ARM64: Optimize pair of "str wzr, [reg]" to "str xzr" #35136

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1. Dotnet-GitSync-Bot commented on Apr 17, 2020

   

   Dotnet-GitSync-Bot

   on Apr 17, 2020

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   I couldn't figure out the best area label to add to this issue. Please help me learn by adding exactly one area label.
2. Dotnet-GitSync-Bot

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   untriagedNew issue has not been triaged by the area ownerNew issue has not been triaged by the area owner

   on Apr 17, 2020
3. kunalspathak

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   arch-arm64

   area-CodeGen-coreclrCLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMICLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI

   on Apr 17, 2020
4. BruceForstall commented on Apr 18, 2020

   

   BruceForstall

   on Apr 18, 2020

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   In addition, a sequence of 4 str wzr could be collapsed down to a single stp xzr, xzr by further optimizing using #35134.
5. BruceForstall commented on Apr 18, 2020

   

   BruceForstall

   on Apr 18, 2020

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   In the attached file, there are some interesting example that are more complicated than simple adjacency peephole optimization. E.g.,

   ; Assembly listing for method System.Data.ExpressionParser:StartScan():this
   [0024]        B9003C1F          str     wzr, [x0,#60]
   [0025]        B900301F          str     wzr, [x0,#48]
   [0026]        B900341F          str     wzr, [x0,#52]
   [0027]        B900401F          str     wzr, [x0,#64]
   

   Could be:

   str     xzr, [x0,#48]
   str     xzr, [x0,#60]
   

   but it require recognizing that the non-contiguous offsets 60 and 64 can be combined.
6. BruceForstall

   added this to the Future milestone on Apr 20, 2020
7. BruceForstall

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   untriagedNew issue has not been triaged by the area ownerNew issue has not been triaged by the area owner

   on Apr 20, 2020
8. BruceForstall

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   JitUntriagedCLR JIT issues needing additional triageCLR JIT issues needing additional triage

   on Oct 28, 2020
9. kunalspathak

   removed

   JitUntriagedCLR JIT issues needing additional triageCLR JIT issues needing additional triage

   on Nov 9, 2020
10. kunalspathak

    modified the milestones: Future, 6.0.0 on Nov 9, 2020
11. JulieLeeMSFT

    modified the milestones: 6.0.0, Future on Mar 23, 2021
12. ghost added

    in-prThere is an active PR which will close this issue when it is mergedThere is an active PR which will close this issue when it is merged

    on Apr 5, 2023
13. kunalspathak

    closed this as completedin #84350on Apr 6, 2023
14. ghost removed

    in-prThere is an active PR which will close this issue when it is mergedThere is an active PR which will close this issue when it is merged

    on Apr 6, 2023
15. ghost locked as resolved and limited conversation to collaborators on May 6, 2023
16. JulieLeeMSFT

    added this to .NET Core CodeGenon Jun 5, 2024
17. JulieLeeMSFT

    moved this to Done in .NET Core CodeGenon Jun 5, 2024