1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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  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.
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  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
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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 #include "opto/utilities/xor.hpp"
  36 #include "runtime/stubRoutines.hpp"
  37 
  38 // Portions of code courtesy of Clifford Click
  39 
  40 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  41 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  42 // all inherited from this class.  The various identity values are supplied
  43 // by virtual functions.
  44 
  45 
  46 //=============================================================================
  47 //------------------------------hash-------------------------------------------
  48 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  49 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  50 // the same value in the presence of edge swapping.
  51 uint AddNode::hash() const {
  52   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  53 }
  54 
  55 //------------------------------Identity---------------------------------------
  56 // If either input is a constant 0, return the other input.
  57 Node* AddNode::Identity(PhaseGVN* phase) {
  58   const Type *zero = add_id();  // The additive identity
  59   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  60   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  61   return this;
  62 }
  63 
  64 //------------------------------commute----------------------------------------
  65 // Commute operands to move loads and constants to the right.
  66 static bool commute(PhaseGVN* phase, Node* add) {
  67   Node *in1 = add->in(1);
  68   Node *in2 = add->in(2);
  69 
  70   // convert "max(a,b) + min(a,b)" into "a+b".
  71   if ((in1->Opcode() == add->as_Add()->max_opcode() && in2->Opcode() == add->as_Add()->min_opcode())
  72       || (in1->Opcode() == add->as_Add()->min_opcode() && in2->Opcode() == add->as_Add()->max_opcode())) {
  73     Node *in11 = in1->in(1);
  74     Node *in12 = in1->in(2);
  75 
  76     Node *in21 = in2->in(1);
  77     Node *in22 = in2->in(2);
  78 
  79     if ((in11 == in21 && in12 == in22) ||
  80         (in11 == in22 && in12 == in21)) {
  81       add->set_req_X(1, in11, phase);
  82       add->set_req_X(2, in12, phase);
  83       return true;
  84     }
  85   }
  86 
  87   bool con_left = phase->type(in1)->singleton();
  88   bool con_right = phase->type(in2)->singleton();
  89 
  90   // Convert "1+x" into "x+1".
  91   // Right is a constant; leave it
  92   if( con_right ) return false;
  93   // Left is a constant; move it right.
  94   if( con_left ) {
  95     add->swap_edges(1, 2);
  96     return true;
  97   }
  98 
  99   // Convert "Load+x" into "x+Load".
 100   // Now check for loads
 101   if (in2->is_Load()) {
 102     if (!in1->is_Load()) {
 103       // already x+Load to return
 104       return false;
 105     }
 106     // both are loads, so fall through to sort inputs by idx
 107   } else if( in1->is_Load() ) {
 108     // Left is a Load and Right is not; move it right.
 109     add->swap_edges(1, 2);
 110     return true;
 111   }
 112 
 113   PhiNode *phi;
 114   // Check for tight loop increments: Loop-phi of Add of loop-phi
 115   if (in1->is_Phi() && (phi = in1->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add)
 116     return false;
 117   if (in2->is_Phi() && (phi = in2->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add) {
 118     add->swap_edges(1, 2);
 119     return true;
 120   }
 121 
 122   // Otherwise, sort inputs (commutativity) to help value numbering.
 123   if( in1->_idx > in2->_idx ) {
 124     add->swap_edges(1, 2);
 125     return true;
 126   }
 127   return false;
 128 }
 129 
 130 //------------------------------Idealize---------------------------------------
 131 // If we get here, we assume we are associative!
 132 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 133   const Type *t1 = phase->type(in(1));
 134   const Type *t2 = phase->type(in(2));
 135   bool con_left  = t1->singleton();
 136   bool con_right = t2->singleton();
 137 
 138   // Check for commutative operation desired
 139   if (commute(phase, this)) return this;
 140 
 141   AddNode *progress = nullptr;             // Progress flag
 142 
 143   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 144   // constant, and the left input is an add of a constant, flatten the
 145   // expression tree.
 146   Node *add1 = in(1);
 147   Node *add2 = in(2);
 148   int add1_op = add1->Opcode();
 149   int this_op = Opcode();
 150   if (con_right && t2 != Type::TOP && // Right input is a constant?
 151       add1_op == this_op) { // Left input is an Add?
 152 
 153     // Type of left _in right input
 154     const Type *t12 = phase->type(add1->in(2));
 155     if (t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
 156       // Check for rare case of closed data cycle which can happen inside
 157       // unreachable loops. In these cases the computation is undefined.
 158 #ifdef ASSERT
 159       Node *add11    = add1->in(1);
 160       int   add11_op = add11->Opcode();
 161       if ((add1 == add1->in(1))
 162           || (add11_op == this_op && add11->in(1) == add1)) {
 163         assert(false, "dead loop in AddNode::Ideal");
 164       }
 165 #endif
 166       // The Add of the flattened expression
 167       Node *x1 = add1->in(1);
 168       Node *x2 = phase->makecon(add1->as_Add()->add_ring(t2, t12));
 169       set_req_X(2, x2, phase);
 170       set_req_X(1, x1, phase);
 171       progress = this;            // Made progress
 172       add1 = in(1);
 173       add1_op = add1->Opcode();
 174     }
 175   }
 176 
 177   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 178   if (add1_op == this_op && !con_right) {
 179     Node *a12 = add1->in(2);
 180     const Type *t12 = phase->type( a12 );
 181     if (t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 182         !(add1->in(1)->is_Phi() && (add1->in(1)->as_Phi()->is_tripcount(T_INT) || add1->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 183       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 184       add2 = add1->clone();
 185       add2->set_req(2, in(2));
 186       add2 = phase->transform(add2);
 187       set_req_X(1, add2, phase);
 188       set_req_X(2, a12, phase);
 189       progress = this;
 190       add2 = a12;
 191     }
 192   }
 193 
 194   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 195   int add2_op = add2->Opcode();
 196   if (add2_op == this_op && !con_left) {
 197     Node *a22 = add2->in(2);
 198     const Type *t22 = phase->type( a22 );
 199     if (t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 200         !(add2->in(1)->is_Phi() && (add2->in(1)->as_Phi()->is_tripcount(T_INT) || add2->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 201       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 202       Node *addx = add2->clone();
 203       addx->set_req(1, in(1));
 204       addx->set_req(2, add2->in(1));
 205       addx = phase->transform(addx);
 206       set_req_X(1, addx, phase);
 207       set_req_X(2, a22, phase);
 208       progress = this;
 209     }
 210   }
 211 
 212   return progress;
 213 }
 214 
 215 //------------------------------Value-----------------------------------------
 216 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 217 // the other input's symbols.
 218 const Type* AddNode::Value(PhaseGVN* phase) const {
 219   // Either input is TOP ==> the result is TOP
 220   const Type* t1 = phase->type(in(1));
 221   const Type* t2 = phase->type(in(2));
 222   if (t1 == Type::TOP || t2 == Type::TOP) {
 223     return Type::TOP;
 224   }
 225 
 226   // Check for an addition involving the additive identity
 227   const Type* tadd = add_of_identity(t1, t2);
 228   if (tadd != nullptr) {
 229     return tadd;
 230   }
 231 
 232   return add_ring(t1, t2);               // Local flavor of type addition
 233 }
 234 
 235 //------------------------------add_identity-----------------------------------
 236 // Check for addition of the identity
 237 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 238   const Type *zero = add_id();  // The additive identity
 239   if( t1->higher_equal( zero ) ) return t2;
 240   if( t2->higher_equal( zero ) ) return t1;
 241 
 242   return nullptr;
 243 }
 244 
 245 AddNode* AddNode::make(Node* in1, Node* in2, BasicType bt) {
 246   switch (bt) {
 247     case T_INT:
 248       return new AddINode(in1, in2);
 249     case T_LONG:
 250       return new AddLNode(in1, in2);
 251     default:
 252       fatal("Not implemented for %s", type2name(bt));
 253   }
 254   return nullptr;
 255 }
 256 
 257 bool AddNode::is_not(PhaseGVN* phase, Node* n, BasicType bt) {
 258   return n->Opcode() == Op_Xor(bt) && phase->type(n->in(2)) == TypeInteger::minus_1(bt);
 259 }
 260 
 261 AddNode* AddNode::make_not(PhaseGVN* phase, Node* n, BasicType bt) {
 262   switch (bt) {
 263     case T_INT:
 264       return new XorINode(n, phase->intcon(-1));
 265     case T_LONG:
 266       return new XorLNode(n, phase->longcon(-1L));
 267     default:
 268       fatal("Not implemented for %s", type2name(bt));
 269   }
 270   return nullptr;
 271 }
 272 
 273 //=============================================================================
 274 //------------------------------Idealize---------------------------------------
 275 Node* AddNode::IdealIL(PhaseGVN* phase, bool can_reshape, BasicType bt) {
 276   Node* in1 = in(1);
 277   Node* in2 = in(2);
 278   int op1 = in1->Opcode();
 279   int op2 = in2->Opcode();
 280   // Fold (con1-x)+con2 into (con1+con2)-x
 281   if (op1 == Op_Add(bt) && op2 == Op_Sub(bt)) {
 282     // Swap edges to try optimizations below
 283     in1 = in2;
 284     in2 = in(1);
 285     op1 = op2;
 286     op2 = in2->Opcode();
 287   }
 288   if (op1 == Op_Sub(bt)) {
 289     const Type* t_sub1 = phase->type(in1->in(1));
 290     const Type* t_2    = phase->type(in2       );
 291     if (t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP) {
 292       return SubNode::make(phase->makecon(add_ring(t_sub1, t_2)), in1->in(2), bt);
 293     }
 294     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 295     if (op2 == Op_Sub(bt)) {
 296       // Check for dead cycle: d = (a-b)+(c-d)
 297       assert( in1->in(2) != this && in2->in(2) != this,
 298               "dead loop in AddINode::Ideal" );
 299       Node* sub = SubNode::make(nullptr, nullptr, bt);
 300       Node* sub_in1;
 301       PhaseIterGVN* igvn = phase->is_IterGVN();
 302       // During IGVN, if both inputs of the new AddNode are a tree of SubNodes, this same transformation will be applied
 303       // to every node of the tree. Calling transform() causes the transformation to be applied recursively, once per
 304       // tree node whether some subtrees are identical or not. Pushing to the IGVN worklist instead, causes the transform
 305       // to be applied once per unique subtrees (because all uses of a subtree are updated with the result of the
 306       // transformation). In case of a large tree, this can make a difference in compilation time.
