1 /*
   2  * Copyright (c) 1997, 2014, 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( 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_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(PhaseTransform *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 (phase->C) 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 (phase->C) SubINode( in1->in(1), in2 ));
 172       return new (phase->C) 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 (phase->C) SubINode(in1, in21) );
 185       Node* neg_c0 = phase->intcon(- tcon->get_con());
 186       return new (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) AddINode( in1, in2->in(2) ) );
 244     return new (phase->C) 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 lo = r0->_lo - r1->_hi;
 256   int32 hi = 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 (phase->C) 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 (phase->C) SubLNode( in11, in2 ));
 301       return new (phase->C) 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 (phase->C) SubLNode(in1, in21) );
 313       Node* neg_c0 = phase->longcon(- tcon->get_con());
 314       return new (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) 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 (phase->C) AddLNode( in1, in2->in(2) ) );
 353     return new (phase->C) 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 = r0->_lo - r1->_hi;
 365   jlong hi = 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( PhaseTransform *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 (phase->C) 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 (phase->C) 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( PhaseTransform *phase ) {
 498   return this;
 499 }
 500 
 501 //=============================================================================
 502 //------------------------------cmp--------------------------------------------
 503 // Simplify a CmpI (compare 2 integers) node, based on local information.
 504 // If both inputs are constants, compare them.
 505 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 506   const TypeInt *r0 = t1->is_int(); // Handy access
 507   const TypeInt *r1 = t2->is_int();
 508 
 509   if( r0->_hi < r1->_lo )       // Range is always low?
 510     return TypeInt::CC_LT;
 511   else if( r0->_lo > r1->_hi )  // Range is always high?
 512     return TypeInt::CC_GT;
 513 
 514   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 515     assert(r0->get_con() == r1->get_con(), "must be equal");
 516     return TypeInt::CC_EQ;      // Equal results.
 517   } else if( r0->_hi == r1->_lo ) // Range is never high?
 518     return TypeInt::CC_LE;
 519   else if( r0->_lo == r1->_hi ) // Range is never low?
 520     return TypeInt::CC_GE;
 521   return TypeInt::CC;           // else use worst case results
 522 }
 523 
 524 // Simplify a CmpU (compare 2 integers) node, based on local information.
 525 // If both inputs are constants, compare them.
 526 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 527   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 528 
 529   // comparing two unsigned ints
 530   const TypeInt *r0 = t1->is_int();   // Handy access
 531   const TypeInt *r1 = t2->is_int();
 532 
 533   // Current installed version
 534   // Compare ranges for non-overlap
 535   juint lo0 = r0->_lo;
 536   juint hi0 = r0->_hi;
 537   juint lo1 = r1->_lo;
 538   juint hi1 = r1->_hi;
 539 
 540   // If either one has both negative and positive values,
 541   // it therefore contains both 0 and -1, and since [0..-1] is the
 542   // full unsigned range, the type must act as an unsigned bottom.
 543   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 544   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 545 
 546   if (bot0 || bot1) {
 547     // All unsigned values are LE -1 and GE 0.
 548     if (lo0 == 0 && hi0 == 0) {
 549       return TypeInt::CC_LE;            //   0 <= bot
 550     } else if (lo1 == 0 && hi1 == 0) {
 551       return TypeInt::CC_GE;            // bot >= 0
 552     }
 553   } else {
 554     // We can use ranges of the form [lo..hi] if signs are the same.
 555     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 556     // results are reversed, '-' > '+' for unsigned compare
 557     if (hi0 < lo1) {
 558       return TypeInt::CC_LT;            // smaller
 559     } else if (lo0 > hi1) {
 560       return TypeInt::CC_GT;            // greater
 561     } else if (hi0 == lo1 && lo0 == hi1) {
 562       return TypeInt::CC_EQ;            // Equal results
 563     } else if (lo0 >= hi1) {
 564       return TypeInt::CC_GE;
 565     } else if (hi0 <= lo1) {
 566       // Check for special case in Hashtable::get.  (See below.)
 567       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 568         return TypeInt::CC_LT;
 569       return TypeInt::CC_LE;
 570     }
 571   }
 572   // Check for special case in Hashtable::get - the hash index is
 573   // mod'ed to the table size so the following range check is useless.
 574   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 575   // to be positive.
 576   // (This is a gross hack, since the sub method never
 577   // looks at the structure of the node in any other case.)
 578   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 579     return TypeInt::CC_LT;
 580   return TypeInt::CC;                   // else use worst case results
 581 }
 582 
 583 const Type* CmpUNode::Value(PhaseTransform *phase) const {
 584   const Type* t = SubNode::Value_common(phase);
 585   if (t != NULL) {
 586     return t;
 587   }
 588   const Node* in1 = in(1);
 589   const Node* in2 = in(2);
 590   const Type* t1 = phase->type(in1);
 591   const Type* t2 = phase->type(in2);
 592   assert(t1->isa_int(), "CmpU has only Int type inputs");
 593   if (t2 == TypeInt::INT) { // Compare to bottom?
