ghc -fasm declared not too shabby

Simon Marlow simonmarhaskell at
Thu Mar 1 05:45:49 EST 2007

Donald Bruce Stewart wrote:
> Got some initial nobench numbers for ghc head -fvia-C versus -fasm, on
> amd64:
> Overall all of nobench, ghc -fasm averages 3% slower. Not too shabby!
> There's some wider variation on the microbenchmarks in the imaginary
> class:
>     one case 20% faster, another 30% slower, average 2% slower.

nsieve is interesting... I'm looking into it now.  Also the HEAD seems slower on 
that program.

> On real programs though, 3% slower on average.
> The big benefit of course, no perl, no gcc and faster compilation times.

I'd thought that -fasm was a slight improvement over -fvia-C on x86_64, so this 
is a surprise to me.  I know it's slower on x86, mainly due to the poor code 
generationg for floating point on x86.

You might consider discounting the programs that run for less than 0.1 seconds 
from the average, that's what nofib-analyse does.

BTW, what happened to imaginary/rfib?  I find that a useful floating point 


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