1 /*
   2  * Copyright (c) 1997, 2018, 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.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "gc/shared/barrierSet.hpp"
  28 #include "gc/shared/c2/barrierSetC2.hpp"
  29 #include "memory/allocation.inline.hpp"
  30 #include "opto/addnode.hpp"
  31 #include "opto/callnode.hpp"
  32 #include "opto/cfgnode.hpp"
  33 #include "opto/loopnode.hpp"
  34 #include "opto/matcher.hpp"
  35 #include "opto/movenode.hpp"
  36 #include "opto/mulnode.hpp"
  37 #include "opto/opcodes.hpp"
  38 #include "opto/phaseX.hpp"
  39 #include "opto/subnode.hpp"
  40 #include "runtime/sharedRuntime.hpp"
  41 
  42 // Portions of code courtesy of Clifford Click
  43 
  44 // Optimization - Graph Style
  45 
  46 #include "math.h"
  47 
  48 //=============================================================================
  49 //------------------------------Identity---------------------------------------
  50 // If right input is a constant 0, return the left input.
  51 Node* SubNode::Identity(PhaseGVN* phase) {
  52   assert(in(1) != this, "Must already have called Value");
  53   assert(in(2) != this, "Must already have called Value");
  54 
  55   // Remove double negation
  56   const Type *zero = add_id();
  57   if( phase->type( in(1) )->higher_equal( zero ) &&
  58       in(2)->Opcode() == Opcode() &&
  59       phase->type( in(2)->in(1) )->higher_equal( zero ) ) {
  60     return in(2)->in(2);
  61   }
  62 
  63   // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y
  64   if( in(1)->Opcode() == Op_AddI ) {
  65     if( phase->eqv(in(1)->in(2),in(2)) )
  66       return in(1)->in(1);
  67     if (phase->eqv(in(1)->in(1),in(2)))
  68       return in(1)->in(2);
  69 
  70     // Also catch: "(X + Opaque2(Y)) - Y".  In this case, 'Y' is a loop-varying
  71     // trip counter and X is likely to be loop-invariant (that's how O2 Nodes
  72     // are originally used, although the optimizer sometimes jiggers things).
  73     // This folding through an O2 removes a loop-exit use of a loop-varying
  74     // value and generally lowers register pressure in and around the loop.
  75     if( in(1)->in(2)->Opcode() == Op_Opaque2 &&
  76         phase->eqv(in(1)->in(2)->in(1),in(2)) )
  77       return in(1)->in(1);
  78   }
  79 
  80   return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this;
  81 }
  82 
  83 //------------------------------Value------------------------------------------
  84 // A subtract node differences it's two inputs.
  85 const Type* SubNode::Value_common(PhaseTransform *phase) const {
  86   const Node* in1 = in(1);
  87   const Node* in2 = in(2);
  88   // Either input is TOP ==> the result is TOP
  89   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  90   if( t1 == Type::TOP ) return Type::TOP;
  91   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  92   if( t2 == Type::TOP ) return Type::TOP;
  93 
  94   // Not correct for SubFnode and AddFNode (must check for infinity)
  95   // Equal?  Subtract is zero
  96   if (in1->eqv_uncast(in2))  return add_id();
  97 
  98   // Either input is BOTTOM ==> the result is the local BOTTOM
  99   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
 100     return bottom_type();
 101 
 102   return NULL;
 103 }
 104 
 105 const Type* SubNode::Value(PhaseGVN* phase) const {
 106   const Type* t = Value_common(phase);
 107   if (t != NULL) {
 108     return t;
 109   }
 110   const Type* t1 = phase->type(in(1));
 111   const Type* t2 = phase->type(in(2));
 112   return sub(t1,t2);            // Local flavor of type subtraction
 113 
 114 }
 115 
 116 //=============================================================================
 117 //------------------------------Helper function--------------------------------
 118 
 119 static bool is_cloop_increment(Node* inc) {
 120   precond(inc->Opcode() == Op_AddI || inc->Opcode() == Op_AddL);
 121 
 122   if (!inc->in(1)->is_Phi()) {
 123     return false;
 124   }
 125   const PhiNode* phi = inc->in(1)->as_Phi();
 126 
 127   if (phi->is_copy() || !phi->region()->is_CountedLoop()) {
 128     return false;
 129   }
 130 
 131   return inc == phi->region()->as_CountedLoop()->incr();
 132 }
 133 
 134 // Given the expression '(x + C) - v', or
 135 //                      'v - (x + C)', we examine nodes '+' and 'v':
 136 //
 137 //  1. Do not convert if '+' is a counted-loop increment, because the '-' is
 138 //     loop invariant and converting extends the live-range of 'x' to overlap
 139 //     with the '+', forcing another register to be used in the loop.
 140 //
 141 //  2. Do not convert if 'v' is a counted-loop induction variable, because
 142 //     'x' might be invariant.
 143 //
 144 static bool ok_to_convert(Node* inc, Node* var) {
 145   return !(is_cloop_increment(inc) || var->is_cloop_ind_var());
 146 }
 147 
 148 //------------------------------Ideal------------------------------------------
 149 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
 150   Node *in1 = in(1);
 151   Node *in2 = in(2);
 152   uint op1 = in1->Opcode();
 153   uint op2 = in2->Opcode();
 154 
 155 #ifdef ASSERT
 156   // Check for dead loop
 157   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 158       ( ( op1 == Op_AddI || op1 == Op_SubI ) &&
 159         ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 160           phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1 ) ) ) )
 161     assert(false, "dead loop in SubINode::Ideal");
 162 #endif
 163 
 164   const Type *t2 = phase->type( in2 );
 165   if( t2 == Type::TOP ) return NULL;
 166   // Convert "x-c0" into "x+ -c0".
 167   if( t2->base() == Type::Int ){        // Might be bottom or top...
 168     const TypeInt *i = t2->is_int();
 169     if( i->is_con() )
 170       return new AddINode(in1, phase->intcon(-i->get_con()));
 171   }
 172 
 173   // Convert "(x+c0) - y" into (x-y) + c0"
 174   // Do not collapse (x+c0)-y if "+" is a loop increment or
 175   // if "y" is a loop induction variable.
 176   if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
 177     const Type *tadd = phase->type( in1->in(2) );
 178     if( tadd->singleton() && tadd != Type::TOP ) {
 179       Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 ));
 180       return new AddINode( sub2, in1->in(2) );
 181     }
 182   }
 183 
 184 
 185   // Convert "x - (y+c0)" into "(x-y) - c0"
 186   // Need the same check as in above optimization but reversed.
 187   if (op2 == Op_AddI && ok_to_convert(in2, in1)) {
 188     Node* in21 = in2->in(1);
 189     Node* in22 = in2->in(2);
 190     const TypeInt* tcon = phase->type(in22)->isa_int();
 191     if (tcon != NULL && tcon->is_con()) {
 192       Node* sub2 = phase->transform( new SubINode(in1, in21) );
 193       Node* neg_c0 = phase->intcon(- tcon->get_con());
 194       return new AddINode(sub2, neg_c0);
 195     }
 196   }
 197 
 198   const Type *t1 = phase->type( in1 );
 199   if( t1 == Type::TOP ) return NULL;
 200 
 201 #ifdef ASSERT
 202   // Check for dead loop
 203   if( ( op2 == Op_AddI || op2 == Op_SubI ) &&
 204       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 205         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 206     assert(false, "dead loop in SubINode::Ideal");
 207 #endif
 208 
 209   // Convert "x - (x+y)" into "-y"
 210   if( op2 == Op_AddI &&
 211       phase->eqv( in1, in2->in(1) ) )
 212     return new SubINode( phase->intcon(0),in2->in(2));
 213   // Convert "(x-y) - x" into "-y"
 214   if( op1 == Op_SubI &&
 215       phase->eqv( in1->in(1), in2 ) )
 216     return new SubINode( phase->intcon(0),in1->in(2));
 217   // Convert "x - (y+x)" into "-y"
 218   if( op2 == Op_AddI &&
 219       phase->eqv( in1, in2->in(2) ) )
 220     return new SubINode( phase->intcon(0),in2->in(1));
 221 
 222   // Convert "0 - (x-y)" into "y-x"
 223   if( t1 == TypeInt::ZERO && op2 == Op_SubI )
 224     return new SubINode( in2->in(2), in2->in(1) );
 225 
 226   // Convert "0 - (x+con)" into "-con-x"
 227   jint con;
 228   if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
 229       (con = in2->in(2)->find_int_con(0)) != 0 )
 230     return new SubINode( phase->intcon(-con), in2->in(1) );
 231 
 232   // Convert "(X+A) - (X+B)" into "A - B"
 233   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
 234     return new SubINode( in1->in(2), in2->in(2) );
 235 
 236   // Convert "(A+X) - (B+X)" into "A - B"
 237   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
 238     return new SubINode( in1->in(1), in2->in(1) );
 239 
 240   // Convert "(A+X) - (X+B)" into "A - B"
 241   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
 242     return new SubINode( in1->in(1), in2->in(2) );
 243 
 244   // Convert "(X+A) - (B+X)" into "A - B"
 245   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
 246     return new SubINode( in1->in(2), in2->in(1) );
 247 
 248   // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
 249   // nicer to optimize than subtract.
