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From: "hubicka at kam dot mff.cuni.cz" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug ipa/102982] [12 Regression] Dead Code Elimination Regression at
 -O3 (trunk vs 11.2.0)
Date: Thu, 28 Oct 2021 12:34:35 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102982

--- Comment #6 from hubicka at kam dot mff.cuni.cz ---
>=20
> fixup_cfg already removes write-only stores so that seems fit for that
> purpose.
>=20
> Btw,
>=20
> static int x =3D 1;
>=20
> int main()
> {
>   x =3D 1;
> }
>=20
> should ideally be handled as well as maybe the more common(?)
>=20
> static int x[128];
>=20
> int main()
> {
>   memset (x, 0, 128*4);
> }
>=20
> 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=