[llvm-bugs] [Bug 33351] New: wrong code at -O1 and above in CFLAA on x86_64-linux-gnu (with "-mllvm -use-cfl-aa=anders", but not "-mllvm -use-cfl-aa=steens")

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=33351

            Bug ID: 33351
           Summary: wrong code at -O1 and above in CFLAA on
                    x86_64-linux-gnu (with "-mllvm -use-cfl-aa=anders",
                    but not "-mllvm -use-cfl-aa=steens")
           Product: clang
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: su at cs.ucdavis.edu
                CC: llvm-bugs at lists.llvm.org

It affects 3.9.x and later. 

$ clang -v
clang version 5.0.0 (trunk 304931)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-trunk/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.0.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$ 
$ clang -O1 -w small.c; ./a.out 
$ clang -O1 -mllvm -use-cfl-aa=steens -w small.c; ./a.out
$ 
$ clang -O1 -mllvm -use-cfl-aa=anders -w small.c
$ ./a.out
a.out: small.c:25: fn1: Assertion `j' failed.
Aborted (core dumped)
$ 


----------------------------------------------------------------------------


void __assert_fail (const char *, const char *, unsigned int, const char *);

int a, b, *c = &b, *d = &b;
static int e = 1;

void fn1 ()
{
  unsigned char g;
  if (a)
    {
      e = 0;
      goto L;
    }
  int *l, **i = &l;
  g = b - 1;
  for (; b < 1; b = g)
    {
    L:
      *c = 0;
      a % e ^ 0;
      for (; a < 1; a++)
        {
          int j[3] = { 1 }, k[3] = { 1 };
          *i = d;
          l ? (void) 0 : __assert_fail ("j", "small.c", 25, "fn1");
        }
    }
}

int main ()
{
  fn1 ();
  return 0; 
}

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