title: Why C compiler validation suites themselves may use the C standard library if the C standard library is actually under test?
body: <p>How it is possible for C compiler validation suites to use any feature of the C standard library if the C standard library is actually under test and may be buggy (which invalidates the validation suite itself)?</p>
  <p>For example, the suite may use itself <code>memset</code>, <code>fopen</code>, etc., but <code>memset</code>, <code>fopen</code>, etc. are actually under test and may be buggy.</p>
  <p>Confused. Clarification / experience is needed.</p>
  <p>UPD. Clarified after examining suite's source code. The suite uses two compilers:</p>
  <ol>
  <li>Reference compiler is used to build the suite itself.</li>
  <li>IUT (Implementation Under Test) compiler is used to run tests on it.</li>
  </ol>