On Tue, Nov 17, 2009 at 12:24 AM, Simon Peyton-Jones
To be honest I’m not terribly enthusiastic about trying to nail down exactly what’s happening in 6.10 and 6.12 because, although they are indeed the compilers people will be using, it’s otherwise wasted work because the HEAD is so different.
I don't blame you! That's completely reasonable.
Can you try with 6.12 and see if you can find a recipe that does well enough? If you get desperate (ie there’s a huge perf bump that you can’t eliminate) then I’ll certainly try to help.
Will do, thanks.
Meanwhile, I don’t know why 6.10 is faster than HEAD (by 25% too) and I’d like to understand that. Can you submit a Trac ticket saying how to reproduce? You might need to bundle up the library too, to make sure we can reproduce it precisely.
Certainly. The test program is tiny, but because of all the inlining in the library, the simplifier output is pretty fearsome.