Horton

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

Euler Taveira <euler@timbira.com.br>

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From: Euler Taveira <euler@timbira.com.br>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Huong Dangminh <huo-dangminh@ys.jp.nec.com>, "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: 2018-04-11T04:10:29Z
Lists: pgsql-bugs, pgsql-hackers 
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.


[1] https://docs.microsoft.com/en-us/cpp/porting/floating-point-migration-issues
[2] https://msdn.microsoft.com/pt-br/library/e7s85ffb.aspx


-- 
   Euler Taveira                                   Timbira -
http://www.timbira.com.br/
   PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento

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.