# HG changeset patch
# User Lukas Stadler <lukas.stadler@oracle.com>
# Date 1400760295 -7200
# Node ID 9e172511971d6acbe1743d8474c71d0c1317d64c
# Parent  399aa56c636645f6400ac69ae8666f077cae62f1
make FixedNodeProbabilityCache behave better in the presence of dead code

diff -r 399aa56c6366 -r 9e172511971d graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/FixedNodeProbabilityCache.java
--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/FixedNodeProbabilityCache.java	Thu May 22 13:19:47 2014 +0200
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/FixedNodeProbabilityCache.java	Thu May 22 14:04:55 2014 +0200
@@ -42,10 +42,14 @@
     private final Map<FixedNode, Double> cache = newIdentityMap();
 
     public double applyAsDouble(FixedNode node) {
+        assert node != null;
         metricComputeNodeProbability.increment();
 
         FixedNode current = node;
         while (true) {
+            if (current == null) {
+                return 1D;
+            }
             Node predecessor = current.predecessor();
             if (current instanceof BeginNode) {
                 if (predecessor == null) {
@@ -54,6 +58,9 @@
                     assert predecessor instanceof ControlSplitNode : "a FixedNode with multiple successors needs to be a ControlSplitNode: " + current + " / " + predecessor;
                     break;
                 }
+            } else if (predecessor == null) {
+                // this should only appear for dead code
+                return 1D;
             }
             current = (FixedNode) predecessor;
         }
@@ -70,10 +77,8 @@
                 if (current instanceof LoopBeginNode) {
                     probability *= ((LoopBeginNode) current).loopFrequency();
                 }
-            } else if (current instanceof StartNode) {
-                probability = 1D;
             } else {
-                // this should only appear for dead code
+                assert current instanceof StartNode;
                 probability = 1D;
             }
         } else {