golang/go

cmd/compile: intrinsify math/bits.RotateLeft{32,64} on all architectures

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#31,265 opened on Apr 4, 2019

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NeedsFixPerformancecompiler/runtimehelp wanted

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Description

https://github.com/golang/go/issues/21536#issuecomment-480003894 reminded me about this. Currently the intrinsic is only implemented on amd64, arm64, ppc64 and s390x. We should enable it everywhere. It will need tests in tests/codegen. Could be a good beginner compiler issue to tackle.

CLs so far:

Contributor guide

Research direction
Study the existing intrinsics for amd64, arm64, ppc64, s390x in the Go compiler source. Choose an architecture lacking support (e.g., 386, mips, etc.) and implement the intrinsic in the corresponding architecture's assembly or rewrite rules. Add a test in tests/codegen to verify the generated code. Follow the pattern from existing CLs.
Tech stack
go
Domain
compilers
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
GoGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80