llvm/llvm-project

[DAG] computeKnownFPClass - add ISD::MAXNUM/MINNUM handling + test coverage

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#189,694 opened on Mar 31, 2026

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good first issuellvm:SelectionDAG

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Description

ISD::FMAXIMUM/ISD::FMINIMUM + ISD::FMAXIMUMNUM/ISD::FMINIMUMNUM handling can be added as well

This will need to be based off the implementation in computeKnownFPClass in ValueTracking.cpp - DenormalMode access might take some additional patches / test coverage

This should be tested with IR tests and not unit tests

Contributor guide

Research direction
Study the existing computeKnownFPClass implementation in ValueTracking.cpp, understand how ISD::FMAXIMUM and similar are handled, then add analogous handling for ISD::MAXNUM/MINNUM, ISD::FMAXIMUMNUM/FMINIMUMNUM. Write IR tests to cover the new cases.
Tech stack
None
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.
3-5 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.
Mostly clear
Prerequisites
C++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30