1 /*
   2  * Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "compiler/compileLog.hpp"
  26 #include "libadt/vectset.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "opto/addnode.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/divnode.hpp"
  31 #include "opto/matcher.hpp"
  32 #include "opto/memnode.hpp"
  33 #include "opto/mulnode.hpp"
  34 #include "opto/opcodes.hpp"
  35 #include "opto/superword.hpp"
  36 #include "opto/vectornode.hpp"
  37 
  38 //
  39 //                  S U P E R W O R D   T R A N S F O R M
  40 //=============================================================================
  41 
  42 //------------------------------SuperWord---------------------------
  43 SuperWord::SuperWord(PhaseIdealLoop* phase) :
  44   _phase(phase),
  45   _igvn(phase->_igvn),
  46   _arena(phase->C->comp_arena()),
  47   _packset(arena(), 8,  0, NULL),         // packs for the current block
  48   _bb_idx(arena(), (int)(1.10 * phase->C->unique()), 0, 0), // node idx to index in bb
  49   _block(arena(), 8,  0, NULL),           // nodes in current block
  50   _data_entry(arena(), 8,  0, NULL),      // nodes with all inputs from outside
  51   _mem_slice_head(arena(), 8,  0, NULL),  // memory slice heads
  52   _mem_slice_tail(arena(), 8,  0, NULL),  // memory slice tails
  53   _node_info(arena(), 8,  0, SWNodeInfo::initial), // info needed per node
  54   _align_to_ref(NULL),                    // memory reference to align vectors to
  55   _disjoint_ptrs(arena(), 8,  0, OrderedPair::initial), // runtime disambiguated pointer pairs
  56   _dg(_arena),                            // dependence graph
  57   _visited(arena()),                      // visited node set
  58   _post_visited(arena()),                 // post visited node set
  59   _n_idx_list(arena(), 8),                // scratch list of (node,index) pairs
  60   _stk(arena(), 8, 0, NULL),              // scratch stack of nodes
  61   _nlist(arena(), 8, 0, NULL),            // scratch list of nodes
  62   _lpt(NULL),                             // loop tree node
  63   _lp(NULL),                              // LoopNode
  64   _bb(NULL),                              // basic block
  65   _iv(NULL)                               // induction var
  66 {}
  67 
  68 //------------------------------transform_loop---------------------------
  69 void SuperWord::transform_loop(IdealLoopTree* lpt) {
  70   assert(UseSuperWord, "should be");
  71   // Do vectors exist on this architecture?
  72   if (Matcher::vector_width_in_bytes(T_BYTE) < 2) return;
  73 
  74   assert(lpt->_head->is_CountedLoop(), "must be");
  75   CountedLoopNode *cl = lpt->_head->as_CountedLoop();
  76 
  77   if (!cl->is_valid_counted_loop()) return; // skip malformed counted loop
  78 
  79   if (!cl->is_main_loop() ) return; // skip normal, pre, and post loops
  80 
  81   // Check for no control flow in body (other than exit)
  82   Node *cl_exit = cl->loopexit();
  83   if (cl_exit->in(0) != lpt->_head) return;
  84 
  85   // Make sure the are no extra control users of the loop backedge
  86   if (cl->back_control()->outcnt() != 1) {
  87     return;
  88   }
  89 
  90   // Check for pre-loop ending with CountedLoopEnd(Bool(Cmp(x,Opaque1(limit))))
  91   CountedLoopEndNode* pre_end = get_pre_loop_end(cl);
  92   if (pre_end == NULL) return;
  93   Node *pre_opaq1 = pre_end->limit();
  94   if (pre_opaq1->Opcode() != Op_Opaque1) return;
  95 
  96   init(); // initialize data structures
  97 
  98   set_lpt(lpt);
  99   set_lp(cl);
 100 
 101   // For now, define one block which is the entire loop body
 102   set_bb(cl);
 103 
 104   assert(_packset.length() == 0, "packset must be empty");
 105   SLP_extract();
 106 }
 107 
 108 //------------------------------SLP_extract---------------------------
 109 // Extract the superword level parallelism
 110 //
 111 // 1) A reverse post-order of nodes in the block is constructed.  By scanning
 112 //    this list from first to last, all definitions are visited before their uses.
 113 //
 114 // 2) A point-to-point dependence graph is constructed between memory references.
 115 //    This simplies the upcoming "independence" checker.
 116 //
 117 // 3) The maximum depth in the node graph from the beginning of the block
 118 //    to each node is computed.  This is used to prune the graph search
 119 //    in the independence checker.
 120 //
 121 // 4) For integer types, the necessary bit width is propagated backwards
 122 //    from stores to allow packed operations on byte, char, and short
 123 //    integers.  This reverses the promotion to type "int" that javac
 124 //    did for operations like: char c1,c2,c3;  c1 = c2 + c3.
 125 //
 126 // 5) One of the memory references is picked to be an aligned vector reference.
 127 //    The pre-loop trip count is adjusted to align this reference in the
 128 //    unrolled body.
 129 //
 130 // 6) The initial set of pack pairs is seeded with memory references.
 131 //
 132 // 7) The set of pack pairs is extended by following use->def and def->use links.
 133 //
 134 // 8) The pairs are combined into vector sized packs.
 135 //
 136 // 9) Reorder the memory slices to co-locate members of the memory packs.
 137 //
 138 // 10) Generate ideal vector nodes for the final set of packs and where necessary,
 139 //    inserting scalar promotion, vector creation from multiple scalars, and
 140 //    extraction of scalar values from vectors.
 141 //
 142 void SuperWord::SLP_extract() {
 143 
 144   // Ready the block
 145 
 146   construct_bb();
 147 
 148   dependence_graph();
 149 
 150   compute_max_depth();
 151 
 152   compute_vector_element_type();
 153 
 154   // Attempt vectorization
 155 
 156   find_adjacent_refs();
 157 
 158   extend_packlist();
 159 
 160   combine_packs();
 161 
 162   construct_my_pack_map();
 163 
 164   filter_packs();
 165 
 166   schedule();
 167 
 168   output();
 169 }
 170 
 171 //------------------------------find_adjacent_refs---------------------------
 172 // Find the adjacent memory references and create pack pairs for them.
 173 // This is the initial set of packs that will then be extended by
 174 // following use->def and def->use links.  The align positions are
 175 // assigned relative to the reference "align_to_ref"
 176 void SuperWord::find_adjacent_refs() {
 177   // Get list of memory operations
 178   Node_List memops;
 179   for (int i = 0; i < _block.length(); i++) {
 180     Node* n = _block.at(i);
 181     if (n->is_Mem() && !n->is_LoadStore() && in_bb(n) &&
 182         n->Opcode() != Op_LoadUI2L &&
 183         is_java_primitive(n->as_Mem()->memory_type())) {
 184       int align = memory_alignment(n->as_Mem(), 0);
 185       if (align != bottom_align) {
 186         memops.push(n);
 187       }
 188     }
 189   }
 190 
 191   Node_List align_to_refs;
 192   int best_iv_adjustment = 0;
 193   MemNode* best_align_to_mem_ref = NULL;
 194 
 195   while (memops.size() != 0) {
 196     // Find a memory reference to align to.
 197     MemNode* mem_ref = find_align_to_ref(memops);
 198     if (mem_ref == NULL) break;
 199     align_to_refs.push(mem_ref);
 200     int iv_adjustment = get_iv_adjustment(mem_ref);
 201 
 202     if (best_align_to_mem_ref == NULL) {
 203       // Set memory reference which is the best from all memory operations
 204       // to be used for alignment. The pre-loop trip count is modified to align
 205       // this reference to a vector-aligned address.
 206       best_align_to_mem_ref = mem_ref;
 207       best_iv_adjustment = iv_adjustment;
 208     }
 209 
 210     SWPointer align_to_ref_p(mem_ref, this);
 211     // Set alignment relative to "align_to_ref" for all related memory operations.
 212     for (int i = memops.size() - 1; i >= 0; i--) {
 213       MemNode* s = memops.at(i)->as_Mem();
 214       if (isomorphic(s, mem_ref)) {
 215         SWPointer p2(s, this);
 216         if (p2.comparable(align_to_ref_p)) {
 217           int align = memory_alignment(s, iv_adjustment);
 218           set_alignment(s, align);
 219         }
 220       }
 221     }
 222 
 223     // Create initial pack pairs of memory operations for which
 224     // alignment is set and vectors will be aligned.
 225     bool create_pack = true;
 226     if (memory_alignment(mem_ref, best_iv_adjustment) == 0) {
 227       if (!Matcher::misaligned_vectors_ok()) {
 228         int vw = vector_width(mem_ref);
 229         int vw_best = vector_width(best_align_to_mem_ref);
 230         if (vw > vw_best) {
 231           // Do not vectorize a memory access with more elements per vector
 232           // if unaligned memory access is not allowed because number of
 233           // iterations in pre-loop will be not enough to align it.
 234           create_pack = false;
 235         }
 236       }
 237     } else {
 238       if (same_velt_type(mem_ref, best_align_to_mem_ref)) {
 239         // Can't allow vectorization of unaligned memory accesses with the
 240         // same type since it could be overlapped accesses to the same array.
 241         create_pack = false;
 242       } else {
 243         // Allow independent (different type) unaligned memory operations
 244         // if HW supports them.
 245         if (!Matcher::misaligned_vectors_ok()) {
 246           create_pack = false;
 247         } else {
 248           // Check if packs of the same memory type but
 249           // with a different alignment were created before.
 250           for (uint i = 0; i < align_to_refs.size(); i++) {
 251             MemNode* mr = align_to_refs.at(i)->as_Mem();
 252             if (same_velt_type(mr, mem_ref) &&
 253                 memory_alignment(mr, iv_adjustment) != 0)
 254               create_pack = false;
 255           }
 256         }
 257       }
 258     }
 259     if (create_pack) {
 260       for (uint i = 0; i < memops.size(); i++) {
 261         Node* s1 = memops.at(i);
 262         int align = alignment(s1);
 263         if (align == top_align) continue;
 264         for (uint j = 0; j < memops.size(); j++) {
 265           Node* s2 = memops.at(j);
 266           if (alignment(s2) == top_align) continue;
 267           if (s1 != s2 && are_adjacent_refs(s1, s2)) {
 268             if (stmts_can_pack(s1, s2, align)) {
 269               Node_List* pair = new Node_List();
 270               pair->push(s1);
 271               pair->push(s2);
 272               _packset.append(pair);
 273             }
 274           }
 275         }
 276       }
 277     } else { // Don't create unaligned pack
 278       // First, remove remaining memory ops of the same type from the list.
 279       for (int i = memops.size() - 1; i >= 0; i--) {
 280         MemNode* s = memops.at(i)->as_Mem();
 281         if (same_velt_type(s, mem_ref)) {
 282           memops.remove(i);
 283         }
 284       }
 285 
 286       // Second, remove already constructed packs of the same type.
 287       for (int i = _packset.length() - 1; i >= 0; i--) {
 288         Node_List* p = _packset.at(i);
 289         MemNode* s = p->at(0)->as_Mem();
 290         if (same_velt_type(s, mem_ref)) {
 291           remove_pack_at(i);
 292         }
 293       }
 294 
 295       // If needed find the best memory reference for loop alignment again.
 296       if (same_velt_type(mem_ref, best_align_to_mem_ref)) {
 297         // Put memory ops from remaining packs back on memops list for
 298         // the best alignment search.
 299         uint orig_msize = memops.size();
 300         for (int i = 0; i < _packset.length(); i++) {
 301           Node_List* p = _packset.at(i);
 302           MemNode* s = p->at(0)->as_Mem();
 303           assert(!same_velt_type(s, mem_ref), "sanity");
 304           memops.push(s);
 305         }
 306         MemNode* best_align_to_mem_ref = find_align_to_ref(memops);
 307         if (best_align_to_mem_ref == NULL) break;
 308         best_iv_adjustment = get_iv_adjustment(best_align_to_mem_ref);
 309         // Restore list.
 310         while (memops.size() > orig_msize)
 311           (void)memops.pop();
 312       }
 313     } // unaligned memory accesses
 314 
 315     // Remove used mem nodes.
 316     for (int i = memops.size() - 1; i >= 0; i--) {
 317       MemNode* m = memops.at(i)->as_Mem();
 318       if (alignment(m) != top_align) {
 319         memops.remove(i);
 320       }
 321     }
 322 
 323   } // while (memops.size() != 0
 324   set_align_to_ref(best_align_to_mem_ref);
 325 
 326 #ifndef PRODUCT
 327   if (TraceSuperWord) {
 328     tty->print_cr("\nAfter find_adjacent_refs");
 329     print_packset();
 330   }
 331 #endif
 332 }
 333 
 334 //------------------------------find_align_to_ref---------------------------
 335 // Find a memory reference to align the loop induction variable to.
