graal-compiler: src/share/vm/opto/memnode.cpp comparison

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

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	ff5961f4c095

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--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 1997-2007 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
+// Optimization - Graph Style
+#include "incls/_precompiled.incl"
+#include "incls/_memnode.cpp.incl"
+//=============================================================================
+uint MemNode::size_of() const { return sizeof(*this); }
+const TypePtr *MemNode::adr_type() const {
+Node* adr = in(Address);
+const TypePtr* cross_check = NULL;
+DEBUG_ONLY(cross_check = _adr_type);
+return calculate_adr_type(adr->bottom_type(), cross_check);
+}
+#ifndef PRODUCT
+void MemNode::dump_spec(outputStream *st) const {
+if (in(Address) == NULL)  return; // node is dead
+#ifndef ASSERT
+// fake the missing field
+const TypePtr* _adr_type = NULL;
+if (in(Address) != NULL)
+_adr_type = in(Address)->bottom_type()->isa_ptr();
+#endif
+dump_adr_type(this, _adr_type, st);
+Compile* C = Compile::current();
+if( C->alias_type(_adr_type)->is_volatile() )
+st->print(" Volatile!");
+}
+void MemNode::dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st) {
+st->print(" @");
+if (adr_type == NULL) {
+st->print("NULL");
+} else {
+adr_type->dump_on(st);
+Compile* C = Compile::current();
+Compile::AliasType* atp = NULL;
+if (C->have_alias_type(adr_type))  atp = C->alias_type(adr_type);
+if (atp == NULL)
+st->print(", idx=?\?;");
+else if (atp->index() == Compile::AliasIdxBot)
+st->print(", idx=Bot;");
+else if (atp->index() == Compile::AliasIdxTop)
+st->print(", idx=Top;");
+else if (atp->index() == Compile::AliasIdxRaw)
+st->print(", idx=Raw;");
+else {
+ciField* field = atp->field();
+if (field) {
+st->print(", name=");
+field->print_name_on(st);
+}
+st->print(", idx=%d;", atp->index());
+}
+}
+}
+extern void print_alias_types();
+#endif
+//--------------------------Ideal_common---------------------------------------
+// Look for degenerate control and memory inputs.  Bypass MergeMem inputs.
+// Unhook non-raw memories from complete (macro-expanded) initializations.
+Node *MemNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
+// If our control input is a dead region, kill all below the region
+Node *ctl = in(MemNode::Control);
+if (ctl && remove_dead_region(phase, can_reshape))
+return this;
+// Ignore if memory is dead, or self-loop
+Node *mem = in(MemNode::Memory);
+if( phase->type( mem ) == Type::TOP ) return NodeSentinel; // caller will return NULL
+assert( mem != this, "dead loop in MemNode::Ideal" );
+Node *address = in(MemNode::Address);
+const Type *t_adr = phase->type( address );
+if( t_adr == Type::TOP )              return NodeSentinel; // caller will return NULL
+// Avoid independent memory operations
+Node* old_mem = mem;
+if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
+InitializeNode* init = mem->in(0)->as_Initialize();
+if (init->is_complete()) {  // i.e., after macro expansion
+const TypePtr* tp = t_adr->is_ptr();
+uint alias_idx = phase->C->get_alias_index(tp);
+// Free this slice from the init.  It was hooked, temporarily,
+// by GraphKit::set_output_for_allocation.
+if (alias_idx > Compile::AliasIdxRaw) {
+mem = init->memory(alias_idx);
+// ...but not with the raw-pointer slice.
+}
+}
+}
+if (mem->is_MergeMem()) {
+MergeMemNode* mmem = mem->as_MergeMem();
+const TypePtr *tp = t_adr->is_ptr();
+uint alias_idx = phase->C->get_alias_index(tp);
+#ifdef ASSERT
+{
+// Check that current type is consistent with the alias index used during graph construction
+assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx");
+const TypePtr *adr_t =  adr_type();
+bool consistent =  adr_t == NULL || adr_t->empty() || phase->C->must_alias(adr_t, alias_idx );
+// Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
+if( !consistent && adr_t != NULL && !adr_t->empty() &&
+tp->isa_aryptr() &&    tp->offset() == Type::OffsetBot &&
+adr_t->isa_aryptr() && adr_t->offset() != Type::OffsetBot &&
+( adr_t->offset() == arrayOopDesc::length_offset_in_bytes() ||
+adr_t->offset() == oopDesc::klass_offset_in_bytes() ||
+adr_t->offset() == oopDesc::mark_offset_in_bytes() ) ) {
+// don't assert if it is dead code.
+consistent = true;
+}
+if( !consistent ) {
+tty->print("alias_idx==%d, adr_type()==", alias_idx); if( adr_t == NULL ) { tty->print("NULL"); } else { adr_t->dump(); }
+tty->cr();
+print_alias_types();
+assert(consistent, "adr_type must match alias idx");
+}
+}
+#endif
+// TypeInstPtr::NOTNULL+any is an OOP with unknown offset - generally
+// means an array I have not precisely typed yet.  Do not do any
+// alias stuff with it any time soon.
+const TypeInstPtr *tinst = tp->isa_instptr();
+if( tp->base() != Type::AnyPtr &&
+!(tinst &&
+tinst->klass()->is_java_lang_Object() &&
+tinst->offset() == Type::OffsetBot) ) {
+// compress paths and change unreachable cycles to TOP
+// If not, we can update the input infinitely along a MergeMem cycle
+// Equivalent code in PhiNode::Ideal
+Node* m  = phase->transform(mmem);
+// If tranformed to a MergeMem, get the desired slice
+// Otherwise the returned node represents memory for every slice
+mem = (m->is_MergeMem())? m->as_MergeMem()->memory_at(alias_idx) : m;
+// Update input if it is progress over what we have now
+}
+}
+if (mem != old_mem) {
+set_req(MemNode::Memory, mem);
+return this;
+}
+// let the subclass continue analyzing...
+return NULL;
+}
+// Helper function for proving some simple control dominations.
+// Attempt to prove that control input 'dom' dominates (or equals) 'sub'.
+// Already assumes that 'dom' is available at 'sub', and that 'sub'
+// is not a constant (dominated by the method's StartNode).
+// Used by MemNode::find_previous_store to prove that the
+// control input of a memory operation predates (dominates)
+// an allocation it wants to look past.
+bool MemNode::detect_dominating_control(Node* dom, Node* sub) {
+if (dom == NULL)      return false;
+if (dom->is_Proj())   dom = dom->in(0);
+if (dom->is_Start())  return true; // anything inside the method
+if (dom->is_Root())   return true; // dom 'controls' a constant
+int cnt = 20;                      // detect cycle or too much effort
+while (sub != NULL) {              // walk 'sub' up the chain to 'dom'
+if (--cnt < 0)   return false;   // in a cycle or too complex
+if (sub == dom)  return true;
+if (sub->is_Start())  return false;
+if (sub->is_Root())   return false;
+Node* up = sub->in(0);
+if (sub == up && sub->is_Region()) {
+for (uint i = 1; i < sub->req(); i++) {
+Node* in = sub->in(i);
+if (in != NULL && !in->is_top() && in != sub) {
+up = in; break;            // take any path on the way up to 'dom'
+}
+}
+}
+if (sub == up)  return false;    // some kind of tight cycle
+sub = up;
+}
+return false;
+}
+//---------------------detect_ptr_independence---------------------------------
+// Used by MemNode::find_previous_store to prove that two base
+// pointers are never equal.
+// The pointers are accompanied by their associated allocations,
+// if any, which have been previously discovered by the caller.
+bool MemNode::detect_ptr_independence(Node* p1, AllocateNode* a1,
+Node* p2, AllocateNode* a2,
+PhaseTransform* phase) {
+// Attempt to prove that these two pointers cannot be aliased.
+// They may both manifestly be allocations, and they should differ.
+// Or, if they are not both allocations, they can be distinct constants.
+// Otherwise, one is an allocation and the other a pre-existing value.
+if (a1 == NULL && a2 == NULL) {           // neither an allocation
+return (p1 != p2) && p1->is_Con() && p2->is_Con();
+} else if (a1 != NULL && a2 != NULL) {    // both allocations
+return (a1 != a2);
+} else if (a1 != NULL) {                  // one allocation a1
+// (Note:  p2->is_Con implies p2->in(0)->is_Root, which dominates.)
+return detect_dominating_control(p2->in(0), a1->in(0));
+} else { //(a2 != NULL)                   // one allocation a2
+return detect_dominating_control(p1->in(0), a2->in(0));
+}
+return false;
+}
+// The logic for reordering loads and stores uses four steps:
+// (a) Walk carefully past stores and initializations which we
+//     can prove are independent of this load.
+// (b) Observe that the next memory state makes an exact match
+//     with self (load or store), and locate the relevant store.
+// (c) Ensure that, if we were to wire self directly to the store,
+//     the optimizer would fold it up somehow.
+// (d) Do the rewiring, and return, depending on some other part of
+//     the optimizer to fold up the load.
+// This routine handles steps (a) and (b).  Steps (c) and (d) are
+// specific to loads and stores, so they are handled by the callers.
+// (Currently, only LoadNode::Ideal has steps (c), (d).  More later.)
+//
+Node* MemNode::find_previous_store(PhaseTransform* phase) {
+Node*         ctrl   = in(MemNode::Control);
+Node*         adr    = in(MemNode::Address);
+intptr_t      offset = 0;
+Node*         base   = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+AllocateNode* alloc  = AllocateNode::Ideal_allocation(base, phase);
+if (offset == Type::OffsetBot)
+return NULL;            // cannot unalias unless there are precise offsets
+intptr_t size_in_bytes = memory_size();
+Node* mem = in(MemNode::Memory);   // start searching here...
+int cnt = 50;             // Cycle limiter
+for (;;) {                // While we can dance past unrelated stores...
+if (--cnt < 0)  break;  // Caught in cycle or a complicated dance?
+if (mem->is_Store()) {
+Node* st_adr = mem->in(MemNode::Address);
+intptr_t st_offset = 0;
+Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
+if (st_base == NULL)
+break;              // inscrutable pointer
+if (st_offset != offset && st_offset != Type::OffsetBot) {
+const int MAX_STORE = BytesPerLong;
+if (st_offset >= offset + size_in_bytes ||
+st_offset <= offset - MAX_STORE ||
+st_offset <= offset - mem->as_Store()->memory_size()) {
+// Success:  The offsets are provably independent.
+// (You may ask, why not just test st_offset != offset and be done?
+// The answer is that stores of different sizes can co-exist
+// in the same sequence of RawMem effects.  We sometimes initialize
+// a whole 'tile' of array elements with a single jint or jlong.)
+mem = mem->in(MemNode::Memory);
+continue;           // (a) advance through independent store memory
+}
+}
+if (st_base != base &&
+detect_ptr_independence(base, alloc,
+st_base,
+AllocateNode::Ideal_allocation(st_base, phase),
+phase)) {
+// Success:  The bases are provably independent.
+mem = mem->in(MemNode::Memory);
+continue;           // (a) advance through independent store memory
+}
+// (b) At this point, if the bases or offsets do not agree, we lose,
+// since we have not managed to prove 'this' and 'mem' independent.
+if (st_base == base && st_offset == offset) {
+return mem;         // let caller handle steps (c), (d)
+}
+} else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
+InitializeNode* st_init = mem->in(0)->as_Initialize();
+AllocateNode*  st_alloc = st_init->allocation();
+if (st_alloc == NULL)
+break;              // something degenerated
+bool known_identical = false;
+bool known_independent = false;
+if (alloc == st_alloc)
+known_identical = true;
+else if (alloc != NULL)
+known_independent = true;
+else if (ctrl != NULL &&
+detect_dominating_control(ctrl, st_alloc->in(0)))
+known_independent = true;
+if (known_independent) {
+// The bases are provably independent: Either they are
+// manifestly distinct allocations, or else the control
+// of this load dominates the store's allocation.
+int alias_idx = phase->C->get_alias_index(adr_type());
+if (alias_idx == Compile::AliasIdxRaw) {
+mem = st_alloc->in(TypeFunc::Memory);
+} else {
+mem = st_init->memory(alias_idx);
+}
+continue;           // (a) advance through independent store memory
+}
+// (b) at this point, if we are not looking at a store initializing
+// the same allocation we are loading from, we lose.
+if (known_identical) {
+// From caller, can_see_stored_value will consult find_captured_store.
+return mem;         // let caller handle steps (c), (d)
+}
+}
+// Unless there is an explicit 'continue', we must bail out here,
+// because 'mem' is an inscrutable memory state (e.g., a call).
+break;
+}
+return NULL;              // bail out
+}
+//----------------------calculate_adr_type-------------------------------------
+// Helper function.  Notices when the given type of address hits top or bottom.
+// Also, asserts a cross-check of the type against the expected address type.
+const TypePtr* MemNode::calculate_adr_type(const Type* t, const TypePtr* cross_check) {
+if (t == Type::TOP)  return NULL; // does not touch memory any more?
+#ifdef PRODUCT
+cross_check = NULL;
+#else
+if (!VerifyAliases || is_error_reported() || Node::in_dump())  cross_check = NULL;
+#endif
+const TypePtr* tp = t->isa_ptr();
+if (tp == NULL) {
+assert(cross_check == NULL || cross_check == TypePtr::BOTTOM, "expected memory type must be wide");
+return TypePtr::BOTTOM;           // touches lots of memory
+} else {
+#ifdef ASSERT
+// %%%% [phh] We don't check the alias index if cross_check is
+//            TypeRawPtr::BOTTOM.  Needs to be investigated.
+if (cross_check != NULL &&
+cross_check != TypePtr::BOTTOM &&
+cross_check != TypeRawPtr::BOTTOM) {
+// Recheck the alias index, to see if it has changed (due to a bug).
+Compile* C = Compile::current();
+assert(C->get_alias_index(cross_check) == C->get_alias_index(tp),
+"must stay in the original alias category");
+// The type of the address must be contained in the adr_type,
+// disregarding "null"-ness.
+// (We make an exception for TypeRawPtr::BOTTOM, which is a bit bucket.)
+const TypePtr* tp_notnull = tp->join(TypePtr::NOTNULL)->is_ptr();
+assert(cross_check->meet(tp_notnull) == cross_check,
+"real address must not escape from expected memory type");
+}
+#endif
+return tp;
+}
+}
+//------------------------adr_phi_is_loop_invariant----------------------------
+// A helper function for Ideal_DU_postCCP to check if a Phi in a counted
+// loop is loop invariant. Make a quick traversal of Phi and associated
+// CastPP nodes, looking to see if they are a closed group within the loop.
+bool MemNode::adr_phi_is_loop_invariant(Node* adr_phi, Node* cast) {
+// The idea is that the phi-nest must boil down to only CastPP nodes
+// with the same data. This implies that any path into the loop already
+// includes such a CastPP, and so the original cast, whatever its input,
+// must be covered by an equivalent cast, with an earlier control input.
+ResourceMark rm;
+// The loop entry input of the phi should be the unique dominating
+// node for every Phi/CastPP in the loop.
+Unique_Node_List closure;
+closure.push(adr_phi->in(LoopNode::EntryControl));
+// Add the phi node and the cast to the worklist.
+Unique_Node_List worklist;
+worklist.push(adr_phi);
+if( cast != NULL ){
+if( !cast->is_ConstraintCast() ) return false;
+worklist.push(cast);
+}
+// Begin recursive walk of phi nodes.
+while( worklist.size() ){
+// Take a node off the worklist
+Node *n = worklist.pop();
+if( !closure.member(n) ){
+// Add it to the closure.
+closure.push(n);
+// Make a sanity check to ensure we don't waste too much time here.
+if( closure.size() > 20) return false;
+// This node is OK if:
+//  - it is a cast of an identical value
+//  - or it is a phi node (then we add its inputs to the worklist)
+// Otherwise, the node is not OK, and we presume the cast is not invariant
+if( n->is_ConstraintCast() ){
+worklist.push(n->in(1));
+} else if( n->is_Phi() ) {
+for( uint i = 1; i < n->req(); i++ ) {
+worklist.push(n->in(i));
+}
+} else {
+return false;
+}
+}
+}
+// Quit when the worklist is empty, and we've found no offending nodes.
