1 /*
   2  * Copyright (c) 1997, 2012, 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
  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 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.
  22  *
  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/mulnode.hpp"
  33 #include "opto/phaseX.hpp"
  34 #include "opto/subnode.hpp"
  35 
  36 // Portions of code courtesy of Clifford Click
  37 
  38 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  39 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  40 // all inherited from this class.  The various identity values are supplied
  41 // by virtual functions.
  42 
  43 
  44 //=============================================================================
  45 //------------------------------hash-------------------------------------------
  46 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  47 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  48 // the same value in the presence of edge swapping.
  49 uint AddNode::hash() const {
  50   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  51 }
  52 
  53 //------------------------------Identity---------------------------------------
  54 // If either input is a constant 0, return the other input.
  55 Node *AddNode::Identity( PhaseTransform *phase ) {
  56   const Type *zero = add_id();  // The additive identity
  57   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  58   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  59   return this;
  60 }
  61 
  62 //------------------------------commute----------------------------------------
  63 // Commute operands to move loads and constants to the right.
  64 static bool commute( Node *add, int con_left, int con_right ) {
  65   Node *in1 = add->in(1);
  66   Node *in2 = add->in(2);
  67 
  68   // Convert "1+x" into "x+1".
  69   // Right is a constant; leave it
  70   if( con_right ) return false;
  71   // Left is a constant; move it right.
  72   if( con_left ) {
  73     add->swap_edges(1, 2);
  74     return true;
  75   }
  76 
  77   // Convert "Load+x" into "x+Load".
  78   // Now check for loads
  79   if (in2->is_Load()) {
  80     if (!in1->is_Load()) {
  81       // already x+Load to return
  82       return false;
  83     }
  84     // both are loads, so fall through to sort inputs by idx
  85   } else if( in1->is_Load() ) {
  86     // Left is a Load and Right is not; move it right.
  87     add->swap_edges(1, 2);
  88     return true;
  89   }
  90 
  91   PhiNode *phi;
  92   // Check for tight loop increments: Loop-phi of Add of loop-phi
  93   if( in1->is_Phi() && (phi = in1->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add)
  94     return false;
  95   if( in2->is_Phi() && (phi = in2->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add){
  96     add->swap_edges(1, 2);
  97     return true;
  98   }
  99 
 100   // Otherwise, sort inputs (commutativity) to help value numbering.
 101   if( in1->_idx > in2->_idx ) {
 102     add->swap_edges(1, 2);
 103     return true;
 104   }
 105   return false;
 106 }
 107 
 108 //------------------------------Idealize---------------------------------------
 109 // If we get here, we assume we are associative!
 110 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 111   const Type *t1 = phase->type( in(1) );
 112   const Type *t2 = phase->type( in(2) );
 113   int con_left  = t1->singleton();
 114   int con_right = t2->singleton();
 115 
 116   // Check for commutative operation desired
 117   if( commute(this,con_left,con_right) ) return this;
 118 
 119   AddNode *progress = NULL;             // Progress flag
 120 
 121   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 122   // constant, and the left input is an add of a constant, flatten the
 123   // expression tree.
 124   Node *add1 = in(1);
 125   Node *add2 = in(2);
 126   int add1_op = add1->Opcode();
 127   int this_op = Opcode();
 128   if( con_right && t2 != Type::TOP && // Right input is a constant?
 129       add1_op == this_op ) { // Left input is an Add?
 130 
 131     // Type of left _in right input
 132     const Type *t12 = phase->type( add1->in(2) );
 133     if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
 134       // Check for rare case of closed data cycle which can happen inside
 135       // unreachable loops. In these cases the computation is undefined.
