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From: "shaohua.li at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/111648] New: Wrong code at -O2/3 on
 x86_64-linux-gnu since r14-3243-ga7dba4a1c05
Date: Sat, 30 Sep 2023 14:04:21 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: wrong-code
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X-Bugzilla-Who: shaohua.li at inf dot ethz.ch
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111648

            Bug ID: 111648
           Summary: Wrong code at -O2/3 on x86_64-linux-gnu since
                    r14-3243-ga7dba4a1c05
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: shaohua.li at inf dot ethz.ch
                CC: prathamesh3492 at gcc dot gnu.org
  Target Milestone: ---

gcc at -O2/3 produced the wrong code

Bisected to r14-3243-ga7dba4a1c05

Compiler explorer: https://godbolt.org/z/1bvWTrEK1

$ cat a.c
int printf(const char *, ...);
int a;
int *b =3D &a;
static int **c =3D &b;
static int d;
short e;
char f;
int main() {
  f =3D -21;
  for (; f < -5; f++) {
    e =3D f ^ 3;
    d =3D *b;
    **c =3D e;
  }
  printf("%d\n", d);
}
$
$ gcc -O0 a.c && ./a.out
-6
$ gcc -O2 a.c && ./a.out
2
$=