1 /*
   2  * Copyright (c) 1997, 2025, 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
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  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.
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  23  */
  24 
  25 #include "compiler/compileLog.hpp"
  26 #include "gc/shared/barrierSet.hpp"
  27 #include "gc/shared/c2/barrierSetC2.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "opto/addnode.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/inlinetypenode.hpp"
  33 #include "opto/loopnode.hpp"
  34 #include "opto/matcher.hpp"
  35 #include "opto/movenode.hpp"
  36 #include "opto/mulnode.hpp"
  37 #include "opto/opaquenode.hpp"
  38 #include "opto/opcodes.hpp"
  39 #include "opto/phaseX.hpp"
  40 #include "opto/subnode.hpp"
  41 #include "runtime/sharedRuntime.hpp"
  42 #include "utilities/reverse_bits.hpp"
  43 
  44 // Portions of code courtesy of Clifford Click
  45 
  46 // Optimization - Graph Style
  47 
  48 #include "math.h"
  49 
  50 //=============================================================================
  51 //------------------------------Identity---------------------------------------
  52 // If right input is a constant 0, return the left input.
  53 Node* SubNode::Identity(PhaseGVN* phase) {
  54   assert(in(1) != this, "Must already have called Value");
  55   assert(in(2) != this, "Must already have called Value");
  56 
  57   const Type* zero = add_id();
  58 
  59   // Remove double negation if it is not a floating point number since negation
  60   // is not the same as subtraction for floating point numbers
  61   // (cf. JLS § 15.15.4). `0-(0-(-0.0))` must be equal to positive 0.0 according to
  62   // JLS § 15.8.2, but would result in -0.0 if this folding would be applied.
  63   if (phase->type(in(1))->higher_equal(zero) &&
  64       in(2)->Opcode() == Opcode() &&
  65       phase->type(in(2)->in(1))->higher_equal(zero) &&
  66       !phase->type(in(2)->in(2))->is_floatingpoint()) {
  67     return in(2)->in(2);
  68   }
  69 
  70   // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y
  71   if (in(1)->Opcode() == Op_AddI || in(1)->Opcode() == Op_AddL) {
  72     if (in(1)->in(2) == in(2)) {
  73       return in(1)->in(1);
  74     }
  75     if (in(1)->in(1) == in(2)) {
  76       return in(1)->in(2);
  77     }
  78   }
  79 
  80   return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this;
  81 }
  82 
  83 //------------------------------Value------------------------------------------
  84 // A subtract node differences it's two inputs.
  85 const Type* SubNode::Value_common(PhaseValues* phase) const {
  86   const Node* in1 = in(1);
  87   const Node* in2 = in(2);
  88   // Either input is TOP ==> the result is TOP
  89   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  90   if( t1 == Type::TOP ) return Type::TOP;
  91   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  92   if( t2 == Type::TOP ) return Type::TOP;
  93 
  94   // Not correct for SubFnode and AddFNode (must check for infinity)
  95   // Equal?  Subtract is zero
  96   if (in1->eqv_uncast(in2))  return add_id();
  97 
  98   // Either input is BOTTOM ==> the result is the local BOTTOM
  99   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
 100     return bottom_type();
 101 
 102   return nullptr;
 103 }
 104 
 105 const Type* SubNode::Value(PhaseGVN* phase) const {
 106   const Type* t = Value_common(phase);
 107   if (t != nullptr) {
 108     return t;
 109   }
 110   const Type* t1 = phase->type(in(1));
 111   const Type* t2 = phase->type(in(2));
 112   return sub(t1,t2);            // Local flavor of type subtraction
 113 
 114 }
 115 
 116 SubNode* SubNode::make(Node* in1, Node* in2, BasicType bt) {
 117   switch (bt) {
 118     case T_INT:
 119       return new SubINode(in1, in2);
 120     case T_LONG:
 121       return new SubLNode(in1, in2);
 122     default:
 123       fatal("Not implemented for %s", type2name(bt));
 124   }
 125   return nullptr;
 126 }
 127 
 128 //=============================================================================
 129 //------------------------------Helper function--------------------------------
 130 
 131 static bool is_cloop_increment(Node* inc) {
 132   precond(inc->Opcode() == Op_AddI || inc->Opcode() == Op_AddL);
 133 
 134   if (!inc->in(1)->is_Phi()) {
 135     return false;
 136   }
 137   const PhiNode* phi = inc->in(1)->as_Phi();
 138 
 139   if (!phi->region()->is_CountedLoop()) {
 140     return false;
 141   }
 142 
 143   return inc == phi->region()->as_CountedLoop()->incr();
 144 }
 145 
 146 // Given the expression '(x + C) - v', or
 147 //                      'v - (x + C)', we examine nodes '+' and 'v':
 148 //
 149 //  1. Do not convert if '+' is a counted-loop increment, because the '-' is
 150 //     loop invariant and converting extends the live-range of 'x' to overlap
 151 //     with the '+', forcing another register to be used in the loop.
 152 //
 153 //  2. Do not convert if 'v' is a counted-loop induction variable, because
 154 //     'x' might be invariant.
 155 //
 156 static bool ok_to_convert(Node* inc, Node* var) {
 157   return !(is_cloop_increment(inc) || var->is_cloop_ind_var());
 158 }
 159 
 160 static bool is_cloop_condition(BoolNode* bol) {
 161   for (DUIterator_Fast imax, i = bol->fast_outs(imax); i < imax; i++) {
 162     Node* out = bol->fast_out(i);
 163     if (out->is_BaseCountedLoopEnd()) {
 164       return true;
 165     }
 166   }
 167   return false;
 168 }
 169 
 170 //------------------------------Ideal------------------------------------------
 171 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
 172   Node *in1 = in(1);
 173   Node *in2 = in(2);
 174   uint op1 = in1->Opcode();
 175   uint op2 = in2->Opcode();
 176 
 177 #ifdef ASSERT
 178   // Check for dead loop
 179   if ((in1 == this) || (in2 == this) ||
 180       ((op1 == Op_AddI || op1 == Op_SubI) &&
 181        ((in1->in(1) == this) || (in1->in(2) == this) ||
 182         (in1->in(1) == in1)  || (in1->in(2) == in1)))) {
 183     assert(false, "dead loop in SubINode::Ideal");
 184   }
 185 #endif
 186 
 187   const Type *t2 = phase->type( in2 );
 188   if( t2 == Type::TOP ) return nullptr;
 189   // Convert "x-c0" into "x+ -c0".
 190   if( t2->base() == Type::Int ){        // Might be bottom or top...
 191     const TypeInt *i = t2->is_int();
 192     if( i->is_con() )
 193       return new AddINode(in1, phase->intcon(java_negate(i->get_con())));
 194   }
 195 
 196   // Convert "(x+c0) - y" into (x-y) + c0"
 197   // Do not collapse (x+c0)-y if "+" is a loop increment or
 198   // if "y" is a loop induction variable.
 199   if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
 200     const Type *tadd = phase->type( in1->in(2) );
 201     if( tadd->singleton() && tadd != Type::TOP ) {
 202       Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 ));
 203       return new AddINode( sub2, in1->in(2) );
 204     }
 205   }
 206 
 207   // Convert "x - (y+c0)" into "(x-y) - c0" AND
 208   // Convert "c1 - (y+c0)" into "(c1-c0) - y"
 209   // Need the same check as in above optimization but reversed.
 210   if (op2 == Op_AddI
 211       && ok_to_convert(in2, in1)
 212       && in2->in(2)->Opcode() == Op_ConI) {
 213     jint c0 = phase->type(in2->in(2))->isa_int()->get_con();
 214     Node* in21 = in2->in(1);
 215     if (in1->Opcode() == Op_ConI) {
 216       // Match c1
 217       jint c1 = phase->type(in1)->isa_int()->get_con();
 218       Node* sub2 = phase->intcon(java_subtract(c1, c0));
 219       return new SubINode(sub2, in21);
 220     } else {
 221       // Match x
 222       Node* sub2 = phase->transform(new SubINode(in1, in21));
 223       Node* neg_c0 = phase->intcon(java_negate(c0));
 224       return new AddINode(sub2, neg_c0);
 225     }
 226   }
 227 
 228   const Type *t1 = phase->type( in1 );
 229   if( t1 == Type::TOP ) return nullptr;
 230 
 231 #ifdef ASSERT
 232   // Check for dead loop
 233   if ((op2 == Op_AddI || op2 == Op_SubI) &&
 234       ((in2->in(1) == this) || (in2->in(2) == this) ||
 235        (in2->in(1) == in2)  || (in2->in(2) == in2))) {
 236     assert(false, "dead loop in SubINode::Ideal");
 237   }
 238 #endif
 239 
 240   // Convert "x - (x+y)" into "-y"
 241   if (op2 == Op_AddI && in1 == in2->in(1)) {
 242     return new SubINode(phase->intcon(0), in2->in(2));
 243   }
 244   // Convert "(x-y) - x" into "-y"
 245   if (op1 == Op_SubI && in1->in(1) == in2) {
 246     return new SubINode(phase->intcon(0), in1->in(2));
 247   }
 248   // Convert "x - (y+x)" into "-y"
 249   if (op2 == Op_AddI && in1 == in2->in(2)) {
 250     return new SubINode(phase->intcon(0), in2->in(1));
 251   }
 252 
 253   // Convert "0 - (x-y)" into "y-x", leave the double negation "-(-y)" to SubNode::Identity().
 254   if (t1 == TypeInt::ZERO && op2 == Op_SubI && phase->type(in2->in(1)) != TypeInt::ZERO) {
 255     return new SubINode(in2->in(2), in2->in(1));
 256   }
 257 
 258   // Convert "0 - (x+con)" into "-con-x"
 259   jint con;
 260   if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
 261       (con = in2->in(2)->find_int_con(0)) != 0 )
 262     return new SubINode( phase->intcon(-con), in2->in(1) );
 263 
 264   // Convert "(X+A) - (X+B)" into "A - B"
 265   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
 266     return new SubINode( in1->in(2), in2->in(2) );
 267 
 268   // Convert "(A+X) - (B+X)" into "A - B"
 269   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
 270     return new SubINode( in1->in(1), in2->in(1) );
 271 
 272   // Convert "(A+X) - (X+B)" into "A - B"
 273   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
 274     return new SubINode( in1->in(1), in2->in(2) );
 275 
 276   // Convert "(X+A) - (B+X)" into "A - B"
 277   if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
 278     return new SubINode( in1->in(2), in2->in(1) );
 279 
 280   // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
 281   // nicer to optimize than subtract.
 282   if( op2 == Op_SubI && in2->outcnt() == 1) {
 283     Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) );
 284     return new SubINode( add1, in2->in(1) );
 285   }
 286 
 287   // Associative
 288   if (op1 == Op_MulI && op2 == Op_MulI) {
 289     Node* sub_in1 = nullptr;
 290     Node* sub_in2 = nullptr;
 291     Node* mul_in = nullptr;
 292 
 293     if (in1->in(1) == in2->in(1)) {
 294       // Convert "a*b-a*c into a*(b-c)
 295       sub_in1 = in1->in(2);
 296       sub_in2 = in2->in(2);
 297       mul_in = in1->in(1);
 298     } else if (in1->in(2) == in2->in(1)) {
 299       // Convert a*b-b*c into b*(a-c)
 300       sub_in1 = in1->in(1);
 301       sub_in2 = in2->in(2);
 302       mul_in = in1->in(2);
 303     } else if (in1->in(2) == in2->in(2)) {
 304       // Convert a*c-b*c into (a-b)*c
 305       sub_in1 = in1->in(1);
 306       sub_in2 = in2->in(1);
 307       mul_in = in1->in(2);
 308     } else if (in1->in(1) == in2->in(2)) {
 309       // Convert a*b-c*a into a*(b-c)
 310       sub_in1 = in1->in(2);
 311       sub_in2 = in2->in(1);
 312       mul_in = in1->in(1);
 313     }
 314 
 315     if (mul_in != nullptr) {
 316       Node* sub = phase->transform(new SubINode(sub_in1, sub_in2));
 317       return new MulINode(mul_in, sub);
 318     }
 319   }
 320 
 321   // Convert "0-(A>>31)" into "(A>>>31)"
 322   if ( op2 == Op_RShiftI ) {
 323     Node *in21 = in2->in(1);
 324     Node *in22 = in2->in(2);
 325     const TypeInt *zero = phase->type(in1)->isa_int();
 326     const TypeInt *t21 = phase->type(in21)->isa_int();
 327     const TypeInt *t22 = phase->type(in22)->isa_int();
 328     if ( t21 && t22 && zero == TypeInt::ZERO && t22->is_con(31) ) {
 329       return new URShiftINode(in21, in22);
 330     }
 331   }
 332 
 333   return nullptr;
 334 }
 335 
 336 //------------------------------sub--------------------------------------------
 337 // A subtract node differences it's two inputs.
