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Re: [RTL] canonical form of AND-immediate within COMPARE?
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Kyrill Tkachov <kyrylo dot tkachov at arm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Segher Boessenkool <segher at kernel dot crashing dot org>
- Date: Thu, 03 Dec 2015 16:15:58 +0100
- Subject: Re: [RTL] canonical form of AND-immediate within COMPARE?
- Authentication-results: sourceware.org; auth=none
- References: <5660567D dot 2070403 at arm dot com>
> Some ISAs have instructions to perform a bitwise AND operation with an
> immediate and compare the result with zero.
Many of them I'd say.
> Is there a good way to fix this? It would seem rather weird to have extra MD
> patterns to match the zero_extract forms explicitly. Maybe teaching the
> aarch64 implementation of SELECT_CC_MODE to handle ZERO_EXTRACTS the same
> as AND-immediates? Or is there something that can be done in combine
> itself?
ARM, i386, MIPS, PA, SPARC, etc have ZERO_EXTRACT-based patterns though.
--
Eric Botcazou