# HG changeset patch
# User Christos Kotselidis <christos.kotselidis@oracle.com>
# Date 1367171443 -7200
# Node ID 365ca8db15a024a586bfb4c930384dd9d117bb81
# Parent  ca4d71edadcd3baa435e142c9e80d42c38aa735c
Add comments in safepoint detection of WriteBarrierVerification Phase

diff -r ca4d71edadcd -r 365ca8db15a0 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierVerificationPhase.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierVerificationPhase.java	Sun Apr 28 19:43:32 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/phases/WriteBarrierVerificationPhase.java	Sun Apr 28 19:50:43 2013 +0200
@@ -99,6 +99,11 @@
     }
 
     private static boolean isSafepoint(Node node) {
+        /*
+         * LoopBegin nodes are also treated as safepoints since a bottom-up analysis is performed
+         * and loop safepoints are placed before LoopEnd nodes. Possible elimination of write
+         * barriers inside loops, derived from writes, outside the loops can not be permitted.
+         */
         return ((node instanceof DeoptimizingNode) && ((DeoptimizingNode) node).canDeoptimize()) || (node instanceof LoopBeginNode);
     }