1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "memory/allocation.inline.hpp"
  27 #include "opto/addnode.hpp"
  28 #include "opto/castnode.hpp"
  29 #include "opto/cfgnode.hpp"
  30 #include "opto/connode.hpp"
  31 #include "opto/machnode.hpp"
  32 #include "opto/movenode.hpp"
  33 #include "opto/mulnode.hpp"
  34 #include "opto/phaseX.hpp"
  35 #include "opto/subnode.hpp"
  36 
  37 // Portions of code courtesy of Clifford Click
  38 
  39 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  40 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  41 // all inherited from this class.  The various identity values are supplied
  42 // by virtual functions.
  43 
  44 
  45 //=============================================================================
  46 //------------------------------hash-------------------------------------------
  47 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  48 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  49 // the same value in the presence of edge swapping.
  50 uint AddNode::hash() const {
  51   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  52 }
  53 
  54 //------------------------------Identity---------------------------------------
  55 // If either input is a constant 0, return the other input.
  56 Node* AddNode::Identity(PhaseGVN* phase) {
  57   const Type *zero = add_id();  // The additive identity
  58   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  59   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  60   return this;
  61 }
  62 
  63 //------------------------------commute----------------------------------------
  64 // Commute operands to move loads and constants to the right.
  65 static bool commute(PhaseGVN* phase, Node* add) {
  66   Node *in1 = add->in(1);
  67   Node *in2 = add->in(2);
  68 
  69   // convert "max(a,b) + min(a,b)" into "a+b".
  70   if ((in1->Opcode() == add->as_Add()->max_opcode() && in2->Opcode() == add->as_Add()->min_opcode())
  71       || (in1->Opcode() == add->as_Add()->min_opcode() && in2->Opcode() == add->as_Add()->max_opcode())) {
  72     Node *in11 = in1->in(1);
  73     Node *in12 = in1->in(2);
  74 
  75     Node *in21 = in2->in(1);
  76     Node *in22 = in2->in(2);
  77 
  78     if ((in11 == in21 && in12 == in22) ||
  79         (in11 == in22 && in12 == in21)) {
  80       add->set_req_X(1, in11, phase);
  81       add->set_req_X(2, in12, phase);
  82       return true;
  83     }
  84   }
  85 
  86   bool con_left = phase->type(in1)->singleton();
  87   bool con_right = phase->type(in2)->singleton();
  88 
  89   // Convert "1+x" into "x+1".
  90   // Right is a constant; leave it
  91   if( con_right ) return false;
  92   // Left is a constant; move it right.
  93   if( con_left ) {
  94     add->swap_edges(1, 2);
  95     return true;
  96   }
  97 
  98   // Convert "Load+x" into "x+Load".
  99   // Now check for loads
 100   if (in2->is_Load()) {
 101     if (!in1->is_Load()) {
 102       // already x+Load to return
 103       return false;
 104     }
 105     // both are loads, so fall through to sort inputs by idx
 106   } else if( in1->is_Load() ) {
 107     // Left is a Load and Right is not; move it right.
 108     add->swap_edges(1, 2);
 109     return true;
 110   }
 111 
 112   PhiNode *phi;
 113   // Check for tight loop increments: Loop-phi of Add of loop-phi
 114   if (in1->is_Phi() && (phi = in1->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add)
 115     return false;
 116   if (in2->is_Phi() && (phi = in2->as_Phi()) && phi->region()->is_Loop() && phi->in(2) == add) {
 117     add->swap_edges(1, 2);
 118     return true;
 119   }
 120 
 121   // Otherwise, sort inputs (commutativity) to help value numbering.
 122   if( in1->_idx > in2->_idx ) {
 123     add->swap_edges(1, 2);
 124     return true;
 125   }
 126   return false;
 127 }
 128 
 129 //------------------------------Idealize---------------------------------------
 130 // If we get here, we assume we are associative!
 131 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 132   const Type *t1 = phase->type(in(1));
 133   const Type *t2 = phase->type(in(2));
 134   bool con_left  = t1->singleton();
 135   bool con_right = t2->singleton();
 136 
 137   // Check for commutative operation desired
 138   if (commute(phase, this)) return this;
 139 
 140   AddNode *progress = NULL;             // Progress flag
 141 
 142   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 143   // constant, and the left input is an add of a constant, flatten the
 144   // expression tree.
 145   Node *add1 = in(1);
 146   Node *add2 = in(2);
 147   int add1_op = add1->Opcode();
 148   int this_op = Opcode();
 149   if (con_right && t2 != Type::TOP && // Right input is a constant?
 150       add1_op == this_op) { // Left input is an Add?
 151 
 152     // Type of left _in right input
 153     const Type *t12 = phase->type(add1->in(2));
 154     if (t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
 155       // Check for rare case of closed data cycle which can happen inside
 156       // unreachable loops. In these cases the computation is undefined.
 157 #ifdef ASSERT
 158       Node *add11    = add1->in(1);
 159       int   add11_op = add11->Opcode();
 160       if ((add1 == add1->in(1))
 161           || (add11_op == this_op && add11->in(1) == add1)) {
 162         assert(false, "dead loop in AddNode::Ideal");
 163       }
 164 #endif
 165       // The Add of the flattened expression
 166       Node *x1 = add1->in(1);
 167       Node *x2 = phase->makecon(add1->as_Add()->add_ring(t2, t12));
 168       set_req_X(2, x2, phase);
 169       set_req_X(1, x1, phase);
 170       progress = this;            // Made progress
 171       add1 = in(1);
 172       add1_op = add1->Opcode();
 173     }
 174   }
 175 
 176   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 177   if (add1_op == this_op && !con_right) {
 178     Node *a12 = add1->in(2);
 179     const Type *t12 = phase->type( a12 );
 180     if (t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 181         !(add1->in(1)->is_Phi() && (add1->in(1)->as_Phi()->is_tripcount(T_INT) || add1->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 182       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 183       add2 = add1->clone();
 184       add2->set_req(2, in(2));
 185       add2 = phase->transform(add2);
 186       set_req_X(1, add2, phase);
 187       set_req_X(2, a12, phase);
 188       progress = this;
 189       add2 = a12;
 190     }
 191   }
 192 
 193   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 194   int add2_op = add2->Opcode();
 195   if (add2_op == this_op && !con_left) {
 196     Node *a22 = add2->in(2);
 197     const Type *t22 = phase->type( a22 );
 198     if (t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 199         !(add2->in(1)->is_Phi() && (add2->in(1)->as_Phi()->is_tripcount(T_INT) || add2->in(1)->as_Phi()->is_tripcount(T_LONG)))) {
 200       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 201       Node *addx = add2->clone();
 202       addx->set_req(1, in(1));
 203       addx->set_req(2, add2->in(1));
 204       addx = phase->transform(addx);
 205       set_req_X(1, addx, phase);
 206       set_req_X(2, a22, phase);
 207       progress = this;
 208     }
 209   }
 210 
 211   return progress;
 212 }
 213 
 214 //------------------------------Value-----------------------------------------
 215 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 216 // the other input's symbols.
