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/cfgnode.hpp"
  29 #include "opto/connode.hpp"
  30 #include "opto/machnode.hpp"
  31 #include "opto/mulnode.hpp"
  32 #include "opto/phaseX.hpp"
  33 #include "opto/subnode.hpp"
  34 
  35 // Portions of code courtesy of Clifford Click
  36 
  37 // Classic Add functionality.  This covers all the usual 'add' behaviors for
  38 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are
  39 // all inherited from this class.  The various identity values are supplied
  40 // by virtual functions.
  41 
  42 
  43 //=============================================================================
  44 //------------------------------hash-------------------------------------------
  45 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap
  46 // (commute) inputs to AddNodes willy-nilly so the hash function must return
  47 // the same value in the presence of edge swapping.
  48 uint AddNode::hash() const {
  49   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  50 }
  51 
  52 //------------------------------Identity---------------------------------------
  53 // If either input is a constant 0, return the other input.
  54 Node *AddNode::Identity( PhaseTransform *phase ) {
  55   const Type *zero = add_id();  // The additive identity
  56   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
  57   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
  58   return this;
  59 }
  60 
  61 //------------------------------commute----------------------------------------
  62 // Commute operands to move loads and constants to the right.
  63 static bool commute( Node *add, int con_left, int con_right ) {
  64   Node *in1 = add->in(1);
  65   Node *in2 = add->in(2);
  66 
  67   // Convert "1+x" into "x+1".
  68   // Right is a constant; leave it
  69   if( con_right ) return false;
  70   // Left is a constant; move it right.
  71   if( con_left ) {
  72     add->swap_edges(1, 2);
  73     return true;
  74   }
  75 
  76   // Convert "Load+x" into "x+Load".
  77   // Now check for loads
  78   if (in2->is_Load()) {
  79     if (!in1->is_Load()) {
  80       // already x+Load to return
  81       return false;
  82     }
  83     // both are loads, so fall through to sort inputs by idx
  84   } else if( in1->is_Load() ) {
  85     // Left is a Load and Right is not; move it right.
  86     add->swap_edges(1, 2);
  87     return true;
  88   }
  89 
  90   PhiNode *phi;
  91   // Check for tight loop increments: Loop-phi of Add of loop-phi
  92   if( in1->is_Phi() && (phi = in1->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add)
  93     return false;
  94   if( in2->is_Phi() && (phi = in2->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add){
  95     add->swap_edges(1, 2);
  96     return true;
  97   }
  98 
  99   // Otherwise, sort inputs (commutativity) to help value numbering.
 100   if( in1->_idx > in2->_idx ) {
 101     add->swap_edges(1, 2);
 102     return true;
 103   }
 104   return false;
 105 }
 106 
 107 //------------------------------Idealize---------------------------------------
 108 // If we get here, we assume we are associative!
 109 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 110   const Type *t1 = phase->type( in(1) );
 111   const Type *t2 = phase->type( in(2) );
 112   int con_left  = t1->singleton();
 113   int con_right = t2->singleton();
 114 
 115   // Check for commutative operation desired
 116   if( commute(this,con_left,con_right) ) return this;
 117 
 118   AddNode *progress = NULL;             // Progress flag
 119 
 120   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a
 121   // constant, and the left input is an add of a constant, flatten the
 122   // expression tree.
 123   Node *add1 = in(1);
 124   Node *add2 = in(2);
 125   int add1_op = add1->Opcode();
 126   int this_op = Opcode();
 127   if( con_right && t2 != Type::TOP && // Right input is a constant?
 128       add1_op == this_op ) { // Left input is an Add?
 129 
 130     // Type of left _in right input
 131     const Type *t12 = phase->type( add1->in(2) );
 132     if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
 133       // Check for rare case of closed data cycle which can happen inside
 134       // unreachable loops. In these cases the computation is undefined.
 135 #ifdef ASSERT
 136       Node *add11    = add1->in(1);
 137       int   add11_op = add11->Opcode();
 138       if( (add1 == add1->in(1))
 139          || (add11_op == this_op && add11->in(1) == add1) ) {
 140         assert(false, "dead loop in AddNode::Ideal");
 141       }
 142 #endif
 143       // The Add of the flattened expression
 144       Node *x1 = add1->in(1);
 145       Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));
 146       PhaseIterGVN *igvn = phase->is_IterGVN();
 147       if( igvn ) {
 148         set_req_X(2,x2,igvn);
 149         set_req_X(1,x1,igvn);
 150       } else {
 151         set_req(2,x2);
 152         set_req(1,x1);
 153       }
 154       progress = this;            // Made progress
 155       add1 = in(1);
 156       add1_op = add1->Opcode();
 157     }
 158   }
 159 
 160   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.
