# HG changeset patch
# Parent 8d0505df77a82e1e8cde2a10cb445bf4819f36b3
diff --git a/src/hotspot/share/opto/compile.cpp b/src/hotspot/share/opto/compile.cpp
--- a/src/hotspot/share/opto/compile.cpp
+++ b/src/hotspot/share/opto/compile.cpp
@@ -3381,7 +3381,7 @@
   }
   case Op_If: {
 #ifdef ASSERT
-    if (ShenandoahWriteBarrierNode::is_evacuation_in_progress_test(n->as_If())) {
+    if (ShenandoahWBWithMemBar && ShenandoahWriteBarrierNode::is_evacuation_in_progress_test(n->as_If())) {
       Node* c = n->in(0);
       int count = 0;
       for (;;) {
diff --git a/src/hotspot/share/opto/shenandoahSupport.cpp b/src/hotspot/share/opto/shenandoahSupport.cpp
--- a/src/hotspot/share/opto/shenandoahSupport.cpp
+++ b/src/hotspot/share/opto/shenandoahSupport.cpp
@@ -595,10 +595,12 @@
 Node* ShenandoahWriteBarrierNode::evacuation_in_progress_test_ctrl(Node* iff) {
   assert(is_evacuation_in_progress_test(iff), "bad input");
   Node* c = iff;
-  do {
-    assert(c->in(0)->is_Proj() && c->in(0)->in(0)->is_MemBar(), "where's the mem bar?");
-    c = c->in(0)->in(0);
-  } while (c->adr_type() != TypeRawPtr::BOTTOM);
+  if (ShenandoahWBWithMemBar) {
+    do {
+      assert(c->in(0)->is_Proj() && c->in(0)->in(0)->is_MemBar(), "where's the mem bar?");
+      c = c->in(0)->in(0);
+    } while (c->adr_type() != TypeRawPtr::BOTTOM);
+  }
   return c->in(0);
 }
 
@@ -3480,30 +3482,33 @@
                                                 evacuation_in_progress_adr_type, TypeInt::BOOL, MemNode::unordered);
   phase->register_new_node(evacuation_in_progress, ctrl);
 
-  Node* mb = MemBarNode::make(phase->C, Op_MemBarAcquire, Compile::AliasIdxRaw);
-  mb->init_req(TypeFunc::Control, ctrl);
-  mb->init_req(TypeFunc::Memory, raw_mem);
-  phase->register_control(mb, loop, ctrl);
-  Node* ctrl_proj = new ProjNode(mb,TypeFunc::Control);
-  phase->register_control(ctrl_proj, loop, mb);
-  raw_mem = new ProjNode(mb, TypeFunc::Memory);
-  phase->register_new_node(raw_mem, mb);
-
-  mb = MemBarNode::make(phase->C, Op_MemBarAcquire, alias);
-  mb->init_req(TypeFunc::Control, ctrl_proj);
-  mb->init_req(TypeFunc::Memory, wb_mem);
-  phase->register_control(mb, loop, ctrl_proj);
-  ctrl_proj = new ProjNode(mb,TypeFunc::Control);
-  phase->register_control(ctrl_proj, loop, mb);
-  wb_mem = new ProjNode(mb,TypeFunc::Memory);
-  phase->register_new_node(wb_mem, mb);
+  if (ShenandoahWBWithMemBar) {
+    Node* mb = MemBarNode::make(phase->C, Op_MemBarAcquire, Compile::AliasIdxRaw);
+    mb->init_req(TypeFunc::Control, ctrl);
+    mb->init_req(TypeFunc::Memory, raw_mem);
+    phase->register_control(mb, loop, ctrl);
+    Node* ctrl_proj = new ProjNode(mb,TypeFunc::Control);
+    phase->register_control(ctrl_proj, loop, mb);
+    raw_mem = new ProjNode(mb, TypeFunc::Memory);
+    phase->register_new_node(raw_mem, mb);
+
+    mb = MemBarNode::make(phase->C, Op_MemBarAcquire, alias);
+    mb->init_req(TypeFunc::Control, ctrl_proj);
+    mb->init_req(TypeFunc::Memory, wb_mem);
+    phase->register_control(mb, loop, ctrl_proj);
+    ctrl_proj = new ProjNode(mb,TypeFunc::Control);
+    phase->register_control(ctrl_proj, loop, mb);
+    wb_mem = new ProjNode(mb,TypeFunc::Memory);
+    phase->register_new_node(wb_mem, mb);
+    ctrl = ctrl_proj;
+  }
 
   Node* evacuation_in_progress_cmp = new CmpINode(evacuation_in_progress, phase->igvn().zerocon(T_INT));
-  phase->register_new_node(evacuation_in_progress_cmp, ctrl_proj);
+  phase->register_new_node(evacuation_in_progress_cmp, ctrl);
   Node* evacuation_in_progress_test = new BoolNode(evacuation_in_progress_cmp, BoolTest::ne);
-  phase->register_new_node(evacuation_in_progress_test, ctrl_proj);
-  evacuation_iff = new IfNode(ctrl_proj, evacuation_in_progress_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
-  phase->register_control(evacuation_iff, loop, ctrl_proj);
+  phase->register_new_node(evacuation_in_progress_test, ctrl);
+  evacuation_iff = new IfNode(ctrl, evacuation_in_progress_test, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
+  phase->register_control(evacuation_iff, loop, ctrl);
 
   assert(is_evacuation_in_progress_test(evacuation_iff), "inconsistent");
 
@@ -3909,6 +3914,7 @@
 }
 
 void ShenandoahWriteBarrierNode::move_evacuation_test_out_of_loop(IfNode* iff, PhaseIdealLoop* phase) {
+  if (!ShenandoahWBWithMemBar) return;
   // move test and its mem barriers out of the loop
   assert(is_evacuation_in_progress_test(iff), "inconsistent");
 
@@ -3941,7 +3947,6 @@
     assert(new_proj_mem->outcnt() >= 1, "memory projection is disconnected");
     new_mbs.push(new_proj_ctrl);
   } while (mb->adr_type() != TypeRawPtr::BOTTOM);
-
   c = entry_c;
   for (int i = new_mbs.length()-1; i >= 0; i--) {
     Node* proj_ctrl = new_mbs.at(i);
@@ -3989,6 +3994,7 @@
 }
 
 void ShenandoahWriteBarrierNode::backtoback_evacs(IfNode* iff, IfNode* dom_if, PhaseIdealLoop* phase) {
+  if (!ShenandoahWBWithMemBar) return;
   // move all mem barriers from this evac test to the dominating one,
   // removing duplicates in the process
   IdealLoopTree *loop = phase->get_loop(dom_if);