question regarding asm()

[Bernd Schmidt]

> I hoped to start looking at this.  I am concerned about breaking the
> Linux kernel due to changing semantics.  Have you considered changing
> it so it still has the same semantics regarding input/output reloads?

The kernel has been broken before by GCC changes. You can't compile Linux 1.2
with GCC 2.7.2.
The problem is, what exactly _are_ the current semantics for asm statements
on the x86? As far as I can tell, the clobbers are more or less ignored,
which is clearly wrong. I think it would be best to make the constraint
checking for asm statements more strict, even if that means that kernel
patches will become necessary.
BTW, could we increase MAX_RECOG_OPERANDS right now? This would make writing
correct asm statements a lot easier. I'll provide a patch if necessary.

Bernd