1 /*
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   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).
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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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  24 
  25 #include "memory/allocation.inline.hpp"
  26 #include "opto/addnode.hpp"
  27 #include "opto/castnode.hpp"
  28 #include "opto/cfgnode.hpp"
  29 #include "opto/connode.hpp"
  30 #include "opto/machnode.hpp"
  31 #include "opto/movenode.hpp"
  32 #include "opto/mulnode.hpp"
  33 #include "opto/phaseX.hpp"
  34 #include "opto/subnode.hpp"
  35 
  36 // Portions of code courtesy of Clifford Click
  37 
  38 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  39 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  40 // all inherited from this class.  The various identity values are supplied
  41 // by virtual functions.
  42 
  43 
  44 //=============================================================================
  45 //------------------------------hash-------------------------------------------
  46 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  47 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  48 // the same value in the presence of edge swapping.
  49 uint AddNode::hash() const {
  50   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  51 }
  52 
  53 //------------------------------Identity---------------------------------------
  54 // If either input is a constant 0, return the other input.
  55 Node* AddNode::Identity(PhaseGVN* phase) {
  56   const Type *zero = add_id();  // The additive identity
  57   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  58   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  59   return this;
  60 }
  61 
  62 //------------------------------commute----------------------------------------
  63 // Commute operands to move loads and constants to the right.
  64 static bool commute(PhaseGVN* phase, Node* add) {
  65   Node *in1 = add->in(1);
  66   Node *in2 = add->in(2);
  67 
  68   // convert "max(a,b) + min(a,b)" into "a+b".
  69   if ((in1->Opcode() == add->as_Add()->max_opcode() && in2->Opcode() == add->as_Add()->min_opcode())
  70       || (in1->Opcode() == add->as_Add()->min_opcode() && in2->Opcode() == add->as_Add()->max_opcode())) {
  71     Node *in11 = in1->in(1);
  72     Node *in12 = in1->in(2);
  73 
  74     Node *in21 = in2->in(1);
  75     Node *in22 = in2->in(2);
  76 
  77     if ((in11 == in21 && in12 == in22) ||
  78         (in11 == in22 && in12 == in21)) {
  79       add->set_req_X(1, in11, phase);
  80       add->set_req_X(2, in12, phase);
  81       return true;
  82     }
  83   }
  84 
  85   bool con_left = phase->type(in1)->singleton();
  86   bool con_right = phase->type(in2)->singleton();
  87 
  88   // Convert "1+x" into "x+1".
  89   // Right is a constant; leave it
  90   if( con_right ) return false;
  91   // Left is a constant; move it right.
  92   if( con_left ) {
  93     add->swap_edges(1, 2);
  94     return true;
  95   }
  96 
  97   // Convert "Load+x" into "x+Load".
  98   // Now check for loads
  99   if (in2->is_Load()) {
 100     if (!in1->is_Load()) {
 101       // already x+Load to return
 102       return false;
 103     }
 104     // both are loads, so fall through to sort inputs by idx
 105   } else if( in1->is_Load() ) {
 106     // Left is a Load and Right is not; move it right.
 107     add->swap_edges(1, 2);
 108     return true;
 109   }
 110 
 111   PhiNode *phi;
 112   // Check for tight loop increments: Loop-phi of Add of loop-phi
 113   if (in1->is_Phi() && (phi = in1->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add)
 114     return false;
 115   if (in2->is_Phi() && (phi = in2->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add) {
 116     add->swap_edges(1, 2);
 117     return true;
 118   }
 119 
 120   // Otherwise, sort inputs (commutativity) to help value numbering.
 121   if( in1->_idx > in2->_idx ) {
 122     add->swap_edges(1, 2);
 123     return true;
 124   }
 125   return false;
 126 }
 127 
 128 //------------------------------Idealize---------------------------------------
 129 // If we get here, we assume we are associative!
 130 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 131   const Type *t1 = phase->type(in(1));
 132   const Type *t2 = phase->type(in(2));
 133   bool con_left  = t1->singleton();
 134   bool con_right = t2->singleton();
 135 
 136   // Check for commutative operation desired
 137   if (commute(phase, this)) return this;
 138 
 139   AddNode *progress = nullptr;             // Progress flag
 140 
 141   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 142   // constant, and the left input is an add of a constant, flatten the
 143   // expression tree.
 144   Node *add1 = in(1);
 145   Node *add2 = in(2);
 146   int add1_op = add1->Opcode();
 147   int this_op = Opcode();
 148   if (con_right && t2 != Type::TOP && // Right input is a constant?
 149       add1_op == this_op) { // Left input is an Add?
 150 
 151     // Type of left _in right input
 152     const Type *t12 = phase->type(add1->in(2));
 153     if (t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
 154       // Check for rare case of closed data cycle which can happen inside
 155       // unreachable loops. In these cases the computation is undefined.
 156 #ifdef ASSERT
 157       Node *add11    = add1->in(1);
 158       int   add11_op = add11->Opcode();
 159       if ((add1 == add1->in(1))
 160           || (add11_op == this_op && add11->in(1) == add1)) {
 161         assert(false, "dead loop in AddNode::Ideal");
 162       }
 163 #endif
 164       // The Add of the flattened expression
 165       Node *x1 = add1->in(1);
 166       Node *x2 = phase->makecon(add1->as_Add()->add_ring(t2, t12));
 167       set_req_X(2, x2, phase);
 168       set_req_X(1, x1, phase);
 169       progress = this;            // Made progress
 170       add1 = in(1);
 171       add1_op = add1->Opcode();
 172     }
 173   }
 174 
 175   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 176   if (add1_op == this_op && !con_right) {
 177     Node *a12 = add1->in(2);
 178     const Type *t12 = phase->type( a12 );
 179     if (t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 180         !(add1->in(1)->is_Phi() && (add1->in(1)->as_Phi()->is_tripcount(T_INT) || add1->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 181       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 182       add2 = add1->clone();
 183       add2->set_req(2, in(2));
 184       add2 = phase->transform(add2);
 185       set_req_X(1, add2, phase);
 186       set_req_X(2, a12, phase);
 187       progress = this;
 188       add2 = a12;
 189     }
 190   }
 191 
 192   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 193   int add2_op = add2->Opcode();
 194   if (add2_op == this_op && !con_left) {
 195     Node *a22 = add2->in(2);
 196     const Type *t22 = phase->type( a22 );
 197     if (t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 198         !(add2->in(1)->is_Phi() && (add2->in(1)->as_Phi()->is_tripcount(T_INT) || add2->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 199       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 200       Node *addx = add2->clone();
 201       addx->set_req(1, in(1));
 202       addx->set_req(2, add2->in(1));
 203       addx = phase->transform(addx);
 204       set_req_X(1, addx, phase);
 205       set_req_X(2, a22, phase);
 206       progress = this;
 207     }
 208   }
 209 
 210   return progress;
 211 }
 212 
 213 //------------------------------Value-----------------------------------------
 214 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 215 // the other input's symbols.
