1 /*
   2  * Copyright (c) 1997, 2017, 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 "memory/allocation.inline.hpp"
  28 #include "opto/addnode.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/cfgnode.hpp"
  31 #include "opto/loopnode.hpp"
  32 #include "opto/matcher.hpp"
  33 #include "opto/movenode.hpp"
  34 #include "opto/mulnode.hpp"
  35 #include "opto/opcodes.hpp"
  36 #include "opto/phaseX.hpp"
  37 #include "opto/subnode.hpp"
  38 #include "runtime/sharedRuntime.hpp"
  39 
  40 // Portions of code courtesy of Clifford Click
  41 
  42 // Optimization - Graph Style
  43 
  44 #include "math.h"
  45 
  46 //=============================================================================
  47 //------------------------------Identity---------------------------------------
  48 // If right input is a constant 0, return the left input.
  49 Node* SubNode::Identity(PhaseGVN* phase) {
  50   assert(in(1) != this, "Must already have called Value");
  51   assert(in(2) != this, "Must already have called Value");
  52 
  53   // Remove double negation
  54   const Type *zero = add_id();
  55   if( phase->type( in(1) )->higher_equal( zero ) &&
  56       in(2)->Opcode() == Opcode() &&
  57       phase->type( in(2)->in(1) )->higher_equal( zero ) ) {
  58     return in(2)->in(2);
  59   }
  60 
  61   // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y
  62   if( in(1)->Opcode() == Op_AddI ) {
  63     if( phase->eqv(in(1)->in(2),in(2)) )
  64       return in(1)->in(1);
  65     if (phase->eqv(in(1)->in(1),in(2)))
  66       return in(1)->in(2);
  67 
  68     // Also catch: "(X + Opaque2(Y)) - Y".  In this case, 'Y' is a loop-varying
  69     // trip counter and X is likely to be loop-invariant (that's how O2 Nodes
  70     // are originally used, although the optimizer sometimes jiggers things).
  71     // This folding through an O2 removes a loop-exit use of a loop-varying
  72     // value and generally lowers register pressure in and around the loop.
  73     if( in(1)->in(2)->Opcode() == Op_Opaque2 &&
  74         phase->eqv(in(1)->in(2)->in(1),in(2)) )
  75       return in(1)->in(1);
  76   }
  77 
  78   return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this;
  79 }
  80 
  81 //------------------------------Value------------------------------------------
  82 // A subtract node differences it's two inputs.
  83 const Type* SubNode::Value_common(PhaseTransform *phase) const {
  84   const Node* in1 = in(1);
  85   const Node* in2 = in(2);
  86   // Either input is TOP ==> the result is TOP
  87   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  88   if( t1 == Type::TOP ) return Type::TOP;
  89   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  90   if( t2 == Type::TOP ) return Type::TOP;
  91 
  92   // Not correct for SubFnode and AddFNode (must check for infinity)
  93   // Equal?  Subtract is zero
  94   if (in1->eqv_uncast(in2))  return add_id();
  95 
  96   // Either input is BOTTOM ==> the result is the local BOTTOM
  97   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
  98     return bottom_type();
  99 
 100   return NULL;
 101 }
 102 
 103 const Type* SubNode::Value(PhaseGVN* phase) const {
 104   const Type* t = Value_common(phase);
 105   if (t != NULL) {
 106     return t;
 107   }
 108   const Type* t1 = phase->type(in(1));
 109   const Type* t2 = phase->type(in(2));
 110   return sub(t1,t2);            // Local flavor of type subtraction
 111 
 112 }
 113 
 114 //=============================================================================
 115 
 116 //------------------------------Helper function--------------------------------
 117 static bool ok_to_convert(Node* inc, Node* iv) {
 118     // Do not collapse (x+c0)-y if "+" is a loop increment, because the
 119     // "-" is loop invariant and collapsing extends the live-range of "x"
 120     // to overlap with the "+", forcing another register to be used in
 121     // the loop.
 122     // This test will be clearer with '&&' (apply DeMorgan's rule)
 123     // but I like the early cutouts that happen here.
 124     const PhiNode *phi;
 125     if( ( !inc->in(1)->is_Phi() ||
 126           !(phi=inc->in(1)->as_Phi()) ||
 127           phi->is_copy() ||
 128           !phi->region()->is_CountedLoop() ||
 129           inc != phi->region()->as_CountedLoop()->incr() )
 130        &&
 131         // Do not collapse (x+c0)-iv if "iv" is a loop induction variable,
 132         // because "x" maybe invariant.
