Hello,

I'm sure this has been asked before but, clearly, my archive search 
skills are sub-par. I'm hoping it would be a quick "yes/no" kind of answer.

Long story short, I decided to try out the Gentoo setup with binary 
package host. I've been making my way through the relevant news item [1] 
and guides [2,3].

I already have "/etc/portage/binrepos.conf" and "/etc/portage/gnupg" set 
up correctly - no issues there. In make.conf I also added:

     FEATURES="getbinpkg binpkg-request-signature"

My only question that remains is whether I should change the existing 
value for CFLAGS (I presume so). Currently, I have:

     COMMON_FLAGS="-march=znver4 -O2 -pipe"

(yes CFLAGS etc are set to use $COMMON_FLAGS).

Since I'm planning to use binary packages from x86-64-v3, I presume this 
should be changed to:

     COMMON_FLAGS="-march=x86-64-v3 -O2 -pipe"

or, perhaps:

     COMMON_FLAGS="-march=x86-64-v3 -mtune=znver4 -O2 -pipe" ?

I also have a hefty $CPU_FLA
GS_X86 (also added to $USE) from 
"cpuid2cpuflags" but am not worried about this as packages that don't 
fit will simply be built from source as usual.

Anyway, in both cases running my usual:

     emerge -aqvND --update --keep-going --with-bdeps=y @world

doesn't yield any changes to the system. I presume because, as of now, 
everything is up to date.

In contrast, adding "--rebuilt-binaries" shows a lot of binary packages 
being pulled in and "--emptytree", as expected, shows a full rebuild 
with a lot of binary packages being pulled in.

So, to the actual questions:

1) What would be the preferred CFLAGS configuration or, since 
"-march=znver4" is a newer subset of x86-64-v3, can I simply keep the 
existing one?

2) To reinstall the current source based packages with their binary 
equivalent, "--rebuilt-binaries" sufficient or should I just go for 
"--emptytree @world"?

Thanks,
Victor

[1] https://www.gentoo.org/news/2023/12/29/Gentoo-binary.html
[2] h
ttps://wiki.gentoo.org/wiki/Gentoo_Binary_Host_Quickstart
[3] https://wiki.gentoo.org/wiki/Binary_package_guide