Remi Turk wrote:
during the past semester I followed a seminar on the "Efficient implementation of functional languages" by Jeroen Fokker at the University Utrecht. During that course we worked on a feedback directed GHC optimisation, but that got me interested in another possible GHC backend micro-optimisation:
The short story is this:
An 8 line patch to GHC, tested with ghc 6.8.2 on nofib, ignoring all results with a < 0.5s runtime, yields an average runtime and compile time improvement of about 0.6%. The worst nofib slowdown is 5%, and the best speedup 8% Whether this is acceptable/enough for inclusion, is of course not up to me.
Hi Remi - thanks very much for the patch. It certainly looks worthwhile. I have some pending changes myself to mk_switch - it turns out that we're doing quite a bad job of compiling 3-way comparisons too (look at the code for fib sometime), so I'll try to incorporate your change into my refactorings. Cheers, Simon