
it, like in my non-mmx testcase, is ok, right?

Regards, Bernd

[1] http://git.buildroot.net/buildroot/tree/package/ffmpeg/ffmpeg.mk#n181