--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/opto/superword.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,2025 @@
+/*
+ * Copyright 2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_superword.cpp.incl"
+
+//
+// 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(lpt->_head->is_CountedLoop(), "must be");
+ CountedLoopNode *cl = lpt->_head->as_CountedLoop();
+
+ 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;
+
+ // 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;
+
+ // Do vectors exist on this architecture?
+ if (vector_width_in_bytes() == 0) 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
+
+ construct_bb();
+
+ 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() && in_bb(n)) {
+ int align = memory_alignment(n->as_Mem(), 0);
+ if (align != bottom_align) {
+ memops.push(n);
+ }
+ }
+ }
+ if (memops.size() == 0) return;
+
+ // Find a memory reference to align to. The pre-loop trip count
+ // is modified to align this reference to a vector-aligned address
+ find_align_to_ref(memops);
+ if (align_to_ref() == NULL) return;
+
+ SWPointer align_to_ref_p(align_to_ref(), this);
+ int offset = align_to_ref_p.offset_in_bytes();
+ int scale = align_to_ref_p.scale_in_bytes();
+ int vw = vector_width_in_bytes();
+ int stride_sign = (scale * iv_stride()) > 0 ? 1 : -1;
+ int iv_adjustment = (stride_sign * vw - (offset % vw)) % vw;
+
+#ifndef PRODUCT
+ if (TraceSuperWord)
+ tty->print_cr("\noffset = %d iv_adjustment = %d elt_align = %d",
+ offset, iv_adjustment, align_to_ref_p.memory_size());
+#endif
+
+ // Set alignment relative to "align_to_ref"
+ for (int i = memops.size() - 1; i >= 0; i--) {
+ MemNode* s = memops.at(i)->as_Mem();
+ SWPointer p2(s, this);
+ if (p2.comparable(align_to_ref_p)) {
+ int align = memory_alignment(s, iv_adjustment);
+ set_alignment(s, align);
+ } else {
+ memops.remove(i);
+ }
+ }
+
+ // Create initial pack pairs of memory operations
+ for (uint i = 0; i < memops.size(); i++) {
+ Node* s1 = memops.at(i);
+ for (uint j = 0; j < memops.size(); j++) {
+ Node* s2 = memops.at(j);
+ if (s1 != s2 && are_adjacent_refs(s1, s2)) {
+ int align = alignment(s1);
+ if (stmts_can_pack(s1, s2, align)) {
+ Node_List* pair = new Node_List();
+ pair->push(s1);
+ pair->push(s2);
+ _packset.append(pair);
+ }
+ }
+ }
+ }
+
+#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.
+void 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
+ int max_ct = 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()) {
+ SWPointer p(s, this);
+ if (cmp_ct.at(j) > max_ct ||
+ cmp_ct.at(j) == max_ct && (data_size(s) < min_size ||
+ data_size(s) == min_size &&
+ p.offset_in_bytes() < min_iv_offset)) {
+ max_ct = cmp_ct.at(j);
+ 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()) {
+ SWPointer p(s, this);
+ if (cmp_ct.at(j) > max_ct ||
+ cmp_ct.at(j) == max_ct && (data_size(s) < min_size ||
+ data_size(s) == min_size &&
+ p.offset_in_bytes() < min_iv_offset)) {
+ max_ct = cmp_ct.at(j);
+ max_idx = j;
+ min_size = data_size(s);
+ min_iv_offset = p.offset_in_bytes();
+ }
+ }
+ }
+ }
+
+ if (max_ct > 0)
+ set_align_to_ref(memops.at(max_idx)->as_Mem());
+
+#ifndef PRODUCT
+ 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
+}
+
+//------------------------------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->stride_is_con(), "pre loop stride is constant");
+ int preloop_stride = pre_end->stride_con();
+
+ int span = preloop_stride * p.scale_in_bytes();
+
+ // Stride one accesses are alignable.
+ if (ABS(span) == p.memory_size())
+ return true;
+
+ // If initial offset from start of object is computable,
+ // compute alignment within the vector.
+ int vw = vector_width_in_bytes();
+ if (vw % span == 0) {
+ 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() + p.offset_in_bytes();
+ assert(init_offset >= 0, "positive offset from object start");
+
+ if (span > 0) {
+ return (vw - (init_offset % vw)) % span == 0;
+ } else {
+ assert(span < 0, "nonzero stride * scale");
+ return (init_offset % vw) % -span == 0;
+ }
+ }
+ }
+ return false;
+}
+
+//---------------------------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(4) == 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;
+ n = n->in(MemNode::Memory);
+ }
+}
+
+//------------------------------stmts_can_pack---------------------------
+// Can s1 and s2 be in a pack with s1 immediately preceeding s2 and
+// s1 aligned at "align"
+bool SuperWord::stmts_can_pack(Node* s1, Node* s2, int align) {
+ 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;
+ // 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 (velt_type(s1) != velt_type(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);
+ set_alignment(s2, align + data_size(s1));
+}
+
+//------------------------------data_size---------------------------
+int SuperWord::data_size(Node* s) {
+ const Type* t = velt_type(s);
+ BasicType bt = t->array_element_basic_type();
+ int bsize = type2aelembytes[bt];
+ 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) {
+ 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_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) {
+ 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 = 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 += adjacent_profit(x1, x2);
+ } else if (!in_packset(x1, x2)) {
+ save -= pack_cost(2);
+ } else {
+ save += unpack_cost(2);
+ }
+ }
+ }
+
+ // uses of result
+ uint ct = 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 += adjacent_profit(s1_use, s2_use);
+ }
+ }
+ }
+ }
+ }
+ }
+
+ if (ct < s1->outcnt()) save += unpack_cost(1);
+ if (ct < s2->outcnt()) save += unpack_cost(1);
+
+ return save;
+}
+
+//------------------------------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;
+ do {
+ 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 (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;
+ }
+ }
+ }
+ } while (changed);
+
+ 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);
+ int vopc = VectorNode::opcode(p0->Opcode(), p->size(), velt_type(p0));
+ return vopc > 0 && Matcher::has_match_rule(vopc);
+}
+
+//------------------------------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;
+ vector_opd_range(p0, &start, &end);
+
+ // Return false if some input is not vector and inside block
+ for (uint i = start; i < end; i++) {
+ if (!is_vector_use(p0, i)) {
+ // For now, return false if not scalar promotion case (inputs are the same.)
+ // Later, implement PackNode and allow differring, non-vector inputs
+ // (maybe just the ones from outside the block.)
+ Node* p0_def = p0->in(i);
+ for (uint j = 1; j < p->size(); j++) {
+ Node* use = p->at(j);
+ Node* def = use->in(i);
+ if (p0_def != def)
+ 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));
+ }
+}
+
+//------------------------------co_locate_pack---------------------------
+// Within a pack, move stores down to the last executed store,
+// and move loads up to the first executed load.
