Fortran: Implement the COSHAPE intrinsic [PR99250]

2026-02-13  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/99250
	* check.cc (gfc_check_coshape): New function.
	* gfortran.h: Add GFC_ISYM_COSHAPE to gfc_isym_id.
	* intrinsic.cc (add_functions): Add the coshape prototype and
	its 'make_generic'.
	* intrinsic.h: Add prototypes for gfc_check_coshape and
	gfc_resolve_coshape.
	* intrinsic.texi : Add entries for coshape.
	* iresolve.cc (gfc_resolve_coshape): New function.
	* trans-array.cc (gfc_conv_ss_startstride): Add 'case
	GFC_ISYM_COSHAPE' in two places.
	* trans-intrinsic.cc (conv_intrinsic_cobound): Modify assert in
	scalarized section for lbound. Set bound to zero for scalar
	case of coshape. Keep the lbound and use it together with the
	scalarized ubound to obtain the coshape.
	(gfc_conv_intrinsic_function, gfc_add_intrinsic_ss_code and
	gfc_walk_intrinsic_function): Add 'case GFC_ISYM_COSHAPE' as
	appropriate.

gcc/testsuite/
	PR fortran/99250
	* gfortran.dg/coshape_1.f90: New test.