From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: 'GNU C Library' <libc-alpha@sourceware.org>,
"tnggil@protonmail.com" <tnggil@protonmail.com>,
Joseph Myers <joseph@codesourcery.com>
Cc: nd <nd@arm.com>
Subject: Re: PPC64 libmvec sincos/sincosf ABI
Date: Tue, 6 Aug 2019 17:42:16 +0000 [thread overview]
Message-ID: <VI1PR0801MB2127D8F615416EA63BBEF4E583D50@VI1PR0801MB2127.eurprd08.prod.outlook.com> (raw)
Hi,
> 1. What is the best vector ABI (best performance) for sincos on PPC64?
> That may be a function of the particular vector instructions available on
> PPC64; the best choice of ABI on PPC64 need not correspond to the best
> choice on x86_64.
I don't think it is related to the target - the fastest ABI is one that avoids
unnecessary work. For example scalar sincos is slow due to the inefficient
ABI which forces the results through memory (fixing that gives a 50% speedup).
Similarly for the vector ABI I think returning 2 vectors in registers will be the
fastest option in all cases. The actual vector instructions shouldn't affect the
ABI beyond the vector widths that can be supported.
Wilco
next reply other threads:[~2019-08-06 17:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 17:42 Wilco Dijkstra [this message]
2019-08-06 20:31 ` PPC64 libmvec sincos/sincosf ABI Joseph Myers
2019-08-08 15:25 ` Bill Schmidt
2019-08-08 18:48 ` Bill Schmidt
2019-09-20 19:25 ` GT
2019-09-20 20:25 ` Bill Schmidt
2019-09-23 18:02 ` GT
2019-09-24 16:43 ` Bill Schmidt
-- strict thread matches above, loose matches on Subject: below --
2019-08-01 13:01 GT
2019-08-01 17:04 ` Joseph Myers
2019-08-07 21:17 ` Tulio Magno Quites Machado Filho
2019-08-08 13:33 ` Bill Schmidt
2019-08-08 15:48 ` GT
2019-08-08 15:56 ` Florian Weimer
2019-08-08 16:56 ` GT
2019-08-08 16:11 ` Bill Schmidt
2019-08-08 17:42 ` GT
2019-08-08 17:51 ` Bill Schmidt
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