rust-lang / rust-lang/rustc_codegen_cranelift

Math operations for f16 incorrectly implemented

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C-bug
Dominant language
Rust
Stars
2.1k
Forks
157
Avg merge
1d 19h
Merged PRs (30d)
3

Description

libm has no such intrinsics as logf16 and roundf16. Discovered in https://github.com/rust-lang/rust/pull/148206#issuecomment-3728270321.

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 by tracing how f16 math operations are lowered in the rustc_codegen_cranelift repository, using the referenced Rust pull request and issue comment as context. Check the handling of log and round operations and identify the valid libm alternatives; done means the backend no longer refers to nonexistent logf16 or roundf16 intrinsics.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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