 338 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
 339   const TypeInt *r0 = t1->is_int(); // Handy access
 340   const TypeInt *r1 = t2->is_int();
 341   int32_t lo = java_subtract(r0->_lo, r1->_hi);
 342   int32_t hi = java_subtract(r0->_hi, r1->_lo);
 343 
 344   // We next check for 32-bit overflow.
 345   // If that happens, we just assume all integers are possible.
 346   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 347        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 348       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 349        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 350     return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 351   else                          // Overflow; assume all integers
 352     return TypeInt::INT;
 353 }
 354 
 355 //=============================================================================
 356 //------------------------------Ideal------------------------------------------
 357 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 358   Node *in1 = in(1);
 359   Node *in2 = in(2);
 360   uint op1 = in1->Opcode();
 361   uint op2 = in2->Opcode();
 362 
 363 #ifdef ASSERT
 364   // Check for dead loop
 365   if ((in1 == this) || (in2 == this) ||
 366       ((op1 == Op_AddL || op1 == Op_SubL) &&
 367        ((in1->in(1) == this) || (in1->in(2) == this) ||
 368         (in1->in(1) == in1)  || (in1->in(2) == in1)))) {
 369     assert(false, "dead loop in SubLNode::Ideal");
 370   }
 371 #endif
 372 
 373   if( phase->type( in2 ) == Type::TOP ) return nullptr;
 374   const TypeLong *i = phase->type( in2 )->isa_long();
 375   // Convert "x-c0" into "x+ -c0".
 376   if( i &&                      // Might be bottom or top...
 377       i->is_con() )
 378     return new AddLNode(in1, phase->longcon(java_negate(i->get_con())));
 379 
 380   // Convert "(x+c0) - y" into (x-y) + c0"
 381   // Do not collapse (x+c0)-y if "+" is a loop increment or
 382   // if "y" is a loop induction variable.
 383   if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
 384     Node *in11 = in1->in(1);
 385     const Type *tadd = phase->type( in1->in(2) );
 386     if( tadd->singleton() && tadd != Type::TOP ) {
 387       Node *sub2 = phase->transform( new SubLNode( in11, in2 ));
 388       return new AddLNode( sub2, in1->in(2) );
 389     }
 390   }
 391 
 392   // Convert "x - (y+c0)" into "(x-y) - c0" AND
 393   // Convert "c1 - (y+c0)" into "(c1-c0) - y"
 394   // Need the same check as in above optimization but reversed.
 395   if (op2 == Op_AddL
 396       && ok_to_convert(in2, in1)
 397       && in2->in(2)->Opcode() == Op_ConL) {
 398     jlong c0 = phase->type(in2->in(2))->isa_long()->get_con();
 399     Node* in21 = in2->in(1);
 400     if (in1->Opcode() == Op_ConL) {
 401       // Match c1
 402       jlong c1 = phase->type(in1)->isa_long()->get_con();
 403       Node* sub2 = phase->longcon(java_subtract(c1, c0));
 404       return new SubLNode(sub2, in21);
 405     } else {
 406       Node* sub2 = phase->transform(new SubLNode(in1, in21));
 407       Node* neg_c0 = phase->longcon(java_negate(c0));
 408       return new AddLNode(sub2, neg_c0);
 409     }
 410   }
 411 
 412   const Type *t1 = phase->type( in1 );
 413   if( t1 == Type::TOP ) return nullptr;
 414 
 415 #ifdef ASSERT
 416   // Check for dead loop
 417   if ((op2 == Op_AddL || op2 == Op_SubL) &&
 418       ((in2->in(1) == this) || (in2->in(2) == this) ||
 419        (in2->in(1) == in2)  || (in2->in(2) == in2))) {
 420     assert(false, "dead loop in SubLNode::Ideal");
 421   }
 422 #endif
 423 
 424   // Convert "x - (x+y)" into "-y"
 425   if (op2 == Op_AddL && in1 == in2->in(1)) {
 426     return new SubLNode(phase->makecon(TypeLong::ZERO), in2->in(2));
 427   }
 428   // Convert "(x-y) - x" into "-y"
 429   if (op1 == Op_SubL && in1->in(1) == in2) {
 430     return new SubLNode(phase->makecon(TypeLong::ZERO), in1->in(2));
 431   }
 432   // Convert "x - (y+x)" into "-y"
 433   if (op2 == Op_AddL && in1 == in2->in(2)) {
 434     return new SubLNode(phase->makecon(TypeLong::ZERO), in2->in(1));
 435   }
 436 
 437   // Convert "0 - (x-y)" into "y-x", leave the double negation "-(-y)" to SubNode::Identity.
 438   if (t1 == TypeLong::ZERO && op2 == Op_SubL && phase->type(in2->in(1)) != TypeLong::ZERO) {
 439     return new SubLNode(in2->in(2), in2->in(1));
 440   }
 441 
 442   // Convert "(X+A) - (X+B)" into "A - B"
 443   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
 444     return new SubLNode( in1->in(2), in2->in(2) );
 445 
 446   // Convert "(A+X) - (B+X)" into "A - B"
 447   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
 448     return new SubLNode( in1->in(1), in2->in(1) );
 449 
 450   // Convert "(A+X) - (X+B)" into "A - B"
 451   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(1) )
 452     return new SubLNode( in1->in(1), in2->in(2) );
 453 
 454   // Convert "(X+A) - (B+X)" into "A - B"
 455   if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(2) )
 456     return new SubLNode( in1->in(2), in2->in(1) );
 457 
 458   // Convert "A-(B-C)" into (A+C)-B"
 459   if( op2 == Op_SubL && in2->outcnt() == 1) {
 460     Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) );
 461     return new SubLNode( add1, in2->in(1) );
 462   }
 463 
 464   // Associative
 465   if (op1 == Op_MulL && op2 == Op_MulL) {
 466     Node* sub_in1 = nullptr;
 467     Node* sub_in2 = nullptr;
 468     Node* mul_in = nullptr;
 469 
 470     if (in1->in(1) == in2->in(1)) {
 471       // Convert "a*b-a*c into a*(b+c)
 472       sub_in1 = in1->in(2);
 473       sub_in2 = in2->in(2);
 474       mul_in = in1->in(1);
 475     } else if (in1->in(2) == in2->in(1)) {
 476       // Convert a*b-b*c into b*(a-c)
 477       sub_in1 = in1->in(1);
 478       sub_in2 = in2->in(2);
 479       mul_in = in1->in(2);
 480     } else if (in1->in(2) == in2->in(2)) {
 481       // Convert a*c-b*c into (a-b)*c
 482       sub_in1 = in1->in(1);
 483       sub_in2 = in2->in(1);
 484       mul_in = in1->in(2);
 485     } else if (in1->in(1) == in2->in(2)) {
 486       // Convert a*b-c*a into a*(b-c)
 487       sub_in1 = in1->in(2);
 488       sub_in2 = in2->in(1);
 489       mul_in = in1->in(1);
 490     }
 491 
 492     if (mul_in != nullptr) {
 493       Node* sub = phase->transform(new SubLNode(sub_in1, sub_in2));
 494       return new MulLNode(mul_in, sub);
 495     }
 496   }
 497 
 498   // Convert "0L-(A>>63)" into "(A>>>63)"
 499   if ( op2 == Op_RShiftL ) {
 500     Node *in21 = in2->in(1);
 501     Node *in22 = in2->in(2);
 502     const TypeLong *zero = phase->type(in1)->isa_long();
 503     const TypeLong *t21 = phase->type(in21)->isa_long();
 504     const TypeInt *t22 = phase->type(in22)->isa_int();
 505     if ( t21 && t22 && zero == TypeLong::ZERO && t22->is_con(63) ) {
 506       return new URShiftLNode(in21, in22);
 507     }
 508   }
 509 
 510   return nullptr;
 511 }
 512 
 513 //------------------------------sub--------------------------------------------
 514 // A subtract node differences it's two inputs.
 515 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
 516   const TypeLong *r0 = t1->is_long(); // Handy access
 517   const TypeLong *r1 = t2->is_long();
 518   jlong lo = java_subtract(r0->_lo, r1->_hi);
 519   jlong hi = java_subtract(r0->_hi, r1->_lo);
 520 
 521   // We next check for 32-bit overflow.
 522   // If that happens, we just assume all integers are possible.
 523   if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
 524        ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
 525       (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
 526        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 527     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 528   else                          // Overflow; assume all integers
 529     return TypeLong::LONG;
 530 }
 531 
 532 //=============================================================================
 533 //------------------------------Value------------------------------------------
 534 // A subtract node differences its two inputs.
 535 const Type* SubFPNode::Value(PhaseGVN* phase) const {
 536   const Node* in1 = in(1);
 537   const Node* in2 = in(2);
 538   // Either input is TOP ==> the result is TOP
 539   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
 540   if( t1 == Type::TOP ) return Type::TOP;
 541   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
 542   if( t2 == Type::TOP ) return Type::TOP;
 543 
 544   // if both operands are infinity of same sign, the result is NaN; do
 545   // not replace with zero
 546   if (t1->is_finite() && t2->is_finite() && in1 == in2) {
 547     return add_id();
 548   }
 549 
 550   // Either input is BOTTOM ==> the result is the local BOTTOM
 551   const Type *bot = bottom_type();
 552   if( (t1 == bot) || (t2 == bot) ||
 553       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 554     return bot;
 555 
 556   return sub(t1,t2);            // Local flavor of type subtraction
 557 }
 558 
 559 
 560 //=============================================================================
 561 //------------------------------sub--------------------------------------------
 562 // A subtract node differences its two inputs.
 563 const Type* SubHFNode::sub(const Type* t1, const Type* t2) const {
 564   // Half precision floating point subtraction follows the rules of IEEE 754
 565   // applicable to other floating point types.
 566   if (t1->isa_half_float_constant() != nullptr &&
 567       t2->isa_half_float_constant() != nullptr)  {
 568     return TypeH::make(t1->getf() - t2->getf());
 569   } else {
 570     return Type::HALF_FLOAT;
 571   }
 572 }
 573 
 574 //------------------------------Ideal------------------------------------------
 575 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 576   const Type *t2 = phase->type( in(2) );
 577   // Convert "x-c0" into "x+ -c0".
 578   if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
 579     // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
 580   }
 581 
 582   // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
 583   // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
 584   //if( phase->type(in(1)) == TypeF::ZERO )
 585   //return new (phase->C, 2) NegFNode(in(2));
 586 
 587   return nullptr;
 588 }
 589 
 590 //------------------------------sub--------------------------------------------
 591 // A subtract node differences its two inputs.
 592 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
 593   // no folding if one of operands is infinity or NaN, do not do constant folding
 594   if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
 595     return TypeF::make( t1->getf() - t2->getf() );
 596   }
 597   else if( g_isnan(t1->getf()) ) {
 598     return t1;
 599   }
 600   else if( g_isnan(t2->getf()) ) {
 601     return t2;
 602   }
 603   else {
 604     return Type::FLOAT;
 605   }
 606 }
 607 
 608 //=============================================================================
 609 //------------------------------Ideal------------------------------------------
 610 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
 611   const Type *t2 = phase->type( in(2) );
 612   // Convert "x-c0" into "x+ -c0".
