From 81b3011925783d6eb1effec9b858e1d0e162d378 Mon Sep 17 00:00:00 2001
Date: Tue, 20 Aug 2019 21:09:30 +0000
Subject: [PATCH] Backport of JDK-8146792

summary: Predicate moved after partial peel may lead to broken
LLT:
Bug url: https://bugs.openjdk.java.net/browse/JDK-8146792
---
 hotspot/src/share/vm/opto/loopPredicate.cpp | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/hotspot/src/share/vm/opto/loopPredicate.cpp b/hotspot/src/share/vm/opto/loopPredicate.cpp
index db3447dc6e..f216fd9d1e 100644
--- a/hotspot/src/share/vm/opto/loopPredicate.cpp
+++ b/hotspot/src/share/vm/opto/loopPredicate.cpp
@@ -505,7 +505,31 @@ class Invariance : public StackObj {
     _lpt(lpt), _phase(lpt->_phase),
     _visited(area), _invariant(area), _stack(area, 10 /* guess */),
     _clone_visited(area), _old_new(area)
-  {}
+  {
+    Node* head = _lpt->_head;
+    Node* entry = head->in(LoopNode::EntryControl);
+    if (entry->outcnt() != 1) {
+      // If a node is pinned between the predicates and the loop
+      // entry, we won't be able to move any node in the loop that
+      // depends on it above it in a predicate. Mark all those nodes
+      // as non loop invariatnt.
+      Unique_Node_List wq;
+      wq.push(entry);
+      for (uint next = 0; next < wq.size(); ++next) {
+        Node *n = wq.at(next);
+        for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
+          Node* u = n->fast_out(i);
+          if (!u->is_CFG()) {
+            Node* c = _phase->get_ctrl(u);
+            if (_lpt->is_member(_phase->get_loop(c)) || _phase->is_dominator(c, head)) {
+              _visited.set(u->_idx);
+              wq.push(u);
+            }
+          }
+        }
+      }
+    }
+  }
 
   // Map old to n for invariance computation and clone
   void map_ctrl(Node* old, Node* n) {
-- 
2.12.3