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Re: [PATCH] Fix PR rtl-optimization/27661 (reload problem)
- From: uweigand at de dot ibm dot com
- To: bernds_cb1 at t-online dot de (Bernd Schmidt)
- Cc: uweigand at de dot ibm dot com (Ulrich Weigand), gcc-patches at gcc dot gnu dot org
- Date: Thu, 25 May 2006 20:30:54 +0200 (CEST)
- Subject: Re: [PATCH] Fix PR rtl-optimization/27661 (reload problem)
Bernd Schmidt wrote:
> From the sounds of it, you don't want the insn to end up with a
> constant in the address anyway, so can't you just disallow these kinds
> of addresses in GO_IF_LEGITIMATE_ADDRESS?
No, the address is perfectly legitimate, and other instructions
will accept it, just this particular insn (alternative) doesn't.
We have different types of instructions accepting different variants
of valid addresses, some accept an index register and some don't,
and some accept only a 12-bit unsigned displacement while others
accept a 20-bit signed displacement. I must accept *all* these
variants as legitimate addresses -- the insn constraints then work
out the fine details ...
Bye,
Ulrich
--
Dr. Ulrich Weigand
Linux on zSeries Development
Ulrich.Weigand@de.ibm.com