From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter@eisentraut.org>
cc: pgsql-hackers <pgsql-hackers@postgresql.org>,
        Thomas Munro <thomas.munro@gmail.com>
Subject: Re: Move MAXIMUM_ALIGNOF definition to c.h
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Comments: In-reply-to Peter Eisentraut <peter@eisentraut.org>
	message dated "Tue, 20 Jan 2026 07:48:59 +0100"
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Date: Thu, 19 Feb 2026 19:23:44 -0500
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Peter Eisentraut <peter@eisentraut.org> writes:
> As suggested at [0], we can move the computation of MAXIMUM_ALIGNOF from 
> configure.ac and meson.build to c.h.  This eliminates code duplication. 
> (For example, the AIX patch contemplates some changes, so it would be 
> good to make those in only one place.)

I looked at this but am pretty underwhelmed.  Yes, it replaces two
copies of that logic with one, but said logic is so trivial that
that's not a big win.  Moreover, I'm finding it hard to believe
that we'll ever need to change that logic again --- the plain
max-of-two-alignment-measurements logic is the way it had been
for a long time and will be again after the AIX patch lands.  I can't
foresee a future platform where it'd need to be any different.

In exchange for that simplification, we are taking a computation
that currently is done once per configure/meson-setup step, and
instead computing it during each .c file build.  I imagine that
at least the autoconf implementation is more expensive than
what the C compiler would need to do, but repeating it over and
over again will surely end up costing more.

So this doesn't seem like a good change to me.

			regards, tom lane