[Bug target/99988] aarch64: GCC generates excessive consecutive bti j instructions

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99988

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Alex Coplan
<acoplan@gcc.gnu.org>:

https://gcc.gnu.org/g:419c243dfb9aba51aceb1370a241db082847eeb5

commit r10-9818-g419c243dfb9aba51aceb1370a241db082847eeb5
Author: Alex Coplan <alex.coplan@arm.com>
Date:   Wed Apr 21 14:42:04 2021 +0100

    aarch64: Avoid duplicating bti j insns for jump tables [PR99988]

    This patch fixes PR99988 which shows us generating large (> 250)
    sequences of back-to-back bti j instructions.

    The fix is simply to avoid inserting bti j instructions at the target of
    a jump table if we've already inserted one for a given label.

    Co-Authored-By: Christophe Lyon <clyon@gcc.gnu.org>

    gcc/ChangeLog:

            PR target/99988
            * config/aarch64/aarch64-bti-insert.c (aarch64_bti_j_insn_p): New.
            (rest_of_insert_bti): Avoid inserting duplicate bti j insns for
            jump table targets.

    gcc/testsuite/ChangeLog:

            PR target/99988
            * gcc.target/aarch64/pr99988.c: New test.

    (cherry picked from commit 1011bb8bc67cf34c45a9237d72a801a14ad9ef0f)