1 /*
   2  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 // Portions of code courtesy of Clifford Click
  26 
  27 #include "incls/_precompiled.incl"
  28 #include "incls/_addnode.cpp.incl"
  29 
  30 #define MAXFLOAT        ((float)3.40282346638528860e+38)
  31 
  32 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  33 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  34 // all inherited from this class.  The various identity values are supplied
  35 // by virtual functions.
  36 
  37 
  38 //=============================================================================
  39 //------------------------------hash-------------------------------------------
  40 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  41 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  42 // the same value in the presence of edge swapping.
  43 uint AddNode::hash() const {
  44   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  45 }
  46 
  47 //------------------------------Identity---------------------------------------
  48 // If either input is a constant 0, return the other input.
  49 Node *AddNode::Identity( PhaseTransform *phase ) {
  50   const Type *zero = add_id();  // The additive identity
  51   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  52   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  53   return this;
  54 }
  55 
  56 //------------------------------commute----------------------------------------
  57 // Commute operands to move loads and constants to the right.
  58 static bool commute( Node *add, int con_left, int con_right ) {
  59   Node *in1 = add->in(1);
  60   Node *in2 = add->in(2);
  61 
  62   // Convert "1+x" into "x+1".
  63   // Right is a constant; leave it
  64   if( con_right ) return false;
  65   // Left is a constant; move it right.
  66   if( con_left ) {
  67     add->swap_edges(1, 2);
  68     return true;
  69   }
  70 
  71   // Convert "Load+x" into "x+Load".
  72   // Now check for loads
  73   if (in2->is_Load()) {
  74     if (!in1->is_Load()) {
  75       // already x+Load to return
  76       return false;
  77     }
  78     // both are loads, so fall through to sort inputs by idx
  79   } else if( in1->is_Load() ) {
  80     // Left is a Load and Right is not; move it right.
  81     add->swap_edges(1, 2);
  82     return true;
  83   }
  84 
  85   PhiNode *phi;
  86   // Check for tight loop increments: Loop-phi of Add of loop-phi
  87   if( in1->is_Phi() && (phi = in1->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add)
  88     return false;
  89   if( in2->is_Phi() && (phi = in2->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add){
  90     add->swap_edges(1, 2);
  91     return true;
  92   }
  93 
  94   // Otherwise, sort inputs (commutativity) to help value numbering.
  95   if( in1->_idx > in2->_idx ) {
  96     add->swap_edges(1, 2);
  97     return true;
  98   }
  99   return false;
 100 }
 101 
 102 //------------------------------Idealize---------------------------------------
 103 // If we get here, we assume we are associative!
 104 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 105   const Type *t1 = phase->type( in(1) );
 106   const Type *t2 = phase->type( in(2) );
 107   int con_left  = t1->singleton();
 108   int con_right = t2->singleton();
 109 
 110   // Check for commutative operation desired
 111   if( commute(this,con_left,con_right) ) return this;
 112 
 113   AddNode *progress = NULL;             // Progress flag
 114 
 115   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 116   // constant, and the left input is an add of a constant, flatten the
 117   // expression tree.
 118   Node *add1 = in(1);
 119   Node *add2 = in(2);
 120   int add1_op = add1->Opcode();
 121   int this_op = Opcode();
 122   if( con_right && t2 != Type::TOP && // Right input is a constant?
 123       add1_op == this_op ) { // Left input is an Add?
 124 
 125     // Type of left _in right input
 126     const Type *t12 = phase->type( add1->in(2) );
 127     if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
 128       // Check for rare case of closed data cycle which can happen inside
 129       // unreachable loops. In these cases the computation is undefined.