+void SuperWord::co_locate_pack(Node_List* pk) {
+ if (pk->at(0)->is_Store()) {
+ // Push Stores down towards last executed pack member
+ MemNode* first = executed_first(pk)->as_Mem();
+ MemNode* last = executed_last(pk)->as_Mem();
+ MemNode* insert_pt = last;
+ MemNode* current = last->in(MemNode::Memory)->as_Mem();
+ while (true) {
+ assert(in_bb(current), "stay in block");
+ Node* my_mem = current->in(MemNode::Memory);
+ if (in_pack(current, pk)) {
+ // Forward users of my memory state to my input memory state
+ _igvn.hash_delete(current);
+ _igvn.hash_delete(my_mem);
+ 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");
+ _igvn.hash_delete(use);
+ use->set_req(MemNode::Memory, my_mem);
+ _igvn._worklist.push(use);
+ --i; // deleted this edge; rescan position
+ }
+ }
+ // put current immediately before insert_pt
+ current->set_req(MemNode::Memory, insert_pt->in(MemNode::Memory));
+ _igvn.hash_delete(insert_pt);
+ insert_pt->set_req(MemNode::Memory, current);
+ _igvn._worklist.push(insert_pt);
+ _igvn._worklist.push(current);
+ insert_pt = current;
+ }
+ if (current == first) break;
+ current = my_mem->as_Mem();
+ }
+ } else if (pk->at(0)->is_Load()) {
+ // Pull Loads up towards first executed pack member
+ LoadNode* first = executed_first(pk)->as_Load();
+ Node* first_mem = first->in(MemNode::Memory);
+ _igvn.hash_delete(first_mem);
+ // Give each load same memory state as first
+ for (uint i = 0; i < pk->size(); i++) {
+ LoadNode* ld = pk->at(i)->as_Load();
+ _igvn.hash_delete(ld);
+ ld->set_req(MemNode::Memory, first_mem);
+ _igvn._worklist.push(ld);
+ }
+ }
+}
+
+//------------------------------output---------------------------
+// Convert packs into vector node operations
+void SuperWord::output() {
+ if (_packset.length() == 0) return;
+
+ // 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));
+ }
+
+ 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();
+ Node* vn = NULL;
+ Node* low_adr = p->at(0);
+ Node* first = executed_first(p);
+ if (n->is_Load()) {
+ int opc = n->Opcode();
+ 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 = VectorLoadNode::make(_phase->C, opc, ctl, mem, adr, atyp, vlen);
+
+ } else if (n->is_Store()) {
+ // Promote value to be stored to vector
+ VectorNode* val = vector_opd(p, MemNode::ValueIn);
+
+ int opc = n->Opcode();
+ 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 = VectorStoreNode::make(_phase->C, opc, ctl, mem, adr, atyp, val, vlen);
+
+ } else if (n->req() == 3) {
+ // Promote operands to vector
+ Node* in1 = vector_opd(p, 1);
+ Node* in2 = vector_opd(p, 2);
+ vn = VectorNode::make(_phase->C, n->Opcode(), in1, in2, vlen, velt_type(n));
+
+ } else {
+ ShouldNotReachHere();
+ }
+
+ _phase->_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.hash_delete(pm);
+ _igvn.subsume_node(pm, vn);
+ }
+ _igvn._worklist.push(vn);
+ }
+ }
+}
+
+//------------------------------vector_opd---------------------------
+// Create a vector operand for the nodes in pack p for operand: in(opd_idx)
+VectorNode* SuperWord::vector_opd(Node_List* p, int opd_idx) {
+ Node* p0 = p->at(0);
+ uint vlen = p->size();
+ Node* opd = p0->in(opd_idx);
+
+ bool same_opd = true;
+ for (uint i = 1; i < vlen; i++) {
+ Node* pi = p->at(i);
+ Node* in = pi->in(opd_idx);
+ if (opd != in) {
+ same_opd = false;
+ break;
+ }
+ }
+
+ if (same_opd) {
+ if (opd->is_Vector()) {
+ return (VectorNode*)opd; // input is matching vector
+ }
+ // Convert scalar input to vector. Use p0's type because it's container
+ // maybe smaller than the operand's container.