 613   if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
 614     // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
 615   }
 616 
 617   // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
 618   // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
 619   //if( phase->type(in(1)) == TypeD::ZERO )
 620   //return new (phase->C, 2) NegDNode(in(2));
 621 
 622   return nullptr;
 623 }
 624 
 625 //------------------------------sub--------------------------------------------
 626 // A subtract node differences its two inputs.
 627 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
 628   // no folding if one of operands is infinity or NaN, do not do constant folding
 629   if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
 630     return TypeD::make( t1->getd() - t2->getd() );
 631   }
 632   else if( g_isnan(t1->getd()) ) {
 633     return t1;
 634   }
 635   else if( g_isnan(t2->getd()) ) {
 636     return t2;
 637   }
 638   else {
 639     return Type::DOUBLE;
 640   }
 641 }
 642 
 643 //=============================================================================
 644 //------------------------------Idealize---------------------------------------
 645 // Unlike SubNodes, compare must still flatten return value to the
 646 // range -1, 0, 1.
 647 // And optimizations like those for (X + Y) - X fail if overflow happens.
 648 Node* CmpNode::Identity(PhaseGVN* phase) {
 649   return this;
 650 }
 651 
 652 CmpNode *CmpNode::make(Node *in1, Node *in2, BasicType bt, bool unsigned_comp) {
 653   switch (bt) {
 654     case T_INT:
 655       if (unsigned_comp) {
 656         return new CmpUNode(in1, in2);
 657       }
 658       return new CmpINode(in1, in2);
 659     case T_LONG:
 660       if (unsigned_comp) {
 661         return new CmpULNode(in1, in2);
 662       }
 663       return new CmpLNode(in1, in2);
 664     case T_OBJECT:
 665     case T_ARRAY:
 666     case T_ADDRESS:
 667     case T_METADATA:
 668       return new CmpPNode(in1, in2);
 669     case T_NARROWOOP:
 670     case T_NARROWKLASS:
 671       return new CmpNNode(in1, in2);
 672     default:
 673       fatal("Not implemented for %s", type2name(bt));
 674   }
 675   return nullptr;
 676 }
 677 
 678 //=============================================================================
 679 //------------------------------cmp--------------------------------------------
 680 // Simplify a CmpI (compare 2 integers) node, based on local information.
 681 // If both inputs are constants, compare them.
 682 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
 683   const TypeInt *r0 = t1->is_int(); // Handy access
 684   const TypeInt *r1 = t2->is_int();
 685 
 686   if( r0->_hi < r1->_lo )       // Range is always low?
 687     return TypeInt::CC_LT;
 688   else if( r0->_lo > r1->_hi )  // Range is always high?
 689     return TypeInt::CC_GT;
 690 
 691   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 692     assert(r0->get_con() == r1->get_con(), "must be equal");
 693     return TypeInt::CC_EQ;      // Equal results.
 694   } else if( r0->_hi == r1->_lo ) // Range is never high?
 695     return TypeInt::CC_LE;
 696   else if( r0->_lo == r1->_hi ) // Range is never low?
 697     return TypeInt::CC_GE;
 698 
 699   const Type* joined = r0->join(r1);
 700   if (joined == Type::TOP) {
 701     return TypeInt::CC_NE;
 702   }
 703   return TypeInt::CC;           // else use worst case results
 704 }
 705 
 706 const Type* CmpINode::Value(PhaseGVN* phase) const {
 707   Node* in1 = in(1);
 708   Node* in2 = in(2);
 709   // If this test is the zero trip guard for a main or post loop, check whether, with the opaque node removed, the test
 710   // would constant fold so the loop is never entered. If so return the type of the test without the opaque node removed:
 711   // make the loop unreachable.
 712   // The reason for this is that the iv phi captures the bounds of the loop and if the loop becomes unreachable, it can
 713   // become top. In that case, the loop must be removed.
 714   // This is safe because:
 715   // - as optimizations proceed, the range of iterations executed by the main loop narrows. If no iterations remain, then
 716   // we're done with optimizations for that loop.
 717   // - the post loop is initially not reachable but as long as there's a main loop, the zero trip guard for the post
 718   // loop takes a phi that merges the pre and main loop's iv and can't constant fold the zero trip guard. Once, the main
 719   // loop is removed, there's no need to preserve the zero trip guard for the post loop anymore.
 720   if (in1 != nullptr && in2 != nullptr) {
 721     uint input = 0;
 722     Node* cmp = nullptr;
 723     BoolTest::mask test;
 724     if (in1->Opcode() == Op_OpaqueZeroTripGuard && phase->type(in1) != Type::TOP) {
 725       cmp = new CmpINode(in1->in(1), in2);
 726       test = ((OpaqueZeroTripGuardNode*)in1)->_loop_entered_mask;
 727     }
 728     if (in2->Opcode() == Op_OpaqueZeroTripGuard && phase->type(in2) != Type::TOP) {
 729       assert(cmp == nullptr, "A cmp with 2 OpaqueZeroTripGuard inputs");
 730       cmp = new CmpINode(in1, in2->in(1));
 731       test = ((OpaqueZeroTripGuardNode*)in2)->_loop_entered_mask;
 732     }
 733     if (cmp != nullptr) {
 734       const Type* cmp_t = cmp->Value(phase);
 735       const Type* t = BoolTest(test).cc2logical(cmp_t);
 736       cmp->destruct(phase);
 737       if (t == TypeInt::ZERO) {
 738         return cmp_t;
 739       }
 740     }
 741   }
 742 
 743   return SubNode::Value(phase);
 744 }
 745 
 746 
 747 // Simplify a CmpU (compare 2 integers) node, based on local information.
 748 // If both inputs are constants, compare them.
 749 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
 750   assert(!t1->isa_ptr(), "obsolete usage of CmpU");
 751 
 752   // comparing two unsigned ints
 753   const TypeInt *r0 = t1->is_int();   // Handy access
 754   const TypeInt *r1 = t2->is_int();
 755 
 756   // Current installed version
 757   // Compare ranges for non-overlap
 758   juint lo0 = r0->_lo;
 759   juint hi0 = r0->_hi;
 760   juint lo1 = r1->_lo;
 761   juint hi1 = r1->_hi;
 762 
 763   // If either one has both negative and positive values,
 764   // it therefore contains both 0 and -1, and since [0..-1] is the
 765   // full unsigned range, the type must act as an unsigned bottom.
 766   bool bot0 = ((jint)(lo0 ^ hi0) < 0);
 767   bool bot1 = ((jint)(lo1 ^ hi1) < 0);
 768 
 769   if (bot0 || bot1) {
 770     // All unsigned values are LE -1 and GE 0.
 771     if (lo0 == 0 && hi0 == 0) {
 772       return TypeInt::CC_LE;            //   0 <= bot
 773     } else if ((jint)lo0 == -1 && (jint)hi0 == -1) {
 774       return TypeInt::CC_GE;            // -1 >= bot
 775     } else if (lo1 == 0 && hi1 == 0) {
 776       return TypeInt::CC_GE;            // bot >= 0
 777     } else if ((jint)lo1 == -1 && (jint)hi1 == -1) {
 778       return TypeInt::CC_LE;            // bot <= -1
 779     }
 780   } else {
 781     // We can use ranges of the form [lo..hi] if signs are the same.
 782     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
 783     // results are reversed, '-' > '+' for unsigned compare
 784     if (hi0 < lo1) {
 785       return TypeInt::CC_LT;            // smaller
 786     } else if (lo0 > hi1) {
 787       return TypeInt::CC_GT;            // greater
 788     } else if (hi0 == lo1 && lo0 == hi1) {
 789       return TypeInt::CC_EQ;            // Equal results
 790     } else if (lo0 >= hi1) {
 791       return TypeInt::CC_GE;
 792     } else if (hi0 <= lo1) {
 793       // Check for special case in Hashtable::get.  (See below.)
 794       if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 795         return TypeInt::CC_LT;
 796       return TypeInt::CC_LE;
 797     }
 798   }
 799   // Check for special case in Hashtable::get - the hash index is
 800   // mod'ed to the table size so the following range check is useless.
 801   // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
 802   // to be positive.
 803   // (This is a gross hack, since the sub method never
 804   // looks at the structure of the node in any other case.)
 805   if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
 806     return TypeInt::CC_LT;
 807 
 808   const Type* joined = r0->join(r1);
 809   if (joined == Type::TOP) {
 810     return TypeInt::CC_NE;
 811   }
 812 
 813   return TypeInt::CC;                   // else use worst case results
 814 }
 815 
 816 const Type* CmpUNode::Value(PhaseGVN* phase) const {
 817   const Type* t = SubNode::Value_common(phase);
 818   if (t != nullptr) {
 819     return t;
 820   }
 821   const Node* in1 = in(1);
 822   const Node* in2 = in(2);
 823   const Type* t1 = phase->type(in1);
 824   const Type* t2 = phase->type(in2);
 825   assert(t1->isa_int(), "CmpU has only Int type inputs");
 826   if (t2 == TypeInt::INT) { // Compare to bottom?
 827     return bottom_type();
 828   }
 829 
 830   const Type* t_sub = sub(t1, t2); // compare based on immediate inputs
 831 
 832   uint in1_op = in1->Opcode();
 833   if (in1_op == Op_AddI || in1_op == Op_SubI) {
 834     // The problem rise when result of AddI(SubI) may overflow
 835     // signed integer value. Let say the input type is
 836     // [256, maxint] then +128 will create 2 ranges due to
 837     // overflow: [minint, minint+127] and [384, maxint].
 838     // But C2 type system keep only 1 type range and as result
 839     // it use general [minint, maxint] for this case which we
 840     // can't optimize.
 841     //
 842     // Make 2 separate type ranges based on types of AddI(SubI) inputs
 843     // and compare results of their compare. If results are the same
 844     // CmpU node can be optimized.
 845     const Node* in11 = in1->in(1);
 846     const Node* in12 = in1->in(2);
 847     const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11);
 848     const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12);
 849     // Skip cases when input types are top or bottom.
 850     if ((t11 != Type::TOP) && (t11 != TypeInt::INT) &&
 851         (t12 != Type::TOP) && (t12 != TypeInt::INT)) {
 852       const TypeInt *r0 = t11->is_int();
 853       const TypeInt *r1 = t12->is_int();
 854       jlong lo_r0 = r0->_lo;
 855       jlong hi_r0 = r0->_hi;
 856       jlong lo_r1 = r1->_lo;
 857       jlong hi_r1 = r1->_hi;
 858       if (in1_op == Op_SubI) {
 859         jlong tmp = hi_r1;
 860         hi_r1 = -lo_r1;
 861         lo_r1 = -tmp;
 862         // Note, for substructing [minint,x] type range
 863         // long arithmetic provides correct overflow answer.
 864         // The confusion come from the fact that in 32-bit
 865         // -minint == minint but in 64-bit -minint == maxint+1.
 866       }
 867       jlong lo_long = lo_r0 + lo_r1;
 868       jlong hi_long = hi_r0 + hi_r1;
 869       int lo_tr1 = min_jint;
 870       int hi_tr1 = (int)hi_long;
 871       int lo_tr2 = (int)lo_long;
 872       int hi_tr2 = max_jint;
 873       bool underflow = lo_long != (jlong)lo_tr2;
 874       bool overflow  = hi_long != (jlong)hi_tr1;
 875       // Use sub(t1, t2) when there is no overflow (one type range)
 876       // or when both overflow and underflow (too complex).
 877       if ((underflow != overflow) && (hi_tr1 < lo_tr2)) {
 878         // Overflow only on one boundary, compare 2 separate type ranges.