 217 const Type* AddNode::Value(PhaseGVN* phase) const {
 218   // Either input is TOP ==> the result is TOP
 219   const Type *t1 = phase->type( in(1) );
 220   const Type *t2 = phase->type( in(2) );
 221   if( t1 == Type::TOP ) return Type::TOP;
 222   if( t2 == Type::TOP ) return Type::TOP;
 223 
 224   // Either input is BOTTOM ==> the result is the local BOTTOM
 225   const Type *bot = bottom_type();
 226   if( (t1 == bot) || (t2 == bot) ||
 227       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 228     return bot;
 229 
 230   // Check for an addition involving the additive identity
 231   const Type *tadd = add_of_identity( t1, t2 );
 232   if( tadd ) return tadd;
 233 
 234   return add_ring(t1,t2);               // Local flavor of type addition
 235 }
 236 
 237 //------------------------------add_identity-----------------------------------
 238 // Check for addition of the identity
 239 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 240   const Type *zero = add_id();  // The additive identity
 241   if( t1->higher_equal( zero ) ) return t2;
 242   if( t2->higher_equal( zero ) ) return t1;
 243 
 244   return NULL;
 245 }
 246 
 247 AddNode* AddNode::make(Node* in1, Node* in2, BasicType bt) {
 248   switch (bt) {
 249     case T_INT:
 250       return new AddINode(in1, in2);
 251     case T_LONG:
 252       return new AddLNode(in1, in2);
 253     default:
 254       fatal("Not implemented for %s", type2name(bt));
 255   }
 256   return NULL;
 257 }
 258 
 259 //=============================================================================
 260 //------------------------------Idealize---------------------------------------
 261 Node* AddNode::IdealIL(PhaseGVN* phase, bool can_reshape, BasicType bt) {
 262   Node* in1 = in(1);
 263   Node* in2 = in(2);
 264   int op1 = in1->Opcode();
 265   int op2 = in2->Opcode();
 266   // Fold (con1-x)+con2 into (con1+con2)-x
 267   if (op1 == Op_Add(bt) && op2 == Op_Sub(bt)) {
 268     // Swap edges to try optimizations below
 269     in1 = in2;
 270     in2 = in(1);
 271     op1 = op2;
 272     op2 = in2->Opcode();
 273   }
 274   if (op1 == Op_Sub(bt)) {
 275     const Type* t_sub1 = phase->type(in1->in(1));
 276     const Type* t_2    = phase->type(in2       );
 277     if (t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP) {
 278       return SubNode::make(phase->makecon(add_ring(t_sub1, t_2)), in1->in(2), bt);
 279     }
 280     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 281     if (op2 == Op_Sub(bt)) {
 282       // Check for dead cycle: d = (a-b)+(c-d)
 283       assert( in1->in(2) != this && in2->in(2) != this,
 284               "dead loop in AddINode::Ideal" );
 285       Node* sub = SubNode::make(NULL, NULL, bt);
 286       sub->init_req(1, phase->transform(AddNode::make(in1->in(1), in2->in(1), bt)));
 287       sub->init_req(2, phase->transform(AddNode::make(in1->in(2), in2->in(2), bt)));
 288       return sub;
 289     }
 290     // Convert "(a-b)+(b+c)" into "(a+c)"
 291     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(1)) {
 292       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 293       return AddNode::make(in1->in(1), in2->in(2), bt);
 294     }
 295     // Convert "(a-b)+(c+b)" into "(a+c)"
 296     if (op2 == Op_Add(bt) && in1->in(2) == in2->in(2)) {
 297       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal/AddLNode::Ideal");
 298       return AddNode::make(in1->in(1), in2->in(1), bt);
 299     }
 300   }
 301 
 302   // Convert (con - y) + x into "(x - y) + con"
 303   if (op1 == Op_Sub(bt) && in1->in(1)->Opcode() == Op_ConIL(bt)
 304       && in1 != in1->in(2) && !(in1->in(2)->is_Phi() && in1->in(2)->as_Phi()->is_tripcount(bt))) {
 305     return AddNode::make(phase->transform(SubNode::make(in2, in1->in(2), bt)), in1->in(1), bt);
 306   }
 307 
 308   // Convert x + (con - y) into "(x - y) + con"
 309   if (op2 == Op_Sub(bt) && in2->in(1)->Opcode() == Op_ConIL(bt)
 310       && in2 != in2->in(2) && !(in2->in(2)->is_Phi() && in2->in(2)->as_Phi()->is_tripcount(bt))) {
 311     return AddNode::make(phase->transform(SubNode::make(in1, in2->in(2), bt)), in2->in(1), bt);
 312   }
 313 
 314   // Associative
 315   if (op1 == Op_Mul(bt) && op2 == Op_Mul(bt)) {
 316     Node* add_in1 = NULL;
 317     Node* add_in2 = NULL;
 318     Node* mul_in = NULL;
 319 
 320     if (in1->in(1) == in2->in(1)) {
 321       // Convert "a*b+a*c into a*(b+c)
 322       add_in1 = in1->in(2);
 323       add_in2 = in2->in(2);
 324       mul_in = in1->in(1);
 325     } else if (in1->in(2) == in2->in(1)) {
 326       // Convert a*b+b*c into b*(a+c)
 327       add_in1 = in1->in(1);
 328       add_in2 = in2->in(2);
 329       mul_in = in1->in(2);
 330     } else if (in1->in(2) == in2->in(2)) {
 331       // Convert a*c+b*c into (a+b)*c
 332       add_in1 = in1->in(1);
 333       add_in2 = in2->in(1);
 334       mul_in = in1->in(2);
 335     } else if (in1->in(1) == in2->in(2)) {
 336       // Convert a*b+c*a into a*(b+c)
 337       add_in1 = in1->in(2);
 338       add_in2 = in2->in(1);
 339       mul_in = in1->in(1);
 340     }
 341 
 342     if (mul_in != NULL) {
 343       Node* add = phase->transform(AddNode::make(add_in1, add_in2, bt));
 344       return MulNode::make(mul_in, add, bt);
 345     }
 346   }
 347 
 348   // Convert (x >>> rshift) + (x << lshift) into RotateRight(x, rshift)
 349   if (Matcher::match_rule_supported(Op_RotateRight) &&
 350       ((op1 == Op_URShift(bt) && op2 == Op_LShift(bt)) || (op1 == Op_LShift(bt) && op2 == Op_URShift(bt))) &&
 351       in1->in(1) != NULL && in1->in(1) == in2->in(1)) {
 352     Node* rshift = op1 == Op_URShift(bt) ? in1->in(2) : in2->in(2);
 353     Node* lshift = op1 == Op_URShift(bt) ? in2->in(2) : in1->in(2);
 354     if (rshift != NULL && lshift != NULL) {
 355       const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 356       const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 357       int bits = bt == T_INT ? 32 : 64;
 358       int mask = bt == T_INT ? 0x1F : 0x3F;
 359       if (lshift_t != NULL && lshift_t->is_con() &&
 360           rshift_t != NULL && rshift_t->is_con() &&
 361           ((lshift_t->get_con() & mask) == (bits - (rshift_t->get_con() & mask)))) {
 362         return new RotateRightNode(in1->in(1), phase->intcon(rshift_t->get_con() & mask), TypeInteger::bottom(bt));
 363       }
 364     }
 365   }
 366 
 367   return AddNode::Ideal(phase, can_reshape);
 368 }
 369 
 370 
 371 Node* AddINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 372   Node* in1 = in(1);
 373   Node* in2 = in(2);
 374   int op1 = in1->Opcode();
 375   int op2 = in2->Opcode();
 376 
 377   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 378   // Helps with array allocation math constant folding
 379   // See 4790063:
 380   // Unrestricted transformation is unsafe for some runtime values of 'x'
 381   // ( x ==  0, z == 1, y == -1 ) fails
 382   // ( x == -5, z == 1, y ==  1 ) fails
 383   // Transform works for small z and small negative y when the addition
 384   // (x + (y << z)) does not cross zero.
