dotnet/runtime

Updating the RMW flags for HWIntrinsic nodes

Open

#9,907 opened on Mar 9, 2018

View on GitHub
 (3 comments) (0 reactions) (0 assignees)C# (5,445 forks)batch import
area-CodeGen-coreclrenhancementhelp wanted

Repository metrics

Stars
 (17,886 stars)
PR merge metrics
 (Avg merge 12d 11h) (661 merged PRs in 30d)

Description

At present, RMW semantics is tracked via a combination of the compiler support for VEX-encoded instructions and the NoRMWSemantics flag.

We should update this to instead be a combination of flags: RMWSemanticsSseOnly and RMWSemanticsAlways (or similar).

This will allow all scenarios to be table driven and for the check to be a positive case, rather than a negative case (which can sometimes lead to confusion).

category:implementation theme:hardware-intrinsics skill-level:intermediate cost:small

Contributor guide

Research direction
Examine the current RMW semantics tracking using VEX encoded instruction support and NoRMWSemantics flag. Understand HWIntrinsic nodes and propose a table driven approach with positive flags like RMWSemanticsSseOnly and RMWSemanticsAlways.
Tech stack
csharp
Domain
backendcompilers
Issue type
Refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60