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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/101419] [9/10/11/12 Regression] collapsing
 memset() calls can break __builtin_object_size()
Date: Mon, 12 Jul 2021 11:56:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101419

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #12)
> (In reply to Jakub Jelinek from comment #10)
> > Created attachment 51139 [details]
> > gcc12-pr101419.patch
> >=20
> > Full untested patch.
>=20
> I guess that's certainly what was intended (and after the patch more
> explicit).  Whether it's good to not CSE any addresses in unrolled loop
> bodies is another question (but see my proposed pass order change which
> would fix this).

Note it might "break" GIMPLE FE testcases with startwith after the
objsz pass - break in the sense that later FRE will behave differently.

Note usually we still run all property providers but the way you set
the property outside of pass->properties_provided breaks this.  Thus
maybe split objsz into two separate passes rather than using the
flag so you can use properties_provided.=