Heads Up: gcc-4.6 -march=corei7 -mtune=corei7 doesn't work

3vi1 · Post by **3vi1** » Sat Jul 02, 2011 10:36 am

Noticed something I thought I would share so that others don't scratch their head wondering about it if they try the same.

I updated my system to Oneiric, and decided to recompile Wine. I tried making use of the corei7 optimizations in gcc 4.6 and found that, while a lot of stuff worked (ex. Steam), other things (like DirectX games) did not.

So, as always... don't expect things to work when turning on optimizations.

jorl17 · Post by **jorl17** » Sat Jul 02, 2011 11:12 am

Can anyone else confirm? I'm currently installing a new Gentoo on a corei7 and have been using those flags. One of the first things I am going to do right after I get it fully setup is grab Wine and compile it from the sources and I am/was tempted to use those flags.

Thanks,
Jorl17

love2hate · Post by **love2hate** » Sat Jul 02, 2011 11:49 am

You use LTO flag ?

jorl17 · Post by **jorl17** » Sat Jul 02, 2011 5:29 pm

Unless somehow it got selected, I don't. I use -march=native

DL · Post by DL » Sat Jul 02, 2011 9:11 pm

Are you using a Sandy Bridge system 3vi1? The AVX instructions that get enabled when using -march=native with SB result in failed compilation for some applications. Try these flags:

CFLAGS="-march=corei7 -mtune=corei7 -O2 -pipe"

DL · Post by DL » Sat Jul 02, 2011 9:14 pm

Sorry, got confused with jor17 and the original post (I see you're already using the same flags that I posted).

Wine does seem to be sensitive to compiler optimisation. You could try just applying these optimisations to wined3d if you're looking for more D3D performance. Profile guided optimisation works well there too.