 879         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
 880         const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w);
 881         const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w);
 882         const TypeInt* cmp1 = sub(tr1, t2)->is_int();
 883         const TypeInt* cmp2 = sub(tr2, t2)->is_int();
 884         // Compute union, so that cmp handles all possible results from the two cases
 885         const Type* t_cmp = cmp1->meet(cmp2);
 886         // Pick narrowest type, based on overflow computation and on immediate inputs
 887         return t_sub->filter(t_cmp);
 888       }
 889     }
 890   }
 891 
 892   return t_sub;
 893 }
 894 
 895 bool CmpUNode::is_index_range_check() const {
 896   // Check for the "(X ModI Y) CmpU Y" shape
 897   return (in(1)->Opcode() == Op_ModI &&
 898           in(1)->in(2)->eqv_uncast(in(2)));
 899 }
 900 
 901 //------------------------------Idealize---------------------------------------
 902 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
 903   if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
 904     switch (in(1)->Opcode()) {
 905     case Op_CmpU3:              // Collapse a CmpU3/CmpI into a CmpU
 906       return new CmpUNode(in(1)->in(1),in(1)->in(2));
 907     case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
 908       return new CmpLNode(in(1)->in(1),in(1)->in(2));
 909     case Op_CmpUL3:             // Collapse a CmpUL3/CmpI into a CmpUL
 910       return new CmpULNode(in(1)->in(1),in(1)->in(2));
 911     case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
 912       return new CmpFNode(in(1)->in(1),in(1)->in(2));
 913     case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
 914       return new CmpDNode(in(1)->in(1),in(1)->in(2));
 915     //case Op_SubI:
 916       // If (x - y) cannot overflow, then ((x - y) <?> 0)
 917       // can be turned into (x <?> y).
 918       // This is handled (with more general cases) by Ideal_sub_algebra.
 919     }
 920   }
 921   return nullptr;                  // No change
 922 }
 923 
 924 //------------------------------Ideal------------------------------------------
 925 Node* CmpLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 926   Node* a = nullptr;
 927   Node* b = nullptr;
 928   if (is_double_null_check(phase, a, b) && (phase->type(a)->is_zero_type() || phase->type(b)->is_zero_type())) {
 929     // Degraded to a simple null check, use old acmp
 930     return new CmpPNode(a, b);
 931   }
 932   const TypeLong *t2 = phase->type(in(2))->isa_long();
 933   if (Opcode() == Op_CmpL && in(1)->Opcode() == Op_ConvI2L && t2 && t2->is_con()) {
 934     const jlong con = t2->get_con();
 935     if (con >= min_jint && con <= max_jint) {
 936       return new CmpINode(in(1)->in(1), phase->intcon((jint)con));
 937     }
 938   }
 939   return nullptr;
 940 }
 941 
 942 // Match double null check emitted by Compile::optimize_acmp()
 943 bool CmpLNode::is_double_null_check(PhaseGVN* phase, Node*& a, Node*& b) const {
 944   if (in(1)->Opcode() == Op_OrL &&
 945       in(1)->in(1)->Opcode() == Op_CastP2X &&
 946       in(1)->in(2)->Opcode() == Op_CastP2X &&
 947       in(2)->bottom_type()->is_zero_type()) {
 948     assert(EnableValhalla, "unexpected double null check");
 949     a = in(1)->in(1)->in(1);
 950     b = in(1)->in(2)->in(1);
 951     return true;
 952   }
 953   return false;
 954 }
 955 
 956 //------------------------------Value------------------------------------------
 957 const Type* CmpLNode::Value(PhaseGVN* phase) const {
 958   Node* a = nullptr;
 959   Node* b = nullptr;
 960   if (is_double_null_check(phase, a, b) && (!phase->type(a)->maybe_null() || !phase->type(b)->maybe_null())) {
 961     // One operand is never nullptr, emit constant false
 962     return TypeInt::CC_GT;
 963   }
 964   return SubNode::Value(phase);
 965 }
 966 
 967 //=============================================================================
 968 // Simplify a CmpL (compare 2 longs ) node, based on local information.
 969 // If both inputs are constants, compare them.
 970 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
 971   const TypeLong *r0 = t1->is_long(); // Handy access
 972   const TypeLong *r1 = t2->is_long();
 973 
 974   if( r0->_hi < r1->_lo )       // Range is always low?
 975     return TypeInt::CC_LT;
 976   else if( r0->_lo > r1->_hi )  // Range is always high?
 977     return TypeInt::CC_GT;
 978 
 979   else if( r0->is_con() && r1->is_con() ) { // comparing constants?
 980     assert(r0->get_con() == r1->get_con(), "must be equal");
 981     return TypeInt::CC_EQ;      // Equal results.
 982   } else if( r0->_hi == r1->_lo ) // Range is never high?
 983     return TypeInt::CC_LE;
 984   else if( r0->_lo == r1->_hi ) // Range is never low?
 985     return TypeInt::CC_GE;
 986 
 987   const Type* joined = r0->join(r1);
 988   if (joined == Type::TOP) {
 989     return TypeInt::CC_NE;
 990   }
 991 
 992   return TypeInt::CC;           // else use worst case results
 993 }
 994 
 995 
 996 // Simplify a CmpUL (compare 2 unsigned longs) node, based on local information.
 997 // If both inputs are constants, compare them.
 998 const Type* CmpULNode::sub(const Type* t1, const Type* t2) const {
 999   assert(!t1->isa_ptr(), "obsolete usage of CmpUL");
1000 
1001   // comparing two unsigned longs
1002   const TypeLong* r0 = t1->is_long();   // Handy access
1003   const TypeLong* r1 = t2->is_long();
1004 
1005   // Current installed version
1006   // Compare ranges for non-overlap
1007   julong lo0 = r0->_lo;
1008   julong hi0 = r0->_hi;
1009   julong lo1 = r1->_lo;
1010   julong hi1 = r1->_hi;
1011 
1012   // If either one has both negative and positive values,
1013   // it therefore contains both 0 and -1, and since [0..-1] is the
1014   // full unsigned range, the type must act as an unsigned bottom.
1015   bool bot0 = ((jlong)(lo0 ^ hi0) < 0);
1016   bool bot1 = ((jlong)(lo1 ^ hi1) < 0);
1017 
1018   if (bot0 || bot1) {
1019     // All unsigned values are LE -1 and GE 0.
1020     if (lo0 == 0 && hi0 == 0) {
1021       return TypeInt::CC_LE;            //   0 <= bot
1022     } else if ((jlong)lo0 == -1 && (jlong)hi0 == -1) {
1023       return TypeInt::CC_GE;            // -1 >= bot
1024     } else if (lo1 == 0 && hi1 == 0) {
1025       return TypeInt::CC_GE;            // bot >= 0
1026     } else if ((jlong)lo1 == -1 && (jlong)hi1 == -1) {
1027       return TypeInt::CC_LE;            // bot <= -1
1028     }
1029   } else {
1030     // We can use ranges of the form [lo..hi] if signs are the same.
1031     assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
1032     // results are reversed, '-' > '+' for unsigned compare
1033     if (hi0 < lo1) {
1034       return TypeInt::CC_LT;            // smaller
1035     } else if (lo0 > hi1) {
1036       return TypeInt::CC_GT;            // greater
1037     } else if (hi0 == lo1 && lo0 == hi1) {
1038       return TypeInt::CC_EQ;            // Equal results
1039     } else if (lo0 >= hi1) {
1040       return TypeInt::CC_GE;
1041     } else if (hi0 <= lo1) {
1042       return TypeInt::CC_LE;
1043     }
1044   }
1045 
1046   const Type* joined = r0->join(r1);
1047   if (joined == Type::TOP) {
1048     return TypeInt::CC_NE;
1049   }
1050 
1051   return TypeInt::CC;                   // else use worst case results
1052 }
1053 
1054 //=============================================================================
1055 //------------------------------sub--------------------------------------------
1056 // Simplify an CmpP (compare 2 pointers) node, based on local information.
1057 // If both inputs are constants, compare them.
1058 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
1059   const TypePtr *r0 = t1->is_ptr(); // Handy access
1060   const TypePtr *r1 = t2->is_ptr();
1061 
1062   // Undefined inputs makes for an undefined result
1063   if( TypePtr::above_centerline(r0->_ptr) ||
1064       TypePtr::above_centerline(r1->_ptr) )
1065     return Type::TOP;
1066 
1067   if (r0 == r1 && r0->singleton()) {
1068     // Equal pointer constants (klasses, nulls, etc.)
1069     return TypeInt::CC_EQ;
1070   }
1071 
1072   // See if it is 2 unrelated classes.
1073   const TypeOopPtr* p0 = r0->isa_oopptr();
1074   const TypeOopPtr* p1 = r1->isa_oopptr();
1075   const TypeKlassPtr* k0 = r0->isa_klassptr();
1076   const TypeKlassPtr* k1 = r1->isa_klassptr();
1077   if ((p0 && p1) || (k0 && k1)) {
1078     if (p0 && p1) {
1079       Node* in1 = in(1)->uncast();
1080       Node* in2 = in(2)->uncast();
1081       AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1);
1082       AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2);
1083       if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, nullptr)) {
1084         return TypeInt::CC_GT;  // different pointers
1085       }
1086     }
1087     bool    xklass0 = p0 ? p0->klass_is_exact() : k0->klass_is_exact();
1088     bool    xklass1 = p1 ? p1->klass_is_exact() : k1->klass_is_exact();
1089     bool unrelated_classes = false;
1090 
1091     if ((p0 && p0->is_same_java_type_as(p1)) ||
1092         (k0 && k0->is_same_java_type_as(k1))) {
1093     } else if ((p0 && !p1->maybe_java_subtype_of(p0) && !p0->maybe_java_subtype_of(p1)) ||
1094                (k0 && !k1->maybe_java_subtype_of(k0) && !k0->maybe_java_subtype_of(k1))) {
1095       unrelated_classes = true;
1096     } else if ((p0 && !p1->maybe_java_subtype_of(p0)) ||
1097                (k0 && !k1->maybe_java_subtype_of(k0))) {
1098       unrelated_classes = xklass1;
1099     } else if ((p0 && !p0->maybe_java_subtype_of(p1)) ||
1100                (k0 && !k0->maybe_java_subtype_of(k1))) {
1101       unrelated_classes = xklass0;
1102     }
1103     if (!unrelated_classes) {
1104       // Handle inline type arrays
1105       if ((r0->flat_in_array() && r1->not_flat_in_array()) ||
1106           (r1->flat_in_array() && r0->not_flat_in_array())) {
1107         // One type is in flat arrays but the other type is not. Must be unrelated.
1108         unrelated_classes = true;
1109       } else if ((r0->is_not_flat() && r1->is_flat()) ||
1110                  (r1->is_not_flat() && r0->is_flat())) {
1111         // One type is a non-flat array and the other type is a flat array. Must be unrelated.
1112         unrelated_classes = true;
1113       } else if ((r0->is_not_null_free() && r1->is_null_free()) ||
1114                  (r1->is_not_null_free() && r0->is_null_free())) {
1115         // One type is a nullable array and the other type is a null-free array. Must be unrelated.
1116         unrelated_classes = true;
1117       }
1118     }
1119     if (unrelated_classes) {
1120       // The oops classes are known to be unrelated. If the joined PTRs of
1121       // two oops is not Null and not Bottom, then we are sure that one
1122       // of the two oops is non-null, and the comparison will always fail.
1123       TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
1124       if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
1125         return TypeInt::CC_GT;
1126       }
1127     }
1128   }
1129 
1130   // Known constants can be compared exactly
1131   // Null can be distinguished from any NotNull pointers
1132   // Unknown inputs makes an unknown result
1133   if( r0->singleton() ) {
1134     intptr_t bits0 = r0->get_con();
1135     if( r1->singleton() )
1136       return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1137     return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1138   } else if( r1->singleton() ) {
1139     intptr_t bits1 = r1->get_con();
1140     return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1141   } else
1142     return TypeInt::CC;
1143 }
1144 
1145 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
1146   // Return the klass node for (indirect load from OopHandle)
1147   //   LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
1148   //   or null if not matching.
