[llvm-bugs] [Bug 28655] New: wrong code (SIGFPE) at -O3 on x86_64-linux-gnu (in both 32-bit and 64-bit modes)

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=28655

            Bug ID: 28655
           Summary: wrong code (SIGFPE) at -O3 on x86_64-linux-gnu (in
                    both 32-bit and 64-bit modes)
           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: llvm-bugs at lists.llvm.org
    Classification: Unclassified

The following code is miscompiled by the current clang trunk at -O3 on
x86_64-linux-gnu in both the 32-bit and 64-bit modes.

This is a regression from 3.8.x.  


$ clang -v
clang version 4.0.0 (trunk 276243)
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/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.3
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/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.1.1
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
$
$ clang -O2 small.c; ./a.out
$ clang-3.8 -O3 small.c; ./a.out
$
$ clang -O3 small.c
$ ./a.out
Floating point exception (core dumped)
$


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


int printf (const char *, ...);

int a, b, c, g = 11, h = 1, j, k;
static int e = 3, f;

int fn1 ()
{ 
  int i = 0;
  for (; i < 3; i++)
    if (k)
      printf ("%d %d %d\n", e, f, i);
  f = 1;
  return 0;
}

int fn2 (int p1)
{ 
  a || fn1 ();
  e = c || 1;
  return p1;
}

int main ()
{ 
  int l = a = 1;
  for (; a; a--)
    {
    L1:
      j = fn2 (l);
      b = 2;
    }
  int n = 1 % (g & b) | 15;
  if (h)
    { 
      g = ~n;
      if (1 < e)
        goto L1;
    }
  l--;
  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/20160721/aa4c5a2f/attachment.html>