8248226: TestCloneAccessStressGCM fails with -XX:-ReduceBulkZeroing

Taking GC barriers into account in LoadNode::find_previous_arraycopy() when ReduceInitialCardMarks is disabled.

Reviewed-by: kvn, roland

Author: chhagedorn

src/hotspot/share/opto/memnode.cpp

@@ -532,11 +532,24 @@ bool MemNode::detect_ptr_independence(Node* p1, AllocateNode* a1,
 Node* LoadNode::find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const {
   if (mem->is_Proj() && mem->in(0) != NULL && (mem->in(0)->Opcode() == Op_MemBarStoreStore ||
                                                mem->in(0)->Opcode() == Op_MemBarCPUOrder)) {
-    Node* mb = mem->in(0);
-    if (mb->in(0) != NULL && mb->in(0)->is_Proj() &&
-        mb->in(0)->in(0) != NULL && mb->in(0)->in(0)->is_ArrayCopy()) {
-      ArrayCopyNode* ac = mb->in(0)->in(0)->as_ArrayCopy();
-      if (ac->is_clonebasic()) {
+    if (ld_alloc != NULL) {
+      // Check if there is an array copy for a clone
+      Node* mb = mem->in(0);
+      ArrayCopyNode* ac = NULL;
+      if (mb->in(0) != NULL && mb->in(0)->is_Proj() &&
+          mb->in(0)->in(0) != NULL && mb->in(0)->in(0)->is_ArrayCopy()) {
+        ac = mb->in(0)->in(0)->as_ArrayCopy();
+      } else {
+        // Step over GC barrier when ReduceInitialCardMarks is disabled
+        BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
+        Node* control_proj_ac = bs->step_over_gc_barrier(mb->in(0));
+
+        if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
+          ac = control_proj_ac->in(0)->as_ArrayCopy();
+        }
+      }
+
+      if (ac != NULL && ac->is_clonebasic()) {
         AllocateNode* alloc = AllocateNode::Ideal_allocation(ac->in(ArrayCopyNode::Dest), phase);
         if (alloc != NULL && alloc == ld_alloc) {
           return ac;

test/hotspot/jtreg/compiler/arraycopy/TestCloneAccessStressGCM.java

@@ -23,14 +23,19 @@
 
 /*
  * @test
- * @bug 8235332
+ * @bug 8235332 8248226
  * @summary Test cloning with more than 8 (=ArrayCopyLoadStoreMaxElem) fields with StressGCM
  * @library /
  *
  * @run main/othervm -Xbatch
  *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestCloneAccessStressGCM::test
  *                   -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:-ReduceInitialCardMarks
  *                   compiler.arraycopy.TestCloneAccessStressGCM
+ * @run main/othervm -Xbatch
+ *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestCloneAccessStressGCM::test
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:-ReduceInitialCardMarks
+ *                   -XX:-ReduceBulkZeroing
+ *                   compiler.arraycopy.TestCloneAccessStressGCM
  */
 
 package compiler.arraycopy;

test/hotspot/jtreg/compiler/arraycopy/TestEliminateArrayCopy.java

@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8076188 8246153
+ * @bug 8076188 8246153 8248226
  * @summary arraycopy to non escaping destination may be eliminated
  * @library /
  *
@@ -34,6 +34,11 @@
  *                   -XX:+IgnoreUnrecognizedVMOptions -XX:+StressReflectiveCode
  *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestEliminateArrayCopy*::m*
  *                   compiler.arraycopy.TestEliminateArrayCopy
+ * @run main/othervm -ea -XX:-BackgroundCompilation -XX:-UseOnStackReplacement
+ *                   -XX:+IgnoreUnrecognizedVMOptions -XX:+StressReflectiveCode
+ *                   -XX:-ReduceInitialCardMarks -XX:-ReduceBulkZeroing
+ *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestEliminateArrayCopy*::m*
+ *                   compiler.arraycopy.TestEliminateArrayCopy
  */
 
 package compiler.arraycopy;

test/hotspot/jtreg/compiler/arraycopy/TestInstanceCloneAsLoadsStores.java

@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 6700100 8156760
+ * @bug 6700100 8156760 8248226
  * @summary small instance clone as loads/stores
  * @library /
  *
@@ -38,6 +38,10 @@
  *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestInstanceCloneAsLoadsStores::m*
  *                   -XX:+IgnoreUnrecognizedVMOptions -XX:-ReduceInitialCardMarks
  *                   compiler.arraycopy.TestInstanceCloneAsLoadsStores
+ * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement
+ *                   -XX:CompileCommand=dontinline,compiler.arraycopy.TestInstanceCloneAsLoadsStores::m*
+ *                   -XX:+IgnoreUnrecognizedVMOptions -XX:-ReduceInitialCardMarks -XX:-ReduceBulkZeroing
+ *                   compiler.arraycopy.TestInstanceCloneAsLoadsStores
  */
 
 package compiler.arraycopy;