 130 #ifdef ASSERT
 131       Node *add11    = add1->in(1);
 132       int   add11_op = add11->Opcode();
 133       if( (add1 == add1->in(1))
 134          || (add11_op == this_op && add11->in(1) == add1) ) {
 135         assert(false, "dead loop in AddNode::Ideal");
 136       }
 137 #endif
 138       // The Add of the flattened expression
 139       Node *x1 = add1->in(1);
 140       Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));
 141       PhaseIterGVN *igvn = phase->is_IterGVN();
 142       if( igvn ) {
 143         set_req_X(2,x2,igvn);
 144         set_req_X(1,x1,igvn);
 145       } else {
 146         set_req(2,x2);
 147         set_req(1,x1);
 148       }
 149       progress = this;            // Made progress
 150       add1 = in(1);
 151       add1_op = add1->Opcode();
 152     }
 153   }
 154 
 155   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 156   if( add1_op == this_op && !con_right ) {
 157     Node *a12 = add1->in(2);
 158     const Type *t12 = phase->type( a12 );
 159     if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 160        !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {
 161       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 162       add2 = add1->clone();
 163       add2->set_req(2, in(2));
 164       add2 = phase->transform(add2);
 165       set_req(1, add2);
 166       set_req(2, a12);
 167       progress = this;
 168       add2 = a12;
 169     }
 170   }
 171 
 172   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 173   int add2_op = add2->Opcode();
 174   if( add2_op == this_op && !con_left ) {
 175     Node *a22 = add2->in(2);
 176     const Type *t22 = phase->type( a22 );
 177     if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 178        !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {
 179       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 180       Node *addx = add2->clone();
 181       addx->set_req(1, in(1));
 182       addx->set_req(2, add2->in(1));
 183       addx = phase->transform(addx);
 184       set_req(1, addx);
 185       set_req(2, a22);
 186       progress = this;
 187     }
 188   }
 189 
 190   return progress;
 191 }
 192 
 193 //------------------------------Value-----------------------------------------
 194 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 195 // the other input's symbols.
 196 const Type *AddNode::Value( PhaseTransform *phase ) const {
 197   // Either input is TOP ==> the result is TOP
 198   const Type *t1 = phase->type( in(1) );
 199   const Type *t2 = phase->type( in(2) );
 200   if( t1 == Type::TOP ) return Type::TOP;
 201   if( t2 == Type::TOP ) return Type::TOP;
 202 
 203   // Either input is BOTTOM ==> the result is the local BOTTOM
 204   const Type *bot = bottom_type();
 205   if( (t1 == bot) || (t2 == bot) ||
 206       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 207     return bot;
 208 
 209   // Check for an addition involving the additive identity
 210   const Type *tadd = add_of_identity( t1, t2 );
 211   if( tadd ) return tadd;
 212 
 213   return add_ring(t1,t2);               // Local flavor of type addition
 214 }
 215 
 216 //------------------------------add_identity-----------------------------------
 217 // Check for addition of the identity
 218 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 219   const Type *zero = add_id();  // The additive identity
 220   if( t1->higher_equal( zero ) ) return t2;
 221   if( t2->higher_equal( zero ) ) return t1;
 222 
 223   return NULL;
 224 }
 225 
 226 
 227 //=============================================================================
 228 //------------------------------Idealize---------------------------------------
 229 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 230   Node* in1 = in(1);
 231   Node* in2 = in(2);
 232   int op1 = in1->Opcode();
 233   int op2 = in2->Opcode();
 234   // Fold (con1-x)+con2 into (con1+con2)-x
 235   if ( op1 == Op_AddI && op2 == Op_SubI ) {
 236     // Swap edges to try optimizations below
 237     in1 = in2;
 238     in2 = in(1);
 239     op1 = op2;
 240     op2 = in2->Opcode();
 241   }
 242   if( op1 == Op_SubI ) {
 243     const Type *t_sub1 = phase->type( in1->in(1) );
 244     const Type *t_2    = phase->type( in2        );
 245     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 246       return new (phase->C, 3) SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 247                               in1->in(2) );
 248     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 249     if( op2 == Op_SubI ) {
 250       // Check for dead cycle: d = (a-b)+(c-d)
 251       assert( in1->in(2) != this && in2->in(2) != this,
 252               "dead loop in AddINode::Ideal" );
 253       Node *sub  = new (phase->C, 3) SubINode(NULL, NULL);
 254       sub->init_req(1, phase->transform(new (phase->C, 3) AddINode(in1->in(1), in2->in(1) ) ));
 255       sub->init_req(2, phase->transform(new (phase->C, 3) AddINode(in1->in(2), in2->in(2) ) ));
 256       return sub;
 257     }
 258     // Convert "(a-b)+(b+c)" into "(a+c)"
 259     if( op2 == Op_AddI && in1->in(2) == in2->in(1) ) {
 260       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
 261       return new (phase->C, 3) AddINode(in1->in(1), in2->in(2));
 262     }
 263     // Convert "(a-b)+(c+b)" into "(a+c)"
 264     if( op2 == Op_AddI && in1->in(2) == in2->in(2) ) {
 265       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 266       return new (phase->C, 3) AddINode(in1->in(1), in2->in(1));
 267     }
 268     // Convert "(a-b)+(b-c)" into "(a-c)"
 269     if( op2 == Op_SubI && in1->in(2) == in2->in(1) ) {
 270       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
 271       return new (phase->C, 3) SubINode(in1->in(1), in2->in(2));
 272     }
 273     // Convert "(a-b)+(c-a)" into "(c-b)"
 274     if( op2 == Op_SubI && in1->in(1) == in2->in(2) ) {
 275       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 276       return new (phase->C, 3) SubINode(in2->in(1), in1->in(2));
 277     }
 278   }
 279 
 280   // Convert "x+(0-y)" into "(x-y)"
 281   if( op2 == Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )
 282     return new (phase->C, 3) SubINode(in1, in2->in(2) );
 283 
 284   // Convert "(0-y)+x" into "(x-y)"
 285   if( op1 == Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )
 286     return new (phase->C, 3) SubINode( in2, in1->in(2) );
 287 
 288   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 289   // Helps with array allocation math constant folding
 290   // See 4790063:
 291   // Unrestricted transformation is unsafe for some runtime values of 'x'
 292   // ( x ==  0, z == 1, y == -1 ) fails
 293   // ( x == -5, z == 1, y ==  1 ) fails
 294   // Transform works for small z and small negative y when the addition
 295   // (x + (y << z)) does not cross zero.
