1 /*
2 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 #ifndef SHARE_VM_OPTO_SUPERWORD_HPP
25 #define SHARE_VM_OPTO_SUPERWORD_HPP
26
27 #include "opto/connode.hpp"
28 #include "opto/loopnode.hpp"
29 #include "opto/node.hpp"
30 #include "opto/phaseX.hpp"
31 #include "opto/vectornode.hpp"
32 #include "utilities/growableArray.hpp"
33
34 //
35 // S U P E R W O R D T R A N S F O R M
36 //
37 // SuperWords are short, fixed length vectors.
38 //
39 // Algorithm from:
40 //
41 // Exploiting SuperWord Level Parallelism with
42 // Multimedia Instruction Sets
43 // by
44 // Samuel Larsen and Saman Amarasinghe
45 // MIT Laboratory for Computer Science
46 // date
47 // May 2000
48 // published in
49 // ACM SIGPLAN Notices
50 // Proceedings of ACM PLDI '00, Volume 35 Issue 5
51 //
52 // Definition 3.1 A Pack is an n-tuple, <s1, ...,sn>, where
53 // s1,...,sn are independent isomorphic statements in a basic
54 // block.
55 //
56 // Definition 3.2 A PackSet is a set of Packs.
57 //
58 // Definition 3.3 A Pair is a Pack of size two, where the
59 // first statement is considered the left element, and the
60 // second statement is considered the right element.
61
62 class SWPointer;
63 class OrderedPair;
64
65 // ========================= Dependence Graph =====================
66
67 class DepMem;
68
69 //------------------------------DepEdge---------------------------
70 // An edge in the dependence graph. The edges incident to a dependence
71 // node are threaded through _next_in for incoming edges and _next_out
72 // for outgoing edges.
73 class DepEdge : public ResourceObj {
74 protected:
75 DepMem* _pred;
76 DepMem* _succ;
77 DepEdge* _next_in; // list of in edges, null terminated
78 DepEdge* _next_out; // list of out edges, null terminated
79
80 public:
81 DepEdge(DepMem* pred, DepMem* succ, DepEdge* next_in, DepEdge* next_out) :
82 _pred(pred), _succ(succ), _next_in(next_in), _next_out(next_out) {}
83
84 DepEdge* next_in() { return _next_in; }
85 DepEdge* next_out() { return _next_out; }
86 DepMem* pred() { return _pred; }
87 DepMem* succ() { return _succ; }
88
89 void print();
90 };
91
92 //------------------------------DepMem---------------------------
93 // A node in the dependence graph. _in_head starts the threaded list of
94 // incoming edges, and _out_head starts the list of outgoing edges.
95 class DepMem : public ResourceObj {
96 protected:
97 Node* _node; // Corresponding ideal node
98 DepEdge* _in_head; // Head of list of in edges, null terminated
99 DepEdge* _out_head; // Head of list of out edges, null terminated
100
101 public:
102 DepMem(Node* node) : _node(node), _in_head(NULL), _out_head(NULL) {}
103
104 Node* node() { return _node; }
105 DepEdge* in_head() { return _in_head; }
106 DepEdge* out_head() { return _out_head; }
107 void set_in_head(DepEdge* hd) { _in_head = hd; }
108 void set_out_head(DepEdge* hd) { _out_head = hd; }
109
110 int in_cnt(); // Incoming edge count
111 int out_cnt(); // Outgoing edge count
112
113 void print();
114 };
115
116 //------------------------------DepGraph---------------------------
117 class DepGraph VALUE_OBJ_CLASS_SPEC {
118 protected:
119 Arena* _arena;
120 GrowableArray<DepMem*> _map;
121 DepMem* _root;
122 DepMem* _tail;
123
124 public:
125 DepGraph(Arena* a) : _arena(a), _map(a, 8, 0, NULL) {
126 _root = new (_arena) DepMem(NULL);
127 _tail = new (_arena) DepMem(NULL);
128 }
129
130 DepMem* root() { return _root; }
131 DepMem* tail() { return _tail; }
132
133 // Return dependence node corresponding to an ideal node
134 DepMem* dep(Node* node) { return _map.at(node->_idx); }
135
136 // Make a new dependence graph node for an ideal node.
