Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "memory/allocation.inline.hpp"

 #include "opto/addnode.hpp"

 #include "opto/cfgnode.hpp"

 #include "opto/connode.hpp"

 #include "opto/machnode.hpp"

 #include "opto/mulnode.hpp"

 #include "opto/phaseX.hpp"

 #include "opto/subnode.hpp"

 // Portions of code courtesy of Clifford Click

 // Classic Add functionality.  This covers all the usual 'add' behaviors for

 // an algebraic ring.  Add-integer, add-float, add-double, and binary-or are

 // all inherited from this class.  The various identity values are supplied

 // by virtual functions.

 //=============================================================================

 //------------------------------hash-------------------------------------------

 // Hash function over AddNodes.  Needs to be commutative; i.e., I swap

 // (commute) inputs to AddNodes willy-nilly so the hash function must return

 // the same value in the presence of edge swapping.

 uint AddNode::hash() const {

   return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();

 }

 //------------------------------Identity---------------------------------------

 // If either input is a constant 0, return the other input.

 Node *AddNode::Identity( PhaseTransform *phase ) {

   const Type *zero = add_id();  // The additive identity

   if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);

   if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);

   return this;

 }

 //------------------------------commute----------------------------------------

 // Commute operands to move loads and constants to the right.

 static bool commute( Node *add, int con_left, int con_right ) {

   Node *in1 = add->in(1);

   Node *in2 = add->in(2);

   // Convert "1+x" into "x+1".

   // Right is a constant; leave it

   if( con_right ) return false;

   // Left is a constant; move it right.

   if( con_left ) {

     add->swap_edges(1, 2);

     return true;

   }

   // Convert "Load+x" into "x+Load".

   // Now check for loads

   if (in2->is_Load()) {

     if (!in1->is_Load()) {

       // already x+Load to return

       return false;

     }

     // both are loads, so fall through to sort inputs by idx

   } else if( in1->is_Load() ) {

     // Left is a Load and Right is not; move it right.

     add->swap_edges(1, 2);

     return true;

   }

   PhiNode *phi;

   // Check for tight loop increments: Loop-phi of Add of loop-phi

   if( in1->is_Phi() && (phi = in1->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add)

     return false;

   if( in2->is_Phi() && (phi = in2->as_Phi()) && !phi->is_copy() && phi->region()->is_Loop() && phi->in(2)==add){

     add->swap_edges(1, 2);

     return true;

   }

   // Otherwise, sort inputs (commutativity) to help value numbering.

   if( in1->_idx > in2->_idx ) {

     add->swap_edges(1, 2);

     return true;

   }

   return false;

 }

 //------------------------------Idealize---------------------------------------

 // If we get here, we assume we are associative!

 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   const Type *t1 = phase->type( in(1) );

   const Type *t2 = phase->type( in(2) );

   int con_left  = t1->singleton();

   int con_right = t2->singleton();

   // Check for commutative operation desired

   if( commute(this,con_left,con_right) ) return this;

   AddNode *progress = NULL;             // Progress flag

   // Convert "(x+1)+2" into "x+(1+2)".  If the right input is a

   // constant, and the left input is an add of a constant, flatten the

   // expression tree.

   Node *add1 = in(1);

   Node *add2 = in(2);

   int add1_op = add1->Opcode();

   int this_op = Opcode();

   if( con_right && t2 != Type::TOP && // Right input is a constant?

       add1_op == this_op ) { // Left input is an Add?

     // Type of left _in right input

     const Type *t12 = phase->type( add1->in(2) );

     if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?

       // Check for rare case of closed data cycle which can happen inside

       // unreachable loops. In these cases the computation is undefined.

