llvm/llvm-project

[X86] Add ComputeKnownBits support for BEXTR

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#38,501 opened on Oct 2, 2018

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backend:X86bugzillagood first issuellvm:analysis

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Description
Bugzilla Link 39153
Version trunk
OS Windows NT
CC @adibiagio,@topperc,@LebedevRI,@rotateright
Fixed by commit(s) rG8ead5df0b119

Extended Description

Add ValueTracking and SelectionDAG ComputeKnownBits support for BEXTR intrinsics

Contributor guide

Research direction
Study existing ComputeKnownBits implementations for X86 intrinsics in ValueTracking and SelectionDAG, then extend them to handle BEXTR by examining its semantics (bit field extract) and adding corresponding compute logic.
Tech stack
c
Domain
backend
Issue type
Feature
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.
1-2 days
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
GitC++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30