Alan Cox on the Linux kernel, egcs, and gcc 2.8.x

[Joe Buck]

Since there's been some confusion on this issue, I thought it would
be useful to pass on this message from Alan Cox, the Linux
kernel/networking guru.  (Jeff, maybe there should be a FAQ entry
for this).

(Let me take this opportunity to plug the Linux Weekly News, BTW:
http://www.eklektix.com/lwn/ -- it's the best ongoing summary of
Linux activity I've seen).

Joe

> From: Alan Cox <alan@cymru.net>
> Subject: Re: gcc vs. egcs
> To: testers-list@redhat.com
> Date: Thu, 23 Apr 1998 10:55:07 +0100 (BST)

>> The following was reported in the Linux Weekly News for 4/23:
>> 
>>                   There has been an increase in the number of
>>                   people reporting kernel problems who are using
>>                   egcs or gcc-2.8. Folks should remember that the
>>                   kernel developers are currently quite unsympathetic
>>                   toward these problems; the Linux kernel is only
>>                   "supported" with gcc-2.7.2. Newer versions of the
>>                   compiler will take time... 
>
> That could be read slightly inaccurately
> 
> The situation is as follows
> 
> o       Linux 2.0.x builds correctly with gcc 2.7.2 (-1 and -3). 
> 
> o       Linux 2.1.x builds correctly with gcc 2.7.2, 2.8.1 and egcs (a few
>         errors keep popping up and people keep squashing them). 
> 
> I don't think there is anyone who doesn't intend 2.2.0 to work with 2.8.1
> and all the bugs people are finding now with gcc 2.8.1 are Linux not gcc
> bugs where the kernel forgot to stop gcc 2.8.1 optimising something we
> didnt want optimised, or from poor asm constraints on the linux code.
> 
> The problem is _nobody_ knows how many of those are still hiding in 2.0.x
> and introducing subtle races, so for safety we say build 2.0.x with 
> gcc-2.7.2-*.
> 
> So its an argument for what you build kernels with but its not an argument
> to which is the better compiler. Kernel code is just very touchy about
> such things.
> 
> Alan