1 /*
   2  * Copyright (c) 1997, 2012, 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/connode.hpp"
  32 #include "opto/loopnode.hpp"
  33 #include "opto/matcher.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( PhaseTransform *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( 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 sub(t1,t2);            // Local flavor of type subtraction
 101 
 102 }
 103 
 104 //=============================================================================
 105 
 106 //------------------------------Helper function--------------------------------
 107 static bool ok_to_convert(Node* inc, Node* iv) {
 108     // Do not collapse (x+c0)-y if "+" is a loop increment, because the
 109     // "-" is loop invariant and collapsing extends the live-range of "x"
 110     // to overlap with the "+", forcing another register to be used in
 111     // the loop.
 112     // This test will be clearer with '&&' (apply DeMorgan's rule)
 113     // but I like the early cutouts that happen here.
 114     const PhiNode *phi;
 115     if( ( !inc->in(1)->is_Phi() ||
 116           !(phi=inc->in(1)->as_Phi()) ||
 117           phi->is_copy() ||
 118           !phi->region()->is_CountedLoop() ||
 119           inc != phi->region()->as_CountedLoop()->incr() )
 120        &&
 121         // Do not collapse (x+c0)-iv if "iv" is a loop induction variable,
 122         // because "x" maybe invariant.
 123         ( !iv->is_loop_iv() )
 124       ) {
 125       return true;
 126     } else {
 127       return false;
 128     }
 129 }
 130 //------------------------------Ideal------------------------------------------
 131 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
 132   Node *in1 = in(1);
 133   Node *in2 = in(2);
 134   uint op1 = in1->Opcode();
 135   uint op2 = in2->Opcode();
 136 
 137 #ifdef ASSERT
 138   // Check for dead loop
 139   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 140       ( op1 == Op_AddI || op1 == Op_SubI ) &&
 141       ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 142         phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1 ) ) )
 143     assert(false, "dead loop in SubINode::Ideal");
 144 #endif
 145 
 146   const Type *t2 = phase->type( in2 );
 147   if( t2 == Type::TOP ) return NULL;
 148   // Convert "x-c0" into "x+ -c0".
 149   if( t2->base() == Type::Int ){        // Might be bottom or top...
 150     const TypeInt *i = t2->is_int();
 151     if( i->is_con() )
 152       return new (phase->C) AddINode(in1, phase->intcon(-i->get_con()));
 153   }
 154 
 155   // Convert "(x+c0) - y" into (x-y) + c0"
 156   // Do not collapse (x+c0)-y if "+" is a loop increment or
 157   // if "y" is a loop induction variable.
 158   if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
 159     const Type *tadd = phase->type( in1->in(2) );
 160     if( tadd->singleton() && tadd != Type::TOP ) {
 161       Node *sub2 = phase->transform( new (phase->C) SubINode( in1->in(1), in2 ));
 162       return new (phase->C) AddINode( sub2, in1->in(2) );
 163     }
 164   }
 165 
 166 
 167   // Convert "x - (y+c0)" into "(x-y) - c0"
 168   // Need the same check as in above optimization but reversed.
 169   if (op2 == Op_AddI && ok_to_convert(in2, in1)) {
 170     Node* in21 = in2->in(1);
 171     Node* in22 = in2->in(2);
 172     const TypeInt* tcon = phase->type(in22)->isa_int();
 173     if (tcon != NULL && tcon->is_con()) {
 174       Node* sub2 = phase->transform( new (phase->C) SubINode(in1, in21) );
 175       Node* neg_c0 = phase->intcon(- tcon->get_con());
 176       return new (phase->C) AddINode(sub2, neg_c0);
 177     }
 178   }
 179 
 180   const Type *t1 = phase->type( in1 );
 181   if( t1 == Type::TOP ) return NULL;
 182 
 183 #ifdef ASSERT
 184   // Check for dead loop
 185   if( ( op2 == Op_AddI || op2 == Op_SubI ) &&
 186       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 187         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 188     assert(false, "dead loop in SubINode::Ideal");
 189 #endif
 190 
 191   // Convert "x - (x+y)" into "-y"
 192   if( op2 == Op_AddI &&
 193       phase->eqv( in1, in2->in(1) ) )
 194     return new (phase->C) SubINode( phase->intcon(0),in2->in(2));
 195   // Convert "(x-y) - x" into "-y"
 196   if( op1 == Op_SubI &&
 197       phase->eqv( in1->in(1), in2 ) )
 198     return new (phase->C) SubINode( phase->intcon(0),in1->in(2));
 199   // Convert "x - (y+x)" into "-y"
 200   if( op2 == Op_AddI &&
 201       phase->eqv( in1, in2->in(2) ) )
 202     return new (phase->C) SubINode( phase->intcon(0),in2->in(1));
 203 
 204   // Convert "0 - (x-y)" into "y-x"
 205   if( t1 == TypeInt::ZERO && op2 == Op_SubI )
 206     return new (phase->C) SubINode( in2->in(2), in2->in(1) );
 207 
 208   // Convert "0 - (x+con)" into "-con-x"
 209   jint con;
 210   if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
 211       (con = in2->in(2)->find_int_con(0)) != 0 )
 212     return new (phase->C) SubINode( phase->intcon(-con), in2->in(1) );
 213 
 214   // Convert "(X+A) - (X+B)" into "A - B"
 215   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
 216     return new (phase->C) SubINode( in1->in(2), in2->in(2) );
 217 
 218   // Convert "(A+X) - (B+X)" into "A - B"
 219   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
 220     return new (phase->C) SubINode( in1->in(1), in2->in(1) );
 221 
 222   // Convert "(A+X) - (X+B)" into "A - B"
 223   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
 224     return new (phase->C) SubINode( in1->in(1), in2->in(2) );
 225 
 226   // Convert "(X+A) - (B+X)" into "A - B"
 227   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
 228     return new (phase->C) SubINode( in1->in(2), in2->in(1) );
 229 
 230   // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
 231   // nicer to optimize than subtract.
 232   if( op2 == Op_SubI && in2->outcnt() == 1) {
 233     Node *add1 = phase->transform( new (phase->C) AddINode( in1, in2->in(2) ) );
 234     return new (phase->C) SubINode( add1, in2->in(1) );
 235   }
 236 
 237   return NULL;
 238 }
 239 
 240 //------------------------------sub--------------------------------------------
 241 // A subtract node differences it's two inputs.
