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Re: [PATCH] Use alias-oracle for memmove -> memcpy folding
- From: Richard Guenther <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 2 Sep 2009 14:00:00 +0200 (CEST)
- Subject: Re: [PATCH] Use alias-oracle for memmove -> memcpy folding
- References: <alpine.LNX.2.00.0908311434460.28140@zhemvz.fhfr.qr>
On Mon, 31 Aug 2009, Richard Guenther wrote:
>
> This changes the folding code that transforms memmove to memcpy to
> use the alias oracle to query whether the memory arguments may overlap.
> The patch also relaxes what we accept for pointers in INDIRECT_REFs
> in the oracle to allow easy use of it even from the early folders
> where we are not in gimple form.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
I failed to test ada and the patch caused some regressions there
(basically using the oracle when we're not yet in gimple is fragile
due to the FEs not setting TREE_ADDRESSABLE properly and also due
to extra weird trees popping up). The proper fix is to move this
folding to fold_stmt only - I don't have time for this right now
so I have reverted the patch.
Richard.