 161   if( add1_op == this_op && !con_right ) {
 162     Node *a12 = add1->in(2);
 163     const Type *t12 = phase->type( a12 );
 164     if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
 165        !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {
 166       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
 167       add2 = add1->clone();
 168       add2->set_req(2, in(2));
 169       add2 = phase->transform(add2);
 170       set_req(1, add2);
 171       set_req(2, a12);
 172       progress = this;
 173       add2 = a12;
 174     }
 175   }
 176 
 177   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.
 178   int add2_op = add2->Opcode();
 179   if( add2_op == this_op && !con_left ) {
 180     Node *a22 = add2->in(2);
 181     const Type *t22 = phase->type( a22 );
 182     if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
 183        !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {
 184       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
 185       Node *addx = add2->clone();
 186       addx->set_req(1, in(1));
 187       addx->set_req(2, add2->in(1));
 188       addx = phase->transform(addx);
 189       set_req(1, addx);
 190       set_req(2, a22);
 191       progress = this;
 192       PhaseIterGVN *igvn = phase->is_IterGVN();
 193       if (add2->outcnt() == 0 && igvn) {
 194         // add disconnected.
 195         igvn->_worklist.push(add2);
 196       }
 197     }
 198   }
 199 
 200   return progress;
 201 }
 202 
 203 //------------------------------Value-----------------------------------------
 204 // An add node sums it's two _in.  If one input is an RSD, we must mixin
 205 // the other input's symbols.
 206 const Type *AddNode::Value( PhaseTransform *phase ) const {
 207   // Either input is TOP ==> the result is TOP
 208   const Type *t1 = phase->type( in(1) );
 209   const Type *t2 = phase->type( in(2) );
 210   if( t1 == Type::TOP ) return Type::TOP;
 211   if( t2 == Type::TOP ) return Type::TOP;
 212 
 213   // Either input is BOTTOM ==> the result is the local BOTTOM
 214   const Type *bot = bottom_type();
 215   if( (t1 == bot) || (t2 == bot) ||
 216       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 217     return bot;
 218 
 219   // Check for an addition involving the additive identity
 220   const Type *tadd = add_of_identity( t1, t2 );
 221   if( tadd ) return tadd;
 222 
 223   return add_ring(t1,t2);               // Local flavor of type addition
 224 }
 225 
 226 //------------------------------add_identity-----------------------------------
 227 // Check for addition of the identity
 228 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 229   const Type *zero = add_id();  // The additive identity
 230   if( t1->higher_equal( zero ) ) return t2;
 231   if( t2->higher_equal( zero ) ) return t1;
 232 
 233   return NULL;
 234 }
 235 
 236 
 237 //=============================================================================
 238 //------------------------------Idealize---------------------------------------
 239 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 240   Node* in1 = in(1);
 241   Node* in2 = in(2);
 242   int op1 = in1->Opcode();
 243   int op2 = in2->Opcode();
 244   // Fold (con1-x)+con2 into (con1+con2)-x
 245   if ( op1 == Op_AddI && op2 == Op_SubI ) {
 246     // Swap edges to try optimizations below
 247     in1 = in2;
 248     in2 = in(1);
 249     op1 = op2;
 250     op2 = in2->Opcode();
 251   }
 252   if( op1 == Op_SubI ) {
 253     const Type *t_sub1 = phase->type( in1->in(1) );
 254     const Type *t_2    = phase->type( in2        );
 255     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 256       return new (phase->C) SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 257                               in1->in(2) );