+return true;
+}
+//------------------------------Ideal_DU_postCCP-------------------------------
+// Find any cast-away of null-ness and keep its control.  Null cast-aways are
+// going away in this pass and we need to make this memory op depend on the
+// gating null check.
+// I tried to leave the CastPP's in.  This makes the graph more accurate in
+// some sense; we get to keep around the knowledge that an oop is not-null
+// after some test.  Alas, the CastPP's interfere with GVN (some values are
+// the regular oop, some are the CastPP of the oop, all merge at Phi's which
+// cannot collapse, etc).  This cost us 10% on SpecJVM, even when I removed
+// some of the more trivial cases in the optimizer.  Removing more useless
+// Phi's started allowing Loads to illegally float above null checks.  I gave
+// up on this approach.  CNC 10/20/2000
+Node *MemNode::Ideal_DU_postCCP( PhaseCCP *ccp ) {
+Node *ctr = in(MemNode::Control);
+Node *mem = in(MemNode::Memory);
+Node *adr = in(MemNode::Address);
+Node *skipped_cast = NULL;
+// Need a null check?  Regular static accesses do not because they are
+// from constant addresses.  Array ops are gated by the range check (which
+// always includes a NULL check).  Just check field ops.
+if( !ctr ) {
+// Scan upwards for the highest location we can place this memory op.
+while( true ) {
+switch( adr->Opcode() ) {
+case Op_AddP:             // No change to NULL-ness, so peek thru AddP's
+adr = adr->in(AddPNode::Base);
+continue;
+case Op_CastPP:
+// If the CastPP is useless, just peek on through it.
+if( ccp->type(adr) == ccp->type(adr->in(1)) ) {
+// Remember the cast that we've peeked though. If we peek
+// through more than one, then we end up remembering the highest
+// one, that is, if in a loop, the one closest to the top.
+skipped_cast = adr;
+adr = adr->in(1);
+continue;
+}
+// CastPP is going away in this pass!  We need this memory op to be
+// control-dependent on the test that is guarding the CastPP.
+ccp->hash_delete(this);
+set_req(MemNode::Control, adr->in(0));
+ccp->hash_insert(this);
+return this;
+case Op_Phi:
+// Attempt to float above a Phi to some dominating point.
+if (adr->in(0) != NULL && adr->in(0)->is_CountedLoop()) {
+// If we've already peeked through a Cast (which could have set the
+// control), we can't float above a Phi, because the skipped Cast
+// may not be loop invariant.
+if (adr_phi_is_loop_invariant(adr, skipped_cast)) {
+adr = adr->in(1);
+continue;
+}
+}
+// Intentional fallthrough!
+// No obvious dominating point.  The mem op is pinned below the Phi
+// by the Phi itself.  If the Phi goes away (no true value is merged)
+// then the mem op can float, but not indefinitely.  It must be pinned
+// behind the controls leading to the Phi.
+case Op_CheckCastPP:
+// These usually stick around to change address type, however a
+// useless one can be elided and we still need to pick up a control edge
+if (adr->in(0) == NULL) {
+// This CheckCastPP node has NO control and is likely useless. But we
+// need check further up the ancestor chain for a control input to keep
+// the node in place. 4959717.
+skipped_cast = adr;
+adr = adr->in(1);
+continue;
+}
+ccp->hash_delete(this);
+set_req(MemNode::Control, adr->in(0));
+ccp->hash_insert(this);
+return this;
+// List of "safe" opcodes; those that implicitly block the memory
+// op below any null check.
+case Op_CastX2P:          // no null checks on native pointers
+case Op_Parm:             // 'this' pointer is not null
+case Op_LoadP:            // Loading from within a klass
+case Op_LoadKlass:        // Loading from within a klass
+case Op_ConP:             // Loading from a klass
+case Op_CreateEx:         // Sucking up the guts of an exception oop
+case Op_Con:              // Reading from TLS
+case Op_CMoveP:           // CMoveP is pinned
+break;                  // No progress
+case Op_Proj:             // Direct call to an allocation routine
+case Op_SCMemProj:        // Memory state from store conditional ops
+#ifdef ASSERT
+{
+assert(adr->as_Proj()->_con == TypeFunc::Parms, "must be return value");
+const Node* call = adr->in(0);
+if (call->is_CallStaticJava()) {
+const CallStaticJavaNode* call_java = call->as_CallStaticJava();
+assert(call_java && call_java->method() == NULL, "must be runtime call");
+// We further presume that this is one of
+// new_instance_Java, new_array_Java, or
+// the like, but do not assert for this.
+} else if (call->is_Allocate()) {
+// similar case to new_instance_Java, etc.
+} else if (!call->is_CallLeaf()) {
+// Projections from fetch_oop (OSR) are allowed as well.
+ShouldNotReachHere();
+}
+}
+#endif
+break;
+default:
+ShouldNotReachHere();
+}
+break;
+}
+}
+return  NULL;               // No progress
+}
+//=============================================================================
+uint LoadNode::size_of() const { return sizeof(*this); }
+uint LoadNode::cmp( const Node &n ) const
+{ return !Type::cmp( _type, ((LoadNode&)n)._type ); }
+const Type *LoadNode::bottom_type() const { return _type; }
+uint LoadNode::ideal_reg() const {
+return Matcher::base2reg[_type->base()];
+}
+#ifndef PRODUCT
+void LoadNode::dump_spec(outputStream *st) const {
+MemNode::dump_spec(st);
+if( !Verbose && !WizardMode ) {
+// standard dump does this in Verbose and WizardMode
+st->print(" #"); _type->dump_on(st);
+}
+}
+#endif
+//----------------------------LoadNode::make-----------------------------------
+// Polymorphic factory method:
+LoadNode *LoadNode::make( Compile *C, Node *ctl, Node *mem, Node *adr, const TypePtr* adr_type, const Type *rt, BasicType bt ) {
+// sanity check the alias category against the created node type
+assert(!(adr_type->isa_oopptr() &&
+adr_type->offset() == oopDesc::klass_offset_in_bytes()),
+"use LoadKlassNode instead");
+assert(!(adr_type->isa_aryptr() &&
+adr_type->offset() == arrayOopDesc::length_offset_in_bytes()),
+"use LoadRangeNode instead");
+switch (bt) {
+case T_BOOLEAN:
+case T_BYTE:    return new (C, 3) LoadBNode(ctl, mem, adr, adr_type, rt->is_int()    );
+case T_INT:     return new (C, 3) LoadINode(ctl, mem, adr, adr_type, rt->is_int()    );
+case T_CHAR:    return new (C, 3) LoadCNode(ctl, mem, adr, adr_type, rt->is_int()    );
+case T_SHORT:   return new (C, 3) LoadSNode(ctl, mem, adr, adr_type, rt->is_int()    );
+case T_LONG:    return new (C, 3) LoadLNode(ctl, mem, adr, adr_type, rt->is_long()   );
+case T_FLOAT:   return new (C, 3) LoadFNode(ctl, mem, adr, adr_type, rt              );
+case T_DOUBLE:  return new (C, 3) LoadDNode(ctl, mem, adr, adr_type, rt              );
+case T_ADDRESS: return new (C, 3) LoadPNode(ctl, mem, adr, adr_type, rt->is_ptr()    );
+case T_OBJECT:  return new (C, 3) LoadPNode(ctl, mem, adr, adr_type, rt->is_oopptr());
+}
+ShouldNotReachHere();
+return (LoadNode*)NULL;
+}
+LoadLNode* LoadLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt) {
+bool require_atomic = true;
+return new (C, 3) LoadLNode(ctl, mem, adr, adr_type, rt->is_long(), require_atomic);
+}
+//------------------------------hash-------------------------------------------
+uint LoadNode::hash() const {
+// unroll addition of interesting fields
+return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address);
+}
+//---------------------------can_see_stored_value------------------------------
+// This routine exists to make sure this set of tests is done the same
+// everywhere.  We need to make a coordinated change: first LoadNode::Ideal
+// will change the graph shape in a way which makes memory alive twice at the
+// same time (uses the Oracle model of aliasing), then some
+// LoadXNode::Identity will fold things back to the equivalence-class model
+// of aliasing.
+Node* MemNode::can_see_stored_value(Node* st, PhaseTransform* phase) const {
+Node* ld_adr = in(MemNode::Address);
+// Loop around twice in the case Load -> Initialize -> Store.
+// (See PhaseIterGVN::add_users_to_worklist, which knows about this case.)
+for (int trip = 0; trip <= 1; trip++) {
+if (st->is_Store()) {
+Node* st_adr = st->in(MemNode::Address);
+if (!phase->eqv(st_adr, ld_adr)) {
+// Try harder before giving up...  Match raw and non-raw pointers.
+intptr_t st_off = 0;
+AllocateNode* alloc = AllocateNode::Ideal_allocation(st_adr, phase, st_off);
+if (alloc == NULL)       return NULL;
+intptr_t ld_off = 0;
+AllocateNode* allo2 = AllocateNode::Ideal_allocation(ld_adr, phase, ld_off);
+if (alloc != allo2)      return NULL;
+if (ld_off != st_off)    return NULL;
+// At this point we have proven something like this setup:
+//  A = Allocate(...)
+//  L = LoadQ(,  AddP(CastPP(, A.Parm),, #Off))
+//  S = StoreQ(, AddP(,        A.Parm  , #Off), V)
+// (Actually, we haven't yet proven the Q's are the same.)
+// In other words, we are loading from a casted version of
+// the same pointer-and-offset that we stored to.
+// Thus, we are able to replace L by V.
+}
+// Now prove that we have a LoadQ matched to a StoreQ, for some Q.
+if (store_Opcode() != st->Opcode())
+return NULL;
+return st->in(MemNode::ValueIn);
+}
+intptr_t offset = 0;  // scratch
+// A load from a freshly-created object always returns zero.
+// (This can happen after LoadNode::Ideal resets the load's memory input
+// to find_captured_store, which returned InitializeNode::zero_memory.)
+if (st->is_Proj() && st->in(0)->is_Allocate() &&
+st->in(0) == AllocateNode::Ideal_allocation(ld_adr, phase, offset) &&
+offset >= st->in(0)->as_Allocate()->minimum_header_size()) {
+// return a zero value for the load's basic type
+// (This is one of the few places where a generic PhaseTransform
+// can create new nodes.  Think of it as lazily manifesting
+// virtually pre-existing constants.)
+return phase->zerocon(memory_type());
+}
+// A load from an initialization barrier can match a captured store.
+if (st->is_Proj() && st->in(0)->is_Initialize()) {
+InitializeNode* init = st->in(0)->as_Initialize();
+AllocateNode* alloc = init->allocation();
+if (alloc != NULL &&
+alloc == AllocateNode::Ideal_allocation(ld_adr, phase, offset)) {
+// examine a captured store value
+st = init->find_captured_store(offset, memory_size(), phase);
+if (st != NULL)
+continue;             // take one more trip around
+}
+}
+break;
+}
+return NULL;
+}
+//------------------------------Identity---------------------------------------
+// Loads are identity if previous store is to same address
+Node *LoadNode::Identity( PhaseTransform *phase ) {
+// If the previous store-maker is the right kind of Store, and the store is
+// to the same address, then we are equal to the value stored.
+Node* mem = in(MemNode::Memory);
+Node* value = can_see_stored_value(mem, phase);
+if( value ) {
+// byte, short & char stores truncate naturally.
+// A load has to load the truncated value which requires
+// some sort of masking operation and that requires an
+// Ideal call instead of an Identity call.
+if (memory_size() < BytesPerInt) {
+// If the input to the store does not fit with the load's result type,
+// it must be truncated via an Ideal call.
+if (!phase->type(value)->higher_equal(phase->type(this)))
+return this;
+}
+// (This works even when value is a Con, but LoadNode::Value
+// usually runs first, producing the singleton type of the Con.)
+return value;
+}
+return this;
+}
+//------------------------------Ideal------------------------------------------
+// If the load is from Field memory and the pointer is non-null, we can
+// zero out the control input.
+// If the offset is constant and the base is an object allocation,
+// try to hook me up to the exact initializing store.
+Node *LoadNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+Node* p = MemNode::Ideal_common(phase, can_reshape);
+if (p)  return (p == NodeSentinel) ? NULL : p;
+Node* ctrl    = in(MemNode::Control);
+Node* address = in(MemNode::Address);
+// Skip up past a SafePoint control.  Cannot do this for Stores because
+// pointer stores & cardmarks must stay on the same side of a SafePoint.
+if( ctrl != NULL && ctrl->Opcode() == Op_SafePoint &&
+phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw ) {
+ctrl = ctrl->in(0);
+set_req(MemNode::Control,ctrl);
+}
+// Check for useless control edge in some common special cases
+if (in(MemNode::Control) != NULL) {
+intptr_t ignore = 0;
+Node*    base   = AddPNode::Ideal_base_and_offset(address, phase, ignore);
+if (base != NULL
+&& phase->type(base)->higher_equal(TypePtr::NOTNULL)
+&& detect_dominating_control(base->in(0), phase->C->start())) {
+// A method-invariant, non-null address (constant or 'this' argument).
+set_req(MemNode::Control, NULL);
+}
+}
+// Check for prior store with a different base or offset; make Load
+// independent.  Skip through any number of them.  Bail out if the stores
+// are in an endless dead cycle and report no progress.  This is a key
+// transform for Reflection.  However, if after skipping through the Stores
+// we can't then fold up against a prior store do NOT do the transform as
+// this amounts to using the 'Oracle' model of aliasing.  It leaves the same
+// array memory alive twice: once for the hoisted Load and again after the
+// bypassed Store.  This situation only works if EVERYBODY who does
+// anti-dependence work knows how to bypass.  I.e. we need all
+// anti-dependence checks to ask the same Oracle.  Right now, that Oracle is
+// the alias index stuff.  So instead, peek through Stores and IFF we can
+// fold up, do so.
+Node* prev_mem = find_previous_store(phase);
+// Steps (a), (b):  Walk past independent stores to find an exact match.
+if (prev_mem != NULL && prev_mem != in(MemNode::Memory)) {
+// (c) See if we can fold up on the spot, but don't fold up here.
+// Fold-up might require truncation (for LoadB/LoadS/LoadC) or
+// just return a prior value, which is done by Identity calls.
+if (can_see_stored_value(prev_mem, phase)) {
+// Make ready for step (d):
+set_req(MemNode::Memory, prev_mem);
+return this;
+}
+}
+return NULL;                  // No further progress
+}
+// Helper to recognize certain Klass fields which are invariant across
+// some group of array types (e.g., int[] or all T[] where T < Object).
+const Type*
+LoadNode::load_array_final_field(const TypeKlassPtr *tkls,
+ciKlass* klass) const {
+if (tkls->offset() == Klass::modifier_flags_offset_in_bytes() + (int)sizeof(oopDesc)) {
+// The field is Klass::_modifier_flags.  Return its (constant) value.
+// (Folds up the 2nd indirection in aClassConstant.getModifiers().)
+assert(this->Opcode() == Op_LoadI, "must load an int from _modifier_flags");
+return TypeInt::make(klass->modifier_flags());
+}
+if (tkls->offset() == Klass::access_flags_offset_in_bytes() + (int)sizeof(oopDesc)) {
+// The field is Klass::_access_flags.  Return its (constant) value.
+// (Folds up the 2nd indirection in Reflection.getClassAccessFlags(aClassConstant).)
+assert(this->Opcode() == Op_LoadI, "must load an int from _access_flags");
+return TypeInt::make(klass->access_flags());
+}
+if (tkls->offset() == Klass::layout_helper_offset_in_bytes() + (int)sizeof(oopDesc)) {
+// The field is Klass::_layout_helper.  Return its constant value if known.
+assert(this->Opcode() == Op_LoadI, "must load an int from _layout_helper");
+return TypeInt::make(klass->layout_helper());
+}
+// No match.
+return NULL;
+}
+//------------------------------Value-----------------------------------------
+const Type *LoadNode::Value( PhaseTransform *phase ) const {
+// Either input is TOP ==> the result is TOP
+Node* mem = in(MemNode::Memory);
+const Type *t1 = phase->type(mem);
+if (t1 == Type::TOP)  return Type::TOP;
+Node* adr = in(MemNode::Address);
+const TypePtr* tp = phase->type(adr)->isa_ptr();
+if (tp == NULL || tp->empty())  return Type::TOP;
+int off = tp->offset();
+assert(off != Type::OffsetTop, "case covered by TypePtr::empty");
+// Try to guess loaded type from pointer type
+if (tp->base() == Type::AryPtr) {
+const Type *t = tp->is_aryptr()->elem();
+// Don't do this for integer types. There is only potential profit if
+// the element type t is lower than _type; that is, for int types, if _type is
+// more restrictive than t.  This only happens here if one is short and the other
+// char (both 16 bits), and in those cases we've made an intentional decision
+// to use one kind of load over the other. See AndINode::Ideal and 4965907.