 594     return bottom_type();
 595   }
 596   uint in1_op = in1->Opcode();
 597   if (in1_op == Op_AddI || in1_op == Op_SubI) {
 598     // The problem rise when result of AddI(SubI) may overflow
 599     // signed integer value. Let say the input type is
 600     // [256, maxint] then +128 will create 2 ranges due to
 601     // overflow: [minint, minint+127] and [384, maxint].
 602     // But C2 type system keep only 1 type range and as result
 603     // it use general [minint, maxint] for this case which we
 604     // can't optimize.
 605     //
 606     // Make 2 separate type ranges based on types of AddI(SubI) inputs
 607     // and compare results of their compare. If results are the same
 608     // CmpU node can be optimized.
 609     const Node* in11 = in1->in(1);
 610     const Node* in12 = in1->in(2);
 611     const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11);
 612     const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12);
 613     // Skip cases when input types are top or bottom.
 614     if ((t11 != Type::TOP) && (t11 != TypeInt::INT) &&
 615         (t12 != Type::TOP) && (t12 != TypeInt::INT)) {
 616       const TypeInt *r0 = t11->is_int();
 617       const TypeInt *r1 = t12->is_int();
 618       jlong lo0 = r0->_lo;
 619       jlong hi0 = r0->_hi;
 620       jlong lo1 = r1->_lo;
 621       jlong hi1 = r1->_hi;
 622       if (in1_op == Op_SubI) {
 623         jlong tmp = hi1;
 624         hi1 = -lo1;
 625         lo1 = -tmp;
 626       }
 627       jlong lol = lo0 + lo1;
 628       jlong hil = hi0 + hi1;
 629       bool underflow = lol != (int)lol;
 630       bool overflow  = hil != (int)hil;
 631       // Use sub(t1, t2) when there is no overflow (one type range)
 632       // or when both overflow and underflow (too complex).
 633       if (underflow != overflow) {
 634         // Overflow only on one boundary, compare 2 type ranges.
 635         int lo_r1 = min_jint;
 636         int hi_r1 = (int)hil;
 637         int lo_r2 = (int)lol;
 638         int hi_r2 = max_jint;
 639 
 640         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
 641         const TypeInt* tr1 = TypeInt::make(lo_r1, hi_r1, w);
 642         const TypeInt* tr2 = TypeInt::make(lo_r2, hi_r2, w);
 643         const Type* cmp1 = sub(tr1, t2);
 644         const Type* cmp2 = sub(tr2, t2);
 645         if (cmp1 == cmp2) {
 646           return cmp1; // Hit!
 647         }
 648       }
 649     }
 650   }
 651 
 652   return sub(t1, t2);            // Local flavor of type subtraction
 653 }
 654 
 655 bool CmpUNode::is_index_range_check() const {
 656   // Check for the "(X ModI Y) CmpU Y" shape
 657   return (in(1)->Opcode() == Op_ModI &&
 658           in(1)->in(2)->eqv_uncast(in(2)));
 659 }
 660 
 661 //------------------------------Idealize---------------------------------------
 662 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 663   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 664     switch (in(1)->Opcode()) {
 665     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 666       return new (phase->C) CmpLNode(in(1)->in(1),in(1)->in(2));
 667     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 668       return new (phase->C) CmpFNode(in(1)->in(1),in(1)->in(2));
 669     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 670       return new (phase->C) CmpDNode(in(1)->in(1),in(1)->in(2));
 671     //case Op_SubI:
 672       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 673       // can be turned into (x <?> y).
 674       // This is handled (with more general cases) by Ideal_sub_algebra.
 675     }
 676   }
 677   return NULL;                  // No change
 678 }
 679 
 680 
 681 //=============================================================================
 682 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 683 // If both inputs are constants, compare them.
 684 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 685   const TypeLong *r0 = t1->is_long(); // Handy access
 686   const TypeLong *r1 = t2->is_long();
 687 
 688   if( r0->_hi < r1->_lo )       // Range is always low?
 689     return TypeInt::CC_LT;
 690   else if( r0->_lo > r1->_hi )  // Range is always high?
 691     return TypeInt::CC_GT;
 692 
 693   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 694     assert(r0->get_con() == r1->get_con(), "must be equal");
 695     return TypeInt::CC_EQ;      // Equal results.
 696   } else if( r0->_hi == r1->_lo ) // Range is never high?
 697     return TypeInt::CC_LE;
 698   else if( r0->_lo == r1->_hi ) // Range is never low?
 699     return TypeInt::CC_GE;
 700   return TypeInt::CC;           // else use worst case results
 701 }
 702 
 703 //=============================================================================
 704 //------------------------------sub--------------------------------------------
 705 // Simplify an CmpP (compare 2 pointers) node, based on local information.
 706 // If both inputs are constants, compare them.
