Merge pull request eclipse-openj9#20420 from a7ehuo/valuetype-fix-null-restricted-array-type-vp

Do not trust nullable arrayclass type in VP

Author: hzongaro

runtime/compiler/optimizer/J9ValuePropagation.cpp

@@ -3782,9 +3782,28 @@ bool J9::ValuePropagation::isUnreliableSignatureType(
       return false;
 
    int32_t numDims = 0;
+   TR_OpaqueClassBlock *originClass = klass;
    klass = comp()->fej9()->getBaseComponentClass(klass, numDims);
+
    if (!TR::Compiler->cls.isInterfaceClass(comp(), klass))
-      return false;
+      {
+      // If the original class is an array class and it is not a null-restricted array,
+      // we can not trust its type as a nullable array because it can either be a nullable
+      // array class type or a null-restricted array type.
+      // TODO-VALUETYPE: However, if in the future Value Propagation constraints are able
+      // to distinguish between nullable and null-restricted arrays, this test can change.
+      if (TR::Compiler->om.areFlattenableValueTypesEnabled() &&
+         (numDims > 0) &&
+         TR::Compiler->cls.isValueTypeClass(klass) &&
+         !TR::Compiler->cls.isArrayNullRestricted(comp(), originClass))
+         {
+         // Do nothing here and will be handled next like an interface array
+         }
+      else
+         {
+         return false;
+         }
+      }
 
    // Find the best array type that we can guarantee based on an
    // array-of-interface signature.

test/functional/Valhalla/playlist.xml

@@ -339,8 +339,7 @@
 			<variation>-Xint</variation>
 			<variation>-Xint -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999</variation>
 			<variation>-Xint -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
-			<!-- https://github.com/eclipse-openj9/openj9/issues/19914 -->
-			<!--<variation>-Xjit:count=0</variation>
+			<variation>-Xjit:count=0</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xgcpolicy:optthruput</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:-EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
@@ -349,17 +348,17 @@
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xnocompressedrefs -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation -Xnocompressedrefs -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
-			<variation>-Xjit:count=1,disableAsyncCompilation -Xnocompressedrefs -Xgcpolicy:gencon</variation>-->
+			<variation>-Xjit:count=1,disableAsyncCompilation -Xnocompressedrefs -Xgcpolicy:gencon</variation>
 			<!-- Test the above options with initialOptLevel=warm -->
-			<!--<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:optthruput</variation>
+			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:optthruput</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:-EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=12 -XX:-EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=99999 -XX:-EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xnocompressedrefs -Xgcpolicy:optthruput -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
 			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xnocompressedrefs -Xgcpolicy:gencon -XX:ValueTypeFlatteningThreshold=99999 -XX:+EnableArrayFlattening</variation>
-			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xnocompressedrefs -Xgcpolicy:gencon</variation>-->
+			<variation>-Xjit:count=1,disableAsyncCompilation,initialOptLevel=warm -Xnocompressedrefs -Xgcpolicy:gencon</variation>
 		</variations>
 		<command>$(JAVA_COMMAND) $(JVM_OPTIONS) \
 		--enable-preview \