rust-lang / rust-lang/rustc_codegen_gcc

Use -mcpu on Aarch64

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libgccjit
Dominant language
Rust
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Merged PRs (30d)
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Description

On some Aarch64 CPUs (like the dev desktops), host_detect_local_cpu with params[] = { "arch" } returns NULL whereas host_detect_local_cpu with params[] = { "cpu" } returns a value.

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  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 the linked gcc/config/aarch64/aarch64-jit.cc implementation of host_detect_local_cpu and compare the "arch" and "cpu" parameter behavior on Aarch64. Trace how the codegen path uses that result, then verify that local CPU detection uses -mcpu and works on the affected dev desktops.

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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