title: Can branch prediction cause illegal instruction?
body: <p>In the following pseudo-code:</p>
  
  <pre><code>if (rdtscp supported by hardware) {
      Invoke "rdtscp" instruction
  } else {
      Invoke "rdtsc" instruction
  }
  </code></pre>
  
  <p>Let's say the CPU does not support the <code>rdtscp</code> instruction and so we fallback to the else statement.</p>
  
  <p>If CPU mispredicts the branch, is it possible for the instruction pipeline to try to execute <code>rdtscp</code> and throw an <code>Illgal Instruction</code> error?</p>