[Bug tree-optimization/101590] (len & - N) <= len is not optimized to 1

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101590

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:a5e69e94591ae282857d59e868ff6cea7306c802

commit r14-4965-ga5e69e94591ae282857d59e868ff6cea7306c802
Author: Andrew Pinski <apinski@marvell.com>
Date:   Tue Sep 12 18:24:22 2023 -0700

    MATCH: Simplify `(X &| B) CMP X` if possible [PR 101590]

    I noticed we were missing these simplifications so let's add them.

    This adds the following simplifications:
    U & N <= U  -> true
    U & N >  U  -> false
    When U is known to be as non-negative.

    When N is also known to be non-negative, this is also true:
    U | N <  U  -> false
    U | N >= U  -> true

    When N is a negative integer, the result flips and we get:
    U | N <  U  -> true
    U | N >= U  -> false

    We could extend this later on to be the case where we know N
    is nonconstant but is known to be negative.

    Bootstrapped and tested on x86_64-linux-gnu with no regressions.

            PR tree-optimization/101590
            PR tree-optimization/94884

    gcc/ChangeLog:

            * match.pd (`(X BIT_OP Y) CMP X`): New pattern.

    gcc/testsuite/ChangeLog:

            * gcc.dg/tree-ssa/bitcmp-1.c: New test.
            * gcc.dg/tree-ssa/bitcmp-2.c: New test.
            * gcc.dg/tree-ssa/bitcmp-3.c: New test.
            * gcc.dg/tree-ssa/bitcmp-4.c: New test.
            * gcc.dg/tree-ssa/bitcmp-5.c: New test.
            * gcc.dg/tree-ssa/bitcmp-6.c: New test.