 #ifdef ASSERT

       Node *add11    = add1->in(1);

       int   add11_op = add11->Opcode();

       if( (add1 == add1->in(1))

          || (add11_op == this_op && add11->in(1) == add1) ) {

         assert(false, "dead loop in AddNode::Ideal");

       }

 #endif

       // The Add of the flattened expression

       Node *x1 = add1->in(1);

       Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));

       PhaseIterGVN *igvn = phase->is_IterGVN();

       if( igvn ) {

         set_req_X(2,x2,igvn);

         set_req_X(1,x1,igvn);

       } else {

         set_req(2,x2);

         set_req(1,x1);

       }

       progress = this;            // Made progress

       add1 = in(1);

       add1_op = add1->Opcode();

     }

   }

   // Convert "(x+1)+y" into "(x+y)+1".  Push constants down the expression tree.

   if( add1_op == this_op && !con_right ) {

     Node *a12 = add1->in(2);

     const Type *t12 = phase->type( a12 );

     if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&

        !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {

       assert(add1->in(1) != this, "dead loop in AddNode::Ideal");

       add2 = add1->clone();

       add2->set_req(2, in(2));

       add2 = phase->transform(add2);

       set_req(1, add2);

       set_req(2, a12);

       progress = this;

       add2 = a12;

     }

   }

   // Convert "x+(y+1)" into "(x+y)+1".  Push constants down the expression tree.

   int add2_op = add2->Opcode();

   if( add2_op == this_op && !con_left ) {

     Node *a22 = add2->in(2);

     const Type *t22 = phase->type( a22 );

     if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&

        !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {

       assert(add2->in(1) != this, "dead loop in AddNode::Ideal");

       Node *addx = add2->clone();

       addx->set_req(1, in(1));

       addx->set_req(2, add2->in(1));

       addx = phase->transform(addx);

       set_req(1, addx);

       set_req(2, a22);

       progress = this;

     }

   }

   return progress;

 }

 //------------------------------Value-----------------------------------------

 // An add node sums it's two _in.  If one input is an RSD, we must mixin

 // the other input's symbols.

 const Type *AddNode::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;

   // Check for an addition involving the additive identity

   const Type *tadd = add_of_identity( t1, t2 );

   if( tadd ) return tadd;

   return add_ring(t1,t2);               // Local flavor of type addition

 }

 //------------------------------add_identity-----------------------------------

 // Check for addition of the identity

 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {

   const Type *zero = add_id();  // The additive identity

   if( t1->higher_equal( zero ) ) return t2;

   if( t2->higher_equal( zero ) ) return t1;

   return NULL;

 }

 //=============================================================================

 //------------------------------Idealize---------------------------------------

 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {

   Node* in1 = in(1);

   Node* in2 = in(2);

   int op1 = in1->Opcode();

   int op2 = in2->Opcode();

   // Fold (con1-x)+con2 into (con1+con2)-x

   if ( op1 == Op_AddI && op2 == Op_SubI ) {

     // Swap edges to try optimizations below

     in1 = in2;

     in2 = in(1);

     op1 = op2;

     op2 = in2->Opcode();

   }

   if( op1 == Op_SubI ) {

     const Type *t_sub1 = phase->type( in1->in(1) );

     const Type *t_2    = phase->type( in2        );

     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )

       return new (phase->C, 3) SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ),

                               in1->in(2) );

     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"

     if( op2 == Op_SubI ) {

       // Check for dead cycle: d = (a-b)+(c-d)

       assert( in1->in(2) != this && in2->in(2) != this,

               "dead loop in AddINode::Ideal" );

       Node *sub  = new (phase->C, 3) SubINode(NULL, NULL);

       sub->init_req(1, phase->transform(new (phase->C, 3) AddINode(in1->in(1), in2->in(1) ) ));

       sub->init_req(2, phase->transform(new (phase->C, 3) AddINode(in1->in(2), in2->in(2) ) ));

       return sub;

     }

     // Convert "(a-b)+(b+c)" into "(a+c)"

     if( op2 == Op_AddI && in1->in(2) == in2->in(1) ) {

       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");

       return new (phase->C, 3) AddINode(in1->in(1), in2->in(2));