+// Also, do not try to narrow the type for a LoadKlass, regardless of offset.
+//
+// Yes, it is possible to encounter an expression like (LoadKlass p1:(AddP x x 8))
+// where the _gvn.type of the AddP is wider than 8.  This occurs when an earlier
+// copy p0 of (AddP x x 8) has been proven equal to p1, and the p0 has been
+// subsumed by p1.  If p1 is on the worklist but has not yet been re-transformed,
+// it is possible that p1 will have a type like Foo*[int+]:NotNull*+any.
+// In fact, that could have been the original type of p1, and p1 could have
+// had an original form like p1:(AddP x x (LShiftL quux 3)), where the
+// expression (LShiftL quux 3) independently optimized to the constant 8.
+if ((t->isa_int() == NULL) && (t->isa_long() == NULL)
+&& Opcode() != Op_LoadKlass) {
+// t might actually be lower than _type, if _type is a unique
+// concrete subclass of abstract class t.
+// Make sure the reference is not into the header, by comparing
+// the offset against the offset of the start of the array's data.
+// Different array types begin at slightly different offsets (12 vs. 16).
+// We choose T_BYTE as an example base type that is least restrictive
+// as to alignment, which will therefore produce the smallest
+// possible base offset.
+const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE);
+if ((uint)off >= (uint)min_base_off) {  // is the offset beyond the header?
+const Type* jt = t->join(_type);
+// In any case, do not allow the join, per se, to empty out the type.
+if (jt->empty() && !t->empty()) {
+// This can happen if a interface-typed array narrows to a class type.
+jt = _type;
+}
+return jt;
+}
+}
+} else if (tp->base() == Type::InstPtr) {
+assert( off != Type::OffsetBot ||
+// arrays can be cast to Objects
+tp->is_oopptr()->klass()->is_java_lang_Object() ||
+// unsafe field access may not have a constant offset
+phase->C->has_unsafe_access(),
+"Field accesses must be precise" );
+// For oop loads, we expect the _type to be precise
+} else if (tp->base() == Type::KlassPtr) {
+assert( off != Type::OffsetBot ||
+// arrays can be cast to Objects
+tp->is_klassptr()->klass()->is_java_lang_Object() ||
+// also allow array-loading from the primary supertype
+// array during subtype checks
+Opcode() == Op_LoadKlass,
+"Field accesses must be precise" );
+// For klass/static loads, we expect the _type to be precise
+}
+const TypeKlassPtr *tkls = tp->isa_klassptr();
+if (tkls != NULL && !StressReflectiveCode) {
+ciKlass* klass = tkls->klass();
+if (klass->is_loaded() && tkls->klass_is_exact()) {
+// We are loading a field from a Klass metaobject whose identity
+// is known at compile time (the type is "exact" or "precise").
+// Check for fields we know are maintained as constants by the VM.
+if (tkls->offset() == Klass::super_check_offset_offset_in_bytes() + (int)sizeof(oopDesc)) {
+// The field is Klass::_super_check_offset.  Return its (constant) value.
+// (Folds up type checking code.)
+assert(Opcode() == Op_LoadI, "must load an int from _super_check_offset");
+return TypeInt::make(klass->super_check_offset());
+}
+// Compute index into primary_supers array
+juint depth = (tkls->offset() - (Klass::primary_supers_offset_in_bytes() + (int)sizeof(oopDesc))) / sizeof(klassOop);
+// Check for overflowing; use unsigned compare to handle the negative case.
+if( depth < ciKlass::primary_super_limit() ) {
+// The field is an element of Klass::_primary_supers.  Return its (constant) value.
+// (Folds up type checking code.)
+assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
+ciKlass *ss = klass->super_of_depth(depth);
+return ss ? TypeKlassPtr::make(ss) : TypePtr::NULL_PTR;
+}
+const Type* aift = load_array_final_field(tkls, klass);
+if (aift != NULL)  return aift;
+if (tkls->offset() == in_bytes(arrayKlass::component_mirror_offset()) + (int)sizeof(oopDesc)
+&& klass->is_array_klass()) {
+// The field is arrayKlass::_component_mirror.  Return its (constant) value.
+// (Folds up aClassConstant.getComponentType, common in Arrays.copyOf.)
+assert(Opcode() == Op_LoadP, "must load an oop from _component_mirror");
+return TypeInstPtr::make(klass->as_array_klass()->component_mirror());
+}
+if (tkls->offset() == Klass::java_mirror_offset_in_bytes() + (int)sizeof(oopDesc)) {
+// The field is Klass::_java_mirror.  Return its (constant) value.
+// (Folds up the 2nd indirection in anObjConstant.getClass().)
+assert(Opcode() == Op_LoadP, "must load an oop from _java_mirror");
+return TypeInstPtr::make(klass->java_mirror());
+}
+}
+// We can still check if we are loading from the primary_supers array at a
+// shallow enough depth.  Even though the klass is not exact, entries less
+// than or equal to its super depth are correct.
+if (klass->is_loaded() ) {
+ciType *inner = klass->klass();
+while( inner->is_obj_array_klass() )
+inner = inner->as_obj_array_klass()->base_element_type();
+if( inner->is_instance_klass() &&
+!inner->as_instance_klass()->flags().is_interface() ) {
+// Compute index into primary_supers array
+juint depth = (tkls->offset() - (Klass::primary_supers_offset_in_bytes() + (int)sizeof(oopDesc))) / sizeof(klassOop);
+// Check for overflowing; use unsigned compare to handle the negative case.
+if( depth < ciKlass::primary_super_limit() &&
+depth <= klass->super_depth() ) { // allow self-depth checks to handle self-check case
+// The field is an element of Klass::_primary_supers.  Return its (constant) value.
+// (Folds up type checking code.)
+assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
+ciKlass *ss = klass->super_of_depth(depth);
+return ss ? TypeKlassPtr::make(ss) : TypePtr::NULL_PTR;
+}
+}
+}
+// If the type is enough to determine that the thing is not an array,
+// we can give the layout_helper a positive interval type.
+// This will help short-circuit some reflective code.
+if (tkls->offset() == Klass::layout_helper_offset_in_bytes() + (int)sizeof(oopDesc)
+&& !klass->is_array_klass() // not directly typed as an array
+&& !klass->is_interface()  // specifically not Serializable & Cloneable
+&& !klass->is_java_lang_Object()   // not the supertype of all T[]
+) {
+// Note:  When interfaces are reliable, we can narrow the interface
+// test to (klass != Serializable && klass != Cloneable).
+assert(Opcode() == Op_LoadI, "must load an int from _layout_helper");
+jint min_size = Klass::instance_layout_helper(oopDesc::header_size(), false);
+// The key property of this type is that it folds up tests
+// for array-ness, since it proves that the layout_helper is positive.
+// Thus, a generic value like the basic object layout helper works fine.
+return TypeInt::make(min_size, max_jint, Type::WidenMin);
+}
+}
+// If we are loading from a freshly-allocated object, produce a zero,
+// if the load is provably beyond the header of the object.
+// (Also allow a variable load from a fresh array to produce zero.)
+if (ReduceFieldZeroing) {
+Node* value = can_see_stored_value(mem,phase);
+if (value != NULL && value->is_Con())
+return value->bottom_type();
+}
+return _type;
+}
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not?  Match only the address.
+uint LoadNode::match_edge(uint idx) const {
+return idx == MemNode::Address;
+}
+//--------------------------LoadBNode::Ideal--------------------------------------
+//
+//  If the previous store is to the same address as this load,
+//  and the value stored was larger than a byte, replace this load
+//  with the value stored truncated to a byte.  If no truncation is
+//  needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadBNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+Node* mem = in(MemNode::Memory);
+Node* value = can_see_stored_value(mem,phase);
+if( value && !phase->type(value)->higher_equal( _type ) ) {
+Node *result = phase->transform( new (phase->C, 3) LShiftINode(value, phase->intcon(24)) );
+return new (phase->C, 3) RShiftINode(result, phase->intcon(24));
+}
+// Identity call will handle the case where truncation is not needed.
+return LoadNode::Ideal(phase, can_reshape);
+}
+//--------------------------LoadCNode::Ideal--------------------------------------
+//
+//  If the previous store is to the same address as this load,
+//  and the value stored was larger than a char, replace this load
+//  with the value stored truncated to a char.  If no truncation is
+//  needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadCNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+Node* mem = in(MemNode::Memory);
+Node* value = can_see_stored_value(mem,phase);
+if( value && !phase->type(value)->higher_equal( _type ) )
+return new (phase->C, 3) AndINode(value,phase->intcon(0xFFFF));
+// Identity call will handle the case where truncation is not needed.
+return LoadNode::Ideal(phase, can_reshape);
+}
+//--------------------------LoadSNode::Ideal--------------------------------------
+//
+//  If the previous store is to the same address as this load,
+//  and the value stored was larger than a short, replace this load
+//  with the value stored truncated to a short.  If no truncation is
+//  needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadSNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+Node* mem = in(MemNode::Memory);
+Node* value = can_see_stored_value(mem,phase);
+if( value && !phase->type(value)->higher_equal( _type ) ) {
+Node *result = phase->transform( new (phase->C, 3) LShiftINode(value, phase->intcon(16)) );
+return new (phase->C, 3) RShiftINode(result, phase->intcon(16));
+}
+// Identity call will handle the case where truncation is not needed.
+return LoadNode::Ideal(phase, can_reshape);
+}
+//=============================================================================
+//------------------------------Value------------------------------------------
+const Type *LoadKlassNode::Value( PhaseTransform *phase ) const {
+// Either input is TOP ==> the result is TOP
+const Type *t1 = phase->type( in(MemNode::Memory) );
+if (t1 == Type::TOP)  return Type::TOP;
+Node *adr = in(MemNode::Address);
+const Type *t2 = phase->type( adr );
+if (t2 == Type::TOP)  return Type::TOP;
+const TypePtr *tp = t2->is_ptr();
+if (TypePtr::above_centerline(tp->ptr()) ||
+tp->ptr() == TypePtr::Null)  return Type::TOP;
+// Return a more precise klass, if possible
+const TypeInstPtr *tinst = tp->isa_instptr();
+if (tinst != NULL) {
+ciInstanceKlass* ik = tinst->klass()->as_instance_klass();
+int offset = tinst->offset();
+if (ik == phase->C->env()->Class_klass()
+&& (offset == java_lang_Class::klass_offset_in_bytes() ||
+offset == java_lang_Class::array_klass_offset_in_bytes())) {
+// We are loading a special hidden field from a Class mirror object,
+// the field which points to the VM's Klass metaobject.
+ciType* t = tinst->java_mirror_type();
+// java_mirror_type returns non-null for compile-time Class constants.
+if (t != NULL) {
+// constant oop => constant klass
+if (offset == java_lang_Class::array_klass_offset_in_bytes()) {
+return TypeKlassPtr::make(ciArrayKlass::make(t));
+}
+if (!t->is_klass()) {
+// a primitive Class (e.g., int.class) has NULL for a klass field
+return TypePtr::NULL_PTR;
+}
+// (Folds up the 1st indirection in aClassConstant.getModifiers().)
+return TypeKlassPtr::make(t->as_klass());
+}
+// non-constant mirror, so we can't tell what's going on
+}
+if( !ik->is_loaded() )
+return _type;             // Bail out if not loaded
+if (offset == oopDesc::klass_offset_in_bytes()) {
+if (tinst->klass_is_exact()) {
+return TypeKlassPtr::make(ik);
+}
+// See if we can become precise: no subklasses and no interface
+// (Note:  We need to support verified interfaces.)
+if (!ik->is_interface() && !ik->has_subklass()) {
+//assert(!UseExactTypes, "this code should be useless with exact types");
+// Add a dependence; if any subclass added we need to recompile
+if (!ik->is_final()) {
+// %%% should use stronger assert_unique_concrete_subtype instead
+phase->C->dependencies()->assert_leaf_type(ik);
+}
+// Return precise klass
+return TypeKlassPtr::make(ik);
+}
+// Return root of possible klass
+return TypeKlassPtr::make(TypePtr::NotNull, ik, 0/*offset*/);
+}
+}
+// Check for loading klass from an array
+const TypeAryPtr *tary = tp->isa_aryptr();
+if( tary != NULL ) {
+ciKlass *tary_klass = tary->klass();
+if (tary_klass != NULL   // can be NULL when at BOTTOM or TOP
+&& tary->offset() == oopDesc::klass_offset_in_bytes()) {
+if (tary->klass_is_exact()) {
+return TypeKlassPtr::make(tary_klass);
+}
+ciArrayKlass *ak = tary->klass()->as_array_klass();
+// If the klass is an object array, we defer the question to the
+// array component klass.
+if( ak->is_obj_array_klass() ) {
+assert( ak->is_loaded(), "" );
+ciKlass *base_k = ak->as_obj_array_klass()->base_element_klass();
+if( base_k->is_loaded() && base_k->is_instance_klass() ) {
+ciInstanceKlass* ik = base_k->as_instance_klass();
+// See if we can become precise: no subklasses and no interface
+if (!ik->is_interface() && !ik->has_subklass()) {
+//assert(!UseExactTypes, "this code should be useless with exact types");
+// Add a dependence; if any subclass added we need to recompile
+if (!ik->is_final()) {
+phase->C->dependencies()->assert_leaf_type(ik);
+}
+// Return precise array klass
+return TypeKlassPtr::make(ak);
+}
+}
+return TypeKlassPtr::make(TypePtr::NotNull, ak, 0/*offset*/);
+} else {                  // Found a type-array?
+//assert(!UseExactTypes, "this code should be useless with exact types");
+assert( ak->is_type_array_klass(), "" );
+return TypeKlassPtr::make(ak); // These are always precise
+}
+}
+}
+// Check for loading klass from an array klass
+const TypeKlassPtr *tkls = tp->isa_klassptr();
+if (tkls != NULL && !StressReflectiveCode) {
+ciKlass* klass = tkls->klass();
+if( !klass->is_loaded() )
+return _type;             // Bail out if not loaded
+if( klass->is_obj_array_klass() &&
+(uint)tkls->offset() == objArrayKlass::element_klass_offset_in_bytes() + sizeof(oopDesc)) {
+ciKlass* elem = klass->as_obj_array_klass()->element_klass();
+// // Always returning precise element type is incorrect,
+// // e.g., element type could be object and array may contain strings
+// return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
+// The array's TypeKlassPtr was declared 'precise' or 'not precise'
+// according to the element type's subclassing.
+return TypeKlassPtr::make(tkls->ptr(), elem, 0/*offset*/);
+}
+if( klass->is_instance_klass() && tkls->klass_is_exact() &&
+(uint)tkls->offset() == Klass::super_offset_in_bytes() + sizeof(oopDesc)) {
+ciKlass* sup = klass->as_instance_klass()->super();
+// The field is Klass::_super.  Return its (constant) value.
+// (Folds up the 2nd indirection in aClassConstant.getSuperClass().)
+return sup ? TypeKlassPtr::make(sup) : TypePtr::NULL_PTR;
+}
+}
+// Bailout case
+return LoadNode::Value(phase);
+}
+//------------------------------Identity---------------------------------------
+// To clean up reflective code, simplify k.java_mirror.as_klass to plain k.
+// Also feed through the klass in Allocate(...klass...)._klass.
+Node* LoadKlassNode::Identity( PhaseTransform *phase ) {
+Node* x = LoadNode::Identity(phase);
+if (x != this)  return x;
+// Take apart the address into an oop and and offset.
+// Return 'this' if we cannot.
+Node*    adr    = in(MemNode::Address);
+intptr_t offset = 0;
+Node*    base   = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+if (base == NULL)     return this;
+const TypeOopPtr* toop = phase->type(adr)->isa_oopptr();
+if (toop == NULL)     return this;
+// We can fetch the klass directly through an AllocateNode.
