[Bug middle-end/80341] [5/6 Regression] gcc miscompiles division of signed char

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80341

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Jun 22 07:30:03 2017
New Revision: 249499

URL: https://gcc.gnu.org/viewcvs?rev=249499&root=gcc&view=rev
Log:
2017-06-22  Richard Biener  <rguenther@suse.de>

        Backport from mainline
        2017-04-20  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/80453
        * tree-ssa-sccvn.h (struct vn_phi_s): Add cclhs and ccrhs members.
        * tree-ssa-sccvn.c (cond_stmts_equal_p): Use recorded lhs and rhs
        from the conditions.
        (vn_phi_eq): Pass them down.
        (vn_phi_lookup): Record them.
        (vn_phi_insert): Likewise.

        2017-04-07  Richard Biener  <rguenther@suse.de>

        PR middle-end/80341
        * tree.c (get_unwidened): Also handle ! for_type case for
        INTEGER_CSTs.
        * convert.c (do_narrow): Split out from ...
        (convert_to_integer_1): ... here.  Do not pass final truncation
        type to get_unwidened for TRUNC_DIV_EXPR.

        * gcc.dg/torture/pr80341.c: New testcase.

        2017-04-04  Richard Biener  <rguenther@suse.de>

        PR middle-end/80281
        * match.pd (A + (-B) -> A - B): Make sure to preserve unsigned
        arithmetic done for the negate or the plus.  Simplify.
        (A - (-B) -> A + B): Likewise.
        * fold-const.c (split_tree): Make sure to not negate pointers.

        * gcc.dg/torture/pr80281.c: New testcase.

Modified:
    branches/gcc-6-branch/gcc/ChangeLog
    branches/gcc-6-branch/gcc/convert.c
    branches/gcc-6-branch/gcc/fold-const.c
    branches/gcc-6-branch/gcc/match.pd
    branches/gcc-6-branch/gcc/testsuite/ChangeLog
    branches/gcc-6-branch/gcc/tree-ssa-sccvn.c
    branches/gcc-6-branch/gcc/tree-ssa-sccvn.h
    branches/gcc-6-branch/gcc/tree.c