 216 const Type* AddNode::Value(PhaseGVN* phase) const {
 217   // Either input is TOP ==> the result is TOP
 218   const Type* t1 = phase->type(in(1));
 219   const Type* t2 = phase->type(in(2));
 220   if (t1 == Type::TOP || t2 == Type::TOP) {
 221     return Type::TOP;
 222   }
 223 
 224   // Check for an addition involving the additive identity
 225   const Type* tadd = add_of_identity(t1, t2);
 226   if (tadd != nullptr) {
 227     return tadd;
 228   }
 229 
 230   return add_ring(t1, t2);               // Local flavor of type addition
 231 }
 232 
 233 //------------------------------add_identity-----------------------------------
 234 // Check for addition of the identity
 235 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 236   const Type *zero = add_id();  // The additive identity
 237   if( t1->higher_equal( zero ) ) return t2;
 238   if( t2->higher_equal( zero ) ) return t1;
 239 
 240   return nullptr;
 241 }
 242 
 243 AddNode* AddNode::make(Node* in1, Node* in2, BasicType bt) {
 244   switch (bt) {
 245     case T_INT:
 246       return new AddINode(in1, in2);
 247     case T_LONG:
 248       return new AddLNode(in1, in2);
 249     default:
 250       fatal("Not implemented for %s", type2name(bt));
 251   }
 252   return nullptr;
 253 }
 254 
 255 bool AddNode::is_not(PhaseGVN* phase, Node* n, BasicType bt) {
 256   return n->Opcode() == Op_Xor(bt) && phase->type(n->in(2)) == TypeInteger::minus_1(bt);
 257 }
 258 
 259 AddNode* AddNode::make_not(PhaseGVN* phase, Node* n, BasicType bt) {
 260   switch (bt) {
 261     case T_INT:
 262       return new XorINode(n, phase->intcon(-1));
 263     case T_LONG:
 264       return new XorLNode(n, phase->longcon(-1L));
 265     default:
 266       fatal("Not implemented for %s", type2name(bt));
 267   }
 268   return nullptr;
 269 }
 270 
 271 //=============================================================================
 272 //------------------------------Idealize---------------------------------------
 273 Node* AddNode::IdealIL(PhaseGVN* phase, bool can_reshape, BasicType bt) {
 274   Node* in1 = in(1);
 275   Node* in2 = in(2);
 276   int op1 = in1->Opcode();
 277   int op2 = in2->Opcode();
 278   // Fold (con1-x)+con2 into (con1+con2)-x
 279   if (op1 == Op_Add(bt) && op2 == Op_Sub(bt)) {
 280     // Swap edges to try optimizations below
 281     in1 = in2;
 282     in2 = in(1);
 283     op1 = op2;
 284     op2 = in2->Opcode();
 285   }
 286   if (op1 == Op_Sub(bt)) {
 287     const Type* t_sub1 = phase->type(in1->in(1));
 288     const Type* t_2    = phase->type(in2       );
 289     if (t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP) {
 290       return SubNode::make(phase->makecon(add_ring(t_sub1, t_2)), in1->in(2), bt);
 291     }
 292     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 293     if (op2 == Op_Sub(bt)) {
 294       // Check for dead cycle: d = (a-b)+(c-d)
 295       assert( in1->in(2) != this && in2->in(2) != this,
 296               "dead loop in AddINode::Ideal" );
 297       Node* sub = SubNode::make(nullptr, nullptr, bt);
 298       Node* sub_in1;
 299       PhaseIterGVN* igvn = phase->is_IterGVN();
 300       // During IGVN, if both inputs of the new AddNode are a tree of SubNodes, this same transformation will be applied
 301       // to every node of the tree. Calling transform() causes the transformation to be applied recursively, once per
 302       // tree node whether some subtrees are identical or not. Pushing to the IGVN worklist instead, causes the transform
 303       // to be applied once per unique subtrees (because all uses of a subtree are updated with the result of the
 304       // transformation). In case of a large tree, this can make a difference in compilation time.
 305       if (igvn != nullptr) {
 306         sub_in1 = igvn->register_new_node_with_optimizer(AddNode::make(in1->in(1), in2->in(1), bt));
 307       } else {
 308         sub_in1 = phase->transform(AddNode::make(in1->in(1), in2->in(1), bt));
 309       }
 310       Node* sub_in2;
 311       if (igvn != nullptr) {
 312         sub_in2 = igvn->register_new_node_with_optimizer(AddNode::make(in1->in(2), in2->in(2), bt));
 313       } else {
 314         sub_in2 = phase->transform(AddNode::make(in1->in(2), in2->in(2), bt));
 315       }
 316       sub->init_req(1, sub_in1);
 317       sub->init_req(2, sub_in2);
 318       return sub;
 319     }
 320     // Convert "(a-b)+(b+c)" into "(a+c)"
 321     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(1)) {
 322       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 323       return AddNode::make(in1->in(1), in2->in(2), bt);
 324     }
 325     // Convert "(a-b)+(c+b)" into "(a+c)"
 326     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(2)) {
 327       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 328       return AddNode::make(in1->in(1), in2->in(1), bt);
 329     }
 330   }
 331 
 332   // Convert (con - y) + x into "(x - y) + con"
 333   if (op1 == Op_Sub(bt) && in1->in(1)->Opcode() == Op_ConIL(bt)
 334       && in1 != in1->in(2) && !(in1->in(2)->is_Phi() && in1->in(2)->as_Phi()->is_tripcount(bt))) {
 335     return AddNode::make(phase->transform(SubNode::make(in2, in1->in(2), bt)), in1->in(1), bt);
 336   }
 337 
 338   // Convert x + (con - y) into "(x - y) + con"
 339   if (op2 == Op_Sub(bt) && in2->in(1)->Opcode() == Op_ConIL(bt)
 340       && in2 != in2->in(2) && !(in2->in(2)->is_Phi() && in2->in(2)->as_Phi()->is_tripcount(bt))) {
 341     return AddNode::make(phase->transform(SubNode::make(in1, in2->in(2), bt)), in2->in(1), bt);
 342   }
 343 
 344   // Associative
 345   if (op1 == Op_Mul(bt) && op2 == Op_Mul(bt)) {
 346     Node* add_in1 = nullptr;
 347     Node* add_in2 = nullptr;
 348     Node* mul_in = nullptr;
 349 
 350     if (in1->in(1) == in2->in(1)) {
 351       // Convert "a*b+a*c into a*(b+c)
 352       add_in1 = in1->in(2);
 353       add_in2 = in2->in(2);
 354       mul_in = in1->in(1);
 355     } else if (in1->in(2) == in2->in(1)) {
 356       // Convert a*b+b*c into b*(a+c)
 357       add_in1 = in1->in(1);
 358       add_in2 = in2->in(2);
 359       mul_in = in1->in(2);
 360     } else if (in1->in(2) == in2->in(2)) {
 361       // Convert a*c+b*c into (a+b)*c
 362       add_in1 = in1->in(1);
 363       add_in2 = in2->in(1);
 364       mul_in = in1->in(2);
 365     } else if (in1->in(1) == in2->in(2)) {
 366       // Convert a*b+c*a into a*(b+c)
 367       add_in1 = in1->in(2);
 368       add_in2 = in2->in(1);
 369       mul_in = in1->in(1);
 370     }
 371 
 372     if (mul_in != nullptr) {
 373       Node* add = phase->transform(AddNode::make(add_in1, add_in2, bt));
 374       return MulNode::make(mul_in, add, bt);
 375     }
 376   }
 377 
 378   // Convert (x >>> rshift) + (x << lshift) into RotateRight(x, rshift)
 379   if (Matcher::match_rule_supported(Op_RotateRight) &&
 380       ((op1 == Op_URShift(bt) && op2 == Op_LShift(bt)) || (op1 == Op_LShift(bt) && op2 == Op_URShift(bt))) &&
 381       in1->in(1) != nullptr && in1->in(1) == in2->in(1)) {
 382     Node* rshift = op1 == Op_URShift(bt) ? in1->in(2) : in2->in(2);
 383     Node* lshift = op1 == Op_URShift(bt) ? in2->in(2) : in1->in(2);
 384     if (rshift != nullptr && lshift != nullptr) {
 385       const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 386       const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 387       int bits = bt == T_INT ? 32 : 64;
 388       int mask = bt == T_INT ? 0x1F : 0x3F;
 389       if (lshift_t != nullptr && lshift_t->is_con() &&
 390           rshift_t != nullptr && rshift_t->is_con() &&
 391           ((lshift_t->get_con() & mask) == (bits - (rshift_t->get_con() & mask)))) {
 392         return new RotateRightNode(in1->in(1), phase->intcon(rshift_t->get_con() & mask), TypeInteger::bottom(bt));
 393       }
 394     }
 395   }
 396 
 397   return AddNode::Ideal(phase, can_reshape);
 398 }
 399 
 400 
 401 Node* AddINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 402   Node* in1 = in(1);
 403   Node* in2 = in(2);
 404   int op1 = in1->Opcode();
 405   int op2 = in2->Opcode();
 406 
 407   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 408   // Helps with array allocation math constant folding
 409   // See 4790063:
 410   // Unrestricted transformation is unsafe for some runtime values of 'x'
 411   // ( x ==  0, z == 1, y == -1 ) fails
 412   // ( x == -5, z == 1, y ==  1 ) fails
 413   // Transform works for small z and small negative y when the addition
 414   // (x + (y << z)) does not cross zero.