 707 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
 708   const TypePtr *r0 = t1->is_ptr(); // Handy access
 709   const TypePtr *r1 = t2->is_ptr();
 710 
 711   // Undefined inputs makes for an undefined result
 712   if( TypePtr::above_centerline(r0->_ptr) ||
 713       TypePtr::above_centerline(r1->_ptr) )
 714     return Type::TOP;
 715 
 716   if (r0 == r1 && r0->singleton()) {
 717     // Equal pointer constants (klasses, nulls, etc.)
 718     return TypeInt::CC_EQ;
 719   }
 720 
 721   // See if it is 2 unrelated classes.
 722   const TypeOopPtr* p0 = r0->isa_oopptr();
 723   const TypeOopPtr* p1 = r1->isa_oopptr();
 724   if (p0 && p1) {
 725     Node* in1 = in(1)->uncast();
 726     Node* in2 = in(2)->uncast();
 727     AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
 728     AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
 729     if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
 730       return TypeInt::CC_GT;  // different pointers
 731     }
 732     ciKlass* klass0 = p0->klass();
 733     bool    xklass0 = p0->klass_is_exact();
 734     ciKlass* klass1 = p1->klass();
 735     bool    xklass1 = p1->klass_is_exact();
 736     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 737     if (klass0 && klass1 &&
 738         kps != 1 &&             // both or neither are klass pointers
 739         klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
 740         klass1->is_loaded() && !klass1->is_interface() &&
 741         (!klass0->is_obj_array_klass() ||
 742          !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
 743         (!klass1->is_obj_array_klass() ||
 744          !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
 745       bool unrelated_classes = false;
 746       // See if neither subclasses the other, or if the class on top
 747       // is precise.  In either of these cases, the compare is known
 748       // to fail if at least one of the pointers is provably not null.
 749       if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
 750         // Do nothing; we know nothing for imprecise types
 751       } else if (klass0->is_subtype_of(klass1)) {
 752         // If klass1's type is PRECISE, then classes are unrelated.
 753         unrelated_classes = xklass1;
 754       } else if (klass1->is_subtype_of(klass0)) {
 755         // If klass0's type is PRECISE, then classes are unrelated.
 756         unrelated_classes = xklass0;
 757       } else {                  // Neither subtypes the other
 758         unrelated_classes = true;
 759       }
 760       if (unrelated_classes) {
 761         // The oops classes are known to be unrelated. If the joined PTRs of
 762         // two oops is not Null and not Bottom, then we are sure that one
 763         // of the two oops is non-null, and the comparison will always fail.
 764         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 765         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 766           return TypeInt::CC_GT;
 767         }
 768       }
 769     }
 770   }
 771 
 772   // Known constants can be compared exactly
 773   // Null can be distinguished from any NotNull pointers
 774   // Unknown inputs makes an unknown result
 775   if( r0->singleton() ) {
 776     intptr_t bits0 = r0->get_con();
 777     if( r1->singleton() )
 778       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
 779     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 780   } else if( r1->singleton() ) {
 781     intptr_t bits1 = r1->get_con();
 782     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
 783   } else
 784     return TypeInt::CC;
 785 }
 786 
 787 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
 788   // Return the klass node for
 789   //   LoadP(AddP(foo:Klass, #java_mirror))
 790   //   or NULL if not matching.
 791   if (n->Opcode() != Op_LoadP) return NULL;
 792 
 793   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 794   if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;
 795 
 796   Node* adr = n->in(MemNode::Address);
 797   intptr_t off = 0;
 798   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
 799   if (k == NULL)  return NULL;
 800   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
 801   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL;
 802 
 803   // We've found the klass node of a Java mirror load.
 804   return k;
 805 }
 806 
 807 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
 808   // for ConP(Foo.class) return ConP(Foo.klass)
 809   // otherwise return NULL
 810   if (!n->is_Con()) return NULL;
 811 
 812   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
 813   if (!tp) return NULL;
 814 
 815   ciType* mirror_type = tp->java_mirror_type();
 816   // TypeInstPtr::java_mirror_type() returns non-NULL for compile-
 817   // time Class constants only.
 818   if (!mirror_type) return NULL;
 819 
 820   // x.getClass() == int.class can never be true (for all primitive types)
 821   // Return a ConP(NULL) node for this case.
 822   if (mirror_type->is_classless()) {
 823     return phase->makecon(TypePtr::NULL_PTR);
 824   }
 825 
 826   // return the ConP(Foo.klass)
 827   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
 828   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass()));
 829 }
 830 
 831 //------------------------------Ideal------------------------------------------
 832 // Normalize comparisons between Java mirror loads to compare the klass instead.
 833 //
 834 // Also check for the case of comparing an unknown klass loaded from the primary
 835 // super-type array vs a known klass with no subtypes.  This amounts to
 836 // checking to see an unknown klass subtypes a known klass with no subtypes;
 837 // this only happens on an exact match.  We can shorten this test by 1 load.
 838 Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 839   // Normalize comparisons between Java mirrors into comparisons of the low-
 840   // level klass, where a dependent load could be shortened.