 385   // Implement support for negative y and (x >= -(y << z))
 386   // Have not observed cases where type information exists to support
 387   // positive y and (x <= -(y << z))
 388   if (op1 == Op_URShiftI && op2 == Op_ConI &&
 389       in1->in(2)->Opcode() == Op_ConI) {
 390     jint z = phase->type(in1->in(2))->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 391     jint y = phase->type(in2)->is_int()->get_con();
 392 
 393     if (z < 5 && -5 < y && y < 0) {
 394       const Type* t_in11 = phase->type(in1->in(1));
 395       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z))) {
 396         Node* a = phase->transform(new AddINode( in1->in(1), phase->intcon(y<<z)));
 397         return new URShiftINode(a, in1->in(2));
 398       }
 399     }
 400   }
 401 
 402   return AddNode::IdealIL(phase, can_reshape, T_INT);
 403 }
 404 
 405 
 406 //------------------------------Identity---------------------------------------
 407 // Fold (x-y)+y  OR  y+(x-y)  into  x
 408 Node* AddINode::Identity(PhaseGVN* phase) {
 409   if (in(1)->Opcode() == Op_SubI && in(1)->in(2) == in(2)) {
 410     return in(1)->in(1);
 411   } else if (in(2)->Opcode() == Op_SubI && in(2)->in(2) == in(1)) {
 412     return in(2)->in(1);
 413   }
 414   return AddNode::Identity(phase);
 415 }
 416 
 417 
 418 //------------------------------add_ring---------------------------------------
 419 // Supplied function returns the sum of the inputs.  Guaranteed never
 420 // to be passed a TOP or BOTTOM type, these are filtered out by
 421 // pre-check.
 422 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 423   const TypeInt *r0 = t0->is_int(); // Handy access
 424   const TypeInt *r1 = t1->is_int();
 425   int lo = java_add(r0->_lo, r1->_lo);
 426   int hi = java_add(r0->_hi, r1->_hi);
 427   if( !(r0->is_con() && r1->is_con()) ) {
 428     // Not both constants, compute approximate result
 429     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 430       lo = min_jint; hi = max_jint; // Underflow on the low side
 431     }
 432     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 433       lo = min_jint; hi = max_jint; // Overflow on the high side
 434     }
 435     if( lo > hi ) {               // Handle overflow
 436       lo = min_jint; hi = max_jint;
 437     }
 438   } else {
 439     // both constants, compute precise result using 'lo' and 'hi'
 440     // Semantics define overflow and underflow for integer addition
 441     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 442   }
 443   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 444 }
 445 
 446 
 447 //=============================================================================
 448 //------------------------------Idealize---------------------------------------
 449 Node* AddLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 450   return AddNode::IdealIL(phase, can_reshape, T_LONG);
 451 }
 452 
 453 
 454 //------------------------------Identity---------------------------------------
 455 // Fold (x-y)+y  OR  y+(x-y)  into  x
 456 Node* AddLNode::Identity(PhaseGVN* phase) {
 457   if (in(1)->Opcode() == Op_SubL && in(1)->in(2) == in(2)) {
 458     return in(1)->in(1);
 459   } else if (in(2)->Opcode() == Op_SubL && in(2)->in(2) == in(1)) {
 460     return in(2)->in(1);
 461   }
 462   return AddNode::Identity(phase);
 463 }
 464 
 465 
 466 //------------------------------add_ring---------------------------------------
 467 // Supplied function returns the sum of the inputs.  Guaranteed never
 468 // to be passed a TOP or BOTTOM type, these are filtered out by
 469 // pre-check.
 470 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 471   const TypeLong *r0 = t0->is_long(); // Handy access
 472   const TypeLong *r1 = t1->is_long();
 473   jlong lo = java_add(r0->_lo, r1->_lo);
 474   jlong hi = java_add(r0->_hi, r1->_hi);
 475   if( !(r0->is_con() && r1->is_con()) ) {
 476     // Not both constants, compute approximate result
 477     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 478       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 479     }
 480     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 481       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 482     }
 483     if( lo > hi ) {               // Handle overflow
 484       lo = min_jlong; hi = max_jlong;
 485     }
 486   } else {
 487     // both constants, compute precise result using 'lo' and 'hi'
 488     // Semantics define overflow and underflow for integer addition
 489     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 490   }
 491   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 492 }
 493 
 494 
 495 //=============================================================================
 496 //------------------------------add_of_identity--------------------------------
 497 // Check for addition of the identity
 498 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 499   // x ADD 0  should return x unless 'x' is a -zero
 500   //
 501   // const Type *zero = add_id();     // The additive identity
 502   // jfloat f1 = t1->getf();
 503   // jfloat f2 = t2->getf();
 504   //
 505   // if( t1->higher_equal( zero ) ) return t2;
 506   // if( t2->higher_equal( zero ) ) return t1;
 507 
 508   return NULL;
 509 }
 510 
 511 //------------------------------add_ring---------------------------------------
 512 // Supplied function returns the sum of the inputs.
 513 // This also type-checks the inputs for sanity.  Guaranteed never to
 514 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 515 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 516   // We must be adding 2 float constants.
 517   return TypeF::make( t0->getf() + t1->getf() );
 518 }
 519 
 520 //------------------------------Ideal------------------------------------------
 521 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 522   // Floating point additions are not associative because of boundary conditions (infinity)
 523   return commute(phase, this) ? this : NULL;
 524 }
 525 
 526 
 527 //=============================================================================
 528 //------------------------------add_of_identity--------------------------------
 529 // Check for addition of the identity
 530 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 531   // x ADD 0  should return x unless 'x' is a -zero
 532   //
 533   // const Type *zero = add_id();     // The additive identity
 534   // jfloat f1 = t1->getf();
 535   // jfloat f2 = t2->getf();
 536   //
 537   // if( t1->higher_equal( zero ) ) return t2;
 538   // if( t2->higher_equal( zero ) ) return t1;
 539 
 540   return NULL;
 541 }
 542 //------------------------------add_ring---------------------------------------
 543 // Supplied function returns the sum of the inputs.
