New flag -fdec-math for COTAN and degree trig intrinsics.

New flag -fdec-math for COTAN and degree trig intrinsics.

2016-10-11  Fritz Reese  <fritzoreese@gmail.com>

New flag -fdec-math for COTAN and degree trig intrinsics.

	gcc/fortran/
	* lang.opt: New flag -fdec-math.
	* options.c (set_dec_flags): Enable with -fdec.
	* invoke.texi, gfortran.texi, intrinsic.texi: Update documentation.
	* intrinsics.c (add_functions, do_simplify): New intrinsics
	with -fdec-math.
	* gfortran.h (gfc_isym_id): New isym GFC_ISYM_COTAN.
	* gfortran.h (gfc_resolve_atan2d, gfc_resolve_cotan,
	gfc_resolve_trigd, gfc_resolve_atrigd): New prototypes.
	* iresolve.c (resolve_trig_call, get_degrees, get_radians,
	is_trig_resolved, gfc_resolve_cotan, gfc_resolve_trigd,
	gfc_resolve_atrigd, gfc_resolve_atan2d): New functions.
	* intrinsics.h (gfc_simplify_atan2d, gfc_simplify_atrigd,
	gfc_simplify_cotan, gfc_simplify_trigd): New prototypes.
	* simplify.c (simplify_trig_call, degrees_f, radians_f,
	gfc_simplify_cotan, gfc_simplify_trigd, gfc_simplify_atrigd,
	gfc_simplify_atan2d): New functions.

	gcc/testsuite/gfortran.dg/
	* dec_math.f90: New testsuite.

From-SVN: r240989