Combine exprIsTrivial and cpe_ExprIsTrivial
CorePrep.cpe_ExprIsTrivial. They are identical!
The latter has a comment saying
cpe_ExprIsTrivial :: CoreExpr -> Bool -- Version that doesn't consider an scc annotation to be trivial.
but the code does not treat ticks any differently.
So the question is: are they supposed to be different? And if not, can we just combine them?
Peter W, Simon M: this is your territory. I don't understand tick stuff well enough.