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 
 727 //=============================================================================
 728 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 729 // If both inputs are constants, compare them.
 730 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 731   const TypeLong *r0 = t1->is_long(); // Handy access
 732   const TypeLong *r1 = t2->is_long();
 733 
 734   if( r0->_hi < r1->_lo )       // Range is always low?
 735     return TypeInt::CC_LT;
 736   else if( r0->_lo > r1->_hi )  // Range is always high?
 737     return TypeInt::CC_GT;
 738 
 739   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 740     assert(r0->get_con() == r1->get_con(), "must be equal");
 741     return TypeInt::CC_EQ;      // Equal results.
 742   } else if( r0->_hi == r1->_lo ) // Range is never high?
 743     return TypeInt::CC_LE;
 744   else if( r0->_lo == r1->_hi ) // Range is never low?
 745     return TypeInt::CC_GE;
 746   return TypeInt::CC;           // else use worst case results
 747 }
 748 
 749 
 750 // Simplify a CmpUL (compare 2 unsigned longs) node, based on local information.
 751 // If both inputs are constants, compare them.
 752 const Type* CmpULNode::sub(const Type* t1, const Type* t2) const {
 753   assert(!t1->isa_ptr(), "obsolete usage of CmpUL");
 754 
 755   // comparing two unsigned longs
 756   const TypeLong* r0 = t1->is_long();   // Handy access
 757   const TypeLong* r1 = t2->is_long();
 758 
 759   // Current installed version
 760   // Compare ranges for non-overlap
 761   julong lo0 = r0->_lo;
 762   julong hi0 = r0->_hi;
 763   julong lo1 = r1->_lo;
 764   julong hi1 = r1->_hi;
 765 
 766   // If either one has both negative and positive values,
 767   // it therefore contains both 0 and -1, and since [0..-1] is the
 768   // full unsigned range, the type must act as an unsigned bottom.
 769   bool bot0 = ((jlong)(lo0 ^ hi0) < 0);
 770   bool bot1 = ((jlong)(lo1 ^ hi1) < 0);
 771 
 772   if (bot0 || bot1) {
 773     // All unsigned values are LE -1 and GE 0.
 774     if (lo0 == 0 && hi0 == 0) {
 775       return TypeInt::CC_LE;            //   0 <= bot
 776     } else if ((jlong)lo0 == -1 && (jlong)hi0 == -1) {
 777       return TypeInt::CC_GE;            // -1 >= bot
 778     } else if (lo1 == 0 && hi1 == 0) {
 779       return TypeInt::CC_GE;            // bot >= 0
 780     } else if ((jlong)lo1 == -1 && (jlong)hi1 == -1) {
 781       return TypeInt::CC_LE;            // bot <= -1
 782     }
 783   } else {
 784     // We can use ranges of the form [lo..hi] if signs are the same.
 785     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 786     // results are reversed, '-' > '+' for unsigned compare
 787     if (hi0 < lo1) {
 788       return TypeInt::CC_LT;            // smaller
 789     } else if (lo0 > hi1) {
 790       return TypeInt::CC_GT;            // greater
 791     } else if (hi0 == lo1 && lo0 == hi1) {
 792       return TypeInt::CC_EQ;            // Equal results
 793     } else if (lo0 >= hi1) {
 794       return TypeInt::CC_GE;
 795     } else if (hi0 <= lo1) {
 796       return TypeInt::CC_LE;
 797     }
 798   }
 799 
 800   return TypeInt::CC;                   // else use worst case results
 801 }
 802 
 803 //=============================================================================
 804 //------------------------------sub--------------------------------------------
 805 // Simplify an CmpP (compare 2 pointers) node, based on local information.
 806 // If both inputs are constants, compare them.
 807 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
 808   const TypePtr *r0 = t1->is_ptr(); // Handy access
 809   const TypePtr *r1 = t2->is_ptr();
 810 
 811   // Undefined inputs makes for an undefined result
 812   if( TypePtr::above_centerline(r0->_ptr) ||
 813       TypePtr::above_centerline(r1->_ptr) )
 814     return Type::TOP;
 815 
 816   if (r0 == r1 && r0->singleton()) {
 817     // Equal pointer constants (klasses, nulls, etc.)
 818     return TypeInt::CC_EQ;
 819   }
 820 
 821   // See if it is 2 unrelated classes.
 822   const TypeOopPtr* p0 = r0->isa_oopptr();
 823   const TypeOopPtr* p1 = r1->isa_oopptr();
 824   if (p0 && p1) {
 825     Node* in1 = in(1)->uncast();
 826     Node* in2 = in(2)->uncast();
 827     AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
 828     AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
 829     if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
 830       return TypeInt::CC_GT;  // different pointers
 831     }
 832     ciKlass* klass0 = p0->klass();
 833     bool    xklass0 = p0->klass_is_exact();
 834     ciKlass* klass1 = p1->klass();
 835     bool    xklass1 = p1->klass_is_exact();
 836     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 837     if (klass0 && klass1 &&
 838         kps != 1 &&             // both or neither are klass pointers
 839         klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
 840         klass1->is_loaded() && !klass1->is_interface() &&
 841         (!klass0->is_obj_array_klass() ||
 842          !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
 843         (!klass1->is_obj_array_klass() ||
 844          !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
 845       bool unrelated_classes = false;
 846       // See if neither subclasses the other, or if the class on top
 847       // is precise.  In either of these cases, the compare is known
 848       // to fail if at least one of the pointers is provably not null.
