| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Noah Misch <noah(at)leadboat(dot)com> |
| Cc: | Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Peter Eisentraut <peter_e(at)gmx(dot)net>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Proposal: Trigonometric functions in degrees |
| Date: | 2016-01-23 20:22:14 |
| Message-ID: | 2997.1453580534@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Noah Misch <noah(at)leadboat(dot)com> writes:
> On Sat, Jan 23, 2016 at 12:08:40PM -0500, Tom Lane wrote:
>> So I pushed that, and tern/sungazer are still failing. Noah, could you
>> trace through that and see exactly where it's going off the rails?
> The second sin() is a constant, so gcc computes it immediately but sends the
> first sin() to libm. The libm sin() is slightly more accurate.
Ugh. "compile-time simplification uses different version of sin()" was
one of the theories I had in mind, but I was hoping that wasn't it
because it'd be the hardest to work around reliably. Still, I think it's
doable by caching the results of the should-be-constant subexpressions.
Will get on it.
regards, tom lane
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