 336 // Looks first at stores then at loads, looking for a memory reference
 337 // with the largest number of references similar to it.
 338 MemNode* SuperWord::find_align_to_ref(Node_List &memops) {
 339   GrowableArray<int> cmp_ct(arena(), memops.size(), memops.size(), 0);
 340 
 341   // Count number of comparable memory ops
 342   for (uint i = 0; i < memops.size(); i++) {
 343     MemNode* s1 = memops.at(i)->as_Mem();
 344     SWPointer p1(s1, this);
 345     // Discard if pre loop can't align this reference
 346     if (!ref_is_alignable(p1)) {
 347       *cmp_ct.adr_at(i) = 0;
 348       continue;
 349     }
 350     for (uint j = i+1; j < memops.size(); j++) {
 351       MemNode* s2 = memops.at(j)->as_Mem();
 352       if (isomorphic(s1, s2)) {
 353         SWPointer p2(s2, this);
 354         if (p1.comparable(p2)) {
 355           (*cmp_ct.adr_at(i))++;
 356           (*cmp_ct.adr_at(j))++;
 357         }
 358       }
 359     }
 360   }
 361 
 362   // Find Store (or Load) with the greatest number of "comparable" references,
 363   // biggest vector size, smallest data size and smallest iv offset.
 364   int max_ct        = 0;
 365   int max_vw        = 0;
 366   int max_idx       = -1;
 367   int min_size      = max_jint;
 368   int min_iv_offset = max_jint;
 369   for (uint j = 0; j < memops.size(); j++) {
 370     MemNode* s = memops.at(j)->as_Mem();
 371     if (s->is_Store()) {
 372       int vw = vector_width_in_bytes(s);
 373       assert(vw > 1, "sanity");
 374       SWPointer p(s, this);
 375       if (cmp_ct.at(j) >  max_ct ||
 376           cmp_ct.at(j) == max_ct &&
 377             (vw >  max_vw ||
 378              vw == max_vw &&
 379               (data_size(s) <  min_size ||
 380                data_size(s) == min_size &&
 381                  (p.offset_in_bytes() < min_iv_offset)))) {
 382         max_ct = cmp_ct.at(j);
 383         max_vw = vw;
 384         max_idx = j;
 385         min_size = data_size(s);
 386         min_iv_offset = p.offset_in_bytes();
 387       }
 388     }
 389   }
 390   // If no stores, look at loads
 391   if (max_ct == 0) {
 392     for (uint j = 0; j < memops.size(); j++) {
 393       MemNode* s = memops.at(j)->as_Mem();
 394       if (s->is_Load()) {
 395         int vw = vector_width_in_bytes(s);
 396         assert(vw > 1, "sanity");
 397         SWPointer p(s, this);
 398         if (cmp_ct.at(j) >  max_ct ||
 399             cmp_ct.at(j) == max_ct &&
 400               (vw >  max_vw ||
 401                vw == max_vw &&
 402                 (data_size(s) <  min_size ||
 403                  data_size(s) == min_size &&
 404                    (p.offset_in_bytes() < min_iv_offset)))) {
 405           max_ct = cmp_ct.at(j);
 406           max_vw = vw;
 407           max_idx = j;
 408           min_size = data_size(s);
 409           min_iv_offset = p.offset_in_bytes();
 410         }
 411       }
 412     }
 413   }
 414 
 415 #ifdef ASSERT
 416   if (TraceSuperWord && Verbose) {
 417     tty->print_cr("\nVector memops after find_align_to_refs");
 418     for (uint i = 0; i < memops.size(); i++) {
 419       MemNode* s = memops.at(i)->as_Mem();
 420       s->dump();
 421     }
 422   }
 423 #endif
 424 
 425   if (max_ct > 0) {
 426 #ifdef ASSERT
 427     if (TraceSuperWord) {
 428       tty->print("\nVector align to node: ");
 429       memops.at(max_idx)->as_Mem()->dump();
 430     }
 431 #endif
 432     return memops.at(max_idx)->as_Mem();
 433   }
 434   return NULL;
 435 }
 436 
 437 //------------------------------ref_is_alignable---------------------------
 438 // Can the preloop align the reference to position zero in the vector?
 439 bool SuperWord::ref_is_alignable(SWPointer& p) {
 440   if (!p.has_iv()) {
 441     return true;   // no induction variable
 442   }
 443   CountedLoopEndNode* pre_end = get_pre_loop_end(lp()->as_CountedLoop());
 444   assert(pre_end->stride_is_con(), "pre loop stride is constant");
 445   int preloop_stride = pre_end->stride_con();
 446 
 447   int span = preloop_stride * p.scale_in_bytes();
 448 
 449   // Stride one accesses are alignable.
 450   if (ABS(span) == p.memory_size())
 451     return true;
 452 
 453   // If initial offset from start of object is computable,
 454   // compute alignment within the vector.
 455   int vw = vector_width_in_bytes(p.mem());
 456   assert(vw > 1, "sanity");
 457   if (vw % span == 0) {
 458     Node* init_nd = pre_end->init_trip();
 459     if (init_nd->is_Con() && p.invar() == NULL) {
 460       int init = init_nd->bottom_type()->is_int()->get_con();
 461 
 462       int init_offset = init * p.scale_in_bytes() + p.offset_in_bytes();
 463       assert(init_offset >= 0, "positive offset from object start");
 464 
 465       if (span > 0) {
 466         return (vw - (init_offset % vw)) % span == 0;
 467       } else {
 468         assert(span < 0, "nonzero stride * scale");
 469         return (init_offset % vw) % -span == 0;
 470       }
 471     }
 472   }
 473   return false;
 474 }
 475 
 476 //---------------------------get_iv_adjustment---------------------------
 477 // Calculate loop's iv adjustment for this memory ops.
 478 int SuperWord::get_iv_adjustment(MemNode* mem_ref) {
 479   SWPointer align_to_ref_p(mem_ref, this);
 480   int offset = align_to_ref_p.offset_in_bytes();
 481   int scale  = align_to_ref_p.scale_in_bytes();
 482   int vw       = vector_width_in_bytes(mem_ref);
 483   assert(vw > 1, "sanity");
 484   int stride_sign   = (scale * iv_stride()) > 0 ? 1 : -1;
 485   // At least one iteration is executed in pre-loop by default. As result
 486   // several iterations are needed to align memory operations in main-loop even
 487   // if offset is 0.
 488   int iv_adjustment_in_bytes = (stride_sign * vw - (offset % vw));
 489   int elt_size = align_to_ref_p.memory_size();
 490   assert(((ABS(iv_adjustment_in_bytes) % elt_size) == 0),
 491          err_msg_res("(%d) should be divisible by (%d)", iv_adjustment_in_bytes, elt_size));
 492   int iv_adjustment = iv_adjustment_in_bytes/elt_size;
 493 
 494 #ifndef PRODUCT
 495   if (TraceSuperWord)
 496     tty->print_cr("\noffset = %d iv_adjust = %d elt_size = %d scale = %d iv_stride = %d vect_size %d",
 497                   offset, iv_adjustment, elt_size, scale, iv_stride(), vw);
 498 #endif
 499   return iv_adjustment;
 500 }
 501 
 502 //---------------------------dependence_graph---------------------------
 503 // Construct dependency graph.
 504 // Add dependence edges to load/store nodes for memory dependence
 505 //    A.out()->DependNode.in(1) and DependNode.out()->B.prec(x)
 506 void SuperWord::dependence_graph() {
 507   // First, assign a dependence node to each memory node
 508   for (int i = 0; i < _block.length(); i++ ) {
 509     Node *n = _block.at(i);
 510     if (n->is_Mem() || n->is_Phi() && n->bottom_type() == Type::MEMORY) {
 511       _dg.make_node(n);
 512     }
 513   }
 514 
 515   // For each memory slice, create the dependences
 516   for (int i = 0; i < _mem_slice_head.length(); i++) {
 517     Node* n      = _mem_slice_head.at(i);
 518     Node* n_tail = _mem_slice_tail.at(i);
 519 
 520     // Get slice in predecessor order (last is first)
 521     mem_slice_preds(n_tail, n, _nlist);
 522 
 523     // Make the slice dependent on the root
 524     DepMem* slice = _dg.dep(n);
 525     _dg.make_edge(_dg.root(), slice);
 526 
 527     // Create a sink for the slice
 528     DepMem* slice_sink = _dg.make_node(NULL);
 529     _dg.make_edge(slice_sink, _dg.tail());
 530 
 531     // Now visit each pair of memory ops, creating the edges
 532     for (int j = _nlist.length() - 1; j >= 0 ; j--) {
 533       Node* s1 = _nlist.at(j);
 534 
 535       // If no dependency yet, use slice
 536       if (_dg.dep(s1)->in_cnt() == 0) {
 537         _dg.make_edge(slice, s1);
 538       }
 539       SWPointer p1(s1->as_Mem(), this);
 540       bool sink_dependent = true;
 541       for (int k = j - 1; k >= 0; k--) {
 542         Node* s2 = _nlist.at(k);
 543         if (s1->is_Load() && s2->is_Load())
 544           continue;
 545         SWPointer p2(s2->as_Mem(), this);
 546 
 547         int cmp = p1.cmp(p2);
 548         if (SuperWordRTDepCheck &&
 549             p1.base() != p2.base() && p1.valid() && p2.valid()) {
 550           // Create a runtime check to disambiguate
 551           OrderedPair pp(p1.base(), p2.base());
 552           _disjoint_ptrs.append_if_missing(pp);
 553         } else if (!SWPointer::not_equal(cmp)) {
 554           // Possibly same address
 555           _dg.make_edge(s1, s2);
 556           sink_dependent = false;
 557         }
 558       }
 559       if (sink_dependent) {
 560         _dg.make_edge(s1, slice_sink);
 561       }
 562     }
 563 #ifndef PRODUCT
 564     if (TraceSuperWord) {
 565       tty->print_cr("\nDependence graph for slice: %d", n->_idx);
 566       for (int q = 0; q < _nlist.length(); q++) {
 567         _dg.print(_nlist.at(q));
 568       }
 569       tty->cr();
 570     }
 571 #endif
 572     _nlist.clear();
 573   }
 574 
 575 #ifndef PRODUCT
 576   if (TraceSuperWord) {
 577     tty->print_cr("\ndisjoint_ptrs: %s", _disjoint_ptrs.length() > 0 ? "" : "NONE");
 578     for (int r = 0; r < _disjoint_ptrs.length(); r++) {
 579       _disjoint_ptrs.at(r).print();
 580       tty->cr();
 581     }
 582     tty->cr();
 583   }
 584 #endif
 585 }
 586 
 587 //---------------------------mem_slice_preds---------------------------
 588 // Return a memory slice (node list) in predecessor order starting at "start"
 589 void SuperWord::mem_slice_preds(Node* start, Node* stop, GrowableArray<Node*> &preds) {
 590   assert(preds.length() == 0, "start empty");
 591   Node* n = start;
 592   Node* prev = NULL;
 593   while (true) {
 594     assert(in_bb(n), "must be in block");
 595     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 596       Node* out = n->fast_out(i);
 597       if (out->is_Load()) {
 598         if (in_bb(out)) {
 599           preds.push(out);
 600         }
 601       } else {
 602         // FIXME
 603         if (out->is_MergeMem() && !in_bb(out)) {
 604           // Either unrolling is causing a memory edge not to disappear,
 605           // or need to run igvn.optimize() again before SLP
 606         } else if (out->is_Phi() && out->bottom_type() == Type::MEMORY && !in_bb(out)) {
 607           // Ditto.  Not sure what else to check further.
 608         } else if (out->Opcode() == Op_StoreCM && out->in(MemNode::OopStore) == n) {
 609           // StoreCM has an input edge used as a precedence edge.
 610           // Maybe an issue when oop stores are vectorized.
