On Thu, May 5, 2011 at 2:16 PM, Quant <carkaci@xxxxxxxxx> wrote: > > I have recently upgrade my Ubuntu from 10.10 to 11.04. GCC version is also > upgraded from 4.4 to 4.5 automatically. However, some of my heavy math. C > codes run slower when compiled with GCC 4.5. > I have tried various optimization flags including "-fexcess-precision=fast". > But nothing changes, it runs slower comparing to the executable compiled > with GCC 4.4. > > By the way, I complied them with GCC 4.4 with "-03 -ffast-math". My machine > is IMAC I7. Ubuntu is 64bit. What kind of math... is there a small representative kernel of operations you could show? Is it in loops or large flat computations?