 849       if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
 850         // Do nothing; we know nothing for imprecise types
 851       } else if (klass0->is_subtype_of(klass1)) {
 852         // If klass1's type is PRECISE, then classes are unrelated.
 853         unrelated_classes = xklass1;
 854       } else if (klass1->is_subtype_of(klass0)) {
 855         // If klass0's type is PRECISE, then classes are unrelated.
 856         unrelated_classes = xklass0;
 857       } else {                  // Neither subtypes the other
 858         unrelated_classes = true;
 859       }
 860       if (unrelated_classes) {
 861         // The oops classes are known to be unrelated. If the joined PTRs of
 862         // two oops is not Null and not Bottom, then we are sure that one
 863         // of the two oops is non-null, and the comparison will always fail.
 864         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 865         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 866           return TypeInt::CC_GT;
 867         }
 868       }
 869     }
 870   }
 871 
 872   // Known constants can be compared exactly
 873   // Null can be distinguished from any NotNull pointers
 874   // Unknown inputs makes an unknown result
 875   if( r0->singleton() ) {
 876     intptr_t bits0 = r0->get_con();
 877     if( r1->singleton() )
 878       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 879     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 880   } else if( r1->singleton() ) {
 881     intptr_t bits1 = r1->get_con();
 882     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 883   } else
 884     return TypeInt::CC;
 885 }
 886 
 887 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
 888   // Return the klass node for (indirect load from OopHandle)
 889   //   LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
 890   //   or NULL if not matching.
 891   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 892     n = bs->step_over_gc_barrier(n);
 893 
 894   if (n->Opcode() != Op_LoadP) return NULL;
 895 
 896   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 897   if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;
 898 
 899   Node* adr = n->in(MemNode::Address);
 900   // First load from OopHandle: ((OopHandle)mirror)->resolve(); may need barrier.
 901   if (adr->Opcode() != Op_LoadP || !phase->type(adr)->isa_rawptr()) return NULL;
 902   adr = adr->in(MemNode::Address);
 903 
 904   intptr_t off = 0;
 905   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
 906   if (k == NULL)  return NULL;
 907   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
 908   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL;
 909 
 910   // We've found the klass node of a Java mirror load.
 911   return k;
 912 }
 913 
 914 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
 915   // for ConP(Foo.class) return ConP(Foo.klass)
 916   // otherwise return NULL
 917   if (!n->is_Con()) return NULL;
 918 
 919   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 920   if (!tp) return NULL;
 921 
 922   ciType* mirror_type = tp->java_mirror_type();
 923   // TypeInstPtr::java_mirror_type() returns non-NULL for compile-
 924   // time Class constants only.
 925   if (!mirror_type) return NULL;
 926 
 927   // x.getClass() == int.class can never be true (for all primitive types)
 928   // Return a ConP(NULL) node for this case.
 929   if (mirror_type->is_classless()) {
 930     return phase->makecon(TypePtr::NULL_PTR);
 931   }
 932 
 933   // return the ConP(Foo.klass)
 934   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
 935   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass()));
 936 }
 937 
 938 //------------------------------Ideal------------------------------------------
 939 // Normalize comparisons between Java mirror loads to compare the klass instead.
 940 //
 941 // Also check for the case of comparing an unknown klass loaded from the primary
 942 // super-type array vs a known klass with no subtypes.  This amounts to
 943 // checking to see an unknown klass subtypes a known klass with no subtypes;
 944 // this only happens on an exact match.  We can shorten this test by 1 load.
 945 Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 946   // Normalize comparisons between Java mirrors into comparisons of the low-
 947   // level klass, where a dependent load could be shortened.
 948   //
 949   // The new pattern has a nice effect of matching the same pattern used in the
 950   // fast path of instanceof/checkcast/Class.isInstance(), which allows
 951   // redundant exact type check be optimized away by GVN.
 952   // For example, in
 953   //   if (x.getClass() == Foo.class) {
 954   //     Foo foo = (Foo) x;
 955   //     // ... use a ...
 956   //   }
 957   // a CmpPNode could be shared between if_acmpne and checkcast
 958   {
 959     Node* k1 = isa_java_mirror_load(phase, in(1));
 960     Node* k2 = isa_java_mirror_load(phase, in(2));
 961     Node* conk2 = isa_const_java_mirror(phase, in(2));
 962 
 963     if (k1 && (k2 || conk2)) {
 964       Node* lhs = k1;
 965       Node* rhs = (k2 != NULL) ? k2 : conk2;
 966       PhaseIterGVN* igvn = phase->is_IterGVN();
 967       if (igvn != NULL) {
 968         set_req_X(1, lhs, igvn);
 969         set_req_X(2, rhs, igvn);
 970       } else {
 971         set_req(1, lhs);
 972         set_req(2, rhs);
 973       }
 974       return this;
 975     }
 976   }
 977 
 978   // Constant pointer on right?