     }

     // Convert "(a-b)+(c+b)" into "(a+c)"

     if( op2 == Op_AddI && in1->in(2) == in2->in(2) ) {

       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");

       return new (phase->C, 3) AddINode(in1->in(1), in2->in(1));

     }

     // Convert "(a-b)+(b-c)" into "(a-c)"

     if( op2 == Op_SubI && in1->in(2) == in2->in(1) ) {

       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");

       return new (phase->C, 3) SubINode(in1->in(1), in2->in(2));

     }

     // Convert "(a-b)+(c-a)" into "(c-b)"

     if( op2 == Op_SubI && in1->in(1) == in2->in(2) ) {

       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");

       return new (phase->C, 3) SubINode(in2->in(1), in1->in(2));

     }

   }

   // Convert "x+(0-y)" into "(x-y)"

   if( op2 == Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )

     return new (phase->C, 3) SubINode(in1, in2->in(2) );

   // Convert "(0-y)+x" into "(x-y)"

   if( op1 == Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )

     return new (phase->C, 3) SubINode( in2, in1->in(2) );

   // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.

   // Helps with array allocation math constant folding

   // See 4790063:

   // Unrestricted transformation is unsafe for some runtime values of 'x'

   // ( x ==  0, z == 1, y == -1 ) fails

   // ( x == -5, z == 1, y ==  1 ) fails

   // Transform works for small z and small negative y when the addition

   // (x + (y << z)) does not cross zero.

   // Implement support for negative y and (x >= -(y << z))

   // Have not observed cases where type information exists to support

   // positive y and (x <= -(y << z))

   if( op1 == Op_URShiftI && op2 == Op_ConI &&

       in1->in(2)->Opcode() == Op_ConI ) {

     jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter

     jint y = phase->type( in2 )->is_int()->get_con();

     if( z < 5 && -5 < y && y < 0 ) {

       const Type *t_in11 = phase->type(in1->in(1));

       if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {

         Node *a = phase->transform( new (phase->C, 3) AddINode( in1->in(1), phase->intcon(y<<z) ) );

         return new (phase->C, 3) URShiftINode( a, in1->in(2) );

       }

     }

   }

   return AddNode::Ideal(phase, can_reshape);

 }

 //------------------------------Identity---------------------------------------

 // Fold (x-y)+y  OR  y+(x-y)  into  x

 Node *AddINode::Identity( PhaseTransform *phase ) {

   if( in(1)->Opcode() == Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {

     return in(1)->in(1);

   }

   else if( in(2)->Opcode() == Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {

     return in(2)->in(1);

   }

   return AddNode::Identity(phase);

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.  Guaranteed never

 // to be passed a TOP or BOTTOM type, these are filtered out by

 // pre-check.

 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeInt *r0 = t0->is_int(); // Handy access

   const TypeInt *r1 = t1->is_int();

   int lo = r0->_lo + r1->_lo;

   int hi = r0->_hi + r1->_hi;

   if( !(r0->is_con() && r1->is_con()) ) {

     // Not both constants, compute approximate result

     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {

       lo = min_jint; hi = max_jint; // Underflow on the low side

     }

     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {

       lo = min_jint; hi = max_jint; // Overflow on the high side

     }

     if( lo > hi ) {               // Handle overflow

       lo = min_jint; hi = max_jint;

     }

   } else {

     // both constants, compute precise result using 'lo' and 'hi'

     // Semantics define overflow and underflow for integer addition

     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0

   }

   return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );

 }

 //=============================================================================

 //------------------------------Idealize---------------------------------------

 Node *AddLNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   Node* in1 = in(1);

   Node* in2 = in(2);

   int op1 = in1->Opcode();

   int op2 = in2->Opcode();

   // Fold (con1-x)+con2 into (con1+con2)-x

   if ( op1 == Op_AddL && op2 == Op_SubL ) {

     // Swap edges to try optimizations below

     in1 = in2;

     in2 = in(1);

     op1 = op2;

     op2 = in2->Opcode();

