[llvm-bugs] [Bug 39498] New: wrong code at -O3 on x86_64-linux-gnu (generated code hangs)

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=39498

            Bug ID: 39498
           Summary: wrong code at -O3 on x86_64-linux-gnu (generated code
                    hangs)
           Product: clang
           Version: unspecified
          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, richard-llvm at metafoo.co.uk

Tested with trunk revision 345488. 

$ clangpolly -v
clang version 8.0.0 (http://llvm.org/git/clang.git
8029b38886dd239769e3501dac21438e16886ce8) (llvm/trunk 345488)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/su/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.4
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.3.0
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/4.7.3
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/4.9.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.2.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$ 
$ clangpolly -O2 -w small.c; ./a.out
$ 
$ clangpolly -O3 -w small.c
$ timeout -s 9 5 ./a.out
Killed
$ 


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


int a, b, c;

int main ()
{
  int e = 7;
  while (1)
    {
      int f = 2, g = 1, h = 126, *i = &h;
      &a == i;
    L1:
    L2:
      if (!h)
        goto L1;
      if (!f)
        {
          c = (g << h) || (c << 3);
          goto L2;
        }
      b = e;
      f = h = e = g;
      g = b;
      if (b)
        break;
      goto L2;
    }
  return 0;
}

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20181030/1c6d9353/attachment.html>