 979   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
 980   if (t2 == NULL || !t2->klass_is_exact())
 981     return NULL;
 982   // Get the constant klass we are comparing to.
 983   ciKlass* superklass = t2->klass();
 984 
 985   // Now check for LoadKlass on left.
 986   Node* ldk1 = in(1);
 987   if (ldk1->is_DecodeNKlass()) {
 988     ldk1 = ldk1->in(1);
 989     if (ldk1->Opcode() != Op_LoadNKlass )
 990       return NULL;
 991   } else if (ldk1->Opcode() != Op_LoadKlass )
 992     return NULL;
 993   // Take apart the address of the LoadKlass:
 994   Node* adr1 = ldk1->in(MemNode::Address);
 995   intptr_t con2 = 0;
 996   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
 997   if (ldk2 == NULL)
 998     return NULL;
 999   if (con2 == oopDesc::klass_offset_in_bytes()) {
1000     // We are inspecting an object's concrete class.
1001     // Short-circuit the check if the query is abstract.
1002     if (superklass->is_interface() ||
1003         superklass->is_abstract()) {
1004       // Make it come out always false:
1005       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
1006       return this;
1007     }
1008   }
1009 
1010   // Check for a LoadKlass from primary supertype array.
1011   // Any nested loadklass from loadklass+con must be from the p.s. array.
1012   if (ldk2->is_DecodeNKlass()) {
1013     // Keep ldk2 as DecodeN since it could be used in CmpP below.
1014     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
1015       return NULL;
1016   } else if (ldk2->Opcode() != Op_LoadKlass)
1017     return NULL;
1018 
1019   // Verify that we understand the situation
1020   if (con2 != (intptr_t) superklass->super_check_offset())
1021     return NULL;                // Might be element-klass loading from array klass
1022 
1023   // If 'superklass' has no subklasses and is not an interface, then we are
1024   // assured that the only input which will pass the type check is
1025   // 'superklass' itself.
1026   //
1027   // We could be more liberal here, and allow the optimization on interfaces
1028   // which have a single implementor.  This would require us to increase the
1029   // expressiveness of the add_dependency() mechanism.
1030   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
1031 
1032   // Object arrays must have their base element have no subtypes
1033   while (superklass->is_obj_array_klass()) {
1034     ciType* elem = superklass->as_obj_array_klass()->element_type();
1035     superklass = elem->as_klass();
1036   }
1037   if (superklass->is_instance_klass()) {
1038     ciInstanceKlass* ik = superklass->as_instance_klass();
1039     if (ik->has_subklass() || ik->is_interface())  return NULL;
1040     // Add a dependency if there is a chance that a subclass will be added later.
1041     if (!ik->is_final()) {
1042       phase->C->dependencies()->assert_leaf_type(ik);
1043     }
1044   }
1045 
1046   // Bypass the dependent load, and compare directly
1047   this->set_req(1,ldk2);
1048 
1049   return this;
1050 }
1051 
1052 //=============================================================================
1053 //------------------------------sub--------------------------------------------
1054 // Simplify an CmpN (compare 2 pointers) node, based on local information.
1055 // If both inputs are constants, compare them.
1056 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
1057   const TypePtr *r0 = t1->make_ptr(); // Handy access
1058   const TypePtr *r1 = t2->make_ptr();
1059 
1060   // Undefined inputs makes for an undefined result
1061   if ((r0 == NULL) || (r1 == NULL) ||
1062       TypePtr::above_centerline(r0->_ptr) ||
1063       TypePtr::above_centerline(r1->_ptr)) {
1064     return Type::TOP;
1065   }
1066   if (r0 == r1 && r0->singleton()) {
1067     // Equal pointer constants (klasses, nulls, etc.)
1068     return TypeInt::CC_EQ;
1069   }
1070 
1071   // See if it is 2 unrelated classes.
1072   const TypeOopPtr* p0 = r0->isa_oopptr();
1073   const TypeOopPtr* p1 = r1->isa_oopptr();
1074   if (p0 && p1) {
1075     ciKlass* klass0 = p0->klass();
1076     bool    xklass0 = p0->klass_is_exact();
1077     ciKlass* klass1 = p1->klass();
1078     bool    xklass1 = p1->klass_is_exact();
1079     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
1080     if (klass0 && klass1 &&
1081         kps != 1 &&             // both or neither are klass pointers
1082         !klass0->is_interface() && // do not trust interfaces
1083         !klass1->is_interface()) {
1084       bool unrelated_classes = false;
1085       // See if neither subclasses the other, or if the class on top
1086       // is precise.  In either of these cases, the compare is known
1087       // to fail if at least one of the pointers is provably not null.
1088       if (klass0->equals(klass1)) { // if types are unequal but klasses are equal
1089         // Do nothing; we know nothing for imprecise types
1090       } else if (klass0->is_subtype_of(klass1)) {
1091         // If klass1's type is PRECISE, then classes are unrelated.