 136 #ifdef ASSERT
 137       Node *add11    = add1->in(1);
 138       int   add11_op = add11->Opcode();
 139       if( (add1 == add1->in(1))
 140          || (add11_op == this_op && add11->in(1) == add1) ) {
 141         assert(false, "dead loop in AddNode::Ideal");
 142       }
 143 #endif
 144       // The Add of the flattened expression
 145       Node *x1 = add1->in(1);
 146       Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));
 147       PhaseIterGVN *igvn = phase->is_IterGVN();
 148       if( igvn ) {
 149         set_req_X(2,x2,igvn);
 150         set_req_X(1,x1,igvn);
 151       } else {
 152         set_req(2,x2);
 153         set_req(1,x1);
 154       }
 155       progress = this;            // Made progress
 156       add1 = in(1);
 157       add1_op = add1->Opcode();
 158     }
 159   }
 160 
 161   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 162   if( add1_op == this_op && !con_right ) {
 163     Node *a12 = add1->in(2);
 164     const Type *t12 = phase->type( a12 );
 165     if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 166        !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {
 167       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 168       add2 = add1->clone();
 169       add2->set_req(2, in(2));
 170       add2 = phase->transform(add2);
 171       set_req(1, add2);
 172       set_req(2, a12);
 173       progress = this;
 174       add2 = a12;
 175     }
 176   }
 177 
 178   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 179   int add2_op = add2->Opcode();
 180   if( add2_op == this_op && !con_left ) {
 181     Node *a22 = add2->in(2);
 182     const Type *t22 = phase->type( a22 );
 183     if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 184        !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {
 185       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 186       Node *addx = add2->clone();
 187       addx->set_req(1, in(1));
 188       addx->set_req(2, add2->in(1));
 189       addx = phase->transform(addx);
 190       set_req(1, addx);
 191       set_req(2, a22);
 192       progress = this;
 193       PhaseIterGVN *igvn = phase->is_IterGVN();
 194       if (add2->outcnt() == 0 && igvn) {
 195         // add disconnected.
 196         igvn->_worklist.push(add2);
 197       }
 198     }
 199   }
 200 
 201   return progress;
 202 }
 203 
 204 //------------------------------Value-----------------------------------------
 205 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 206 // the other input's symbols.
 207 const Type *AddNode::Value( PhaseTransform *phase ) const {
 208   // Either input is TOP ==> the result is TOP
 209   const Type *t1 = phase->type( in(1) );
 210   const Type *t2 = phase->type( in(2) );
 211   if( t1 == Type::TOP ) return Type::TOP;
 212   if( t2 == Type::TOP ) return Type::TOP;
 213 
 214   // Either input is BOTTOM ==> the result is the local BOTTOM
 215   const Type *bot = bottom_type();
 216   if( (t1 == bot) || (t2 == bot) ||
 217       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 218     return bot;
 219 
 220   // Check for an addition involving the additive identity
 221   const Type *tadd = add_of_identity( t1, t2 );
 222   if( tadd ) return tadd;
 223 
 224   return add_ring(t1,t2);               // Local flavor of type addition
 225 }
 226 
 227 //------------------------------add_identity-----------------------------------
 228 // Check for addition of the identity
 229 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 230   const Type *zero = add_id();  // The additive identity
 231   if( t1->higher_equal( zero ) ) return t2;
 232   if( t2->higher_equal( zero ) ) return t1;
 233 
 234   return NULL;
 235 }
 236 
 237 
 238 //=============================================================================
 239 //------------------------------Idealize---------------------------------------
 240 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 241   Node* in1 = in(1);
 242   Node* in2 = in(2);
 243   int op1 = in1->Opcode();
 244   int op2 = in2->Opcode();
 245   // Fold (con1-x)+con2 into (con1+con2)-x
 246   if ( op1 == Op_AddI && op2 == Op_SubI ) {
 247     // Swap edges to try optimizations below
 248     in1 = in2;
 249     in2 = in(1);
 250     op1 = op2;
 251     op2 = in2->Opcode();
