http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53667
--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-07 09:01:10 UTC --- Ok, so fixing this will pessimize gfortran.dg/c_ptr_tests_16.f90 as print '(z8)', a will now clobber a even though we have _gfortran_transfer_integer_write (&dt_parm.1, &a, 8); marked with ".wR" (that is, &a is specified as to not escape and not be clobbered). Still, as &dt_parm.1 is clobbered it possibly gets assigned &a and by means of being clobbered it will clobber &a ... Not sure if we can restrict non-escaping to also not escape to other parameters? Possibly we should, otherwise this property won't be very useful.