1092         unrelated_classes = xklass1;
1093       } else if (klass1->is_subtype_of(klass0)) {
1094         // If klass0's type is PRECISE, then classes are unrelated.
1095         unrelated_classes = xklass0;
1096       } else {                  // Neither subtypes the other
1097         unrelated_classes = true;
1098       }
1099       if (unrelated_classes) {
1100         // The oops classes are known to be unrelated. If the joined PTRs of
1101         // two oops is not Null and not Bottom, then we are sure that one
1102         // of the two oops is non-null, and the comparison will always fail.
1103         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
1104         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
1105           return TypeInt::CC_GT;
1106         }
1107       }
1108     }
1109   }
1110 
1111   // Known constants can be compared exactly
1112   // Null can be distinguished from any NotNull pointers
1113   // Unknown inputs makes an unknown result
1114   if( r0->singleton() ) {
1115     intptr_t bits0 = r0->get_con();
1116     if( r1->singleton() )
1117       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1118     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1119   } else if( r1->singleton() ) {
1120     intptr_t bits1 = r1->get_con();
1121     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1122   } else
1123     return TypeInt::CC;
1124 }
1125 
1126 //------------------------------Ideal------------------------------------------
1127 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1128   return NULL;
1129 }
1130 
1131 //=============================================================================
1132 //------------------------------Value------------------------------------------
1133 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1134 // If both inputs are constants, compare them.
1135 const Type* CmpFNode::Value(PhaseGVN* phase) const {
1136   const Node* in1 = in(1);
1137   const Node* in2 = in(2);
1138   // Either input is TOP ==> the result is TOP
1139   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1140   if( t1 == Type::TOP ) return Type::TOP;
1141   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1142   if( t2 == Type::TOP ) return Type::TOP;
1143 
1144   // Not constants?  Don't know squat - even if they are the same
1145   // value!  If they are NaN's they compare to LT instead of EQ.
1146   const TypeF *tf1 = t1->isa_float_constant();
1147   const TypeF *tf2 = t2->isa_float_constant();
1148   if( !tf1 || !tf2 ) return TypeInt::CC;
1149 
1150   // This implements the Java bytecode fcmpl, so unordered returns -1.
1151   if( tf1->is_nan() || tf2->is_nan() )
1152     return TypeInt::CC_LT;
1153 
1154   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
1155   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
1156   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
1157   return TypeInt::CC_EQ;
1158 }
1159 
1160 
1161 //=============================================================================
1162 //------------------------------Value------------------------------------------
1163 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
1164 // If both inputs are constants, compare them.
1165 const Type* CmpDNode::Value(PhaseGVN* phase) const {
1166   const Node* in1 = in(1);
1167   const Node* in2 = in(2);
1168   // Either input is TOP ==> the result is TOP
1169   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1170   if( t1 == Type::TOP ) return Type::TOP;
1171   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1172   if( t2 == Type::TOP ) return Type::TOP;
1173 
1174   // Not constants?  Don't know squat - even if they are the same
1175   // value!  If they are NaN's they compare to LT instead of EQ.
1176   const TypeD *td1 = t1->isa_double_constant();
1177   const TypeD *td2 = t2->isa_double_constant();
1178   if( !td1 || !td2 ) return TypeInt::CC;
1179 
1180   // This implements the Java bytecode dcmpl, so unordered returns -1.
1181   if( td1->is_nan() || td2->is_nan() )
1182     return TypeInt::CC_LT;
1183 
1184   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
1185   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
1186   assert( td1->_d == td2->_d, "do not understand FP behavior" );
1187   return TypeInt::CC_EQ;
1188 }
1189 
1190 //------------------------------Ideal------------------------------------------
1191 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
1192   // Check if we can change this to a CmpF and remove a ConvD2F operation.
1193   // Change  (CMPD (F2D (float)) (ConD value))
1194   // To      (CMPF      (float)  (ConF value))
1195   // Valid when 'value' does not lose precision as a float.
1196   // Benefits: eliminates conversion, does not require 24-bit mode
1197 
1198   // NaNs prevent commuting operands.  This transform works regardless of the
1199   // order of ConD and ConvF2D inputs by preserving the original order.
1200   int idx_f2d = 1;              // ConvF2D on left side?