 544 // This also type-checks the inputs for sanity.  Guaranteed never to
 545 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 546 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 547   // We must be adding 2 double constants.
 548   return TypeD::make( t0->getd() + t1->getd() );
 549 }
 550 
 551 //------------------------------Ideal------------------------------------------
 552 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 553   // Floating point additions are not associative because of boundary conditions (infinity)
 554   return commute(phase, this) ? this : NULL;
 555 }
 556 
 557 
 558 //=============================================================================
 559 //------------------------------Identity---------------------------------------
 560 // If one input is a constant 0, return the other input.
 561 Node* AddPNode::Identity(PhaseGVN* phase) {
 562   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 563 }
 564 
 565 //------------------------------Idealize---------------------------------------
 566 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 567   // Bail out if dead inputs
 568   if( phase->type( in(Address) ) == Type::TOP ) return NULL;
 569 
 570   // If the left input is an add of a constant, flatten the expression tree.
 571   const Node *n = in(Address);
 572   if (n->is_AddP() && n->in(Base) == in(Base)) {
 573     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 574     assert( !addp->in(Address)->is_AddP() ||
 575              addp->in(Address)->as_AddP() != addp,
 576             "dead loop in AddPNode::Ideal" );
 577     // Type of left input's right input
 578     const Type *t = phase->type( addp->in(Offset) );
 579     if( t == Type::TOP ) return NULL;
 580     const TypeX *t12 = t->is_intptr_t();
 581     if( t12->is_con() ) {       // Left input is an add of a constant?
 582       // If the right input is a constant, combine constants
 583       const Type *temp_t2 = phase->type( in(Offset) );
 584       if( temp_t2 == Type::TOP ) return NULL;
 585       const TypeX *t2 = temp_t2->is_intptr_t();
 586       Node* address;
 587       Node* offset;
 588       if( t2->is_con() ) {
 589         // The Add of the flattened expression
 590         address = addp->in(Address);
 591         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 592       } else {
 593         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 594         address = phase->transform(new AddPNode(in(Base),addp->in(Address),in(Offset)));
 595         offset  = addp->in(Offset);
 596       }
 597       set_req_X(Address, address, phase);
 598       set_req_X(Offset, offset, phase);
 599       return this;
 600     }
 601   }
 602 
 603   // Raw pointers?
 604   if( in(Base)->bottom_type() == Type::TOP ) {
 605     // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.
 606     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
 607       Node* offset = in(Offset);
 608       return new CastX2PNode(offset);
 609     }
 610   }
 611 
 612   // If the right is an add of a constant, push the offset down.
 613   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
 614   // The idea is to merge array_base+scaled_index groups together,
 615   // and only have different constant offsets from the same base.
 616   const Node *add = in(Offset);
 617   if( add->Opcode() == Op_AddX && add->in(1) != add ) {
 618     const Type *t22 = phase->type( add->in(2) );
 619     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?
 620       set_req(Address, phase->transform(new AddPNode(in(Base),in(Address),add->in(1))));
 621       set_req_X(Offset, add->in(2), phase); // puts add on igvn worklist if needed
 622       return this;              // Made progress
 623     }
 624   }
 625 
 626   return NULL;                  // No progress
 627 }
 628 
 629 //------------------------------bottom_type------------------------------------
 630 // Bottom-type is the pointer-type with unknown offset.
 631 const Type *AddPNode::bottom_type() const {
 632   if (in(Address) == NULL)  return TypePtr::BOTTOM;
 633   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
 634   if( !tp ) return Type::TOP;   // TOP input means TOP output
 635   assert( in(Offset)->Opcode() != Op_ConP, "" );
 636   const Type *t = in(Offset)->bottom_type();
 637   if( t == Type::TOP )
 638     return tp->add_offset(Type::OffsetTop);
 639   const TypeX *tx = t->is_intptr_t();
 640   intptr_t txoffset = Type::OffsetBot;
 641   if (tx->is_con()) {   // Left input is an add of a constant?
 642     txoffset = tx->get_con();
 643   }
 644   if (tp->isa_aryptr()) {
 645     // In the case of a flattened inline type array, each field has its
 646     // own slice so we need to extract the field being accessed from
 647     // the address computation
 648     return tp->is_aryptr()->add_field_offset_and_offset(txoffset);
 649   }
 650   return tp->add_offset(txoffset);
 651 }
 652 
 653 //------------------------------Value------------------------------------------
 654 const Type* AddPNode::Value(PhaseGVN* phase) const {
 655   // Either input is TOP ==> the result is TOP
 656   const Type *t1 = phase->type( in(Address) );
 657   const Type *t2 = phase->type( in(Offset) );
 658   if( t1 == Type::TOP ) return Type::TOP;
 659   if( t2 == Type::TOP ) return Type::TOP;
 660 
 661   // Left input is a pointer
 662   const TypePtr *p1 = t1->isa_ptr();
 663   // Right input is an int
 664   const TypeX *p2 = t2->is_intptr_t();
 665   // Add 'em
 666   intptr_t p2offset = Type::OffsetBot;
 667   if (p2->is_con()) {   // Left input is an add of a constant?
 668     p2offset = p2->get_con();
 669   }
 670   if (p1->isa_aryptr()) {
 671     // In the case of a flattened inline type array, each field has its
 672     // own slice so we need to extract the field being accessed from
 673     // the address computation
 674     return p1->is_aryptr()->add_field_offset_and_offset(p2offset);
 675   }
 676   return p1->add_offset(p2offset);
 677 }
 678 
 679 //------------------------Ideal_base_and_offset--------------------------------
 680 // Split an oop pointer into a base and offset.
 681 // (The offset might be Type::OffsetBot in the case of an array.)
 682 // Return the base, or NULL if failure.
 683 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseTransform* phase,
 684                                       // second return value:
 685                                       intptr_t& offset) {
 686   if (ptr->is_AddP()) {
 687     Node* base = ptr->in(AddPNode::Base);
 688     Node* addr = ptr->in(AddPNode::Address);
 689     Node* offs = ptr->in(AddPNode::Offset);
 690     if (base == addr || base->is_top()) {
 691       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 692       if (offset != Type::OffsetBot) {
 693         return addr;
 694       }
 695     }
 696   }
 697   offset = Type::OffsetBot;
 698   return NULL;
 699 }
 700 
 701 //------------------------------unpack_offsets----------------------------------
 702 // Collect the AddP offset values into the elements array, giving up
 703 // if there are more than length.
