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Re: combine canonicalization tweeks
- To: Richard Henderson <rth at cygnus dot com>
- Subject: Re: combine canonicalization tweeks
- From: Richard Earnshaw <rearnsha at arm dot com>
- Date: Mon, 29 May 2000 13:03:16 +0100
- Cc: gcc-patches at gcc dot gnu dot org
- Cc: rearnsha at arm dot com
- Organization: ARM Ltd.
- Reply-To: rearnsha at arm dot com
rth@cygnus.com said:
> * combine.c (combine_simplify_rtx): Don't create an
> if_then_else
> unless both args are general_operand. Don't canonicalize plus
> to ior unless it helps.
I fear this will cause worse code on the ARM, since in this case we can
support more complex expressions than general_operand; for example, we
have patterns to match
(if_then_else (comparison)
(ior (ashiftrt (reg, const)) (reg))
(reg))
and other very general patterns.
R.