From c2d7c271a60a6892bbbf7a2d585aa5b50c85bef1 Mon Sep 17 00:00:00 2001
Date: Sat, 23 May 2020 17:40:00 +0800
Subject: [PATCH] 8080289 8040213 8189067: move the store out of the loop

Summary: <superWord>  : move the store out of the loop
LLT: NA
Bug url: https://bugs.openjdk.java.net/browse/JDK-8080289 https://bugs.openjdk.java.net/browse/JDK-8040213 https://bugs.openjdk.java.net/browse/JDK-8189067
---
 hotspot/src/share/vm/opto/loopnode.cpp        |   2 +-
 hotspot/src/share/vm/opto/loopnode.hpp        |   4 +-
 hotspot/src/share/vm/opto/loopopts.cpp        | 191 +++++++++++
 hotspot/src/share/vm/opto/memnode.cpp         |  58 ++--
 hotspot/src/share/vm/opto/phaseX.hpp          |   9 +-
 .../loopopts/TestMoveStoresOutOfLoops.java    | 310 ++++++++++++++++++
 6 files changed, 545 insertions(+), 29 deletions(-)
 create mode 100644 hotspot/test/compiler/loopopts/TestMoveStoresOutOfLoops.java

diff --git a/hotspot/src/share/vm/opto/loopnode.cpp b/hotspot/src/share/vm/opto/loopnode.cpp
index 0a44d7ede..7ab9bf893 100644
--- a/hotspot/src/share/vm/opto/loopnode.cpp
+++ b/hotspot/src/share/vm/opto/loopnode.cpp
@@ -1192,7 +1192,7 @@ void CountedLoopEndNode::dump_spec(outputStream *st) const {
 //=============================================================================
 //------------------------------is_member--------------------------------------
 // Is 'l' a member of 'this'?
-int IdealLoopTree::is_member( const IdealLoopTree *l ) const {
+bool IdealLoopTree::is_member(const IdealLoopTree *l) const {
   while( l->_nest > _nest ) l = l->_parent;
   return l == this;
 }
diff --git a/hotspot/src/share/vm/opto/loopnode.hpp b/hotspot/src/share/vm/opto/loopnode.hpp
index 558b10504..21995dda6 100644
--- a/hotspot/src/share/vm/opto/loopnode.hpp
+++ b/hotspot/src/share/vm/opto/loopnode.hpp
@@ -371,7 +371,7 @@ public:
   { }
 
   // Is 'l' a member of 'this'?
-  int is_member( const IdealLoopTree *l ) const; // Test for nested membership
+  bool is_member(const IdealLoopTree *l) const; // Test for nested membership
 
   // Set loop nesting depth.  Accumulate has_call bits.
   int set_nest( uint depth );
@@ -1075,6 +1075,8 @@ private:
   bool split_up( Node *n, Node *blk1, Node *blk2 );
   void sink_use( Node *use, Node *post_loop );
   Node *place_near_use( Node *useblock ) const;
+  Node* try_move_store_before_loop(Node* n, Node *n_ctrl);
+  void try_move_store_after_loop(Node* n);
 
   bool _created_loop_node;
 public:
diff --git a/hotspot/src/share/vm/opto/loopopts.cpp b/hotspot/src/share/vm/opto/loopopts.cpp
index 62273d86d..ec244e363 100644
--- a/hotspot/src/share/vm/opto/loopopts.cpp
+++ b/hotspot/src/share/vm/opto/loopopts.cpp
@@ -673,6 +673,190 @@ Node *PhaseIdealLoop::conditional_move( Node *region ) {
   return iff->in(1);
 }
 