 252   }
 253   if( op1 == Op_SubI ) {
 254     const Type *t_sub1 = phase->type( in1->in(1) );
 255     const Type *t_2    = phase->type( in2        );
 256     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 257       return new (phase->C) SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 258                               in1->in(2) );
 259     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 260     if( op2 == Op_SubI ) {
 261       // Check for dead cycle: d = (a-b)+(c-d)
 262       assert( in1->in(2) != this && in2->in(2) != this,
 263               "dead loop in AddINode::Ideal" );
 264       Node *sub  = new (phase->C) SubINode(NULL, NULL);
 265       sub->init_req(1, phase->transform(new (phase->C) AddINode(in1->in(1), in2->in(1) ) ));
 266       sub->init_req(2, phase->transform(new (phase->C) AddINode(in1->in(2), in2->in(2) ) ));
 267       return sub;
 268     }
 269     // Convert "(a-b)+(b+c)" into "(a+c)"
 270     if( op2 == Op_AddI && in1->in(2) == in2->in(1) ) {
 271       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
 272       return new (phase->C) AddINode(in1->in(1), in2->in(2));
 273     }
 274     // Convert "(a-b)+(c+b)" into "(a+c)"
 275     if( op2 == Op_AddI && in1->in(2) == in2->in(2) ) {
 276       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 277       return new (phase->C) AddINode(in1->in(1), in2->in(1));
 278     }
 279     // Convert "(a-b)+(b-c)" into "(a-c)"
 280     if( op2 == Op_SubI && in1->in(2) == in2->in(1) ) {
 281       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
 282       return new (phase->C) SubINode(in1->in(1), in2->in(2));
 283     }
 284     // Convert "(a-b)+(c-a)" into "(c-b)"
 285     if( op2 == Op_SubI && in1->in(1) == in2->in(2) ) {
 286       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 287       return new (phase->C) SubINode(in2->in(1), in1->in(2));
 288     }
 289   }
 290 
 291   // Convert "x+(0-y)" into "(x-y)"
 292   if( op2 == Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )
 293     return new (phase->C) SubINode(in1, in2->in(2) );
 294 
 295   // Convert "(0-y)+x" into "(x-y)"
 296   if( op1 == Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )
 297     return new (phase->C) SubINode( in2, in1->in(2) );
 298 
 299   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 300   // Helps with array allocation math constant folding
 301   // See 4790063:
 302   // Unrestricted transformation is unsafe for some runtime values of 'x'
 303   // ( x ==  0, z == 1, y == -1 ) fails
 304   // ( x == -5, z == 1, y ==  1 ) fails
 305   // Transform works for small z and small negative y when the addition
 306   // (x + (y << z)) does not cross zero.
 307   // Implement support for negative y and (x >= -(y << z))
 308   // Have not observed cases where type information exists to support
 309   // positive y and (x <= -(y << z))
 310   if( op1 == Op_URShiftI && op2 == Op_ConI &&
 311       in1->in(2)->Opcode() == Op_ConI ) {
 312     jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 313     jint y = phase->type( in2 )->is_int()->get_con();
 314 
 315     if( z < 5 && -5 < y && y < 0 ) {
 316       const Type *t_in11 = phase->type(in1->in(1));
 317       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {
 318         Node *a = phase->transform( new (phase->C) AddINode( in1->in(1), phase->intcon(y<<z) ) );
 319         return new (phase->C) URShiftINode( a, in1->in(2) );
 320       }
 321     }
 322   }
 323 
 324   return AddNode::Ideal(phase, can_reshape);
 325 }
 326 
 327 
 328 //------------------------------Identity---------------------------------------
 329 // Fold (x-y)+y  OR  y+(x-y)  into  x
 330 Node *AddINode::Identity( PhaseTransform *phase ) {
 331   if( in(1)->Opcode() == Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {
 332     return in(1)->in(1);
 333   }
 334   else if( in(2)->Opcode() == Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {
 335     return in(2)->in(1);
 336   }
 337   return AddNode::Identity(phase);
 338 }
 339 
 340 
 341 //------------------------------add_ring---------------------------------------
 342 // Supplied function returns the sum of the inputs.  Guaranteed never
 343 // to be passed a TOP or BOTTOM type, these are filtered out by
 344 // pre-check.
