https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96428
Thomas Schwinge <tschwinge at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|RESOLVED |REOPENED
Resolution|FIXED |---
CC| |tschwinge at gcc dot gnu.org
Last reconfirmed| |2020-10-01
--- Comment #7 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
First: Tobias, Tom, thanks for fixing this issue!
(In reply to Tobias Burnus from comment #3)
> Created attachment 48988 [details]
> Test case (as diff – two files)
These attachment 48988 testcases got included in commit
344f09a756ebd50510cc1eb3db111fd61c527702. I don't understand
'libgomp.oacc-fortran/pr96628-part1.f90':
module m2
real*8 :: mysum
!$acc declare device_resident(mysum)
So 'mysum' lives in device-global memory.
contains
SUBROUTINE one(t)
!$acc routine
REAL*8, INTENT(IN) :: t(:)
mysum = sum(t)
END SUBROUTINE one
This now writes into device-global 'mysum', potentially from several
gang/worker/vector threads in parallel, race condition?
SUBROUTINE two(t)
!$acc routine seq
REAL*8, INTENT(INOUT) :: t(:)
t = (100.0_8*t)/sum
END SUBROUTINE two
end module m2
source-gcc/libgomp/testsuite/libgomp.oacc-fortran/pr96628-part1.f90: In
function ‘__m2_MOD_two’:
source-gcc/libgomp/testsuite/libgomp.oacc-fortran/pr96628-part1.f90:18:
warning: ‘sum’ is used uninitialized [-Wuninitialized]
18 | t = (100.0_8*t)/sum
So, is this really testing what it means to be testing?
Should the testcase get some 'target openacc_nvidia_accel_selected'
'scan-offload-rtl-dump' added to make sure that we're actually generating the
expected PTX instructions?
Also, the testcase files should be renamed 'libgomp.oacc-fortran/pr96428-*' to
match the PR ID.
(In reply to Tom de Vries from comment #4)
> FTR, this is not the leanest solution.
> followup patch: [...]
> we have instead: [simpler]
Any plans to apply that as a follow-up?