 133         ( !iv->is_loop_iv() )
 134       ) {
 135       return true;
 136     } else {
 137       return false;
 138     }
 139 }
 140 //------------------------------Ideal------------------------------------------
 141 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
 142   Node *in1 = in(1);
 143   Node *in2 = in(2);
 144   uint op1 = in1->Opcode();
 145   uint op2 = in2->Opcode();
 146 
 147 #ifdef ASSERT
 148   // Check for dead loop
 149   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 150       ( ( op1 == Op_AddI || op1 == Op_SubI ) &&
 151         ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 152           phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1 ) ) ) )
 153     assert(false, "dead loop in SubINode::Ideal");
 154 #endif
 155 
 156   const Type *t2 = phase->type( in2 );
 157   if( t2 == Type::TOP ) return NULL;
 158   // Convert "x-c0" into "x+ -c0".
 159   if( t2->base() == Type::Int ){        // Might be bottom or top...
 160     const TypeInt *i = t2->is_int();
 161     if( i->is_con() )
 162       return new AddINode(in1, phase->intcon(-i->get_con()));
 163   }
 164 
 165   // Convert "(x+c0) - y" into (x-y) + c0"
 166   // Do not collapse (x+c0)-y if "+" is a loop increment or
 167   // if "y" is a loop induction variable.
 168   if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
 169     const Type *tadd = phase->type( in1->in(2) );
 170     if( tadd->singleton() && tadd != Type::TOP ) {
 171       Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 ));
 172       return new AddINode( sub2, in1->in(2) );
 173     }
 174   }
 175 
 176 
 177   // Convert "x - (y+c0)" into "(x-y) - c0"
 178   // Need the same check as in above optimization but reversed.
 179   if (op2 == Op_AddI && ok_to_convert(in2, in1)) {
 180     Node* in21 = in2->in(1);
 181     Node* in22 = in2->in(2);
 182     const TypeInt* tcon = phase->type(in22)->isa_int();
 183     if (tcon != NULL && tcon->is_con()) {
 184       Node* sub2 = phase->transform( new SubINode(in1, in21) );
 185       Node* neg_c0 = phase->intcon(- tcon->get_con());
 186       return new AddINode(sub2, neg_c0);
 187     }
 188   }
 189 
 190   const Type *t1 = phase->type( in1 );
 191   if( t1 == Type::TOP ) return NULL;
 192 
 193 #ifdef ASSERT
 194   // Check for dead loop
 195   if( ( op2 == Op_AddI || op2 == Op_SubI ) &&
 196       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 197         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 198     assert(false, "dead loop in SubINode::Ideal");
 199 #endif
 200 
 201   // Convert "x - (x+y)" into "-y"
 202   if( op2 == Op_AddI &&
 203       phase->eqv( in1, in2->in(1) ) )
 204     return new SubINode( phase->intcon(0),in2->in(2));
 205   // Convert "(x-y) - x" into "-y"
 206   if( op1 == Op_SubI &&
 207       phase->eqv( in1->in(1), in2 ) )
 208     return new SubINode( phase->intcon(0),in1->in(2));
 209   // Convert "x - (y+x)" into "-y"
 210   if( op2 == Op_AddI &&
 211       phase->eqv( in1, in2->in(2) ) )
 212     return new SubINode( phase->intcon(0),in2->in(1));
 213 
 214   // Convert "0 - (x-y)" into "y-x"
 215   if( t1 == TypeInt::ZERO && op2 == Op_SubI )
 216     return new SubINode( in2->in(2), in2->in(1) );
 217 
 218   // Convert "0 - (x+con)" into "-con-x"
 219   jint con;
 220   if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
 221       (con = in2->in(2)->find_int_con(0)) != 0 )
 222     return new SubINode( phase->intcon(-con), in2->in(1) );
 223 
 224   // Convert "(X+A) - (X+B)" into "A - B"
 225   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
 226     return new SubINode( in1->in(2), in2->in(2) );
 227 
 228   // Convert "(A+X) - (B+X)" into "A - B"
 229   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
 230     return new SubINode( in1->in(1), in2->in(1) );
 231 
 232   // Convert "(A+X) - (X+B)" into "A - B"
 233   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
 234     return new SubINode( in1->in(1), in2->in(2) );
 235 
 236   // Convert "(X+A) - (B+X)" into "A - B"
 237   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
 238     return new SubINode( in1->in(2), in2->in(1) );
 239 
 240   // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
 241   // nicer to optimize than subtract.
