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Re: RFC: Turn on -fomit-frame-pointer and -fasynchronous-unwind-tables for Linux/i386


On Sat, Jul 17, 2010 at 08:59:24PM +0100, Dave Korn wrote:
> On 16/07/2010 20:24, Andi Kleen wrote:
> > On Fri, Jul 16, 2010 at 05:21:16PM +0100, Dave Korn wrote:
> >> On 16/07/2010 09:13, Andi Kleen wrote:
> >>
> >>> (reference through %rbp is one byte smaller than through another GPR)
> >>> I believe MSVC does that and it's a useful optimization for x86.
> >>   I can't tell if you meant x86_64 or %ebp but those two statements don't
> >> quite go together as-is! :)
> > 
> > The optimization is valid for 32bit and 64bit.
> 
>   There's no such thing as %rbp in 32-bit x86 is all I meant.  Does the "one
> byte smaller" also apply to %ebp indirection on x86?

Yes. The two encodings are exactly the same.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.


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