Horton

RE: power() function in Windows: "value out of range: underflow"

Huong Dangminh <huo-dangminh@ys.jp.nec.com>

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From: Huong Dangminh <huo-dangminh@ys.jp.nec.com>
To: Euler Taveira <euler@timbira.com.br>, David Rowley <david.rowley@2ndquadrant.com>
Cc: "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>, "Pg Hackers" <pgsql-hackers@postgresql.org>, Akio Iwaasa <aki-iwaasa@vt.jp.nec.com>
Date: 2018-04-11T04:42:04Z
Lists: pgsql-bugs, pgsql-hackers

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Thanks for confirming.
 
> 2018-04-11 0:13 GMT-03:00 David Rowley <david.rowley@2ndquadrant.com>:
> > I can recreate this when building with MSVC 2012. I confirm that I see
> > the same as you. Microsoft are setting errno to EDOM in the above 3
> > cases, where in Linux the result is still NaN, just the errno is not
> > set.
> >
> FWIW, I tested in MSVC 2017 (15.6.4) and it worked like expected.
> Looking at [1], it seems there could be nasty bugs when using math functions
> in MSVC < 2013 (or 2015). I don't have some older MSVC here to try
> /fp:OPTIONHERE [2] to see if it makes any difference.

Thanks.
Anyway currently PostgreSQL installers seem not be compiled with MSVC 2017, 
so it should be fix for current users?
I updated the patch as David Rowley mentioned.


---
Thanks and best regards,
Dang Minh Huong
NEC Solution Innovators, Ltd.
http://www.nec-solutioninnovators.co.jp/en/

Commits

  1. Revert back-branch changes in power()'s behavior for NaN inputs.

  2. Avoid wrong results for power() with NaN input on more platforms.

  3. Avoid wrong results for power() with NaN input on some platforms.