 704 int AddPNode::unpack_offsets(Node* elements[], int length) {
 705   int count = 0;
 706   Node* addr = this;
 707   Node* base = addr->in(AddPNode::Base);
 708   while (addr->is_AddP()) {
 709     if (addr->in(AddPNode::Base) != base) {
 710       // give up
 711       return -1;
 712     }
 713     elements[count++] = addr->in(AddPNode::Offset);
 714     if (count == length) {
 715       // give up
 716       return -1;
 717     }
 718     addr = addr->in(AddPNode::Address);
 719   }
 720   if (addr != base) {
 721     return -1;
 722   }
 723   return count;
 724 }
 725 
 726 //------------------------------match_edge-------------------------------------
 727 // Do we Match on this edge index or not?  Do not match base pointer edge
 728 uint AddPNode::match_edge(uint idx) const {
 729   return idx > Base;
 730 }
 731 
 732 //=============================================================================
 733 //------------------------------Identity---------------------------------------
 734 Node* OrINode::Identity(PhaseGVN* phase) {
 735   // x | x => x
 736   if (in(1) == in(2)) {
 737     return in(1);
 738   }
 739 
 740   return AddNode::Identity(phase);
 741 }
 742 
 743 // Find shift value for Integer or Long OR.
 744 Node* rotate_shift(PhaseGVN* phase, Node* lshift, Node* rshift, int mask) {
 745   // val << norm_con_shift | val >> ({32|64} - norm_con_shift) => rotate_left val, norm_con_shift
 746   const TypeInt* lshift_t = phase->type(lshift)->isa_int();
 747   const TypeInt* rshift_t = phase->type(rshift)->isa_int();
 748   if (lshift_t != NULL && lshift_t->is_con() &&
 749       rshift_t != NULL && rshift_t->is_con() &&
 750       ((lshift_t->get_con() & mask) == ((mask + 1) - (rshift_t->get_con() & mask)))) {
 751     return phase->intcon(lshift_t->get_con() & mask);
 752   }
 753   // val << var_shift | val >> ({0|32|64} - var_shift) => rotate_left val, var_shift
 754   if (rshift->Opcode() == Op_SubI && rshift->in(2) == lshift && rshift->in(1)->is_Con()){
 755     const TypeInt* shift_t = phase->type(rshift->in(1))->isa_int();
 756     if (shift_t != NULL && shift_t->is_con() &&
 757         (shift_t->get_con() == 0 || shift_t->get_con() == (mask + 1))) {
 758       return lshift;
 759     }
 760   }
 761   return NULL;
 762 }
 763 
 764 Node* OrINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 765   int lopcode = in(1)->Opcode();
 766   int ropcode = in(2)->Opcode();
 767   if (Matcher::match_rule_supported(Op_RotateLeft) &&
 768       lopcode == Op_LShiftI && ropcode == Op_URShiftI && in(1)->in(1) == in(2)->in(1)) {
 769     Node* lshift = in(1)->in(2);
 770     Node* rshift = in(2)->in(2);
 771     Node* shift = rotate_shift(phase, lshift, rshift, 0x1F);
 772     if (shift != NULL) {
 773       return new RotateLeftNode(in(1)->in(1), shift, TypeInt::INT);
 774     }
 775     return NULL;
 776   }
 777   if (Matcher::match_rule_supported(Op_RotateRight) &&
 778       lopcode == Op_URShiftI && ropcode == Op_LShiftI && in(1)->in(1) == in(2)->in(1)) {
 779     Node* rshift = in(1)->in(2);
 780     Node* lshift = in(2)->in(2);
 781     Node* shift = rotate_shift(phase, rshift, lshift, 0x1F);
 782     if (shift != NULL) {
 783       return new RotateRightNode(in(1)->in(1), shift, TypeInt::INT);
 784     }
 785   }
 786   return NULL;
 787 }
 788 
 789 //------------------------------add_ring---------------------------------------
 790 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 791 // the logical operations the ring's ADD is really a logical OR function.
 792 // This also type-checks the inputs for sanity.  Guaranteed never to
 793 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 794 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
 795   const TypeInt *r0 = t0->is_int(); // Handy access
 796   const TypeInt *r1 = t1->is_int();
 797 
 798   // If both args are bool, can figure out better types
 799   if ( r0 == TypeInt::BOOL ) {
 800     if ( r1 == TypeInt::ONE) {
 801       return TypeInt::ONE;
 802     } else if ( r1 == TypeInt::BOOL ) {
 803       return TypeInt::BOOL;
 804     }
 805   } else if ( r0 == TypeInt::ONE ) {
 806     if ( r1 == TypeInt::BOOL ) {
 807       return TypeInt::ONE;
 808     }
 809   }
 810 
 811   // If either input is not a constant, just return all integers.
 812   if( !r0->is_con() || !r1->is_con() )
 813     return TypeInt::INT;        // Any integer, but still no symbols.
 814 
 815   // Otherwise just OR them bits.
 816   return TypeInt::make( r0->get_con() | r1->get_con() );
 817 }
 818 
 819 //=============================================================================
 820 //------------------------------Identity---------------------------------------
 821 Node* OrLNode::Identity(PhaseGVN* phase) {
 822   // x | x => x
 823   if (in(1) == in(2)) {
 824     return in(1);
 825   }
 826 
 827   return AddNode::Identity(phase);
 828 }
 829 
 830 Node* OrLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 831   int lopcode = in(1)->Opcode();
 832   int ropcode = in(2)->Opcode();
 833   if (Matcher::match_rule_supported(Op_RotateLeft) &&
 834       lopcode == Op_LShiftL && ropcode == Op_URShiftL && in(1)->in(1) == in(2)->in(1)) {
 835     Node* lshift = in(1)->in(2);
 836     Node* rshift = in(2)->in(2);
 837     Node* shift = rotate_shift(phase, lshift, rshift, 0x3F);
 838     if (shift != NULL) {
 839       return new RotateLeftNode(in(1)->in(1), shift, TypeLong::LONG);
 840     }
 841     return NULL;
 842   }
 843   if (Matcher::match_rule_supported(Op_RotateRight) &&
 844       lopcode == Op_URShiftL && ropcode == Op_LShiftL && in(1)->in(1) == in(2)->in(1)) {
 845     Node* rshift = in(1)->in(2);
 846     Node* lshift = in(2)->in(2);
 847     Node* shift = rotate_shift(phase, rshift, lshift, 0x3F);
 848     if (shift != NULL) {
 849       return new RotateRightNode(in(1)->in(1), shift, TypeLong::LONG);
 850     }
 851   }
 852   return NULL;
 853 }
 854 
 855 //------------------------------add_ring---------------------------------------
 856 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
 857   const TypeLong *r0 = t0->is_long(); // Handy access
 858   const TypeLong *r1 = t1->is_long();
 859 
 860   // If either input is not a constant, just return all integers.