 841   //
 842   // The new pattern has a nice effect of matching the same pattern used in the
 843   // fast path of instanceof/checkcast/Class.isInstance(), which allows
 844   // redundant exact type check be optimized away by GVN.
 845   // For example, in
 846   //   if (x.getClass() == Foo.class) {
 847   //     Foo foo = (Foo) x;
 848   //     // ... use a ...
 849   //   }
 850   // a CmpPNode could be shared between if_acmpne and checkcast
 851   {
 852     Node* k1 = isa_java_mirror_load(phase, in(1));
 853     Node* k2 = isa_java_mirror_load(phase, in(2));
 854     Node* conk2 = isa_const_java_mirror(phase, in(2));
 855 
 856     if (k1 && (k2 || conk2)) {
 857       Node* lhs = k1;
 858       Node* rhs = (k2 != NULL) ? k2 : conk2;
 859       this->set_req(1, lhs);
 860       this->set_req(2, rhs);
 861       return this;
 862     }
 863   }
 864 
 865   // Constant pointer on right?
 866   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
 867   if (t2 == NULL || !t2->klass_is_exact())
 868     return NULL;
 869   // Get the constant klass we are comparing to.
 870   ciKlass* superklass = t2->klass();
 871 
 872   // Now check for LoadKlass on left.
 873   Node* ldk1 = in(1);
 874   if (ldk1->is_DecodeNKlass()) {
 875     ldk1 = ldk1->in(1);
 876     if (ldk1->Opcode() != Op_LoadNKlass )
 877       return NULL;
 878   } else if (ldk1->Opcode() != Op_LoadKlass )
 879     return NULL;
 880   // Take apart the address of the LoadKlass:
 881   Node* adr1 = ldk1->in(MemNode::Address);
 882   intptr_t con2 = 0;
 883   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
 884   if (ldk2 == NULL)
 885     return NULL;
 886   if (con2 == oopDesc::klass_offset_in_bytes()) {
 887     // We are inspecting an object's concrete class.
 888     // Short-circuit the check if the query is abstract.
 889     if (superklass->is_interface() ||
 890         superklass->is_abstract()) {
 891       // Make it come out always false:
 892       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
 893       return this;
 894     }
 895   }
 896 
 897   // Check for a LoadKlass from primary supertype array.
 898   // Any nested loadklass from loadklass+con must be from the p.s. array.
 899   if (ldk2->is_DecodeNKlass()) {
 900     // Keep ldk2 as DecodeN since it could be used in CmpP below.
 901     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
 902       return NULL;
 903   } else if (ldk2->Opcode() != Op_LoadKlass)
 904     return NULL;
 905 
 906   // Verify that we understand the situation
 907   if (con2 != (intptr_t) superklass->super_check_offset())
 908     return NULL;                // Might be element-klass loading from array klass
 909 
 910   // If 'superklass' has no subklasses and is not an interface, then we are
 911   // assured that the only input which will pass the type check is
 912   // 'superklass' itself.
 913   //
 914   // We could be more liberal here, and allow the optimization on interfaces
 915   // which have a single implementor.  This would require us to increase the
 916   // expressiveness of the add_dependency() mechanism.
 917   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
 918 
 919   // Object arrays must have their base element have no subtypes
 920   while (superklass->is_obj_array_klass()) {
 921     ciType* elem = superklass->as_obj_array_klass()->element_type();
 922     superklass = elem->as_klass();
 923   }
 924   if (superklass->is_instance_klass()) {
 925     ciInstanceKlass* ik = superklass->as_instance_klass();
 926     if (ik->has_subklass() || ik->is_interface())  return NULL;
 927     // Add a dependency if there is a chance that a subclass will be added later.
 928     if (!ik->is_final()) {
 929       phase->C->dependencies()->assert_leaf_type(ik);
 930     }
 931   }
 932 
 933   // Bypass the dependent load, and compare directly
 934   this->set_req(1,ldk2);
 935 
 936   return this;
 937 }
 938 
 939 //=============================================================================
 940 //------------------------------sub--------------------------------------------
 941 // Simplify an CmpN (compare 2 pointers) node, based on local information.
 942 // If both inputs are constants, compare them.
 943 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
 944   const TypePtr *r0 = t1->make_ptr(); // Handy access
 945   const TypePtr *r1 = t2->make_ptr();
 946 
 947   // Undefined inputs makes for an undefined result
 948   if ((r0 == NULL) || (r1 == NULL) ||
 949       TypePtr::above_centerline(r0->_ptr) ||
 950       TypePtr::above_centerline(r1->_ptr)) {
 951     return Type::TOP;
 952   }
 953   if (r0 == r1 && r0->singleton()) {
 954     // Equal pointer constants (klasses, nulls, etc.)
 955     return TypeInt::CC_EQ;
 956   }
 957 
 958   // See if it is 2 unrelated classes.
