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Evaluate JIT_MemCpy without overlap check #6701

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helloguo opened this issue Sep 21, 2016 · 3 comments
Open

Evaluate JIT_MemCpy without overlap check #6701

helloguo opened this issue Sep 21, 2016 · 3 comments
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area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI enhancement Product code improvement that does NOT require public API changes/additions tenet-performance Performance related issue
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Future

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@helloguo
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The current implementation of JIT_MemCpy on x64 Windows checks for address overlap and different paths are taken depending on result. However, ECMA-335 mentions "The behavior of cpblk is unspecified if the source and destination areas overlap". An optimized version without overlap check may be worth evaluating and implementing. dotnet/coreclr#7198

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@msftgits msftgits transferred this issue from dotnet/coreclr Jan 31, 2020
@msftgits msftgits added this to the Future milestone Jan 31, 2020
@BruceForstall BruceForstall added the JitUntriaged CLR JIT issues needing additional triage label Oct 28, 2020
@TIHan
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TIHan commented Nov 1, 2023

Comment regarding the overlapping buffers:

        ; Use memmove to handle overlapping buffers for better
        ; compatibility with .NET Framework. Needing to handle
        ; overlapping buffers in cpblk is undefined by the spec.

It might be worth evaluating? Hard to tell, but keeping this as future.

@TIHan TIHan removed the JitUntriaged CLR JIT issues needing additional triage label Nov 1, 2023
@TIHan TIHan mentioned this issue Nov 1, 2023
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@EgorBo
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EgorBo commented Mar 16, 2024

Closed by #98623

@EgorBo EgorBo closed this as completed Mar 16, 2024
@EgorBo
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EgorBo commented Mar 16, 2024

Ah, sorry, it's a different issue. Although, I don't think we'll remove the overlap check

@EgorBo EgorBo reopened this Mar 16, 2024
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area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI enhancement Product code improvement that does NOT require public API changes/additions tenet-performance Performance related issue
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@EgorBo @TIHan @msftgits @BruceForstall @helloguo