Re: pgsql: Fix behavior of exp() and power() for infinity inputs.

Michael Paquier <michael(at)paquier(dot)xyz> writes:
> On Sun, Jun 14, 2020 at 03:00:11PM +0000, Tom Lane wrote:
>> Also, add a bunch of test cases verifying that exp() and power()
>> actually do follow POSIX for Inf and NaN inputs. While this patch
>> should guarantee that exp() passes the tests, power() will not unless
>> the platform's pow(3) is fully POSIX-compliant. I already know that
>> gaur fails some of the tests, and I am suspicious that the Windows
>> animals will too; the extent of compliance of other old platforms
>> remains to be seen. We might choose to drop failing test cases, or
>> to work harder at overriding pow(3) for these cases, but first let's
>> see just how good or bad the situation is.

> The Windows servers don't actually cay anything here, but sidewinder
> and hoverfly complain, on top of gaur of course:
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=hoverfly&dt=2020-06-14%2015%3A05%3A33
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=sidewinder&dt=2020-06-14%2018%3A45%3A28

Yeah, and presumably Noah's other AIX critters will fail too. I'm curious
to see what damselfly will say; that's the other old-ish platform we have
in the farm. Once that reports in, I'm intending to push the attached or
something close to it. This is more or less the same thing for pow() as
the current patch did for exp(): handle Inf cases manually and then
simplify the error checks in the normal path.

regards, tom lane