+ const Type* opd_t = velt_type(!in_bb(opd) ? p0 : opd);
+ const Type* p0_t = velt_type(p0);
+ if (p0_t->higher_equal(opd_t)) opd_t = p0_t;
+ VectorNode* vn = VectorNode::scalar2vector(_phase->C, opd, vlen, opd_t);
+
+ _phase->_igvn.register_new_node_with_optimizer(vn);
+ _phase->set_ctrl(vn, _phase->get_ctrl(opd));
+ return vn;
+ }
+
+ // Insert pack operation
+ const Type* opd_t = velt_type(!in_bb(opd) ? p0 : opd);
+ PackNode* pk = PackNode::make(_phase->C, opd, opd_t);
+
+ 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_t == velt_type(!in_bb(in) ? pi : in), "all same type");
+ pk->add_opd(in);
+ }
+ _phase->_igvn.register_new_node_with_optimizer(pk);
+ _phase->set_ctrl(pk, _phase->get_ctrl(opd));
+ 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);
+ _igvn.hash_delete(use);
+ int def_pos = alignment(def) / data_size(def);
+ const Type* def_t = velt_type(def);
+
+ Node* ex = ExtractNode::make(_phase->C, def, def_pos, def_t);
+ _phase->_igvn.register_new_node_with_optimizer(ex);
+ _phase->set_ctrl(ex, _phase->get_ctrl(def));
+ use->set_req(idx, ex);
+ _igvn._worklist.push(def);
+ _igvn._worklist.push(use);
+
+ bb_insert_after(ex, bb_idx(def));
+ set_velt_type(ex, def_t);
+ }
+}
+
+//------------------------------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
+void 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)) {
+ 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);
+ _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");
+}
+
+//------------------------------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);
+ const Type* t = n->is_Mem() ? Type::get_const_basic_type(n->as_Mem()->memory_type())
+ : _igvn.type(n);
+ const Type* vt = container_type(t);
+ set_velt_type(n, vt);
+ }
+
+ // Propagate 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
+ if (n->bottom_type()->isa_int()) {
+ uint start, end;
+ vector_opd_range(n, &start, &end);
+ const Type* vt = velt_type(n);
+
+ for (uint j = start; j < end; j++) {
+ Node* in = n->in(j);
+ // Don't propagate through a type conversion
+ if (n->bottom_type() != in->bottom_type())
+ continue;
+ switch(in->Opcode()) {
+ case Op_AddI: case Op_AddL:
+ case Op_SubI: case Op_SubL:
+ case Op_MulI: case Op_MulL:
+ case Op_AndI: case Op_AndL:
+ case Op_OrI: case Op_OrL:
+ case Op_XorI: case Op_XorL:
+ case Op_LShiftI: case Op_LShiftL:
+ case Op_CMoveI: case Op_CMoveL:
+ if (in_bb(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) || velt_type(use) != vt) {
+ same_type = false;
+ break;
+ }
+ }
+ if (same_type) {
+ 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_in_bytes) {
+ SWPointer p(s, this);
+ if (!p.valid()) {
+ return bottom_align;
+ }
+ int offset = p.offset_in_bytes();
+ offset += iv_adjust_in_bytes;
+ int off_rem = offset % vector_width_in_bytes();
+ int off_mod = off_rem >= 0 ? off_rem : off_rem + vector_width_in_bytes();
+ return off_mod;
+}
+
+//---------------------------container_type---------------------------
+// Smallest type containing range of values
+const Type* SuperWord::container_type(const Type* t) {
+ if (t->isa_aryptr()) {
+ t = t->is_aryptr()->elem();
+ }
+ if (t->basic_type() == T_INT) {
+ if (t->higher_equal(TypeInt::BOOL)) return TypeInt::BOOL;
+ if (t->higher_equal(TypeInt::BYTE)) return TypeInt::BYTE;
+ if (t->higher_equal(TypeInt::CHAR)) return TypeInt::CHAR;
+ if (t->higher_equal(TypeInt::SHORT)) return TypeInt::SHORT;
+ return TypeInt::INT;
+ }
+ return t;
+}
+
+//-------------------------vector_opd_range-----------------------
+// (Start, end] half-open range defining which operands are vector
+void SuperWord::vector_opd_range(Node* n, uint* start, uint* end) {
+ switch (n->Opcode()) {
+ case Op_LoadB: case Op_LoadC:
