From: "Gabriel F. T. Gomes" <gftg@linux.vnet.ibm.com>
To: Joseph Myers <joseph@codesourcery.com>
Cc: <libc-alpha@sourceware.org>
Subject: Re: Remove powerpc32 sqrt wrappers
Date: Fri, 25 Aug 2017 01:04:00 -0000 [thread overview]
Message-ID: <20170824220422.741b2bae@keller> (raw)
In-Reply-To: <alpine.DEB.2.20.1708242028160.19765@digraph.polyomino.org.uk>
On Thu, 24 Aug 2017 20:33:10 +0000
Joseph Myers <joseph@codesourcery.com> wrote:
>Note that benchtests of sqrt deliberately use -fno-builtin, specifically
>because the point is to benchmark glibc's implementations rather than the
>compiler's inline code.
>
>Thus those benchtests may indicate how much performance (if any) is gained
>(given -fno-builtin) from the custom sqrt wrappers, compared with code
>generated by a modern GCC version that can do shrink wrapping (the
>comments in the powerpc32 wrappers say "Until gcc supports prologue
>shrink-wrapping this is the best we can do.", i.e. they were intended to
>improve on the performance of code built with old GCC). But they are also
>fairly peripheral to my main point (that in the normal case, without
>-fno-builtin, these wrappers will only ever be called for
>non-performance-relevant error cases, and not even those with
>-fno-math-errno).
Fair enough.
The patch looks good to me.
prev parent reply other threads:[~2017-08-25 1:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 22:08 Joseph Myers
2017-08-24 14:23 ` Joseph Myers
2017-08-24 19:32 ` Gabriel F. T. Gomes
2017-08-24 20:33 ` Joseph Myers
2017-08-25 1:04 ` Gabriel F. T. Gomes [this message]
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