 959   const TypeOopPtr* p0 = r0->isa_oopptr();
 960   const TypeOopPtr* p1 = r1->isa_oopptr();
 961   if (p0 && p1) {
 962     ciKlass* klass0 = p0->klass();
 963     bool    xklass0 = p0->klass_is_exact();
 964     ciKlass* klass1 = p1->klass();
 965     bool    xklass1 = p1->klass_is_exact();
 966     int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
 967     if (klass0 && klass1 &&
 968         kps != 1 &&             // both or neither are klass pointers
 969         !klass0->is_interface() && // do not trust interfaces
 970         !klass1->is_interface()) {
 971       bool unrelated_classes = false;
 972       // See if neither subclasses the other, or if the class on top
 973       // is precise.  In either of these cases, the compare is known
 974       // to fail if at least one of the pointers is provably not null.
 975       if (klass0->equals(klass1)) { // if types are unequal but klasses are equal
 976         // Do nothing; we know nothing for imprecise types
 977       } else if (klass0->is_subtype_of(klass1)) {
 978         // If klass1's type is PRECISE, then classes are unrelated.
 979         unrelated_classes = xklass1;
 980       } else if (klass1->is_subtype_of(klass0)) {
 981         // If klass0's type is PRECISE, then classes are unrelated.
 982         unrelated_classes = xklass0;
 983       } else {                  // Neither subtypes the other
 984         unrelated_classes = true;
 985       }
 986       if (unrelated_classes) {
 987         // The oops classes are known to be unrelated. If the joined PTRs of
 988         // two oops is not Null and not Bottom, then we are sure that one
 989         // of the two oops is non-null, and the comparison will always fail.
 990         TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
 991         if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
 992           return TypeInt::CC_GT;
 993         }
 994       }
 995     }
 996   }
 997 
 998   // Known constants can be compared exactly
 999   // Null can be distinguished from any NotNull pointers
1000   // Unknown inputs makes an unknown result
1001   if( r0->singleton() ) {
1002     intptr_t bits0 = r0->get_con();
1003     if( r1->singleton() )
1004       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1005     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1006   } else if( r1->singleton() ) {
1007     intptr_t bits1 = r1->get_con();
1008     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1009   } else
1010     return TypeInt::CC;
1011 }
1012 
1013 //------------------------------Ideal------------------------------------------
1014 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1015   return NULL;
1016 }
1017 
1018 //=============================================================================
1019 //------------------------------Value------------------------------------------
1020 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1021 // If both inputs are constants, compare them.
1022 const Type *CmpFNode::Value( PhaseTransform *phase ) const {
1023   const Node* in1 = in(1);
1024   const Node* in2 = in(2);
1025   // Either input is TOP ==> the result is TOP
1026   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1027   if( t1 == Type::TOP ) return Type::TOP;
1028   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1029   if( t2 == Type::TOP ) return Type::TOP;
1030 
1031   // Not constants?  Don't know squat - even if they are the same
1032   // value!  If they are NaN's they compare to LT instead of EQ.
1033   const TypeF *tf1 = t1->isa_float_constant();
1034   const TypeF *tf2 = t2->isa_float_constant();
1035   if( !tf1 || !tf2 ) return TypeInt::CC;
1036 
1037   // This implements the Java bytecode fcmpl, so unordered returns -1.
1038   if( tf1->is_nan() || tf2->is_nan() )
1039     return TypeInt::CC_LT;
1040 
1041   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
1042   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
1043   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
1044   return TypeInt::CC_EQ;
1045 }
1046 
1047 
1048 //=============================================================================
1049 //------------------------------Value------------------------------------------
1050 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
1051 // If both inputs are constants, compare them.
1052 const Type *CmpDNode::Value( PhaseTransform *phase ) const {
1053   const Node* in1 = in(1);
1054   const Node* in2 = in(2);
1055   // Either input is TOP ==> the result is TOP
1056   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1057   if( t1 == Type::TOP ) return Type::TOP;
1058   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1059   if( t2 == Type::TOP ) return Type::TOP;
1060 
1061   // Not constants?  Don't know squat - even if they are the same
1062   // value!  If they are NaN's they compare to LT instead of EQ.
1063   const TypeD *td1 = t1->isa_double_constant();
1064   const TypeD *td2 = t2->isa_double_constant();
1065   if( !td1 || !td2 ) return TypeInt::CC;
1066 
1067   // This implements the Java bytecode dcmpl, so unordered returns -1.
1068   if( td1->is_nan() || td2->is_nan() )
1069     return TypeInt::CC_LT;
1070 
1071   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
1072   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
1073   assert( td1->_d == td2->_d, "do not understand FP behavior" );
1074   return TypeInt::CC_EQ;
1075 }
1076 
1077 //------------------------------Ideal------------------------------------------
1078 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
1079   // Check if we can change this to a CmpF and remove a ConvD2F operation.
1080   // Change  (CMPD (F2D (float)) (ConD value))
1081   // To      (CMPF      (float)  (ConF value))
1082   // Valid when 'value' does not lose precision as a float.
