I have tried with gcc 3.4.4 and still see the same 20%slowdown. If you folks are able to crack this, do let me know. On my earlier attempts I had tried to disable all of the flags that feedback optimization turns on (except the ones that are turned on by default) and still got the 20% slowdown. Is there something that you would want me to try out wrt to enabling/disabling certain flags, i'd be happy to. The versions I have tried out so far are 2.95,3.4.3 and 3.4.4
-girish --- Jan Hubicka <[EMAIL PROTECTED]> wrote: > > > > There was some discussion a few weeks ago about > some apps running slower > > with FDO enabled. > > > > I've recently investigated a similar situation > using mainline. In my case, > > the fact that the loop_optimize pass is disabled > during FDO was the cause > > of the slowdown. It appears that was recently > disabled as part of Jan > > Hubicka's patch to eliminate RTL based profiling. > The commentary indicates > > that the old loop optimizer is incompatible with > tree profiling. > > > > While this doesn't explain all of the degradations > discussed (some were > > showing up on older versions of the compiler), it > may explain some. > > Do you have specific testcase? It would be > interesting to see if new > optimizer can catch up at least on kill-loop branch. > > Thanks for investigating! > Honza > > > > Pete >
