# Understanding ByValOptimization on MemCpyOpt

## What is ByVal Optimization on MemCpyOpt?

a part of MemCpyOptimizer on LLVM-middleend path

https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp#L1538-L1539

Let's show the overview of this pass(on 2023/05/28)
TODO: are there any optimization using byval attributes except MemCpyOptimizer?

### ByVal attributes

## The conditions to remove `memcpy` of byval Arguments

### Memory clobber

### alignment