[Bug libfortran/71363] Issue when sizeof(double) = sizeof(long double)

[jvdelisle at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71363

Jerry DeLisle <jvdelisle at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jvdelisle at gcc dot gnu.org

--- Comment #2 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
(In reply to Paul Mustiere from comment #0)
> Hello,
> 
> I am building the GNU toolchain for Android with support for Fortran, and
> encountered an issue when targeting x86 for the runtime library.
> 
> Note: I'm using the toolchain sources provided by Google, but as far as I
> can tell the Fortran part is simply 4.9 since they are not trying to build
> with Fortran.
> 
> In intrisics/cshift0.c, I get a 'duplicate case value'
> (http://paste.ubuntu.com/16861425/). As far as I can tell:
> 
> - GFC_DTYPE_REAL_16 is defined (but not GFC_DTYPE_REAL_10), hence
> GFC_REAL_16 is defined as long double.
> - sizeof(long double) = sizeof(double) = 8, which causes the duplicate case.
> 
> I find a workaround which consists of detecting both sizes in mk-kinds-h.sh
> and checking that they are not equal before defining GFC_REAL_16. The rest
> of the toolchain compiles fine, but I am not sure it's ideal.
> Also, I'm curious as to why Fortran seems to be fine with real (kind=16) but
> C doesn't seem to be able to hold variables that big.
> 
> I know I'm not using the regular GNU toolchain but any help is appreciated.
> 
> Cheers,
> Paul Mustiere

Paul,

Look for where "for k in $possible_real_kinds" is in the mk-kinds script. Where
is $possible_real_kinds set?