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Date: Mon, 16 Mar 2026 08:13:55 -0400
From: "Greg Burd" <greg@burd.me>
To: "Tom Lane" <tgl@sss.pgh.pa.us>, "Michael Paquier" <michael@paquier.xyz>,
 "Alexander Lakhin" <exclusion@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>,
 "Thomas Munro" <thomas.munro@gmail.com>
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 <abdYBpgtoRQV34PX@paquier.xyz> <2284079.1773625237@sss.pgh.pa.us>
Subject: Re: pgcrypto/des tests fail on riscv64 due to clang's code generation
 anomaly
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On Sun, Mar 15, 2026, at 9:40 PM, Tom Lane wrote:
> Michael Paquier <michael@paquier.xyz> writes:
>> On Sun, Mar 15, 2026 at 02:00:00PM +0200, Alexander Lakhin wrote:
>>> adding -march=rv64gcv to CFLAGS makes clang generate different (wrong?)
>>> code for crypt-des.c. Namely, having reproduced the diff locally, with
>>> this debugging addition:
>>> when the code compiled with CC=clang-20 CPPFLAGS="-march=rv64gcv".
>
>> Thanks for the detailed investigation.  I was puzzled by it myself for
>> a couple of hours, and did not see something else than a broken
>> compiler here..
>
> Seems like this might be worth a bug report to the clang people.

Thanks Alexander for digging and a solid report of the issue, and Michael for spending some time on this, and Tom for chiming in as well.  I agree this looks like a compiler issue.  I know that Thomas (added/CC'ed) you've posted bugs against clang before, any thoughts on this one?

>
> 			regards, tom lane

best.

-greg