Mercurial > hg > truffle
diff src/share/vm/opto/mulnode.cpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | f3de1255b035 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/opto/mulnode.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,1310 @@ +/* + * 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 +}