 296   // Implement support for negative y and (x >= -(y << z))
 297   // Have not observed cases where type information exists to support
 298   // positive y and (x <= -(y << z))
 299   if( op1 == Op_URShiftI && op2 == Op_ConI &&
 300       in1->in(2)->Opcode() == Op_ConI ) {
 301     jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 302     jint y = phase->type( in2 )->is_int()->get_con();
 303 
 304     if( z < 5 && -5 < y && y < 0 ) {
 305       const Type *t_in11 = phase->type(in1->in(1));
 306       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {
 307         Node *a = phase->transform( new (phase->C, 3) AddINode( in1->in(1), phase->intcon(y<<z) ) );
 308         return new (phase->C, 3) URShiftINode( a, in1->in(2) );
 309       }
 310     }
 311   }
 312 
 313   return AddNode::Ideal(phase, can_reshape);
 314 }
 315 
 316 
 317 //------------------------------Identity---------------------------------------
 318 // Fold (x-y)+y  OR  y+(x-y)  into  x
 319 Node *AddINode::Identity( PhaseTransform *phase ) {
 320   if( in(1)->Opcode() == Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {
 321     return in(1)->in(1);
 322   }
 323   else if( in(2)->Opcode() == Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {
 324     return in(2)->in(1);
 325   }
 326   return AddNode::Identity(phase);
 327 }
 328 
 329 
 330 //------------------------------add_ring---------------------------------------
 331 // Supplied function returns the sum of the inputs.  Guaranteed never
 332 // to be passed a TOP or BOTTOM type, these are filtered out by
 333 // pre-check.
 334 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 335   const TypeInt *r0 = t0->is_int(); // Handy access
 336   const TypeInt *r1 = t1->is_int();
 337   int lo = r0->_lo + r1->_lo;
 338   int hi = r0->_hi + r1->_hi;
 339   if( !(r0->is_con() && r1->is_con()) ) {
 340     // Not both constants, compute approximate result
 341     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 342       lo = min_jint; hi = max_jint; // Underflow on the low side
 343     }
 344     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 345       lo = min_jint; hi = max_jint; // Overflow on the high side
 346     }
 347     if( lo > hi ) {               // Handle overflow
 348       lo = min_jint; hi = max_jint;
 349     }
 350   } else {
 351     // both constants, compute precise result using 'lo' and 'hi'
 352     // Semantics define overflow and underflow for integer addition
 353     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 354   }
 355   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 356 }
 357 
 358 
 359 //=============================================================================
 360 //------------------------------Idealize---------------------------------------
 361 Node *AddLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 362   Node* in1 = in(1);
 363   Node* in2 = in(2);
 364   int op1 = in1->Opcode();
 365   int op2 = in2->Opcode();
 366   // Fold (con1-x)+con2 into (con1+con2)-x
 367   if ( op1 == Op_AddL && op2 == Op_SubL ) {
 368     // Swap edges to try optimizations below
 369     in1 = in2;
 370     in2 = in(1);
 371     op1 = op2;
 372     op2 = in2->Opcode();
 373   }
 374   // Fold (con1-x)+con2 into (con1+con2)-x
 375   if( op1 == Op_SubL ) {
 376     const Type *t_sub1 = phase->type( in1->in(1) );
 377     const Type *t_2    = phase->type( in2        );
 378     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 379       return new (phase->C, 3) SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 380                               in1->in(2) );
 381     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 382     if( op2 == Op_SubL ) {
 383       // Check for dead cycle: d = (a-b)+(c-d)
 384       assert( in1->in(2) != this && in2->in(2) != this,
 385               "dead loop in AddLNode::Ideal" );
 386       Node *sub  = new (phase->C, 3) SubLNode(NULL, NULL);
 387       sub->init_req(1, phase->transform(new (phase->C, 3) AddLNode(in1->in(1), in2->in(1) ) ));
 388       sub->init_req(2, phase->transform(new (phase->C, 3) AddLNode(in1->in(2), in2->in(2) ) ));
 389       return sub;
 390     }
 391     // Convert "(a-b)+(b+c)" into "(a+c)"
 392     if( op2 == Op_AddL && in1->in(2) == in2->in(1) ) {