 861   if( !r0->is_con() || !r1->is_con() )
 862     return TypeLong::LONG;      // Any integer, but still no symbols.
 863 
 864   // Otherwise just OR them bits.
 865   return TypeLong::make( r0->get_con() | r1->get_con() );
 866 }
 867 
 868 //---------------------------Helper -------------------------------------------
 869 /* Decide if the given node is used only in arithmetic expressions(add or sub).
 870  */
 871 static bool is_used_in_only_arithmetic(Node* n, BasicType bt) {
 872   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 873     Node* u = n->fast_out(i);
 874     if (u->Opcode() != Op_Add(bt) && u->Opcode() != Op_Sub(bt)) {
 875       return false;
 876     }
 877   }
 878   return true;
 879 }
 880 
 881 //=============================================================================
 882 //------------------------------Idealize---------------------------------------
 883 Node* XorINode::Ideal(PhaseGVN* phase, bool can_reshape) {
 884   Node* in1 = in(1);
 885   Node* in2 = in(2);
 886 
 887   // Convert ~x into -1-x when ~x is used in an arithmetic expression
 888   // or x itself is an expression.
 889   if (phase->type(in2) == TypeInt::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
 890     if (phase->is_IterGVN()) {
 891       if (is_used_in_only_arithmetic(this, T_INT)
 892           // LHS is arithmetic
 893           || (in1->Opcode() == Op_AddI || in1->Opcode() == Op_SubI)) {
 894         return new SubINode(in2, in1);
 895       }
 896     } else {
 897       // graph could be incomplete in GVN so we postpone to IGVN
 898       phase->record_for_igvn(this);
 899     }
 900   }
 901   return AddNode::Ideal(phase, can_reshape);
 902 }
 903 
 904 const Type* XorINode::Value(PhaseGVN* phase) const {
 905   Node* in1 = in(1);
 906   Node* in2 = in(2);
 907   const Type* t1 = phase->type(in1);
 908   const Type* t2 = phase->type(in2);
 909   if (t1 == Type::TOP || t2 == Type::TOP) {
 910     return Type::TOP;
 911   }
 912   // x ^ x ==> 0
 913   if (in1->eqv_uncast(in2)) {
 914     return add_id();
 915   }
 916   // result of xor can only have bits sets where any of the
 917   // inputs have bits set. lo can always become 0.
 918   const TypeInt* t1i = t1->is_int();
 919   const TypeInt* t2i = t2->is_int();
 920   if ((t1i->_lo >= 0) &&
 921       (t1i->_hi > 0)  &&
 922       (t2i->_lo >= 0) &&
 923       (t2i->_hi > 0)) {
 924     // hi - set all bits below the highest bit. Using round_down to avoid overflow.
 925     const TypeInt* t1x = TypeInt::make(0, round_down_power_of_2(t1i->_hi) + (round_down_power_of_2(t1i->_hi) - 1), t1i->_widen);
 926     const TypeInt* t2x = TypeInt::make(0, round_down_power_of_2(t2i->_hi) + (round_down_power_of_2(t2i->_hi) - 1), t2i->_widen);
 927     return t1x->meet(t2x);
 928   }
 929   return AddNode::Value(phase);
 930 }
 931 
 932 
 933 //------------------------------add_ring---------------------------------------
 934 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 935 // the logical operations the ring's ADD is really a logical OR function.
 936 // This also type-checks the inputs for sanity.  Guaranteed never to
 937 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 938 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
 939   const TypeInt *r0 = t0->is_int(); // Handy access
 940   const TypeInt *r1 = t1->is_int();
 941 
 942   // Complementing a boolean?
 943   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE
 944                                || r1 == TypeInt::BOOL))
 945     return TypeInt::BOOL;
 946 
 947   if( !r0->is_con() || !r1->is_con() ) // Not constants
 948     return TypeInt::INT;        // Any integer, but still no symbols.
 949 
 950   // Otherwise just XOR them bits.
 951   return TypeInt::make( r0->get_con() ^ r1->get_con() );
 952 }
 953 
 954 //=============================================================================
 955 //------------------------------add_ring---------------------------------------
 956 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
 957   const TypeLong *r0 = t0->is_long(); // Handy access
 958   const TypeLong *r1 = t1->is_long();
 959 
 960   // If either input is not a constant, just return all integers.
 961   if( !r0->is_con() || !r1->is_con() )
 962     return TypeLong::LONG;      // Any integer, but still no symbols.
 963 
 964   // Otherwise just OR them bits.
 965   return TypeLong::make( r0->get_con() ^ r1->get_con() );
 966 }
 967 
 968 Node* XorLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 969   Node* in1 = in(1);
 970   Node* in2 = in(2);
 971 
 972   // Convert ~x into -1-x when ~x is used in an arithmetic expression
 973   // or x itself is an arithmetic expression.
 974   if (phase->type(in2) == TypeLong::MINUS_1) { // follows LHS^(-1), i.e., ~LHS
 975     if (phase->is_IterGVN()) {
 976       if (is_used_in_only_arithmetic(this, T_LONG)
 977           // LHS is arithmetic
 978           || (in1->Opcode() == Op_AddL || in1->Opcode() == Op_SubL)) {
 979         return new SubLNode(in2, in1);
 980       }
 981     } else {
 982       // graph could be incomplete in GVN so we postpone to IGVN
 983       phase->record_for_igvn(this);
 984     }
 985   }
 986   return AddNode::Ideal(phase, can_reshape);
 987 }
 988 
 989 const Type* XorLNode::Value(PhaseGVN* phase) const {
 990   Node* in1 = in(1);
 991   Node* in2 = in(2);
 992   const Type* t1 = phase->type(in1);
 993   const Type* t2 = phase->type(in2);
 994   if (t1 == Type::TOP || t2 == Type::TOP) {
 995     return Type::TOP;
 996   }
 997   // x ^ x ==> 0
 998   if (in1->eqv_uncast(in2)) {
 999     return add_id();
1000   }
1001   // result of xor can only have bits sets where any of the
1002   // inputs have bits set. lo can always become 0.
1003   const TypeLong* t1l = t1->is_long();
1004   const TypeLong* t2l = t2->is_long();
1005   if ((t1l->_lo >= 0) &&
1006       (t1l->_hi > 0)  &&
1007       (t2l->_lo >= 0) &&
1008       (t2l->_hi > 0)) {
1009     // hi - set all bits below the highest bit. Using round_down to avoid overflow.
