1 /*
   2  * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23  */
  24 
  25 #include "compiler/compileLog.hpp"
  26 #include "gc/shared/barrierSet.hpp"
  27 #include "gc/shared/c2/barrierSetC2.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "opto/addnode.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/loopnode.hpp"
  33 #include "opto/matcher.hpp"
  34 #include "opto/movenode.hpp"
  35 #include "opto/mulnode.hpp"
  36 #include "opto/opaquenode.hpp"
  37 #include "opto/opcodes.hpp"
  38 #include "opto/phaseX.hpp"
  39 #include "opto/subnode.hpp"
  40 #include "runtime/sharedRuntime.hpp"
  41 #include "utilities/reverse_bits.hpp"
  42 
  43 // Portions of code courtesy of Clifford Click
  44 
  45 // Optimization - Graph Style
  46 
  47 #include "math.h"
  48 
  49 //=============================================================================
  50 //------------------------------Identity---------------------------------------
  51 // If right input is a constant 0, return the left input.
  52 Node* SubNode::Identity(PhaseGVN* phase) {
  53   assert(in(1) != this, "Must already have called Value");
  54   assert(in(2) != this, "Must already have called Value");
  55 
  56   const Type* zero = add_id();
  57 
  58   // Remove double negation if it is not a floating point number since negation
  59   // is not the same as subtraction for floating point numbers
  60   // (cf. JLS § 15.15.4). `0-(0-(-0.0))` must be equal to positive 0.0 according to
  61   // JLS § 15.8.2, but would result in -0.0 if this folding would be applied.
  62   if (phase->type(in(1))->higher_equal(zero) &&
  63       in(2)->Opcode() == Opcode() &&
  64       phase->type(in(2)->in(1))->higher_equal(zero) &&
  65       !phase->type(in(2)->in(2))->is_floatingpoint()) {
  66     return in(2)->in(2);
  67   }
  68 
  69   // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y
  70   if (in(1)->Opcode() == Op_AddI || in(1)->Opcode() == Op_AddL) {
  71     if (in(1)->in(2) == in(2)) {
  72       return in(1)->in(1);
  73     }
  74     if (in(1)->in(1) == in(2)) {
  75       return in(1)->in(2);
  76     }
  77   }
  78 
  79   return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this;
  80 }
  81 
  82 //------------------------------Value------------------------------------------
  83 // A subtract node differences it's two inputs.
  84 const Type* SubNode::Value_common(PhaseValues* phase) const {
  85   const Node* in1 = in(1);
  86   const Node* in2 = in(2);
  87   // Either input is TOP ==> the result is TOP
  88   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  89   if( t1 == Type::TOP ) return Type::TOP;
  90   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  91   if( t2 == Type::TOP ) return Type::TOP;
  92 
  93   // Not correct for SubFnode and AddFNode (must check for infinity)
  94   // Equal?  Subtract is zero
  95   if (in1->eqv_uncast(in2))  return add_id();
  96 
  97   // Either input is BOTTOM ==> the result is the local BOTTOM
  98   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
  99     return bottom_type();
 100 
 101   return nullptr;
 102 }
 103 
 104 const Type* SubNode::Value(PhaseGVN* phase) const {
 105   const Type* t = Value_common(phase);
 106   if (t != nullptr) {
 107     return t;
 108   }
 109   const Type* t1 = phase->type(in(1));
 110   const Type* t2 = phase->type(in(2));
 111   return sub(t1,t2);            // Local flavor of type subtraction
 112 
 113 }
 114 
 115 SubNode* SubNode::make(Node* in1, Node* in2, BasicType bt) {
 116   switch (bt) {
 117     case T_INT:
 118       return new SubINode(in1, in2);
 119     case T_LONG:
 120       return new SubLNode(in1, in2);
 121     default:
 122       fatal("Not implemented for %s", type2name(bt));
 123   }
 124   return nullptr;
 125 }
 126 
 127 //=============================================================================
 128 //------------------------------Helper function--------------------------------
 129 
 130 static bool is_cloop_increment(Node* inc) {
 131   precond(inc->Opcode() == Op_AddI || inc->Opcode() == Op_AddL);
 132 
 133   if (!inc->in(1)->is_Phi()) {
 134     return false;
 135   }
 136   const PhiNode* phi = inc->in(1)->as_Phi();
 137 
 138   if (!phi->region()->is_CountedLoop()) {
 139     return false;
 140   }
 141 
 142   return inc == phi->region()->as_CountedLoop()->incr();
 143 }
 144 
 145 // Given the expression '(x + C) - v', or
 146 //                      'v - (x + C)', we examine nodes '+' and 'v':
 147 //
 148 //  1. Do not convert if '+' is a counted-loop increment, because the '-' is
 149 //     loop invariant and converting extends the live-range of 'x' to overlap
 150 //     with the '+', forcing another register to be used in the loop.
 151 //
 152 //  2. Do not convert if 'v' is a counted-loop induction variable, because
 153 //     'x' might be invariant.
 154 //
 155 static bool ok_to_convert(Node* inc, Node* var) {
 156   return !(is_cloop_increment(inc) || var->is_cloop_ind_var());
 157 }
 158 
 159 static bool is_cloop_condition(BoolNode* bol) {
 160   for (DUIterator_Fast imax, i = bol->fast_outs(imax); i < imax; i++) {
 161     Node* out = bol->fast_out(i);
 162     if (out->is_BaseCountedLoopEnd()) {
 163       return true;
 164     }
 165   }
 166   return false;
 167 }
 168 
 169 //------------------------------Ideal------------------------------------------
 170 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
 171   Node *in1 = in(1);
 172   Node *in2 = in(2);
 173   uint op1 = in1->Opcode();
 174   uint op2 = in2->Opcode();
 175 
 176 #ifdef ASSERT
 177   // Check for dead loop
 178   if ((in1 == this) || (in2 == this) ||
 179       ((op1 == Op_AddI || op1 == Op_SubI) &&
 180        ((in1->in(1) == this) || (in1->in(2) == this) ||
 181         (in1->in(1) == in1)  || (in1->in(2) == in1)))) {
 182     assert(false, "dead loop in SubINode::Ideal");
 183   }
 184 #endif
 185 
 186   const Type *t2 = phase->type( in2 );
 187   if( t2 == Type::TOP ) return nullptr;
 188   // Convert "x-c0" into "x+ -c0".
 189   if( t2->base() == Type::Int ){        // Might be bottom or top...
 190     const TypeInt *i = t2->is_int();
 191     if( i->is_con() )
 192       return new AddINode(in1, phase->intcon(java_negate(i->get_con())));
 193   }
 194 
 195   // Convert "(x+c0) - y" into (x-y) + c0"
 196   // Do not collapse (x+c0)-y if "+" is a loop increment or
 197   // if "y" is a loop induction variable.
 198   if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
 199     const Type *tadd = phase->type( in1->in(2) );
 200     if( tadd->singleton() && tadd != Type::TOP ) {
 201       Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 ));
 202       return new AddINode( sub2, in1->in(2) );
 203     }
 204   }
 205 
 206   // Convert "x - (y+c0)" into "(x-y) - c0" AND
 207   // Convert "c1 - (y+c0)" into "(c1-c0) - y"
 208   // Need the same check as in above optimization but reversed.
 209   if (op2 == Op_AddI
 210       && ok_to_convert(in2, in1)
 211       && in2->in(2)->Opcode() == Op_ConI) {
 212     jint c0 = phase->type(in2->in(2))->isa_int()->get_con();
 213     Node* in21 = in2->in(1);
 214     if (in1->Opcode() == Op_ConI) {
 215       // Match c1
 216       jint c1 = phase->type(in1)->isa_int()->get_con();
 217       Node* sub2 = phase->intcon(java_subtract(c1, c0));
 218       return new SubINode(sub2, in21);
 219     } else {
 220       // Match x
 221       Node* sub2 = phase->transform(new SubINode(in1, in21));
 222       Node* neg_c0 = phase->intcon(java_negate(c0));
 223       return new AddINode(sub2, neg_c0);
 224     }
 225   }
 226 
 227   const Type *t1 = phase->type( in1 );
 228   if( t1 == Type::TOP ) return nullptr;
 229 
 230 #ifdef ASSERT
 231   // Check for dead loop
 232   if ((op2 == Op_AddI || op2 == Op_SubI) &&
 233       ((in2->in(1) == this) || (in2->in(2) == this) ||
 234        (in2->in(1) == in2)  || (in2->in(2) == in2))) {
 235     assert(false, "dead loop in SubINode::Ideal");
 236   }
 237 #endif
 238 
 239   // Convert "x - (x+y)" into "-y"
 240   if (op2 == Op_AddI && in1 == in2->in(1)) {
 241     return new SubINode(phase->intcon(0), in2->in(2));
 242   }
 243   // Convert "(x-y) - x" into "-y"
 244   if (op1 == Op_SubI && in1->in(1) == in2) {
 245     return new SubINode(phase->intcon(0), in1->in(2));
 246   }
 247   // Convert "x - (y+x)" into "-y"
 248   if (op2 == Op_AddI && in1 == in2->in(2)) {
 249     return new SubINode(phase->intcon(0), in2->in(1));
 250   }
 251 
 252   // Convert "0 - (x-y)" into "y-x", leave the double negation "-(-y)" to SubNode::Identity().
 253   if (t1 == TypeInt::ZERO && op2 == Op_SubI && phase->type(in2->in(1)) != TypeInt::ZERO) {
 254     return new SubINode(in2->in(2), in2->in(1));
 255   }
 256 
 257   // Convert "0 - (x+con)" into "-con-x"
 258   jint con;
 259   if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
 260       (con = in2->in(2)->find_int_con(0)) != 0 )
 261     return new SubINode( phase->intcon(-con), in2->in(1) );
 262 
 263   // Convert "(X+A) - (X+B)" into "A - B"
 264   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
 265     return new SubINode( in1->in(2), in2->in(2) );
 266 
 267   // Convert "(A+X) - (B+X)" into "A - B"
 268   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
 269     return new SubINode( in1->in(1), in2->in(1) );
 270 
 271   // Convert "(A+X) - (X+B)" into "A - B"
 272   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
 273     return new SubINode( in1->in(1), in2->in(2) );
 274 
 275   // Convert "(X+A) - (B+X)" into "A - B"
 276   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
 277     return new SubINode( in1->in(2), in2->in(1) );
 278 
 279   // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
 280   // nicer to optimize than subtract.