+#ifdef ASSERT
+static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
+  for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
+    Node* u = m->fast_out(i);
+    if (u->is_CFG()) {
+      if (u->Opcode() == Op_NeverBranch) {
+        u = ((NeverBranchNode*)u)->proj_out(0);
+        enqueue_cfg_uses(u, wq);
+      } else {
+        wq.push(u);
+      }
+    }
+  }
+}
+#endif
+
+// Try moving a store out of a loop, right before the loop
+Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
+  // Store has to be first in the loop body
+  IdealLoopTree *n_loop = get_loop(n_ctrl);
+  if (n->is_Store() && n_loop != _ltree_root && n_loop->is_loop()) {
+    assert(n->in(0), "store should have control set");
+    Node* address = n->in(MemNode::Address);
+    Node* value = n->in(MemNode::ValueIn);
+    Node* mem = n->in(MemNode::Memory);
+    IdealLoopTree* address_loop = get_loop(get_ctrl(address));
+    IdealLoopTree* value_loop = get_loop(get_ctrl(value));
+
+    // - address and value must be loop invariant
+    // - memory must be a memory Phi for the loop
+    // - Store must be the only store on this memory slice in the
+    // loop: if there's another store following this one then value
+    // written at iteration i by the second store could be overwritten
+    // at iteration i+n by the first store: it's not safe to move the
+    // first store out of the loop
+    // - nothing must observe the Phi memory: it guarantees no read
+    // before the store and no early exit out of the loop
+    // With those conditions, we are also guaranteed the store post
+    // dominates the loop head. Otherwise there would be extra Phi
+    // involved between the loop's Phi and the store.
+
+    if (!n_loop->is_member(address_loop) &&
+        !n_loop->is_member(value_loop) &&
+        mem->is_Phi() && mem->in(0) == n_loop->_head &&
+        mem->outcnt() == 1 &&
+        mem->in(LoopNode::LoopBackControl) == n) {
+
+#ifdef ASSERT
+      // Verify that store's control does post dominate loop entry and
+      // that there's no early exit of the loop before the store.
+      bool ctrl_ok = false;
+      {
+        // Follow control from loop head until n, we exit the loop or
+        // we reach the tail
+        ResourceMark rm;
+        Unique_Node_List wq;
+        wq.push(n_loop->_head);
+        assert(n_loop->_tail != NULL, "need a tail");
+        for (uint next = 0; next < wq.size(); ++next) {
+          Node *m = wq.at(next);
+          if (m == n->in(0)) {
+            ctrl_ok = true;
+            continue;
+          }
+          assert(!has_ctrl(m), "should be CFG");
+          if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
+            ctrl_ok = false;
+            break;
+          }
+          enqueue_cfg_uses(m, wq);
+        }
+      }
+      assert(ctrl_ok, "bad control");
+#endif
+
+      // move the Store
+      _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
+      _igvn.replace_input_of(n, 0, n_loop->_head->in(LoopNode::EntryControl));
+      _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
+      // Disconnect the phi now. An empty phi can confuse other
+      // optimizations in this pass of loop opts.
+      _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
+      n_loop->_body.yank(mem);
+
+      IdealLoopTree* new_loop = get_loop(n->in(0));
+      set_ctrl_and_loop(n, n->in(0));
+
+      return n;
+    }
+  }
+  return NULL;
+}
+
+// Try moving a store out of a loop, right after the loop
+void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
+  if (n->is_Store()) {
+    assert(n->in(0), "store should have control set");
