From: Nathan Bossart <nathandbossart@gmail.com>
To: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Cc: johncnaylorls@gmail.com
Subject: Re: Invalid control file checksum with AVX-512 during initdb on a clang19 -O0 build
Date: Wed, 11 Jun 2025 16:42:19 -0500
Message-ID: <aEn4O2qhLgtkSt7N@nathan> (raw)
In-Reply-To: <CAE-ML+-OV6p9uvCFBcSQjZUEh__y0h-KjN+BseyGJHt7u8EP+w@mail.gmail.com>
References: <CAE-ML+-OV6p9uvCFBcSQjZUEh__y0h-KjN+BseyGJHt7u8EP+w@mail.gmail.com>
(I've CC'd the committer of the feature.)
On Wed, Jun 11, 2025 at 11:10:31AM -0700, Soumyadeep Chakraborty wrote:
> We are getting a control file checksum mismatch during initdb.
>
> [...]
>
> Note that this only reproduces with clang-19 -O0 and NOT -O3. I haven't
> tried with other versions of clang.
>
> OTOH, gcc-14 is cool with both -O0 and -O3, with AVX-512 getting picked
> for both cases, for CRC instructions.
I'm wondering if there's anything else this could be besides a compiler
bug. It's interesting that -O0 is the broken case. Have you tried looking
for differences in the assembly code?
--
nathan
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To: pgsql-bugs@postgresql.org
Cc: nathandbossart@gmail.com, soumyadeep2007@gmail.com, pgsql-bugs@lists.postgresql.org, johncnaylorls@gmail.com
Subject: Re: Invalid control file checksum with AVX-512 during initdb on a clang19 -O0 build
In-Reply-To: <aEn4O2qhLgtkSt7N@nathan>
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