Hi,
On 2021-06-27 16:21:46 -0400, Tom Lane wrote:
> BTW, for grins I tried building today's HEAD without -fwrapv, using
> gcc version 11.1.1 20210531 (Red Hat 11.1.1-3) (GCC)
> which is the newest version I have at hand. Not very surprisingly,
> that reproduced the failure shown on moonjell
Hello Tom,
The failure still represents a gcc bug, because we're using -fwrapv which
should disable that assumption.
Ok, I'll report it.
Done at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101254
Fixed at r12-1916-ga96d8d67d0073a7031c0712bc3fb7759417b2125
https://gcc.gnu.org/git/gitweb.
The failure still represents a gcc bug, because we're using -fwrapv which
should disable that assumption.
Ok, I'll report it.
Done at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101254
--
Fabien.
Fabien COELHO writes:
>> I suggest applying the attached in branches that have the required
>> functions.
> The proposed patch does fix the issue in pgbench TAP test. I'd suggest to
> add unlikely() on all these conditions, as already done elsewhere. See
> attached version.
Done that way, tho
Hello Tom,
moonjelly just reported an interesting failure [1].
I noticed. I was planning to have a look at it, thanks for digging!
It seems that with the latest bleeding-edge gcc, this code is
misoptimized:
else if (imax - imin < 0 || (imax - imin) + 1 < 0)
I wrote:
> ... according to the C99
> spec this code is broken, because the compiler is allowed to assume
> that signed integer overflow doesn't happen, whereupon the second
> if-block is provably unreachable. The failure still represents a gcc
> bug, because we're using -fwrapv which should disab
moonjelly just reported an interesting failure [1]. It seems that
with the latest bleeding-edge gcc, this code is misoptimized:
/* check random range */
if (imin > imax)
{
pg_log_error("empty range given to random");
