8281811: assert(_base == Tuple) failed: Not a Tuple after JDK-8280799

Reviewed-by: kvn, thartmann

src/hotspot/share/opto/loopnode.cpp

@@ -4089,11 +4089,11 @@ bool PhaseIdealLoop::only_has_infinite_loops() {
 //----------------------------build_and_optimize-------------------------------
 // Create a PhaseLoop.  Build the ideal Loop tree.  Map each Ideal Node to
 // its corresponding LoopNode.  If 'optimize' is true, do some loop cleanups.
-void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
+void PhaseIdealLoop::build_and_optimize() {
   assert(!C->post_loop_opts_phase(), "no loop opts allowed");
 
-  bool do_split_ifs = (mode == LoopOptsDefault);
-  bool skip_loop_opts = (mode == LoopOptsNone);
+  bool do_split_ifs = (_mode == LoopOptsDefault);
+  bool skip_loop_opts = (_mode == LoopOptsNone);
 
   int old_progress = C->major_progress();
   uint orig_worklist_size = _igvn._worklist.size();
@@ -4164,9 +4164,9 @@ void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
   // Nothing to do, so get out
   bool stop_early = !C->has_loops() && !skip_loop_opts && !do_split_ifs && !_verify_me && !_verify_only &&
-    !bs->is_gc_specific_loop_opts_pass(mode);
+    !bs->is_gc_specific_loop_opts_pass(_mode);
   bool do_expensive_nodes = C->should_optimize_expensive_nodes(_igvn);
-  bool strip_mined_loops_expanded = bs->strip_mined_loops_expanded(mode);
+  bool strip_mined_loops_expanded = bs->strip_mined_loops_expanded(_mode);
   if (stop_early && !do_expensive_nodes) {
     return;
   }
@@ -4258,7 +4258,7 @@ void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
 
   if (_verify_only) {
     C->restore_major_progress(old_progress);
-    assert(C->unique() == unique, "verification mode made Nodes? ? ?");
+    assert(C->unique() == unique, "verification _mode made Nodes? ? ?");
     assert(_igvn._worklist.size() == orig_worklist_size, "shouldn't push anything");
     return;
   }
@@ -4288,8 +4288,8 @@ void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
 #ifndef PRODUCT
   C->verify_graph_edges();
   if (_verify_me) {             // Nested verify pass?
-    // Check to see if the verify mode is broken
-    assert(C->unique() == unique, "non-optimize mode made Nodes? ? ?");
+    // Check to see if the verify _mode is broken
+    assert(C->unique() == unique, "non-optimize _mode made Nodes? ? ?");
     return;
   }
   if (VerifyLoopOptimizations) verify();
@@ -4303,7 +4303,7 @@ void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
     return;
   }
 
-  if (mode == LoopOptsMaxUnroll) {
+  if (_mode == LoopOptsMaxUnroll) {
     for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) {
       IdealLoopTree* lpt = iter.current();
       if (lpt->is_innermost() && lpt->_allow_optimizations && !lpt->_has_call && lpt->is_counted()) {
@@ -4324,7 +4324,7 @@ void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
     return;
   }
 
-  if (bs->optimize_loops(this, mode, visited, nstack, worklist)) {
+  if (bs->optimize_loops(this, _mode, visited, nstack, worklist)) {
     return;
   }
 
@@ -5755,7 +5755,7 @@ void PhaseIdealLoop::build_loop_late_post_work(Node *n, bool pinned) {
   }
   // Try not to place code on a loop entry projection
   // which can inhibit range check elimination.
-  if (least != early) {
+  if (least != early && !BarrierSet::barrier_set()->barrier_set_c2()->is_gc_specific_loop_opts_pass(_mode)) {
     Node* ctrl_out = least->unique_ctrl_out_or_null();
     if (ctrl_out != NULL && ctrl_out->is_Loop() &&
         least == ctrl_out->in(LoopNode::EntryControl) &&

src/hotspot/share/opto/loopnode.hpp

@@ -1042,9 +1042,10 @@ private:
   Node **_idom;                  // Array of immediate dominators
   uint *_dom_depth;              // Used for fast LCA test
   GrowableArray<uint>* _dom_stk; // For recomputation of dom depth
+  LoopOptsMode _mode;
 
   // build the loop tree and perform any requested optimizations
-  void build_and_optimize(LoopOptsMode mode);
+  void build_and_optimize();
 
   // Dominators for the sea of nodes
   void Dominators();
@@ -1055,9 +1056,10 @@ private:
     _igvn(igvn),
     _verify_me(nullptr),
     _verify_only(false),
+    _mode(mode),
     _nodes_required(UINT_MAX) {
     assert(mode != LoopOptsVerify, "wrong constructor to verify IdealLoop");
-    build_and_optimize(mode);
+    build_and_optimize();
   }
 
 #ifndef PRODUCT
@@ -1068,8 +1070,9 @@ private:
     _igvn(igvn),
     _verify_me(verify_me),
     _verify_only(verify_me == nullptr),
+    _mode(LoopOptsVerify),
     _nodes_required(UINT_MAX) {
-    build_and_optimize(LoopOptsVerify);
+    build_and_optimize();
   }
 #endif
 

test/hotspot/jtreg/gc/shenandoah/compiler/TestBarrierAboveProj.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2022, Red Hat, Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * bug 8281811
+ * @summary assert(_base == Tuple) failed: Not a Tuple after JDK-8280799
+ * @requires vm.gc.Shenandoah
+ * @run main/othervm -XX:+UseShenandoahGC -XX:-BackgroundCompilation -XX:LoopMaxUnroll=1 TestBarrierAboveProj
+ */
+
+
+public class TestBarrierAboveProj {
+    private static C objField = new C();
+    private static final Object[] arrayField = new Object[1000];
+    private static volatile int volatileField;
+
+    public static void main(String[] args) {
+        for (int i = 0; i < 20_000; i++) {
+            test1();
+            test2();
+        }
+    }
+
+    private static float test1() {
+        float v = 1;
+        for (int i = 1; i < 1000; i++) {
+            if (objField == arrayField[i]) {
+                return v;
+            }
+            v *= 2;
+        }
+        return v;
+    }
+
+    private static float test2() {
+        float v = 1;
+        volatileField = 0x42;
+        for (int i = 1; i < 1000; i++) {
+            if (objField == arrayField[i]) {
+                return v;
+            }
+            v *= 2;
+        }
+        return v;
+    }
+
+    private static class C {
+        public float floatField;
+    }
+}