 415   // Implement support for negative y and (x >= -(y << z))
 416   // Have not observed cases where type information exists to support
 417   // positive y and (x <= -(y << z))
 418   if (op1 == Op_URShiftI && op2 == Op_ConI &&
 419       in1->in(2)->Opcode() == Op_ConI) {
 420     jint z = phase->type(in1->in(2))->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 421     jint y = phase->type(in2)->is_int()->get_con();
 422 
 423     if (z < 5 && -5 < y && y < 0) {
 424       const Type* t_in11 = phase->type(in1->in(1));
 425       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z))) {
 426         Node* a = phase->transform(new AddINode( in1->in(1), phase->intcon(y<<z)));
 427         return new URShiftINode(a, in1->in(2));
 428       }
 429     }
 430   }
 431 
 432   return AddNode::IdealIL(phase, can_reshape, T_INT);
 433 }
 434 
 435 
 436 //------------------------------Identity---------------------------------------
 437 // Fold (x-y)+y  OR  y+(x-y)  into  x
 438 Node* AddINode::Identity(PhaseGVN* phase) {
 439   if (in(1)->Opcode() == Op_SubI && in(1)->in(2) == in(2)) {
 440     return in(1)->in(1);
 441   } else if (in(2)->Opcode() == Op_SubI && in(2)->in(2) == in(1)) {
 442     return in(2)->in(1);
 443   }
 444   return AddNode::Identity(phase);
 445 }
 446 
 447 
 448 //------------------------------add_ring---------------------------------------
 449 // Supplied function returns the sum of the inputs.  Guaranteed never
 450 // to be passed a TOP or BOTTOM type, these are filtered out by
 451 // pre-check.
 452 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 453   const TypeInt *r0 = t0->is_int(); // Handy access
 454   const TypeInt *r1 = t1->is_int();
 455   int lo = java_add(r0->_lo, r1->_lo);
 456   int hi = java_add(r0->_hi, r1->_hi);
 457   if( !(r0->is_con() && r1->is_con()) ) {
 458     // Not both constants, compute approximate result
 459     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 460       lo = min_jint; hi = max_jint; // Underflow on the low side
 461     }
 462     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 463       lo = min_jint; hi = max_jint; // Overflow on the high side
 464     }
 465     if( lo > hi ) {               // Handle overflow
 466       lo = min_jint; hi = max_jint;
 467     }
 468   } else {
 469     // both constants, compute precise result using 'lo' and 'hi'
 470     // Semantics define overflow and underflow for integer addition
 471     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 472   }
 473   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 474 }
 475 
 476 
 477 //=============================================================================
 478 //------------------------------Idealize---------------------------------------
 479 Node* AddLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 480   return AddNode::IdealIL(phase, can_reshape, T_LONG);
 481 }
 482 
 483 
 484 //------------------------------Identity---------------------------------------
 485 // Fold (x-y)+y  OR  y+(x-y)  into  x
 486 Node* AddLNode::Identity(PhaseGVN* phase) {
 487   if (in(1)->Opcode() == Op_SubL && in(1)->in(2) == in(2)) {
 488     return in(1)->in(1);
 489   } else if (in(2)->Opcode() == Op_SubL && in(2)->in(2) == in(1)) {
 490     return in(2)->in(1);
 491   }
 492   return AddNode::Identity(phase);
 493 }
 494 
 495 
 496 //------------------------------add_ring---------------------------------------
 497 // Supplied function returns the sum of the inputs.  Guaranteed never
 498 // to be passed a TOP or BOTTOM type, these are filtered out by
 499 // pre-check.
 500 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 501   const TypeLong *r0 = t0->is_long(); // Handy access
 502   const TypeLong *r1 = t1->is_long();
 503   jlong lo = java_add(r0->_lo, r1->_lo);
 504   jlong hi = java_add(r0->_hi, r1->_hi);
 505   if( !(r0->is_con() && r1->is_con()) ) {
 506     // Not both constants, compute approximate result
 507     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 508       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 509     }
 510     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 511       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 512     }
 513     if( lo > hi ) {               // Handle overflow
 514       lo = min_jlong; hi = max_jlong;
 515     }
 516   } else {
 517     // both constants, compute precise result using 'lo' and 'hi'
 518     // Semantics define overflow and underflow for integer addition
 519     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 520   }
 521   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 522 }
 523 
 524 
 525 //=============================================================================
 526 //------------------------------add_of_identity--------------------------------
 527 // Check for addition of the identity
 528 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 529   // x ADD 0  should return x unless 'x' is a -zero
 530   //
 531   // const Type *zero = add_id();     // The additive identity
 532   // jfloat f1 = t1->getf();
 533   // jfloat f2 = t2->getf();
 534   //
 535   // if( t1->higher_equal( zero ) ) return t2;
 536   // if( t2->higher_equal( zero ) ) return t1;
 537 
 538   return nullptr;
 539 }
 540 
 541 //------------------------------add_ring---------------------------------------
 542 // Supplied function returns the sum of the inputs.
 543 // This also type-checks the inputs for sanity.  Guaranteed never to
 544 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 545 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 546   if (!t0->isa_float_constant() || !t1->isa_float_constant()) {
 547     return bottom_type();
 548   }
 549   return TypeF::make( t0->getf() + t1->getf() );
 550 }
 551 
 552 //------------------------------Ideal------------------------------------------
 553 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 554   // Floating point additions are not associative because of boundary conditions (infinity)
 555   return commute(phase, this) ? this : nullptr;
 556 }
 557 
 558 
 559 //=============================================================================
 560 //------------------------------add_of_identity--------------------------------
 561 // Check for addition of the identity
 562 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 563   // x ADD 0  should return x unless 'x' is a -zero
 564   //
 565   // const Type *zero = add_id();     // The additive identity
 566   // jfloat f1 = t1->getf();
 567   // jfloat f2 = t2->getf();
 568   //
 569   // if( t1->higher_equal( zero ) ) return t2;
 570   // if( t2->higher_equal( zero ) ) return t1;
 571 
 572   return nullptr;
 573 }
 574 //------------------------------add_ring---------------------------------------
 575 // Supplied function returns the sum of the inputs.
 576 // This also type-checks the inputs for sanity.  Guaranteed never to
 577 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 578 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 579   if (!t0->isa_double_constant() || !t1->isa_double_constant()) {
 580     return bottom_type();
 581   }
 582   return TypeD::make( t0->getd() + t1->getd() );
 583 }
 584 
 585 //------------------------------Ideal------------------------------------------
 586 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 587   // Floating point additions are not associative because of boundary conditions (infinity)
 588   return commute(phase, this) ? this : nullptr;
 589 }
 590 
 591 
 592 //=============================================================================
 593 //------------------------------Identity---------------------------------------
 594 // If one input is a constant 0, return the other input.
 595 Node* AddPNode::Identity(PhaseGVN* phase) {
 596   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 597 }
 598 
 599 //------------------------------Idealize---------------------------------------
 600 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 601   // Bail out if dead inputs
 602   if( phase->type( in(Address) ) == Type::TOP ) return nullptr;
 603 
 604   // If the left input is an add of a constant, flatten the expression tree.
 605   const Node *n = in(Address);
 606   if (n->is_AddP() && n->in(Base) == in(Base)) {
 607     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 608     assert( !addp->in(Address)->is_AddP() ||
 609              addp->in(Address)->as_AddP() != addp,
 610             "dead loop in AddPNode::Ideal" );
 611     // Type of left input's right input
 612     const Type *t = phase->type( addp->in(Offset) );
 613     if( t == Type::TOP ) return nullptr;
 614     const TypeX *t12 = t->is_intptr_t();
 615     if( t12->is_con() ) {       // Left input is an add of a constant?
 616       // If the right input is a constant, combine constants
 617       const Type *temp_t2 = phase->type( in(Offset) );
 618       if( temp_t2 == Type::TOP ) return nullptr;
 619       const TypeX *t2 = temp_t2->is_intptr_t();
 620       Node* address;
 621       Node* offset;
 622       if( t2->is_con() ) {
 623         // The Add of the flattened expression
 624         address = addp->in(Address);
 625         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 626       } else {
 627         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 628         address = phase->transform(new AddPNode(in(Base),addp->in(Address),in(Offset)));
 629         offset  = addp->in(Offset);
 630       }
 631       set_req_X(Address, address, phase);
 632       set_req_X(Offset, offset, phase);
 633       return this;
 634     }
 635   }
 636 
 637   // Raw pointers?