   }

   // Fold (con1-x)+con2 into (con1+con2)-x

   if( op1 == Op_SubL ) {

     const Type *t_sub1 = phase->type( in1->in(1) );

     const Type *t_2    = phase->type( in2        );

     if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )

       return new (phase->C, 3) SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ),

                               in1->in(2) );

     // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"

     if( op2 == Op_SubL ) {

       // Check for dead cycle: d = (a-b)+(c-d)

       assert( in1->in(2) != this && in2->in(2) != this,

               "dead loop in AddLNode::Ideal" );

       Node *sub  = new (phase->C, 3) SubLNode(NULL, NULL);

       sub->init_req(1, phase->transform(new (phase->C, 3) AddLNode(in1->in(1), in2->in(1) ) ));

       sub->init_req(2, phase->transform(new (phase->C, 3) AddLNode(in1->in(2), in2->in(2) ) ));

       return sub;

     }

     // Convert "(a-b)+(b+c)" into "(a+c)"

     if( op2 == Op_AddL && in1->in(2) == in2->in(1) ) {

       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");

       return new (phase->C, 3) AddLNode(in1->in(1), in2->in(2));

     }

     // Convert "(a-b)+(c+b)" into "(a+c)"

     if( op2 == Op_AddL && in1->in(2) == in2->in(2) ) {

       assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");

       return new (phase->C, 3) AddLNode(in1->in(1), in2->in(1));

     }

     // Convert "(a-b)+(b-c)" into "(a-c)"

     if( op2 == Op_SubL && in1->in(2) == in2->in(1) ) {

       assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");

       return new (phase->C, 3) SubLNode(in1->in(1), in2->in(2));

     }

     // Convert "(a-b)+(c-a)" into "(c-b)"

     if( op2 == Op_SubL && in1->in(1) == in1->in(2) ) {

       assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");

       return new (phase->C, 3) SubLNode(in2->in(1), in1->in(2));

     }

   }

   // Convert "x+(0-y)" into "(x-y)"

   if( op2 == Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )

     return new (phase->C, 3) SubLNode( in1, in2->in(2) );

   // Convert "(0-y)+x" into "(x-y)"

   if( op1 == Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )

     return new (phase->C, 3) SubLNode( in2, in1->in(2) );

   // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"

   // into "(X<<1)+Y" and let shift-folding happen.

   if( op2 == Op_AddL &&

       in2->in(1) == in1 &&

       op1 != Op_ConL &&

       0 ) {

     Node *shift = phase->transform(new (phase->C, 3) LShiftLNode(in1,phase->intcon(1)));

     return new (phase->C, 3) AddLNode(shift,in2->in(2));

   }

   return AddNode::Ideal(phase, can_reshape);

 }

 //------------------------------Identity---------------------------------------

 // Fold (x-y)+y  OR  y+(x-y)  into  x

 Node *AddLNode::Identity( PhaseTransform *phase ) {

   if( in(1)->Opcode() == Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {

     return in(1)->in(1);

   }

   else if( in(2)->Opcode() == Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {

     return in(2)->in(1);

   }

   return AddNode::Identity(phase);

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.  Guaranteed never

 // to be passed a TOP or BOTTOM type, these are filtered out by

 // pre-check.

 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeLong *r0 = t0->is_long(); // Handy access

   const TypeLong *r1 = t1->is_long();

   jlong lo = r0->_lo + r1->_lo;

   jlong hi = r0->_hi + r1->_hi;

   if( !(r0->is_con() && r1->is_con()) ) {

     // Not both constants, compute approximate result

     if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {

       lo =min_jlong; hi = max_jlong; // Underflow on the low side

     }

     if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {

       lo = min_jlong; hi = max_jlong; // Overflow on the high side

     }

     if( lo > hi ) {               // Handle overflow

       lo = min_jlong; hi = max_jlong;