 250   if( op2 == Op_SubI && in2->outcnt() == 1) {
 251     Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) );
 252     return new SubINode( add1, in2->in(1) );
 253   }
 254 
 255   return NULL;
 256 }
 257 
 258 //------------------------------sub--------------------------------------------
 259 // A subtract node differences it's two inputs.
 260 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
 261   const TypeInt *r0 = t1->is_int(); // Handy access
 262   const TypeInt *r1 = t2->is_int();
 263   int32_t lo = java_subtract(r0->_lo, r1->_hi);
 264   int32_t hi = java_subtract(r0->_hi, r1->_lo);
 265 
 266   // We next check for 32-bit overflow.
 267   // If that happens, we just assume all integers are possible.
 268   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 269        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 270       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 271        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 272     return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 273   else                          // Overflow; assume all integers
 274     return TypeInt::INT;
 275 }
 276 
 277 //=============================================================================
 278 //------------------------------Ideal------------------------------------------
 279 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 280   Node *in1 = in(1);
 281   Node *in2 = in(2);
 282   uint op1 = in1->Opcode();
 283   uint op2 = in2->Opcode();
 284 
 285 #ifdef ASSERT
 286   // Check for dead loop
 287   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 288       ( ( op1 == Op_AddL || op1 == Op_SubL ) &&
 289         ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 290           phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1  ) ) ) )
 291     assert(false, "dead loop in SubLNode::Ideal");
 292 #endif
 293 
 294   if( phase->type( in2 ) == Type::TOP ) return NULL;
 295   const TypeLong *i = phase->type( in2 )->isa_long();
 296   // Convert "x-c0" into "x+ -c0".
 297   if( i &&                      // Might be bottom or top...
 298       i->is_con() )
 299     return new AddLNode(in1, phase->longcon(-i->get_con()));
 300 
 301   // Convert "(x+c0) - y" into (x-y) + c0"
 302   // Do not collapse (x+c0)-y if "+" is a loop increment or
 303   // if "y" is a loop induction variable.
 304   if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
 305     Node *in11 = in1->in(1);
 306     const Type *tadd = phase->type( in1->in(2) );
 307     if( tadd->singleton() && tadd != Type::TOP ) {
 308       Node *sub2 = phase->transform( new SubLNode( in11, in2 ));
 309       return new AddLNode( sub2, in1->in(2) );
 310     }
 311   }
 312 
 313   // Convert "x - (y+c0)" into "(x-y) - c0"
 314   // Need the same check as in above optimization but reversed.
 315   if (op2 == Op_AddL && ok_to_convert(in2, in1)) {
 316     Node* in21 = in2->in(1);
 317     Node* in22 = in2->in(2);
 318     const TypeLong* tcon = phase->type(in22)->isa_long();
 319     if (tcon != NULL && tcon->is_con()) {
 320       Node* sub2 = phase->transform( new SubLNode(in1, in21) );
 321       Node* neg_c0 = phase->longcon(- tcon->get_con());
 322       return new AddLNode(sub2, neg_c0);
 323     }
 324   }
 325 
 326   const Type *t1 = phase->type( in1 );
 327   if( t1 == Type::TOP ) return NULL;
 328 
 329 #ifdef ASSERT
 330   // Check for dead loop
 331   if( ( op2 == Op_AddL || op2 == Op_SubL ) &&
 332       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 333         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 334     assert(false, "dead loop in SubLNode::Ideal");
 335 #endif
 336 
 337   // Convert "x - (x+y)" into "-y"
 338   if( op2 == Op_AddL &&
 339       phase->eqv( in1, in2->in(1) ) )
 340     return new SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2));
 341   // Convert "x - (y+x)" into "-y"
 342   if( op2 == Op_AddL &&
 343       phase->eqv( in1, in2->in(2) ) )
 344     return new SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1));
 345 
 346   // Convert "0 - (x-y)" into "y-x"
 347   if( phase->type( in1 ) == TypeLong::ZERO && op2 == Op_SubL )
 348     return new SubLNode( in2->in(2), in2->in(1) );
 349 
 350   // Convert "(X+A) - (X+B)" into "A - B"
 351   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
 352     return new SubLNode( in1->in(2), in2->in(2) );
 353 
 354   // Convert "(A+X) - (B+X)" into "A - B"
 355   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
 356     return new SubLNode( in1->in(1), in2->in(1) );
 357 
 358   // Convert "A-(B-C)" into (A+C)-B"
 359   if( op2 == Op_SubL && in2->outcnt() == 1) {
 360     Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) );
 361     return new SubLNode( add1, in2->in(1) );
 362   }
 363 
 364   return NULL;
 365 }
 366 
 367 //------------------------------sub--------------------------------------------
 368 // A subtract node differences it's two inputs.
 369 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
 370   const TypeLong *r0 = t1->is_long(); // Handy access
 371   const TypeLong *r1 = t2->is_long();
 372   jlong lo = java_subtract(r0->_lo, r1->_hi);
 373   jlong hi = java_subtract(r0->_hi, r1->_lo);
 374 
 375   // We next check for 32-bit overflow.
 376   // If that happens, we just assume all integers are possible.
 377   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 378        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 379       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 380        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 381     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 382   else                          // Overflow; assume all integers
 383     return TypeLong::LONG;
 384 }
 385 
 386 //=============================================================================
 387 //------------------------------Value------------------------------------------
 388 // A subtract node differences its two inputs.
 389 const Type* SubFPNode::Value(PhaseGVN* phase) const {
 390   const Node* in1 = in(1);
 391   const Node* in2 = in(2);
 392   // Either input is TOP ==> the result is TOP
 393   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 394   if( t1 == Type::TOP ) return Type::TOP;
 395   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 396   if( t2 == Type::TOP ) return Type::TOP;
 397 
 398   // if both operands are infinity of same sign, the result is NaN; do
 399   // not replace with zero
 400   if( (t1->is_finite() && t2->is_finite()) ) {
 401     if( phase->eqv(in1, in2) ) return add_id();
 402   }
 403 
 404   // Either input is BOTTOM ==> the result is the local BOTTOM
 405   const Type *bot = bottom_type();
 406   if( (t1 == bot) || (t2 == bot) ||
 407       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 408     return bot;
 409 
 410   return sub(t1,t2);            // Local flavor of type subtraction
 411 }
 412 
 413 
 414 //=============================================================================
 415 //------------------------------Ideal------------------------------------------
 416 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 417   const Type *t2 = phase->type( in(2) );
 418   // Convert "x-c0" into "x+ -c0".
 419   if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
 420     // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
 421   }
 422 
 423   // Not associative because of boundary conditions (infinity)
 424   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 425     // Convert "x - (x+y)" into "-y"
 426     if( in(2)->is_Add() &&
 427         phase->eqv(in(1),in(2)->in(1) ) )
 428       return new SubFNode( phase->makecon(TypeF::ZERO),in(2)->in(2));
 429   }
 430 
 431   // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
 432   // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
 433   //if( phase->type(in(1)) == TypeF::ZERO )
 434   //return new (phase->C, 2) NegFNode(in(2));
 435 
 436   return NULL;
 437 }
 438 
 439 //------------------------------sub--------------------------------------------
 440 // A subtract node differences its two inputs.
 441 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
 442   // no folding if one of operands is infinity or NaN, do not do constant folding
 443   if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
 444     return TypeF::make( t1->getf() - t2->getf() );
 445   }
 446   else if( g_isnan(t1->getf()) ) {
 447     return t1;
 448   }
 449   else if( g_isnan(t2->getf()) ) {
 450     return t2;
 451   }
 452   else {
 453     return Type::FLOAT;
 454   }
 455 }
 456 
 457 //=============================================================================
 458 //------------------------------Ideal------------------------------------------
 459 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 460   const Type *t2 = phase->type( in(2) );
 461   // Convert "x-c0" into "x+ -c0".
 462   if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
 463     // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
 464   }
 465 
 466   // Not associative because of boundary conditions (infinity)
 467   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 468     // Convert "x - (x+y)" into "-y"
 469     if( in(2)->is_Add() &&
 470         phase->eqv(in(1),in(2)->in(1) ) )
 471       return new SubDNode( phase->makecon(TypeD::ZERO),in(2)->in(2));
 472   }
 473 
 474   // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
 475   // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
 476   //if( phase->type(in(1)) == TypeD::ZERO )
 477   //return new (phase->C, 2) NegDNode(in(2));
 478 
 479   return NULL;
 480 }
 481 
 482 //------------------------------sub--------------------------------------------
 483 // A subtract node differences its two inputs.