 281   if( op2 == Op_SubI && in2->outcnt() == 1) {
 282     Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) );
 283     return new SubINode( add1, in2->in(1) );
 284   }
 285 
 286   // Associative
 287   if (op1 == Op_MulI && op2 == Op_MulI) {
 288     Node* sub_in1 = nullptr;
 289     Node* sub_in2 = nullptr;
 290     Node* mul_in = nullptr;
 291 
 292     if (in1->in(1) == in2->in(1)) {
 293       // Convert "a*b-a*c into a*(b-c)
 294       sub_in1 = in1->in(2);
 295       sub_in2 = in2->in(2);
 296       mul_in = in1->in(1);
 297     } else if (in1->in(2) == in2->in(1)) {
 298       // Convert a*b-b*c into b*(a-c)
 299       sub_in1 = in1->in(1);
 300       sub_in2 = in2->in(2);
 301       mul_in = in1->in(2);
 302     } else if (in1->in(2) == in2->in(2)) {
 303       // Convert a*c-b*c into (a-b)*c
 304       sub_in1 = in1->in(1);
 305       sub_in2 = in2->in(1);
 306       mul_in = in1->in(2);
 307     } else if (in1->in(1) == in2->in(2)) {
 308       // Convert a*b-c*a into a*(b-c)
 309       sub_in1 = in1->in(2);
 310       sub_in2 = in2->in(1);
 311       mul_in = in1->in(1);
 312     }
 313 
 314     if (mul_in != nullptr) {
 315       Node* sub = phase->transform(new SubINode(sub_in1, sub_in2));
 316       return new MulINode(mul_in, sub);
 317     }
 318   }
 319 
 320   // Convert "0-(A>>31)" into "(A>>>31)"
 321   if ( op2 == Op_RShiftI ) {
 322     Node *in21 = in2->in(1);
 323     Node *in22 = in2->in(2);
 324     const TypeInt *zero = phase->type(in1)->isa_int();
 325     const TypeInt *t21 = phase->type(in21)->isa_int();
 326     const TypeInt *t22 = phase->type(in22)->isa_int();
 327     if ( t21 && t22 && zero == TypeInt::ZERO && t22->is_con(31) ) {
 328       return new URShiftINode(in21, in22);
 329     }
 330   }
 331 
 332   return nullptr;
 333 }
 334 
 335 //------------------------------sub--------------------------------------------
 336 // A subtract node differences it's two inputs.
 337 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
 338   const TypeInt *r0 = t1->is_int(); // Handy access
 339   const TypeInt *r1 = t2->is_int();
 340   int32_t lo = java_subtract(r0->_lo, r1->_hi);
 341   int32_t hi = java_subtract(r0->_hi, r1->_lo);
 342 
 343   // We next check for 32-bit overflow.
 344   // If that happens, we just assume all integers are possible.
 345   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 346        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 347       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 348        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 349     return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 350   else                          // Overflow; assume all integers
 351     return TypeInt::INT;
 352 }
 353 
 354 //=============================================================================
 355 //------------------------------Ideal------------------------------------------
 356 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 357   Node *in1 = in(1);
 358   Node *in2 = in(2);
 359   uint op1 = in1->Opcode();
 360   uint op2 = in2->Opcode();
 361 
 362 #ifdef ASSERT
 363   // Check for dead loop
 364   if ((in1 == this) || (in2 == this) ||
 365       ((op1 == Op_AddL || op1 == Op_SubL) &&
 366        ((in1->in(1) == this) || (in1->in(2) == this) ||
 367         (in1->in(1) == in1)  || (in1->in(2) == in1)))) {
 368     assert(false, "dead loop in SubLNode::Ideal");
 369   }
 370 #endif
 371 
 372   if( phase->type( in2 ) == Type::TOP ) return nullptr;
 373   const TypeLong *i = phase->type( in2 )->isa_long();
 374   // Convert "x-c0" into "x+ -c0".
 375   if( i &&                      // Might be bottom or top...
 376       i->is_con() )
 377     return new AddLNode(in1, phase->longcon(java_negate(i->get_con())));
 378 
 379   // Convert "(x+c0) - y" into (x-y) + c0"
 380   // Do not collapse (x+c0)-y if "+" is a loop increment or
 381   // if "y" is a loop induction variable.
 382   if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
 383     Node *in11 = in1->in(1);
 384     const Type *tadd = phase->type( in1->in(2) );
 385     if( tadd->singleton() && tadd != Type::TOP ) {
 386       Node *sub2 = phase->transform( new SubLNode( in11, in2 ));
 387       return new AddLNode( sub2, in1->in(2) );
 388     }
 389   }
 390 
 391   // Convert "x - (y+c0)" into "(x-y) - c0" AND
 392   // Convert "c1 - (y+c0)" into "(c1-c0) - y"
 393   // Need the same check as in above optimization but reversed.
 394   if (op2 == Op_AddL
 395       && ok_to_convert(in2, in1)
 396       && in2->in(2)->Opcode() == Op_ConL) {
 397     jlong c0 = phase->type(in2->in(2))->isa_long()->get_con();
 398     Node* in21 = in2->in(1);
 399     if (in1->Opcode() == Op_ConL) {
 400       // Match c1
 401       jlong c1 = phase->type(in1)->isa_long()->get_con();
 402       Node* sub2 = phase->longcon(java_subtract(c1, c0));
 403       return new SubLNode(sub2, in21);
 404     } else {
 405       Node* sub2 = phase->transform(new SubLNode(in1, in21));
 406       Node* neg_c0 = phase->longcon(-c0);
 407       return new AddLNode(sub2, neg_c0);
 408     }
 409   }
 410 
 411   const Type *t1 = phase->type( in1 );
 412   if( t1 == Type::TOP ) return nullptr;
 413 
 414 #ifdef ASSERT
 415   // Check for dead loop
 416   if ((op2 == Op_AddL || op2 == Op_SubL) &&
 417       ((in2->in(1) == this) || (in2->in(2) == this) ||
 418        (in2->in(1) == in2)  || (in2->in(2) == in2))) {
 419     assert(false, "dead loop in SubLNode::Ideal");
 420   }
 421 #endif
 422 
 423   // Convert "x - (x+y)" into "-y"
 424   if (op2 == Op_AddL && in1 == in2->in(1)) {
 425     return new SubLNode(phase->makecon(TypeLong::ZERO), in2->in(2));
 426   }
 427   // Convert "(x-y) - x" into "-y"
 428   if (op1 == Op_SubL && in1->in(1) == in2) {
 429     return new SubLNode(phase->makecon(TypeLong::ZERO), in1->in(2));
 430   }
 431   // Convert "x - (y+x)" into "-y"
 432   if (op2 == Op_AddL && in1 == in2->in(2)) {
 433     return new SubLNode(phase->makecon(TypeLong::ZERO), in2->in(1));
 434   }
 435 
 436   // Convert "0 - (x-y)" into "y-x", leave the double negation "-(-y)" to SubNode::Identity.
 437   if (t1 == TypeLong::ZERO && op2 == Op_SubL && phase->type(in2->in(1)) != TypeLong::ZERO) {
 438     return new SubLNode(in2->in(2), in2->in(1));
 439   }
 440 
 441   // Convert "(X+A) - (X+B)" into "A - B"
 442   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
 443     return new SubLNode( in1->in(2), in2->in(2) );
 444 
 445   // Convert "(A+X) - (B+X)" into "A - B"
 446   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
 447     return new SubLNode( in1->in(1), in2->in(1) );
 448 
 449   // Convert "(A+X) - (X+B)" into "A - B"
 450   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(1) )
 451     return new SubLNode( in1->in(1), in2->in(2) );
 452 
 453   // Convert "(X+A) - (B+X)" into "A - B"
 454   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(2) )
 455     return new SubLNode( in1->in(2), in2->in(1) );
 456 
 457   // Convert "A-(B-C)" into (A+C)-B"
 458   if( op2 == Op_SubL && in2->outcnt() == 1) {
 459     Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) );
 460     return new SubLNode( add1, in2->in(1) );
 461   }
 462 
 463   // Associative
 464   if (op1 == Op_MulL && op2 == Op_MulL) {
 465     Node* sub_in1 = nullptr;
 466     Node* sub_in2 = nullptr;
 467     Node* mul_in = nullptr;
 468 
 469     if (in1->in(1) == in2->in(1)) {
 470       // Convert "a*b-a*c into a*(b+c)
 471       sub_in1 = in1->in(2);
 472       sub_in2 = in2->in(2);
 473       mul_in = in1->in(1);
 474     } else if (in1->in(2) == in2->in(1)) {
 475       // Convert a*b-b*c into b*(a-c)
 476       sub_in1 = in1->in(1);
 477       sub_in2 = in2->in(2);
 478       mul_in = in1->in(2);
 479     } else if (in1->in(2) == in2->in(2)) {
 480       // Convert a*c-b*c into (a-b)*c
 481       sub_in1 = in1->in(1);
 482       sub_in2 = in2->in(1);
 483       mul_in = in1->in(2);
 484     } else if (in1->in(1) == in2->in(2)) {
 485       // Convert a*b-c*a into a*(b-c)
 486       sub_in1 = in1->in(2);
 487       sub_in2 = in2->in(1);
 488       mul_in = in1->in(1);
 489     }
 490 
 491     if (mul_in != nullptr) {
 492       Node* sub = phase->transform(new SubLNode(sub_in1, sub_in2));
 493       return new MulLNode(mul_in, sub);
 494     }
 495   }
 496 
 497   // Convert "0L-(A>>63)" into "(A>>>63)"
 498   if ( op2 == Op_RShiftL ) {
 499     Node *in21 = in2->in(1);
 500     Node *in22 = in2->in(2);
 501     const TypeLong *zero = phase->type(in1)->isa_long();
 502     const TypeLong *t21 = phase->type(in21)->isa_long();
 503     const TypeInt *t22 = phase->type(in22)->isa_int();
 504     if ( t21 && t22 && zero == TypeLong::ZERO && t22->is_con(63) ) {
 505       return new URShiftLNode(in21, in22);
 506     }
 507   }
 508 
 509   return nullptr;
 510 }
 511 
 512 //------------------------------sub--------------------------------------------
 513 // A subtract node differences it's two inputs.
 514 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
 515   const TypeLong *r0 = t1->is_long(); // Handy access
 516   const TypeLong *r1 = t2->is_long();
 517   jlong lo = java_subtract(r0->_lo, r1->_hi);
 518   jlong hi = java_subtract(r0->_hi, r1->_lo);
 519 
 520   // We next check for 32-bit overflow.
 521   // If that happens, we just assume all integers are possible.
 522   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 523        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 524       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 525        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 526     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 527   else                          // Overflow; assume all integers
 528     return TypeLong::LONG;
 529 }
 530 
 531 //=============================================================================
 532 //------------------------------Value------------------------------------------
 533 // A subtract node differences its two inputs.
