[Bug gas/30279] UBSAN error: /buildworker/marxinbox-cross-binutils-sanitizers/build/gas/config/tc-m68hc11.c:708:20

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30279

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot 
gnu.org> ---
The master branch has been updated by Alan Modra <amodra@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c61b7b7b8ea5e3a55b4642dade4798e5c896df66

commit c61b7b7b8ea5e3a55b4642dade4798e5c896df66
Author: Alan Modra <amodra@gmail.com>
Date:   Tue Mar 28 20:25:26 2023 +1030

    Avoid undefined behaviour in m68hc11 md_begin

    Given p = A where p is a pointer to some type and A is an array of
    that type, then the expression p - 1 + 1 evokes undefined behaviour
    according to the C standard.

    gcc-13 -fsanitize=address,undefined complains about this, but not
    where the undefined behaviour actually occurs at tc-m68hc11.c:646.
    Instead you get an error: "tc-m68hc11.c:708:20: runtime error: store
    to address 0x62600000016c with insufficient space for an object of
    type 'int'".  Which is a lie.  There most definitely is space there.
    Oh well, diagnostics are sometimes hard to get right.  The UB is easy
    to avoid.

            PR 30279
            * config/tc-m68hc11.c (md_begin): Avoid undefined pointer
            decrement.  Remove unnecessary cast.

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