From 5242df175673dffedb99b87f676206d5b647d6ab Mon Sep 17 00:00:00 2001
From: Abdulrahman Alattas <rmnattas@gmail.com>
Date: Fri, 21 Jun 2024 10:22:50 -0400
Subject: [PATCH] Add offHeapCopyMemory in VP DelayedTransformations

---
 compiler/optimizer/OMRValuePropagation.cpp    | 16 ++++++++++++++++
 compiler/optimizer/OMRValuePropagation.hpp    |  1 +
 compiler/optimizer/ValuePropagationCommon.cpp |  1 +
 3 files changed, 18 insertions(+)

diff --git a/compiler/optimizer/OMRValuePropagation.cpp b/compiler/optimizer/OMRValuePropagation.cpp
index 24fe9d382f8..6dbf92f7707 100644
--- a/compiler/optimizer/OMRValuePropagation.cpp
+++ b/compiler/optimizer/OMRValuePropagation.cpp
@@ -7264,6 +7264,22 @@ void OMR::ValuePropagation::doDelayedTransformations()
       }
    _scalarizedArrayCopies.deleteAll();
 
+#if defined(J9_PROJECT_SPECIFIC) && defined(OMR_GC_SPARSE_HEAP_ALLOCATION)
+   // Transform Unsafe.copyMemory in OffHeap
+   if (TR::Compiler->om.isOffHeapAllocationEnabled())
+      {
+      ListIterator<TR_TreeTopNodePair> copyMemoryIt(&_offHeapCopyMemory);
+      TR_TreeTopNodePair *copyMemoryPair;
+      for (copyMemoryPair = copyMemoryIt.getFirst();
+         copyMemoryPair; copyMemoryPair = copyMemoryIt.getNext())
+         {
+         if (performTransformation(comp(), "O^O Call arraycopy instead of Unsafe.copyMemory: %p\n", copyMemoryPair->_node))
+            TR::TransformUtil::transformUnsafeCopyMemorytoArrayCopyForOffHeap(self()->comp(), copyMemoryPair->_treetop, copyMemoryPair->_node);
+         }
+      _offHeapCopyMemory.deleteAll();
+      }
+#endif
+
    // NOTE: the array copy spine checks are processed before the reference, realtime, and
    //       unknown arraycopies because it refactors the CFG at a higher (outer) level
    //       than the others.  To simplify the CFG it should be run first.
diff --git a/compiler/optimizer/OMRValuePropagation.hpp b/compiler/optimizer/OMRValuePropagation.hpp
index edb077d2b94..0b0276eecec 100644
--- a/compiler/optimizer/OMRValuePropagation.hpp
+++ b/compiler/optimizer/OMRValuePropagation.hpp
@@ -994,6 +994,7 @@ class ValuePropagation : public TR::Optimization
    List<TR_ArrayCopySpineCheck> _arrayCopySpineCheck;
    List<TR::TreeTop> _multiLeafCallsToInline;
    List<TR_TreeTopNodePair> _scalarizedArrayCopies;
+   List<TR_TreeTopNodePair> _offHeapCopyMemory;
    List<TR::TreeTop> _converterCalls;
    List<TR::TreeTop> _objectCloneCalls;
    List<TR::TreeTop> _arrayCloneCalls;
diff --git a/compiler/optimizer/ValuePropagationCommon.cpp b/compiler/optimizer/ValuePropagationCommon.cpp
index d29f095ff30..db72db85811 100644
--- a/compiler/optimizer/ValuePropagationCommon.cpp
+++ b/compiler/optimizer/ValuePropagationCommon.cpp
@@ -120,6 +120,7 @@ OMR::ValuePropagation::ValuePropagation(TR::OptimizationManager *manager)
      _javaLangClassGetComponentTypeCalls(trMemory()),
      _unknownTypeArrayCopyTrees(trMemory()),
      _scalarizedArrayCopies(trMemory()),
+     _offHeapCopyMemory(trMemory()),
      _predictedThrows(trMemory()),
      _prexClasses(trMemory()),
      _prexMethods(trMemory()),