truffle: src/share/vm/opto/mulnode.cpp comparison

comparison src/share/vm/opto/mulnode.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	f3de1255b035

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+:a61af66fc99e
+/*
+* Copyright 1997-2006 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();
+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 adding 2 double constants.
+return TypeD::make( t0->getd() * t1->getd() );
+}
+//=============================================================================
+//------------------------------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_LoadC &&
+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() ) {
+int shift_con = t12->get_con();
+int mask = max_juint >> shift_con;
+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_LoadC &&
+(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 *ldc = new (phase->C, 3) LoadCNode(load->in(MemNode::Control),
+load->in(MemNode::Memory),
+load->in(MemNode::Address),
+load->adr_type());
+ldc = phase->transform(ldc);
+return new (phase->C, 3) AndINode(ldc,phase->intcon(mask&0xFFFF));
+}
+// Masking sign bits off of a Byte?  Let the matcher use an unsigned load
+if( lop == Op_LoadB &&
+(!in(0) && load->in(0)) &&
+(mask == 0x000000FF) ) {
+// Associate this node with the LoadB, so the matcher can see them together.
+// If we don't do this, it is common for the LoadB to have one control
+// edge, and the store or call containing this AndI to have a different
+// control edge.  This will cause Label_Root to group the AndI with
+// the encoding store or call, so the matcher has no chance to match
+// this AndI together with the LoadB.  Setting the control edge here
+// prevents Label_Root from grouping the AndI with the store or call,
+// if it has a control edge that is inconsistent with the LoadB.
+set_req(0, load->in(0));
+return this;
+}
+// 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() ) {
+int shift_con = t12->get_con();
+jlong mask = max_julong >> shift_con;
+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 *rsh = in(1);
+uint rop = rsh->Opcode();
+// Masking off sign bits?  Dont make them!
+if( rop == Op_RShiftL ) {
+const TypeInt *t12 = phase->type(rsh->in(2))->isa_int();
+if( t12 && t12->is_con() ) { // Shift is by a constant
+int shift = t12->get_con();
+shift &= (BitsPerJavaInteger*2)-1;  // semantics of Java shifts
+const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaInteger*2 - 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(rsh->in(1),rsh->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)(BitsPerJavaInteger*2 - 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 &= (BitsPerJavaInteger*2)-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_LoadC )
+// 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)(BitsPerJavaInteger*2 - 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 &= (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.
+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 == (2*BitsPerJavaInteger)-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 > hg > truffle

comparison src/share/vm/opto/mulnode.cpp @ 0:a61af66fc99e jdk7-b24