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changeset 15875:2d5f9c7379c1

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Propagate 0.0 probabilities when simplifying IfNode.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Tue, 13 May 2014 02:31:20 +0200
parents 62738ce98804
children 8df3b6d4a035
files graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java
diffstat 1 files changed, 46 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Mon May 12 11:43:36 2014 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Tue May 13 02:31:20 2014 +0200
@@ -27,6 +27,7 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.api.meta.JavaTypeProfile.ProfiledType;
 import com.oracle.graal.api.meta.ProfilingInfo.TriState;
+import com.oracle.graal.compiler.common.*;
 import com.oracle.graal.compiler.common.calc.*;
 import com.oracle.graal.compiler.common.type.*;
 import com.oracle.graal.debug.*;
@@ -599,6 +600,18 @@
         connectEnds(falseEnds, phiValues, oldFalseSuccessor, merge, tool);
         connectEnds(trueEnds, phiValues, oldTrueSuccessor, merge, tool);
 
+        if (this.trueSuccessorProbability == 0.0) {
+            for (AbstractEndNode endNode : trueEnds) {
+                propagateZeroProbability(endNode);
+            }
+        }
+
+        if (this.trueSuccessorProbability == 1.0) {
+            for (AbstractEndNode endNode : falseEnds) {
+                propagateZeroProbability(endNode);
+            }
+        }
+
         /*
          * Remove obsolete ends only after processing all ends, otherwise oldTrueSuccessor or
          * oldFalseSuccessor might have been removed if it is a LoopExitNode.
@@ -620,6 +633,39 @@
         return true;
     }
 
+    private void propagateZeroProbability(FixedNode startNode) {
+        Node prev = null;
+        for (FixedNode node : GraphUtil.predecessorIterable(startNode)) {
+            if (node instanceof IfNode) {
+                IfNode ifNode = (IfNode) node;
+                if (ifNode.trueSuccessor() == prev) {
+                    if (ifNode.trueSuccessorProbability == 0.0) {
+                        return;
+                    } else if (ifNode.trueSuccessorProbability == 1.0) {
+                        propagateZeroProbability((FixedNode) ifNode.predecessor());
+                    } else {
+                        ifNode.setTrueSuccessorProbability(0.0);
+                    }
+                } else if (ifNode.falseSuccessor() == prev) {
+                    if (ifNode.trueSuccessorProbability == 1.0) {
+                        return;
+                    } else if (ifNode.trueSuccessorProbability == 0.0) {
+                        propagateZeroProbability((FixedNode) ifNode.predecessor());
+                    } else {
+                        ifNode.setTrueSuccessorProbability(1.0);
+                    }
+                } else {
+                    throw new GraalInternalError("Illegal state");
+                }
+            } else if (node instanceof MergeNode) {
+                for (AbstractEndNode endNode : ((MergeNode) node).cfgPredecessors()) {
+                    propagateZeroProbability(endNode);
+                }
+            }
+            prev = node;
+        }
+    }
+
     private static boolean checkFrameState(FixedNode start) {
         FixedNode node = start;
         while (true) {