 242   if( op2 == Op_SubI && in2->outcnt() == 1) {
 243     Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) );
 244     return new SubINode( add1, in2->in(1) );
 245   }
 246 
 247   return NULL;
 248 }
 249 
 250 //------------------------------sub--------------------------------------------
 251 // A subtract node differences it's two inputs.
 252 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
 253   const TypeInt *r0 = t1->is_int(); // Handy access
 254   const TypeInt *r1 = t2->is_int();
 255   int32_t lo = java_subtract(r0->_lo, r1->_hi);
 256   int32_t hi = java_subtract(r0->_hi, r1->_lo);
 257 
 258   // We next check for 32-bit overflow.
 259   // If that happens, we just assume all integers are possible.
 260   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 261        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 262       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 263        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 264     return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 265   else                          // Overflow; assume all integers
 266     return TypeInt::INT;
 267 }
 268 
 269 //=============================================================================
 270 //------------------------------Ideal------------------------------------------
 271 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 272   Node *in1 = in(1);
 273   Node *in2 = in(2);
 274   uint op1 = in1->Opcode();
 275   uint op2 = in2->Opcode();
 276 
 277 #ifdef ASSERT
 278   // Check for dead loop
 279   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 280       ( ( op1 == Op_AddL || op1 == Op_SubL ) &&
 281         ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 282           phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1  ) ) ) )
 283     assert(false, "dead loop in SubLNode::Ideal");
 284 #endif
 285 
 286   if( phase->type( in2 ) == Type::TOP ) return NULL;
 287   const TypeLong *i = phase->type( in2 )->isa_long();
 288   // Convert "x-c0" into "x+ -c0".
 289   if( i &&                      // Might be bottom or top...
 290       i->is_con() )
 291     return new AddLNode(in1, phase->longcon(-i->get_con()));
 292 
 293   // Convert "(x+c0) - y" into (x-y) + c0"
 294   // Do not collapse (x+c0)-y if "+" is a loop increment or
 295   // if "y" is a loop induction variable.
 296   if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
 297     Node *in11 = in1->in(1);
 298     const Type *tadd = phase->type( in1->in(2) );
 299     if( tadd->singleton() && tadd != Type::TOP ) {
 300       Node *sub2 = phase->transform( new SubLNode( in11, in2 ));
 301       return new AddLNode( sub2, in1->in(2) );
 302     }
 303   }
 304 
 305   // Convert "x - (y+c0)" into "(x-y) - c0"
 306   // Need the same check as in above optimization but reversed.
 307   if (op2 == Op_AddL && ok_to_convert(in2, in1)) {
 308     Node* in21 = in2->in(1);
 309     Node* in22 = in2->in(2);
 310     const TypeLong* tcon = phase->type(in22)->isa_long();
 311     if (tcon != NULL && tcon->is_con()) {
 312       Node* sub2 = phase->transform( new SubLNode(in1, in21) );
 313       Node* neg_c0 = phase->longcon(- tcon->get_con());
 314       return new AddLNode(sub2, neg_c0);
 315     }
 316   }
 317 
 318   const Type *t1 = phase->type( in1 );
 319   if( t1 == Type::TOP ) return NULL;
 320 
 321 #ifdef ASSERT
 322   // Check for dead loop
 323   if( ( op2 == Op_AddL || op2 == Op_SubL ) &&
 324       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 325         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 326     assert(false, "dead loop in SubLNode::Ideal");
 327 #endif
 328 
 329   // Convert "x - (x+y)" into "-y"
 330   if( op2 == Op_AddL &&
 331       phase->eqv( in1, in2->in(1) ) )
 332     return new SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2));
 333   // Convert "x - (y+x)" into "-y"
 334   if( op2 == Op_AddL &&
 335       phase->eqv( in1, in2->in(2) ) )
 336     return new SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1));
 337 
 338   // Convert "0 - (x-y)" into "y-x"
 339   if( phase->type( in1 ) == TypeLong::ZERO && op2 == Op_SubL )
 340     return new SubLNode( in2->in(2), in2->in(1) );
 341 
 342   // Convert "(X+A) - (X+B)" into "A - B"
 343   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
 344     return new SubLNode( in1->in(2), in2->in(2) );
 345 
 346   // Convert "(A+X) - (B+X)" into "A - B"
 347   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
 348     return new SubLNode( in1->in(1), in2->in(1) );
 349 
 350   // Convert "A-(B-C)" into (A+C)-B"
 351   if( op2 == Op_SubL && in2->outcnt() == 1) {
 352     Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) );
 353     return new SubLNode( add1, in2->in(1) );
 354   }
 355 
 356   return NULL;
 357 }
 358 
 359 //------------------------------sub--------------------------------------------
 360 // A subtract node differences it's two inputs.