 638   if( in(Base)->bottom_type() == Type::TOP ) {
 639     // If this is a null+long form (from unsafe accesses), switch to a rawptr.
 640     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
 641       Node* offset = in(Offset);
 642       return new CastX2PNode(offset);
 643     }
 644   }
 645 
 646   // If the right is an add of a constant, push the offset down.
 647   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
 648   // The idea is to merge array_base+scaled_index groups together,
 649   // and only have different constant offsets from the same base.
 650   const Node *add = in(Offset);
 651   if( add->Opcode() == Op_AddX && add->in(1) != add ) {
 652     const Type *t22 = phase->type( add->in(2) );
 653     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?
 654       set_req(Address, phase->transform(new AddPNode(in(Base),in(Address),add->in(1))));
 655       set_req_X(Offset, add->in(2), phase); // puts add on igvn worklist if needed
 656       return this;              // Made progress
 657     }
 658   }
 659 
 660   return nullptr;                  // No progress
 661 }
 662 
 663 //------------------------------bottom_type------------------------------------
 664 // Bottom-type is the pointer-type with unknown offset.
 665 const Type *AddPNode::bottom_type() const {
 666   if (in(Address) == nullptr)  return TypePtr::BOTTOM;
 667   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
 668   if( !tp ) return Type::TOP;   // TOP input means TOP output
 669   assert( in(Offset)->Opcode() != Op_ConP, "" );
 670   const Type *t = in(Offset)->bottom_type();
 671   if( t == Type::TOP )
 672     return tp->add_offset(Type::OffsetTop);
 673   const TypeX *tx = t->is_intptr_t();
 674   intptr_t txoffset = Type::OffsetBot;
 675   if (tx->is_con()) {   // Left input is an add of a constant?
 676     txoffset = tx->get_con();
 677   }
 678   return tp->add_offset(txoffset);
 679 }
 680 
 681 //------------------------------Value------------------------------------------
 682 const Type* AddPNode::Value(PhaseGVN* phase) const {
 683   // Either input is TOP ==> the result is TOP
 684   const Type *t1 = phase->type( in(Address) );
 685   const Type *t2 = phase->type( in(Offset) );
 686   if( t1 == Type::TOP ) return Type::TOP;
 687   if( t2 == Type::TOP ) return Type::TOP;
 688 
 689   // Left input is a pointer
 690   const TypePtr *p1 = t1->isa_ptr();
 691   // Right input is an int
 692   const TypeX *p2 = t2->is_intptr_t();
 693   // Add 'em
 694   intptr_t p2offset = Type::OffsetBot;
 695   if (p2->is_con()) {   // Left input is an add of a constant?
 696     p2offset = p2->get_con();
 697   }
 698   return p1->add_offset(p2offset);
 699 }
 700 
 701 //------------------------Ideal_base_and_offset--------------------------------
 702 // Split an oop pointer into a base and offset.
 703 // (The offset might be Type::OffsetBot in the case of an array.)
 704 // Return the base, or null if failure.
 705 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseValues* phase,
 706                                       // second return value:
 707                                       intptr_t& offset) {
 708   if (ptr->is_AddP()) {
 709     Node* base = ptr->in(AddPNode::Base);
 710     Node* addr = ptr->in(AddPNode::Address);
 711     Node* offs = ptr->in(AddPNode::Offset);
 712     if (base == addr || base->is_top()) {
 713       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 714       if (offset != Type::OffsetBot) {
 715         return addr;
 716       }
 717     }
 718   }
 719   offset = Type::OffsetBot;
 720   return nullptr;
 721 }
 722 
 723 //------------------------------unpack_offsets----------------------------------
 724 // Collect the AddP offset values into the elements array, giving up
 725 // if there are more than length.
 726 int AddPNode::unpack_offsets(Node* elements[], int length) const {
 727   int count = 0;
 728   Node const* addr = this;
 729   Node* base = addr->in(AddPNode::Base);
 730   while (addr->is_AddP()) {
 731     if (addr->in(AddPNode::Base) != base) {
 732       // give up
 733       return -1;
 734     }
 735     elements[count++] = addr->in(AddPNode::Offset);
 736     if (count == length) {
 737       // give up
 738       return -1;
 739     }
 740     addr = addr->in(AddPNode::Address);
 741   }
 742   if (addr != base) {
 743     return -1;
 744   }
 745   return count;
 746 }
 747 
 748 //------------------------------match_edge-------------------------------------
 749 // Do we Match on this edge index or not?  Do not match base pointer edge
 750 uint AddPNode::match_edge(uint idx) const {
 751   return idx > Base;
 752 }
 753 
 754 //=============================================================================
 755 //------------------------------Identity---------------------------------------
 756 Node* OrINode::Identity(PhaseGVN* phase) {
 757   // x | x => x
 758   if (in(1) == in(2)) {
 759     return in(1);
 760   }
 761 
 762   return AddNode::Identity(phase);
 763 }
 764 
 765 // Find shift value for Integer or Long OR.
 766 static Node* rotate_shift(PhaseGVN* phase, Node* lshift, Node* rshift, int mask) {
 767   // val << norm_con_shift | val >> ({32|64} - norm_con_shift) => rotate_left val, norm_con_shift
 768   const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 769   const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 770   if (lshift_t != nullptr && lshift_t->is_con() &&
 771       rshift_t != nullptr && rshift_t->is_con() &&
 772       ((lshift_t->get_con() & mask) == ((mask + 1) - (rshift_t->get_con() & mask)))) {
 773     return phase->intcon(lshift_t->get_con() & mask);
 774   }
 775   // val << var_shift | val >> ({0|32|64} - var_shift) => rotate_left val, var_shift
 776   if (rshift->Opcode() == Op_SubI && rshift->in(2) == lshift && rshift->in(1)->is_Con()){
 777     const TypeInt* shift_t = phase->type(rshift->in(1))->isa_int();
 778     if (shift_t != nullptr && shift_t->is_con() &&
 779         (shift_t->get_con() == 0 || shift_t->get_con() == (mask + 1))) {
 780       return lshift;
 781     }
 782   }
 783   return nullptr;
 784 }
 785 
 786 Node* OrINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 787   int lopcode = in(1)->Opcode();
 788   int ropcode = in(2)->Opcode();
 789   if (Matcher::match_rule_supported(Op_RotateLeft) &&
 790       lopcode == Op_LShiftI && ropcode == Op_URShiftI && in(1)->in(1) == in(2)->in(1)) {
 791     Node* lshift = in(1)->in(2);
 792     Node* rshift = in(2)->in(2);
 793     Node* shift = rotate_shift(phase, lshift, rshift, 0x1F);
 794     if (shift != nullptr) {
 795       return new RotateLeftNode(in(1)->in(1), shift, TypeInt::INT);
 796     }
 797     return nullptr;
 798   }
 799   if (Matcher::match_rule_supported(Op_RotateRight) &&
 800       lopcode == Op_URShiftI && ropcode == Op_LShiftI && in(1)->in(1) == in(2)->in(1)) {
 801     Node* rshift = in(1)->in(2);
 802     Node* lshift = in(2)->in(2);
 803     Node* shift = rotate_shift(phase, rshift, lshift, 0x1F);
 804     if (shift != nullptr) {
 805       return new RotateRightNode(in(1)->in(1), shift, TypeInt::INT);
 806     }
 807   }
 808 
 809   // Convert "~a | ~b" into "~(a & b)"
 810   if (AddNode::is_not(phase, in(1), T_INT) && AddNode::is_not(phase, in(2), T_INT)) {
 811     Node* and_a_b = new AndINode(in(1)->in(1), in(2)->in(1));
 812     Node* tn = phase->transform(and_a_b);
 813     return AddNode::make_not(phase, tn, T_INT);
 814   }
 815   return nullptr;
 816 }
 817 
 818 //------------------------------add_ring---------------------------------------
 819 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 820 // the logical operations the ring's ADD is really a logical OR function.
