build: Update C++ standard from c++17 to c++20 - #8962
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September 10, 2026 18:20
Upstream PyTorch raised ATen's minimum required C++ standard from 17 to 20 (pytorch/pytorch#178150), which broke the pytorch_backend build. Align this repo's TRITON_MIN_CXX_STANDARD/CMAKE_CXX_STANDARD default with that floor for consistency across the stack. TRI-1877
These QA smoke tests compile a downstream consumer app directly with plain g++ against the packaged triton_client headers/libs, with no -std= flag -- so they defaulted to GCC 13's gnu++17. Since the C++20 bump (TRI-1877) now builds the packaged client's grpc/protobuf/abseil dependencies at C++20, their exported headers expect C++20 (e.g. std::partial_ordering/strong_ordering aliases in absl/types/compare.h), which a gnu++17 compile can't satisfy: "'partial_ordering' has not been declared in 'std'". Pass -std=gnu++20 to match. TRI-1877
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What does the PR do?
mchornyi/TRI-1855/build-against-upstream(unrelated upstream-container work, tracked separately) — PR base is set to that branch so this diff shows only the C++20 change.Checklist
<commit_type>: <Title>Commit Type:
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Where should the reviewer start?
CMakeLists.txtTest plan:
Caveats:
This repo has no direct dependency on ATen/libtorch; the bump is for cross-repo C++ standard consistency, not a confirmed build break here.
Background
Part of a coordinated C++17->C++20 bump across ~18 Triton component repos (TRI-1877), triggered by upstream PyTorch's ATen.h now requiring C++20.
Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)