ranger: Improve CLZ fold_range [PR115337]

ranger: Improve CLZ fold_range [PR115337]

cfn_ctz::fold_range includes special cases for the case where .CTZ has
two arguments and so is well defined at zero, and the second argument is
equal to prec or -1, but cfn_clz::fold_range does that only for the prec
case.  -1 is fairly common as well though, because the <stdbit.h> builtins
do use it now, so I think it is worth special casing that.
If we don't know anything about the argument, the difference for
.CLZ (arg, -1) is that previously the result was varying, now it will be
[-1, prec-1].  If we knew arg can't be zero, it used to be optimized before
as well into e.g. [0, prec-1] or similar.

2024-06-04  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/115337
	* gimple-range-op.cc (cfn_clz::fold_range): For
	m_gimple_call_internal_p handle as a special case also second argument
	of -1 next to prec.