[Bug c++/106131] [10/11/12/13 Regression] -fstrict-aliasing breaks normal program that does not use any pointer or reference

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106131

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with

commit 8403c2cf5f66758fc78a01a675b0d218fded0202
Author: Richard Biener <rguent...@suse.de>
Date:   Mon Nov 24 14:07:18 2014 +0000

    re PR target/63679 ([AArch64] Failure to constant fold.)

    2014-11-24  Richard Biener  <rguent...@suse.de>

            PR tree-optimization/63679
            * tree-ssa-sccvn.c: Include ipa-ref.h, plugin-api.h and cgraph.h.
            (copy_reference_ops_from_ref): Fix non-constant ADDR_EXPR case
            to properly leave off at -1.
            (fully_constant_vn_reference_p): Generalize folding from
            constant initializers.
            (vn_reference_lookup_3): When looking through aggregate copies
            handle offsetted reads and try simplifying the result to
            a constant.
            * gimple-fold.h (fold_ctor_reference): Export.
            * gimple-fold.c (fold_ctor_reference): Likewise.

            * gcc.dg/tree-ssa/ssa-fre-42.c: New testcase.
            * gcc.dg/tree-ssa/20030807-5.c: Avoid folding read from global to
zero.
            * gcc.target/i386/ssetype-1.c: Likewise.
            * gcc.target/i386/ssetype-3.c: Likewise.
            * gcc.target/i386/ssetype-5.c: Likewise.

    From-SVN: r218019