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* [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
@ 2021-11-23 14:27 burnus at gcc dot gnu.org
  2021-11-23 14:59 ` [Bug middle-end/103384] " jakub at gcc dot gnu.org
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: burnus at gcc dot gnu.org @ 2021-11-23 14:27 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

            Bug ID: 103384
           Summary: [OpenMP] declare variant with device={kind(nohost)}
                    does not use GPU, kind(gpu) works
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: openmp, wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
                CC: jakub at gcc dot gnu.org
  Target Milestone: ---

Created attachment 51861
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51861&action=edit
Testcase, fails as is (if omp_get_num_devices() > 0) and '{kind(nohost)}' -
works when later is changed to "match(device={kind(gpu)})"

Observed with
https://github.com/SOLLVE/sollve_vv/blob/master/tests/5.0/declare_target/test_declare_target_device_type_nohost.c

For that testcase with nvptx offloading, with

  #pragma omp declare variant(target_function) match(device={kind(gpu)})

target_function() is called and the code is executed on the GPU
(value a[0] = 5 (host function 'update') + 1 (device function
'target_function') == 6).


However, using kind(nohost), i.e.

  #pragma omp declare variant(target_function) match(device={kind(nohost)})

will *not* execute 'target_function' (thus: a[0] == 10 = 2*5 (host function
'update').


Expected: both {kind(nohost)} and {kind(gpu)} are executed on the GPU.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug middle-end/103384] [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
  2021-11-23 14:27 [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works burnus at gcc dot gnu.org
@ 2021-11-23 14:59 ` jakub at gcc dot gnu.org
  2021-11-24  9:35 ` cvs-commit at gcc dot gnu.org
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-11-23 14:59 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Would
--- gcc/omp-general.c.jj        2021-10-15 11:59:16.135683948 +0200
+++ gcc/omp-general.c   2021-11-23 15:45:32.761468592 +0100
@@ -1487,16 +1487,22 @@ omp_context_selector_matches (tree ctx)
                      continue;
                    if (!strcmp (prop, "host"))
                      {
+#ifdef ACCEL_COMPILER
+                       return 0;
+#else
                        if (omp_maybe_offloaded ())
                          ret = -1;
                        continue;
+#endif
                      }
                    if (!strcmp (prop, "nohost"))
                      {
+#ifndef ACCEL_COMPILER
                        if (omp_maybe_offloaded ())
                          ret = -1;
                        else
                          return 0;
+#endif
                        continue;
                      }
                    int r = 0;
fix this?  In ACCEL_COMPILER we know that it is nohost, so for host we should
return 0 even if we earlier on the host side said it might be offloaded and so
defer, and for host we know it is ok.

I don't really like the test, in the SOLLVE test it just relies on no host
fallback without ensuring it, in your attached test omp_get_num_devices ()
doesn't guarantee no host fallback either.  Check omp_is_initial_device () in
the target region instead?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug middle-end/103384] [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
  2021-11-23 14:27 [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works burnus at gcc dot gnu.org
  2021-11-23 14:59 ` [Bug middle-end/103384] " jakub at gcc dot gnu.org
@ 2021-11-24  9:35 ` cvs-commit at gcc dot gnu.org
  2021-11-24 10:00 ` jakub at gcc dot gnu.org
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-11-24  9:35 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:5bca26742cf3357bf4e20ec97eee4c7f7de17ce0

commit r12-5494-g5bca26742cf3357bf4e20ec97eee4c7f7de17ce0
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 24 10:30:32 2021 +0100

    openmp: Fix up handling of kind(host) and kind(nohost) in ACCEL_COMPILERs
[PR103384]

    As the testcase shows, we weren't handling kind(host) and kind(nohost)
properly
    in the ACCEL_COMPILERs, the code written in there is valid for the host
    compiler only, where if we are maybe offloaded, we defer resolution after
IPA,
    otherwise return 0 for kind(nohost) and accept it for kind(host).  Note,
    omp_maybe_offloaded is false after IPA.  If ACCEL_COMPILER is defined, it
is
    the other way around, but also we know we are after IPA.