 534 const Type* SubFPNode::Value(PhaseGVN* phase) const {
 535   const Node* in1 = in(1);
 536   const Node* in2 = in(2);
 537   // Either input is TOP ==> the result is TOP
 538   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 539   if( t1 == Type::TOP ) return Type::TOP;
 540   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 541   if( t2 == Type::TOP ) return Type::TOP;
 542 
 543   // if both operands are infinity of same sign, the result is NaN; do
 544   // not replace with zero
 545   if (t1->is_finite() && t2->is_finite() && in1 == in2) {
 546     return add_id();
 547   }
 548 
 549   // Either input is BOTTOM ==> the result is the local BOTTOM
 550   const Type *bot = bottom_type();
 551   if( (t1 == bot) || (t2 == bot) ||
 552       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 553     return bot;
 554 
 555   return sub(t1,t2);            // Local flavor of type subtraction
 556 }
 557 
 558 
 559 //=============================================================================
 560 //------------------------------sub--------------------------------------------
 561 // A subtract node differences its two inputs.
 562 const Type* SubHFNode::sub(const Type* t1, const Type* t2) const {
 563   // no folding if one of operands is infinity or NaN, do not do constant folding
 564   if(g_isfinite(t1->getf()) && g_isfinite(t2->getf())) {
 565     return TypeH::make(t1->getf() - t2->getf());
 566   }
 567   else if(g_isnan(t1->getf())) {
 568     return t1;
 569   }
 570   else if(g_isnan(t2->getf())) {
 571     return t2;
 572   }
 573   else {
 574     return Type::HALF_FLOAT;
 575   }
 576 }
 577 
 578 //------------------------------Ideal------------------------------------------
 579 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 580   const Type *t2 = phase->type( in(2) );
 581   // Convert "x-c0" into "x+ -c0".
 582   if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
 583     // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
 584   }
 585 
 586   // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
 587   // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
 588   //if( phase->type(in(1)) == TypeF::ZERO )
 589   //return new (phase->C, 2) NegFNode(in(2));
 590 
 591   return nullptr;
 592 }
 593 
 594 //------------------------------sub--------------------------------------------
 595 // A subtract node differences its two inputs.
 596 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
 597   // no folding if one of operands is infinity or NaN, do not do constant folding
 598   if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
 599     return TypeF::make( t1->getf() - t2->getf() );
 600   }
 601   else if( g_isnan(t1->getf()) ) {
 602     return t1;
 603   }
 604   else if( g_isnan(t2->getf()) ) {
 605     return t2;
 606   }
 607   else {
 608     return Type::FLOAT;
 609   }
 610 }
 611 
 612 //=============================================================================
 613 //------------------------------Ideal------------------------------------------
 614 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 615   const Type *t2 = phase->type( in(2) );
 616   // Convert "x-c0" into "x+ -c0".
 617   if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
 618     // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
 619   }
 620 
 621   // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
 622   // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
 623   //if( phase->type(in(1)) == TypeD::ZERO )
 624   //return new (phase->C, 2) NegDNode(in(2));
 625 
 626   return nullptr;
 627 }
 628 
 629 //------------------------------sub--------------------------------------------
 630 // A subtract node differences its two inputs.
 631 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
 632   // no folding if one of operands is infinity or NaN, do not do constant folding
 633   if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
 634     return TypeD::make( t1->getd() - t2->getd() );
 635   }
 636   else if( g_isnan(t1->getd()) ) {
 637     return t1;
 638   }
 639   else if( g_isnan(t2->getd()) ) {
 640     return t2;
 641   }
 642   else {
 643     return Type::DOUBLE;
 644   }
 645 }
 646 
 647 //=============================================================================
 648 //------------------------------Idealize---------------------------------------
 649 // Unlike SubNodes, compare must still flatten return value to the
 650 // range -1, 0, 1.
 651 // And optimizations like those for (X + Y) - X fail if overflow happens.
 652 Node* CmpNode::Identity(PhaseGVN* phase) {
 653   return this;
 654 }
 655 
 656 CmpNode *CmpNode::make(Node *in1, Node *in2, BasicType bt, bool unsigned_comp) {
 657   switch (bt) {
 658     case T_INT:
 659       if (unsigned_comp) {
 660         return new CmpUNode(in1, in2);
 661       }
 662       return new CmpINode(in1, in2);
 663     case T_LONG:
 664       if (unsigned_comp) {
 665         return new CmpULNode(in1, in2);
 666       }
 667       return new CmpLNode(in1, in2);
 668     case T_OBJECT:
 669     case T_ARRAY:
 670     case T_ADDRESS:
 671     case T_METADATA:
 672       return new CmpPNode(in1, in2);
 673     case T_NARROWOOP:
 674     case T_NARROWKLASS:
 675       return new CmpNNode(in1, in2);
 676     default:
 677       fatal("Not implemented for %s", type2name(bt));
 678   }
 679   return nullptr;
 680 }
 681 
 682 //=============================================================================
 683 //------------------------------cmp--------------------------------------------
 684 // Simplify a CmpI (compare 2 integers) node, based on local information.
 685 // If both inputs are constants, compare them.
 686 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 687   const TypeInt *r0 = t1->is_int(); // Handy access
 688   const TypeInt *r1 = t2->is_int();
 689 
 690   if( r0->_hi < r1->_lo )       // Range is always low?
 691     return TypeInt::CC_LT;
 692   else if( r0->_lo > r1->_hi )  // Range is always high?
 693     return TypeInt::CC_GT;
 694 
 695   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 696     assert(r0->get_con() == r1->get_con(), "must be equal");
 697     return TypeInt::CC_EQ;      // Equal results.
 698   } else if( r0->_hi == r1->_lo ) // Range is never high?
 699     return TypeInt::CC_LE;
 700   else if( r0->_lo == r1->_hi ) // Range is never low?
 701     return TypeInt::CC_GE;
 702   return TypeInt::CC;           // else use worst case results
 703 }
 704 
 705 const Type* CmpINode::Value(PhaseGVN* phase) const {
 706   Node* in1 = in(1);
 707   Node* in2 = in(2);
 708   // If this test is the zero trip guard for a main or post loop, check whether, with the opaque node removed, the test
 709   // would constant fold so the loop is never entered. If so return the type of the test without the opaque node removed:
 710   // make the loop unreachable.
 711   // The reason for this is that the iv phi captures the bounds of the loop and if the loop becomes unreachable, it can
 712   // become top. In that case, the loop must be removed.
 713   // This is safe because:
 714   // - as optimizations proceed, the range of iterations executed by the main loop narrows. If no iterations remain, then
 715   // we're done with optimizations for that loop.
 716   // - the post loop is initially not reachable but as long as there's a main loop, the zero trip guard for the post
 717   // loop takes a phi that merges the pre and main loop's iv and can't constant fold the zero trip guard. Once, the main
 718   // loop is removed, there's no need to preserve the zero trip guard for the post loop anymore.
 719   if (in1 != nullptr && in2 != nullptr) {
 720     uint input = 0;
 721     Node* cmp = nullptr;
 722     BoolTest::mask test;
 723     if (in1->Opcode() == Op_OpaqueZeroTripGuard && phase->type(in1) != Type::TOP) {
 724       cmp = new CmpINode(in1->in(1), in2);
 725       test = ((OpaqueZeroTripGuardNode*)in1)->_loop_entered_mask;
 726     }
 727     if (in2->Opcode() == Op_OpaqueZeroTripGuard && phase->type(in2) != Type::TOP) {
 728       assert(cmp == nullptr, "A cmp with 2 OpaqueZeroTripGuard inputs");
 729       cmp = new CmpINode(in1, in2->in(1));
 730       test = ((OpaqueZeroTripGuardNode*)in2)->_loop_entered_mask;
 731     }
 732     if (cmp != nullptr) {
 733       const Type* cmp_t = cmp->Value(phase);
 734       const Type* t = BoolTest(test).cc2logical(cmp_t);
 735       cmp->destruct(phase);
 736       if (t == TypeInt::ZERO) {
 737         return cmp_t;
 738       }
 739     }
 740   }
 741 
 742   return SubNode::Value(phase);
 743 }
 744 
 745 
 746 // Simplify a CmpU (compare 2 integers) node, based on local information.
 747 // If both inputs are constants, compare them.
 748 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 749   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 750 
 751   // comparing two unsigned ints
 752   const TypeInt *r0 = t1->is_int();   // Handy access
 753   const TypeInt *r1 = t2->is_int();
 754 
 755   // Current installed version
 756   // Compare ranges for non-overlap
 757   juint lo0 = r0->_lo;
 758   juint hi0 = r0->_hi;
 759   juint lo1 = r1->_lo;
 760   juint hi1 = r1->_hi;
 761 
 762   // If either one has both negative and positive values,
 763   // it therefore contains both 0 and -1, and since [0..-1] is the
 764   // full unsigned range, the type must act as an unsigned bottom.
 765   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 766   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 767 
 768   if (bot0 || bot1) {
 769     // All unsigned values are LE -1 and GE 0.
 770     if (lo0 == 0 && hi0 == 0) {
 771       return TypeInt::CC_LE;            //   0 <= bot
 772     } else if ((jint)lo0 == -1 && (jint)hi0 == -1) {
 773       return TypeInt::CC_GE;            // -1 >= bot
 774     } else if (lo1 == 0 && hi1 == 0) {
 775       return TypeInt::CC_GE;            // bot >= 0
 776     } else if ((jint)lo1 == -1 && (jint)hi1 == -1) {
 777       return TypeInt::CC_LE;            // bot <= -1
 778     }
 779   } else {
 780     // We can use ranges of the form [lo..hi] if signs are the same.
 781     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 782     // results are reversed, '-' > '+' for unsigned compare
 783     if (hi0 < lo1) {
 784       return TypeInt::CC_LT;            // smaller
 785     } else if (lo0 > hi1) {
 786       return TypeInt::CC_GT;            // greater
 787     } else if (hi0 == lo1 && lo0 == hi1) {
 788       return TypeInt::CC_EQ;            // Equal results
 789     } else if (lo0 >= hi1) {
 790       return TypeInt::CC_GE;
 791     } else if (hi0 <= lo1) {
 792       // Check for special case in Hashtable::get.  (See below.)
 793       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 794         return TypeInt::CC_LT;
 795       return TypeInt::CC_LE;
 796     }
 797   }
 798   // Check for special case in Hashtable::get - the hash index is
 799   // mod'ed to the table size so the following range check is useless.
 800   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 801   // to be positive.
 802   // (This is a gross hack, since the sub method never
 803   // looks at the structure of the node in any other case.)
 804   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 805     return TypeInt::CC_LT;
 806   return TypeInt::CC;                   // else use worst case results
 807 }
 808 
 809 const Type* CmpUNode::Value(PhaseGVN* phase) const {
 810   const Type* t = SubNode::Value_common(phase);
 811   if (t != nullptr) {
 812     return t;
 813   }
 814   const Node* in1 = in(1);
 815   const Node* in2 = in(2);
 816   const Type* t1 = phase->type(in1);
 817   const Type* t2 = phase->type(in2);
 818   assert(t1->isa_int(), "CmpU has only Int type inputs");
 819   if (t2 == TypeInt::INT) { // Compare to bottom?
