The thing is that compilers usually quickly go to SSA form and it is not the best IR to optimize loops in. Then you fight it to extract a high-level IR and this

The thing is that compilers usually quickly go to SSA form and it is not the best IR to optimize loops in. Then you fight it to extract a high-level IR and this little process makes it very easy to lose high-level information. We don't do this so we begin from a friendlier starting point.