Merge pull request #7430 from jdmpapin/mustBeNotEqual-off

Reinstate original VPClass::mustBeNotEqual() logic temporarily

compiler/optimizer/VPConstraint.cpp

@@ -5122,6 +5122,31 @@ bool TR::VPClass::mustBeNotEqual(TR::VPConstraint *other, OMR::ValuePropagation
    if (isNonNullObject() && other->isNullObject())
       return true;
 
+   // The new logic below is causing some test failures that need to be investigated.
+   // This original logic is reinstated in the meantime.
+   if (getKnownObject() && other->getKnownObject() && isNonNullObject() && other->isNonNullObject())
+      return getKnownObject()->getIndex() != other->getKnownObject()->getIndex();
+
+   TR::VPClass *otherClass = NULL;
+   if (other)
+      otherClass = other->asClass();
+  if (!_preexistence &&
+       !_arrayInfo && _type &&
+       _type->isFixedClass() && isNonNullObject() &&
+       other && otherClass &&
+       !otherClass->getArrayInfo() &&
+       !otherClass->isPreexistentObject() &&
+       otherClass->getClassType() && otherClass->getClassType()->isFixedClass() && otherClass->isNonNullObject() &&
+       (isClassObject() == TR_yes) &&
+       (other->isClassObject() == TR_yes))
+      {
+      if (_type->asFixedClass()->getClass() != otherClass->getClassType()->asFixedClass()->getClass())
+         return true;
+      }
+
+   return false;
+
+#if 0
    if (!isNonNullObject() && !other->isNonNullObject())
       return false; // both could be null
 
@@ -5285,6 +5310,7 @@ bool TR::VPClass::mustBeNotEqual(TR::VPConstraint *other, OMR::ValuePropagation
    // Two unrelated non-interface classes can't have a common subtype.
    return vp->fe()->isInstanceOf(thisClass, otherClass, true, true) != TR_yes
       && vp->fe()->isInstanceOf(otherClass, thisClass, true, true) != TR_yes;
+#endif
    }
 
 bool TR::VPNullObject::mustBeNotEqual(TR::VPConstraint *other, OMR::ValuePropagation *vp)