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Subject: Re: pgcrypto: remove useless px_memset() and BF_ASM
From: Daniel Gustafsson <daniel@yesql.se>
In-Reply-To: <87ldew2yqu.fsf@wibble.ilmari.org>
Date: Thu, 9 Apr 2026 22:07:09 +0300
Cc: pgsql-hackers@lists.postgresql.org
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Message-Id: <9B96C179-32FA-4715-BC26-4E31D9EFF3A2@yesql.se>
References: <87ldew2yqu.fsf@wibble.ilmari.org>
To: =?utf-8?Q?Dagfinn_Ilmari_Manns=C3=A5ker?= <ilmari@ilmari.org>
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> On 9 Apr 2026, at 13:51, Dagfinn Ilmari Manns=C3=A5ker =
<ilmari@ilmari.org> wrote:

> In the thread about centralised architecture detection, I noticed that
> the BF_ASM macro in crypt-blowfish.c has never been defined to =
anything
> but 0, and the _BF_body_r() function it would call has never existed, =
so
> that can be got rid of.

Agreed.  I didn't do enough archaeology to figure out what upstream =
has/had or
why it was removed, but it's been dead for 25 odd years so it's about =
time to
remove.

> While investigating at that, I also noticed that px_memset(), which =
has
> the comment /* memset that must not be optimized away */, is only ever
> called with zero for the value, which could be better written with
> explicit_bzero() now that we have that.

One could imagine various tricks for rewriting px_memset to =
explicit_bzero in
order to reduce the churn, but since this code is very rarely =
backpatched into
it's not a big problem IMHO.

I'll have another look with fresh eyes once back in the office.

--
Daniel Gustafsson