 821 // This also type-checks the inputs for sanity.  Guaranteed never to
 822 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 823 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
 824   const TypeInt *r0 = t0->is_int(); // Handy access
 825   const TypeInt *r1 = t1->is_int();
 826 
 827   // If both args are bool, can figure out better types
 828   if ( r0 == TypeInt::BOOL ) {
 829     if ( r1 == TypeInt::ONE) {
 830       return TypeInt::ONE;
 831     } else if ( r1 == TypeInt::BOOL ) {
 832       return TypeInt::BOOL;
 833     }
 834   } else if ( r0 == TypeInt::ONE ) {
 835     if ( r1 == TypeInt::BOOL ) {
 836       return TypeInt::ONE;
 837     }
 838   }
 839 
 840   // If either input is not a constant, just return all integers.
 841   if( !r0->is_con() || !r1->is_con() )
 842     return TypeInt::INT;        // Any integer, but still no symbols.
 843 
 844   // Otherwise just OR them bits.
 845   return TypeInt::make( r0->get_con() | r1->get_con() );
 846 }
 847 
 848 //=============================================================================
 849 //------------------------------Identity---------------------------------------
 850 Node* OrLNode::Identity(PhaseGVN* phase) {
 851   // x | x => x
 852   if (in(1) == in(2)) {
 853     return in(1);
 854   }
 855 
 856   return AddNode::Identity(phase);
 857 }
 858 
 859 Node* OrLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 860   int lopcode = in(1)->Opcode();
 861   int ropcode = in(2)->Opcode();
 862   if (Matcher::match_rule_supported(Op_RotateLeft) &&
 863       lopcode == Op_LShiftL && ropcode == Op_URShiftL && in(1)->in(1) == in(2)->in(1)) {
 864     Node* lshift = in(1)->in(2);
 865     Node* rshift = in(2)->in(2);
 866     Node* shift = rotate_shift(phase, lshift, rshift, 0x3F);
 867     if (shift != nullptr) {
 868       return new RotateLeftNode(in(1)->in(1), shift, TypeLong::LONG);
 869     }
 870     return nullptr;
 871   }
 872   if (Matcher::match_rule_supported(Op_RotateRight) &&
 873       lopcode == Op_URShiftL && ropcode == Op_LShiftL && in(1)->in(1) == in(2)->in(1)) {
 874     Node* rshift = in(1)->in(2);
 875     Node* lshift = in(2)->in(2);
 876     Node* shift = rotate_shift(phase, rshift, lshift, 0x3F);
 877     if (shift != nullptr) {
 878       return new RotateRightNode(in(1)->in(1), shift, TypeLong::LONG);
 879     }
 880   }
 881 
 882   // Convert "~a | ~b" into "~(a & b)"
 883   if (AddNode::is_not(phase, in(1), T_LONG) && AddNode::is_not(phase, in(2), T_LONG)) {
 884     Node* and_a_b = new AndLNode(in(1)->in(1), in(2)->in(1));
 885     Node* tn = phase->transform(and_a_b);
 886     return AddNode::make_not(phase, tn, T_LONG);
 887   }
 888 
 889   return nullptr;
 890 }
 891 
 892 //------------------------------add_ring---------------------------------------
 893 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
 894   const TypeLong *r0 = t0->is_long(); // Handy access
 895   const TypeLong *r1 = t1->is_long();
 896 
 897   // If either input is not a constant, just return all integers.
 898   if( !r0->is_con() || !r1->is_con() )
 899     return TypeLong::LONG;      // Any integer, but still no symbols.
 900 
 901   // Otherwise just OR them bits.
 902   return TypeLong::make( r0->get_con() | r1->get_con() );
 903 }
 904 
 905 //---------------------------Helper -------------------------------------------
 906 /* Decide if the given node is used only in arithmetic expressions(add or sub).
 907  */
 908 static bool is_used_in_only_arithmetic(Node* n, BasicType bt) {
 909   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 910     Node* u = n->fast_out(i);
 911     if (u->Opcode() != Op_Add(bt) && u->Opcode() != Op_Sub(bt)) {
 912       return false;
 913     }
 914   }
 915   return true;
 916 }
 917 
 918 //=============================================================================
 919 //------------------------------Idealize---------------------------------------
 920 Node* XorINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 921   Node* in1 = in(1);
 922   Node* in2 = in(2);
 923 
 924   // Convert ~x into -1-x when ~x is used in an arithmetic expression
 925   // or x itself is an expression.
 926   if (phase->type(in2) == TypeInt::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
 927     if (phase->is_IterGVN()) {
 928       if (is_used_in_only_arithmetic(this, T_INT)
 929           // LHS is arithmetic
 930           || (in1->Opcode() == Op_AddI || in1->Opcode() == Op_SubI)) {
 931         return new SubINode(in2, in1);
 932       }
 933     } else {
 934       // graph could be incomplete in GVN so we postpone to IGVN
 935       phase->record_for_igvn(this);
 936     }
 937   }
 938 
 939   // Propagate xor through constant cmoves. This pattern can occur after expansion of Conv2B nodes.
 940   const TypeInt* in2_type = phase->type(in2)->isa_int();
 941   if (in1->Opcode() == Op_CMoveI && in2_type != nullptr && in2_type->is_con()) {
 942     int in2_val = in2_type->get_con();
 943 
 944     // Get types of both sides of the CMove
 945     const TypeInt* left = phase->type(in1->in(CMoveNode::IfFalse))->isa_int();
 946     const TypeInt* right = phase->type(in1->in(CMoveNode::IfTrue))->isa_int();
 947 
 948     // Ensure that both sides are int constants
 949     if (left != nullptr && right != nullptr && left->is_con() && right->is_con()) {
 950       Node* cond = in1->in(CMoveNode::Condition);
 951 
 952       // Check that the comparison is a bool and that the cmp node type is correct
 953       if (cond->is_Bool()) {
 954         int cmp_op = cond->in(1)->Opcode();
 955 
 956         if (cmp_op == Op_CmpI || cmp_op == Op_CmpP) {
 957           int l_val = left->get_con();
 958           int r_val = right->get_con();
 959 
 960           return new CMoveINode(cond, phase->intcon(l_val ^ in2_val), phase->intcon(r_val ^ in2_val), TypeInt::INT);
 961         }
 962       }
 963     }
 964   }
 965 
 966   return AddNode::Ideal(phase, can_reshape);
 967 }
 968 
 969 const Type* XorINode::Value(PhaseGVN* phase) const {
 970   Node* in1 = in(1);
 971   Node* in2 = in(2);
 972   const Type* t1 = phase->type(in1);
 973   const Type* t2 = phase->type(in2);
 974   if (t1 == Type::TOP || t2 == Type::TOP) {
 975     return Type::TOP;
 976   }
 977   // x ^ x ==> 0
 978   if (in1->eqv_uncast(in2)) {
 979     return add_id();
 980   }
 981   // result of xor can only have bits sets where any of the
 982   // inputs have bits set. lo can always become 0.
 983   const TypeInt* t1i = t1->is_int();
 984   const TypeInt* t2i = t2->is_int();
 985   if ((t1i->_lo >= 0) &&
 986       (t1i->_hi > 0)  &&
 987       (t2i->_lo >= 0) &&
 988       (t2i->_hi > 0)) {
 989     // hi - set all bits below the highest bit. Using round_down to avoid overflow.
 990     const TypeInt* t1x = TypeInt::make(0, round_down_power_of_2(t1i->_hi) + (round_down_power_of_2(t1i->_hi) - 1), t1i->_widen);
 991     const TypeInt* t2x = TypeInt::make(0, round_down_power_of_2(t2i->_hi) + (round_down_power_of_2(t2i->_hi) - 1), t2i->_widen);
 992     return t1x->meet(t2x);
 993   }
 994   return AddNode::Value(phase);
 995 }
 996 
 997 
 998 //------------------------------add_ring---------------------------------------
 999 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
1000 // the logical operations the ring's ADD is really a logical OR function.
1001 // This also type-checks the inputs for sanity.  Guaranteed never to
1002 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
1003 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
1004   const TypeInt *r0 = t0->is_int(); // Handy access
1005   const TypeInt *r1 = t1->is_int();
1006 
1007   // Complementing a boolean?
1008   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE
1009                                || r1 == TypeInt::BOOL))
1010     return TypeInt::BOOL;
1011 
1012   if( !r0->is_con() || !r1->is_con() ) // Not constants
1013     return TypeInt::INT;        // Any integer, but still no symbols.
1014 
1015   // Otherwise just XOR them bits.
