PR fortran/48979

	* trans-const.c (gfc_build_nan): New function.
	* trans-const.h (gfc_build_nan): New prototype.
	* trans-intrinsic.c (gfc_conv_intrinsic_exponent): Handle special
	values.
	(gfc_conv_intrinsic_minmaxval): Use gfc_build_nan.
	(gfc_conv_intrinsic_fraction): Handle special values.
	(gfc_conv_intrinsic_spacing): Likewise.
	(gfc_conv_intrinsic_rrspacing): Likewise.
	(gfc_conv_intrinsic_set_exponent): Likewise.

	* gfortran.dg/ieee/intrinsics_2.F90: New test.

From-SVN: r216443