[Bug fortran/109322] -fc-prototypes does not correctly translate INTEGER(KIND=C_SIZE_T), and other sizes

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109322

--- Comment #9 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Wed, Mar 29, 2023 at 07:42:08PM +0000, sgk at troutmask dot
apl.washington.edu wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109322
> 
> --- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
> On Wed, Mar 29, 2023 at 05:50:05PM +0000, emr-gnu at hev dot psu.edu wrote:
> > 
> > 
> > Extending my original demonstrator, if you add a "INTEGER(KIND=C_INT64_T) ::
> > E", you get the following output:
> > 
> > > gfortran -m32 -fc-prototypes -fsyntax-only foo.f90
> > 
> >  long a;
> >  {...}
> >  long_long e;
> > } bar;
> 
> The companion C processor is gcc.  It is generating
> prototypes for that C processor.  If one is manipulating
> the environment with a command line option such as -m32
> or -m64, then one likely needs to use the same option 
> with gcc.  Does 'gcc -m32' support "long_long"?  If it
> doesn't, then you'll need to hack on 
> 
> gcc/fortran/dump-parse-tree.cc
> gcc/fortran/iso-c-binding.def
> gcc/fortran/trans-types.cc

If one instruments, write_decl() in dump-parse-tree.cc to
dump the table of bind(c) types, one can see why you get
what you get.

% cat a.f90
module foo
 use, intrinsic :: iso_c_binding
 implicit none
 public :: bar
 type, bind(c) :: bar
  integer(c_int64_t) a
 end type
end module

% gfcx -fc-prototypes -fsyntax-only a.f90 | grep "value=8 IN"
  2 value=8 INTEGER c_long
  3 value=8 INTEGER c_long_long
  4 value=8 INTEGER c_intmax_t
  5 value=8 INTEGER c_intptr_t
  6 value=8 INTEGER c_ptrdiff_t
  7 value=8 INTEGER c_size_t
 12 value=8 INTEGER c_int64_t
 17 value=8 INTEGER c_int_least64_t
 22 value=8 INTEGER c_int_fast64_t

typedef struct bar {
    long a;
} bar;

The for-loop in write_decl() breaks on the first match to
to both value=8 and INTEGER.  It never reaches the 12th
table entry for c_int64_t.