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Re: [PATCH] powerpc: Fix build of wcscpy with --disable-multi-arch
Hi Adhemerval,
> These kind of optimizations might made sense when the default deployment
> was for chips which do not support fast instructions or when compiler did
> not have a better alternative implemented. If I recall correctly I
> implemented these when most distro used for powerpc64 was RHEL6 and its
> compiler (gcc 4.4 if I am not mistaken) was targeting power4 and did not
> such builtin optimization.
Well that was a very long time ago, back in 2005 GCC added support for inlining
copysign... This is why we used to have many inlines in GLIBC header files.
> And I agree we with you that nowadays mostly powerpc ifunc implementation are
> not adding anything in term of performance. Maybe a future would be indeed
> cleanup useless ifunc variants and just use the compiler builtins.
Yes, even if ifuncs made sense 15+ years ago, today there is no benefit at all.
All internal uses of copysign are inlined using fcpsgn in eg. powerpc64le-linux-gnu
and the power4 sequence for the power4 variants.
Cheers,
Wilco