1010     const TypeLong* t1x = TypeLong::make(0, round_down_power_of_2(t1l->_hi) + (round_down_power_of_2(t1l->_hi) - 1), t1l->_widen);
1011     const TypeLong* t2x = TypeLong::make(0, round_down_power_of_2(t2l->_hi) + (round_down_power_of_2(t2l->_hi) - 1), t2l->_widen);
1012     return t1x->meet(t2x);
1013   }
1014   return AddNode::Value(phase);
1015 }
1016 
1017 Node* MaxNode::build_min_max(Node* a, Node* b, bool is_max, bool is_unsigned, const Type* t, PhaseGVN& gvn) {
1018   bool is_int = gvn.type(a)->isa_int();
1019   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1020   assert(is_int == (gvn.type(b)->isa_int() != NULL), "inconsistent inputs");
1021   BasicType bt = is_int ? T_INT: T_LONG;
1022   Node* hook = NULL;
1023   if (gvn.is_IterGVN()) {
1024     // Make sure a and b are not destroyed
1025     hook = new Node(2);
1026     hook->init_req(0, a);
1027     hook->init_req(1, b);
1028   }
1029   Node* res = NULL;
1030   if (is_int && !is_unsigned) {
1031     if (is_max) {
1032       res =  gvn.transform(new MaxINode(a, b));
1033       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");
1034     } else {
1035       Node* res =  gvn.transform(new MinINode(a, b));
1036       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");
1037     }
1038   } else {
1039     Node* cmp = NULL;
1040     if (is_max) {
1041       cmp = gvn.transform(CmpNode::make(a, b, bt, is_unsigned));
1042     } else {
1043       cmp = gvn.transform(CmpNode::make(b, a, bt, is_unsigned));
1044     }
1045     Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1046     res = gvn.transform(CMoveNode::make(NULL, bol, a, b, t));
1047   }
1048   if (hook != NULL) {
1049     hook->destruct(&gvn);
1050   }
1051   return res;
1052 }
1053 
1054 Node* MaxNode::build_min_max_diff_with_zero(Node* a, Node* b, bool is_max, const Type* t, PhaseGVN& gvn) {
1055   bool is_int = gvn.type(a)->isa_int();
1056   assert(is_int || gvn.type(a)->isa_long(), "int or long inputs");
1057   assert(is_int == (gvn.type(b)->isa_int() != NULL), "inconsistent inputs");
1058   BasicType bt = is_int ? T_INT: T_LONG;
1059   Node* zero = gvn.integercon(0, bt);
1060   Node* hook = NULL;
1061   if (gvn.is_IterGVN()) {
1062     // Make sure a and b are not destroyed
1063     hook = new Node(2);
1064     hook->init_req(0, a);
1065     hook->init_req(1, b);
1066   }
1067   Node* cmp = NULL;
1068   if (is_max) {
1069     cmp = gvn.transform(CmpNode::make(a, b, bt, false));
1070   } else {
1071     cmp = gvn.transform(CmpNode::make(b, a, bt, false));
1072   }
1073   Node* sub = gvn.transform(SubNode::make(a, b, bt));
1074   Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::lt));
1075   Node* res = gvn.transform(CMoveNode::make(NULL, bol, sub, zero, t));
1076   if (hook != NULL) {
1077     hook->destruct(&gvn);
1078   }
1079   return res;
1080 }
1081 
1082 //=============================================================================
1083 //------------------------------add_ring---------------------------------------
1084 // Supplied function returns the sum of the inputs.
1085 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
1086   const TypeInt *r0 = t0->is_int(); // Handy access
1087   const TypeInt *r1 = t1->is_int();
1088 
1089   // Otherwise just MAX them bits.
1090   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1091 }
1092 
1093 // Check if addition of an integer with type 't' and a constant 'c' can overflow
1094 static bool can_overflow(const TypeInt* t, jint c) {
1095   jint t_lo = t->_lo;
1096   jint t_hi = t->_hi;
1097   return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
1098           (c > 0 && (java_add(t_hi, c) < t_hi)));
1099 }
1100 
1101 // Ideal transformations for MaxINode
1102 Node* MaxINode::Ideal(PhaseGVN* phase, bool can_reshape) {
1103   // Force a right-spline graph
1104   Node* l = in(1);
1105   Node* r = in(2);
1106   // Transform  MaxI1(MaxI2(a, b), c)  into  MaxI1(a, MaxI2(b, c))
1107   // to force a right-spline graph for the rest of MaxINode::Ideal().
1108   if (l->Opcode() == Op_MaxI) {
1109     assert(l != l->in(1), "dead loop in MaxINode::Ideal");
1110     r = phase->transform(new MaxINode(l->in(2), r));
1111     l = l->in(1);
1112     set_req_X(1, l, phase);
1113     set_req_X(2, r, phase);
1114     return this;
1115   }
1116 
1117   // Get left input & constant
1118   Node* x = l;
1119   jint x_off = 0;
1120   if (x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
1121       x->in(2)->is_Con()) {
1122     const Type* t = x->in(2)->bottom_type();
1123     if (t == Type::TOP) return NULL;  // No progress
1124     x_off = t->is_int()->get_con();
1125     x = x->in(1);
1126   }
1127 
1128   // Scan a right-spline-tree for MAXs
1129   Node* y = r;
1130   jint y_off = 0;
1131   // Check final part of MAX tree
1132   if (y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
1133       y->in(2)->is_Con()) {
1134     const Type* t = y->in(2)->bottom_type();
1135     if (t == Type::TOP) return NULL;  // No progress
1136     y_off = t->is_int()->get_con();
1137     y = y->in(1);
1138   }
1139   if (x->_idx > y->_idx && r->Opcode() != Op_MaxI) {
1140     swap_edges(1, 2);
1141     return this;
1142   }
1143 
1144   const TypeInt* tx = phase->type(x)->isa_int();
1145 
1146   if (r->Opcode() == Op_MaxI) {
1147     assert(r != r->in(2), "dead loop in MaxINode::Ideal");
1148     y = r->in(1);
1149     // Check final part of MAX tree
1150     if (y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
1151         y->in(2)->is_Con()) {
1152       const Type* t = y->in(2)->bottom_type();
1153       if (t == Type::TOP) return NULL;  // No progress
1154       y_off = t->is_int()->get_con();
1155       y = y->in(1);
1156     }
1157 
1158     if (x->_idx > y->_idx)
1159       return new MaxINode(r->in(1), phase->transform(new MaxINode(l, r->in(2))));
1160 
1161     // Transform MAX2(x + c0, MAX2(x + c1, z)) into MAX2(x + MAX2(c0, c1), z)
1162     // if x == y and the additions can't overflow.
1163     if (x == y && tx != NULL &&
1164         !can_overflow(tx, x_off) &&
1165         !can_overflow(tx, y_off)) {
1166       return new MaxINode(phase->transform(new AddINode(x, phase->intcon(MAX2(x_off, y_off)))), r->in(2));
1167     }
1168   } else {
1169     // Transform MAX2(x + c0, y + c1) into x + MAX2(c0, c1)
1170     // if x == y and the additions can't overflow.
