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Re: [PATCH2/2] Improve performance of sinf and cosf
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, nd <nd at arm dot com>, <tuliom at linux dot ibm dot com>
- Date: Thu, 28 Jun 2018 17:34:38 +0000
- Subject: Re: [PATCH2/2] Improve performance of sinf and cosf
- References: <DB5PR08MB1030B80CCD5EC98114DFF97883490@DB5PR08MB1030.eurprd08.prod.outlook.com>
On Tue, 26 Jun 2018, Wilco Dijkstra wrote:
> + sincos_t *p = &sincosf_table[0];
Presumably using const in the first patch will also require pointers like
this in the second patch to use const as well.
Both patches should update NEWS to reflect the enhancement.
Remark, not a requirement: both the previous sinf/cosf improvements, and
this one, left k_cosf.c and k_sinf.h alone. __kernel_cosf and
__kernel_sinf are still used in e_lgammaf_r.c. It would not surprise me
if the new version was in fact faster there (even though redundant checks
for the need for range reduction would be introduced) and so k_cosf.c and
k_sinf.c could be replaced by dummy files with no code after updating
e_lgammaf_r.c.
It would also not surprise me if the new version were faster than the
versions of [ks]_{cos,sin}f.c in sysdeps/powerpc/fpu and so those are no
longer needed (or indeed faster than the POWER8 versions of cosf and sinf)
- but that would need powerpc maintainer testing.
--
Joseph S. Myers
joseph@codesourcery.com