*** old/src/hotspot/share/runtime/arguments.cpp	Tue Mar 12 10:52:35 2019
--- new/src/hotspot/share/runtime/arguments.cpp	Tue Mar 12 10:52:34 2019

*** 1606,1623 ****
--- 1606,1618 ----
  
    LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
    NOT_LP64(ShouldNotReachHere(); return 0);
  }
  
! void Arguments::set_use_compressed_oops(size_t max_heap_size) {
  #ifndef ZERO
  #ifdef _LP64
    // MaxHeapSize is not set up properly at this point, but
    // the only value that can override MaxHeapSize if we are
    // to use UseCompressedOops is InitialHeapSize.
    size_t max_heap_size = MAX2(MaxHeapSize, InitialHeapSize);
  
    if (max_heap_size <= max_heap_for_compressed_oops()) {
  #if !defined(COMPILER1) || defined(TIERED)
      if (FLAG_IS_DEFAULT(UseCompressedOops)) {
        FLAG_SET_ERGO(bool, UseCompressedOops, true);
      }

*** 1677,1699 ****
--- 1672,1681 ----
  jint Arguments::set_ergonomics_flags() {
    GCConfig::initialize();
  
    set_conservative_max_heap_alignment();
  
  #ifndef ZERO
  #ifdef _LP64
    set_use_compressed_oops();
  
    // set_use_compressed_klass_ptrs() must be called after calling
    // set_use_compressed_oops().
    set_use_compressed_klass_ptrs();
  
    // Also checks that certain machines are slower with compressed oops
    // in vm_version initialization code.
  #endif // _LP64
  #endif // !ZERO
  
    return JNI_OK;
  }
  
  julong Arguments::limit_by_allocatable_memory(julong limit) {
    julong max_allocatable;

*** 1742,1751 ****
--- 1724,1738 ----
  
      if (!FLAG_IS_DEFAULT(ErgoHeapSizeLimit) && ErgoHeapSizeLimit != 0) {
        // Limit the heap size to ErgoHeapSizeLimit
        reasonable_max = MIN2(reasonable_max, (julong)ErgoHeapSizeLimit);
      }
+ 
+     // Now that we have a more accurate MaxHeapSize, see if we can 
+     // enable compressed oops.  
+     set_use_compressed_oops(MAX2(reasonable_max, InitialHeapSize));
+ 
      if (UseCompressedOops) {
        // Limit the heap size to the maximum possible when using compressed oops
        julong max_coop_heap = (julong)max_heap_for_compressed_oops();
  
        // HeapBaseMinAddress can be greater than default but not less than.

*** 1778,1787 ****
--- 1765,1777 ----
        reasonable_max = MAX2(reasonable_max, (julong)InitialHeapSize);
      }
  
      log_trace(gc, heap)("  Maximum heap size " SIZE_FORMAT, (size_t) reasonable_max);
      FLAG_SET_ERGO(size_t, MaxHeapSize, (size_t)reasonable_max);
+ 
+   } else {
+       set_use_compressed_oops(MaxHeapSize);
    }
  
    // If the minimum or initial heap_size have not been set or requested to be set
    // ergonomically, set them accordingly.
    if (InitialHeapSize == 0 || min_heap_size() == 0) {

*** 3857,3868 ****
--- 3847,3863 ----
    // Set flags based on ergonomics.
    jint result = set_ergonomics_flags();
    if (result != JNI_OK) return result;
  
    // Set heap size based on available physical memory
+   // Also calls set_use_compressed_oops().
    set_heap_size();
  
+   // set_use_compressed_klass_ptrs() must be called after calling
+   // set_use_compressed_oops().
+   set_use_compressed_klass_ptrs();
+ 
    GCConfig::arguments()->initialize();
  
    set_shared_spaces_flags();
  
    // Initialize Metaspace flags and alignments