 484 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
 485   // no folding if one of operands is infinity or NaN, do not do constant folding
 486   if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
 487     return TypeD::make( t1->getd() - t2->getd() );
 488   }
 489   else if( g_isnan(t1->getd()) ) {
 490     return t1;
 491   }
 492   else if( g_isnan(t2->getd()) ) {
 493     return t2;
 494   }
 495   else {
 496     return Type::DOUBLE;
 497   }
 498 }
 499 
 500 //=============================================================================
 501 //------------------------------Idealize---------------------------------------
 502 // Unlike SubNodes, compare must still flatten return value to the
 503 // range -1, 0, 1.
 504 // And optimizations like those for (X + Y) - X fail if overflow happens.
 505 Node* CmpNode::Identity(PhaseGVN* phase) {
 506   return this;
 507 }
 508 
 509 #ifndef PRODUCT
 510 //----------------------------related------------------------------------------
 511 // Related nodes of comparison nodes include all data inputs (until hitting a
 512 // control boundary) as well as all outputs until and including control nodes
 513 // as well as their projections. In compact mode, data inputs till depth 1 and
 514 // all outputs till depth 1 are considered.
 515 void CmpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
 516   if (compact) {
 517     this->collect_nodes(in_rel, 1, false, true);
 518     this->collect_nodes(out_rel, -1, false, false);
 519   } else {
 520     this->collect_nodes_in_all_data(in_rel, false);
 521     this->collect_nodes_out_all_ctrl_boundary(out_rel);
 522     // Now, find all control nodes in out_rel, and include their projections
 523     // and projection targets (if any) in the result.
 524     GrowableArray<Node*> proj(Compile::current()->unique());
 525     for (GrowableArrayIterator<Node*> it = out_rel->begin(); it != out_rel->end(); ++it) {
 526       Node* n = *it;
 527       if (n->is_CFG() && !n->is_Proj()) {
 528         // Assume projections and projection targets are found at levels 1 and 2.
 529         n->collect_nodes(&proj, -2, false, false);
 530         for (GrowableArrayIterator<Node*> p = proj.begin(); p != proj.end(); ++p) {
 531           out_rel->append_if_missing(*p);
 532         }
 533         proj.clear();
 534       }
 535     }
 536   }
 537 }
 538 #endif
 539 
 540 //=============================================================================
 541 //------------------------------cmp--------------------------------------------
 542 // Simplify a CmpI (compare 2 integers) node, based on local information.
 543 // If both inputs are constants, compare them.
 544 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 545   const TypeInt *r0 = t1->is_int(); // Handy access
 546   const TypeInt *r1 = t2->is_int();
 547 
 548   if( r0->_hi < r1->_lo )       // Range is always low?
 549     return TypeInt::CC_LT;
 550   else if( r0->_lo > r1->_hi )  // Range is always high?
 551     return TypeInt::CC_GT;
 552 
 553   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 554     assert(r0->get_con() == r1->get_con(), "must be equal");
 555     return TypeInt::CC_EQ;      // Equal results.
 556   } else if( r0->_hi == r1->_lo ) // Range is never high?
 557     return TypeInt::CC_LE;
 558   else if( r0->_lo == r1->_hi ) // Range is never low?
 559     return TypeInt::CC_GE;
 560   return TypeInt::CC;           // else use worst case results
 561 }
 562 
 563 // Simplify a CmpU (compare 2 integers) node, based on local information.
 564 // If both inputs are constants, compare them.
 565 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 566   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 567 
 568   // comparing two unsigned ints
 569   const TypeInt *r0 = t1->is_int();   // Handy access
 570   const TypeInt *r1 = t2->is_int();
 571 
 572   // Current installed version
 573   // Compare ranges for non-overlap
 574   juint lo0 = r0->_lo;
 575   juint hi0 = r0->_hi;
 576   juint lo1 = r1->_lo;
 577   juint hi1 = r1->_hi;
 578 
 579   // If either one has both negative and positive values,
 580   // it therefore contains both 0 and -1, and since [0..-1] is the
 581   // full unsigned range, the type must act as an unsigned bottom.
 582   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 583   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 584 
 585   if (bot0 || bot1) {
 586     // All unsigned values are LE -1 and GE 0.
 587     if (lo0 == 0 && hi0 == 0) {
 588       return TypeInt::CC_LE;            //   0 <= bot
 589     } else if ((jint)lo0 == -1 && (jint)hi0 == -1) {
 590       return TypeInt::CC_GE;            // -1 >= bot
 591     } else if (lo1 == 0 && hi1 == 0) {
 592       return TypeInt::CC_GE;            // bot >= 0
 593     } else if ((jint)lo1 == -1 && (jint)hi1 == -1) {
 594       return TypeInt::CC_LE;            // bot <= -1
 595     }
 596   } else {
 597     // We can use ranges of the form [lo..hi] if signs are the same.
 598     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 599     // results are reversed, '-' > '+' for unsigned compare
 600     if (hi0 < lo1) {
 601       return TypeInt::CC_LT;            // smaller
 602     } else if (lo0 > hi1) {
 603       return TypeInt::CC_GT;            // greater
 604     } else if (hi0 == lo1 && lo0 == hi1) {
 605       return TypeInt::CC_EQ;            // Equal results
 606     } else if (lo0 >= hi1) {
 607       return TypeInt::CC_GE;
 608     } else if (hi0 <= lo1) {
 609       // Check for special case in Hashtable::get.  (See below.)
 610       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 611         return TypeInt::CC_LT;
 612       return TypeInt::CC_LE;
 613     }
 614   }
 615   // Check for special case in Hashtable::get - the hash index is
 616   // mod'ed to the table size so the following range check is useless.
 617   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 618   // to be positive.
 619   // (This is a gross hack, since the sub method never
 620   // looks at the structure of the node in any other case.)
 621   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 622     return TypeInt::CC_LT;
 623   return TypeInt::CC;                   // else use worst case results
 624 }
 625 
 626 const Type* CmpUNode::Value(PhaseGVN* phase) const {
 627   const Type* t = SubNode::Value_common(phase);
 628   if (t != NULL) {
 629     return t;
 630   }
 631   const Node* in1 = in(1);
 632   const Node* in2 = in(2);
 633   const Type* t1 = phase->type(in1);
 634   const Type* t2 = phase->type(in2);
 635   assert(t1->isa_int(), "CmpU has only Int type inputs");
 636   if (t2 == TypeInt::INT) { // Compare to bottom?
 637     return bottom_type();
 638   }
 639   uint in1_op = in1->Opcode();
 640   if (in1_op == Op_AddI || in1_op == Op_SubI) {
 641     // The problem rise when result of AddI(SubI) may overflow
 642     // signed integer value. Let say the input type is
 643     // [256, maxint] then +128 will create 2 ranges due to
 644     // overflow: [minint, minint+127] and [384, maxint].
 645     // But C2 type system keep only 1 type range and as result
 646     // it use general [minint, maxint] for this case which we
 647     // can't optimize.
 648     //
 649     // Make 2 separate type ranges based on types of AddI(SubI) inputs
 650     // and compare results of their compare. If results are the same
 651     // CmpU node can be optimized.
 652     const Node* in11 = in1->in(1);
 653     const Node* in12 = in1->in(2);
 654     const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11);
 655     const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12);
 656     // Skip cases when input types are top or bottom.
 657     if ((t11 != Type::TOP) && (t11 != TypeInt::INT) &&
 658         (t12 != Type::TOP) && (t12 != TypeInt::INT)) {
 659       const TypeInt *r0 = t11->is_int();
 660       const TypeInt *r1 = t12->is_int();
 661       jlong lo_r0 = r0->_lo;
 662       jlong hi_r0 = r0->_hi;
 663       jlong lo_r1 = r1->_lo;
 664       jlong hi_r1 = r1->_hi;
 665       if (in1_op == Op_SubI) {
 666         jlong tmp = hi_r1;
 667         hi_r1 = -lo_r1;
 668         lo_r1 = -tmp;
 669         // Note, for substructing [minint,x] type range
 670         // long arithmetic provides correct overflow answer.
 671         // The confusion come from the fact that in 32-bit
 672         // -minint == minint but in 64-bit -minint == maxint+1.
 673       }
 674       jlong lo_long = lo_r0 + lo_r1;
 675       jlong hi_long = hi_r0 + hi_r1;
 676       int lo_tr1 = min_jint;
 677       int hi_tr1 = (int)hi_long;
 678       int lo_tr2 = (int)lo_long;
 679       int hi_tr2 = max_jint;
 680       bool underflow = lo_long != (jlong)lo_tr2;
 681       bool overflow  = hi_long != (jlong)hi_tr1;
 682       // Use sub(t1, t2) when there is no overflow (one type range)
 683       // or when both overflow and underflow (too complex).
