The acyclic e-graph: Cranelift's mid-end optimizer

…6828) ## Summary `GuardType` narrows only its result id, not the original input. A later guard on the same input therefore looks unfoldable to `fold_constants` even though the side-exit semanti...

In compilers, static single information form (SSI) is a common extension to static single assignment form (SSA). It was introduced by C. Scott Ananian in 1999 in his MS thesis (PDF) 1. …and optimized in 2002 (PDF), ↩