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Re: [PATCH] Remove special-casing of PTR_IS_REF_ALL pointers from alias analysis
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Richard Guenther <rguenther at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org, Diego Novillo <dnovillo at google dot com>
- Date: Mon, 28 Apr 2008 22:30:51 +0200
- Subject: Re: [PATCH] Remove special-casing of PTR_IS_REF_ALL pointers from alias analysis
- References: <Pine.LNX.4.64.0804281808100.4130@zhemvz.fhfr.qr>
> Because they are just the same as pointed-to alias set zero or
> decls with DECL_NO_TBAA_P set or DECL_POINTER_ALIAS_SET zero.
I'm not sure: DECL_NO_TBAA_P and DECL_POINTER_ALIAS_SET are for decls,
PTR_IS_REF_ALL is for any pointer object.
> The handing of PTR_IS_REF_ALL pointers is also broken atm (and
> unnecessarily connects call clobber computation with flow insensitive
> aliasing). You can verify this by handling the other ref-all
> pointers (see above) the same -- all hell breaks lose.
Could you elaborate?
> So it's not worth to keep that code. Dead code is good code.
This code is not dead since there is TYPE_REF_CAN_ALIAS_ALL in the tree.
And I guess you need to remove the PTR_IS_REF_ALL macro as well then.
Btw, did you test Ada? Any regressions in the gnat.dg testsuite?
--
Eric Botcazou