 393       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
 394       return new (phase->C, 3) AddLNode(in1->in(1), in2->in(2));
 395     }
 396     // Convert "(a-b)+(c+b)" into "(a+c)"
 397     if( op2 == Op_AddL && in1->in(2) == in2->in(2) ) {
 398       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 399       return new (phase->C, 3) AddLNode(in1->in(1), in2->in(1));
 400     }
 401     // Convert "(a-b)+(b-c)" into "(a-c)"
 402     if( op2 == Op_SubL && in1->in(2) == in2->in(1) ) {
 403       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
 404       return new (phase->C, 3) SubLNode(in1->in(1), in2->in(2));
 405     }
 406     // Convert "(a-b)+(c-a)" into "(c-b)"
 407     if( op2 == Op_SubL && in1->in(1) == in1->in(2) ) {
 408       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 409       return new (phase->C, 3) SubLNode(in2->in(1), in1->in(2));
 410     }
 411   }
 412 
 413   // Convert "x+(0-y)" into "(x-y)"
 414   if( op2 == Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )
 415     return new (phase->C, 3) SubLNode( in1, in2->in(2) );
 416 
 417   // Convert "(0-y)+x" into "(x-y)"
 418   if( op1 == Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )
 419     return new (phase->C, 3) SubLNode( in2, in1->in(2) );
 420 
 421   // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"
 422   // into "(X<<1)+Y" and let shift-folding happen.
 423   if( op2 == Op_AddL &&
 424       in2->in(1) == in1 &&
 425       op1 != Op_ConL &&
 426       0 ) {
 427     Node *shift = phase->transform(new (phase->C, 3) LShiftLNode(in1,phase->intcon(1)));
 428     return new (phase->C, 3) AddLNode(shift,in2->in(2));
 429   }
 430 
 431   return AddNode::Ideal(phase, can_reshape);
 432 }
 433 
 434 
 435 //------------------------------Identity---------------------------------------
 436 // Fold (x-y)+y  OR  y+(x-y)  into  x
 437 Node *AddLNode::Identity( PhaseTransform *phase ) {
 438   if( in(1)->Opcode() == Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {
 439     return in(1)->in(1);
 440   }
 441   else if( in(2)->Opcode() == Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {
 442     return in(2)->in(1);
 443   }
 444   return AddNode::Identity(phase);
 445 }
 446 
 447 
 448 //------------------------------add_ring---------------------------------------
 449 // Supplied function returns the sum of the inputs.  Guaranteed never
 450 // to be passed a TOP or BOTTOM type, these are filtered out by
 451 // pre-check.
 452 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 453   const TypeLong *r0 = t0->is_long(); // Handy access
 454   const TypeLong *r1 = t1->is_long();
 455   jlong lo = r0->_lo + r1->_lo;
 456   jlong hi = r0->_hi + r1->_hi;
 457   if( !(r0->is_con() && r1->is_con()) ) {
 458     // Not both constants, compute approximate result
 459     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 460       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 461     }
 462     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 463       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 464     }
 465     if( lo > hi ) {               // Handle overflow
 466       lo = min_jlong; hi = max_jlong;
 467     }
 468   } else {
 469     // both constants, compute precise result using 'lo' and 'hi'
 470     // Semantics define overflow and underflow for integer addition
 471     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 472   }
 473   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 474 }
 475 
 476 
 477 //=============================================================================
 478 //------------------------------add_of_identity--------------------------------
 479 // Check for addition of the identity
 480 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 481   // x ADD 0  should return x unless 'x' is a -zero
 482   //
 483   // const Type *zero = add_id();     // The additive identity
 484   // jfloat f1 = t1->getf();
 485   // jfloat f2 = t2->getf();
 486   //
 487   // if( t1->higher_equal( zero ) ) return t2;
 488   // if( t2->higher_equal( zero ) ) return t1;
 489 
 490   return NULL;
 491 }
 492 
 493 //------------------------------add_ring---------------------------------------
 494 // Supplied function returns the sum of the inputs.
