# HG changeset patch
# User Erik Eckstein <erik.eckstein@oracle.com>
# Date 1400582337 -7200
# Node ID 6a6cb7f2db907fb797e49874a85394676071b2da
# Parent  bdf260d8e1639c9e0b8da7e6d444b988defc91b2
fix wrong handling of memory anti-dependencies in scheduler

diff -r bdf260d8e163 -r 6a6cb7f2db90 graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/MemoryScheduleTest.java
--- a/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/MemoryScheduleTest.java	Mon May 19 17:21:30 2014 -0700
+++ b/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/MemoryScheduleTest.java	Tue May 20 12:38:57 2014 +0200
@@ -374,6 +374,30 @@
         assertReadAndWriteInSameBlock(schedule, false);
     }
 
+    public static int testAntiDependencySnippet(int a) {
+        /*
+         * This read must not be scheduled after the following write.
+         */
+        int res = container.a;
+        container.a = 10;
+
+        /*
+         * Add some more basic blocks.
+         */
+        if (a < 0) {
+            container.b = 20;
+        }
+        container.c = 30;
+        return res;
+    }
+
+    @Test
+    public void testAntiDependency() {
+        SchedulePhase schedule = getFinalSchedule("testAntiDependencySnippet", TestMode.WITHOUT_FRAMESTATES);
+        assertDeepEquals(4, schedule.getCFG().getBlocks().size());
+        assertReadBeforeAllWritesInStartBlock(schedule);
+    }
+
     /**
      * testing scheduling within a block.
      */
@@ -574,6 +598,20 @@
         assertTrue(!(inSame ^ schedule.getCFG().blockFor(read) == schedule.getCFG().blockFor(write)));
     }
 
+    private static void assertReadBeforeAllWritesInStartBlock(SchedulePhase schedule) {
+        boolean writeNodeFound = false;
+        boolean readNodeFound = false;
+        for (Node node : schedule.nodesFor(schedule.getCFG().getStartBlock())) {
+            if (node instanceof FloatingReadNode) {
+                assertTrue(!writeNodeFound);
+                readNodeFound = true;
+            } else if (node instanceof WriteNode) {
+                writeNodeFound = true;
+            }
+        }
+        assertTrue(readNodeFound);
+    }
+
     private SchedulePhase getFinalSchedule(final String snippet, final TestMode mode) {
         return getFinalSchedule(snippet, mode, MemoryScheduling.OPTIMAL);
     }
diff -r bdf260d8e163 -r 6a6cb7f2db90 graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java
--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java	Mon May 19 17:21:30 2014 -0700
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/schedule/SchedulePhase.java	Tue May 20 12:38:57 2014 +0200
@@ -235,18 +235,17 @@
             if (!foundExcludeNode && node == excludeNode) {
                 foundExcludeNode = true;
             }
-            if (node == startNode) {
-                continue;
+            if (node != startNode) {
+                if (node instanceof MemoryCheckpoint.Single) {
+                    LocationIdentity identity = ((MemoryCheckpoint.Single) node).getLocationIdentity();
+                    accm.add(identity);
+                } else if (node instanceof MemoryCheckpoint.Multi) {
+                    for (LocationIdentity identity : ((MemoryCheckpoint.Multi) node).getLocationIdentities()) {
+                        accm.add(identity);
+                    }
+                }
+                assert MemoryCheckpoint.TypeAssertion.correctType(node);
             }
-            if (node instanceof MemoryCheckpoint.Single) {
-                LocationIdentity identity = ((MemoryCheckpoint.Single) node).getLocationIdentity();
-                accm.add(identity);
-            } else if (node instanceof MemoryCheckpoint.Multi) {
-                for (LocationIdentity identity : ((MemoryCheckpoint.Multi) node).getLocationIdentities()) {
-                    accm.add(identity);
-                }
-            }
-            assert MemoryCheckpoint.TypeAssertion.correctType(node);
 
             if (foundExcludeNode) {
                 accm = set;