On Sat, May 7, 2016 at 2:02 AM, 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.
Fixing would be nice of course, but it should then only be enabled in versions we know do not have problems, which is none right now. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel