jdk8-mips64-public/hotspot: src/share/vm/opto/superword.cpp@eb7ce841ccec (annotated)

src/share/vm/opto/superword.cpp@eb7ce841ccec (annotated)

src/share/vm/opto/superword.cpp

Sat, 24 Oct 2020 16:43:47 +0800

author: aoqi
date: Sat, 24 Oct 2020 16:43:47 +0800
changeset 10015: eb7ce841ccec
parent 9806: 758c07667682
parent 9977: e649f2136368
permissions: -rw-r--r--

Merge

 /*
  * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 #include "precompiled.hpp"
 #include "compiler/compileLog.hpp"
 #include "libadt/vectset.hpp"
 #include "memory/allocation.inline.hpp"
 #include "opto/addnode.hpp"
 #include "opto/callnode.hpp"
 #include "opto/divnode.hpp"
 #include "opto/matcher.hpp"
 #include "opto/memnode.hpp"
 #include "opto/mulnode.hpp"
 #include "opto/opcodes.hpp"
 #include "opto/superword.hpp"
 #include "opto/vectornode.hpp"
 //
 //                  S U P E R W O R D   T R A N S F O R M
 //=============================================================================
 //------------------------------SuperWord---------------------------
 SuperWord::SuperWord(PhaseIdealLoop* phase) :
   _phase(phase),
   _igvn(phase->_igvn),
   _arena(phase->C->comp_arena()),
   _packset(arena(), 8,  0, NULL),         // packs for the current block
   _bb_idx(arena(), (int)(1.10 * phase->C->unique()), 0, 0), // node idx to index in bb
   _block(arena(), 8,  0, NULL),           // nodes in current block
   _data_entry(arena(), 8,  0, NULL),      // nodes with all inputs from outside
   _mem_slice_head(arena(), 8,  0, NULL),  // memory slice heads
   _mem_slice_tail(arena(), 8,  0, NULL),  // memory slice tails
   _node_info(arena(), 8,  0, SWNodeInfo::initial), // info needed per node
   _align_to_ref(NULL),                    // memory reference to align vectors to
   _disjoint_ptrs(arena(), 8,  0, OrderedPair::initial), // runtime disambiguated pointer pairs
   _dg(_arena),                            // dependence graph
   _visited(arena()),                      // visited node set
   _post_visited(arena()),                 // post visited node set
   _n_idx_list(arena(), 8),                // scratch list of (node,index) pairs
   _stk(arena(), 8, 0, NULL),              // scratch stack of nodes
   _nlist(arena(), 8, 0, NULL),            // scratch list of nodes
   _lpt(NULL),                             // loop tree node
   _lp(NULL),                              // LoopNode
   _bb(NULL),                              // basic block
   _iv(NULL)                               // induction var
 {}
 //------------------------------transform_loop---------------------------
 void SuperWord::transform_loop(IdealLoopTree* lpt) {
   assert(UseSuperWord, "should be");
   // Do vectors exist on this architecture?
   if (Matcher::vector_width_in_bytes(T_BYTE) < 2) return;
   assert(lpt->_head->is_CountedLoop(), "must be");
   CountedLoopNode *cl = lpt->_head->as_CountedLoop();
   if (!cl->is_valid_counted_loop()) return; // skip malformed counted loop
   if (!cl->is_main_loop() ) return; // skip normal, pre, and post loops
   // Check for no control flow in body (other than exit)
   Node *cl_exit = cl->loopexit();
   if (cl_exit->in(0) != lpt->_head) return;
   // Make sure the are no extra control users of the loop backedge
   if (cl->back_control()->outcnt() != 1) {
     return;
   }
   // Check for pre-loop ending with CountedLoopEnd(Bool(Cmp(x,Opaque1(limit))))
   CountedLoopEndNode* pre_end = get_pre_loop_end(cl);
   if (pre_end == NULL) return;
   Node *pre_opaq1 = pre_end->limit();
   if (pre_opaq1->Opcode() != Op_Opaque1) return;
   init(); // initialize data structures
   set_lpt(lpt);
   set_lp(cl);
   // For now, define one block which is the entire loop body
   set_bb(cl);
   assert(_packset.length() == 0, "packset must be empty");
   SLP_extract();
 }
 //------------------------------SLP_extract---------------------------
 // Extract the superword level parallelism
 //
 // 1) A reverse post-order of nodes in the block is constructed.  By scanning
 //    this list from first to last, all definitions are visited before their uses.
 //
 // 2) A point-to-point dependence graph is constructed between memory references.
 //    This simplies the upcoming "independence" checker.
 //
 // 3) The maximum depth in the node graph from the beginning of the block
 //    to each node is computed.  This is used to prune the graph search
 //    in the independence checker.
 //
 // 4) For integer types, the necessary bit width is propagated backwards
 //    from stores to allow packed operations on byte, char, and short
 //    integers.  This reverses the promotion to type "int" that javac
 //    did for operations like: char c1,c2,c3;  c1 = c2 + c3.
 //
 // 5) One of the memory references is picked to be an aligned vector reference.
 //    The pre-loop trip count is adjusted to align this reference in the
 //    unrolled body.
 //
 // 6) The initial set of pack pairs is seeded with memory references.
 //
 // 7) The set of pack pairs is extended by following use->def and def->use links.
 //
 // 8) The pairs are combined into vector sized packs.
 //
 // 9) Reorder the memory slices to co-locate members of the memory packs.
 //
 // 10) Generate ideal vector nodes for the final set of packs and where necessary,
 //    inserting scalar promotion, vector creation from multiple scalars, and
 //    extraction of scalar values from vectors.
 //
 void SuperWord::SLP_extract() {
   // Ready the block
   if (!construct_bb())
     return; // Exit if no interesting nodes or complex graph.
   dependence_graph();
   compute_max_depth();
   compute_vector_element_type();
   // Attempt vectorization
   find_adjacent_refs();
   extend_packlist();
   combine_packs();
   construct_my_pack_map();
   filter_packs();
   schedule();
   output();
 }
 //------------------------------find_adjacent_refs---------------------------
 // Find the adjacent memory references and create pack pairs for them.
 // This is the initial set of packs that will then be extended by
 // following use->def and def->use links.  The align positions are
 // assigned relative to the reference "align_to_ref"
 void SuperWord::find_adjacent_refs() {
   // Get list of memory operations
   Node_List memops;
   for (int i = 0; i < _block.length(); i++) {
     Node* n = _block.at(i);
     if (n->is_Mem() && !n->is_LoadStore() && in_bb(n) &&
         is_java_primitive(n->as_Mem()->memory_type())) {
       int align = memory_alignment(n->as_Mem(), 0);
       if (align != bottom_align) {
         memops.push(n);
       }
     }
   }
   Node_List align_to_refs;
   int best_iv_adjustment = 0;
   MemNode* best_align_to_mem_ref = NULL;
   while (memops.size() != 0) {
     // Find a memory reference to align to.
     MemNode* mem_ref = find_align_to_ref(memops);
     if (mem_ref == NULL) break;
     align_to_refs.push(mem_ref);
     int iv_adjustment = get_iv_adjustment(mem_ref);
     if (best_align_to_mem_ref == NULL) {
       // Set memory reference which is the best from all memory operations
       // to be used for alignment. The pre-loop trip count is modified to align
       // this reference to a vector-aligned address.
       best_align_to_mem_ref = mem_ref;
       best_iv_adjustment = iv_adjustment;
     }
     SWPointer align_to_ref_p(mem_ref, this);
     // Set alignment relative to "align_to_ref" for all related memory operations.
     for (int i = memops.size() - 1; i >= 0; i--) {
       MemNode* s = memops.at(i)->as_Mem();
       if (isomorphic(s, mem_ref)) {
         SWPointer p2(s, this);
         if (p2.comparable(align_to_ref_p)) {
           int align = memory_alignment(s, iv_adjustment);
           set_alignment(s, align);
         }
       }
     }
     // Create initial pack pairs of memory operations for which
     // alignment is set and vectors will be aligned.
     bool create_pack = true;
     if (memory_alignment(mem_ref, best_iv_adjustment) == 0) {
       if (!Matcher::misaligned_vectors_ok()) {
         int vw = vector_width(mem_ref);
         int vw_best = vector_width(best_align_to_mem_ref);
         if (vw > vw_best) {
           // Do not vectorize a memory access with more elements per vector
           // if unaligned memory access is not allowed because number of
           // iterations in pre-loop will be not enough to align it.
           create_pack = false;
         } else {
           SWPointer p2(best_align_to_mem_ref, this);
           if (align_to_ref_p.invar() != p2.invar()) {
             // Do not vectorize memory accesses with different invariants
             // if unaligned memory accesses are not allowed.
             create_pack = false;
           }
         }
       }
     } else {
       if (same_velt_type(mem_ref, best_align_to_mem_ref)) {
         // Can't allow vectorization of unaligned memory accesses with the
         // same type since it could be overlapped accesses to the same array.
         create_pack = false;
       } else {
         // Allow independent (different type) unaligned memory operations
         // if HW supports them.
         if (!Matcher::misaligned_vectors_ok()) {
           create_pack = false;
         } else {
           // Check if packs of the same memory type but
           // with a different alignment were created before.
           for (uint i = 0; i < align_to_refs.size(); i++) {
             MemNode* mr = align_to_refs.at(i)->as_Mem();
             if (same_velt_type(mr, mem_ref) &&
                 memory_alignment(mr, iv_adjustment) != 0)
               create_pack = false;
           }
         }
       }
     }
     if (create_pack) {
       for (uint i = 0; i < memops.size(); i++) {
         Node* s1 = memops.at(i);
         int align = alignment(s1);
         if (align == top_align) continue;
         for (uint j = 0; j < memops.size(); j++) {
           Node* s2 = memops.at(j);
           if (alignment(s2) == top_align) continue;
           if (s1 != s2 && are_adjacent_refs(s1, s2)) {
             if (stmts_can_pack(s1, s2, align)) {
               Node_List* pair = new Node_List();
               pair->push(s1);
               pair->push(s2);
               _packset.append(pair);
             }
           }
         }
       }
     } else { // Don't create unaligned pack
       // First, remove remaining memory ops of the same type from the list.
       for (int i = memops.size() - 1; i >= 0; i--) {
         MemNode* s = memops.at(i)->as_Mem();
         if (same_velt_type(s, mem_ref)) {
           memops.remove(i);
         }
       }
       // Second, remove already constructed packs of the same type.
       for (int i = _packset.length() - 1; i >= 0; i--) {
         Node_List* p = _packset.at(i);
         MemNode* s = p->at(0)->as_Mem();
         if (same_velt_type(s, mem_ref)) {
           remove_pack_at(i);
         }
       }
       // If needed find the best memory reference for loop alignment again.
       if (same_velt_type(mem_ref, best_align_to_mem_ref)) {
         // Put memory ops from remaining packs back on memops list for
         // the best alignment search.
         uint orig_msize = memops.size();
         for (int i = 0; i < _packset.length(); i++) {
           Node_List* p = _packset.at(i);
           MemNode* s = p->at(0)->as_Mem();
           assert(!same_velt_type(s, mem_ref), "sanity");
           memops.push(s);
         }
         MemNode* best_align_to_mem_ref = find_align_to_ref(memops);
         if (best_align_to_mem_ref == NULL) break;
         best_iv_adjustment = get_iv_adjustment(best_align_to_mem_ref);
         // Restore list.
         while (memops.size() > orig_msize)
           (void)memops.pop();
       }
     } // unaligned memory accesses
     // Remove used mem nodes.
     for (int i = memops.size() - 1; i >= 0; i--) {
       MemNode* m = memops.at(i)->as_Mem();
       if (alignment(m) != top_align) {
         memops.remove(i);
       }
     }
   } // while (memops.size() != 0
   set_align_to_ref(best_align_to_mem_ref);
 #ifndef PRODUCT
   if (TraceSuperWord) {
     tty->print_cr("\nAfter find_adjacent_refs");
     print_packset();
   }
 #endif
 }
 //------------------------------find_align_to_ref---------------------------
 // Find a memory reference to align the loop induction variable to.