     }

   } else {

     // both constants, compute precise result using 'lo' and 'hi'

     // Semantics define overflow and underflow for integer addition

     // as expected.  In particular: 0x80000000 + 0x80000000 --> 0x0

   }

   return TypeLong::make( lo, hi, MAX2(r0->_widen,r1->_widen) );

 }

 //=============================================================================

 //------------------------------add_of_identity--------------------------------

 // Check for addition of the identity

 const Type *AddFNode::add_of_identity( const Type *t1, const Type *t2 ) const {

   // x ADD 0  should return x unless 'x' is a -zero

   //

   // const Type *zero = add_id();     // The additive identity

   // jfloat f1 = t1->getf();

   // jfloat f2 = t2->getf();

   //

   // if( t1->higher_equal( zero ) ) return t2;

   // if( t2->higher_equal( zero ) ) return t1;

   return NULL;

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.

 // 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 *AddFNode::add_ring( const Type *t0, const Type *t1 ) const {

   // We must be adding 2 float constants.

   return TypeF::make( t0->getf() + t1->getf() );

 }

 //------------------------------Ideal------------------------------------------

 Node *AddFNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {

     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms

   }

   // Floating point additions are not associative because of boundary conditions (infinity)

   return commute(this,

                  phase->type( in(1) )->singleton(),

                  phase->type( in(2) )->singleton() ) ? this : NULL;

 }

 //=============================================================================

 //------------------------------add_of_identity--------------------------------

 // Check for addition of the identity

 const Type *AddDNode::add_of_identity( const Type *t1, const Type *t2 ) const {

   // x ADD 0  should return x unless 'x' is a -zero

   //

   // const Type *zero = add_id();     // The additive identity

   // jfloat f1 = t1->getf();

   // jfloat f2 = t2->getf();

   //

   // if( t1->higher_equal( zero ) ) return t2;

   // if( t2->higher_equal( zero ) ) return t1;

   return NULL;

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.

 // 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 *AddDNode::add_ring( const Type *t0, const Type *t1 ) const {

   // We must be adding 2 double constants.

   return TypeD::make( t0->getd() + t1->getd() );

 }

 //------------------------------Ideal------------------------------------------

 Node *AddDNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   if( IdealizedNumerics && !phase->C->method()->is_strict() ) {

     return AddNode::Ideal(phase, can_reshape); // commutative and associative transforms

   }

   // Floating point additions are not associative because of boundary conditions (infinity)

   return commute(this,

                  phase->type( in(1) )->singleton(),

                  phase->type( in(2) )->singleton() ) ? this : NULL;

 }

 //=============================================================================

 //------------------------------Identity---------------------------------------

 // If one input is a constant 0, return the other input.

 Node *AddPNode::Identity( PhaseTransform *phase ) {

   return ( phase->type( in(Offset) )->higher_equal( TypeX_ZERO ) ) ? in(Address) : this;

 }

 //------------------------------Idealize---------------------------------------

 Node *AddPNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   // Bail out if dead inputs

   if( phase->type( in(Address) ) == Type::TOP ) return NULL;

   // If the left input is an add of a constant, flatten the expression tree.

   const Node *n = in(Address);

   if (n->is_AddP() && n->in(Base) == in(Base)) {

     const AddPNode *addp = n->as_AddP(); // Left input is an AddP

     assert( !addp->in(Address)->is_AddP() ||

              addp->in(Address)->as_AddP() != addp,

             "dead loop in AddPNode::Ideal" );

     // Type of left input's right input

     const Type *t = phase->type( addp->in(Offset) );

     if( t == Type::TOP ) return NULL;

     const TypeX *t12 = t->is_intptr_t();

     if( t12->is_con() ) {       // Left input is an add of a constant?

