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Date: Thu, 28 Oct 2021 14:34:32 +0200
From: Jan Hubicka <hubicka@kam.mff.cuni.cz>
To: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
Cc: gcc-bugs@gcc.gnu.org, mliska@suse.cz
Subject: Re: [Bug ipa/102982] [12 Regression] Dead Code Elimination
 Regression at -O3 (trunk vs 11.2.0)
Message-ID: <20211028123432.GA52780@kam.mff.cuni.cz>
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> 
> fixup_cfg already removes write-only stores so that seems fit for that
> purpose.
> 
> Btw,
> 
> static int x = 1;
> 
> int main()
> {
>   x = 1;
> }
> 
> should ideally be handled as well as maybe the more common(?)
> 
> static int x[128];
> 
> int main()
> {
>   memset (x, 0, 128*4);
> }
> 
> so we'd like to store a (constant) RHS for the stores in the summaries?
> (I suppose we cannot selectively stream in a single stmt ;))

Yep, what we want is to have way to attach summaries to particular
IPA_REF_load/store/addr just like we annotate call sites...
It would be nice to extend symbol-summary.h for that.  Martin, would you
be interested to look into it?

Honza