+// This works even if the klass is not constant (clone or newArray).
+if (offset == oopDesc::klass_offset_in_bytes()) {
+Node* allocated_klass = AllocateNode::Ideal_klass(base, phase);
+if (allocated_klass != NULL) {
+return allocated_klass;
+}
+}
+// Simplify k.java_mirror.as_klass to plain k, where k is a klassOop.
+// Simplify ak.component_mirror.array_klass to plain ak, ak an arrayKlass.
+// See inline_native_Class_query for occurrences of these patterns.
+// Java Example:  x.getClass().isAssignableFrom(y)
+// Java Example:  Array.newInstance(x.getClass().getComponentType(), n)
+//
+// This improves reflective code, often making the Class
+// mirror go completely dead.  (Current exception:  Class
+// mirrors may appear in debug info, but we could clean them out by
+// introducing a new debug info operator for klassOop.java_mirror).
+if (toop->isa_instptr() && toop->klass() == phase->C->env()->Class_klass()
+&& (offset == java_lang_Class::klass_offset_in_bytes() ||
+offset == java_lang_Class::array_klass_offset_in_bytes())) {
+// We are loading a special hidden field from a Class mirror,
+// the field which points to its Klass or arrayKlass metaobject.
+if (base->is_Load()) {
+Node* adr2 = base->in(MemNode::Address);
+const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr();
+if (tkls != NULL && !tkls->empty()
+&& (tkls->klass()->is_instance_klass() ||
+tkls->klass()->is_array_klass())
+&& adr2->is_AddP()
+) {
+int mirror_field = Klass::java_mirror_offset_in_bytes();
+if (offset == java_lang_Class::array_klass_offset_in_bytes()) {
+mirror_field = in_bytes(arrayKlass::component_mirror_offset());
+}
+if (tkls->offset() == mirror_field + (int)sizeof(oopDesc)) {
+return adr2->in(AddPNode::Base);
+}
+}
+}
+}
+return this;
+}
+//------------------------------Value-----------------------------------------
+const Type *LoadRangeNode::Value( PhaseTransform *phase ) const {
+// Either input is TOP ==> the result is TOP
+const Type *t1 = phase->type( in(MemNode::Memory) );
+if( t1 == Type::TOP ) return Type::TOP;
+Node *adr = in(MemNode::Address);
+const Type *t2 = phase->type( adr );
+if( t2 == Type::TOP ) return Type::TOP;
+const TypePtr *tp = t2->is_ptr();
+if (TypePtr::above_centerline(tp->ptr()))  return Type::TOP;
+const TypeAryPtr *tap = tp->isa_aryptr();
+if( !tap ) return _type;
+return tap->size();
+}
+//------------------------------Identity---------------------------------------
+// Feed through the length in AllocateArray(...length...)._length.
+Node* LoadRangeNode::Identity( PhaseTransform *phase ) {
+Node* x = LoadINode::Identity(phase);
+if (x != this)  return x;
+// Take apart the address into an oop and and offset.
+// Return 'this' if we cannot.
+Node*    adr    = in(MemNode::Address);
+intptr_t offset = 0;
+Node*    base   = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+if (base == NULL)     return this;
+const TypeAryPtr* tary = phase->type(adr)->isa_aryptr();
+if (tary == NULL)     return this;
+// We can fetch the length directly through an AllocateArrayNode.
+// This works even if the length is not constant (clone or newArray).
+if (offset == arrayOopDesc::length_offset_in_bytes()) {
+Node* allocated_length = AllocateArrayNode::Ideal_length(base, phase);
+if (allocated_length != NULL) {
+return allocated_length;
+}
+}
+return this;
+}
+//=============================================================================
+//---------------------------StoreNode::make-----------------------------------
+// Polymorphic factory method:
+StoreNode* StoreNode::make( Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, BasicType bt ) {
+switch (bt) {
+case T_BOOLEAN:
+case T_BYTE:    return new (C, 4) StoreBNode(ctl, mem, adr, adr_type, val);
+case T_INT:     return new (C, 4) StoreINode(ctl, mem, adr, adr_type, val);
+case T_CHAR:
+case T_SHORT:   return new (C, 4) StoreCNode(ctl, mem, adr, adr_type, val);
+case T_LONG:    return new (C, 4) StoreLNode(ctl, mem, adr, adr_type, val);
+case T_FLOAT:   return new (C, 4) StoreFNode(ctl, mem, adr, adr_type, val);
+case T_DOUBLE:  return new (C, 4) StoreDNode(ctl, mem, adr, adr_type, val);
+case T_ADDRESS:
+case T_OBJECT:  return new (C, 4) StorePNode(ctl, mem, adr, adr_type, val);
+}
+ShouldNotReachHere();
+return (StoreNode*)NULL;
+}
+StoreLNode* StoreLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val) {
+bool require_atomic = true;
+return new (C, 4) StoreLNode(ctl, mem, adr, adr_type, val, require_atomic);
+}
+//--------------------------bottom_type----------------------------------------
+const Type *StoreNode::bottom_type() const {
+return Type::MEMORY;
+}
+//------------------------------hash-------------------------------------------
+uint StoreNode::hash() const {
+// unroll addition of interesting fields
+//return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address) + (uintptr_t)in(ValueIn);
+// Since they are not commoned, do not hash them:
+return NO_HASH;
+}
+//------------------------------Ideal------------------------------------------
+// Change back-to-back Store(, p, x) -> Store(m, p, y) to Store(m, p, x).
+// When a store immediately follows a relevant allocation/initialization,
+// try to capture it into the initialization, or hoist it above.
+Node *StoreNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+Node* p = MemNode::Ideal_common(phase, can_reshape);
+if (p)  return (p == NodeSentinel) ? NULL : p;
+Node* mem     = in(MemNode::Memory);
+Node* address = in(MemNode::Address);
+// Back-to-back stores to same address?  Fold em up.
+// Generally unsafe if I have intervening uses...
+if (mem->is_Store() && phase->eqv_uncast(mem->in(MemNode::Address), address)) {
+// Looking at a dead closed cycle of memory?
+assert(mem != mem->in(MemNode::Memory), "dead loop in StoreNode::Ideal");
+assert(Opcode() == mem->Opcode() ||
+phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw,
+"no mismatched stores, except on raw memory");
+if (mem->outcnt() == 1 &&           // check for intervening uses
+mem->as_Store()->memory_size() <= this->memory_size()) {
+// If anybody other than 'this' uses 'mem', we cannot fold 'mem' away.
+// For example, 'mem' might be the final state at a conditional return.
+// Or, 'mem' might be used by some node which is live at the same time
+// 'this' is live, which might be unschedulable.  So, require exactly
+// ONE user, the 'this' store, until such time as we clone 'mem' for
+// each of 'mem's uses (thus making the exactly-1-user-rule hold true).
+if (can_reshape) {  // (%%% is this an anachronism?)
+set_req_X(MemNode::Memory, mem->in(MemNode::Memory),
+phase->is_IterGVN());
+} else {
+// It's OK to do this in the parser, since DU info is always accurate,
+// and the parser always refers to nodes via SafePointNode maps.
+set_req(MemNode::Memory, mem->in(MemNode::Memory));
+}
+return this;
+}
+}
+// Capture an unaliased, unconditional, simple store into an initializer.
+// Or, if it is independent of the allocation, hoist it above the allocation.
+if (ReduceFieldZeroing && /*can_reshape &&*/
+mem->is_Proj() && mem->in(0)->is_Initialize()) {
+InitializeNode* init = mem->in(0)->as_Initialize();
+intptr_t offset = init->can_capture_store(this, phase);
+if (offset > 0) {
+Node* moved = init->capture_store(this, offset, phase);
+// If the InitializeNode captured me, it made a raw copy of me,
+// and I need to disappear.
+if (moved != NULL) {
+// %%% hack to ensure that Ideal returns a new node:
+mem = MergeMemNode::make(phase->C, mem);
+return mem;             // fold me away
+}
+}
+}
+return NULL;                  // No further progress
+}
+//------------------------------Value-----------------------------------------
+const Type *StoreNode::Value( PhaseTransform *phase ) const {
+// Either input is TOP ==> the result is TOP
+const Type *t1 = phase->type( in(MemNode::Memory) );
+if( t1 == Type::TOP ) return Type::TOP;
+const Type *t2 = phase->type( in(MemNode::Address) );
+if( t2 == Type::TOP ) return Type::TOP;
+const Type *t3 = phase->type( in(MemNode::ValueIn) );
+if( t3 == Type::TOP ) return Type::TOP;
+return Type::MEMORY;
+}
+//------------------------------Identity---------------------------------------
+// Remove redundant stores:
+//   Store(m, p, Load(m, p)) changes to m.
+//   Store(, p, x) -> Store(m, p, x) changes to Store(m, p, x).
+Node *StoreNode::Identity( PhaseTransform *phase ) {
+Node* mem = in(MemNode::Memory);
+Node* adr = in(MemNode::Address);
+Node* val = in(MemNode::ValueIn);
+// Load then Store?  Then the Store is useless
+if (val->is_Load() &&
+phase->eqv_uncast( val->in(MemNode::Address), adr ) &&
+phase->eqv_uncast( val->in(MemNode::Memory ), mem ) &&
+val->as_Load()->store_Opcode() == Opcode()) {
+return mem;
+}
+// Two stores in a row of the same value?
+if (mem->is_Store() &&
+phase->eqv_uncast( mem->in(MemNode::Address), adr ) &&
+phase->eqv_uncast( mem->in(MemNode::ValueIn), val ) &&
+mem->Opcode() == Opcode()) {
+return mem;
+}
+// Store of zero anywhere into a freshly-allocated object?
+// Then the store is useless.
+// (It must already have been captured by the InitializeNode.)
+if (ReduceFieldZeroing && phase->type(val)->is_zero_type()) {
+// a newly allocated object is already all-zeroes everywhere
+if (mem->is_Proj() && mem->in(0)->is_Allocate()) {
+return mem;
+}
+// the store may also apply to zero-bits in an earlier object
+Node* prev_mem = find_previous_store(phase);
+// Steps (a), (b):  Walk past independent stores to find an exact match.
+if (prev_mem != NULL) {
+Node* prev_val = can_see_stored_value(prev_mem, phase);
+if (prev_val != NULL && phase->eqv(prev_val, val)) {
+// prev_val and val might differ by a cast; it would be good
+// to keep the more informative of the two.
+return mem;
+}
+}
+}
+return this;
+}
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not?  Match only memory & value
+uint StoreNode::match_edge(uint idx) const {
+return idx == MemNode::Address || idx == MemNode::ValueIn;
+}
+//------------------------------cmp--------------------------------------------
+// Do not common stores up together.  They generally have to be split
+// back up anyways, so do not bother.
+uint StoreNode::cmp( const Node &n ) const {
+return (&n == this);          // Always fail except on self
+}
+//------------------------------Ideal_masked_input-----------------------------
+// Check for a useless mask before a partial-word store
+// (StoreB ... (AndI valIn conIa) )
+// If (conIa & mask == mask) this simplifies to
+// (StoreB ... (valIn) )
+Node *StoreNode::Ideal_masked_input(PhaseGVN *phase, uint mask) {
+Node *val = in(MemNode::ValueIn);
+if( val->Opcode() == Op_AndI ) {
+const TypeInt *t = phase->type( val->in(2) )->isa_int();
+if( t && t->is_con() && (t->get_con() & mask) == mask ) {
+set_req(MemNode::ValueIn, val->in(1));
+return this;
+}
+}
+return NULL;
+}
+//------------------------------Ideal_sign_extended_input----------------------
+// Check for useless sign-extension before a partial-word store
+// (StoreB ... (RShiftI _ (LShiftI _ valIn conIL ) conIR) )
+// If (conIL == conIR && conIR <= num_bits)  this simplifies to
+// (StoreB ... (valIn) )
+Node *StoreNode::Ideal_sign_extended_input(PhaseGVN *phase, int num_bits) {
+Node *val = in(MemNode::ValueIn);
+if( val->Opcode() == Op_RShiftI ) {
+const TypeInt *t = phase->type( val->in(2) )->isa_int();
+if( t && t->is_con() && (t->get_con() <= num_bits) ) {
+Node *shl = val->in(1);
+if( shl->Opcode() == Op_LShiftI ) {
+const TypeInt *t2 = phase->type( shl->in(2) )->isa_int();
+if( t2 && t2->is_con() && (t2->get_con() == t->get_con()) ) {
+set_req(MemNode::ValueIn, shl->in(1));
+return this;
+}
+}
+}
+}
+return NULL;
+}
+//------------------------------value_never_loaded-----------------------------------
+// Determine whether there are any possible loads of the value stored.
+// For simplicity, we actually check if there are any loads from the
+// address stored to, not just for loads of the value stored by this node.
+//
+bool StoreNode::value_never_loaded( PhaseTransform *phase) const {
+Node *adr = in(Address);
+const TypeOopPtr *adr_oop = phase->type(adr)->isa_oopptr();
+if (adr_oop == NULL)
+return false;
+if (!adr_oop->is_instance())
+return false; // if not a distinct instance, there may be aliases of the address
+for (DUIterator_Fast imax, i = adr->fast_outs(imax); i < imax; i++) {
+Node *use = adr->fast_out(i);
+int opc = use->Opcode();
+if (use->is_Load() || use->is_LoadStore()) {
+return false;
+}
+}
+return true;
+}
+//=============================================================================
+//------------------------------Ideal------------------------------------------
+// If the store is from an AND mask that leaves the low bits untouched, then
+// we can skip the AND operation.  If the store is from a sign-extension
+// (a left shift, then right shift) we can skip both.
+Node *StoreBNode::Ideal(PhaseGVN *phase, bool can_reshape){
+Node *progress = StoreNode::Ideal_masked_input(phase, 0xFF);
+if( progress != NULL ) return progress;
+progress = StoreNode::Ideal_sign_extended_input(phase, 24);
+if( progress != NULL ) return progress;
+// Finally check the default case
+return StoreNode::Ideal(phase, can_reshape);
+}
+//=============================================================================
+//------------------------------Ideal------------------------------------------
+// If the store is from an AND mask that leaves the low bits untouched, then
+// we can skip the AND operation
+Node *StoreCNode::Ideal(PhaseGVN *phase, bool can_reshape){
+Node *progress = StoreNode::Ideal_masked_input(phase, 0xFFFF);
+if( progress != NULL ) return progress;
+progress = StoreNode::Ideal_sign_extended_input(phase, 16);
+if( progress != NULL ) return progress;
+// Finally check the default case
+return StoreNode::Ideal(phase, can_reshape);
+}
+//=============================================================================
+//------------------------------Identity---------------------------------------
+Node *StoreCMNode::Identity( PhaseTransform *phase ) {
+// No need to card mark when storing a null ptr
+Node* my_store = in(MemNode::OopStore);
+if (my_store->is_Store()) {
+const Type *t1 = phase->type( my_store->in(MemNode::ValueIn) );
+if( t1 == TypePtr::NULL_PTR ) {
+return in(MemNode::Memory);
+}
+}
+return this;
+}
+//------------------------------Value-----------------------------------------
+const Type *StoreCMNode::Value( PhaseTransform *phase ) const {
+// If extra input is TOP ==> the result is TOP
+const Type *t1 = phase->type( in(MemNode::OopStore) );
+if( t1 == Type::TOP ) return Type::TOP;
+return StoreNode::Value( phase );
+}
+//=============================================================================
+//----------------------------------SCMemProjNode------------------------------
+const Type * SCMemProjNode::Value( PhaseTransform *phase ) const
+{
+return bottom_type();
+}
+//=============================================================================
+LoadStoreNode::LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex ) : Node(5) {
+init_req(MemNode::Control, c  );
+init_req(MemNode::Memory , mem);
+init_req(MemNode::Address, adr);
+init_req(MemNode::ValueIn, val);
+init_req(         ExpectedIn, ex );
+init_class_id(Class_LoadStore);
+}
+//=============================================================================
+//-------------------------------adr_type--------------------------------------
+// Do we Match on this edge index or not?  Do not match memory
+const TypePtr* ClearArrayNode::adr_type() const {
+Node *adr = in(3);
+return MemNode::calculate_adr_type(adr->bottom_type());
+}
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not?  Do not match memory
+uint ClearArrayNode::match_edge(uint idx) const {
+return idx > 1;
+}
+//------------------------------Identity---------------------------------------
+// Clearing a zero length array does nothing
+Node *ClearArrayNode::Identity( PhaseTransform *phase ) {
+return phase->type(in(2))->higher_equal(TypeInt::ZERO)  ? in(1) : this;
+}
+//------------------------------Idealize---------------------------------------
+// Clearing a short array is faster with stores
+Node *ClearArrayNode::Ideal(PhaseGVN *phase, bool can_reshape){
+const int unit = BytesPerLong;
+const TypeX* t = phase->type(in(2))->isa_intptr_t();
+if (!t)  return NULL;
+if (!t->is_con())  return NULL;
+intptr_t raw_count = t->get_con();
+intptr_t size = raw_count;
+if (!Matcher::init_array_count_is_in_bytes) size *= unit;
+// Clearing nothing uses the Identity call.
