Re: Add support for AT LOCAL - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Add support for AT LOCAL
Date
Msg-id 2188264.1697425365@sss.pgh.pa.us
Whole thread Raw
In response to Re: Add support for AT LOCAL  (Thomas Munro <thomas.munro@gmail.com>)
Responses Re: Add support for AT LOCAL
List pgsql-hackers
Thomas Munro <thomas.munro@gmail.com> writes:
> On Mon, Oct 16, 2023 at 2:58 PM Michael Paquier <michael@paquier.xyz> wrote:
>> Another theory would be one of these weird compiler optimization issue
>> from xlc?  In recent history, there was 8d2a01ae12cd.

> Yeah, there are more like that too.  xlc 12.1 is dead (like the OS
> version it shipped with).  New versions are available on cfarm if we
> care about this target.  But I am conscious of the cosmic law that if
> you blame the compiler too soon you can cause the bug to move into
> your code...

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.

            regards, tom lane



pgsql-hackers by date:

Previous
From: Thomas Munro
Date:
Subject: Re: Add support for AT LOCAL
Next
From: Erik Wienhold
Date:
Subject: Re: Patch: Improve Boolean Predicate JSON Path Docs