 307       if (igvn != nullptr) {
 308         sub_in1 = igvn->register_new_node_with_optimizer(AddNode::make(in1->in(1), in2->in(1), bt));
 309       } else {
 310         sub_in1 = phase->transform(AddNode::make(in1->in(1), in2->in(1), bt));
 311       }
 312       Node* sub_in2;
 313       if (igvn != nullptr) {
 314         sub_in2 = igvn->register_new_node_with_optimizer(AddNode::make(in1->in(2), in2->in(2), bt));
 315       } else {
 316         sub_in2 = phase->transform(AddNode::make(in1->in(2), in2->in(2), bt));
 317       }
 318       sub->init_req(1, sub_in1);
 319       sub->init_req(2, sub_in2);
 320       return sub;
 321     }
 322     // Convert "(a-b)+(b+c)" into "(a+c)"
 323     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(1)) {
 324       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 325       return AddNode::make(in1->in(1), in2->in(2), bt);
 326     }
 327     // Convert "(a-b)+(c+b)" into "(a+c)"
 328     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(2)) {
 329       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 330       return AddNode::make(in1->in(1), in2->in(1), bt);
 331     }
 332   }
 333 
 334   // Convert (con - y) + x into "(x - y) + con"
 335   if (op1 == Op_Sub(bt) && in1->in(1)->Opcode() == Op_ConIL(bt)
 336       && in1 != in1->in(2) && !(in1->in(2)->is_Phi() && in1->in(2)->as_Phi()->is_tripcount(bt))) {
 337     return AddNode::make(phase->transform(SubNode::make(in2, in1->in(2), bt)), in1->in(1), bt);
 338   }
 339 
 340   // Convert x + (con - y) into "(x - y) + con"
 341   if (op2 == Op_Sub(bt) && in2->in(1)->Opcode() == Op_ConIL(bt)
 342       && in2 != in2->in(2) && !(in2->in(2)->is_Phi() && in2->in(2)->as_Phi()->is_tripcount(bt))) {
 343     return AddNode::make(phase->transform(SubNode::make(in1, in2->in(2), bt)), in2->in(1), bt);
 344   }
 345 
 346   // Associative
 347   if (op1 == Op_Mul(bt) && op2 == Op_Mul(bt)) {
 348     Node* add_in1 = nullptr;
 349     Node* add_in2 = nullptr;
 350     Node* mul_in = nullptr;
 351 
 352     if (in1->in(1) == in2->in(1)) {
 353       // Convert "a*b+a*c into a*(b+c)
 354       add_in1 = in1->in(2);
 355       add_in2 = in2->in(2);
 356       mul_in = in1->in(1);
 357     } else if (in1->in(2) == in2->in(1)) {
 358       // Convert a*b+b*c into b*(a+c)
 359       add_in1 = in1->in(1);
 360       add_in2 = in2->in(2);
 361       mul_in = in1->in(2);
 362     } else if (in1->in(2) == in2->in(2)) {
 363       // Convert a*c+b*c into (a+b)*c
 364       add_in1 = in1->in(1);
 365       add_in2 = in2->in(1);
 366       mul_in = in1->in(2);
 367     } else if (in1->in(1) == in2->in(2)) {
 368       // Convert a*b+c*a into a*(b+c)
 369       add_in1 = in1->in(2);
 370       add_in2 = in2->in(1);
 371       mul_in = in1->in(1);
 372     }
 373 
 374     if (mul_in != nullptr) {
 375       Node* add = phase->transform(AddNode::make(add_in1, add_in2, bt));
 376       return MulNode::make(mul_in, add, bt);
 377     }
 378   }
 379 
 380   // Convert (x >>> rshift) + (x << lshift) into RotateRight(x, rshift)
 381   if (Matcher::match_rule_supported(Op_RotateRight) &&
 382       ((op1 == Op_URShift(bt) && op2 == Op_LShift(bt)) || (op1 == Op_LShift(bt) && op2 == Op_URShift(bt))) &&
 383       in1->in(1) != nullptr && in1->in(1) == in2->in(1)) {
 384     Node* rshift = op1 == Op_URShift(bt) ? in1->in(2) : in2->in(2);
 385     Node* lshift = op1 == Op_URShift(bt) ? in2->in(2) : in1->in(2);
 386     if (rshift != nullptr && lshift != nullptr) {
 387       const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 388       const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 389       int bits = bt == T_INT ? 32 : 64;
 390       int mask = bt == T_INT ? 0x1F : 0x3F;
 391       if (lshift_t != nullptr && lshift_t->is_con() &&
 392           rshift_t != nullptr && rshift_t->is_con() &&
 393           ((lshift_t->get_con() & mask) == (bits - (rshift_t->get_con() & mask)))) {
 394         return new RotateRightNode(in1->in(1), phase->intcon(rshift_t->get_con() & mask), TypeInteger::bottom(bt));
 395       }
 396     }
 397   }
 398 
 399   // Collapse addition of the same terms into multiplications.
 400   Node* collapsed = Ideal_collapse_variable_times_con(phase, bt);
 401   if (collapsed != nullptr) {
 402     return collapsed; // Skip AddNode::Ideal() since it may now be a multiplication node.
 403   }
 404 
 405   return AddNode::Ideal(phase, can_reshape);
 406 }
 407 
 408 // Try to collapse addition of the same terms into a single multiplication. On success, a new MulNode is returned.
 409 // Examples of this conversion includes:
 410 //   - a + a + ... + a => CON*a
 411 //   - (a * CON) + a   => (CON + 1) * a
 412 //   - a + (a * CON)   => (CON + 1) * a
 413 //
 414 // We perform such conversions incrementally during IGVN by transforming left most nodes first and work up to the root
 415 // of the expression. In other words, we convert, at each iteration:
 416 //        a + a + a + ... + a
 417 //     => 2*a + a + ... + a
 418 //     => 3*a + ... + a
 419 //     => n*a
 420 //
 421 // Due to the iterative nature of IGVN, MulNode transformed from first few AddNode terms may be further transformed into
 422 // power-of-2 pattern. (e.g., 2 * a => a << 1, 3 * a => (a << 2) + a). We can't guarantee we'll always pick up
 423 // transformed power-of-2 patterns when term `a` is complex.
 424 //
 425 // Note this also converts, for example, original expression `(a*3) + a` into `4*a` and `(a<<2) + a` into `5*a`. A more
 426 // generalized pattern `(a*b) + (a*c)` into `a*(b + c)` is handled by AddNode::IdealIL().
 427 Node* AddNode::Ideal_collapse_variable_times_con(PhaseGVN* phase, BasicType bt) {
 428   // We need to make sure that the current AddNode is not part of a MulNode that has already been optimized to a
 429   // power-of-2 addition (e.g., 3 * a => (a << 2) + a). Without this check, GVN would keep trying to optimize the same
 430   // node and can't progress. For example, 3 * a => (a << 2) + a => 3 * a => (a << 2) + a => ...
 431   if (Multiplication::find_power_of_two_addition_pattern(this, bt).is_valid()) {
 432     return nullptr;
 433   }
 434 
 435   Node* lhs = in(1);
 436   Node* rhs = in(2);
 437 
 438   Multiplication mul = Multiplication::find_collapsible_addition_patterns(lhs, rhs, bt);
 439   if (!mul.is_valid_with(rhs)) {
 440     // Swap lhs and rhs then try again
 441     mul = Multiplication::find_collapsible_addition_patterns(rhs, lhs, bt);
 442     if (!mul.is_valid_with(lhs)) {
 443       return nullptr;
 444     }
 445   }
 446 
 447   Node* con;
 448   if (bt == T_INT) {
 449     con = phase->intcon(java_add(static_cast<jint>(mul.multiplier()), 1));
 450   } else {
 451     con = phase->longcon(java_add(mul.multiplier(), CONST64(1)));
 452   }
 453 
 454   return MulNode::make(con, mul.variable(), bt);
 455 }
 456 
 457 // Find a pattern of collapsable additions that can be converted to a multiplication.
 458 // When matching the LHS `a * CON`, we match with best efforts by looking for the following patterns:
 459 //     - (1) Simple addition:       LHS = a + a
 460 //     - (2) Simple lshift:         LHS = a << CON
 461 //     - (3) Simple multiplication: LHS = CON * a
 462 //     - (4) Power-of-two addition: LHS = (a << CON1) + (a << CON2)
 463 AddNode::Multiplication AddNode::Multiplication::find_collapsible_addition_patterns(const Node* a, const Node* pattern, BasicType bt) {
 464   // (1) Simple addition pattern (e.g., lhs = a + a)
 465   Multiplication mul = find_simple_addition_pattern(a, bt);
 466   if (mul.is_valid_with(pattern)) {
 467     return mul;
 468   }
 469 
 470   // (2) Simple lshift pattern (e.g., lhs = a << CON)
 471   mul = find_simple_lshift_pattern(a, bt);
 472   if (mul.is_valid_with(pattern)) {
 473     return mul;
 474   }
 475 
 476   // (3) Simple multiplication pattern (e.g., lhs = CON * a)
 477   mul = find_simple_multiplication_pattern(a, bt);
 478   if (mul.is_valid_with(pattern)) {
 479     return mul;
 480   }
 481 
 482   // (4) Power-of-two addition pattern (e.g., lhs = (a << CON1) + (a << CON2))
 483   // While multiplications can be potentially optimized to power-of-2 subtractions (e.g., a * 7 => (a << 3) - a),
 484   // (x - y) + y => x is already handled by the Identity() methods. So, we don't need to check for that pattern here.
