Re: GCC proposal for "@" asm constraint

From: Andrea Arcangeli (andrea@suse.de)
Date: Tue Sep 19 2000 - 15:45:56 EST


On Tue, Sep 19, 2000 at 04:16:07PM -0400, John Wehle wrote:
> Umm ... "miscompilation"? As in the compiler produced the wrong code
> based on the input provided?

That's not a gcc bug (gcc is doing the right thing). It's the kernel that
should use the "memory" clobber in the spinlock implementation.

The sad code generated was in reality the _right_ code. I was blind not
noticing the missing $ (I missed it the first time in the first testcase I
tried and I kept missing it, I was probably also biased assuming the current
spinlocks was safe with the commonly used compilers, I was thinking to fix only
a theorical bug). I'm sorry for that (and thanks again to Richard and Jamie).

Andrea
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