 361 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
 362   const TypeLong *r0 = t1->is_long(); // Handy access
 363   const TypeLong *r1 = t2->is_long();
 364   jlong lo = java_subtract(r0->_lo, r1->_hi);
 365   jlong hi = java_subtract(r0->_hi, r1->_lo);
 366 
 367   // We next check for 32-bit overflow.
 368   // If that happens, we just assume all integers are possible.
 369   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 370        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 371       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 372        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 373     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 374   else                          // Overflow; assume all integers
 375     return TypeLong::LONG;
 376 }
 377 
 378 //=============================================================================
 379 //------------------------------Value------------------------------------------
 380 // A subtract node differences its two inputs.
 381 const Type* SubFPNode::Value(PhaseGVN* phase) const {
 382   const Node* in1 = in(1);
 383   const Node* in2 = in(2);
 384   // Either input is TOP ==> the result is TOP
 385   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 386   if( t1 == Type::TOP ) return Type::TOP;
 387   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 388   if( t2 == Type::TOP ) return Type::TOP;
 389 
 390   // if both operands are infinity of same sign, the result is NaN; do
 391   // not replace with zero
 392   if( (t1->is_finite() && t2->is_finite()) ) {
 393     if( phase->eqv(in1, in2) ) return add_id();
 394   }
 395 
 396   // Either input is BOTTOM ==> the result is the local BOTTOM
 397   const Type *bot = bottom_type();
 398   if( (t1 == bot) || (t2 == bot) ||
 399       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 400     return bot;
 401 
 402   return sub(t1,t2);            // Local flavor of type subtraction
 403 }
 404 
 405 
 406 //=============================================================================
 407 //------------------------------Ideal------------------------------------------
 408 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 409   const Type *t2 = phase->type( in(2) );
 410   // Convert "x-c0" into "x+ -c0".
 411   if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
 412     // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
 413   }
 414 
 415   // Not associative because of boundary conditions (infinity)
 416   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 417     // Convert "x - (x+y)" into "-y"
 418     if( in(2)->is_Add() &&
 419         phase->eqv(in(1),in(2)->in(1) ) )
 420       return new SubFNode( phase->makecon(TypeF::ZERO),in(2)->in(2));
 421   }
 422 
 423   // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
 424   // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
 425   //if( phase->type(in(1)) == TypeF::ZERO )
 426   //return new (phase->C, 2) NegFNode(in(2));
 427 
 428   return NULL;
 429 }
 430 
 431 //------------------------------sub--------------------------------------------
 432 // A subtract node differences its two inputs.
 433 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
 434   // no folding if one of operands is infinity or NaN, do not do constant folding
 435   if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
 436     return TypeF::make( t1->getf() - t2->getf() );
 437   }
 438   else if( g_isnan(t1->getf()) ) {
 439     return t1;
 440   }
 441   else if( g_isnan(t2->getf()) ) {
 442     return t2;
 443   }
 444   else {
 445     return Type::FLOAT;
 446   }
 447 }
 448 
 449 //=============================================================================
 450 //------------------------------Ideal------------------------------------------
 451 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 452   const Type *t2 = phase->type( in(2) );
 453   // Convert "x-c0" into "x+ -c0".
 454   if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
 455     // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
 456   }
 457 
 458   // Not associative because of boundary conditions (infinity)
 459   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 460     // Convert "x - (x+y)" into "-y"
 461     if( in(2)->is_Add() &&
 462         phase->eqv(in(1),in(2)->in(1) ) )
 463       return new SubDNode( phase->makecon(TypeD::ZERO),in(2)->in(2));
 464   }
 465 
 466   // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
 467   // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
 468   //if( phase->type(in(1)) == TypeD::ZERO )
 469   //return new (phase->C, 2) NegDNode(in(2));
 470 
 471   return NULL;
 472 }
 473 
 474 //------------------------------sub--------------------------------------------
 475 // A subtract node differences its two inputs.
