Date: Wed, 11 Mar 2026 15:51:46 +0000
From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter@eisentraut.org>,
	Andres Freund <andres@anarazel.de>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: Defend against -ffast-math in meson builds
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Hi,

On Wed, Mar 11, 2026 at 11:19:45AM -0400, Tom Lane wrote:
> Peter Eisentraut <peter@eisentraut.org> writes:
> > The existing check in configure is because certain Linux distributions 
> > used to compile everything with -ffast-math to be "faster", and that 
> > kept breaking PostgreSQL and so we wanted to stop them very early. 
> > These are gone, and the defenses in the code like date.c should be 
> > sufficient for any new attempts.  I think we could remove the check in 
> > configure.
> 
> The defenses in those modules are probably obsolete too: aren't they about
> ensuring exact results with floating-point timestamps?  My gut reaction to
> this was maybe we could remove *all* of that, so now I'm curious what
> problem Bertrand ran into.

I got some regression tests failing: [1].

[1]: https://postgr.es/m/abGO%2BBl1FQlpvFAt%40ip-10-97-1-34.eu-west-3.compute.internal

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com