 611         } else {
 612           assert(out == prev || prev == NULL, "no branches off of store slice");
 613         }
 614       }
 615     }
 616     if (n == stop) break;
 617     preds.push(n);
 618     prev = n;
 619     n = n->in(MemNode::Memory);
 620   }
 621 }
 622 
 623 //------------------------------stmts_can_pack---------------------------
 624 // Can s1 and s2 be in a pack with s1 immediately preceding s2 and
 625 // s1 aligned at "align"
 626 bool SuperWord::stmts_can_pack(Node* s1, Node* s2, int align) {
 627 
 628   // Do not use superword for non-primitives
 629   BasicType bt1 = velt_basic_type(s1);
 630   BasicType bt2 = velt_basic_type(s2);
 631   if(!is_java_primitive(bt1) || !is_java_primitive(bt2))
 632     return false;
 633   if (Matcher::max_vector_size(bt1) < 2) {
 634     return false; // No vectors for this type
 635   }
 636 
 637   if (isomorphic(s1, s2)) {
 638     if (independent(s1, s2)) {
 639       if (!exists_at(s1, 0) && !exists_at(s2, 1)) {
 640         if (!s1->is_Mem() || are_adjacent_refs(s1, s2)) {
 641           int s1_align = alignment(s1);
 642           int s2_align = alignment(s2);
 643           if (s1_align == top_align || s1_align == align) {
 644             if (s2_align == top_align || s2_align == align + data_size(s1)) {
 645               return true;
 646             }
 647           }
 648         }
 649       }
 650     }
 651   }
 652   return false;
 653 }
 654 
 655 //------------------------------exists_at---------------------------
 656 // Does s exist in a pack at position pos?
 657 bool SuperWord::exists_at(Node* s, uint pos) {
 658   for (int i = 0; i < _packset.length(); i++) {
 659     Node_List* p = _packset.at(i);
 660     if (p->at(pos) == s) {
 661       return true;
 662     }
 663   }
 664   return false;
 665 }
 666 
 667 //------------------------------are_adjacent_refs---------------------------
 668 // Is s1 immediately before s2 in memory?
 669 bool SuperWord::are_adjacent_refs(Node* s1, Node* s2) {
 670   if (!s1->is_Mem() || !s2->is_Mem()) return false;
 671   if (!in_bb(s1)    || !in_bb(s2))    return false;
 672 
 673   // Do not use superword for non-primitives
 674   if (!is_java_primitive(s1->as_Mem()->memory_type()) ||
 675       !is_java_primitive(s2->as_Mem()->memory_type())) {
 676     return false;
 677   }
 678 
 679   // FIXME - co_locate_pack fails on Stores in different mem-slices, so
 680   // only pack memops that are in the same alias set until that's fixed.
 681   if (_phase->C->get_alias_index(s1->as_Mem()->adr_type()) !=
 682       _phase->C->get_alias_index(s2->as_Mem()->adr_type()))
 683     return false;
 684   SWPointer p1(s1->as_Mem(), this);
 685   SWPointer p2(s2->as_Mem(), this);
 686   if (p1.base() != p2.base() || !p1.comparable(p2)) return false;
 687   int diff = p2.offset_in_bytes() - p1.offset_in_bytes();
 688   return diff == data_size(s1);
 689 }
 690 
 691 //------------------------------isomorphic---------------------------
 692 // Are s1 and s2 similar?
 693 bool SuperWord::isomorphic(Node* s1, Node* s2) {
 694   if (s1->Opcode() != s2->Opcode()) return false;
 695   if (s1->req() != s2->req()) return false;
 696   if (s1->in(0) != s2->in(0)) return false;
 697   if (!same_velt_type(s1, s2)) return false;
 698   return true;
 699 }
 700 
 701 //------------------------------independent---------------------------
 702 // Is there no data path from s1 to s2 or s2 to s1?
 703 bool SuperWord::independent(Node* s1, Node* s2) {
 704   //  assert(s1->Opcode() == s2->Opcode(), "check isomorphic first");
 705   int d1 = depth(s1);
 706   int d2 = depth(s2);
 707   if (d1 == d2) return s1 != s2;
 708   Node* deep    = d1 > d2 ? s1 : s2;
 709   Node* shallow = d1 > d2 ? s2 : s1;
 710 
 711   visited_clear();
 712 
 713   return independent_path(shallow, deep);
 714 }
 715 
 716 //------------------------------independent_path------------------------------
 717 // Helper for independent
 718 bool SuperWord::independent_path(Node* shallow, Node* deep, uint dp) {
 719   if (dp >= 1000) return false; // stop deep recursion
 720   visited_set(deep);
 721   int shal_depth = depth(shallow);
 722   assert(shal_depth <= depth(deep), "must be");
 723   for (DepPreds preds(deep, _dg); !preds.done(); preds.next()) {
 724     Node* pred = preds.current();
 725     if (in_bb(pred) && !visited_test(pred)) {
 726       if (shallow == pred) {
 727         return false;
 728       }
 729       if (shal_depth < depth(pred) && !independent_path(shallow, pred, dp+1)) {
 730         return false;
 731       }
 732     }
 733   }
 734   return true;
 735 }
 736 
 737 //------------------------------set_alignment---------------------------
 738 void SuperWord::set_alignment(Node* s1, Node* s2, int align) {
 739   set_alignment(s1, align);
 740   if (align == top_align || align == bottom_align) {
 741     set_alignment(s2, align);
 742   } else {
 743     set_alignment(s2, align + data_size(s1));
 744   }
 745 }
 746 
 747 //------------------------------data_size---------------------------
 748 int SuperWord::data_size(Node* s) {
 749   int bsize = type2aelembytes(velt_basic_type(s));
 750   assert(bsize != 0, "valid size");
 751   return bsize;
 752 }
 753 
 754 //------------------------------extend_packlist---------------------------
 755 // Extend packset by following use->def and def->use links from pack members.
 756 void SuperWord::extend_packlist() {
 757   bool changed;
 758   do {
 759     changed = false;
 760     for (int i = 0; i < _packset.length(); i++) {
 761       Node_List* p = _packset.at(i);
 762       changed |= follow_use_defs(p);
 763       changed |= follow_def_uses(p);
 764     }
 765   } while (changed);
 766 
 767 #ifndef PRODUCT
 768   if (TraceSuperWord) {
 769     tty->print_cr("\nAfter extend_packlist");
 770     print_packset();
 771   }
 772 #endif
 773 }
 774 
 775 //------------------------------follow_use_defs---------------------------
 776 // Extend the packset by visiting operand definitions of nodes in pack p
 777 bool SuperWord::follow_use_defs(Node_List* p) {
 778   assert(p->size() == 2, "just checking");
 779   Node* s1 = p->at(0);
 780   Node* s2 = p->at(1);
 781   assert(s1->req() == s2->req(), "just checking");
 782   assert(alignment(s1) + data_size(s1) == alignment(s2), "just checking");
 783 
 784   if (s1->is_Load()) return false;
 785 
 786   int align = alignment(s1);
 787   bool changed = false;
 788   int start = s1->is_Store() ? MemNode::ValueIn   : 1;
 789   int end   = s1->is_Store() ? MemNode::ValueIn+1 : s1->req();
 790   for (int j = start; j < end; j++) {
 791     Node* t1 = s1->in(j);
 792     Node* t2 = s2->in(j);
 793     if (!in_bb(t1) || !in_bb(t2))
 794       continue;
 795     if (stmts_can_pack(t1, t2, align)) {
 796       if (est_savings(t1, t2) >= 0) {
 797         Node_List* pair = new Node_List();
 798         pair->push(t1);
 799         pair->push(t2);
 800         _packset.append(pair);
 801         set_alignment(t1, t2, align);
 802         changed = true;
 803       }
 804     }
 805   }
 806   return changed;
 807 }
 808 
 809 //------------------------------follow_def_uses---------------------------
 810 // Extend the packset by visiting uses of nodes in pack p
 811 bool SuperWord::follow_def_uses(Node_List* p) {
 812   bool changed = false;
 813   Node* s1 = p->at(0);
 814   Node* s2 = p->at(1);
 815   assert(p->size() == 2, "just checking");
 816   assert(s1->req() == s2->req(), "just checking");
 817   assert(alignment(s1) + data_size(s1) == alignment(s2), "just checking");
 818 
 819   if (s1->is_Store()) return false;
 820 
 821   int align = alignment(s1);
 822   int savings = -1;
 823   Node* u1 = NULL;
 824   Node* u2 = NULL;
 825   for (DUIterator_Fast imax, i = s1->fast_outs(imax); i < imax; i++) {
 826     Node* t1 = s1->fast_out(i);
 827     if (!in_bb(t1)) continue;
 828     for (DUIterator_Fast jmax, j = s2->fast_outs(jmax); j < jmax; j++) {
 829       Node* t2 = s2->fast_out(j);
 830       if (!in_bb(t2)) continue;
 831       if (!opnd_positions_match(s1, t1, s2, t2))
 832         continue;
 833       if (stmts_can_pack(t1, t2, align)) {
 834         int my_savings = est_savings(t1, t2);
 835         if (my_savings > savings) {
 836           savings = my_savings;
 837           u1 = t1;
 838           u2 = t2;
 839         }
 840       }
 841     }
 842   }
 843   if (savings >= 0) {
 844     Node_List* pair = new Node_List();
 845     pair->push(u1);
 846     pair->push(u2);
 847     _packset.append(pair);
 848     set_alignment(u1, u2, align);
 849     changed = true;
 850   }
 851   return changed;
 852 }
 853 
 854 //---------------------------opnd_positions_match-------------------------
 855 // Is the use of d1 in u1 at the same operand position as d2 in u2?
 856 bool SuperWord::opnd_positions_match(Node* d1, Node* u1, Node* d2, Node* u2) {
 857   uint ct = u1->req();
 858   if (ct != u2->req()) return false;
 859   uint i1 = 0;
 860   uint i2 = 0;
 861   do {
 862     for (i1++; i1 < ct; i1++) if (u1->in(i1) == d1) break;
 863     for (i2++; i2 < ct; i2++) if (u2->in(i2) == d2) break;
 864     if (i1 != i2) {
 865       if ((i1 == (3-i2)) && (u2->is_Add() || u2->is_Mul())) {
 866         // Further analysis relies on operands position matching.
 867         u2->swap_edges(i1, i2);
 868       } else {
 869         return false;
 870       }
 871     }
 872   } while (i1 < ct);
 873   return true;
 874 }
 875 
 876 //------------------------------est_savings---------------------------
 877 // Estimate the savings from executing s1 and s2 as a pack
 878 int SuperWord::est_savings(Node* s1, Node* s2) {
 879   int save_in = 2 - 1; // 2 operations per instruction in packed form
 880 
 881   // inputs
 882   for (uint i = 1; i < s1->req(); i++) {
 883     Node* x1 = s1->in(i);
 884     Node* x2 = s2->in(i);
 885     if (x1 != x2) {
 886       if (are_adjacent_refs(x1, x2)) {
 887         save_in += adjacent_profit(x1, x2);
 888       } else if (!in_packset(x1, x2)) {
 889         save_in -= pack_cost(2);
 890       } else {
 891         save_in += unpack_cost(2);
 892       }
 893     }
 894   }
 895 
 896   // uses of result
 897   uint ct = 0;
 898   int save_use = 0;
 899   for (DUIterator_Fast imax, i = s1->fast_outs(imax); i < imax; i++) {
 900     Node* s1_use = s1->fast_out(i);
 901     for (int j = 0; j < _packset.length(); j++) {
 902       Node_List* p = _packset.at(j);
 903       if (p->at(0) == s1_use) {
 904         for (DUIterator_Fast kmax, k = s2->fast_outs(kmax); k < kmax; k++) {
 905           Node* s2_use = s2->fast_out(k);
 906           if (p->at(p->size()-1) == s2_use) {
 907             ct++;
 908             if (are_adjacent_refs(s1_use, s2_use)) {
 909               save_use += adjacent_profit(s1_use, s2_use);
 910             }
 911           }
 912         }
 913       }
 914     }
 915   }
 916 
 917   if (ct < s1->outcnt()) save_use += unpack_cost(1);
 918   if (ct < s2->outcnt()) save_use += unpack_cost(1);
 919 
 920   return MAX2(save_in, save_use);
 921 }
 922 
 923 //------------------------------costs---------------------------
 924 int SuperWord::adjacent_profit(Node* s1, Node* s2) { return 2; }
 925 int SuperWord::pack_cost(int ct)   { return ct; }
 926 int SuperWord::unpack_cost(int ct) { return ct; }
 927 
 928 //------------------------------combine_packs---------------------------
 929 // Combine packs A and B with A.last == B.first into A.first..,A.last,B.second,..B.last
 930 void SuperWord::combine_packs() {
 931   bool changed = true;
 932   // Combine packs regardless max vector size.
 933   while (changed) {
 934     changed = false;
 935     for (int i = 0; i < _packset.length(); i++) {
 936       Node_List* p1 = _packset.at(i);
 937       if (p1 == NULL) continue;
 938       for (int j = 0; j < _packset.length(); j++) {
 939         Node_List* p2 = _packset.at(j);
 940         if (p2 == NULL) continue;
 941         if (i == j) continue;
 942         if (p1->at(p1->size()-1) == p2->at(0)) {
 943           for (uint k = 1; k < p2->size(); k++) {
 944             p1->push(p2->at(k));
 945           }
 946           _packset.at_put(j, NULL);
 947           changed = true;
 948         }
 949       }
 950     }
 951   }
 952 
 953   // Split packs which have size greater then max vector size.
