From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
Cc: pgsql-hackers@lists.postgresql.org, David Rowley <dgrowleyml@gmail.com>
Subject: Re: Recent failures on buildfarm member hornet
Date: Wed, 07 Oct 2020 13:13:18 -0400
Message-ID: <2233910.1602090798@sss.pgh.pa.us> (raw)
In-Reply-To: <20201007021941.GD1422897@rfd.leadboat.com>
References: <1830491.1601944935@sss.pgh.pa.us>
<20201007014507.GB1422897@rfd.leadboat.com>
<2040113.1602035809@sss.pgh.pa.us>
<20201007021941.GD1422897@rfd.leadboat.com>
Noah Misch <noah@leadboat.com> writes:
> On Tue, Oct 06, 2020 at 09:56:49PM -0400, Tom Lane wrote:
>> Now that *is* surprising. Could you poke a little further to determine
>> which module is getting miscompiled? (gram.o seems like the next most
>> likely bet.)
> gram.o was it. (The way I rebuilt gram.o also rebuilt parser.o and scan.o,
> but those seem far less likely.)
This suggests that the problem is misoptimization of gram.y's
makeOrderedSetArgs:
/* don't merge into the next line, as list_concat changes directargs */
ndirectargs = list_length(directargs);
return list_make2(list_concat(directargs, orderedargs),
makeInteger(ndirectargs));
I think that if the compiler did what the comment says not to, it'd match
this symptom. However, I'm baffled as to why our recent pg_list.h changes
would've affected that.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, noah@leadboat.com, dgrowleyml@gmail.com
Subject: Re: Recent failures on buildfarm member hornet
In-Reply-To: <2233910.1602090798@sss.pgh.pa.us>
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