[LLVMbugs] [Bug 17076] New: wrong code (SIGFPE) at -O3 on x86_64-linux-gnu (both 32-bit and 64-bit modes)

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=17076

            Bug ID: 17076
           Summary: wrong code (SIGFPE) at -O3 on x86_64-linux-gnu (both
                    32-bit and 64-bit modes)
           Product: clang
           Version: unspecified
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: LLVM Codegen
          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 current clang trunk (as well as clang 3.2
and 3.3) on x86_64-linux-gnu at -O3 (in both 32-bit and 64-bit modes),
resulting in a SIGFPE. 

It may be related to 17073, but this one also fails for 64-bit mode. 

$ clang-trunk -v
clang version 3.4 (trunk 189735)
$ clang-trunk -O2 small.c
$ a.out
$ clang-trunk -O3 small.c
$ a.out
Floating point exception (core dumped)
$ clang-3.3 -O3 small.c
$ a.out
Floating point exception (core dumped)
$ clang-3.2 -O3 small.c
$ a.out
Floating point exception (core dumped)
$ 



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


int printf (const char *, ...);
volatile int a, j, m, n;
int b, c, d, e, g, h, *i, k;
unsigned short f;

void foo ()
{
  for (; c > -19; c--)
    for (b = 0; b < 1; b++)
      {
    short l = a;
    k = j = g | (0 <= (h |= 1));
    l = f == 0 ? 1 : 1 / f;
    e = ~(l + c);
    for (d = 0; d; d = 1)
      *i = 0;
      }
}

int main ()
{
  int o = 0;
  if (n)
    o = 1;
  foo ();
  for (; m; m++)
    if (o)
      printf ("%d\n", 0);
  return 0;
}

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