+ case Op_LoadI: case Op_LoadL:
+ case Op_LoadF: case Op_LoadD:
+ case Op_LoadP:
+ *start = 0;
+ *end = 0;
+ return;
+ case Op_StoreB: case Op_StoreC:
+ case Op_StoreI: case Op_StoreL:
+ case Op_StoreF: case Op_StoreD:
+ case Op_StoreP:
+ *start = MemNode::ValueIn;
+ *end = *start + 1;
+ return;
+ case Op_LShiftI: case Op_LShiftL:
+ *start = 1;
+ *end = 2;
+ return;
+ case Op_CMoveI: case Op_CMoveL: case Op_CMoveF: case Op_CMoveD:
+ *start = 2;
+ *end = n->req();
+ return;
+ }
+ *start = 1;
+ *end = n->req(); // default is all operands
+}
+
+//------------------------------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;
+}
+
+//----------------------------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, "");
+ Node *pre_opaq1 = pre_end->limit();
+ assert(pre_opaq1->Opcode() == Op_Opaque1, "");
+ Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1;
+ Node *pre_limit = 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);
+
+ // Let l0 == original pre_limit, l == new pre_limit, V == v_align
+ //
+ // For stride > 0
+ // Need l such that l > l0 && (l+k)%V == 0
+ // Find n such that l = (l0 + n)
+ // (l0 + n + k) % V == 0
+ // n = [V - (l0 + k)%V]%V
+ // new limit = l0 + [V - (l0 + k)%V]%V
+ // For stride < 0
+ // Need l such that l < l0 && (l+k)%V == 0
+ // Find n such that l = (l0 - n)
+ // (l0 - n + k) % V == 0
+ // n = (l0 + k)%V
+ // new limit = l0 - (l0 + k)%V
+
+ int elt_size = align_to_ref_p.memory_size();
+ int v_align = vector_width_in_bytes() / elt_size;
+ int k = align_to_ref_p.offset_in_bytes() / elt_size;
+
+ Node *kn = _igvn.intcon(k);
+ Node *limk = new (_phase->C, 3) AddINode(pre_limit, kn);
+ _phase->_igvn.register_new_node_with_optimizer(limk);
+ _phase->set_ctrl(limk, pre_ctrl);
+ if (align_to_ref_p.invar() != NULL) {
+ Node* log2_elt = _igvn.intcon(exact_log2(elt_size));
+ Node* aref = new (_phase->C, 3) URShiftINode(align_to_ref_p.invar(), log2_elt);
+ _phase->_igvn.register_new_node_with_optimizer(aref);
+ _phase->set_ctrl(aref, pre_ctrl);
+ if (!align_to_ref_p.negate_invar()) {
+ limk = new (_phase->C, 3) AddINode(limk, aref);
+ } else {
+ limk = new (_phase->C, 3) SubINode(limk, aref);
+ }
+ _phase->_igvn.register_new_node_with_optimizer(limk);
+ _phase->set_ctrl(limk, pre_ctrl);
+ }
+ Node* va_msk = _igvn.intcon(v_align - 1);
+ Node* n = new (_phase->C, 3) AndINode(limk, va_msk);
+ _phase->_igvn.register_new_node_with_optimizer(n);
+ _phase->set_ctrl(n, pre_ctrl);
+ Node* newlim;
+ if (iv_stride() > 0) {
+ Node* va = _igvn.intcon(v_align);
+ Node* adj = new (_phase->C, 3) SubINode(va, n);
+ _phase->_igvn.register_new_node_with_optimizer(adj);
+ _phase->set_ctrl(adj, pre_ctrl);
+ Node* adj2 = new (_phase->C, 3) AndINode(adj, va_msk);
+ _phase->_igvn.register_new_node_with_optimizer(adj2);
+ _phase->set_ctrl(adj2, pre_ctrl);
+ newlim = new (_phase->C, 3) AddINode(pre_limit, adj2);
+ } else {
+ newlim = new (_phase->C, 3) SubINode(pre_limit, n);
+ }
+ _phase->_igvn.register_new_node_with_optimizer(newlim);
+ _phase->set_ctrl(newlim, pre_ctrl);
+ Node* constrained =
+ (iv_stride() > 0) ? (Node*) new (_phase->C,3) MinINode(newlim, orig_limit)
+ : (Node*) new (_phase->C,3) MaxINode(newlim, orig_limit);
+ _phase->_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) {
+ Node *ctrl = cl->in(LoopNode::EntryControl);
+ if (!ctrl->is_IfTrue() && !ctrl->is_IfFalse()) return NULL;
+ Node *iffm = ctrl->in(0);
+ if (!iffm->is_If()) return NULL;
+ Node *p_f = iffm->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();
+ if (!pre_end->loopnode()->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);
+ 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 (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;
+ }
+}