title: How to get gVim's vimdiff to ignore case?
body: <p>I am trying to compare two assembly files where one was written all caps and the other in lowercase. Many lines are identical up to case and whitespace.</p>
  
  <p>I tried the following, while two buffers in diff mode:</p>
  
  <pre><code>:set diffopt+=icase
  :set diffopt+=iwhite
  :diffupdate
  </code></pre>
  
  <p>The whitespace thing seems to work well, but the ignore case does not do its work. For example, in the following two lines:</p>
  
  <pre><code>            I0=R0;              // ADDRESS OF INPUT ARRAY
  
      i0 = r0;            // address of input array
  </code></pre>
  
  <p>[the first line begins with 12 spaces, the second with a single tab]</p>
  
  <p>Why? What can I do?</p>
  
  <p>UPDATE: just noticed that in these two lines all differences were ignored OK:</p>
  
  <pre><code>                                // MULTIPLY R1 BY 4 TO FETCH DATA OF WORD LENGTH
                          // multiply r1 by 4 to fetch data of word length
  </code></pre>