 820     return bottom_type();
 821   }
 822 
 823   const Type* t_sub = sub(t1, t2); // compare based on immediate inputs
 824 
 825   uint in1_op = in1->Opcode();
 826   if (in1_op == Op_AddI || in1_op == Op_SubI) {
 827     // The problem rise when result of AddI(SubI) may overflow
 828     // signed integer value. Let say the input type is
 829     // [256, maxint] then +128 will create 2 ranges due to
 830     // overflow: [minint, minint+127] and [384, maxint].
 831     // But C2 type system keep only 1 type range and as result
 832     // it use general [minint, maxint] for this case which we
 833     // can't optimize.
 834     //
 835     // Make 2 separate type ranges based on types of AddI(SubI) inputs
 836     // and compare results of their compare. If results are the same
 837     // CmpU node can be optimized.
 838     const Node* in11 = in1->in(1);
 839     const Node* in12 = in1->in(2);
 840     const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11);
 841     const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12);
 842     // Skip cases when input types are top or bottom.
 843     if ((t11 != Type::TOP) && (t11 != TypeInt::INT) &&
 844         (t12 != Type::TOP) && (t12 != TypeInt::INT)) {
 845       const TypeInt *r0 = t11->is_int();
 846       const TypeInt *r1 = t12->is_int();
 847       jlong lo_r0 = r0->_lo;
 848       jlong hi_r0 = r0->_hi;
 849       jlong lo_r1 = r1->_lo;
 850       jlong hi_r1 = r1->_hi;
 851       if (in1_op == Op_SubI) {
 852         jlong tmp = hi_r1;
 853         hi_r1 = -lo_r1;
 854         lo_r1 = -tmp;
 855         // Note, for substructing [minint,x] type range
 856         // long arithmetic provides correct overflow answer.
 857         // The confusion come from the fact that in 32-bit
 858         // -minint == minint but in 64-bit -minint == maxint+1.
 859       }
 860       jlong lo_long = lo_r0 + lo_r1;
 861       jlong hi_long = hi_r0 + hi_r1;
 862       int lo_tr1 = min_jint;
 863       int hi_tr1 = (int)hi_long;
 864       int lo_tr2 = (int)lo_long;
 865       int hi_tr2 = max_jint;
 866       bool underflow = lo_long != (jlong)lo_tr2;
 867       bool overflow  = hi_long != (jlong)hi_tr1;
 868       // Use sub(t1, t2) when there is no overflow (one type range)
 869       // or when both overflow and underflow (too complex).
 870       if ((underflow != overflow) && (hi_tr1 < lo_tr2)) {
 871         // Overflow only on one boundary, compare 2 separate type ranges.
 872         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
 873         const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w);
 874         const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w);
 875         const TypeInt* cmp1 = sub(tr1, t2)->is_int();
 876         const TypeInt* cmp2 = sub(tr2, t2)->is_int();
 877         // Compute union, so that cmp handles all possible results from the two cases
 878         const Type* t_cmp = cmp1->meet(cmp2);
 879         // Pick narrowest type, based on overflow computation and on immediate inputs
 880         return t_sub->filter(t_cmp);
 881       }
 882     }
 883   }
 884 
 885   return t_sub;
 886 }
 887 
 888 bool CmpUNode::is_index_range_check() const {
 889   // Check for the "(X ModI Y) CmpU Y" shape
 890   return (in(1)->Opcode() == Op_ModI &&
 891           in(1)->in(2)->eqv_uncast(in(2)));
 892 }
 893 
 894 //------------------------------Idealize---------------------------------------
 895 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 896   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 897     switch (in(1)->Opcode()) {
 898     case Op_CmpU3:              // Collapse a CmpU3/CmpI into a CmpU
 899       return new CmpUNode(in(1)->in(1),in(1)->in(2));
 900     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 901       return new CmpLNode(in(1)->in(1),in(1)->in(2));
 902     case Op_CmpUL3:             // Collapse a CmpUL3/CmpI into a CmpUL
 903       return new CmpULNode(in(1)->in(1),in(1)->in(2));
 904     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 905       return new CmpFNode(in(1)->in(1),in(1)->in(2));
 906     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 907       return new CmpDNode(in(1)->in(1),in(1)->in(2));
 908     //case Op_SubI:
 909       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 910       // can be turned into (x <?> y).
 911       // This is handled (with more general cases) by Ideal_sub_algebra.
 912     }
 913   }
 914   return nullptr;                  // No change
 915 }
 916 
 917 Node *CmpLNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 918   const TypeLong *t2 = phase->type(in(2))->isa_long();
 919   if (Opcode() == Op_CmpL && in(1)->Opcode() == Op_ConvI2L && t2 && t2->is_con()) {
 920     const jlong con = t2->get_con();
 921     if (con >= min_jint && con <= max_jint) {
 922       return new CmpINode(in(1)->in(1), phase->intcon((jint)con));
 923     }
 924   }
 925   return nullptr;
 926 }
 927 
 928 //=============================================================================
 929 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 930 // If both inputs are constants, compare them.
 931 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 932   const TypeLong *r0 = t1->is_long(); // Handy access
 933   const TypeLong *r1 = t2->is_long();
 934 
 935   if( r0->_hi < r1->_lo )       // Range is always low?
 936     return TypeInt::CC_LT;
 937   else if( r0->_lo > r1->_hi )  // Range is always high?
 938     return TypeInt::CC_GT;
 939 
 940   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 941     assert(r0->get_con() == r1->get_con(), "must be equal");
 942     return TypeInt::CC_EQ;      // Equal results.
 943   } else if( r0->_hi == r1->_lo ) // Range is never high?
 944     return TypeInt::CC_LE;
 945   else if( r0->_lo == r1->_hi ) // Range is never low?
 946     return TypeInt::CC_GE;
 947   return TypeInt::CC;           // else use worst case results
 948 }
 949 
 950 
 951 // Simplify a CmpUL (compare 2 unsigned longs) node, based on local information.
 952 // If both inputs are constants, compare them.
 953 const Type* CmpULNode::sub(const Type* t1, const Type* t2) const {
 954   assert(!t1->isa_ptr(), "obsolete usage of CmpUL");
 955 
 956   // comparing two unsigned longs
 957   const TypeLong* r0 = t1->is_long();   // Handy access
 958   const TypeLong* r1 = t2->is_long();
 959 
 960   // Current installed version
 961   // Compare ranges for non-overlap
 962   julong lo0 = r0->_lo;
 963   julong hi0 = r0->_hi;
 964   julong lo1 = r1->_lo;
 965   julong hi1 = r1->_hi;
 966 
 967   // If either one has both negative and positive values,
 968   // it therefore contains both 0 and -1, and since [0..-1] is the
 969   // full unsigned range, the type must act as an unsigned bottom.
 970   bool bot0 = ((jlong)(lo0 ^ hi0) < 0);
 971   bool bot1 = ((jlong)(lo1 ^ hi1) < 0);
 972 
 973   if (bot0 || bot1) {
 974     // All unsigned values are LE -1 and GE 0.
 975     if (lo0 == 0 && hi0 == 0) {
 976       return TypeInt::CC_LE;            //   0 <= bot
 977     } else if ((jlong)lo0 == -1 && (jlong)hi0 == -1) {
 978       return TypeInt::CC_GE;            // -1 >= bot
 979     } else if (lo1 == 0 && hi1 == 0) {
 980       return TypeInt::CC_GE;            // bot >= 0
 981     } else if ((jlong)lo1 == -1 && (jlong)hi1 == -1) {
 982       return TypeInt::CC_LE;            // bot <= -1
 983     }
 984   } else {
 985     // We can use ranges of the form [lo..hi] if signs are the same.
 986     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 987     // results are reversed, '-' > '+' for unsigned compare
 988     if (hi0 < lo1) {
 989       return TypeInt::CC_LT;            // smaller
 990     } else if (lo0 > hi1) {
 991       return TypeInt::CC_GT;            // greater
 992     } else if (hi0 == lo1 && lo0 == hi1) {
 993       return TypeInt::CC_EQ;            // Equal results
 994     } else if (lo0 >= hi1) {
 995       return TypeInt::CC_GE;
 996     } else if (hi0 <= lo1) {
 997       return TypeInt::CC_LE;
 998     }
 999   }
1000 
1001   return TypeInt::CC;                   // else use worst case results
1002 }
1003 
1004 //=============================================================================
1005 //------------------------------sub--------------------------------------------
1006 // Simplify an CmpP (compare 2 pointers) node, based on local information.
1007 // If both inputs are constants, compare them.
1008 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
1009   const TypePtr *r0 = t1->is_ptr(); // Handy access
1010   const TypePtr *r1 = t2->is_ptr();
1011 
1012   // Undefined inputs makes for an undefined result
1013   if( TypePtr::above_centerline(r0->_ptr) ||
1014       TypePtr::above_centerline(r1->_ptr) )
1015     return Type::TOP;
1016 
1017   if (r0 == r1 && r0->singleton()) {
1018     // Equal pointer constants (klasses, nulls, etc.)
1019     return TypeInt::CC_EQ;
1020   }
1021 
1022   // See if it is 2 unrelated classes.
1023   const TypeOopPtr* p0 = r0->isa_oopptr();
1024   const TypeOopPtr* p1 = r1->isa_oopptr();
1025   const TypeKlassPtr* k0 = r0->isa_klassptr();
1026   const TypeKlassPtr* k1 = r1->isa_klassptr();
1027   if ((p0 && p1) || (k0 && k1)) {
1028     if (p0 && p1) {
1029       Node* in1 = in(1)->uncast();
1030       Node* in2 = in(2)->uncast();
1031       AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1);
1032       AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2);
1033       if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, nullptr)) {
1034         return TypeInt::CC_GT;  // different pointers
1035       }
1036     }
1037     bool    xklass0 = p0 ? p0->klass_is_exact() : k0->klass_is_exact();
1038     bool    xklass1 = p1 ? p1->klass_is_exact() : k1->klass_is_exact();
1039     bool unrelated_classes = false;
1040 
1041     if ((p0 && p0->is_same_java_type_as(p1)) ||
1042         (k0 && k0->is_same_java_type_as(k1))) {
1043     } else if ((p0 && !p1->maybe_java_subtype_of(p0) && !p0->maybe_java_subtype_of(p1)) ||
1044                (k0 && !k1->maybe_java_subtype_of(k0) && !k0->maybe_java_subtype_of(k1))) {
1045       unrelated_classes = true;
1046     } else if ((p0 && !p1->maybe_java_subtype_of(p0)) ||
1047                (k0 && !k1->maybe_java_subtype_of(k0))) {
1048       unrelated_classes = xklass1;
1049     } else if ((p0 && !p0->maybe_java_subtype_of(p1)) ||
1050                (k0 && !k0->maybe_java_subtype_of(k1))) {
1051       unrelated_classes = xklass0;
1052     }
1053 
1054     if (unrelated_classes) {
1055       // The oops classes are known to be unrelated. If the joined PTRs of
1056       // two oops is not Null and not Bottom, then we are sure that one
1057       // of the two oops is non-null, and the comparison will always fail.