+// Negative clears are possible on dead ClearArrays
+// (see jck test stmt114.stmt11402.val).
+if (size <= 0 || size % unit != 0)  return NULL;
+intptr_t count = size / unit;
+// Length too long; use fast hardware clear
+if (size > Matcher::init_array_short_size)  return NULL;
+Node *mem = in(1);
+if( phase->type(mem)==Type::TOP ) return NULL;
+Node *adr = in(3);
+const Type* at = phase->type(adr);
+if( at==Type::TOP ) return NULL;
+const TypePtr* atp = at->isa_ptr();
+// adjust atp to be the correct array element address type
+if (atp == NULL)  atp = TypePtr::BOTTOM;
+else              atp = atp->add_offset(Type::OffsetBot);
+// Get base for derived pointer purposes
+if( adr->Opcode() != Op_AddP ) Unimplemented();
+Node *base = adr->in(1);
+Node *zero = phase->makecon(TypeLong::ZERO);
+Node *off  = phase->MakeConX(BytesPerLong);
+mem = new (phase->C, 4) StoreLNode(in(0),mem,adr,atp,zero);
+count--;
+while( count-- ) {
+mem = phase->transform(mem);
+adr = phase->transform(new (phase->C, 4) AddPNode(base,adr,off));
+mem = new (phase->C, 4) StoreLNode(in(0),mem,adr,atp,zero);
+}
+return mem;
+}
+//----------------------------clear_memory-------------------------------------
+// Generate code to initialize object storage to zero.
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+intptr_t start_offset,
+Node* end_offset,
+PhaseGVN* phase) {
+Compile* C = phase->C;
+intptr_t offset = start_offset;
+int unit = BytesPerLong;
+if ((offset % unit) != 0) {
+Node* adr = new (C, 4) AddPNode(dest, dest, phase->MakeConX(offset));
+adr = phase->transform(adr);
+const TypePtr* atp = TypeRawPtr::BOTTOM;
+mem = StoreNode::make(C, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT);
+mem = phase->transform(mem);
+offset += BytesPerInt;
+}
+assert((offset % unit) == 0, "");
+// Initialize the remaining stuff, if any, with a ClearArray.
+return clear_memory(ctl, mem, dest, phase->MakeConX(offset), end_offset, phase);
+}
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+Node* start_offset,
+Node* end_offset,
+PhaseGVN* phase) {
+Compile* C = phase->C;
+int unit = BytesPerLong;
+Node* zbase = start_offset;
+Node* zend  = end_offset;
+// Scale to the unit required by the CPU:
+if (!Matcher::init_array_count_is_in_bytes) {
+Node* shift = phase->intcon(exact_log2(unit));
+zbase = phase->transform( new(C,3) URShiftXNode(zbase, shift) );
+zend  = phase->transform( new(C,3) URShiftXNode(zend,  shift) );
+}
+Node* zsize = phase->transform( new(C,3) SubXNode(zend, zbase) );
+Node* zinit = phase->zerocon((unit == BytesPerLong) ? T_LONG : T_INT);
+// Bulk clear double-words
+Node* adr = phase->transform( new(C,4) AddPNode(dest, dest, start_offset) );
+mem = new (C, 4) ClearArrayNode(ctl, mem, zsize, adr);
+return phase->transform(mem);
+}
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+intptr_t start_offset,
+intptr_t end_offset,
+PhaseGVN* phase) {
+Compile* C = phase->C;
+assert((end_offset % BytesPerInt) == 0, "odd end offset");
+intptr_t done_offset = end_offset;
+if ((done_offset % BytesPerLong) != 0) {
+done_offset -= BytesPerInt;
+}
+if (done_offset > start_offset) {
+mem = clear_memory(ctl, mem, dest,
+start_offset, phase->MakeConX(done_offset), phase);
+}
+if (done_offset < end_offset) { // emit the final 32-bit store
+Node* adr = new (C, 4) AddPNode(dest, dest, phase->MakeConX(done_offset));
+adr = phase->transform(adr);
+const TypePtr* atp = TypeRawPtr::BOTTOM;
+mem = StoreNode::make(C, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT);
+mem = phase->transform(mem);
+done_offset += BytesPerInt;
+}
+assert(done_offset == end_offset, "");
+return mem;
+}
+//=============================================================================
+// Do we match on this edge? No memory edges
+uint StrCompNode::match_edge(uint idx) const {
+return idx == 5 || idx == 6;
+}
+//------------------------------Ideal------------------------------------------
+// Return a node which is more "ideal" than the current node.  Strip out
+// control copies
+Node *StrCompNode::Ideal(PhaseGVN *phase, bool can_reshape){
+return remove_dead_region(phase, can_reshape) ? this : NULL;
+}
+//=============================================================================
+MemBarNode::MemBarNode(Compile* C, int alias_idx, Node* precedent)
+: MultiNode(TypeFunc::Parms + (precedent == NULL? 0: 1)),
+_adr_type(C->get_adr_type(alias_idx))
+{
+init_class_id(Class_MemBar);
+Node* top = C->top();
+init_req(TypeFunc::I_O,top);
+init_req(TypeFunc::FramePtr,top);
+init_req(TypeFunc::ReturnAdr,top);
+if (precedent != NULL)
+init_req(TypeFunc::Parms, precedent);
+}
+//------------------------------cmp--------------------------------------------
+uint MemBarNode::hash() const { return NO_HASH; }
+uint MemBarNode::cmp( const Node &n ) const {
+return (&n == this);          // Always fail except on self
+}
+//------------------------------make-------------------------------------------
+MemBarNode* MemBarNode::make(Compile* C, int opcode, int atp, Node* pn) {
+int len = Precedent + (pn == NULL? 0: 1);
+switch (opcode) {
+case Op_MemBarAcquire:   return new(C, len) MemBarAcquireNode(C,  atp, pn);
+case Op_MemBarRelease:   return new(C, len) MemBarReleaseNode(C,  atp, pn);
+case Op_MemBarVolatile:  return new(C, len) MemBarVolatileNode(C, atp, pn);
+case Op_MemBarCPUOrder:  return new(C, len) MemBarCPUOrderNode(C, atp, pn);
+case Op_Initialize:      return new(C, len) InitializeNode(C,     atp, pn);
+default:                 ShouldNotReachHere(); return NULL;
+}
+}
+//------------------------------Ideal------------------------------------------
+// Return a node which is more "ideal" than the current node.  Strip out
+// control copies
+Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+if (remove_dead_region(phase, can_reshape))  return this;
+return NULL;
+}
+//------------------------------Value------------------------------------------
+const Type *MemBarNode::Value( PhaseTransform *phase ) const {
+if( !in(0) ) return Type::TOP;
+if( phase->type(in(0)) == Type::TOP )
+return Type::TOP;
+return TypeTuple::MEMBAR;
+}
+//------------------------------match------------------------------------------
+// Construct projections for memory.
+Node *MemBarNode::match( const ProjNode *proj, const Matcher *m ) {
+switch (proj->_con) {
+case TypeFunc::Control:
+case TypeFunc::Memory:
+return new (m->C, 1) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
+}
+ShouldNotReachHere();
+return NULL;
+}
+//===========================InitializeNode====================================
+// SUMMARY:
+// This node acts as a memory barrier on raw memory, after some raw stores.
+// The 'cooked' oop value feeds from the Initialize, not the Allocation.
+// The Initialize can 'capture' suitably constrained stores as raw inits.
+// It can coalesce related raw stores into larger units (called 'tiles').
+// It can avoid zeroing new storage for memory units which have raw inits.
+// At macro-expansion, it is marked 'complete', and does not optimize further.
+//
+// EXAMPLE:
+// The object 'new short[2]' occupies 16 bytes in a 32-bit machine.
+//   ctl = incoming control; mem* = incoming memory
+// (Note:  A star * on a memory edge denotes I/O and other standard edges.)
+// First allocate uninitialized memory and fill in the header:
+//   alloc = (Allocate ctl mem* 16 #short[].klass ...)
+//   ctl := alloc.Control; mem* := alloc.Memory*
+//   rawmem = alloc.Memory; rawoop = alloc.RawAddress
+// Then initialize to zero the non-header parts of the raw memory block:
+//   init = (Initialize alloc.Control alloc.Memory* alloc.RawAddress)
+//   ctl := init.Control; mem.SLICE(#short[*]) := init.Memory
+// After the initialize node executes, the object is ready for service:
+//   oop := (CheckCastPP init.Control alloc.RawAddress #short[])
+// Suppose its body is immediately initialized as {1,2}:
+//   store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
+//   store2 = (StoreC init.Control store1      (+ oop 14) 2)
+//   mem.SLICE(#short[*]) := store2
+//
+// DETAILS:
+// An InitializeNode collects and isolates object initialization after
+// an AllocateNode and before the next possible safepoint.  As a
+// memory barrier (MemBarNode), it keeps critical stores from drifting
+// down past any safepoint or any publication of the allocation.
+// Before this barrier, a newly-allocated object may have uninitialized bits.
+// After this barrier, it may be treated as a real oop, and GC is allowed.
+//
+// The semantics of the InitializeNode include an implicit zeroing of
+// the new object from object header to the end of the object.
+// (The object header and end are determined by the AllocateNode.)
+//
+// Certain stores may be added as direct inputs to the InitializeNode.
+// These stores must update raw memory, and they must be to addresses
+// derived from the raw address produced by AllocateNode, and with
+// a constant offset.  They must be ordered by increasing offset.
+// The first one is at in(RawStores), the last at in(req()-1).
+// Unlike most memory operations, they are not linked in a chain,
+// but are displayed in parallel as users of the rawmem output of
+// the allocation.
+//
+// (See comments in InitializeNode::capture_store, which continue
+// the example given above.)
+//
+// When the associated Allocate is macro-expanded, the InitializeNode
+// may be rewritten to optimize collected stores.  A ClearArrayNode
+// may also be created at that point to represent any required zeroing.
+// The InitializeNode is then marked 'complete', prohibiting further
+// capturing of nearby memory operations.
+//
+// During macro-expansion, all captured initializations which store
+// constant values of 32 bits or smaller are coalesced (if advantagous)
+// into larger 'tiles' 32 or 64 bits.  This allows an object to be
+// initialized in fewer memory operations.  Memory words which are
+// covered by neither tiles nor non-constant stores are pre-zeroed
+// by explicit stores of zero.  (The code shape happens to do all
+// zeroing first, then all other stores, with both sequences occurring
+// in order of ascending offsets.)
+//
+// Alternatively, code may be inserted between an AllocateNode and its
+// InitializeNode, to perform arbitrary initialization of the new object.
+// E.g., the object copying intrinsics insert complex data transfers here.
+// The initialization must then be marked as 'complete' disable the
+// built-in zeroing semantics and the collection of initializing stores.
+//
+// While an InitializeNode is incomplete, reads from the memory state
+// produced by it are optimizable if they match the control edge and
+// new oop address associated with the allocation/initialization.
+// They return a stored value (if the offset matches) or else zero.
+// A write to the memory state, if it matches control and address,
+// and if it is to a constant offset, may be 'captured' by the
+// InitializeNode.  It is cloned as a raw memory operation and rewired
+// inside the initialization, to the raw oop produced by the allocation.
+// Operations on addresses which are provably distinct (e.g., to
+// other AllocateNodes) are allowed to bypass the initialization.
+//
+// The effect of all this is to consolidate object initialization
+// (both arrays and non-arrays, both piecewise and bulk) into a
+// single location, where it can be optimized as a unit.
+//
+// Only stores with an offset less than TrackedInitializationLimit words
+// will be considered for capture by an InitializeNode.  This puts a
+// reasonable limit on the complexity of optimized initializations.
+//---------------------------InitializeNode------------------------------------
+InitializeNode::InitializeNode(Compile* C, int adr_type, Node* rawoop)
+: _is_complete(false),
+MemBarNode(C, adr_type, rawoop)
+{
+init_class_id(Class_Initialize);
+assert(adr_type == Compile::AliasIdxRaw, "only valid atp");
+assert(in(RawAddress) == rawoop, "proper init");
+// Note:  allocation() can be NULL, for secondary initialization barriers
+}
+// Since this node is not matched, it will be processed by the
+// register allocator.  Declare that there are no constraints
+// on the allocation of the RawAddress edge.
+const RegMask &InitializeNode::in_RegMask(uint idx) const {
+// This edge should be set to top, by the set_complete.  But be conservative.
+if (idx == InitializeNode::RawAddress)
+return *(Compile::current()->matcher()->idealreg2spillmask[in(idx)->ideal_reg()]);
+return RegMask::Empty;
+}
+Node* InitializeNode::memory(uint alias_idx) {
+Node* mem = in(Memory);
+if (mem->is_MergeMem()) {
+return mem->as_MergeMem()->memory_at(alias_idx);
+} else {
+// incoming raw memory is not split
+return mem;
+}
+}
+bool InitializeNode::is_non_zero() {
+if (is_complete())  return false;
+remove_extra_zeroes();
+return (req() > RawStores);
+}
+void InitializeNode::set_complete(PhaseGVN* phase) {
+assert(!is_complete(), "caller responsibility");
+_is_complete = true;
+// After this node is complete, it contains a bunch of
+// raw-memory initializations.  There is no need for
+// it to have anything to do with non-raw memory effects.
+// Therefore, tell all non-raw users to re-optimize themselves,
+// after skipping the memory effects of this initialization.
+PhaseIterGVN* igvn = phase->is_IterGVN();
+if (igvn)  igvn->add_users_to_worklist(this);
+}
+// convenience function
+// return false if the init contains any stores already
+bool AllocateNode::maybe_set_complete(PhaseGVN* phase) {
+InitializeNode* init = initialization();
+if (init == NULL || init->is_complete())  return false;
+init->remove_extra_zeroes();
+// for now, if this allocation has already collected any inits, bail:
+if (init->is_non_zero())  return false;
+init->set_complete(phase);
+return true;
+}
+void InitializeNode::remove_extra_zeroes() {
+if (req() == RawStores)  return;
+Node* zmem = zero_memory();
+uint fill = RawStores;
+for (uint i = fill; i < req(); i++) {
+Node* n = in(i);
+if (n->is_top() || n == zmem)  continue;  // skip
+if (fill < i)  set_req(fill, n);          // compact
+++fill;
+}
+// delete any empty spaces created:
+while (fill < req()) {
+del_req(fill);
+}
+}
+// Helper for remembering which stores go with which offsets.
+intptr_t InitializeNode::get_store_offset(Node* st, PhaseTransform* phase) {
+if (!st->is_Store())  return -1;  // can happen to dead code via subsume_node
+intptr_t offset = -1;
+Node* base = AddPNode::Ideal_base_and_offset(st->in(MemNode::Address),
+phase, offset);
+if (base == NULL)     return -1;  // something is dead,
+if (offset < 0)       return -1;  //        dead, dead
+return offset;
+}
+// Helper for proving that an initialization expression is
+// "simple enough" to be folded into an object initialization.
+// Attempts to prove that a store's initial value 'n' can be captured
+// within the initialization without creating a vicious cycle, such as:
+//     { Foo p = new Foo(); p.next = p; }
+// True for constants and parameters and small combinations thereof.
+bool InitializeNode::detect_init_independence(Node* n,
+bool st_is_pinned,
+int& count) {
+if (n == NULL)      return true;   // (can this really happen?)
