stfc
Update SIR to use Dawn intrinsics (min, max etc).
At the moment Fortran intrinsics are replaced by equivalent code before being transformed to SIR. However, Dawn does support a number of intrinsics so these can be translated directly.
The Fortran intrinsics used in the tracer advection example are MAX, SIGN, MIN and ABS.
I can't find any examples of using intrinsics in the dawn repo or in any previously supplied code so I've contacted Matthias requesting an example.
Matthias has kindly pointed me at the following https://github.com/MeteoSwiss-APN/dawn/blob/407c03b2024e5a224548b173a39e7ba2245ca060/dawn/test/integration-test/dawn4py-tests/ICON_laplacian_diamond_stencil.py#L179
Essentially the structure appears to be ...
serial_utils.make_fun_call_expr("intrinsic",[args])
Done a first implementation which probably has various syntax errors but they can be simply fixed. The main question is how to deal with sign as apparently C does not have a standard implementation of SIGN. Perhaps I should just use the transformation. I'll ask Matthias what he thinks as he has talked about using an intrinsic in the past.
C does have its own implementation of copysign since C99: https://en.cppreference.com/w/c/numeric/math/copysign
Is this different to Fortran's? I remember using it (or my own implementation of it due to performance) in the Regent version of NemoLite2D
