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/connode.hpp"
  29 #include "opto/memnode.hpp"
  30 #include "opto/mulnode.hpp"
  31 #include "opto/phaseX.hpp"
  32 #include "opto/subnode.hpp"
  33 
  34 // Portions of code courtesy of Clifford Click
  35 
  36 
  37 //=============================================================================
  38 //------------------------------hash-------------------------------------------
  39 // Hash function over MulNodes.  Needs to be commutative; i.e., I swap
  40 // (commute) inputs to MulNodes willy-nilly so the hash function must return
  41 // the same value in the presence of edge swapping.
  42 uint MulNode::hash() const {
  43   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
  44 }
  45 
  46 //------------------------------Identity---------------------------------------
  47 // Multiplying a one preserves the other argument
  48 Node *MulNode::Identity( PhaseTransform *phase ) {
  49   register const Type *one = mul_id();  // The multiplicative identity
  50   if( phase->type( in(1) )->higher_equal( one ) ) return in(2);
  51   if( phase->type( in(2) )->higher_equal( one ) ) return in(1);
  52 
  53   return this;
  54 }
  55 
  56 //------------------------------Ideal------------------------------------------
  57 // We also canonicalize the Node, moving constants to the right input,
  58 // and flatten expressions (so that 1+x+2 becomes x+3).
  59 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  60   const Type *t1 = phase->type( in(1) );
  61   const Type *t2 = phase->type( in(2) );
  62   Node *progress = NULL;        // Progress flag
  63   // We are OK if right is a constant, or right is a load and
  64   // left is a non-constant.
  65   if( !(t2->singleton() ||
  66         (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) {
  67     if( t1->singleton() ||       // Left input is a constant?
  68         // Otherwise, sort inputs (commutativity) to help value numbering.
  69         (in(1)->_idx > in(2)->_idx) ) {
  70       swap_edges(1, 2);
  71       const Type *t = t1;
  72       t1 = t2;
  73       t2 = t;
  74       progress = this;            // Made progress
  75     }
  76   }
  77 
  78   // If the right input is a constant, and the left input is a product of a
  79   // constant, flatten the expression tree.
  80   uint op = Opcode();
  81   if( t2->singleton() &&        // Right input is a constant?
  82       op != Op_MulF &&          // Float & double cannot reassociate
  83       op != Op_MulD ) {
  84     if( t2 == Type::TOP ) return NULL;
  85     Node *mul1 = in(1);
  86 #ifdef ASSERT
  87     // Check for dead loop
  88     int   op1 = mul1->Opcode();
  89     if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) ||
  90         ( op1 == mul_opcode() || op1 == add_opcode() ) &&
  91         ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) ||
  92           phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) )
  93       assert(false, "dead loop in MulNode::Ideal");
  94 #endif
  95 
  96     if( mul1->Opcode() == mul_opcode() ) {  // Left input is a multiply?
  97       // Mul of a constant?
  98       const Type *t12 = phase->type( mul1->in(2) );
  99       if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
 100         // Compute new constant; check for overflow
 101         const Type *tcon01 = ((MulNode*)mul1)->mul_ring(t2,t12);
 102         if( tcon01->singleton() ) {
 103           // The Mul of the flattened expression
 104           set_req(1, mul1->in(1));
 105           set_req(2, phase->makecon( tcon01 ));
 106           t2 = tcon01;
 107           progress = this;      // Made progress
 108         }
 109       }
 110     }
 111     // If the right input is a constant, and the left input is an add of a
 112     // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0
 113     const Node *add1 = in(1);
 114     if( add1->Opcode() == add_opcode() ) {      // Left input is an add?
 115       // Add of a constant?
 116       const Type *t12 = phase->type( add1->in(2) );
 117       if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
 118         assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" );
 119         // Compute new constant; check for overflow
 120         const Type *tcon01 = mul_ring(t2,t12);
 121         if( tcon01->singleton() ) {
 122 
 123         // Convert (X+con1)*con0 into X*con0
 124           Node *mul = clone();    // mul = ()*con0
 125           mul->set_req(1,add1->in(1));  // mul = X*con0
 126           mul = phase->transform(mul);
 127 
 128           Node *add2 = add1->clone();
 129           add2->set_req(1, mul);        // X*con0 + con0*con1
 130           add2->set_req(2, phase->makecon(tcon01) );
 131           progress = add2;
 132         }
 133       }
 134     } // End of is left input an add
 135   } // End of is right input a Mul
 136 
 137   return progress;
 138 }
 139 
 140 //------------------------------Value-----------------------------------------
 141 const Type *MulNode::Value( PhaseTransform *phase ) const {
 142   const Type *t1 = phase->type( in(1) );
 143   const Type *t2 = phase->type( in(2) );
 144   // Either input is TOP ==> the result is TOP
 145   if( t1 == Type::TOP ) return Type::TOP;
 146   if( t2 == Type::TOP ) return Type::TOP;
 147 
 148   // Either input is ZERO ==> the result is ZERO.
 149   // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0
 150   int op = Opcode();
 151   if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) {
 152     const Type *zero = add_id();        // The multiplicative zero
 153     if( t1->higher_equal( zero ) ) return zero;
 154     if( t2->higher_equal( zero ) ) return zero;
 155   }
 156 
 157   // Either input is BOTTOM ==> the result is the local BOTTOM
 158   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
 159     return bottom_type();
 160 
 161 #if defined(IA32)
 162   // Can't trust native compilers to properly fold strict double
 163   // multiplication with round-to-zero on this platform.
 164   if (op == Op_MulD && phase->C->method()->is_strict()) {
 165     return TypeD::DOUBLE;
 166   }
 167 #endif
 168 
 169   return mul_ring(t1,t2);            // Local flavor of type multiplication
 170 }
 171 
 172 
 173 //=============================================================================
 174 //------------------------------Ideal------------------------------------------
 175 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
 176 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 177   // Swap constant to right
 178   jint con;
 179   if ((con = in(1)->find_int_con(0)) != 0) {
 180     swap_edges(1, 2);
 181     // Finish rest of method to use info in 'con'
 182   } else if ((con = in(2)->find_int_con(0)) == 0) {
 183     return MulNode::Ideal(phase, can_reshape);
 184   }
 185 
 186   // Now we have a constant Node on the right and the constant in con
 187   if( con == 0 ) return NULL;   // By zero is handled by Value call
 188   if( con == 1 ) return NULL;   // By one  is handled by Identity call
 189 
 190   // Check for negative constant; if so negate the final result
 191   bool sign_flip = false;
 192   if( con < 0 ) {
 193     con = -con;
 194     sign_flip = true;
 195   }
 196 
 197   // Get low bit; check for being the only bit
 198   Node *res = NULL;
 199   jint bit1 = con & -con;       // Extract low bit
 200   if( bit1 == con ) {           // Found a power of 2?
 201     res = new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) );
 202   } else {
 203 
 204     // Check for constant with 2 bits set
 205     jint bit2 = con-bit1;
 206     bit2 = bit2 & -bit2;          // Extract 2nd bit
 207     if( bit2 + bit1 == con ) {    // Found all bits in con?
