[Bug tree-optimization/94166] [10 Regression] random -fcompare-debug failures since r10-1913

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94166

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:5ba25b2ef179aec8ba4c47612fbc5c388f41cb36

commit r10-7185-g5ba25b2ef179aec8ba4c47612fbc5c388f41cb36
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Mar 16 09:02:21 2020 +0100

    tree-inline: Fix a -fcompare-debug issue in the inliner [PR94167]

    The following testcase fails with -fcompare-debug.  The problem is that
    bar is marked as address_taken only with -g and not without.
    I've tracked it down to insert_init_stmt calling gimple_regimplify_operands
    even on DEBUG_STMTs.  That function will just insert normal stmts before
    the DEBUG_STMT if the DEBUG_STMT operand isn't gimple val or invariant.
    While DCE will turn those statements into debug temporaries, it can cause
    differences in SSA_NAMEs and more importantly, the ipa references are
    generated from those before the DCE happens.
    On the testcase, the DEBUG_STMT value is (int)bar.

    We could generate DEBUG_STMTs with debug temporaries instead, but I fail to
    see the reason to do that, DEBUG_STMTs allow other expressions and all we
    want to ensure is that the expressions aren't too large (arbitrarily
    complex), but during inlining/function versioning I don't see why something
    would queue a DEBUG_STMT with arbitrarily complex expressions in there.

    2020-03-16  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/94166
            * tree-ssa-reassoc.c (sort_by_mach_mode): Use SSA_NAME_VERSION
            as secondary comparison key.

            * gcc.dg/pr94166.c: New test.