1058       TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
1059       if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
1060         return TypeInt::CC_GT;
1061       }
1062     }
1063   }
1064 
1065   // Known constants can be compared exactly
1066   // Null can be distinguished from any NotNull pointers
1067   // Unknown inputs makes an unknown result
1068   if( r0->singleton() ) {
1069     intptr_t bits0 = r0->get_con();
1070     if( r1->singleton() )
1071       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1072     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1073   } else if( r1->singleton() ) {
1074     intptr_t bits1 = r1->get_con();
1075     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1076   } else
1077     return TypeInt::CC;
1078 }
1079 
1080 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
1081   // Return the klass node for (indirect load from OopHandle)
1082   //   LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
1083   //   or null if not matching.
1084   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1085     n = bs->step_over_gc_barrier(n);
1086 
1087   if (n->Opcode() != Op_LoadP) return nullptr;
1088 
1089   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
1090   if (!tp || tp->instance_klass() != phase->C->env()->Class_klass()) return nullptr;
1091 
1092   Node* adr = n->in(MemNode::Address);
1093   // First load from OopHandle: ((OopHandle)mirror)->resolve(); may need barrier.
1094   if (adr->Opcode() != Op_LoadP || !phase->type(adr)->isa_rawptr()) return nullptr;
1095   adr = adr->in(MemNode::Address);
1096 
1097   intptr_t off = 0;
1098   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
1099   if (k == nullptr)  return nullptr;
1100   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
1101   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return nullptr;
1102 
1103   // We've found the klass node of a Java mirror load.
1104   return k;
1105 }
1106 
1107 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
1108   // for ConP(Foo.class) return ConP(Foo.klass)
1109   // otherwise return null
1110   if (!n->is_Con()) return nullptr;
1111 
1112   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
1113   if (!tp) return nullptr;
1114 
1115   ciType* mirror_type = tp->java_mirror_type();
1116   // TypeInstPtr::java_mirror_type() returns non-null for compile-
1117   // time Class constants only.
1118   if (!mirror_type) return nullptr;
1119 
1120   // x.getClass() == int.class can never be true (for all primitive types)
1121   // Return a ConP(null) node for this case.
1122   if (mirror_type->is_classless()) {
1123     return phase->makecon(TypePtr::NULL_PTR);
1124   }
1125 
1126   // return the ConP(Foo.klass)
1127   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
1128   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass(), Type::trust_interfaces));
1129 }
1130 
1131 //------------------------------Ideal------------------------------------------
1132 // Normalize comparisons between Java mirror loads to compare the klass instead.
1133 //
1134 // Also check for the case of comparing an unknown klass loaded from the primary
1135 // super-type array vs a known klass with no subtypes.  This amounts to
1136 // checking to see an unknown klass subtypes a known klass with no subtypes;
1137 // this only happens on an exact match.  We can shorten this test by 1 load.
1138 Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1139   // Normalize comparisons between Java mirrors into comparisons of the low-
1140   // level klass, where a dependent load could be shortened.
1141   //
1142   // The new pattern has a nice effect of matching the same pattern used in the
1143   // fast path of instanceof/checkcast/Class.isInstance(), which allows
1144   // redundant exact type check be optimized away by GVN.
1145   // For example, in
1146   //   if (x.getClass() == Foo.class) {
1147   //     Foo foo = (Foo) x;
1148   //     // ... use a ...
1149   //   }
1150   // a CmpPNode could be shared between if_acmpne and checkcast
1151   {
1152     Node* k1 = isa_java_mirror_load(phase, in(1));
1153     Node* k2 = isa_java_mirror_load(phase, in(2));
1154     Node* conk2 = isa_const_java_mirror(phase, in(2));
1155 
1156     if (k1 && (k2 || conk2)) {
1157       Node* lhs = k1;
1158       Node* rhs = (k2 != nullptr) ? k2 : conk2;
1159       set_req_X(1, lhs, phase);
1160       set_req_X(2, rhs, phase);
1161       return this;
1162     }
1163   }
1164 
1165   // Constant pointer on right?
1166   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
1167   if (t2 == nullptr || !t2->klass_is_exact())
1168     return nullptr;
1169   // Get the constant klass we are comparing to.
1170   ciKlass* superklass = t2->exact_klass();
1171 
1172   // Now check for LoadKlass on left.
1173   Node* ldk1 = in(1);
1174   if (ldk1->is_DecodeNKlass()) {
1175     ldk1 = ldk1->in(1);
1176     if (ldk1->Opcode() != Op_LoadNKlass )
1177       return nullptr;
1178   } else if (ldk1->Opcode() != Op_LoadKlass )
1179     return nullptr;
1180   // Take apart the address of the LoadKlass:
1181   Node* adr1 = ldk1->in(MemNode::Address);
1182   intptr_t con2 = 0;
1183   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
1184   if (ldk2 == nullptr)
1185     return nullptr;
1186   if (con2 == Type::klass_offset()) {
1187     // We are inspecting an object's concrete class.
1188     // Short-circuit the check if the query is abstract.
1189     if (superklass->is_interface() ||
1190         superklass->is_abstract()) {
1191       // Make it come out always false:
1192       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
1193       return this;
1194     }
1195   }
1196 
1197   // Check for a LoadKlass from primary supertype array.
1198   // Any nested loadklass from loadklass+con must be from the p.s. array.
1199   if (ldk2->is_DecodeNKlass()) {
1200     // Keep ldk2 as DecodeN since it could be used in CmpP below.
1201     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
1202       return nullptr;
1203   } else if (ldk2->Opcode() != Op_LoadKlass)
1204     return nullptr;
1205 
1206   // Verify that we understand the situation
1207   if (con2 != (intptr_t) superklass->super_check_offset())
1208     return nullptr;                // Might be element-klass loading from array klass
1209 
1210   // If 'superklass' has no subklasses and is not an interface, then we are
1211   // assured that the only input which will pass the type check is
1212   // 'superklass' itself.
1213   //
1214   // We could be more liberal here, and allow the optimization on interfaces
1215   // which have a single implementor.  This would require us to increase the
1216   // expressiveness of the add_dependency() mechanism.
1217   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
1218 
1219   // Object arrays must have their base element have no subtypes
1220   while (superklass->is_obj_array_klass()) {
1221     ciType* elem = superklass->as_obj_array_klass()->element_type();
1222     superklass = elem->as_klass();
1223   }
1224   if (superklass->is_instance_klass()) {
1225     ciInstanceKlass* ik = superklass->as_instance_klass();
1226     if (ik->has_subklass() || ik->is_interface())  return nullptr;
1227     // Add a dependency if there is a chance that a subclass will be added later.
1228     if (!ik->is_final()) {
1229       phase->C->dependencies()->assert_leaf_type(ik);
1230     }
1231   }
1232 
1233   // Bypass the dependent load, and compare directly
1234   this->set_req_X(1, ldk2, phase);
1235 
1236   return this;
1237 }
1238 
1239 //=============================================================================
1240 //------------------------------sub--------------------------------------------
1241 // Simplify an CmpN (compare 2 pointers) node, based on local information.
1242 // If both inputs are constants, compare them.
1243 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
1244   ShouldNotReachHere();
1245   return bottom_type();
1246 }
1247 
1248 //------------------------------Ideal------------------------------------------
1249 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1250   return nullptr;
1251 }
1252 
1253 //=============================================================================
1254 //------------------------------Value------------------------------------------
1255 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1256 // If both inputs are constants, compare them.
1257 const Type* CmpFNode::Value(PhaseGVN* phase) const {
1258   const Node* in1 = in(1);
1259   const Node* in2 = in(2);
1260   // Either input is TOP ==> the result is TOP
1261   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1262   if( t1 == Type::TOP ) return Type::TOP;
1263   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1264   if( t2 == Type::TOP ) return Type::TOP;
1265 
1266   // Not constants?  Don't know squat - even if they are the same
1267   // value!  If they are NaN's they compare to LT instead of EQ.
1268   const TypeF *tf1 = t1->isa_float_constant();
1269   const TypeF *tf2 = t2->isa_float_constant();
1270   if( !tf1 || !tf2 ) return TypeInt::CC;
1271 
1272   // This implements the Java bytecode fcmpl, so unordered returns -1.
1273   if( tf1->is_nan() || tf2->is_nan() )
1274     return TypeInt::CC_LT;
1275 
1276   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
1277   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
1278   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
1279   return TypeInt::CC_EQ;
1280 }
1281 
1282 
1283 //=============================================================================
1284 //------------------------------Value------------------------------------------
1285 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
1286 // If both inputs are constants, compare them.
1287 const Type* CmpDNode::Value(PhaseGVN* phase) const {
1288   const Node* in1 = in(1);
1289   const Node* in2 = in(2);
1290   // Either input is TOP ==> the result is TOP
1291   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1292   if( t1 == Type::TOP ) return Type::TOP;
1293   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1294   if( t2 == Type::TOP ) return Type::TOP;
1295 
1296   // Not constants?  Don't know squat - even if they are the same
1297   // value!  If they are NaN's they compare to LT instead of EQ.
1298   const TypeD *td1 = t1->isa_double_constant();
1299   const TypeD *td2 = t2->isa_double_constant();
1300   if( !td1 || !td2 ) return TypeInt::CC;
1301 
1302   // This implements the Java bytecode dcmpl, so unordered returns -1.
1303   if( td1->is_nan() || td2->is_nan() )
1304     return TypeInt::CC_LT;
1305 
1306   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
1307   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
1308   assert( td1->_d == td2->_d, "do not understand FP behavior" );
1309   return TypeInt::CC_EQ;
1310 }
1311 
1312 //------------------------------Ideal------------------------------------------
1313 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
1314   // Check if we can change this to a CmpF and remove a ConvD2F operation.
1315   // Change  (CMPD (F2D (float)) (ConD value))
1316   // To      (CMPF      (float)  (ConF value))
1317   // Valid when 'value' does not lose precision as a float.
1318   // Benefits: eliminates conversion, does not require 24-bit mode
1319 
1320   // NaNs prevent commuting operands.  This transform works regardless of the
1321   // order of ConD and ConvF2D inputs by preserving the original order.
1322   int idx_f2d = 1;              // ConvF2D on left side?
