llvm/llvm-project

[ConstantFolding] Move `LibCallSimplifier::optimizeFdim` into ConstantFolding

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#171,877 opened on Dec 11, 2025

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code-cleanupconstant-foldingfloating-pointgood first issue

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Description

In https://github.com/llvm/llvm-project/pull/109235 the constant folding logic was implemented in SimplifyLibCalls.cpp. But it should be put in ConstantFoldLibCall2 since both operands are known constants.

Contributor guide

Research direction
Familiarize yourself with the referenced PR #109235 to understand the existing implementation of `LibCallSimplifier::optimizeFdim`. Then locate the `ConstantFoldLibCall2` function and move the relevant logic from `SimplifyLibCalls.cpp` into `ConstantFolding`. Ensure the code compiles and tests pass.
Tech stack
cpp
Domain
backend
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.
Mostly clear
Prerequisites
C++Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60