Fortran: overloading of intrinsic binary operators [PR109641]

Fortran: overloading of intrinsic binary operators [PR109641]

Fortran allows overloading of intrinsic operators also for operands of
numeric intrinsic types.  The intrinsic operator versions are used
according to the rules of F2018 table 10.2 and imply type conversion as
long as the operand ranks are conformable.  Otherwise no type conversion
shall be performed to allow the resolution of a matching user-defined
operator.

gcc/fortran/ChangeLog:

	PR fortran/109641
	* arith.cc (eval_intrinsic): Check conformability of ranks of operands
	for intrinsic binary operators before performing type conversions.
	* gfortran.h (gfc_op_rank_conformable): Add prototype.
	* resolve.cc (resolve_operator): Check conformability of ranks of
	operands for intrinsic binary operators before performing type
	conversions.
	(gfc_op_rank_conformable): New helper function to compare ranks of
	operands of binary operator.

gcc/testsuite/ChangeLog:

	PR fortran/109641
	* gfortran.dg/overload_5.f90: New test.