Re: [gentoo-user] gcc upgrade - rebuild everything?

[Grant <emailgrant@gmail.com>]

>> I just upgraded from gcc-4.4.3-r2 to gcc-4.4.4-r2 and I'm wondering if
>> I really need to rebuild everything as it says in the guide:
>>
>> http://www.gentoo.org/doc/en/gcc-upgrading.xml
>
> No, you do not need to do this. The document is over-reaching (see below)
>
> I ran a mixture of 4.4.3 and 4.4.4 for ages, completely trouble-free.
>
>> If not, when is it necessary?
>
> When you have an ABI change in the code generated by the compiler. In other
> words, when code generated by this version is incompatible with code generated
> by that version, and you have both on the same system. This has not happened
> for a long time in gcc-land.
>
> Now, about that official doc. Your question comes up with unbelievable
> regularity and every time the poster references that doc. But it is not
> necessary to do what the doc says, and a long time ago I think I figured it
> out.
>
> The author's intention is less to give you the absolute complete total 100%
> truth that will always work out just fine, and more to reduce the amount of
> clutter in his inbox or on b.g.o.
>
> The rules about how to detect when a rebuild of world is needed are complex
> and most readers simply will not understand them - they don't understand
> compiler internals (how many people DO?). But if you tell people to just
> rebuild world every time, and weird funny lurking problems are likely to just
> get fixed as a side effect, no real harm is done. Does it hurt the author? No.
> Does it reduce the amount of bugs he has to deal with on the rare occasion it
> is needed? Yes.
>
> What does the user lose? Nothing much, more cpu cycles get used, more bits
> flip on a disk, your video card gets a work out scrolling all that text. Will
> you waste time? Yes. Will you break stuff? No.
>
> So rebuild world if it makes you feel better. But you don't need to this time.
> The authors of gcc will certainly notify the entire world and it's dogs when
> you do need to.

Thank you everyone.  I won't rebuild.

- Grant