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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * 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.

 *

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#include "opto/loopnode.hpp"

#include "opto/node.hpp"

#include "opto/phaseX.hpp"

#include "opto/vectornode.hpp"

#include "utilities/growableArray.hpp"

#include "libadt/dict.hpp"

//

//                  S U P E R W O R D   T R A N S F O R M

//

// SuperWords are short, fixed length vectors.

//

// Algorithm from:

//

// Exploiting SuperWord Level Parallelism with

//   Multimedia Instruction Sets

// by

//   Samuel Larsen and Saman Amarasinghe

//   MIT Laboratory for Computer Science

// date

//   May 2000

// published in

//   ACM SIGPLAN Notices

//   Proceedings of ACM PLDI '00,  Volume 35 Issue 5

//

// Definition 3.1 A Pack is an n-tuple, <s1, ...,sn>, where

// s1,...,sn are independent isomorphic statements in a basic

// block.

//

// Definition 3.2 A PackSet is a set of Packs.

//

// Definition 3.3 A Pair is a Pack of size two, where the

// first statement is considered the left element, and the

// second statement is considered the right element.

class SWPointer;

class OrderedPair;

// ========================= Dependence Graph =====================

class DepMem;

//------------------------------DepEdge---------------------------

// An edge in the dependence graph.  The edges incident to a dependence

// node are threaded through _next_in for incoming edges and _next_out

// for outgoing edges.

class DepEdge : public ResourceObj {

 protected:

  DepMem* _pred;

  DepMem* _succ;

  DepEdge* _next_in;   // list of in edges, null terminated

  DepEdge* _next_out;  // list of out edges, null terminated

 public:

  DepEdge(DepMem* pred, DepMem* succ, DepEdge* next_in, DepEdge* next_out) :

    _pred(pred), _succ(succ), _next_in(next_in), _next_out(next_out) {}

  DepEdge* next_in()  { return _next_in; }

  DepEdge* next_out() { return _next_out; }

  DepMem*  pred()     { return _pred; }

  DepMem*  succ()     { return _succ; }

  void print();

};

//------------------------------DepMem---------------------------

// A node in the dependence graph.  _in_head starts the threaded list of

// incoming edges, and _out_head starts the list of outgoing edges.

class DepMem : public ResourceObj {

 protected:

  Node*    _node;     // Corresponding ideal node

  DepEdge* _in_head;  // Head of list of in edges, null terminated

  DepEdge* _out_head; // Head of list of out edges, null terminated

 public:

  DepMem(Node* node) : _node(node), _in_head(NULL), _out_head(NULL) {}

  Node*    node()                { return _node;     }

  DepEdge* in_head()             { return _in_head;  }

  DepEdge* out_head()            { return _out_head; }

  void set_in_head(DepEdge* hd)  { _in_head = hd;    }

  void set_out_head(DepEdge* hd) { _out_head = hd;   }

  int in_cnt();  // Incoming edge count

  int out_cnt(); // Outgoing edge count

  void print();

};

//------------------------------DepGraph---------------------------

class DepGraph {

 protected:

  Arena* _arena;

  GrowableArray<DepMem*> _map;

  DepMem* _root;

  DepMem* _tail;

 public:

  DepGraph(Arena* a) : _arena(a), _map(a, 8,  0, NULL) {

    _root = new (_arena) DepMem(NULL);

    _tail = new (_arena) DepMem(NULL);

  }

  DepMem* root() { return _root; }

  DepMem* tail() { return _tail; }

  // Return dependence node corresponding to an ideal node

  DepMem* dep(Node* node) { return _map.at(node->_idx); }

  // Make a new dependence graph node for an ideal node.

