Fortran: improve bounds-checking for array sections [PR30802]

Fortran: improve bounds-checking for array sections [PR30802]

gcc/fortran/ChangeLog:

	PR fortran/30802
	* trans-array.cc (trans_array_bound_check): Add optional argument
	COMPNAME for explicit specification of array component name.
	(array_bound_check_elemental): Helper function for generating
	bounds-checking code for elemental dimensions.
	(gfc_conv_expr_descriptor): Use bounds-checking also for elemental
	dimensions, i.e. those not handled by the scalarizer.

gcc/testsuite/ChangeLog:

	PR fortran/30802
	* gfortran.dg/bounds_check_fail_6.f90: New test.