 345 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 346   const TypeInt *r0 = t0->is_int(); // Handy access
 347   const TypeInt *r1 = t1->is_int();
 348   int lo = r0->_lo + r1->_lo;
 349   int hi = r0->_hi + r1->_hi;
 350   if( !(r0->is_con() && r1->is_con()) ) {
 351     // Not both constants, compute approximate result
 352     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 353       lo = min_jint; hi = max_jint; // Underflow on the low side
 354     }
 355     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 356       lo = min_jint; hi = max_jint; // Overflow on the high side
 357     }
 358     if( lo > hi ) {               // Handle overflow
 359       lo = min_jint; hi = max_jint;
 360     }
 361   } else {
 362     // both constants, compute precise result using 'lo' and 'hi'
 363     // Semantics define overflow and underflow for integer addition
 364     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 365   }
 366   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 367 }
 368 
 369 
 370 //=============================================================================
 371 //------------------------------Idealize---------------------------------------
 372 Node *AddLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 373   Node* in1 = in(1);
 374   Node* in2 = in(2);
 375   int op1 = in1->Opcode();
 376   int op2 = in2->Opcode();
 377   // Fold (con1-x)+con2 into (con1+con2)-x
 378   if ( op1 == Op_AddL && op2 == Op_SubL ) {
 379     // Swap edges to try optimizations below
 380     in1 = in2;
 381     in2 = in(1);
 382     op1 = op2;
 383     op2 = in2->Opcode();
 384   }
 385   // Fold (con1-x)+con2 into (con1+con2)-x
 386   if( op1 == Op_SubL ) {
 387     const Type *t_sub1 = phase->type( in1->in(1) );
 388     const Type *t_2    = phase->type( in2        );
 389     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 390       return new (phase->C) SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 391                               in1->in(2) );
 392     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 393     if( op2 == Op_SubL ) {
 394       // Check for dead cycle: d = (a-b)+(c-d)
 395       assert( in1->in(2) != this && in2->in(2) != this,
 396               "dead loop in AddLNode::Ideal" );
 397       Node *sub  = new (phase->C) SubLNode(NULL, NULL);
 398       sub->init_req(1, phase->transform(new (phase->C) AddLNode(in1->in(1), in2->in(1) ) ));
 399       sub->init_req(2, phase->transform(new (phase->C) AddLNode(in1->in(2), in2->in(2) ) ));
 400       return sub;
 401     }
 402     // Convert "(a-b)+(b+c)" into "(a+c)"
 403     if( op2 == Op_AddL && in1->in(2) == in2->in(1) ) {
 404       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
 405       return new (phase->C) AddLNode(in1->in(1), in2->in(2));
 406     }
 407     // Convert "(a-b)+(c+b)" into "(a+c)"
 408     if( op2 == Op_AddL && in1->in(2) == in2->in(2) ) {
 409       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 410       return new (phase->C) AddLNode(in1->in(1), in2->in(1));
 411     }
 412     // Convert "(a-b)+(b-c)" into "(a-c)"
 413     if( op2 == Op_SubL && in1->in(2) == in2->in(1) ) {
 414       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
 415       return new (phase->C) SubLNode(in1->in(1), in2->in(2));
 416     }
 417     // Convert "(a-b)+(c-a)" into "(c-b)"
 418     if( op2 == Op_SubL && in1->in(1) == in1->in(2) ) {
 419       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 420       return new (phase->C) SubLNode(in2->in(1), in1->in(2));
 421     }
 422   }
 423 
 424   // Convert "x+(0-y)" into "(x-y)"
 425   if( op2 == Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )
 426     return new (phase->C) SubLNode( in1, in2->in(2) );
 427 
 428   // Convert "(0-y)+x" into "(x-y)"
 429   if( op1 == Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )
 430     return new (phase->C) SubLNode( in2, in1->in(2) );
 431 
 432   // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"
 433   // into "(X<<1)+Y" and let shift-folding happen.
 434   if( op2 == Op_AddL &&
 435       in2->in(1) == in1 &&
 436       op1 != Op_ConL &&
 437       0 ) {
 438     Node *shift = phase->transform(new (phase->C) LShiftLNode(in1,phase->intcon(1)));
 439     return new (phase->C) AddLNode(shift,in2->in(2));
 440   }
 441 
 442   return AddNode::Ideal(phase, can_reshape);
 443 }
 444 
 445 
 446 //------------------------------Identity---------------------------------------
 447 // Fold (x-y)+y  OR  y+(x-y)  into  x
 448 Node *AddLNode::Identity( PhaseTransform *phase ) {
 449   if( in(1)->Opcode() == Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {
 450     return in(1)->in(1);
 451   }
 452   else if( in(2)->Opcode() == Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {
 453     return in(2)->in(1);
 454   }
 455   return AddNode::Identity(phase);
 456 }
 457 
 458 
 459 //------------------------------add_ring---------------------------------------
 460 // Supplied function returns the sum of the inputs.  Guaranteed never
 461 // to be passed a TOP or BOTTOM type, these are filtered out by
 462 // pre-check.