       // If the right input is a constant, combine constants

       const Type *temp_t2 = phase->type( in(Offset) );

       if( temp_t2 == Type::TOP ) return NULL;

       const TypeX *t2 = temp_t2->is_intptr_t();

       Node* address;

       Node* offset;

       if( t2->is_con() ) {

         // The Add of the flattened expression

         address = addp->in(Address);

         offset  = phase->MakeConX(t2->get_con() + t12->get_con());

       } else {

         // Else move the constant to the right.  ((A+con)+B) into ((A+B)+con)

         address = phase->transform(new (phase->C, 4) AddPNode(in(Base),addp->in(Address),in(Offset)));

         offset  = addp->in(Offset);

       }

       PhaseIterGVN *igvn = phase->is_IterGVN();

       if( igvn ) {

         set_req_X(Address,address,igvn);

         set_req_X(Offset,offset,igvn);

       } else {

         set_req(Address,address);

         set_req(Offset,offset);

       }

       return this;

     }

   }

   // Raw pointers?

   if( in(Base)->bottom_type() == Type::TOP ) {

     // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.

     if (phase->type(in(Address)) == TypePtr::NULL_PTR) {

       Node* offset = in(Offset);

       return new (phase->C, 2) CastX2PNode(offset);

     }

   }

   // If the right is an add of a constant, push the offset down.

   // Convert: (ptr + (offset+con)) into (ptr+offset)+con.

   // The idea is to merge array_base+scaled_index groups together,

   // and only have different constant offsets from the same base.

   const Node *add = in(Offset);

   if( add->Opcode() == Op_AddX && add->in(1) != add ) {

     const Type *t22 = phase->type( add->in(2) );

     if( t22->singleton() && (t22 != Type::TOP) ) {  // Right input is an add of a constant?

       set_req(Address, phase->transform(new (phase->C, 4) AddPNode(in(Base),in(Address),add->in(1))));

       set_req(Offset, add->in(2));

       return this;              // Made progress

     }

   }

   return NULL;                  // No progress

 }

 //------------------------------bottom_type------------------------------------

 // Bottom-type is the pointer-type with unknown offset.

 const Type *AddPNode::bottom_type() const {

   if (in(Address) == NULL)  return TypePtr::BOTTOM;

   const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();

   if( !tp ) return Type::TOP;   // TOP input means TOP output

   assert( in(Offset)->Opcode() != Op_ConP, "" );

   const Type *t = in(Offset)->bottom_type();

   if( t == Type::TOP )

     return tp->add_offset(Type::OffsetTop);

   const TypeX *tx = t->is_intptr_t();

   intptr_t txoffset = Type::OffsetBot;

   if (tx->is_con()) {   // Left input is an add of a constant?

     txoffset = tx->get_con();

   }

   return tp->add_offset(txoffset);

 }

 //------------------------------Value------------------------------------------

 const Type *AddPNode::Value( PhaseTransform *phase ) const {

   // Either input is TOP ==> the result is TOP

   const Type *t1 = phase->type( in(Address) );

   const Type *t2 = phase->type( in(Offset) );

   if( t1 == Type::TOP ) return Type::TOP;

   if( t2 == Type::TOP ) return Type::TOP;

   // Left input is a pointer

   const TypePtr *p1 = t1->isa_ptr();

   // Right input is an int

   const TypeX *p2 = t2->is_intptr_t();

   // Add 'em

   intptr_t p2offset = Type::OffsetBot;

   if (p2->is_con()) {   // Left input is an add of a constant?

     p2offset = p2->get_con();

   }

   return p1->add_offset(p2offset);

 }

 //------------------------Ideal_base_and_offset--------------------------------

 // Split an oop pointer into a base and offset.

 // (The offset might be Type::OffsetBot in the case of an array.)

 // Return the base, or NULL if failure.

