Re: Add 'libgomp.oacc-c-c++-common/private-atomic-1.c' [PR83812] (was: [PATCH][testsuite, nvptx] Add effective target sync_int_long_stack)

[Thomas Schwinge <thomas@codesourcery.com>]

Hi Tom!

On 2021-05-19T14:56:17+0200, I wrote:
> On 2020-08-12T15:57:23+0200, Tom de Vries <tdevries@suse.de> wrote:
>> When enabling sync_int_long for nvptx, we run into a failure in
>> gcc.dg/pr86314.c:
>> ...
>>  nvptx-run: error getting kernel result: operation not supported on \
>>    global/shared address space
>> ...
>> due to a ptx restriction:  accesses to local memory are illegal, and the
>> test-case does an atomic operation on a stack address, which is mapped to
>> local memory.
>
> Now, that problem also is easy to reproduce in an OpenACC/nvptx
> offloading setting.  (..., as Julian had reported and analyzed in an
> internal "Date: Fri, 31 May 2019 00:29:17 +0100" email, similar to Tom's
> comments in PR96494 "[nvptx] Enable effective target sync_int_long" and
> PR97444 "[nvptx] stack atomics".)
>
>> Fix this by adding a target sync_int_long_stack, wich returns false for nvptx,
>> which can be used to mark test-cases that require sync_int_long support for
>> stack address.

Shouldn't this now again be reverted/removed after your
commit e0451f93d9faa13495132f4e246e9bef30b51417
"[nvptx] Add some support for .local atomics"?
(But I haven't looked in detail.)


Is PR83812 "nvptx-run: error getting kernel result: operation not
supported on global/shared address space" resolved then?

Or, because of:

| This only solves some cases that are detected at compile-time.

... not completely resolved?

There's also still PR97444 "[nvptx] stack atomics" open.


> Similar to PR97444 "[nvptx] stack atomics", such a conditional is of
> course not applicable for the OpenACC implementation, so to at least
> document/test/XFAIL nvptx offloading: PR83812 "operation not supported
> on global/shared address space", I've now pushed to master branch
> "Add 'libgomp.oacc-c-c++-common/private-atomic-1.c' [PR83812]" in
> commit 1467100fc72562a59f70cdd4e05f6c810d1fadcc, see attached.

... which later got replicated in other test cases --
all of which I confirm are resolved and un-XFAILed with
commit e0451f93d9faa13495132f4e246e9bef30b51417
"[nvptx] Add some support for .local atomics".


> And then, I got back testresults from one more system, and I've filed
> <https://gcc.gnu.org/PR100678> "[OpenACC/nvptx]
> 'libgomp.oacc-c-c++-common/private-atomic-1.c' FAILs (differently) in
> certain configurations"...  :-\

..., and that I also confirm to be resolved with
commit e0451f93d9faa13495132f4e246e9bef30b51417
"[nvptx] Add some support for .local atomics".


Grüße
 Thomas
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