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Re: abs insn with QI and HI mode
On Tue, Jul 10, 2007 at 10:35:01AM +0100, Ying Yi wrote:
> Hi Jim,
> >To get your special char/short abs instructions, we need one of two things
> >1) Optimization support to recognize a sign-extend followed by an abs,
> >where the target has an abs instruction that operates on the
> >pre-extended value. We can then optimize away the sign extend
> >instruction. This optimization support apparently does not exist at
> >the moment, perhaps because no one has needed it before.
> Thanks very much for your email. Will gcc add the optimization support
> in the future (method 1)?
Please don't top post. Thanks.
Shameless plug: Get trunk revision 126251 or later and compile with
-fdump-rtl-combine-details, then look at the dump file. There is a good
chance that combine is already looking for such an instruction.
Rask Ingemann Lambertsen