  DepMem* make_node(Node* node);

  // Make a new dependence graph edge dprec->dsucc

  DepEdge* make_edge(DepMem* dpred, DepMem* dsucc);

  DepEdge* make_edge(Node* pred,   Node* succ)   { return make_edge(dep(pred), dep(succ)); }

  DepEdge* make_edge(DepMem* pred, Node* succ)   { return make_edge(pred,      dep(succ)); }

  DepEdge* make_edge(Node* pred,   DepMem* succ) { return make_edge(dep(pred), succ);      }

  void init() { _map.clear(); } // initialize

  void print(Node* n)   { dep(n)->print(); }

  void print(DepMem* d) { d->print(); }

};

//------------------------------DepPreds---------------------------

// Iterator over predecessors in the dependence graph and

// non-memory-graph inputs of ideal nodes.

class DepPreds : public StackObj {

private:

  Node*    _n;

  int      _next_idx, _end_idx;

  DepEdge* _dep_next;

  Node*    _current;

  bool     _done;

public:

  DepPreds(Node* n, DepGraph& dg);

  Node* current() { return _current; }

  bool  done()    { return _done; }

  void  next();

};

//------------------------------DepSuccs---------------------------

// Iterator over successors in the dependence graph and

// non-memory-graph outputs of ideal nodes.

class DepSuccs : public StackObj {

private:

  Node*    _n;

  int      _next_idx, _end_idx;

  DepEdge* _dep_next;

  Node*    _current;

  bool     _done;

public:

  DepSuccs(Node* n, DepGraph& dg);

  Node* current() { return _current; }

  bool  done()    { return _done; }

  void  next();

};

// ========================= SuperWord =====================

// -----------------------------SWNodeInfo---------------------------------

// Per node info needed by SuperWord

class SWNodeInfo {

 public:

  int         _alignment; // memory alignment for a node

  int         _depth;     // Max expression (DAG) depth from block start

  const Type* _velt_type; // vector element type

  Node_List*  _my_pack;   // pack containing this node

  SWNodeInfo() : _alignment(-1), _depth(0), _velt_type(NULL), _my_pack(NULL) {}

  static const SWNodeInfo initial;

};

class SuperWord;

class CMoveKit {

 friend class SuperWord;

 private:

  SuperWord* _sw;

  Dict* _dict;

  CMoveKit(Arena* a, SuperWord* sw) : _sw(sw)  {_dict = new Dict(cmpkey, hashkey, a);}

  void*     _2p(Node* key)        const  { return (void*)(intptr_t)key; } // 2 conversion functions to make gcc happy

  Dict*     dict()                const  { return _dict; }

  void map(Node* key, Node_List* val)    { assert(_dict->operator[](_2p(key)) == NULL, "key existed"); _dict->Insert(_2p(key), (void*)val); }

  void unmap(Node* key)                  { _dict->Delete(_2p(key)); }

  Node_List* pack(Node* key)      const  { return (Node_List*)_dict->operator[](_2p(key)); }

  Node* is_Bool_candidate(Node* nd) const; // if it is the right candidate return corresponding CMove* ,

  Node* is_CmpD_candidate(Node* nd) const; // otherwise return NULL

  Node_List* make_cmovevd_pack(Node_List* cmovd_pk);

  bool test_cmpd_pack(Node_List* cmpd_pk, Node_List* cmovd_pk);

};//class CMoveKit

// JVMCI: OrderedPair is moved up to deal with compilation issues on Windows

//------------------------------OrderedPair---------------------------

// Ordered pair of Node*.

class OrderedPair {

 protected:

  Node* _p1;

  Node* _p2;

 public:

  OrderedPair() : _p1(NULL), _p2(NULL) {}

  OrderedPair(Node* p1, Node* p2) {

    if (p1->_idx < p2->_idx) {

      _p1 = p1; _p2 = p2;

    } else {

      _p1 = p2; _p2 = p1;

    }

  }

  bool operator==(const OrderedPair &rhs) {

    return _p1 == rhs._p1 && _p2 == rhs._p2;

  }

  void print() { tty->print("  (%d, %d)", _p1->_idx, _p2->_idx); }

  static const OrderedPair initial;

};

// -----------------------------SuperWord---------------------------------

// Transforms scalar operations into packed (superword) operations.

class SuperWord : public ResourceObj {

 friend class SWPointer;

 friend class CMoveKit;

 private:

  PhaseIdealLoop* _phase;

  Arena*          _arena;

  PhaseIterGVN   &_igvn;

  enum consts { top_align = -1, bottom_align = -666 };

  GrowableArray<Node_List*> _packset;    // Packs for the current block

  GrowableArray<int> _bb_idx;            // Map from Node _idx to index within block

