# HG changeset patch
# User roland
# Date 1487208397 28800
# Node ID 35db0413819a18edd6718dd42e7536182c42aa8b
# Parent  ac559f3ccca81de373f18ac7c4b2d813d0278920
8174164: SafePointNode::_replaced_nodes breaks with irreducible loops
Reviewed-by: kvn

diff -r ac559f3ccca8 -r 35db0413819a src/share/vm/opto/callnode.hpp
--- openjdk/hotspot/src/share/vm/opto/callnode.hpp	Wed Feb 15 11:14:45 2017 +0100
+++ openjdk/hotspot/src/share/vm/opto/callnode.hpp	Wed Feb 15 17:26:37 2017 -0800
@@ -452,8 +452,8 @@
   void delete_replaced_nodes() {
     _replaced_nodes.reset();
   }
-  void apply_replaced_nodes() {
-    _replaced_nodes.apply(this);
+  void apply_replaced_nodes(uint idx) {
+    _replaced_nodes.apply(this, idx);
   }
   void merge_replaced_nodes_with(SafePointNode* sfpt) {
     _replaced_nodes.merge_with(sfpt->_replaced_nodes);
# I was informed that this hunk is not necessary in jdk8
#diff -r ac559f3ccca8 -r 35db0413819a src/share/vm/opto/library_call.cpp
#--- openjdk/hotspot/src/share/vm/opto/library_call.cpp	Wed Feb 15 11:14:45 2017 +0100
#+++ openjdk/hotspot/src/share/vm/opto/library_call.cpp	Wed Feb 15 17:26:37 2017 -0800
#@@ -277,7 +277,8 @@
#   AllocateArrayNode* tightly_coupled_allocation(Node* ptr,
#                                                 RegionNode* slow_region);
#   JVMState* arraycopy_restore_alloc_state(AllocateArrayNode* alloc, int& saved_reexecute_sp);
#-  void arraycopy_move_allocation_here(AllocateArrayNode* alloc, Node* dest, JVMState* saved_jvms, int saved_reexecute_sp);
#+  void arraycopy_move_allocation_here(AllocateArrayNode* alloc, Node* dest, JVMState* saved_jvms, int saved_reexecute_sp,
#+                                      uint new_idx);
# 
#   typedef enum { LS_get_add, LS_get_set, LS_cmp_swap, LS_cmp_swap_weak, LS_cmp_exchange } LoadStoreKind;
#   MemNode::MemOrd access_kind_to_memord_LS(AccessKind access_kind, bool is_store);
#@@ -4882,7 +4883,8 @@
# // deoptimize. This is possible because tightly_coupled_allocation()
# // guarantees there's no observer of the allocated array at this point
# // and the control flow is simple enough.
#-void LibraryCallKit::arraycopy_move_allocation_here(AllocateArrayNode* alloc, Node* dest, JVMState* saved_jvms, int saved_reexecute_sp) {
#+void LibraryCallKit::arraycopy_move_allocation_here(AllocateArrayNode* alloc, Node* dest, JVMState* saved_jvms,
#+                                                    int saved_reexecute_sp, uint new_idx) {
#   if (saved_jvms != NULL && !stopped()) {
#     assert(alloc != NULL, "only with a tightly coupled allocation");
#     // restore JVM state to the state at the arraycopy
#@@ -4891,7 +4893,7 @@
#     assert(saved_jvms->map()->i_o() == map()->i_o(), "IO state changed?");
#     // If we've improved the types of some nodes (null check) while
#     // emitting the guards, propagate them to the current state
#-    map()->replaced_nodes().apply(saved_jvms->map());
#+    map()->replaced_nodes().apply(saved_jvms->map(), new_idx);
#     set_jvms(saved_jvms);
#     _reexecute_sp = saved_reexecute_sp;
# 
#@@ -4949,6 +4951,7 @@
#   Node* dest_offset = argument(3);  // type: int
#   Node* length      = argument(4);  // type: int
# 
#+  uint new_idx = C->unique();
# 
#   // Check for allocation before we add nodes that would confuse
#   // tightly_coupled_allocation()
#@@ -5164,7 +5167,7 @@
#     }
#   }
# 
#-  arraycopy_move_allocation_here(alloc, dest, saved_jvms, saved_reexecute_sp);
#+  arraycopy_move_allocation_here(alloc, dest, saved_jvms, saved_reexecute_sp, new_idx);
# 
#   if (stopped()) {
#     return true;
diff -r ac559f3ccca8 -r 35db0413819a src/share/vm/opto/parse1.cpp
--- openjdk/hotspot/src/share/vm/opto/parse1.cpp	Wed Feb 15 11:14:45 2017 +0100
+++ openjdk/hotspot/src/share/vm/opto/parse1.cpp	Wed Feb 15 17:26:37 2017 -0800
@@ -1086,7 +1086,7 @@
         kit.make_dtrace_method_exit(method());
       }
       if (_replaced_nodes_for_exceptions) {
-        kit.map()->apply_replaced_nodes();
+        kit.map()->apply_replaced_nodes(_new_idx);
       }
       // Done with exception-path processing.
       ex_map = kit.make_exception_state(ex_oop);
@@ -1107,7 +1107,7 @@
       _exits.add_exception_state(ex_map);
     }
   }
-  _exits.map()->apply_replaced_nodes();
+  _exits.map()->apply_replaced_nodes(_new_idx);
 }
 
 //-----------------------------create_entry_map-------------------------------
diff -r ac559f3ccca8 -r 35db0413819a src/share/vm/opto/replacednodes.cpp
--- openjdk/hotspot/src/share/vm/opto/replacednodes.cpp	Wed Feb 15 11:14:45 2017 +0100
+++ openjdk/hotspot/src/share/vm/opto/replacednodes.cpp	Wed Feb 15 17:26:37 2017 -0800
@@ -92,13 +92,17 @@
 }
 
 // Perfom node replacement (used when returning to caller)
-void ReplacedNodes::apply(Node* n) {
+void ReplacedNodes::apply(Node* n, uint idx) {
   if (is_empty()) {
     return;
   }
   for (int i = 0; i < _replaced_nodes->length(); i++) {
     ReplacedNode replaced = _replaced_nodes->at(i);
-    n->replace_edge(replaced.initial(), replaced.improved());
+    // Only apply if improved node was created in a callee to avoid
+    // issues with irreducible loops in the caller
+    if (replaced.improved()->_idx >= idx) {
+      n->replace_edge(replaced.initial(), replaced.improved());
+    }
   }
 }
 
diff -r ac559f3ccca8 -r 35db0413819a src/share/vm/opto/replacednodes.hpp
--- openjdk/hotspot/src/share/vm/opto/replacednodes.hpp	Wed Feb 15 11:14:45 2017 +0100
+++ openjdk/hotspot/src/share/vm/opto/replacednodes.hpp	Wed Feb 15 17:26:37 2017 -0800
@@ -71,7 +71,7 @@
   void record(Node* initial, Node* improved);
   void transfer_from(const ReplacedNodes& other, uint idx);
   void reset();
-  void apply(Node* n);
+  void apply(Node* n, uint idx);
   void merge_with(const ReplacedNodes& other);
   bool is_empty() const;
   void dump(outputStream *st) const;