Compiler Flags problem with core2 CPU
illoai at gmail.com
illoai at gmail.com
Wed Mar 3 04:57:25 UTC 2010
On 28 February 2010 07:38, Aaron Lewis <aaron.lewis1989 at gmail.com> wrote:
> Hi,
> I gonna recompile kernel for my core2 CPU , so i'd like to pass some flags
> to gcc.
> Kinds of "-march=core2" , i tried to modify /etc/make.conf
> e.g CFLAGS += -march=core2 -O20 -ffast-math -mfpmath=sse
> But it fails .. bad arch switch , core2 cpu is not supported ?
Just so you know -O20 is the same as saying -O3.
I don't think everything in base is safe for -ffast-math,
but setting it in make.conf will surely test that.
-O2 is already turned on almost everywhere by default,
so also, I believe, with -fomit-frame-pointer. The only
thing I've ever found to be remotely useful to change
was -Os on an old, space-restricted machine. But
last time I tried -Os on amd64 it broke. Badly.
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