  GrowableArray<Node*> _block;           // Nodes in current block

  GrowableArray<Node*> _post_block;      // Nodes in post loop block

  GrowableArray<Node*> _data_entry;      // Nodes with all inputs from outside

  GrowableArray<Node*> _mem_slice_head;  // Memory slice head nodes

  GrowableArray<Node*> _mem_slice_tail;  // Memory slice tail nodes

  GrowableArray<Node*> _iteration_first; // nodes in the generation that has deps from phi

  GrowableArray<Node*> _iteration_last;  // nodes in the generation that has deps to   phi

  GrowableArray<SWNodeInfo> _node_info;  // Info needed per node

  CloneMap&            _clone_map;       // map of nodes created in cloning

  CMoveKit             _cmovev_kit;      // support for vectorization of CMov

  MemNode* _align_to_ref;                // Memory reference that pre-loop will align to

  GrowableArray<OrderedPair> _disjoint_ptrs; // runtime disambiguated pointer pairs

  DepGraph _dg; // Dependence graph

  // Scratch pads

  VectorSet    _visited;       // Visited set

  VectorSet    _post_visited;  // Post-visited set

  Node_Stack   _n_idx_list;    // List of (node,index) pairs

  GrowableArray<Node*> _nlist; // List of nodes

  GrowableArray<Node*> _stk;   // Stack of nodes

 public:

  SuperWord(PhaseIdealLoop* phase);

  void transform_loop(IdealLoopTree* lpt, bool do_optimization);

  void unrolling_analysis(int &local_loop_unroll_factor);

  // Accessors for SWPointer

  PhaseIdealLoop* phase()          { return _phase; }

  IdealLoopTree* lpt()             { return _lpt; }

  PhiNode* iv()                    { return _iv; }

  bool early_return()              { return _early_return; }

#ifndef PRODUCT

  bool     is_debug()              { return _vector_loop_debug > 0; }

  bool     is_trace_alignment()    { return (_vector_loop_debug & 2) > 0; }

  bool     is_trace_mem_slice()    { return (_vector_loop_debug & 4) > 0; }

  bool     is_trace_loop()         { return (_vector_loop_debug & 8) > 0; }

  bool     is_trace_adjacent()     { return (_vector_loop_debug & 16) > 0; }

  bool     is_trace_cmov()         { return (_vector_loop_debug & 32) > 0; }

  bool     is_trace_loop_reverse() { return (_vector_loop_debug & 64) > 0; }

#endif

  bool     do_vector_loop()        { return _do_vector_loop; }

  bool     do_reserve_copy()       { return _do_reserve_copy; }

 private:

  IdealLoopTree* _lpt;             // Current loop tree node

  LoopNode*      _lp;              // Current LoopNode

  Node*          _bb;              // Current basic block

  PhiNode*       _iv;              // Induction var

  bool           _race_possible;   // In cases where SDMU is true

  bool           _early_return;    // True if we do not initialize

  bool           _do_vector_loop;  // whether to do vectorization/simd style

  bool           _do_reserve_copy; // do reserve copy of the graph(loop) before final modification in output

  int            _num_work_vecs;   // Number of non memory vector operations

  int            _num_reductions;  // Number of reduction expressions applied

  int            _ii_first;        // generation with direct deps from mem phi

  int            _ii_last;         // generation with direct deps to   mem phi

  GrowableArray<int> _ii_order;

#ifndef PRODUCT

  uintx          _vector_loop_debug; // provide more printing in debug mode

#endif

  // Accessors

  Arena* arena()                   { return _arena; }

  Node* bb()                       { return _bb; }

  void  set_bb(Node* bb)           { _bb = bb; }

  void set_lpt(IdealLoopTree* lpt) { _lpt = lpt; }

  LoopNode* lp()                   { return _lp; }

  void      set_lp(LoopNode* lp)   { _lp = lp;

                                     _iv = lp->as_CountedLoop()->phi()->as_Phi(); }

  int      iv_stride()             { return lp()->as_CountedLoop()->stride_con(); }

  int vector_width(Node* n) {

    BasicType bt = velt_basic_type(n);

    return MIN2(ABS(iv_stride()), Matcher::max_vector_size(bt));

  }

  int vector_width_in_bytes(Node* n) {

    BasicType bt = velt_basic_type(n);

    return vector_width(n)*type2aelembytes(bt);

  }

  int get_vw_bytes_special(MemNode* s);