 // Looks first at stores then at loads, looking for a memory reference
 // with the largest number of references similar to it.
 MemNode* SuperWord::find_align_to_ref(Node_List &memops) {
   GrowableArray<int> cmp_ct(arena(), memops.size(), memops.size(), 0);
   // Count number of comparable memory ops
   for (uint i = 0; i < memops.size(); i++) {
     MemNode* s1 = memops.at(i)->as_Mem();
     SWPointer p1(s1, this);
     // Discard if pre loop can't align this reference
     if (!ref_is_alignable(p1)) {
       *cmp_ct.adr_at(i) = 0;
       continue;
     }
     for (uint j = i+1; j < memops.size(); j++) {
       MemNode* s2 = memops.at(j)->as_Mem();
       if (isomorphic(s1, s2)) {
         SWPointer p2(s2, this);
         if (p1.comparable(p2)) {
           (*cmp_ct.adr_at(i))++;
           (*cmp_ct.adr_at(j))++;
         }
       }
     }
   }
   // Find Store (or Load) with the greatest number of "comparable" references,
   // biggest vector size, smallest data size and smallest iv offset.
   int max_ct        = 0;
   int max_vw        = 0;
   int max_idx       = -1;
   int min_size      = max_jint;
   int min_iv_offset = max_jint;
   for (uint j = 0; j < memops.size(); j++) {
     MemNode* s = memops.at(j)->as_Mem();
     if (s->is_Store()) {
       int vw = vector_width_in_bytes(s);
       assert(vw > 1, "sanity");
       SWPointer p(s, this);
       if (cmp_ct.at(j) >  max_ct ||
           cmp_ct.at(j) == max_ct &&
             (vw >  max_vw ||
              vw == max_vw &&
               (data_size(s) <  min_size ||
                data_size(s) == min_size &&
                  (p.offset_in_bytes() < min_iv_offset)))) {
         max_ct = cmp_ct.at(j);
         max_vw = vw;
         max_idx = j;
         min_size = data_size(s);
         min_iv_offset = p.offset_in_bytes();
       }
     }
   }
   // If no stores, look at loads
   if (max_ct == 0) {
     for (uint j = 0; j < memops.size(); j++) {
       MemNode* s = memops.at(j)->as_Mem();
       if (s->is_Load()) {
         int vw = vector_width_in_bytes(s);
         assert(vw > 1, "sanity");
         SWPointer p(s, this);
         if (cmp_ct.at(j) >  max_ct ||
             cmp_ct.at(j) == max_ct &&
               (vw >  max_vw ||
                vw == max_vw &&
                 (data_size(s) <  min_size ||
                  data_size(s) == min_size &&
                    (p.offset_in_bytes() < min_iv_offset)))) {
           max_ct = cmp_ct.at(j);
           max_vw = vw;
           max_idx = j;
           min_size = data_size(s);
           min_iv_offset = p.offset_in_bytes();
         }
       }
     }
   }
 #ifdef ASSERT
   if (TraceSuperWord && Verbose) {
     tty->print_cr("\nVector memops after find_align_to_refs");
     for (uint i = 0; i < memops.size(); i++) {
       MemNode* s = memops.at(i)->as_Mem();
       s->dump();
     }
   }
 #endif
   if (max_ct > 0) {
 #ifdef ASSERT
     if (TraceSuperWord) {
       tty->print("\nVector align to node: ");
       memops.at(max_idx)->as_Mem()->dump();
     }
 #endif
     return memops.at(max_idx)->as_Mem();
   }
   return NULL;
 }
 //------------------------------ref_is_alignable---------------------------
 // Can the preloop align the reference to position zero in the vector?
 bool SuperWord::ref_is_alignable(SWPointer& p) {
   if (!p.has_iv()) {
     return true;   // no induction variable
   }
   CountedLoopEndNode* pre_end = get_pre_loop_end(lp()->as_CountedLoop());
   assert(pre_end != NULL, "we must have a correct pre-loop");
   assert(pre_end->stride_is_con(), "pre loop stride is constant");
   int preloop_stride = pre_end->stride_con();
   int span = preloop_stride * p.scale_in_bytes();
   int mem_size = p.memory_size();
   int offset   = p.offset_in_bytes();
   // Stride one accesses are alignable if offset is aligned to memory operation size.
   // Offset can be unaligned when UseUnalignedAccesses is used.
   if (ABS(span) == mem_size && (ABS(offset) % mem_size) == 0) {
     return true;
   }
   // If the initial offset from start of the object is computable,
   // check if the pre-loop can align the final offset accordingly.
   //
   // In other words: Can we find an i such that the offset
   // after i pre-loop iterations is aligned to vw?
   //   (init_offset + pre_loop) % vw == 0              (1)
   // where
   //   pre_loop = i * span
   // is the number of bytes added to the offset by i pre-loop iterations.
   //
   // For this to hold we need pre_loop to increase init_offset by
   //   pre_loop = vw - (init_offset % vw)
   //
   // This is only possible if pre_loop is divisible by span because each
   // pre-loop iteration increases the initial offset by 'span' bytes:
   //   (vw - (init_offset % vw)) % span == 0
   //
   int vw = vector_width_in_bytes(p.mem());
   assert(vw > 1, "sanity");
   Node* init_nd = pre_end->init_trip();
   if (init_nd->is_Con() && p.invar() == NULL) {
     int init = init_nd->bottom_type()->is_int()->get_con();
     int init_offset = init * p.scale_in_bytes() + offset;
     if (init_offset < 0) { // negative offset from object start?
       return false;        // may happen in dead loop
     }
     if (vw % span == 0) {
       // If vm is a multiple of span, we use formula (1).
       if (span > 0) {
         return (vw - (init_offset % vw)) % span == 0;
       } else {
         assert(span < 0, "nonzero stride * scale");
         return (init_offset % vw) % -span == 0;
       }
     } else if (span % vw == 0) {
       // If span is a multiple of vw, we can simplify formula (1) to:
       //   (init_offset + i * span) % vw == 0
       //     =>
       //   (init_offset % vw) + ((i * span) % vw) == 0
       //     =>
       //   init_offset % vw == 0
       //
       // Because we add a multiple of vw to the initial offset, the final
       // offset is a multiple of vw if and only if init_offset is a multiple.
       //
       return (init_offset % vw) == 0;
     }
   }
   return false;
 }
 //---------------------------get_iv_adjustment---------------------------
 // Calculate loop's iv adjustment for this memory ops.
 int SuperWord::get_iv_adjustment(MemNode* mem_ref) {
   SWPointer align_to_ref_p(mem_ref, this);
   int offset = align_to_ref_p.offset_in_bytes();
   int scale  = align_to_ref_p.scale_in_bytes();
   int elt_size = align_to_ref_p.memory_size();
   int vw       = vector_width_in_bytes(mem_ref);
   assert(vw > 1, "sanity");
   int iv_adjustment;
   if (scale != 0) {
     int stride_sign = (scale * iv_stride()) > 0 ? 1 : -1;
     // At least one iteration is executed in pre-loop by default. As result
     // several iterations are needed to align memory operations in main-loop even
     // if offset is 0.
     int iv_adjustment_in_bytes = (stride_sign * vw - (offset % vw));
     assert(((ABS(iv_adjustment_in_bytes) % elt_size) == 0),
            err_msg_res("(%d) should be divisible by (%d)", iv_adjustment_in_bytes, elt_size));
     iv_adjustment = iv_adjustment_in_bytes/elt_size;
   } else {
     // This memory op is not dependent on iv (scale == 0)
     iv_adjustment = 0;
   }
 #ifndef PRODUCT
   if (TraceSuperWord)
     tty->print_cr("\noffset = %d iv_adjust = %d elt_size = %d scale = %d iv_stride = %d vect_size %d",
                   offset, iv_adjustment, elt_size, scale, iv_stride(), vw);
 #endif
   return iv_adjustment;
 }
 //---------------------------dependence_graph---------------------------
 // Construct dependency graph.
 // Add dependence edges to load/store nodes for memory dependence
 //    A.out()->DependNode.in(1) and DependNode.out()->B.prec(x)
 void SuperWord::dependence_graph() {
   // First, assign a dependence node to each memory node
   for (int i = 0; i < _block.length(); i++ ) {
     Node *n = _block.at(i);
     if (n->is_Mem() || n->is_Phi() && n->bottom_type() == Type::MEMORY) {
       _dg.make_node(n);
     }
   }
   // For each memory slice, create the dependences
   for (int i = 0; i < _mem_slice_head.length(); i++) {
     Node* n      = _mem_slice_head.at(i);
     Node* n_tail = _mem_slice_tail.at(i);
     // Get slice in predecessor order (last is first)
     mem_slice_preds(n_tail, n, _nlist);
     // Make the slice dependent on the root
     DepMem* slice = _dg.dep(n);
     _dg.make_edge(_dg.root(), slice);
     // Create a sink for the slice
     DepMem* slice_sink = _dg.make_node(NULL);
     _dg.make_edge(slice_sink, _dg.tail());
     // Now visit each pair of memory ops, creating the edges
     for (int j = _nlist.length() - 1; j >= 0 ; j--) {
       Node* s1 = _nlist.at(j);
       // If no dependency yet, use slice
       if (_dg.dep(s1)->in_cnt() == 0) {
         _dg.make_edge(slice, s1);
       }
       SWPointer p1(s1->as_Mem(), this);
       bool sink_dependent = true;
       for (int k = j - 1; k >= 0; k--) {
         Node* s2 = _nlist.at(k);
         if (s1->is_Load() && s2->is_Load())
           continue;
         SWPointer p2(s2->as_Mem(), this);
         int cmp = p1.cmp(p2);
         if (SuperWordRTDepCheck &&
             p1.base() != p2.base() && p1.valid() && p2.valid()) {
           // Create a runtime check to disambiguate
           OrderedPair pp(p1.base(), p2.base());
           _disjoint_ptrs.append_if_missing(pp);
         } else if (!SWPointer::not_equal(cmp)) {
           // Possibly same address
           _dg.make_edge(s1, s2);
           sink_dependent = false;
         }
       }
       if (sink_dependent) {
         _dg.make_edge(s1, slice_sink);
       }
     }
 #ifndef PRODUCT
     if (TraceSuperWord) {
       tty->print_cr("\nDependence graph for slice: %d", n->_idx);
       for (int q = 0; q < _nlist.length(); q++) {
         _dg.print(_nlist.at(q));
       }
       tty->cr();
     }
 #endif
     _nlist.clear();
   }
 #ifndef PRODUCT
   if (TraceSuperWord) {
     tty->print_cr("\ndisjoint_ptrs: %s", _disjoint_ptrs.length() > 0 ? "" : "NONE");
     for (int r = 0; r < _disjoint_ptrs.length(); r++) {
       _disjoint_ptrs.at(r).print();
       tty->cr();
     }
     tty->cr();
   }
 #endif
 }
 //---------------------------mem_slice_preds---------------------------
 // Return a memory slice (node list) in predecessor order starting at "start"
 void SuperWord::mem_slice_preds(Node* start, Node* stop, GrowableArray<Node*> &preds) {
   assert(preds.length() == 0, "start empty");
   Node* n = start;
   Node* prev = NULL;
   while (true) {
     assert(in_bb(n), "must be in block");
     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
       Node* out = n->fast_out(i);
       if (out->is_Load()) {
         if (in_bb(out)) {
           preds.push(out);
         }
       } else {
         // FIXME
         if (out->is_MergeMem() && !in_bb(out)) {
           // Either unrolling is causing a memory edge not to disappear,
           // or need to run igvn.optimize() again before SLP
         } else if (out->is_Phi() && out->bottom_type() == Type::MEMORY && !in_bb(out)) {
           // Ditto.  Not sure what else to check further.
         } else if (out->Opcode() == Op_StoreCM && out->in(MemNode::OopStore) == n) {
           // StoreCM has an input edge used as a precedence edge.
           // Maybe an issue when oop stores are vectorized.
         } else {
           assert(out == prev || prev == NULL, "no branches off of store slice");
         }
       }
     }
     if (n == stop) break;
     preds.push(n);
     prev = n;
     assert(n->is_Mem(), err_msg_res("unexpected node %s", n->Name()));
     n = n->in(MemNode::Memory);
   }
 }
 //------------------------------stmts_can_pack---------------------------
 // Can s1 and s2 be in a pack with s1 immediately preceding s2 and
 // s1 aligned at "align"
 bool SuperWord::stmts_can_pack(Node* s1, Node* s2, int align) {
   // Do not use superword for non-primitives
   BasicType bt1 = velt_basic_type(s1);
   BasicType bt2 = velt_basic_type(s2);
   if(!is_java_primitive(bt1) || !is_java_primitive(bt2))
     return false;
   if (Matcher::max_vector_size(bt1) < 2) {
     return false; // No vectors for this type
   }
   if (isomorphic(s1, s2)) {
     if (independent(s1, s2)) {
       if (!exists_at(s1, 0) && !exists_at(s2, 1)) {
         if (!s1->is_Mem() || are_adjacent_refs(s1, s2)) {
           int s1_align = alignment(s1);
           int s2_align = alignment(s2);
           if (s1_align == top_align || s1_align == align) {
             if (s2_align == top_align || s2_align == align + data_size(s1)) {
               return true;
             }
           }
         }
       }
     }
   }
   return false;
 }
 //------------------------------exists_at---------------------------
 // Does s exist in a pack at position pos?
 bool SuperWord::exists_at(Node* s, uint pos) {
   for (int i = 0; i < _packset.length(); i++) {
     Node_List* p = _packset.at(i);
     if (p->at(pos) == s) {
       return true;
     }
   }
   return false;
 }
 //------------------------------are_adjacent_refs---------------------------
 // Is s1 immediately before s2 in memory?
 bool SuperWord::are_adjacent_refs(Node* s1, Node* s2) {
   if (!s1->is_Mem() || !s2->is_Mem()) return false;
   if (!in_bb(s1)    || !in_bb(s2))    return false;
   // Do not use superword for non-primitives
   if (!is_java_primitive(s1->as_Mem()->memory_type()) ||
       !is_java_primitive(s2->as_Mem()->memory_type())) {
     return false;
   }
   // FIXME - co_locate_pack fails on Stores in different mem-slices, so
   // only pack memops that are in the same alias set until that's fixed.
   if (_phase->C->get_alias_index(s1->as_Mem()->adr_type()) !=
       _phase->C->get_alias_index(s2->as_Mem()->adr_type()))
     return false;
   SWPointer p1(s1->as_Mem(), this);
   SWPointer p2(s2->as_Mem(), this);
   if (p1.base() != p2.base() || !p1.comparable(p2)) return false;
   int diff = p2.offset_in_bytes() - p1.offset_in_bytes();
   return diff == data_size(s1);
 }
 //------------------------------isomorphic---------------------------
 // Are s1 and s2 similar?
 bool SuperWord::isomorphic(Node* s1, Node* s2) {
   if (s1->Opcode() != s2->Opcode()) return false;
   if (s1->req() != s2->req()) return false;
   if (s1->in(0) != s2->in(0)) return false;
   if (!same_velt_type(s1, s2)) return false;
   return true;
 }
 //------------------------------independent---------------------------
 // Is there no data path from s1 to s2 or s2 to s1?
 bool SuperWord::independent(Node* s1, Node* s2) {
   //  assert(s1->Opcode() == s2->Opcode(), "check isomorphic first");
   int d1 = depth(s1);
   int d2 = depth(s2);
   if (d1 == d2) return s1 != s2;
   Node* deep    = d1 > d2 ? s1 : s2;
   Node* shallow = d1 > d2 ? s2 : s1;
   visited_clear();
   return independent_path(shallow, deep);
 }
 //------------------------------independent_path------------------------------
 // Helper for independent
 bool SuperWord::independent_path(Node* shallow, Node* deep, uint dp) {
   if (dp >= 1000) return false; // stop deep recursion
   visited_set(deep);
   int shal_depth = depth(shallow);
   assert(shal_depth <= depth(deep), "must be");
   for (DepPreds preds(deep, _dg); !preds.done(); preds.next()) {
     Node* pred = preds.current();
     if (in_bb(pred) && !visited_test(pred)) {
       if (shallow == pred) {
         return false;
       }
       if (shal_depth < depth(pred) && !independent_path(shallow, pred, dp+1)) {
         return false;
       }
     }
   }
   return true;
 }
 //------------------------------set_alignment---------------------------
 void SuperWord::set_alignment(Node* s1, Node* s2, int align) {
   set_alignment(s1, align);
   if (align == top_align || align == bottom_align) {
     set_alignment(s2, align);
   } else {
     set_alignment(s2, align + data_size(s1));
   }
 }
 //------------------------------data_size---------------------------
 int SuperWord::data_size(Node* s) {
   int bsize = type2aelembytes(velt_basic_type(s));
   assert(bsize != 0, "valid size");
   return bsize;
 }
 //------------------------------extend_packlist---------------------------
 // Extend packset by following use->def and def->use links from pack members.
 void SuperWord::extend_packlist() {
   bool changed;
   do {
     changed = false;
     for (int i = 0; i < _packset.length(); i++) {
       Node_List* p = _packset.at(i);
       changed |= follow_use_defs(p);
       changed |= follow_def_uses(p);
     }
   } while (changed);
 #ifndef PRODUCT
   if (TraceSuperWord) {
     tty->print_cr("\nAfter extend_packlist");
     print_packset();
   }
 #endif
 }
 //------------------------------follow_use_defs---------------------------
 // Extend the packset by visiting operand definitions of nodes in pack p
 bool SuperWord::follow_use_defs(Node_List* p) {
   assert(p->size() == 2, "just checking");
   Node* s1 = p->at(0);
   Node* s2 = p->at(1);
   assert(s1->req() == s2->req(), "just checking");
   assert(alignment(s1) + data_size(s1) == alignment(s2), "just checking");
   if (s1->is_Load()) return false;
   int align = alignment(s1);
   bool changed = false;
   int start = s1->is_Store() ? MemNode::ValueIn   : 1;
   int end   = s1->is_Store() ? MemNode::ValueIn+1 : s1->req();
   for (int j = start; j < end; j++) {
     Node* t1 = s1->in(j);
     Node* t2 = s2->in(j);
     if (!in_bb(t1) || !in_bb(t2))
       continue;
     if (stmts_can_pack(t1, t2, align)) {
       if (est_savings(t1, t2) >= 0) {
         Node_List* pair = new Node_List();
         pair->push(t1);
         pair->push(t2);
         _packset.append(pair);
         set_alignment(t1, t2, align);
         changed = true;
       }
     }
   }
   return changed;
 }
 //------------------------------follow_def_uses---------------------------
 // Extend the packset by visiting uses of nodes in pack p
 bool SuperWord::follow_def_uses(Node_List* p) {
   bool changed = false;
   Node* s1 = p->at(0);
   Node* s2 = p->at(1);
   assert(p->size() == 2, "just checking");
   assert(s1->req() == s2->req(), "just checking");
   assert(alignment(s1) + data_size(s1) == alignment(s2), "just checking");
   if (s1->is_Store()) return false;
   int align = alignment(s1);
   int savings = -1;
   Node* u1 = NULL;
   Node* u2 = NULL;
   for (DUIterator_Fast imax, i = s1->fast_outs(imax); i < imax; i++) {
     Node* t1 = s1->fast_out(i);
     if (!in_bb(t1)) continue;
     for (DUIterator_Fast jmax, j = s2->fast_outs(jmax); j < jmax; j++) {
       Node* t2 = s2->fast_out(j);
       if (!in_bb(t2)) continue;
       if (!opnd_positions_match(s1, t1, s2, t2))
         continue;
       if (stmts_can_pack(t1, t2, align)) {
         int my_savings = est_savings(t1, t2);
         if (my_savings > savings) {
           savings = my_savings;
           u1 = t1;
           u2 = t2;
         }
       }
     }
   }
   if (savings >= 0) {
     Node_List* pair = new Node_List();
     pair->push(u1);
     pair->push(u2);
     _packset.append(pair);
     set_alignment(u1, u2, align);
     changed = true;
   }
   return changed;
 }
 //---------------------------opnd_positions_match-------------------------
 // Is the use of d1 in u1 at the same operand position as d2 in u2?
 bool SuperWord::opnd_positions_match(Node* d1, Node* u1, Node* d2, Node* u2) {
   uint ct = u1->req();
   if (ct != u2->req()) return false;
   uint i1 = 0;
   uint i2 = 0;
   do {
     for (i1++; i1 < ct; i1++) if (u1->in(i1) == d1) break;
     for (i2++; i2 < ct; i2++) if (u2->in(i2) == d2) break;
     if (i1 != i2) {
       if ((i1 == (3-i2)) && (u2->is_Add() || u2->is_Mul())) {
         // Further analysis relies on operands position matching.
         u2->swap_edges(i1, i2);
       } else {
         return false;
       }
     }
   } while (i1 < ct);
   return true;
 }
 //------------------------------est_savings---------------------------
 // Estimate the savings from executing s1 and s2 as a pack
 int SuperWord::est_savings(Node* s1, Node* s2) {
   int save_in = 2 - 1; // 2 operations per instruction in packed form
   // inputs
   for (uint i = 1; i < s1->req(); i++) {
     Node* x1 = s1->in(i);
     Node* x2 = s2->in(i);
     if (x1 != x2) {
       if (are_adjacent_refs(x1, x2)) {
         save_in += adjacent_profit(x1, x2);
       } else if (!in_packset(x1, x2)) {
         save_in -= pack_cost(2);
       } else {
         save_in += unpack_cost(2);
       }
     }
   }
   // uses of result
   uint ct = 0;
   int save_use = 0;
   for (DUIterator_Fast imax, i = s1->fast_outs(imax); i < imax; i++) {
     Node* s1_use = s1->fast_out(i);
     for (int j = 0; j < _packset.length(); j++) {
       Node_List* p = _packset.at(j);
       if (p->at(0) == s1_use) {
         for (DUIterator_Fast kmax, k = s2->fast_outs(kmax); k < kmax; k++) {
           Node* s2_use = s2->fast_out(k);
           if (p->at(p->size()-1) == s2_use) {
             ct++;
             if (are_adjacent_refs(s1_use, s2_use)) {
               save_use += adjacent_profit(s1_use, s2_use);
             }
           }
         }
       }
     }
   }
   if (ct < s1->outcnt()) save_use += unpack_cost(1);
   if (ct < s2->outcnt()) save_use += unpack_cost(1);
   return MAX2(save_in, save_use);
 }
 //------------------------------costs---------------------------
 int SuperWord::adjacent_profit(Node* s1, Node* s2) { return 2; }
 int SuperWord::pack_cost(int ct)   { return ct; }
 int SuperWord::unpack_cost(int ct) { return ct; }
 //------------------------------combine_packs---------------------------
 // Combine packs A and B with A.last == B.first into A.first..,A.last,B.second,..B.last
 void SuperWord::combine_packs() {
   bool changed = true;
   // Combine packs regardless max vector size.
   while (changed) {
     changed = false;
     for (int i = 0; i < _packset.length(); i++) {
       Node_List* p1 = _packset.at(i);
       if (p1 == NULL) continue;
       for (int j = 0; j < _packset.length(); j++) {
         Node_List* p2 = _packset.at(j);
         if (p2 == NULL) continue;
         if (i == j) continue;
         if (p1->at(p1->size()-1) == p2->at(0)) {
           for (uint k = 1; k < p2->size(); k++) {
             p1->push(p2->at(k));
           }
           _packset.at_put(j, NULL);
           changed = true;
         }
       }
     }
   }
   // Split packs which have size greater then max vector size.
   for (int i = 0; i < _packset.length(); i++) {
     Node_List* p1 = _packset.at(i);
     if (p1 != NULL) {
       BasicType bt = velt_basic_type(p1->at(0));
       uint max_vlen = Matcher::max_vector_size(bt); // Max elements in vector
       assert(is_power_of_2(max_vlen), "sanity");
       uint psize = p1->size();
       if (!is_power_of_2(psize)) {
         // Skip pack which can't be vector.
         // case1: for(...) { a[i] = i; }    elements values are different (i+x)
         // case2: for(...) { a[i] = b[i+1]; }  can't align both, load and store
         _packset.at_put(i, NULL);
         continue;
       }
       if (psize > max_vlen) {
         Node_List* pack = new Node_List();
         for (uint j = 0; j < psize; j++) {
           pack->push(p1->at(j));
           if (pack->size() >= max_vlen) {
             assert(is_power_of_2(pack->size()), "sanity");
             _packset.append(pack);
             pack = new Node_List();
           }
         }
         _packset.at_put(i, NULL);
       }
     }
   }
   // Compress list.
   for (int i = _packset.length() - 1; i >= 0; i--) {
     Node_List* p1 = _packset.at(i);
     if (p1 == NULL) {
       _packset.remove_at(i);
     }
   }
 #ifndef PRODUCT
   if (TraceSuperWord) {
     tty->print_cr("\nAfter combine_packs");
     print_packset();
   }
 #endif
 }
 //-----------------------------construct_my_pack_map--------------------------
 // Construct the map from nodes to packs.  Only valid after the
 // point where a node is only in one pack (after combine_packs).
 void SuperWord::construct_my_pack_map() {
   Node_List* rslt = NULL;
   for (int i = 0; i < _packset.length(); i++) {
     Node_List* p = _packset.at(i);
     for (uint j = 0; j < p->size(); j++) {
       Node* s = p->at(j);
       assert(my_pack(s) == NULL, "only in one pack");
       set_my_pack(s, p);
     }
   }
 }
 //------------------------------filter_packs---------------------------
 // Remove packs that are not implemented or not profitable.
 void SuperWord::filter_packs() {
   // Remove packs that are not implemented
   for (int i = _packset.length() - 1; i >= 0; i--) {
     Node_List* pk = _packset.at(i);
     bool impl = implemented(pk);
     if (!impl) {
 #ifndef PRODUCT
       if (TraceSuperWord && Verbose) {
         tty->print_cr("Unimplemented");
         pk->at(0)->dump();
       }
 #endif
       remove_pack_at(i);
     }
   }
   // Remove packs that are not profitable
   bool changed;
   do {
     changed = false;
     for (int i = _packset.length() - 1; i >= 0; i--) {
       Node_List* pk = _packset.at(i);
       bool prof = profitable(pk);
       if (!prof) {
 #ifndef PRODUCT
         if (TraceSuperWord && Verbose) {
           tty->print_cr("Unprofitable");
           pk->at(0)->dump();
         }
 #endif
         remove_pack_at(i);
         changed = true;
       }
     }
   } while (changed);
 #ifndef PRODUCT
   if (TraceSuperWord) {
     tty->print_cr("\nAfter filter_packs");
     print_packset();
     tty->cr();
   }
 #endif
 }
 //------------------------------implemented---------------------------
 // Can code be generated for pack p?
 bool SuperWord::implemented(Node_List* p) {
   Node* p0 = p->at(0);
   return VectorNode::implemented(p0->Opcode(), p->size(), velt_basic_type(p0));
 }
 //------------------------------same_inputs--------------------------
 // For pack p, are all idx operands the same?
 static bool same_inputs(Node_List* p, int idx) {
   Node* p0 = p->at(0);
   uint vlen = p->size();
   Node* p0_def = p0->in(idx);
   for (uint i = 1; i < vlen; i++) {
     Node* pi = p->at(i);
     Node* pi_def = pi->in(idx);
     if (p0_def != pi_def)
       return false;
   }
   return true;
 }
 //------------------------------profitable---------------------------
 // For pack p, are all operands and all uses (with in the block) vector?
 bool SuperWord::profitable(Node_List* p) {
   Node* p0 = p->at(0);
   uint start, end;
   VectorNode::vector_operands(p0, &start, &end);
   // Return false if some inputs are not vectors or vectors with different
   // size or alignment.
   // Also, for now, return false if not scalar promotion case when inputs are
   // the same. Later, implement PackNode and allow differing, non-vector inputs
   // (maybe just the ones from outside the block.)
   for (uint i = start; i < end; i++) {
     if (!is_vector_use(p0, i))
       return false;
   }
   if (VectorNode::is_shift(p0)) {
     // For now, return false if shift count is vector or not scalar promotion
     // case (different shift counts) because it is not supported yet.
     Node* cnt = p0->in(2);
     Node_List* cnt_pk = my_pack(cnt);
     if (cnt_pk != NULL)
       return false;
     if (!same_inputs(p, 2))
       return false;
   }
   if (!p0->is_Store()) {
     // For now, return false if not all uses are vector.
     // Later, implement ExtractNode and allow non-vector uses (maybe
     // just the ones outside the block.)
     for (uint i = 0; i < p->size(); i++) {
       Node* def = p->at(i);
       for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
         Node* use = def->fast_out(j);
         for (uint k = 0; k < use->req(); k++) {
           Node* n = use->in(k);
           if (def == n) {
             if (!is_vector_use(use, k)) {
               return false;
             }
           }
         }
       }
     }
   }
   return true;
 }
 //------------------------------schedule---------------------------
 // Adjust the memory graph for the packed operations
 void SuperWord::schedule() {
   // Co-locate in the memory graph the members of each memory pack
   for (int i = 0; i < _packset.length(); i++) {
     co_locate_pack(_packset.at(i));
   }
 }
 //-------------------------------remove_and_insert-------------------
 // Remove "current" from its current position in the memory graph and insert
 // it after the appropriate insertion point (lip or uip).
 void SuperWord::remove_and_insert(MemNode *current, MemNode *prev, MemNode *lip,
                                   Node *uip, Unique_Node_List &sched_before) {
   Node* my_mem = current->in(MemNode::Memory);
   bool sched_up = sched_before.member(current);
   // remove current_store from its current position in the memmory graph
   for (DUIterator i = current->outs(); current->has_out(i); i++) {
     Node* use = current->out(i);
     if (use->is_Mem()) {
       assert(use->in(MemNode::Memory) == current, "must be");
       if (use == prev) { // connect prev to my_mem
           _igvn.replace_input_of(use, MemNode::Memory, my_mem);
           --i; //deleted this edge; rescan position
       } else if (sched_before.member(use)) {
         if (!sched_up) { // Will be moved together with current
           _igvn.replace_input_of(use, MemNode::Memory, uip);
           --i; //deleted this edge; rescan position
         }
       } else {
         if (sched_up) { // Will be moved together with current
           _igvn.replace_input_of(use, MemNode::Memory, lip);
           --i; //deleted this edge; rescan position
         }
       }
     }
   }
   Node *insert_pt =  sched_up ?  uip : lip;
   // all uses of insert_pt's memory state should use current's instead
   for (DUIterator i = insert_pt->outs(); insert_pt->has_out(i); i++) {
     Node* use = insert_pt->out(i);
     if (use->is_Mem()) {
       assert(use->in(MemNode::Memory) == insert_pt, "must be");
       _igvn.replace_input_of(use, MemNode::Memory, current);
       --i; //deleted this edge; rescan position
     } else if (!sched_up && use->is_Phi() && use->bottom_type() == Type::MEMORY) {
       uint pos; //lip (lower insert point) must be the last one in the memory slice
       for (pos=1; pos < use->req(); pos++) {
         if (use->in(pos) == insert_pt) break;
       }
       _igvn.replace_input_of(use, pos, current);
       --i;
     }
   }
   //connect current to insert_pt
   _igvn.replace_input_of(current, MemNode::Memory, insert_pt);
 }
 //------------------------------co_locate_pack----------------------------------
 // To schedule a store pack, we need to move any sandwiched memory ops either before
 // or after the pack, based upon dependence information:
 // (1) If any store in the pack depends on the sandwiched memory op, the
 //     sandwiched memory op must be scheduled BEFORE the pack;
 // (2) If a sandwiched memory op depends on any store in the pack, the
 //     sandwiched memory op must be scheduled AFTER the pack;
 // (3) If a sandwiched memory op (say, memA) depends on another sandwiched
 //     memory op (say memB), memB must be scheduled before memA. So, if memA is
 //     scheduled before the pack, memB must also be scheduled before the pack;
 // (4) If there is no dependence restriction for a sandwiched memory op, we simply
 //     schedule this store AFTER the pack
 // (5) We know there is no dependence cycle, so there in no other case;
 // (6) Finally, all memory ops in another single pack should be moved in the same direction.
 //
 // To schedule a load pack, we use the memory state of either the first or the last load in
 // the pack, based on the dependence constraint.
 void SuperWord::co_locate_pack(Node_List* pk) {
   if (pk->at(0)->is_Store()) {
     MemNode* first     = executed_first(pk)->as_Mem();
     MemNode* last      = executed_last(pk)->as_Mem();
     Unique_Node_List schedule_before_pack;
     Unique_Node_List memops;
     MemNode* current   = last->in(MemNode::Memory)->as_Mem();
     MemNode* previous  = last;
     while (true) {
       assert(in_bb(current), "stay in block");
       memops.push(previous);
       for (DUIterator i = current->outs(); current->has_out(i); i++) {
         Node* use = current->out(i);
         if (use->is_Mem() && use != previous)
           memops.push(use);
       }
       if (current == first) break;
       previous = current;
       current  = current->in(MemNode::Memory)->as_Mem();
     }
     // determine which memory operations should be scheduled before the pack
     for (uint i = 1; i < memops.size(); i++) {
       Node *s1 = memops.at(i);
       if (!in_pack(s1, pk) && !schedule_before_pack.member(s1)) {
         for (uint j = 0; j< i; j++) {
           Node *s2 = memops.at(j);
           if (!independent(s1, s2)) {
             if (in_pack(s2, pk) || schedule_before_pack.member(s2)) {
               schedule_before_pack.push(s1); // s1 must be scheduled before
               Node_List* mem_pk = my_pack(s1);
               if (mem_pk != NULL) {
                 for (uint ii = 0; ii < mem_pk->size(); ii++) {
                   Node* s = mem_pk->at(ii);  // follow partner
                   if (memops.member(s) && !schedule_before_pack.member(s))
                     schedule_before_pack.push(s);
                 }
               }
               break;
             }
           }
         }
       }
     }
     Node*    upper_insert_pt = first->in(MemNode::Memory);
     // Following code moves loads connected to upper_insert_pt below aliased stores.
     // Collect such loads here and reconnect them back to upper_insert_pt later.
     memops.clear();
     for (DUIterator i = upper_insert_pt->outs(); upper_insert_pt->has_out(i); i++) {
       Node* use = upper_insert_pt->out(i);
       if (use->is_Mem() && !use->is_Store()) {
         memops.push(use);
       }
     }
     MemNode* lower_insert_pt = last;
     previous                 = last; //previous store in pk
     current                  = last->in(MemNode::Memory)->as_Mem();
     // start scheduling from "last" to "first"
     while (true) {
       assert(in_bb(current), "stay in block");
       assert(in_pack(previous, pk), "previous stays in pack");
       Node* my_mem = current->in(MemNode::Memory);
       if (in_pack(current, pk)) {
         // Forward users of my memory state (except "previous) to my input memory state
         for (DUIterator i = current->outs(); current->has_out(i); i++) {
           Node* use = current->out(i);
           if (use->is_Mem() && use != previous) {
             assert(use->in(MemNode::Memory) == current, "must be");
             if (schedule_before_pack.member(use)) {
               _igvn.replace_input_of(use, MemNode::Memory, upper_insert_pt);
             } else {
               _igvn.replace_input_of(use, MemNode::Memory, lower_insert_pt);
             }
             --i; // deleted this edge; rescan position
           }
         }
         previous = current;
       } else { // !in_pack(current, pk) ==> a sandwiched store
         remove_and_insert(current, previous, lower_insert_pt, upper_insert_pt, schedule_before_pack);
       }
       if (current == first) break;
       current = my_mem->as_Mem();
     } // end while
     // Reconnect loads back to upper_insert_pt.
     for (uint i = 0; i < memops.size(); i++) {
       Node *ld = memops.at(i);
       if (ld->in(MemNode::Memory) != upper_insert_pt) {
         _igvn.replace_input_of(ld, MemNode::Memory, upper_insert_pt);
       }
     }
   } else if (pk->at(0)->is_Load()) { //load
     // all loads in the pack should have the same memory state. By default,
     // we use the memory state of the last load. However, if any load could
     // not be moved down due to the dependence constraint, we use the memory
     // state of the first load.
     Node* last_mem  = executed_last(pk)->in(MemNode::Memory);
     Node* first_mem = executed_first(pk)->in(MemNode::Memory);
     bool schedule_last = true;
     for (uint i = 0; i < pk->size(); i++) {
       Node* ld = pk->at(i);
       for (Node* current = last_mem; current != ld->in(MemNode::Memory);
            current=current->in(MemNode::Memory)) {
         assert(current != first_mem, "corrupted memory graph");
         if(current->is_Mem() && !independent(current, ld)){
           schedule_last = false; // a later store depends on this load
           break;
         }
       }
     }
     Node* mem_input = schedule_last ? last_mem : first_mem;
     _igvn.hash_delete(mem_input);
     // Give each load the same memory state
     for (uint i = 0; i < pk->size(); i++) {
       LoadNode* ld = pk->at(i)->as_Load();
       _igvn.replace_input_of(ld, MemNode::Memory, mem_input);
     }
   }
 }
 //------------------------------output---------------------------
 // Convert packs into vector node operations
 void SuperWord::output() {
   if (_packset.length() == 0) return;
 #ifndef PRODUCT
   if (TraceLoopOpts) {
     tty->print("SuperWord    ");
     lpt()->dump_head();
   }
 #endif
   // MUST ENSURE main loop's initial value is properly aligned:
   //  (iv_initial_value + min_iv_offset) % vector_width_in_bytes() == 0
   align_initial_loop_index(align_to_ref());
   // Insert extract (unpack) operations for scalar uses
   for (int i = 0; i < _packset.length(); i++) {
     insert_extracts(_packset.at(i));
   }
   Compile* C = _phase->C;
   uint max_vlen_in_bytes = 0;
   for (int i = 0; i < _block.length(); i++) {
     Node* n = _block.at(i);
     Node_List* p = my_pack(n);
     if (p && n == executed_last(p)) {
       uint vlen = p->size();
       uint vlen_in_bytes = 0;
       Node* vn = NULL;
       Node* low_adr = p->at(0);
       Node* first   = executed_first(p);
       int   opc = n->Opcode();
       if (n->is_Load()) {
         Node* ctl = n->in(MemNode::Control);
         Node* mem = first->in(MemNode::Memory);
         SWPointer p1(n->as_Mem(), this);
         // Identify the memory dependency for the new loadVector node by
         // walking up through memory chain.
         // This is done to give flexibility to the new loadVector node so that
         // it can move above independent storeVector nodes.
         while (mem->is_StoreVector()) {
           SWPointer p2(mem->as_Mem(), this);
           int cmp = p1.cmp(p2);
           if (SWPointer::not_equal(cmp) || !SWPointer::comparable(cmp)) {
             mem = mem->in(MemNode::Memory);
           } else {
             break; // dependent memory
           }
         }
         Node* adr = low_adr->in(MemNode::Address);
         const TypePtr* atyp = n->adr_type();
         vn = LoadVectorNode::make(C, opc, ctl, mem, adr, atyp, vlen, velt_basic_type(n), control_dependency(p));
         vlen_in_bytes = vn->as_LoadVector()->memory_size();
       } else if (n->is_Store()) {
         // Promote value to be stored to vector
         Node* val = vector_opd(p, MemNode::ValueIn);
         Node* ctl = n->in(MemNode::Control);
         Node* mem = first->in(MemNode::Memory);
         Node* adr = low_adr->in(MemNode::Address);
         const TypePtr* atyp = n->adr_type();
         vn = StoreVectorNode::make(C, opc, ctl, mem, adr, atyp, val, vlen);
         vlen_in_bytes = vn->as_StoreVector()->memory_size();
       } else if (n->req() == 3) {
         // Promote operands to vector
         Node* in1 = vector_opd(p, 1);
         Node* in2 = vector_opd(p, 2);
         if (VectorNode::is_invariant_vector(in1) && (n->is_Add() || n->is_Mul())) {
           // Move invariant vector input into second position to avoid register spilling.
           Node* tmp = in1;
           in1 = in2;
           in2 = tmp;
         }
         vn = VectorNode::make(C, opc, in1, in2, vlen, velt_basic_type(n));
         vlen_in_bytes = vn->as_Vector()->length_in_bytes();
       } else {
         ShouldNotReachHere();
       }
       assert(vn != NULL, "sanity");
       _igvn.register_new_node_with_optimizer(vn);
       _phase->set_ctrl(vn, _phase->get_ctrl(p->at(0)));
       for (uint j = 0; j < p->size(); j++) {
         Node* pm = p->at(j);
         _igvn.replace_node(pm, vn);
       }
       _igvn._worklist.push(vn);
       if (vlen_in_bytes > max_vlen_in_bytes) {
         max_vlen_in_bytes = vlen_in_bytes;
       }
 #ifdef ASSERT
       if (TraceNewVectors) {
         tty->print("new Vector node: ");
         vn->dump();
       }
 #endif
     }
   }
   C->set_max_vector_size(max_vlen_in_bytes);
 }
 //------------------------------vector_opd---------------------------
 // Create a vector operand for the nodes in pack p for operand: in(opd_idx)
 Node* SuperWord::vector_opd(Node_List* p, int opd_idx) {
   Node* p0 = p->at(0);
   uint vlen = p->size();
   Node* opd = p0->in(opd_idx);
   if (same_inputs(p, opd_idx)) {
     if (opd->is_Vector() || opd->is_LoadVector()) {
       assert(((opd_idx != 2) || !VectorNode::is_shift(p0)), "shift's count can't be vector");
       return opd; // input is matching vector
     }
     if ((opd_idx == 2) && VectorNode::is_shift(p0)) {
       Compile* C = _phase->C;
       Node* cnt = opd;
       // Vector instructions do not mask shift count, do it here.
       juint mask = (p0->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
       const TypeInt* t = opd->find_int_type();
       if (t != NULL && t->is_con()) {
         juint shift = t->get_con();
         if (shift > mask) { // Unsigned cmp
           cnt = ConNode::make(C, TypeInt::make(shift & mask));
         }
       } else {
         if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
           cnt = ConNode::make(C, TypeInt::make(mask));
           _igvn.register_new_node_with_optimizer(cnt);
           cnt = new (C) AndINode(opd, cnt);
           _igvn.register_new_node_with_optimizer(cnt);
           _phase->set_ctrl(cnt, _phase->get_ctrl(opd));
         }
         assert(opd->bottom_type()->isa_int(), "int type only");
         // Move non constant shift count into vector register.
         cnt = VectorNode::shift_count(C, p0, cnt, vlen, velt_basic_type(p0));
       }
       if (cnt != opd) {
         _igvn.register_new_node_with_optimizer(cnt);
         _phase->set_ctrl(cnt, _phase->get_ctrl(opd));
       }
       return cnt;
     }
     assert(!opd->is_StoreVector(), "such vector is not expected here");
     // Convert scalar input to vector with the same number of elements as
     // p0's vector. Use p0's type because size of operand's container in
     // vector should match p0's size regardless operand's size.
     const Type* p0_t = velt_type(p0);
     VectorNode* vn = VectorNode::scalar2vector(_phase->C, opd, vlen, p0_t);
     _igvn.register_new_node_with_optimizer(vn);
     _phase->set_ctrl(vn, _phase->get_ctrl(opd));
 #ifdef ASSERT
     if (TraceNewVectors) {
       tty->print("new Vector node: ");
       vn->dump();
     }
 #endif
     return vn;
   }
   // Insert pack operation
   BasicType bt = velt_basic_type(p0);
   PackNode* pk = PackNode::make(_phase->C, opd, vlen, bt);
   DEBUG_ONLY( const BasicType opd_bt = opd->bottom_type()->basic_type(); )
   for (uint i = 1; i < vlen; i++) {
     Node* pi = p->at(i);
     Node* in = pi->in(opd_idx);
     assert(my_pack(in) == NULL, "Should already have been unpacked");
     assert(opd_bt == in->bottom_type()->basic_type(), "all same type");
     pk->add_opd(in);
   }
   _igvn.register_new_node_with_optimizer(pk);
   _phase->set_ctrl(pk, _phase->get_ctrl(opd));
 #ifdef ASSERT
   if (TraceNewVectors) {
     tty->print("new Vector node: ");
     pk->dump();
   }
 #endif
   return pk;
 }
 //------------------------------insert_extracts---------------------------
 // If a use of pack p is not a vector use, then replace the
 // use with an extract operation.
 void SuperWord::insert_extracts(Node_List* p) {
   if (p->at(0)->is_Store()) return;
   assert(_n_idx_list.is_empty(), "empty (node,index) list");
   // Inspect each use of each pack member.  For each use that is
   // not a vector use, replace the use with an extract operation.
   for (uint i = 0; i < p->size(); i++) {
     Node* def = p->at(i);
     for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
       Node* use = def->fast_out(j);
       for (uint k = 0; k < use->req(); k++) {
         Node* n = use->in(k);
         if (def == n) {
           if (!is_vector_use(use, k)) {
             _n_idx_list.push(use, k);
           }
         }
       }
     }
   }
   while (_n_idx_list.is_nonempty()) {
     Node* use = _n_idx_list.node();
     int   idx = _n_idx_list.index();
     _n_idx_list.pop();
     Node* def = use->in(idx);
     // Insert extract operation
     _igvn.hash_delete(def);
     int def_pos = alignment(def) / data_size(def);
     Node* ex = ExtractNode::make(_phase->C, def, def_pos, velt_basic_type(def));
     _igvn.register_new_node_with_optimizer(ex);
     _phase->set_ctrl(ex, _phase->get_ctrl(def));
     _igvn.replace_input_of(use, idx, ex);
     _igvn._worklist.push(def);
     bb_insert_after(ex, bb_idx(def));
     set_velt_type(ex, velt_type(def));
   }
 }
 //------------------------------is_vector_use---------------------------
 // Is use->in(u_idx) a vector use?
 bool SuperWord::is_vector_use(Node* use, int u_idx) {
   Node_List* u_pk = my_pack(use);
   if (u_pk == NULL) return false;
   Node* def = use->in(u_idx);
   Node_List* d_pk = my_pack(def);
   if (d_pk == NULL) {
     // check for scalar promotion
     Node* n = u_pk->at(0)->in(u_idx);
     for (uint i = 1; i < u_pk->size(); i++) {
       if (u_pk->at(i)->in(u_idx) != n) return false;
     }
     return true;
   }
   if (u_pk->size() != d_pk->size())
     return false;
   for (uint i = 0; i < u_pk->size(); i++) {
     Node* ui = u_pk->at(i);
     Node* di = d_pk->at(i);
     if (ui->in(u_idx) != di || alignment(ui) != alignment(di))
       return false;
   }
   return true;
 }
 //------------------------------construct_bb---------------------------
 // Construct reverse postorder list of block members
 bool SuperWord::construct_bb() {
   Node* entry = bb();
   assert(_stk.length() == 0,            "stk is empty");
   assert(_block.length() == 0,          "block is empty");
   assert(_data_entry.length() == 0,     "data_entry is empty");
   assert(_mem_slice_head.length() == 0, "mem_slice_head is empty");
   assert(_mem_slice_tail.length() == 0, "mem_slice_tail is empty");
   // Find non-control nodes with no inputs from within block,
   // create a temporary map from node _idx to bb_idx for use
   // by the visited and post_visited sets,
   // and count number of nodes in block.
   int bb_ct = 0;
   for (uint i = 0; i < lpt()->_body.size(); i++ ) {
     Node *n = lpt()->_body.at(i);
     set_bb_idx(n, i); // Create a temporary map
     if (in_bb(n)) {
       if (n->is_LoadStore() || n->is_MergeMem() ||
           (n->is_Proj() && !n->as_Proj()->is_CFG())) {
         // Bailout if the loop has LoadStore, MergeMem or data Proj
         // nodes. Superword optimization does not work with them.
         return false;
       }
       bb_ct++;
       if (!n->is_CFG()) {
         bool found = false;
         for (uint j = 0; j < n->req(); j++) {
           Node* def = n->in(j);
           if (def && in_bb(def)) {
             found = true;
             break;
           }
         }
         if (!found) {
           assert(n != entry, "can't be entry");
           _data_entry.push(n);
         }
       }
     }
   }
   // Find memory slices (head and tail)
   for (DUIterator_Fast imax, i = lp()->fast_outs(imax); i < imax; i++) {
     Node *n = lp()->fast_out(i);
     if (in_bb(n) && (n->is_Phi() && n->bottom_type() == Type::MEMORY)) {
       Node* n_tail  = n->in(LoopNode::LoopBackControl);
       if (n_tail != n->in(LoopNode::EntryControl)) {
         if (!n_tail->is_Mem()) {
           assert(n_tail->is_Mem(), err_msg_res("unexpected node for memory slice: %s", n_tail->Name()));
           return false; // Bailout
         }
         _mem_slice_head.push(n);
         _mem_slice_tail.push(n_tail);
       }
     }
   }
   // Create an RPO list of nodes in block
   visited_clear();
   post_visited_clear();
   // Push all non-control nodes with no inputs from within block, then control entry
   for (int j = 0; j < _data_entry.length(); j++) {
     Node* n = _data_entry.at(j);
     visited_set(n);
     _stk.push(n);
   }
   visited_set(entry);
   _stk.push(entry);
   // Do a depth first walk over out edges
   int rpo_idx = bb_ct - 1;
   int size;
   while ((size = _stk.length()) > 0) {
     Node* n = _stk.top(); // Leave node on stack
     if (!visited_test_set(n)) {
       // forward arc in graph
     } else if (!post_visited_test(n)) {
       // cross or back arc
       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
         Node *use = n->fast_out(i);
         if (in_bb(use) && !visited_test(use) &&
             // Don't go around backedge
             (!use->is_Phi() || n == entry)) {
           _stk.push(use);
         }
       }
       if (_stk.length() == size) {
         // There were no additional uses, post visit node now
         _stk.pop(); // Remove node from stack
         assert(rpo_idx >= 0, "");
         _block.at_put_grow(rpo_idx, n);
         rpo_idx--;
         post_visited_set(n);
         assert(rpo_idx >= 0 || _stk.is_empty(), "");
       }
     } else {
       _stk.pop(); // Remove post-visited node from stack
     }
   }
   // Create real map of block indices for nodes
   for (int j = 0; j < _block.length(); j++) {
     Node* n = _block.at(j);
     set_bb_idx(n, j);
   }
   initialize_bb(); // Ensure extra info is allocated.
 #ifndef PRODUCT
   if (TraceSuperWord) {
     print_bb();
     tty->print_cr("\ndata entry nodes: %s", _data_entry.length() > 0 ? "" : "NONE");
     for (int m = 0; m < _data_entry.length(); m++) {
       tty->print("%3d ", m);
       _data_entry.at(m)->dump();
     }
     tty->print_cr("\nmemory slices: %s", _mem_slice_head.length() > 0 ? "" : "NONE");
     for (int m = 0; m < _mem_slice_head.length(); m++) {
       tty->print("%3d ", m); _mem_slice_head.at(m)->dump();
       tty->print("    ");    _mem_slice_tail.at(m)->dump();
     }
   }
 #endif
   assert(rpo_idx == -1 && bb_ct == _block.length(), "all block members found");
   return (_mem_slice_head.length() > 0) || (_data_entry.length() > 0);
 }
 //------------------------------initialize_bb---------------------------
 // Initialize per node info
 void SuperWord::initialize_bb() {
   Node* last = _block.at(_block.length() - 1);
   grow_node_info(bb_idx(last));
 }
 //------------------------------bb_insert_after---------------------------
 // Insert n into block after pos
 void SuperWord::bb_insert_after(Node* n, int pos) {
   int n_pos = pos + 1;
   // Make room
   for (int i = _block.length() - 1; i >= n_pos; i--) {
     _block.at_put_grow(i+1, _block.at(i));
   }
   for (int j = _node_info.length() - 1; j >= n_pos; j--) {
     _node_info.at_put_grow(j+1, _node_info.at(j));
   }
   // Set value
   _block.at_put_grow(n_pos, n);
   _node_info.at_put_grow(n_pos, SWNodeInfo::initial);
   // Adjust map from node->_idx to _block index
   for (int i = n_pos; i < _block.length(); i++) {
     set_bb_idx(_block.at(i), i);
   }
 }
 //------------------------------compute_max_depth---------------------------
 // Compute max depth for expressions from beginning of block
 // Use to prune search paths during test for independence.
 void SuperWord::compute_max_depth() {
   int ct = 0;
   bool again;
   do {
     again = false;
     for (int i = 0; i < _block.length(); i++) {
       Node* n = _block.at(i);
       if (!n->is_Phi()) {
         int d_orig = depth(n);
         int d_in   = 0;
         for (DepPreds preds(n, _dg); !preds.done(); preds.next()) {
           Node* pred = preds.current();
           if (in_bb(pred)) {
             d_in = MAX2(d_in, depth(pred));
           }
         }
         if (d_in + 1 != d_orig) {
           set_depth(n, d_in + 1);
           again = true;
         }
       }
     }
     ct++;
   } while (again);
 #ifndef PRODUCT
   if (TraceSuperWord && Verbose)
     tty->print_cr("compute_max_depth iterated: %d times", ct);
 #endif
 }
 //-------------------------compute_vector_element_type-----------------------
 // Compute necessary vector element type for expressions
 // This propagates backwards a narrower integer type when the
 // upper bits of the value are not needed.
 // Example:  char a,b,c;  a = b + c;
 // Normally the type of the add is integer, but for packed character
 // operations the type of the add needs to be char.
 void SuperWord::compute_vector_element_type() {
 #ifndef PRODUCT
   if (TraceSuperWord && Verbose)
     tty->print_cr("\ncompute_velt_type:");
 #endif
   // Initial type
   for (int i = 0; i < _block.length(); i++) {
     Node* n = _block.at(i);
     set_velt_type(n, container_type(n));
   }
   // Propagate integer narrowed type backwards through operations
   // that don't depend on higher order bits
   for (int i = _block.length() - 1; i >= 0; i--) {
     Node* n = _block.at(i);
     // Only integer types need be examined
     const Type* vtn = velt_type(n);
     if (vtn->basic_type() == T_INT) {
       uint start, end;
       VectorNode::vector_operands(n, &start, &end);
       for (uint j = start; j < end; j++) {
         Node* in  = n->in(j);
         // Don't propagate through a memory
         if (!in->is_Mem() && in_bb(in) && velt_type(in)->basic_type() == T_INT &&
             data_size(n) < data_size(in)) {
           bool same_type = true;
           for (DUIterator_Fast kmax, k = in->fast_outs(kmax); k < kmax; k++) {
             Node *use = in->fast_out(k);
             if (!in_bb(use) || !same_velt_type(use, n)) {
               same_type = false;
               break;
             }
           }
           if (same_type) {
             // For right shifts of small integer types (bool, byte, char, short)
             // we need precise information about sign-ness. Only Load nodes have
             // this information because Store nodes are the same for signed and
             // unsigned values. And any arithmetic operation after a load may
             // expand a value to signed Int so such right shifts can't be used
             // because vector elements do not have upper bits of Int.
             const Type* vt = vtn;
             if (VectorNode::is_shift(in)) {
               Node* load = in->in(1);
               if (load->is_Load() && in_bb(load) && (velt_type(load)->basic_type() == T_INT)) {
                 vt = velt_type(load);
               } else if (in->Opcode() != Op_LShiftI) {
                 // Widen type to Int to avoid creation of right shift vector
                 // (align + data_size(s1) check in stmts_can_pack() will fail).
                 // Note, left shifts work regardless type.
                 vt = TypeInt::INT;
               }
             }
             set_velt_type(in, vt);
           }
         }
       }
     }
   }
 #ifndef PRODUCT
   if (TraceSuperWord && Verbose) {
     for (int i = 0; i < _block.length(); i++) {
       Node* n = _block.at(i);
       velt_type(n)->dump();
       tty->print("\t");
       n->dump();
     }
   }
 #endif
 }
 //------------------------------memory_alignment---------------------------
 // Alignment within a vector memory reference
 int SuperWord::memory_alignment(MemNode* s, int iv_adjust) {
   SWPointer p(s, this);
   if (!p.valid()) {
     return bottom_align;
   }
   int vw = vector_width_in_bytes(s);
   if (vw < 2) {
     return bottom_align; // No vectors for this type
   }
   int offset  = p.offset_in_bytes();
   offset     += iv_adjust*p.memory_size();
   int off_rem = offset % vw;
   int off_mod = off_rem >= 0 ? off_rem : off_rem + vw;
   return off_mod;
 }
 //---------------------------container_type---------------------------
 // Smallest type containing range of values
 const Type* SuperWord::container_type(Node* n) {
   if (n->is_Mem()) {
     BasicType bt = n->as_Mem()->memory_type();
     if (n->is_Store() && (bt == T_CHAR)) {
       // Use T_SHORT type instead of T_CHAR for stored values because any
       // preceding arithmetic operation extends values to signed Int.
       bt = T_SHORT;
     }
     if (n->Opcode() == Op_LoadUB) {
       // Adjust type for unsigned byte loads, it is important for right shifts.
       // T_BOOLEAN is used because there is no basic type representing type
       // TypeInt::UBYTE. Use of T_BOOLEAN for vectors is fine because only
       // size (one byte) and sign is important.
       bt = T_BOOLEAN;
     }
     return Type::get_const_basic_type(bt);
   }
   const Type* t = _igvn.type(n);
   if (t->basic_type() == T_INT) {
     // A narrow type of arithmetic operations will be determined by
     // propagating the type of memory operations.
     return TypeInt::INT;
   }
   return t;
 }
 bool SuperWord::same_velt_type(Node* n1, Node* n2) {
   const Type* vt1 = velt_type(n1);
   const Type* vt2 = velt_type(n2);
   if (vt1->basic_type() == T_INT && vt2->basic_type() == T_INT) {
     // Compare vectors element sizes for integer types.
     return data_size(n1) == data_size(n2);
   }
   return vt1 == vt2;
 }
 //------------------------------in_packset---------------------------
 // Are s1 and s2 in a pack pair and ordered as s1,s2?
 bool SuperWord::in_packset(Node* s1, Node* s2) {
   for (int i = 0; i < _packset.length(); i++) {
     Node_List* p = _packset.at(i);
     assert(p->size() == 2, "must be");
     if (p->at(0) == s1 && p->at(p->size()-1) == s2) {
       return true;
     }
   }
   return false;
 }
 //------------------------------in_pack---------------------------
 // Is s in pack p?
 Node_List* SuperWord::in_pack(Node* s, Node_List* p) {
   for (uint i = 0; i < p->size(); i++) {
     if (p->at(i) == s) {
       return p;
     }
   }
   return NULL;
 }
 //------------------------------remove_pack_at---------------------------
 // Remove the pack at position pos in the packset
 void SuperWord::remove_pack_at(int pos) {
   Node_List* p = _packset.at(pos);
   for (uint i = 0; i < p->size(); i++) {
     Node* s = p->at(i);
     set_my_pack(s, NULL);
   }
   _packset.remove_at(pos);
 }
 //------------------------------executed_first---------------------------
 // Return the node executed first in pack p.  Uses the RPO block list
 // to determine order.
 Node* SuperWord::executed_first(Node_List* p) {
   Node* n = p->at(0);
   int n_rpo = bb_idx(n);
   for (uint i = 1; i < p->size(); i++) {
     Node* s = p->at(i);
     int s_rpo = bb_idx(s);
     if (s_rpo < n_rpo) {
       n = s;
       n_rpo = s_rpo;
     }
   }
   return n;
 }
 //------------------------------executed_last---------------------------
 // Return the node executed last in pack p.
 Node* SuperWord::executed_last(Node_List* p) {
   Node* n = p->at(0);
   int n_rpo = bb_idx(n);
   for (uint i = 1; i < p->size(); i++) {
     Node* s = p->at(i);
     int s_rpo = bb_idx(s);
     if (s_rpo > n_rpo) {
       n = s;
       n_rpo = s_rpo;
     }
   }
   return n;
 }
 LoadNode::ControlDependency SuperWord::control_dependency(Node_List* p) {
   LoadNode::ControlDependency dep = LoadNode::DependsOnlyOnTest;
   for (uint i = 0; i < p->size(); i++) {
     Node* n = p->at(i);
     assert(n->is_Load(), "only meaningful for loads");
     if (!n->depends_only_on_test()) {
       dep = LoadNode::Pinned;
     }
   }
   return dep;
 }
 //----------------------------align_initial_loop_index---------------------------
 // Adjust pre-loop limit so that in main loop, a load/store reference
 // to align_to_ref will be a position zero in the vector.
 //   (iv + k) mod vector_align == 0
 void SuperWord::align_initial_loop_index(MemNode* align_to_ref) {
   CountedLoopNode *main_head = lp()->as_CountedLoop();
   assert(main_head->is_main_loop(), "");
   CountedLoopEndNode* pre_end = get_pre_loop_end(main_head);
   assert(pre_end != NULL, "we must have a correct pre-loop");
   Node *pre_opaq1 = pre_end->limit();
   assert(pre_opaq1->Opcode() == Op_Opaque1, "");
   Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1;
   Node *lim0 = pre_opaq->in(1);
   // Where we put new limit calculations
   Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl);
   // Ensure the original loop limit is available from the
   // pre-loop Opaque1 node.
   Node *orig_limit = pre_opaq->original_loop_limit();
   assert(orig_limit != NULL && _igvn.type(orig_limit) != Type::TOP, "");
   SWPointer align_to_ref_p(align_to_ref, this);
   assert(align_to_ref_p.valid(), "sanity");
   // Given:
   //     lim0 == original pre loop limit
   //     V == v_align (power of 2)
   //     invar == extra invariant piece of the address expression
   //     e == offset [ +/- invar ]
   //
   // When reassociating expressions involving '%' the basic rules are:
   //     (a - b) % k == 0   =>  a % k == b % k
   // and:
   //     (a + b) % k == 0   =>  a % k == (k - b) % k
   //
   // For stride > 0 && scale > 0,
   //   Derive the new pre-loop limit "lim" such that the two constraints:
   //     (1) lim = lim0 + N           (where N is some positive integer < V)
   //     (2) (e + lim) % V == 0
   //   are true.
   //
   //   Substituting (1) into (2),
   //     (e + lim0 + N) % V == 0
   //   solve for N:
   //     N = (V - (e + lim0)) % V
   //   substitute back into (1), so that new limit
   //     lim = lim0 + (V - (e + lim0)) % V
   //
   // For stride > 0 && scale < 0
   //   Constraints:
   //     lim = lim0 + N
   //     (e - lim) % V == 0
   //   Solving for lim:
   //     (e - lim0 - N) % V == 0
   //     N = (e - lim0) % V
   //     lim = lim0 + (e - lim0) % V
   //
   // For stride < 0 && scale > 0
   //   Constraints:
   //     lim = lim0 - N
   //     (e + lim) % V == 0
   //   Solving for lim:
   //     (e + lim0 - N) % V == 0
   //     N = (e + lim0) % V
   //     lim = lim0 - (e + lim0) % V
   //
   // For stride < 0 && scale < 0
   //   Constraints:
   //     lim = lim0 - N
   //     (e - lim) % V == 0
   //   Solving for lim:
   //     (e - lim0 + N) % V == 0
   //     N = (V - (e - lim0)) % V
   //     lim = lim0 - (V - (e - lim0)) % V
   int vw = vector_width_in_bytes(align_to_ref);
   int stride   = iv_stride();
   int scale    = align_to_ref_p.scale_in_bytes();
   int elt_size = align_to_ref_p.memory_size();
   int v_align  = vw / elt_size;
   assert(v_align > 1, "sanity");
   int offset   = align_to_ref_p.offset_in_bytes() / elt_size;
   Node *offsn  = _igvn.intcon(offset);
   Node *e = offsn;
   if (align_to_ref_p.invar() != NULL) {
     // incorporate any extra invariant piece producing (offset +/- invar) >>> log2(elt)
     Node* log2_elt = _igvn.intcon(exact_log2(elt_size));
     Node* aref     = new (_phase->C) URShiftINode(align_to_ref_p.invar(), log2_elt);
     _igvn.register_new_node_with_optimizer(aref);
     _phase->set_ctrl(aref, pre_ctrl);
     if (align_to_ref_p.negate_invar()) {
       e = new (_phase->C) SubINode(e, aref);
     } else {
       e = new (_phase->C) AddINode(e, aref);
     }
     _igvn.register_new_node_with_optimizer(e);
     _phase->set_ctrl(e, pre_ctrl);
   }
   if (vw > ObjectAlignmentInBytes) {
     // incorporate base e +/- base && Mask >>> log2(elt)
     Node* xbase = new(_phase->C) CastP2XNode(NULL, align_to_ref_p.base());
     _igvn.register_new_node_with_optimizer(xbase);
 #ifdef _LP64
     xbase  = new (_phase->C) ConvL2INode(xbase);
     _igvn.register_new_node_with_optimizer(xbase);
 #endif
     Node* mask = _igvn.intcon(vw-1);
     Node* masked_xbase  = new (_phase->C) AndINode(xbase, mask);
     _igvn.register_new_node_with_optimizer(masked_xbase);
     Node* log2_elt = _igvn.intcon(exact_log2(elt_size));
     Node* bref     = new (_phase->C) URShiftINode(masked_xbase, log2_elt);
     _igvn.register_new_node_with_optimizer(bref);
     _phase->set_ctrl(bref, pre_ctrl);
     e = new (_phase->C) AddINode(e, bref);
     _igvn.register_new_node_with_optimizer(e);
     _phase->set_ctrl(e, pre_ctrl);
   }
   // compute e +/- lim0
   if (scale < 0) {
     e = new (_phase->C) SubINode(e, lim0);
   } else {
     e = new (_phase->C) AddINode(e, lim0);
   }
   _igvn.register_new_node_with_optimizer(e);
   _phase->set_ctrl(e, pre_ctrl);
   if (stride * scale > 0) {
     // compute V - (e +/- lim0)
     Node* va  = _igvn.intcon(v_align);
     e = new (_phase->C) SubINode(va, e);
     _igvn.register_new_node_with_optimizer(e);
     _phase->set_ctrl(e, pre_ctrl);
   }
   // compute N = (exp) % V
   Node* va_msk = _igvn.intcon(v_align - 1);
   Node* N = new (_phase->C) AndINode(e, va_msk);
   _igvn.register_new_node_with_optimizer(N);
   _phase->set_ctrl(N, pre_ctrl);
   //   substitute back into (1), so that new limit
   //     lim = lim0 + N
   Node* lim;
   if (stride < 0) {
     lim = new (_phase->C) SubINode(lim0, N);
   } else {
     lim = new (_phase->C) AddINode(lim0, N);
   }
   _igvn.register_new_node_with_optimizer(lim);
   _phase->set_ctrl(lim, pre_ctrl);
   Node* constrained =
     (stride > 0) ? (Node*) new (_phase->C) MinINode(lim, orig_limit)
                  : (Node*) new (_phase->C) MaxINode(lim, orig_limit);
   _igvn.register_new_node_with_optimizer(constrained);
   _phase->set_ctrl(constrained, pre_ctrl);
   _igvn.hash_delete(pre_opaq);
   pre_opaq->set_req(1, constrained);
 }
 //----------------------------get_pre_loop_end---------------------------
 // Find pre loop end from main loop.  Returns null if none.
 CountedLoopEndNode* SuperWord::get_pre_loop_end(CountedLoopNode* cl) {
   // The loop cannot be optimized if the graph shape at
   // the loop entry is inappropriate.
   if (!PhaseIdealLoop::is_canonical_main_loop_entry(cl)) {
     return NULL;
   }
   Node* p_f = cl->in(LoopNode::EntryControl)->in(0)->in(0);
   if (!p_f->is_IfFalse()) return NULL;
   if (!p_f->in(0)->is_CountedLoopEnd()) return NULL;
   CountedLoopEndNode* pre_end = p_f->in(0)->as_CountedLoopEnd();
   CountedLoopNode* loop_node = pre_end->loopnode();
   if (loop_node == NULL || !loop_node->is_pre_loop()) return NULL;
   return pre_end;
 }
 //------------------------------init---------------------------
 void SuperWord::init() {
   _dg.init();
   _packset.clear();
   _disjoint_ptrs.clear();
   _block.clear();
   _data_entry.clear();
   _mem_slice_head.clear();
   _mem_slice_tail.clear();
   _node_info.clear();
   _align_to_ref = NULL;
   _lpt = NULL;
   _lp = NULL;
   _bb = NULL;
   _iv = NULL;
 }
 //------------------------------print_packset---------------------------
 void SuperWord::print_packset() {
 #ifndef PRODUCT
   tty->print_cr("packset");
   for (int i = 0; i < _packset.length(); i++) {
     tty->print_cr("Pack: %d", i);
     Node_List* p = _packset.at(i);
     print_pack(p);
   }
 #endif
 }
 //------------------------------print_pack---------------------------
 void SuperWord::print_pack(Node_List* p) {
   for (uint i = 0; i < p->size(); i++) {
     print_stmt(p->at(i));
   }
 }
 //------------------------------print_bb---------------------------
 void SuperWord::print_bb() {
 #ifndef PRODUCT
   tty->print_cr("\nBlock");
   for (int i = 0; i < _block.length(); i++) {
     Node* n = _block.at(i);
     tty->print("%d ", i);
     if (n) {
       n->dump();
     }
   }
 #endif
 }
 //------------------------------print_stmt---------------------------
 void SuperWord::print_stmt(Node* s) {
 #ifndef PRODUCT
   tty->print(" align: %d \t", alignment(s));
   s->dump();
 #endif
 }
 //------------------------------blank---------------------------
 char* SuperWord::blank(uint depth) {
   static char blanks[101];
   assert(depth < 101, "too deep");
   for (uint i = 0; i < depth; i++) blanks[i] = ' ';
   blanks[depth] = '\0';
   return blanks;
 }
 //==============================SWPointer===========================
 //----------------------------SWPointer------------------------
 SWPointer::SWPointer(MemNode* mem, SuperWord* slp) :
   _mem(mem), _slp(slp),  _base(NULL),  _adr(NULL),
   _scale(0), _offset(0), _invar(NULL), _negate_invar(false) {
   Node* adr = mem->in(MemNode::Address);
   if (!adr->is_AddP()) {
     assert(!valid(), "too complex");
     return;
   }
   // Match AddP(base, AddP(ptr, k*iv [+ invariant]), constant)
   Node* base = adr->in(AddPNode::Base);
   // The base address should be loop invariant
   if (!invariant(base)) {
     assert(!valid(), "base address is loop variant");
     return;
   }
   //unsafe reference could not be aligned appropriately without runtime checking
   if (base == NULL || base->bottom_type() == Type::TOP) {
     assert(!valid(), "unsafe access");
     return;
   }
   for (int i = 0; i < 3; i++) {
     if (!scaled_iv_plus_offset(adr->in(AddPNode::Offset))) {
       assert(!valid(), "too complex");
       return;
     }
     adr = adr->in(AddPNode::Address);
     if (base == adr || !adr->is_AddP()) {
       break; // stop looking at addp's
     }
   }
   _base = base;
   _adr  = adr;
   assert(valid(), "Usable");
 }
 // Following is used to create a temporary object during
 // the pattern match of an address expression.
 SWPointer::SWPointer(SWPointer* p) :
   _mem(p->_mem), _slp(p->_slp),  _base(NULL),  _adr(NULL),
   _scale(0), _offset(0), _invar(NULL), _negate_invar(false) {}
 //------------------------scaled_iv_plus_offset--------------------
 // Match: k*iv + offset
 // where: k is a constant that maybe zero, and
 //        offset is (k2 [+/- invariant]) where k2 maybe zero and invariant is optional
 bool SWPointer::scaled_iv_plus_offset(Node* n) {
   if (scaled_iv(n)) {
     return true;
   }
   if (offset_plus_k(n)) {
     return true;
   }
   int opc = n->Opcode();
   if (opc == Op_AddI) {
     if (scaled_iv(n->in(1)) && offset_plus_k(n->in(2))) {
       return true;
     }
     if (scaled_iv(n->in(2)) && offset_plus_k(n->in(1))) {
       return true;
     }
   } else if (opc == Op_SubI) {
     if (scaled_iv(n->in(1)) && offset_plus_k(n->in(2), true)) {
       return true;
     }
     if (scaled_iv(n->in(2)) && offset_plus_k(n->in(1))) {
       _scale *= -1;
       return true;
     }
   }
   return false;
 }
 //----------------------------scaled_iv------------------------
 // Match: k*iv where k is a constant that's not zero
 bool SWPointer::scaled_iv(Node* n) {
   if (_scale != 0) {
     return false;  // already found a scale
   }
   if (n == iv()) {
     _scale = 1;
     return true;
   }
   int opc = n->Opcode();
   if (opc == Op_MulI) {
     if (n->in(1) == iv() && n->in(2)->is_Con()) {
       _scale = n->in(2)->get_int();
       return true;
     } else if (n->in(2) == iv() && n->in(1)->is_Con()) {
       _scale = n->in(1)->get_int();
       return true;
     }
   } else if (opc == Op_LShiftI) {
     if (n->in(1) == iv() && n->in(2)->is_Con()) {
       _scale = 1 << n->in(2)->get_int();
       return true;
     }
   } else if (opc == Op_ConvI2L) {
     if (n->in(1)->Opcode() == Op_CastII &&
         n->in(1)->as_CastII()->has_range_check()) {
       // Skip range check dependent CastII nodes
       n = n->in(1);
     }
     if (scaled_iv_plus_offset(n->in(1))) {
       return true;
     }
   } else if (opc == Op_LShiftL) {
     if (!has_iv() && _invar == NULL) {
       // Need to preserve the current _offset value, so
       // create a temporary object for this expression subtree.
       // Hacky, so should re-engineer the address pattern match.
       SWPointer tmp(this);
       if (tmp.scaled_iv_plus_offset(n->in(1))) {
         if (tmp._invar == NULL) {
           int mult = 1 << n->in(2)->get_int();
           _scale   = tmp._scale  * mult;
           _offset += tmp._offset * mult;
           return true;
         }
       }
     }
   }
   return false;
 }
 //----------------------------offset_plus_k------------------------
 // Match: offset is (k [+/- invariant])
 // where k maybe zero and invariant is optional, but not both.
 bool SWPointer::offset_plus_k(Node* n, bool negate) {
   int opc = n->Opcode();
   if (opc == Op_ConI) {
     _offset += negate ? -(n->get_int()) : n->get_int();
     return true;
   } else if (opc == Op_ConL) {
     // Okay if value fits into an int
     const TypeLong* t = n->find_long_type();
     if (t->higher_equal(TypeLong::INT)) {
       jlong loff = n->get_long();
       jint  off  = (jint)loff;
       _offset += negate ? -off : loff;
       return true;
     }
     return false;
   }
   if (_invar != NULL) return false; // already have an invariant
   if (opc == Op_AddI) {
     if (n->in(2)->is_Con() && invariant(n->in(1))) {
       _negate_invar = negate;
       _invar = n->in(1);
       _offset += negate ? -(n->in(2)->get_int()) : n->in(2)->get_int();
       return true;
     } else if (n->in(1)->is_Con() && invariant(n->in(2))) {
       _offset += negate ? -(n->in(1)->get_int()) : n->in(1)->get_int();
       _negate_invar = negate;
       _invar = n->in(2);
       return true;
     }
   }
   if (opc == Op_SubI) {
     if (n->in(2)->is_Con() && invariant(n->in(1))) {
       _negate_invar = negate;
       _invar = n->in(1);
       _offset += !negate ? -(n->in(2)->get_int()) : n->in(2)->get_int();
       return true;
     } else if (n->in(1)->is_Con() && invariant(n->in(2))) {
       _offset += negate ? -(n->in(1)->get_int()) : n->in(1)->get_int();
       _negate_invar = !negate;
       _invar = n->in(2);
       return true;
     }
   }
   if (invariant(n)) {
     _negate_invar = negate;
     _invar = n;
     return true;
   }
   return false;
 }
 //----------------------------print------------------------
 void SWPointer::print() {
 #ifndef PRODUCT
   tty->print("base: %d  adr: %d  scale: %d  offset: %d  invar: %c%d\n",
              _base != NULL ? _base->_idx : 0,
              _adr  != NULL ? _adr->_idx  : 0,
              _scale, _offset,
              _negate_invar?'-':'+',
              _invar != NULL ? _invar->_idx : 0);
 #endif
 }
 // ========================= OrderedPair =====================
 const OrderedPair OrderedPair::initial;
 // ========================= SWNodeInfo =====================
 const SWNodeInfo SWNodeInfo::initial;
 // ============================ DepGraph ===========================
 //------------------------------make_node---------------------------
 // Make a new dependence graph node for an ideal node.
 DepMem* DepGraph::make_node(Node* node) {
   DepMem* m = new (_arena) DepMem(node);
   if (node != NULL) {
     assert(_map.at_grow(node->_idx) == NULL, "one init only");
     _map.at_put_grow(node->_idx, m);
   }
   return m;
 }
 //------------------------------make_edge---------------------------
 // Make a new dependence graph edge from dpred -> dsucc
 DepEdge* DepGraph::make_edge(DepMem* dpred, DepMem* dsucc) {
   DepEdge* e = new (_arena) DepEdge(dpred, dsucc, dsucc->in_head(), dpred->out_head());
   dpred->set_out_head(e);
   dsucc->set_in_head(e);
   return e;
 }
 // ========================== DepMem ========================
 //------------------------------in_cnt---------------------------
 int DepMem::in_cnt() {
   int ct = 0;
   for (DepEdge* e = _in_head; e != NULL; e = e->next_in()) ct++;
   return ct;
 }
 //------------------------------out_cnt---------------------------
 int DepMem::out_cnt() {
   int ct = 0;
   for (DepEdge* e = _out_head; e != NULL; e = e->next_out()) ct++;
   return ct;
 }
 //------------------------------print-----------------------------
 void DepMem::print() {
 #ifndef PRODUCT
   tty->print("  DepNode %d (", _node->_idx);
   for (DepEdge* p = _in_head; p != NULL; p = p->next_in()) {
     Node* pred = p->pred()->node();
     tty->print(" %d", pred != NULL ? pred->_idx : 0);
   }
   tty->print(") [");
   for (DepEdge* s = _out_head; s != NULL; s = s->next_out()) {
     Node* succ = s->succ()->node();
     tty->print(" %d", succ != NULL ? succ->_idx : 0);
   }
   tty->print_cr(" ]");
 #endif
 }
 // =========================== DepEdge =========================
 //------------------------------DepPreds---------------------------
 void DepEdge::print() {
 #ifndef PRODUCT
   tty->print_cr("DepEdge: %d [ %d ]", _pred->node()->_idx, _succ->node()->_idx);
 #endif
 }
 // =========================== DepPreds =========================
 // Iterator over predecessor edges in the dependence graph.
 //------------------------------DepPreds---------------------------
 DepPreds::DepPreds(Node* n, DepGraph& dg) {
   _n = n;
   _done = false;
   if (_n->is_Store() || _n->is_Load()) {
     _next_idx = MemNode::Address;
     _end_idx  = n->req();
     _dep_next = dg.dep(_n)->in_head();
   } else if (_n->is_Mem()) {
     _next_idx = 0;
     _end_idx  = 0;
     _dep_next = dg.dep(_n)->in_head();
   } else {
     _next_idx = 1;
     _end_idx  = _n->req();
     _dep_next = NULL;
   }
   next();
 }
 //------------------------------next---------------------------
 void DepPreds::next() {
   if (_dep_next != NULL) {
     _current  = _dep_next->pred()->node();
     _dep_next = _dep_next->next_in();
   } else if (_next_idx < _end_idx) {
     _current  = _n->in(_next_idx++);
   } else {
     _done = true;
   }
 }
 // =========================== DepSuccs =========================
 // Iterator over successor edges in the dependence graph.
 //------------------------------DepSuccs---------------------------
 DepSuccs::DepSuccs(Node* n, DepGraph& dg) {
   _n = n;
   _done = false;
   if (_n->is_Load()) {
     _next_idx = 0;
     _end_idx  = _n->outcnt();
     _dep_next = dg.dep(_n)->out_head();
   } else if (_n->is_Mem() || _n->is_Phi() && _n->bottom_type() == Type::MEMORY) {
     _next_idx = 0;
     _end_idx  = 0;
     _dep_next = dg.dep(_n)->out_head();
   } else {
     _next_idx = 0;
     _end_idx  = _n->outcnt();
     _dep_next = NULL;
   }
   next();
 }
 //-------------------------------next---------------------------
 void DepSuccs::next() {
   if (_dep_next != NULL) {
     _current  = _dep_next->succ()->node();
     _dep_next = _dep_next->next_out();
   } else if (_next_idx < _end_idx) {
     _current  = _n->raw_out(_next_idx++);
   } else {
     _done = true;
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/superword.cpp@eb7ce841ccec (annotated)

src/share/vm/opto/superword.cpp