comment out CompilerOpaqueUse
diff --git a/demos/fill_speed.cc b/demos/fill_speed.cc
index 5e2812a..c1489cd 100644
--- a/demos/fill_speed.cc
+++ b/demos/fill_speed.cc
@@ -25,7 +25,8 @@
 SAFESIDE_NEVER_INLINE
 void Fill(int* buffer, int size, int val) {
   std::fill(buffer, buffer + size, val);
-  CompilerOpaqueUse(buffer);
+  // seems unnecessary
+  // CompilerOpaqueUse(buffer);
 }
 
 Clock::duration TestOne(int* buffer, int size, int val) {