On Tue, Jul 13, 2010 at 4:50 PM, Paolo Bonzini <bonz...@gnu.org> wrote: > On 07/08/2010 10:58 PM, Maxiwell Garcia wrote: >> >> Hi, >> >> I am writing a paper about instruction-set architecture simulators. In >> first time, I used gcc-4.4.0 and the compilation time reached 33 >> minutes (with -O3) for my simulator and the performance reached 270 >> MIPS (Million instruction per second). When I used the gcc-4.4.4, in >> the same code, the compilation time reached 39 seconds and the >> performance reached 600 MIPS. My code have many "switchs" with 512 >> "cases" and the library<systemc.h> is in use. >> How to explain this behavior in the compilation and performance in my >> paper? > > Try -ftime-report, it should explain the compilation time change. Such a > dramatic performance change is usually due to better register allocation, > but this is just a guess.
I would guess it was the various backports of tree PRE fixes actually. Richard. > Paolo >