 684       if ((underflow != overflow) && (hi_tr1 < lo_tr2)) {
 685         // Overflow only on one boundary, compare 2 separate type ranges.
 686         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
 687         const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w);
 688         const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w);
 689         const Type* cmp1 = sub(tr1, t2);
 690         const Type* cmp2 = sub(tr2, t2);
 691         if (cmp1 == cmp2) {
 692           return cmp1; // Hit!
 693         }
 694       }
 695     }
 696   }
 697 
 698   return sub(t1, t2);            // Local flavor of type subtraction
 699 }
 700 
 701 bool CmpUNode::is_index_range_check() const {
 702   // Check for the "(X ModI Y) CmpU Y" shape
 703   return (in(1)->Opcode() == Op_ModI &&
 704           in(1)->in(2)->eqv_uncast(in(2)));
 705 }
 706 
 707 //------------------------------Idealize---------------------------------------
 708 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 709   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 710     switch (in(1)->Opcode()) {
 711     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 712       return new CmpLNode(in(1)->in(1),in(1)->in(2));
 713     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 714       return new CmpFNode(in(1)->in(1),in(1)->in(2));
 715     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 716       return new CmpDNode(in(1)->in(1),in(1)->in(2));
 717     //case Op_SubI:
 718       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 719       // can be turned into (x <?> y).
 720       // This is handled (with more general cases) by Ideal_sub_algebra.
 721     }
 722   }
 723   return NULL;                  // No change
 724 }
 725 
 726 //------------------------------Ideal------------------------------------------
 727 Node* CmpLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 728   Node* a = NULL;
 729   Node* b = NULL;
 730   if (is_double_null_check(phase, a, b) && (phase->type(a)->is_zero_type() || phase->type(b)->is_zero_type())) {
 731     // Degraded to a simple null check, use old acmp
 732     return new CmpPNode(a, b);
 733   }
 734   return NULL;
 735 }
 736 
 737 // Match double null check emitted by Compile::optimize_acmp()
 738 bool CmpLNode::is_double_null_check(PhaseGVN* phase, Node*& a, Node*& b) const {
 739   if (in(1)->Opcode() == Op_OrL &&
 740       in(1)->in(1)->Opcode() == Op_CastP2X &&
 741       in(1)->in(2)->Opcode() == Op_CastP2X &&
 742       in(2)->bottom_type()->is_zero_type()) {
 743     assert(EnableValhalla, "unexpected double null check");
 744     a = in(1)->in(1)->in(1);
 745     b = in(1)->in(2)->in(1);
 746     return true;
 747   }
 748   return false;
 749 }
 750 
 751 //------------------------------Value------------------------------------------
 752 const Type* CmpLNode::Value(PhaseGVN* phase) const {
 753   Node* a = NULL;
 754   Node* b = NULL;
 755   if (is_double_null_check(phase, a, b) && (!phase->type(a)->maybe_null() || !phase->type(b)->maybe_null())) {
 756     // One operand is never NULL, emit constant false
 757     return TypeInt::CC_GT;
 758   }
 759   return SubNode::Value(phase);
 760 }
 761 
 762 //=============================================================================
 763 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 764 // If both inputs are constants, compare them.
 765 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 766   const TypeLong *r0 = t1->is_long(); // Handy access
 767   const TypeLong *r1 = t2->is_long();
 768 
 769   if( r0->_hi < r1->_lo )       // Range is always low?
 770     return TypeInt::CC_LT;
 771   else if( r0->_lo > r1->_hi )  // Range is always high?
 772     return TypeInt::CC_GT;
 773 
 774   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 775     assert(r0->get_con() == r1->get_con(), "must be equal");
 776     return TypeInt::CC_EQ;      // Equal results.
 777   } else if( r0->_hi == r1->_lo ) // Range is never high?
 778     return TypeInt::CC_LE;
 779   else if( r0->_lo == r1->_hi ) // Range is never low?
 780     return TypeInt::CC_GE;
 781   return TypeInt::CC;           // else use worst case results
 782 }
 783 
 784 
 785 // Simplify a CmpUL (compare 2 unsigned longs) node, based on local information.
 786 // If both inputs are constants, compare them.
 787 const Type* CmpULNode::sub(const Type* t1, const Type* t2) const {
 788   assert(!t1->isa_ptr(), "obsolete usage of CmpUL");
 789 
 790   // comparing two unsigned longs
 791   const TypeLong* r0 = t1->is_long();   // Handy access
 792   const TypeLong* r1 = t2->is_long();
 793 
 794   // Current installed version
 795   // Compare ranges for non-overlap
 796   julong lo0 = r0->_lo;
 797   julong hi0 = r0->_hi;
 798   julong lo1 = r1->_lo;
 799   julong hi1 = r1->_hi;
 800 
 801   // If either one has both negative and positive values,
 802   // it therefore contains both 0 and -1, and since [0..-1] is the
 803   // full unsigned range, the type must act as an unsigned bottom.
 804   bool bot0 = ((jlong)(lo0 ^ hi0) < 0);
 805   bool bot1 = ((jlong)(lo1 ^ hi1) < 0);
 806 
 807   if (bot0 || bot1) {
 808     // All unsigned values are LE -1 and GE 0.
 809     if (lo0 == 0 && hi0 == 0) {
 810       return TypeInt::CC_LE;            //   0 <= bot
 811     } else if ((jlong)lo0 == -1 && (jlong)hi0 == -1) {
 812       return TypeInt::CC_GE;            // -1 >= bot
 813     } else if (lo1 == 0 && hi1 == 0) {
 814       return TypeInt::CC_GE;            // bot >= 0
 815     } else if ((jlong)lo1 == -1 && (jlong)hi1 == -1) {
 816       return TypeInt::CC_LE;            // bot <= -1
 817     }
 818   } else {
 819     // We can use ranges of the form [lo..hi] if signs are the same.
 820     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 821     // results are reversed, '-' > '+' for unsigned compare
 822     if (hi0 < lo1) {
 823       return TypeInt::CC_LT;            // smaller
 824     } else if (lo0 > hi1) {
 825       return TypeInt::CC_GT;            // greater
 826     } else if (hi0 == lo1 && lo0 == hi1) {
 827       return TypeInt::CC_EQ;            // Equal results
 828     } else if (lo0 >= hi1) {
 829       return TypeInt::CC_GE;
 830     } else if (hi0 <= lo1) {
 831       return TypeInt::CC_LE;
 832     }
 833   }
 834 
 835   return TypeInt::CC;                   // else use worst case results
 836 }
 837 
 838 //=============================================================================
 839 //------------------------------sub--------------------------------------------
 840 // Simplify an CmpP (compare 2 pointers) node, based on local information.
 841 // If both inputs are constants, compare them.
 842 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
 843   const TypePtr *r0 = t1->is_ptr(); // Handy access
 844   const TypePtr *r1 = t2->is_ptr();
 845 
 846   // Undefined inputs makes for an undefined result
 847   if( TypePtr::above_centerline(r0->_ptr) ||
 848       TypePtr::above_centerline(r1->_ptr) )
 849     return Type::TOP;
 850 
 851   if (r0 == r1 && r0->singleton()) {
 852     // Equal pointer constants (klasses, nulls, etc.)
 853     return TypeInt::CC_EQ;
 854   }
 855 
 856   // See if it is 2 unrelated classes.
 857   const TypeOopPtr* p0 = r0->isa_oopptr();
 858   const TypeOopPtr* p1 = r1->isa_oopptr();
 859   if (p0 && p1) {
 860     Node* in1 = in(1)->uncast();
 861     Node* in2 = in(2)->uncast();
 862     AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
 863     AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
 864     if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
 865       return TypeInt::CC_GT;  // different pointers
 866     }
 867     ciKlass* klass0 = p0->klass();
 868     bool    xklass0 = p0->klass_is_exact();
 869     ciKlass* klass1 = p1->klass();
 870     bool    xklass1 = p1->klass_is_exact();
 871     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 872     if (klass0 && klass1 &&
 873         kps != 1 &&             // both or neither are klass pointers
 874         klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
 875         klass1->is_loaded() && !klass1->is_interface() &&
 876         (!klass0->is_obj_array_klass() ||
 877          !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
 878         (!klass1->is_obj_array_klass() ||
 879          !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
 880       bool unrelated_classes = false;
 881       // See if neither subclasses the other, or if the class on top
 882       // is precise.  In either of these cases, the compare is known
 883       // to fail if at least one of the pointers is provably not null.
 884       if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
 885         // Do nothing; we know nothing for imprecise types
 886       } else if (klass0->is_subtype_of(klass1)) {
 887         // If klass1's type is PRECISE, then classes are unrelated.