1016   return TypeInt::make( r0->get_con() ^ r1->get_con() );
1017 }
1018 
1019 //=============================================================================
1020 //------------------------------add_ring---------------------------------------
1021 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
1022   const TypeLong *r0 = t0->is_long(); // Handy access
1023   const TypeLong *r1 = t1->is_long();
1024 
1025   // If either input is not a constant, just return all integers.
1026   if( !r0->is_con() || !r1->is_con() )
1027     return TypeLong::LONG;      // Any integer, but still no symbols.
1028 
1029   // Otherwise just OR them bits.
1030   return TypeLong::make( r0->get_con() ^ r1->get_con() );
1031 }
1032 
1033 Node* XorLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1034   Node* in1 = in(1);
1035   Node* in2 = in(2);
1036 
1037   // Convert ~x into -1-x when ~x is used in an arithmetic expression
1038   // or x itself is an arithmetic expression.
1039   if (phase->type(in2) == TypeLong::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
1040     if (phase->is_IterGVN()) {
1041       if (is_used_in_only_arithmetic(this, T_LONG)
1042           // LHS is arithmetic
1043           || (in1->Opcode() == Op_AddL || in1->Opcode() == Op_SubL)) {
1044         return new SubLNode(in2, in1);
1045       }
1046     } else {
1047       // graph could be incomplete in GVN so we postpone to IGVN
1048       phase->record_for_igvn(this);
1049     }
1050   }
1051   return AddNode::Ideal(phase, can_reshape);
1052 }
1053 
1054 const Type* XorLNode::Value(PhaseGVN* phase) const {
1055   Node* in1 = in(1);
1056   Node* in2 = in(2);
1057   const Type* t1 = phase->type(in1);
1058   const Type* t2 = phase->type(in2);
1059   if (t1 == Type::TOP || t2 == Type::TOP) {
1060     return Type::TOP;
1061   }
1062   // x ^ x ==> 0
1063   if (in1->eqv_uncast(in2)) {
1064     return add_id();
1065   }
1066   // result of xor can only have bits sets where any of the
1067   // inputs have bits set. lo can always become 0.
1068   const TypeLong* t1l = t1->is_long();
1069   const TypeLong* t2l = t2->is_long();
1070   if ((t1l->_lo >= 0) &&
1071       (t1l->_hi > 0)  &&
1072       (t2l->_lo >= 0) &&
1073       (t2l->_hi > 0)) {
1074     // hi - set all bits below the highest bit. Using round_down to avoid overflow.
1075     const TypeLong* t1x = TypeLong::make(0, round_down_power_of_2(t1l->_hi) + (round_down_power_of_2(t1l->_hi) - 1), t1l->_widen);
1076     const TypeLong* t2x = TypeLong::make(0, round_down_power_of_2(t2l->_hi) + (round_down_power_of_2(t2l->_hi) - 1), t2l->_widen);
1077     return t1x->meet(t2x);
1078   }
1079   return AddNode::Value(phase);
1080 }
1081 
1082 Node* MaxNode::build_min_max_int(Node* a, Node* b, bool is_max) {
1083   if (is_max) {
1084     return new MaxINode(a, b);
1085   } else {
1086     return new MinINode(a, b);
1087   }
1088 }
1089 
1090 Node* MaxNode::build_min_max_long(PhaseGVN* phase, Node* a, Node* b, bool is_max) {
1091   if (is_max) {
1092     return new MaxLNode(phase->C, a, b);
1093   } else {
1094     return new MinLNode(phase->C, a, b);
1095   }
1096 }
1097 
1098 Node* MaxNode::build_min_max(Node* a, Node* b, bool is_max, bool is_unsigned, const Type* t, PhaseGVN& gvn) {
1099   bool is_int = gvn.type(a)->isa_int();
1100   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1101   assert(is_int == (gvn.type(b)->isa_int() != nullptr), "inconsistent inputs");
1102   BasicType bt = is_int ? T_INT: T_LONG;
1103   Node* hook = nullptr;
1104   if (gvn.is_IterGVN()) {
1105     // Make sure a and b are not destroyed
1106     hook = new Node(2);
1107     hook->init_req(0, a);
1108     hook->init_req(1, b);
1109   }
1110   Node* res = nullptr;
1111   if (is_int && !is_unsigned) {
1112     res = gvn.transform(build_min_max_int(a, b, is_max));
1113     assert(gvn.type(res)->is_int()->_lo >= t->is_int()->_lo && gvn.type(res)->is_int()->_hi <= t->is_int()->_hi, "type doesn't match");
1114   } else {
1115     Node* cmp = nullptr;
1116     if (is_max) {
1117       cmp = gvn.transform(CmpNode::make(a, b, bt, is_unsigned));
1118     } else {
1119       cmp = gvn.transform(CmpNode::make(b, a, bt, is_unsigned));
1120     }
1121     Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1122     res = gvn.transform(CMoveNode::make(bol, a, b, t));
1123   }
1124   if (hook != nullptr) {
1125     hook->destruct(&gvn);
1126   }
1127   return res;
1128 }
1129 
1130 Node* MaxNode::build_min_max_diff_with_zero(Node* a, Node* b, bool is_max, const Type* t, PhaseGVN& gvn) {
1131   bool is_int = gvn.type(a)->isa_int();
1132   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1133   assert(is_int == (gvn.type(b)->isa_int() != nullptr), "inconsistent inputs");
1134   BasicType bt = is_int ? T_INT: T_LONG;
1135   Node* zero = gvn.integercon(0, bt);
1136   Node* hook = nullptr;
1137   if (gvn.is_IterGVN()) {
1138     // Make sure a and b are not destroyed
1139     hook = new Node(2);
1140     hook->init_req(0, a);
1141     hook->init_req(1, b);
1142   }
1143   Node* cmp = nullptr;
1144   if (is_max) {
1145     cmp = gvn.transform(CmpNode::make(a, b, bt, false));
1146   } else {
1147     cmp = gvn.transform(CmpNode::make(b, a, bt, false));
1148   }
1149   Node* sub = gvn.transform(SubNode::make(a, b, bt));
1150   Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1151   Node* res = gvn.transform(CMoveNode::make(bol, sub, zero, t));
1152   if (hook != nullptr) {
1153     hook->destruct(&gvn);
1154   }
1155   return res;
1156 }
1157 
1158 // Check if addition of an integer with type 't' and a constant 'c' can overflow.
1159 static bool can_overflow(const TypeInt* t, jint c) {
1160   jint t_lo = t->_lo;
1161   jint t_hi = t->_hi;
1162   return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
1163           (c > 0 && (java_add(t_hi, c) < t_hi)));
1164 }
1165 
1166 // Let <x, x_off> = x_operands and <y, y_off> = y_operands.
1167 // If x == y and neither add(x, x_off) nor add(y, y_off) overflow, return
1168 // add(x, op(x_off, y_off)). Otherwise, return nullptr.
1169 Node* MaxNode::extract_add(PhaseGVN* phase, ConstAddOperands x_operands, ConstAddOperands y_operands) {
1170   Node* x = x_operands.first;
1171   Node* y = y_operands.first;
1172   int opcode = Opcode();
1173   assert(opcode == Op_MaxI || opcode == Op_MinI, "Unexpected opcode");
1174   const TypeInt* tx = phase->type(x)->isa_int();
1175   jint x_off = x_operands.second;
1176   jint y_off = y_operands.second;
1177   if (x == y && tx != nullptr &&
1178       !can_overflow(tx, x_off) &&
1179       !can_overflow(tx, y_off)) {
1180     jint c = opcode == Op_MinI ? MIN2(x_off, y_off) : MAX2(x_off, y_off);
1181     return new AddINode(x, phase->intcon(c));
1182   }
1183   return nullptr;
1184 }
1185 
1186 // Try to cast n as an integer addition with a constant. Return:
1187 //   <x, C>,       if n == add(x, C), where 'C' is a non-TOP constant;
1188 //   <nullptr, 0>, if n == add(x, C), where 'C' is a TOP constant; or
1189 //   <n, 0>,       otherwise.