 954   for (int i = 0; i < _packset.length(); i++) {
 955     Node_List* p1 = _packset.at(i);
 956     if (p1 != NULL) {
 957       BasicType bt = velt_basic_type(p1->at(0));
 958       uint max_vlen = Matcher::max_vector_size(bt); // Max elements in vector
 959       assert(is_power_of_2(max_vlen), "sanity");
 960       uint psize = p1->size();
 961       if (!is_power_of_2(psize)) {
 962         // Skip pack which can't be vector.
 963         // case1: for(...) { a[i] = i; }    elements values are different (i+x)
 964         // case2: for(...) { a[i] = b[i+1]; }  can't align both, load and store
 965         _packset.at_put(i, NULL);
 966         continue;
 967       }
 968       if (psize > max_vlen) {
 969         Node_List* pack = new Node_List();
 970         for (uint j = 0; j < psize; j++) {
 971           pack->push(p1->at(j));
 972           if (pack->size() >= max_vlen) {
 973             assert(is_power_of_2(pack->size()), "sanity");
 974             _packset.append(pack);
 975             pack = new Node_List();
 976           }
 977         }
 978         _packset.at_put(i, NULL);
 979       }
 980     }
 981   }
 982 
 983   // Compress list.
 984   for (int i = _packset.length() - 1; i >= 0; i--) {
 985     Node_List* p1 = _packset.at(i);
 986     if (p1 == NULL) {
 987       _packset.remove_at(i);
 988     }
 989   }
 990 
 991 #ifndef PRODUCT
 992   if (TraceSuperWord) {
 993     tty->print_cr("\nAfter combine_packs");
 994     print_packset();
 995   }
 996 #endif
 997 }
 998 
 999 //-----------------------------construct_my_pack_map--------------------------
1000 // Construct the map from nodes to packs.  Only valid after the
1001 // point where a node is only in one pack (after combine_packs).
1002 void SuperWord::construct_my_pack_map() {
1003   Node_List* rslt = NULL;
1004   for (int i = 0; i < _packset.length(); i++) {
1005     Node_List* p = _packset.at(i);
1006     for (uint j = 0; j < p->size(); j++) {
1007       Node* s = p->at(j);
1008       assert(my_pack(s) == NULL, "only in one pack");
1009       set_my_pack(s, p);
1010     }
1011   }
1012 }
1013 
1014 //------------------------------filter_packs---------------------------
1015 // Remove packs that are not implemented or not profitable.
1016 void SuperWord::filter_packs() {
1017 
1018   // Remove packs that are not implemented
1019   for (int i = _packset.length() - 1; i >= 0; i--) {
1020     Node_List* pk = _packset.at(i);
1021     bool impl = implemented(pk);
1022     if (!impl) {
1023 #ifndef PRODUCT
1024       if (TraceSuperWord && Verbose) {
1025         tty->print_cr("Unimplemented");
1026         pk->at(0)->dump();
1027       }
1028 #endif
1029       remove_pack_at(i);
1030     }
1031   }
1032 
1033   // Remove packs that are not profitable
1034   bool changed;
1035   do {
1036     changed = false;
1037     for (int i = _packset.length() - 1; i >= 0; i--) {
1038       Node_List* pk = _packset.at(i);
1039       bool prof = profitable(pk);
1040       if (!prof) {
1041 #ifndef PRODUCT
1042         if (TraceSuperWord && Verbose) {
1043           tty->print_cr("Unprofitable");
1044           pk->at(0)->dump();
1045         }
1046 #endif
1047         remove_pack_at(i);
1048         changed = true;
1049       }
1050     }
1051   } while (changed);
1052 
1053 #ifndef PRODUCT
1054   if (TraceSuperWord) {
1055     tty->print_cr("\nAfter filter_packs");
1056     print_packset();
1057     tty->cr();
1058   }
1059 #endif
1060 }
1061 
1062 //------------------------------implemented---------------------------
1063 // Can code be generated for pack p?
1064 bool SuperWord::implemented(Node_List* p) {
1065   Node* p0 = p->at(0);
1066   return VectorNode::implemented(p0->Opcode(), p->size(), velt_basic_type(p0));
1067 }
1068 
1069 //------------------------------same_inputs--------------------------
1070 // For pack p, are all idx operands the same?
1071 static bool same_inputs(Node_List* p, int idx) {
1072   Node* p0 = p->at(0);
1073   uint vlen = p->size();
1074   Node* p0_def = p0->in(idx);
1075   for (uint i = 1; i < vlen; i++) {
1076     Node* pi = p->at(i);
1077     Node* pi_def = pi->in(idx);
1078     if (p0_def != pi_def)
1079       return false;
1080   }
1081   return true;
1082 }
1083 
1084 //------------------------------profitable---------------------------
1085 // For pack p, are all operands and all uses (with in the block) vector?
1086 bool SuperWord::profitable(Node_List* p) {
1087   Node* p0 = p->at(0);
1088   uint start, end;
1089   VectorNode::vector_operands(p0, &start, &end);
1090 
1091   // Return false if some inputs are not vectors or vectors with different
1092   // size or alignment.
1093   // Also, for now, return false if not scalar promotion case when inputs are
1094   // the same. Later, implement PackNode and allow differing, non-vector inputs
1095   // (maybe just the ones from outside the block.)
1096   for (uint i = start; i < end; i++) {
1097     if (!is_vector_use(p0, i))
1098       return false;
1099   }
1100   if (VectorNode::is_shift(p0)) {
1101     // For now, return false if shift count is vector or not scalar promotion
1102     // case (different shift counts) because it is not supported yet.
1103     Node* cnt = p0->in(2);
1104     Node_List* cnt_pk = my_pack(cnt);
1105     if (cnt_pk != NULL)
1106       return false;
1107     if (!same_inputs(p, 2))
1108       return false;
1109   }
1110   if (!p0->is_Store()) {
1111     // For now, return false if not all uses are vector.
1112     // Later, implement ExtractNode and allow non-vector uses (maybe
1113     // just the ones outside the block.)
1114     for (uint i = 0; i < p->size(); i++) {
1115       Node* def = p->at(i);
1116       for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
1117         Node* use = def->fast_out(j);
1118         for (uint k = 0; k < use->req(); k++) {
1119           Node* n = use->in(k);
1120           if (def == n) {
1121             if (!is_vector_use(use, k)) {
1122               return false;
1123             }
1124           }
1125         }
1126       }
1127     }
1128   }
1129   return true;
1130 }
1131 
1132 //------------------------------schedule---------------------------
1133 // Adjust the memory graph for the packed operations
1134 void SuperWord::schedule() {
1135 
1136   // Co-locate in the memory graph the members of each memory pack
1137   for (int i = 0; i < _packset.length(); i++) {
1138     co_locate_pack(_packset.at(i));
1139   }
1140 }
1141 
1142 //-------------------------------remove_and_insert-------------------
1143 // Remove "current" from its current position in the memory graph and insert
1144 // it after the appropriate insertion point (lip or uip).
1145 void SuperWord::remove_and_insert(MemNode *current, MemNode *prev, MemNode *lip,
1146                                   Node *uip, Unique_Node_List &sched_before) {
1147   Node* my_mem = current->in(MemNode::Memory);
1148   bool sched_up = sched_before.member(current);
1149 
1150   // remove current_store from its current position in the memmory graph
1151   for (DUIterator i = current->outs(); current->has_out(i); i++) {
1152     Node* use = current->out(i);
1153     if (use->is_Mem()) {
1154       assert(use->in(MemNode::Memory) == current, "must be");
1155       if (use == prev) { // connect prev to my_mem
1156           _igvn.replace_input_of(use, MemNode::Memory, my_mem);
1157           --i; //deleted this edge; rescan position
1158       } else if (sched_before.member(use)) {
1159         if (!sched_up) { // Will be moved together with current
1160           _igvn.replace_input_of(use, MemNode::Memory, uip);
1161           --i; //deleted this edge; rescan position
1162         }
1163       } else {
1164         if (sched_up) { // Will be moved together with current
1165           _igvn.replace_input_of(use, MemNode::Memory, lip);
1166           --i; //deleted this edge; rescan position
1167         }
1168       }
1169     }
1170   }
1171 
1172   Node *insert_pt =  sched_up ?  uip : lip;
1173 
1174   // all uses of insert_pt's memory state should use current's instead
1175   for (DUIterator i = insert_pt->outs(); insert_pt->has_out(i); i++) {
1176     Node* use = insert_pt->out(i);
1177     if (use->is_Mem()) {
1178       assert(use->in(MemNode::Memory) == insert_pt, "must be");
1179       _igvn.replace_input_of(use, MemNode::Memory, current);
1180       --i; //deleted this edge; rescan position
1181     } else if (!sched_up && use->is_Phi() && use->bottom_type() == Type::MEMORY) {
1182       uint pos; //lip (lower insert point) must be the last one in the memory slice
1183       for (pos=1; pos < use->req(); pos++) {
1184         if (use->in(pos) == insert_pt) break;
1185       }
1186       _igvn.replace_input_of(use, pos, current);
1187       --i;
1188     }
1189   }
1190 
1191   //connect current to insert_pt
1192   _igvn.replace_input_of(current, MemNode::Memory, insert_pt);
1193 }
1194 
1195 //------------------------------co_locate_pack----------------------------------
1196 // To schedule a store pack, we need to move any sandwiched memory ops either before
1197 // or after the pack, based upon dependence information:
1198 // (1) If any store in the pack depends on the sandwiched memory op, the
1199 //     sandwiched memory op must be scheduled BEFORE the pack;
1200 // (2) If a sandwiched memory op depends on any store in the pack, the
1201 //     sandwiched memory op must be scheduled AFTER the pack;
1202 // (3) If a sandwiched memory op (say, memA) depends on another sandwiched
1203 //     memory op (say memB), memB must be scheduled before memA. So, if memA is
1204 //     scheduled before the pack, memB must also be scheduled before the pack;
1205 // (4) If there is no dependence restriction for a sandwiched memory op, we simply
1206 //     schedule this store AFTER the pack
1207 // (5) We know there is no dependence cycle, so there in no other case;
1208 // (6) Finally, all memory ops in another single pack should be moved in the same direction.
1209 //
1210 // To schedule a load pack, we use the memory state of either the first or the last load in
1211 // the pack, based on the dependence constraint.
1212 void SuperWord::co_locate_pack(Node_List* pk) {
1213   if (pk->at(0)->is_Store()) {
1214     MemNode* first     = executed_first(pk)->as_Mem();
1215     MemNode* last      = executed_last(pk)->as_Mem();
1216     Unique_Node_List schedule_before_pack;
1217     Unique_Node_List memops;
1218 
1219     MemNode* current   = last->in(MemNode::Memory)->as_Mem();
1220     MemNode* previous  = last;
1221     while (true) {
1222       assert(in_bb(current), "stay in block");
1223       memops.push(previous);
1224       for (DUIterator i = current->outs(); current->has_out(i); i++) {
1225         Node* use = current->out(i);
1226         if (use->is_Mem() && use != previous)
1227           memops.push(use);
1228       }
1229       if (current == first) break;
1230       previous = current;
1231       current  = current->in(MemNode::Memory)->as_Mem();
1232     }
1233 
1234     // determine which memory operations should be scheduled before the pack
1235     for (uint i = 1; i < memops.size(); i++) {
1236       Node *s1 = memops.at(i);
1237       if (!in_pack(s1, pk) && !schedule_before_pack.member(s1)) {
1238         for (uint j = 0; j< i; j++) {
1239           Node *s2 = memops.at(j);
1240           if (!independent(s1, s2)) {
1241             if (in_pack(s2, pk) || schedule_before_pack.member(s2)) {
1242               schedule_before_pack.push(s1); // s1 must be scheduled before
1243               Node_List* mem_pk = my_pack(s1);
1244               if (mem_pk != NULL) {
1245                 for (uint ii = 0; ii < mem_pk->size(); ii++) {
1246                   Node* s = mem_pk->at(ii);  // follow partner
1247                   if (memops.member(s) && !schedule_before_pack.member(s))
1248                     schedule_before_pack.push(s);
1249                 }
1250               }
1251               break;
1252             }
1253           }
1254         }
1255       }
1256     }
1257 
1258     Node*    upper_insert_pt = first->in(MemNode::Memory);
1259     // Following code moves loads connected to upper_insert_pt below aliased stores.
1260     // Collect such loads here and reconnect them back to upper_insert_pt later.