 888         unrelated_classes = xklass1;
 889       } else if (klass1->is_subtype_of(klass0)) {
 890         // If klass0's type is PRECISE, then classes are unrelated.
 891         unrelated_classes = xklass0;
 892       } else {                  // Neither subtypes the other
 893         unrelated_classes = true;
 894       }
 895       if (unrelated_classes) {
 896         // The oops classes are known to be unrelated. If the joined PTRs of
 897         // two oops is not Null and not Bottom, then we are sure that one
 898         // of the two oops is non-null, and the comparison will always fail.
 899         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 900         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 901           return TypeInt::CC_GT;
 902         }
 903       }
 904     }
 905   }
 906 
 907   // Known constants can be compared exactly
 908   // Null can be distinguished from any NotNull pointers
 909   // Unknown inputs makes an unknown result
 910   if( r0->singleton() ) {
 911     intptr_t bits0 = r0->get_con();
 912     if( r1->singleton() )
 913       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 914     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 915   } else if( r1->singleton() ) {
 916     intptr_t bits1 = r1->get_con();
 917     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 918   } else
 919     return TypeInt::CC;
 920 }
 921 
 922 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
 923   // Return the klass node for (indirect load from OopHandle)
 924   //   LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
 925   //   or NULL if not matching.
 926   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 927     n = bs->step_over_gc_barrier(n);
 928 
 929   if (n->Opcode() != Op_LoadP) return NULL;
 930 
 931   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 932   if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;
 933 
 934   Node* adr = n->in(MemNode::Address);
 935   // First load from OopHandle: ((OopHandle)mirror)->resolve(); may need barrier.
 936   if (adr->Opcode() != Op_LoadP || !phase->type(adr)->isa_rawptr()) return NULL;
 937   adr = adr->in(MemNode::Address);
 938 
 939   intptr_t off = 0;
 940   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
 941   if (k == NULL)  return NULL;
 942   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
 943   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL;
 944 
 945   // We've found the klass node of a Java mirror load.
 946   return k;
 947 }
 948 
 949 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
 950   // for ConP(Foo.class) return ConP(Foo.klass)
 951   // otherwise return NULL
 952   if (!n->is_Con()) return NULL;
 953 
 954   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 955   if (!tp) return NULL;
 956 
 957   ciType* mirror_type = tp->java_mirror_type();
 958   // TypeInstPtr::java_mirror_type() returns non-NULL for compile-
 959   // time Class constants only.
 960   if (!mirror_type) return NULL;
 961 
 962   // x.getClass() == int.class can never be true (for all primitive types)
 963   // Return a ConP(NULL) node for this case.
 964   if (mirror_type->is_classless()) {
 965     return phase->makecon(TypePtr::NULL_PTR);
 966   }
 967 
 968   // return the ConP(Foo.klass)
 969   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
 970   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass()));
 971 }
 972 
 973 //------------------------------Ideal------------------------------------------
 974 // Normalize comparisons between Java mirror loads to compare the klass instead.
 975 //
 976 // Also check for the case of comparing an unknown klass loaded from the primary
 977 // super-type array vs a known klass with no subtypes.  This amounts to
 978 // checking to see an unknown klass subtypes a known klass with no subtypes;
 979 // this only happens on an exact match.  We can shorten this test by 1 load.
 980 Node* CmpPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 981   // Normalize comparisons between Java mirrors into comparisons of the low-
 982   // level klass, where a dependent load could be shortened.
 983   //
 984   // The new pattern has a nice effect of matching the same pattern used in the
 985   // fast path of instanceof/checkcast/Class.isInstance(), which allows
 986   // redundant exact type check be optimized away by GVN.
 987   // For example, in
 988   //   if (x.getClass() == Foo.class) {
 989   //     Foo foo = (Foo) x;
 990   //     // ... use a ...
 991   //   }
 992   // a CmpPNode could be shared between if_acmpne and checkcast
 993   {
 994     Node* k1 = isa_java_mirror_load(phase, in(1));
 995     Node* k2 = isa_java_mirror_load(phase, in(2));
 996     Node* conk2 = isa_const_java_mirror(phase, in(2));
 997 
 998     if (k1 && (k2 || conk2)) {
 999       Node* lhs = k1;
1000       Node* rhs = (k2 != NULL) ? k2 : conk2;
1001       PhaseIterGVN* igvn = phase->is_IterGVN();
1002       if (igvn != NULL) {
1003         set_req_X(1, lhs, igvn);
1004         set_req_X(2, rhs, igvn);
1005       } else {
1006         set_req(1, lhs);
1007         set_req(2, rhs);
1008       }
1009       return this;
1010     }
1011   }
1012 
1013   // Constant pointer on right?
1014   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
1015   if (t2 == NULL || !t2->klass_is_exact())
1016     return NULL;
1017   // Get the constant klass we are comparing to.
1018   ciKlass* superklass = t2->klass();
1019 
1020   // Now check for LoadKlass on left.
1021   Node* ldk1 = in(1);
1022   if (ldk1->is_DecodeNKlass()) {
1023     ldk1 = ldk1->in(1);
1024     if (ldk1->Opcode() != Op_LoadNKlass )
1025       return NULL;
1026   } else if (ldk1->Opcode() != Op_LoadKlass )
1027     return NULL;
1028   // Take apart the address of the LoadKlass:
1029   Node* adr1 = ldk1->in(MemNode::Address);
1030   intptr_t con2 = 0;
1031   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
1032   if (ldk2 == NULL)
1033     return NULL;
1034   if (con2 == oopDesc::klass_offset_in_bytes()) {
1035     // We are inspecting an object's concrete class.
1036     // Short-circuit the check if the query is abstract.
1037     if (superklass->is_interface() ||
1038         superklass->is_abstract()) {
1039       // Make it come out always false:
1040       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
1041       return this;
1042     }
1043   }
1044 
1045   // Check for a LoadKlass from primary supertype array.
1046   // Any nested loadklass from loadklass+con must be from the p.s. array.
1047   if (ldk2->is_DecodeNKlass()) {
1048     // Keep ldk2 as DecodeN since it could be used in CmpP below.
1049     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
1050       return NULL;
1051   } else if (ldk2->Opcode() != Op_LoadKlass)
1052     return NULL;
1053 
1054   // Verify that we understand the situation
1055   if (con2 != (intptr_t) superklass->super_check_offset())
1056     return NULL;                // Might be element-klass loading from array klass
1057 
1058   // Do not fold the subtype check to an array klass pointer comparison for [V? arrays.
1059   // [V is a subtype of [V? but the klass for [V is not equal to the klass for [V?. Perform a full test.
1060   if (superklass->is_obj_array_klass()) {
1061     ciObjArrayKlass* ak = superklass->as_obj_array_klass();
1062     if (!ak->storage_properties().is_null_free() && ak->element_klass()->is_valuetype()) {
1063       // Do not bypass the klass load from the primary supertype array
1064       return NULL;
1065     }
1066   }
1067 
1068   // If 'superklass' has no subklasses and is not an interface, then we are
1069   // assured that the only input which will pass the type check is
1070   // 'superklass' itself.
1071   //
1072   // We could be more liberal here, and allow the optimization on interfaces
1073   // which have a single implementor.  This would require us to increase the
1074   // expressiveness of the add_dependency() mechanism.
1075   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
1076 
1077   // Object arrays must have their base element have no subtypes
1078   while (superklass->is_obj_array_klass()) {
1079     ciType* elem = superklass->as_obj_array_klass()->element_type();
1080     superklass = elem->as_klass();
1081   }
1082   if (superklass->is_instance_klass()) {
1083     ciInstanceKlass* ik = superklass->as_instance_klass();
1084     if (ik->has_subklass() || ik->is_interface())  return NULL;
1085     // Add a dependency if there is a chance that a subclass will be added later.
1086     if (!ik->is_final()) {
1087       phase->C->dependencies()->assert_leaf_type(ik);
1088     }
1089   }
1090 
1091   // Bypass the dependent load, and compare directly
1092   this->set_req(1,ldk2);
1093 
1094   return this;
1095 }
1096 
1097 //=============================================================================
1098 //------------------------------sub--------------------------------------------
1099 // Simplify an CmpN (compare 2 pointers) node, based on local information.
1100 // If both inputs are constants, compare them.
1101 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
1102   const TypePtr *r0 = t1->make_ptr(); // Handy access
1103   const TypePtr *r1 = t2->make_ptr();
1104 
1105   // Undefined inputs makes for an undefined result
1106   if ((r0 == NULL) || (r1 == NULL) ||
1107       TypePtr::above_centerline(r0->_ptr) ||
1108       TypePtr::above_centerline(r1->_ptr)) {
1109     return Type::TOP;
1110   }
1111   if (r0 == r1 && r0->singleton()) {
1112     // Equal pointer constants (klasses, nulls, etc.)