 242 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
 243   const TypeInt *r0 = t1->is_int(); // Handy access
 244   const TypeInt *r1 = t2->is_int();
 245   int32 lo = r0->_lo - r1->_hi;
 246   int32 hi = r0->_hi - r1->_lo;
 247 
 248   // We next check for 32-bit overflow.
 249   // If that happens, we just assume all integers are possible.
 250   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 251        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 252       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 253        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 254     return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 255   else                          // Overflow; assume all integers
 256     return TypeInt::INT;
 257 }
 258 
 259 //=============================================================================
 260 //------------------------------Ideal------------------------------------------
 261 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 262   Node *in1 = in(1);
 263   Node *in2 = in(2);
 264   uint op1 = in1->Opcode();
 265   uint op2 = in2->Opcode();
 266 
 267 #ifdef ASSERT
 268   // Check for dead loop
 269   if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
 270       ( op1 == Op_AddL || op1 == Op_SubL ) &&
 271       ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
 272         phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1  ) ) )
 273     assert(false, "dead loop in SubLNode::Ideal");
 274 #endif
 275 
 276   if( phase->type( in2 ) == Type::TOP ) return NULL;
 277   const TypeLong *i = phase->type( in2 )->isa_long();
 278   // Convert "x-c0" into "x+ -c0".
 279   if( i &&                      // Might be bottom or top...
 280       i->is_con() )
 281     return new (phase->C) AddLNode(in1, phase->longcon(-i->get_con()));
 282 
 283   // Convert "(x+c0) - y" into (x-y) + c0"
 284   // Do not collapse (x+c0)-y if "+" is a loop increment or
 285   // if "y" is a loop induction variable.
 286   if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
 287     Node *in11 = in1->in(1);
 288     const Type *tadd = phase->type( in1->in(2) );
 289     if( tadd->singleton() && tadd != Type::TOP ) {
 290       Node *sub2 = phase->transform( new (phase->C) SubLNode( in11, in2 ));
 291       return new (phase->C) AddLNode( sub2, in1->in(2) );
 292     }
 293   }
 294 
 295   // Convert "x - (y+c0)" into "(x-y) - c0"
 296   // Need the same check as in above optimization but reversed.
 297   if (op2 == Op_AddL && ok_to_convert(in2, in1)) {
 298     Node* in21 = in2->in(1);
 299     Node* in22 = in2->in(2);
 300     const TypeLong* tcon = phase->type(in22)->isa_long();
 301     if (tcon != NULL && tcon->is_con()) {
 302       Node* sub2 = phase->transform( new (phase->C) SubLNode(in1, in21) );
 303       Node* neg_c0 = phase->longcon(- tcon->get_con());
 304       return new (phase->C) AddLNode(sub2, neg_c0);
 305     }
 306   }
 307 
 308   const Type *t1 = phase->type( in1 );
 309   if( t1 == Type::TOP ) return NULL;
 310 
 311 #ifdef ASSERT
 312   // Check for dead loop
 313   if( ( op2 == Op_AddL || op2 == Op_SubL ) &&
 314       ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
 315         phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
 316     assert(false, "dead loop in SubLNode::Ideal");
 317 #endif
 318 
 319   // Convert "x - (x+y)" into "-y"
 320   if( op2 == Op_AddL &&
 321       phase->eqv( in1, in2->in(1) ) )
 322     return new (phase->C) SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2));
 323   // Convert "x - (y+x)" into "-y"
 324   if( op2 == Op_AddL &&
 325       phase->eqv( in1, in2->in(2) ) )
 326     return new (phase->C) SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1));
 327 
 328   // Convert "0 - (x-y)" into "y-x"
 329   if( phase->type( in1 ) == TypeLong::ZERO && op2 == Op_SubL )
 330     return new (phase->C) SubLNode( in2->in(2), in2->in(1) );
 331 
 332   // Convert "(X+A) - (X+B)" into "A - B"
 333   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
 334     return new (phase->C) SubLNode( in1->in(2), in2->in(2) );
 335 
 336   // Convert "(A+X) - (B+X)" into "A - B"
 337   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
 338     return new (phase->C) SubLNode( in1->in(1), in2->in(1) );
 339 
 340   // Convert "A-(B-C)" into (A+C)-B"
 341   if( op2 == Op_SubL && in2->outcnt() == 1) {
 342     Node *add1 = phase->transform( new (phase->C) AddLNode( in1, in2->in(2) ) );
 343     return new (phase->C) SubLNode( add1, in2->in(1) );
 344   }
 345 
 346   return NULL;
 347 }
 348 
 349 //------------------------------sub--------------------------------------------
 350 // A subtract node differences it's two inputs.
 351 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
 352   const TypeLong *r0 = t1->is_long(); // Handy access
 353   const TypeLong *r1 = t2->is_long();
 354   jlong lo = r0->_lo - r1->_hi;
 355   jlong hi = r0->_hi - r1->_lo;
 356 
 357   // We next check for 32-bit overflow.
 358   // If that happens, we just assume all integers are possible.
 359   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 360        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 361       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 362        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 363     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 364   else                          // Overflow; assume all integers
 365     return TypeLong::LONG;
 366 }
 367 
 368 //=============================================================================
 369 //------------------------------Value------------------------------------------
 370 // A subtract node differences its two inputs.
 371 const Type *SubFPNode::Value( PhaseTransform *phase ) const {
 372   const Node* in1 = in(1);
 373   const Node* in2 = in(2);
 374   // Either input is TOP ==> the result is TOP
 375   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 376   if( t1 == Type::TOP ) return Type::TOP;
 377   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 378   if( t2 == Type::TOP ) return Type::TOP;
 379 
 380   // if both operands are infinity of same sign, the result is NaN; do
 381   // not replace with zero
 382   if( (t1->is_finite() && t2->is_finite()) ) {
 383     if( phase->eqv(in1, in2) ) return add_id();
 384   }
 385 
 386   // Either input is BOTTOM ==> the result is the local BOTTOM
 387   const Type *bot = bottom_type();
 388   if( (t1 == bot) || (t2 == bot) ||
 389       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 390     return bot;
 391 
 392   return sub(t1,t2);            // Local flavor of type subtraction
 393 }
 394 
 395 
 396 //=============================================================================
 397 //------------------------------Ideal------------------------------------------
 398 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 399   const Type *t2 = phase->type( in(2) );
 400   // Convert "x-c0" into "x+ -c0".
