# HG changeset patch
# User Gilles Duboscq <duboscq@ssw.jku.at>
# Date 1340722484 -7200
# Node ID f592c22421e7474ff1a3410d306f2393fddb9f81
# Parent  a63ed59939875f79f9bc68d50c6b73e807a95a46
Look for LoopUnswitch opportunities (LoopUnswitch currently disabled)

diff -r a63ed5993987 -r f592c22421e7 graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalOptions.java
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalOptions.java	Tue Jun 26 16:51:48 2012 +0200
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalOptions.java	Tue Jun 26 16:54:44 2012 +0200
@@ -104,6 +104,7 @@
     public static boolean ReassociateInvariants              = true;
     public static boolean FullUnroll                         = true;
     public static int     FullUnrollMaxNodes                 = 150; // TODO (gd) tune
+    public static boolean LoopUnswitch                       = ____;
 
     // debugging settings
     public static int     MethodEndBreakpointGuards          = 0;
diff -r a63ed5993987 -r f592c22421e7 graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/loop/LoopPolicies.java
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/loop/LoopPolicies.java	Tue Jun 26 16:51:48 2012 +0200
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/loop/LoopPolicies.java	Tue Jun 26 16:54:44 2012 +0200
@@ -47,4 +47,9 @@
         int size = Math.max(1, loop.size() - 1 - loop.loopBegin().phis().count());
         return size * exactTrips <= maxNodes;
     }
+
+    public static boolean shouldTryUnswitch(@SuppressWarnings("unused") LoopEx loop) {
+        // TODO (gd) maybe there should be a may number of unswitching per loop
+        return true;
+    }
 }
diff -r a63ed5993987 -r f592c22421e7 graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/LoopTransformLowPhase.java
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/LoopTransformLowPhase.java	Tue Jun 26 16:51:48 2012 +0200
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/LoopTransformLowPhase.java	Tue Jun 26 16:54:44 2012 +0200
@@ -25,9 +25,11 @@
 import com.oracle.graal.compiler.*;
 import com.oracle.graal.compiler.loop.*;
 import com.oracle.graal.debug.*;
+import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 
 public class LoopTransformLowPhase extends Phase {
+    private static final DebugMetric UNSWITCHED = Debug.metric("Unswitched");
 
     @Override
     protected void run(StructuredGraph graph) {
@@ -43,6 +45,28 @@
                     }
                 });
             }
+            if (GraalOptions.LoopUnswitch) {
+                NodeBitMap unswitchedDebug = graph.createNodeBitMap();
+                boolean unswitched;
+                do {
+                    unswitched = false;
+                    final LoopsData dataUnswitch = new LoopsData(graph);
+                    for (LoopEx loop : dataUnswitch.loops()) {
+                        if (LoopPolicies.shouldTryUnswitch(loop)) {
+                            IfNode ifNode = LoopTransformations.findUnswitchableIf(loop);
+                            if (ifNode != null && !unswitchedDebug.isMarked(ifNode)) {
+                                unswitchedDebug.mark(ifNode);
+                                Debug.log("Unswitching %s at %s [%f - %f]", loop, ifNode, ifNode.probability(0), ifNode.probability(1));
+                                //LoopTransformations.unswitch(loop, ifNode);
+                                UNSWITCHED.increment();
+                                //Debug.dump(graph, "After unswitch %s", loop);
+                                unswitched = true;
+                                break;
+                            }
+                        }
+                    }
+                } while(unswitched);
+            }
         }
     }
 }