1201   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1202     idx_f2d = 2;                // No, swap to check for reversed args
1203   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1204 
1205   if( ConvertCmpD2CmpF &&
1206       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1207       in(idx_con)->Opcode() == Op_ConD ) {
1208     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1209     double t2_value_as_double = t2->_d;
1210     float  t2_value_as_float  = (float)t2_value_as_double;
1211     if( t2_value_as_double == (double)t2_value_as_float ) {
1212       // Test value can be represented as a float
1213       // Eliminate the conversion to double and create new comparison
1214       Node *new_in1 = in(idx_f2d)->in(1);
1215       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1216       if( idx_f2d != 1 ) {      // Must flip args to match original order
1217         Node *tmp = new_in1;
1218         new_in1 = new_in2;
1219         new_in2 = tmp;
1220       }
1221       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1222         ? new CmpF3Node( new_in1, new_in2 )
1223         : new CmpFNode ( new_in1, new_in2 ) ;
1224       return new_cmp;           // Changed to CmpFNode
1225     }
1226     // Testing value required the precision of a double
1227   }
1228   return NULL;                  // No change
1229 }
1230 
1231 
1232 //=============================================================================
1233 //------------------------------cc2logical-------------------------------------
1234 // Convert a condition code type to a logical type
1235 const Type *BoolTest::cc2logical( const Type *CC ) const {
1236   if( CC == Type::TOP ) return Type::TOP;
1237   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1238   const TypeInt *ti = CC->is_int();
1239   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1240     // Match low order 2 bits
1241     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1242     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1243     return TypeInt::make(tmp);       // Boolean result
1244   }
1245 
1246   if( CC == TypeInt::CC_GE ) {
1247     if( _test == ge ) return TypeInt::ONE;
1248     if( _test == lt ) return TypeInt::ZERO;
1249   }
1250   if( CC == TypeInt::CC_LE ) {
1251     if( _test == le ) return TypeInt::ONE;
1252     if( _test == gt ) return TypeInt::ZERO;
1253   }
1254 
1255   return TypeInt::BOOL;
1256 }
1257 
1258 //------------------------------dump_spec-------------------------------------
1259 // Print special per-node info
1260 void BoolTest::dump_on(outputStream *st) const {
1261   const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
1262   st->print("%s", msg[_test]);
1263 }
1264 
1265 // Returns the logical AND of two tests (or 'never' if both tests can never be true).
1266 // For example, a test for 'le' followed by a test for 'lt' is equivalent with 'lt'.
1267 BoolTest::mask BoolTest::merge(BoolTest other) const {
1268   const mask res[illegal+1][illegal+1] = {
1269     // eq,      gt,      of,      lt,      ne,      le,      nof,     ge,      never,   illegal
1270       {eq,      never,   illegal, never,   never,   eq,      illegal, eq,      never,   illegal},  // eq
1271       {never,   gt,      illegal, never,   gt,      never,   illegal, gt,      never,   illegal},  // gt
1272       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // of
1273       {never,   never,   illegal, lt,      lt,      lt,      illegal, never,   never,   illegal},  // lt
1274       {never,   gt,      illegal, lt,      ne,      lt,      illegal, gt,      never,   illegal},  // ne
1275       {eq,      never,   illegal, lt,      lt,      le,      illegal, eq,      never,   illegal},  // le
1276       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // nof
1277       {eq,      gt,      illegal, never,   gt,      eq,      illegal, ge,      never,   illegal},  // ge
1278       {never,   never,   never,   never,   never,   never,   never,   never,   never,   illegal},  // never
1279       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal}}; // illegal
1280   return res[_test][other._test];
1281 }
1282 
1283 //=============================================================================
1284 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1285 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1286 
1287 //------------------------------operator==-------------------------------------
1288 bool BoolNode::cmp( const Node &n ) const {
1289   const BoolNode *b = (const BoolNode *)&n; // Cast up
1290   return (_test._test == b->_test._test);
1291 }
1292 
1293 //-------------------------------make_predicate--------------------------------
1294 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1295   if (test_value->is_Con())   return test_value;
1296   if (test_value->is_Bool())  return test_value;
1297   if (test_value->is_CMove() &&
1298       test_value->in(CMoveNode::Condition)->is_Bool()) {
1299     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1300     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1301     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1302     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1303       return bol;
1304     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1305       return phase->transform( bol->negate(phase) );
1306     }
1307     // Else fall through.  The CMove gets in the way of the test.
1308     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1309   }
1310   Node* cmp = new CmpINode(test_value, phase->intcon(0));
1311   cmp = phase->transform(cmp);
1312   Node* bol = new BoolNode(cmp, BoolTest::ne);
1313   return phase->transform(bol);
1314 }
1315 
1316 //--------------------------------as_int_value---------------------------------
1317 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1318   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1319   Node* cmov = CMoveNode::make(NULL, this,
1320                                phase->intcon(0), phase->intcon(1),
1321                                TypeInt::BOOL);
1322   return phase->transform(cmov);
1323 }
1324 
1325 //----------------------------------negate-------------------------------------
1326 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1327   return new BoolNode(in(1), _test.negate());
1328 }
1329 
1330 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub
1331 // overflows and we can prove that C is not in the two resulting ranges.
1332 // This optimization is similar to the one performed by CmpUNode::Value().