    2021-11-24  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/103384
    gcc/
            * omp-general.c (omp_context_selector_matches): For ACCEL_COMPILER,
            return 0 for kind(host) and continue for kind(nohost).
    libgomp/
            * testsuite/libgomp.c/declare-variant-2.c: New test.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug middle-end/103384] [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
  2021-11-23 14:27 [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works burnus at gcc dot gnu.org
  2021-11-23 14:59 ` [Bug middle-end/103384] " jakub at gcc dot gnu.org
  2021-11-24  9:35 ` cvs-commit at gcc dot gnu.org
@ 2021-11-24 10:00 ` jakub at gcc dot gnu.org
  2021-11-29  8:50 ` cvs-commit at gcc dot gnu.org
  2022-05-10  8:22 ` cvs-commit at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-11-24 10:00 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug middle-end/103384] [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
  2021-11-23 14:27 [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works burnus at gcc dot gnu.org
                   ` (2 preceding siblings ...)
  2021-11-24 10:00 ` jakub at gcc dot gnu.org
@ 2021-11-29  8:50 ` cvs-commit at gcc dot gnu.org
  2022-05-10  8:22 ` cvs-commit at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-11-29  8:50 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:333b0dc1792f48e822ebaaea6e104539918f47f2

commit r11-9338-g333b0dc1792f48e822ebaaea6e104539918f47f2
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 24 10:30:32 2021 +0100

    openmp: Fix up handling of kind(host) and kind(nohost) in ACCEL_COMPILERs
[PR103384]

    As the testcase shows, we weren't handling kind(host) and kind(nohost)
properly
    in the ACCEL_COMPILERs, the code written in there is valid for the host
    compiler only, where if we are maybe offloaded, we defer resolution after
IPA,
    otherwise return 0 for kind(nohost) and accept it for kind(host).  Note,
    omp_maybe_offloaded is false after IPA.  If ACCEL_COMPILER is defined, it
is
    the other way around, but also we know we are after IPA.

    2021-11-24  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/103384
    gcc/
            * omp-general.c (omp_context_selector_matches): For ACCEL_COMPILER,
            return 0 for kind(host) and continue for kind(nohost).
    libgomp/
            * testsuite/libgomp.c/declare-variant-2.c: New test.

    (cherry picked from commit 5bca26742cf3357bf4e20ec97eee4c7f7de17ce0)

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug middle-end/103384] [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works
  2021-11-23 14:27 [Bug middle-end/103384] New: [OpenMP] declare variant with device={kind(nohost)} does not use GPU, kind(gpu) works burnus at gcc dot gnu.org
                   ` (3 preceding siblings ...)
  2021-11-29  8:50 ` cvs-commit at gcc dot gnu.org
@ 2022-05-10  8:22 ` cvs-commit at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-10  8:22 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103384

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:279e48e9d8e8d99a73d5ca69f829b83638419c56

commit r10-10658-g279e48e9d8e8d99a73d5ca69f829b83638419c56
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 24 10:30:32 2021 +0100

    openmp: Fix up handling of kind(host) and kind(nohost) in ACCEL_COMPILERs
[PR103384]

    As the testcase shows, we weren't handling kind(host) and kind(nohost)
properly
    in the ACCEL_COMPILERs, the code written in there is valid for the host
    compiler only, where if we are maybe offloaded, we defer resolution after
IPA,
    otherwise return 0 for kind(nohost) and accept it for kind(host).  Note,
    omp_maybe_offloaded is false after IPA.  If ACCEL_COMPILER is defined, it
is
    the other way around, but also we know we are after IPA.

    2021-11-24  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/103384
    gcc/
            * omp-general.c (omp_context_selector_matches): For ACCEL_COMPILER,
            return 0 for kind(host) and continue for kind(nohost).
    libgomp/
            * testsuite/libgomp.c/declare-variant-2.c: New test.

    (cherry picked from commit 5bca26742cf3357bf4e20ec97eee4c7f7de17ce0)

^ permalink raw reply	[flat|nested] 6+ messages in thread

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