 485   mul = find_power_of_two_addition_pattern(a, bt);
 486   if (mul.is_valid_with(pattern)) {
 487     return mul;
 488   }
 489 
 490   // We've tried everything.
 491   return make_invalid();
 492 }
 493 
 494 // Try to match `n = a + a`. On success, return a struct with `.valid = true`, `variable = a`, and `multiplier = 2`.
 495 // The method matches `n` for pattern: a + a.
 496 AddNode::Multiplication AddNode::Multiplication::find_simple_addition_pattern(const Node* n, BasicType bt) {
 497   if (n->Opcode() == Op_Add(bt) && n->in(1) == n->in(2)) {
 498     return Multiplication(n->in(1), 2);
 499   }
 500 
 501   return make_invalid();
 502 }
 503 
 504 // Try to match `n = a << CON`. On success, return a struct with `.valid = true`, `variable = a`, and
 505 // `multiplier = 1 << CON`.
 506 // Match `n` for pattern: a << CON.
 507 // Note that the power-of-2 multiplication optimization could potentially convert a MulNode to this pattern.
 508 AddNode::Multiplication AddNode::Multiplication::find_simple_lshift_pattern(const Node* n, BasicType bt) {
 509   // Note that power-of-2 multiplication optimization could potentially convert a MulNode to this pattern
 510   if (n->Opcode() == Op_LShift(bt) && n->in(2)->is_Con()) {
 511     Node* con = n->in(2);
 512     if (!con->is_top()) {
 513       return Multiplication(n->in(1), java_shift_left(1, con->get_int(), bt));
 514     }
 515   }
 516 
 517   return make_invalid();
 518 }
 519 
 520 // Try to match `n = CON * a`. On success, return a struct with `.valid = true`, `variable = a`, and `multiplier = CON`.
 521 // Match `n` for patterns: CON * a
 522 // Note that `CON` will always be the second input node of a Mul node canonicalized by Ideal(). If this is not the case,
 523 // `n` has not been processed by iGVN. So we skip the optimization for the current add node and wait for to be added to
 524 // the queue again.
 525 AddNode::Multiplication AddNode::Multiplication::find_simple_multiplication_pattern(const Node* n, BasicType bt) {
 526   if (n->Opcode() == Op_Mul(bt) && n->in(2)->is_Con()) {
 527     Node* con = n->in(2);
 528     Node* base = n->in(1);
 529 
 530     if (!con->is_top()) {
 531       return Multiplication(base, con->get_integer_as_long(bt));
 532     }
 533   }
 534 
 535   return make_invalid();
 536 }
 537 
 538 // Try to match `n = (a << CON1) + (a << CON2)`. On success, return a struct with `.valid = true`, `variable = a`, and
 539 // `multiplier = (1 << CON1) + (1 << CON2)`.
 540 // Match `n` for patterns:
 541 //     - (1) (a << CON) + (a << CON)
 542 //     - (2) (a << CON) + a
 543 //     - (3) a + (a << CON)
 544 //     - (4) a + a
 545 // Note that one or both of the term of the addition could simply be `a` (i.e., a << 0) as in pattern (4).
 546 AddNode::Multiplication AddNode::Multiplication::find_power_of_two_addition_pattern(const Node* n, BasicType bt) {
 547   if (n->Opcode() == Op_Add(bt) && n->in(1) != n->in(2)) {
 548     const Multiplication lhs = find_simple_lshift_pattern(n->in(1), bt);
 549     const Multiplication rhs = find_simple_lshift_pattern(n->in(2), bt);
 550 
 551     // Pattern (1)
 552     {
 553       const Multiplication res = lhs.add(rhs);
 554       if (res.is_valid()) {
 555         return res;
 556       }
 557     }
 558 
 559     // Pattern (2)
 560     if (lhs.is_valid_with(n->in(2))) {
 561       return Multiplication(lhs.variable(), java_add(lhs.multiplier(), CONST64(1)));
 562     }
 563 
 564     // Pattern (3)
 565     if (rhs.is_valid_with(n->in(1))) {
 566       return Multiplication(rhs.variable(), java_add(rhs.multiplier(), CONST64(1)));
 567     }
 568 
 569     // Pattern (4), which is equivalent to a simple addition pattern
 570     return find_simple_addition_pattern(n, bt);
 571   }
 572 
 573   return make_invalid();
 574 }
 575 
 576 Node* AddINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 577   Node* in1 = in(1);
 578   Node* in2 = in(2);
 579   int op1 = in1->Opcode();
 580   int op2 = in2->Opcode();
 581 
 582   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 583   // Helps with array allocation math constant folding
 584   // See 4790063:
 585   // Unrestricted transformation is unsafe for some runtime values of 'x'
 586   // ( x ==  0, z == 1, y == -1 ) fails
 587   // ( x == -5, z == 1, y ==  1 ) fails
 588   // Transform works for small z and small negative y when the addition
 589   // (x + (y << z)) does not cross zero.
 590   // Implement support for negative y and (x >= -(y << z))
 591   // Have not observed cases where type information exists to support
 592   // positive y and (x <= -(y << z))
 593   if (op1 == Op_URShiftI && op2 == Op_ConI &&
 594       in1->in(2)->Opcode() == Op_ConI) {
 595     jint z = phase->type(in1->in(2))->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 596     jint y = phase->type(in2)->is_int()->get_con();
 597 
 598     if (z < 5 && -5 < y && y < 0) {
 599       const Type* t_in11 = phase->type(in1->in(1));
 600       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z))) {
 601         Node* a = phase->transform(new AddINode( in1->in(1), phase->intcon(y<<z)));
 602         return new URShiftINode(a, in1->in(2));
 603       }
 604     }
 605   }
 606 
 607   return AddNode::IdealIL(phase, can_reshape, T_INT);
 608 }
 609 
 610 
 611 //------------------------------Identity---------------------------------------
 612 // Fold (x-y)+y  OR  y+(x-y)  into  x
 613 Node* AddINode::Identity(PhaseGVN* phase) {
 614   if (in(1)->Opcode() == Op_SubI && in(1)->in(2) == in(2)) {
 615     return in(1)->in(1);
 616   } else if (in(2)->Opcode() == Op_SubI && in(2)->in(2) == in(1)) {
 617     return in(2)->in(1);
 618   }
 619   return AddNode::Identity(phase);
 620 }
 621 
 622 
 623 //------------------------------add_ring---------------------------------------
 624 // Supplied function returns the sum of the inputs.  Guaranteed never
 625 // to be passed a TOP or BOTTOM type, these are filtered out by
 626 // pre-check.
 627 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 628   const TypeInt *r0 = t0->is_int(); // Handy access
 629   const TypeInt *r1 = t1->is_int();
 630   int lo = java_add(r0->_lo, r1->_lo);
 631   int hi = java_add(r0->_hi, r1->_hi);
 632   if( !(r0->is_con() && r1->is_con()) ) {
 633     // Not both constants, compute approximate result
 634     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 635       lo = min_jint; hi = max_jint; // Underflow on the low side
 636     }
 637     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 638       lo = min_jint; hi = max_jint; // Overflow on the high side
 639     }
 640     if( lo > hi ) {               // Handle overflow
 641       lo = min_jint; hi = max_jint;
 642     }
 643   } else {
 644     // both constants, compute precise result using 'lo' and 'hi'
 645     // Semantics define overflow and underflow for integer addition
 646     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 647   }
 648   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 649 }
 650 
 651 
 652 //=============================================================================
 653 //------------------------------Idealize---------------------------------------
 654 Node* AddLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 655   return AddNode::IdealIL(phase, can_reshape, T_LONG);
 656 }
 657 
 658 
 659 //------------------------------Identity---------------------------------------
 660 // Fold (x-y)+y  OR  y+(x-y)  into  x
 661 Node* AddLNode::Identity(PhaseGVN* phase) {
 662   if (in(1)->Opcode() == Op_SubL && in(1)->in(2) == in(2)) {
 663     return in(1)->in(1);
 664   } else if (in(2)->Opcode() == Op_SubL && in(2)->in(2) == in(1)) {
 665     return in(2)->in(1);
 666   }
 667   return AddNode::Identity(phase);
 668 }
 669 
 670 
 671 //------------------------------add_ring---------------------------------------
 672 // Supplied function returns the sum of the inputs.  Guaranteed never
 673 // to be passed a TOP or BOTTOM type, these are filtered out by
 674 // pre-check.
 675 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 676   const TypeLong *r0 = t0->is_long(); // Handy access
 677   const TypeLong *r1 = t1->is_long();
 678   jlong lo = java_add(r0->_lo, r1->_lo);
 679   jlong hi = java_add(r0->_hi, r1->_hi);
 680   if( !(r0->is_con() && r1->is_con()) ) {
 681     // Not both constants, compute approximate result
 682     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 683       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 684     }
 685     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 686       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 687     }
 688     if( lo > hi ) {               // Handle overflow
 689       lo = min_jlong; hi = max_jlong;
 690     }
 691   } else {
 692     // both constants, compute precise result using 'lo' and 'hi'
 693     // Semantics define overflow and underflow for integer addition
 694     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 695   }
 696   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 697 }
 698 
 699 
 700 //=============================================================================
 701 //------------------------------add_of_identity--------------------------------
 702 // Check for addition of the identity
 703 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 704   // x ADD 0  should return x unless 'x' is a -zero
 705   //
 706   // const Type *zero = add_id();     // The additive identity
 707   // jfloat f1 = t1->getf();
 708   // jfloat f2 = t2->getf();
 709   //
 710   // if( t1->higher_equal( zero ) ) return t2;
 711   // if( t2->higher_equal( zero ) ) return t1;
 712 
 713   return nullptr;
 714 }
 715 
 716 //------------------------------add_ring---------------------------------------
 717 // Supplied function returns the sum of the inputs.