 463 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 464   const TypeLong *r0 = t0->is_long(); // Handy access
 465   const TypeLong *r1 = t1->is_long();
 466   jlong lo = r0->_lo + r1->_lo;
 467   jlong hi = r0->_hi + r1->_hi;
 468   if( !(r0->is_con() && r1->is_con()) ) {
 469     // Not both constants, compute approximate result
 470     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 471       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 472     }
 473     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 474       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 475     }
 476     if( lo > hi ) {               // Handle overflow
 477       lo = min_jlong; hi = max_jlong;
 478     }
 479   } else {
 480     // both constants, compute precise result using 'lo' and 'hi'
 481     // Semantics define overflow and underflow for integer addition
 482     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 483   }
 484   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 485 }
 486 
 487 
 488 //=============================================================================
 489 //------------------------------add_of_identity--------------------------------
 490 // Check for addition of the identity
 491 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 492   // x ADD 0  should return x unless 'x' is a -zero
 493   //
 494   // const Type *zero = add_id();     // The additive identity
 495   // jfloat f1 = t1->getf();
 496   // jfloat f2 = t2->getf();
 497   //
 498   // if( t1->higher_equal( zero ) ) return t2;
 499   // if( t2->higher_equal( zero ) ) return t1;
 500 
 501   return NULL;
 502 }
 503 
 504 //------------------------------add_ring---------------------------------------
 505 // Supplied function returns the sum of the inputs.
 506 // This also type-checks the inputs for sanity.  Guaranteed never to
 507 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 508 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 509   // We must be adding 2 float constants.
 510   return TypeF::make( t0->getf() + t1->getf() );
 511 }
 512 
 513 //------------------------------Ideal------------------------------------------
 514 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 515   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 516     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 517   }
 518 
 519   // Floating point additions are not associative because of boundary conditions (infinity)
 520   return commute(this,
 521                  phase->type( in(1) )->singleton(),
 522                  phase->type( in(2) )->singleton() ) ? this : NULL;
 523 }
 524 
 525 
 526 //=============================================================================
 527 //------------------------------add_of_identity--------------------------------
 528 // Check for addition of the identity
 529 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 530   // x ADD 0  should return x unless 'x' is a -zero
 531   //
 532   // const Type *zero = add_id();     // The additive identity
 533   // jfloat f1 = t1->getf();
 534   // jfloat f2 = t2->getf();
 535   //
 536   // if( t1->higher_equal( zero ) ) return t2;
 537   // if( t2->higher_equal( zero ) ) return t1;
 538 
 539   return NULL;
 540 }
 541 //------------------------------add_ring---------------------------------------
 542 // Supplied function returns the sum of the inputs.
 543 // This also type-checks the inputs for sanity.  Guaranteed never to
 544 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 545 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 546   // We must be adding 2 double constants.
 547   return TypeD::make( t0->getd() + t1->getd() );
 548 }
 549 
 550 //------------------------------Ideal------------------------------------------
 551 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 552   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 553     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 554   }
 555 
 556   // Floating point additions are not associative because of boundary conditions (infinity)
 557   return commute(this,
 558                  phase->type( in(1) )->singleton(),
 559                  phase->type( in(2) )->singleton() ) ? this : NULL;
 560 }
 561 
 562 
 563 //=============================================================================
 564 //------------------------------Identity---------------------------------------
 565 // If one input is a constant 0, return the other input.
 566 Node *AddPNode::Identity( PhaseTransform *phase ) {
 567   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 568 }
 569 
 570 //------------------------------Idealize---------------------------------------
 571 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 572   // Bail out if dead inputs
 573   if( phase->type( in(Address) ) == Type::TOP ) return NULL;
 574 
 575   // If the left input is an add of a constant, flatten the expression tree.
 576   const Node *n = in(Address);
 577   if (n->is_AddP() && n->in(Base) == in(Base)) {
 578     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 579     assert( !addp->in(Address)->is_AddP() ||
 580              addp->in(Address)->as_AddP() != addp,
 581             "dead loop in AddPNode::Ideal" );
 582     // Type of left input's right input
 583     const Type *t = phase->type( addp->in(Offset) );
 584     if( t == Type::TOP ) return NULL;
 585     const TypeX *t12 = t->is_intptr_t();
 586     if( t12->is_con() ) {       // Left input is an add of a constant?