1190 static ConstAddOperands as_add_with_constant(Node* n) {
1191   if (n->Opcode() != Op_AddI) {
1192     return ConstAddOperands(n, 0);
1193   }
1194   Node* x = n->in(1);
1195   Node* c = n->in(2);
1196   if (!c->is_Con()) {
1197     return ConstAddOperands(n, 0);
1198   }
1199   const Type* c_type = c->bottom_type();
1200   if (c_type == Type::TOP) {
1201     return ConstAddOperands(nullptr, 0);
1202   }
1203   return ConstAddOperands(x, c_type->is_int()->get_con());
1204 }
1205 
1206 Node* MaxNode::IdealI(PhaseGVN* phase, bool can_reshape) {
1207   int opcode = Opcode();
1208   assert(opcode == Op_MinI || opcode == Op_MaxI, "Unexpected opcode");
1209   // Try to transform the following pattern, in any of its four possible
1210   // permutations induced by op's commutativity:
1211   //     op(op(add(inner, inner_off), inner_other), add(outer, outer_off))
1212   // into
1213   //     op(add(inner, op(inner_off, outer_off)), inner_other),
1214   // where:
1215   //     op is either MinI or MaxI, and
1216   //     inner == outer, and
1217   //     the additions cannot overflow.
1218   for (uint inner_op_index = 1; inner_op_index <= 2; inner_op_index++) {
1219     if (in(inner_op_index)->Opcode() != opcode) {
1220       continue;
1221     }
1222     Node* outer_add = in(inner_op_index == 1 ? 2 : 1);
1223     ConstAddOperands outer_add_operands = as_add_with_constant(outer_add);
1224     if (outer_add_operands.first == nullptr) {
1225       return nullptr; // outer_add has a TOP input, no need to continue.
1226     }
1227     // One operand is a MinI/MaxI and the other is an integer addition with
1228     // constant. Test the operands of the inner MinI/MaxI.
1229     for (uint inner_add_index = 1; inner_add_index <= 2; inner_add_index++) {
1230       Node* inner_op = in(inner_op_index);
1231       Node* inner_add = inner_op->in(inner_add_index);
1232       ConstAddOperands inner_add_operands = as_add_with_constant(inner_add);
1233       if (inner_add_operands.first == nullptr) {
1234         return nullptr; // inner_add has a TOP input, no need to continue.
1235       }
1236       // Try to extract the inner add.
1237       Node* add_extracted = extract_add(phase, inner_add_operands, outer_add_operands);
1238       if (add_extracted == nullptr) {
1239         continue;
1240       }
1241       Node* add_transformed = phase->transform(add_extracted);
1242       Node* inner_other = inner_op->in(inner_add_index == 1 ? 2 : 1);
1243       return build_min_max_int(add_transformed, inner_other, opcode == Op_MaxI);
1244     }
1245   }
1246   // Try to transform
1247   //     op(add(x, x_off), add(y, y_off))
1248   // into
1249   //     add(x, op(x_off, y_off)),
1250   // where:
1251   //     op is either MinI or MaxI, and
1252   //     inner == outer, and
1253   //     the additions cannot overflow.
1254   ConstAddOperands xC = as_add_with_constant(in(1));
1255   ConstAddOperands yC = as_add_with_constant(in(2));
1256   if (xC.first == nullptr || yC.first == nullptr) return nullptr;
1257   return extract_add(phase, xC, yC);
1258 }
1259 
1260 // Ideal transformations for MaxINode
1261 Node* MaxINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1262   return IdealI(phase, can_reshape);
1263 }
1264 
1265 Node* MaxINode::Identity(PhaseGVN* phase) {
1266   const TypeInt* t1 = phase->type(in(1))->is_int();
1267   const TypeInt* t2 = phase->type(in(2))->is_int();
1268 
1269   // Can we determine the maximum statically?
1270   if (t1->_lo >= t2->_hi) {
1271     return in(1);
1272   } else if (t2->_lo >= t1->_hi) {
1273     return in(2);
1274   }
1275 
1276   return MaxNode::Identity(phase);
1277 }
1278 
1279 //=============================================================================
1280 //------------------------------add_ring---------------------------------------
1281 // Supplied function returns the sum of the inputs.
1282 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
1283   const TypeInt *r0 = t0->is_int(); // Handy access
1284   const TypeInt *r1 = t1->is_int();
1285 
1286   // Otherwise just MAX them bits.
1287   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1288 }
1289 
1290 //=============================================================================
1291 //------------------------------Idealize---------------------------------------
1292 // MINs show up in range-check loop limit calculations.  Look for
1293 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
1294 Node* MinINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1295   return IdealI(phase, can_reshape);
1296 }
1297 
1298 Node* MinINode::Identity(PhaseGVN* phase) {
1299   const TypeInt* t1 = phase->type(in(1))->is_int();
1300   const TypeInt* t2 = phase->type(in(2))->is_int();
1301 
1302   // Can we determine the minimum statically?
1303   if (t1->_lo >= t2->_hi) {
1304     return in(2);
1305   } else if (t2->_lo >= t1->_hi) {
1306     return in(1);
1307   }
1308 
1309   return MaxNode::Identity(phase);
1310 }
1311 
1312 //------------------------------add_ring---------------------------------------
1313 // Supplied function returns the sum of the inputs.
1314 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
1315   const TypeInt *r0 = t0->is_int(); // Handy access
1316   const TypeInt *r1 = t1->is_int();
1317 
1318   // Otherwise just MIN them bits.
1319   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1320 }
1321 
1322 // Collapse the "addition with overflow-protection" pattern, and the symmetrical
1323 // "subtraction with underflow-protection" pattern. These are created during the
1324 // unrolling, when we have to adjust the limit by subtracting the stride, but want
1325 // to protect against underflow: MaxL(SubL(limit, stride), min_jint).
1326 // If we have more than one of those in a sequence:
1327 //
1328 //   x  con2
1329 //   |  |
1330 //   AddL  clamp2
1331 //     |    |
1332 //    Max/MinL con1
1333 //          |  |
1334 //          AddL  clamp1
1335 //            |    |
1336 //           Max/MinL (n)
1337 //
1338 // We want to collapse it to:
1339 //
1340 //   x  con1  con2
1341 //   |    |    |
1342 //   |   AddLNode (new_con)
1343 //   |    |
1344 //  AddLNode  clamp1
1345 //        |    |
1346 //       Max/MinL (n)
1347 //
1348 // Note: we assume that SubL was already replaced by an AddL, and that the stride
1349 // has its sign flipped: SubL(limit, stride) -> AddL(limit, -stride).
1350 static Node* fold_subI_no_underflow_pattern(Node* n, PhaseGVN* phase) {
1351   assert(n->Opcode() == Op_MaxL || n->Opcode() == Op_MinL, "sanity");
1352   // Check that the two clamps have the correct values.
1353   jlong clamp = (n->Opcode() == Op_MaxL) ? min_jint : max_jint;
1354   auto is_clamp = [&](Node* c) {
1355     const TypeLong* t = phase->type(c)->isa_long();
1356     return t != nullptr && t->is_con() &&
1357            t->get_con() == clamp;
1358   };
1359   // Check that the constants are negative if MaxL, and positive if MinL.
1360   auto is_sub_con = [&](Node* c) {
1361     const TypeLong* t = phase->type(c)->isa_long();
1362     return t != nullptr && t->is_con() &&
1363            t->get_con() < max_jint && t->get_con() > min_jint &&
1364            (t->get_con() < 0) == (n->Opcode() == Op_MaxL);
1365   };
1366   // Verify the graph level by level:
1367   Node* add1   = n->in(1);
1368   Node* clamp1 = n->in(2);
1369   if (add1->Opcode() == Op_AddL && is_clamp(clamp1)) {
1370     Node* max2 = add1->in(1);
1371     Node* con1 = add1->in(2);
1372     if (max2->Opcode() == n->Opcode() && is_sub_con(con1)) {
1373       Node* add2   = max2->in(1);
1374       Node* clamp2 = max2->in(2);
1375       if (add2->Opcode() == Op_AddL && is_clamp(clamp2)) {
1376         Node* x    = add2->in(1);
1377         Node* con2 = add2->in(2);
1378         if (is_sub_con(con2)) {
1379           Node* new_con = phase->transform(new AddLNode(con1, con2));
1380           Node* new_sub = phase->transform(new AddLNode(x, new_con));
1381           n->set_req_X(1, new_sub, phase);
1382           return n;
1383         }
1384       }
1385     }
1386   }
1387   return nullptr;
1388 }
1389 
1390 const Type* MaxLNode::add_ring(const Type* t0, const Type* t1) const {
1391   const TypeLong* r0 = t0->is_long();
1392   const TypeLong* r1 = t1->is_long();
1393 
1394   return TypeLong::make(MAX2(r0->_lo, r1->_lo), MAX2(r0->_hi, r1->_hi), MAX2(r0->_widen, r1->_widen));
1395 }
1396 
1397 Node* MaxLNode::Identity(PhaseGVN* phase) {
1398   const TypeLong* t1 = phase->type(in(1))->is_long();
1399   const TypeLong* t2 = phase->type(in(2))->is_long();
1400 
1401   // Can we determine maximum statically?