 718 // This also type-checks the inputs for sanity.  Guaranteed never to
 719 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 720 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 721   if (!t0->isa_float_constant() || !t1->isa_float_constant()) {
 722     return bottom_type();
 723   }
 724   return TypeF::make( t0->getf() + t1->getf() );
 725 }
 726 
 727 //------------------------------Ideal------------------------------------------
 728 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 729   // Floating point additions are not associative because of boundary conditions (infinity)
 730   return commute(phase, this) ? this : nullptr;
 731 }
 732 
 733 //=============================================================================
 734 //------------------------------add_of_identity--------------------------------
 735 // Check for addition of the identity
 736 const Type* AddHFNode::add_of_identity(const Type* t1, const Type* t2) const {
 737   return nullptr;
 738 }
 739 
 740 // Supplied function returns the sum of the inputs.
 741 // This also type-checks the inputs for sanity.  Guaranteed never to
 742 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 743 const Type* AddHFNode::add_ring(const Type* t0, const Type* t1) const {
 744   if (!t0->isa_half_float_constant() || !t1->isa_half_float_constant()) {
 745     return bottom_type();
 746   }
 747   return TypeH::make(t0->getf() + t1->getf());
 748 }
 749 
 750 //=============================================================================
 751 //------------------------------add_of_identity--------------------------------
 752 // Check for addition of the identity
 753 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 754   // x ADD 0  should return x unless 'x' is a -zero
 755   //
 756   // const Type *zero = add_id();     // The additive identity
 757   // jfloat f1 = t1->getf();
 758   // jfloat f2 = t2->getf();
 759   //
 760   // if( t1->higher_equal( zero ) ) return t2;
 761   // if( t2->higher_equal( zero ) ) return t1;
 762 
 763   return nullptr;
 764 }
 765 //------------------------------add_ring---------------------------------------
 766 // Supplied function returns the sum of the inputs.
 767 // This also type-checks the inputs for sanity.  Guaranteed never to
 768 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 769 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 770   if (!t0->isa_double_constant() || !t1->isa_double_constant()) {
 771     return bottom_type();
 772   }
 773   return TypeD::make( t0->getd() + t1->getd() );
 774 }
 775 
 776 //------------------------------Ideal------------------------------------------
 777 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 778   // Floating point additions are not associative because of boundary conditions (infinity)
 779   return commute(phase, this) ? this : nullptr;
 780 }
 781 
 782 
 783 //=============================================================================
 784 //------------------------------Identity---------------------------------------
 785 // If one input is a constant 0, return the other input.
 786 Node* AddPNode::Identity(PhaseGVN* phase) {
 787   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 788 }
 789 
 790 //------------------------------Idealize---------------------------------------
 791 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 792   // Bail out if dead inputs
 793   if( phase->type( in(Address) ) == Type::TOP ) return nullptr;
 794 
 795   // If the left input is an add of a constant, flatten the expression tree.
 796   const Node *n = in(Address);
 797   if (n->is_AddP() && n->in(Base) == in(Base)) {
 798     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 799     assert( !addp->in(Address)->is_AddP() ||
 800              addp->in(Address)->as_AddP() != addp,
 801             "dead loop in AddPNode::Ideal" );
 802     // Type of left input's right input
 803     const Type *t = phase->type( addp->in(Offset) );
 804     if( t == Type::TOP ) return nullptr;
 805     const TypeX *t12 = t->is_intptr_t();
 806     if( t12->is_con() ) {       // Left input is an add of a constant?
 807       // If the right input is a constant, combine constants
 808       const Type *temp_t2 = phase->type( in(Offset) );
 809       if( temp_t2 == Type::TOP ) return nullptr;
 810       const TypeX *t2 = temp_t2->is_intptr_t();
 811       Node* address;
 812       Node* offset;
 813       if( t2->is_con() ) {
 814         // The Add of the flattened expression
 815         address = addp->in(Address);
 816         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 817       } else {
 818         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 819         address = phase->transform(new AddPNode(in(Base),addp->in(Address),in(Offset)));
 820         offset  = addp->in(Offset);
 821       }
 822       set_req_X(Address, address, phase);
 823       set_req_X(Offset, offset, phase);
 824       return this;
 825     }
 826   }
 827 
 828   // Raw pointers?
 829   if( in(Base)->bottom_type() == Type::TOP ) {
 830     // If this is a null+long form (from unsafe accesses), switch to a rawptr.
 831     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
 832       Node* offset = in(Offset);
 833       return new CastX2PNode(offset);
 834     }
 835   }
 836 
 837   // If the right is an add of a constant, push the offset down.
 838   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
 839   // The idea is to merge array_base+scaled_index groups together,
 840   // and only have different constant offsets from the same base.
 841   const Node *add = in(Offset);
 842   if( add->Opcode() == Op_AddX && add->in(1) != add ) {
 843     const Type *t22 = phase->type( add->in(2) );
 844     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?
 845       set_req(Address, phase->transform(new AddPNode(in(Base),in(Address),add->in(1))));
 846       set_req_X(Offset, add->in(2), phase); // puts add on igvn worklist if needed
 847       return this;              // Made progress
 848     }
 849   }
 850 
 851   return nullptr;                  // No progress
 852 }
 853 
 854 //------------------------------bottom_type------------------------------------
 855 // Bottom-type is the pointer-type with unknown offset.
 856 const Type *AddPNode::bottom_type() const {
 857   if (in(Address) == nullptr)  return TypePtr::BOTTOM;
 858   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
 859   if( !tp ) return Type::TOP;   // TOP input means TOP output
 860   assert( in(Offset)->Opcode() != Op_ConP, "" );
 861   const Type *t = in(Offset)->bottom_type();
 862   if( t == Type::TOP )
 863     return tp->add_offset(Type::OffsetTop);
 864   const TypeX *tx = t->is_intptr_t();
 865   intptr_t txoffset = Type::OffsetBot;
 866   if (tx->is_con()) {   // Left input is an add of a constant?
 867     txoffset = tx->get_con();
 868   }
 869   if (tp->isa_aryptr()) {
 870     // In the case of a flat inline type array, each field has its
 871     // own slice so we need to extract the field being accessed from
 872     // the address computation
 873     return tp->is_aryptr()->add_field_offset_and_offset(txoffset);
 874   }
 875   return tp->add_offset(txoffset);
 876 }
 877 
 878 //------------------------------Value------------------------------------------
 879 const Type* AddPNode::Value(PhaseGVN* phase) const {
 880   // Either input is TOP ==> the result is TOP
 881   const Type *t1 = phase->type( in(Address) );
 882   const Type *t2 = phase->type( in(Offset) );
 883   if( t1 == Type::TOP ) return Type::TOP;
 884   if( t2 == Type::TOP ) return Type::TOP;
 885 
 886   // Left input is a pointer
 887   const TypePtr *p1 = t1->isa_ptr();
 888   // Right input is an int
 889   const TypeX *p2 = t2->is_intptr_t();
 890   // Add 'em
 891   intptr_t p2offset = Type::OffsetBot;
 892   if (p2->is_con()) {   // Left input is an add of a constant?
 893     p2offset = p2->get_con();
 894   }
 895   if (p1->isa_aryptr()) {
 896     // In the case of a flat inline type array, each field has its
 897     // own slice so we need to extract the field being accessed from
 898     // the address computation
 899     return p1->is_aryptr()->add_field_offset_and_offset(p2offset);
 900   }
 901   return p1->add_offset(p2offset);
 902 }
 903 
 904 //------------------------Ideal_base_and_offset--------------------------------
 905 // Split an oop pointer into a base and offset.
 906 // (The offset might be Type::OffsetBot in the case of an array.)
 907 // Return the base, or null if failure.
 908 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseValues* phase,
 909                                       // second return value:
 910                                       intptr_t& offset) {
 911   if (ptr->is_AddP()) {
 912     Node* base = ptr->in(AddPNode::Base);
 913     Node* addr = ptr->in(AddPNode::Address);
 914     Node* offs = ptr->in(AddPNode::Offset);
 915     if (base == addr || base->is_top()) {
 916       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 917       if (offset != Type::OffsetBot) {
 918         return addr;
 919       }
 920     }
 921   }
 922   offset = Type::OffsetBot;
 923   return nullptr;
 924 }
 925 
 926 //------------------------------unpack_offsets----------------------------------
 927 // Collect the AddP offset values into the elements array, giving up
 928 // if there are more than length.
 929 int AddPNode::unpack_offsets(Node* elements[], int length) const {
 930   int count = 0;
 931   Node const* addr = this;
 932   Node* base = addr->in(AddPNode::Base);
 933   while (addr->is_AddP()) {
 934     if (addr->in(AddPNode::Base) != base) {
 935       // give up
 936       return -1;
 937     }
 938     elements[count++] = addr->in(AddPNode::Offset);
 939     if (count == length) {
 940       // give up
 941       return -1;
 942     }
 943     addr = addr->in(AddPNode::Address);
 944   }
 945   if (addr != base) {
 946     return -1;
 947   }
 948   return count;
 949 }
 950 
 951 //------------------------------match_edge-------------------------------------
 952 // Do we Match on this edge index or not?  Do not match base pointer edge
 953 uint AddPNode::match_edge(uint idx) const {
 954   return idx > Base;
 955 }
 956 
 957 //=============================================================================
 958 //------------------------------Identity---------------------------------------
 959 Node* OrINode::Identity(PhaseGVN* phase) {
 960   // x | x => x
 961   if (in(1) == in(2)) {
 962     return in(1);
 963   }
 964 
 965   return AddNode::Identity(phase);
 966 }
 967 
 968 // Find shift value for Integer or Long OR.