 476 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
 477   // no folding if one of operands is infinity or NaN, do not do constant folding
 478   if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
 479     return TypeD::make( t1->getd() - t2->getd() );
 480   }
 481   else if( g_isnan(t1->getd()) ) {
 482     return t1;
 483   }
 484   else if( g_isnan(t2->getd()) ) {
 485     return t2;
 486   }
 487   else {
 488     return Type::DOUBLE;
 489   }
 490 }
 491 
 492 //=============================================================================
 493 //------------------------------Idealize---------------------------------------
 494 // Unlike SubNodes, compare must still flatten return value to the
 495 // range -1, 0, 1.
 496 // And optimizations like those for (X + Y) - X fail if overflow happens.
 497 Node* CmpNode::Identity(PhaseGVN* phase) {
 498   return this;
 499 }
 500 
 501 #ifndef PRODUCT
 502 //----------------------------related------------------------------------------
 503 // Related nodes of comparison nodes include all data inputs (until hitting a
 504 // control boundary) as well as all outputs until and including control nodes
 505 // as well as their projections. In compact mode, data inputs till depth 1 and
 506 // all outputs till depth 1 are considered.
 507 void CmpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
 508   if (compact) {
 509     this->collect_nodes(in_rel, 1, false, true);
 510     this->collect_nodes(out_rel, -1, false, false);
 511   } else {
 512     this->collect_nodes_in_all_data(in_rel, false);
 513     this->collect_nodes_out_all_ctrl_boundary(out_rel);
 514     // Now, find all control nodes in out_rel, and include their projections
 515     // and projection targets (if any) in the result.
 516     GrowableArray<Node*> proj(Compile::current()->unique());
 517     for (GrowableArrayIterator<Node*> it = out_rel->begin(); it != out_rel->end(); ++it) {
 518       Node* n = *it;
 519       if (n->is_CFG() && !n->is_Proj()) {
 520         // Assume projections and projection targets are found at levels 1 and 2.
 521         n->collect_nodes(&proj, -2, false, false);
 522         for (GrowableArrayIterator<Node*> p = proj.begin(); p != proj.end(); ++p) {
 523           out_rel->append_if_missing(*p);
 524         }
 525         proj.clear();
 526       }
 527     }
 528   }
 529 }
 530 #endif
 531 
 532 //=============================================================================
 533 //------------------------------cmp--------------------------------------------
 534 // Simplify a CmpI (compare 2 integers) node, based on local information.
 535 // If both inputs are constants, compare them.
 536 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 537   const TypeInt *r0 = t1->is_int(); // Handy access
 538   const TypeInt *r1 = t2->is_int();
 539 
 540   if( r0->_hi < r1->_lo )       // Range is always low?
 541     return TypeInt::CC_LT;
 542   else if( r0->_lo > r1->_hi )  // Range is always high?
 543     return TypeInt::CC_GT;
 544 
 545   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 546     assert(r0->get_con() == r1->get_con(), "must be equal");
 547     return TypeInt::CC_EQ;      // Equal results.
 548   } else if( r0->_hi == r1->_lo ) // Range is never high?
 549     return TypeInt::CC_LE;
 550   else if( r0->_lo == r1->_hi ) // Range is never low?
 551     return TypeInt::CC_GE;
 552   return TypeInt::CC;           // else use worst case results
 553 }
 554 
 555 // Simplify a CmpU (compare 2 integers) node, based on local information.
 556 // If both inputs are constants, compare them.
 557 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 558   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 559 
 560   // comparing two unsigned ints
 561   const TypeInt *r0 = t1->is_int();   // Handy access
 562   const TypeInt *r1 = t2->is_int();
 563 
 564   // Current installed version
 565   // Compare ranges for non-overlap
 566   juint lo0 = r0->_lo;
 567   juint hi0 = r0->_hi;
 568   juint lo1 = r1->_lo;
 569   juint hi1 = r1->_hi;
 570 
 571   // If either one has both negative and positive values,
 572   // it therefore contains both 0 and -1, and since [0..-1] is the
 573   // full unsigned range, the type must act as an unsigned bottom.
 574   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 575   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 576 
 577   if (bot0 || bot1) {
 578     // All unsigned values are LE -1 and GE 0.