1333 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, int cmp_op,
1334                           int cmp1_op, const TypeInt* cmp2_type) {
1335   // Only optimize eq/ne integer comparison of add/sub
1336   if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1337      (cmp_op == Op_CmpI) && (cmp1_op == Op_AddI || cmp1_op == Op_SubI)) {
1338     // Skip cases were inputs of add/sub are not integers or of bottom type
1339     const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int();
1340     const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int();
1341     if ((r0 != NULL) && (r0 != TypeInt::INT) &&
1342         (r1 != NULL) && (r1 != TypeInt::INT) &&
1343         (cmp2_type != TypeInt::INT)) {
1344       // Compute exact (long) type range of add/sub result
1345       jlong lo_long = r0->_lo;
1346       jlong hi_long = r0->_hi;
1347       if (cmp1_op == Op_AddI) {
1348         lo_long += r1->_lo;
1349         hi_long += r1->_hi;
1350       } else {
1351         lo_long -= r1->_hi;
1352         hi_long -= r1->_lo;
1353       }
1354       // Check for over-/underflow by casting to integer
1355       int lo_int = (int)lo_long;
1356       int hi_int = (int)hi_long;
1357       bool underflow = lo_long != (jlong)lo_int;
1358       bool overflow  = hi_long != (jlong)hi_int;
1359       if ((underflow != overflow) && (hi_int < lo_int)) {
1360         // Overflow on one boundary, compute resulting type ranges:
1361         // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT]
1362         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
1363         const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w);
1364         const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w);
1365         // Compare second input of cmp to both type ranges
1366         const Type* sub_tr1 = cmp->sub(tr1, cmp2_type);
1367         const Type* sub_tr2 = cmp->sub(tr2, cmp2_type);
1368         if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) {
1369           // The result of the add/sub will never equal cmp2. Replace BoolNode
1370           // by false (0) if it tests for equality and by true (1) otherwise.
1371           return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1);
1372         }
1373       }
1374     }
1375   }
1376   return NULL;
1377 }
1378 
1379 static bool is_counted_loop_cmp(Node *cmp) {
1380   Node *n = cmp->in(1)->in(1);
1381   return n != NULL &&
1382          n->is_Phi() &&
1383          n->in(0) != NULL &&
1384          n->in(0)->is_CountedLoop() &&
1385          n->in(0)->as_CountedLoop()->phi() == n;
1386 }
1387 
1388 //------------------------------Ideal------------------------------------------
1389 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1390   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1391   // This moves the constant to the right.  Helps value-numbering.
1392   Node *cmp = in(1);
1393   if( !cmp->is_Sub() ) return NULL;
1394   int cop = cmp->Opcode();
1395   if( cop == Op_FastLock || cop == Op_FastUnlock) return NULL;
1396   Node *cmp1 = cmp->in(1);
1397   Node *cmp2 = cmp->in(2);
1398   if( !cmp1 ) return NULL;
1399 
1400   if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) {
1401     return NULL;
1402   }
1403 
1404   // Constant on left?
1405   Node *con = cmp1;
1406   uint op2 = cmp2->Opcode();
1407   // Move constants to the right of compare's to canonicalize.
1408   // Do not muck with Opaque1 nodes, as this indicates a loop
1409   // guard that cannot change shape.
1410   if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 &&
1411       // Because of NaN's, CmpD and CmpF are not commutative
1412       cop != Op_CmpD && cop != Op_CmpF &&
1413       // Protect against swapping inputs to a compare when it is used by a
1414       // counted loop exit, which requires maintaining the loop-limit as in(2)
1415       !is_counted_loop_exit_test() ) {
1416     // Ok, commute the constant to the right of the cmp node.
1417     // Clone the Node, getting a new Node of the same class
1418     cmp = cmp->clone();
1419     // Swap inputs to the clone
1420     cmp->swap_edges(1, 2);
1421     cmp = phase->transform( cmp );
1422     return new BoolNode( cmp, _test.commute() );
1423   }
1424 
1425   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1426   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1427   // test instead.
1428   int cmp1_op = cmp1->Opcode();
1429   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1430   if (cmp2_type == NULL)  return NULL;
1431   Node* j_xor = cmp1;
1432   if( cmp2_type == TypeInt::ZERO &&
1433       cmp1_op == Op_XorI &&
1434       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1435       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1436       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1437       (_test._test == BoolTest::eq ||
1438        _test._test == BoolTest::ne) ) {
1439     Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2));
1440     return new BoolNode( ncmp, _test.negate() );
1441   }
1442 
1443   // Change ((x & m) u<= m) or ((m & x) u<= m) to always true
1444   // Same with ((x & m) u< m+1) and ((m & x) u< m+1)
1445   if (cop == Op_CmpU &&
1446       cmp1_op == Op_AndI) {
1447     Node* bound = NULL;
1448     if (_test._test == BoolTest::le) {
1449       bound = cmp2;
1450     } else if (_test._test == BoolTest::lt &&
1451                cmp2->Opcode() == Op_AddI &&
1452                cmp2->in(2)->find_int_con(0) == 1) {
1453       bound = cmp2->in(1);
1454     }
1455     if (cmp1->in(2) == bound || cmp1->in(1) == bound) {
1456       return ConINode::make(1);
1457     }
1458   }
1459 
1460   // Change ((x & (m - 1)) u< m) into (m > 0)
1461   // This is the off-by-one variant of the above
1462   if (cop == Op_CmpU &&
1463       _test._test == BoolTest::lt &&
1464       cmp1_op == Op_AndI) {
1465     Node* l = cmp1->in(1);
1466     Node* r = cmp1->in(2);
1467     for (int repeat = 0; repeat < 2; repeat++) {
1468       bool match = r->Opcode() == Op_AddI && r->in(2)->find_int_con(0) == -1 &&
1469                    r->in(1) == cmp2;
1470       if (match) {
1471         // arraylength known to be non-negative, so a (arraylength != 0) is sufficient,
1472         // but to be compatible with the array range check pattern, use (arraylength u> 0)
1473         Node* ncmp = cmp2->Opcode() == Op_LoadRange
1474                      ? phase->transform(new CmpUNode(cmp2, phase->intcon(0)))
1475                      : phase->transform(new CmpINode(cmp2, phase->intcon(0)));
1476         return new BoolNode(ncmp, BoolTest::gt);
1477       } else {
1478         // commute and try again
1479         l = cmp1->in(2);
1480         r = cmp1->in(1);
1481       }
1482     }
1483   }
1484 
1485   // Change x u< 1 or x u<= 0 to x == 0
1486   if (cop == Op_CmpU &&
1487       cmp1_op != Op_LoadRange &&
1488       ((_test._test == BoolTest::lt &&
1489         cmp2->find_int_con(-1) == 1) ||
1490        (_test._test == BoolTest::le &&
1491         cmp2->find_int_con(-1) == 0))) {
1492     Node* ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1493     return new BoolNode(ncmp, BoolTest::eq);
1494   }
1495 
1496   // Change (arraylength <= 0) or (arraylength == 0)
1497   //   into (arraylength u<= 0)
1498   // Also change (arraylength != 0) into (arraylength u> 0)
1499   // The latter version matches the code pattern generated for
1500   // array range checks, which will more likely be optimized later.