 969 static Node* rotate_shift(PhaseGVN* phase, Node* lshift, Node* rshift, int mask) {
 970   // val << norm_con_shift | val >> ({32|64} - norm_con_shift) => rotate_left val, norm_con_shift
 971   const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 972   const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 973   if (lshift_t != nullptr && lshift_t->is_con() &&
 974       rshift_t != nullptr && rshift_t->is_con() &&
 975       ((lshift_t->get_con() & mask) == ((mask + 1) - (rshift_t->get_con() & mask)))) {
 976     return phase->intcon(lshift_t->get_con() & mask);
 977   }
 978   // val << var_shift | val >> ({0|32|64} - var_shift) => rotate_left val, var_shift
 979   if (rshift->Opcode() == Op_SubI && rshift->in(2) == lshift && rshift->in(1)->is_Con()){
 980     const TypeInt* shift_t = phase->type(rshift->in(1))->isa_int();
 981     if (shift_t != nullptr && shift_t->is_con() &&
 982         (shift_t->get_con() == 0 || shift_t->get_con() == (mask + 1))) {
 983       return lshift;
 984     }
 985   }
 986   return nullptr;
 987 }
 988 
 989 Node* OrINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 990   int lopcode = in(1)->Opcode();
 991   int ropcode = in(2)->Opcode();
 992   if (Matcher::match_rule_supported(Op_RotateLeft) &&
 993       lopcode == Op_LShiftI && ropcode == Op_URShiftI && in(1)->in(1) == in(2)->in(1)) {
 994     Node* lshift = in(1)->in(2);
 995     Node* rshift = in(2)->in(2);
 996     Node* shift = rotate_shift(phase, lshift, rshift, 0x1F);
 997     if (shift != nullptr) {
 998       return new RotateLeftNode(in(1)->in(1), shift, TypeInt::INT);
 999     }
1000     return nullptr;
1001   }
1002   if (Matcher::match_rule_supported(Op_RotateRight) &&
1003       lopcode == Op_URShiftI && ropcode == Op_LShiftI && in(1)->in(1) == in(2)->in(1)) {
1004     Node* rshift = in(1)->in(2);
1005     Node* lshift = in(2)->in(2);
1006     Node* shift = rotate_shift(phase, rshift, lshift, 0x1F);
1007     if (shift != nullptr) {
1008       return new RotateRightNode(in(1)->in(1), shift, TypeInt::INT);
1009     }
1010   }
1011 
1012   // Convert "~a | ~b" into "~(a & b)"
1013   if (AddNode::is_not(phase, in(1), T_INT) && AddNode::is_not(phase, in(2), T_INT)) {
1014     Node* and_a_b = new AndINode(in(1)->in(1), in(2)->in(1));
1015     Node* tn = phase->transform(and_a_b);
1016     return AddNode::make_not(phase, tn, T_INT);
1017   }
1018   return AddNode::Ideal(phase, can_reshape);
1019 }
1020 
1021 //------------------------------add_ring---------------------------------------
1022 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
1023 // the logical operations the ring's ADD is really a logical OR function.
1024 // This also type-checks the inputs for sanity.  Guaranteed never to
1025 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
1026 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
1027   const TypeInt *r0 = t0->is_int(); // Handy access
1028   const TypeInt *r1 = t1->is_int();
1029 
1030   // If both args are bool, can figure out better types
1031   if ( r0 == TypeInt::BOOL ) {
1032     if ( r1 == TypeInt::ONE) {
1033       return TypeInt::ONE;
1034     } else if ( r1 == TypeInt::BOOL ) {
1035       return TypeInt::BOOL;
1036     }
1037   } else if ( r0 == TypeInt::ONE ) {
1038     if ( r1 == TypeInt::BOOL ) {
1039       return TypeInt::ONE;
1040     }
1041   }
1042 
1043   // If either input is all ones, the output is all ones.
1044   // x | ~0 == ~0 <==> x | -1 == -1
1045   if (r0 == TypeInt::MINUS_1 || r1 == TypeInt::MINUS_1) {
1046     return TypeInt::MINUS_1;
1047   }
1048 
1049   // If either input is not a constant, just return all integers.
1050   if( !r0->is_con() || !r1->is_con() )
1051     return TypeInt::INT;        // Any integer, but still no symbols.
1052 
1053   // Otherwise just OR them bits.
1054   return TypeInt::make( r0->get_con() | r1->get_con() );
1055 }
1056 
1057 //=============================================================================
1058 //------------------------------Identity---------------------------------------
1059 Node* OrLNode::Identity(PhaseGVN* phase) {
1060   // x | x => x
1061   if (in(1) == in(2)) {
1062     return in(1);
1063   }
1064 
1065   return AddNode::Identity(phase);
1066 }
1067 
1068 Node* OrLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1069   int lopcode = in(1)->Opcode();
1070   int ropcode = in(2)->Opcode();
1071   if (Matcher::match_rule_supported(Op_RotateLeft) &&
1072       lopcode == Op_LShiftL && ropcode == Op_URShiftL && in(1)->in(1) == in(2)->in(1)) {
1073     Node* lshift = in(1)->in(2);
1074     Node* rshift = in(2)->in(2);
1075     Node* shift = rotate_shift(phase, lshift, rshift, 0x3F);
1076     if (shift != nullptr) {
1077       return new RotateLeftNode(in(1)->in(1), shift, TypeLong::LONG);
1078     }
1079     return nullptr;
1080   }
1081   if (Matcher::match_rule_supported(Op_RotateRight) &&
1082       lopcode == Op_URShiftL && ropcode == Op_LShiftL && in(1)->in(1) == in(2)->in(1)) {
1083     Node* rshift = in(1)->in(2);
1084     Node* lshift = in(2)->in(2);
1085     Node* shift = rotate_shift(phase, rshift, lshift, 0x3F);
1086     if (shift != nullptr) {
1087       return new RotateRightNode(in(1)->in(1), shift, TypeLong::LONG);
1088     }
1089   }
1090 
1091   // Convert "~a | ~b" into "~(a & b)"
1092   if (AddNode::is_not(phase, in(1), T_LONG) && AddNode::is_not(phase, in(2), T_LONG)) {
1093     Node* and_a_b = new AndLNode(in(1)->in(1), in(2)->in(1));
1094     Node* tn = phase->transform(and_a_b);
1095     return AddNode::make_not(phase, tn, T_LONG);
1096   }
1097 
1098   return AddNode::Ideal(phase, can_reshape);
1099 }
1100 
1101 //------------------------------add_ring---------------------------------------
1102 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
1103   const TypeLong *r0 = t0->is_long(); // Handy access
1104   const TypeLong *r1 = t1->is_long();
1105 
1106   // If either input is all ones, the output is all ones.
1107   // x | ~0 == ~0 <==> x | -1 == -1
1108   if (r0 == TypeLong::MINUS_1 || r1 == TypeLong::MINUS_1) {
1109     return TypeLong::MINUS_1;
1110   }
1111 
1112   // If either input is not a constant, just return all integers.
1113   if( !r0->is_con() || !r1->is_con() )
1114     return TypeLong::LONG;      // Any integer, but still no symbols.
1115 
1116   // Otherwise just OR them bits.
1117   return TypeLong::make( r0->get_con() | r1->get_con() );
1118 }
1119 
1120 //---------------------------Helper -------------------------------------------
1121 /* Decide if the given node is used only in arithmetic expressions(add or sub).
1122  */
1123 static bool is_used_in_only_arithmetic(Node* n, BasicType bt) {
1124   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1125     Node* u = n->fast_out(i);
1126     if (u->Opcode() != Op_Add(bt) && u->Opcode() != Op_Sub(bt)) {
1127       return false;
1128     }
1129   }
1130   return true;
1131 }
1132 
1133 //=============================================================================
1134 //------------------------------Idealize---------------------------------------
1135 Node* XorINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1136   Node* in1 = in(1);
1137   Node* in2 = in(2);
1138 
1139   // Convert ~x into -1-x when ~x is used in an arithmetic expression
1140   // or x itself is an expression.
1141   if (phase->type(in2) == TypeInt::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
1142     if (phase->is_IterGVN()) {
1143       if (is_used_in_only_arithmetic(this, T_INT)
1144           // LHS is arithmetic
1145           || (in1->Opcode() == Op_AddI || in1->Opcode() == Op_SubI)) {
1146         return new SubINode(in2, in1);
1147       }
1148     } else {
1149       // graph could be incomplete in GVN so we postpone to IGVN
1150       phase->record_for_igvn(this);
1151     }
1152   }
1153 
1154   // Propagate xor through constant cmoves. This pattern can occur after expansion of Conv2B nodes.
1155   const TypeInt* in2_type = phase->type(in2)->isa_int();
1156   if (in1->Opcode() == Op_CMoveI && in2_type != nullptr && in2_type->is_con()) {
1157     int in2_val = in2_type->get_con();
1158 
1159     // Get types of both sides of the CMove
1160     const TypeInt* left = phase->type(in1->in(CMoveNode::IfFalse))->isa_int();
1161     const TypeInt* right = phase->type(in1->in(CMoveNode::IfTrue))->isa_int();
1162 
1163     // Ensure that both sides are int constants
1164     if (left != nullptr && right != nullptr && left->is_con() && right->is_con()) {
1165       Node* cond = in1->in(CMoveNode::Condition);
1166 
1167       // Check that the comparison is a bool and that the cmp node type is correct
1168       if (cond->is_Bool()) {
1169         int cmp_op = cond->in(1)->Opcode();
1170 
1171         if (cmp_op == Op_CmpI || cmp_op == Op_CmpP) {
1172           int l_val = left->get_con();
1173           int r_val = right->get_con();
1174 
1175           return new CMoveINode(cond, phase->intcon(l_val ^ in2_val), phase->intcon(r_val ^ in2_val), TypeInt::INT);
1176         }
1177       }
1178     }
1179   }
1180 
1181   return AddNode::Ideal(phase, can_reshape);
1182 }
1183 
1184 const Type* XorINode::Value(PhaseGVN* phase) const {
1185   Node* in1 = in(1);
1186   Node* in2 = in(2);
1187   const Type* t1 = phase->type(in1);
1188   const Type* t2 = phase->type(in2);
1189   if (t1 == Type::TOP || t2 == Type::TOP) {
1190     return Type::TOP;
1191   }
1192   // x ^ x ==> 0
1193   if (in1->eqv_uncast(in2)) {
1194     return add_id();
1195   }
1196   return AddNode::Value(phase);
1197 }
1198 
1199 //------------------------------add_ring---------------------------------------
1200 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
1201 // the logical operations the ring's ADD is really a logical OR function.
