[Bug c++/80593] [7 Regression] GCC 7, aligned_storage and “dereferencing type-punned pointer will break strict-aliasing rules”

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80593

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Jun  7 13:07:06 2017
New Revision: 248970

URL: https://gcc.gnu.org/viewcvs?rev=248970&root=gcc&view=rev
Log:
2017-06-07  Richard Biener  <rguent...@suse.de>

        Backport from mainline
        2017-05-02  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/80549
        * tree-cfgcleanup.c (mfb_keep_latches): New helper.
        (cleanup_tree_cfg_noloop): Create forwarders to known loop
        headers if they do not have a preheader.

        * gcc.dg/torture/pr80549.c: New testcase.

        2017-05-19  Richard Biener  <rguent...@suse.de>

        PR c++/80593
        * c-warn.c (strict_aliasing_warning): Do not warn for accesses
        to alias-set zero memory.

        * g++.dg/warn/Wstrict-aliasing-bogus-char-2.C: New testcase.
        * g++.dg/warn/Wstrict-aliasing-6.C: Adjust expected outcome.

        2017-05-26  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/80842
        * tree-ssa-ccp.c (set_lattice_value): Always meet with the old
        value.

        * gcc.dg/torture/pr80842.c: New testcase.

        2017-05-31  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/80906
        * graphite-isl-ast-to-gimple.c (copy_loop_close_phi_nodes): Get
        and pass through iv_map.
        (copy_bb_and_scalar_dependences): Adjust.
        (translate_pending_phi_nodes): Likewise.
        (copy_loop_close_phi_args): Handle code-generating IVs instead
        of ICEing.

        * gcc.dg/graphite/pr80906.c: New testcase.

        2017-05-11  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/80705
        * tree-vect-data-refs.c (vect_analyze_data_refs): DECL_NONALIASED
        bases are not vectorizable.

        * gcc.dg/vect/bb-slp-pr80705.c: New testcase.

Added:
   
branches/gcc-7-branch/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-bogus-char-2.C
    branches/gcc-7-branch/gcc/testsuite/gcc.dg/graphite/pr80906.c
    branches/gcc-7-branch/gcc/testsuite/gcc.dg/torture/pr80549.c
    branches/gcc-7-branch/gcc/testsuite/gcc.dg/torture/pr80842.c
    branches/gcc-7-branch/gcc/testsuite/gcc.dg/vect/bb-slp-pr80705.c
Modified:
    branches/gcc-7-branch/gcc/ChangeLog
    branches/gcc-7-branch/gcc/c-family/ChangeLog
    branches/gcc-7-branch/gcc/c-family/c-warn.c
    branches/gcc-7-branch/gcc/graphite-isl-ast-to-gimple.c
    branches/gcc-7-branch/gcc/testsuite/ChangeLog
    branches/gcc-7-branch/gcc/testsuite/g++.dg/warn/Wstrict-aliasing-6.C
    branches/gcc-7-branch/gcc/tree-cfgcleanup.c
    branches/gcc-7-branch/gcc/tree-ssa-ccp.c
    branches/gcc-7-branch/gcc/tree-vect-data-refs.c