Re: [PATCH v2] powerpc/math-emu: Update macros from gmp-6.1.2

On Tue, Nov 20, 2018 at 12:15 PM Segher Boessenkool
[off-list ref] wrote:

On Tue, Nov 20, 2018 at 10:45:19AM -0800, Nick Desaulniers wrote:

quoted

On Tue, Nov 20, 2018 at 10:20 AM Segher Boessenkool
[off-list ref] wrote:

quoted

quoted

Segher, which tree contains the One True Upstream for longlong.h?

You should probably get your updates from the same place as was used to
get the file in the first place.

So sounds like GMP is the source to take then.

I'm pretty sure the kernel got it from GCC.
How much does the kernel
one differ from current GCC?

Compare udiv_qrnnd implementations from:
gcc: https://github.com/gcc-mirror/gcc/blob/f7289f563a5e447ac21a5901ed75aad0dbd37732/include/longlong.h#L1679
gmp: https://gmplib.org/repo/gmp/file/tip/longlong.h#l2063

The kernel currently is using the GCC impl, which Joel's patch here
changes it to the GMP impl.

If you prefer the kernel to keep the kernel keep the GCC derivative,
then Joel can drop the change to udiv_qrnnd() as it does not contain
inline assembly relevant to the original issue.
-- 
Thanks,
~Nick Desaulniers