JohnTortugo

@only 169 156 273 260 258 204 203 251 200 190 99 97 53 42 40 39 27
@only 158 207 202 44 39

   0  Root  === 0 113 125 136 147 173 271 272  [[ 0 1 3 23 24 25 47 186 185 181 161 142 87 108 115 120 131 275 ]] 
   1  Con  === 0  [[ ]]  #top
   3  Start  === 3 0  [[ 3 5 6 7 8 9 10 11 ]]  #{0:control, 1:abIO, 2:memory, 3:rawptr:BotPTR, 4:return_address, 5:int, 6:int}
  23  ConI  === 0  [[ 190 27 27 143 157 132 121 121 101 183 190 143 143 132 132 121 ]]  #int:0
  24  ConP  === 0  [[ 27 190 ]]  #precise TestIncorrectRemat$MyClass: 0x00007ffff04f1578:Constant:exact *  Klass:precise TestIncorrectRemat$MyClass: 0x00007ffff04f1578:Constant:exact *
  25  ConL  === 0  [[ 27 190 ]]  #long:16
  47  ConI  === 0  [[ 251 90 ]]  #int:42

JohnTortugo

diff --git a/src/hotspot/share/code/debugInfo.cpp b/src/hotspot/share/code/debugInfo.cpp
index 55d12448deb..404df71a4a6 100644
--- a/src/hotspot/share/code/debugInfo.cpp
+++ b/src/hotspot/share/code/debugInfo.cpp
@@ -243,7 +243,10 @@ void ObjectValue::print_fields_on(outputStream* st) const {
 ObjectValue* ObjectMergeValue::select(frame& fr, RegisterMap& reg_map) {
   StackValue* sv_selector = StackValue::create_stack_value(&fr, &reg_map, _selector);
   jint selector = sv_selector->get_int();
-
+  tty->print_cr("_selector is location: %d",_selector->is_location());

JohnTortugo

Compiled method (c2)     504   48             TestObjectClone::test (37 bytes)
 total in heap  [0x00007f4ba915d110,0x00007f4ba915d568] = 1112
 relocation     [0x00007f4ba915d280,0x00007f4ba915d2a8] = 40
 main code      [0x00007f4ba915d2c0,0x00007f4ba915d3d0] = 272
 stub code      [0x00007f4ba915d3d0,0x00007f4ba915d3e8] = 24
 oops           [0x00007f4ba915d3e8,0x00007f4ba915d3f8] = 16
 metadata       [0x00007f4ba915d3f8,0x00007f4ba915d410] = 24
 scopes data    [0x00007f4ba915d410,0x00007f4ba915d4b0] = 160
 scopes pcs     [0x00007f4ba915d4b0,0x00007f4ba915d560] = 176
 dependencies   [0x00007f4ba915d560,0x00007f4ba915d568] = 8

JohnTortugo

HotSpot Escape Analysis and Scalar Replacement Status

Introduction

Escape Analysis (EA) is a compiler analysis to answer the following questions for a given object O, method M, and thread T.

• Escapes(O, M): Does object O outlive the execution of method M? This may happen for instance if a reference to O is assigned to a global variable.
• Escapes(O, T): Does object O escape the current execution thread? This may happen for instance if a reference to O is copied to another thread.

Answers to these questions enable a compiler to perform a few highly effective optimizations, for instance, Stack Allocation (SA), Lock Elision (LE), and Scalar Replacement of Aggregates (SRA). Note that,

JohnTortugo

/*
 * Copyright (c) 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
 * 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