re PR fortran/90903 (Implement runtime checks for bit manipulation intrinsics)

re PR fortran/90903 (Implement runtime checks for bit manipulation intrinsics)

2019-07-16  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/90903
	* libgfortran.h: Add mask for -fcheck=bits option.
	* options.c (gfc_handle_runtime_check_option): Add option "bits"
	to run-time checks selectable via -fcheck.
	* trans-intrinsic.c (gfc_conv_intrinsic_btest)
	(gfc_conv_intrinsic_singlebitop, gfc_conv_intrinsic_ibits)
	(gfc_conv_intrinsic_shift, gfc_conv_intrinsic_ishft)
	(gfc_conv_intrinsic_ishftc): Implement run-time checks for the
	POS, LEN, SHIFT, and SIZE arguments.
	* gfortran.texi: Document run-time checks for bit manipulation
	intrinsics.
	* invoke.texi: Document new -fcheck=bits option.

	PR fortran/90903
	* gfortran.dg/check_bits_1.f90: New testcase.

From-SVN: r273535