> I don't know enough about Fortran to know whether the same issues arise
> there.  Perhaps in Fortran a common symbol is always a common symbol and
> can never be a defined symbol.  If that is the case then for Fortran I
> think it would be safe to change the alignment of the common symbol.  Of
> course we would need to have some way to indicate that in the
> middle-end--DECL_ALWAYS_COMMON or something.

I don't know if this answers the question, but I have run the gfortran 
test suite with -fno-common and I have seen only one failure:

[macbook] lin/test% gfc 
-fno-common -save-temps
ld: duplicate symbol _i in global_vars_f90_init_driver.o and 
collect2: error: ld returned 1 exit status

AFAICT, COMMON is only lightly tested in the gfortran test suite and mostly
for errors or warnings.  However I find surprising that
gfortran.dg/bind_c_coms.f90 + gfortran.dg/bind_c_coms_driver.c works:

[macbook] lin/test% gfc /opt/gcc/work/gcc/testsuite/gfortran.dg/bind_c_coms.f90 
/opt/gcc/work/gcc/testsuite/gfortran.dg/bind_c_coms_driver.c -fno-common
[macbook] lin/test% a.out 
[macbook] lin/test% 


Reply via email to