+    Node *n_ctrl = get_ctrl(n);
+    IdealLoopTree *n_loop = get_loop(n_ctrl);
+    // Store must be in a loop
+    if (n_loop != _ltree_root && !n_loop->_irreducible) {
+      Node* address = n->in(MemNode::Address);
+      Node* value = n->in(MemNode::ValueIn);
+      IdealLoopTree* address_loop = get_loop(get_ctrl(address));
+      // address must be loop invariant
+      if (!n_loop->is_member(address_loop)) {
+        // Store must be last on this memory slice in the loop and
+        // nothing in the loop must observe it
+        Node* phi = NULL;
+        for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
+          Node* u = n->fast_out(i);
+          if (has_ctrl(u)) { // control use?
+            IdealLoopTree *u_loop = get_loop(get_ctrl(u));
+            if (!n_loop->is_member(u_loop)) {
+              continue;
+            }
+            if (u->is_Phi() && u->in(0) == n_loop->_head) {
+              assert(_igvn.type(u) == Type::MEMORY, "bad phi");
+              assert(phi == NULL, "already found");
+              phi = u;
+              continue;
+            }
+          }
+          phi = NULL;
+          break;
+        }
+        if (phi != NULL) {
+          // Nothing in the loop before the store (next iteration)
+          // must observe the stored value
+          bool mem_ok = true;
+          {
+            ResourceMark rm;
+            Unique_Node_List wq;
+            wq.push(phi);
+            for (uint next = 0; next < wq.size() && mem_ok; ++next) {
+              Node *m = wq.at(next);
+              for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
+                Node* u = m->fast_out(i);
+                if (u->is_Store() || u->is_Phi()) {
+                  if (u != n) {
+                    wq.push(u);
+                    mem_ok = (wq.size() <= 10);
+                  }
+                } else {
+                  mem_ok = false;
+                  break;
+                }
+              }
+            }
+          }
+          if (mem_ok) {
+              // Move the store out of the loop if the LCA of all
+              // users (except for the phi) is outside the loop.
+              Node* hook = new (C) Node(1);
+              _igvn.rehash_node_delayed(phi);
+              int count = phi->replace_edge(n, hook);
+              assert(count > 0, "inconsistent phi");
+
+              // Compute latest point this store can go
+              Node* lca = get_late_ctrl(n, get_ctrl(n));
+              if (n_loop->is_member(get_loop(lca))) {
+                  // LCA is in the loop - bail out
+                  _igvn.replace_node(hook, n);
+                  return;
+              }
+
+              // Move store out of the loop
+              _igvn.replace_node(hook, n->in(MemNode::Memory));
+              _igvn.replace_input_of(n, 0, lca);
+              set_ctrl_and_loop(n, lca);
+
+            // Disconnect the phi now. An empty phi can confuse other
+            // optimizations in this pass of loop opts..
+            if (phi->in(LoopNode::LoopBackControl) == phi) {
+              _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
+              n_loop->_body.yank(phi);
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
 //------------------------------split_if_with_blocks_pre-----------------------
 // Do the real work in a non-recursive function.  Data nodes want to be
 // cloned in the pre-order so they can feed each other nicely.
@@ -703,6 +887,11 @@ Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
   Node *n_ctrl = get_ctrl(n);
   if( !n_ctrl ) return n;       // Dead node
 
