[LLVMbugs] [Bug 19799] New: wrong code (hangs) at -Os and above on x86_64-linux-gnu (affecting trunk, but not 3.4 or earlier)

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=19799

            Bug ID: 19799
           Summary: wrong code (hangs) at -Os and above on
                    x86_64-linux-gnu (affecting trunk, but not 3.4 or
                    earlier)
           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 code is miscompiled by the current clang trunk on
x86_64-linux-gnu at -Os and above in both 32-bit and 64-bit modes. 

It is a regression from 3.4.   

$ clang-trunk -v
clang version 3.5.0 (trunk 209121)
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
$ clang-3.4 -Os small.c; a.out
$ 
$ clang-trunk -Os small.c
$ timeout -s 9 10 ./a.out
Killed
$ 


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


int a;

int
foo (int p1, int p2)
{
  return p1 + p2;
}

int
bar ()
{
  for (a = -1; a < 2; a = foo (a, 2))
    if (!a)
      return 0;
  return 1;
}

int
main ()
{
  bar ();
  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/20140519/185316a8/attachment.html>