1171     if (x == y && tx != NULL &&
1172         !can_overflow(tx, x_off) &&
1173         !can_overflow(tx, y_off)) {
1174       return new AddINode(x, phase->intcon(MAX2(x_off, y_off)));
1175     }
1176   }
1177  return NULL;
1178 }
1179 
1180 //=============================================================================
1181 //------------------------------Idealize---------------------------------------
1182 // MINs show up in range-check loop limit calculations.  Look for
1183 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
1184 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
1185   Node *progress = NULL;
1186   // Force a right-spline graph
1187   Node *l = in(1);
1188   Node *r = in(2);
1189   // Transform  MinI1( MinI2(a,b), c)  into  MinI1( a, MinI2(b,c) )
1190   // to force a right-spline graph for the rest of MinINode::Ideal().
1191   if( l->Opcode() == Op_MinI ) {
1192     assert( l != l->in(1), "dead loop in MinINode::Ideal" );
1193     r = phase->transform(new MinINode(l->in(2),r));
1194     l = l->in(1);
1195     set_req_X(1, l, phase);
1196     set_req_X(2, r, phase);
1197     return this;
1198   }
1199 
1200   // Get left input & constant
1201   Node *x = l;
1202   jint x_off = 0;
1203   if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
1204       x->in(2)->is_Con() ) {
1205     const Type *t = x->in(2)->bottom_type();
1206     if( t == Type::TOP ) return NULL;  // No progress
1207     x_off = t->is_int()->get_con();
1208     x = x->in(1);
1209   }
1210 
1211   // Scan a right-spline-tree for MINs
1212   Node *y = r;
1213   jint y_off = 0;
1214   // Check final part of MIN tree
1215   if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
1216       y->in(2)->is_Con() ) {
1217     const Type *t = y->in(2)->bottom_type();
1218     if( t == Type::TOP ) return NULL;  // No progress
1219     y_off = t->is_int()->get_con();
1220     y = y->in(1);
1221   }
1222   if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {
1223     swap_edges(1, 2);
1224     return this;
1225   }
1226 
1227   const TypeInt* tx = phase->type(x)->isa_int();
1228 
1229   if( r->Opcode() == Op_MinI ) {
1230     assert( r != r->in(2), "dead loop in MinINode::Ideal" );
1231     y = r->in(1);
1232     // Check final part of MIN tree
1233     if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
1234         y->in(2)->is_Con() ) {
1235       const Type *t = y->in(2)->bottom_type();
1236       if( t == Type::TOP ) return NULL;  // No progress
1237       y_off = t->is_int()->get_con();
1238       y = y->in(1);
1239     }
1240 
1241     if( x->_idx > y->_idx )
1242       return new MinINode(r->in(1),phase->transform(new MinINode(l,r->in(2))));
1243 
1244     // Transform MIN2(x + c0, MIN2(x + c1, z)) into MIN2(x + MIN2(c0, c1), z)
1245     // if x == y and the additions can't overflow.
1246     if (x == y && tx != NULL &&
1247         !can_overflow(tx, x_off) &&
1248         !can_overflow(tx, y_off)) {
1249       return new MinINode(phase->transform(new AddINode(x, phase->intcon(MIN2(x_off, y_off)))), r->in(2));
1250     }
1251   } else {
1252     // Transform MIN2(x + c0, y + c1) into x + MIN2(c0, c1)
1253     // if x == y and the additions can't overflow.
1254     if (x == y && tx != NULL &&
1255         !can_overflow(tx, x_off) &&
1256         !can_overflow(tx, y_off)) {
1257       return new AddINode(x,phase->intcon(MIN2(x_off,y_off)));
1258     }
1259   }
1260   return NULL;
1261 }
1262 
1263 //------------------------------add_ring---------------------------------------
1264 // Supplied function returns the sum of the inputs.
1265 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
1266   const TypeInt *r0 = t0->is_int(); // Handy access
1267   const TypeInt *r1 = t1->is_int();
1268 
1269   // Otherwise just MIN them bits.
1270   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1271 }
1272 
1273 //------------------------------add_ring---------------------------------------
1274 const Type *MinFNode::add_ring( const Type *t0, const Type *t1 ) const {
1275   const TypeF *r0 = t0->is_float_constant();
1276   const TypeF *r1 = t1->is_float_constant();
1277 
1278   if (r0->is_nan()) {
1279     return r0;
1280   }
1281   if (r1->is_nan()) {
1282     return r1;
1283   }
1284 
1285   float f0 = r0->getf();
1286   float f1 = r1->getf();
1287   if (f0 != 0.0f || f1 != 0.0f) {
1288     return f0 < f1 ? r0 : r1;
1289   }
1290 
1291   // handle min of 0.0, -0.0 case.
1292   return (jint_cast(f0) < jint_cast(f1)) ? r0 : r1;
1293 }
1294 
1295 //------------------------------add_ring---------------------------------------
1296 const Type *MinDNode::add_ring( const Type *t0, const Type *t1 ) const {
1297   const TypeD *r0 = t0->is_double_constant();
1298   const TypeD *r1 = t1->is_double_constant();
1299 
1300   if (r0->is_nan()) {
1301     return r0;
1302   }
1303   if (r1->is_nan()) {
1304     return r1;
1305   }
1306 
1307   double d0 = r0->getd();
1308   double d1 = r1->getd();
1309   if (d0 != 0.0 || d1 != 0.0) {
1310     return d0 < d1 ? r0 : r1;
1311   }
1312 
1313   // handle min of 0.0, -0.0 case.
1314   return (jlong_cast(d0) < jlong_cast(d1)) ? r0 : r1;
1315 }
1316 
1317 //------------------------------add_ring---------------------------------------
1318 const Type *MaxFNode::add_ring( const Type *t0, const Type *t1 ) const {
1319   const TypeF *r0 = t0->is_float_constant();
1320   const TypeF *r1 = t1->is_float_constant();
1321 
1322   if (r0->is_nan()) {
1323     return r0;
1324   }
1325   if (r1->is_nan()) {
1326     return r1;
1327   }
1328 
1329   float f0 = r0->getf();
1330   float f1 = r1->getf();
1331   if (f0 != 0.0f || f1 != 0.0f) {
1332     return f0 > f1 ? r0 : r1;
1333   }
1334 
1335   // handle max of 0.0,-0.0 case.
1336   return (jint_cast(f0) > jint_cast(f1)) ? r0 : r1;
1337 }
1338 
1339 //------------------------------add_ring---------------------------------------
1340 const Type *MaxDNode::add_ring( const Type *t0, const Type *t1 ) const {
1341   const TypeD *r0 = t0->is_double_constant();
1342   const TypeD *r1 = t1->is_double_constant();
1343 
1344   if (r0->is_nan()) {
1345     return r0;
1346   }
1347   if (r1->is_nan()) {
1348     return r1;
1349   }
1350 
1351   double d0 = r0->getd();
1352   double d1 = r1->getd();
1353   if (d0 != 0.0 || d1 != 0.0) {
1354     return d0 > d1 ? r0 : r1;
1355   }
1356 
1357   // handle max of 0.0, -0.0 case.
1358   return (jlong_cast(d0) > jlong_cast(d1)) ? r0 : r1;
1359 }