add nvptx_target_feature and use unaligned barrier#1805
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jedbrown wants to merge 2 commits intorust-lang:mainfrom
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add nvptx_target_feature and use unaligned barrier#1805jedbrown wants to merge 2 commits intorust-lang:mainfrom
jedbrown wants to merge 2 commits intorust-lang:mainfrom
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This should now pass CI right ? |
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You'll need to rebase to re-run CI. |
* Deprecate _syncthreads (the CUDA name) in favor of new _barrier_sync (NVPTX name barrier.sync). * The: barrier.sync instruction is equivalent to barrier.sync.aligned prior to sm_70, and will lead to errors/deadlock if passes (such as MIR JumpThreading) lose the aligned property. rust-lang/rust#137086 https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#parallel-synchronization-and-communication-instructions-bar * Since: MIR does not currently have a way to apply something like LLVM's convergent attribute (and because convergent does not preserve alignment, which can be broken by inlining), we cannot prevent loss of alignment, and thus we require target feature sm_70. https://llvm.org/docs/ConvergentOperations.html
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Yeah, I can rebase. I'm having trouble finding docs for a development workflow for stdarch. The rustc josh docs describe making PRs to rust-lang/rust. I would like to build stdarch and use it with either |
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_syncthreads(the CUDA name) in favor of new_barrier_sync(NVPTX namebarrier.sync).barrier.syncinstruction is equivalent tobarrier.sync.alignedprior tosm_70, and will lead to errors/deadlock if passes (such as MIRJumpThreading) lose the aligned property.convergentattribute (and becauseconvergentdoes not preserve alignment, which can be broken by inlining), we cannot prevent loss of alignment, and thus we require target featuresm_70. In short, we cannot prevent miscompilation of aligned barriers without hard-to-specify preconditions.This requires rust-lang/rust#138689 (for
nvptx_target_feature) and fixes rust-lang/rust#137086.