1149   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1150     n = bs->step_over_gc_barrier(n);
1151 
1152   if (n->Opcode() != Op_LoadP) return nullptr;
1153 
1154   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
1155   if (!tp || tp->instance_klass() != phase->C->env()->Class_klass()) return nullptr;
1156 
1157   Node* adr = n->in(MemNode::Address);
1158   // First load from OopHandle: ((OopHandle)mirror)->resolve(); may need barrier.
1159   if (adr->Opcode() != Op_LoadP || !phase->type(adr)->isa_rawptr()) return nullptr;
1160   adr = adr->in(MemNode::Address);
1161 
1162   intptr_t off = 0;
1163   Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
1164   if (k == nullptr)  return nullptr;
1165   const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
1166   if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return nullptr;
1167 
1168   // We've found the klass node of a Java mirror load.
1169   return k;
1170 }
1171 
1172 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
1173   // for ConP(Foo.class) return ConP(Foo.klass)
1174   // otherwise return null
1175   if (!n->is_Con()) return nullptr;
1176 
1177   const TypeInstPtr* tp = phase->type(n)->isa_instptr();
1178   if (!tp) return nullptr;
1179 
1180   ciType* mirror_type = tp->java_mirror_type();
1181   // TypeInstPtr::java_mirror_type() returns non-null for compile-
1182   // time Class constants only.
1183   if (!mirror_type) return nullptr;
1184 
1185   // x.getClass() == int.class can never be true (for all primitive types)
1186   // Return a ConP(null) node for this case.
1187   if (mirror_type->is_classless()) {
1188     return phase->makecon(TypePtr::NULL_PTR);
1189   }
1190 
1191   // return the ConP(Foo.klass)
1192   assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
1193   return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass(), Type::trust_interfaces));
1194 }
1195 
1196 //------------------------------Ideal------------------------------------------
1197 // Normalize comparisons between Java mirror loads to compare the klass instead.
1198 //
1199 // Also check for the case of comparing an unknown klass loaded from the primary
1200 // super-type array vs a known klass with no subtypes.  This amounts to
1201 // checking to see an unknown klass subtypes a known klass with no subtypes;
1202 // this only happens on an exact match.  We can shorten this test by 1 load.
1203 Node* CmpPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1204   // TODO 8284443 in(1) could be cast?
1205   if (in(1)->is_InlineType() && phase->type(in(2))->is_zero_type()) {
1206     // Null checking a scalarized but nullable inline type. Check the null marker
1207     // input instead of the oop input to avoid keeping buffer allocations alive.
1208     return new CmpINode(in(1)->as_InlineType()->get_null_marker(), phase->intcon(0));
1209   }
1210 
1211   // Normalize comparisons between Java mirrors into comparisons of the low-
1212   // level klass, where a dependent load could be shortened.
1213   //
1214   // The new pattern has a nice effect of matching the same pattern used in the
1215   // fast path of instanceof/checkcast/Class.isInstance(), which allows
1216   // redundant exact type check be optimized away by GVN.
1217   // For example, in
1218   //   if (x.getClass() == Foo.class) {
1219   //     Foo foo = (Foo) x;
1220   //     // ... use a ...
1221   //   }
1222   // a CmpPNode could be shared between if_acmpne and checkcast
1223   {
1224     Node* k1 = isa_java_mirror_load(phase, in(1));
1225     Node* k2 = isa_java_mirror_load(phase, in(2));
1226     Node* conk2 = isa_const_java_mirror(phase, in(2));
1227 
1228     // TODO 8366668 add a test for this. Improve this condition
1229     bool doIt = (conk2 && !phase->type(conk2)->isa_aryklassptr());
1230     if (k1 && (k2 || conk2) && doIt) {
1231       Node* lhs = k1;
1232       Node* rhs = (k2 != nullptr) ? k2 : conk2;
1233       set_req_X(1, lhs, phase);
1234       set_req_X(2, rhs, phase);
1235       return this;
1236     }
1237   }
1238 
1239   // Constant pointer on right?
1240   const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
1241   if (t2 == nullptr || !t2->klass_is_exact())
1242     return nullptr;
1243   // Get the constant klass we are comparing to.
1244   ciKlass* superklass = t2->exact_klass();
1245 
1246   // Now check for LoadKlass on left.
1247   Node* ldk1 = in(1);
1248   if (ldk1->is_DecodeNKlass()) {
1249     ldk1 = ldk1->in(1);
1250     if (ldk1->Opcode() != Op_LoadNKlass )
1251       return nullptr;
1252   } else if (ldk1->Opcode() != Op_LoadKlass )
1253     return nullptr;
1254   // Take apart the address of the LoadKlass:
1255   Node* adr1 = ldk1->in(MemNode::Address);
1256   intptr_t con2 = 0;
1257   Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
1258   if (ldk2 == nullptr)
1259     return nullptr;
1260   if (con2 == oopDesc::klass_offset_in_bytes()) {
1261     // We are inspecting an object's concrete class.
1262     // Short-circuit the check if the query is abstract.
1263     if (superklass->is_interface() ||
1264         superklass->is_abstract()) {
1265       // Make it come out always false:
1266       this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
1267       return this;
1268     }
1269   }
1270 
1271   // Check for a LoadKlass from primary supertype array.
1272   // Any nested loadklass from loadklass+con must be from the p.s. array.
1273   if (ldk2->is_DecodeNKlass()) {
1274     // Keep ldk2 as DecodeN since it could be used in CmpP below.
1275     if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
1276       return nullptr;
1277   } else if (ldk2->Opcode() != Op_LoadKlass)
1278     return nullptr;
1279 
1280   // Verify that we understand the situation
1281   if (con2 != (intptr_t) superklass->super_check_offset())
1282     return nullptr;                // Might be element-klass loading from array klass
1283 
1284   // Do not fold the subtype check to an array klass pointer comparison for null-able inline type arrays
1285   // because null-free [LMyValue <: null-able [LMyValue but the klasses are different. Perform a full test.
1286   if (superklass->is_obj_array_klass() && !superklass->as_array_klass()->is_elem_null_free() &&
1287       superklass->as_array_klass()->element_klass()->is_inlinetype()) {
1288     return nullptr;
1289   }
1290 
1291   // If 'superklass' has no subklasses and is not an interface, then we are
1292   // assured that the only input which will pass the type check is
1293   // 'superklass' itself.
1294   //
1295   // We could be more liberal here, and allow the optimization on interfaces
1296   // which have a single implementor.  This would require us to increase the
1297   // expressiveness of the add_dependency() mechanism.
1298   // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.
1299 
1300   // Object arrays must have their base element have no subtypes
1301   while (superklass->is_obj_array_klass()) {
1302     ciType* elem = superklass->as_obj_array_klass()->element_type();
1303     superklass = elem->as_klass();
1304   }
1305   if (superklass->is_instance_klass()) {
1306     ciInstanceKlass* ik = superklass->as_instance_klass();
1307     if (ik->has_subklass() || ik->is_interface())  return nullptr;
1308     // Add a dependency if there is a chance that a subclass will be added later.
1309     if (!ik->is_final()) {
1310       phase->C->dependencies()->assert_leaf_type(ik);
1311     }
1312   }
1313 
1314   // Bypass the dependent load, and compare directly
1315   this->set_req_X(1, ldk2, phase);
1316 
1317   return this;
1318 }
1319 
1320 //=============================================================================
1321 //------------------------------sub--------------------------------------------
1322 // Simplify an CmpN (compare 2 pointers) node, based on local information.
1323 // If both inputs are constants, compare them.
1324 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
1325   ShouldNotReachHere();
1326   return bottom_type();
1327 }
1328 
1329 //------------------------------Ideal------------------------------------------
1330 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1331   return nullptr;
1332 }
1333 
1334 //=============================================================================
1335 //------------------------------Value------------------------------------------
1336 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1337 // If both inputs are constants, compare them.
1338 const Type* CmpFNode::Value(PhaseGVN* phase) const {
1339   const Node* in1 = in(1);
1340   const Node* in2 = in(2);
1341   // Either input is TOP ==> the result is TOP
1342   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1343   if( t1 == Type::TOP ) return Type::TOP;
1344   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1345   if( t2 == Type::TOP ) return Type::TOP;
1346 
1347   // Not constants?  Don't know squat - even if they are the same
1348   // value!  If they are NaN's they compare to LT instead of EQ.
1349   const TypeF *tf1 = t1->isa_float_constant();
1350   const TypeF *tf2 = t2->isa_float_constant();
1351   if( !tf1 || !tf2 ) return TypeInt::CC;
1352 
1353   // This implements the Java bytecode fcmpl, so unordered returns -1.
1354   if( tf1->is_nan() || tf2->is_nan() )
1355     return TypeInt::CC_LT;
1356 
1357   if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
1358   if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
1359   assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
1360   return TypeInt::CC_EQ;
1361 }
1362 
1363 
1364 //=============================================================================
1365 //------------------------------Value------------------------------------------
1366 // Simplify an CmpD (compare 2 doubles ) node, based on local information.
1367 // If both inputs are constants, compare them.
1368 const Type* CmpDNode::Value(PhaseGVN* phase) const {
1369   const Node* in1 = in(1);
1370   const Node* in2 = in(2);
1371   // Either input is TOP ==> the result is TOP
1372   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
1373   if( t1 == Type::TOP ) return Type::TOP;
1374   const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
1375   if( t2 == Type::TOP ) return Type::TOP;
1376 
1377   // Not constants?  Don't know squat - even if they are the same
1378   // value!  If they are NaN's they compare to LT instead of EQ.
1379   const TypeD *td1 = t1->isa_double_constant();
1380   const TypeD *td2 = t2->isa_double_constant();
1381   if( !td1 || !td2 ) return TypeInt::CC;
1382 
1383   // This implements the Java bytecode dcmpl, so unordered returns -1.
1384   if( td1->is_nan() || td2->is_nan() )
1385     return TypeInt::CC_LT;
1386 
1387   if( td1->_d < td2->_d ) return TypeInt::CC_LT;
1388   if( td1->_d > td2->_d ) return TypeInt::CC_GT;
1389   assert( td1->_d == td2->_d, "do not understand FP behavior" );
1390   return TypeInt::CC_EQ;
1391 }
1392 
1393 //------------------------------Ideal------------------------------------------
1394 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
1395   // Check if we can change this to a CmpF and remove a ConvD2F operation.
1396   // Change  (CMPD (F2D (float)) (ConD value))
1397   // To      (CMPF      (float)  (ConF value))
1398   // Valid when 'value' does not lose precision as a float.
1399   // Benefits: eliminates conversion, does not require 24-bit mode
1400 
1401   // NaNs prevent commuting operands.  This transform works regardless of the
1402   // order of ConD and ConvF2D inputs by preserving the original order.
1403   int idx_f2d = 1;              // ConvF2D on left side?