 258     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 259     if( op2 == Op_SubI ) {
 260       // Check for dead cycle: d = (a-b)+(c-d)
 261       assert( in1->in(2) != this && in2->in(2) != this,
 262               "dead loop in AddINode::Ideal" );
 263       Node *sub  = new (phase->C) SubINode(NULL, NULL);
 264       sub->init_req(1, phase->transform(new (phase->C) AddINode(in1->in(1), in2->in(1) ) ));
 265       sub->init_req(2, phase->transform(new (phase->C) AddINode(in1->in(2), in2->in(2) ) ));
 266       return sub;
 267     }
 268     // Convert "(a-b)+(b+c)" into "(a+c)"
 269     if( op2 == Op_AddI && 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) AddINode(in1->in(1), in2->in(2));
 272     }
 273     // Convert "(a-b)+(c+b)" into "(a+c)"
 274     if( op2 == Op_AddI && in1->in(2) == in2->in(2) ) {
 275       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 276       return new (phase->C) AddINode(in1->in(1), in2->in(1));
 277     }
 278     // Convert "(a-b)+(b-c)" into "(a-c)"
 279     if( op2 == Op_SubI && in1->in(2) == in2->in(1) ) {
 280       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
 281       return new (phase->C) SubINode(in1->in(1), in2->in(2));
 282     }
 283     // Convert "(a-b)+(c-a)" into "(c-b)"
 284     if( op2 == Op_SubI && in1->in(1) == in2->in(2) ) {
 285       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
 286       return new (phase->C) SubINode(in2->in(1), in1->in(2));
 287     }
 288   }
 289 
 290   // Convert "x+(0-y)" into "(x-y)"
 291   if( op2 == Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )
 292     return new (phase->C) SubINode(in1, in2->in(2) );
 293 
 294   // Convert "(0-y)+x" into "(x-y)"
 295   if( op1 == Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )
 296     return new (phase->C) SubINode( in2, in1->in(2) );
 297 
 298   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
 299   // Helps with array allocation math constant folding
 300   // See 4790063:
 301   // Unrestricted transformation is unsafe for some runtime values of 'x'
 302   // ( x ==  0, z == 1, y == -1 ) fails
 303   // ( x == -5, z == 1, y ==  1 ) fails
 304   // Transform works for small z and small negative y when the addition
 305   // (x + (y << z)) does not cross zero.
 306   // Implement support for negative y and (x >= -(y << z))
 307   // Have not observed cases where type information exists to support
 308   // positive y and (x <= -(y << z))
 309   if( op1 == Op_URShiftI && op2 == Op_ConI &&
 310       in1->in(2)->Opcode() == Op_ConI ) {
 311     jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
 312     jint y = phase->type( in2 )->is_int()->get_con();
 313 
 314     if( z < 5 && -5 < y && y < 0 ) {
 315       const Type *t_in11 = phase->type(in1->in(1));
 316       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {
 317         Node *a = phase->transform( new (phase->C) AddINode( in1->in(1), phase->intcon(y<<z) ) );
 318         return new (phase->C) URShiftINode( a, in1->in(2) );
 319       }
 320     }
 321   }
 322 
 323   return AddNode::Ideal(phase, can_reshape);
 324 }
 325 
 326 
 327 //------------------------------Identity---------------------------------------
 328 // Fold (x-y)+y  OR  y+(x-y)  into  x
 329 Node *AddINode::Identity( PhaseTransform *phase ) {
 330   if( in(1)->Opcode() == Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {
 331     return in(1)->in(1);
 332   }
 333   else if( in(2)->Opcode() == Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {
 334     return in(2)->in(1);
 335   }
 336   return AddNode::Identity(phase);
 337 }
 338 
 339 
 340 //------------------------------add_ring---------------------------------------
 341 // Supplied function returns the sum of the inputs.  Guaranteed never
 342 // to be passed a TOP or BOTTOM type, these are filtered out by
 343 // pre-check.
