# HG changeset patch
# User aph
# Date 1466704739 0
#      Thu Jun 23 17:58:59 2016 +0000
# Node ID 89b3911c92aef18f2fd24ab4a31fbb47954462fa
# Parent  9febe12cbce4c6aa428a78f6a78906909e2954a4
8157306: Random infrequent null pointer exceptions in javac
Reviewed-by: kvn

diff --git openjdk/hotspot/src/share/vm/opto/block.cpp b/src/share/vm/opto/block.cpp
--- openjdk/hotspot/src/share/vm/opto/block.cpp
+++ openjdk/hotspot/src/share/vm/opto/block.cpp
@@ -1212,6 +1212,9 @@
       if (j >= 1 && n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_CreateEx) {
         assert(j == 1 || block->get_node(j-1)->is_Phi(), "CreateEx must be first instruction in block");
       }
+      if (n->needs_anti_dependence_check()) {
+        verify_anti_dependences(block, n);
+      }
       for (uint k = 0; k < n->req(); k++) {
         Node *def = n->in(k);
         if (def && def != n) {
diff --git a/src/share/vm/opto/block.hpp b/src/share/vm/opto/block.hpp
--- openjdk/hotspot/src/share/vm/opto/block.hpp
+++ openjdk/hotspot/src/share/vm/opto/block.hpp
@@ -481,9 +481,9 @@
   MachNode* _goto;
 
   Block* insert_anti_dependences(Block* LCA, Node* load, bool verify = false);
-  void verify_anti_dependences(Block* LCA, Node* load) {
+  void verify_anti_dependences(Block* LCA, Node* load) const {
     assert(LCA == get_block_for_node(load), "should already be scheduled");
-    insert_anti_dependences(LCA, load, true);
+    const_cast<PhaseCFG*>(this)->insert_anti_dependences(LCA, load, true);
   }
 
   bool move_to_next(Block* bx, uint b_index);
diff --git a/src/share/vm/opto/lcm.cpp b/src/share/vm/opto/lcm.cpp
--- openjdk/hotspot/src/share/vm/opto/lcm.cpp
+++ openjdk/hotspot/src/share/vm/opto/lcm.cpp
@@ -1293,11 +1293,12 @@
     Block *sb = block->_succs[i];
     // Clone the entire area; ignoring the edge fixup for now.
     for( uint j = end; j > beg; j-- ) {
-      // It is safe here to clone a node with anti_dependence
-      // since clones dominate on each path.
       Node *clone = block->get_node(j-1)->clone();
       sb->insert_node(clone, 1);
       map_node_to_block(clone, sb);
+      if (clone->needs_anti_dependence_check()) {
+        insert_anti_dependences(sb, clone);
+      }
     }
   }