[LLVMbugs] [Bug 21377] New: clang hangs on valid code at -Os and above on x86_64-linux-gnu

bugzilla-daemon at llvm.org bugzilla-daemon at llvm.org
Fri Oct 24 19:28:29 PDT 2014


http://llvm.org/bugs/show_bug.cgi?id=21377

            Bug ID: 21377
           Summary: clang hangs on valid code at -Os and above on
                    x86_64-linux-gnu
           Product: clang
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: su at cs.ucdavis.edu
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

The following test case causes the current clang trunk to hang when compiling
at -Os and above in both 32-bit and 64-bit modes on x86_64-linux-gnu.

It also affects all earlier versions of clang and MacOS X. 

$ clang-trunk -v
clang version 3.6.0 (trunk 220587)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.6
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/4.8.1
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
$ 
$ clang-trunk -O1 small.c; a.out
$      
$ timeout -s 9 30 clang-trunk -Os small.c
Killed
$ 
$ time gcc-trunk -Os small.c
0.02user 0.00system 0:00.12elapsed 26%CPU (0avgtext+0avgdata 50752maxresident)k
0inputs+32outputs (1major+6636minor)pagefaults 0swaps
$ 
$ time icc -Os small.c
0.05user 0.06system 0:00.43elapsed 27%CPU (0avgtext+0avgdata 84848maxresident)k
0inputs+240outputs (1major+20231minor)pagefaults 0swaps
$ 
$ time clang-trunk -O1 small.c
0.00user 0.02system 0:00.11elapsed 30%CPU (0avgtext+0avgdata 63872maxresident)k
0inputs+32outputs (1major+6322minor)pagefaults 0swaps
$ 


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


int a, c, d;
unsigned int b;
static int e[1];
long long f;

long long
fn1 ()
{
  return a;
}

void
fn2 ()
{
  int g;
  while (c) 
    {
      f = b;
      g |= f;
      while (c) 
    g = e[0]; 
      g |= fn1 ();
    }
}

int
main ()
{
  fn2 (); 
  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/20141025/9dca4b9b/attachment.html>


More information about the llvm-bugs mailing list