 344 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
 345   const TypeInt *r0 = t0->is_int(); // Handy access
 346   const TypeInt *r1 = t1->is_int();
 347   int lo = java_add(r0->_lo, r1->_lo);
 348   int hi = java_add(r0->_hi, r1->_hi);
 349   if( !(r0->is_con() && r1->is_con()) ) {
 350     // Not both constants, compute approximate result
 351     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 352       lo = min_jint; hi = max_jint; // Underflow on the low side
 353     }
 354     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 355       lo = min_jint; hi = max_jint; // Overflow on the high side
 356     }
 357     if( lo > hi ) {               // Handle overflow
 358       lo = min_jint; hi = max_jint;
 359     }
 360   } else {
 361     // both constants, compute precise result using 'lo' and 'hi'
 362     // Semantics define overflow and underflow for integer addition
 363     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 364   }
 365   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 366 }
 367 
 368 
 369 //=============================================================================
 370 //------------------------------Idealize---------------------------------------
 371 Node *AddLNode::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   // Fold (con1-x)+con2 into (con1+con2)-x
 377   if ( op1 == Op_AddL && op2 == Op_SubL ) {
 378     // Swap edges to try optimizations below
 379     in1 = in2;
 380     in2 = in(1);
 381     op1 = op2;
 382     op2 = in2->Opcode();
 383   }
 384   // Fold (con1-x)+con2 into (con1+con2)-x
 385   if( op1 == Op_SubL ) {
 386     const Type *t_sub1 = phase->type( in1->in(1) );
 387     const Type *t_2    = phase->type( in2        );
 388     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
 389       return new (phase->C) SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ),
 390                               in1->in(2) );
 391     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
 392     if( op2 == Op_SubL ) {
 393       // Check for dead cycle: d = (a-b)+(c-d)
 394       assert( in1->in(2) != this && in2->in(2) != this,
 395               "dead loop in AddLNode::Ideal" );
 396       Node *sub  = new (phase->C) SubLNode(NULL, NULL);
 397       sub->init_req(1, phase->transform(new (phase->C) AddLNode(in1->in(1), in2->in(1) ) ));
 398       sub->init_req(2, phase->transform(new (phase->C) AddLNode(in1->in(2), in2->in(2) ) ));
 399       return sub;
 400     }
 401     // Convert "(a-b)+(b+c)" into "(a+c)"
 402     if( op2 == Op_AddL && 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) AddLNode(in1->in(1), in2->in(2));
 405     }
 406     // Convert "(a-b)+(c+b)" into "(a+c)"
 407     if( op2 == Op_AddL && in1->in(2) == in2->in(2) ) {
 408       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 409       return new (phase->C) AddLNode(in1->in(1), in2->in(1));
 410     }
 411     // Convert "(a-b)+(b-c)" into "(a-c)"
 412     if( op2 == Op_SubL && in1->in(2) == in2->in(1) ) {
 413       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
 414       return new (phase->C) SubLNode(in1->in(1), in2->in(2));
 415     }
 416     // Convert "(a-b)+(c-a)" into "(c-b)"
 417     if( op2 == Op_SubL && in1->in(1) == in1->in(2) ) {
 418       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
 419       return new (phase->C) SubLNode(in2->in(1), in1->in(2));
 420     }
 421   }
 422 
 423   // Convert "x+(0-y)" into "(x-y)"
 424   if( op2 == Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )
 425     return new (phase->C) SubLNode( in1, in2->in(2) );
 426 
 427   // Convert "(0-y)+x" into "(x-y)"
 428   if( op1 == Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )
 429     return new (phase->C) SubLNode( in2, in1->in(2) );
 430 
 431   // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"
 432   // into "(X<<1)+Y" and let shift-folding happen.
 433   if( op2 == Op_AddL &&
 434       in2->in(1) == in1 &&
 435       op1 != Op_ConL &&
 436       0 ) {
 437     Node *shift = phase->transform(new (phase->C) LShiftLNode(in1,phase->intcon(1)));
 438     return new (phase->C) AddLNode(shift,in2->in(2));
 439   }
 440 
 441   return AddNode::Ideal(phase, can_reshape);
 442 }
 443 
 444 
 445 //------------------------------Identity---------------------------------------
 446 // Fold (x-y)+y  OR  y+(x-y)  into  x
 447 Node *AddLNode::Identity( PhaseTransform *phase ) {
 448   if( in(1)->Opcode() == Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {
 449     return in(1)->in(1);
 450   }
 451   else if( in(2)->Opcode() == Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {
 452     return in(2)->in(1);
 453   }
 454   return AddNode::Identity(phase);
 455 }
 456 
 457 
 458 //------------------------------add_ring---------------------------------------
 459 // Supplied function returns the sum of the inputs.  Guaranteed never
 460 // to be passed a TOP or BOTTOM type, these are filtered out by
 461 // pre-check.
 462 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
 463   const TypeLong *r0 = t0->is_long(); // Handy access
 464   const TypeLong *r1 = t1->is_long();
 465   jlong lo = java_add(r0->_lo, r1->_lo);
 466   jlong hi = java_add(r0->_hi, r1->_hi);
 467   if( !(r0->is_con() && r1->is_con()) ) {
 468     // Not both constants, compute approximate result
 469     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
 470       lo =min_jlong; hi = max_jlong; // Underflow on the low side
 471     }
 472     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
 473       lo = min_jlong; hi = max_jlong; // Overflow on the high side
 474     }
 475     if( lo > hi ) {               // Handle overflow
 476       lo = min_jlong; hi = max_jlong;
 477     }
 478   } else {
 479     // both constants, compute precise result using 'lo' and 'hi'
 480     // Semantics define overflow and underflow for integer addition
 481     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0
 482   }
 483   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
 484 }
 485 
 486 
 487 //=============================================================================
 488 //------------------------------add_of_identity--------------------------------
 489 // Check for addition of the identity
 490 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 491   // x ADD 0  should return x unless 'x' is a -zero
 492   //
 493   // const Type *zero = add_id();     // The additive identity
 494   // jfloat f1 = t1->getf();
 495   // jfloat f2 = t2->getf();
 496   //
 497   // if( t1->higher_equal( zero ) ) return t2;
 498   // if( t2->higher_equal( zero ) ) return t1;
 499 
 500   return NULL;
 501 }
 502 
 503 //------------------------------add_ring---------------------------------------
 504 // Supplied function returns the sum of the inputs.