+if (n->is_Proj())   n = n->in(0);
+if (n == this)      return false;  // found a cycle
+if (n->is_Con())    return true;
+if (n->is_Start())  return true;   // params, etc., are OK
+if (n->is_Root())   return true;   // even better
+Node* ctl = n->in(0);
+if (ctl != NULL && !ctl->is_top()) {
+if (ctl->is_Proj())  ctl = ctl->in(0);
+if (ctl == this)  return false;
+// If we already know that the enclosing memory op is pinned right after
+// the init, then any control flow that the store has picked up
+// must have preceded the init, or else be equal to the init.
+// Even after loop optimizations (which might change control edges)
+// a store is never pinned *before* the availability of its inputs.
+if (!MemNode::detect_dominating_control(ctl, this->in(0)))
+return false;                  // failed to prove a good control
+}
+// Check data edges for possible dependencies on 'this'.
+if ((count += 1) > 20)  return false;  // complexity limit
+for (uint i = 1; i < n->req(); i++) {
+Node* m = n->in(i);
+if (m == NULL || m == n || m->is_top())  continue;
+uint first_i = n->find_edge(m);
+if (i != first_i)  continue;  // process duplicate edge just once
+if (!detect_init_independence(m, st_is_pinned, count)) {
+return false;
+}
+}
+return true;
+}
+// Here are all the checks a Store must pass before it can be moved into
+// an initialization.  Returns zero if a check fails.
+// On success, returns the (constant) offset to which the store applies,
+// within the initialized memory.
+intptr_t InitializeNode::can_capture_store(StoreNode* st, PhaseTransform* phase) {
+const int FAIL = 0;
+if (st->req() != MemNode::ValueIn + 1)
+return FAIL;                // an inscrutable StoreNode (card mark?)
+Node* ctl = st->in(MemNode::Control);
+if (!(ctl != NULL && ctl->is_Proj() && ctl->in(0) == this))
+return FAIL;                // must be unconditional after the initialization
+Node* mem = st->in(MemNode::Memory);
+if (!(mem->is_Proj() && mem->in(0) == this))
+return FAIL;                // must not be preceded by other stores
+Node* adr = st->in(MemNode::Address);
+intptr_t offset;
+AllocateNode* alloc = AllocateNode::Ideal_allocation(adr, phase, offset);
+if (alloc == NULL)
+return FAIL;                // inscrutable address
+if (alloc != allocation())
+return FAIL;                // wrong allocation!  (store needs to float up)
+Node* val = st->in(MemNode::ValueIn);
+int complexity_count = 0;
+if (!detect_init_independence(val, true, complexity_count))
+return FAIL;                // stored value must be 'simple enough'
+return offset;                // success
+}
+// Find the captured store in(i) which corresponds to the range
+// [start..start+size) in the initialized object.
+// If there is one, return its index i.  If there isn't, return the
+// negative of the index where it should be inserted.
+// Return 0 if the queried range overlaps an initialization boundary
+// or if dead code is encountered.
+// If size_in_bytes is zero, do not bother with overlap checks.
+int InitializeNode::captured_store_insertion_point(intptr_t start,
+int size_in_bytes,
+PhaseTransform* phase) {
+const int FAIL = 0, MAX_STORE = BytesPerLong;
+if (is_complete())
+return FAIL;                // arraycopy got here first; punt
+assert(allocation() != NULL, "must be present");
+// no negatives, no header fields:
+if (start < (intptr_t) sizeof(oopDesc))  return FAIL;
+if (start < (intptr_t) sizeof(arrayOopDesc) &&
+start < (intptr_t) allocation()->minimum_header_size())  return FAIL;
+// after a certain size, we bail out on tracking all the stores:
+intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
+if (start >= ti_limit)  return FAIL;
+for (uint i = InitializeNode::RawStores, limit = req(); ; ) {
+if (i >= limit)  return -(int)i; // not found; here is where to put it
+Node*    st     = in(i);
+intptr_t st_off = get_store_offset(st, phase);
+if (st_off < 0) {
+if (st != zero_memory()) {
+return FAIL;            // bail out if there is dead garbage
+}
+} else if (st_off > start) {
+// ...we are done, since stores are ordered
+if (st_off < start + size_in_bytes) {
+return FAIL;            // the next store overlaps
+}
+return -(int)i;           // not found; here is where to put it
+} else if (st_off < start) {
+if (size_in_bytes != 0 &&
+start < st_off + MAX_STORE &&
+start < st_off + st->as_Store()->memory_size()) {
+return FAIL;            // the previous store overlaps
+}
+} else {
+if (size_in_bytes != 0 &&
+st->as_Store()->memory_size() != size_in_bytes) {
+return FAIL;            // mismatched store size
+}
+return i;
+}
+++i;
+}
+}
+// Look for a captured store which initializes at the offset 'start'
+// with the given size.  If there is no such store, and no other
+// initialization interferes, then return zero_memory (the memory
+// projection of the AllocateNode).
+Node* InitializeNode::find_captured_store(intptr_t start, int size_in_bytes,
+PhaseTransform* phase) {
+assert(stores_are_sane(phase), "");
+int i = captured_store_insertion_point(start, size_in_bytes, phase);
+if (i == 0) {
+return NULL;                // something is dead
+} else if (i < 0) {
+return zero_memory();       // just primordial zero bits here
+} else {
+Node* st = in(i);           // here is the store at this position
+assert(get_store_offset(st->as_Store(), phase) == start, "sanity");
+return st;
+}
+}
+// Create, as a raw pointer, an address within my new object at 'offset'.
+Node* InitializeNode::make_raw_address(intptr_t offset,
+PhaseTransform* phase) {
+Node* addr = in(RawAddress);
+if (offset != 0) {
+Compile* C = phase->C;
+addr = phase->transform( new (C, 4) AddPNode(C->top(), addr,
+phase->MakeConX(offset)) );
+}
+return addr;
+}
+// Clone the given store, converting it into a raw store
+// initializing a field or element of my new object.
+// Caller is responsible for retiring the original store,
+// with subsume_node or the like.
+//
+// From the example above InitializeNode::InitializeNode,
+// here are the old stores to be captured:
+//   store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
+//   store2 = (StoreC init.Control store1      (+ oop 14) 2)
+//
+// Here is the changed code; note the extra edges on init:
+//   alloc = (Allocate ...)
+//   rawoop = alloc.RawAddress
+//   rawstore1 = (StoreC alloc.Control alloc.Memory (+ rawoop 12) 1)
+//   rawstore2 = (StoreC alloc.Control alloc.Memory (+ rawoop 14) 2)
+//   init = (Initialize alloc.Control alloc.Memory rawoop
+//                      rawstore1 rawstore2)
+//
+Node* InitializeNode::capture_store(StoreNode* st, intptr_t start,
+PhaseTransform* phase) {
+assert(stores_are_sane(phase), "");
+if (start < 0)  return NULL;
+assert(can_capture_store(st, phase) == start, "sanity");
+Compile* C = phase->C;
+int size_in_bytes = st->memory_size();
+int i = captured_store_insertion_point(start, size_in_bytes, phase);
+if (i == 0)  return NULL;     // bail out
+Node* prev_mem = NULL;        // raw memory for the captured store
+if (i > 0) {
+prev_mem = in(i);           // there is a pre-existing store under this one
+set_req(i, C->top());       // temporarily disconnect it
+// See StoreNode::Ideal 'st->outcnt() == 1' for the reason to disconnect.
+} else {
+i = -i;                     // no pre-existing store
+prev_mem = zero_memory();   // a slice of the newly allocated object
+if (i > InitializeNode::RawStores && in(i-1) == prev_mem)
+set_req(--i, C->top());   // reuse this edge; it has been folded away
+else
+ins_req(i, C->top());     // build a new edge
+}
+Node* new_st = st->clone();
+new_st->set_req(MemNode::Control, in(Control));
+new_st->set_req(MemNode::Memory,  prev_mem);
+new_st->set_req(MemNode::Address, make_raw_address(start, phase));
+new_st = phase->transform(new_st);
+// At this point, new_st might have swallowed a pre-existing store
+// at the same offset, or perhaps new_st might have disappeared,
+// if it redundantly stored the same value (or zero to fresh memory).
+// In any case, wire it in:
+set_req(i, new_st);
+// The caller may now kill the old guy.
+DEBUG_ONLY(Node* check_st = find_captured_store(start, size_in_bytes, phase));
+assert(check_st == new_st || check_st == NULL, "must be findable");
+assert(!is_complete(), "");
+return new_st;
+}
+static bool store_constant(jlong* tiles, int num_tiles,
+intptr_t st_off, int st_size,
+jlong con) {
+if ((st_off & (st_size-1)) != 0)
+return false;               // strange store offset (assume size==2**N)
+address addr = (address)tiles + st_off;
+assert(st_off >= 0 && addr+st_size <= (address)&tiles[num_tiles], "oob");
+switch (st_size) {
+case sizeof(jbyte):  *(jbyte*) addr = (jbyte) con; break;
+case sizeof(jchar):  *(jchar*) addr = (jchar) con; break;
+case sizeof(jint):   *(jint*)  addr = (jint)  con; break;
+case sizeof(jlong):  *(jlong*) addr = (jlong) con; break;
+default: return false;        // strange store size (detect size!=2**N here)
+}
+return true;                  // return success to caller
+}
+// Coalesce subword constants into int constants and possibly
+// into long constants.  The goal, if the CPU permits,
+// is to initialize the object with a small number of 64-bit tiles.
+// Also, convert floating-point constants to bit patterns.
+// Non-constants are not relevant to this pass.
+//
+// In terms of the running example on InitializeNode::InitializeNode
+// and InitializeNode::capture_store, here is the transformation
+// of rawstore1 and rawstore2 into rawstore12:
+//   alloc = (Allocate ...)
+//   rawoop = alloc.RawAddress
+//   tile12 = 0x00010002
+//   rawstore12 = (StoreI alloc.Control alloc.Memory (+ rawoop 12) tile12)
+//   init = (Initialize alloc.Control alloc.Memory rawoop rawstore12)
+//
+void
+InitializeNode::coalesce_subword_stores(intptr_t header_size,
+Node* size_in_bytes,
+PhaseGVN* phase) {
+Compile* C = phase->C;
+assert(stores_are_sane(phase), "");
+// Note:  After this pass, they are not completely sane,
+// since there may be some overlaps.
+int old_subword = 0, old_long = 0, new_int = 0, new_long = 0;
+intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
+intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, ti_limit);
+size_limit = MIN2(size_limit, ti_limit);
+size_limit = align_size_up(size_limit, BytesPerLong);
+int num_tiles = size_limit / BytesPerLong;
+// allocate space for the tile map:
+const int small_len = DEBUG_ONLY(true ? 3 :) 30; // keep stack frames small
+jlong  tiles_buf[small_len];
+Node*  nodes_buf[small_len];
+jlong  inits_buf[small_len];
+jlong* tiles = ((num_tiles <= small_len) ? &tiles_buf[0]
+: NEW_RESOURCE_ARRAY(jlong, num_tiles));
+Node** nodes = ((num_tiles <= small_len) ? &nodes_buf[0]
+: NEW_RESOURCE_ARRAY(Node*, num_tiles));
+jlong* inits = ((num_tiles <= small_len) ? &inits_buf[0]
+: NEW_RESOURCE_ARRAY(jlong, num_tiles));
+// tiles: exact bitwise model of all primitive constants
+// nodes: last constant-storing node subsumed into the tiles model
+// inits: which bytes (in each tile) are touched by any initializations
+//// Pass A: Fill in the tile model with any relevant stores.
+Copy::zero_to_bytes(tiles, sizeof(tiles[0]) * num_tiles);
+Copy::zero_to_bytes(nodes, sizeof(nodes[0]) * num_tiles);
+Copy::zero_to_bytes(inits, sizeof(inits[0]) * num_tiles);
+Node* zmem = zero_memory(); // initially zero memory state
+for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
+Node* st = in(i);
+intptr_t st_off = get_store_offset(st, phase);
+// Figure out the store's offset and constant value:
+if (st_off < header_size)             continue; //skip (ignore header)
+if (st->in(MemNode::Memory) != zmem)  continue; //skip (odd store chain)
+int st_size = st->as_Store()->memory_size();
+if (st_off + st_size > size_limit)    break;
+// Record which bytes are touched, whether by constant or not.
+if (!store_constant(inits, num_tiles, st_off, st_size, (jlong) -1))
+continue;                 // skip (strange store size)
+const Type* val = phase->type(st->in(MemNode::ValueIn));
+if (!val->singleton())                continue; //skip (non-con store)
+BasicType type = val->basic_type();
+jlong con = 0;
+switch (type) {
+case T_INT:    con = val->is_int()->get_con();  break;
+case T_LONG:   con = val->is_long()->get_con(); break;
+case T_FLOAT:  con = jint_cast(val->getf());    break;
+case T_DOUBLE: con = jlong_cast(val->getd());   break;
+default:                              continue; //skip (odd store type)
+}
+if (type == T_LONG && Matcher::isSimpleConstant64(con) &&
+st->Opcode() == Op_StoreL) {
+continue;                 // This StoreL is already optimal.
+}
+// Store down the constant.
+store_constant(tiles, num_tiles, st_off, st_size, con);
+intptr_t j = st_off >> LogBytesPerLong;
+if (type == T_INT && st_size == BytesPerInt
+&& (st_off & BytesPerInt) == BytesPerInt) {
+jlong lcon = tiles[j];
+if (!Matcher::isSimpleConstant64(lcon) &&
+st->Opcode() == Op_StoreI) {
+// This StoreI is already optimal by itself.
+jint* intcon = (jint*) &tiles[j];
+intcon[1] = 0;  // undo the store_constant()
+// If the previous store is also optimal by itself, back up and
+// undo the action of the previous loop iteration... if we can.
+// But if we can't, just let the previous half take care of itself.
+st = nodes[j];
+st_off -= BytesPerInt;
+con = intcon[0];
+if (con != 0 && st != NULL && st->Opcode() == Op_StoreI) {
+assert(st_off >= header_size, "still ignoring header");
+assert(get_store_offset(st, phase) == st_off, "must be");
+assert(in(i-1) == zmem, "must be");
+DEBUG_ONLY(const Type* tcon = phase->type(st->in(MemNode::ValueIn)));
+assert(con == tcon->is_int()->get_con(), "must be");
+// Undo the effects of the previous loop trip, which swallowed st:
+intcon[0] = 0;        // undo store_constant()
+set_req(i-1, st);     // undo set_req(i, zmem)
+nodes[j] = NULL;      // undo nodes[j] = st
+--old_subword;        // undo ++old_subword
+}
+continue;               // This StoreI is already optimal.
+}
+}
+// This store is not needed.
+set_req(i, zmem);
+nodes[j] = st;              // record for the moment
+if (st_size < BytesPerLong) // something has changed
+++old_subword;        // includes int/float, but who's counting...
+else  ++old_long;
+}
+if ((old_subword + old_long) == 0)
+return;                     // nothing more to do
+//// Pass B: Convert any non-zero tiles into optimal constant stores.
+// Be sure to insert them before overlapping non-constant stores.
+// (E.g., byte[] x = { 1,2,y,4 }  =>  x[int 0] = 0x01020004, x[2]=y.)
+for (int j = 0; j < num_tiles; j++) {
+jlong con  = tiles[j];
+jlong init = inits[j];
+if (con == 0)  continue;
+jint con0,  con1;           // split the constant, address-wise
+jint init0, init1;          // split the init map, address-wise
+{ union { jlong con; jint intcon[2]; } u;
+u.con = con;
+con0  = u.intcon[0];
+con1  = u.intcon[1];
+u.con = init;
+init0 = u.intcon[0];
+init1 = u.intcon[1];
+}
+Node* old = nodes[j];
+assert(old != NULL, "need the prior store");
+intptr_t offset = (j * BytesPerLong);
+bool split = !Matcher::isSimpleConstant64(con);
+if (offset < header_size) {
+assert(offset + BytesPerInt >= header_size, "second int counts");
+assert(*(jint*)&tiles[j] == 0, "junk in header");
+split = true;             // only the second word counts
+// Example:  int a[] = { 42 ... }
+} else if (con0 == 0 && init0 == -1) {
+split = true;             // first word is covered by full inits
+// Example:  int a[] = { ... foo(), 42 ... }
+} else if (con1 == 0 && init1 == -1) {
+split = true;             // second word is covered by full inits
+// Example:  int a[] = { ... 42, foo() ... }
+}
+// Here's a case where init0 is neither 0 nor -1:
+//   byte a[] = { ... 0,0,foo(),0,  0,0,0,42 ... }
+// Assuming big-endian memory, init0, init1 are 0x0000FF00, 0x000000FF.
