8365024: G1: Make G1CollectionSet::_inc_build_state assert-only

Reviewed-by: ayang, kbarrett

Author: Thomas Schatzl

src/hotspot/share/gc/g1/g1CollectionSet.cpp

@@ -67,7 +67,7 @@ G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) :
   _survivor_region_length(0),
   _initial_old_region_length(0),
   _optional_groups(),
-  _inc_build_state(CSetBuildType::Inactive),
+  DEBUG_ONLY(_inc_build_state(CSetBuildType::Inactive) COMMA)
   _regions_inc_part_start(0),
   _groups_inc_part_start(0) {
 }
@@ -142,11 +142,11 @@ void G1CollectionSet::continue_incremental_building() {
   _regions_inc_part_start = _regions_cur_length;
   _groups_inc_part_start = groups_cur_length();
 
-  _inc_build_state = CSetBuildType::Active;
+  DEBUG_ONLY(_inc_build_state = CSetBuildType::Active;)
 }
 
 void G1CollectionSet::stop_incremental_building() {
-  _inc_build_state = CSetBuildType::Inactive;
+  DEBUG_ONLY(_inc_build_state = CSetBuildType::Inactive;)
 }
 
 void G1CollectionSet::clear() {

src/hotspot/share/gc/g1/g1CollectionSet.hpp

@@ -165,12 +165,14 @@ class G1CollectionSet {
   // groups. Regions are reachable via this list as well.
   G1CSetCandidateGroupList _optional_groups;
 
+#ifdef ASSERT
   enum class CSetBuildType {
     Active,             // We are actively building the collection set
     Inactive            // We are not actively building the collection set
   };
 
   CSetBuildType _inc_build_state;
+#endif
   // Index into the _regions indicating the start of the current collection set increment.
   size_t _regions_inc_part_start;
   // Index into the _groups indicating the start of the current collection set increment.