  MemNode* align_to_ref()            { return _align_to_ref; }

  void  set_align_to_ref(MemNode* m) { _align_to_ref = m; }

  Node* ctrl(Node* n) const { return _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; }

  // block accessors

  bool in_bb(Node* n)      { return n != NULL && n->outcnt() > 0 && ctrl(n) == _bb; }

  int  bb_idx(Node* n)     { assert(in_bb(n), "must be"); return _bb_idx.at(n->_idx); }

  void set_bb_idx(Node* n, int i) { _bb_idx.at_put_grow(n->_idx, i); }

  // visited set accessors

  void visited_clear()           { _visited.Clear(); }

  void visited_set(Node* n)      { return _visited.set(bb_idx(n)); }

  int visited_test(Node* n)      { return _visited.test(bb_idx(n)); }

  int visited_test_set(Node* n)  { return _visited.test_set(bb_idx(n)); }

  void post_visited_clear()      { _post_visited.Clear(); }

  void post_visited_set(Node* n) { return _post_visited.set(bb_idx(n)); }

  int post_visited_test(Node* n) { return _post_visited.test(bb_idx(n)); }

  // Ensure node_info contains element "i"

  void grow_node_info(int i) { if (i >= _node_info.length()) _node_info.at_put_grow(i, SWNodeInfo::initial); }

  // memory alignment for a node

  int alignment(Node* n)                     { return _node_info.adr_at(bb_idx(n))->_alignment; }

  void set_alignment(Node* n, int a)         { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_alignment = a; }

  // Max expression (DAG) depth from beginning of the block for each node

  int depth(Node* n)                         { return _node_info.adr_at(bb_idx(n))->_depth; }

  void set_depth(Node* n, int d)             { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_depth = d; }

  // vector element type

  const Type* velt_type(Node* n)             { return _node_info.adr_at(bb_idx(n))->_velt_type; }

  BasicType velt_basic_type(Node* n)         { return velt_type(n)->array_element_basic_type(); }

  void set_velt_type(Node* n, const Type* t) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_velt_type = t; }

  bool same_velt_type(Node* n1, Node* n2);

  // my_pack

  Node_List* my_pack(Node* n)                 { return !in_bb(n) ? NULL : _node_info.adr_at(bb_idx(n))->_my_pack; }

  void set_my_pack(Node* n, Node_List* p)     { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_my_pack = p; }

  // is pack good for converting into one vector node replacing 12 nodes of Cmp, Bool, CMov

  bool is_cmov_pack(Node_List* p);

  bool is_cmov_pack_internal_node(Node_List* p, Node* nd) { return is_cmov_pack(p) && !nd->is_CMove(); }

  // For pack p, are all idx operands the same?

  bool same_inputs(Node_List* p, int idx);

  // CloneMap utilities

  bool same_origin_idx(Node* a, Node* b) const;

  bool same_generation(Node* a, Node* b) const;

  // methods

  // Extract the superword level parallelism

  void SLP_extract();

  // Find the adjacent memory references and create pack pairs for them.

  void find_adjacent_refs();

  // Tracing support

  #ifndef PRODUCT

  void find_adjacent_refs_trace_1(Node* best_align_to_mem_ref, int best_iv_adjustment);

  void print_loop(bool whole);

  #endif

  // Find a memory reference to align the loop induction variable to.

  MemNode* find_align_to_ref(Node_List &memops);

  // Calculate loop's iv adjustment for this memory ops.

  int get_iv_adjustment(MemNode* mem);

  // Can the preloop align the reference to position zero in the vector?

  bool ref_is_alignable(SWPointer& p);

  // rebuild the graph so all loads in different iterations of cloned loop become dependant on phi node (in _do_vector_loop only)

  bool hoist_loads_in_graph();

  // Test whether MemNode::Memory dependency to the same load but in the first iteration of this loop is coming from memory phi

  // Return false if failed

  Node* find_phi_for_mem_dep(LoadNode* ld);

  // Return same node but from the first generation. Return 0, if not found

  Node* first_node(Node* nd);

  // Return same node as this but from the last generation. Return 0, if not found

  Node* last_node(Node* n);

  // Mark nodes belonging to first and last generation

  // returns first generation index or -1 if vectorization/simd is impossible

  int mark_generations();