 579     if (lo0 == 0 && hi0 == 0) {
 580       return TypeInt::CC_LE;            //   0 <= bot
 581     } else if ((jint)lo0 == -1 && (jint)hi0 == -1) {
 582       return TypeInt::CC_GE;            // -1 >= bot
 583     } else if (lo1 == 0 && hi1 == 0) {
 584       return TypeInt::CC_GE;            // bot >= 0
 585     } else if ((jint)lo1 == -1 && (jint)hi1 == -1) {
 586       return TypeInt::CC_LE;            // bot <= -1
 587     }
 588   } else {
 589     // We can use ranges of the form [lo..hi] if signs are the same.
 590     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 591     // results are reversed, '-' > '+' for unsigned compare
 592     if (hi0 < lo1) {
 593       return TypeInt::CC_LT;            // smaller
 594     } else if (lo0 > hi1) {
 595       return TypeInt::CC_GT;            // greater
 596     } else if (hi0 == lo1 && lo0 == hi1) {
 597       return TypeInt::CC_EQ;            // Equal results
 598     } else if (lo0 >= hi1) {
 599       return TypeInt::CC_GE;
 600     } else if (hi0 <= lo1) {
 601       // Check for special case in Hashtable::get.  (See below.)
 602       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 603         return TypeInt::CC_LT;
 604       return TypeInt::CC_LE;
 605     }
 606   }
 607   // Check for special case in Hashtable::get - the hash index is
 608   // mod'ed to the table size so the following range check is useless.
 609   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 610   // to be positive.
 611   // (This is a gross hack, since the sub method never
 612   // looks at the structure of the node in any other case.)
 613   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 614     return TypeInt::CC_LT;
 615   return TypeInt::CC;                   // else use worst case results
 616 }
 617 
 618 const Type* CmpUNode::Value(PhaseGVN* phase) const {
 619   const Type* t = SubNode::Value_common(phase);
 620   if (t != NULL) {
 621     return t;
 622   }
 623   const Node* in1 = in(1);
 624   const Node* in2 = in(2);
 625   const Type* t1 = phase->type(in1);
 626   const Type* t2 = phase->type(in2);
 627   assert(t1->isa_int(), "CmpU has only Int type inputs");
 628   if (t2 == TypeInt::INT) { // Compare to bottom?
 629     return bottom_type();
 630   }
 631   uint in1_op = in1->Opcode();
 632   if (in1_op == Op_AddI || in1_op == Op_SubI) {
 633     // The problem rise when result of AddI(SubI) may overflow
 634     // signed integer value. Let say the input type is
 635     // [256, maxint] then +128 will create 2 ranges due to
 636     // overflow: [minint, minint+127] and [384, maxint].
 637     // But C2 type system keep only 1 type range and as result
 638     // it use general [minint, maxint] for this case which we
 639     // can't optimize.
 640     //
 641     // Make 2 separate type ranges based on types of AddI(SubI) inputs
 642     // and compare results of their compare. If results are the same
 643     // CmpU node can be optimized.
 644     const Node* in11 = in1->in(1);
 645     const Node* in12 = in1->in(2);
 646     const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11);
 647     const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12);
 648     // Skip cases when input types are top or bottom.
 649     if ((t11 != Type::TOP) && (t11 != TypeInt::INT) &&
 650         (t12 != Type::TOP) && (t12 != TypeInt::INT)) {
 651       const TypeInt *r0 = t11->is_int();
 652       const TypeInt *r1 = t12->is_int();
 653       jlong lo_r0 = r0->_lo;
 654       jlong hi_r0 = r0->_hi;
 655       jlong lo_r1 = r1->_lo;
 656       jlong hi_r1 = r1->_hi;
 657       if (in1_op == Op_SubI) {
 658         jlong tmp = hi_r1;
 659         hi_r1 = -lo_r1;
 660         lo_r1 = -tmp;
 661         // Note, for substructing [minint,x] type range
 662         // long arithmetic provides correct overflow answer.
 663         // The confusion come from the fact that in 32-bit
 664         // -minint == minint but in 64-bit -minint == maxint+1.
 665       }
 666       jlong lo_long = lo_r0 + lo_r1;
 667       jlong hi_long = hi_r0 + hi_r1;
 668       int lo_tr1 = min_jint;
 669       int hi_tr1 = (int)hi_long;
 670       int lo_tr2 = (int)lo_long;
 671       int hi_tr2 = max_jint;
 672       bool underflow = lo_long != (jlong)lo_tr2;
 673       bool overflow  = hi_long != (jlong)hi_tr1;
 674       // Use sub(t1, t2) when there is no overflow (one type range)
 675       // or when both overflow and underflow (too complex).