 495 // This also type-checks the inputs for sanity.  Guaranteed never to
 496 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 497 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 498   // We must be adding 2 float constants.
 499   return TypeF::make( t0->getf() + t1->getf() );
 500 }
 501 
 502 //------------------------------Ideal------------------------------------------
 503 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 504   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 505     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 506   }
 507 
 508   // Floating point additions are not associative because of boundary conditions (infinity)
 509   return commute(this,
 510                  phase->type( in(1) )->singleton(),
 511                  phase->type( in(2) )->singleton() ) ? this : NULL;
 512 }
 513 
 514 
 515 //=============================================================================
 516 //------------------------------add_of_identity--------------------------------
 517 // Check for addition of the identity
 518 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 519   // x ADD 0  should return x unless 'x' is a -zero
 520   //
 521   // const Type *zero = add_id();     // The additive identity
 522   // jfloat f1 = t1->getf();
 523   // jfloat f2 = t2->getf();
 524   //
 525   // if( t1->higher_equal( zero ) ) return t2;
 526   // if( t2->higher_equal( zero ) ) return t1;
 527 
 528   return NULL;
 529 }
 530 //------------------------------add_ring---------------------------------------
 531 // Supplied function returns the sum of the inputs.
 532 // This also type-checks the inputs for sanity.  Guaranteed never to
 533 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 534 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 535   // We must be adding 2 double constants.
 536   return TypeD::make( t0->getd() + t1->getd() );
 537 }
 538 
 539 //------------------------------Ideal------------------------------------------
 540 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 541   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 542     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 543   }
 544 
 545   // Floating point additions are not associative because of boundary conditions (infinity)
 546   return commute(this,
 547                  phase->type( in(1) )->singleton(),
 548                  phase->type( in(2) )->singleton() ) ? this : NULL;
 549 }
 550 
 551 
 552 //=============================================================================
 553 //------------------------------Identity---------------------------------------
 554 // If one input is a constant 0, return the other input.
 555 Node *AddPNode::Identity( PhaseTransform *phase ) {
 556   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 557 }
 558 
 559 //------------------------------Idealize---------------------------------------
 560 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 561   // Bail out if dead inputs
 562   if( phase->type( in(Address) ) == Type::TOP ) return NULL;
 563 
 564   // If the left input is an add of a constant, flatten the expression tree.
 565   const Node *n = in(Address);
 566   if (n->is_AddP() && n->in(Base) == in(Base)) {
 567     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 568     assert( !addp->in(Address)->is_AddP() ||
 569              addp->in(Address)->as_AddP() != addp,
 570             "dead loop in AddPNode::Ideal" );
 571     // Type of left input's right input
 572     const Type *t = phase->type( addp->in(Offset) );
 573     if( t == Type::TOP ) return NULL;
 574     const TypeX *t12 = t->is_intptr_t();
 575     if( t12->is_con() ) {       // Left input is an add of a constant?
 576       // If the right input is a constant, combine constants
 577       const Type *temp_t2 = phase->type( in(Offset) );
 578       if( temp_t2 == Type::TOP ) return NULL;
 579       const TypeX *t2 = temp_t2->is_intptr_t();
 580       Node* address;
 581       Node* offset;
 582       if( t2->is_con() ) {
 583         // The Add of the flattened expression
 584         address = addp->in(Address);
 585         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 586       } else {
 587         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 588         address = phase->transform(new (phase->C, 4) AddPNode(in(Base),addp->in(Address),in(Offset)));
 589         offset  = addp->in(Offset);
 590       }
 591       PhaseIterGVN *igvn = phase->is_IterGVN();
 592       if( igvn ) {
 593         set_req_X(Address,address,igvn);
 594         set_req_X(Offset,offset,igvn);
 595       } else {
 596         set_req(Address,address);
 597         set_req(Offset,offset);
 598       }
 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 (phase->C, 2) 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 (phase->C, 4) AddPNode(in(Base),in(Address),add->in(1))));
 621       set_req(Offset, add->in(2));
 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   return tp->add_offset(txoffset);
 645 }
 646 
 647 //------------------------------Value------------------------------------------
 648 const Type *AddPNode::Value( PhaseTransform *phase ) const {
 649   // Either input is TOP ==> the result is TOP
 650   const Type *t1 = phase->type( in(Address) );
 651   const Type *t2 = phase->type( in(Offset) );
 652   if( t1 == Type::TOP ) return Type::TOP;
 653   if( t2 == Type::TOP ) return Type::TOP;
 654 
 655   // Left input is a pointer
 656   const TypePtr *p1 = t1->isa_ptr();
 657   // Right input is an int
 658   const TypeX *p2 = t2->is_intptr_t();
 659   // Add 'em
 660   intptr_t p2offset = Type::OffsetBot;
 661   if (p2->is_con()) {   // Left input is an add of a constant?
