[Bug fortran/64416] New: RFE: Support REAL128 on arm

[Bug fortran/64416] New: RFE: Support REAL128 on arm

[orion at cora dot nwra.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64416

            Bug ID: 64416
           Summary: RFE: Support REAL128 on arm
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: orion at cora dot nwra.com

SUBROUTINE PMPI_Sizeof_complex128_scalar(x, size, ierror)
        USE, INTRINSIC :: iso_fortran_env, ONLY: REAL128
      COMPLEX(REAL128)::x
        INTEGER, INTENT(OUT) :: size
        INTEGER, INTENT(OUT) :: ierror

        size = storage_size(x) / 8
        ierror = 0
      END SUBROUTINE PMPI_Sizeof_complex128_scalar

gfortran -c psizeof_f.f90 
psizeof_f.f90:3.21:

      COMPLEX(REAL128)::x
                     1
Error: Kind -1 not supported for type COMPLEX at (1)

Linux fedora-rawhide-arm 3.18.1-2.fc22.armv7hl+lpae #1 SMP Fri Dec 19 00:19:30
UTC 2014 armv7l armv7l armv7l GNU/Linux

Is it possible to add support for this, or can the architecture not handle it?

[Bug fortran/64416] RFE: Support REAL128 on arm

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64416

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
The Procedure Call Standard for the ARM Architecture does not include a 
128-bit floating-point type, so if you want to support such a type in GCC 
for ARM you should first work with arm.eabi@arm.com to define the 
associated ABI and get a new version of AAPCS released.  Or you could use 
AArch64 - AAPCS64 does include such a type.

[Bug fortran/64416] RFE: Support REAL128 on arm

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64416

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |EH
             Target|                            |arm
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |WONTFIX

--- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
I suspect it's unlikely the EABI will be expanded in this direction; at least
until (unless) these types get implemented in hardware.

Furthermore, there's a high chance that if HW did implement 128-bit types, it
would be done in a way that was incompatible with any design choices we made
now, rendering a necessary ABI break or significant performance penalty.

My inclination is to close this as 'WONTFIX', with the understanding that if a
new ABI with such an extension does appear, support for it would be an
automatic step to implementing that ABI revision.