Re: [PATCH] [20/45] x86_64: Use 8 byte stack alignment when possible

Dave Jones
2007-09-21T22:58:46Z

On Sat, Sep 22, 2007 at 12:34:31AM +0200, Andi Kleen wrote:
> On Friday 21 September 2007 23:13, Dave Jones wrote:
> > On Fri, Sep 21, 2007 at 10:45:02PM +0200, Andi Kleen wrote:
> > > Kernel doesn't use SSE2, so it doesn't need 16 byte alignment. Also
> > > the stack can be already unaligned so letting the compiler align
> > > is useless. This may make some stack frames smaller.
> > > Only works with very recent gcc 4.3
> >
> > My gcc 4.1.2 from Fedora 7 (with who knows what backported)
> > references this in its manpage. How was it broken before 4.3 ?
>
> Try it. It is rejected by the compiler in 64bit mode.

Ah yes, it fails if not between 4 & 12, but the call cc-option
catches that. Looks fine to me.

Dave

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