 662     p2offset = p2->get_con();
 663   }
 664   return p1->add_offset(p2offset);
 665 }
 666 
 667 //------------------------Ideal_base_and_offset--------------------------------
 668 // Split an oop pointer into a base and offset.
 669 // (The offset might be Type::OffsetBot in the case of an array.)
 670 // Return the base, or NULL if failure.
 671 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseTransform* phase,
 672                                       // second return value:
 673                                       intptr_t& offset) {
 674   if (ptr->is_AddP()) {
 675     Node* base = ptr->in(AddPNode::Base);
 676     Node* addr = ptr->in(AddPNode::Address);
 677     Node* offs = ptr->in(AddPNode::Offset);
 678     if (base == addr || base->is_top()) {
 679       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 680       if (offset != Type::OffsetBot) {
 681         return addr;
 682       }
 683     }
 684   }
 685   offset = Type::OffsetBot;
 686   return NULL;
 687 }
 688 
 689 //------------------------------unpack_offsets----------------------------------
 690 // Collect the AddP offset values into the elements array, giving up
 691 // if there are more than length.
 692 int AddPNode::unpack_offsets(Node* elements[], int length) {
 693   int count = 0;
 694   Node* addr = this;
 695   Node* base = addr->in(AddPNode::Base);
 696   while (addr->is_AddP()) {
 697     if (addr->in(AddPNode::Base) != base) {
 698       // give up
 699       return -1;
 700     }
 701     elements[count++] = addr->in(AddPNode::Offset);
 702     if (count == length) {
 703       // give up
 704       return -1;
 705     }
 706     addr = addr->in(AddPNode::Address);
 707   }
 708   return count;
 709 }
 710 
 711 //------------------------------match_edge-------------------------------------
 712 // Do we Match on this edge index or not?  Do not match base pointer edge
 713 uint AddPNode::match_edge(uint idx) const {
 714   return idx > Base;
 715 }
 716 
 717 //---------------------------mach_bottom_type----------------------------------
 718 // Utility function for use by ADLC.  Implements bottom_type for matched AddP.
 719 const Type *AddPNode::mach_bottom_type( const MachNode* n) {
 720   Node* base = n->in(Base);
 721   const Type *t = base->bottom_type();
 722   if ( t == Type::TOP ) {
 723     // an untyped pointer
 724     return TypeRawPtr::BOTTOM;
 725   }
 726   const TypePtr* tp = t->isa_oopptr();
 727   if ( tp == NULL )  return t;
 728   if ( tp->_offset == TypePtr::OffsetBot )  return tp;
 729 
 730   // We must carefully add up the various offsets...
 731   intptr_t offset = 0;
 732   const TypePtr* tptr = NULL;
 733 
 734   uint numopnds = n->num_opnds();
 735   uint index = n->oper_input_base();
 736   for ( uint i = 1; i < numopnds; i++ ) {
 737     MachOper *opnd = n->_opnds[i];
 738     // Check for any interesting operand info.
 739     // In particular, check for both memory and non-memory operands.
 740     // %%%%% Clean this up: use xadd_offset
 741     intptr_t con = opnd->constant();
 742     if ( con == TypePtr::OffsetBot )  goto bottom_out;
 743     offset += con;
 744     con = opnd->constant_disp();
 745     if ( con == TypePtr::OffsetBot )  goto bottom_out;
 746     offset += con;
 747     if( opnd->scale() != 0 ) goto bottom_out;
 748 
 749     // Check each operand input edge.  Find the 1 allowed pointer
 750     // edge.  Other edges must be index edges; track exact constant
 751     // inputs and otherwise assume the worst.
