[llvm-bugs] [Bug 33621] New: wrong code at -Os on x86_64-linux-gnu (in 64-bit mode only) with "-mllvm -enable-newgvn

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=33621

            Bug ID: 33621
           Summary: wrong code at -Os on x86_64-linux-gnu (in 64-bit mode
                    only) with "-mllvm -enable-newgvn
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: su at cs.ucdavis.edu
                CC: llvm-bugs at lists.llvm.org

It might be a(nother) dupe.  

$ clang -v
clang version 5.0.0 (trunk 306403)
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 -Os small.c; ./a.out
$ 
$ clang -Os -mllvm -enable-newgvn small.c
$ timeout -s 9 5 ./a.out
Killed
$ 


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


int a, b, c, d = 1, e;

void fn1 ()
{
  int g;
  if (!a)
    goto L1;
  int i = ~a;
  if (i)
    {
      i = a;
    L2:
      c = 0;
    L1:
      g = ~(a | i);
      if (!g)
        goto L2;
    }
  c = e = b = i;
  g = a && g;
  c = -((e || b) + g - d);
  int k = ~(c | e);
  while (k)
    ;
}

int main ()
{
  a = 1;
  fn1 ();
  return 0; 
}

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