title: Compiler code generation - how we know it is high quality?
body: <p>It is common mantra nowadays: "C/C++ compilers generate better code than hand written assembly." or "Compilers generate code that is as good and often better than could be written by hand."</p>
  
  <p>But how we know this is true? Are there some valuable studies about HLL compiler code quality? I would like to read some works on this subject and not only for C/C++ but for other languages as well.</p>
  
  <p>Thanks</p>
  
  <p><strong>EDIT</strong>: I am asking not for discussion on this subject, nor for personal opinions or thoughts. I am asking about <strong>references</strong> to studies about the subjects. Such studies definitely <strong>must</strong> contains some experimental or theoretical work on the subject that can be verified.</p>
  
  <p>Please, if you don't have such information, simply don't answer this question. I already know all your thoughts on this subject. </p>