137 DepMem* make_node(Node* node);
138
139 // Make a new dependence graph edge dprec->dsucc
140 DepEdge* make_edge(DepMem* dpred, DepMem* dsucc);
141
142 DepEdge* make_edge(Node* pred, Node* succ) { return make_edge(dep(pred), dep(succ)); }
143 DepEdge* make_edge(DepMem* pred, Node* succ) { return make_edge(pred, dep(succ)); }
144 DepEdge* make_edge(Node* pred, DepMem* succ) { return make_edge(dep(pred), succ); }
145
146 void init() { _map.clear(); } // initialize
147
148 void print(Node* n) { dep(n)->print(); }
149 void print(DepMem* d) { d->print(); }
150 };
151
152 //------------------------------DepPreds---------------------------
153 // Iterator over predecessors in the dependence graph and
154 // non-memory-graph inputs of ideal nodes.
155 class DepPreds : public StackObj {
156 private:
157 Node* _n;
158 int _next_idx, _end_idx;
159 DepEdge* _dep_next;
160 Node* _current;
161 bool _done;
162
163 public:
164 DepPreds(Node* n, DepGraph& dg);
165 Node* current() { return _current; }
166 bool done() { return _done; }
167 void next();
168 };
169
170 //------------------------------DepSuccs---------------------------
171 // Iterator over successors in the dependence graph and
172 // non-memory-graph outputs of ideal nodes.
173 class DepSuccs : public StackObj {
174 private:
175 Node* _n;
176 int _next_idx, _end_idx;
177 DepEdge* _dep_next;
178 Node* _current;
179 bool _done;
180
181 public:
182 DepSuccs(Node* n, DepGraph& dg);
183 Node* current() { return _current; }
184 bool done() { return _done; }
185 void next();
186 };
187
188
189 // ========================= SuperWord =====================
190
191 // -----------------------------SWNodeInfo---------------------------------
192 // Per node info needed by SuperWord
193 class SWNodeInfo VALUE_OBJ_CLASS_SPEC {
194 public:
195 int _alignment; // memory alignment for a node
196 int _depth; // Max expression (DAG) depth from block start
197 const Type* _velt_type; // vector element type
198 Node_List* _my_pack; // pack containing this node
199
200 SWNodeInfo() : _alignment(-1), _depth(0), _velt_type(NULL), _my_pack(NULL) {}
201 static const SWNodeInfo initial;
202 };
203
204
205 // JVMCI: OrderedPair is moved up to deal with compilation issues on Windows
206 //------------------------------OrderedPair---------------------------
207 // Ordered pair of Node*.
208 class OrderedPair VALUE_OBJ_CLASS_SPEC {
209 protected:
210 Node* _p1;
211 Node* _p2;
212 public:
213 OrderedPair() : _p1(NULL), _p2(NULL) {}
214 OrderedPair(Node* p1, Node* p2) {
215 if (p1->_idx < p2->_idx) {
216 _p1 = p1; _p2 = p2;
217 } else {
218 _p1 = p2; _p2 = p1;
219 }
220 }
221
222 bool operator==(const OrderedPair &rhs) {
223 return _p1 == rhs._p1 && _p2 == rhs._p2;
224 }
225 void print() { tty->print(" (%d, %d)", _p1->_idx, _p2->_idx); }
226
227 static const OrderedPair initial;
228 };
229
230 // -----------------------------SuperWord---------------------------------
231 // Transforms scalar operations into packed (superword) operations.