 676       if ((underflow != overflow) && (hi_tr1 < lo_tr2)) {
 677         // Overflow only on one boundary, compare 2 separate type ranges.
 678         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
 679         const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w);
 680         const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w);
 681         const Type* cmp1 = sub(tr1, t2);
 682         const Type* cmp2 = sub(tr2, t2);
 683         if (cmp1 == cmp2) {
 684           return cmp1; // Hit!
 685         }
 686       }
 687     }
 688   }
 689 
 690   return sub(t1, t2);            // Local flavor of type subtraction
 691 }
 692 
 693 bool CmpUNode::is_index_range_check() const {
 694   // Check for the "(X ModI Y) CmpU Y" shape
 695   return (in(1)->Opcode() == Op_ModI &&
 696           in(1)->in(2)->eqv_uncast(in(2)));
 697 }
 698 
 699 //------------------------------Idealize---------------------------------------
 700 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 701   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 702     switch (in(1)->Opcode()) {
 703     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 704       return new CmpLNode(in(1)->in(1),in(1)->in(2));
 705     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 706       return new CmpFNode(in(1)->in(1),in(1)->in(2));
 707     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 708       return new CmpDNode(in(1)->in(1),in(1)->in(2));
 709     //case Op_SubI:
 710       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 711       // can be turned into (x <?> y).
 712       // This is handled (with more general cases) by Ideal_sub_algebra.
 713     }
 714   }
 715   return NULL;                  // No change
 716 }
 717 
 718 
 719 //=============================================================================
 720 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 721 // If both inputs are constants, compare them.
 722 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 723   const TypeLong *r0 = t1->is_long(); // Handy access
 724   const TypeLong *r1 = t2->is_long();
 725 
 726   if( r0->_hi < r1->_lo )       // Range is always low?
 727     return TypeInt::CC_LT;
 728   else if( r0->_lo > r1->_hi )  // Range is always high?
 729     return TypeInt::CC_GT;
 730 
 731   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 732     assert(r0->get_con() == r1->get_con(), "must be equal");
 733     return TypeInt::CC_EQ;      // Equal results.
 734   } else if( r0->_hi == r1->_lo ) // Range is never high?
 735     return TypeInt::CC_LE;
 736   else if( r0->_lo == r1->_hi ) // Range is never low?
 737     return TypeInt::CC_GE;
 738   return TypeInt::CC;           // else use worst case results
 739 }
 740 
 741 
 742 // Simplify a CmpUL (compare 2 unsigned longs) node, based on local information.
 743 // If both inputs are constants, compare them.
 744 const Type* CmpULNode::sub(const Type* t1, const Type* t2) const {
 745   assert(!t1->isa_ptr(), "obsolete usage of CmpUL");
 746 
 747   // comparing two unsigned longs
 748   const TypeLong* r0 = t1->is_long();   // Handy access
 749   const TypeLong* r1 = t2->is_long();
 750 
 751   // Current installed version
 752   // Compare ranges for non-overlap
 753   julong lo0 = r0->_lo;
 754   julong hi0 = r0->_hi;
 755   julong lo1 = r1->_lo;
 756   julong hi1 = r1->_hi;
 757 
 758   // If either one has both negative and positive values,
 759   // it therefore contains both 0 and -1, and since [0..-1] is the
 760   // full unsigned range, the type must act as an unsigned bottom.
 761   bool bot0 = ((jlong)(lo0 ^ hi0) < 0);
 762   bool bot1 = ((jlong)(lo1 ^ hi1) < 0);
 763 
 764   if (bot0 || bot1) {
 765     // All unsigned values are LE -1 and GE 0.
 766     if (lo0 == 0 && hi0 == 0) {
 767       return TypeInt::CC_LE;            //   0 <= bot
 768     } else if ((jlong)lo0 == -1 && (jlong)hi0 == -1) {
 769       return TypeInt::CC_GE;            // -1 >= bot
 770     } else if (lo1 == 0 && hi1 == 0) {
 771       return TypeInt::CC_GE;            // bot >= 0
 772     } else if ((jlong)lo1 == -1 && (jlong)hi1 == -1) {
 773       return TypeInt::CC_LE;            // bot <= -1
 774     }
 775   } else {
 776     // We can use ranges of the form [lo..hi] if signs are the same.
