how *not* to use denormalised numbers?

[Anton Shterenlikht]

Are denormalised numbers supported by default by gfortran6 (or 5)?
My understanding was that the use has to request
the use of denormalised numbers explicitly, via USE statement,
e.g. MFE, p.225.

I have a program that does *not* USE ieee_features,
compiled by gfortran6 with these flags:

-fopenmp -fbacktrace -Wall

It returns (FreeBSD amd64):

Note: The following floating-point exceptions are signalling: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

suggesting denormalised numbers were used.

I don't want to use denormalised numbers.
A flash to zero is acceptable, provided
this will trigger underflow exception.
What gfortran option(s) will achieve this?

Thanks

Anton