1261     memops.clear();
1262     for (DUIterator i = upper_insert_pt->outs(); upper_insert_pt->has_out(i); i++) {
1263       Node* use = upper_insert_pt->out(i);
1264       if (!use->is_Store())
1265         memops.push(use);
1266     }
1267 
1268     MemNode* lower_insert_pt = last;
1269     previous                 = last; //previous store in pk
1270     current                  = last->in(MemNode::Memory)->as_Mem();
1271 
1272     // start scheduling from "last" to "first"
1273     while (true) {
1274       assert(in_bb(current), "stay in block");
1275       assert(in_pack(previous, pk), "previous stays in pack");
1276       Node* my_mem = current->in(MemNode::Memory);
1277 
1278       if (in_pack(current, pk)) {
1279         // Forward users of my memory state (except "previous) to my input memory state
1280         for (DUIterator i = current->outs(); current->has_out(i); i++) {
1281           Node* use = current->out(i);
1282           if (use->is_Mem() && use != previous) {
1283             assert(use->in(MemNode::Memory) == current, "must be");
1284             if (schedule_before_pack.member(use)) {
1285               _igvn.replace_input_of(use, MemNode::Memory, upper_insert_pt);
1286             } else {
1287               _igvn.replace_input_of(use, MemNode::Memory, lower_insert_pt);
1288             }
1289             --i; // deleted this edge; rescan position
1290           }
1291         }
1292         previous = current;
1293       } else { // !in_pack(current, pk) ==> a sandwiched store
1294         remove_and_insert(current, previous, lower_insert_pt, upper_insert_pt, schedule_before_pack);
1295       }
1296 
1297       if (current == first) break;
1298       current = my_mem->as_Mem();
1299     } // end while
1300 
1301     // Reconnect loads back to upper_insert_pt.
1302     for (uint i = 0; i < memops.size(); i++) {
1303       Node *ld = memops.at(i);
1304       if (ld->in(MemNode::Memory) != upper_insert_pt) {
1305         _igvn.replace_input_of(ld, MemNode::Memory, upper_insert_pt);
1306       }
1307     }
1308   } else if (pk->at(0)->is_Load()) { //load
1309     // all loads in the pack should have the same memory state. By default,
1310     // we use the memory state of the last load. However, if any load could
1311     // not be moved down due to the dependence constraint, we use the memory
1312     // state of the first load.
1313     Node* last_mem  = executed_last(pk)->in(MemNode::Memory);
1314     Node* first_mem = executed_first(pk)->in(MemNode::Memory);
1315     bool schedule_last = true;
1316     for (uint i = 0; i < pk->size(); i++) {
1317       Node* ld = pk->at(i);
1318       for (Node* current = last_mem; current != ld->in(MemNode::Memory);
1319            current=current->in(MemNode::Memory)) {
1320         assert(current != first_mem, "corrupted memory graph");
1321         if(current->is_Mem() && !independent(current, ld)){
1322           schedule_last = false; // a later store depends on this load
1323           break;
1324         }
1325       }
1326     }
1327 
1328     Node* mem_input = schedule_last ? last_mem : first_mem;
1329     _igvn.hash_delete(mem_input);
1330     // Give each load the same memory state
1331     for (uint i = 0; i < pk->size(); i++) {
1332       LoadNode* ld = pk->at(i)->as_Load();
1333       _igvn.replace_input_of(ld, MemNode::Memory, mem_input);
1334     }
1335   }
1336 }
1337 
1338 //------------------------------output---------------------------
1339 // Convert packs into vector node operations
1340 void SuperWord::output() {
1341   if (_packset.length() == 0) return;
1342 
1343 #ifndef PRODUCT
1344   if (TraceLoopOpts) {
1345     tty->print("SuperWord    ");
1346     lpt()->dump_head();
1347   }
1348 #endif
1349 
1350   // MUST ENSURE main loop's initial value is properly aligned:
1351   //  (iv_initial_value + min_iv_offset) % vector_width_in_bytes() == 0
1352 
1353   align_initial_loop_index(align_to_ref());
1354 
1355   // Insert extract (unpack) operations for scalar uses
1356   for (int i = 0; i < _packset.length(); i++) {
1357     insert_extracts(_packset.at(i));
1358   }
1359 
1360   Compile* C = _phase->C;
1361   uint max_vlen_in_bytes = 0;
1362   for (int i = 0; i < _block.length(); i++) {
1363     Node* n = _block.at(i);
1364     Node_List* p = my_pack(n);
1365     if (p && n == executed_last(p)) {
1366       uint vlen = p->size();
1367       uint vlen_in_bytes = 0;
1368       Node* vn = NULL;
1369       Node* low_adr = p->at(0);
1370       Node* first   = executed_first(p);
1371       int   opc = n->Opcode();
1372       if (n->is_Load()) {
1373         Node* ctl = n->in(MemNode::Control);
1374         Node* mem = first->in(MemNode::Memory);
1375         Node* adr = low_adr->in(MemNode::Address);
1376         const TypePtr* atyp = n->adr_type();
1377         vn = LoadVectorNode::make(C, opc, ctl, mem, adr, atyp, vlen, velt_basic_type(n));
1378         vlen_in_bytes = vn->as_LoadVector()->memory_size();
1379       } else if (n->is_Store()) {
1380         // Promote value to be stored to vector
1381         Node* val = vector_opd(p, MemNode::ValueIn);
1382         Node* ctl = n->in(MemNode::Control);
1383         Node* mem = first->in(MemNode::Memory);
1384         Node* adr = low_adr->in(MemNode::Address);
1385         const TypePtr* atyp = n->adr_type();
1386         vn = StoreVectorNode::make(C, opc, ctl, mem, adr, atyp, val, vlen);
1387         vlen_in_bytes = vn->as_StoreVector()->memory_size();
1388       } else if (n->req() == 3) {
1389         // Promote operands to vector
1390         Node* in1 = vector_opd(p, 1);
1391         Node* in2 = vector_opd(p, 2);
1392         if (VectorNode::is_invariant_vector(in1) && (n->is_Add() || n->is_Mul())) {
1393           // Move invariant vector input into second position to avoid register spilling.
1394           Node* tmp = in1;
1395           in1 = in2;
1396           in2 = tmp;
1397         }
1398         vn = VectorNode::make(C, opc, in1, in2, vlen, velt_basic_type(n));
1399         vlen_in_bytes = vn->as_Vector()->length_in_bytes();
1400       } else {
1401         ShouldNotReachHere();
1402       }
1403       assert(vn != NULL, "sanity");
1404       _igvn.register_new_node_with_optimizer(vn);
1405       _phase->set_ctrl(vn, _phase->get_ctrl(p->at(0)));
1406       for (uint j = 0; j < p->size(); j++) {
1407         Node* pm = p->at(j);
1408         _igvn.replace_node(pm, vn);
1409       }
1410       _igvn._worklist.push(vn);
1411 
1412       if (vlen_in_bytes > max_vlen_in_bytes) {
1413         max_vlen_in_bytes = vlen_in_bytes;
1414       }
1415 #ifdef ASSERT
1416       if (TraceNewVectors) {
1417         tty->print("new Vector node: ");
1418         vn->dump();
1419       }
1420 #endif
1421     }
1422   }
1423   C->set_max_vector_size(max_vlen_in_bytes);
1424 }
1425 
1426 //------------------------------vector_opd---------------------------
1427 // Create a vector operand for the nodes in pack p for operand: in(opd_idx)
1428 Node* SuperWord::vector_opd(Node_List* p, int opd_idx) {
1429   Node* p0 = p->at(0);
1430   uint vlen = p->size();
1431   Node* opd = p0->in(opd_idx);
1432 
1433   if (same_inputs(p, opd_idx)) {
1434     if (opd->is_Vector() || opd->is_LoadVector()) {
1435       assert(((opd_idx != 2) || !VectorNode::is_shift(p0)), "shift's count can't be vector");
1436       return opd; // input is matching vector
1437     }
1438     if ((opd_idx == 2) && VectorNode::is_shift(p0)) {
1439       Compile* C = _phase->C;
1440       Node* cnt = opd;
1441       // Vector instructions do not mask shift count, do it here.
1442       juint mask = (p0->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
1443       const TypeInt* t = opd->find_int_type();
1444       if (t != NULL && t->is_con()) {
1445         juint shift = t->get_con();
1446         if (shift > mask) { // Unsigned cmp
1447           cnt = ConNode::make(C, TypeInt::make(shift & mask));
1448         }
1449       } else {
1450         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
1451           cnt = ConNode::make(C, TypeInt::make(mask));
1452           _igvn.register_new_node_with_optimizer(cnt);
1453           cnt = new (C) AndINode(opd, cnt);
1454           _igvn.register_new_node_with_optimizer(cnt);
1455           _phase->set_ctrl(cnt, _phase->get_ctrl(opd));
1456         }
1457         assert(opd->bottom_type()->isa_int(), "int type only");
1458         // Move non constant shift count into vector register.
1459         cnt = VectorNode::shift_count(C, p0, cnt, vlen, velt_basic_type(p0));
1460       }
1461       if (cnt != opd) {
1462         _igvn.register_new_node_with_optimizer(cnt);
1463         _phase->set_ctrl(cnt, _phase->get_ctrl(opd));
1464       }
1465       return cnt;
1466     }
1467     assert(!opd->is_StoreVector(), "such vector is not expected here");
1468     // Convert scalar input to vector with the same number of elements as
1469     // p0's vector. Use p0's type because size of operand's container in
1470     // vector should match p0's size regardless operand's size.
1471     const Type* p0_t = velt_type(p0);
1472     VectorNode* vn = VectorNode::scalar2vector(_phase->C, opd, vlen, p0_t);
1473 
1474     _igvn.register_new_node_with_optimizer(vn);
1475     _phase->set_ctrl(vn, _phase->get_ctrl(opd));
1476 #ifdef ASSERT
1477     if (TraceNewVectors) {
1478       tty->print("new Vector node: ");
1479       vn->dump();
1480     }
1481 #endif
1482     return vn;
1483   }
1484 
1485   // Insert pack operation
1486   BasicType bt = velt_basic_type(p0);
1487   PackNode* pk = PackNode::make(_phase->C, opd, vlen, bt);
1488   DEBUG_ONLY( const BasicType opd_bt = opd->bottom_type()->basic_type(); )
1489 
1490   for (uint i = 1; i < vlen; i++) {
1491     Node* pi = p->at(i);
1492     Node* in = pi->in(opd_idx);
1493     assert(my_pack(in) == NULL, "Should already have been unpacked");
1494     assert(opd_bt == in->bottom_type()->basic_type(), "all same type");
1495     pk->add_opd(in);
1496   }
1497   _igvn.register_new_node_with_optimizer(pk);
1498   _phase->set_ctrl(pk, _phase->get_ctrl(opd));
1499 #ifdef ASSERT
1500   if (TraceNewVectors) {
1501     tty->print("new Vector node: ");
1502     pk->dump();
1503   }
1504 #endif
1505   return pk;
1506 }
1507 
1508 //------------------------------insert_extracts---------------------------
1509 // If a use of pack p is not a vector use, then replace the
1510 // use with an extract operation.
1511 void SuperWord::insert_extracts(Node_List* p) {
1512   if (p->at(0)->is_Store()) return;
1513   assert(_n_idx_list.is_empty(), "empty (node,index) list");
1514 
1515   // Inspect each use of each pack member.  For each use that is
1516   // not a vector use, replace the use with an extract operation.
1517 
1518   for (uint i = 0; i < p->size(); i++) {
1519     Node* def = p->at(i);
1520     for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
1521       Node* use = def->fast_out(j);
1522       for (uint k = 0; k < use->req(); k++) {
1523         Node* n = use->in(k);
1524         if (def == n) {
1525           if (!is_vector_use(use, k)) {
1526             _n_idx_list.push(use, k);
1527           }
1528         }
1529       }
1530     }
1531   }
1532 
1533   while (_n_idx_list.is_nonempty()) {
1534     Node* use = _n_idx_list.node();
1535     int   idx = _n_idx_list.index();
1536     _n_idx_list.pop();
1537     Node* def = use->in(idx);
1538 
1539     // Insert extract operation
1540     _igvn.hash_delete(def);
1541     int def_pos = alignment(def) / data_size(def);
1542 
1543     Node* ex = ExtractNode::make(_phase->C, def, def_pos, velt_basic_type(def));
1544     _igvn.register_new_node_with_optimizer(ex);
1545     _phase->set_ctrl(ex, _phase->get_ctrl(def));
1546     _igvn.replace_input_of(use, idx, ex);
1547     _igvn._worklist.push(def);
1548 
1549     bb_insert_after(ex, bb_idx(def));
1550     set_velt_type(ex, velt_type(def));
1551   }
1552 }
1553 
1554 //------------------------------is_vector_use---------------------------
1555 // Is use->in(u_idx) a vector use?