 401   if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
 402     // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
 403   }
 404 
 405   // Not associative because of boundary conditions (infinity)
 406   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 407     // Convert "x - (x+y)" into "-y"
 408     if( in(2)->is_Add() &&
 409         phase->eqv(in(1),in(2)->in(1) ) )
 410       return new (phase->C) SubFNode( phase->makecon(TypeF::ZERO),in(2)->in(2));
 411   }
 412 
 413   // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
 414   // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
 415   //if( phase->type(in(1)) == TypeF::ZERO )
 416   //return new (phase->C, 2) NegFNode(in(2));
 417 
 418   return NULL;
 419 }
 420 
 421 //------------------------------sub--------------------------------------------
 422 // A subtract node differences its two inputs.
 423 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
 424   // no folding if one of operands is infinity or NaN, do not do constant folding
 425   if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
 426     return TypeF::make( t1->getf() - t2->getf() );
 427   }
 428   else if( g_isnan(t1->getf()) ) {
 429     return t1;
 430   }
 431   else if( g_isnan(t2->getf()) ) {
 432     return t2;
 433   }
 434   else {
 435     return Type::FLOAT;
 436   }
 437 }
 438 
 439 //=============================================================================
 440 //------------------------------Ideal------------------------------------------
 441 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 442   const Type *t2 = phase->type( in(2) );
 443   // Convert "x-c0" into "x+ -c0".
 444   if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
 445     // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
 446   }
 447 
 448   // Not associative because of boundary conditions (infinity)
 449   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 450     // Convert "x - (x+y)" into "-y"
 451     if( in(2)->is_Add() &&
 452         phase->eqv(in(1),in(2)->in(1) ) )
 453       return new (phase->C) SubDNode( phase->makecon(TypeD::ZERO),in(2)->in(2));
 454   }
 455 
 456   // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
 457   // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
 458   //if( phase->type(in(1)) == TypeD::ZERO )
 459   //return new (phase->C, 2) NegDNode(in(2));
 460 
 461   return NULL;
 462 }
 463 
 464 //------------------------------sub--------------------------------------------
 465 // A subtract node differences its two inputs.
 466 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
 467   // no folding if one of operands is infinity or NaN, do not do constant folding
 468   if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
 469     return TypeD::make( t1->getd() - t2->getd() );
 470   }
 471   else if( g_isnan(t1->getd()) ) {
 472     return t1;
 473   }
 474   else if( g_isnan(t2->getd()) ) {
 475     return t2;
 476   }
 477   else {
 478     return Type::DOUBLE;
 479   }
 480 }
 481 
 482 //=============================================================================
 483 //------------------------------Idealize---------------------------------------
 484 // Unlike SubNodes, compare must still flatten return value to the
 485 // range -1, 0, 1.
 486 // And optimizations like those for (X + Y) - X fail if overflow happens.
 487 Node *CmpNode::Identity( PhaseTransform *phase ) {
 488   return this;
 489 }
 490 
 491 //=============================================================================
 492 //------------------------------cmp--------------------------------------------
 493 // Simplify a CmpI (compare 2 integers) node, based on local information.
 494 // If both inputs are constants, compare them.
 495 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 496   const TypeInt *r0 = t1->is_int(); // Handy access
 497   const TypeInt *r1 = t2->is_int();
 498 
 499   if( r0->_hi < r1->_lo )       // Range is always low?
 500     return TypeInt::CC_LT;
 501   else if( r0->_lo > r1->_hi )  // Range is always high?
 502     return TypeInt::CC_GT;
 503 
 504   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 505     assert(r0->get_con() == r1->get_con(), "must be equal");
 506     return TypeInt::CC_EQ;      // Equal results.
 507   } else if( r0->_hi == r1->_lo ) // Range is never high?
 508     return TypeInt::CC_LE;
 509   else if( r0->_lo == r1->_hi ) // Range is never low?
 510     return TypeInt::CC_GE;
 511   return TypeInt::CC;           // else use worst case results
 512 }
 513 
 514 // Simplify a CmpU (compare 2 integers) node, based on local information.
 515 // If both inputs are constants, compare them.
 516 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 517   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 518 
 519   // comparing two unsigned ints
 520   const TypeInt *r0 = t1->is_int();   // Handy access
 521   const TypeInt *r1 = t2->is_int();
 522 
 523   // Current installed version
 524   // Compare ranges for non-overlap
 525   juint lo0 = r0->_lo;
 526   juint hi0 = r0->_hi;
 527   juint lo1 = r1->_lo;
 528   juint hi1 = r1->_hi;
 529 
 530   // If either one has both negative and positive values,
 531   // it therefore contains both 0 and -1, and since [0..-1] is the
 532   // full unsigned range, the type must act as an unsigned bottom.
 533   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 534   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 535 
 536   if (bot0 || bot1) {
 537     // All unsigned values are LE -1 and GE 0.
 538     if (lo0 == 0 && hi0 == 0) {
 539       return TypeInt::CC_LE;            //   0 <= bot
 540     } else if (lo1 == 0 && hi1 == 0) {
 541       return TypeInt::CC_GE;            // bot >= 0
 542     }
 543   } else {
 544     // We can use ranges of the form [lo..hi] if signs are the same.
 545     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 546     // results are reversed, '-' > '+' for unsigned compare
 547     if (hi0 < lo1) {
 548       return TypeInt::CC_LT;            // smaller
 549     } else if (lo0 > hi1) {
 550       return TypeInt::CC_GT;            // greater
 551     } else if (hi0 == lo1 && lo0 == hi1) {
 552       return TypeInt::CC_EQ;            // Equal results
 553     } else if (lo0 >= hi1) {
 554       return TypeInt::CC_GE;
 555     } else if (hi0 <= lo1) {
 556       // Check for special case in Hashtable::get.  (See below.)
 557       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 558         return TypeInt::CC_LT;
 559       return TypeInt::CC_LE;
 560     }
 561   }
 562   // Check for special case in Hashtable::get - the hash index is
 563   // mod'ed to the table size so the following range check is useless.
 564   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 565   // to be positive.
 566   // (This is a gross hack, since the sub method never
 567   // looks at the structure of the node in any other case.)
