Re: Bug fix for glibc broke freebsd build in REL_11_STABLE

>>>>> "Andres" == Andres Freund <andres@anarazel.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)