 752     for ( uint j = opnd->num_edges(); j > 0; j-- ) {
 753       Node* edge = n->in(index++);
 754       const Type*    et  = edge->bottom_type();
 755       const TypeX*   eti = et->isa_intptr_t();
 756       if ( eti == NULL ) {
 757         // there must be one pointer among the operands
 758         guarantee(tptr == NULL, "must be only one pointer operand");
 759         if (UseCompressedOops && Universe::narrow_oop_shift() == 0) {
 760           // 32-bits narrow oop can be the base of address expressions
 761           tptr = et->make_ptr()->isa_oopptr();
 762         } else {
 763           // only regular oops are expected here
 764           tptr = et->isa_oopptr();
 765         }
 766         guarantee(tptr != NULL, "non-int operand must be pointer");
 767         if (tptr->higher_equal(tp->add_offset(tptr->offset())))
 768           tp = tptr; // Set more precise type for bailout
 769         continue;
 770       }
 771       if ( eti->_hi != eti->_lo )  goto bottom_out;
 772       offset += eti->_lo;
 773     }
 774   }
 775   guarantee(tptr != NULL, "must be exactly one pointer operand");
 776   return tptr->add_offset(offset);
 777 
 778  bottom_out:
 779   return tp->add_offset(TypePtr::OffsetBot);
 780 }
 781 
 782 //=============================================================================
 783 //------------------------------Identity---------------------------------------
 784 Node *OrINode::Identity( PhaseTransform *phase ) {
 785   // x | x => x
 786   if (phase->eqv(in(1), in(2))) {
 787     return in(1);
 788   }
 789 
 790   return AddNode::Identity(phase);
 791 }
 792 
 793 //------------------------------add_ring---------------------------------------
 794 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 795 // the logical operations the ring's ADD is really a logical OR function.
 796 // This also type-checks the inputs for sanity.  Guaranteed never to
 797 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 798 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
 799   const TypeInt *r0 = t0->is_int(); // Handy access
 800   const TypeInt *r1 = t1->is_int();
 801 
 802   // If both args are bool, can figure out better types
 803   if ( r0 == TypeInt::BOOL ) {
 804     if ( r1 == TypeInt::ONE) {
 805       return TypeInt::ONE;
 806     } else if ( r1 == TypeInt::BOOL ) {
 807       return TypeInt::BOOL;
 808     }
 809   } else if ( r0 == TypeInt::ONE ) {
 810     if ( r1 == TypeInt::BOOL ) {
 811       return TypeInt::ONE;
 812     }
 813   }
 814 
 815   // If either input is not a constant, just return all integers.
 816   if( !r0->is_con() || !r1->is_con() )
 817     return TypeInt::INT;        // Any integer, but still no symbols.
 818 
 819   // Otherwise just OR them bits.
 820   return TypeInt::make( r0->get_con() | r1->get_con() );
 821 }
 822 
 823 //=============================================================================
 824 //------------------------------Identity---------------------------------------
 825 Node *OrLNode::Identity( PhaseTransform *phase ) {
 826   // x | x => x
 827   if (phase->eqv(in(1), in(2))) {
 828     return in(1);
 829   }
 830 
 831   return AddNode::Identity(phase);
 832 }
 833 
 834 //------------------------------add_ring---------------------------------------
 835 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
 836   const TypeLong *r0 = t0->is_long(); // Handy access
 837   const TypeLong *r1 = t1->is_long();
 838 
 839   // If either input is not a constant, just return all integers.
 840   if( !r0->is_con() || !r1->is_con() )
 841     return TypeLong::LONG;      // Any integer, but still no symbols.
 842 
 843   // Otherwise just OR them bits.
 844   return TypeLong::make( r0->get_con() | r1->get_con() );
 845 }
 846 
 847 //=============================================================================
 848 //------------------------------add_ring---------------------------------------
 849 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 850 // the logical operations the ring's ADD is really a logical OR function.
 851 // This also type-checks the inputs for sanity.  Guaranteed never to
 852 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 853 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
 854   const TypeInt *r0 = t0->is_int(); // Handy access
 855   const TypeInt *r1 = t1->is_int();
 856 
 857   // Complementing a boolean?
 858   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE
 859                                || r1 == TypeInt::BOOL))
 860     return TypeInt::BOOL;
 861 
 862   if( !r0->is_con() || !r1->is_con() ) // Not constants
 863     return TypeInt::INT;        // Any integer, but still no symbols.
