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Re: [PATCH] Speedup tanf range reduction
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: "adhemerval dot zanella at linaro dot org" <adhemerval dot zanella at linaro dot org>, "raji at linux dot vnet dot ibm dot com" <raji at linux dot vnet dot ibm dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, nd <nd at arm dot com>
- Date: Wed, 22 Aug 2018 14:50:19 +0000
- Subject: Re: [PATCH] Speedup tanf range reduction
Adhemerval Zanella wrote:
> tanf seems to be the only place where __ieee754_rem_pio2f is used, so we
> can remove sysdeps/ieee754/flt-32/e_rem_pio2f.c and
> sysdeps/powerpc/fpu/e_rem_pio2f.c. Also, I would like to certify that
> it is faster than powerpc version (I would expect so, but at least it
> would be good to actually get some numbers).
Yes, I'm removing those and some more unused math files in my next patch.
The __ieee754_rem_pio2f for powerpc is not substantially different from the generic
version, so the performance gains will be similar. Note TOINT_INTRINSICS could
be enabled for even faster range reduction on any target that supports round() as a
single instruction.
Wilco