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Re: ABI change for ports with byte-aligned functions.


On May  4, 2001, Geoff Keating <geoffk@geoffk.org> wrote:

>> Is there any reason you didn't use that patch?

> I was unaware of it.  Feel free to correct my patch, I just wanted
> something that would work.

It seems to me that it would be easier to revert your patch and
install mine.  But I'd rather hear from the ABI committee first.
Nathan, IIRC, you had brought this up to the committee.  Was there any
decision on this problem yet?

> No, changing FUNCTION_BOUNDARY for performance reasons is wrong.  The
> compiler will optimise bit operations on function pointers assuming
> that FUNCTION_BOUNDARY is correct, so any change to FUNCTION_BOUNDARY
> is an ABI change even in C.

Err...  grep FUNCTION_BOUNDARY *.c doesn't reveal anything that would
do this kind of optimization.  Besides, I don't see how this
optimization would incur in an ABI change.  Could you please clarify?

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me


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