Int vs Word performance?

Simon Peyton-Jones simonpj at
Fri Feb 27 11:36:39 EST 2009

| Until I stumbled over CORE annotations, I found it near impossible even
| to find the pieces of interest for non-trivial programs, things like
| -dsuppress-uniques help a little with diffs, some things look big but
| are noops, etc. - that kind of helpful pragmatic knowledge (why does
| it look as if source variable names aren't always preserved; why does
| it use random uniques instead of de Bruijn-style disambiguation, which
| wouldn't interfere with diffs and would have static semantic content;
| why do the outputs look different for core2core vs dump-simpl, ..).

Many of these things might be fixable if someone thought about the specification carefully.  The current core pretty-printer was initially designed only for GHC internals hackers, rather than Joe User.

A first step might be for a posse of Joe Users to specify what they want, as precisely as possible.  Then this same posse might even write a Core pretty-printer to achieve it. I am happy to advise.  Then we could substitute new for old.

| A quick grep shows almost no specialization at all for Word, or for
| IntXX/WordXX (see below). Still, none of that seems to explain the
| example repeated at the top of this message.

We'd be delighted to apply suitable library patches.


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