8264063: Outer Safepoint poll load should not reference the head of inner strip mined loop.

Reviewed-by: roland, vlivanov

Author: Vladimir Kozlov

src/hotspot/cpu/aarch64/aarch64.ad

@@ -1782,20 +1782,6 @@ int MachCallNativeNode::ret_addr_offset() {
   }
 }
 
-// Indicate if the safepoint node needs the polling page as an input
-
-// the shared code plants the oop data at the start of the generated
-// code for the safepoint node and that needs ot be at the load
-// instruction itself. so we cannot plant a mov of the safepoint poll
-// address followed by a load. setting this to true means the mov is
-// scheduled as a prior instruction. that's better for scheduling
-// anyway.
-
-bool SafePointNode::needs_polling_address_input()
-{
-  return true;
-}
-
 //=============================================================================
 
 #ifndef PRODUCT

src/hotspot/cpu/arm/arm.ad

@@ -146,12 +146,6 @@ int MachNode::compute_padding(int current_offset) const {
 
 // REQUIRED FUNCTIONALITY
 
-// Indicate if the safepoint node needs the polling page as an input.
-// Since ARM does not have absolute addressing, it does.
-bool SafePointNode::needs_polling_address_input() {
-  return true;
-}
-
 // emit an interrupt that is caught by the debugger (for debugging compiler)
 void emit_break(CodeBuffer &cbuf) {
   C2_MacroAssembler _masm(&cbuf);

src/hotspot/cpu/ppc/ppc.ad

@@ -1159,14 +1159,6 @@ static int cc_to_biint(int cc, int flags_reg) {
 
 //=============================================================================
 
-// Indicate if the safepoint node needs the polling page as an input.
-bool SafePointNode::needs_polling_address_input() {
-  // The address is loaded from thread by a seperate node.
-  return true;
-}
-
-//=============================================================================
-
 // Emit an interrupt that is caught by the debugger (for debugging compiler).
 void emit_break(CodeBuffer &cbuf) {
   C2_MacroAssembler _masm(&cbuf);

src/hotspot/cpu/s390/s390.ad

@@ -671,12 +671,6 @@ int CallLeafNoFPDirectNode::compute_padding(int current_offset) const {
   return (12 - current_offset) & 2;
 }
 
-// Indicate if the safepoint node needs the polling page as an input.
-// Since z/Architecture does not have absolute addressing, it does.
-bool SafePointNode::needs_polling_address_input() {
-  return true;
-}
-
 void emit_nop(CodeBuffer &cbuf) {
   C2_MacroAssembler _masm(&cbuf);
   __ z_nop();

src/hotspot/share/opto/callnode.hpp

@@ -484,8 +484,6 @@ class SafePointNode : public MultiNode {
   virtual const RegMask &out_RegMask() const;
   virtual uint           match_edge(uint idx) const;
 
-  static  bool           needs_polling_address_input();
-
 #ifndef PRODUCT
   virtual void           dump_spec(outputStream *st) const;
   virtual void           related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const;

src/hotspot/share/opto/loopTransform.cpp

@@ -3701,16 +3701,6 @@ bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& st
     for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) {
       Node* use = iter.get();
       if (!lpt->_body.contains(use)) {
-        if (n->is_CountedLoop() && n->as_CountedLoop()->is_strip_mined()) {
-          // In strip-mined counted loops, the CountedLoopNode may be
-          // used by the address polling node of the outer safepoint.
-          // Skip this use because it's safe.
-          Node* sfpt = n->as_CountedLoop()->outer_safepoint();
-          Node* polladr = sfpt->in(TypeFunc::Parms+0);
-          if (use == polladr) {
-            continue;
-          }
-        }
         msg = "node is used outside loop";
         msg_node = n;
         break;

src/hotspot/share/opto/loopnode.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2021, 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
@@ -1638,6 +1638,16 @@ bool PhaseIdealLoop::is_counted_loop(Node* x, IdealLoopTree*&loop, BasicType iv_
         Node* sfpt = sfpt2->clone();
         sfpt->set_req(0, iffalse);
         outer_le->set_req(0, sfpt);
+
+        Node* polladdr = sfpt->in(TypeFunc::Parms);
+        if (polladdr != nullptr && polladdr->is_Load()) {
+          // Polling load should be pinned outside inner loop.
+          Node* new_polladdr = polladdr->clone();
+          new_polladdr->set_req(0, iffalse);
+          _igvn.register_new_node_with_optimizer(new_polladdr, polladdr);
+          set_ctrl(new_polladdr, iffalse);
+          sfpt->set_req(TypeFunc::Parms, new_polladdr);
+        }
         // When this code runs, loop bodies have not yet been populated.
         const bool body_populated = false;
         register_control(sfpt, outer_ilt, iffalse, body_populated);