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From: "dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/109031] csmith: possible bad code with -O2
 -fno-strict-aliasing
Date: Wed, 08 Mar 2023 16:45:11 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109031

--- Comment #17 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Martin Li=C5=A1ka from comment #16)
> bash -x qwe.sh bug892.c

That's a really useful tip. Thanks. I've debugged the script some more
and now have:

rm -f 1 2 one.exe two.exe
/usr/bin/gcc -w -Werror=3Dimplicit bug892.c -o one.exe \
    && (./one.exe 1 | fgrep "checksum after hashing g_50 :" > 1)
    if test $? !=3D 0;
    then
        exit 1
    fi
    # So we have a checksum in file 1.
    /home/dcb36/gcc/results/bin/gcc -w -O2 -fno-strict-aliasing bug892.c  -o
two.exe \
    && (./two.exe 1 | fgrep "checksum after hashing g_50 :" > 2)
    if test $? !=3D 0;
    then
         exit 1
    fi
    # And we have a checksum in file 2.
    diff 1 2
    if test $? =3D 0; then
        exit 1
    fi
    exit 0

This script appears to be running nicely now. I will report back
when it has finished or made significant progress.=