1083   // Benefits: eliminates conversion, does not require 24-bit mode
1084 
1085   // NaNs prevent commuting operands.  This transform works regardless of the
1086   // order of ConD and ConvF2D inputs by preserving the original order.
1087   int idx_f2d = 1;              // ConvF2D on left side?
1088   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1089     idx_f2d = 2;                // No, swap to check for reversed args
1090   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1091 
1092   if( ConvertCmpD2CmpF &&
1093       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1094       in(idx_con)->Opcode() == Op_ConD ) {
1095     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1096     double t2_value_as_double = t2->_d;
1097     float  t2_value_as_float  = (float)t2_value_as_double;
1098     if( t2_value_as_double == (double)t2_value_as_float ) {
1099       // Test value can be represented as a float
1100       // Eliminate the conversion to double and create new comparison
1101       Node *new_in1 = in(idx_f2d)->in(1);
1102       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1103       if( idx_f2d != 1 ) {      // Must flip args to match original order
1104         Node *tmp = new_in1;
1105         new_in1 = new_in2;
1106         new_in2 = tmp;
1107       }
1108       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1109         ? new (phase->C) CmpF3Node( new_in1, new_in2 )
1110         : new (phase->C) CmpFNode ( new_in1, new_in2 ) ;
1111       return new_cmp;           // Changed to CmpFNode
1112     }
1113     // Testing value required the precision of a double
1114   }
1115   return NULL;                  // No change
1116 }
1117 
1118 
1119 //=============================================================================
1120 //------------------------------cc2logical-------------------------------------
1121 // Convert a condition code type to a logical type
1122 const Type *BoolTest::cc2logical( const Type *CC ) const {
1123   if( CC == Type::TOP ) return Type::TOP;
1124   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1125   const TypeInt *ti = CC->is_int();
1126   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1127     // Match low order 2 bits
1128     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1129     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1130     return TypeInt::make(tmp);       // Boolean result
1131   }
1132 
1133   if( CC == TypeInt::CC_GE ) {
1134     if( _test == ge ) return TypeInt::ONE;
1135     if( _test == lt ) return TypeInt::ZERO;
1136   }
1137   if( CC == TypeInt::CC_LE ) {
1138     if( _test == le ) return TypeInt::ONE;
1139     if( _test == gt ) return TypeInt::ZERO;
1140   }
1141 
1142   return TypeInt::BOOL;
1143 }
1144 
1145 //------------------------------dump_spec-------------------------------------
1146 // Print special per-node info
1147 #ifndef PRODUCT
1148 void BoolTest::dump_on(outputStream *st) const {
1149   const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
1150   st->print("%s", msg[_test]);
1151 }
1152 #endif
1153 
1154 //=============================================================================
1155 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1156 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1157 
1158 //------------------------------operator==-------------------------------------
1159 uint BoolNode::cmp( const Node &n ) const {
1160   const BoolNode *b = (const BoolNode *)&n; // Cast up
1161   return (_test._test == b->_test._test);
1162 }
1163 
1164 //-------------------------------make_predicate--------------------------------
1165 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1166   if (test_value->is_Con())   return test_value;
1167   if (test_value->is_Bool())  return test_value;
1168   Compile* C = phase->C;
1169   if (test_value->is_CMove() &&
1170       test_value->in(CMoveNode::Condition)->is_Bool()) {
1171     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1172     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1173     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1174     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1175       return bol;
1176     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1177       return phase->transform( bol->negate(phase) );
1178     }
1179     // Else fall through.  The CMove gets in the way of the test.
1180     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1181   }
1182   Node* cmp = new (C) CmpINode(test_value, phase->intcon(0));
1183   cmp = phase->transform(cmp);
1184   Node* bol = new (C) BoolNode(cmp, BoolTest::ne);
1185   return phase->transform(bol);
1186 }
1187 
1188 //--------------------------------as_int_value---------------------------------
1189 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1190   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1191   Node* cmov = CMoveNode::make(phase->C, NULL, this,
1192                                phase->intcon(0), phase->intcon(1),
1193                                TypeInt::BOOL);
1194   return phase->transform(cmov);
1195 }
1196 
1197 //----------------------------------negate-------------------------------------
1198 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1199   Compile* C = phase->C;
1200   return new (C) BoolNode(in(1), _test.negate());
1201 }
1202 
1203 
1204 //------------------------------Ideal------------------------------------------
1205 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1206   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1207   // This moves the constant to the right.  Helps value-numbering.
1208   Node *cmp = in(1);
1209   if( !cmp->is_Sub() ) return NULL;
1210   int cop = cmp->Opcode();
1211   if( cop == Op_FastLock || cop == Op_FastUnlock) return NULL;
1212   Node *cmp1 = cmp->in(1);
1213   Node *cmp2 = cmp->in(2);
1214   if( !cmp1 ) return NULL;
1215 
1216   if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) {
1217     return NULL;
1218   }
1219 
1220   // Constant on left?