  // swapping inputs of commutative instruction (Add or Mul)

  bool fix_commutative_inputs(Node* gold, Node* fix);

  // make packs forcefully (in _do_vector_loop only)

  bool pack_parallel();

  // Construct dependency graph.

  void dependence_graph();

  // Return a memory slice (node list) in predecessor order starting at "start"

  void mem_slice_preds(Node* start, Node* stop, GrowableArray<Node*> &preds);

  // Can s1 and s2 be in a pack with s1 immediately preceding s2 and  s1 aligned at "align"

  bool stmts_can_pack(Node* s1, Node* s2, int align);

  // Does s exist in a pack at position pos?

  bool exists_at(Node* s, uint pos);

  // Is s1 immediately before s2 in memory?

  bool are_adjacent_refs(Node* s1, Node* s2);

  // Are s1 and s2 similar?

  bool isomorphic(Node* s1, Node* s2);

  // Is there no data path from s1 to s2 or s2 to s1?

  bool independent(Node* s1, Node* s2);

  // For a node pair (s1, s2) which is isomorphic and independent,

  // do s1 and s2 have similar input edges?

  bool have_similar_inputs(Node* s1, Node* s2);

  // Is there a data path between s1 and s2 and both are reductions?

  bool reduction(Node* s1, Node* s2);

  // Helper for independent

  bool independent_path(Node* shallow, Node* deep, uint dp=0);

  void set_alignment(Node* s1, Node* s2, int align);

  int data_size(Node* s);

  // Extend packset by following use->def and def->use links from pack members.

  void extend_packlist();

  // Extend the packset by visiting operand definitions of nodes in pack p

  bool follow_use_defs(Node_List* p);

  // Extend the packset by visiting uses of nodes in pack p

  bool follow_def_uses(Node_List* p);

  // For extended packsets, ordinally arrange uses packset by major component

  void order_def_uses(Node_List* p);

  // Estimate the savings from executing s1 and s2 as a pack

  int est_savings(Node* s1, Node* s2);

  int adjacent_profit(Node* s1, Node* s2);

  int pack_cost(int ct);

  int unpack_cost(int ct);

  // Combine packs A and B with A.last == B.first into A.first..,A.last,B.second,..B.last

  void combine_packs();

  // Construct the map from nodes to packs.

  void construct_my_pack_map();

  // Remove packs that are not implemented or not profitable.

  void filter_packs();

  // Merge CMoveD into new vector-nodes

  void merge_packs_to_cmovd();

  // Adjust the memory graph for the packed operations

  void schedule();

  // Remove "current" from its current position in the memory graph and insert

  // it after the appropriate insert points (lip or uip);

  void remove_and_insert(MemNode *current, MemNode *prev, MemNode *lip, Node *uip, Unique_Node_List &schd_before);

  // Within a store pack, schedule stores together by moving out the sandwiched memory ops according

  // to dependence info; and within a load pack, move loads down to the last executed load.

  void co_locate_pack(Node_List* p);

  // Convert packs into vector node operations

  void output();

  // Create a vector operand for the nodes in pack p for operand: in(opd_idx)

  Node* vector_opd(Node_List* p, int opd_idx);

  // Can code be generated for pack p?

  bool implemented(Node_List* p);

  // For pack p, are all operands and all uses (with in the block) vector?

  bool profitable(Node_List* p);

  // If a use of pack p is not a vector use, then replace the use with an extract operation.

  void insert_extracts(Node_List* p);

  // Is use->in(u_idx) a vector use?

  bool is_vector_use(Node* use, int u_idx);

  // Construct reverse postorder list of block members

  bool construct_bb();

  // Initialize per node info

  void initialize_bb();

  // Insert n into block after pos

  void bb_insert_after(Node* n, int pos);

  // Compute max depth for expressions from beginning of block

  void compute_max_depth();

  // Compute necessary vector element type for expressions

  void compute_vector_element_type();

  // Are s1 and s2 in a pack pair and ordered as s1,s2?

  bool in_packset(Node* s1, Node* s2);

  // Is s in pack p?

  Node_List* in_pack(Node* s, Node_List* p);

  // Remove the pack at position pos in the packset

  void remove_pack_at(int pos);

  // Return the node executed first in pack p.