On x86, expm1 (1e5) properly returns an infinity with errno set to ERANGE - but does not raise the OVERFLOW exception.  On x86_64, OVERFLOW is properly raised.

Testcase:

#include <errno.h>
#include <fenv.h>
#include <math.h>
#include <stdio.h>
#include <float.h>

volatile double d = 1e5;

int
main (void)
{
  feclearexcept (FE_ALL_EXCEPT);
  errno = 0;
  volatile double r = expm1 (d);
  if (fetestexcept (FE_DIVBYZERO))
    printf ("DIVBYZERO ");
  if (fetestexcept (FE_INEXACT))
    printf ("INEXACT ");
  if (fetestexcept (FE_INVALID))
    printf ("INVALID ");
  if (fetestexcept (FE_OVERFLOW))
    printf ("OVERFLOW ");
  if (fetestexcept (FE_UNDERFLOW))
    printf ("UNDERFLOW ");
  printf ("%.18g %m\n", r);
  return 0;
}

Result:

inf Numerical result out of range