1402   if (t1->_lo >= t2->_hi) {
1403     return in(1);
1404   } else if (t2->_lo >= t1->_hi) {
1405     return in(2);
1406   }
1407 
1408   return MaxNode::Identity(phase);
1409 }
1410 
1411 Node* MaxLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1412   Node* n = AddNode::Ideal(phase, can_reshape);
1413   if (n != nullptr) {
1414     return n;
1415   }
1416   if (can_reshape) {
1417     return fold_subI_no_underflow_pattern(this, phase);
1418   }
1419   return nullptr;
1420 }
1421 
1422 const Type* MinLNode::add_ring(const Type* t0, const Type* t1) const {
1423   const TypeLong* r0 = t0->is_long();
1424   const TypeLong* r1 = t1->is_long();
1425 
1426   return TypeLong::make(MIN2(r0->_lo, r1->_lo), MIN2(r0->_hi, r1->_hi), MAX2(r0->_widen, r1->_widen));
1427 }
1428 
1429 Node* MinLNode::Identity(PhaseGVN* phase) {
1430   const TypeLong* t1 = phase->type(in(1))->is_long();
1431   const TypeLong* t2 = phase->type(in(2))->is_long();
1432 
1433   // Can we determine minimum statically?
1434   if (t1->_lo >= t2->_hi) {
1435     return in(2);
1436   } else if (t2->_lo >= t1->_hi) {
1437     return in(1);
1438   }
1439 
1440   return MaxNode::Identity(phase);
1441 }
1442 
1443 Node* MinLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1444   Node* n = AddNode::Ideal(phase, can_reshape);
1445   if (n != nullptr) {
1446     return n;
1447   }
1448   if (can_reshape) {
1449     return fold_subI_no_underflow_pattern(this, phase);
1450   }
1451   return nullptr;
1452 }
1453 
1454 int MaxNode::opposite_opcode() const {
1455   if (Opcode() == max_opcode()) {
1456     return min_opcode();
1457   } else {
1458     assert(Opcode() == min_opcode(), "Caller should be either %s or %s, but is %s", NodeClassNames[max_opcode()], NodeClassNames[min_opcode()], NodeClassNames[Opcode()]);
1459     return max_opcode();
1460   }
1461 }
1462 
1463 // Given a redundant structure such as Max/Min(A, Max/Min(B, C)) where A == B or A == C, return the useful part of the structure.
1464 // 'operation' is the node expected to be the inner 'Max/Min(B, C)', and 'operand' is the node expected to be the 'A' operand of the outer node.
1465 Node* MaxNode::find_identity_operation(Node* operation, Node* operand) {
1466   if (operation->Opcode() == Opcode() || operation->Opcode() == opposite_opcode()) {
1467     Node* n1 = operation->in(1);
1468     Node* n2 = operation->in(2);
1469 
1470     // Given Op(A, Op(B, C)), see if either A == B or A == C is true.
1471     if (n1 == operand || n2 == operand) {
1472       // If the operations are the same return the inner operation, as Max(A, Max(A, B)) == Max(A, B).
1473       if (operation->Opcode() == Opcode()) {
1474         return operation;
1475       }
1476 
1477       // If the operations are different return the operand 'A', as Max(A, Min(A, B)) == A if the value isn't floating point.
1478       // With floating point values, the identity doesn't hold if B == NaN.
1479       const Type* type = bottom_type();
1480       if (type->isa_int() || type->isa_long()) {
1481         return operand;
1482       }
1483     }
1484   }
1485 
1486   return nullptr;
1487 }
1488 
1489 Node* MaxNode::Identity(PhaseGVN* phase) {
1490   if (in(1) == in(2)) {
1491       return in(1);
1492   }
1493 
1494   Node* identity_1 = MaxNode::find_identity_operation(in(2), in(1));
1495   if (identity_1 != nullptr) {
1496     return identity_1;
1497   }
1498 
1499   Node* identity_2 = MaxNode::find_identity_operation(in(1), in(2));
1500   if (identity_2 != nullptr) {
1501     return identity_2;
1502   }
1503 
1504   return AddNode::Identity(phase);
1505 }
1506 
1507 //------------------------------add_ring---------------------------------------
1508 const Type* MinFNode::add_ring(const Type* t0, const Type* t1 ) const {
1509   const TypeF* r0 = t0->isa_float_constant();
1510   const TypeF* r1 = t1->isa_float_constant();
1511   if (r0 == nullptr || r1 == nullptr) {
1512     return bottom_type();
1513   }
1514 
1515   if (r0->is_nan()) {
1516     return r0;
1517   }
1518   if (r1->is_nan()) {
1519     return r1;
1520   }
1521 
1522   float f0 = r0->getf();
1523   float f1 = r1->getf();
1524   if (f0 != 0.0f || f1 != 0.0f) {
1525     return f0 < f1 ? r0 : r1;
1526   }
1527 
1528   // handle min of 0.0, -0.0 case.
1529   return (jint_cast(f0) < jint_cast(f1)) ? r0 : r1;
1530 }
1531 
1532 //------------------------------add_ring---------------------------------------
1533 const Type* MinDNode::add_ring(const Type* t0, const Type* t1) const {
1534   const TypeD* r0 = t0->isa_double_constant();
1535   const TypeD* r1 = t1->isa_double_constant();
1536   if (r0 == nullptr || r1 == nullptr) {
1537     return bottom_type();
1538   }
1539 
1540   if (r0->is_nan()) {
1541     return r0;
1542   }
1543   if (r1->is_nan()) {
1544     return r1;
1545   }
1546 
1547   double d0 = r0->getd();
1548   double d1 = r1->getd();
1549   if (d0 != 0.0 || d1 != 0.0) {
1550     return d0 < d1 ? r0 : r1;
1551   }
1552 
1553   // handle min of 0.0, -0.0 case.
1554   return (jlong_cast(d0) < jlong_cast(d1)) ? r0 : r1;
1555 }
1556 
1557 //------------------------------add_ring---------------------------------------
1558 const Type* MaxFNode::add_ring(const Type* t0, const Type* t1) const {
1559   const TypeF* r0 = t0->isa_float_constant();
1560   const TypeF* r1 = t1->isa_float_constant();
1561   if (r0 == nullptr || r1 == nullptr) {
1562     return bottom_type();
1563   }
1564 
1565   if (r0->is_nan()) {
1566     return r0;
1567   }
1568   if (r1->is_nan()) {
1569     return r1;
1570   }
1571 
1572   float f0 = r0->getf();
1573   float f1 = r1->getf();
1574   if (f0 != 0.0f || f1 != 0.0f) {
1575     return f0 > f1 ? r0 : r1;
1576   }
1577 
1578   // handle max of 0.0,-0.0 case.
1579   return (jint_cast(f0) > jint_cast(f1)) ? r0 : r1;
1580 }
1581 
1582 //------------------------------add_ring---------------------------------------
1583 const Type* MaxDNode::add_ring(const Type* t0, const Type* t1) const {
1584   const TypeD* r0 = t0->isa_double_constant();
1585   const TypeD* r1 = t1->isa_double_constant();
1586   if (r0 == nullptr || r1 == nullptr) {
1587     return bottom_type();
1588   }
1589 
1590   if (r0->is_nan()) {
1591     return r0;
1592   }
1593   if (r1->is_nan()) {
1594     return r1;
1595   }
1596 
1597   double d0 = r0->getd();
1598   double d1 = r1->getd();
1599   if (d0 != 0.0 || d1 != 0.0) {
1600     return d0 > d1 ? r0 : r1;
1601   }
1602 
1603   // handle max of 0.0, -0.0 case.
1604   return (jlong_cast(d0) > jlong_cast(d1)) ? r0 : r1;
1605 }