+// In this case the tile is not split; it is (jlong)42.
+// The big tile is stored down, and then the foo() value is inserted.
+// (If there were foo(),foo() instead of foo(),0, init0 would be -1.)
+Node* ctl = old->in(MemNode::Control);
+Node* adr = make_raw_address(offset, phase);
+const TypePtr* atp = TypeRawPtr::BOTTOM;
+// One or two coalesced stores to plop down.
+Node*    st[2];
+intptr_t off[2];
+int  nst = 0;
+if (!split) {
+++new_long;
+off[nst] = offset;
+st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+phase->longcon(con), T_LONG);
+} else {
+// Omit either if it is a zero.
+if (con0 != 0) {
+++new_int;
+off[nst]  = offset;
+st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+phase->intcon(con0), T_INT);
+}
+if (con1 != 0) {
+++new_int;
+offset += BytesPerInt;
+adr = make_raw_address(offset, phase);
+off[nst]  = offset;
+st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+phase->intcon(con1), T_INT);
+}
+}
+// Insert second store first, then the first before the second.
+// Insert each one just before any overlapping non-constant stores.
+while (nst > 0) {
+Node* st1 = st[--nst];
+C->copy_node_notes_to(st1, old);
+st1 = phase->transform(st1);
+offset = off[nst];
+assert(offset >= header_size, "do not smash header");
+int ins_idx = captured_store_insertion_point(offset, /*size:*/0, phase);
+guarantee(ins_idx != 0, "must re-insert constant store");
+if (ins_idx < 0)  ins_idx = -ins_idx;  // never overlap
+if (ins_idx > InitializeNode::RawStores && in(ins_idx-1) == zmem)
+set_req(--ins_idx, st1);
+else
+ins_req(ins_idx, st1);
+}
+}
+if (PrintCompilation && WizardMode)
+tty->print_cr("Changed %d/%d subword/long constants into %d/%d int/long",
+old_subword, old_long, new_int, new_long);
+if (C->log() != NULL)
+C->log()->elem("comment that='%d/%d subword/long to %d/%d int/long'",
+old_subword, old_long, new_int, new_long);
+// Clean up any remaining occurrences of zmem:
+remove_extra_zeroes();
+}
+// Explore forward from in(start) to find the first fully initialized
+// word, and return its offset.  Skip groups of subword stores which
+// together initialize full words.  If in(start) is itself part of a
+// fully initialized word, return the offset of in(start).  If there
+// are no following full-word stores, or if something is fishy, return
+// a negative value.
+intptr_t InitializeNode::find_next_fullword_store(uint start, PhaseGVN* phase) {
+int       int_map = 0;
+intptr_t  int_map_off = 0;
+const int FULL_MAP = right_n_bits(BytesPerInt);  // the int_map we hope for
+for (uint i = start, limit = req(); i < limit; i++) {
+Node* st = in(i);
+intptr_t st_off = get_store_offset(st, phase);
+if (st_off < 0)  break;  // return conservative answer
+int st_size = st->as_Store()->memory_size();
+if (st_size >= BytesPerInt && (st_off % BytesPerInt) == 0) {
+return st_off;            // we found a complete word init
+}
+// update the map:
+intptr_t this_int_off = align_size_down(st_off, BytesPerInt);
+if (this_int_off != int_map_off) {
+// reset the map:
+int_map = 0;
+int_map_off = this_int_off;
+}
+int subword_off = st_off - this_int_off;
+int_map |= right_n_bits(st_size) << subword_off;
+if ((int_map & FULL_MAP) == FULL_MAP) {
+return this_int_off;      // we found a complete word init
+}
+// Did this store hit or cross the word boundary?
+intptr_t next_int_off = align_size_down(st_off + st_size, BytesPerInt);
+if (next_int_off == this_int_off + BytesPerInt) {
+// We passed the current int, without fully initializing it.
+int_map_off = next_int_off;
+int_map >>= BytesPerInt;
+} else if (next_int_off > this_int_off + BytesPerInt) {
+// We passed the current and next int.
+return this_int_off + BytesPerInt;
+}
+}
+return -1;
+}
+// Called when the associated AllocateNode is expanded into CFG.
+// At this point, we may perform additional optimizations.
+// Linearize the stores by ascending offset, to make memory
+// activity as coherent as possible.
+Node* InitializeNode::complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
+intptr_t header_size,
+Node* size_in_bytes,
+PhaseGVN* phase) {
+assert(!is_complete(), "not already complete");
+assert(stores_are_sane(phase), "");
+assert(allocation() != NULL, "must be present");
+remove_extra_zeroes();
+if (ReduceFieldZeroing || ReduceBulkZeroing)
+// reduce instruction count for common initialization patterns
+coalesce_subword_stores(header_size, size_in_bytes, phase);
+Node* zmem = zero_memory();   // initially zero memory state
+Node* inits = zmem;           // accumulating a linearized chain of inits
+#ifdef ASSERT
+intptr_t last_init_off = sizeof(oopDesc);  // previous init offset
+intptr_t last_init_end = sizeof(oopDesc);  // previous init offset+size
+intptr_t last_tile_end = sizeof(oopDesc);  // previous tile offset+size
+#endif
+intptr_t zeroes_done = header_size;
+bool do_zeroing = true;       // we might give up if inits are very sparse
+int  big_init_gaps = 0;       // how many large gaps have we seen?
+if (ZeroTLAB)  do_zeroing = false;
+if (!ReduceFieldZeroing && !ReduceBulkZeroing)  do_zeroing = false;
+for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
+Node* st = in(i);
+intptr_t st_off = get_store_offset(st, phase);
+if (st_off < 0)
+break;                    // unknown junk in the inits
+if (st->in(MemNode::Memory) != zmem)
+break;                    // complicated store chains somehow in list
+int st_size = st->as_Store()->memory_size();
+intptr_t next_init_off = st_off + st_size;
+if (do_zeroing && zeroes_done < next_init_off) {
+// See if this store needs a zero before it or under it.
+intptr_t zeroes_needed = st_off;
+if (st_size < BytesPerInt) {
+// Look for subword stores which only partially initialize words.
+// If we find some, we must lay down some word-level zeroes first,
+// underneath the subword stores.
+//
+// Examples:
+//   byte[] a = { p,q,r,s }  =>  a[0]=p,a[1]=q,a[2]=r,a[3]=s
+//   byte[] a = { x,y,0,0 }  =>  a[0..3] = 0, a[0]=x,a[1]=y
+//   byte[] a = { 0,0,z,0 }  =>  a[0..3] = 0, a[2]=z
+//
+// Note:  coalesce_subword_stores may have already done this,
+// if it was prompted by constant non-zero subword initializers.
+// But this case can still arise with non-constant stores.
+intptr_t next_full_store = find_next_fullword_store(i, phase);
+// In the examples above:
+//   in(i)          p   q   r   s     x   y     z
+//   st_off        12  13  14  15    12  13    14
+//   st_size        1   1   1   1     1   1     1
+//   next_full_s.  12  16  16  16    16  16    16
+//   z's_done      12  16  16  16    12  16    12
+//   z's_needed    12  16  16  16    16  16    16
+//   zsize          0   0   0   0     4   0     4
+if (next_full_store < 0) {
+// Conservative tack:  Zero to end of current word.
+zeroes_needed = align_size_up(zeroes_needed, BytesPerInt);
+} else {
+// Zero to beginning of next fully initialized word.
+// Or, don't zero at all, if we are already in that word.
+assert(next_full_store >= zeroes_needed, "must go forward");
+assert((next_full_store & (BytesPerInt-1)) == 0, "even boundary");
+zeroes_needed = next_full_store;
+}
+}
+if (zeroes_needed > zeroes_done) {
+intptr_t zsize = zeroes_needed - zeroes_done;
+// Do some incremental zeroing on rawmem, in parallel with inits.
+zeroes_done = align_size_down(zeroes_done, BytesPerInt);
+rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
+zeroes_done, zeroes_needed,
+phase);
+zeroes_done = zeroes_needed;
+if (zsize > Matcher::init_array_short_size && ++big_init_gaps > 2)
+do_zeroing = false;   // leave the hole, next time
+}
+}
+// Collect the store and move on:
+st->set_req(MemNode::Memory, inits);
+inits = st;                 // put it on the linearized chain
+set_req(i, zmem);           // unhook from previous position
+if (zeroes_done == st_off)
+zeroes_done = next_init_off;
+assert(!do_zeroing || zeroes_done >= next_init_off, "don't miss any");
+#ifdef ASSERT
+// Various order invariants.  Weaker than stores_are_sane because
+// a large constant tile can be filled in by smaller non-constant stores.
+assert(st_off >= last_init_off, "inits do not reverse");
+last_init_off = st_off;
+const Type* val = NULL;
+if (st_size >= BytesPerInt &&
+(val = phase->type(st->in(MemNode::ValueIn)))->singleton() &&
+(int)val->basic_type() < (int)T_OBJECT) {
+assert(st_off >= last_tile_end, "tiles do not overlap");
+assert(st_off >= last_init_end, "tiles do not overwrite inits");
+last_tile_end = MAX2(last_tile_end, next_init_off);
+} else {
+intptr_t st_tile_end = align_size_up(next_init_off, BytesPerLong);
+assert(st_tile_end >= last_tile_end, "inits stay with tiles");
+assert(st_off      >= last_init_end, "inits do not overlap");
+last_init_end = next_init_off;  // it's a non-tile
+}
+#endif //ASSERT
+}
+remove_extra_zeroes();        // clear out all the zmems left over
+add_req(inits);
+if (!ZeroTLAB) {
+// If anything remains to be zeroed, zero it all now.
+zeroes_done = align_size_down(zeroes_done, BytesPerInt);
+// if it is the last unused 4 bytes of an instance, forget about it
+intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, max_jint);
+if (zeroes_done + BytesPerLong >= size_limit) {
+assert(allocation() != NULL, "");
+Node* klass_node = allocation()->in(AllocateNode::KlassNode);
+ciKlass* k = phase->type(klass_node)->is_klassptr()->klass();
+if (zeroes_done == k->layout_helper())
+zeroes_done = size_limit;
+}
+if (zeroes_done < size_limit) {
+rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
+zeroes_done, size_in_bytes, phase);
+}
+}
+set_complete(phase);
+return rawmem;
+}
+#ifdef ASSERT
+bool InitializeNode::stores_are_sane(PhaseTransform* phase) {
+if (is_complete())
+return true;                // stores could be anything at this point
+intptr_t last_off = sizeof(oopDesc);
+for (uint i = InitializeNode::RawStores; i < req(); i++) {
+Node* st = in(i);
+intptr_t st_off = get_store_offset(st, phase);
+if (st_off < 0)  continue;  // ignore dead garbage
+if (last_off > st_off) {
+tty->print_cr("*** bad store offset at %d: %d > %d", i, last_off, st_off);
+this->dump(2);
+assert(false, "ascending store offsets");
+return false;
+}
+last_off = st_off + st->as_Store()->memory_size();
+}
+return true;
+}
+#endif //ASSERT
+//============================MergeMemNode=====================================
+//
+// SEMANTICS OF MEMORY MERGES:  A MergeMem is a memory state assembled from several
+// contributing store or call operations.  Each contributor provides the memory
+// state for a particular "alias type" (see Compile::alias_type).  For example,
+// if a MergeMem has an input X for alias category #6, then any memory reference
+// to alias category #6 may use X as its memory state input, as an exact equivalent
+// to using the MergeMem as a whole.
+//   Load<6>( MergeMem(<6>: X, ...), p ) <==> Load<6>(X,p)
+//
+// (Here, the <N> notation gives the index of the relevant adr_type.)
+//
+// In one special case (and more cases in the future), alias categories overlap.
+// The special alias category "Bot" (Compile::AliasIdxBot) includes all memory
+// states.  Therefore, if a MergeMem has only one contributing input W for Bot,
+// it is exactly equivalent to that state W:
+//   MergeMem(<Bot>: W) <==> W
+//
+// Usually, the merge has more than one input.  In that case, where inputs
+// overlap (i.e., one is Bot), the narrower alias type determines the memory
+// state for that type, and the wider alias type (Bot) fills in everywhere else:
+//   Load<5>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<5>(W,p)
+//   Load<6>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<6>(X,p)
+//
+// A merge can take a "wide" memory state as one of its narrow inputs.
+// This simply means that the merge observes out only the relevant parts of
+// the wide input.  That is, wide memory states arriving at narrow merge inputs
+// are implicitly "filtered" or "sliced" as necessary.  (This is rare.)
+//
+// These rules imply that MergeMem nodes may cascade (via their <Bot> links),
+// and that memory slices "leak through":
+//   MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y)) <==> MergeMem(<Bot>: W, <7>: Y)
+//
+// But, in such a cascade, repeated memory slices can "block the leak":
+//   MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y), <7>: Y') <==> MergeMem(<Bot>: W, <7>: Y')
+//
+// In the last example, Y is not part of the combined memory state of the
+// outermost MergeMem.  The system must, of course, prevent unschedulable
+// memory states from arising, so you can be sure that the state Y is somehow
+// a precursor to state Y'.
+//
+//
+// REPRESENTATION OF MEMORY MERGES: The indexes used to address the Node::in array
+// of each MergeMemNode array are exactly the numerical alias indexes, including
+// but not limited to AliasIdxTop, AliasIdxBot, and AliasIdxRaw.  The functions
+// Compile::alias_type (and kin) produce and manage these indexes.
+//
+// By convention, the value of in(AliasIdxTop) (i.e., in(1)) is always the top node.
+// (Note that this provides quick access to the top node inside MergeMem methods,
+// without the need to reach out via TLS to Compile::current.)
+//
+// As a consequence of what was just described, a MergeMem that represents a full
+// memory state has an edge in(AliasIdxBot) which is a "wide" memory state,
+// containing all alias categories.
+//
+// MergeMem nodes never (?) have control inputs, so in(0) is NULL.
+//
+// All other edges in(N) (including in(AliasIdxRaw), which is in(3)) are either
+// a memory state for the alias type <N>, or else the top node, meaning that
+// there is no particular input for that alias type.  Note that the length of
+// a MergeMem is variable, and may be extended at any time to accommodate new
+// memory states at larger alias indexes.  When merges grow, they are of course
+// filled with "top" in the unused in() positions.
+//
+// This use of top is named "empty_memory()", or "empty_mem" (no-memory) as a variable.
+// (Top was chosen because it works smoothly with passes like GCM.)
+//
+// For convenience, we hardwire the alias index for TypeRawPtr::BOTTOM.  (It is
+// the type of random VM bits like TLS references.)  Since it is always the
+// first non-Bot memory slice, some low-level loops use it to initialize an
+// index variable:  for (i = AliasIdxRaw; i < req(); i++).
+//
+//
+// ACCESSORS:  There is a special accessor MergeMemNode::base_memory which returns
+// the distinguished "wide" state.  The accessor MergeMemNode::memory_at(N) returns
+// the memory state for alias type <N>, or (if there is no particular slice at <N>,
+// it returns the base memory.  To prevent bugs, memory_at does not accept <Top>
+// or <Bot> indexes.  The iterator MergeMemStream provides robust iteration over
+// MergeMem nodes or pairs of such nodes, ensuring that the non-top edges are visited.
+//
+// %%%% We may get rid of base_memory as a separate accessor at some point; it isn't
+// really that different from the other memory inputs.  An abbreviation called
+// "bot_memory()" for "memory_at(AliasIdxBot)" would keep code tidy.
+//
+//
+// PARTIAL MEMORY STATES:  During optimization, MergeMem nodes may arise that represent
+// partial memory states.  When a Phi splits through a MergeMem, the copy of the Phi
+// that "emerges though" the base memory will be marked as excluding the alias types
+// of the other (narrow-memory) copies which "emerged through" the narrow edges:
+//
+//   Phi<Bot>(U, MergeMem(<Bot>: W, <8>: Y))
+//     ==Ideal=>  MergeMem(<Bot>: Phi<Bot-8>(U, W), Phi<8>(U, Y))
+//
+// This strange "subtraction" effect is necessary to ensure IGVN convergence.