+  Node* res = try_move_store_before_loop(n, n_ctrl);
+  if (res != NULL) {
+    return n;
+  }
+
   // Attempt to remix address expressions for loop invariants
   Node *m = remix_address_expressions( n );
   if( m ) return m;
@@ -1057,6 +1246,8 @@ void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) {
     }
   }
 
+  try_move_store_after_loop(n);
+
   // Check for Opaque2's who's loop has disappeared - who's input is in the
   // same loop nest as their output.  Remove 'em, they are no longer useful.
   if( n_op == Op_Opaque2 &&
diff --git a/hotspot/src/share/vm/opto/memnode.cpp b/hotspot/src/share/vm/opto/memnode.cpp
index 3ecbe1ce0..1bab75927 100644
--- a/hotspot/src/share/vm/opto/memnode.cpp
+++ b/hotspot/src/share/vm/opto/memnode.cpp
@@ -2313,33 +2313,39 @@ Node *StoreNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // unsafe if I have intervening uses...  Also disallowed for StoreCM
   // since they must follow each StoreP operation.  Redundant StoreCMs
   // are eliminated just before matching in final_graph_reshape.
-  if (mem->is_Store() && mem->in(MemNode::Address)->eqv_uncast(address) &&
-      mem->Opcode() != Op_StoreCM) {
-    // Looking at a dead closed cycle of memory?
-    assert(mem != mem->in(MemNode::Memory), "dead loop in StoreNode::Ideal");
-
-    assert(Opcode() == mem->Opcode() ||
-           phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw ||
-           (is_mismatched_access() || mem->as_Store()->is_mismatched_access()),
-           "no mismatched stores, except on raw memory");
-
-    if (mem->outcnt() == 1 &&           // check for intervening uses
-        mem->as_Store()->memory_size() <= this->memory_size()) {
-      // If anybody other than 'this' uses 'mem', we cannot fold 'mem' away.
-      // For example, 'mem' might be the final state at a conditional return.
-      // Or, 'mem' might be used by some node which is live at the same time
-      // 'this' is live, which might be unschedulable.  So, require exactly
-      // ONE user, the 'this' store, until such time as we clone 'mem' for
-      // each of 'mem's uses (thus making the exactly-1-user-rule hold true).
-      if (can_reshape) {  // (%%% is this an anachronism?)
-        set_req_X(MemNode::Memory, mem->in(MemNode::Memory),
-                  phase->is_IterGVN());
-      } else {
-        // It's OK to do this in the parser, since DU info is always accurate,
-        // and the parser always refers to nodes via SafePointNode maps.
-        set_req(MemNode::Memory, mem->in(MemNode::Memory));
+  {
+    Node* st = mem;
+    // If Store 'st' has more than one use, we cannot fold 'st' away.
+    // For example, 'st' might be the final state at a conditional
+    // return.  Or, 'st' might be used by some node which is live at
+    // the same time 'st' is live, which might be unschedulable.  So,
+    // require exactly ONE user until such time as we clone 'mem' for
+    // each of 'mem's uses (thus making the exactly-1-user-rule hold
+    // true).
+    while (st->is_Store() && st->outcnt() == 1 && st->Opcode() != Op_StoreCM) {
+      // Looking at a dead closed cycle of memory?
+      assert(st != st->in(MemNode::Memory), "dead loop in StoreNode::Ideal");
+      assert(Opcode() == st->Opcode() ||
+             st->Opcode() == Op_StoreVector ||
+             Opcode() == Op_StoreVector ||
+             phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw ||
+             (Opcode() == Op_StoreL && st->Opcode() == Op_StoreI), // expanded ClearArrayNode
+             err_msg_res("no mismatched stores, except on raw memory: %s %s", NodeClassNames[Opcode()], NodeClassNames[st->Opcode()]));
+
+      if (st->in(MemNode::Address)->eqv_uncast(address) &&
+          st->as_Store()->memory_size() <= this->memory_size()) {
+        Node* use = st->raw_out(0);
+        phase->igvn_rehash_node_delayed(use);
+        if (can_reshape) {
+          use->set_req_X(MemNode::Memory, st->in(MemNode::Memory), phase->is_IterGVN());
+        } else {
+          // It's OK to do this in the parser, since DU info is always accurate,
+          // and the parser always refers to nodes via SafePointNode maps.
+          use->set_req(MemNode::Memory, st->in(MemNode::Memory));
+        }
+        return this;
       }
-      return this;
+      st = st->in(MemNode::Memory);
     }
   }
 
diff --git a/hotspot/src/share/vm/opto/phaseX.hpp b/hotspot/src/share/vm/opto/phaseX.hpp
index 332b1175d..852a1c295 100644
--- a/hotspot/src/share/vm/opto/phaseX.hpp
+++ b/hotspot/src/share/vm/opto/phaseX.hpp
@@ -327,6 +327,9 @@ public:
                                const Type* limit_type) const
   { ShouldNotCallThis(); return NULL; }
 
+  // Delayed node rehash if this is an IGVN phase
+  virtual void igvn_rehash_node_delayed(Node* n) {}
+
   virtual PhaseIterGVN *is_IterGVN() { return 0; }
 
