[FFmpeg-devel] [PATCH v2 2/2] swscale: Fix AltiVec/VSX build with recent GCC

[Reimar Döffinger]

On 07.08.2019, at 19:39, Daniel Kolesa <daniel at octaforge.org> wrote:

> The argument to vec_splat_u16 must be a literal. By making the
> function always inline and marking the arguments const, gcc can
> turn those into literals, and avoid build errors like:

Why marking the arguments const?
If it depends on that it sounds like this might be really unreliable and just work or not work with random compiler versions.
It would also be nice to know if/what the impact on code size or performance would be of always inline.
An alternative, uglier but likely more reliable option would be to pass the vswap/vshift vectors as arguments and have a macro that generates them (admit the multiple-evaluation risks though)
e.g.
#define yuv2plane1_16_vsx(s, d, w, b, o) yuv2plane1_16_vsx(s, d, w, b, o, vec_splat_u16(b ? 8 : 0))