 505 // This also type-checks the inputs for sanity.  Guaranteed never to
 506 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 507 const Type *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {
 508   // We must be adding 2 float constants.
 509   return TypeF::make( t0->getf() + t1->getf() );
 510 }
 511 
 512 //------------------------------Ideal------------------------------------------
 513 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 514   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 515     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 516   }
 517 
 518   // Floating point additions are not associative because of boundary conditions (infinity)
 519   return commute(this,
 520                  phase->type( in(1) )->singleton(),
 521                  phase->type( in(2) )->singleton() ) ? this : NULL;
 522 }
 523 
 524 
 525 //=============================================================================
 526 //------------------------------add_of_identity--------------------------------
 527 // Check for addition of the identity
 528 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {
 529   // x ADD 0  should return x unless 'x' is a -zero
 530   //
 531   // const Type *zero = add_id();     // The additive identity
 532   // jfloat f1 = t1->getf();
 533   // jfloat f2 = t2->getf();
 534   //
 535   // if( t1->higher_equal( zero ) ) return t2;
 536   // if( t2->higher_equal( zero ) ) return t1;
 537 
 538   return NULL;
 539 }
 540 //------------------------------add_ring---------------------------------------
 541 // Supplied function returns the sum of the inputs.
 542 // This also type-checks the inputs for sanity.  Guaranteed never to
 543 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 544 const Type *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {
 545   // We must be adding 2 double constants.
 546   return TypeD::make( t0->getd() + t1->getd() );
 547 }
 548 
 549 //------------------------------Ideal------------------------------------------
 550 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 551   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
 552     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms
 553   }
 554 
 555   // Floating point additions are not associative because of boundary conditions (infinity)
 556   return commute(this,
 557                  phase->type( in(1) )->singleton(),
 558                  phase->type( in(2) )->singleton() ) ? this : NULL;
 559 }
 560 
 561 
 562 //=============================================================================
 563 //------------------------------Identity---------------------------------------
 564 // If one input is a constant 0, return the other input.
 565 Node *AddPNode::Identity( PhaseTransform *phase ) {
 566   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;
 567 }
 568 
 569 //------------------------------Idealize---------------------------------------
 570 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 571   // Bail out if dead inputs
 572   if( phase->type( in(Address) ) == Type::TOP ) return NULL;
 573 
 574   // If the left input is an add of a constant, flatten the expression tree.
 575   const Node *n = in(Address);
 576   if (n->is_AddP() && n->in(Base) == in(Base)) {
 577     const AddPNode *addp = n->as_AddP(); // Left input is an AddP
 578     assert( !addp->in(Address)->is_AddP() ||
 579              addp->in(Address)->as_AddP() != addp,
 580             "dead loop in AddPNode::Ideal" );
 581     // Type of left input's right input
 582     const Type *t = phase->type( addp->in(Offset) );
 583     if( t == Type::TOP ) return NULL;
 584     const TypeX *t12 = t->is_intptr_t();
 585     if( t12->is_con() ) {       // Left input is an add of a constant?
 586       // If the right input is a constant, combine constants
 587       const Type *temp_t2 = phase->type( in(Offset) );
 588       if( temp_t2 == Type::TOP ) return NULL;
 589       const TypeX *t2 = temp_t2->is_intptr_t();
 590       Node* address;
 591       Node* offset;
 592       if( t2->is_con() ) {
 593         // The Add of the flattened expression
 594         address = addp->in(Address);
 595         offset  = phase->MakeConX(t2->get_con() + t12->get_con());
 596       } else {
 597         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)
 598         address = phase->transform(new (phase->C) AddPNode(in(Base),addp->in(Address),in(Offset)));
 599         offset  = addp->in(Offset);
 600       }
 601       PhaseIterGVN *igvn = phase->is_IterGVN();
 602       if( igvn ) {
 603         set_req_X(Address,address,igvn);
 604         set_req_X(Offset,offset,igvn);
 605       } else {
 606         set_req(Address,address);
 607         set_req(Offset,offset);
 608       }
 609       return this;
 610     }
 611   }
 612 
 613   // Raw pointers?
