Re: 2.2.0 and egcs 1.1 was Re: Sorry, wrong gcc-version

Linus Torvalds (torvalds@transmeta.com)
Sun, 25 Oct 1998 14:55:09 -0800 (PST)


On 25 Oct 1998, Andi Kleen wrote:
>
> Actually this is not entirely correct. Even 2.1.x kernels still have lots
> of incorrect inline assembler constraints which can cause the compiler
> to misoptimize the kernel.

I don't agree.

The assembler used to be correct, and the gcc people unilaterally decided
to change the rules. As such, I don't think the asm is any more
"incorrect" than the new gcc versions are incorrect.

The changes I have seen break older compilers.

So Andi, don't go saying that the kernel has problems, when it is equally
true to say that gcc has problems.

> In short, if you want to play safe stay with 2.7.2.3 for kernel compilation.

That, I think, everybody can agree on.

> Linus what is your position on egcs 1.1 and 2.2.0 ?

My problem is that I see too many egcs people that claim that the kernel
is buggy, even though at least half the reports I ever got were egcs bugs,
in my opinion. As such, I don't have very much faith in what the egcs
people tell me any more.

For example, everybody in the egcs camp just decided that clobbers and
inputs must not overlap. Nobody told me why, and why they can't just be
automatically converted to early-clobbers inside gcc.

Because clobbers and inputs used to be the only way to do certain things
in gcc, and now suddenly there's a witch-hunt going on against them.
That's sad.

Linus

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