+// (It is currently unimplemented.)  As you can see, the resulting merge is
+// actually a disjoint union of memory states, rather than an overlay.
+//
+//------------------------------MergeMemNode-----------------------------------
+Node* MergeMemNode::make_empty_memory() {
+Node* empty_memory = (Node*) Compile::current()->top();
+assert(empty_memory->is_top(), "correct sentinel identity");
+return empty_memory;
+}
+MergeMemNode::MergeMemNode(Node *new_base) : Node(1+Compile::AliasIdxRaw) {
+init_class_id(Class_MergeMem);
+// all inputs are nullified in Node::Node(int)
+// set_input(0, NULL);  // no control input
+// Initialize the edges uniformly to top, for starters.
+Node* empty_mem = make_empty_memory();
+for (uint i = Compile::AliasIdxTop; i < req(); i++) {
+init_req(i,empty_mem);
+}
+assert(empty_memory() == empty_mem, "");
+if( new_base != NULL && new_base->is_MergeMem() ) {
+MergeMemNode* mdef = new_base->as_MergeMem();
+assert(mdef->empty_memory() == empty_mem, "consistent sentinels");
+for (MergeMemStream mms(this, mdef); mms.next_non_empty2(); ) {
+mms.set_memory(mms.memory2());
+}
+assert(base_memory() == mdef->base_memory(), "");
+} else {
+set_base_memory(new_base);
+}
+}
+// Make a new, untransformed MergeMem with the same base as 'mem'.
+// If mem is itself a MergeMem, populate the result with the same edges.
+MergeMemNode* MergeMemNode::make(Compile* C, Node* mem) {
+return new(C, 1+Compile::AliasIdxRaw) MergeMemNode(mem);
+}
+//------------------------------cmp--------------------------------------------
+uint MergeMemNode::hash() const { return NO_HASH; }
+uint MergeMemNode::cmp( const Node &n ) const {
+return (&n == this);          // Always fail except on self
+}
+//------------------------------Identity---------------------------------------
+Node* MergeMemNode::Identity(PhaseTransform *phase) {
+// Identity if this merge point does not record any interesting memory
+// disambiguations.
+Node* base_mem = base_memory();
+Node* empty_mem = empty_memory();
+if (base_mem != empty_mem) {  // Memory path is not dead?
+for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+Node* mem = in(i);
+if (mem != empty_mem && mem != base_mem) {
+return this;            // Many memory splits; no change
+}
+}
+}
+return base_mem;              // No memory splits; ID on the one true input
+}
+//------------------------------Ideal------------------------------------------
+// This method is invoked recursively on chains of MergeMem nodes
+Node *MergeMemNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+// Remove chain'd MergeMems
+//
+// This is delicate, because the each "in(i)" (i >= Raw) is interpreted
+// relative to the "in(Bot)".  Since we are patching both at the same time,
+// we have to be careful to read each "in(i)" relative to the old "in(Bot)",
+// but rewrite each "in(i)" relative to the new "in(Bot)".
+Node *progress = NULL;
+Node* old_base = base_memory();
+Node* empty_mem = empty_memory();
+if (old_base == empty_mem)
+return NULL; // Dead memory path.
+MergeMemNode* old_mbase;
+if (old_base != NULL && old_base->is_MergeMem())
+old_mbase = old_base->as_MergeMem();
+else
+old_mbase = NULL;
+Node* new_base = old_base;
+// simplify stacked MergeMems in base memory
+if (old_mbase)  new_base = old_mbase->base_memory();
+// the base memory might contribute new slices beyond my req()
+if (old_mbase)  grow_to_match(old_mbase);
+// Look carefully at the base node if it is a phi.
+PhiNode* phi_base;
+if (new_base != NULL && new_base->is_Phi())
+phi_base = new_base->as_Phi();
+else
+phi_base = NULL;
+Node*    phi_reg = NULL;
+uint     phi_len = (uint)-1;
+if (phi_base != NULL && !phi_base->is_copy()) {
+// do not examine phi if degraded to a copy
+phi_reg = phi_base->region();
+phi_len = phi_base->req();
+// see if the phi is unfinished
+for (uint i = 1; i < phi_len; i++) {
+if (phi_base->in(i) == NULL) {
+// incomplete phi; do not look at it yet!
+phi_reg = NULL;
+phi_len = (uint)-1;
+break;
+}
+}
+}
+// Note:  We do not call verify_sparse on entry, because inputs
+// can normalize to the base_memory via subsume_node or similar
+// mechanisms.  This method repairs that damage.
+assert(!old_mbase || old_mbase->is_empty_memory(empty_mem), "consistent sentinels");
+// Look at each slice.
+for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+Node* old_in = in(i);
+// calculate the old memory value
+Node* old_mem = old_in;
+if (old_mem == empty_mem)  old_mem = old_base;
+assert(old_mem == memory_at(i), "");
+// maybe update (reslice) the old memory value
+// simplify stacked MergeMems
+Node* new_mem = old_mem;
+MergeMemNode* old_mmem;
+if (old_mem != NULL && old_mem->is_MergeMem())
+old_mmem = old_mem->as_MergeMem();
+else
+old_mmem = NULL;
+if (old_mmem == this) {
+// This can happen if loops break up and safepoints disappear.
+// A merge of BotPtr (default) with a RawPtr memory derived from a
+// safepoint can be rewritten to a merge of the same BotPtr with
+// the BotPtr phi coming into the loop.  If that phi disappears
+// also, we can end up with a self-loop of the mergemem.
+// In general, if loops degenerate and memory effects disappear,
+// a mergemem can be left looking at itself.  This simply means
+// that the mergemem's default should be used, since there is
+// no longer any apparent effect on this slice.
+// Note: If a memory slice is a MergeMem cycle, it is unreachable
+//       from start.  Update the input to TOP.
+new_mem = (new_base == this || new_base == empty_mem)? empty_mem : new_base;
+}
+else if (old_mmem != NULL) {
+new_mem = old_mmem->memory_at(i);
+}
+// else preceeding memory was not a MergeMem
+// replace equivalent phis (unfortunately, they do not GVN together)
+if (new_mem != NULL && new_mem != new_base &&
+new_mem->req() == phi_len && new_mem->in(0) == phi_reg) {
+if (new_mem->is_Phi()) {
+PhiNode* phi_mem = new_mem->as_Phi();
+for (uint i = 1; i < phi_len; i++) {
+if (phi_base->in(i) != phi_mem->in(i)) {
+phi_mem = NULL;
+break;
+}
+}
+if (phi_mem != NULL) {
+// equivalent phi nodes; revert to the def
+new_mem = new_base;
+}
+}
+}
+// maybe store down a new value
+Node* new_in = new_mem;
+if (new_in == new_base)  new_in = empty_mem;
+if (new_in != old_in) {
+// Warning:  Do not combine this "if" with the previous "if"
+// A memory slice might have be be rewritten even if it is semantically
+// unchanged, if the base_memory value has changed.
+set_req(i, new_in);
+progress = this;          // Report progress
+}
+}
+if (new_base != old_base) {
+set_req(Compile::AliasIdxBot, new_base);
+// Don't use set_base_memory(new_base), because we need to update du.
+assert(base_memory() == new_base, "");
+progress = this;
+}
+if( base_memory() == this ) {
+// a self cycle indicates this memory path is dead
+set_req(Compile::AliasIdxBot, empty_mem);
+}
+// Resolve external cycles by calling Ideal on a MergeMem base_memory
+// Recursion must occur after the self cycle check above
+if( base_memory()->is_MergeMem() ) {
+MergeMemNode *new_mbase = base_memory()->as_MergeMem();
+Node *m = phase->transform(new_mbase);  // Rollup any cycles
+if( m != NULL && (m->is_top() ||
+m->is_MergeMem() && m->as_MergeMem()->base_memory() == empty_mem) ) {
+// propagate rollup of dead cycle to self
+set_req(Compile::AliasIdxBot, empty_mem);
+}
+}
+if( base_memory() == empty_mem ) {
+progress = this;
+// Cut inputs during Parse phase only.
+// During Optimize phase a dead MergeMem node will be subsumed by Top.
+if( !can_reshape ) {
+for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+if( in(i) != empty_mem ) { set_req(i, empty_mem); }
+}
+}
+}
+if( !progress && base_memory()->is_Phi() && can_reshape ) {
+// Check if PhiNode::Ideal's "Split phis through memory merges"
+// transform should be attempted. Look for this->phi->this cycle.
+uint merge_width = req();
+if (merge_width > Compile::AliasIdxRaw) {
+PhiNode* phi = base_memory()->as_Phi();
+for( uint i = 1; i < phi->req(); ++i ) {// For all paths in
+if (phi->in(i) == this) {
+phase->is_IterGVN()->_worklist.push(phi);
+break;
+}
+}
+}
+}
+assert(verify_sparse(), "please, no dups of base");
+return progress;
+}
+//-------------------------set_base_memory-------------------------------------
+void MergeMemNode::set_base_memory(Node *new_base) {
+Node* empty_mem = empty_memory();
+set_req(Compile::AliasIdxBot, new_base);
+assert(memory_at(req()) == new_base, "must set default memory");
+// Clear out other occurrences of new_base:
+if (new_base != empty_mem) {
+for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+if (in(i) == new_base)  set_req(i, empty_mem);
+}
+}
+}
+//------------------------------out_RegMask------------------------------------
+const RegMask &MergeMemNode::out_RegMask() const {
+return RegMask::Empty;
+}
+//------------------------------dump_spec--------------------------------------
+#ifndef PRODUCT
+void MergeMemNode::dump_spec(outputStream *st) const {
+st->print(" {");
+Node* base_mem = base_memory();
+for( uint i = Compile::AliasIdxRaw; i < req(); i++ ) {
+Node* mem = memory_at(i);
+if (mem == base_mem) { st->print(" -"); continue; }
+st->print( " N%d:", mem->_idx );
+Compile::current()->get_adr_type(i)->dump_on(st);
+}
+st->print(" }");
+}
+#endif // !PRODUCT
+#ifdef ASSERT
+static bool might_be_same(Node* a, Node* b) {
+if (a == b)  return true;
+if (!(a->is_Phi() || b->is_Phi()))  return false;
+// phis shift around during optimization
+return true;  // pretty stupid...
+}
+// verify a narrow slice (either incoming or outgoing)
+static void verify_memory_slice(const MergeMemNode* m, int alias_idx, Node* n) {
+if (!VerifyAliases)       return;  // don't bother to verify unless requested
+if (is_error_reported())  return;  // muzzle asserts when debugging an error
+if (Node::in_dump())      return;  // muzzle asserts when printing
+assert(alias_idx >= Compile::AliasIdxRaw, "must not disturb base_memory or sentinel");
+assert(n != NULL, "");
+// Elide intervening MergeMem's
+while (n->is_MergeMem()) {
+n = n->as_MergeMem()->memory_at(alias_idx);
+}
+Compile* C = Compile::current();
+const TypePtr* n_adr_type = n->adr_type();
+if (n == m->empty_memory()) {
+// Implicit copy of base_memory()
+} else if (n_adr_type != TypePtr::BOTTOM) {
+assert(n_adr_type != NULL, "new memory must have a well-defined adr_type");
+assert(C->must_alias(n_adr_type, alias_idx), "new memory must match selected slice");
+} else {
+// A few places like make_runtime_call "know" that VM calls are narrow,
+// and can be used to update only the VM bits stored as TypeRawPtr::BOTTOM.
+bool expected_wide_mem = false;
+if (n == m->base_memory()) {
+expected_wide_mem = true;
+} else if (alias_idx == Compile::AliasIdxRaw ||
+n == m->memory_at(Compile::AliasIdxRaw)) {
+expected_wide_mem = true;
+} else if (!C->alias_type(alias_idx)->is_rewritable()) {
+// memory can "leak through" calls on channels that
+// are write-once.  Allow this also.
+expected_wide_mem = true;
+}
+assert(expected_wide_mem, "expected narrow slice replacement");
+}
+}
+#else // !ASSERT
+#define verify_memory_slice(m,i,n) (0)  // PRODUCT version is no-op
+#endif
+//-----------------------------memory_at---------------------------------------
+Node* MergeMemNode::memory_at(uint alias_idx) const {
+assert(alias_idx >= Compile::AliasIdxRaw ||
+alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
+"must avoid base_memory and AliasIdxTop");
+// Otherwise, it is a narrow slice.
+Node* n = alias_idx < req() ? in(alias_idx) : empty_memory();
+Compile *C = Compile::current();
+if (is_empty_memory(n)) {
+// the array is sparse; empty slots are the "top" node
+n = base_memory();
+assert(Node::in_dump()
+|| n == NULL || n->bottom_type() == Type::TOP
+|| n->adr_type() == TypePtr::BOTTOM
+|| n->adr_type() == TypeRawPtr::BOTTOM
+|| Compile::current()->AliasLevel() == 0,
+"must be a wide memory");
+// AliasLevel == 0 if we are organizing the memory states manually.
+// See verify_memory_slice for comments on TypeRawPtr::BOTTOM.
+} else {
+// make sure the stored slice is sane
+#ifdef ASSERT
+if (is_error_reported() || Node::in_dump()) {
+} else if (might_be_same(n, base_memory())) {
+// Give it a pass:  It is a mostly harmless repetition of the base.
+// This can arise normally from node subsumption during optimization.
+} else {
+verify_memory_slice(this, alias_idx, n);
+}
+#endif
+}
+return n;
+}
+//---------------------------set_memory_at-------------------------------------
+void MergeMemNode::set_memory_at(uint alias_idx, Node *n) {
+verify_memory_slice(this, alias_idx, n);
+Node* empty_mem = empty_memory();
+if (n == base_memory())  n = empty_mem;  // collapse default
+uint need_req = alias_idx+1;
+if (req() < need_req) {
+if (n == empty_mem)  return;  // already the default, so do not grow me
+// grow the sparse array
+do {
+add_req(empty_mem);
+} while (req() < need_req);
+}
+set_req( alias_idx, n );
+}
+//--------------------------iteration_setup------------------------------------
+void MergeMemNode::iteration_setup(const MergeMemNode* other) {
+if (other != NULL) {
+grow_to_match(other);
+// invariant:  the finite support of mm2 is within mm->req()
+#ifdef ASSERT
+for (uint i = req(); i < other->req(); i++) {
+assert(other->is_empty_memory(other->in(i)), "slice left uncovered");
+}
+#endif
+}
+// Replace spurious copies of base_memory by top.
+Node* base_mem = base_memory();
+if (base_mem != NULL && !base_mem->is_top()) {
+for (uint i = Compile::AliasIdxBot+1, imax = req(); i < imax; i++) {
+if (in(i) == base_mem)
+set_req(i, empty_memory());
+}
+}
+}
+//---------------------------grow_to_match-------------------------------------
+void MergeMemNode::grow_to_match(const MergeMemNode* other) {
+Node* empty_mem = empty_memory();
+assert(other->is_empty_memory(empty_mem), "consistent sentinels");
+// look for the finite support of the other memory
+for (uint i = other->req(); --i >= req(); ) {
+if (other->in(i) != empty_mem) {
+uint new_len = i+1;
+while (req() < new_len)  add_req(empty_mem);
+break;
+}
+}
+}
+//---------------------------verify_sparse-------------------------------------
+#ifndef PRODUCT
+bool MergeMemNode::verify_sparse() const {
+assert(is_empty_memory(make_empty_memory()), "sane sentinel");
+Node* base_mem = base_memory();
+// The following can happen in degenerate cases, since empty==top.
+if (is_empty_memory(base_mem))  return true;
+for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+assert(in(i) != NULL, "sane slice");
+if (in(i) == base_mem)  return false;  // should have been the sentinel value!
+}
+return true;
+}
+bool MergeMemStream::match_memory(Node* mem, const MergeMemNode* mm, int idx) {
+Node* n;
+n = mm->in(idx);
+if (mem == n)  return true;  // might be empty_memory()
+n = (idx == Compile::AliasIdxBot)? mm->base_memory(): mm->memory_at(idx);
+if (mem == n)  return true;
+while (n->is_Phi() && (n = n->as_Phi()->is_copy()) != NULL) {
+if (mem == n)  return true;
+if (n == NULL)  break;
+}
+return false;
+}
+#endif // !PRODUCT

Mercurial > hg > graal-compiler

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