dotnet/runtime

RyuJIT/x86: REGMASK_BITS should be 16 for x86, not 32

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#7,575 opened on Mar 8, 2017

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 (10 comments) (0 reactions) (0 assignees)C# (17,886 stars) (5,445 forks)batch import
HackathonJitThroughputarch-x86area-CodeGen-coreclrenhancementgood first issuetenet-performance

Description

regMaskSmall can be 16 bits, not 32, for RyuJIT/x86.

category:throughput theme:ir skill-level:intermediate cost:small

Contributor guide

Tech stack
csharp
Domain
performancebackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
x86 register masksRyuJIT internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Examine the RyuJIT source code in the dotnet/runtime repository, focusing on the definition and usage of REGMASK BITS. Identify where regMaskSmall is used and confirm that for x86 targets it should be 16 bits instead of 32. Review the issue comments for any additional context or proposed changes. No pull requests are linked, so implement the fix by modifying the relevant files.