 568   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 569     return TypeInt::CC_LT;
 570   return TypeInt::CC;                   // else use worst case results
 571 }
 572 
 573 bool CmpUNode::is_index_range_check() const {
 574   // Check for the "(X ModI Y) CmpU Y" shape
 575   return (in(1)->Opcode() == Op_ModI &&
 576           in(1)->in(2)->eqv_uncast(in(2)));
 577 }
 578 
 579 //------------------------------Idealize---------------------------------------
 580 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 581   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 582     switch (in(1)->Opcode()) {
 583     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 584       return new (phase->C) CmpLNode(in(1)->in(1),in(1)->in(2));
 585     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 586       return new (phase->C) CmpFNode(in(1)->in(1),in(1)->in(2));
 587     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 588       return new (phase->C) CmpDNode(in(1)->in(1),in(1)->in(2));
 589     //case Op_SubI:
 590       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 591       // can be turned into (x <?> y).
 592       // This is handled (with more general cases) by Ideal_sub_algebra.
 593     }
 594   }
 595   return NULL;                  // No change
 596 }
 597 
 598 
 599 //=============================================================================
 600 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 601 // If both inputs are constants, compare them.
 602 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 603   const TypeLong *r0 = t1->is_long(); // Handy access
 604   const TypeLong *r1 = t2->is_long();
 605 
 606   if( r0->_hi < r1->_lo )       // Range is always low?
 607     return TypeInt::CC_LT;
 608   else if( r0->_lo > r1->_hi )  // Range is always high?
 609     return TypeInt::CC_GT;
 610 
 611   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 612     assert(r0->get_con() == r1->get_con(), "must be equal");
 613     return TypeInt::CC_EQ;      // Equal results.
 614   } else if( r0->_hi == r1->_lo ) // Range is never high?
 615     return TypeInt::CC_LE;
 616   else if( r0->_lo == r1->_hi ) // Range is never low?
 617     return TypeInt::CC_GE;
 618   return TypeInt::CC;           // else use worst case results
 619 }
 620 
 621 //=============================================================================
 622 //------------------------------sub--------------------------------------------
 623 // Simplify an CmpP (compare 2 pointers) node, based on local information.
 624 // If both inputs are constants, compare them.
 625 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
 626   const TypePtr *r0 = t1->is_ptr(); // Handy access
 627   const TypePtr *r1 = t2->is_ptr();
 628 
 629   // Undefined inputs makes for an undefined result
 630   if( TypePtr::above_centerline(r0->_ptr) ||
 631       TypePtr::above_centerline(r1->_ptr) )
 632     return Type::TOP;
 633 
 634   if (r0 == r1 && r0->singleton()) {
 635     // Equal pointer constants (klasses, nulls, etc.)
 636     return TypeInt::CC_EQ;
 637   }
 638 
 639   // See if it is 2 unrelated classes.
 640   const TypeOopPtr* p0 = r0->isa_oopptr();
 641   const TypeOopPtr* p1 = r1->isa_oopptr();
 642   if (p0 && p1) {
 643     Node* in1 = in(1)->uncast();
 644     Node* in2 = in(2)->uncast();
 645     AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
 646     AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
 647     if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
 648       return TypeInt::CC_GT;  // different pointers
 649     }
 650     ciKlass* klass0 = p0->klass();
 651     bool    xklass0 = p0->klass_is_exact();
 652     ciKlass* klass1 = p1->klass();
 653     bool    xklass1 = p1->klass_is_exact();
 654     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 655     if (klass0 && klass1 &&
 656         kps != 1 &&             // both or neither are klass pointers
 657         klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
 658         klass1->is_loaded() && !klass1->is_interface() &&
 659         (!klass0->is_obj_array_klass() ||
 660          !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
 661         (!klass1->is_obj_array_klass() ||
 662          !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
 663       bool unrelated_classes = false;
 664       // See if neither subclasses the other, or if the class on top
 665       // is precise.  In either of these cases, the compare is known
 666       // to fail if at least one of the pointers is provably not null.
 667       if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
 668         // Do nothing; we know nothing for imprecise types
 669       } else if (klass0->is_subtype_of(klass1)) {
 670         // If klass1's type is PRECISE, then classes are unrelated.
 671         unrelated_classes = xklass1;
 672       } else if (klass1->is_subtype_of(klass0)) {
 673         // If klass0's type is PRECISE, then classes are unrelated.
 674         unrelated_classes = xklass0;
 675       } else {                  // Neither subtypes the other
 676         unrelated_classes = true;
 677       }
 678       if (unrelated_classes) {
 679         // The oops classes are known to be unrelated. If the joined PTRs of
 680         // two oops is not Null and not Bottom, then we are sure that one
 681         // of the two oops is non-null, and the comparison will always fail.
 682         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 683         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 684           return TypeInt::CC_GT;
 685         }
 686       }
 687     }
 688   }
 689 
 690   // Known constants can be compared exactly
 691   // Null can be distinguished from any NotNull pointers
 692   // Unknown inputs makes an unknown result
 693   if( r0->singleton() ) {
 694     intptr_t bits0 = r0->get_con();
 695     if( r1->singleton() )
 696       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 697     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 698   } else if( r1->singleton() ) {
 699     intptr_t bits1 = r1->get_con();
 700     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 701   } else
 702     return TypeInt::CC;
 703 }
 704 
 705 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
 706   // Return the klass node for
 707   //   LoadP(AddP(foo:Klass, #java_mirror))
 708   //   or NULL if not matching.
 709   if (n->Opcode() != Op_LoadP) return NULL;
 710 
 711   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 712   if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;
 713 
 714   Node* adr = n->in(MemNode::Address);
 715   intptr_t off = 0;
 716   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
 717   if (k == NULL)  return NULL;
 718   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
 719   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL;
 720 
 721   // We've found the klass node of a Java mirror load.
 722   return k;
 723 }
 724 
 725 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
 726   // for ConP(Foo.class) return ConP(Foo.klass)
 727   // otherwise return NULL
 728   if (!n->is_Con()) return NULL;
 729 
 730   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 731   if (!tp) return NULL;
 732 
 733   ciType* mirror_type = tp->java_mirror_type();
 734   // TypeInstPtr::java_mirror_type() returns non-NULL for compile-
 735   // time Class constants only.
 736   if (!mirror_type) return NULL;
 737 
 738   // x.getClass() == int.class can never be true (for all primitive types)
 739   // Return a ConP(NULL) node for this case.
