Jiawei: > This patch modifies the FFmpeg build system to remove the explicit disabling > of GCC's auto-vectorization feature. > > Modern GCC versions (>= 10.0) have demonstrated stable auto-vectorization > capabilities through extensive optimizations in loop analysis and SIMD > code generation. The explicit -fno-tree-vectorize flag originally added > in commit 973859f (2009) to workaround early GCC vectorization instability > is no longer necessary. > > Key improvements justifying this change: > 1. Enhanced heuristics for loop vectorization cost models > 2. Mature handling of alignment and memory access patterns > 3. Robust fallback mechanisms for unsupported architectures > > This change allows FFmpeg to benefit from automated SIMD optimizations > when built with -O3 optimization level, particularly improving > performance on x86_64 (AVX), ARM64 (SVE) and RISC-V(RVV) architectures. > > [1] > https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/973859f5230e77beea7bb59dc081870689d6d191 > > --- > configure | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/configure b/configure > index 3730b0524c..b9e95ce4ec 100755 > --- a/configure > +++ b/configure > @@ -7656,7 +7656,6 @@ if enabled icc; then > disable aligned_stack > fi > elif enabled gcc; then > - check_optflags -fno-tree-vectorize > check_cflags -Werror=format-security > check_cflags -Werror=implicit-function-declaration > check_cflags -Werror=missing-prototypes
FYI: The last discussion about auto-vectorization is here: https://ffmpeg.org/pipermail/ffmpeg-devel/2022-July/299405.html It contains a report about a failing build with vectorization enabled: https://ffmpeg.org/pipermail/ffmpeg-devel/2022-July/299421.html I don't know whether this is still reproducible with the latest GCC. - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