 587       // If the right input is a constant, combine constants
 588       const Type *temp_t2 = phase->type( in(Offset) );
 589       if( temp_t2 == Type::TOP ) return NULL;
 590       const TypeX *t2 = temp_t2->is_intptr_t();
 591       Node* address;
 592       Node* offset;
 593       if( t2->is_con() ) {
 594         // The Add of the flattened expression
 595         address = addp->in(Address);
 596         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 597       } else {
 598         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 599         address = phase->transform(new (phase->C) AddPNode(in(Base),addp->in(Address),in(Offset)));
 600         offset  = addp->in(Offset);
 601       }
 602       PhaseIterGVN *igvn = phase->is_IterGVN();
 603       if( igvn ) {
 604         set_req_X(Address,address,igvn);
 605         set_req_X(Offset,offset,igvn);
 606       } else {
 607         set_req(Address,address);
 608         set_req(Offset,offset);
 609       }
 610       return this;
 611     }
 612   }
 613 
 614   // Raw pointers?
 615   if( in(Base)->bottom_type() == Type::TOP ) {
 616     // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.
 617     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
 618       Node* offset = in(Offset);
 619       return new (phase->C) CastX2PNode(offset);
 620     }
 621   }
 622 
 623   // If the right is an add of a constant, push the offset down.
 624   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
 625   // The idea is to merge array_base+scaled_index groups together,
 626   // and only have different constant offsets from the same base.
 627   const Node *add = in(Offset);
 628   if( add->Opcode() == Op_AddX && add->in(1) != add ) {
 629     const Type *t22 = phase->type( add->in(2) );
 630     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?
 631       set_req(Address, phase->transform(new (phase->C) AddPNode(in(Base),in(Address),add->in(1))));
 632       set_req(Offset, add->in(2));
 633       PhaseIterGVN *igvn = phase->is_IterGVN();
 634       if (add->outcnt() == 0 && igvn) {
 635         // add disconnected.
 636         igvn->_worklist.push((Node*)add);
 637       }
 638       return this;              // Made progress
 639     }
 640   }
 641 
 642   return NULL;                  // No progress
 643 }
 644 
 645 //------------------------------bottom_type------------------------------------
 646 // Bottom-type is the pointer-type with unknown offset.
 647 const Type *AddPNode::bottom_type() const {
 648   if (in(Address) == NULL)  return TypePtr::BOTTOM;
 649   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
 650   if( !tp ) return Type::TOP;   // TOP input means TOP output
 651   assert( in(Offset)->Opcode() != Op_ConP, "" );
 652   const Type *t = in(Offset)->bottom_type();
 653   if( t == Type::TOP )
 654     return tp->add_offset(Type::OffsetTop);
 655   const TypeX *tx = t->is_intptr_t();
 656   intptr_t txoffset = Type::OffsetBot;
 657   if (tx->is_con()) {   // Left input is an add of a constant?
 658     txoffset = tx->get_con();
 659   }
 660   return tp->add_offset(txoffset);
 661 }
 662 
 663 //------------------------------Value------------------------------------------
 664 const Type *AddPNode::Value( PhaseTransform *phase ) const {
 665   // Either input is TOP ==> the result is TOP
 666   const Type *t1 = phase->type( in(Address) );
 667   const Type *t2 = phase->type( in(Offset) );
 668   if( t1 == Type::TOP ) return Type::TOP;
 669   if( t2 == Type::TOP ) return Type::TOP;
 670 
 671   // Left input is a pointer
 672   const TypePtr *p1 = t1->isa_ptr();
 673   // Right input is an int
 674   const TypeX *p2 = t2->is_intptr_t();
 675   // Add 'em
 676   intptr_t p2offset = Type::OffsetBot;
 677   if (p2->is_con()) {   // Left input is an add of a constant?
 678     p2offset = p2->get_con();
 679   }
 680   return p1->add_offset(p2offset);
 681 }
 682 
 683 //------------------------Ideal_base_and_offset--------------------------------
 684 // Split an oop pointer into a base and offset.
 685 // (The offset might be Type::OffsetBot in the case of an array.)
 686 // Return the base, or NULL if failure.
 687 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseTransform* phase,
 688                                       // second return value:
 689                                       intptr_t& offset) {
 690   if (ptr->is_AddP()) {
 691     Node* base = ptr->in(AddPNode::Base);
 692     Node* addr = ptr->in(AddPNode::Address);
 693     Node* offs = ptr->in(AddPNode::Offset);
 694     if (base == addr || base->is_top()) {
 695       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 696       if (offset != Type::OffsetBot) {
 697         return addr;
 698       }
 699     }
 700   }
 701   offset = Type::OffsetBot;
 702   return NULL;
 703 }
 704 
 705 //------------------------------unpack_offsets----------------------------------
 706 // Collect the AddP offset values into the elements array, giving up
 707 // if there are more than length.