 740   if (mirror_type->is_classless()) {
 741     return phase->makecon(TypePtr::NULL_PTR);
 742   }
 743 
 744   // return the ConP(Foo.klass)
 745   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
 746   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass()));
 747 }
 748 
 749 //------------------------------Ideal------------------------------------------
 750 // Normalize comparisons between Java mirror loads to compare the klass instead.
 751 //
 752 // Also check for the case of comparing an unknown klass loaded from the primary
 753 // super-type array vs a known klass with no subtypes.  This amounts to
 754 // checking to see an unknown klass subtypes a known klass with no subtypes;
 755 // this only happens on an exact match.  We can shorten this test by 1 load.
 756 Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 757   // Normalize comparisons between Java mirrors into comparisons of the low-
 758   // level klass, where a dependent load could be shortened.
 759   //
 760   // The new pattern has a nice effect of matching the same pattern used in the
 761   // fast path of instanceof/checkcast/Class.isInstance(), which allows
 762   // redundant exact type check be optimized away by GVN.
 763   // For example, in
 764   //   if (x.getClass() == Foo.class) {
 765   //     Foo foo = (Foo) x;
 766   //     // ... use a ...
 767   //   }
 768   // a CmpPNode could be shared between if_acmpne and checkcast
 769   {
 770     Node* k1 = isa_java_mirror_load(phase, in(1));
 771     Node* k2 = isa_java_mirror_load(phase, in(2));
 772     Node* conk2 = isa_const_java_mirror(phase, in(2));
 773 
 774     if (k1 && (k2 || conk2)) {
 775       Node* lhs = k1;
 776       Node* rhs = (k2 != NULL) ? k2 : conk2;
 777       this->set_req(1, lhs);
 778       this->set_req(2, rhs);
 779       return this;
 780     }
 781   }
 782 
 783   // Constant pointer on right?
 784   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
 785   if (t2 == NULL || !t2->klass_is_exact())
 786     return NULL;
 787   // Get the constant klass we are comparing to.
 788   ciKlass* superklass = t2->klass();
 789 
 790   // Now check for LoadKlass on left.
 791   Node* ldk1 = in(1);
 792   if (ldk1->is_DecodeNKlass()) {
 793     ldk1 = ldk1->in(1);
 794     if (ldk1->Opcode() != Op_LoadNKlass )
 795       return NULL;
 796   } else if (ldk1->Opcode() != Op_LoadKlass )
 797     return NULL;
 798   // Take apart the address of the LoadKlass:
 799   Node* adr1 = ldk1->in(MemNode::Address);
 800   intptr_t con2 = 0;
 801   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
 802   if (ldk2 == NULL)
 803     return NULL;
 804   if (con2 == oopDesc::klass_offset_in_bytes()) {
 805     // We are inspecting an object's concrete class.
 806     // Short-circuit the check if the query is abstract.
 807     if (superklass->is_interface() ||
 808         superklass->is_abstract()) {
 809       // Make it come out always false:
 810       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
 811       return this;
 812     }
 813   }
 814 
 815   // Check for a LoadKlass from primary supertype array.
 816   // Any nested loadklass from loadklass+con must be from the p.s. array.
 817   if (ldk2->is_DecodeNKlass()) {
 818     // Keep ldk2 as DecodeN since it could be used in CmpP below.
 819     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
 820       return NULL;
 821   } else if (ldk2->Opcode() != Op_LoadKlass)
 822     return NULL;
 823 
 824   // Verify that we understand the situation
 825   if (con2 != (intptr_t) superklass->super_check_offset())
 826     return NULL;                // Might be element-klass loading from array klass
 827 
 828   // If 'superklass' has no subklasses and is not an interface, then we are
 829   // assured that the only input which will pass the type check is
 830   // 'superklass' itself.
 831   //
 832   // We could be more liberal here, and allow the optimization on interfaces
 833   // which have a single implementor.  This would require us to increase the
 834   // expressiveness of the add_dependency() mechanism.
 835   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
 836 
 837   // Object arrays must have their base element have no subtypes
 838   while (superklass->is_obj_array_klass()) {
 839     ciType* elem = superklass->as_obj_array_klass()->element_type();
 840     superklass = elem->as_klass();
 841   }
 842   if (superklass->is_instance_klass()) {
 843     ciInstanceKlass* ik = superklass->as_instance_klass();
 844     if (ik->has_subklass() || ik->is_interface())  return NULL;
 845     // Add a dependency if there is a chance that a subclass will be added later.
 846     if (!ik->is_final()) {
 847       phase->C->dependencies()->assert_leaf_type(ik);
 848     }
 849   }
 850 
 851   // Bypass the dependent load, and compare directly
 852   this->set_req(1,ldk2);
 853 
 854   return this;
 855 }
 856 
 857 //=============================================================================
 858 //------------------------------sub--------------------------------------------
 859 // Simplify an CmpN (compare 2 pointers) node, based on local information.
 860 // If both inputs are constants, compare them.
 861 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
 862   const TypePtr *r0 = t1->make_ptr(); // Handy access
 863   const TypePtr *r1 = t2->make_ptr();
 864 
 865   // Undefined inputs makes for an undefined result
 866   if( TypePtr::above_centerline(r0->_ptr) ||
 867       TypePtr::above_centerline(r1->_ptr) )
 868     return Type::TOP;
 869 
 870   if (r0 == r1 && r0->singleton()) {
 871     // Equal pointer constants (klasses, nulls, etc.)
 872     return TypeInt::CC_EQ;
 873   }
 874 
 875   // See if it is 2 unrelated classes.
 876   const TypeOopPtr* p0 = r0->isa_oopptr();
 877   const TypeOopPtr* p1 = r1->isa_oopptr();
 878   if (p0 && p1) {
 879     ciKlass* klass0 = p0->klass();
 880     bool    xklass0 = p0->klass_is_exact();
 881     ciKlass* klass1 = p1->klass();
 882     bool    xklass1 = p1->klass_is_exact();
 883     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 884     if (klass0 && klass1 &&
 885         kps != 1 &&             // both or neither are klass pointers
 886         !klass0->is_interface() && // do not trust interfaces
 887         !klass1->is_interface()) {
 888       bool unrelated_classes = false;
 889       // See if neither subclasses the other, or if the class on top
 890       // is precise.  In either of these cases, the compare is known
 891       // to fail if at least one of the pointers is provably not null.
