Re: gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ?

From: Jakub Jelinek
Date: Mon Nov 15 2010 - 05:04:47 EST


On Mon, Nov 15, 2010 at 09:56:05AM +0100, Jakub Jelinek wrote:
> On Sun, Nov 14, 2010 at 07:21:50PM -0800, Linus Torvalds wrote:
> > So when Richard Gunther says "a memory clobber doesn't cover automatic
> > storage", to me that very clearly spells "gcc is buggy as hell".
> > Because automatic storage with its address taken _very_ much gets
> > clobbered by things like memset etc. If the compiler doesn't
> > understand that, the compiler is just broken.
>
> I'll leave the discussion about meaning of "memory" clobber aside to
> Richard,

And for this the starting point should be what has been requested,
i.e. preprocessed source + gcc options + gcc version and some hints what
actually misbehaves (with the , "+m" (*regs) change reverted)
in gcc bugzilla. Only with that we can actually look at what has been
happening, see whether it is the tree optimizations or RTL and which one
makes a difference.
If I've missed a PR about this I apologize.

Jakub
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