1556 bool SuperWord::is_vector_use(Node* use, int u_idx) {
1557   Node_List* u_pk = my_pack(use);
1558   if (u_pk == NULL) return false;
1559   Node* def = use->in(u_idx);
1560   Node_List* d_pk = my_pack(def);
1561   if (d_pk == NULL) {
1562     // check for scalar promotion
1563     Node* n = u_pk->at(0)->in(u_idx);
1564     for (uint i = 1; i < u_pk->size(); i++) {
1565       if (u_pk->at(i)->in(u_idx) != n) return false;
1566     }
1567     return true;
1568   }
1569   if (u_pk->size() != d_pk->size())
1570     return false;
1571   for (uint i = 0; i < u_pk->size(); i++) {
1572     Node* ui = u_pk->at(i);
1573     Node* di = d_pk->at(i);
1574     if (ui->in(u_idx) != di || alignment(ui) != alignment(di))
1575       return false;
1576   }
1577   return true;
1578 }
1579 
1580 //------------------------------construct_bb---------------------------
1581 // Construct reverse postorder list of block members
1582 void SuperWord::construct_bb() {
1583   Node* entry = bb();
1584 
1585   assert(_stk.length() == 0,            "stk is empty");
1586   assert(_block.length() == 0,          "block is empty");
1587   assert(_data_entry.length() == 0,     "data_entry is empty");
1588   assert(_mem_slice_head.length() == 0, "mem_slice_head is empty");
1589   assert(_mem_slice_tail.length() == 0, "mem_slice_tail is empty");
1590 
1591   // Find non-control nodes with no inputs from within block,
1592   // create a temporary map from node _idx to bb_idx for use
1593   // by the visited and post_visited sets,
1594   // and count number of nodes in block.
1595   int bb_ct = 0;
1596   for (uint i = 0; i < lpt()->_body.size(); i++ ) {
1597     Node *n = lpt()->_body.at(i);
1598     set_bb_idx(n, i); // Create a temporary map
1599     if (in_bb(n)) {
1600       bb_ct++;
1601       if (!n->is_CFG()) {
1602         bool found = false;
1603         for (uint j = 0; j < n->req(); j++) {
1604           Node* def = n->in(j);
1605           if (def && in_bb(def)) {
1606             found = true;
1607             break;
1608           }
1609         }
1610         if (!found) {
1611           assert(n != entry, "can't be entry");
1612           _data_entry.push(n);
1613         }
1614       }
1615     }
1616   }
1617 
1618   // Find memory slices (head and tail)
1619   for (DUIterator_Fast imax, i = lp()->fast_outs(imax); i < imax; i++) {
1620     Node *n = lp()->fast_out(i);
1621     if (in_bb(n) && (n->is_Phi() && n->bottom_type() == Type::MEMORY)) {
1622       Node* n_tail  = n->in(LoopNode::LoopBackControl);
1623       if (n_tail != n->in(LoopNode::EntryControl)) {
1624         _mem_slice_head.push(n);
1625         _mem_slice_tail.push(n_tail);
1626       }
1627     }
1628   }
1629 
1630   // Create an RPO list of nodes in block
1631 
1632   visited_clear();
1633   post_visited_clear();
1634 
1635   // Push all non-control nodes with no inputs from within block, then control entry
1636   for (int j = 0; j < _data_entry.length(); j++) {
1637     Node* n = _data_entry.at(j);
1638     visited_set(n);
1639     _stk.push(n);
1640   }
1641   visited_set(entry);
1642   _stk.push(entry);
1643 
1644   // Do a depth first walk over out edges
1645   int rpo_idx = bb_ct - 1;
1646   int size;
1647   while ((size = _stk.length()) > 0) {
1648     Node* n = _stk.top(); // Leave node on stack
1649     if (!visited_test_set(n)) {
1650       // forward arc in graph
1651     } else if (!post_visited_test(n)) {
1652       // cross or back arc
1653       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1654         Node *use = n->fast_out(i);
1655         if (in_bb(use) && !visited_test(use) &&
1656             // Don't go around backedge
1657             (!use->is_Phi() || n == entry)) {
1658           _stk.push(use);
1659         }
1660       }
1661       if (_stk.length() == size) {
1662         // There were no additional uses, post visit node now
1663         _stk.pop(); // Remove node from stack
1664         assert(rpo_idx >= 0, "");
1665         _block.at_put_grow(rpo_idx, n);
1666         rpo_idx--;
1667         post_visited_set(n);
1668         assert(rpo_idx >= 0 || _stk.is_empty(), "");
1669       }
1670     } else {
1671       _stk.pop(); // Remove post-visited node from stack
1672     }
1673   }
1674 
1675   // Create real map of block indices for nodes
1676   for (int j = 0; j < _block.length(); j++) {
1677     Node* n = _block.at(j);
1678     set_bb_idx(n, j);
1679   }
1680 
1681   initialize_bb(); // Ensure extra info is allocated.
1682 
1683 #ifndef PRODUCT
1684   if (TraceSuperWord) {
1685     print_bb();
1686     tty->print_cr("\ndata entry nodes: %s", _data_entry.length() > 0 ? "" : "NONE");
1687     for (int m = 0; m < _data_entry.length(); m++) {
1688       tty->print("%3d ", m);
1689       _data_entry.at(m)->dump();
1690     }
1691     tty->print_cr("\nmemory slices: %s", _mem_slice_head.length() > 0 ? "" : "NONE");
1692     for (int m = 0; m < _mem_slice_head.length(); m++) {
1693       tty->print("%3d ", m); _mem_slice_head.at(m)->dump();
1694       tty->print("    ");    _mem_slice_tail.at(m)->dump();
1695     }
1696   }
1697 #endif
1698   assert(rpo_idx == -1 && bb_ct == _block.length(), "all block members found");
1699 }
1700 
1701 //------------------------------initialize_bb---------------------------
1702 // Initialize per node info
1703 void SuperWord::initialize_bb() {
1704   Node* last = _block.at(_block.length() - 1);
1705   grow_node_info(bb_idx(last));
1706 }
1707 
1708 //------------------------------bb_insert_after---------------------------
1709 // Insert n into block after pos
1710 void SuperWord::bb_insert_after(Node* n, int pos) {
1711   int n_pos = pos + 1;
1712   // Make room
1713   for (int i = _block.length() - 1; i >= n_pos; i--) {
1714     _block.at_put_grow(i+1, _block.at(i));
1715   }
1716   for (int j = _node_info.length() - 1; j >= n_pos; j--) {
1717     _node_info.at_put_grow(j+1, _node_info.at(j));
1718   }
1719   // Set value
1720   _block.at_put_grow(n_pos, n);
1721   _node_info.at_put_grow(n_pos, SWNodeInfo::initial);
1722   // Adjust map from node->_idx to _block index
1723   for (int i = n_pos; i < _block.length(); i++) {
1724     set_bb_idx(_block.at(i), i);
1725   }
1726 }
1727 
1728 //------------------------------compute_max_depth---------------------------
1729 // Compute max depth for expressions from beginning of block
1730 // Use to prune search paths during test for independence.
1731 void SuperWord::compute_max_depth() {
1732   int ct = 0;
1733   bool again;
1734   do {
1735     again = false;
1736     for (int i = 0; i < _block.length(); i++) {
1737       Node* n = _block.at(i);
1738       if (!n->is_Phi()) {
1739         int d_orig = depth(n);
1740         int d_in   = 0;
1741         for (DepPreds preds(n, _dg); !preds.done(); preds.next()) {
1742           Node* pred = preds.current();
1743           if (in_bb(pred)) {
1744             d_in = MAX2(d_in, depth(pred));
1745           }
1746         }
1747         if (d_in + 1 != d_orig) {
1748           set_depth(n, d_in + 1);
1749           again = true;
1750         }
1751       }
1752     }
1753     ct++;
1754   } while (again);
1755 #ifndef PRODUCT
1756   if (TraceSuperWord && Verbose)
1757     tty->print_cr("compute_max_depth iterated: %d times", ct);
1758 #endif
1759 }
1760 
1761 //-------------------------compute_vector_element_type-----------------------
1762 // Compute necessary vector element type for expressions
1763 // This propagates backwards a narrower integer type when the
1764 // upper bits of the value are not needed.
1765 // Example:  char a,b,c;  a = b + c;
1766 // Normally the type of the add is integer, but for packed character
1767 // operations the type of the add needs to be char.
1768 void SuperWord::compute_vector_element_type() {
1769 #ifndef PRODUCT
1770   if (TraceSuperWord && Verbose)
1771     tty->print_cr("\ncompute_velt_type:");
1772 #endif
1773 
1774   // Initial type
1775   for (int i = 0; i < _block.length(); i++) {
1776     Node* n = _block.at(i);
1777     set_velt_type(n, container_type(n));
1778   }
1779 
1780   // Propagate narrowed type backwards through operations
1781   // that don't depend on higher order bits
1782   for (int i = _block.length() - 1; i >= 0; i--) {
1783     Node* n = _block.at(i);
1784     // Only integer types need be examined
1785     const Type* vt = velt_type(n);
1786     if (vt->basic_type() == T_INT) {
1787       uint start, end;
1788       VectorNode::vector_operands(n, &start, &end);
1789       const Type* vt = velt_type(n);
1790 
1791       for (uint j = start; j < end; j++) {
1792         Node* in  = n->in(j);
1793         // Don't propagate through a memory
1794         if (!in->is_Mem() && in_bb(in) && velt_type(in)->basic_type() == T_INT &&
1795             data_size(n) < data_size(in)) {
1796           bool same_type = true;
1797           for (DUIterator_Fast kmax, k = in->fast_outs(kmax); k < kmax; k++) {
1798             Node *use = in->fast_out(k);
1799             if (!in_bb(use) || !same_velt_type(use, n)) {
1800               same_type = false;
1801               break;
1802             }
1803           }
1804           if (same_type) {
1805             set_velt_type(in, vt);
1806           }
1807         }
1808       }
1809     }
1810   }
1811 #ifndef PRODUCT
1812   if (TraceSuperWord && Verbose) {
1813     for (int i = 0; i < _block.length(); i++) {
1814       Node* n = _block.at(i);
1815       velt_type(n)->dump();
1816       tty->print("\t");
1817       n->dump();
1818     }
1819   }
1820 #endif
1821 }
1822 
1823 //------------------------------memory_alignment---------------------------
1824 // Alignment within a vector memory reference
1825 int SuperWord::memory_alignment(MemNode* s, int iv_adjust) {
1826   SWPointer p(s, this);
1827   if (!p.valid()) {
1828     return bottom_align;
1829   }
1830   int vw = vector_width_in_bytes(s);
1831   if (vw < 2) {
1832     return bottom_align; // No vectors for this type
1833   }
1834   int offset  = p.offset_in_bytes();
1835   offset     += iv_adjust*p.memory_size();
1836   int off_rem = offset % vw;
1837   int off_mod = off_rem >= 0 ? off_rem : off_rem + vw;
1838   return off_mod;
1839 }
1840 
1841 //---------------------------container_type---------------------------
1842 // Smallest type containing range of values
1843 const Type* SuperWord::container_type(Node* n) {
1844   if (n->is_Mem()) {
1845     return Type::get_const_basic_type(n->as_Mem()->memory_type());
1846   }
1847   const Type* t = _igvn.type(n);
1848   if (t->basic_type() == T_INT) {
1849     // A narrow type of arithmetic operations will be determined by
1850     // propagating the type of memory operations.
1851     return TypeInt::INT;
1852   }
1853   return t;
1854 }
1855 
1856 bool SuperWord::same_velt_type(Node* n1, Node* n2) {
1857   const Type* vt1 = velt_type(n1);
1858   const Type* vt2 = velt_type(n2);
1859   if (vt1->basic_type() == T_INT && vt2->basic_type() == T_INT) {
1860     // Compare vectors element sizes for integer types.
1861     return data_size(n1) == data_size(n2);
1862   }
1863   return vt1 == vt2;
1864 }
1865 
1866 //------------------------------in_packset---------------------------
1867 // Are s1 and s2 in a pack pair and ordered as s1,s2?
1868 bool SuperWord::in_packset(Node* s1, Node* s2) {
1869   for (int i = 0; i < _packset.length(); i++) {
1870     Node_List* p = _packset.at(i);
1871     assert(p->size() == 2, "must be");
1872     if (p->at(0) == s1 && p->at(p->size()-1) == s2) {
1873       return true;
1874     }
1875   }
1876   return false;
1877 }
1878 
1879 //------------------------------in_pack---------------------------
1880 // Is s in pack p?