 892       if (klass0->equals(klass1)) { // if types are unequal but klasses are equal
 893         // Do nothing; we know nothing for imprecise types
 894       } else if (klass0->is_subtype_of(klass1)) {
 895         // If klass1's type is PRECISE, then classes are unrelated.
 896         unrelated_classes = xklass1;
 897       } else if (klass1->is_subtype_of(klass0)) {
 898         // If klass0's type is PRECISE, then classes are unrelated.
 899         unrelated_classes = xklass0;
 900       } else {                  // Neither subtypes the other
 901         unrelated_classes = true;
 902       }
 903       if (unrelated_classes) {
 904         // The oops classes are known to be unrelated. If the joined PTRs of
 905         // two oops is not Null and not Bottom, then we are sure that one
 906         // of the two oops is non-null, and the comparison will always fail.
 907         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 908         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 909           return TypeInt::CC_GT;
 910         }
 911       }
 912     }
 913   }
 914 
 915   // Known constants can be compared exactly
 916   // Null can be distinguished from any NotNull pointers
 917   // Unknown inputs makes an unknown result
 918   if( r0->singleton() ) {
 919     intptr_t bits0 = r0->get_con();
 920     if( r1->singleton() )
 921       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 922     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 923   } else if( r1->singleton() ) {
 924     intptr_t bits1 = r1->get_con();
 925     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 926   } else
 927     return TypeInt::CC;
 928 }
 929 
 930 //------------------------------Ideal------------------------------------------
 931 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 932   return NULL;
 933 }
 934 
 935 //=============================================================================
 936 //------------------------------Value------------------------------------------
 937 // Simplify an CmpF (compare 2 floats ) node, based on local information.
 938 // If both inputs are constants, compare them.
 939 const Type *CmpFNode::Value( PhaseTransform *phase ) const {
 940   const Node* in1 = in(1);
 941   const Node* in2 = in(2);
 942   // Either input is TOP ==> the result is TOP
 943   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 944   if( t1 == Type::TOP ) return Type::TOP;
 945   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 946   if( t2 == Type::TOP ) return Type::TOP;
 947 
 948   // Not constants?  Don't know squat - even if they are the same
 949   // value!  If they are NaN's they compare to LT instead of EQ.
 950   const TypeF *tf1 = t1->isa_float_constant();
 951   const TypeF *tf2 = t2->isa_float_constant();
 952   if( !tf1 || !tf2 ) return TypeInt::CC;
 953 
 954   // This implements the Java bytecode fcmpl, so unordered returns -1.
 955   if( tf1->is_nan() || tf2->is_nan() )
 956     return TypeInt::CC_LT;
 957 
 958   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
 959   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
 960   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
 961   return TypeInt::CC_EQ;
 962 }
 963 
 964 
 965 //=============================================================================
 966 //------------------------------Value------------------------------------------
 967 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
 968 // If both inputs are constants, compare them.
 969 const Type *CmpDNode::Value( PhaseTransform *phase ) const {
 970   const Node* in1 = in(1);
 971   const Node* in2 = in(2);
 972   // Either input is TOP ==> the result is TOP
 973   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 974   if( t1 == Type::TOP ) return Type::TOP;
 975   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 976   if( t2 == Type::TOP ) return Type::TOP;
 977 
 978   // Not constants?  Don't know squat - even if they are the same
 979   // value!  If they are NaN's they compare to LT instead of EQ.
 980   const TypeD *td1 = t1->isa_double_constant();
 981   const TypeD *td2 = t2->isa_double_constant();
 982   if( !td1 || !td2 ) return TypeInt::CC;
 983 
 984   // This implements the Java bytecode dcmpl, so unordered returns -1.
 985   if( td1->is_nan() || td2->is_nan() )
 986     return TypeInt::CC_LT;
 987 
 988   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
 989   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
 990   assert( td1->_d == td2->_d, "do not understand FP behavior" );
 991   return TypeInt::CC_EQ;
 992 }
 993 
 994 //------------------------------Ideal------------------------------------------
 995 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 996   // Check if we can change this to a CmpF and remove a ConvD2F operation.
 997   // Change  (CMPD (F2D (float)) (ConD value))
 998   // To      (CMPF      (float)  (ConF value))
 999   // Valid when 'value' does not lose precision as a float.
1000   // Benefits: eliminates conversion, does not require 24-bit mode
1001 
1002   // NaNs prevent commuting operands.  This transform works regardless of the
1003   // order of ConD and ConvF2D inputs by preserving the original order.
1004   int idx_f2d = 1;              // ConvF2D on left side?
1005   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1006     idx_f2d = 2;                // No, swap to check for reversed args
1007   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1008 
1009   if( ConvertCmpD2CmpF &&
1010       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1011       in(idx_con)->Opcode() == Op_ConD ) {
1012     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1013     double t2_value_as_double = t2->_d;
1014     float  t2_value_as_float  = (float)t2_value_as_double;
1015     if( t2_value_as_double == (double)t2_value_as_float ) {
1016       // Test value can be represented as a float
1017       // Eliminate the conversion to double and create new comparison
1018       Node *new_in1 = in(idx_f2d)->in(1);
1019       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1020       if( idx_f2d != 1 ) {      // Must flip args to match original order
1021         Node *tmp = new_in1;
1022         new_in1 = new_in2;
1023         new_in2 = tmp;
1024       }
1025       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1026         ? new (phase->C) CmpF3Node( new_in1, new_in2 )
1027         : new (phase->C) CmpFNode ( new_in1, new_in2 ) ;
1028       return new_cmp;           // Changed to CmpFNode
1029     }
1030     // Testing value required the precision of a double
1031   }
1032   return NULL;                  // No change
1033 }
1034 
1035 
1036 //=============================================================================
1037 //------------------------------cc2logical-------------------------------------
1038 // Convert a condition code type to a logical type
1039 const Type *BoolTest::cc2logical( const Type *CC ) const {
1040   if( CC == Type::TOP ) return Type::TOP;
1041   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1042   const TypeInt *ti = CC->is_int();
1043   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1044     // Match low order 2 bits
1045     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1046     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1047     return TypeInt::make(tmp);       // Boolean result
1048   }
1049 
1050   if( CC == TypeInt::CC_GE ) {
1051     if( _test == ge ) return TypeInt::ONE;
1052     if( _test == lt ) return TypeInt::ZERO;
1053   }
1054   if( CC == TypeInt::CC_LE ) {
1055     if( _test == le ) return TypeInt::ONE;
1056     if( _test == gt ) return TypeInt::ZERO;
1057   }
1058 
1059   return TypeInt::BOOL;
1060 }
1061 
1062 //------------------------------dump_spec-------------------------------------
1063 // Print special per-node info
1064 #ifndef PRODUCT
1065 void BoolTest::dump_on(outputStream *st) const {
1066   const char *msg[] = {"eq","gt","??","lt","ne","le","??","ge"};
1067   st->print(msg[_test]);
1068 }
1069 #endif
1070 
1071 //=============================================================================
1072 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1073 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1074 
1075 //------------------------------operator==-------------------------------------
1076 uint BoolNode::cmp( const Node &n ) const {
1077   const BoolNode *b = (const BoolNode *)&n; // Cast up
1078   return (_test._test == b->_test._test);
1079 }
1080 
1081 //-------------------------------make_predicate--------------------------------
1082 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1083   if (test_value->is_Con())   return test_value;
1084   if (test_value->is_Bool())  return test_value;
1085   Compile* C = phase->C;
1086   if (test_value->is_CMove() &&
1087       test_value->in(CMoveNode::Condition)->is_Bool()) {
1088     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1089     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1090     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1091     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1092       return bol;
1093     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1094       return phase->transform( bol->negate(phase) );
1095     }
1096     // Else fall through.  The CMove gets in the way of the test.
