<html>
    <head>
      <base href="https://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - SSE compare float to integer _mm_comige_ss family of instructions has changed behavior"
   href="https://llvm.org/bugs/show_bug.cgi?id=28510">28510</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>SSE compare float to integer _mm_comige_ss family of instructions has changed behavior
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Windows NT
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>-New Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>jujjyl@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>STR:

#include <xmmintrin.h>
#include <math.h>
#include <stdio.h>

int main()
{
    __m128 a = _mm_set1_ps(42.f);
    __m128 b = _mm_set1_ps(NAN);

    int equal = _mm_comieq_ss(a, b);
    printf("equal: %d\n", equal);
}

Clang/LLVM <= 3.8, GCCs and Visual Studios will print "equal: 1" as expected
(although unintuitive), but the current Clang trunk will print "equal: 0"
instead.

We are currently discussing this change in behavior in
<a href="https://github.com/kripken/emscripten/issues/4435">https://github.com/kripken/emscripten/issues/4435</a> as well.</pre>
        </div>
      </p>
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