1404   if( in(idx_f2d)->Opcode() != Op_ConvF2D )
1405     idx_f2d = 2;                // No, swap to check for reversed args
1406   int idx_con = 3-idx_f2d;      // Check for the constant on other input
1407 
1408   if( ConvertCmpD2CmpF &&
1409       in(idx_f2d)->Opcode() == Op_ConvF2D &&
1410       in(idx_con)->Opcode() == Op_ConD ) {
1411     const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
1412     double t2_value_as_double = t2->_d;
1413     float  t2_value_as_float  = (float)t2_value_as_double;
1414     if( t2_value_as_double == (double)t2_value_as_float ) {
1415       // Test value can be represented as a float
1416       // Eliminate the conversion to double and create new comparison
1417       Node *new_in1 = in(idx_f2d)->in(1);
1418       Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
1419       if( idx_f2d != 1 ) {      // Must flip args to match original order
1420         Node *tmp = new_in1;
1421         new_in1 = new_in2;
1422         new_in2 = tmp;
1423       }
1424       CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
1425         ? new CmpF3Node( new_in1, new_in2 )
1426         : new CmpFNode ( new_in1, new_in2 ) ;
1427       return new_cmp;           // Changed to CmpFNode
1428     }
1429     // Testing value required the precision of a double
1430   }
1431   return nullptr;                  // No change
1432 }
1433 
1434 //=============================================================================
1435 //------------------------------Value------------------------------------------
1436 const Type* FlatArrayCheckNode::Value(PhaseGVN* phase) const {
1437   bool all_not_flat = true;
1438   for (uint i = ArrayOrKlass; i < req(); ++i) {
1439     const Type* t = phase->type(in(i));
1440     if (t == Type::TOP) {
1441       return Type::TOP;
1442     }
1443     if (t->is_ptr()->is_flat()) {
1444       // One of the input arrays is flat, check always passes
1445       return TypeInt::CC_EQ;
1446     } else if (!t->is_ptr()->is_not_flat()) {
1447       // One of the input arrays might be flat
1448       all_not_flat = false;
1449     }
1450   }
1451   if (all_not_flat) {
1452     // None of the input arrays can be flat, check always fails
1453     return TypeInt::CC_GT;
1454   }
1455   return TypeInt::CC;
1456 }
1457 
1458 //------------------------------Ideal------------------------------------------
1459 Node* FlatArrayCheckNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1460   bool changed = false;
1461   // Remove inputs that are known to be non-flat
1462   for (uint i = ArrayOrKlass; i < req(); ++i) {
1463     const Type* t = phase->type(in(i));
1464     if (t->isa_ptr() && t->is_ptr()->is_not_flat()) {
1465       del_req(i--);
1466       changed = true;
1467     }
1468   }
1469   return changed ? this : nullptr;
1470 }
1471 
1472 //=============================================================================
1473 //------------------------------cc2logical-------------------------------------
1474 // Convert a condition code type to a logical type
1475 const Type *BoolTest::cc2logical( const Type *CC ) const {
1476   if( CC == Type::TOP ) return Type::TOP;
1477   if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
1478   const TypeInt *ti = CC->is_int();
1479   if( ti->is_con() ) {          // Only 1 kind of condition codes set?
1480     // Match low order 2 bits
1481     int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
1482     if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
1483     return TypeInt::make(tmp);       // Boolean result
1484   }
1485 
1486   if( CC == TypeInt::CC_GE ) {
1487     if( _test == ge ) return TypeInt::ONE;
1488     if( _test == lt ) return TypeInt::ZERO;
1489   }
1490   if( CC == TypeInt::CC_LE ) {
1491     if( _test == le ) return TypeInt::ONE;
1492     if( _test == gt ) return TypeInt::ZERO;
1493   }
1494   if( CC == TypeInt::CC_NE ) {
1495     if( _test == ne ) return TypeInt::ONE;
1496     if( _test == eq ) return TypeInt::ZERO;
1497   }
1498 
1499   return TypeInt::BOOL;
1500 }
1501 
1502 //------------------------------dump_spec-------------------------------------
1503 // Print special per-node info
1504 void BoolTest::dump_on(outputStream *st) const {
1505   const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
1506   st->print("%s", msg[_test]);
1507 }
1508 
1509 // Returns the logical AND of two tests (or 'never' if both tests can never be true).
1510 // For example, a test for 'le' followed by a test for 'lt' is equivalent with 'lt'.
1511 BoolTest::mask BoolTest::merge(BoolTest other) const {
1512   const mask res[illegal+1][illegal+1] = {
1513     // eq,      gt,      of,      lt,      ne,      le,      nof,     ge,      never,   illegal
1514       {eq,      never,   illegal, never,   never,   eq,      illegal, eq,      never,   illegal},  // eq
1515       {never,   gt,      illegal, never,   gt,      never,   illegal, gt,      never,   illegal},  // gt
1516       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // of
1517       {never,   never,   illegal, lt,      lt,      lt,      illegal, never,   never,   illegal},  // lt
1518       {never,   gt,      illegal, lt,      ne,      lt,      illegal, gt,      never,   illegal},  // ne
1519       {eq,      never,   illegal, lt,      lt,      le,      illegal, eq,      never,   illegal},  // le
1520       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, never,   illegal},  // nof
1521       {eq,      gt,      illegal, never,   gt,      eq,      illegal, ge,      never,   illegal},  // ge
1522       {never,   never,   never,   never,   never,   never,   never,   never,   never,   illegal},  // never
1523       {illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal, illegal}}; // illegal
1524   return res[_test][other._test];
1525 }
1526 
1527 //=============================================================================
1528 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
1529 uint BoolNode::size_of() const { return sizeof(BoolNode); }
1530 
1531 //------------------------------operator==-------------------------------------
1532 bool BoolNode::cmp( const Node &n ) const {
1533   const BoolNode *b = (const BoolNode *)&n; // Cast up
1534   return (_test._test == b->_test._test);
1535 }
1536 
1537 //-------------------------------make_predicate--------------------------------
1538 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
1539   if (test_value->is_Con())   return test_value;
1540   if (test_value->is_Bool())  return test_value;
1541   if (test_value->is_CMove() &&
1542       test_value->in(CMoveNode::Condition)->is_Bool()) {
1543     BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
1544     const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
1545     const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
1546     if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
1547       return bol;
1548     } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
1549       return phase->transform( bol->negate(phase) );
1550     }
1551     // Else fall through.  The CMove gets in the way of the test.
1552     // It should be the case that make_predicate(bol->as_int_value()) == bol.
1553   }
1554   Node* cmp = new CmpINode(test_value, phase->intcon(0));
1555   cmp = phase->transform(cmp);
1556   Node* bol = new BoolNode(cmp, BoolTest::ne);
1557   return phase->transform(bol);
1558 }
1559 
1560 //--------------------------------as_int_value---------------------------------
1561 Node* BoolNode::as_int_value(PhaseGVN* phase) {
1562   // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
1563   Node* cmov = CMoveNode::make(this, phase->intcon(0), phase->intcon(1), TypeInt::BOOL);
1564   return phase->transform(cmov);
1565 }
1566 
1567 //----------------------------------negate-------------------------------------
1568 BoolNode* BoolNode::negate(PhaseGVN* phase) {
1569   return new BoolNode(in(1), _test.negate());
1570 }
1571 
1572 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub
1573 // overflows and we can prove that C is not in the two resulting ranges.
1574 // This optimization is similar to the one performed by CmpUNode::Value().
1575 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, int cmp_op,
1576                           int cmp1_op, const TypeInt* cmp2_type) {
1577   // Only optimize eq/ne integer comparison of add/sub
1578   if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1579      (cmp_op == Op_CmpI) && (cmp1_op == Op_AddI || cmp1_op == Op_SubI)) {
1580     // Skip cases were inputs of add/sub are not integers or of bottom type
1581     const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int();
1582     const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int();
1583     if ((r0 != nullptr) && (r0 != TypeInt::INT) &&
1584         (r1 != nullptr) && (r1 != TypeInt::INT) &&
1585         (cmp2_type != TypeInt::INT)) {
1586       // Compute exact (long) type range of add/sub result
1587       jlong lo_long = r0->_lo;
1588       jlong hi_long = r0->_hi;
1589       if (cmp1_op == Op_AddI) {
1590         lo_long += r1->_lo;
1591         hi_long += r1->_hi;
1592       } else {
1593         lo_long -= r1->_hi;
1594         hi_long -= r1->_lo;
1595       }
1596       // Check for over-/underflow by casting to integer
1597       int lo_int = (int)lo_long;
1598       int hi_int = (int)hi_long;
1599       bool underflow = lo_long != (jlong)lo_int;
1600       bool overflow  = hi_long != (jlong)hi_int;
1601       if ((underflow != overflow) && (hi_int < lo_int)) {
1602         // Overflow on one boundary, compute resulting type ranges:
1603         // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT]
1604         int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here
1605         const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w);
1606         const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w);
1607         // Compare second input of cmp to both type ranges
1608         const Type* sub_tr1 = cmp->sub(tr1, cmp2_type);
1609         const Type* sub_tr2 = cmp->sub(tr2, cmp2_type);
1610         if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) {
1611           // The result of the add/sub will never equal cmp2. Replace BoolNode
1612           // by false (0) if it tests for equality and by true (1) otherwise.
1613           return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1);
1614         }
1615       }
1616     }
1617   }
1618   return nullptr;
1619 }
1620 
1621 static bool is_counted_loop_cmp(Node *cmp) {
1622   Node *n = cmp->in(1)->in(1);
1623   return n != nullptr &&
1624          n->is_Phi() &&
1625          n->in(0) != nullptr &&
1626          n->in(0)->is_CountedLoop() &&
1627          n->in(0)->as_CountedLoop()->phi() == n;
1628 }
1629 
1630 //------------------------------Ideal------------------------------------------
1631 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1632   // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
1633   // This moves the constant to the right.  Helps value-numbering.
1634   Node *cmp = in(1);
1635   if( !cmp->is_Sub() ) return nullptr;
1636   int cop = cmp->Opcode();
1637   if( cop == Op_FastLock || cop == Op_FastUnlock ||
1638       cmp->is_SubTypeCheck() || cop == Op_VectorTest ) {
1639     return nullptr;
1640   }
1641   Node *cmp1 = cmp->in(1);
1642   Node *cmp2 = cmp->in(2);
1643   if( !cmp1 ) return nullptr;
1644 
1645   if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) {
1646     return nullptr;
1647   }
1648 
1649   const int cmp1_op = cmp1->Opcode();
1650   const int cmp2_op = cmp2->Opcode();
1651 
1652   // Constant on left?
1653   Node *con = cmp1;
1654   // Move constants to the right of compare's to canonicalize.
1655   // Do not muck with Opaque1 nodes, as this indicates a loop
1656   // guard that cannot change shape.
1657   if (con->is_Con() && !cmp2->is_Con() && cmp2_op != Op_OpaqueZeroTripGuard &&
1658       // Because of NaN's, CmpD and CmpF are not commutative
1659       cop != Op_CmpD && cop != Op_CmpF &&
1660       // Protect against swapping inputs to a compare when it is used by a
1661       // counted loop exit, which requires maintaining the loop-limit as in(2)
1662       !is_counted_loop_exit_test() ) {
1663     // Ok, commute the constant to the right of the cmp node.
1664     // Clone the Node, getting a new Node of the same class
1665     cmp = cmp->clone();
1666     // Swap inputs to the clone
1667     cmp->swap_edges(1, 2);
1668     cmp = phase->transform( cmp );
1669     return new BoolNode( cmp, _test.commute() );
1670   }
1671 
1672   // Change "bool eq/ne (cmp (cmove (bool tst (cmp2)) 1 0) 0)" into "bool tst/~tst (cmp2)"
1673   if (cop == Op_CmpI &&
1674       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1675       cmp1_op == Op_CMoveI && cmp2->find_int_con(1) == 0) {
1676     // 0 should be on the true branch
1677     if (cmp1->in(CMoveNode::Condition)->is_Bool() &&
1678         cmp1->in(CMoveNode::IfTrue)->find_int_con(1) == 0 &&
1679         cmp1->in(CMoveNode::IfFalse)->find_int_con(0) != 0) {
1680       BoolNode* target = cmp1->in(CMoveNode::Condition)->as_Bool();
1681       return new BoolNode(target->in(1),
1682                           (_test._test == BoolTest::eq) ? target->_test._test :
1683                                                           target->_test.negate());
1684     }
1685   }
1686 
1687   // Change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)".