1221   Node *con = cmp1;
1222   uint op2 = cmp2->Opcode();
1223   // Move constants to the right of compare's to canonicalize.
1224   // Do not muck with Opaque1 nodes, as this indicates a loop
1225   // guard that cannot change shape.
1226   if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 &&
1227       // Because of NaN's, CmpD and CmpF are not commutative
1228       cop != Op_CmpD && cop != Op_CmpF &&
1229       // Protect against swapping inputs to a compare when it is used by a
1230       // counted loop exit, which requires maintaining the loop-limit as in(2)
1231       !is_counted_loop_exit_test() ) {
1232     // Ok, commute the constant to the right of the cmp node.
1233     // Clone the Node, getting a new Node of the same class
1234     cmp = cmp->clone();
1235     // Swap inputs to the clone
1236     cmp->swap_edges(1, 2);
1237     cmp = phase->transform( cmp );
1238     return new (phase->C) BoolNode( cmp, _test.commute() );
1239   }
1240 
1241   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1242   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1243   // test instead.
1244   int cmp1_op = cmp1->Opcode();
1245   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1246   if (cmp2_type == NULL)  return NULL;
1247   Node* j_xor = cmp1;
1248   if( cmp2_type == TypeInt::ZERO &&
1249       cmp1_op == Op_XorI &&
1250       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1251       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1252       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1253       (_test._test == BoolTest::eq ||
1254        _test._test == BoolTest::ne) ) {
1255     Node *ncmp = phase->transform(new (phase->C) CmpINode(j_xor->in(1),cmp2));
1256     return new (phase->C) BoolNode( ncmp, _test.negate() );
1257   }
1258 
1259   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1260   // This is a standard idiom for branching on a boolean value.
1261   Node *c2b = cmp1;
1262   if( cmp2_type == TypeInt::ZERO &&
1263       cmp1_op == Op_Conv2B &&
1264       (_test._test == BoolTest::eq ||
1265        _test._test == BoolTest::ne) ) {
1266     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1267        ? (Node*)new (phase->C) CmpINode(c2b->in(1),cmp2)
1268        : (Node*)new (phase->C) CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1269     );
1270     return new (phase->C) BoolNode( ncmp, _test._test );
1271   }
1272 
1273   // Comparing a SubI against a zero is equal to comparing the SubI
1274   // arguments directly.  This only works for eq and ne comparisons
1275   // due to possible integer overflow.
1276   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1277         (cop == Op_CmpI) &&
1278         (cmp1->Opcode() == Op_SubI) &&
1279         ( cmp2_type == TypeInt::ZERO ) ) {
1280     Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(1),cmp1->in(2)));
1281     return new (phase->C) BoolNode( ncmp, _test._test );
1282   }
1283 
1284   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1285   // most general case because negating 0x80000000 does nothing.  Needed for
1286   // the CmpF3/SubI/CmpI idiom.
1287   if( cop == Op_CmpI &&
1288       cmp1->Opcode() == Op_SubI &&
1289       cmp2_type == TypeInt::ZERO &&
1290       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1291       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1292     Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(2),cmp2));
1293     return new (phase->C) BoolNode( ncmp, _test.commute() );
1294   }
1295 
1296   //  The transformation below is not valid for either signed or unsigned
1297   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1298   //  This transformation can be resurrected when we are able to
1299   //  make inferences about the range of values being subtracted from
1300   //  (or added to) relative to the wraparound point.
1301   //
1302   //    // Remove +/-1's if possible.
1303   //    // "X <= Y-1" becomes "X <  Y"
1304   //    // "X+1 <= Y" becomes "X <  Y"
1305   //    // "X <  Y+1" becomes "X <= Y"
1306   //    // "X-1 <  Y" becomes "X <= Y"
1307   //    // Do not this to compares off of the counted-loop-end.  These guys are
1308   //    // checking the trip counter and they want to use the post-incremented
1309   //    // counter.  If they use the PRE-incremented counter, then the counter has
1310   //    // to be incremented in a private block on a loop backedge.
1311   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1312   //      return NULL;
1313   //  #ifndef PRODUCT
1314   //    // Do not do this in a wash GVN pass during verification.
1315   //    // Gets triggered by too many simple optimizations to be bothered with
1316   //    // re-trying it again and again.
1317   //    if( !phase->allow_progress() ) return NULL;
1318   //  #endif
1319   //    // Not valid for unsigned compare because of corner cases in involving zero.
1320   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1321   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1322   //    // "0 <=u Y" is always true).
1323   //    if( cmp->Opcode() == Op_CmpU ) return NULL;
1324   //    int cmp2_op = cmp2->Opcode();
1325   //    if( _test._test == BoolTest::le ) {
1326   //      if( cmp1_op == Op_AddI &&
1327   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1328   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1329   //      else if( cmp2_op == Op_AddI &&
1330   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1331   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1332   //    } else if( _test._test == BoolTest::lt ) {
1333   //      if( cmp1_op == Op_AddI &&
1334   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1335   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1336   //      else if( cmp2_op == Op_AddI &&
1337   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1338   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1339   //    }
1340 
1341   return NULL;
1342 }
1343 
1344 //------------------------------Value------------------------------------------
1345 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
1346 // based on local information.   If the input is constant, do it.
