| From: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Victor Wagner <vitus(at)wagner(dot)pp(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Bug fix for glibc broke freebsd build in REL_11_STABLE |
| Date: | 2018-09-04 20:59:59 |
| Message-ID: | 87in3lugm0.fsf@news-spur.riddles.org.uk |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
>>>>> "Andres" == Andres Freund <andres(at)anarazel(dot)de> writes:
Andres> Thomas and I are sitting in a cafe and are trying to figure out
Andres> what's going on...
I have a standalone test case:
#include <stdio.h>
#include <math.h>
int main(int argc, char **argv)
{
double d1 = (argc ? 1e180 : 0);
double d2 = (argv ? 1e200 : 0);
int r2 = __builtin_isinf(d1 * d2);
int r1 = isinf(d1 * d2);
printf("r1 = %d, r2 = %d\n", r1, r2);
return 0;
}
Note that swapping the r1 and r2 lines makes the problem disappear (!).
on amd64, clang 3.9.1:
cc -O2 -m32 flttst.c && ./a.out
r1 = 1, r2 = 0
cc -O2 flttst.c && ./a.out
r1 = 1, r2 = 1
Can't reproduce on 32-bit arm.
--
Andrew (irc:RhodiumToad)
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Andrew Gierth | 2018-09-04 21:14:19 | Re: Bug fix for glibc broke freebsd build in REL_11_STABLE |
| Previous Message | Michael Paquier | 2018-09-04 20:58:18 | Re: pgsql: Clean up after TAP tests in oid2name and vacuumlo. |