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Re: [PATCH] SPARC psABI fix, callee returns struct checking.
On Wed, Mar 08, 2006 at 03:06:46PM -0800, David S. Miller wrote:
> > Accept the patch and I'll subsequently add a flag to turn it all off if
> > you want really fast performance (e.g. remove caller and callee side
> > fiddling and just assume the pointer to the save area is always there
> > and the correct size). Please start thinking of a flag name.
> >
> > Ok?
>
> I really have a hard time accepting a load of an instruction that will
> use up an unnecessary data TLB entry (a scarce and precious resource)
> that is unneeded %99.9999999 of the time.
Okay, lets reverse the meaning of the compile time flag?
Machine Dependant Options
SPARC Options ... -mpsabi32
-mpsabi32
When the flag is present gcc is in strict adherence
to the 32-bit SPARC psABI. When the flag is not present
gcc takes certain psABI liberties, including the removal
of the unimp load in callee returns struct cases.
The flag would effect the code emitted in sparc.md (struct_prologue).
Ok?
Cheers,
Carlos.
--
Carlos O'Donell
CodeSourcery
carlos@codesourcery.com
(650) 331-3385 x716