1113     return TypeInt::CC_EQ;
1114   }
1115 
1116   // See if it is 2 unrelated classes.
1117   const TypeOopPtr* p0 = r0->isa_oopptr();
1118   const TypeOopPtr* p1 = r1->isa_oopptr();
1119   if (p0 && p1) {
1120     ciKlass* klass0 = p0->klass();
1121     bool    xklass0 = p0->klass_is_exact();
1122     ciKlass* klass1 = p1->klass();
1123     bool    xklass1 = p1->klass_is_exact();
1124     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
1125     if (klass0 && klass1 &&
1126         kps != 1 &&             // both or neither are klass pointers
1127         !klass0->is_interface() && // do not trust interfaces
1128         !klass1->is_interface()) {
1129       bool unrelated_classes = false;
1130       // See if neither subclasses the other, or if the class on top
1131       // is precise.  In either of these cases, the compare is known
1132       // to fail if at least one of the pointers is provably not null.
1133       if (klass0->equals(klass1)) { // if types are unequal but klasses are equal
1134         // Do nothing; we know nothing for imprecise types
1135       } else if (klass0->is_subtype_of(klass1)) {
1136         // If klass1's type is PRECISE, then classes are unrelated.
1137         unrelated_classes = xklass1;
1138       } else if (klass1->is_subtype_of(klass0)) {
1139         // If klass0's type is PRECISE, then classes are unrelated.
1140         unrelated_classes = xklass0;
1141       } else {                  // Neither subtypes the other
1142         unrelated_classes = true;
1143       }
1144       if (unrelated_classes) {
1145         // The oops classes are known to be unrelated. If the joined PTRs of
1146         // two oops is not Null and not Bottom, then we are sure that one
1147         // of the two oops is non-null, and the comparison will always fail.
1148         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
1149         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
1150           return TypeInt::CC_GT;
1151         }
1152       }
1153     }
1154   }
1155 
1156   // Known constants can be compared exactly
1157   // Null can be distinguished from any NotNull pointers
1158   // Unknown inputs makes an unknown result
1159   if( r0->singleton() ) {
1160     intptr_t bits0 = r0->get_con();
1161     if( r1->singleton() )
1162       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1163     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1164   } else if( r1->singleton() ) {
1165     intptr_t bits1 = r1->get_con();
1166     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1167   } else
1168     return TypeInt::CC;
1169 }
1170 
1171 //------------------------------Ideal------------------------------------------
1172 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1173   return NULL;
1174 }
1175 
1176 //=============================================================================
1177 //------------------------------Value------------------------------------------
1178 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1179 // If both inputs are constants, compare them.
1180 const Type* CmpFNode::Value(PhaseGVN* phase) const {
1181   const Node* in1 = in(1);
1182   const Node* in2 = in(2);
1183   // Either input is TOP ==> the result is TOP
1184   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1185   if( t1 == Type::TOP ) return Type::TOP;
1186   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1187   if( t2 == Type::TOP ) return Type::TOP;
1188 
1189   // Not constants?  Don't know squat - even if they are the same
1190   // value!  If they are NaN's they compare to LT instead of EQ.
1191   const TypeF *tf1 = t1->isa_float_constant();
1192   const TypeF *tf2 = t2->isa_float_constant();
1193   if( !tf1 || !tf2 ) return TypeInt::CC;
1194 
1195   // This implements the Java bytecode fcmpl, so unordered returns -1.
1196   if( tf1->is_nan() || tf2->is_nan() )
1197     return TypeInt::CC_LT;
1198 
1199   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
1200   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
1201   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
1202   return TypeInt::CC_EQ;
1203 }
1204 
1205 
1206 //=============================================================================
1207 //------------------------------Value------------------------------------------
1208 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
1209 // If both inputs are constants, compare them.
1210 const Type* CmpDNode::Value(PhaseGVN* phase) const {
1211   const Node* in1 = in(1);
1212   const Node* in2 = in(2);
1213   // Either input is TOP ==> the result is TOP
1214   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1215   if( t1 == Type::TOP ) return Type::TOP;
1216   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1217   if( t2 == Type::TOP ) return Type::TOP;
1218 
1219   // Not constants?  Don't know squat - even if they are the same
1220   // value!  If they are NaN's they compare to LT instead of EQ.
1221   const TypeD *td1 = t1->isa_double_constant();
1222   const TypeD *td2 = t2->isa_double_constant();
1223   if( !td1 || !td2 ) return TypeInt::CC;
1224 
1225   // This implements the Java bytecode dcmpl, so unordered returns -1.
1226   if( td1->is_nan() || td2->is_nan() )
1227     return TypeInt::CC_LT;
1228 
1229   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
1230   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
1231   assert( td1->_d == td2->_d, "do not understand FP behavior" );
1232   return TypeInt::CC_EQ;
1233 }
1234 
1235 //------------------------------Ideal------------------------------------------
1236 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
1237   // Check if we can change this to a CmpF and remove a ConvD2F operation.
1238   // Change  (CMPD (F2D (float)) (ConD value))
1239   // To      (CMPF      (float)  (ConF value))
1240   // Valid when 'value' does not lose precision as a float.
1241   // Benefits: eliminates conversion, does not require 24-bit mode
1242 
1243   // NaNs prevent commuting operands.  This transform works regardless of the
1244   // order of ConD and ConvF2D inputs by preserving the original order.
1245   int idx_f2d = 1;              // ConvF2D on left side?
1246   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1247     idx_f2d = 2;                // No, swap to check for reversed args
1248   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1249 
1250   if( ConvertCmpD2CmpF &&
1251       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1252       in(idx_con)->Opcode() == Op_ConD ) {
1253     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1254     double t2_value_as_double = t2->_d;
1255     float  t2_value_as_float  = (float)t2_value_as_double;
1256     if( t2_value_as_double == (double)t2_value_as_float ) {
1257       // Test value can be represented as a float
1258       // Eliminate the conversion to double and create new comparison
1259       Node *new_in1 = in(idx_f2d)->in(1);
1260       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1261       if( idx_f2d != 1 ) {      // Must flip args to match original order
1262         Node *tmp = new_in1;
1263         new_in1 = new_in2;
1264         new_in2 = tmp;
1265       }
1266       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1267         ? new CmpF3Node( new_in1, new_in2 )
1268         : new CmpFNode ( new_in1, new_in2 ) ;
1269       return new_cmp;           // Changed to CmpFNode
1270     }
1271     // Testing value required the precision of a double
1272   }
1273   return NULL;                  // No change
1274 }
1275 
1276 
1277 //=============================================================================
1278 //------------------------------cc2logical-------------------------------------
1279 // Convert a condition code type to a logical type
1280 const Type *BoolTest::cc2logical( const Type *CC ) const {
1281   if( CC == Type::TOP ) return Type::TOP;
1282   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1283   const TypeInt *ti = CC->is_int();
1284   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1285     // Match low order 2 bits
1286     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1287     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1288     return TypeInt::make(tmp);       // Boolean result
1289   }
1290 
1291   if( CC == TypeInt::CC_GE ) {
1292     if( _test == ge ) return TypeInt::ONE;
1293     if( _test == lt ) return TypeInt::ZERO;
1294   }
1295   if( CC == TypeInt::CC_LE ) {
1296     if( _test == le ) return TypeInt::ONE;
1297     if( _test == gt ) return TypeInt::ZERO;
1298   }
1299 
1300   return TypeInt::BOOL;
1301 }
1302 
1303 //------------------------------dump_spec-------------------------------------
1304 // Print special per-node info
1305 void BoolTest::dump_on(outputStream *st) const {
1306   const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
1307   st->print("%s", msg[_test]);
1308 }
1309 
1310 // Returns the logical AND of two tests (or 'never' if both tests can never be true).
1311 // For example, a test for 'le' followed by a test for 'lt' is equivalent with 'lt'.
1312 BoolTest::mask BoolTest::merge(BoolTest other) const {
1313   const mask res[illegal+1][illegal+1] = {
1314     // eq,      gt,      of,      lt,      ne,      le,      nof,     ge,      never,   illegal
1315       {eq,      never,   illegal, never,   never,   eq,      illegal, eq,      never,   illegal},  // eq
1316       {never,   gt,      illegal, never,   gt,      never,   illegal, gt,      never,   illegal},  // gt
1317       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // of
1318       {never,   never,   illegal, lt,      lt,      lt,      illegal, never,   never,   illegal},  // lt
1319       {never,   gt,      illegal, lt,      ne,      lt,      illegal, gt,      never,   illegal},  // ne
1320       {eq,      never,   illegal, lt,      lt,      le,      illegal, eq,      never,   illegal},  // le
1321       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // nof
1322       {eq,      gt,      illegal, never,   gt,      eq,      illegal, ge,      never,   illegal},  // ge
1323       {never,   never,   never,   never,   never,   never,   never,   never,   never,   illegal},  // never
1324       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal}}; // illegal
1325   return res[_test][other._test];
1326 }
1327 
1328 //=============================================================================
1329 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1330 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1331 
1332 //------------------------------operator==-------------------------------------
1333 bool BoolNode::cmp( const Node &n ) const {
1334   const BoolNode *b = (const BoolNode *)&n; // Cast up
1335   return (_test._test == b->_test._test);
1336 }
1337 
1338 //-------------------------------make_predicate--------------------------------
1339 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1340   if (test_value->is_Con())   return test_value;
1341   if (test_value->is_Bool())  return test_value;
1342   if (test_value->is_CMove() &&
1343       test_value->in(CMoveNode::Condition)->is_Bool()) {
1344     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1345     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1346     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1347     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1348       return bol;
1349     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1350       return phase->transform( bol->negate(phase) );
1351     }
1352     // Else fall through.  The CMove gets in the way of the test.