1097     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1098   }
1099   Node* cmp = new (C) CmpINode(test_value, phase->intcon(0));
1100   cmp = phase->transform(cmp);
1101   Node* bol = new (C) BoolNode(cmp, BoolTest::ne);
1102   return phase->transform(bol);
1103 }
1104 
1105 //--------------------------------as_int_value---------------------------------
1106 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1107   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1108   Node* cmov = CMoveNode::make(phase->C, NULL, this,
1109                                phase->intcon(0), phase->intcon(1),
1110                                TypeInt::BOOL);
1111   return phase->transform(cmov);
1112 }
1113 
1114 //----------------------------------negate-------------------------------------
1115 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1116   Compile* C = phase->C;
1117   return new (C) BoolNode(in(1), _test.negate());
1118 }
1119 
1120 
1121 //------------------------------Ideal------------------------------------------
1122 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1123   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1124   // This moves the constant to the right.  Helps value-numbering.
1125   Node *cmp = in(1);
1126   if( !cmp->is_Sub() ) return NULL;
1127   int cop = cmp->Opcode();
1128   if( cop == Op_FastLock || cop == Op_FastUnlock ) return NULL;
1129   Node *cmp1 = cmp->in(1);
1130   Node *cmp2 = cmp->in(2);
1131   if( !cmp1 ) return NULL;
1132 
1133   // Constant on left?
1134   Node *con = cmp1;
1135   uint op2 = cmp2->Opcode();
1136   // Move constants to the right of compare's to canonicalize.
1137   // Do not muck with Opaque1 nodes, as this indicates a loop
1138   // guard that cannot change shape.
1139   if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 &&
1140       // Because of NaN's, CmpD and CmpF are not commutative
1141       cop != Op_CmpD && cop != Op_CmpF &&
1142       // Protect against swapping inputs to a compare when it is used by a
1143       // counted loop exit, which requires maintaining the loop-limit as in(2)
1144       !is_counted_loop_exit_test() ) {
1145     // Ok, commute the constant to the right of the cmp node.
1146     // Clone the Node, getting a new Node of the same class
1147     cmp = cmp->clone();
1148     // Swap inputs to the clone
1149     cmp->swap_edges(1, 2);
1150     cmp = phase->transform( cmp );
1151     return new (phase->C) BoolNode( cmp, _test.commute() );
1152   }
1153 
1154   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1155   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1156   // test instead.
1157   int cmp1_op = cmp1->Opcode();
1158   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1159   if (cmp2_type == NULL)  return NULL;
1160   Node* j_xor = cmp1;
1161   if( cmp2_type == TypeInt::ZERO &&
1162       cmp1_op == Op_XorI &&
1163       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1164       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1165       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1166       (_test._test == BoolTest::eq ||
1167        _test._test == BoolTest::ne) ) {
1168     Node *ncmp = phase->transform(new (phase->C) CmpINode(j_xor->in(1),cmp2));
1169     return new (phase->C) BoolNode( ncmp, _test.negate() );
1170   }
1171 
1172   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1173   // This is a standard idiom for branching on a boolean value.
1174   Node *c2b = cmp1;
1175   if( cmp2_type == TypeInt::ZERO &&
1176       cmp1_op == Op_Conv2B &&
1177       (_test._test == BoolTest::eq ||
1178        _test._test == BoolTest::ne) ) {
1179     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1180        ? (Node*)new (phase->C) CmpINode(c2b->in(1),cmp2)
1181        : (Node*)new (phase->C) CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1182     );
1183     return new (phase->C) BoolNode( ncmp, _test._test );
1184   }
1185 
1186   // Comparing a SubI against a zero is equal to comparing the SubI
1187   // arguments directly.  This only works for eq and ne comparisons
1188   // due to possible integer overflow.
1189   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1190         (cop == Op_CmpI) &&
1191         (cmp1->Opcode() == Op_SubI) &&
1192         ( cmp2_type == TypeInt::ZERO ) ) {
1193     Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(1),cmp1->in(2)));
1194     return new (phase->C) BoolNode( ncmp, _test._test );
1195   }
1196 
1197   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1198   // most general case because negating 0x80000000 does nothing.  Needed for
1199   // the CmpF3/SubI/CmpI idiom.
1200   if( cop == Op_CmpI &&
1201       cmp1->Opcode() == Op_SubI &&
1202       cmp2_type == TypeInt::ZERO &&
1203       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1204       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1205     Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(2),cmp2));
1206     return new (phase->C) BoolNode( ncmp, _test.commute() );
1207   }
1208 
1209   //  The transformation below is not valid for either signed or unsigned
1210   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1211   //  This transformation can be resurrected when we are able to
1212   //  make inferences about the range of values being subtracted from
1213   //  (or added to) relative to the wraparound point.
1214   //
1215   //    // Remove +/-1's if possible.
