The attached patch ahs been regression tested on x86_64-*-freebsd.
It probably borders on obvious, but I'll ask away.  OK to commit?

2019-08-12  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/87993
	* expr.c (gfc_simplify_expr):  Simplifcation of an array with a kind
	type inquiry suffix yields a constant expression.

2019-08-12  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/87993
	* gfortran.dg/pr87993.f90: New test.

-- 
Steve