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Scalar vector operations can use NEON instructions, which have incorrect subnormal behavior #129853

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RalfJung opened this issue Sep 1, 2024 · 0 comments
Open

Scalar vector operations can use NEON instructions, which have incorrect subnormal behavior #129853

RalfJung opened this issue Sep 1, 2024 · 0 comments
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A-floating-point Area: Floating point numbers and arithmetic A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. C-bug Category: This is a bug. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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RalfJung commented Sep 1, 2024

This is the Rust version of llvm/llvm-project#106909: scalar f32/f64 operations can produce the wrong result for subnormals on ARM if NEON instructions are used.

This just got fixed in upstream LLVM, but we should also have a test covering this.

Cc @nikic
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Sep 1, 2024
@RalfJung RalfJung added A-floating-point Area: Floating point numbers and arithmetic A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. labels Sep 1, 2024
@saethlin saethlin added T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-bug Category: This is a bug. and removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. labels Sep 2, 2024
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A-floating-point Area: Floating point numbers and arithmetic A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. C-bug Category: This is a bug. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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