1688   if (cop == Op_CmpI &&
1689       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1690       cmp1_op == Op_AndI && cmp2_op == Op_ConI &&
1691       cmp1->in(2)->Opcode() == Op_ConI) {
1692     const TypeInt *t12 = phase->type(cmp2)->isa_int();
1693     const TypeInt *t112 = phase->type(cmp1->in(2))->isa_int();
1694     if (t12 && t12->is_con() && t112 && t112->is_con() &&
1695         t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) {
1696       Node *ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1697       return new BoolNode(ncmp, _test.negate());
1698     }
1699   }
1700 
1701   // Same for long type: change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)".
1702   if (cop == Op_CmpL &&
1703       (_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1704       cmp1_op == Op_AndL && cmp2_op == Op_ConL &&
1705       cmp1->in(2)->Opcode() == Op_ConL) {
1706     const TypeLong *t12 = phase->type(cmp2)->isa_long();
1707     const TypeLong *t112 = phase->type(cmp1->in(2))->isa_long();
1708     if (t12 && t12->is_con() && t112 && t112->is_con() &&
1709         t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) {
1710       Node *ncmp = phase->transform(new CmpLNode(cmp1, phase->longcon(0)));
1711       return new BoolNode(ncmp, _test.negate());
1712     }
1713   }
1714 
1715   // Change "cmp (add X min_jint) (add Y min_jint)" into "cmpu X Y"
1716   // and    "cmp (add X min_jint) c" into "cmpu X (c + min_jint)"
1717   if (cop == Op_CmpI &&
1718       cmp1_op == Op_AddI &&
1719       phase->type(cmp1->in(2)) == TypeInt::MIN &&
1720       !is_cloop_condition(this)) {
1721     if (cmp2_op == Op_ConI) {
1722       Node* ncmp2 = phase->intcon(java_add(cmp2->get_int(), min_jint));
1723       Node* ncmp = phase->transform(new CmpUNode(cmp1->in(1), ncmp2));
1724       return new BoolNode(ncmp, _test._test);
1725     } else if (cmp2_op == Op_AddI &&
1726                phase->type(cmp2->in(2)) == TypeInt::MIN &&
1727                !is_cloop_condition(this)) {
1728       Node* ncmp = phase->transform(new CmpUNode(cmp1->in(1), cmp2->in(1)));
1729       return new BoolNode(ncmp, _test._test);
1730     }
1731   }
1732 
1733   // Change "cmp (add X min_jlong) (add Y min_jlong)" into "cmpu X Y"
1734   // and    "cmp (add X min_jlong) c" into "cmpu X (c + min_jlong)"
1735   if (cop == Op_CmpL &&
1736       cmp1_op == Op_AddL &&
1737       phase->type(cmp1->in(2)) == TypeLong::MIN &&
1738       !is_cloop_condition(this)) {
1739     if (cmp2_op == Op_ConL) {
1740       Node* ncmp2 = phase->longcon(java_add(cmp2->get_long(), min_jlong));
1741       Node* ncmp = phase->transform(new CmpULNode(cmp1->in(1), ncmp2));
1742       return new BoolNode(ncmp, _test._test);
1743     } else if (cmp2_op == Op_AddL &&
1744                phase->type(cmp2->in(2)) == TypeLong::MIN &&
1745                !is_cloop_condition(this)) {
1746       Node* ncmp = phase->transform(new CmpULNode(cmp1->in(1), cmp2->in(1)));
1747       return new BoolNode(ncmp, _test._test);
1748     }
1749   }
1750 
1751   // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
1752   // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
1753   // test instead.
1754   const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
1755   if (cmp2_type == nullptr)  return nullptr;
1756   Node* j_xor = cmp1;
1757   if( cmp2_type == TypeInt::ZERO &&
1758       cmp1_op == Op_XorI &&
1759       j_xor->in(1) != j_xor &&          // An xor of itself is dead
1760       phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
1761       phase->type( j_xor->in(2) ) == TypeInt::ONE &&
1762       (_test._test == BoolTest::eq ||
1763        _test._test == BoolTest::ne) ) {
1764     Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2));
1765     return new BoolNode( ncmp, _test.negate() );
1766   }
1767 
1768   // Transform: "((x & (m - 1)) <u m)" or "(((m - 1) & x) <u m)" into "(m >u 0)"
1769   // This is case [CMPU_MASK] which is further described at the method comment of BoolNode::Value_cmpu_and_mask().
1770   if (cop == Op_CmpU && _test._test == BoolTest::lt && cmp1_op == Op_AndI) {
1771     Node* m = cmp2; // RHS: m
1772     for (int add_idx = 1; add_idx <= 2; add_idx++) { // LHS: "(m + (-1)) & x" or "x & (m + (-1))"?
1773       Node* maybe_m_minus_1 = cmp1->in(add_idx);
1774       if (maybe_m_minus_1->Opcode() == Op_AddI &&
1775           maybe_m_minus_1->in(2)->find_int_con(0) == -1 &&
1776           maybe_m_minus_1->in(1) == m) {
1777         Node* m_cmpu_0 = phase->transform(new CmpUNode(m, phase->intcon(0)));
1778         return new BoolNode(m_cmpu_0, BoolTest::gt);
1779       }
1780     }
1781   }
1782 
1783   // Change x u< 1 or x u<= 0 to x == 0
1784   // and    x u> 0 or u>= 1   to x != 0
1785   if (cop == Op_CmpU &&
1786       cmp1_op != Op_LoadRange &&
1787       (((_test._test == BoolTest::lt || _test._test == BoolTest::ge) &&
1788         cmp2->find_int_con(-1) == 1) ||
1789        ((_test._test == BoolTest::le || _test._test == BoolTest::gt) &&
1790         cmp2->find_int_con(-1) == 0))) {
1791     Node* ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0)));
1792     return new BoolNode(ncmp, _test.is_less() ? BoolTest::eq : BoolTest::ne);
1793   }
1794 
1795   // Change (arraylength <= 0) or (arraylength == 0)
1796   //   into (arraylength u<= 0)
1797   // Also change (arraylength != 0) into (arraylength u> 0)
1798   // The latter version matches the code pattern generated for
1799   // array range checks, which will more likely be optimized later.
1800   if (cop == Op_CmpI &&
1801       cmp1_op == Op_LoadRange &&
1802       cmp2->find_int_con(-1) == 0) {
1803     if (_test._test == BoolTest::le || _test._test == BoolTest::eq) {
1804       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1805       return new BoolNode(ncmp, BoolTest::le);
1806     } else if (_test._test == BoolTest::ne) {
1807       Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2));
1808       return new BoolNode(ncmp, BoolTest::gt);
1809     }
1810   }
1811 
1812   // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
1813   // This is a standard idiom for branching on a boolean value.
1814   Node *c2b = cmp1;
1815   if( cmp2_type == TypeInt::ZERO &&
1816       cmp1_op == Op_Conv2B &&
1817       (_test._test == BoolTest::eq ||
1818        _test._test == BoolTest::ne) ) {
1819     Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
1820        ? (Node*)new CmpINode(c2b->in(1),cmp2)
1821        : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
1822     );
1823     return new BoolNode( ncmp, _test._test );
1824   }
1825 
1826   // Comparing a SubI against a zero is equal to comparing the SubI
1827   // arguments directly.  This only works for eq and ne comparisons
1828   // due to possible integer overflow.
1829   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1830         (cop == Op_CmpI) &&
1831         (cmp1_op == Op_SubI) &&
1832         ( cmp2_type == TypeInt::ZERO ) ) {
1833     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2)));
1834     return new BoolNode( ncmp, _test._test );
1835   }
1836 
1837   // Same as above but with and AddI of a constant
1838   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1839       cop == Op_CmpI &&
1840       cmp1_op == Op_AddI &&
1841       cmp1->in(2) != nullptr &&
1842       phase->type(cmp1->in(2))->isa_int() &&
1843       phase->type(cmp1->in(2))->is_int()->is_con() &&
1844       cmp2_type == TypeInt::ZERO &&
1845       !is_counted_loop_cmp(cmp) // modifying the exit test of a counted loop messes the counted loop shape
1846       ) {
1847     const TypeInt* cmp1_in2 = phase->type(cmp1->in(2))->is_int();
1848     Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),phase->intcon(-cmp1_in2->_hi)));
1849     return new BoolNode( ncmp, _test._test );
1850   }
1851 
1852   // Change "bool eq/ne (cmp (phi (X -X) 0))" into "bool eq/ne (cmp X 0)"
1853   // since zero check of conditional negation of an integer is equal to
1854   // zero check of the integer directly.
1855   if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
1856       (cop == Op_CmpI) &&
1857       (cmp2_type == TypeInt::ZERO) &&
1858       (cmp1_op == Op_Phi)) {
1859     // There should be a diamond phi with true path at index 1 or 2
1860     PhiNode *phi = cmp1->as_Phi();
1861     int idx_true = phi->is_diamond_phi();
1862     if (idx_true != 0) {
1863       // True input is in(idx_true) while false input is in(3 - idx_true)
1864       Node *tin = phi->in(idx_true);
1865       Node *fin = phi->in(3 - idx_true);
1866       if ((tin->Opcode() == Op_SubI) &&
1867           (phase->type(tin->in(1)) == TypeInt::ZERO) &&
1868           (tin->in(2) == fin)) {
1869         // Found conditional negation at true path, create a new CmpINode without that
1870         Node *ncmp = phase->transform(new CmpINode(fin, cmp2));
1871         return new BoolNode(ncmp, _test._test);
1872       }
1873       if ((fin->Opcode() == Op_SubI) &&
1874           (phase->type(fin->in(1)) == TypeInt::ZERO) &&
1875           (fin->in(2) == tin)) {
1876         // Found conditional negation at false path, create a new CmpINode without that
1877         Node *ncmp = phase->transform(new CmpINode(tin, cmp2));
1878         return new BoolNode(ncmp, _test._test);
1879       }
1880     }
1881   }
1882 
1883   // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
1884   // most general case because negating 0x80000000 does nothing.  Needed for
1885   // the CmpF3/SubI/CmpI idiom.
1886   if( cop == Op_CmpI &&
1887       cmp1_op == Op_SubI &&
1888       cmp2_type == TypeInt::ZERO &&
1889       phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
1890       phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
1891     Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2));
1892     return new BoolNode( ncmp, _test.commute() );
1893   }
1894 
1895   // Try to optimize signed integer comparison
1896   return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type);
1897 
1898   //  The transformation below is not valid for either signed or unsigned
1899   //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
1900   //  This transformation can be resurrected when we are able to
1901   //  make inferences about the range of values being subtracted from
1902   //  (or added to) relative to the wraparound point.
1903   //
1904   //    // Remove +/-1's if possible.
1905   //    // "X <= Y-1" becomes "X <  Y"
1906   //    // "X+1 <= Y" becomes "X <  Y"
1907   //    // "X <  Y+1" becomes "X <= Y"
1908   //    // "X-1 <  Y" becomes "X <= Y"
1909   //    // Do not this to compares off of the counted-loop-end.  These guys are
1910   //    // checking the trip counter and they want to use the post-incremented
1911   //    // counter.  If they use the PRE-incremented counter, then the counter has
1912   //    // to be incremented in a private block on a loop backedge.
1913   //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
1914   //      return nullptr;
1915   //  #ifndef PRODUCT
1916   //    // Do not do this in a wash GVN pass during verification.
1917   //    // Gets triggered by too many simple optimizations to be bothered with
1918   //    // re-trying it again and again.
1919   //    if( !phase->allow_progress() ) return nullptr;
1920   //  #endif
1921   //    // Not valid for unsigned compare because of corner cases in involving zero.
1922   //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
1923   //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
1924   //    // "0 <=u Y" is always true).