 #ifndef PRODUCT
@@ -495,7 +498,11 @@ public:
     _worklist.push(n);
   }
 
-  // Replace ith edge of "n" with "in"
+  void igvn_rehash_node_delayed(Node* n) {
+    rehash_node_delayed(n);
+  }
+
+    // Replace ith edge of "n" with "in"
   void replace_input_of(Node* n, int i, Node* in) {
     rehash_node_delayed(n);
     n->set_req(i, in);
diff --git a/hotspot/test/compiler/loopopts/TestMoveStoresOutOfLoops.java b/hotspot/test/compiler/loopopts/TestMoveStoresOutOfLoops.java
new file mode 100644
index 000000000..4eea5d5e4
--- /dev/null
+++ b/hotspot/test/compiler/loopopts/TestMoveStoresOutOfLoops.java
@@ -0,0 +1,310 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. 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 8080289
+ * @summary Sink stores out of loops if possible
+ * @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:+PrintCompilation -XX:CompileCommand=dontinline,TestMoveStoresOutOfLoops::test*  TestMoveStoresOutOfLoops
+ *
+ */
+
+import java.lang.reflect.*;
+import java.util.*;
+import java.util.function.*;
+
+public class TestMoveStoresOutOfLoops {
+
+    private static long[] array = new long[10];
+    private static long[] array2 = new long[10];
+    private static boolean[] array3 = new boolean[1000];
+    private static byte[] byte_array = new byte[10];
+
+    // Array store should be moved out of the loop, value stored
+    // should be 999, the loop should be eliminated
+    static void test_after_1(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = i;
+        }
+    }
+
+    // Array store can't be moved out of loop because of following
+    // non loop invariant array access
+    static void test_after_2(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = i;
+            array2[i%10] = i;
+        }
+    }
+
+    // Array store can't be moved out of loop because of following
+    // use
+    static void test_after_3(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = i;
+            if (array[0] == -1) {
+                break;
+            }
+        }
+    }
+
+    // Array store can't be moved out of loop because of preceding
+    // use
+    static void test_after_4(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            if (array[0] == -2) {
+                break;
+            }
+            array[idx] = i;
+        }
+    }
+
+    // All array stores should be moved out of the loop, one after
+    // the other
+    static void test_after_5(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = i;
+            array[idx+1] = i;
+            array[idx+2] = i;
+            array[idx+3] = i;
+            array[idx+4] = i;
+            array[idx+5] = i;
+        }
+    }
+
+    // Array store can be moved after the loop but needs to be
+    // cloned on both exit paths
+    static void test_after_6(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = i;
+            if (array3[i]) {
+                return;
+            }
+        }
+    }
+
+    // Optimize out redundant stores
+    static void test_stores_1(int ignored) {
+        array[0] = 0;
+        array[1] = 1;
+        array[2] = 2;
+        array[0] = 0;
+        array[1] = 1;
+        array[2] = 2;
+    }
+
+    static void test_stores_2(int idx) {
+        array[idx+0] = 0;
+        array[idx+1] = 1;
+        array[idx+2] = 2;
+        array[idx+0] = 0;
+        array[idx+1] = 1;
+        array[idx+2] = 2;
+    }
+
+    static void test_stores_3(int idx) {
+        byte_array[idx+0] = 0;
+        byte_array[idx+1] = 1;
+        byte_array[idx+2] = 2;
+        byte_array[idx+0] = 0;
+        byte_array[idx+1] = 1;
+        byte_array[idx+2] = 2;
+    }
+
+    // Array store can be moved out of the loop before the loop header
+    static void test_before_1(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = 999;
+        }
+    }
+
+    // Array store can't be moved out of the loop before the loop
+    // header because there's more than one store on this slice
+    static void test_before_2(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            array[idx] = 999;
+            array[i%2] = 0;
+        }
+    }
+
+    // Array store can't be moved out of the loop before the loop
+    // header because of use before store
+    static int test_before_3(int idx) {
+        int res = 0;
+        for (int i = 0; i < 1000; i++) {
+            res += array[i%10];
+            array[idx] = 999;
+        }
+        return res;
+    }
+
+    // Array store can't be moved out of the loop before the loop
+    // header because of possible early exit
+    static void test_before_4(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            if (idx / (i+1) > 0) {
+                return;
+            }
+            array[idx] = 999;
+        }
+    }
+