1323   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1324     idx_f2d = 2;                // No, swap to check for reversed args
1325   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1326 
1327   if( ConvertCmpD2CmpF &&
1328       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1329       in(idx_con)->Opcode() == Op_ConD ) {
1330     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1331     double t2_value_as_double = t2->_d;
1332     float  t2_value_as_float  = (float)t2_value_as_double;
1333     if( t2_value_as_double == (double)t2_value_as_float ) {
1334       // Test value can be represented as a float
1335       // Eliminate the conversion to double and create new comparison
1336       Node *new_in1 = in(idx_f2d)->in(1);
1337       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1338       if( idx_f2d != 1 ) {      // Must flip args to match original order
1339         Node *tmp = new_in1;
1340         new_in1 = new_in2;
1341         new_in2 = tmp;
1342       }
1343       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1344         ? new CmpF3Node( new_in1, new_in2 )
1345         : new CmpFNode ( new_in1, new_in2 ) ;
1346       return new_cmp;           // Changed to CmpFNode
1347     }
1348     // Testing value required the precision of a double
1349   }
1350   return nullptr;                  // No change
1351 }
1352 
1353 
1354 //=============================================================================
1355 //------------------------------cc2logical-------------------------------------
1356 // Convert a condition code type to a logical type
1357 const Type *BoolTest::cc2logical( const Type *CC ) const {
1358   if( CC == Type::TOP ) return Type::TOP;
1359   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1360   const TypeInt *ti = CC->is_int();
1361   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1362     // Match low order 2 bits
1363     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1364     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1365     return TypeInt::make(tmp);       // Boolean result
1366   }
1367 
1368   if( CC == TypeInt::CC_GE ) {
1369     if( _test == ge ) return TypeInt::ONE;
1370     if( _test == lt ) return TypeInt::ZERO;
1371   }
1372   if( CC == TypeInt::CC_LE ) {
1373     if( _test == le ) return TypeInt::ONE;
1374     if( _test == gt ) return TypeInt::ZERO;
1375   }
1376 
1377   return TypeInt::BOOL;
1378 }
1379 
1380 //------------------------------dump_spec-------------------------------------
1381 // Print special per-node info
1382 void BoolTest::dump_on(outputStream *st) const {
1383   const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
1384   st->print("%s", msg[_test]);
1385 }
1386 
1387 // Returns the logical AND of two tests (or 'never' if both tests can never be true).
1388 // For example, a test for 'le' followed by a test for 'lt' is equivalent with 'lt'.
1389 BoolTest::mask BoolTest::merge(BoolTest other) const {
1390   const mask res[illegal+1][illegal+1] = {
1391     // eq,      gt,      of,      lt,      ne,      le,      nof,     ge,      never,   illegal
1392       {eq,      never,   illegal, never,   never,   eq,      illegal, eq,      never,   illegal},  // eq
1393       {never,   gt,      illegal, never,   gt,      never,   illegal, gt,      never,   illegal},  // gt
1394       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // of
1395       {never,   never,   illegal, lt,      lt,      lt,      illegal, never,   never,   illegal},  // lt
1396       {never,   gt,      illegal, lt,      ne,      lt,      illegal, gt,      never,   illegal},  // ne
1397       {eq,      never,   illegal, lt,      lt,      le,      illegal, eq,      never,   illegal},  // le
1398       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // nof
1399       {eq,      gt,      illegal, never,   gt,      eq,      illegal, ge,      never,   illegal},  // ge
1400       {never,   never,   never,   never,   never,   never,   never,   never,   never,   illegal},  // never
1401       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal}}; // illegal
1402   return res[_test][other._test];
1403 }
1404 
1405 //=============================================================================
1406 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1407 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1408 
1409 //------------------------------operator==-------------------------------------
1410 bool BoolNode::cmp( const Node &n ) const {
1411   const BoolNode *b = (const BoolNode *)&n; // Cast up
1412   return (_test._test == b->_test._test);
1413 }
1414 
1415 //-------------------------------make_predicate--------------------------------
1416 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1417   if (test_value->is_Con())   return test_value;
1418   if (test_value->is_Bool())  return test_value;
1419   if (test_value->is_CMove() &&
1420       test_value->in(CMoveNode::Condition)->is_Bool()) {
1421     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1422     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1423     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1424     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1425       return bol;
1426     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1427       return phase->transform( bol->negate(phase) );
1428     }
1429     // Else fall through.  The CMove gets in the way of the test.
1430     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1431   }
1432   Node* cmp = new CmpINode(test_value, phase->intcon(0));
1433   cmp = phase->transform(cmp);
1434   Node* bol = new BoolNode(cmp, BoolTest::ne);
1435   return phase->transform(bol);
1436 }
1437 
1438 //--------------------------------as_int_value---------------------------------
1439 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1440   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1441   Node* cmov = CMoveNode::make(this, phase->intcon(0), phase->intcon(1), TypeInt::BOOL);
1442   return phase->transform(cmov);
1443 }
1444 
1445 //----------------------------------negate-------------------------------------
1446 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1447   return new BoolNode(in(1), _test.negate());
1448 }
1449 
1450 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub
1451 // overflows and we can prove that C is not in the two resulting ranges.
1452 // This optimization is similar to the one performed by CmpUNode::Value().
1453 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, int cmp_op,
1454                           int cmp1_op, const TypeInt* cmp2_type) {
1455   // Only optimize eq/ne integer comparison of add/sub
1456   if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1457      (cmp_op == Op_CmpI) && (cmp1_op == Op_AddI || cmp1_op == Op_SubI)) {
1458     // Skip cases were inputs of add/sub are not integers or of bottom type
1459     const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int();
1460     const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int();
1461     if ((r0 != nullptr) && (r0 != TypeInt::INT) &&
1462         (r1 != nullptr) && (r1 != TypeInt::INT) &&
1463         (cmp2_type != TypeInt::INT)) {
1464       // Compute exact (long) type range of add/sub result
1465       jlong lo_long = r0->_lo;
1466       jlong hi_long = r0->_hi;
1467       if (cmp1_op == Op_AddI) {
1468         lo_long += r1->_lo;
1469         hi_long += r1->_hi;
1470       } else {
1471         lo_long -= r1->_hi;
1472         hi_long -= r1->_lo;
1473       }
1474       // Check for over-/underflow by casting to integer
1475       int lo_int = (int)lo_long;
1476       int hi_int = (int)hi_long;
1477       bool underflow = lo_long != (jlong)lo_int;
1478       bool overflow  = hi_long != (jlong)hi_int;
1479       if ((underflow != overflow) && (hi_int < lo_int)) {
1480         // Overflow on one boundary, compute resulting type ranges:
1481         // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT]
1482         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
1483         const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w);
1484         const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w);
1485         // Compare second input of cmp to both type ranges
1486         const Type* sub_tr1 = cmp->sub(tr1, cmp2_type);
1487         const Type* sub_tr2 = cmp->sub(tr2, cmp2_type);
1488         if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) {
1489           // The result of the add/sub will never equal cmp2. Replace BoolNode
1490           // by false (0) if it tests for equality and by true (1) otherwise.
1491           return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1);
1492         }
1493       }
1494     }
1495   }
1496   return nullptr;
1497 }
1498 
1499 static bool is_counted_loop_cmp(Node *cmp) {
1500   Node *n = cmp->in(1)->in(1);
1501   return n != nullptr &&
1502          n->is_Phi() &&
1503          n->in(0) != nullptr &&
1504          n->in(0)->is_CountedLoop() &&
1505          n->in(0)->as_CountedLoop()->phi() == n;
1506 }
1507 
1508 //------------------------------Ideal------------------------------------------
1509 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1510   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1511   // This moves the constant to the right.  Helps value-numbering.
1512   Node *cmp = in(1);
1513   if( !cmp->is_Sub() ) return nullptr;
1514   int cop = cmp->Opcode();
1515   if( cop == Op_FastLock || cop == Op_FastUnlock ||
1516       cmp->is_SubTypeCheck() || cop == Op_VectorTest ) {
1517     return nullptr;
1518   }
1519   Node *cmp1 = cmp->in(1);
1520   Node *cmp2 = cmp->in(2);
1521   if( !cmp1 ) return nullptr;
1522 
1523   if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) {
1524     return nullptr;
1525   }
1526 
1527   const int cmp1_op = cmp1->Opcode();
1528   const int cmp2_op = cmp2->Opcode();
1529 
1530   // Constant on left?
1531   Node *con = cmp1;
1532   // Move constants to the right of compare's to canonicalize.
1533   // Do not muck with Opaque1 nodes, as this indicates a loop
1534   // guard that cannot change shape.
1535   if (con->is_Con() && !cmp2->is_Con() && cmp2_op != Op_OpaqueZeroTripGuard &&
1536       // Because of NaN's, CmpD and CmpF are not commutative
1537       cop != Op_CmpD && cop != Op_CmpF &&
1538       // Protect against swapping inputs to a compare when it is used by a
1539       // counted loop exit, which requires maintaining the loop-limit as in(2)
1540       !is_counted_loop_exit_test() ) {
1541     // Ok, commute the constant to the right of the cmp node.
1542     // Clone the Node, getting a new Node of the same class
1543     cmp = cmp->clone();
1544     // Swap inputs to the clone
1545     cmp->swap_edges(1, 2);
1546     cmp = phase->transform( cmp );
1547     return new BoolNode( cmp, _test.commute() );
1548   }
1549 
1550   // Change "bool eq/ne (cmp (cmove (bool tst (cmp2)) 1 0) 0)" into "bool tst/~tst (cmp2)"
1551   if (cop == Op_CmpI &&
1552       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1553       cmp1_op == Op_CMoveI && cmp2->find_int_con(1) == 0) {
1554     // 0 should be on the true branch
1555     if (cmp1->in(CMoveNode::Condition)->is_Bool() &&
1556         cmp1->in(CMoveNode::IfTrue)->find_int_con(1) == 0 &&
1557         cmp1->in(CMoveNode::IfFalse)->find_int_con(0) != 0) {
1558       BoolNode* target = cmp1->in(CMoveNode::Condition)->as_Bool();
1559       return new BoolNode(target->in(1),
1560                           (_test._test == BoolTest::eq) ? target->_test._test :
1561                                                           target->_test.negate());
1562     }
1563   }
1564 
1565   // Change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)".
1566   if (cop == Op_CmpI &&
1567       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1568       cmp1_op == Op_AndI && cmp2_op == Op_ConI &&
1569       cmp1->in(2)->Opcode() == Op_ConI) {
1570     const TypeInt *t12 = phase->type(cmp2)->isa_int();
1571     const TypeInt *t112 = phase->type(cmp1->in(2))->isa_int();
1572     if (t12 && t12->is_con() && t112 && t112->is_con() &&
1573         t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) {
1574       Node *ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1575       return new BoolNode(ncmp, _test.negate());
1576     }
1577   }
1578 
1579   // Same for long type: change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)".