1501   if (cop == Op_CmpI &&
1502       cmp1_op == Op_LoadRange &&
1503       cmp2->find_int_con(-1) == 0) {
1504     if (_test._test == BoolTest::le || _test._test == BoolTest::eq) {
1505       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1506       return new BoolNode(ncmp, BoolTest::le);
1507     } else if (_test._test == BoolTest::ne) {
1508       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1509       return new BoolNode(ncmp, BoolTest::gt);
1510     }
1511   }
1512 
1513   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1514   // This is a standard idiom for branching on a boolean value.
1515   Node *c2b = cmp1;
1516   if( cmp2_type == TypeInt::ZERO &&
1517       cmp1_op == Op_Conv2B &&
1518       (_test._test == BoolTest::eq ||
1519        _test._test == BoolTest::ne) ) {
1520     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1521        ? (Node*)new CmpINode(c2b->in(1),cmp2)
1522        : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1523     );
1524     return new BoolNode( ncmp, _test._test );
1525   }
1526 
1527   // Comparing a SubI against a zero is equal to comparing the SubI
1528   // arguments directly.  This only works for eq and ne comparisons
1529   // due to possible integer overflow.
1530   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1531         (cop == Op_CmpI) &&
1532         (cmp1_op == Op_SubI) &&
1533         ( cmp2_type == TypeInt::ZERO ) ) {
1534     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2)));
1535     return new BoolNode( ncmp, _test._test );
1536   }
1537 
1538   // Same as above but with and AddI of a constant
1539   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1540       cop == Op_CmpI &&
1541       cmp1_op == Op_AddI &&
1542       cmp1->in(2) != NULL &&
1543       phase->type(cmp1->in(2))->isa_int() &&
1544       phase->type(cmp1->in(2))->is_int()->is_con() &&
1545       cmp2_type == TypeInt::ZERO &&
1546       !is_counted_loop_cmp(cmp) // modifying the exit test of a counted loop messes the counted loop shape
1547       ) {
1548     const TypeInt* cmp1_in2 = phase->type(cmp1->in(2))->is_int();
1549     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),phase->intcon(-cmp1_in2->_hi)));
1550     return new BoolNode( ncmp, _test._test );
1551   }
1552 
1553   // Change "bool eq/ne (cmp (phi (X -X) 0))" into "bool eq/ne (cmp X 0)"
1554   // since zero check of conditional negation of an integer is equal to
1555   // zero check of the integer directly.
1556   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1557       (cop == Op_CmpI) &&
1558       (cmp2_type == TypeInt::ZERO) &&
1559       (cmp1_op == Op_Phi)) {
1560     // There should be a diamond phi with true path at index 1 or 2
1561     PhiNode *phi = cmp1->as_Phi();
1562     int idx_true = phi->is_diamond_phi();
1563     if (idx_true != 0) {
1564       // True input is in(idx_true) while false input is in(3 - idx_true)
1565       Node *tin = phi->in(idx_true);
1566       Node *fin = phi->in(3 - idx_true);
1567       if ((tin->Opcode() == Op_SubI) &&
1568           (phase->type(tin->in(1)) == TypeInt::ZERO) &&
1569           (tin->in(2) == fin)) {
1570         // Found conditional negation at true path, create a new CmpINode without that
1571         Node *ncmp = phase->transform(new CmpINode(fin, cmp2));
1572         return new BoolNode(ncmp, _test._test);
1573       }
1574       if ((fin->Opcode() == Op_SubI) &&
1575           (phase->type(fin->in(1)) == TypeInt::ZERO) &&
1576           (fin->in(2) == tin)) {
1577         // Found conditional negation at false path, create a new CmpINode without that
1578         Node *ncmp = phase->transform(new CmpINode(tin, cmp2));
1579         return new BoolNode(ncmp, _test._test);
1580       }
1581     }
1582   }
1583 
1584   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1585   // most general case because negating 0x80000000 does nothing.  Needed for
1586   // the CmpF3/SubI/CmpI idiom.