1202 // This also type-checks the inputs for sanity.  Guaranteed never to
1203 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
1204 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
1205   const TypeInt *r0 = t0->is_int(); // Handy access
1206   const TypeInt *r1 = t1->is_int();
1207 
1208   if (r0->is_con() && r1->is_con()) {
1209     // compute constant result
1210     return TypeInt::make(r0->get_con() ^ r1->get_con());
1211   }
1212 
1213   // At least one of the arguments is not constant
1214 
1215   if (r0->_lo >= 0 && r1->_lo >= 0) {
1216       // Combine [r0->_lo, r0->_hi] ^ [r0->_lo, r1->_hi] -> [0, upper_bound]
1217       jint upper_bound = xor_upper_bound_for_ranges<jint, juint>(r0->_hi, r1->_hi);
1218       return TypeInt::make(0, upper_bound, MAX2(r0->_widen, r1->_widen));
1219   }
1220 
1221   return TypeInt::INT;
1222 }
1223 
1224 //=============================================================================
1225 //------------------------------add_ring---------------------------------------
1226 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
1227   const TypeLong *r0 = t0->is_long(); // Handy access
1228   const TypeLong *r1 = t1->is_long();
1229 
1230   if (r0->is_con() && r1->is_con()) {
1231     // compute constant result
1232     return TypeLong::make(r0->get_con() ^ r1->get_con());
1233   }
1234 
1235   // At least one of the arguments is not constant
1236 
1237   if (r0->_lo >= 0 && r1->_lo >= 0) {
1238       // Combine [r0->_lo, r0->_hi] ^ [r0->_lo, r1->_hi] -> [0, upper_bound]
1239       julong upper_bound = xor_upper_bound_for_ranges<jlong, julong>(r0->_hi, r1->_hi);
1240       return TypeLong::make(0, upper_bound, MAX2(r0->_widen, r1->_widen));
1241   }
1242 
1243   return TypeLong::LONG;
1244 }
1245 
1246 Node* XorLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1247   Node* in1 = in(1);
1248   Node* in2 = in(2);
1249 
1250   // Convert ~x into -1-x when ~x is used in an arithmetic expression
1251   // or x itself is an arithmetic expression.
1252   if (phase->type(in2) == TypeLong::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
1253     if (phase->is_IterGVN()) {
1254       if (is_used_in_only_arithmetic(this, T_LONG)
1255           // LHS is arithmetic
1256           || (in1->Opcode() == Op_AddL || in1->Opcode() == Op_SubL)) {
1257         return new SubLNode(in2, in1);
1258       }
1259     } else {
1260       // graph could be incomplete in GVN so we postpone to IGVN
1261       phase->record_for_igvn(this);
1262     }
1263   }
1264   return AddNode::Ideal(phase, can_reshape);
1265 }
1266 
1267 const Type* XorLNode::Value(PhaseGVN* phase) const {
1268   Node* in1 = in(1);
1269   Node* in2 = in(2);
1270   const Type* t1 = phase->type(in1);
1271   const Type* t2 = phase->type(in2);
1272   if (t1 == Type::TOP || t2 == Type::TOP) {
1273     return Type::TOP;
1274   }
1275   // x ^ x ==> 0
1276   if (in1->eqv_uncast(in2)) {
1277     return add_id();
1278   }
1279 
1280   return AddNode::Value(phase);
1281 }
1282 
1283 Node* MaxNode::build_min_max_int(Node* a, Node* b, bool is_max) {
1284   if (is_max) {
1285     return new MaxINode(a, b);
1286   } else {
1287     return new MinINode(a, b);
1288   }
1289 }
1290 
1291 Node* MaxNode::build_min_max_long(PhaseGVN* phase, Node* a, Node* b, bool is_max) {
1292   if (is_max) {
1293     return new MaxLNode(phase->C, a, b);
1294   } else {
1295     return new MinLNode(phase->C, a, b);
1296   }
1297 }
1298 
1299 Node* MaxNode::build_min_max(Node* a, Node* b, bool is_max, bool is_unsigned, const Type* t, PhaseGVN& gvn) {
1300   bool is_int = gvn.type(a)->isa_int();
1301   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1302   assert(is_int == (gvn.type(b)->isa_int() != nullptr), "inconsistent inputs");
1303   BasicType bt = is_int ? T_INT: T_LONG;
1304   Node* hook = nullptr;
1305   if (gvn.is_IterGVN()) {
1306     // Make sure a and b are not destroyed
1307     hook = new Node(2);
1308     hook->init_req(0, a);
1309     hook->init_req(1, b);
1310   }
1311   Node* res = nullptr;
1312   if (is_int && !is_unsigned) {
1313     res = gvn.transform(build_min_max_int(a, b, is_max));
1314     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");
1315   } else {
1316     Node* cmp = nullptr;
1317     if (is_max) {
1318       cmp = gvn.transform(CmpNode::make(a, b, bt, is_unsigned));
1319     } else {
1320       cmp = gvn.transform(CmpNode::make(b, a, bt, is_unsigned));
1321     }
1322     Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1323     res = gvn.transform(CMoveNode::make(bol, a, b, t));
1324   }
1325   if (hook != nullptr) {
1326     hook->destruct(&gvn);
1327   }
1328   return res;
1329 }
1330 
1331 Node* MaxNode::build_min_max_diff_with_zero(Node* a, Node* b, bool is_max, const Type* t, PhaseGVN& gvn) {
1332   bool is_int = gvn.type(a)->isa_int();
1333   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1334   assert(is_int == (gvn.type(b)->isa_int() != nullptr), "inconsistent inputs");
1335   BasicType bt = is_int ? T_INT: T_LONG;
1336   Node* zero = gvn.integercon(0, bt);
1337   Node* hook = nullptr;
1338   if (gvn.is_IterGVN()) {
1339     // Make sure a and b are not destroyed
1340     hook = new Node(2);
1341     hook->init_req(0, a);
1342     hook->init_req(1, b);
1343   }
1344   Node* cmp = nullptr;
1345   if (is_max) {
1346     cmp = gvn.transform(CmpNode::make(a, b, bt, false));
1347   } else {
1348     cmp = gvn.transform(CmpNode::make(b, a, bt, false));
1349   }
1350   Node* sub = gvn.transform(SubNode::make(a, b, bt));
1351   Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1352   Node* res = gvn.transform(CMoveNode::make(bol, sub, zero, t));
1353   if (hook != nullptr) {
1354     hook->destruct(&gvn);
1355   }
1356   return res;
1357 }
1358 
1359 // Check if addition of an integer with type 't' and a constant 'c' can overflow.
1360 static bool can_overflow(const TypeInt* t, jint c) {
1361   jint t_lo = t->_lo;
1362   jint t_hi = t->_hi;
1363   return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
1364           (c > 0 && (java_add(t_hi, c) < t_hi)));
1365 }
1366 
1367 // Check if addition of a long with type 't' and a constant 'c' can overflow.
1368 static bool can_overflow(const TypeLong* t, jlong c) {
1369   jlong t_lo = t->_lo;
1370   jlong t_hi = t->_hi;
1371   return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
1372           (c > 0 && (java_add(t_hi, c) < t_hi)));
1373 }
1374 
1375 // Let <x, x_off> = x_operands and <y, y_off> = y_operands.
1376 // If x == y and neither add(x, x_off) nor add(y, y_off) overflow, return
1377 // add(x, op(x_off, y_off)). Otherwise, return nullptr.
1378 Node* MaxNode::extract_add(PhaseGVN* phase, ConstAddOperands x_operands, ConstAddOperands y_operands) {
1379   Node* x = x_operands.first;
1380   Node* y = y_operands.first;
1381   int opcode = Opcode();
1382   assert(opcode == Op_MaxI || opcode == Op_MinI, "Unexpected opcode");
1383   const TypeInt* tx = phase->type(x)->isa_int();
1384   jint x_off = x_operands.second;
1385   jint y_off = y_operands.second;
1386   if (x == y && tx != nullptr &&
1387       !can_overflow(tx, x_off) &&
1388       !can_overflow(tx, y_off)) {
1389     jint c = opcode == Op_MinI ? MIN2(x_off, y_off) : MAX2(x_off, y_off);
1390     return new AddINode(x, phase->intcon(c));
1391   }
1392   return nullptr;
1393 }
1394 
1395 // Try to cast n as an integer addition with a constant. Return:
1396 //   <x, C>,       if n == add(x, C), where 'C' is a non-TOP constant;
1397 //   <nullptr, 0>, if n == add(x, C), where 'C' is a TOP constant; or
1398 //   <n, 0>,       otherwise.
1399 static ConstAddOperands as_add_with_constant(Node* n) {
1400   if (n->Opcode() != Op_AddI) {
1401     return ConstAddOperands(n, 0);
1402   }
1403   Node* x = n->in(1);
1404   Node* c = n->in(2);
1405   if (!c->is_Con()) {
1406     return ConstAddOperands(n, 0);
1407   }
1408   const Type* c_type = c->bottom_type();
1409   if (c_type == Type::TOP) {
1410     return ConstAddOperands(nullptr, 0);
1411   }
1412   return ConstAddOperands(x, c_type->is_int()->get_con());
1413 }
1414 
1415 Node* MaxNode::IdealI(PhaseGVN* phase, bool can_reshape) {
1416   int opcode = Opcode();
1417   assert(opcode == Op_MinI || opcode == Op_MaxI, "Unexpected opcode");
1418   // Try to transform the following pattern, in any of its four possible
1419   // permutations induced by op's commutativity:
1420   //     op(op(add(inner, inner_off), inner_other), add(outer, outer_off))
1421   // into
1422   //     op(add(inner, op(inner_off, outer_off)), inner_other),
1423   // where:
1424   //     op is either MinI or MaxI, and
1425   //     inner == outer, and
1426   //     the additions cannot overflow.
