[Bug target/105421] New: GCN offloading, raised '-mgang-private-size': 'HSA_STATUS_ERROR_MEMORY_APERTURE_VIOLATION'

["tschwinge at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105421

            Bug ID: 105421
           Summary: GCN offloading, raised '-mgang-private-size':
                    'HSA_STATUS_ERROR_MEMORY_APERTURE_VIOLATION'
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: ams at gcc dot gnu.org, jules at gcc dot gnu.org
  Target Milestone: ---
            Target: GCN

As discussed in
<http://mid.mail-archive.com/87fslzspgo.fsf@dem-tschwing-1.ger.mentorg.com>,
after commit r12-8252-gb2202431910e30d8505c94d1cb9341cac7080d10 "fortran: Fix
up gfc_trans_oacc_construct [PR104717]", we need commit
r12-8311-g2a570f11a2fecf23998d7fe1d5cabad62cfe5cec "Fix up
'libgomp.oacc-fortran/print-1.f90' GCN offloading compilation [PR104717]",
however:

> That only works with the default GCN multilib '-march=fiji', testing
> on gfx803 amdfury2 system.  For all of '-march=gfx900' (amdnano2),
> '-march=gfx906' (amd_ryzen3), '-march=gfx908' (amd-instinct1), I get:
> 
>     libgomp: GCN fatal error: Asynchronous queue error
>     Runtime message: HSA_STATUS_ERROR_MEMORY_APERTURE_VIOLATION: The agent attempted to access memory beyond the largest legal address.
> 
> ..., and I still get that if lowering the allocation to the minimum,
> '-foffload-options=amdgcn-amdhsa=-mgang-private-size=560'.
> 
> This is a really simple OpenACC 'parallel' construct:
> 
>     !$acc parallel
>       write (0, '("The answer is ", I2)') var
>     !$acc end parallel
> 
> ..., which ought to launch a 1-gang x 1-worker x 1-vector GPU kernel, so
> I'd assume '-mgang-private-size=560' (or '-mgang-private-size=13579' in
> fact) is not a problem?