 Node* AddPNode::Ideal_base_and_offset(Node* ptr, PhaseTransform* phase,

                                       // second return value:

                                       intptr_t& offset) {

   if (ptr->is_AddP()) {

     Node* base = ptr->in(AddPNode::Base);

     Node* addr = ptr->in(AddPNode::Address);

     Node* offs = ptr->in(AddPNode::Offset);

     if (base == addr || base->is_top()) {

       offset = phase->find_intptr_t_con(offs, Type::OffsetBot);

       if (offset != Type::OffsetBot) {

         return addr;

       }

     }

   }

   offset = Type::OffsetBot;

   return NULL;

 }

 //------------------------------unpack_offsets----------------------------------

 // Collect the AddP offset values into the elements array, giving up

 // if there are more than length.

 int AddPNode::unpack_offsets(Node* elements[], int length) {

   int count = 0;

   Node* addr = this;

   Node* base = addr->in(AddPNode::Base);

   while (addr->is_AddP()) {

     if (addr->in(AddPNode::Base) != base) {

       // give up

       return -1;

     }

     elements[count++] = addr->in(AddPNode::Offset);

     if (count == length) {

       // give up

       return -1;

     }

     addr = addr->in(AddPNode::Address);

   }

   if (addr != base) {

     return -1;

   }

   return count;

 }

 //------------------------------match_edge-------------------------------------

 // Do we Match on this edge index or not?  Do not match base pointer edge

 uint AddPNode::match_edge(uint idx) const {

   return idx > Base;

 }

 //=============================================================================

 //------------------------------Identity---------------------------------------

 Node *OrINode::Identity( PhaseTransform *phase ) {

   // x | x => x

   if (phase->eqv(in(1), in(2))) {

     return in(1);

   }

   return AddNode::Identity(phase);

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For

 // the logical operations the ring's ADD is really a logical OR 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 *OrINode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeInt *r0 = t0->is_int(); // Handy access

   const TypeInt *r1 = t1->is_int();

   // If both args are bool, can figure out better types

   if ( r0 == TypeInt::BOOL ) {

     if ( r1 == TypeInt::ONE) {

       return TypeInt::ONE;

     } else if ( r1 == TypeInt::BOOL ) {

       return TypeInt::BOOL;

     }

   } else if ( r0 == TypeInt::ONE ) {

     if ( r1 == TypeInt::BOOL ) {

       return TypeInt::ONE;

     }

   }

   // If either input is not a constant, just return all integers.

   if( !r0->is_con() || !r1->is_con() )

     return TypeInt::INT;        // Any integer, but still no symbols.

   // Otherwise just OR them bits.

   return TypeInt::make( r0->get_con() | r1->get_con() );

 }

 //=============================================================================

 //------------------------------Identity---------------------------------------

 Node *OrLNode::Identity( PhaseTransform *phase ) {

   // x | x => x

   if (phase->eqv(in(1), in(2))) {

     return in(1);

   }

   return AddNode::Identity(phase);

 }

 //------------------------------add_ring---------------------------------------

 const Type *OrLNode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeLong *r0 = t0->is_long(); // Handy access

   const TypeLong *r1 = t1->is_long();

   // If either input is not a constant, just return all integers.

   if( !r0->is_con() || !r1->is_con() )

     return TypeLong::LONG;      // Any integer, but still no symbols.

   // Otherwise just OR them bits.

   return TypeLong::make( r0->get_con() | r1->get_con() );

 }

 //=============================================================================

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs IN THE CURRENT RING.  For

 // the logical operations the ring's ADD is really a logical OR 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 *XorINode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeInt *r0 = t0->is_int(); // Handy access

   const TypeInt *r1 = t1->is_int();

   // Complementing a boolean?

   if( r0 == TypeInt::BOOL && ( r1 == TypeInt::ONE

                                || r1 == TypeInt::BOOL))

     return TypeInt::BOOL;

   if( !r0->is_con() || !r1->is_con() ) // Not constants

     return TypeInt::INT;        // Any integer, but still no symbols.

