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Re: [PATCH][RFC] Allow forwprop to propagate into mutliple uses
- From: Jeffrey A Law <law at redhat dot com>
- To: Richard Guenther <rguenther at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 26 Jul 2005 11:47:19 -0600
- Subject: Re: [PATCH][RFC] Allow forwprop to propagate into mutliple uses
- References: <Pine.LNX.firstname.lastname@example.org>
- Reply-to: law at redhat dot com
On Tue, 2005-07-26 at 10:47 +0200, Richard Guenther wrote:
> This patch serves as a temporary fix for the lack of a tree-combiner
> in 4.1. It allows forwprop to propagate ADDR_EXPRs into multiple
> uses, which helps C++ testcases quite a bit. I added an (unused) flag
> so that we maybe can restrict this extra propagation to the first
> forwprop pass only. I will do some benchmarking, if you think that
> such patch may be accepted for 4.1 (my benchmarking sofar was on
> tramp3d only and with array aliasing enabled - with the forwprop
> change we gain ~30% in performance, while without, it does not improve).
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
> 2005-07-26 Richard Guenther <email@example.com>
> * tree-ssa-forwprop.c (forward_propagate_addr_expr): Add
> argument to tell whether we want to propagate into multiple
> uses. Handle this case.
> (tree_ssa_forward_propagate_single_use_vars): Adjust caller,
> always propagate into multiple uses for now.
I would suggest waiting -- I don't think this is really appropriate
for stage3. In fact, it's probably time to create a mega bug for