rust-lang / rust-lang/rust

possible AMDGPU alignment bug

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A-LLVM C-bug O-amdgcn T-compiler
Dominant language
Rust
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Description

See https://github.com/nikic/llvm-project/blob/e0b1d80e09a1818e9ef2da76ca2e928dfe92c0a7/clang/lib/CodeGen/CodeGenModule.cpp

There is a possible bug in how we handle alignment on AMDGPU targets for i128. This is most likely to cause problems with linked code across languages. I am opening this issue for tracking reasons.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with clang/lib/CodeGen/CodeGenModule.cpp at the referenced revision and investigate how alignment for i128 is handled on AMDGPU targets. Compare the behavior with Rust's compiler handling and linked cross-language code; the issue does not define an expected result, so completion requires establishing the correct alignment and a regression test.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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