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    <head>
      <base href="https://bugs.llvm.org/">
    </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 - Signaling NaNs are seem supported but __SUPPORT_SNAN__ is not defined"
   href="https://bugs.llvm.org/show_bug.cgi?id=52577">52577</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Signaling NaNs are seem supported but __SUPPORT_SNAN__ is not defined
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>13.0
          </td>
        </tr>

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

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

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

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>C
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>pavel.morozkin@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Note: this may not be a bug, but the subject needs a clarification.

This code:
#define _WANT_SNAN
#ifdef __SUPPORT_SNAN__
#pragma message "__SUPPORT_SNAN__ is defined"
#else
#pragma message "__SUPPORT_SNAN__ is not defined"
#endif

compiled with:
$ clang -std=c11 -pedantic -Wall -Wextra -ffp-model=strict -c

leads to:
<source>:5:9: warning: __SUPPORT_SNAN__ is not defined [-W#pragma-messages]

However, according to some tests signaling NaNs are supported.

Then what is the real reason to not define __SUPPORT_SNAN__?

It may be useful to mention the status of support of signaling NaNs in User's
Manual: <a href="https://clang.llvm.org/docs/UsersManual.html">https://clang.llvm.org/docs/UsersManual.html</a>.

Version: clang 13.0.0 on x86_64 on Linux</pre>
        </div>
      </p>


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