 614   if( in(Base)->bottom_type() == Type::TOP ) {
 615     // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.
 616     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
 617       Node* offset = in(Offset);
 618       return new (phase->C) CastX2PNode(offset);
 619     }
 620   }
 621 
 622   // If the right is an add of a constant, push the offset down.
 623   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
 624   // The idea is to merge array_base+scaled_index groups together,
 625   // and only have different constant offsets from the same base.
 626   const Node *add = in(Offset);
 627   if( add->Opcode() == Op_AddX && add->in(1) != add ) {
 628     const Type *t22 = phase->type( add->in(2) );
 629     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?
 630       set_req(Address, phase->transform(new (phase->C) AddPNode(in(Base),in(Address),add->in(1))));
 631       set_req(Offset, add->in(2));
 632       PhaseIterGVN *igvn = phase->is_IterGVN();
 633       if (add->outcnt() == 0 && igvn) {
 634         // add disconnected.
 635         igvn->_worklist.push((Node*)add);
 636       }
 637       return this;              // Made progress
 638     }
 639   }
 640 
 641   return NULL;                  // No progress
 642 }
 643 
 644 //------------------------------bottom_type------------------------------------
 645 // Bottom-type is the pointer-type with unknown offset.
 646 const Type *AddPNode::bottom_type() const {
 647   if (in(Address) == NULL)  return TypePtr::BOTTOM;
 648   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
 649   if( !tp ) return Type::TOP;   // TOP input means TOP output
 650   assert( in(Offset)->Opcode() != Op_ConP, "" );
 651   const Type *t = in(Offset)->bottom_type();
 652   if( t == Type::TOP )
 653     return tp->add_offset(Type::OffsetTop);
 654   const TypeX *tx = t->is_intptr_t();
 655   intptr_t txoffset = Type::OffsetBot;
 656   if (tx->is_con()) {   // Left input is an add of a constant?
 657     txoffset = tx->get_con();
 658   }
 659   return tp->add_offset(txoffset);
 660 }
 661 
 662 //------------------------------Value------------------------------------------
 663 const Type *AddPNode::Value( PhaseTransform *phase ) const {
 664   // Either input is TOP ==> the result is TOP
 665   const Type *t1 = phase->type( in(Address) );
 666   const Type *t2 = phase->type( in(Offset) );
 667   if( t1 == Type::TOP ) return Type::TOP;
 668   if( t2 == Type::TOP ) return Type::TOP;
 669 
 670   // Left input is a pointer
 671   const TypePtr *p1 = t1->isa_ptr();
 672   // Right input is an int
 673   const TypeX *p2 = t2->is_intptr_t();
 674   // Add 'em
 675   intptr_t p2offset = Type::OffsetBot;
 676   if (p2->is_con()) {   // Left input is an add of a constant?
 677     p2offset = p2->get_con();
 678   }
 679   return p1->add_offset(p2offset);
 680 }
 681 
 682 //------------------------Ideal_base_and_offset--------------------------------
 683 // Split an oop pointer into a base and offset.
 684 // (The offset might be Type::OffsetBot in the case of an array.)
 685 // Return the base, or NULL if failure.
 686 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseTransform* phase,
 687                                       // second return value:
 688                                       intptr_t& offset) {
 689   if (ptr->is_AddP()) {
 690     Node* base = ptr->in(AddPNode::Base);
 691     Node* addr = ptr->in(AddPNode::Address);
 692     Node* offs = ptr->in(AddPNode::Offset);
 693     if (base == addr || base->is_top()) {
 694       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);
 695       if (offset != Type::OffsetBot) {
 696         return addr;
 697       }
 698     }
 699   }
 700   offset = Type::OffsetBot;
 701   return NULL;
 702 }
 703 
 704 //------------------------------unpack_offsets----------------------------------
 705 // Collect the AddP offset values into the elements array, giving up
 706 // if there are more than length.