1881 Node_List* SuperWord::in_pack(Node* s, Node_List* p) {
1882   for (uint i = 0; i < p->size(); i++) {
1883     if (p->at(i) == s) {
1884       return p;
1885     }
1886   }
1887   return NULL;
1888 }
1889 
1890 //------------------------------remove_pack_at---------------------------
1891 // Remove the pack at position pos in the packset
1892 void SuperWord::remove_pack_at(int pos) {
1893   Node_List* p = _packset.at(pos);
1894   for (uint i = 0; i < p->size(); i++) {
1895     Node* s = p->at(i);
1896     set_my_pack(s, NULL);
1897   }
1898   _packset.remove_at(pos);
1899 }
1900 
1901 //------------------------------executed_first---------------------------
1902 // Return the node executed first in pack p.  Uses the RPO block list
1903 // to determine order.
1904 Node* SuperWord::executed_first(Node_List* p) {
1905   Node* n = p->at(0);
1906   int n_rpo = bb_idx(n);
1907   for (uint i = 1; i < p->size(); i++) {
1908     Node* s = p->at(i);
1909     int s_rpo = bb_idx(s);
1910     if (s_rpo < n_rpo) {
1911       n = s;
1912       n_rpo = s_rpo;
1913     }
1914   }
1915   return n;
1916 }
1917 
1918 //------------------------------executed_last---------------------------
1919 // Return the node executed last in pack p.
1920 Node* SuperWord::executed_last(Node_List* p) {
1921   Node* n = p->at(0);
1922   int n_rpo = bb_idx(n);
1923   for (uint i = 1; i < p->size(); i++) {
1924     Node* s = p->at(i);
1925     int s_rpo = bb_idx(s);
1926     if (s_rpo > n_rpo) {
1927       n = s;
1928       n_rpo = s_rpo;
1929     }
1930   }
1931   return n;
1932 }
1933 
1934 //----------------------------align_initial_loop_index---------------------------
1935 // Adjust pre-loop limit so that in main loop, a load/store reference
1936 // to align_to_ref will be a position zero in the vector.
1937 //   (iv + k) mod vector_align == 0
1938 void SuperWord::align_initial_loop_index(MemNode* align_to_ref) {
1939   CountedLoopNode *main_head = lp()->as_CountedLoop();
1940   assert(main_head->is_main_loop(), "");
1941   CountedLoopEndNode* pre_end = get_pre_loop_end(main_head);
1942   assert(pre_end != NULL, "");
1943   Node *pre_opaq1 = pre_end->limit();
1944   assert(pre_opaq1->Opcode() == Op_Opaque1, "");
1945   Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1;
1946   Node *lim0 = pre_opaq->in(1);
1947 
1948   // Where we put new limit calculations
1949   Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl);
1950 
1951   // Ensure the original loop limit is available from the
1952   // pre-loop Opaque1 node.
1953   Node *orig_limit = pre_opaq->original_loop_limit();
1954   assert(orig_limit != NULL && _igvn.type(orig_limit) != Type::TOP, "");
1955 
1956   SWPointer align_to_ref_p(align_to_ref, this);
1957   assert(align_to_ref_p.valid(), "sanity");
1958 
1959   // Given:
1960   //     lim0 == original pre loop limit
1961   //     V == v_align (power of 2)
1962   //     invar == extra invariant piece of the address expression
1963   //     e == offset [ +/- invar ]
1964   //
1965   // When reassociating expressions involving '%' the basic rules are:
1966   //     (a - b) % k == 0   =>  a % k == b % k
1967   // and:
1968   //     (a + b) % k == 0   =>  a % k == (k - b) % k
1969   //
1970   // For stride > 0 && scale > 0,
1971   //   Derive the new pre-loop limit "lim" such that the two constraints:
1972   //     (1) lim = lim0 + N           (where N is some positive integer < V)
1973   //     (2) (e + lim) % V == 0
1974   //   are true.
1975   //
1976   //   Substituting (1) into (2),
1977   //     (e + lim0 + N) % V == 0
1978   //   solve for N:
1979   //     N = (V - (e + lim0)) % V
1980   //   substitute back into (1), so that new limit
1981   //     lim = lim0 + (V - (e + lim0)) % V
1982   //
1983   // For stride > 0 && scale < 0
1984   //   Constraints:
1985   //     lim = lim0 + N
1986   //     (e - lim) % V == 0
1987   //   Solving for lim:
1988   //     (e - lim0 - N) % V == 0
1989   //     N = (e - lim0) % V
1990   //     lim = lim0 + (e - lim0) % V
1991   //
1992   // For stride < 0 && scale > 0
1993   //   Constraints:
1994   //     lim = lim0 - N
1995   //     (e + lim) % V == 0
1996   //   Solving for lim:
1997   //     (e + lim0 - N) % V == 0
1998   //     N = (e + lim0) % V
1999   //     lim = lim0 - (e + lim0) % V
2000   //
2001   // For stride < 0 && scale < 0
2002   //   Constraints:
2003   //     lim = lim0 - N
2004   //     (e - lim) % V == 0
2005   //   Solving for lim:
2006   //     (e - lim0 + N) % V == 0
2007   //     N = (V - (e - lim0)) % V
2008   //     lim = lim0 - (V - (e - lim0)) % V
2009 
2010   int vw = vector_width_in_bytes(align_to_ref);
2011   int stride   = iv_stride();
2012   int scale    = align_to_ref_p.scale_in_bytes();
2013   int elt_size = align_to_ref_p.memory_size();
2014   int v_align  = vw / elt_size;
2015   assert(v_align > 1, "sanity");
2016   int offset   = align_to_ref_p.offset_in_bytes() / elt_size;
2017   Node *offsn  = _igvn.intcon(offset);
2018 
2019   Node *e = offsn;
2020   if (align_to_ref_p.invar() != NULL) {
2021     // incorporate any extra invariant piece producing (offset +/- invar) >>> log2(elt)
2022     Node* log2_elt = _igvn.intcon(exact_log2(elt_size));
2023     Node* aref     = new (_phase->C) URShiftINode(align_to_ref_p.invar(), log2_elt);
2024     _igvn.register_new_node_with_optimizer(aref);
2025     _phase->set_ctrl(aref, pre_ctrl);
2026     if (align_to_ref_p.negate_invar()) {
2027       e = new (_phase->C) SubINode(e, aref);
2028     } else {
2029       e = new (_phase->C) AddINode(e, aref);
2030     }
2031     _igvn.register_new_node_with_optimizer(e);
2032     _phase->set_ctrl(e, pre_ctrl);
2033   }
2034   if (vw > ObjectAlignmentInBytes) {
2035     // incorporate base e +/- base && Mask >>> log2(elt)
2036     Node* xbase = new(_phase->C) CastP2XNode(NULL, align_to_ref_p.base());
2037     _igvn.register_new_node_with_optimizer(xbase);
2038 #ifdef _LP64
2039     xbase  = new (_phase->C) ConvL2INode(xbase);
2040     _igvn.register_new_node_with_optimizer(xbase);
2041 #endif
2042     Node* mask = _igvn.intcon(vw-1);
2043     Node* masked_xbase  = new (_phase->C) AndINode(xbase, mask);
2044     _igvn.register_new_node_with_optimizer(masked_xbase);
2045     Node* log2_elt = _igvn.intcon(exact_log2(elt_size));
2046     Node* bref     = new (_phase->C) URShiftINode(masked_xbase, log2_elt);
2047     _igvn.register_new_node_with_optimizer(bref);
2048     _phase->set_ctrl(bref, pre_ctrl);
2049     e = new (_phase->C) AddINode(e, bref);
2050     _igvn.register_new_node_with_optimizer(e);
2051     _phase->set_ctrl(e, pre_ctrl);
2052   }
2053 
2054   // compute e +/- lim0
2055   if (scale < 0) {
2056     e = new (_phase->C) SubINode(e, lim0);
2057   } else {
2058     e = new (_phase->C) AddINode(e, lim0);
2059   }
2060   _igvn.register_new_node_with_optimizer(e);
2061   _phase->set_ctrl(e, pre_ctrl);
2062 
2063   if (stride * scale > 0) {
2064     // compute V - (e +/- lim0)
2065     Node* va  = _igvn.intcon(v_align);
2066     e = new (_phase->C) SubINode(va, e);
2067     _igvn.register_new_node_with_optimizer(e);
2068     _phase->set_ctrl(e, pre_ctrl);
2069   }
2070   // compute N = (exp) % V
2071   Node* va_msk = _igvn.intcon(v_align - 1);
2072   Node* N = new (_phase->C) AndINode(e, va_msk);
2073   _igvn.register_new_node_with_optimizer(N);
2074   _phase->set_ctrl(N, pre_ctrl);
2075 
2076   //   substitute back into (1), so that new limit
2077   //     lim = lim0 + N
2078   Node* lim;
2079   if (stride < 0) {
2080     lim = new (_phase->C) SubINode(lim0, N);
2081   } else {
2082     lim = new (_phase->C) AddINode(lim0, N);
2083   }
2084   _igvn.register_new_node_with_optimizer(lim);
2085   _phase->set_ctrl(lim, pre_ctrl);
2086   Node* constrained =
2087     (stride > 0) ? (Node*) new (_phase->C) MinINode(lim, orig_limit)
2088                  : (Node*) new (_phase->C) MaxINode(lim, orig_limit);
2089   _igvn.register_new_node_with_optimizer(constrained);
2090   _phase->set_ctrl(constrained, pre_ctrl);
2091   _igvn.hash_delete(pre_opaq);
2092   pre_opaq->set_req(1, constrained);
2093 }
2094 
2095 //----------------------------get_pre_loop_end---------------------------
2096 // Find pre loop end from main loop.  Returns null if none.
2097 CountedLoopEndNode* SuperWord::get_pre_loop_end(CountedLoopNode *cl) {
2098   Node *ctrl = cl->in(LoopNode::EntryControl);
2099   if (!ctrl->is_IfTrue() && !ctrl->is_IfFalse()) return NULL;
2100   Node *iffm = ctrl->in(0);
2101   if (!iffm->is_If()) return NULL;
2102   Node *p_f = iffm->in(0);
2103   if (!p_f->is_IfFalse()) return NULL;
2104   if (!p_f->in(0)->is_CountedLoopEnd()) return NULL;
2105   CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd();
2106   if (!pre_end->loopnode()->is_pre_loop()) return NULL;
2107   return pre_end;
2108 }
2109 
2110 
2111 //------------------------------init---------------------------
2112 void SuperWord::init() {
2113   _dg.init();
2114   _packset.clear();
2115   _disjoint_ptrs.clear();
2116   _block.clear();
2117   _data_entry.clear();
2118   _mem_slice_head.clear();
2119   _mem_slice_tail.clear();
2120   _node_info.clear();
2121   _align_to_ref = NULL;
2122   _lpt = NULL;
2123   _lp = NULL;
2124   _bb = NULL;
2125   _iv = NULL;
2126 }
2127 
2128 //------------------------------print_packset---------------------------
2129 void SuperWord::print_packset() {
2130 #ifndef PRODUCT
2131   tty->print_cr("packset");
2132   for (int i = 0; i < _packset.length(); i++) {
2133     tty->print_cr("Pack: %d", i);
2134     Node_List* p = _packset.at(i);
2135     print_pack(p);
2136   }
2137 #endif
2138 }
2139 
2140 //------------------------------print_pack---------------------------
2141 void SuperWord::print_pack(Node_List* p) {
2142   for (uint i = 0; i < p->size(); i++) {
2143     print_stmt(p->at(i));
2144   }
2145 }
2146 
2147 //------------------------------print_bb---------------------------
2148 void SuperWord::print_bb() {
2149 #ifndef PRODUCT
2150   tty->print_cr("\nBlock");
2151   for (int i = 0; i < _block.length(); i++) {
2152     Node* n = _block.at(i);
2153     tty->print("%d ", i);
2154     if (n) {
2155       n->dump();
2156     }
2157   }
2158 #endif
2159 }
2160 
2161 //------------------------------print_stmt---------------------------
2162 void SuperWord::print_stmt(Node* s) {
2163 #ifndef PRODUCT
2164   tty->print(" align: %d \t", alignment(s));
2165   s->dump();
2166 #endif
2167 }
2168 
2169 //------------------------------blank---------------------------
2170 char* SuperWord::blank(uint depth) {
2171   static char blanks[101];
2172   assert(depth < 101, "too deep");
2173   for (uint i = 0; i < depth; i++) blanks[i] = ' ';
2174   blanks[depth] = '\0';
2175   return blanks;
2176 }
2177 
2178 
2179 //==============================SWPointer===========================
2180 
2181 //----------------------------SWPointer------------------------
2182 SWPointer::SWPointer(MemNode* mem, SuperWord* slp) :
2183   _mem(mem), _slp(slp),  _base(NULL),  _adr(NULL),
2184   _scale(0), _offset(0), _invar(NULL), _negate_invar(false) {
2185 
2186   Node* adr = mem->in(MemNode::Address);
2187   if (!adr->is_AddP()) {
2188     assert(!valid(), "too complex");
2189     return;
2190   }
2191   // Match AddP(base, AddP(ptr, k*iv [+ invariant]), constant)
2192   Node* base = adr->in(AddPNode::Base);
2193   //unsafe reference could not be aligned appropriately without runtime checking
2194   if (base == NULL || base->bottom_type() == Type::TOP) {
2195     assert(!valid(), "unsafe access");
2196     return;
2197   }
2198   for (int i = 0; i < 3; i++) {
2199     if (!scaled_iv_plus_offset(adr->in(AddPNode::Offset))) {
2200       assert(!valid(), "too complex");
2201       return;
2202     }
2203     adr = adr->in(AddPNode::Address);
2204     if (base == adr || !adr->is_AddP()) {
2205       break; // stop looking at addp's
2206     }
2207   }
2208   _base = base;
2209   _adr  = adr;
2210   assert(valid(), "Usable");
2211 }
2212 
2213 // Following is used to create a temporary object during
2214 // the pattern match of an address expression.
