Date: Sun, 15 Oct 2023 21:58:04 -0700
From: Noah Misch <noah@leadboat.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Thomas Munro <thomas.munro@gmail.com>,
	Michael Paquier <michael@paquier.xyz>,
	Vik Fearing <vik@postgresfriends.org>,
	cary huang <hcary328@gmail.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: Add support for AT LOCAL
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On Sun, Oct 15, 2023 at 11:30:17PM -0400, Tom Lane wrote:
> Thomas Munro <thomas.munro@gmail.com> writes:
> > On Mon, Oct 16, 2023 at 4:02 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> I'm having a hard time not believing that this is a compiler bug.
> >> Looking back at 8d2a01ae12cd and its speculation that xlc is overly
> >> liberal about reordering code around sequence points ... I wonder
> >> if it'd help to do this calculation in a local variable, and only
> >> assign the final value to result->time ?  But we have to reproduce
> >> the problem first.
> 
> > If that can be shown I would vote for switching to /opt/IBM/xlc/16.1.0
> > and not changing a single bit of PostgreSQL.
> 
> If switching to 16.1 removes the failure, I'd agree.  It's hard
> to believe that any significant number of users still care about
> building PG with xlc 12.

Works for me.  I've started a test run with the xlc version change.