 707 int AddPNode::unpack_offsets(Node* elements[], int length) {
 708   int count = 0;
 709   Node* addr = this;
 710   Node* base = addr->in(AddPNode::Base);
 711   while (addr->is_AddP()) {
 712     if (addr->in(AddPNode::Base) != base) {
 713       // give up
 714       return -1;
 715     }
 716     elements[count++] = addr->in(AddPNode::Offset);
 717     if (count == length) {
 718       // give up
 719       return -1;
 720     }
 721     addr = addr->in(AddPNode::Address);
 722   }
 723   if (addr != base) {
 724     return -1;
 725   }
 726   return count;
 727 }
 728 
 729 //------------------------------match_edge-------------------------------------
 730 // Do we Match on this edge index or not?  Do not match base pointer edge
 731 uint AddPNode::match_edge(uint idx) const {
 732   return idx > Base;
 733 }
 734 
 735 //=============================================================================
 736 //------------------------------Identity---------------------------------------
 737 Node *OrINode::Identity( PhaseTransform *phase ) {
 738   // x | x => x
 739   if (phase->eqv(in(1), in(2))) {
 740     return in(1);
 741   }
 742 
 743   return AddNode::Identity(phase);
 744 }
 745 
 746 //------------------------------add_ring---------------------------------------
 747 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 748 // the logical operations the ring's ADD is really a logical OR function.
 749 // This also type-checks the inputs for sanity.  Guaranteed never to
 750 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 751 const Type *OrINode::add_ring( const Type *t0, const Type *t1 ) const {
 752   const TypeInt *r0 = t0->is_int(); // Handy access
 753   const TypeInt *r1 = t1->is_int();
 754 
 755   // If both args are bool, can figure out better types
 756   if ( r0 == TypeInt::BOOL ) {
 757     if ( r1 == TypeInt::ONE) {
 758       return TypeInt::ONE;
 759     } else if ( r1 == TypeInt::BOOL ) {
 760       return TypeInt::BOOL;
 761     }
 762   } else if ( r0 == TypeInt::ONE ) {
 763     if ( r1 == TypeInt::BOOL ) {
 764       return TypeInt::ONE;
 765     }
 766   }
 767 
 768   // If either input is not a constant, just return all integers.
 769   if( !r0->is_con() || !r1->is_con() )
 770     return TypeInt::INT;        // Any integer, but still no symbols.
 771 
 772   // Otherwise just OR them bits.
 773   return TypeInt::make( r0->get_con() | r1->get_con() );
 774 }
 775 
 776 //=============================================================================
 777 //------------------------------Identity---------------------------------------
 778 Node *OrLNode::Identity( PhaseTransform *phase ) {
 779   // x | x => x
 780   if (phase->eqv(in(1), in(2))) {
 781     return in(1);
 782   }
 783 
 784   return AddNode::Identity(phase);
 785 }
 786 
 787 //------------------------------add_ring---------------------------------------
 788 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {
 789   const TypeLong *r0 = t0->is_long(); // Handy access
 790   const TypeLong *r1 = t1->is_long();
 791 
 792   // If either input is not a constant, just return all integers.
 793   if( !r0->is_con() || !r1->is_con() )
 794     return TypeLong::LONG;      // Any integer, but still no symbols.
 795 
 796   // Otherwise just OR them bits.
 797   return TypeLong::make( r0->get_con() | r1->get_con() );
 798 }
 799 
 800 //=============================================================================
 801 //------------------------------add_ring---------------------------------------
 802 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For
 803 // the logical operations the ring's ADD is really a logical OR function.
 804 // This also type-checks the inputs for sanity.  Guaranteed never to
 805 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 806 const Type *XorINode::add_ring( const Type *t0, const Type *t1 ) const {
 807   const TypeInt *r0 = t0->is_int(); // Handy access
 808   const TypeInt *r1 = t1->is_int();
 809 
 810   // Complementing a boolean?
 811   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE
 812                                || r1 == TypeInt::BOOL))
 813     return TypeInt::BOOL;
 814 
 815   if( !r0->is_con() || !r1->is_con() ) // Not constants
 816     return TypeInt::INT;        // Any integer, but still no symbols.
 817 
 818   // Otherwise just XOR them bits.
 819   return TypeInt::make( r0->get_con() ^ r1->get_con() );
 820 }
 821 
 822 //=============================================================================
 823 //------------------------------add_ring---------------------------------------
 824 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {
 825   const TypeLong *r0 = t0->is_long(); // Handy access
 826   const TypeLong *r1 = t1->is_long();
 827 
 828   // If either input is not a constant, just return all integers.
 829   if( !r0->is_con() || !r1->is_con() )
 830     return TypeLong::LONG;      // Any integer, but still no symbols.
 831 
 832   // Otherwise just OR them bits.