1587   if( cop == Op_CmpI &&
1588       cmp1_op == Op_SubI &&
1589       cmp2_type == TypeInt::ZERO &&
1590       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1591       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1592     Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2));
1593     return new BoolNode( ncmp, _test.commute() );
1594   }
1595 
1596   // Try to optimize signed integer comparison
1597   return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type);
1598 
1599   //  The transformation below is not valid for either signed or unsigned
1600   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1601   //  This transformation can be resurrected when we are able to
1602   //  make inferences about the range of values being subtracted from
1603   //  (or added to) relative to the wraparound point.
1604   //
1605   //    // Remove +/-1's if possible.
1606   //    // "X <= Y-1" becomes "X <  Y"
1607   //    // "X+1 <= Y" becomes "X <  Y"
1608   //    // "X <  Y+1" becomes "X <= Y"
1609   //    // "X-1 <  Y" becomes "X <= Y"
1610   //    // Do not this to compares off of the counted-loop-end.  These guys are
1611   //    // checking the trip counter and they want to use the post-incremented
1612   //    // counter.  If they use the PRE-incremented counter, then the counter has
1613   //    // to be incremented in a private block on a loop backedge.
1614   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1615   //      return NULL;
1616   //  #ifndef PRODUCT
1617   //    // Do not do this in a wash GVN pass during verification.
1618   //    // Gets triggered by too many simple optimizations to be bothered with
1619   //    // re-trying it again and again.
1620   //    if( !phase->allow_progress() ) return NULL;
1621   //  #endif
1622   //    // Not valid for unsigned compare because of corner cases in involving zero.
1623   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1624   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1625   //    // "0 <=u Y" is always true).
1626   //    if( cmp->Opcode() == Op_CmpU ) return NULL;
1627   //    int cmp2_op = cmp2->Opcode();
1628   //    if( _test._test == BoolTest::le ) {
1629   //      if( cmp1_op == Op_AddI &&
1630   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1631   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1632   //      else if( cmp2_op == Op_AddI &&
1633   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1634   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1635   //    } else if( _test._test == BoolTest::lt ) {
1636   //      if( cmp1_op == Op_AddI &&
1637   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1638   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1639   //      else if( cmp2_op == Op_AddI &&
1640   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1641   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1642   //    }
1643 }
1644 
1645 //------------------------------Value------------------------------------------
1646 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
1647 // based on local information.   If the input is constant, do it.
1648 const Type* BoolNode::Value(PhaseGVN* phase) const {
1649   return _test.cc2logical( phase->type( in(1) ) );
1650 }
1651 
1652 #ifndef PRODUCT
1653 //------------------------------dump_spec--------------------------------------
1654 // Dump special per-node info
1655 void BoolNode::dump_spec(outputStream *st) const {
1656   st->print("[");
1657   _test.dump_on(st);
1658   st->print("]");
1659 }
1660 
1661 //-------------------------------related---------------------------------------
1662 // A BoolNode's related nodes are all of its data inputs, and all of its
1663 // outputs until control nodes are hit, which are included. In compact
1664 // representation, inputs till level 3 and immediate outputs are included.
1665 void BoolNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
1666   if (compact) {
1667     this->collect_nodes(in_rel, 3, false, true);
1668     this->collect_nodes(out_rel, -1, false, false);
1669   } else {
1670     this->collect_nodes_in_all_data(in_rel, false);
1671     this->collect_nodes_out_all_ctrl_boundary(out_rel);
1672   }
1673 }
1674 #endif
1675 
1676 //----------------------is_counted_loop_exit_test------------------------------
1677 // Returns true if node is used by a counted loop node.
1678 bool BoolNode::is_counted_loop_exit_test() {
1679   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
1680     Node* use = fast_out(i);
1681     if (use->is_CountedLoopEnd()) {
1682       return true;
1683     }
1684   }
1685   return false;
1686 }
1687 
1688 //=============================================================================
1689 //------------------------------Value------------------------------------------
1690 // Compute sqrt
1691 const Type* SqrtDNode::Value(PhaseGVN* phase) const {
1692   const Type *t1 = phase->type( in(1) );
1693   if( t1 == Type::TOP ) return Type::TOP;
1694   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1695   double d = t1->getd();
1696   if( d < 0.0 ) return Type::DOUBLE;
1697   return TypeD::make( sqrt( d ) );
1698 }
1699 
1700 const Type* SqrtFNode::Value(PhaseGVN* phase) const {
1701   const Type *t1 = phase->type( in(1) );
1702   if( t1 == Type::TOP ) return Type::TOP;
1703   if( t1->base() != Type::FloatCon ) return Type::FLOAT;
1704   float f = t1->getf();
1705   if( f < 0.0f ) return Type::FLOAT;
1706   return TypeF::make( (float)sqrt( (double)f ) );
1707 }