1580   if (cop == Op_CmpL &&
1581       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1582       cmp1_op == Op_AndL && cmp2_op == Op_ConL &&
1583       cmp1->in(2)->Opcode() == Op_ConL) {
1584     const TypeLong *t12 = phase->type(cmp2)->isa_long();
1585     const TypeLong *t112 = phase->type(cmp1->in(2))->isa_long();
1586     if (t12 && t12->is_con() && t112 && t112->is_con() &&
1587         t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) {
1588       Node *ncmp = phase->transform(new CmpLNode(cmp1, phase->longcon(0)));
1589       return new BoolNode(ncmp, _test.negate());
1590     }
1591   }
1592 
1593   // Change "cmp (add X min_jint) (add Y min_jint)" into "cmpu X Y"
1594   // and    "cmp (add X min_jint) c" into "cmpu X (c + min_jint)"
1595   if (cop == Op_CmpI &&
1596       cmp1_op == Op_AddI &&
1597       phase->type(cmp1->in(2)) == TypeInt::MIN &&
1598       !is_cloop_condition(this)) {
1599     if (cmp2_op == Op_ConI) {
1600       Node* ncmp2 = phase->intcon(java_add(cmp2->get_int(), min_jint));
1601       Node* ncmp = phase->transform(new CmpUNode(cmp1->in(1), ncmp2));
1602       return new BoolNode(ncmp, _test._test);
1603     } else if (cmp2_op == Op_AddI &&
1604                phase->type(cmp2->in(2)) == TypeInt::MIN &&
1605                !is_cloop_condition(this)) {
1606       Node* ncmp = phase->transform(new CmpUNode(cmp1->in(1), cmp2->in(1)));
1607       return new BoolNode(ncmp, _test._test);
1608     }
1609   }
1610 
1611   // Change "cmp (add X min_jlong) (add Y min_jlong)" into "cmpu X Y"
1612   // and    "cmp (add X min_jlong) c" into "cmpu X (c + min_jlong)"
1613   if (cop == Op_CmpL &&
1614       cmp1_op == Op_AddL &&
1615       phase->type(cmp1->in(2)) == TypeLong::MIN &&
1616       !is_cloop_condition(this)) {
1617     if (cmp2_op == Op_ConL) {
1618       Node* ncmp2 = phase->longcon(java_add(cmp2->get_long(), min_jlong));
1619       Node* ncmp = phase->transform(new CmpULNode(cmp1->in(1), ncmp2));
1620       return new BoolNode(ncmp, _test._test);
1621     } else if (cmp2_op == Op_AddL &&
1622                phase->type(cmp2->in(2)) == TypeLong::MIN &&
1623                !is_cloop_condition(this)) {
1624       Node* ncmp = phase->transform(new CmpULNode(cmp1->in(1), cmp2->in(1)));
1625       return new BoolNode(ncmp, _test._test);
1626     }
1627   }
1628 
1629   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1630   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1631   // test instead.
1632   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1633   if (cmp2_type == nullptr)  return nullptr;
1634   Node* j_xor = cmp1;
1635   if( cmp2_type == TypeInt::ZERO &&
1636       cmp1_op == Op_XorI &&
1637       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1638       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1639       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1640       (_test._test == BoolTest::eq ||
1641        _test._test == BoolTest::ne) ) {
1642     Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2));
1643     return new BoolNode( ncmp, _test.negate() );
1644   }
1645 
1646   // Transform: "((x & (m - 1)) <u m)" or "(((m - 1) & x) <u m)" into "(m >u 0)"
1647   // This is case [CMPU_MASK] which is further described at the method comment of BoolNode::Value_cmpu_and_mask().
1648   if (cop == Op_CmpU && _test._test == BoolTest::lt && cmp1_op == Op_AndI) {
1649     Node* m = cmp2; // RHS: m
1650     for (int add_idx = 1; add_idx <= 2; add_idx++) { // LHS: "(m + (-1)) & x" or "x & (m + (-1))"?
1651       Node* maybe_m_minus_1 = cmp1->in(add_idx);
1652       if (maybe_m_minus_1->Opcode() == Op_AddI &&
1653           maybe_m_minus_1->in(2)->find_int_con(0) == -1 &&
1654           maybe_m_minus_1->in(1) == m) {
1655         Node* m_cmpu_0 = phase->transform(new CmpUNode(m, phase->intcon(0)));
1656         return new BoolNode(m_cmpu_0, BoolTest::gt);
1657       }
1658     }
1659   }
1660 
1661   // Change x u< 1 or x u<= 0 to x == 0
1662   // and    x u> 0 or u>= 1   to x != 0
1663   if (cop == Op_CmpU &&
1664       cmp1_op != Op_LoadRange &&
1665       (((_test._test == BoolTest::lt || _test._test == BoolTest::ge) &&
1666         cmp2->find_int_con(-1) == 1) ||
1667        ((_test._test == BoolTest::le || _test._test == BoolTest::gt) &&
1668         cmp2->find_int_con(-1) == 0))) {
1669     Node* ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1670     return new BoolNode(ncmp, _test.is_less() ? BoolTest::eq : BoolTest::ne);
1671   }
1672 
1673   // Change (arraylength <= 0) or (arraylength == 0)
1674   //   into (arraylength u<= 0)
1675   // Also change (arraylength != 0) into (arraylength u> 0)
1676   // The latter version matches the code pattern generated for
1677   // array range checks, which will more likely be optimized later.
1678   if (cop == Op_CmpI &&
1679       cmp1_op == Op_LoadRange &&
1680       cmp2->find_int_con(-1) == 0) {
1681     if (_test._test == BoolTest::le || _test._test == BoolTest::eq) {
1682       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1683       return new BoolNode(ncmp, BoolTest::le);
1684     } else if (_test._test == BoolTest::ne) {
1685       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1686       return new BoolNode(ncmp, BoolTest::gt);
1687     }
1688   }
1689 
1690   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1691   // This is a standard idiom for branching on a boolean value.
1692   Node *c2b = cmp1;
1693   if( cmp2_type == TypeInt::ZERO &&
1694       cmp1_op == Op_Conv2B &&
1695       (_test._test == BoolTest::eq ||
1696        _test._test == BoolTest::ne) ) {
1697     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1698        ? (Node*)new CmpINode(c2b->in(1),cmp2)
1699        : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1700     );
1701     return new BoolNode( ncmp, _test._test );
1702   }
1703 
1704   // Comparing a SubI against a zero is equal to comparing the SubI
1705   // arguments directly.  This only works for eq and ne comparisons
1706   // due to possible integer overflow.
1707   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1708         (cop == Op_CmpI) &&
1709         (cmp1_op == Op_SubI) &&
1710         ( cmp2_type == TypeInt::ZERO ) ) {
1711     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2)));
1712     return new BoolNode( ncmp, _test._test );
1713   }
1714 
1715   // Same as above but with and AddI of a constant
1716   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1717       cop == Op_CmpI &&
1718       cmp1_op == Op_AddI &&
1719       cmp1->in(2) != nullptr &&
1720       phase->type(cmp1->in(2))->isa_int() &&
1721       phase->type(cmp1->in(2))->is_int()->is_con() &&
1722       cmp2_type == TypeInt::ZERO &&
1723       !is_counted_loop_cmp(cmp) // modifying the exit test of a counted loop messes the counted loop shape
1724       ) {
1725     const TypeInt* cmp1_in2 = phase->type(cmp1->in(2))->is_int();
1726     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),phase->intcon(-cmp1_in2->_hi)));
1727     return new BoolNode( ncmp, _test._test );
1728   }
1729 
1730   // Change "bool eq/ne (cmp (phi (X -X) 0))" into "bool eq/ne (cmp X 0)"
1731   // since zero check of conditional negation of an integer is equal to
1732   // zero check of the integer directly.
1733   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1734       (cop == Op_CmpI) &&
1735       (cmp2_type == TypeInt::ZERO) &&
1736       (cmp1_op == Op_Phi)) {
1737     // There should be a diamond phi with true path at index 1 or 2
1738     PhiNode *phi = cmp1->as_Phi();
1739     int idx_true = phi->is_diamond_phi();
1740     if (idx_true != 0) {
1741       // True input is in(idx_true) while false input is in(3 - idx_true)
1742       Node *tin = phi->in(idx_true);
1743       Node *fin = phi->in(3 - idx_true);
1744       if ((tin->Opcode() == Op_SubI) &&
1745           (phase->type(tin->in(1)) == TypeInt::ZERO) &&
1746           (tin->in(2) == fin)) {
1747         // Found conditional negation at true path, create a new CmpINode without that
1748         Node *ncmp = phase->transform(new CmpINode(fin, cmp2));
1749         return new BoolNode(ncmp, _test._test);
1750       }
1751       if ((fin->Opcode() == Op_SubI) &&
1752           (phase->type(fin->in(1)) == TypeInt::ZERO) &&
1753           (fin->in(2) == tin)) {
1754         // Found conditional negation at false path, create a new CmpINode without that
1755         Node *ncmp = phase->transform(new CmpINode(tin, cmp2));
1756         return new BoolNode(ncmp, _test._test);
1757       }
1758     }
1759   }
1760 
1761   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1762   // most general case because negating 0x80000000 does nothing.  Needed for
1763   // the CmpF3/SubI/CmpI idiom.
1764   if( cop == Op_CmpI &&
1765       cmp1_op == Op_SubI &&
1766       cmp2_type == TypeInt::ZERO &&
1767       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1768       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1769     Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2));
1770     return new BoolNode( ncmp, _test.commute() );
1771   }
1772 
1773   // Try to optimize signed integer comparison
1774   return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type);
1775 
1776   //  The transformation below is not valid for either signed or unsigned
1777   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1778   //  This transformation can be resurrected when we are able to
1779   //  make inferences about the range of values being subtracted from
1780   //  (or added to) relative to the wraparound point.
1781   //
1782   //    // Remove +/-1's if possible.
1783   //    // "X <= Y-1" becomes "X <  Y"
1784   //    // "X+1 <= Y" becomes "X <  Y"
1785   //    // "X <  Y+1" becomes "X <= Y"
1786   //    // "X-1 <  Y" becomes "X <= Y"
1787   //    // Do not this to compares off of the counted-loop-end.  These guys are
1788   //    // checking the trip counter and they want to use the post-incremented
1789   //    // counter.  If they use the PRE-incremented counter, then the counter has
1790   //    // to be incremented in a private block on a loop backedge.
1791   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1792   //      return nullptr;
1793   //  #ifndef PRODUCT
1794   //    // Do not do this in a wash GVN pass during verification.
1795   //    // Gets triggered by too many simple optimizations to be bothered with
1796   //    // re-trying it again and again.
1797   //    if( !phase->allow_progress() ) return nullptr;
1798   //  #endif
1799   //    // Not valid for unsigned compare because of corner cases in involving zero.