 208       Node *n1 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) );
 209       Node *n2 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) );
 210       res = new (phase->C) AddINode( n2, n1 );
 211 
 212     } else if (is_power_of_2(con+1)) {
 213       // Sleezy: power-of-2 -1.  Next time be generic.
 214       jint temp = (jint) (con + 1);
 215       Node *n1 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) );
 216       res = new (phase->C) SubINode( n1, in(1) );
 217     } else {
 218       return MulNode::Ideal(phase, can_reshape);
 219     }
 220   }
 221 
 222   if( sign_flip ) {             // Need to negate result?
 223     res = phase->transform(res);// Transform, before making the zero con
 224     res = new (phase->C) SubINode(phase->intcon(0),res);
 225   }
 226 
 227   return res;                   // Return final result
 228 }
 229 
 230 //------------------------------mul_ring---------------------------------------
 231 // Compute the product type of two integer ranges into this node.
 232 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const {
 233   const TypeInt *r0 = t0->is_int(); // Handy access
 234   const TypeInt *r1 = t1->is_int();
 235 
 236   // Fetch endpoints of all ranges
 237   int32 lo0 = r0->_lo;
 238   double a = (double)lo0;
 239   int32 hi0 = r0->_hi;
 240   double b = (double)hi0;
 241   int32 lo1 = r1->_lo;
 242   double c = (double)lo1;
 243   int32 hi1 = r1->_hi;
 244   double d = (double)hi1;
 245 
 246   // Compute all endpoints & check for overflow
 247   int32 A = lo0*lo1;
 248   if( (double)A != a*c ) return TypeInt::INT; // Overflow?
 249   int32 B = lo0*hi1;
 250   if( (double)B != a*d ) return TypeInt::INT; // Overflow?
 251   int32 C = hi0*lo1;
 252   if( (double)C != b*c ) return TypeInt::INT; // Overflow?
 253   int32 D = hi0*hi1;
 254   if( (double)D != b*d ) return TypeInt::INT; // Overflow?
 255 
 256   if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
 257   else { lo0 = B; hi0 = A; }
 258   if( C < D ) {
 259     if( C < lo0 ) lo0 = C;
 260     if( D > hi0 ) hi0 = D;
 261   } else {
 262     if( D < lo0 ) lo0 = D;
 263     if( C > hi0 ) hi0 = C;
 264   }
 265   return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
 266 }
 267 
 268 
 269 //=============================================================================
 270 //------------------------------Ideal------------------------------------------
 271 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
 272 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 273   // Swap constant to right
 274   jlong con;
 275   if ((con = in(1)->find_long_con(0)) != 0) {
 276     swap_edges(1, 2);
 277     // Finish rest of method to use info in 'con'
 278   } else if ((con = in(2)->find_long_con(0)) == 0) {
 279     return MulNode::Ideal(phase, can_reshape);
 280   }
 281 
 282   // Now we have a constant Node on the right and the constant in con
 283   if( con == CONST64(0) ) return NULL;  // By zero is handled by Value call
 284   if( con == CONST64(1) ) return NULL;  // By one  is handled by Identity call
 285 
 286   // Check for negative constant; if so negate the final result
 287   bool sign_flip = false;
 288   if( con < 0 ) {
 289     con = -con;
 290     sign_flip = true;
 291   }
 292 
 293   // Get low bit; check for being the only bit
 294   Node *res = NULL;
 295   jlong bit1 = con & -con;      // Extract low bit
 296   if( bit1 == con ) {           // Found a power of 2?
 297     res = new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) );
 298   } else {
 299 
 300     // Check for constant with 2 bits set
 301     jlong bit2 = con-bit1;
 302     bit2 = bit2 & -bit2;          // Extract 2nd bit
 303     if( bit2 + bit1 == con ) {    // Found all bits in con?
 304       Node *n1 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) );
 305       Node *n2 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) );
 306       res = new (phase->C) AddLNode( n2, n1 );
 307 
 308     } else if (is_power_of_2_long(con+1)) {
 309       // Sleezy: power-of-2 -1.  Next time be generic.
 310       jlong temp = (jlong) (con + 1);
 311       Node *n1 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) );
 312       res = new (phase->C) SubLNode( n1, in(1) );
 313     } else {
 314       return MulNode::Ideal(phase, can_reshape);
 315     }
 316   }
 317 
 318   if( sign_flip ) {             // Need to negate result?
 319     res = phase->transform(res);// Transform, before making the zero con
 320     res = new (phase->C) SubLNode(phase->longcon(0),res);
 321   }
 322 
 323   return res;                   // Return final result
 324 }
 325 
 326 //------------------------------mul_ring---------------------------------------
 327 // Compute the product type of two integer ranges into this node.
 328 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const {
 329   const TypeLong *r0 = t0->is_long(); // Handy access
 330   const TypeLong *r1 = t1->is_long();
 331 
 332   // Fetch endpoints of all ranges
 333   jlong lo0 = r0->_lo;
 334   double a = (double)lo0;
 335   jlong hi0 = r0->_hi;
 336   double b = (double)hi0;
 337   jlong lo1 = r1->_lo;
 338   double c = (double)lo1;
 339   jlong hi1 = r1->_hi;
 340   double d = (double)hi1;
 341 
 342   // Compute all endpoints & check for overflow
 343   jlong A = lo0*lo1;
 344   if( (double)A != a*c ) return TypeLong::LONG; // Overflow?
 345   jlong B = lo0*hi1;
 346   if( (double)B != a*d ) return TypeLong::LONG; // Overflow?
 347   jlong C = hi0*lo1;
 348   if( (double)C != b*c ) return TypeLong::LONG; // Overflow?
 349   jlong D = hi0*hi1;
 350   if( (double)D != b*d ) return TypeLong::LONG; // Overflow?
 351 
 352   if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
 353   else { lo0 = B; hi0 = A; }
 354   if( C < D ) {
 355     if( C < lo0 ) lo0 = C;
 356     if( D > hi0 ) hi0 = D;
 357   } else {
 358     if( D < lo0 ) lo0 = D;
 359     if( C > hi0 ) hi0 = C;
 360   }
 361   return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
 362 }
 363 
 364 //=============================================================================
 365 //------------------------------mul_ring---------------------------------------
 366 // Compute the product type of two double ranges into this node.
 367 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const {
 368   if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT;
 369   return TypeF::make( t0->getf() * t1->getf() );
 370 }
 371 
 372 //=============================================================================
 373 //------------------------------mul_ring---------------------------------------
 374 // Compute the product type of two double ranges into this node.
 375 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const {
 376   if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE;
 377   // We must be multiplying 2 double constants.
 378   return TypeD::make( t0->getd() * t1->getd() );
 379 }
 380 
 381 //=============================================================================
 382 //------------------------------Value------------------------------------------
 383 const Type *MulHiLNode::Value( PhaseTransform *phase ) const {
 384   // Either input is TOP ==> the result is TOP
 385   const Type *t1 = phase->type( in(1) );
 386   const Type *t2 = phase->type( in(2) );
 387   if( t1 == Type::TOP ) return Type::TOP;
 388   if( t2 == Type::TOP ) return Type::TOP;
 389 
 390   // Either input is BOTTOM ==> the result is the local BOTTOM
 391   const Type *bot = bottom_type();
 392   if( (t1 == bot) || (t2 == bot) ||
 393       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 394     return bot;
 395 
 396   // It is not worth trying to constant fold this stuff!
 397   return TypeLong::LONG;
 398 }
 399 
 400 //=============================================================================
 401 //------------------------------mul_ring---------------------------------------
 402 // Supplied function returns the product of the inputs IN THE CURRENT RING.
 403 // For the logical operations the ring's MUL is really a logical AND function.
 404 // This also type-checks the inputs for sanity.  Guaranteed never to
 405 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 406 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const {
 407   const TypeInt *r0 = t0->is_int(); // Handy access
 408   const TypeInt *r1 = t1->is_int();
 409   int widen = MAX2(r0->_widen,r1->_widen);
 410 
 411   // If either input is a constant, might be able to trim cases
 412   if( !r0->is_con() && !r1->is_con() )
 413     return TypeInt::INT;        // No constants to be had
 414 
 415   // Both constants?  Return bits
 416   if( r0->is_con() && r1->is_con() )
 417     return TypeInt::make( r0->get_con() & r1->get_con() );
 418 
 419   if( r0->is_con() && r0->get_con() > 0 )
 420     return TypeInt::make(0, r0->get_con(), widen);
 421 
 422   if( r1->is_con() && r1->get_con() > 0 )
 423     return TypeInt::make(0, r1->get_con(), widen);
 424 
 425   if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) {
 426     return TypeInt::BOOL;
 427   }
 428 
 429   return TypeInt::INT;          // No constants to be had
 430 }
 431 
 432 //------------------------------Identity---------------------------------------
 433 // Masking off the high bits of an unsigned load is not required
 434 Node *AndINode::Identity( PhaseTransform *phase ) {
 435 
 436   // x & x => x
 437   if (phase->eqv(in(1), in(2))) return in(1);
 438 
 439   Node* in1 = in(1);
 440   uint op = in1->Opcode();
 441   const TypeInt* t2 = phase->type(in(2))->isa_int();
 442   if (t2 && t2->is_con()) {
 443     int con = t2->get_con();
 444     // Masking off high bits which are always zero is useless.
 445     const TypeInt* t1 = phase->type( in(1) )->isa_int();
 446     if (t1 != NULL && t1->_lo >= 0) {
 447       jint t1_support = right_n_bits(1 + log2_intptr(t1->_hi));
 448       if ((t1_support & con) == t1_support)
 449         return in1;
 450     }
 451     // Masking off the high bits of a unsigned-shift-right is not
 452     // needed either.
 453     if (op == Op_URShiftI) {
 454       const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
 455       if (t12 && t12->is_con()) {  // Shift is by a constant
 456         int shift = t12->get_con();
 457         shift &= BitsPerJavaInteger - 1;  // semantics of Java shifts
 458         int mask = max_juint >> shift;
 459         if ((mask & con) == mask)  // If AND is useless, skip it
 460           return in1;
 461       }
 462     }
 463   }
 464   return MulNode::Identity(phase);
 465 }
 466 
 467 //------------------------------Ideal------------------------------------------
 468 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 469   // Special case constant AND mask
 470   const TypeInt *t2 = phase->type( in(2) )->isa_int();
 471   if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
 472   const int mask = t2->get_con();
 473   Node *load = in(1);
 474   uint lop = load->Opcode();
 475 
 476   // Masking bits off of a Character?  Hi bits are already zero.
 477   if( lop == Op_LoadUS &&
 478       (mask & 0xFFFF0000) )     // Can we make a smaller mask?
 479     return new (phase->C) AndINode(load,phase->intcon(mask&0xFFFF));
 480 
 481   // Masking bits off of a Short?  Loading a Character does some masking
 482   if (can_reshape &&
 483       load->outcnt() == 1 && load->unique_out() == this) {
 484     if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) {
 485       Node *ldus = new (phase->C) LoadUSNode(load->in(MemNode::Control),
 486                                              load->in(MemNode::Memory),
 487                                              load->in(MemNode::Address),
 488                                              load->adr_type(),
 489                                              TypeInt::CHAR, LoadNode::unordered);
 490       ldus = phase->transform(ldus);
 491       return new (phase->C) AndINode(ldus, phase->intcon(mask & 0xFFFF));
 492     }
 493 
 494     // Masking sign bits off of a Byte?  Do an unsigned byte load plus
 495     // an and.
 496     if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
 497       Node* ldub = new (phase->C) LoadUBNode(load->in(MemNode::Control),
 498                                              load->in(MemNode::Memory),
 499                                              load->in(MemNode::Address),
 500                                              load->adr_type(),
 501                                              TypeInt::UBYTE, LoadNode::unordered);
 502       ldub = phase->transform(ldub);
 503       return new (phase->C) AndINode(ldub, phase->intcon(mask));
 504     }
 505   }
 506 
 507   // Masking off sign bits?  Dont make them!
 508   if( lop == Op_RShiftI ) {
 509     const TypeInt *t12 = phase->type(load->in(2))->isa_int();
 510     if( t12 && t12->is_con() ) { // Shift is by a constant
 511       int shift = t12->get_con();
 512       shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
 513       const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift);
 514       // If the AND'ing of the 2 masks has no bits, then only original shifted
 515       // bits survive.  NO sign-extension bits survive the maskings.
 516       if( (sign_bits_mask & mask) == 0 ) {
 517         // Use zero-fill shift instead
 518         Node *zshift = phase->transform(new (phase->C) URShiftINode(load->in(1),load->in(2)));
 519         return new (phase->C) AndINode( zshift, in(2) );
 520       }
 521     }
 522   }
 523 
 524   // Check for 'negate/and-1', a pattern emitted when someone asks for
 525   // 'mod 2'.  Negate leaves the low order bit unchanged (think: complement
 526   // plus 1) and the mask is of the low order bit.  Skip the negate.
 527   if( lop == Op_SubI && mask == 1 && load->in(1) &&
 528       phase->type(load->in(1)) == TypeInt::ZERO )
 529     return new (phase->C) AndINode( load->in(2), in(2) );
 530 
 531   return MulNode::Ideal(phase, can_reshape);
 532 }
 533 
 534 //=============================================================================
 535 //------------------------------mul_ring---------------------------------------
 536 // Supplied function returns the product of the inputs IN THE CURRENT RING.
 537 // For the logical operations the ring's MUL is really a logical AND function.
 538 // This also type-checks the inputs for sanity.  Guaranteed never to
 539 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 540 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const {
 541   const TypeLong *r0 = t0->is_long(); // Handy access
 542   const TypeLong *r1 = t1->is_long();
 543   int widen = MAX2(r0->_widen,r1->_widen);
 544 
 545   // If either input is a constant, might be able to trim cases
 546   if( !r0->is_con() && !r1->is_con() )
 547     return TypeLong::LONG;      // No constants to be had
 548 
 549   // Both constants?  Return bits
 550   if( r0->is_con() && r1->is_con() )
 551     return TypeLong::make( r0->get_con() & r1->get_con() );
 552 
 553   if( r0->is_con() && r0->get_con() > 0 )
 554     return TypeLong::make(CONST64(0), r0->get_con(), widen);
 555 
 556   if( r1->is_con() && r1->get_con() > 0 )
 557     return TypeLong::make(CONST64(0), r1->get_con(), widen);
 558 
 559   return TypeLong::LONG;        // No constants to be had
 560 }
 561 
 562 //------------------------------Identity---------------------------------------
 563 // Masking off the high bits of an unsigned load is not required
 564 Node *AndLNode::Identity( PhaseTransform *phase ) {
 565 
 566   // x & x => x
 567   if (phase->eqv(in(1), in(2))) return in(1);
 568 
 569   Node *usr = in(1);
 570   const TypeLong *t2 = phase->type( in(2) )->isa_long();
 571   if( t2 && t2->is_con() ) {
 572     jlong con = t2->get_con();
 573     // Masking off high bits which are always zero is useless.
 574     const TypeLong* t1 = phase->type( in(1) )->isa_long();
 575     if (t1 != NULL && t1->_lo >= 0) {
 576       jlong t1_support = ((jlong)1 << (1 + log2_long(t1->_hi))) - 1;
 577       if ((t1_support & con) == t1_support)
 578         return usr;
 579     }
 580     uint lop = usr->Opcode();
 581     // Masking off the high bits of a unsigned-shift-right is not
 582     // needed either.
 583     if( lop == Op_URShiftL ) {
 584       const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
 585       if( t12 && t12->is_con() ) {  // Shift is by a constant
 586         int shift = t12->get_con();
 587         shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
 588         jlong mask = max_julong >> shift;
 589         if( (mask&con) == mask )  // If AND is useless, skip it
 590           return usr;
 591       }
 592     }
 593   }
 594   return MulNode::Identity(phase);
 595 }
 596 
 597 //------------------------------Ideal------------------------------------------
 598 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 599   // Special case constant AND mask
 600   const TypeLong *t2 = phase->type( in(2) )->isa_long();
 601   if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
 602   const jlong mask = t2->get_con();
 603 
 604   Node* in1 = in(1);
 605   uint op = in1->Opcode();
 606 
 607   // Are we masking a long that was converted from an int with a mask
 608   // that fits in 32-bits?  Commute them and use an AndINode.  Don't
 609   // convert masks which would cause a sign extension of the integer
 610   // value.  This check includes UI2L masks (0x00000000FFFFFFFF) which
 611   // would be optimized away later in Identity.
 612   if (op == Op_ConvI2L && (mask & CONST64(0xFFFFFFFF80000000)) == 0) {
 613     Node* andi = new (phase->C) AndINode(in1->in(1), phase->intcon(mask));
 614     andi = phase->transform(andi);
 615     return new (phase->C) ConvI2LNode(andi);
 616   }
 617 
 618   // Masking off sign bits?  Dont make them!
 619   if (op == Op_RShiftL) {
 620     const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
 621     if( t12 && t12->is_con() ) { // Shift is by a constant
 622       int shift = t12->get_con();
 623       shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
 624       const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
 625       // If the AND'ing of the 2 masks has no bits, then only original shifted
 626       // bits survive.  NO sign-extension bits survive the maskings.
 627       if( (sign_bits_mask & mask) == 0 ) {
 628         // Use zero-fill shift instead
 629         Node *zshift = phase->transform(new (phase->C) URShiftLNode(in1->in(1), in1->in(2)));
 630         return new (phase->C) AndLNode(zshift, in(2));
 631       }
 632     }
 633   }
 634 
 635   return MulNode::Ideal(phase, can_reshape);
 636 }
 637 
 638 //=============================================================================
 639 //------------------------------Identity---------------------------------------
 640 Node *LShiftINode::Identity( PhaseTransform *phase ) {
 641   const TypeInt *ti = phase->type( in(2) )->isa_int();  // shift count is an int
 642   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this;
 643 }
 644 
 645 //------------------------------Ideal------------------------------------------
 646 // If the right input is a constant, and the left input is an add of a
 647 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
 648 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 649   const Type *t  = phase->type( in(2) );
 650   if( t == Type::TOP ) return NULL;       // Right input is dead
 651   const TypeInt *t2 = t->isa_int();
 652   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
 653   const int con = t2->get_con() & ( BitsPerInt - 1 );  // masked shift count
 654 
 655   if ( con == 0 )  return NULL; // let Identity() handle 0 shift count
 656 
 657   // Left input is an add of a constant?
 658   Node *add1 = in(1);
 659   int add1_op = add1->Opcode();
 660   if( add1_op == Op_AddI ) {    // Left input is an add?
 661     assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" );
 662     const TypeInt *t12 = phase->type(add1->in(2))->isa_int();
 663     if( t12 && t12->is_con() ){ // Left input is an add of a con?
 664       // Transform is legal, but check for profit.  Avoid breaking 'i2s'
 665       // and 'i2b' patterns which typically fold into 'StoreC/StoreB'.
 666       if( con < 16 ) {
 667         // Compute X << con0
 668         Node *lsh = phase->transform( new (phase->C) LShiftINode( add1->in(1), in(2) ) );
 669         // Compute X<<con0 + (con1<<con0)
 670         return new (phase->C) AddINode( lsh, phase->intcon(t12->get_con() << con));
 671       }
 672     }
 673   }
 674 
 675   // Check for "(x>>c0)<<c0" which just masks off low bits
 676   if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) &&
 677       add1->in(2) == in(2) )
 678     // Convert to "(x & -(1<<c0))"
 679     return new (phase->C) AndINode(add1->in(1),phase->intcon( -(1<<con)));
 680 
 681   // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
 682   if( add1_op == Op_AndI ) {
 683     Node *add2 = add1->in(1);
 684     int add2_op = add2->Opcode();
 685     if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) &&
 686         add2->in(2) == in(2) ) {
 687       // Convert to "(x & (Y<<c0))"
 688       Node *y_sh = phase->transform( new (phase->C) LShiftINode( add1->in(2), in(2) ) );
 689       return new (phase->C) AndINode( add2->in(1), y_sh );
 690     }
 691   }
 692 
 693   // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits
 694   // before shifting them away.
 695   const jint bits_mask = right_n_bits(BitsPerJavaInteger-con);
 696   if( add1_op == Op_AndI &&
 697       phase->type(add1->in(2)) == TypeInt::make( bits_mask ) )
 698     return new (phase->C) LShiftINode( add1->in(1), in(2) );
 699 
 700   return NULL;
 701 }
 702 
 703 //------------------------------Value------------------------------------------
 704 // A LShiftINode shifts its input2 left by input1 amount.
 705 const Type *LShiftINode::Value( PhaseTransform *phase ) const {
 706   const Type *t1 = phase->type( in(1) );
 707   const Type *t2 = phase->type( in(2) );
 708   // Either input is TOP ==> the result is TOP
 709   if( t1 == Type::TOP ) return Type::TOP;
 710   if( t2 == Type::TOP ) return Type::TOP;
 711 
 712   // Left input is ZERO ==> the result is ZERO.
 713   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
 714   // Shift by zero does nothing
 715   if( t2 == TypeInt::ZERO ) return t1;
 716 
 717   // Either input is BOTTOM ==> the result is BOTTOM
 718   if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) ||
 719       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 720     return TypeInt::INT;
 721 
 722   const TypeInt *r1 = t1->is_int(); // Handy access
 723   const TypeInt *r2 = t2->is_int(); // Handy access
 724 
 725   if (!r2->is_con())
 726     return TypeInt::INT;
 727 
 728   uint shift = r2->get_con();
 729   shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
 730   // Shift by a multiple of 32 does nothing:
 731   if (shift == 0)  return t1;
 732 
 733   // If the shift is a constant, shift the bounds of the type,
 734   // unless this could lead to an overflow.
 735   if (!r1->is_con()) {
 736     jint lo = r1->_lo, hi = r1->_hi;
 737     if (((lo << shift) >> shift) == lo &&
 738         ((hi << shift) >> shift) == hi) {
 739       // No overflow.  The range shifts up cleanly.
 740       return TypeInt::make((jint)lo << (jint)shift,
 741                            (jint)hi << (jint)shift,
 742                            MAX2(r1->_widen,r2->_widen));
 743     }
 744     return TypeInt::INT;
 745   }
 746 
 747   return TypeInt::make( (jint)r1->get_con() << (jint)shift );
 748 }
 749 
 750 //=============================================================================
 751 //------------------------------Identity---------------------------------------
 752 Node *LShiftLNode::Identity( PhaseTransform *phase ) {
 753   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
 754   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
 755 }
 756 
 757 //------------------------------Ideal------------------------------------------
 758 // If the right input is a constant, and the left input is an add of a
 759 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
 760 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 761   const Type *t  = phase->type( in(2) );
 762   if( t == Type::TOP ) return NULL;       // Right input is dead
 763   const TypeInt *t2 = t->isa_int();
 764   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
 765   const int con = t2->get_con() & ( BitsPerLong - 1 );  // masked shift count
 766 
 767   if ( con == 0 ) return NULL;  // let Identity() handle 0 shift count
 768 
 769   // Left input is an add of a constant?
 770   Node *add1 = in(1);
 771   int add1_op = add1->Opcode();
 772   if( add1_op == Op_AddL ) {    // Left input is an add?
 773     // Avoid dead data cycles from dead loops
 774     assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" );
 775     const TypeLong *t12 = phase->type(add1->in(2))->isa_long();
 776     if( t12 && t12->is_con() ){ // Left input is an add of a con?
 777       // Compute X << con0
 778       Node *lsh = phase->transform( new (phase->C) LShiftLNode( add1->in(1), in(2) ) );
 779       // Compute X<<con0 + (con1<<con0)
 780       return new (phase->C) AddLNode( lsh, phase->longcon(t12->get_con() << con));
 781     }
 782   }
 783 
 784   // Check for "(x>>c0)<<c0" which just masks off low bits
 785   if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) &&
 786       add1->in(2) == in(2) )
 787     // Convert to "(x & -(1<<c0))"
 788     return new (phase->C) AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con)));
 789 
 790   // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
 791   if( add1_op == Op_AndL ) {
 792     Node *add2 = add1->in(1);
 793     int add2_op = add2->Opcode();
 794     if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) &&
 795         add2->in(2) == in(2) ) {
 796       // Convert to "(x & (Y<<c0))"
 797       Node *y_sh = phase->transform( new (phase->C) LShiftLNode( add1->in(2), in(2) ) );
 798       return new (phase->C) AndLNode( add2->in(1), y_sh );
 799     }
 800   }
 801 
 802   // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
 803   // before shifting them away.
 804   const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) - CONST64(1);
 805   if( add1_op == Op_AndL &&
 806       phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
 807     return new (phase->C) LShiftLNode( add1->in(1), in(2) );
 808 
 809   return NULL;
 810 }
 811 
 812 //------------------------------Value------------------------------------------
 813 // A LShiftLNode shifts its input2 left by input1 amount.
 814 const Type *LShiftLNode::Value( PhaseTransform *phase ) const {
 815   const Type *t1 = phase->type( in(1) );
 816   const Type *t2 = phase->type( in(2) );
 817   // Either input is TOP ==> the result is TOP
 818   if( t1 == Type::TOP ) return Type::TOP;
 819   if( t2 == Type::TOP ) return Type::TOP;
 820 
 821   // Left input is ZERO ==> the result is ZERO.
 822   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
 823   // Shift by zero does nothing
 824   if( t2 == TypeInt::ZERO ) return t1;
 825 
 826   // Either input is BOTTOM ==> the result is BOTTOM
 827   if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) ||
 828       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
 829     return TypeLong::LONG;
 830 
 831   const TypeLong *r1 = t1->is_long(); // Handy access
 832   const TypeInt  *r2 = t2->is_int();  // Handy access
 833 
 834   if (!r2->is_con())
 835     return TypeLong::LONG;
 836 
 837   uint shift = r2->get_con();
 838   shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
 839   // Shift by a multiple of 64 does nothing:
 840   if (shift == 0)  return t1;
 841 
 842   // If the shift is a constant, shift the bounds of the type,
 843   // unless this could lead to an overflow.
 844   if (!r1->is_con()) {
 845     jlong lo = r1->_lo, hi = r1->_hi;
 846     if (((lo << shift) >> shift) == lo &&
 847         ((hi << shift) >> shift) == hi) {
 848       // No overflow.  The range shifts up cleanly.
 849       return TypeLong::make((jlong)lo << (jint)shift,
 850                             (jlong)hi << (jint)shift,
 851                             MAX2(r1->_widen,r2->_widen));
 852     }
 853     return TypeLong::LONG;
 854   }
 855 
 856   return TypeLong::make( (jlong)r1->get_con() << (jint)shift );
 857 }
 858 
 859 //=============================================================================
 860 //------------------------------Identity---------------------------------------
 861 Node *RShiftINode::Identity( PhaseTransform *phase ) {
 862   const TypeInt *t2 = phase->type(in(2))->isa_int();
 863   if( !t2 ) return this;
 864   if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 )
 865     return in(1);
 866 
 867   // Check for useless sign-masking
 868   if( in(1)->Opcode() == Op_LShiftI &&
 869       in(1)->req() == 3 &&
 870       in(1)->in(2) == in(2) &&
 871       t2->is_con() ) {
 872     uint shift = t2->get_con();
 873     shift &= BitsPerJavaInteger-1; // semantics of Java shifts
 874     // Compute masks for which this shifting doesn't change
 875     int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000
 876     int hi = ~lo;               // 00007FFF
 877     const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int();
 878     if( !t11 ) return this;
 879     // Does actual value fit inside of mask?
 880     if( lo <= t11->_lo && t11->_hi <= hi )
 881       return in(1)->in(1);      // Then shifting is a nop
 882   }
 883 
 884   return this;
 885 }
 886 
 887 //------------------------------Ideal------------------------------------------
 888 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
 889   // Inputs may be TOP if they are dead.
 890   const TypeInt *t1 = phase->type( in(1) )->isa_int();
 891   if( !t1 ) return NULL;        // Left input is an integer
 892   const TypeInt *t2 = phase->type( in(2) )->isa_int();
 893   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
 894   const TypeInt *t3;  // type of in(1).in(2)
 895   int shift = t2->get_con();
 896   shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
 897 
 898   if ( shift == 0 ) return NULL;  // let Identity() handle 0 shift count
 899 
 900   // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller.
 901   // Such expressions arise normally from shift chains like (byte)(x >> 24).
 902   const Node *mask = in(1);
 903   if( mask->Opcode() == Op_AndI &&
 904       (t3 = phase->type(mask->in(2))->isa_int()) &&
 905       t3->is_con() ) {
 906     Node *x = mask->in(1);
 907     jint maskbits = t3->get_con();
 908     // Convert to "(x >> shift) & (mask >> shift)"
 909     Node *shr_nomask = phase->transform( new (phase->C) RShiftINode(mask->in(1), in(2)) );
 910     return new (phase->C) AndINode(shr_nomask, phase->intcon( maskbits >> shift));
 911   }
 912 
 913   // Check for "(short[i] <<16)>>16" which simply sign-extends
 914   const Node *shl = in(1);
 915   if( shl->Opcode() != Op_LShiftI ) return NULL;
 916 
 917   if( shift == 16 &&
 918       (t3 = phase->type(shl->in(2))->isa_int()) &&
 919       t3->is_con(16) ) {
 920     Node *ld = shl->in(1);
 921     if( ld->Opcode() == Op_LoadS ) {
 922       // Sign extension is just useless here.  Return a RShiftI of zero instead
 923       // returning 'ld' directly.  We cannot return an old Node directly as
 924       // that is the job of 'Identity' calls and Identity calls only work on
 925       // direct inputs ('ld' is an extra Node removed from 'this').  The
 926       // combined optimization requires Identity only return direct inputs.
 927       set_req(1, ld);
 928       set_req(2, phase->intcon(0));
 929       return this;
 930     }
 931     else if( can_reshape &&
 932              ld->Opcode() == Op_LoadUS &&
 933              ld->outcnt() == 1 && ld->unique_out() == shl)
 934       // Replace zero-extension-load with sign-extension-load
 935       return new (phase->C) LoadSNode( ld->in(MemNode::Control),
 936                                        ld->in(MemNode::Memory),
 937                                        ld->in(MemNode::Address),
 938                                        ld->adr_type(), TypeInt::SHORT,
 939                                        LoadNode::unordered);
 940   }
 941 
 942   // Check for "(byte[i] <<24)>>24" which simply sign-extends
 943   if( shift == 24 &&
 944       (t3 = phase->type(shl->in(2))->isa_int()) &&
 945       t3->is_con(24) ) {
 946     Node *ld = shl->in(1);
 947     if( ld->Opcode() == Op_LoadB ) {
 948       // Sign extension is just useless here
 949       set_req(1, ld);
 950       set_req(2, phase->intcon(0));
 951       return this;
 952     }
 953   }
 954 
 955   return NULL;
 956 }
 957 
 958 //------------------------------Value------------------------------------------
 959 // A RShiftINode shifts its input2 right by input1 amount.
 960 const Type *RShiftINode::Value( PhaseTransform *phase ) const {
 961   const Type *t1 = phase->type( in(1) );
 962   const Type *t2 = phase->type( in(2) );
 963   // Either input is TOP ==> the result is TOP
 964   if( t1 == Type::TOP ) return Type::TOP;
 965   if( t2 == Type::TOP ) return Type::TOP;
 966 
 967   // Left input is ZERO ==> the result is ZERO.
 968   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
 969   // Shift by zero does nothing
 970   if( t2 == TypeInt::ZERO ) return t1;
 971 
 972   // Either input is BOTTOM ==> the result is BOTTOM
 973   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
 974     return TypeInt::INT;
 975 
 976   if (t2 == TypeInt::INT)
 977     return TypeInt::INT;
 978 
 979   const TypeInt *r1 = t1->is_int(); // Handy access
 980   const TypeInt *r2 = t2->is_int(); // Handy access
 981 
 982   // If the shift is a constant, just shift the bounds of the type.
 983   // For example, if the shift is 31, we just propagate sign bits.
 984   if (r2->is_con()) {
 985     uint shift = r2->get_con();
 986     shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
 987     // Shift by a multiple of 32 does nothing:
 988     if (shift == 0)  return t1;
 989     // Calculate reasonably aggressive bounds for the result.
 990     // This is necessary if we are to correctly type things
 991     // like (x<<24>>24) == ((byte)x).
 992     jint lo = (jint)r1->_lo >> (jint)shift;
 993     jint hi = (jint)r1->_hi >> (jint)shift;
 994     assert(lo <= hi, "must have valid bounds");
 995     const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
 996 #ifdef ASSERT
 997     // Make sure we get the sign-capture idiom correct.
 998     if (shift == BitsPerJavaInteger-1) {
 999       if (r1->_lo >= 0) assert(ti == TypeInt::ZERO,    ">>31 of + is  0");
1000       if (r1->_hi <  0) assert(ti == TypeInt::MINUS_1, ">>31 of - is -1");
1001     }
1002 #endif
1003     return ti;
1004   }
1005 
1006   if( !r1->is_con() || !r2->is_con() )
1007     return TypeInt::INT;
1008 
1009   // Signed shift right
1010   return TypeInt::make( r1->get_con() >> (r2->get_con()&31) );
1011 }
1012 
1013 //=============================================================================
1014 //------------------------------Identity---------------------------------------
1015 Node *RShiftLNode::Identity( PhaseTransform *phase ) {
1016   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
1017   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
1018 }
1019 
1020 //------------------------------Value------------------------------------------
1021 // A RShiftLNode shifts its input2 right by input1 amount.
1022 const Type *RShiftLNode::Value( PhaseTransform *phase ) const {
1023   const Type *t1 = phase->type( in(1) );
1024   const Type *t2 = phase->type( in(2) );
1025   // Either input is TOP ==> the result is TOP
1026   if( t1 == Type::TOP ) return Type::TOP;
1027   if( t2 == Type::TOP ) return Type::TOP;
1028 
1029   // Left input is ZERO ==> the result is ZERO.
1030   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
1031   // Shift by zero does nothing
1032   if( t2 == TypeInt::ZERO ) return t1;
1033 
1034   // Either input is BOTTOM ==> the result is BOTTOM
1035   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1036     return TypeLong::LONG;
1037 
1038   if (t2 == TypeInt::INT)
1039     return TypeLong::LONG;
1040 
1041   const TypeLong *r1 = t1->is_long(); // Handy access
1042   const TypeInt  *r2 = t2->is_int (); // Handy access
1043 
1044   // If the shift is a constant, just shift the bounds of the type.
1045   // For example, if the shift is 63, we just propagate sign bits.
1046   if (r2->is_con()) {
1047     uint shift = r2->get_con();
1048     shift &= (2*BitsPerJavaInteger)-1;  // semantics of Java shifts
1049     // Shift by a multiple of 64 does nothing:
1050     if (shift == 0)  return t1;
1051     // Calculate reasonably aggressive bounds for the result.
1052     // This is necessary if we are to correctly type things
1053     // like (x<<24>>24) == ((byte)x).
1054     jlong lo = (jlong)r1->_lo >> (jlong)shift;
1055     jlong hi = (jlong)r1->_hi >> (jlong)shift;
1056     assert(lo <= hi, "must have valid bounds");
1057     const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1058     #ifdef ASSERT
1059     // Make sure we get the sign-capture idiom correct.
1060     if (shift == (2*BitsPerJavaInteger)-1) {
1061       if (r1->_lo >= 0) assert(tl == TypeLong::ZERO,    ">>63 of + is 0");
1062       if (r1->_hi < 0)  assert(tl == TypeLong::MINUS_1, ">>63 of - is -1");
1063     }
1064     #endif
1065     return tl;
1066   }
1067 
1068   return TypeLong::LONG;                // Give up
1069 }
1070 
1071 //=============================================================================
1072 //------------------------------Identity---------------------------------------
1073 Node *URShiftINode::Identity( PhaseTransform *phase ) {
1074   const TypeInt *ti = phase->type( in(2) )->isa_int();
1075   if ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) return in(1);
1076 
1077   // Check for "((x << LogBytesPerWord) + (wordSize-1)) >> LogBytesPerWord" which is just "x".
1078   // Happens during new-array length computation.
1079   // Safe if 'x' is in the range [0..(max_int>>LogBytesPerWord)]
1080   Node *add = in(1);
1081   if( add->Opcode() == Op_AddI ) {
1082     const TypeInt *t2  = phase->type(add->in(2))->isa_int();
1083     if( t2 && t2->is_con(wordSize - 1) &&
1084         add->in(1)->Opcode() == Op_LShiftI ) {
1085       // Check that shift_counts are LogBytesPerWord
1086       Node          *lshift_count   = add->in(1)->in(2);
1087       const TypeInt *t_lshift_count = phase->type(lshift_count)->isa_int();
1088       if( t_lshift_count && t_lshift_count->is_con(LogBytesPerWord) &&
1089           t_lshift_count == phase->type(in(2)) ) {
1090         Node          *x   = add->in(1)->in(1);
1091         const TypeInt *t_x = phase->type(x)->isa_int();
1092         if( t_x != NULL && 0 <= t_x->_lo && t_x->_hi <= (max_jint>>LogBytesPerWord) ) {
1093           return x;
1094         }
1095       }
1096     }
1097   }
1098 
1099   return (phase->type(in(2))->higher_equal(TypeInt::ZERO)) ? in(1) : this;
1100 }
1101 
1102 //------------------------------Ideal------------------------------------------
1103 Node *URShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
1104   const TypeInt *t2 = phase->type( in(2) )->isa_int();
1105   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
1106   const int con = t2->get_con() & 31; // Shift count is always masked
1107   if ( con == 0 ) return NULL;  // let Identity() handle a 0 shift count
1108   // We'll be wanting the right-shift amount as a mask of that many bits
1109   const int mask = right_n_bits(BitsPerJavaInteger - con);
1110 
1111   int in1_op = in(1)->Opcode();
1112 
1113   // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32
1114   if( in1_op == Op_URShiftI ) {
1115     const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int();
1116     if( t12 && t12->is_con() ) { // Right input is a constant
1117       assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" );
1118       const int con2 = t12->get_con() & 31; // Shift count is always masked
1119       const int con3 = con+con2;
1120       if( con3 < 32 )           // Only merge shifts if total is < 32
1121         return new (phase->C) URShiftINode( in(1)->in(1), phase->intcon(con3) );
1122     }
1123   }
1124 
1125   // Check for ((x << z) + Y) >>> z.  Replace with x + con>>>z
1126   // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1127   // If Q is "X << z" the rounding is useless.  Look for patterns like
1128   // ((X<<Z) + Y) >>> Z  and replace with (X + Y>>>Z) & Z-mask.
1129   Node *add = in(1);
1130   if( in1_op == Op_AddI ) {
1131     Node *lshl = add->in(1);
1132     if( lshl->Opcode() == Op_LShiftI &&
1133         phase->type(lshl->in(2)) == t2 ) {
1134       Node *y_z = phase->transform( new (phase->C) URShiftINode(add->in(2),in(2)) );
1135       Node *sum = phase->transform( new (phase->C) AddINode( lshl->in(1), y_z ) );
1136       return new (phase->C) AndINode( sum, phase->intcon(mask) );
1137     }
1138   }
1139 
1140   // Check for (x & mask) >>> z.  Replace with (x >>> z) & (mask >>> z)
1141   // This shortens the mask.  Also, if we are extracting a high byte and
1142   // storing it to a buffer, the mask will be removed completely.
1143   Node *andi = in(1);
1144   if( in1_op == Op_AndI ) {
1145     const TypeInt *t3 = phase->type( andi->in(2) )->isa_int();
1146     if( t3 && t3->is_con() ) { // Right input is a constant
1147       jint mask2 = t3->get_con();
1148       mask2 >>= con;  // *signed* shift downward (high-order zeroes do not help)
1149       Node *newshr = phase->transform( new (phase->C) URShiftINode(andi->in(1), in(2)) );
1150       return new (phase->C) AndINode(newshr, phase->intcon(mask2));
1151       // The negative values are easier to materialize than positive ones.
1152       // A typical case from address arithmetic is ((x & ~15) >> 4).
1153       // It's better to change that to ((x >> 4) & ~0) versus
1154       // ((x >> 4) & 0x0FFFFFFF).  The difference is greatest in LP64.
1155     }
1156   }
1157 
1158   // Check for "(X << z ) >>> z" which simply zero-extends
1159   Node *shl = in(1);
1160   if( in1_op == Op_LShiftI &&
1161       phase->type(shl->in(2)) == t2 )
1162     return new (phase->C) AndINode( shl->in(1), phase->intcon(mask) );
1163 
1164   return NULL;
1165 }
1166 
1167 //------------------------------Value------------------------------------------
1168 // A URShiftINode shifts its input2 right by input1 amount.
1169 const Type *URShiftINode::Value( PhaseTransform *phase ) const {
1170   // (This is a near clone of RShiftINode::Value.)
1171   const Type *t1 = phase->type( in(1) );
1172   const Type *t2 = phase->type( in(2) );
1173   // Either input is TOP ==> the result is TOP
1174   if( t1 == Type::TOP ) return Type::TOP;
1175   if( t2 == Type::TOP ) return Type::TOP;
1176 
1177   // Left input is ZERO ==> the result is ZERO.
1178   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
1179   // Shift by zero does nothing
1180   if( t2 == TypeInt::ZERO ) return t1;
1181 
1182   // Either input is BOTTOM ==> the result is BOTTOM
1183   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1184     return TypeInt::INT;
1185 
1186   if (t2 == TypeInt::INT)
1187     return TypeInt::INT;
1188 
1189   const TypeInt *r1 = t1->is_int();     // Handy access
1190   const TypeInt *r2 = t2->is_int();     // Handy access
1191 
1192   if (r2->is_con()) {
1193     uint shift = r2->get_con();
1194     shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
1195     // Shift by a multiple of 32 does nothing:
1196     if (shift == 0)  return t1;
1197     // Calculate reasonably aggressive bounds for the result.