+    // Array store can't be moved out of the loop before the loop
+    // header because it doesn't postdominate the loop head
+    static void test_before_5(int idx) {
+        for (int i = 0; i < 1000; i++) {
+            if (i % 2 == 0) {
+                array[idx] = 999;
+            }
+        }
+    }
+
+    // Array store can be moved out of the loop before the loop header
+    static int test_before_6(int idx) {
+        int res = 0;
+        for (int i = 0; i < 1000; i++) {
+            if (i%2 == 1) {
+                res *= 2;
+            } else {
+                res++;
+            }
+            array[idx] = 999;
+        }
+        return res;
+    }
+
+    final HashMap<String,Method> tests = new HashMap<>();
+    {
+        for (Method m : this.getClass().getDeclaredMethods()) {
+            if (m.getName().matches("test_(before|after|stores)_[0-9]+")) {
+                assert(Modifier.isStatic(m.getModifiers())) : m;
+                tests.put(m.getName(), m);
+            }
+        }
+    }
+
+    boolean success = true;
+    void doTest(String name, Runnable init, Function<String, Boolean> check) throws Exception {
+        Method m = tests.get(name);
+        for (int i = 0; i < 20000; i++) {
+            init.run();
+            m.invoke(null, 0);
+            success = success && check.apply(name);
+            if (!success) {
+                break;
+            }
+        }
+    }
+
+    static void array_init() {
+        array[0] = -1;
+    }
+
+    static boolean array_check(String name) {
+        boolean success = true;
+        if (array[0] != 999) {
+            success = false;
+            System.out.println(name + " failed: array[0] = " + array[0]);
+        }
+        return success;
+    }
+
+    static void array_init2() {
+        for (int i = 0; i < 6; i++) {
+            array[i] = -1;
+        }
+    }
+
+    static boolean array_check2(String name) {
+        boolean success = true;
+        for (int i = 0; i < 6; i++) {
+            if (array[i] != 999) {
+                success = false;
+                System.out.println(name + " failed: array[" + i + "] = " + array[i]);
+            }
+        }
+        return success;
+    }
+
+    static void array_init3() {
+        for (int i = 0; i < 3; i++) {
+            array[i] = -1;
+        }
+    }
+
+    static boolean array_check3(String name) {
+        boolean success = true;
+        for (int i = 0; i < 3; i++) {
+            if (array[i] != i) {
+                success = false;
+                System.out.println(name + " failed: array[" + i + "] = " + array[i]);
+            }
+        }
+        return success;
+    }
+
+    static void array_init4() {
+        for (int i = 0; i < 3; i++) {
+            byte_array[i] = -1;
+        }
+    }
+
+    static boolean array_check4(String name) {
+        boolean success = true;
+        for (int i = 0; i < 3; i++) {
+            if (byte_array[i] != i) {
+                success = false;
+                System.out.println(name + " failed: byte_array[" + i + "] = " + byte_array[i]);
+            }
+        }
+        return success;
+    }
+
+    static public void main(String[] args) throws Exception {
+        TestMoveStoresOutOfLoops test = new TestMoveStoresOutOfLoops();
+        test.doTest("test_after_1", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_after_2", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_after_3", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_after_4", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_after_5", TestMoveStoresOutOfLoops::array_init2, TestMoveStoresOutOfLoops::array_check2);
+        test.doTest("test_after_6", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        array3[999] = true;
+        test.doTest("test_after_6", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+
+        test.doTest("test_stores_1", TestMoveStoresOutOfLoops::array_init3, TestMoveStoresOutOfLoops::array_check3);
+        test.doTest("test_stores_2", TestMoveStoresOutOfLoops::array_init3, TestMoveStoresOutOfLoops::array_check3);
+        test.doTest("test_stores_3", TestMoveStoresOutOfLoops::array_init4, TestMoveStoresOutOfLoops::array_check4);
+
+        test.doTest("test_before_1", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_before_2", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_before_3", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_before_4", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_before_5", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+        test.doTest("test_before_6", TestMoveStoresOutOfLoops::array_init, TestMoveStoresOutOfLoops::array_check);
+
+        if (!test.success) {
+            throw new RuntimeException("Some tests failed");
+        }
+    }
+}
-- 
2.19.1