Re: another compiler better than gcj ?

[Bryce McKinlay <bryce at waitaki dot otago dot ac dot nz>]

Tom Tromey wrote:

>Bryce> I had a play with this today. I was impressed. It didn't manage
>Bryce> to correctly run all the benchmarks I tried, but for those that
>Bryce> did work it generated some very slick code, blowing away both
>Bryce> GCJ and the IBM JDK at nearly everything I tried (mostly
>Bryce> numerical tests)
>
>It would be cool to see what it does differently.
>

Yeah. The Sieve.java case is most interesting because its just a loop 
with no allocation, no type checks, etc, so in theory the Java code 
should be just as fast as a C equivilant if you use --no-bounds-checks. 
Taking a quick look at the generated .s files it looked to me as if the 
Manta compiler was simply managing to compile the loop into fewer and 
more efficient instructions than GCJ could. Its also very interesting 
that GCJ 3.1 is nearly twice as fast as 3.0.2. Scimark is also hugely 
sped up between 3.0.2 and 3.1 - we used to be slower than the IBM VM and 
now we're twice as fast (but still not as fast as Manta). Whats changed?

regards

Bryce.