Hi, On Fri, May 6, 2016 at 8:02 PM, James Almer <jamr...@gmail.com> wrote:
> On 5/6/2016 8:48 PM, Timothy Gu wrote: > > On Fri, May 06, 2016 at 12:08:14PM +0200, Hendrik Leppkes wrote: > >> > >> Just to document it, this has caused build breakage in various > >> scenarios, even in GCC 5.3 (6.1 not tested). > >> > >> The latest reported on IRC just today here: > >> libavcodec/sbrdsp.c: In function 'sbr_neg_odd_64_c': > >> libavcodec/sbrdsp.c:47:13: internal compiler error: in > >> vect_analyze_data_ref_accesses, at tree-vect-data-refs.c:2596 > >> static void sbr_neg_odd_64_c(float *x) > >> > >> There are various other cases which usually involve inline asm when > >> building with SIMD (ie. --cpu=host) and the optimizer running out of > >> registers, for example: > >> libavcodec/x86/cabac.h:192:5: error: 'asm' operand has impossible > constraints > >> > >> IMHO this feature is not quite ready to be enabled unconditionally in > >> our code base, and we should re-evaluate this change. > > > > I don't have a problem with reverting this commit, but as James > mentioned I do > > prefer the bug to be reported to GCC if possible. > > > > Have you also considered the possibility to enable this feature only if > inline > > assembly is not enabled? > > Nobody disables inline asm when using GCC, so it'd be the same as removing > tree > vectorization altogether to begin with. > > This feature gives some nice speed boost on parts of the code that don't > have > hand written asm, so I'd very much rather keep it and try to get GCC to > fix bugs > on their compilers. Which codepaths are sped up _specifically_? If there's anything where it's significant and important, we can hand-write assembly for it. Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
