[PATCH] D99432: [OPENMP]Fix PR48851: the locals are not globalized in SPMD mode.

Fri Mar 26 20:30:05 PDT 2021

jdoerfert added a comment.

In D99432#2653483 <https://reviews.llvm.org/D99432#2653483>, @ABataev wrote:

> In D99432#2653474 <https://reviews.llvm.org/D99432#2653474>, @jdoerfert wrote:
>
>> Can we please always do the globalization, even in the `target teams distribute parallel for` case you need it if a thread shares the address of a local variable with the team and another thread uses it.
>
> Could you give a small example so I could better understand the problem?

I didn't fine my old example, this should do though:
https://godbolt.org/z/En7To6xEW

On the host or host offload I see:
Mine: 0, Other: 42

On a GPU I see:
CUDA error: Error when synchronizing stream. stream = 0x000000004294db40, async info ptr = 0x00007fffdd939838
CUDA error: an illegal memory access was encountered

> Shall we globalize the variable in SPMD mode if we pass it by reference/take address in any case?

Yes. I think that is strictly speaking necessary. We should commit it together with the patches that "undo" globalization though.

>> There is no argument other than "doesn't escape" that Clang can make to disprove globalization is needed, IMHO.

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D99432