[llvm-commits] CVS: llvm/docs/FAQ.html

Chris Lattner lattner at cs.uiuc.edu
Tue Dec 16 16:35:02 PST 2003


Changes in directory llvm/docs:

FAQ.html updated: 1.15 -> 1.16

---
Log message:

Add a faq entry for the demo page


---
Diffs of the changes:  (+24 -6)

Index: llvm/docs/FAQ.html
diff -u llvm/docs/FAQ.html:1.15 llvm/docs/FAQ.html:1.16
--- llvm/docs/FAQ.html:1.15	Mon Dec  8 00:22:05 2003
+++ llvm/docs/FAQ.html	Tue Dec 16 16:33:55 2003
@@ -70,6 +70,7 @@
   <ol>
      <li>What is this <tt>__main()</tt> call that gets inserted into
          <tt>main()</tt>?</li>
+     <li>Where did all of my code go??</li>
   </ol>
   </li>
 </ol>
@@ -406,11 +407,9 @@
   <a name="cfe_code">Questions about code generated by the GCC front-end</a>
 </div>
 
-<div class="question">
-<p>
+<div class="question"><p>
 What is this <tt>__main()</tt> call that gets inserted into <tt>main()</tt>?
-</p>
-</div>
+</p></div>
 
 <div class="answer">
 <p>
@@ -426,10 +425,29 @@
 <tt>llvm/runtime/GCCLibraries/crtend/</tt> directory in the source-base, and is
 linked in automatically when you link the program.
 </p>
-
 </div>
 
+<!--=========================================================================-->
+
+<div class="question"><p>
+Where did all of my code go??
+</p></div>
 
+<div class="answer">
+<p>
+If you are using the LLVM demo page, you may often wonder what happened to all
+of the code that you typed in.  Remember that the demo script is running the
+code through the LLVM optimizers, so if you code doesn't actually do anything
+useful, it might all be deleted.
+</p>
+
+<p>
+To prevent this, make sure that the code is actually needed.  For example, if
+you are computing some expression, return the value from the function instead of
+leaving it in a local variable.  If you really want to constrain the optimizer,
+you can read from and assign to <tt>volatile</tt> global variables.
+</p>
+</div>
 
 <!-- *********************************************************************** -->
 <!-- *********************************************************************** -->
@@ -438,7 +456,7 @@
 <div class="doc_footer">
   <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a>
   <br>
-  Last modified: $Date: 2003/12/08 06:22:05 $
+  Last modified: $Date: 2003/12/16 22:33:55 $
 </div>
 
 </body>





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