Re: [Haskell-cafe] Haskell version of ray tracer code is much slower than the original ML

On Thu, Jun 21, 2007 at 03:29:17PM -0400, Mark T.B. Carroll wrote:

Philip Armstrong writes: (snip)

...

Why on earth would you use -fexcess-precision if you're using Floats? The excess precision only apples to Doubles held in registers on x86 IIRC. (If you spill a Double from a register to memory, then you lose the extra precision bits in the process).

Some googling suggests that point 2 on http://www.haskell.org/hawiki/FasterFloatingPointWithGhc might have been what I was thinking of.

That's the old wiki. The new one gives the opposite advice! (As does the ghc manual): http://www.haskell.org/ghc/docs/latest/html/users_guide/faster.html http://www.haskell.org/haskellwiki/Performance/Floating_Point Phil -- http://www.kantaka.co.uk/ .oOo. public key: http://www.kantaka.co.uk/gpg.txt