A few fixes for compiling with nvc++ #14139
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The previous code causes a linker failure due to a duplicated definition of `PointerLikeTypeTraits<decltype(PointerUnion<PTs...>::Val)>::NumLowBitsAvailable`.
bernhardmgruber
requested review from
bellenot,
vgvassilev and
Axel-Naumann
as code owners
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Can one of the admins verify this patch? |
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@phsft-bot build |
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Starting build on |
| @@ -261,8 +261,9 @@ struct PointerLikeTypeTraits<PointerUnion<PTs...>> { | |||
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| // The number of bits available are the min of the pointer types minus the | |||
| // bits needed for the discriminator. | |||
| static constexpr int NumLowBitsAvailable = PointerLikeTypeTraits<decltype( | |||
| PointerUnion<PTs...>::Val)>::NumLowBitsAvailable; | |||
| using nvhpcWorkAround = decltype(PointerUnion<PTs...>::Val); | |||
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Is this patch a backport of the llvm upstream?
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No, LLVM upstream (17.0.6) does not have this change and nvc++ fails equally there. What is the procedure to apply such a workaround to ROOT's LLVM?
(while NVIDIA may be working on a fix to nvc++)
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I think it should be enough if we open a PR against LLVM mainline and backport it here. It'd be better to wait until it gets merged upstream but generally there is no need to.
cc: @hahnjo
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Either way, I'm not a fan of introducing a workaround to our copy of LLVM for a very specific compiler. I believe upstream has a very clear documentation on which compilers it supports, and NVIDIA's isn't one of them. It's not our job to fix this downstream.
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Alright, this gets more tricky than anticipated. I had to workaround a few more codegen/optimizer bugs in nvc++. I changed the PR to draft for now. |
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I propose to close this: As I expressed above, I believe it's not our job to fix upstream LLVM to compile with |
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Fine for me, I will open a separate PR with the reasonable changes. |
This Pull request:
Changes or fixes:
Fixes several issues when compiling ROOT with nvc++, but not all of them. The build still fails ultimately, because
clang-tblgencrashes. See also #9036.Checklist: