jdk8-mips64-public/hotspot: src/share/vm/opto/mulnode.cpp@bd441136a5ce (annotated)

src/share/vm/opto/mulnode.cpp@bd441136a5ce (annotated)

src/share/vm/opto/mulnode.cpp

Thu, 19 Mar 2009 09:13:24 -0700

author: kvn
date: Thu, 19 Mar 2009 09:13:24 -0700
changeset 1082: bd441136a5ce
parent 1059: 337400e7a5dd
child 1259: 18a08a7e16b5
permissions: -rw-r--r--

Merge

 /*
  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 // Portions of code courtesy of Clifford Click
 #include "incls/_precompiled.incl"
 #include "incls/_mulnode.cpp.incl"
 //=============================================================================
 //------------------------------hash-------------------------------------------
 // Hash function over MulNodes.  Needs to be commutative; i.e., I swap
 // (commute) inputs to MulNodes willy-nilly so the hash function must return
 // the same value in the presence of edge swapping.
 uint MulNode::hash() const {
   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
 }
 //------------------------------Identity---------------------------------------
 // Multiplying a one preserves the other argument
 Node *MulNode::Identity( PhaseTransform *phase ) {
   register const Type *one = mul_id();  // The multiplicative identity
   if( phase->type( in(1) )->higher_equal( one ) ) return in(2);
   if( phase->type( in(2) )->higher_equal( one ) ) return in(1);
   return this;
 }
 //------------------------------Ideal------------------------------------------
 // We also canonicalize the Node, moving constants to the right input,
 // and flatten expressions (so that 1+x+2 becomes x+3).
 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   Node *progress = NULL;        // Progress flag
   // We are OK if right is a constant, or right is a load and
   // left is a non-constant.
   if( !(t2->singleton() ||
         (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) {
     if( t1->singleton() ||       // Left input is a constant?
         // Otherwise, sort inputs (commutativity) to help value numbering.
         (in(1)->_idx > in(2)->_idx) ) {
       swap_edges(1, 2);
       const Type *t = t1;
       t1 = t2;
       t2 = t;
       progress = this;            // Made progress
     }
   }
   // If the right input is a constant, and the left input is a product of a
   // constant, flatten the expression tree.
   uint op = Opcode();
   if( t2->singleton() &&        // Right input is a constant?
       op != Op_MulF &&          // Float & double cannot reassociate
       op != Op_MulD ) {
     if( t2 == Type::TOP ) return NULL;
     Node *mul1 = in(1);
 #ifdef ASSERT
     // Check for dead loop
     int   op1 = mul1->Opcode();
     if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) ||
         ( op1 == mul_opcode() || op1 == add_opcode() ) &&
         ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) ||
           phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) )
       assert(false, "dead loop in MulNode::Ideal");
 #endif
     if( mul1->Opcode() == mul_opcode() ) {  // Left input is a multiply?
       // Mul of a constant?
       const Type *t12 = phase->type( mul1->in(2) );
       if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
         // Compute new constant; check for overflow
         const Type *tcon01 = mul1->as_Mul()->mul_ring(t2,t12);
         if( tcon01->singleton() ) {
           // The Mul of the flattened expression
           set_req(1, mul1->in(1));
           set_req(2, phase->makecon( tcon01 ));
           t2 = tcon01;
           progress = this;      // Made progress
         }
       }
     }
     // If the right input is a constant, and the left input is an add of a
     // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0
     const Node *add1 = in(1);
     if( add1->Opcode() == add_opcode() ) {      // Left input is an add?
       // Add of a constant?
       const Type *t12 = phase->type( add1->in(2) );
       if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
         assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" );
         // Compute new constant; check for overflow
         const Type *tcon01 = mul_ring(t2,t12);
         if( tcon01->singleton() ) {
         // Convert (X+con1)*con0 into X*con0
           Node *mul = clone();    // mul = ()*con0
           mul->set_req(1,add1->in(1));  // mul = X*con0
           mul = phase->transform(mul);
           Node *add2 = add1->clone();
           add2->set_req(1, mul);        // X*con0 + con0*con1
           add2->set_req(2, phase->makecon(tcon01) );
           progress = add2;
         }
       }
     } // End of is left input an add
   } // End of is right input a Mul
   return progress;
 }
 //------------------------------Value-----------------------------------------
 const Type *MulNode::Value( PhaseTransform *phase ) const {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Either input is ZERO ==> the result is ZERO.
   // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0
   int op = Opcode();
   if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) {
     const Type *zero = add_id();        // The multiplicative zero
     if( t1->higher_equal( zero ) ) return zero;
     if( t2->higher_equal( zero ) ) return zero;
   }
   // Either input is BOTTOM ==> the result is the local BOTTOM
   if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
     return bottom_type();
 #if defined(IA32)
   // Can't trust native compilers to properly fold strict double
   // multiplication with round-to-zero on this platform.
   if (op == Op_MulD && phase->C->method()->is_strict()) {
     return TypeD::DOUBLE;
   }
 #endif
   return mul_ring(t1,t2);            // Local flavor of type multiplication
 }
 //=============================================================================
 //------------------------------Ideal------------------------------------------
 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // Swap constant to right
   jint con;
   if ((con = in(1)->find_int_con(0)) != 0) {
     swap_edges(1, 2);
     // Finish rest of method to use info in 'con'
   } else if ((con = in(2)->find_int_con(0)) == 0) {
     return MulNode::Ideal(phase, can_reshape);
   }
   // Now we have a constant Node on the right and the constant in con
   if( con == 0 ) return NULL;   // By zero is handled by Value call
   if( con == 1 ) return NULL;   // By one  is handled by Identity call
   // Check for negative constant; if so negate the final result
   bool sign_flip = false;
   if( con < 0 ) {
     con = -con;
     sign_flip = true;
   }
   // Get low bit; check for being the only bit
   Node *res = NULL;
   jint bit1 = con & -con;       // Extract low bit
   if( bit1 == con ) {           // Found a power of 2?
     res = new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) );
   } else {
     // Check for constant with 2 bits set
     jint bit2 = con-bit1;
     bit2 = bit2 & -bit2;          // Extract 2nd bit
     if( bit2 + bit1 == con ) {    // Found all bits in con?
       Node *n1 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) );
       Node *n2 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) );
       res = new (phase->C, 3) AddINode( n2, n1 );
     } else if (is_power_of_2(con+1)) {
       // Sleezy: power-of-2 -1.  Next time be generic.
       jint temp = (jint) (con + 1);
       Node *n1 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) );
       res = new (phase->C, 3) SubINode( n1, in(1) );
     } else {
       return MulNode::Ideal(phase, can_reshape);
     }
   }
   if( sign_flip ) {             // Need to negate result?
     res = phase->transform(res);// Transform, before making the zero con
     res = new (phase->C, 3) SubINode(phase->intcon(0),res);
   }
   return res;                   // Return final result
 }
 //------------------------------mul_ring---------------------------------------
 // Compute the product type of two integer ranges into this node.
 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const {
   const TypeInt *r0 = t0->is_int(); // Handy access
   const TypeInt *r1 = t1->is_int();
   // Fetch endpoints of all ranges
   int32 lo0 = r0->_lo;
   double a = (double)lo0;
   int32 hi0 = r0->_hi;
   double b = (double)hi0;
   int32 lo1 = r1->_lo;
   double c = (double)lo1;
   int32 hi1 = r1->_hi;
   double d = (double)hi1;
   // Compute all endpoints & check for overflow
   int32 A = lo0*lo1;
   if( (double)A != a*c ) return TypeInt::INT; // Overflow?
   int32 B = lo0*hi1;
   if( (double)B != a*d ) return TypeInt::INT; // Overflow?
   int32 C = hi0*lo1;
   if( (double)C != b*c ) return TypeInt::INT; // Overflow?
   int32 D = hi0*hi1;
   if( (double)D != b*d ) return TypeInt::INT; // Overflow?
   if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
   else { lo0 = B; hi0 = A; }
   if( C < D ) {
     if( C < lo0 ) lo0 = C;
     if( D > hi0 ) hi0 = D;
   } else {
     if( D < lo0 ) lo0 = D;
     if( C > hi0 ) hi0 = C;
   }
   return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
 }
 //=============================================================================
 //------------------------------Ideal------------------------------------------
 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // Swap constant to right
   jlong con;
   if ((con = in(1)->find_long_con(0)) != 0) {
     swap_edges(1, 2);
     // Finish rest of method to use info in 'con'
   } else if ((con = in(2)->find_long_con(0)) == 0) {
     return MulNode::Ideal(phase, can_reshape);
   }
   // Now we have a constant Node on the right and the constant in con
   if( con == CONST64(0) ) return NULL;  // By zero is handled by Value call
   if( con == CONST64(1) ) return NULL;  // By one  is handled by Identity call
   // Check for negative constant; if so negate the final result
   bool sign_flip = false;
   if( con < 0 ) {
     con = -con;
     sign_flip = true;
   }
   // Get low bit; check for being the only bit
   Node *res = NULL;
   jlong bit1 = con & -con;      // Extract low bit
   if( bit1 == con ) {           // Found a power of 2?
     res = new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) );
   } else {
     // Check for constant with 2 bits set
     jlong bit2 = con-bit1;
     bit2 = bit2 & -bit2;          // Extract 2nd bit
     if( bit2 + bit1 == con ) {    // Found all bits in con?
       Node *n1 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) );
       Node *n2 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) );
       res = new (phase->C, 3) AddLNode( n2, n1 );
     } else if (is_power_of_2_long(con+1)) {
       // Sleezy: power-of-2 -1.  Next time be generic.
       jlong temp = (jlong) (con + 1);
       Node *n1 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) );
       res = new (phase->C, 3) SubLNode( n1, in(1) );
     } else {
       return MulNode::Ideal(phase, can_reshape);
     }
   }
   if( sign_flip ) {             // Need to negate result?
     res = phase->transform(res);// Transform, before making the zero con
     res = new (phase->C, 3) SubLNode(phase->longcon(0),res);
   }
   return res;                   // Return final result
 }
 //------------------------------mul_ring---------------------------------------
 // Compute the product type of two integer ranges into this node.
 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const {
   const TypeLong *r0 = t0->is_long(); // Handy access
   const TypeLong *r1 = t1->is_long();
   // Fetch endpoints of all ranges
   jlong lo0 = r0->_lo;
   double a = (double)lo0;
   jlong hi0 = r0->_hi;
   double b = (double)hi0;
   jlong lo1 = r1->_lo;
   double c = (double)lo1;
   jlong hi1 = r1->_hi;
   double d = (double)hi1;
   // Compute all endpoints & check for overflow
   jlong A = lo0*lo1;
   if( (double)A != a*c ) return TypeLong::LONG; // Overflow?
   jlong B = lo0*hi1;
   if( (double)B != a*d ) return TypeLong::LONG; // Overflow?
   jlong C = hi0*lo1;
   if( (double)C != b*c ) return TypeLong::LONG; // Overflow?
   jlong D = hi0*hi1;
   if( (double)D != b*d ) return TypeLong::LONG; // Overflow?
   if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
   else { lo0 = B; hi0 = A; }
   if( C < D ) {
     if( C < lo0 ) lo0 = C;
     if( D > hi0 ) hi0 = D;
   } else {
     if( D < lo0 ) lo0 = D;
     if( C > hi0 ) hi0 = C;
   }
   return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
 }
 //=============================================================================
 //------------------------------mul_ring---------------------------------------
 // Compute the product type of two double ranges into this node.
 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const {
   if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT;
   return TypeF::make( t0->getf() * t1->getf() );
 }
 //=============================================================================
 //------------------------------mul_ring---------------------------------------
 // Compute the product type of two double ranges into this node.
 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const {
   if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE;
   // We must be multiplying 2 double constants.
   return TypeD::make( t0->getd() * t1->getd() );
 }
 //=============================================================================
 //------------------------------Value------------------------------------------
 const Type *MulHiLNode::Value( PhaseTransform *phase ) const {
   // Either input is TOP ==> the result is TOP
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Either input is BOTTOM ==> the result is the local BOTTOM
   const Type *bot = bottom_type();
   if( (t1 == bot) || (t2 == bot) ||
       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
     return bot;
   // It is not worth trying to constant fold this stuff!
   return TypeLong::LONG;
 }
 //=============================================================================
 //------------------------------mul_ring---------------------------------------
 // Supplied function returns the product of the inputs IN THE CURRENT RING.
 // For the logical operations the ring's MUL is really a logical AND function.
 // This also type-checks the inputs for sanity.  Guaranteed never to
 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const {
   const TypeInt *r0 = t0->is_int(); // Handy access
   const TypeInt *r1 = t1->is_int();
   int widen = MAX2(r0->_widen,r1->_widen);
   // If either input is a constant, might be able to trim cases
   if( !r0->is_con() && !r1->is_con() )
     return TypeInt::INT;        // No constants to be had
   // Both constants?  Return bits
   if( r0->is_con() && r1->is_con() )
     return TypeInt::make( r0->get_con() & r1->get_con() );
   if( r0->is_con() && r0->get_con() > 0 )
     return TypeInt::make(0, r0->get_con(), widen);
   if( r1->is_con() && r1->get_con() > 0 )
     return TypeInt::make(0, r1->get_con(), widen);
   if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) {
     return TypeInt::BOOL;
   }
   return TypeInt::INT;          // No constants to be had
 }
 //------------------------------Identity---------------------------------------
 // Masking off the high bits of an unsigned load is not required
 Node *AndINode::Identity( PhaseTransform *phase ) {
   // x & x => x
   if (phase->eqv(in(1), in(2))) return in(1);
   Node *load = in(1);
   const TypeInt *t2 = phase->type( in(2) )->isa_int();
   if( t2 && t2->is_con() ) {
     int con = t2->get_con();
     // Masking off high bits which are always zero is useless.
     const TypeInt* t1 = phase->type( in(1) )->isa_int();
     if (t1 != NULL && t1->_lo >= 0) {
       jint t1_support = ((jint)1 << (1 + log2_intptr(t1->_hi))) - 1;
       if ((t1_support & con) == t1_support)
         return load;
     }
     uint lop = load->Opcode();
     if( lop == Op_LoadUS &&
         con == 0x0000FFFF )     // Already zero-extended
       return load;
     // Masking off the high bits of a unsigned-shift-right is not
     // needed either.
     if( lop == Op_URShiftI ) {
       const TypeInt *t12 = phase->type( load->in(2) )->isa_int();
       if( t12 && t12->is_con() ) {  // Shift is by a constant
         int shift = t12->get_con();
         shift &= BitsPerJavaInteger - 1;  // semantics of Java shifts
         int mask = max_juint >> shift;
         if( (mask&con) == mask )  // If AND is useless, skip it
           return load;
       }
     }
   }
   return MulNode::Identity(phase);
 }
 //------------------------------Ideal------------------------------------------
 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // Special case constant AND mask
   const TypeInt *t2 = phase->type( in(2) )->isa_int();
   if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
   const int mask = t2->get_con();
   Node *load = in(1);
   uint lop = load->Opcode();
   // Masking bits off of a Character?  Hi bits are already zero.
   if( lop == Op_LoadUS &&
       (mask & 0xFFFF0000) )     // Can we make a smaller mask?
     return new (phase->C, 3) AndINode(load,phase->intcon(mask&0xFFFF));
   // Masking bits off of a Short?  Loading a Character does some masking
   if( lop == Op_LoadS &&
       (mask & 0xFFFF0000) == 0 ) {
     Node *ldus = new (phase->C, 3) LoadUSNode(load->in(MemNode::Control),
                                   load->in(MemNode::Memory),
                                   load->in(MemNode::Address),
                                   load->adr_type());
     ldus = phase->transform(ldus);
     return new (phase->C, 3) AndINode(ldus, phase->intcon(mask&0xFFFF));
   }
   // Masking sign bits off of a Byte?  Do an unsigned byte load.
   if (lop == Op_LoadB && mask == 0x000000FF) {
     return new (phase->C, 3) LoadUBNode(load->in(MemNode::Control),
                                         load->in(MemNode::Memory),
                                         load->in(MemNode::Address),
                                         load->adr_type());
   }
   // Masking sign bits off of a Byte plus additional lower bits?  Do
   // an unsigned byte load plus an and.
   if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
     Node* ldub = new (phase->C, 3) LoadUBNode(load->in(MemNode::Control),
                                               load->in(MemNode::Memory),
                                               load->in(MemNode::Address),
                                               load->adr_type());
     ldub = phase->transform(ldub);
     return new (phase->C, 3) AndINode(ldub, phase->intcon(mask));
   }
   // Masking off sign bits?  Dont make them!
   if( lop == Op_RShiftI ) {
     const TypeInt *t12 = phase->type(load->in(2))->isa_int();
     if( t12 && t12->is_con() ) { // Shift is by a constant
       int shift = t12->get_con();
       shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
       const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift);
       // If the AND'ing of the 2 masks has no bits, then only original shifted
       // bits survive.  NO sign-extension bits survive the maskings.
       if( (sign_bits_mask & mask) == 0 ) {
         // Use zero-fill shift instead
         Node *zshift = phase->transform(new (phase->C, 3) URShiftINode(load->in(1),load->in(2)));
         return new (phase->C, 3) AndINode( zshift, in(2) );
       }
     }
   }
   // Check for 'negate/and-1', a pattern emitted when someone asks for
   // 'mod 2'.  Negate leaves the low order bit unchanged (think: complement
   // plus 1) and the mask is of the low order bit.  Skip the negate.
   if( lop == Op_SubI && mask == 1 && load->in(1) &&
       phase->type(load->in(1)) == TypeInt::ZERO )
     return new (phase->C, 3) AndINode( load->in(2), in(2) );
   return MulNode::Ideal(phase, can_reshape);
 }
 //=============================================================================
 //------------------------------mul_ring---------------------------------------
 // Supplied function returns the product of the inputs IN THE CURRENT RING.
 // For the logical operations the ring's MUL is really a logical AND function.
 // This also type-checks the inputs for sanity.  Guaranteed never to
 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const {
   const TypeLong *r0 = t0->is_long(); // Handy access
   const TypeLong *r1 = t1->is_long();
   int widen = MAX2(r0->_widen,r1->_widen);
   // If either input is a constant, might be able to trim cases
   if( !r0->is_con() && !r1->is_con() )
     return TypeLong::LONG;      // No constants to be had
   // Both constants?  Return bits
   if( r0->is_con() && r1->is_con() )
     return TypeLong::make( r0->get_con() & r1->get_con() );
   if( r0->is_con() && r0->get_con() > 0 )
     return TypeLong::make(CONST64(0), r0->get_con(), widen);
   if( r1->is_con() && r1->get_con() > 0 )
     return TypeLong::make(CONST64(0), r1->get_con(), widen);
   return TypeLong::LONG;        // No constants to be had
 }
 //------------------------------Identity---------------------------------------
 // Masking off the high bits of an unsigned load is not required
 Node *AndLNode::Identity( PhaseTransform *phase ) {
   // x & x => x
   if (phase->eqv(in(1), in(2))) return in(1);
   Node *usr = in(1);
   const TypeLong *t2 = phase->type( in(2) )->isa_long();
   if( t2 && t2->is_con() ) {
     jlong con = t2->get_con();
     // Masking off high bits which are always zero is useless.
     const TypeLong* t1 = phase->type( in(1) )->isa_long();
     if (t1 != NULL && t1->_lo >= 0) {
       jlong t1_support = ((jlong)1 << (1 + log2_long(t1->_hi))) - 1;
       if ((t1_support & con) == t1_support)
         return usr;
     }
     uint lop = usr->Opcode();
     // Masking off the high bits of a unsigned-shift-right is not
     // needed either.
     if( lop == Op_URShiftL ) {
       const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
       if( t12 && t12->is_con() ) {  // Shift is by a constant
         int shift = t12->get_con();
         shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
         jlong mask = max_julong >> shift;
         if( (mask&con) == mask )  // If AND is useless, skip it
           return usr;
       }
     }
   }
   return MulNode::Identity(phase);
 }
 //------------------------------Ideal------------------------------------------
 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // Special case constant AND mask
   const TypeLong *t2 = phase->type( in(2) )->isa_long();
   if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
   const jlong mask = t2->get_con();
   Node* in1 = in(1);
   uint op = in1->Opcode();
   // Masking sign bits off of an integer?  Do an unsigned integer to long load.
   if (op == Op_ConvI2L && in1->in(1)->Opcode() == Op_LoadI && mask == 0x00000000FFFFFFFFL) {
     Node* load = in1->in(1);
     return new (phase->C, 3) LoadUI2LNode(load->in(MemNode::Control),
                                           load->in(MemNode::Memory),
                                           load->in(MemNode::Address),
                                           load->adr_type());
   }
   // Masking off sign bits?  Dont make them!
   if (op == Op_RShiftL) {
     const TypeInt *t12 = phase->type(in1->in(2))->isa_int();
     if( t12 && t12->is_con() ) { // Shift is by a constant
       int shift = t12->get_con();
       shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
       const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
       // If the AND'ing of the 2 masks has no bits, then only original shifted
       // bits survive.  NO sign-extension bits survive the maskings.
       if( (sign_bits_mask & mask) == 0 ) {
         // Use zero-fill shift instead
         Node *zshift = phase->transform(new (phase->C, 3) URShiftLNode(in1->in(1), in1->in(2)));
         return new (phase->C, 3) AndLNode( zshift, in(2) );
       }
     }
   }
   return MulNode::Ideal(phase, can_reshape);
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *LShiftINode::Identity( PhaseTransform *phase ) {
   const TypeInt *ti = phase->type( in(2) )->isa_int();  // shift count is an int
   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this;
 }
 //------------------------------Ideal------------------------------------------
 // If the right input is a constant, and the left input is an add of a
 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   const Type *t  = phase->type( in(2) );
   if( t == Type::TOP ) return NULL;       // Right input is dead
   const TypeInt *t2 = t->isa_int();
   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
   const int con = t2->get_con() & ( BitsPerInt - 1 );  // masked shift count
   if ( con == 0 )  return NULL; // let Identity() handle 0 shift count
   // Left input is an add of a constant?
   Node *add1 = in(1);
   int add1_op = add1->Opcode();
   if( add1_op == Op_AddI ) {    // Left input is an add?
     assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" );
     const TypeInt *t12 = phase->type(add1->in(2))->isa_int();
     if( t12 && t12->is_con() ){ // Left input is an add of a con?
       // Transform is legal, but check for profit.  Avoid breaking 'i2s'
       // and 'i2b' patterns which typically fold into 'StoreC/StoreB'.
       if( con < 16 ) {
         // Compute X << con0
         Node *lsh = phase->transform( new (phase->C, 3) LShiftINode( add1->in(1), in(2) ) );
         // Compute X<<con0 + (con1<<con0)
         return new (phase->C, 3) AddINode( lsh, phase->intcon(t12->get_con() << con));
       }
     }
   }
   // Check for "(x>>c0)<<c0" which just masks off low bits
   if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) &&
       add1->in(2) == in(2) )
     // Convert to "(x & -(1<<c0))"
     return new (phase->C, 3) AndINode(add1->in(1),phase->intcon( -(1<<con)));
   // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
   if( add1_op == Op_AndI ) {
     Node *add2 = add1->in(1);
     int add2_op = add2->Opcode();
     if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) &&
         add2->in(2) == in(2) ) {
       // Convert to "(x & (Y<<c0))"
       Node *y_sh = phase->transform( new (phase->C, 3) LShiftINode( add1->in(2), in(2) ) );
       return new (phase->C, 3) AndINode( add2->in(1), y_sh );
     }
   }
   // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits
   // before shifting them away.
   const jint bits_mask = right_n_bits(BitsPerJavaInteger-con);
   if( add1_op == Op_AndI &&
       phase->type(add1->in(2)) == TypeInt::make( bits_mask ) )
     return new (phase->C, 3) LShiftINode( add1->in(1), in(2) );
   return NULL;
 }
 //------------------------------Value------------------------------------------
 // A LShiftINode shifts its input2 left by input1 amount.
 const Type *LShiftINode::Value( PhaseTransform *phase ) const {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) ||
       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
     return TypeInt::INT;
   const TypeInt *r1 = t1->is_int(); // Handy access
   const TypeInt *r2 = t2->is_int(); // Handy access
   if (!r2->is_con())
     return TypeInt::INT;
   uint shift = r2->get_con();
   shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
   // Shift by a multiple of 32 does nothing:
   if (shift == 0)  return t1;
   // If the shift is a constant, shift the bounds of the type,
   // unless this could lead to an overflow.
   if (!r1->is_con()) {
     jint lo = r1->_lo, hi = r1->_hi;
     if (((lo << shift) >> shift) == lo &&
         ((hi << shift) >> shift) == hi) {
       // No overflow.  The range shifts up cleanly.
       return TypeInt::make((jint)lo << (jint)shift,
                            (jint)hi << (jint)shift,
                            MAX2(r1->_widen,r2->_widen));
     }
     return TypeInt::INT;
   }
   return TypeInt::make( (jint)r1->get_con() << (jint)shift );
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *LShiftLNode::Identity( PhaseTransform *phase ) {
   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
 }
 //------------------------------Ideal------------------------------------------
 // If the right input is a constant, and the left input is an add of a
 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   const Type *t  = phase->type( in(2) );
   if( t == Type::TOP ) return NULL;       // Right input is dead
   const TypeInt *t2 = t->isa_int();
   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
   const int con = t2->get_con() & ( BitsPerLong - 1 );  // masked shift count
   if ( con == 0 ) return NULL;  // let Identity() handle 0 shift count
   // Left input is an add of a constant?
   Node *add1 = in(1);
   int add1_op = add1->Opcode();
   if( add1_op == Op_AddL ) {    // Left input is an add?
     // Avoid dead data cycles from dead loops
     assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" );
     const TypeLong *t12 = phase->type(add1->in(2))->isa_long();
     if( t12 && t12->is_con() ){ // Left input is an add of a con?
       // Compute X << con0
       Node *lsh = phase->transform( new (phase->C, 3) LShiftLNode( add1->in(1), in(2) ) );
       // Compute X<<con0 + (con1<<con0)
       return new (phase->C, 3) AddLNode( lsh, phase->longcon(t12->get_con() << con));
     }
   }
   // Check for "(x>>c0)<<c0" which just masks off low bits
   if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) &&
       add1->in(2) == in(2) )
     // Convert to "(x & -(1<<c0))"
     return new (phase->C, 3) AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con)));
   // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
   if( add1_op == Op_AndL ) {
     Node *add2 = add1->in(1);
     int add2_op = add2->Opcode();
     if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) &&
         add2->in(2) == in(2) ) {
       // Convert to "(x & (Y<<c0))"
       Node *y_sh = phase->transform( new (phase->C, 3) LShiftLNode( add1->in(2), in(2) ) );
       return new (phase->C, 3) AndLNode( add2->in(1), y_sh );
     }
   }
   // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
   // before shifting them away.
   const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) - CONST64(1);
   if( add1_op == Op_AndL &&
       phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
     return new (phase->C, 3) LShiftLNode( add1->in(1), in(2) );
   return NULL;
 }
 //------------------------------Value------------------------------------------
 // A LShiftLNode shifts its input2 left by input1 amount.
 const Type *LShiftLNode::Value( PhaseTransform *phase ) const {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) ||
       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
     return TypeLong::LONG;
   const TypeLong *r1 = t1->is_long(); // Handy access
   const TypeInt  *r2 = t2->is_int();  // Handy access
   if (!r2->is_con())
     return TypeLong::LONG;
   uint shift = r2->get_con();
   shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
   // Shift by a multiple of 64 does nothing:
   if (shift == 0)  return t1;
   // If the shift is a constant, shift the bounds of the type,
   // unless this could lead to an overflow.
   if (!r1->is_con()) {
     jlong lo = r1->_lo, hi = r1->_hi;
     if (((lo << shift) >> shift) == lo &&
         ((hi << shift) >> shift) == hi) {
       // No overflow.  The range shifts up cleanly.
       return TypeLong::make((jlong)lo << (jint)shift,
                             (jlong)hi << (jint)shift,
                             MAX2(r1->_widen,r2->_widen));
     }
     return TypeLong::LONG;
   }
   return TypeLong::make( (jlong)r1->get_con() << (jint)shift );
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *RShiftINode::Identity( PhaseTransform *phase ) {
   const TypeInt *t2 = phase->type(in(2))->isa_int();
   if( !t2 ) return this;
   if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 )
     return in(1);
   // Check for useless sign-masking
   if( in(1)->Opcode() == Op_LShiftI &&
       in(1)->req() == 3 &&
       in(1)->in(2) == in(2) &&
       t2->is_con() ) {
     uint shift = t2->get_con();
     shift &= BitsPerJavaInteger-1; // semantics of Java shifts
     // Compute masks for which this shifting doesn't change
     int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000
     int hi = ~lo;               // 00007FFF
     const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int();
     if( !t11 ) return this;
     // Does actual value fit inside of mask?
     if( lo <= t11->_lo && t11->_hi <= hi )
       return in(1)->in(1);      // Then shifting is a nop
   }
   return this;
 }
 //------------------------------Ideal------------------------------------------
 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   // Inputs may be TOP if they are dead.
   const TypeInt *t1 = phase->type( in(1) )->isa_int();
   if( !t1 ) return NULL;        // Left input is an integer
   const TypeInt *t2 = phase->type( in(2) )->isa_int();
   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
   const TypeInt *t3;  // type of in(1).in(2)
   int shift = t2->get_con();
   shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
   if ( shift == 0 ) return NULL;  // let Identity() handle 0 shift count
   // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller.
   // Such expressions arise normally from shift chains like (byte)(x >> 24).
   const Node *mask = in(1);
   if( mask->Opcode() == Op_AndI &&
       (t3 = phase->type(mask->in(2))->isa_int()) &&
       t3->is_con() ) {
     Node *x = mask->in(1);
     jint maskbits = t3->get_con();
     // Convert to "(x >> shift) & (mask >> shift)"
     Node *shr_nomask = phase->transform( new (phase->C, 3) RShiftINode(mask->in(1), in(2)) );
     return new (phase->C, 3) AndINode(shr_nomask, phase->intcon( maskbits >> shift));
   }
   // Check for "(short[i] <<16)>>16" which simply sign-extends
   const Node *shl = in(1);
   if( shl->Opcode() != Op_LShiftI ) return NULL;
   if( shift == 16 &&
       (t3 = phase->type(shl->in(2))->isa_int()) &&
       t3->is_con(16) ) {
     Node *ld = shl->in(1);
     if( ld->Opcode() == Op_LoadS ) {
       // Sign extension is just useless here.  Return a RShiftI of zero instead
       // returning 'ld' directly.  We cannot return an old Node directly as
       // that is the job of 'Identity' calls and Identity calls only work on
       // direct inputs ('ld' is an extra Node removed from 'this').  The
       // combined optimization requires Identity only return direct inputs.
       set_req(1, ld);
       set_req(2, phase->intcon(0));
       return this;
     }
     else if( ld->Opcode() == Op_LoadUS )
       // Replace zero-extension-load with sign-extension-load
       return new (phase->C, 3) LoadSNode( ld->in(MemNode::Control),
                                 ld->in(MemNode::Memory),
                                 ld->in(MemNode::Address),
                                 ld->adr_type());
   }
   // Check for "(byte[i] <<24)>>24" which simply sign-extends
   if( shift == 24 &&
       (t3 = phase->type(shl->in(2))->isa_int()) &&
       t3->is_con(24) ) {
     Node *ld = shl->in(1);
     if( ld->Opcode() == Op_LoadB ) {
       // Sign extension is just useless here
       set_req(1, ld);
       set_req(2, phase->intcon(0));
       return this;
     }
   }
   return NULL;
 }
 //------------------------------Value------------------------------------------
 // A RShiftINode shifts its input2 right by input1 amount.
 const Type *RShiftINode::Value( PhaseTransform *phase ) const {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
     return TypeInt::INT;
   if (t2 == TypeInt::INT)
     return TypeInt::INT;
   const TypeInt *r1 = t1->is_int(); // Handy access
   const TypeInt *r2 = t2->is_int(); // Handy access
   // If the shift is a constant, just shift the bounds of the type.
   // For example, if the shift is 31, we just propagate sign bits.
   if (r2->is_con()) {
     uint shift = r2->get_con();
     shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
     // Shift by a multiple of 32 does nothing:
     if (shift == 0)  return t1;
     // Calculate reasonably aggressive bounds for the result.
     // This is necessary if we are to correctly type things
     // like (x<<24>>24) == ((byte)x).
     jint lo = (jint)r1->_lo >> (jint)shift;
     jint hi = (jint)r1->_hi >> (jint)shift;
     assert(lo <= hi, "must have valid bounds");
     const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
 #ifdef ASSERT
     // Make sure we get the sign-capture idiom correct.
     if (shift == BitsPerJavaInteger-1) {
       if (r1->_lo >= 0) assert(ti == TypeInt::ZERO,    ">>31 of + is  0");
       if (r1->_hi <  0) assert(ti == TypeInt::MINUS_1, ">>31 of - is -1");
     }
 #endif
     return ti;
   }
   if( !r1->is_con() || !r2->is_con() )
     return TypeInt::INT;
   // Signed shift right
   return TypeInt::make( r1->get_con() >> (r2->get_con()&31) );
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *RShiftLNode::Identity( PhaseTransform *phase ) {
   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
 }
 //------------------------------Value------------------------------------------
 // A RShiftLNode shifts its input2 right by input1 amount.
 const Type *RShiftLNode::Value( PhaseTransform *phase ) const {
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
     return TypeLong::LONG;
   if (t2 == TypeInt::INT)
     return TypeLong::LONG;
   const TypeLong *r1 = t1->is_long(); // Handy access
   const TypeInt  *r2 = t2->is_int (); // Handy access
   // If the shift is a constant, just shift the bounds of the type.
   // For example, if the shift is 63, we just propagate sign bits.
   if (r2->is_con()) {
     uint shift = r2->get_con();
     shift &= (2*BitsPerJavaInteger)-1;  // semantics of Java shifts
     // Shift by a multiple of 64 does nothing:
     if (shift == 0)  return t1;
     // Calculate reasonably aggressive bounds for the result.
     // This is necessary if we are to correctly type things
     // like (x<<24>>24) == ((byte)x).
     jlong lo = (jlong)r1->_lo >> (jlong)shift;
     jlong hi = (jlong)r1->_hi >> (jlong)shift;
     assert(lo <= hi, "must have valid bounds");
     const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
     #ifdef ASSERT
     // Make sure we get the sign-capture idiom correct.
     if (shift == (2*BitsPerJavaInteger)-1) {
       if (r1->_lo >= 0) assert(tl == TypeLong::ZERO,    ">>63 of + is 0");
       if (r1->_hi < 0)  assert(tl == TypeLong::MINUS_1, ">>63 of - is -1");
     }
     #endif
     return tl;
   }
   return TypeLong::LONG;                // Give up
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *URShiftINode::Identity( PhaseTransform *phase ) {
   const TypeInt *ti = phase->type( in(2) )->isa_int();
   if ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) return in(1);
   // Check for "((x << LogBytesPerWord) + (wordSize-1)) >> LogBytesPerWord" which is just "x".
   // Happens during new-array length computation.
   // Safe if 'x' is in the range [0..(max_int>>LogBytesPerWord)]
   Node *add = in(1);
   if( add->Opcode() == Op_AddI ) {
     const TypeInt *t2  = phase->type(add->in(2))->isa_int();
     if( t2 && t2->is_con(wordSize - 1) &&
         add->in(1)->Opcode() == Op_LShiftI ) {
       // Check that shift_counts are LogBytesPerWord
       Node          *lshift_count   = add->in(1)->in(2);
       const TypeInt *t_lshift_count = phase->type(lshift_count)->isa_int();
       if( t_lshift_count && t_lshift_count->is_con(LogBytesPerWord) &&
           t_lshift_count == phase->type(in(2)) ) {
         Node          *x   = add->in(1)->in(1);
         const TypeInt *t_x = phase->type(x)->isa_int();
         if( t_x != NULL && 0 <= t_x->_lo && t_x->_hi <= (max_jint>>LogBytesPerWord) ) {
           return x;
         }
       }
     }
   }
   return (phase->type(in(2))->higher_equal(TypeInt::ZERO)) ? in(1) : this;
 }
 //------------------------------Ideal------------------------------------------
 Node *URShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   const TypeInt *t2 = phase->type( in(2) )->isa_int();
   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
   const int con = t2->get_con() & 31; // Shift count is always masked
   if ( con == 0 ) return NULL;  // let Identity() handle a 0 shift count
   // We'll be wanting the right-shift amount as a mask of that many bits
   const int mask = right_n_bits(BitsPerJavaInteger - con);
   int in1_op = in(1)->Opcode();
   // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32
   if( in1_op == Op_URShiftI ) {
     const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int();
     if( t12 && t12->is_con() ) { // Right input is a constant
       assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" );
       const int con2 = t12->get_con() & 31; // Shift count is always masked
       const int con3 = con+con2;
       if( con3 < 32 )           // Only merge shifts if total is < 32
         return new (phase->C, 3) URShiftINode( in(1)->in(1), phase->intcon(con3) );
     }
   }
   // Check for ((x << z) + Y) >>> z.  Replace with x + con>>>z
   // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
   // If Q is "X << z" the rounding is useless.  Look for patterns like
   // ((X<<Z) + Y) >>> Z  and replace with (X + Y>>>Z) & Z-mask.
   Node *add = in(1);
   if( in1_op == Op_AddI ) {
     Node *lshl = add->in(1);
     if( lshl->Opcode() == Op_LShiftI &&
         phase->type(lshl->in(2)) == t2 ) {
       Node *y_z = phase->transform( new (phase->C, 3) URShiftINode(add->in(2),in(2)) );
       Node *sum = phase->transform( new (phase->C, 3) AddINode( lshl->in(1), y_z ) );
       return new (phase->C, 3) AndINode( sum, phase->intcon(mask) );
     }
   }
   // Check for (x & mask) >>> z.  Replace with (x >>> z) & (mask >>> z)
   // This shortens the mask.  Also, if we are extracting a high byte and
   // storing it to a buffer, the mask will be removed completely.
   Node *andi = in(1);
   if( in1_op == Op_AndI ) {
     const TypeInt *t3 = phase->type( andi->in(2) )->isa_int();
     if( t3 && t3->is_con() ) { // Right input is a constant
       jint mask2 = t3->get_con();
       mask2 >>= con;  // *signed* shift downward (high-order zeroes do not help)
       Node *newshr = phase->transform( new (phase->C, 3) URShiftINode(andi->in(1), in(2)) );
       return new (phase->C, 3) AndINode(newshr, phase->intcon(mask2));
       // The negative values are easier to materialize than positive ones.
       // A typical case from address arithmetic is ((x & ~15) >> 4).
       // It's better to change that to ((x >> 4) & ~0) versus
       // ((x >> 4) & 0x0FFFFFFF).  The difference is greatest in LP64.
     }
   }
   // Check for "(X << z ) >>> z" which simply zero-extends
   Node *shl = in(1);
   if( in1_op == Op_LShiftI &&
       phase->type(shl->in(2)) == t2 )
     return new (phase->C, 3) AndINode( shl->in(1), phase->intcon(mask) );
   return NULL;
 }
 //------------------------------Value------------------------------------------
 // A URShiftINode shifts its input2 right by input1 amount.
 const Type *URShiftINode::Value( PhaseTransform *phase ) const {
   // (This is a near clone of RShiftINode::Value.)
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
     return TypeInt::INT;
   if (t2 == TypeInt::INT)
     return TypeInt::INT;
   const TypeInt *r1 = t1->is_int();     // Handy access
   const TypeInt *r2 = t2->is_int();     // Handy access
   if (r2->is_con()) {
     uint shift = r2->get_con();
     shift &= BitsPerJavaInteger-1;  // semantics of Java shifts
     // Shift by a multiple of 32 does nothing:
     if (shift == 0)  return t1;
     // Calculate reasonably aggressive bounds for the result.
     jint lo = (juint)r1->_lo >> (juint)shift;
     jint hi = (juint)r1->_hi >> (juint)shift;
     if (r1->_hi >= 0 && r1->_lo < 0) {
       // If the type has both negative and positive values,
       // there are two separate sub-domains to worry about:
       // The positive half and the negative half.
       jint neg_lo = lo;
       jint neg_hi = (juint)-1 >> (juint)shift;
       jint pos_lo = (juint) 0 >> (juint)shift;
       jint pos_hi = hi;
       lo = MIN2(neg_lo, pos_lo);  // == 0
       hi = MAX2(neg_hi, pos_hi);  // == -1 >>> shift;
     }
     assert(lo <= hi, "must have valid bounds");
     const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
     #ifdef ASSERT
     // Make sure we get the sign-capture idiom correct.