 708 int AddPNode::unpack_offsets(Node* elements[], int length) {
 709   int count = 0;
 710   Node* addr = this;
 711   Node* base = addr->in(AddPNode::Base);
 712   while (addr->is_AddP()) {
 713     if (addr->in(AddPNode::Base) != base) {
 714       // give up
 715       return -1;
 716     }
 717     elements[count++] = addr->in(AddPNode::Offset);
 718     if (count == length) {
 719       // give up
 720       return -1;
 721     }
 722     addr = addr->in(AddPNode::Address);
 723   }
 724   if (addr != base) {
 725     return -1;
 726   }
 727   return count;
 728 }
 729 
 730 //------------------------------match_edge-------------------------------------
 731 // Do we Match on this edge index or not?  Do not match base pointer edge
 732 uint AddPNode::match_edge(uint idx) const {
 733   return idx > Base;
 734 }
 735 
 736 //=============================================================================
 737 //------------------------------Identity---------------------------------------
 738 Node *OrINode::Identity( PhaseTransform *phase ) {
 739   // x | x => x
 740   if (phase->eqv(in(1), in(2))) {
 741     return in(1);
 742   }
 743 
 744   return AddNode::Identity(phase);
 745 }
 746 
 747 //------------------------------add_ring---------------------------------------
 748 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 749 // the logical operations the ring's ADD is really a logical OR function.
 750 // This also type-checks the inputs for sanity.  Guaranteed never to
 751 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 752 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
 753   const TypeInt *r0 = t0->is_int(); // Handy access
 754   const TypeInt *r1 = t1->is_int();
 755 
 756   // If both args are bool, can figure out better types
 757   if ( r0 == TypeInt::BOOL ) {
 758     if ( r1 == TypeInt::ONE) {
 759       return TypeInt::ONE;
 760     } else if ( r1 == TypeInt::BOOL ) {
 761       return TypeInt::BOOL;
 762     }
 763   } else if ( r0 == TypeInt::ONE ) {
 764     if ( r1 == TypeInt::BOOL ) {
 765       return TypeInt::ONE;
 766     }
 767   }
 768 
 769   // If either input is not a constant, just return all integers.
 770   if( !r0->is_con() || !r1->is_con() )
 771     return TypeInt::INT;        // Any integer, but still no symbols.
 772 
 773   // Otherwise just OR them bits.
 774   return TypeInt::make( r0->get_con() | r1->get_con() );
 775 }
 776 
 777 //=============================================================================
 778 //------------------------------Identity---------------------------------------
 779 Node *OrLNode::Identity( PhaseTransform *phase ) {
 780   // x | x => x
 781   if (phase->eqv(in(1), in(2))) {
 782     return in(1);
 783   }
 784 
 785   return AddNode::Identity(phase);
 786 }
 787 
 788 //------------------------------add_ring---------------------------------------
 789 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
 790   const TypeLong *r0 = t0->is_long(); // Handy access
 791   const TypeLong *r1 = t1->is_long();
 792 
 793   // If either input is not a constant, just return all integers.
 794   if( !r0->is_con() || !r1->is_con() )
 795     return TypeLong::LONG;      // Any integer, but still no symbols.
 796 
 797   // Otherwise just OR them bits.
 798   return TypeLong::make( r0->get_con() | r1->get_con() );
 799 }
 800 
 801 //=============================================================================
 802 //------------------------------add_ring---------------------------------------
 803 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 804 // the logical operations the ring's ADD is really a logical OR function.
 805 // This also type-checks the inputs for sanity.  Guaranteed never to
 806 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 807 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
 808   const TypeInt *r0 = t0->is_int(); // Handy access
 809   const TypeInt *r1 = t1->is_int();
 810 
 811   // Complementing a boolean?
 812   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE
 813                                || r1 == TypeInt::BOOL))
 814     return TypeInt::BOOL;
 815 
 816   if( !r0->is_con() || !r1->is_con() ) // Not constants
 817     return TypeInt::INT;        // Any integer, but still no symbols.