1353     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1354   }
1355   Node* cmp = new CmpINode(test_value, phase->intcon(0));
1356   cmp = phase->transform(cmp);
1357   Node* bol = new BoolNode(cmp, BoolTest::ne);
1358   return phase->transform(bol);
1359 }
1360 
1361 //--------------------------------as_int_value---------------------------------
1362 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1363   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1364   Node* cmov = CMoveNode::make(NULL, this,
1365                                phase->intcon(0), phase->intcon(1),
1366                                TypeInt::BOOL);
1367   return phase->transform(cmov);
1368 }
1369 
1370 //----------------------------------negate-------------------------------------
1371 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1372   return new BoolNode(in(1), _test.negate());
1373 }
1374 
1375 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub
1376 // overflows and we can prove that C is not in the two resulting ranges.
1377 // This optimization is similar to the one performed by CmpUNode::Value().
1378 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, int cmp_op,
1379                           int cmp1_op, const TypeInt* cmp2_type) {
1380   // Only optimize eq/ne integer comparison of add/sub
1381   if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1382      (cmp_op == Op_CmpI) && (cmp1_op == Op_AddI || cmp1_op == Op_SubI)) {
1383     // Skip cases were inputs of add/sub are not integers or of bottom type
1384     const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int();
1385     const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int();
1386     if ((r0 != NULL) && (r0 != TypeInt::INT) &&
1387         (r1 != NULL) && (r1 != TypeInt::INT) &&
1388         (cmp2_type != TypeInt::INT)) {
1389       // Compute exact (long) type range of add/sub result
1390       jlong lo_long = r0->_lo;
1391       jlong hi_long = r0->_hi;
1392       if (cmp1_op == Op_AddI) {
1393         lo_long += r1->_lo;
1394         hi_long += r1->_hi;
1395       } else {
1396         lo_long -= r1->_hi;
1397         hi_long -= r1->_lo;
1398       }
1399       // Check for over-/underflow by casting to integer
1400       int lo_int = (int)lo_long;
1401       int hi_int = (int)hi_long;
1402       bool underflow = lo_long != (jlong)lo_int;
1403       bool overflow  = hi_long != (jlong)hi_int;
1404       if ((underflow != overflow) && (hi_int < lo_int)) {
1405         // Overflow on one boundary, compute resulting type ranges:
1406         // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT]
1407         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
1408         const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w);
1409         const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w);
1410         // Compare second input of cmp to both type ranges
1411         const Type* sub_tr1 = cmp->sub(tr1, cmp2_type);
1412         const Type* sub_tr2 = cmp->sub(tr2, cmp2_type);
1413         if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) {
1414           // The result of the add/sub will never equal cmp2. Replace BoolNode
1415           // by false (0) if it tests for equality and by true (1) otherwise.
1416           return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1);
1417         }
1418       }
1419     }
1420   }
1421   return NULL;
1422 }
1423 
1424 static bool is_counted_loop_cmp(Node *cmp) {
1425   Node *n = cmp->in(1)->in(1);
1426   return n != NULL &&
1427          n->is_Phi() &&
1428          n->in(0) != NULL &&
1429          n->in(0)->is_CountedLoop() &&
1430          n->in(0)->as_CountedLoop()->phi() == n;
1431 }
1432 
1433 //------------------------------Ideal------------------------------------------
1434 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1435   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1436   // This moves the constant to the right.  Helps value-numbering.
1437   Node *cmp = in(1);
1438   if( !cmp->is_Sub() ) return NULL;
1439   int cop = cmp->Opcode();
1440   if( cop == Op_FastLock || cop == Op_FastUnlock) return NULL;
1441   Node *cmp1 = cmp->in(1);
1442   Node *cmp2 = cmp->in(2);
1443   if( !cmp1 ) return NULL;
1444 
1445   if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) {
1446     return NULL;
1447   }
1448 
1449   // Constant on left?
1450   Node *con = cmp1;
1451   uint op2 = cmp2->Opcode();
1452   // Move constants to the right of compare's to canonicalize.
1453   // Do not muck with Opaque1 nodes, as this indicates a loop
1454   // guard that cannot change shape.
1455   if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 &&
1456       // Because of NaN's, CmpD and CmpF are not commutative
1457       cop != Op_CmpD && cop != Op_CmpF &&
1458       // Protect against swapping inputs to a compare when it is used by a
1459       // counted loop exit, which requires maintaining the loop-limit as in(2)
1460       !is_counted_loop_exit_test() ) {
1461     // Ok, commute the constant to the right of the cmp node.
1462     // Clone the Node, getting a new Node of the same class
1463     cmp = cmp->clone();
1464     // Swap inputs to the clone
1465     cmp->swap_edges(1, 2);
1466     cmp = phase->transform( cmp );
1467     return new BoolNode( cmp, _test.commute() );
1468   }
1469 
1470   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1471   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1472   // test instead.
1473   int cmp1_op = cmp1->Opcode();
1474   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1475   if (cmp2_type == NULL)  return NULL;
1476   Node* j_xor = cmp1;
1477   if( cmp2_type == TypeInt::ZERO &&
1478       cmp1_op == Op_XorI &&
1479       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1480       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1481       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1482       (_test._test == BoolTest::eq ||
1483        _test._test == BoolTest::ne) ) {
1484     Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2));
1485     return new BoolNode( ncmp, _test.negate() );
1486   }
1487 
1488   // Change ((x & m) u<= m) or ((m & x) u<= m) to always true
1489   // Same with ((x & m) u< m+1) and ((m & x) u< m+1)
1490   if (cop == Op_CmpU &&
1491       cmp1_op == Op_AndI) {
1492     Node* bound = NULL;
1493     if (_test._test == BoolTest::le) {
1494       bound = cmp2;
1495     } else if (_test._test == BoolTest::lt &&
1496                cmp2->Opcode() == Op_AddI &&
1497                cmp2->in(2)->find_int_con(0) == 1) {
1498       bound = cmp2->in(1);
1499     }
1500     if (cmp1->in(2) == bound || cmp1->in(1) == bound) {
1501       return ConINode::make(1);
1502     }
1503   }
1504 
1505   // Change ((x & (m - 1)) u< m) into (m > 0)
1506   // This is the off-by-one variant of the above
1507   if (cop == Op_CmpU &&
1508       _test._test == BoolTest::lt &&
1509       cmp1_op == Op_AndI) {
1510     Node* l = cmp1->in(1);
1511     Node* r = cmp1->in(2);
1512     for (int repeat = 0; repeat < 2; repeat++) {
1513       bool match = r->Opcode() == Op_AddI && r->in(2)->find_int_con(0) == -1 &&
1514                    r->in(1) == cmp2;
1515       if (match) {
1516         // arraylength known to be non-negative, so a (arraylength != 0) is sufficient,
1517         // but to be compatible with the array range check pattern, use (arraylength u> 0)
1518         Node* ncmp = cmp2->Opcode() == Op_LoadRange
1519                      ? phase->transform(new CmpUNode(cmp2, phase->intcon(0)))
1520                      : phase->transform(new CmpINode(cmp2, phase->intcon(0)));
1521         return new BoolNode(ncmp, BoolTest::gt);
1522       } else {
1523         // commute and try again
1524         l = cmp1->in(2);
1525         r = cmp1->in(1);
1526       }
1527     }
1528   }
1529 
1530   // Change x u< 1 or x u<= 0 to x == 0
1531   if (cop == Op_CmpU &&
1532       cmp1_op != Op_LoadRange &&
1533       ((_test._test == BoolTest::lt &&
1534         cmp2->find_int_con(-1) == 1) ||
1535        (_test._test == BoolTest::le &&
1536         cmp2->find_int_con(-1) == 0))) {
1537     Node* ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1538     return new BoolNode(ncmp, BoolTest::eq);
1539   }
1540 
1541   // Change (arraylength <= 0) or (arraylength == 0)
1542   //   into (arraylength u<= 0)
1543   // Also change (arraylength != 0) into (arraylength u> 0)
1544   // The latter version matches the code pattern generated for
1545   // array range checks, which will more likely be optimized later.
