dotnet/runtime

Support recognizing `Blend` as commutative

Open

#82,365 opened on Feb 19, 2023

View on GitHub
 (5 comments) (2 reactions) (2 assignees)C# (5,445 forks)batch import
area-CodeGen-coreclrhelp wanted

Repository metrics

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

Description

We don't currently track Blend as commutative and so we miss an opportunity to ensure that "memory operands" always appear on the RHS: https://github.com/SixLabors/ImageSharp/pull/2359#discussion_r1111147888

Support should be added to treat this as commutative which really just entails inverting the constant (e.g. Blend(x, y, 0b0111_0111) is equivalent to Blend(y, x, 0b1000_1000)).

There are actually a few operations this applies to that involve two inputs + control mask. Not all of them are as trivially as inverting the constant, however.

Contributor guide

Research direction
Examine how commutativity is handled for other operations in the codebase, then implement similar logic for Blend by inverting the constant mask.
Tech stack
csharp
Domain
backend
Issue type
Feature
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#
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75