# HG changeset patch
# Parent  4ffc7f608c8cd5779c56f36ac0b8600978e0610b

diff -r 4ffc7f608c8c -r b7ae94e0a9fd src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Mon Mar 02 21:19:11 2020 +0100
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Mon Mar 02 21:53:43 2020 +0100
@@ -901,7 +901,7 @@
   phase->register_new_node(heap_stable_cmp, ctrl);
   Node* heap_stable_test = new BoolNode(heap_stable_cmp, BoolTest::ne);
   phase->register_new_node(heap_stable_test, ctrl);
-  IfNode* heap_stable_iff = new IfNode(ctrl, heap_stable_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
+  IfNode* heap_stable_iff = new IfNode(ctrl, heap_stable_test, PROB_FAIR, COUNT_UNKNOWN);
   phase->register_control(heap_stable_iff, loop, ctrl);
 
   heap_stable_ctrl = new IfFalseNode(heap_stable_iff);
@@ -1462,6 +1462,27 @@
     Node* gc_state = new LoadBNode(ctrl, raw_mem, gc_state_addr, gc_state_adr_type, TypeInt::BYTE, MemNode::unordered);
     phase->register_new_node(gc_state, ctrl);
 
+    enum { _gc_inactive = 1, _gc_active, PATH_LIMIT_OUTER };
+    Node* region_outer = new RegionNode(PATH_LIMIT_OUTER);
+    Node* val_phi_outer = new PhiNode(region_outer, uncasted_val->bottom_type()->is_oopptr());
+    Node* phi_outer = PhiNode::make(region_outer, raw_mem, Type::MEMORY, TypeRawPtr::BOTTOM);
+
+    Node* gc_active_cmp = new CmpINode(gc_state, phase->igvn().zerocon(T_INT));
+    phase->register_new_node(gc_active_cmp, ctrl);
+    Node* gc_active_test = new BoolNode(gc_active_cmp, BoolTest::ne);
+    phase->register_new_node(gc_active_test, ctrl);
+    IfNode* gc_active_iff = new IfNode(ctrl, gc_active_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
+    phase->register_control(gc_active_iff, loop, ctrl);
+
+    Node* gc_inactive_ctrl = new IfFalseNode(gc_active_iff);
+    phase->register_control(gc_inactive_ctrl, loop, gc_active_iff);
+    ctrl = new IfTrueNode(gc_active_iff);
+    phase->register_control(ctrl, loop, gc_active_iff);
+
+    region_outer->init_req(_gc_inactive, gc_inactive_ctrl);
+    val_phi_outer->init_req(_gc_inactive, uncasted_val);
+    phi_outer->init_req(_gc_inactive, raw_mem);
+
     if (lrb->need_concmark_barrier()) {
       Node* heap_stable_ctrl = NULL;
       Node* null_ctrl = NULL;
@@ -1668,11 +1689,15 @@
     raw_mem_phi->init_req(_evac_path, result_mem);
 
     phase->register_control(region, loop, heap_stable_iff);
-    Node* out_val = val_phi;
     phase->register_new_node(val_phi, region);
     phase->register_new_node(raw_mem_phi, region);
 
-    fix_ctrl(lrb, region, fixer, uses, uses_to_ignore, last, phase);
+    region_outer->init_req(_gc_active, region);
+    val_phi_outer->init_req(_gc_active, val_phi);
+    phi_outer->init_req(_gc_active, raw_mem_phi);
+    Node* out_val = val_phi_outer;
+
+    fix_ctrl(lrb, region_outer, fixer, uses, uses_to_ignore, last, phase);
 
     ctrl = orig_ctrl;
 
@@ -1698,7 +1723,7 @@
       Node *n = uses.at(next);
       assert(phase->get_ctrl(n) == ctrl, "bad control");
       assert(n != init_raw_mem, "should leave input raw mem above the barrier");
-      phase->set_ctrl(n, region);
+      phase->set_ctrl(n, region_outer);
       follow_barrier_uses(n, ctrl, uses, phase);
     }
 
@@ -1708,7 +1733,7 @@
     // region and at enclosing loop heads. Use the memory state
     // collected in memory_nodes to fix the memory graph. Update that
     // memory state as we go.
-    fixer.fix_mem(ctrl, region, init_raw_mem, raw_mem_for_ctrl, raw_mem_phi, uses);
+    fixer.fix_mem(ctrl, region_outer, init_raw_mem, raw_mem_for_ctrl, phi_outer, uses);
   }
   // Done expanding load-reference-barriers.
   assert(ShenandoahBarrierSetC2::bsc2()->state()->load_reference_barriers_count() == 0, "all load reference barrier nodes should have been replaced");