232 class SuperWord : public ResourceObj {
233 private:
234 PhaseIdealLoop* _phase;
235 Arena* _arena;
236 PhaseIterGVN &_igvn;
237
238 enum consts { top_align = -1, bottom_align = -666 };
239
240 GrowableArray<Node_List*> _packset; // Packs for the current block
241
242 GrowableArray<int> _bb_idx; // Map from Node _idx to index within block
243
244 GrowableArray<Node*> _block; // Nodes in current block
245 GrowableArray<Node*> _data_entry; // Nodes with all inputs from outside
246 GrowableArray<Node*> _mem_slice_head; // Memory slice head nodes
247 GrowableArray<Node*> _mem_slice_tail; // Memory slice tail nodes
248
249 GrowableArray<SWNodeInfo> _node_info; // Info needed per node
250
251 MemNode* _align_to_ref; // Memory reference that pre-loop will align to
252
253 GrowableArray<OrderedPair> _disjoint_ptrs; // runtime disambiguated pointer pairs
254
255 DepGraph _dg; // Dependence graph
256
257 // Scratch pads
258 VectorSet _visited; // Visited set
259 VectorSet _post_visited; // Post-visited set
260 Node_Stack _n_idx_list; // List of (node,index) pairs
261 GrowableArray<Node*> _nlist; // List of nodes
262 GrowableArray<Node*> _stk; // Stack of nodes
263
264 public:
265 SuperWord(PhaseIdealLoop* phase);
266
267 void transform_loop(IdealLoopTree* lpt);
268
269 // Accessors for SWPointer
270 PhaseIdealLoop* phase() { return _phase; }
271 IdealLoopTree* lpt() { return _lpt; }
272 PhiNode* iv() { return _iv; }
273
274 private:
275 IdealLoopTree* _lpt; // Current loop tree node
276 LoopNode* _lp; // Current LoopNode
277 Node* _bb; // Current basic block
278 PhiNode* _iv; // Induction var
279
280 // Accessors
281 Arena* arena() { return _arena; }
282
283 Node* bb() { return _bb; }
284 void set_bb(Node* bb) { _bb = bb; }
285
286 void set_lpt(IdealLoopTree* lpt) { _lpt = lpt; }
287
288 LoopNode* lp() { return _lp; }
289 void set_lp(LoopNode* lp) { _lp = lp;
290 _iv = lp->as_CountedLoop()->phi()->as_Phi(); }
291 int iv_stride() { return lp()->as_CountedLoop()->stride_con(); }
292
293 int vector_width(Node* n) {
294 BasicType bt = velt_basic_type(n);
295 return MIN2(ABS(iv_stride()), Matcher::max_vector_size(bt));
296 }
297 int vector_width_in_bytes(Node* n) {
298 BasicType bt = velt_basic_type(n);
299 return vector_width(n)*type2aelembytes(bt);
300 }
301 MemNode* align_to_ref() { return _align_to_ref; }
302 void set_align_to_ref(MemNode* m) { _align_to_ref = m; }
303
304 Node* ctrl(Node* n) const { return _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; }
305
306 // block accessors
307 bool in_bb(Node* n) { return n != NULL && n->outcnt() > 0 && ctrl(n) == _bb; }
308 int bb_idx(Node* n) { assert(in_bb(n), "must be"); return _bb_idx.at(n->_idx); }
309 void set_bb_idx(Node* n, int i) { _bb_idx.at_put_grow(n->_idx, i); }
310
311 // visited set accessors
312 void visited_clear() { _visited.Clear(); }
313 void visited_set(Node* n) { return _visited.set(bb_idx(n)); }
314 int visited_test(Node* n) { return _visited.test(bb_idx(n)); }
315 int visited_test_set(Node* n) { return _visited.test_set(bb_idx(n)); }
316 void post_visited_clear() { _post_visited.Clear(); }
317 void post_visited_set(Node* n) { return _post_visited.set(bb_idx(n)); }
318 int post_visited_test(Node* n) { return _post_visited.test(bb_idx(n)); }
319
320 // Ensure node_info contains element "i"
321 void grow_node_info(int i) { if (i >= _node_info.length()) _node_info.at_put_grow(i, SWNodeInfo::initial); }
322
323 // memory alignment for a node
324 int alignment(Node* n) { return _node_info.adr_at(bb_idx(n))->_alignment; }
325 void set_alignment(Node* n, int a) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_alignment = a; }
326
327 // Max expression (DAG) depth from beginning of the block for each node
328 int depth(Node* n) { return _node_info.adr_at(bb_idx(n))->_depth; }
329 void set_depth(Node* n, int d) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_depth = d; }
330
331 // vector element type
332 const Type* velt_type(Node* n) { return _node_info.adr_at(bb_idx(n))->_velt_type; }
333 BasicType velt_basic_type(Node* n) { return velt_type(n)->array_element_basic_type(); }
334 void set_velt_type(Node* n, const Type* t) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_velt_type = t; }
335 bool same_velt_type(Node* n1, Node* n2);
336
337 // my_pack
338 Node_List* my_pack(Node* n) { return !in_bb(n) ? NULL : _node_info.adr_at(bb_idx(n))->_my_pack; }
339 void set_my_pack(Node* n, Node_List* p) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_my_pack = p; }
340
341 // methods
342
343 // Extract the superword level parallelism
344 void SLP_extract();
345 // Find the adjacent memory references and create pack pairs for them.