1198     jint lo = (juint)r1->_lo >> (juint)shift;
1199     jint hi = (juint)r1->_hi >> (juint)shift;
1200     if (r1->_hi >= 0 && r1->_lo < 0) {
1201       // If the type has both negative and positive values,
1202       // there are two separate sub-domains to worry about:
1203       // The positive half and the negative half.
1204       jint neg_lo = lo;
1205       jint neg_hi = (juint)-1 >> (juint)shift;
1206       jint pos_lo = (juint) 0 >> (juint)shift;
1207       jint pos_hi = hi;
1208       lo = MIN2(neg_lo, pos_lo);  // == 0
1209       hi = MAX2(neg_hi, pos_hi);  // == -1 >>> shift;
1210     }
1211     assert(lo <= hi, "must have valid bounds");
1212     const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1213     #ifdef ASSERT
1214     // Make sure we get the sign-capture idiom correct.
1215     if (shift == BitsPerJavaInteger-1) {
1216       if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0");
1217       if (r1->_hi < 0)  assert(ti == TypeInt::ONE,  ">>>31 of - is +1");
1218     }
1219     #endif
1220     return ti;
1221   }
1222 
1223   //
1224   // Do not support shifted oops in info for GC
1225   //
1226   // else if( t1->base() == Type::InstPtr ) {
1227   //
1228   //   const TypeInstPtr *o = t1->is_instptr();
1229   //   if( t1->singleton() )
1230   //     return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
1231   // }
1232   // else if( t1->base() == Type::KlassPtr ) {
1233   //   const TypeKlassPtr *o = t1->is_klassptr();
1234   //   if( t1->singleton() )
1235   //     return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
1236   // }
1237 
1238   return TypeInt::INT;
1239 }
1240 
1241 //=============================================================================
1242 //------------------------------Identity---------------------------------------
1243 Node *URShiftLNode::Identity( PhaseTransform *phase ) {
1244   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
1245   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
1246 }
1247 
1248 //------------------------------Ideal------------------------------------------
1249 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1250   const TypeInt *t2 = phase->type( in(2) )->isa_int();
1251   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
1252   const int con = t2->get_con() & ( BitsPerLong - 1 ); // Shift count is always masked
1253   if ( con == 0 ) return NULL;  // let Identity() handle a 0 shift count
1254                               // note: mask computation below does not work for 0 shift count
1255   // We'll be wanting the right-shift amount as a mask of that many bits
1256   const jlong mask = (((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) -1);
1257 
1258   // Check for ((x << z) + Y) >>> z.  Replace with x + con>>>z
1259   // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1260   // If Q is "X << z" the rounding is useless.  Look for patterns like
1261   // ((X<<Z) + Y) >>> Z  and replace with (X + Y>>>Z) & Z-mask.
1262   Node *add = in(1);
1263   if( add->Opcode() == Op_AddL ) {
1264     Node *lshl = add->in(1);
1265     if( lshl->Opcode() == Op_LShiftL &&
1266         phase->type(lshl->in(2)) == t2 ) {
1267       Node *y_z = phase->transform( new (phase->C) URShiftLNode(add->in(2),in(2)) );
1268       Node *sum = phase->transform( new (phase->C) AddLNode( lshl->in(1), y_z ) );
1269       return new (phase->C) AndLNode( sum, phase->longcon(mask) );
1270     }
1271   }
1272 
1273   // Check for (x & mask) >>> z.  Replace with (x >>> z) & (mask >>> z)
1274   // This shortens the mask.  Also, if we are extracting a high byte and
1275   // storing it to a buffer, the mask will be removed completely.
1276   Node *andi = in(1);
1277   if( andi->Opcode() == Op_AndL ) {
1278     const TypeLong *t3 = phase->type( andi->in(2) )->isa_long();
1279     if( t3 && t3->is_con() ) { // Right input is a constant
1280       jlong mask2 = t3->get_con();
1281       mask2 >>= con;  // *signed* shift downward (high-order zeroes do not help)
1282       Node *newshr = phase->transform( new (phase->C) URShiftLNode(andi->in(1), in(2)) );
1283       return new (phase->C) AndLNode(newshr, phase->longcon(mask2));
1284     }
1285   }
1286 
1287   // Check for "(X << z ) >>> z" which simply zero-extends
1288   Node *shl = in(1);
1289   if( shl->Opcode() == Op_LShiftL &&
1290       phase->type(shl->in(2)) == t2 )
1291     return new (phase->C) AndLNode( shl->in(1), phase->longcon(mask) );
1292 
1293   return NULL;
1294 }
1295 
1296 //------------------------------Value------------------------------------------
1297 // A URShiftINode shifts its input2 right by input1 amount.
1298 const Type *URShiftLNode::Value( PhaseTransform *phase ) const {
1299   // (This is a near clone of RShiftLNode::Value.)
1300   const Type *t1 = phase->type( in(1) );
1301   const Type *t2 = phase->type( in(2) );
1302   // Either input is TOP ==> the result is TOP
1303   if( t1 == Type::TOP ) return Type::TOP;
1304   if( t2 == Type::TOP ) return Type::TOP;
1305 
1306   // Left input is ZERO ==> the result is ZERO.
1307   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
1308   // Shift by zero does nothing
1309   if( t2 == TypeInt::ZERO ) return t1;
1310 
1311   // Either input is BOTTOM ==> the result is BOTTOM
1312   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1313     return TypeLong::LONG;
1314 
1315   if (t2 == TypeInt::INT)
1316     return TypeLong::LONG;
1317 
1318   const TypeLong *r1 = t1->is_long(); // Handy access
1319   const TypeInt  *r2 = t2->is_int (); // Handy access
1320 
1321   if (r2->is_con()) {
1322     uint shift = r2->get_con();
1323     shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
1324     // Shift by a multiple of 64 does nothing:
1325     if (shift == 0)  return t1;
1326     // Calculate reasonably aggressive bounds for the result.
1327     jlong lo = (julong)r1->_lo >> (juint)shift;
1328     jlong hi = (julong)r1->_hi >> (juint)shift;
1329     if (r1->_hi >= 0 && r1->_lo < 0) {
1330       // If the type has both negative and positive values,
1331       // there are two separate sub-domains to worry about:
1332       // The positive half and the negative half.
1333       jlong neg_lo = lo;
1334       jlong neg_hi = (julong)-1 >> (juint)shift;
1335       jlong pos_lo = (julong) 0 >> (juint)shift;
1336       jlong pos_hi = hi;
1337       //lo = MIN2(neg_lo, pos_lo);  // == 0
1338       lo = neg_lo < pos_lo ? neg_lo : pos_lo;
1339       //hi = MAX2(neg_hi, pos_hi);  // == -1 >>> shift;
1340       hi = neg_hi > pos_hi ? neg_hi : pos_hi;
1341     }
1342     assert(lo <= hi, "must have valid bounds");
1343     const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1344     #ifdef ASSERT
1345     // Make sure we get the sign-capture idiom correct.
1346     if (shift == BitsPerJavaLong - 1) {
1347       if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0");
1348       if (r1->_hi < 0)  assert(tl == TypeLong::ONE,  ">>>63 of - is +1");
1349     }
1350     #endif
1351     return tl;
1352   }
1353 
1354   return TypeLong::LONG;                // Give up
1355 }