     if (shift == BitsPerJavaInteger-1) {
       if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0");
       if (r1->_hi < 0)  assert(ti == TypeInt::ONE,  ">>>31 of - is +1");
     }
     #endif
     return ti;
   }
   //
   // Do not support shifted oops in info for GC
   //
   // else if( t1->base() == Type::InstPtr ) {
   //
   //   const TypeInstPtr *o = t1->is_instptr();
   //   if( t1->singleton() )
   //     return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
   // }
   // else if( t1->base() == Type::KlassPtr ) {
   //   const TypeKlassPtr *o = t1->is_klassptr();
   //   if( t1->singleton() )
   //     return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
   // }
   return TypeInt::INT;
 }
 //=============================================================================
 //------------------------------Identity---------------------------------------
 Node *URShiftLNode::Identity( PhaseTransform *phase ) {
   const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
   return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
 }
 //------------------------------Ideal------------------------------------------
 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   const TypeInt *t2 = phase->type( in(2) )->isa_int();
   if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
   const int con = t2->get_con() & ( BitsPerLong - 1 ); // Shift count is always masked
   if ( con == 0 ) return NULL;  // let Identity() handle a 0 shift count
                               // note: mask computation below does not work for 0 shift count
   // We'll be wanting the right-shift amount as a mask of that many bits
   const jlong mask = (((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) -1);
   // Check for ((x << z) + Y) >>> z.  Replace with x + con>>>z
   // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
   // If Q is "X << z" the rounding is useless.  Look for patterns like
   // ((X<<Z) + Y) >>> Z  and replace with (X + Y>>>Z) & Z-mask.
   Node *add = in(1);
   if( add->Opcode() == Op_AddL ) {
     Node *lshl = add->in(1);
     if( lshl->Opcode() == Op_LShiftL &&
         phase->type(lshl->in(2)) == t2 ) {
       Node *y_z = phase->transform( new (phase->C, 3) URShiftLNode(add->in(2),in(2)) );
       Node *sum = phase->transform( new (phase->C, 3) AddLNode( lshl->in(1), y_z ) );
       return new (phase->C, 3) AndLNode( sum, phase->longcon(mask) );
     }
   }
   // Check for (x & mask) >>> z.  Replace with (x >>> z) & (mask >>> z)
   // This shortens the mask.  Also, if we are extracting a high byte and
   // storing it to a buffer, the mask will be removed completely.
   Node *andi = in(1);
   if( andi->Opcode() == Op_AndL ) {
     const TypeLong *t3 = phase->type( andi->in(2) )->isa_long();
     if( t3 && t3->is_con() ) { // Right input is a constant
       jlong mask2 = t3->get_con();
       mask2 >>= con;  // *signed* shift downward (high-order zeroes do not help)
       Node *newshr = phase->transform( new (phase->C, 3) URShiftLNode(andi->in(1), in(2)) );
       return new (phase->C, 3) AndLNode(newshr, phase->longcon(mask2));
     }
   }
   // Check for "(X << z ) >>> z" which simply zero-extends
   Node *shl = in(1);
   if( shl->Opcode() == Op_LShiftL &&
       phase->type(shl->in(2)) == t2 )
     return new (phase->C, 3) AndLNode( shl->in(1), phase->longcon(mask) );
   return NULL;
 }
 //------------------------------Value------------------------------------------
 // A URShiftINode shifts its input2 right by input1 amount.
 const Type *URShiftLNode::Value( PhaseTransform *phase ) const {
   // (This is a near clone of RShiftLNode::Value.)
   const Type *t1 = phase->type( in(1) );
   const Type *t2 = phase->type( in(2) );
   // Either input is TOP ==> the result is TOP
   if( t1 == Type::TOP ) return Type::TOP;
   if( t2 == Type::TOP ) return Type::TOP;
   // Left input is ZERO ==> the result is ZERO.
   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
   // Shift by zero does nothing
   if( t2 == TypeInt::ZERO ) return t1;
   // Either input is BOTTOM ==> the result is BOTTOM
   if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
     return TypeLong::LONG;
   if (t2 == TypeInt::INT)
     return TypeLong::LONG;
   const TypeLong *r1 = t1->is_long(); // Handy access
   const TypeInt  *r2 = t2->is_int (); // Handy access
   if (r2->is_con()) {
     uint shift = r2->get_con();
     shift &= BitsPerJavaLong - 1;  // semantics of Java shifts
     // Shift by a multiple of 64 does nothing:
     if (shift == 0)  return t1;
     // Calculate reasonably aggressive bounds for the result.
     jlong lo = (julong)r1->_lo >> (juint)shift;
     jlong hi = (julong)r1->_hi >> (juint)shift;
     if (r1->_hi >= 0 && r1->_lo < 0) {
       // If the type has both negative and positive values,
       // there are two separate sub-domains to worry about:
       // The positive half and the negative half.
       jlong neg_lo = lo;
       jlong neg_hi = (julong)-1 >> (juint)shift;
       jlong pos_lo = (julong) 0 >> (juint)shift;
       jlong pos_hi = hi;
       //lo = MIN2(neg_lo, pos_lo);  // == 0
       lo = neg_lo < pos_lo ? neg_lo : pos_lo;
       //hi = MAX2(neg_hi, pos_hi);  // == -1 >>> shift;
       hi = neg_hi > pos_hi ? neg_hi : pos_hi;
     }
     assert(lo <= hi, "must have valid bounds");
     const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
     #ifdef ASSERT
     // Make sure we get the sign-capture idiom correct.
     if (shift == BitsPerJavaLong - 1) {
       if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0");
       if (r1->_hi < 0)  assert(tl == TypeLong::ONE,  ">>>63 of - is +1");
     }
     #endif
     return tl;
   }
   return TypeLong::LONG;                // Give up
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/mulnode.cpp@bd441136a5ce (annotated)

src/share/vm/opto/mulnode.cpp