1800   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1801   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1802   //    // "0 <=u Y" is always true).
1803   //    if( cmp->Opcode() == Op_CmpU ) return nullptr;
1804   //    int cmp2_op = cmp2->Opcode();
1805   //    if( _test._test == BoolTest::le ) {
1806   //      if( cmp1_op == Op_AddI &&
1807   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1808   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1809   //      else if( cmp2_op == Op_AddI &&
1810   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1811   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1812   //    } else if( _test._test == BoolTest::lt ) {
1813   //      if( cmp1_op == Op_AddI &&
1814   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1815   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1816   //      else if( cmp2_op == Op_AddI &&
1817   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1818   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1819   //    }
1820 }
1821 
1822 // We use the following Lemmas/insights for the following two transformations (1) and (2):
1823 //   x & y <=u y, for any x and y           (Lemma 1, masking always results in a smaller unsigned number)
1824 //   y <u y + 1 is always true if y != -1   (Lemma 2, (uint)(-1 + 1) == (uint)(UINT_MAX + 1) which overflows)
1825 //   y <u 0 is always false for any y       (Lemma 3, 0 == UINT_MIN and nothing can be smaller than that)
1826 //
1827 // (1a) Always:     Change ((x & m) <=u m  ) or ((m & x) <=u m  ) to always true   (true by Lemma 1)
1828 // (1b) If m != -1: Change ((x & m) <u  m + 1) or ((m & x) <u  m + 1) to always true:
1829 //    x & m <=u m          is always true   // (Lemma 1)
1830 //    x & m <=u m <u m + 1 is always true   // (Lemma 2: m <u m + 1, if m != -1)
1831 //
1832 // A counter example for (1b), if we allowed m == -1:
1833 //     (x & m)  <u m + 1
1834 //     (x & -1) <u 0
1835 //      x       <u 0
1836 //   which is false for any x (Lemma 3)
1837 //
1838 // (2) Change ((x & (m - 1)) <u m) or (((m - 1) & x) <u m) to (m >u 0)
1839 // This is the off-by-one variant of the above.
1840 //
1841 // We now prove that this replacement is correct. This is the same as proving
1842 //   "m >u 0" if and only if "x & (m - 1) <u m", i.e. "m >u 0 <=> x & (m - 1) <u m"
1843 //
1844 // We use (Lemma 1) and (Lemma 3) from above.
1845 //
1846 // Case "x & (m - 1) <u m => m >u 0":
1847 //   We prove this by contradiction:
1848 //     Assume m <=u 0 which is equivalent to m == 0:
1849 //   and thus
1850 //     x & (m - 1) <u m = 0               // m == 0
1851 //     y           <u     0               // y = x & (m - 1)
1852 //   by Lemma 3, this is always false, i.e. a contradiction to our assumption.
1853 //
1854 // Case "m >u 0 => x & (m - 1) <u m":
1855 //   x & (m - 1) <=u (m - 1)              // (Lemma 1)
1856 //   x & (m - 1) <=u (m - 1) <u m         // Using assumption m >u 0, no underflow of "m - 1"
1857 //
1858 //
1859 // Note that the signed version of "m > 0":
1860 //   m > 0 <=> x & (m - 1) <u m
1861 // does not hold:
1862 //   Assume m == -1 and x == -1:
1863 //     x  & (m - 1) <u m
1864 //     -1 & -2      <u -1
1865 //     -2           <u -1
1866 //     UINT_MAX - 1 <u UINT_MAX           // Signed to unsigned numbers
1867 // which is true while
1868 //   m > 0
1869 // is false which is a contradiction.
1870 //
1871 // (1a) and (1b) is covered by this method since we can directly return a true value as type while (2) is covered
1872 // in BoolNode::Ideal since we create a new non-constant node (see [CMPU_MASK]).
1873 const Type* BoolNode::Value_cmpu_and_mask(PhaseValues* phase) const {
1874   Node* cmp = in(1);
1875   if (cmp != nullptr && cmp->Opcode() == Op_CmpU) {
1876     Node* cmp1 = cmp->in(1);
1877     Node* cmp2 = cmp->in(2);
1878 
1879     if (cmp1->Opcode() == Op_AndI) {
1880       Node* m = nullptr;
1881       if (_test._test == BoolTest::le) {
1882         // (1a) "((x & m) <=u m)", cmp2 = m
1883         m = cmp2;
1884       } else if (_test._test == BoolTest::lt && cmp2->Opcode() == Op_AddI && cmp2->in(2)->find_int_con(0) == 1) {
1885         // (1b) "(x & m) <u m + 1" and "(m & x) <u m + 1", cmp2 = m + 1
1886         Node* rhs_m = cmp2->in(1);
1887         const TypeInt* rhs_m_type = phase->type(rhs_m)->isa_int();
1888         if (rhs_m_type->_lo > -1 || rhs_m_type->_hi < -1) {
1889           // Exclude any case where m == -1 is possible.
1890           m = rhs_m;
1891         }
1892       }
1893 
1894       if (cmp1->in(2) == m || cmp1->in(1) == m) {
1895         return TypeInt::ONE;
1896       }
1897     }
1898   }
1899 
1900   return nullptr;
1901 }
1902 
1903 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
1904 // based on local information.   If the input is constant, do it.
1905 const Type* BoolNode::Value(PhaseGVN* phase) const {
1906   const Type* t = Value_cmpu_and_mask(phase);
1907   if (t != nullptr) {
1908     return t;
1909   }
1910 
1911   return _test.cc2logical( phase->type( in(1) ) );
1912 }
1913 
1914 #ifndef PRODUCT
1915 //------------------------------dump_spec--------------------------------------
1916 // Dump special per-node info
1917 void BoolNode::dump_spec(outputStream *st) const {
1918   st->print("[");
1919   _test.dump_on(st);
1920   st->print("]");
1921 }
1922 #endif
1923 
1924 //----------------------is_counted_loop_exit_test------------------------------
1925 // Returns true if node is used by a counted loop node.
1926 bool BoolNode::is_counted_loop_exit_test() {
1927   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
1928     Node* use = fast_out(i);
1929     if (use->is_CountedLoopEnd()) {
1930       return true;
1931     }
1932   }
1933   return false;
1934 }
1935 
1936 //=============================================================================
1937 //------------------------------Value------------------------------------------
1938 const Type* AbsNode::Value(PhaseGVN* phase) const {
1939   const Type* t1 = phase->type(in(1));
1940   if (t1 == Type::TOP) return Type::TOP;
1941 
1942   switch (t1->base()) {
1943   case Type::Int: {
1944     const TypeInt* ti = t1->is_int();
1945     if (ti->is_con()) {
1946       return TypeInt::make(uabs(ti->get_con()));
1947     }
1948     break;
1949   }
1950   case Type::Long: {
1951     const TypeLong* tl = t1->is_long();
1952     if (tl->is_con()) {
1953       return TypeLong::make(uabs(tl->get_con()));
1954     }
1955     break;
1956   }
1957   case Type::FloatCon:
1958     return TypeF::make(abs(t1->getf()));
1959   case Type::DoubleCon:
1960     return TypeD::make(abs(t1->getd()));
1961   default:
1962     break;
1963   }
1964 
1965   return bottom_type();
1966 }
1967 
1968 //------------------------------Identity----------------------------------------
1969 Node* AbsNode::Identity(PhaseGVN* phase) {
1970   Node* in1 = in(1);
1971   // No need to do abs for non-negative values
1972   if (phase->type(in1)->higher_equal(TypeInt::POS) ||
1973       phase->type(in1)->higher_equal(TypeLong::POS)) {
1974     return in1;
1975   }
1976   // Convert "abs(abs(x))" into "abs(x)"
1977   if (in1->Opcode() == Opcode()) {
1978     return in1;
1979   }
1980   return this;
1981 }
1982 
1983 //------------------------------Ideal------------------------------------------
1984 Node* AbsNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1985   Node* in1 = in(1);
1986   // Convert "abs(0-x)" into "abs(x)"
1987   if (in1->is_Sub() && phase->type(in1->in(1))->is_zero_type()) {
1988     set_req_X(1, in1->in(2), phase);
1989     return this;
1990   }
1991   return nullptr;
1992 }
1993 
1994 //=============================================================================
1995 //------------------------------Value------------------------------------------
1996 // Compute sqrt
1997 const Type* SqrtDNode::Value(PhaseGVN* phase) const {
1998   const Type *t1 = phase->type( in(1) );
1999   if( t1 == Type::TOP ) return Type::TOP;
2000   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
2001   double d = t1->getd();
2002   if( d < 0.0 ) return Type::DOUBLE;
2003   return TypeD::make( sqrt( d ) );
2004 }
2005 
2006 const Type* SqrtFNode::Value(PhaseGVN* phase) const {
2007   const Type *t1 = phase->type( in(1) );
2008   if( t1 == Type::TOP ) return Type::TOP;
2009   if( t1->base() != Type::FloatCon ) return Type::FLOAT;
2010   float f = t1->getf();
2011   if( f < 0.0f ) return Type::FLOAT;
2012   return TypeF::make( (float)sqrt( (double)f ) );
2013 }
2014 
2015 const Type* SqrtHFNode::Value(PhaseGVN* phase) const {
2016   const Type* t1 = phase->type(in(1));
2017   if (t1 == Type::TOP) { return Type::TOP; }
2018   if (t1->base() != Type::HalfFloatCon) { return Type::HALF_FLOAT; }
2019   float f = t1->getf();
2020   if (f < 0.0f) return Type::HALF_FLOAT;
2021   return TypeH::make((float)sqrt((double)f));
2022 }
2023 
2024 const Type* ReverseINode::Value(PhaseGVN* phase) const {
2025   const Type *t1 = phase->type( in(1) );
2026   if (t1 == Type::TOP) {
2027     return Type::TOP;
2028   }
2029   const TypeInt* t1int = t1->isa_int();
2030   if (t1int && t1int->is_con()) {
2031     jint res = reverse_bits(t1int->get_con());
2032     return TypeInt::make(res);
2033   }
2034   return bottom_type();
2035 }
2036 
2037 const Type* ReverseLNode::Value(PhaseGVN* phase) const {
2038   const Type *t1 = phase->type( in(1) );
2039   if (t1 == Type::TOP) {
2040     return Type::TOP;
2041   }
2042   const TypeLong* t1long = t1->isa_long();
2043   if (t1long && t1long->is_con()) {
2044     jlong res = reverse_bits(t1long->get_con());
2045     return TypeLong::make(res);
2046   }
2047   return bottom_type();
2048 }
2049 
2050 Node* InvolutionNode::Identity(PhaseGVN* phase) {
2051   // Op ( Op x ) => x
2052   if (in(1)->Opcode() == Opcode()) {
2053     return in(1)->in(1);
2054   }
2055   return this;
2056 }