346 void find_adjacent_refs();
347 // Find a memory reference to align the loop induction variable to.
348 MemNode* find_align_to_ref(Node_List &memops);
349 // Calculate loop's iv adjustment for this memory ops.
350 int get_iv_adjustment(MemNode* mem);
351 // Can the preloop align the reference to position zero in the vector?
352 bool ref_is_alignable(SWPointer& p);
353 // Construct dependency graph.
354 void dependence_graph();
355 // Return a memory slice (node list) in predecessor order starting at "start"
356 void mem_slice_preds(Node* start, Node* stop, GrowableArray<Node*> &preds);
357 // Can s1 and s2 be in a pack with s1 immediately preceding s2 and s1 aligned at "align"
358 bool stmts_can_pack(Node* s1, Node* s2, int align);
359 // Does s exist in a pack at position pos?
360 bool exists_at(Node* s, uint pos);
361 // Is s1 immediately before s2 in memory?
362 bool are_adjacent_refs(Node* s1, Node* s2);
363 // Are s1 and s2 similar?
364 bool isomorphic(Node* s1, Node* s2);
365 // Is there no data path from s1 to s2 or s2 to s1?
366 bool independent(Node* s1, Node* s2);
367 // Helper for independent
368 bool independent_path(Node* shallow, Node* deep, uint dp=0);
369 void set_alignment(Node* s1, Node* s2, int align);
370 int data_size(Node* s);
371 // Extend packset by following use->def and def->use links from pack members.
372 void extend_packlist();
373 // Extend the packset by visiting operand definitions of nodes in pack p
374 bool follow_use_defs(Node_List* p);
375 // Extend the packset by visiting uses of nodes in pack p
376 bool follow_def_uses(Node_List* p);
377 // Estimate the savings from executing s1 and s2 as a pack
378 int est_savings(Node* s1, Node* s2);
379 int adjacent_profit(Node* s1, Node* s2);
380 int pack_cost(int ct);
381 int unpack_cost(int ct);
382 // Combine packs A and B with A.last == B.first into A.first..,A.last,B.second,..B.last
383 void combine_packs();
384 // Construct the map from nodes to packs.
385 void construct_my_pack_map();
386 // Remove packs that are not implemented or not profitable.
387 void filter_packs();
388 // Adjust the memory graph for the packed operations
389 void schedule();
390 // Remove "current" from its current position in the memory graph and insert
391 // it after the appropriate insert points (lip or uip);
392 void remove_and_insert(MemNode *current, MemNode *prev, MemNode *lip, Node *uip, Unique_Node_List &schd_before);
393 // Within a store pack, schedule stores together by moving out the sandwiched memory ops according
394 // to dependence info; and within a load pack, move loads down to the last executed load.
395 void co_locate_pack(Node_List* p);
396 // Convert packs into vector node operations
397 void output();
398 // Create a vector operand for the nodes in pack p for operand: in(opd_idx)
399 Node* vector_opd(Node_List* p, int opd_idx);
400 // Can code be generated for pack p?
401 bool implemented(Node_List* p);
402 // For pack p, are all operands and all uses (with in the block) vector?
403 bool profitable(Node_List* p);
404 // If a use of pack p is not a vector use, then replace the use with an extract operation.
405 void insert_extracts(Node_List* p);
406 // Is use->in(u_idx) a vector use?
407 bool is_vector_use(Node* use, int u_idx);
408 // Construct reverse postorder list of block members
409 bool construct_bb();
410 // Initialize per node info
411 void initialize_bb();
412 // Insert n into block after pos
413 void bb_insert_after(Node* n, int pos);
414 // Compute max depth for expressions from beginning of block
415 void compute_max_depth();
416 // Compute necessary vector element type for expressions
417 void compute_vector_element_type();
418 // Are s1 and s2 in a pack pair and ordered as s1,s2?
419 bool in_packset(Node* s1, Node* s2);
420 // Is s in pack p?
421 Node_List* in_pack(Node* s, Node_List* p);
422 // Remove the pack at position pos in the packset
423 void remove_pack_at(int pos);
424 // Return the node executed first in pack p.
425 Node* executed_first(Node_List* p);
426 // Return the node executed last in pack p.
