PLSE Blog

Hello, and welcome to the first edition of the official UW PLSE blog!

Hi! My name is Matt (he/him), one of the new teaching faculty at the Allen School this fall. I’ve been given a warm welcome by the community at UW, including at PLSE – where I’ve already met some wonderful people who do all things software engineering, programming languages, and running!

The phase-ordering problem is a long standing problem in program optimization: Consider program \((a\times 2)/2\). A program optimizer may readily optimize the subexpression \(a\times 2\) into \(a\ll 1\) and get \((a\ll 1)/2\), at which stage it cannot optimize the program further. Or it can also realize that the multiplication and division operators can be simply canceled out, yielding \(a\). This indicates that applying one optimization may disable another optimization, but naively exploring all optimization orders can lead to a combinatorial explosion.