[Bug tree-optimization/102511] [12 Regression] GCC produces incorrect code for -O3: first element of the array is skipped after r12-3903

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102511
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Aldy Hernandez <al...@gcc.gnu.org>:

https://gcc.gnu.org/g:fb8b72ebb5b0bf40f7dfef9154c42320ce46f2a7

commit r12-3916-gfb8b72ebb5b0bf40f7dfef9154c42320ce46f2a7
Author: Aldy Hernandez <al...@redhat.com>
Date:   Tue Sep 28 09:38:50 2021 +0200

    Return VARYING in range_on_path_entry if nothing found.

    The problem here is that the solver's code solving unknown SSAs on entry
    to a path was returning UNDEFINED if there were no incoming edges to the
    start of the path that were not the function entry block.  This caused a
    cascade of pain down stream.

    Tested on x86-64 Linux.

            PR tree-optimization/102511

    gcc/ChangeLog:

            * gimple-range-path.cc (path_range_query::range_on_path_entry):
            Return VARYING when nothing found.

    gcc/testsuite/ChangeLog:

            * gcc.dg/pr102511.c: New test.
            * gcc.dg/tree-ssa/ssa-dom-thread-14.c: Adjust.