   // Otherwise just XOR them bits.

   return TypeInt::make( r0->get_con() ^ r1->get_con() );

 }

 //=============================================================================

 //------------------------------add_ring---------------------------------------

 const Type *XorLNode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeLong *r0 = t0->is_long(); // Handy access

   const TypeLong *r1 = t1->is_long();

   // If either input is not a constant, just return all integers.

   if( !r0->is_con() || !r1->is_con() )

     return TypeLong::LONG;      // Any integer, but still no symbols.

   // Otherwise just OR them bits.

   return TypeLong::make( r0->get_con() ^ r1->get_con() );

 }

 //=============================================================================

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.

 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeInt *r0 = t0->is_int(); // Handy access

   const TypeInt *r1 = t1->is_int();

   // Otherwise just MAX them bits.

   return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );

 }

 //=============================================================================

 //------------------------------Idealize---------------------------------------

 // MINs show up in range-check loop limit calculations.  Look for

 // "MIN2(x+c0,MIN2(y,x+c1))".  Pick the smaller constant: "MIN2(x+c0,y)"

 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {

   Node *progress = NULL;

   // Force a right-spline graph

   Node *l = in(1);

   Node *r = in(2);

   // Transform  MinI1( MinI2(a,b), c)  into  MinI1( a, MinI2(b,c) )

   // to force a right-spline graph for the rest of MinINode::Ideal().

   if( l->Opcode() == Op_MinI ) {

     assert( l != l->in(1), "dead loop in MinINode::Ideal" );

     r = phase->transform(new (phase->C, 3) MinINode(l->in(2),r));

     l = l->in(1);

     set_req(1, l);

     set_req(2, r);

     return this;

   }

   // Get left input & constant

   Node *x = l;

   int x_off = 0;

   if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant

       x->in(2)->is_Con() ) {

     const Type *t = x->in(2)->bottom_type();

     if( t == Type::TOP ) return NULL;  // No progress

     x_off = t->is_int()->get_con();

     x = x->in(1);

   }

   // Scan a right-spline-tree for MINs

   Node *y = r;

   int y_off = 0;

   // Check final part of MIN tree

   if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant

       y->in(2)->is_Con() ) {

     const Type *t = y->in(2)->bottom_type();

     if( t == Type::TOP ) return NULL;  // No progress

     y_off = t->is_int()->get_con();

     y = y->in(1);

   }

   if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {

     swap_edges(1, 2);

     return this;

   }

   if( r->Opcode() == Op_MinI ) {

     assert( r != r->in(2), "dead loop in MinINode::Ideal" );

     y = r->in(1);

     // Check final part of MIN tree

     if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant

         y->in(2)->is_Con() ) {

       const Type *t = y->in(2)->bottom_type();

       if( t == Type::TOP ) return NULL;  // No progress

       y_off = t->is_int()->get_con();

       y = y->in(1);

     }

     if( x->_idx > y->_idx )

       return new (phase->C, 3) MinINode(r->in(1),phase->transform(new (phase->C, 3) MinINode(l,r->in(2))));

     // See if covers: MIN2(x+c0,MIN2(y+c1,z))

     if( !phase->eqv(x,y) ) return NULL;

     // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into

     // MIN2(x+c0 or x+c1 which less, z).

     return new (phase->C, 3) MinINode(phase->transform(new (phase->C, 3) AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));

   } else {

     // See if covers: MIN2(x+c0,y+c1)

     if( !phase->eqv(x,y) ) return NULL;

     // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.

     return new (phase->C, 3) AddINode(x,phase->intcon(MIN2(x_off,y_off)));

   }

 }

 //------------------------------add_ring---------------------------------------

 // Supplied function returns the sum of the inputs.

 const Type *MinINode::add_ring( const Type *t0, const Type *t1 ) const {

   const TypeInt *r0 = t0->is_int(); // Handy access

   const TypeInt *r1 = t1->is_int();

   // Otherwise just MIN them bits.

   return TypeInt::make( MIN2(r0->_lo,r1->_lo), MIN2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );

 }