 818 
 819   // Otherwise just XOR them bits.
 820   return TypeInt::make( r0->get_con() ^ r1->get_con() );
 821 }
 822 
 823 //=============================================================================
 824 //------------------------------add_ring---------------------------------------
 825 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
 826   const TypeLong *r0 = t0->is_long(); // Handy access
 827   const TypeLong *r1 = t1->is_long();
 828 
 829   // If either input is not a constant, just return all integers.
 830   if( !r0->is_con() || !r1->is_con() )
 831     return TypeLong::LONG;      // Any integer, but still no symbols.
 832 
 833   // Otherwise just OR them bits.
 834   return TypeLong::make( r0->get_con() ^ r1->get_con() );
 835 }
 836 
 837 //=============================================================================
 838 //------------------------------add_ring---------------------------------------
 839 // Supplied function returns the sum of the inputs.
 840 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
 841   const TypeInt *r0 = t0->is_int(); // Handy access
 842   const TypeInt *r1 = t1->is_int();
 843 
 844   // Otherwise just MAX them bits.
 845   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 846 }
 847 
 848 //=============================================================================
 849 //------------------------------Idealize---------------------------------------
 850 // MINs show up in range-check loop limit calculations.  Look for
 851 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
 852 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 853   Node *progress = NULL;
 854   // Force a right-spline graph
 855   Node *l = in(1);
 856   Node *r = in(2);
 857   // Transform  MinI1( MinI2(a,b), c)  into  MinI1( a, MinI2(b,c) )
 858   // to force a right-spline graph for the rest of MinINode::Ideal().
 859   if( l->Opcode() == Op_MinI ) {
 860     assert( l != l->in(1), "dead loop in MinINode::Ideal" );
 861     r = phase->transform(new (phase->C) MinINode(l->in(2),r));
 862     l = l->in(1);
 863     set_req(1, l);
 864     set_req(2, r);
 865     return this;
 866   }
 867 
 868   // Get left input & constant
 869   Node *x = l;
 870   int x_off = 0;
 871   if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
 872       x->in(2)->is_Con() ) {
 873     const Type *t = x->in(2)->bottom_type();
 874     if( t == Type::TOP ) return NULL;  // No progress
 875     x_off = t->is_int()->get_con();
 876     x = x->in(1);
 877   }
 878 
 879   // Scan a right-spline-tree for MINs
 880   Node *y = r;
 881   int y_off = 0;
 882   // Check final part of MIN tree
 883   if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
 884       y->in(2)->is_Con() ) {
 885     const Type *t = y->in(2)->bottom_type();
 886     if( t == Type::TOP ) return NULL;  // No progress
 887     y_off = t->is_int()->get_con();
 888     y = y->in(1);
 889   }
 890   if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {
 891     swap_edges(1, 2);
 892     return this;
 893   }
 894 
 895 
 896   if( r->Opcode() == Op_MinI ) {
 897     assert( r != r->in(2), "dead loop in MinINode::Ideal" );
 898     y = r->in(1);
 899     // Check final part of MIN tree
 900     if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
 901         y->in(2)->is_Con() ) {
 902       const Type *t = y->in(2)->bottom_type();
 903       if( t == Type::TOP ) return NULL;  // No progress
 904       y_off = t->is_int()->get_con();
 905       y = y->in(1);
 906     }
 907 
 908     if( x->_idx > y->_idx )
 909       return new (phase->C) MinINode(r->in(1),phase->transform(new (phase->C) MinINode(l,r->in(2))));
 910 
 911     // See if covers: MIN2(x+c0,MIN2(y+c1,z))
 912     if( !phase->eqv(x,y) ) return NULL;
 913     // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into
 914     // MIN2(x+c0 or x+c1 which less, z).
 915     return new (phase->C) MinINode(phase->transform(new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));
 916   } else {
 917     // See if covers: MIN2(x+c0,y+c1)
 918     if( !phase->eqv(x,y) ) return NULL;
 919     // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.
 920     return new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)));
 921   }
 922 
 923 }
 924 
 925 //------------------------------add_ring---------------------------------------
 926 // Supplied function returns the sum of the inputs.
 927 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
 928   const TypeInt *r0 = t0->is_int(); // Handy access
 929   const TypeInt *r1 = t1->is_int();
 930 
 931   // Otherwise just MIN them bits.
 932   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 933 }