1427   for (uint inner_op_index = 1; inner_op_index <= 2; inner_op_index++) {
1428     if (in(inner_op_index)->Opcode() != opcode) {
1429       continue;
1430     }
1431     Node* outer_add = in(inner_op_index == 1 ? 2 : 1);
1432     ConstAddOperands outer_add_operands = as_add_with_constant(outer_add);
1433     if (outer_add_operands.first == nullptr) {
1434       return nullptr; // outer_add has a TOP input, no need to continue.
1435     }
1436     // One operand is a MinI/MaxI and the other is an integer addition with
1437     // constant. Test the operands of the inner MinI/MaxI.
1438     for (uint inner_add_index = 1; inner_add_index <= 2; inner_add_index++) {
1439       Node* inner_op = in(inner_op_index);
1440       Node* inner_add = inner_op->in(inner_add_index);
1441       ConstAddOperands inner_add_operands = as_add_with_constant(inner_add);
1442       if (inner_add_operands.first == nullptr) {
1443         return nullptr; // inner_add has a TOP input, no need to continue.
1444       }
1445       // Try to extract the inner add.
1446       Node* add_extracted = extract_add(phase, inner_add_operands, outer_add_operands);
1447       if (add_extracted == nullptr) {
1448         continue;
1449       }
1450       Node* add_transformed = phase->transform(add_extracted);
1451       Node* inner_other = inner_op->in(inner_add_index == 1 ? 2 : 1);
1452       return build_min_max_int(add_transformed, inner_other, opcode == Op_MaxI);
1453     }
1454   }
1455   // Try to transform
1456   //     op(add(x, x_off), add(y, y_off))
1457   // into
1458   //     add(x, op(x_off, y_off)),
1459   // where:
1460   //     op is either MinI or MaxI, and
1461   //     inner == outer, and
1462   //     the additions cannot overflow.
1463   ConstAddOperands xC = as_add_with_constant(in(1));
1464   ConstAddOperands yC = as_add_with_constant(in(2));
1465   if (xC.first == nullptr || yC.first == nullptr) return nullptr;
1466   return extract_add(phase, xC, yC);
1467 }
1468 
1469 // Ideal transformations for MaxINode
1470 Node* MaxINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1471   return IdealI(phase, can_reshape);
1472 }
1473 
1474 Node* MaxINode::Identity(PhaseGVN* phase) {
1475   const TypeInt* t1 = phase->type(in(1))->is_int();
1476   const TypeInt* t2 = phase->type(in(2))->is_int();
1477 
1478   // Can we determine the maximum statically?
1479   if (t1->_lo >= t2->_hi) {
1480     return in(1);
1481   } else if (t2->_lo >= t1->_hi) {
1482     return in(2);
1483   }
1484 
1485   return MaxNode::Identity(phase);
1486 }
1487 
1488 //=============================================================================
1489 //------------------------------add_ring---------------------------------------
1490 // Supplied function returns the sum of the inputs.
1491 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
1492   const TypeInt *r0 = t0->is_int(); // Handy access
1493   const TypeInt *r1 = t1->is_int();
1494 
1495   // Otherwise just MAX them bits.
1496   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1497 }
1498 
1499 //=============================================================================
1500 //------------------------------Idealize---------------------------------------
1501 // MINs show up in range-check loop limit calculations.  Look for
1502 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
1503 Node* MinINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1504   return IdealI(phase, can_reshape);
1505 }
1506 
1507 Node* MinINode::Identity(PhaseGVN* phase) {
1508   const TypeInt* t1 = phase->type(in(1))->is_int();
1509   const TypeInt* t2 = phase->type(in(2))->is_int();
1510 
1511   // Can we determine the minimum statically?
1512   if (t1->_lo >= t2->_hi) {
1513     return in(2);
1514   } else if (t2->_lo >= t1->_hi) {
1515     return in(1);
1516   }
1517 
1518   return MaxNode::Identity(phase);
1519 }
1520 
1521 //------------------------------add_ring---------------------------------------
1522 // Supplied function returns the sum of the inputs.
1523 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
1524   const TypeInt *r0 = t0->is_int(); // Handy access
1525   const TypeInt *r1 = t1->is_int();
1526 
1527   // Otherwise just MIN them bits.
1528   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1529 }
1530 
1531 // Collapse the "addition with overflow-protection" pattern, and the symmetrical
1532 // "subtraction with underflow-protection" pattern. These are created during the
1533 // unrolling, when we have to adjust the limit by subtracting the stride, but want
1534 // to protect against underflow: MaxL(SubL(limit, stride), min_jint).
1535 // If we have more than one of those in a sequence:
1536 //
1537 //   x  con2
1538 //   |  |
1539 //   AddL  clamp2
1540 //     |    |
1541 //    Max/MinL con1
1542 //          |  |
1543 //          AddL  clamp1
1544 //            |    |
1545 //           Max/MinL (n)
1546 //
1547 // We want to collapse it to:
1548 //
1549 //   x  con1  con2
1550 //   |    |    |
1551 //   |   AddLNode (new_con)
1552 //   |    |
1553 //  AddLNode  clamp1
1554 //        |    |
1555 //       Max/MinL (n)
1556 //
1557 // Note: we assume that SubL was already replaced by an AddL, and that the stride
1558 // has its sign flipped: SubL(limit, stride) -> AddL(limit, -stride).
1559 //
1560 // Proof MaxL collapsed version equivalent to original (MinL version similar):
1561 // is_sub_con ensures that con1, con2 ∈ [min_int, 0[
1562 //
1563 // Original:
1564 // - AddL2 underflow => x + con2 ∈ ]max_long - min_int, max_long], ALWAYS BAILOUT as x + con1 + con2 surely fails can_overflow (*)
1565 // - AddL2 no underflow => x + con2 ∈ [min_long, max_long]
1566 //   - MaxL2 clamp => min_int
1567 //     - AddL1 underflow: NOT POSSIBLE: cannot underflow since min_int + con1 ∈ [2 * min_int, min_int] always > min_long
1568 //     - AddL1 no underflow => min_int + con1 ∈ [2 * min_int, min_int]
1569 //       - MaxL1 clamp => min_int (RESULT 1)
1570 //       - MaxL1 no clamp: NOT POSSIBLE: min_int + con1 ∈ [2 * min_int, min_int] always <= min_int, so clamp always taken
1571 //   - MaxL2 no clamp => x + con2 ∈ [min_int, max_long]
1572 //     - AddL1 underflow: NOT POSSIBLE: cannot underflow since x + con2 + con1 ∈ [2 * min_int, max_long] always > min_long
1573 //     - AddL1 no underflow => x + con2 + con1 ∈ [2 * min_int, max_long]
1574 //       - MaxL1 clamp => min_int (RESULT 2)
1575 //       - MaxL1 no clamp => x + con2 + con1 ∈ ]min_int, max_long] (RESULT 3)
1576 //
1577 // Collapsed:
1578 // - AddL2 (cannot underflow) => con2 + con1 ∈ [2 * min_int, 0]
1579 //   - AddL1 underflow: NOT POSSIBLE: would have bailed out at can_overflow (*)
1580 //   - AddL1 no underflow => x + con2 + con1 ∈ [min_long, max_long]
1581 //     - MaxL clamp => min_int (RESULT 1 and RESULT 2)
1582 //     - MaxL no clamp => x + con2 + con1 ∈ ]min_int, max_long] (RESULT 3)
1583 //
1584 static Node* fold_subI_no_underflow_pattern(Node* n, PhaseGVN* phase) {
1585   assert(n->Opcode() == Op_MaxL || n->Opcode() == Op_MinL, "sanity");
1586   // Check that the two clamps have the correct values.
1587   jlong clamp = (n->Opcode() == Op_MaxL) ? min_jint : max_jint;
1588   auto is_clamp = [&](Node* c) {
1589     const TypeLong* t = phase->type(c)->isa_long();
1590     return t != nullptr && t->is_con() &&
1591            t->get_con() == clamp;
1592   };
1593   // Check that the constants are negative if MaxL, and positive if MinL.
1594   auto is_sub_con = [&](Node* c) {
1595     const TypeLong* t = phase->type(c)->isa_long();
1596     return t != nullptr && t->is_con() &&
1597            t->get_con() < max_jint && t->get_con() > min_jint &&
1598            (t->get_con() < 0) == (n->Opcode() == Op_MaxL);
1599   };
1600   // Verify the graph level by level:
1601   Node* add1   = n->in(1);
1602   Node* clamp1 = n->in(2);
1603   if (add1->Opcode() == Op_AddL && is_clamp(clamp1)) {
1604     Node* max2 = add1->in(1);
1605     Node* con1 = add1->in(2);
1606     if (max2->Opcode() == n->Opcode() && is_sub_con(con1)) {
1607       Node* add2   = max2->in(1);
1608       Node* clamp2 = max2->in(2);
1609       if (add2->Opcode() == Op_AddL && is_clamp(clamp2)) {
1610         Node* x    = add2->in(1);
1611         Node* con2 = add2->in(2);
1612         if (is_sub_con(con2)) {
1613           // Collapsed graph not equivalent if potential over/underflow -> bailing out (*)
1614           if (can_overflow(phase->type(x)->is_long(), con1->get_long() + con2->get_long())) {
1615             return nullptr;
1616           }
1617           Node* new_con = phase->transform(new AddLNode(con1, con2));
1618           Node* new_sub = phase->transform(new AddLNode(x, new_con));
1619           n->set_req_X(1, new_sub, phase);
1620           return n;
1621         }
1622       }
1623     }
1624   }
1625   return nullptr;
1626 }
1627 
1628 const Type* MaxLNode::add_ring(const Type* t0, const Type* t1) const {
1629   const TypeLong* r0 = t0->is_long();
1630   const TypeLong* r1 = t1->is_long();
1631 
1632   return TypeLong::make(MAX2(r0->_lo, r1->_lo), MAX2(r0->_hi, r1->_hi), MAX2(r0->_widen, r1->_widen));
1633 }
1634 
1635 Node* MaxLNode::Identity(PhaseGVN* phase) {
1636   const TypeLong* t1 = phase->type(in(1))->is_long();
1637   const TypeLong* t2 = phase->type(in(2))->is_long();
1638 
1639   // Can we determine maximum statically?
