Using isnan and isfinite to check for floating point exceptions
doesn't work when we want floats to be able to have infinity or NaN as
values, thus this option was removed with commit
5f71f728a3. However, we can still use
fetestexcept to explicitly check if floating point exceptions occurred
even when we can't use the feenableexcept/SIGFPE signal delivery
mechanism.
Previously, we had something like this in the
ECL_MATHERR_TEST/ECL_MATHERR_CLEAR macros, but this was not used
consistently in our codebase (the ECL_MATHERR_TEST macro was missing
in many places). Instead of error-prone testing at every point of
computation, we call fetestexcept in DO_DETECT_FPE when creating a new
float/complex float. In order to avoid having to do this twice, the
DO_DETECT_FPE2 macro is introduced.
A minor disadvantage of this strategy is that floating point
exceptions may be signaled later than they occurred.
cb03494a6d