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@a74nh a74nh commented Jan 27, 2026

Fixes #123496

Copilot AI review requested due to automatic review settings January 27, 2026 12:19
@github-actions github-actions bot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Jan 27, 2026
@dotnet-policy-service dotnet-policy-service bot added the community-contribution Indicates that the PR has been added by a community member label Jan 27, 2026
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Pull request overview

This PR fixes an issue with SVE (Scalable Vector Extension) long narrowing operations for shift instructions by renaming and correcting the behavior of a SIMD narrowing function.

Changes:

  • Renamed NarrowSimdLong to NarrowAndDuplicateSimdLong to accurately reflect its behavior of narrowing and duplicating elements
  • Fixed the element count calculation to use sizeof(TBase) instead of sizeof(uint64_t), which corrects the narrowing operation for shifts
  • Updated all call sites to use the renamed function

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File Description
src/coreclr/jit/simd.h Renamed function and fixed count calculation; added comprehensive XML documentation
src/coreclr/jit/valuenum.cpp Updated function call to use renamed function
src/coreclr/jit/gentree.cpp Updated function call to use renamed function

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a74nh commented Jan 27, 2026

@dotnet/arm64-contrib

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a74nh commented Jan 28, 2026

SPMI issues look unrelated to this PR.

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JIT: Bad result with Sve.ShiftLeftLogical

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