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Re: [PATCH 2/6] Remove slow paths from sin/cos
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Steve Ellcey <sellcey at cavium dot com>
- Cc: Zack Weinberg <zackw at panix dot com>, Ondřej Bílka <neleai at seznam dot cz>, Siddhesh Poyarekar <siddhesh at gotplt dot org>, Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, nd <nd at arm dot com>
- Date: Sat, 10 Mar 2018 00:52:09 +0000
- Subject: Re: [PATCH 2/6] Remove slow paths from sin/cos
- Authentication-results: sourceware.org; auth=none
- References: <CAKCAbMg85h8JLK1qUNUgUUDVwU2WCnD4WCCputCM7qhr7y0i6w@mail.gmail.com> <1520636722.6774.157.camel@cavium.com>
On Fri, 9 Mar 2018, Steve Ellcey wrote:
> And yet we have tests for large numbers in auto-libm-test-out-sin
> and auto-libm-test-out-cos. I was testing a different vector sin/cos
Yes. A floating-point number represents a particular real number, not an
interval, so all the usual accuracy goals (of results within a few ulps of
the correct answer) apply for large inputs (but performance is not a
concern for those inputs). Only for IBM long double is this relaxed, to
treat values not representable in 106 mantissa bits as if they do
represent intervals.
--
Joseph S. Myers
joseph@codesourcery.com