 833   return TypeLong::make( r0->get_con() ^ r1->get_con() );
 834 }
 835 
 836 //=============================================================================
 837 //------------------------------add_ring---------------------------------------
 838 // Supplied function returns the sum of the inputs.
 839 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
 840   const TypeInt *r0 = t0->is_int(); // Handy access
 841   const TypeInt *r1 = t1->is_int();
 842 
 843   // Otherwise just MAX them bits.
 844   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 845 }
 846 
 847 // Check if addition of an integer with type 't' and a constant 'c' can overflow
 848 static bool can_overflow(const TypeInt* t, jint c) {
 849   jint t_lo = t->_lo;
 850   jint t_hi = t->_hi;
 851   return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
 852           (c > 0 && (java_add(t_hi, c) < t_hi)));
 853 }
 854 
 855 //=============================================================================
 856 //------------------------------Idealize---------------------------------------
 857 // MINs show up in range-check loop limit calculations.  Look for
 858 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"
 859 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 860   Node *progress = NULL;
 861   // Force a right-spline graph
 862   Node *l = in(1);
 863   Node *r = in(2);
 864   // Transform  MinI1( MinI2(a,b), c)  into  MinI1( a, MinI2(b,c) )
 865   // to force a right-spline graph for the rest of MinINode::Ideal().
 866   if( l->Opcode() == Op_MinI ) {
 867     assert( l != l->in(1), "dead loop in MinINode::Ideal" );
 868     r = phase->transform(new (phase->C) MinINode(l->in(2),r));
 869     l = l->in(1);
 870     set_req(1, l);
 871     set_req(2, r);
 872     return this;
 873   }
 874 
 875   // Get left input & constant
 876   Node *x = l;
 877   jint x_off = 0;
 878   if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
 879       x->in(2)->is_Con() ) {
 880     const Type *t = x->in(2)->bottom_type();
 881     if( t == Type::TOP ) return NULL;  // No progress
 882     x_off = t->is_int()->get_con();
 883     x = x->in(1);
 884   }
 885 
 886   // Scan a right-spline-tree for MINs
 887   Node *y = r;
 888   jint y_off = 0;
 889   // Check final part of MIN tree
 890   if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
 891       y->in(2)->is_Con() ) {
 892     const Type *t = y->in(2)->bottom_type();
 893     if( t == Type::TOP ) return NULL;  // No progress
 894     y_off = t->is_int()->get_con();
 895     y = y->in(1);
 896   }
 897   if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {
 898     swap_edges(1, 2);
 899     return this;
 900   }
 901 
 902   const TypeInt* tx = phase->type(x)->isa_int();
 903 
 904   if( r->Opcode() == Op_MinI ) {
 905     assert( r != r->in(2), "dead loop in MinINode::Ideal" );
 906     y = r->in(1);
 907     // Check final part of MIN tree
 908     if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
 909         y->in(2)->is_Con() ) {
 910       const Type *t = y->in(2)->bottom_type();
 911       if( t == Type::TOP ) return NULL;  // No progress
 912       y_off = t->is_int()->get_con();
 913       y = y->in(1);
 914     }
 915 
 916     if( x->_idx > y->_idx )
 917       return new (phase->C) MinINode(r->in(1),phase->transform(new (phase->C) MinINode(l,r->in(2))));
 918 
 919     // Transform MIN2(x + c0, MIN2(x + c1, z)) into MIN2(x + MIN2(c0, c1), z)
 920     // if x == y and the additions can't overflow.
 921     if (phase->eqv(x,y) && tx != NULL &&
 922         !can_overflow(tx, x_off) &&
 923         !can_overflow(tx, y_off)) {
 924       return new (phase->C) MinINode(phase->transform(new (phase->C) AddINode(x, phase->intcon(MIN2(x_off, y_off)))), r->in(2));
 925     }
 926   } else {
 927     // Transform MIN2(x + c0, y + c1) into x + MIN2(c0, c1)
 928     // if x == y and the additions can't overflow.
 929     if (phase->eqv(x,y) && tx != NULL &&
 930         !can_overflow(tx, x_off) &&
 931         !can_overflow(tx, y_off)) {
 932       return new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)));
 933     }
 934   }
 935   return NULL;
 936 }
 937 
 938 //------------------------------add_ring---------------------------------------
 939 // Supplied function returns the sum of the inputs.
 940 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {
 941   const TypeInt *r0 = t0->is_int(); // Handy access
 942   const TypeInt *r1 = t1->is_int();
 943 
 944   // Otherwise just MIN them bits.
 945   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
 946 }