From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Martin Liška <marxin.liska@gmail.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #15121: Multiple UBSAN errors
Date: Mon, 19 Mar 2018 14:20:33 -0400
Message-ID: <10573.1521483633@sss.pgh.pa.us> (raw)
In-Reply-To: <7f798f51-05c4-304a-f852-9cea35f5f095@2ndquadrant.com>
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<7df78014-c931-6c75-6f92-ec48f390b2b9@2ndquadrant.com>
<CAObPJ3MAY9u1had3QSvYO0TG-iVECqDzF04PvMZSHrmxNknZ8Q@mail.gmail.com>
<46a345c1-1f8d-fd0d-c334-d8ca577719a9@2ndquadrant.com>
<CAObPJ3OLHU2DwZLfCXEzkcqU2v6Otk6b32xo-eb0+PtEb=+BpQ@mail.gmail.com>
<7f798f51-05c4-304a-f852-9cea35f5f095@2ndquadrant.com>
Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> On 03/19/2018 03:28 PM, Martin Liška wrote:
>>>> Note that building postgresql with -03, I see some array tests failing.
> I'm getting failures in errors, union and alter_table, but none of those
> are related to arrays. So, which tests are failing for you and how do
> the failures look like?
I tried -O3 with gcc 7.3.1 (Fedora 26), and that passes check-world
just fine. Then I tried -O3 with gcc 8.0.1 (prerelease Fedora 28),
and indeed that's got some problems. It looks like array_out fails
for multidimensional arrays, because all the diffs look about
like this one:
*** 106,116 ****
SET c[2:2] = '{"new_word"}'
WHERE array_dims(c) is not null;
SELECT a,b,c FROM arrtest;
! a | b | c
! ---------------+-----------------------+-------------------
! {16,25,3,4,5} | {{{113,142},{1,147}}} | {}
! {} | {3,4} | {foo,new_word}
! {16,25,23} | {{3,4},{4,5}} | {foobar,new_word}
(3 rows)
SELECT a[1:3],
--- 106,116 ----
SET c[2:2] = '{"new_word"}'
WHERE array_dims(c) is not null;
SELECT a,b,c FROM arrtest;
! a | b | c
! ---------------+---------------+-------------------
! {16,25,3,4,5} | {{ | {}
! {} | {3,4} | {foo,new_word}
! {16,25,23} | {{3,4},{4,5}} | {foobar,new_word}
(3 rows)
SELECT a[1:3],
Note that 1-D and 2-D arrays print fine, it's only 3-D or deeper
that print wrong. Very odd. Maybe it's bad code on our part,
but I think the odds are at least as good that it's a new gcc bug.
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, tomas.vondra@2ndquadrant.com, marxin.liska@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #15121: Multiple UBSAN errors
In-Reply-To: <10573.1521483633@sss.pgh.pa.us>
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