1925   //    if( cmp->Opcode() == Op_CmpU ) return nullptr;
1926   //    int cmp2_op = cmp2->Opcode();
1927   //    if( _test._test == BoolTest::le ) {
1928   //      if( cmp1_op == Op_AddI &&
1929   //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
1930   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
1931   //      else if( cmp2_op == Op_AddI &&
1932   //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
1933   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
1934   //    } else if( _test._test == BoolTest::lt ) {
1935   //      if( cmp1_op == Op_AddI &&
1936   //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
1937   //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
1938   //      else if( cmp2_op == Op_AddI &&
1939   //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
1940   //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
1941   //    }
1942 }
1943 
1944 // We use the following Lemmas/insights for the following two transformations (1) and (2):
1945 //   x & y <=u y, for any x and y           (Lemma 1, masking always results in a smaller unsigned number)
1946 //   y <u y + 1 is always true if y != -1   (Lemma 2, (uint)(-1 + 1) == (uint)(UINT_MAX + 1) which overflows)
1947 //   y <u 0 is always false for any y       (Lemma 3, 0 == UINT_MIN and nothing can be smaller than that)
1948 //
1949 // (1a) Always:     Change ((x & m) <=u m  ) or ((m & x) <=u m  ) to always true   (true by Lemma 1)
1950 // (1b) If m != -1: Change ((x & m) <u  m + 1) or ((m & x) <u  m + 1) to always true:
1951 //    x & m <=u m          is always true   // (Lemma 1)
1952 //    x & m <=u m <u m + 1 is always true   // (Lemma 2: m <u m + 1, if m != -1)
1953 //
1954 // A counter example for (1b), if we allowed m == -1:
1955 //     (x & m)  <u m + 1
1956 //     (x & -1) <u 0
1957 //      x       <u 0
1958 //   which is false for any x (Lemma 3)
1959 //
1960 // (2) Change ((x & (m - 1)) <u m) or (((m - 1) & x) <u m) to (m >u 0)
1961 // This is the off-by-one variant of the above.
1962 //
1963 // We now prove that this replacement is correct. This is the same as proving
1964 //   "m >u 0" if and only if "x & (m - 1) <u m", i.e. "m >u 0 <=> x & (m - 1) <u m"
1965 //
1966 // We use (Lemma 1) and (Lemma 3) from above.
1967 //
1968 // Case "x & (m - 1) <u m => m >u 0":
1969 //   We prove this by contradiction:
1970 //     Assume m <=u 0 which is equivalent to m == 0:
1971 //   and thus
1972 //     x & (m - 1) <u m = 0               // m == 0
1973 //     y           <u     0               // y = x & (m - 1)
1974 //   by Lemma 3, this is always false, i.e. a contradiction to our assumption.
1975 //
1976 // Case "m >u 0 => x & (m - 1) <u m":
1977 //   x & (m - 1) <=u (m - 1)              // (Lemma 1)
1978 //   x & (m - 1) <=u (m - 1) <u m         // Using assumption m >u 0, no underflow of "m - 1"
1979 //
1980 //
1981 // Note that the signed version of "m > 0":
1982 //   m > 0 <=> x & (m - 1) <u m
1983 // does not hold:
1984 //   Assume m == -1 and x == -1:
1985 //     x  & (m - 1) <u m
1986 //     -1 & -2      <u -1
1987 //     -2           <u -1
1988 //     UINT_MAX - 1 <u UINT_MAX           // Signed to unsigned numbers
1989 // which is true while
1990 //   m > 0
1991 // is false which is a contradiction.
1992 //
1993 // (1a) and (1b) is covered by this method since we can directly return a true value as type while (2) is covered
1994 // in BoolNode::Ideal since we create a new non-constant node (see [CMPU_MASK]).
1995 const Type* BoolNode::Value_cmpu_and_mask(PhaseValues* phase) const {
1996   Node* cmp = in(1);
1997   if (cmp != nullptr && cmp->Opcode() == Op_CmpU) {
1998     Node* cmp1 = cmp->in(1);
1999     Node* cmp2 = cmp->in(2);
2000 
2001     if (cmp1->Opcode() == Op_AndI) {
2002       Node* m = nullptr;
2003       if (_test._test == BoolTest::le) {
2004         // (1a) "((x & m) <=u m)", cmp2 = m
2005         m = cmp2;
2006       } else if (_test._test == BoolTest::lt && cmp2->Opcode() == Op_AddI && cmp2->in(2)->find_int_con(0) == 1) {
2007         // (1b) "(x & m) <u m + 1" and "(m & x) <u m + 1", cmp2 = m + 1
2008         Node* rhs_m = cmp2->in(1);
2009         const TypeInt* rhs_m_type = phase->type(rhs_m)->isa_int();
2010         if (rhs_m_type != nullptr && (rhs_m_type->_lo > -1 || rhs_m_type->_hi < -1)) {
2011           // Exclude any case where m == -1 is possible.
2012           m = rhs_m;
2013         }
2014       }
2015 
2016       if (cmp1->in(2) == m || cmp1->in(1) == m) {
2017         return TypeInt::ONE;
2018       }
2019     }
2020   }
2021 
2022   return nullptr;
2023 }
2024 
2025 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
2026 // based on local information.   If the input is constant, do it.
2027 const Type* BoolNode::Value(PhaseGVN* phase) const {
2028   const Type* input_type = phase->type(in(1));
2029   if (input_type == Type::TOP) {
2030     return Type::TOP;
2031   }
2032   const Type* t = Value_cmpu_and_mask(phase);
2033   if (t != nullptr) {
2034     return t;
2035   }
2036 
2037   return _test.cc2logical(input_type);
2038 }
2039 
2040 #ifndef PRODUCT
2041 //------------------------------dump_spec--------------------------------------
2042 // Dump special per-node info
2043 void BoolNode::dump_spec(outputStream *st) const {
2044   st->print("[");
2045   _test.dump_on(st);
2046   st->print("]");
2047 }
2048 #endif
2049 
2050 //----------------------is_counted_loop_exit_test------------------------------
2051 // Returns true if node is used by a counted loop node.
2052 bool BoolNode::is_counted_loop_exit_test() {
2053   for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
2054     Node* use = fast_out(i);
2055     if (use->is_CountedLoopEnd()) {
2056       return true;
2057     }
2058   }
2059   return false;
2060 }
2061 
2062 //=============================================================================
2063 //------------------------------Value------------------------------------------
2064 const Type* AbsNode::Value(PhaseGVN* phase) const {
2065   const Type* t1 = phase->type(in(1));
2066   if (t1 == Type::TOP) return Type::TOP;
2067 
2068   switch (t1->base()) {
2069   case Type::Int: {
2070     const TypeInt* ti = t1->is_int();
2071     if (ti->is_con()) {
2072       return TypeInt::make(g_uabs(ti->get_con()));
2073     }
2074     break;
2075   }
2076   case Type::Long: {
2077     const TypeLong* tl = t1->is_long();
2078     if (tl->is_con()) {
2079       return TypeLong::make(g_uabs(tl->get_con()));
2080     }
2081     break;
2082   }
2083   case Type::FloatCon:
2084     return TypeF::make(abs(t1->getf()));
2085   case Type::DoubleCon:
2086     return TypeD::make(abs(t1->getd()));
2087   default:
2088     break;
2089   }
2090 
2091   return bottom_type();
2092 }
2093 
2094 //------------------------------Identity----------------------------------------
2095 Node* AbsNode::Identity(PhaseGVN* phase) {
2096   Node* in1 = in(1);
2097   // No need to do abs for non-negative values
2098   if (phase->type(in1)->higher_equal(TypeInt::POS) ||
2099       phase->type(in1)->higher_equal(TypeLong::POS)) {
2100     return in1;
2101   }
2102   // Convert "abs(abs(x))" into "abs(x)"
2103   if (in1->Opcode() == Opcode()) {
2104     return in1;
2105   }
2106   return this;
2107 }
2108 
2109 //------------------------------Ideal------------------------------------------
2110 Node* AbsNode::Ideal(PhaseGVN* phase, bool can_reshape) {
2111   Node* in1 = in(1);
2112   // Convert "abs(0-x)" into "abs(x)"
2113   if (in1->is_Sub() && phase->type(in1->in(1))->is_zero_type()) {
2114     set_req_X(1, in1->in(2), phase);
2115     return this;
2116   }
2117   return nullptr;
2118 }
2119 
2120 //=============================================================================
2121 //------------------------------Value------------------------------------------
2122 // Compute sqrt
2123 const Type* SqrtDNode::Value(PhaseGVN* phase) const {
2124   const Type *t1 = phase->type( in(1) );
2125   if( t1 == Type::TOP ) return Type::TOP;
2126   if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
2127   double d = t1->getd();
2128   if( d < 0.0 ) return Type::DOUBLE;
2129   return TypeD::make( sqrt( d ) );
2130 }
2131 
2132 const Type* SqrtFNode::Value(PhaseGVN* phase) const {
2133   const Type *t1 = phase->type( in(1) );
2134   if( t1 == Type::TOP ) return Type::TOP;
2135   if( t1->base() != Type::FloatCon ) return Type::FLOAT;
2136   float f = t1->getf();
2137   if( f < 0.0f ) return Type::FLOAT;
2138   return TypeF::make( (float)sqrt( (double)f ) );
2139 }
2140 
2141 const Type* SqrtHFNode::Value(PhaseGVN* phase) const {
2142   const Type* t1 = phase->type(in(1));
2143   if (t1 == Type::TOP) { return Type::TOP; }
2144   if (t1->base() != Type::HalfFloatCon) { return Type::HALF_FLOAT; }
2145   float f = t1->getf();
2146   if (f < 0.0f) return Type::HALF_FLOAT;
2147   return TypeH::make((float)sqrt((double)f));
2148 }
2149 
2150 static const Type* reverse_bytes(int opcode, const Type* con) {
2151   switch (opcode) {
2152     // It is valid in bytecode to load any int and pass it to a method that expects a smaller type (i.e., short, char).
2153     // Let's cast the value to match the Java behavior.
2154     case Op_ReverseBytesS:  return TypeInt::make(byteswap(static_cast<jshort>(con->is_int()->get_con())));
2155     case Op_ReverseBytesUS: return TypeInt::make(byteswap(static_cast<jchar>(con->is_int()->get_con())));
2156     case Op_ReverseBytesI:  return TypeInt::make(byteswap(con->is_int()->get_con()));
2157     case Op_ReverseBytesL:  return TypeLong::make(byteswap(con->is_long()->get_con()));
2158     default: ShouldNotReachHere();
2159   }
2160 }
2161 
2162 const Type* ReverseBytesNode::Value(PhaseGVN* phase) const {
2163   const Type* type = phase->type(in(1));
2164   if (type == Type::TOP) {
2165     return Type::TOP;
2166   }
2167   if (type->singleton()) {
2168     return reverse_bytes(Opcode(), type);
2169   }
2170   return bottom_type();
2171 }
2172 
2173 const Type* ReverseINode::Value(PhaseGVN* phase) const {
2174   const Type *t1 = phase->type( in(1) );
2175   if (t1 == Type::TOP) {
2176     return Type::TOP;
2177   }
2178   const TypeInt* t1int = t1->isa_int();
2179   if (t1int && t1int->is_con()) {
2180     jint res = reverse_bits(t1int->get_con());
2181     return TypeInt::make(res);
2182   }
2183   return bottom_type();
2184 }
2185 
2186 const Type* ReverseLNode::Value(PhaseGVN* phase) const {
2187   const Type *t1 = phase->type( in(1) );
2188   if (t1 == Type::TOP) {
2189     return Type::TOP;
2190   }
2191   const TypeLong* t1long = t1->isa_long();
2192   if (t1long && t1long->is_con()) {
2193     jlong res = reverse_bits(t1long->get_con());
2194     return TypeLong::make(res);
2195   }
2196   return bottom_type();
2197 }
2198 
2199 Node* ReverseINode::Identity(PhaseGVN* phase) {
2200   if (in(1)->Opcode() == Op_ReverseI) {
2201     return in(1)->in(1);
2202   }
2203   return this;
2204 }
2205 
2206 Node* ReverseLNode::Identity(PhaseGVN* phase) {
2207   if (in(1)->Opcode() == Op_ReverseL) {
2208     return in(1)->in(1);
2209   }
2210   return this;
2211 }
--- EOF ---