Date: Tue, 2 Mar 2010 23:57:20 -0500 From: "illoai@gmail.com" <illoai@gmail.com> To: Aaron Lewis <aaron.lewis1989@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: Compiler Flags problem with core2 CPU Message-ID: <d7195cff1003022057t594281eblf2ba394662e132dd@mail.gmail.com> In-Reply-To: <4B8A63D5.90104@gmail.com> References: <4B8A63D5.90104@gmail.com>
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On 28 February 2010 07:38, Aaron Lewis <aaron.lewis1989@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. -- --help
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