427 Node* executed_last(Node_List* p);
428 static LoadNode::ControlDependency control_dependency(Node_List* p);
429 // Alignment within a vector memory reference
430 int memory_alignment(MemNode* s, int iv_adjust);
431 // (Start, end] half-open range defining which operands are vector
432 void vector_opd_range(Node* n, uint* start, uint* end);
433 // Smallest type containing range of values
434 const Type* container_type(Node* n);
435 // Adjust pre-loop limit so that in main loop, a load/store reference
436 // to align_to_ref will be a position zero in the vector.
437 void align_initial_loop_index(MemNode* align_to_ref);
438 // Find pre loop end from main loop. Returns null if none.
439 CountedLoopEndNode* get_pre_loop_end(CountedLoopNode *cl);
440 // Is the use of d1 in u1 at the same operand position as d2 in u2?
441 bool opnd_positions_match(Node* d1, Node* u1, Node* d2, Node* u2);
442 void init();
443
444 // print methods
445 void print_packset();
446 void print_pack(Node_List* p);
447 void print_bb();
448 void print_stmt(Node* s);
449 char* blank(uint depth);
450 };
451
452
453 //------------------------------SWPointer---------------------------
454 // Information about an address for dependence checking and vector alignment
455 class SWPointer VALUE_OBJ_CLASS_SPEC {
456 protected:
457 MemNode* _mem; // My memory reference node
458 SuperWord* _slp; // SuperWord class
459
460 Node* _base; // NULL if unsafe nonheap reference
461 Node* _adr; // address pointer
462 jint _scale; // multiplier for iv (in bytes), 0 if no loop iv
463 jint _offset; // constant offset (in bytes)
464 Node* _invar; // invariant offset (in bytes), NULL if none
465 bool _negate_invar; // if true then use: (0 - _invar)
466
467 PhaseIdealLoop* phase() { return _slp->phase(); }
468 IdealLoopTree* lpt() { return _slp->lpt(); }
469 PhiNode* iv() { return _slp->iv(); } // Induction var
470
471 bool invariant(Node* n) {
472 Node *n_c = phase()->get_ctrl(n);
473 return !lpt()->is_member(phase()->get_loop(n_c));
474 }
475
476 // Match: k*iv + offset
477 bool scaled_iv_plus_offset(Node* n);
478 // Match: k*iv where k is a constant that's not zero
479 bool scaled_iv(Node* n);
480 // Match: offset is (k [+/- invariant])
481 bool offset_plus_k(Node* n, bool negate = false);
482
483 public:
484 enum CMP {
485 Less = 1,
486 Greater = 2,
487 Equal = 4,
488 NotEqual = (Less | Greater),
489 NotComparable = (Less | Greater | Equal)
490 };
491
492 SWPointer(MemNode* mem, SuperWord* slp);
493 // Following is used to create a temporary object during
494 // the pattern match of an address expression.
495 SWPointer(SWPointer* p);
496
497 bool valid() { return _adr != NULL; }
498 bool has_iv() { return _scale != 0; }
499
500 Node* base() { return _base; }
501 Node* adr() { return _adr; }
502 MemNode* mem() { return _mem; }
503 int scale_in_bytes() { return _scale; }
504 Node* invar() { return _invar; }
505 bool negate_invar() { return _negate_invar; }
506 int offset_in_bytes() { return _offset; }
507 int memory_size() { return _mem->memory_size(); }
508
509 // Comparable?
510 int cmp(SWPointer& q) {
511 if (valid() && q.valid() &&
512 (_adr == q._adr || _base == _adr && q._base == q._adr) &&
513 _scale == q._scale &&
514 _invar == q._invar &&
515 _negate_invar == q._negate_invar) {
516 bool overlap = q._offset < _offset + memory_size() &&
517 _offset < q._offset + q.memory_size();
518 return overlap ? Equal : (_offset < q._offset ? Less : Greater);
519 } else {
520 return NotComparable;
521 }
522 }
523
524 bool not_equal(SWPointer& q) { return not_equal(cmp(q)); }
525 bool equal(SWPointer& q) { return equal(cmp(q)); }
526 bool comparable(SWPointer& q) { return comparable(cmp(q)); }
527 static bool not_equal(int cmp) { return cmp <= NotEqual; }
528 static bool equal(int cmp) { return cmp == Equal; }
529 static bool comparable(int cmp) { return cmp < NotComparable; }
530
531 void print();
532 };
533
534 #endif // SHARE_VM_OPTO_SUPERWORD_HPP