2215 SWPointer::SWPointer(SWPointer* p) :
2216   _mem(p->_mem), _slp(p->_slp),  _base(NULL),  _adr(NULL),
2217   _scale(0), _offset(0), _invar(NULL), _negate_invar(false) {}
2218 
2219 //------------------------scaled_iv_plus_offset--------------------
2220 // Match: k*iv + offset
2221 // where: k is a constant that maybe zero, and
2222 //        offset is (k2 [+/- invariant]) where k2 maybe zero and invariant is optional
2223 bool SWPointer::scaled_iv_plus_offset(Node* n) {
2224   if (scaled_iv(n)) {
2225     return true;
2226   }
2227   if (offset_plus_k(n)) {
2228     return true;
2229   }
2230   int opc = n->Opcode();
2231   if (opc == Op_AddI) {
2232     if (scaled_iv(n->in(1)) && offset_plus_k(n->in(2))) {
2233       return true;
2234     }
2235     if (scaled_iv(n->in(2)) && offset_plus_k(n->in(1))) {
2236       return true;
2237     }
2238   } else if (opc == Op_SubI) {
2239     if (scaled_iv(n->in(1)) && offset_plus_k(n->in(2), true)) {
2240       return true;
2241     }
2242     if (scaled_iv(n->in(2)) && offset_plus_k(n->in(1))) {
2243       _scale *= -1;
2244       return true;
2245     }
2246   }
2247   return false;
2248 }
2249 
2250 //----------------------------scaled_iv------------------------
2251 // Match: k*iv where k is a constant that's not zero
2252 bool SWPointer::scaled_iv(Node* n) {
2253   if (_scale != 0) {
2254     return false;  // already found a scale
2255   }
2256   if (n == iv()) {
2257     _scale = 1;
2258     return true;
2259   }
2260   int opc = n->Opcode();
2261   if (opc == Op_MulI) {
2262     if (n->in(1) == iv() && n->in(2)->is_Con()) {
2263       _scale = n->in(2)->get_int();
2264       return true;
2265     } else if (n->in(2) == iv() && n->in(1)->is_Con()) {
2266       _scale = n->in(1)->get_int();
2267       return true;
2268     }
2269   } else if (opc == Op_LShiftI) {
2270     if (n->in(1) == iv() && n->in(2)->is_Con()) {
2271       _scale = 1 << n->in(2)->get_int();
2272       return true;
2273     }
2274   } else if (opc == Op_ConvI2L) {
2275     if (scaled_iv_plus_offset(n->in(1))) {
2276       return true;
2277     }
2278   } else if (opc == Op_LShiftL) {
2279     if (!has_iv() && _invar == NULL) {
2280       // Need to preserve the current _offset value, so
2281       // create a temporary object for this expression subtree.
2282       // Hacky, so should re-engineer the address pattern match.
2283       SWPointer tmp(this);
2284       if (tmp.scaled_iv_plus_offset(n->in(1))) {
2285         if (tmp._invar == NULL) {
2286           int mult = 1 << n->in(2)->get_int();
2287           _scale   = tmp._scale  * mult;
2288           _offset += tmp._offset * mult;
2289           return true;
2290         }
2291       }
2292     }
2293   }
2294   return false;
2295 }
2296 
2297 //----------------------------offset_plus_k------------------------
2298 // Match: offset is (k [+/- invariant])
2299 // where k maybe zero and invariant is optional, but not both.
2300 bool SWPointer::offset_plus_k(Node* n, bool negate) {
2301   int opc = n->Opcode();
2302   if (opc == Op_ConI) {
2303     _offset += negate ? -(n->get_int()) : n->get_int();
2304     return true;
2305   } else if (opc == Op_ConL) {
2306     // Okay if value fits into an int
2307     const TypeLong* t = n->find_long_type();
2308     if (t->higher_equal(TypeLong::INT)) {
2309       jlong loff = n->get_long();
2310       jint  off  = (jint)loff;
2311       _offset += negate ? -off : loff;
2312       return true;
2313     }
2314     return false;
2315   }
2316   if (_invar != NULL) return false; // already have an invariant
2317   if (opc == Op_AddI) {
2318     if (n->in(2)->is_Con() && invariant(n->in(1))) {
2319       _negate_invar = negate;
2320       _invar = n->in(1);
2321       _offset += negate ? -(n->in(2)->get_int()) : n->in(2)->get_int();
2322       return true;
2323     } else if (n->in(1)->is_Con() && invariant(n->in(2))) {
2324       _offset += negate ? -(n->in(1)->get_int()) : n->in(1)->get_int();
2325       _negate_invar = negate;
2326       _invar = n->in(2);
2327       return true;
2328     }
2329   }
2330   if (opc == Op_SubI) {
2331     if (n->in(2)->is_Con() && invariant(n->in(1))) {
2332       _negate_invar = negate;
2333       _invar = n->in(1);
2334       _offset += !negate ? -(n->in(2)->get_int()) : n->in(2)->get_int();
2335       return true;
2336     } else if (n->in(1)->is_Con() && invariant(n->in(2))) {
2337       _offset += negate ? -(n->in(1)->get_int()) : n->in(1)->get_int();
2338       _negate_invar = !negate;
2339       _invar = n->in(2);
2340       return true;
2341     }
2342   }
2343   if (invariant(n)) {
2344     _negate_invar = negate;
2345     _invar = n;
2346     return true;
2347   }
2348   return false;
2349 }
2350 
2351 //----------------------------print------------------------
2352 void SWPointer::print() {
2353 #ifndef PRODUCT
2354   tty->print("base: %d  adr: %d  scale: %d  offset: %d  invar: %c%d\n",
2355              _base != NULL ? _base->_idx : 0,
2356              _adr  != NULL ? _adr->_idx  : 0,
2357              _scale, _offset,
2358              _negate_invar?'-':'+',
2359              _invar != NULL ? _invar->_idx : 0);
2360 #endif
2361 }
2362 
2363 // ========================= OrderedPair =====================
2364 
2365 const OrderedPair OrderedPair::initial;
2366 
2367 // ========================= SWNodeInfo =====================
2368 
2369 const SWNodeInfo SWNodeInfo::initial;
2370 
2371 
2372 // ============================ DepGraph ===========================
2373 
2374 //------------------------------make_node---------------------------
2375 // Make a new dependence graph node for an ideal node.
2376 DepMem* DepGraph::make_node(Node* node) {
2377   DepMem* m = new (_arena) DepMem(node);
2378   if (node != NULL) {
2379     assert(_map.at_grow(node->_idx) == NULL, "one init only");
2380     _map.at_put_grow(node->_idx, m);
2381   }
2382   return m;
2383 }
2384 
2385 //------------------------------make_edge---------------------------
2386 // Make a new dependence graph edge from dpred -> dsucc
2387 DepEdge* DepGraph::make_edge(DepMem* dpred, DepMem* dsucc) {
2388   DepEdge* e = new (_arena) DepEdge(dpred, dsucc, dsucc->in_head(), dpred->out_head());
2389   dpred->set_out_head(e);
2390   dsucc->set_in_head(e);
2391   return e;
2392 }
2393 
2394 // ========================== DepMem ========================
2395 
2396 //------------------------------in_cnt---------------------------
2397 int DepMem::in_cnt() {
2398   int ct = 0;
2399   for (DepEdge* e = _in_head; e != NULL; e = e->next_in()) ct++;
2400   return ct;
2401 }
2402 
2403 //------------------------------out_cnt---------------------------
2404 int DepMem::out_cnt() {
2405   int ct = 0;
2406   for (DepEdge* e = _out_head; e != NULL; e = e->next_out()) ct++;
2407   return ct;
2408 }
2409 
2410 //------------------------------print-----------------------------
2411 void DepMem::print() {
2412 #ifndef PRODUCT
2413   tty->print("  DepNode %d (", _node->_idx);
2414   for (DepEdge* p = _in_head; p != NULL; p = p->next_in()) {
2415     Node* pred = p->pred()->node();
2416     tty->print(" %d", pred != NULL ? pred->_idx : 0);
2417   }
2418   tty->print(") [");
2419   for (DepEdge* s = _out_head; s != NULL; s = s->next_out()) {
2420     Node* succ = s->succ()->node();
2421     tty->print(" %d", succ != NULL ? succ->_idx : 0);
2422   }
2423   tty->print_cr(" ]");
2424 #endif
2425 }
2426 
2427 // =========================== DepEdge =========================
2428 
2429 //------------------------------DepPreds---------------------------
2430 void DepEdge::print() {
2431 #ifndef PRODUCT
2432   tty->print_cr("DepEdge: %d [ %d ]", _pred->node()->_idx, _succ->node()->_idx);
2433 #endif
2434 }
2435 
2436 // =========================== DepPreds =========================
2437 // Iterator over predecessor edges in the dependence graph.
2438 
2439 //------------------------------DepPreds---------------------------
2440 DepPreds::DepPreds(Node* n, DepGraph& dg) {
2441   _n = n;
2442   _done = false;
2443   if (_n->is_Store() || _n->is_Load()) {
2444     _next_idx = MemNode::Address;
2445     _end_idx  = n->req();
2446     _dep_next = dg.dep(_n)->in_head();
2447   } else if (_n->is_Mem()) {
2448     _next_idx = 0;
2449     _end_idx  = 0;
2450     _dep_next = dg.dep(_n)->in_head();
2451   } else {
2452     _next_idx = 1;
2453     _end_idx  = _n->req();
2454     _dep_next = NULL;
2455   }
2456   next();
2457 }
2458 
2459 //------------------------------next---------------------------
2460 void DepPreds::next() {
2461   if (_dep_next != NULL) {
2462     _current  = _dep_next->pred()->node();
2463     _dep_next = _dep_next->next_in();
2464   } else if (_next_idx < _end_idx) {
2465     _current  = _n->in(_next_idx++);
2466   } else {
2467     _done = true;
2468   }
2469 }
2470 
2471 // =========================== DepSuccs =========================
2472 // Iterator over successor edges in the dependence graph.
2473 
2474 //------------------------------DepSuccs---------------------------
2475 DepSuccs::DepSuccs(Node* n, DepGraph& dg) {
2476   _n = n;
2477   _done = false;
2478   if (_n->is_Load()) {
2479     _next_idx = 0;
2480     _end_idx  = _n->outcnt();
2481     _dep_next = dg.dep(_n)->out_head();
2482   } else if (_n->is_Mem() || _n->is_Phi() && _n->bottom_type() == Type::MEMORY) {
2483     _next_idx = 0;
2484     _end_idx  = 0;
2485     _dep_next = dg.dep(_n)->out_head();
2486   } else {
2487     _next_idx = 0;
2488     _end_idx  = _n->outcnt();
2489     _dep_next = NULL;
2490   }
2491   next();
2492 }
2493 
2494 //-------------------------------next---------------------------
2495 void DepSuccs::next() {
2496   if (_dep_next != NULL) {
2497     _current  = _dep_next->succ()->node();
2498     _dep_next = _dep_next->next_out();
2499   } else if (_next_idx < _end_idx) {
2500     _current  = _n->raw_out(_next_idx++);
2501   } else {
2502     _done = true;
2503   }
2504 }