 864 
 865   // Otherwise just XOR them bits.
 866   return TypeInt::make( r0->get_con() ^ r1->get_con() );
 867 }
 868 
 869 //=============================================================================
 870 //------------------------------add_ring---------------------------------------
 871 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
 872   const TypeLong *r0 = t0->is_long(); // Handy access
 873   const TypeLong *r1 = t1->is_long();
 874 
 875   // If either input is not a constant, just return all integers.
 876   if( !r0->is_con() || !r1->is_con() )
 877     return TypeLong::LONG;      // Any integer, but still no symbols.
 878 
 879   // Otherwise just OR them bits.
 880   return TypeLong::make( r0->get_con() ^ r1->get_con() );
 881 }
 882 
 883 //=============================================================================
 884 //------------------------------add_ring---------------------------------------
 885 // Supplied function returns the sum of the inputs.
 886 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
 887   const TypeInt *r0 = t0->is_int(); // Handy access
 888   const TypeInt *r1 = t1->is_int();
 889 
 890   // Otherwise just MAX them bits.
 891   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 892 }
 893 
 894 //=============================================================================
 895 //------------------------------Idealize---------------------------------------
 896 // MINs show up in range-check loop limit calculations.  Look for
 897 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
 898 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 899   Node *progress = NULL;
 900   // Force a right-spline graph
 901   Node *l = in(1);
 902   Node *r = in(2);
 903   // Transform  MinI1( MinI2(a,b), c)  into  MinI1( a, MinI2(b,c) )
 904   // to force a right-spline graph for the rest of MinINode::Ideal().
 905   if( l->Opcode() == Op_MinI ) {
 906     assert( l != l->in(1), "dead loop in MinINode::Ideal" );
 907     r = phase->transform(new (phase->C, 3) MinINode(l->in(2),r));
 908     l = l->in(1);
 909     set_req(1, l);
 910     set_req(2, r);
 911     return this;
 912   }
 913 
 914   // Get left input & constant
 915   Node *x = l;
 916   int x_off = 0;
 917   if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
 918       x->in(2)->is_Con() ) {
 919     const Type *t = x->in(2)->bottom_type();
 920     if( t == Type::TOP ) return NULL;  // No progress
 921     x_off = t->is_int()->get_con();
 922     x = x->in(1);
 923   }
 924 
 925   // Scan a right-spline-tree for MINs
 926   Node *y = r;
 927   int y_off = 0;
 928   // Check final part of MIN tree
 929   if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
 930       y->in(2)->is_Con() ) {
 931     const Type *t = y->in(2)->bottom_type();
 932     if( t == Type::TOP ) return NULL;  // No progress
 933     y_off = t->is_int()->get_con();
 934     y = y->in(1);
 935   }
 936   if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {
 937     swap_edges(1, 2);
 938     return this;
 939   }
 940 
 941 
 942   if( r->Opcode() == Op_MinI ) {
 943     assert( r != r->in(2), "dead loop in MinINode::Ideal" );
 944     y = r->in(1);
 945     // Check final part of MIN tree
 946     if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
 947         y->in(2)->is_Con() ) {
 948       const Type *t = y->in(2)->bottom_type();
 949       if( t == Type::TOP ) return NULL;  // No progress
 950       y_off = t->is_int()->get_con();
 951       y = y->in(1);
 952     }
 953 
 954     if( x->_idx > y->_idx )
 955       return new (phase->C, 3) MinINode(r->in(1),phase->transform(new (phase->C, 3) MinINode(l,r->in(2))));
 956 
 957     // See if covers: MIN2(x+c0,MIN2(y+c1,z))
 958     if( !phase->eqv(x,y) ) return NULL;
 959     // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into
 960     // MIN2(x+c0 or x+c1 which less, z).
 961     return new (phase->C, 3) MinINode(phase->transform(new (phase->C, 3) AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));
 962   } else {
 963     // See if covers: MIN2(x+c0,y+c1)
 964     if( !phase->eqv(x,y) ) return NULL;
 965     // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.
 966     return new (phase->C, 3) AddINode(x,phase->intcon(MIN2(x_off,y_off)));
 967   }
 968 
 969 }
 970 
 971 //------------------------------add_ring---------------------------------------
 972 // Supplied function returns the sum of the inputs.
 973 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
 974   const TypeInt *r0 = t0->is_int(); // Handy access
 975   const TypeInt *r1 = t1->is_int();
 976 
 977   // Otherwise just MIN them bits.
 978   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 979 }