1546   if (cop == Op_CmpI &&
1547       cmp1_op == Op_LoadRange &&
1548       cmp2->find_int_con(-1) == 0) {
1549     if (_test._test == BoolTest::le || _test._test == BoolTest::eq) {
1550       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1551       return new BoolNode(ncmp, BoolTest::le);
1552     } else if (_test._test == BoolTest::ne) {
1553       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1554       return new BoolNode(ncmp, BoolTest::gt);
1555     }
1556   }
1557 
1558   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1559   // This is a standard idiom for branching on a boolean value.
1560   Node *c2b = cmp1;
1561   if( cmp2_type == TypeInt::ZERO &&
1562       cmp1_op == Op_Conv2B &&
1563       (_test._test == BoolTest::eq ||
1564        _test._test == BoolTest::ne) ) {
1565     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1566        ? (Node*)new CmpINode(c2b->in(1),cmp2)
1567        : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1568     );
1569     return new BoolNode( ncmp, _test._test );
1570   }
1571 
1572   // Comparing a SubI against a zero is equal to comparing the SubI
1573   // arguments directly.  This only works for eq and ne comparisons
1574   // due to possible integer overflow.
1575   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1576         (cop == Op_CmpI) &&
1577         (cmp1_op == Op_SubI) &&
1578         ( cmp2_type == TypeInt::ZERO ) ) {
1579     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2)));
1580     return new BoolNode( ncmp, _test._test );
1581   }
1582 
1583   // Same as above but with and AddI of a constant
1584   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1585       cop == Op_CmpI &&
1586       cmp1_op == Op_AddI &&
1587       cmp1->in(2) != NULL &&
1588       phase->type(cmp1->in(2))->isa_int() &&
1589       phase->type(cmp1->in(2))->is_int()->is_con() &&
1590       cmp2_type == TypeInt::ZERO &&
1591       !is_counted_loop_cmp(cmp) // modifying the exit test of a counted loop messes the counted loop shape
1592       ) {
1593     const TypeInt* cmp1_in2 = phase->type(cmp1->in(2))->is_int();
1594     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),phase->intcon(-cmp1_in2->_hi)));
1595     return new BoolNode( ncmp, _test._test );
1596   }
1597 
1598   // Change "bool eq/ne (cmp (phi (X -X) 0))" into "bool eq/ne (cmp X 0)"
1599   // since zero check of conditional negation of an integer is equal to
1600   // zero check of the integer directly.
1601   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1602       (cop == Op_CmpI) &&
1603       (cmp2_type == TypeInt::ZERO) &&
1604       (cmp1_op == Op_Phi)) {
1605     // There should be a diamond phi with true path at index 1 or 2
1606     PhiNode *phi = cmp1->as_Phi();
1607     int idx_true = phi->is_diamond_phi();
1608     if (idx_true != 0) {
1609       // True input is in(idx_true) while false input is in(3 - idx_true)
1610       Node *tin = phi->in(idx_true);
1611       Node *fin = phi->in(3 - idx_true);
1612       if ((tin->Opcode() == Op_SubI) &&
1613           (phase->type(tin->in(1)) == TypeInt::ZERO) &&
1614           (tin->in(2) == fin)) {
1615         // Found conditional negation at true path, create a new CmpINode without that
1616         Node *ncmp = phase->transform(new CmpINode(fin, cmp2));
1617         return new BoolNode(ncmp, _test._test);
1618       }
1619       if ((fin->Opcode() == Op_SubI) &&
1620           (phase->type(fin->in(1)) == TypeInt::ZERO) &&
1621           (fin->in(2) == tin)) {
1622         // Found conditional negation at false path, create a new CmpINode without that
1623         Node *ncmp = phase->transform(new CmpINode(tin, cmp2));
1624         return new BoolNode(ncmp, _test._test);
1625       }
1626     }
1627   }
1628 
1629   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1630   // most general case because negating 0x80000000 does nothing.  Needed for
1631   // the CmpF3/SubI/CmpI idiom.
1632   if( cop == Op_CmpI &&
1633       cmp1_op == Op_SubI &&
1634       cmp2_type == TypeInt::ZERO &&
1635       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1636       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1637     Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2));
1638     return new BoolNode( ncmp, _test.commute() );
1639   }
1640 
1641   // Try to optimize signed integer comparison
1642   return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type);
1643 
1644   //  The transformation below is not valid for either signed or unsigned
1645   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1646   //  This transformation can be resurrected when we are able to
1647   //  make inferences about the range of values being subtracted from
1648   //  (or added to) relative to the wraparound point.
1649   //
1650   //    // Remove +/-1's if possible.
1651   //    // "X <= Y-1" becomes "X <  Y"
1652   //    // "X+1 <= Y" becomes "X <  Y"
1653   //    // "X <  Y+1" becomes "X <= Y"
1654   //    // "X-1 <  Y" becomes "X <= Y"
1655   //    // Do not this to compares off of the counted-loop-end.  These guys are
1656   //    // checking the trip counter and they want to use the post-incremented
1657   //    // counter.  If they use the PRE-incremented counter, then the counter has
1658   //    // to be incremented in a private block on a loop backedge.
1659   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1660   //      return NULL;
1661   //  #ifndef PRODUCT
1662   //    // Do not do this in a wash GVN pass during verification.
1663   //    // Gets triggered by too many simple optimizations to be bothered with
1664   //    // re-trying it again and again.
1665   //    if( !phase->allow_progress() ) return NULL;
1666   //  #endif
1667   //    // Not valid for unsigned compare because of corner cases in involving zero.
1668   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1669   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1670   //    // "0 <=u Y" is always true).
1671   //    if( cmp->Opcode() == Op_CmpU ) return NULL;
1672   //    int cmp2_op = cmp2->Opcode();
1673   //    if( _test._test == BoolTest::le ) {
1674   //      if( cmp1_op == Op_AddI &&
1675   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1676   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1677   //      else if( cmp2_op == Op_AddI &&
1678   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1679   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1680   //    } else if( _test._test == BoolTest::lt ) {
1681   //      if( cmp1_op == Op_AddI &&
1682   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1683   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1684   //      else if( cmp2_op == Op_AddI &&
1685   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1686   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1687   //    }
1688 }
1689 
1690 //------------------------------Value------------------------------------------
1691 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
1692 // based on local information.   If the input is constant, do it.
1693 const Type* BoolNode::Value(PhaseGVN* phase) const {
1694   return _test.cc2logical( phase->type( in(1) ) );
1695 }
1696 
1697 #ifndef PRODUCT
1698 //------------------------------dump_spec--------------------------------------
1699 // Dump special per-node info
1700 void BoolNode::dump_spec(outputStream *st) const {
1701   st->print("[");
1702   _test.dump_on(st);
1703   st->print("]");
1704 }
1705 
1706 //-------------------------------related---------------------------------------
1707 // A BoolNode's related nodes are all of its data inputs, and all of its
1708 // outputs until control nodes are hit, which are included. In compact
1709 // representation, inputs till level 3 and immediate outputs are included.
1710 void BoolNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
1711   if (compact) {
1712     this->collect_nodes(in_rel, 3, false, true);
1713     this->collect_nodes(out_rel, -1, false, false);
1714   } else {
1715     this->collect_nodes_in_all_data(in_rel, false);
1716     this->collect_nodes_out_all_ctrl_boundary(out_rel);
1717   }
1718 }
1719 #endif
1720 
1721 //----------------------is_counted_loop_exit_test------------------------------
1722 // Returns true if node is used by a counted loop node.
1723 bool BoolNode::is_counted_loop_exit_test() {
1724   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
1725     Node* use = fast_out(i);
1726     if (use->is_CountedLoopEnd()) {
1727       return true;
1728     }
1729   }
1730   return false;
1731 }
1732 
1733 //=============================================================================
1734 //------------------------------Value------------------------------------------
1735 // Compute sqrt
1736 const Type* SqrtDNode::Value(PhaseGVN* phase) const {
1737   const Type *t1 = phase->type( in(1) );
1738   if( t1 == Type::TOP ) return Type::TOP;
1739   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1740   double d = t1->getd();
1741   if( d < 0.0 ) return Type::DOUBLE;
1742   return TypeD::make( sqrt( d ) );
1743 }
1744 
1745 const Type* SqrtFNode::Value(PhaseGVN* phase) const {
1746   const Type *t1 = phase->type( in(1) );
1747   if( t1 == Type::TOP ) return Type::TOP;
1748   if( t1->base() != Type::FloatCon ) return Type::FLOAT;
1749   float f = t1->getf();
1750   if( f < 0.0f ) return Type::FLOAT;
1751   return TypeF::make( (float)sqrt( (double)f ) );
1752 }