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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/102285] New flag -ftrivial-auto-var-init=zero causes
 crash in pr82421.c
Date: Mon, 04 Oct 2021 06:27:29 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102285

--- Comment #19 from rguenther at suse dot de <rguenther at suse dot de> ---
On Fri, 1 Oct 2021, qing.zhao at oracle dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102285
>=20
> --- Comment #16 from Qing Zhao <qing.zhao at oracle dot com> ---
> > On Oct 1, 2021, at 1:51 AM, rguenth at gcc dot gnu.org <gcc-bugzilla@gc=
c.gnu.org> wrote:
> >=20
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102285
> >=20
> > --- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
> > Because the variable doesn't need to be addressable.
>=20
> One question:
>=20
> For the following statement in the routine =E2=80=9Cfold_builtin_alloca_w=
ith_align=E2=80=9D in
> tree-ssa-ccp.c:
>=20
>=20
>   /* Fold alloca to the address of the array.  */
>   return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var));
>=20
> Clearly, we build a add_expr for =E2=80=9Cvar=E2=80=9D, but why not =E2=
=80=9Cmark_addressable=E2=80=9D for
> =E2=80=9Cvar=E2=80=9D since its address is taken?

The address will be propagated and the operand scanner will mark it
addressable when it ends in a context where it needs to be.=