1640   if (t1->_lo >= t2->_hi) {
1641     return in(1);
1642   } else if (t2->_lo >= t1->_hi) {
1643     return in(2);
1644   }
1645 
1646   return MaxNode::Identity(phase);
1647 }
1648 
1649 Node* MaxLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1650   Node* n = AddNode::Ideal(phase, can_reshape);
1651   if (n != nullptr) {
1652     return n;
1653   }
1654   if (can_reshape) {
1655     return fold_subI_no_underflow_pattern(this, phase);
1656   }
1657   return nullptr;
1658 }
1659 
1660 const Type* MinLNode::add_ring(const Type* t0, const Type* t1) const {
1661   const TypeLong* r0 = t0->is_long();
1662   const TypeLong* r1 = t1->is_long();
1663 
1664   return TypeLong::make(MIN2(r0->_lo, r1->_lo), MIN2(r0->_hi, r1->_hi), MAX2(r0->_widen, r1->_widen));
1665 }
1666 
1667 Node* MinLNode::Identity(PhaseGVN* phase) {
1668   const TypeLong* t1 = phase->type(in(1))->is_long();
1669   const TypeLong* t2 = phase->type(in(2))->is_long();
1670 
1671   // Can we determine minimum statically?
1672   if (t1->_lo >= t2->_hi) {
1673     return in(2);
1674   } else if (t2->_lo >= t1->_hi) {
1675     return in(1);
1676   }
1677 
1678   return MaxNode::Identity(phase);
1679 }
1680 
1681 Node* MinLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
1682   Node* n = AddNode::Ideal(phase, can_reshape);
1683   if (n != nullptr) {
1684     return n;
1685   }
1686   if (can_reshape) {
1687     return fold_subI_no_underflow_pattern(this, phase);
1688   }
1689   return nullptr;
1690 }
1691 
1692 int MaxNode::opposite_opcode() const {
1693   if (Opcode() == max_opcode()) {
1694     return min_opcode();
1695   } else {
1696     assert(Opcode() == min_opcode(), "Caller should be either %s or %s, but is %s", NodeClassNames[max_opcode()], NodeClassNames[min_opcode()], NodeClassNames[Opcode()]);
1697     return max_opcode();
1698   }
1699 }
1700 
1701 // 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.
1702 // '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.
1703 Node* MaxNode::find_identity_operation(Node* operation, Node* operand) {
1704   if (operation->Opcode() == Opcode() || operation->Opcode() == opposite_opcode()) {
1705     Node* n1 = operation->in(1);
1706     Node* n2 = operation->in(2);
1707 
1708     // Given Op(A, Op(B, C)), see if either A == B or A == C is true.
1709     if (n1 == operand || n2 == operand) {
1710       // If the operations are the same return the inner operation, as Max(A, Max(A, B)) == Max(A, B).
1711       if (operation->Opcode() == Opcode()) {
1712         return operation;
1713       }
1714 
1715       // If the operations are different return the operand 'A', as Max(A, Min(A, B)) == A if the value isn't floating point.
1716       // With floating point values, the identity doesn't hold if B == NaN.
1717       const Type* type = bottom_type();
1718       if (type->isa_int() || type->isa_long()) {
1719         return operand;
1720       }
1721     }
1722   }
1723 
1724   return nullptr;
1725 }
1726 
1727 Node* MaxNode::Identity(PhaseGVN* phase) {
1728   if (in(1) == in(2)) {
1729       return in(1);
1730   }
1731 
1732   Node* identity_1 = MaxNode::find_identity_operation(in(2), in(1));
1733   if (identity_1 != nullptr) {
1734     return identity_1;
1735   }
1736 
1737   Node* identity_2 = MaxNode::find_identity_operation(in(1), in(2));
1738   if (identity_2 != nullptr) {
1739     return identity_2;
1740   }
1741 
1742   return AddNode::Identity(phase);
1743 }
1744 
1745 //------------------------------add_ring---------------------------------------
1746 const Type* MinHFNode::add_ring(const Type* t0, const Type* t1) const {
1747   const TypeH* r0 = t0->isa_half_float_constant();
1748   const TypeH* r1 = t1->isa_half_float_constant();
1749   if (r0 == nullptr || r1 == nullptr) {
1750     return bottom_type();
1751   }
1752 
1753   if (r0->is_nan()) {
1754     return r0;
1755   }
1756   if (r1->is_nan()) {
1757     return r1;
1758   }
1759 
1760   float f0 = r0->getf();
1761   float f1 = r1->getf();
1762   if (f0 != 0.0f || f1 != 0.0f) {
1763     return f0 < f1 ? r0 : r1;
1764   }
1765 
1766   // As per IEEE 754 specification, floating point comparison consider +ve and -ve
1767   // zeros as equals. Thus, performing signed integral comparison for min value
1768   // detection.
1769   return (jint_cast(f0) < jint_cast(f1)) ? r0 : r1;
1770 }
1771 
1772 //------------------------------add_ring---------------------------------------
1773 const Type* MinFNode::add_ring(const Type* t0, const Type* t1 ) const {
1774   const TypeF* r0 = t0->isa_float_constant();
1775   const TypeF* r1 = t1->isa_float_constant();
1776   if (r0 == nullptr || r1 == nullptr) {
1777     return bottom_type();
1778   }
1779 
1780   if (r0->is_nan()) {
1781     return r0;
1782   }
1783   if (r1->is_nan()) {
1784     return r1;
1785   }
1786 
1787   float f0 = r0->getf();
1788   float f1 = r1->getf();
1789   if (f0 != 0.0f || f1 != 0.0f) {
1790     return f0 < f1 ? r0 : r1;
1791   }
1792 
1793   // handle min of 0.0, -0.0 case.
1794   return (jint_cast(f0) < jint_cast(f1)) ? r0 : r1;
1795 }
1796 
1797 //------------------------------add_ring---------------------------------------
1798 const Type* MinDNode::add_ring(const Type* t0, const Type* t1) const {
1799   const TypeD* r0 = t0->isa_double_constant();
1800   const TypeD* r1 = t1->isa_double_constant();
1801   if (r0 == nullptr || r1 == nullptr) {
1802     return bottom_type();
1803   }
1804 
1805   if (r0->is_nan()) {
1806     return r0;
1807   }
1808   if (r1->is_nan()) {
1809     return r1;
1810   }
1811 
1812   double d0 = r0->getd();
1813   double d1 = r1->getd();
1814   if (d0 != 0.0 || d1 != 0.0) {
1815     return d0 < d1 ? r0 : r1;
1816   }
1817 
1818   // handle min of 0.0, -0.0 case.
1819   return (jlong_cast(d0) < jlong_cast(d1)) ? r0 : r1;
1820 }
1821 
1822 //------------------------------add_ring---------------------------------------
1823 const Type* MaxHFNode::add_ring(const Type* t0, const Type* t1) const {
1824   const TypeH* r0 = t0->isa_half_float_constant();
1825   const TypeH* r1 = t1->isa_half_float_constant();
1826   if (r0 == nullptr || r1 == nullptr) {
1827     return bottom_type();
1828   }
1829 
1830   if (r0->is_nan()) {
1831     return r0;
1832   }
1833   if (r1->is_nan()) {
1834     return r1;
1835   }
1836 
1837   float f0 = r0->getf();
1838   float f1 = r1->getf();
1839   if (f0 != 0.0f || f1 != 0.0f) {
1840     return f0 > f1 ? r0 : r1;
1841   }
1842 
1843   // As per IEEE 754 specification, floating point comparison consider +ve and -ve
1844   // zeros as equals. Thus, performing signed integral comparison for max value
1845   // detection.
1846   return (jint_cast(f0) > jint_cast(f1)) ? r0 : r1;
1847 }
1848 
1849 
1850 //------------------------------add_ring---------------------------------------
1851 const Type* MaxFNode::add_ring(const Type* t0, const Type* t1) const {
1852   const TypeF* r0 = t0->isa_float_constant();
1853   const TypeF* r1 = t1->isa_float_constant();
1854   if (r0 == nullptr || r1 == nullptr) {
1855     return bottom_type();
1856   }
1857 
1858   if (r0->is_nan()) {
1859     return r0;
1860   }
1861   if (r1->is_nan()) {
1862     return r1;
1863   }
1864 
1865   float f0 = r0->getf();
1866   float f1 = r1->getf();
1867   if (f0 != 0.0f || f1 != 0.0f) {
1868     return f0 > f1 ? r0 : r1;
1869   }
1870 
1871   // handle max of 0.0,-0.0 case.
1872   return (jint_cast(f0) > jint_cast(f1)) ? r0 : r1;
1873 }
1874 
1875 //------------------------------add_ring---------------------------------------
1876 const Type* MaxDNode::add_ring(const Type* t0, const Type* t1) const {
1877   const TypeD* r0 = t0->isa_double_constant();
1878   const TypeD* r1 = t1->isa_double_constant();
1879   if (r0 == nullptr || r1 == nullptr) {
1880     return bottom_type();
1881   }
1882 
1883   if (r0->is_nan()) {
1884     return r0;
1885   }
1886   if (r1->is_nan()) {
1887     return r1;
1888   }
1889 
1890   double d0 = r0->getd();
1891   double d1 = r1->getd();
1892   if (d0 != 0.0 || d1 != 0.0) {
1893     return d0 > d1 ? r0 : r1;
1894   }
1895 
1896   // handle max of 0.0, -0.0 case.
1897   return (jlong_cast(d0) > jlong_cast(d1)) ? r0 : r1;
1898 }