1347 const Type *BoolNode::Value( PhaseTransform *phase ) const {
1348   return _test.cc2logical( phase->type( in(1) ) );
1349 }
1350 
1351 //------------------------------dump_spec--------------------------------------
1352 // Dump special per-node info
1353 #ifndef PRODUCT
1354 void BoolNode::dump_spec(outputStream *st) const {
1355   st->print("[");
1356   _test.dump_on(st);
1357   st->print("]");
1358 }
1359 #endif
1360 
1361 //------------------------------is_counted_loop_exit_test--------------------------------------
1362 // Returns true if node is used by a counted loop node.
1363 bool BoolNode::is_counted_loop_exit_test() {
1364   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
1365     Node* use = fast_out(i);
1366     if (use->is_CountedLoopEnd()) {
1367       return true;
1368     }
1369   }
1370   return false;
1371 }
1372 
1373 //=============================================================================
1374 //------------------------------Value------------------------------------------
1375 // Compute sqrt
1376 const Type *SqrtDNode::Value( PhaseTransform *phase ) const {
1377   const Type *t1 = phase->type( in(1) );
1378   if( t1 == Type::TOP ) return Type::TOP;
1379   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1380   double d = t1->getd();
1381   if( d < 0.0 ) return Type::DOUBLE;
1382   return TypeD::make( sqrt( d ) );
1383 }
1384 
1385 //=============================================================================
1386 //------------------------------Value------------------------------------------
1387 // Compute cos
1388 const Type *CosDNode::Value( PhaseTransform *phase ) const {
1389   const Type *t1 = phase->type( in(1) );
1390   if( t1 == Type::TOP ) return Type::TOP;
1391   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1392   double d = t1->getd();
1393   return TypeD::make( StubRoutines::intrinsic_cos( d ) );
1394 }
1395 
1396 //=============================================================================
1397 //------------------------------Value------------------------------------------
1398 // Compute sin
1399 const Type *SinDNode::Value( PhaseTransform *phase ) const {
1400   const Type *t1 = phase->type( in(1) );
1401   if( t1 == Type::TOP ) return Type::TOP;
1402   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1403   double d = t1->getd();
1404   return TypeD::make( StubRoutines::intrinsic_sin( d ) );
1405 }
1406 
1407 //=============================================================================
1408 //------------------------------Value------------------------------------------
1409 // Compute tan
1410 const Type *TanDNode::Value( PhaseTransform *phase ) const {
1411   const Type *t1 = phase->type( in(1) );
1412   if( t1 == Type::TOP ) return Type::TOP;
1413   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1414   double d = t1->getd();
1415   return TypeD::make( StubRoutines::intrinsic_tan( d ) );
1416 }
1417 
1418 //=============================================================================
1419 //------------------------------Value------------------------------------------
1420 // Compute log
1421 const Type *LogDNode::Value( PhaseTransform *phase ) const {
1422   const Type *t1 = phase->type( in(1) );
1423   if( t1 == Type::TOP ) return Type::TOP;
1424   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1425   double d = t1->getd();
1426   return TypeD::make( StubRoutines::intrinsic_log( d ) );
1427 }
1428 
1429 //=============================================================================
1430 //------------------------------Value------------------------------------------
1431 // Compute log10
1432 const Type *Log10DNode::Value( PhaseTransform *phase ) const {
1433   const Type *t1 = phase->type( in(1) );
1434   if( t1 == Type::TOP ) return Type::TOP;
1435   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1436   double d = t1->getd();
1437   return TypeD::make( StubRoutines::intrinsic_log10( d ) );
1438 }
1439 
1440 //=============================================================================
1441 //------------------------------Value------------------------------------------
1442 // Compute exp
1443 const Type *ExpDNode::Value( PhaseTransform *phase ) const {
1444   const Type *t1 = phase->type( in(1) );
1445   if( t1 == Type::TOP ) return Type::TOP;
1446   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1447   double d = t1->getd();
1448   return TypeD::make( StubRoutines::intrinsic_exp( d ) );
1449 }
1450 
1451 
1452 //=============================================================================
1453 //------------------------------Value------------------------------------------
1454 // Compute pow
1455 const Type *PowDNode::Value( PhaseTransform *phase ) const {
1456   const Type *t1 = phase->type( in(1) );
1457   if( t1 == Type::TOP ) return Type::TOP;
1458   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
1459   const Type *t2 = phase->type( in(2) );
1460   if( t2 == Type::TOP ) return Type::TOP;
1461   if( t2->base() != Type::DoubleCon ) return Type::DOUBLE;
1462   double d1 = t1->getd();
1463   double d2 = t2->getd();
1464   return TypeD::make( StubRoutines::intrinsic_pow( d1, d2 ) );
1465 }