 777     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 778     // results are reversed, '-' > '+' for unsigned compare
 779     if (hi0 < lo1) {
 780       return TypeInt::CC_LT;            // smaller
 781     } else if (lo0 > hi1) {
 782       return TypeInt::CC_GT;            // greater
 783     } else if (hi0 == lo1 && lo0 == hi1) {
 784       return TypeInt::CC_EQ;            // Equal results
 785     } else if (lo0 >= hi1) {
 786       return TypeInt::CC_GE;
 787     } else if (hi0 <= lo1) {
 788       return TypeInt::CC_LE;
 789     }
 790   }
 791 
 792   return TypeInt::CC;                   // else use worst case results
 793 }
 794 
 795 //=============================================================================
 796 //------------------------------sub--------------------------------------------
 797 // Simplify an CmpP (compare 2 pointers) node, based on local information.
 798 // If both inputs are constants, compare them.
 799 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
 800   const TypePtr *r0 = t1->is_ptr(); // Handy access
 801   const TypePtr *r1 = t2->is_ptr();
 802 
 803   // Undefined inputs makes for an undefined result
 804   if( TypePtr::above_centerline(r0->_ptr) ||
 805       TypePtr::above_centerline(r1->_ptr) )
 806     return Type::TOP;
 807 
 808   if (r0 == r1 && r0->singleton()) {
 809     // Equal pointer constants (klasses, nulls, etc.)
 810     return TypeInt::CC_EQ;
 811   }
 812 
 813   // See if it is 2 unrelated classes.
 814   const TypeOopPtr* p0 = r0->isa_oopptr();
 815   const TypeOopPtr* p1 = r1->isa_oopptr();
 816   if (p0 && p1) {
 817     Node* in1 = in(1)->uncast();
 818     Node* in2 = in(2)->uncast();
 819     AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
 820     AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
 821     if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
 822       return TypeInt::CC_GT;  // different pointers
 823     }
 824     ciKlass* klass0 = p0->klass();
 825     bool    xklass0 = p0->klass_is_exact();
 826     ciKlass* klass1 = p1->klass();
 827     bool    xklass1 = p1->klass_is_exact();
 828     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 829     if (klass0 && klass1 &&
 830         kps != 1 &&             // both or neither are klass pointers
 831         klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
 832         klass1->is_loaded() && !klass1->is_interface() &&
 833         (!klass0->is_obj_array_klass() ||
 834          !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
 835         (!klass1->is_obj_array_klass() ||
 836          !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
 837       bool unrelated_classes = false;
 838       // See if neither subclasses the other, or if the class on top
 839       // is precise.  In either of these cases, the compare is known
 840       // to fail if at least one of the pointers is provably not null.
 841       if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
 842         // Do nothing; we know nothing for imprecise types
 843       } else if (klass0->is_subtype_of(klass1)) {
 844         // If klass1's type is PRECISE, then classes are unrelated.
 845         unrelated_classes = xklass1;
 846       } else if (klass1->is_subtype_of(klass0)) {
 847         // If klass0's type is PRECISE, then classes are unrelated.
 848         unrelated_classes = xklass0;
 849       } else {                  // Neither subtypes the other
 850         unrelated_classes = true;
 851       }
 852       if (unrelated_classes) {
 853         // The oops classes are known to be unrelated. If the joined PTRs of
 854         // two oops is not Null and not Bottom, then we are sure that one
 855         // of the two oops is non-null, and the comparison will always fail.
 856         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 857         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 858           return TypeInt::CC_GT;
 859         }
 860       }
 861     }
 862   }
 863 
 864   // Known constants can be compared exactly
 865   // Null can be distinguished from any NotNull pointers
 866   // Unknown inputs makes an unknown result
 867   if( r0->singleton() ) {
 868     intptr_t bits0 = r0->get_con();
 869     if( r1->singleton() )
 870       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 871     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 872   } else if( r1->singleton() ) {
 873     intptr_t bits1 = r1->get_con();
 874     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 875   } else
 876     return TypeInt::CC;
 877 }
 878 
 879 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
 880   // Return the klass node for
 881   //   LoadP(AddP(foo:Klass, #java_mirror))
 882   //   or NULL if not matching.
 883   if (n->Opcode() != Op_LoadP) return NULL;
 884 
 885   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 886   if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;
 887 
 888   Node* adr = n->in(MemNode::Address);




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