1216   //    // "X <= Y-1" becomes "X <  Y"
1217   //    // "X+1 <= Y" becomes "X <  Y"
1218   //    // "X <  Y+1" becomes "X <= Y"
1219   //    // "X-1 <  Y" becomes "X <= Y"
1220   //    // Do not this to compares off of the counted-loop-end.  These guys are
1221   //    // checking the trip counter and they want to use the post-incremented
1222   //    // counter.  If they use the PRE-incremented counter, then the counter has
1223   //    // to be incremented in a private block on a loop backedge.
1224   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1225   //      return NULL;
1226   //  #ifndef PRODUCT
1227   //    // Do not do this in a wash GVN pass during verification.
1228   //    // Gets triggered by too many simple optimizations to be bothered with
1229   //    // re-trying it again and again.
1230   //    if( !phase->allow_progress() ) return NULL;
1231   //  #endif
1232   //    // Not valid for unsigned compare because of corner cases in involving zero.
1233   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1234   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1235   //    // "0 <=u Y" is always true).
1236   //    if( cmp->Opcode() == Op_CmpU ) return NULL;
1237   //    int cmp2_op = cmp2->Opcode();
1238   //    if( _test._test == BoolTest::le ) {
1239   //      if( cmp1_op == Op_AddI &&
1240   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1241   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1242   //      else if( cmp2_op == Op_AddI &&
1243   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1244   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1245   //    } else if( _test._test == BoolTest::lt ) {
1246   //      if( cmp1_op == Op_AddI &&
1247   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1248   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1249   //      else if( cmp2_op == Op_AddI &&
1250   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1251   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1252   //    }
1253 
1254   return NULL;
1255 }
1256 
1257 //------------------------------Value------------------------------------------
1258 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
1259 // based on local information.   If the input is constant, do it.
1260 const Type *BoolNode::Value( PhaseTransform *phase ) const {
1261   return _test.cc2logical( phase->type( in(1) ) );
1262 }
1263 
1264 //------------------------------dump_spec--------------------------------------
1265 // Dump special per-node info
1266 #ifndef PRODUCT
1267 void BoolNode::dump_spec(outputStream *st) const {
1268   st->print("[");
1269   _test.dump_on(st);
1270   st->print("]");
1271 }
1272 #endif
1273 
1274 //------------------------------is_counted_loop_exit_test--------------------------------------
1275 // Returns true if node is used by a counted loop node.
1276 bool BoolNode::is_counted_loop_exit_test() {
1277   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
1278     Node* use = fast_out(i);
1279     if (use->is_CountedLoopEnd()) {
1280       return true;
1281     }
1282   }
1283   return false;
1284 }
1285 
1286 //=============================================================================
1287 //------------------------------Value------------------------------------------
1288 // Compute sqrt
1289 const Type *SqrtDNode::Value( PhaseTransform *phase ) const {
1290   const Type *t1 = phase->type( in(1) );
1291   if( t1 == Type::TOP ) return Type::TOP;
1292   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1293   double d = t1->getd();
1294   if( d < 0.0 ) return Type::DOUBLE;
1295   return TypeD::make( sqrt( d ) );
1296 }
1297 
1298 //=============================================================================
1299 //------------------------------Value------------------------------------------
1300 // Compute cos
1301 const Type *CosDNode::Value( PhaseTransform *phase ) const {
1302   const Type *t1 = phase->type( in(1) );
1303   if( t1 == Type::TOP ) return Type::TOP;
1304   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1305   double d = t1->getd();
1306   return TypeD::make( StubRoutines::intrinsic_cos( d ) );
1307 }
1308 
1309 //=============================================================================
1310 //------------------------------Value------------------------------------------
1311 // Compute sin
1312 const Type *SinDNode::Value( PhaseTransform *phase ) const {
1313   const Type *t1 = phase->type( in(1) );
1314   if( t1 == Type::TOP ) return Type::TOP;
1315   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1316   double d = t1->getd();
1317   return TypeD::make( StubRoutines::intrinsic_sin( d ) );
1318 }
1319 
1320 //=============================================================================
1321 //------------------------------Value------------------------------------------
1322 // Compute tan
1323 const Type *TanDNode::Value( PhaseTransform *phase ) const {
1324   const Type *t1 = phase->type( in(1) );
1325   if( t1 == Type::TOP ) return Type::TOP;
1326   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1327   double d = t1->getd();
1328   return TypeD::make( StubRoutines::intrinsic_tan( d ) );
1329 }
1330 
1331 //=============================================================================
1332 //------------------------------Value------------------------------------------
1333 // Compute log
1334 const Type *LogDNode::Value( PhaseTransform *phase ) const {
1335   const Type *t1 = phase->type( in(1) );
1336   if( t1 == Type::TOP ) return Type::TOP;
1337   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1338   double d = t1->getd();
1339   return TypeD::make( StubRoutines::intrinsic_log( d ) );
1340 }
1341 
1342 //=============================================================================
1343 //------------------------------Value------------------------------------------
1344 // Compute log10
1345 const Type *Log10DNode::Value( PhaseTransform *phase ) const {
1346   const Type *t1 = phase->type( in(1) );
1347   if( t1 == Type::TOP ) return Type::TOP;
1348   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1349   double d = t1->getd();
1350   return TypeD::make( StubRoutines::intrinsic_log10( d ) );
1351 }
1352 
1353 //=============================================================================
1354 //------------------------------Value------------------------------------------
1355 // Compute exp
1356 const Type *ExpDNode::Value( PhaseTransform *phase ) const {
1357   const Type *t1 = phase->type( in(1) );
1358   if( t1 == Type::TOP ) return Type::TOP;
1359   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1360   double d = t1->getd();
1361   return TypeD::make( StubRoutines::intrinsic_exp( d ) );
1362 }
1363 
1364 
1365 //=============================================================================
1366 //------------------------------Value------------------------------------------
1367 // Compute pow
1368 const Type *PowDNode::Value( PhaseTransform *phase ) const {
1369   const Type *t1 = phase->type( in(1) );
1370   if( t1 == Type::TOP ) return Type::TOP;
1371   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1372   const Type *t2 = phase->type( in(2) );
1373   if( t2 == Type::TOP ) return Type::TOP;
1374   if( t2->base() != Type::DoubleCon ) return Type::DOUBLE;
1375   double d1 = t1->getd();
1376   double d2 = t2->getd();
1377   return TypeD::make( StubRoutines::intrinsic_pow( d1, d2 ) );
1378 }