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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94951] [8/9 Regression] dereferencing type-punned pointer
 will break strict-aliasing rules when using super class for a template type
Date: Wed, 16 Sep 2020 19:22:01 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94951

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:eca1dbea010ba4c18ccec90bacbad5d8ec72c09f

commit r9-8897-geca1dbea010ba4c18ccec90bacbad5d8ec72c09f
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed May 6 23:38:13 2020 +0200

    c++: Avoid strict_aliasing_warning on dependent types or expressions
[PR94951]

    The following testcase gets a bogus warning during build_base_path,
    when cp_build_indirect_ref* calls strict_aliasing_warning with a depend=
ent
    expression.  IMHO calling get_alias_set etc. on dependent types feels w=
rong
    to me, we should just defer the warnings in those cases until instantia=
tion
    and only handle the cases where neither type nor expr are dependent.

    2020-05-06  Jakub Jelinek  <jakub@redhat.com>

            PR c++/94951
            * typeck.c (cp_strict_aliasing_warning): New function.
            (cp_build_indirect_ref_1, build_reinterpret_cast_1): Use
            it instead of strict_aliasing_warning.

            * g++.dg/warn/Wstrict-aliasing-bogus-tmpl.C: New test.

    (cherry picked from commit d82414ebcf7716ea24688510594a2c464a105908)=