1 /*
2 * Copyright (c) 1999, 2023, 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
25 #include "precompiled.hpp"
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "opto/addnode.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/connode.hpp"
34 #include "opto/castnode.hpp"
35 #include "opto/divnode.hpp"
36 #include "opto/inlinetypenode.hpp"
37 #include "opto/loopnode.hpp"
38 #include "opto/matcher.hpp"
39 #include "opto/mulnode.hpp"
40 #include "opto/movenode.hpp"
41 #include "opto/opaquenode.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/subnode.hpp"
44 #include "opto/subtypenode.hpp"
45 #include "opto/superword.hpp"
46 #include "opto/vectornode.hpp"
47 #include "utilities/macros.hpp"
48
49 //=============================================================================
50 //------------------------------split_thru_phi---------------------------------
51 // Split Node 'n' through merge point if there is enough win.
52 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) {
53 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
54 // ConvI2L may have type information on it which is unsafe to push up
55 // so disable this for now
56 return nullptr;
57 }
58
59 // Splitting range check CastIIs through a loop induction Phi can
60 // cause new Phis to be created that are left unrelated to the loop
61 // induction Phi and prevent optimizations (vectorization)
62 if (n->Opcode() == Op_CastII && region->is_CountedLoop() &&
63 n->in(1) == region->as_CountedLoop()->phi()) {
64 return nullptr;
65 }
66
67 // Inline types should not be split through Phis because they cannot be merged
68 // through Phi nodes but each value input needs to be merged individually.
69 if (n->is_InlineType()) {
70 return nullptr;
71 }
72
73 if (cannot_split_division(n, region)) {
74 return nullptr;
75 }
76
77 int wins = 0;
78 assert(!n->is_CFG(), "");
79 assert(region->is_Region(), "");
80
81 const Type* type = n->bottom_type();
82 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr();
83 Node* phi;
84 if (t_oop != nullptr && t_oop->is_known_instance_field()) {
85 int iid = t_oop->instance_id();
86 int index = C->get_alias_index(t_oop);
87 int offset = t_oop->offset();
88 phi = new PhiNode(region, type, nullptr, iid, index, offset);
89 } else {
90 phi = PhiNode::make_blank(region, n);
91 }
92 uint old_unique = C->unique();
93 for (uint i = 1; i < region->req(); i++) {
94 Node* x;
95 Node* the_clone = nullptr;
96 if (region->in(i) == C->top()) {
97 x = C->top(); // Dead path? Use a dead data op
98 } else {
99 x = n->clone(); // Else clone up the data op
100 the_clone = x; // Remember for possible deletion.
101 // Alter data node to use pre-phi inputs
102 if (n->in(0) == region)
103 x->set_req( 0, region->in(i) );
104 for (uint j = 1; j < n->req(); j++) {
105 Node* in = n->in(j);
106 if (in->is_Phi() && in->in(0) == region)
107 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
108 }
109 }
110 // Check for a 'win' on some paths
111 const Type* t = x->Value(&_igvn);
112
113 bool singleton = t->singleton();
114
115 // A TOP singleton indicates that there are no possible values incoming
116 // along a particular edge. In most cases, this is OK, and the Phi will
117 // be eliminated later in an Ideal call. However, we can't allow this to
118 // happen if the singleton occurs on loop entry, as the elimination of
119 // the PhiNode may cause the resulting node to migrate back to a previous
120 // loop iteration.
121 if (singleton && t == Type::TOP) {
122 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
123 // irreducible loop may not be indicated by an affirmative is_Loop());
124 // therefore, the only top we can split thru a phi is on a backedge of
125 // a loop.
126 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
127 }
128
129 if (singleton) {
130 wins++;
131 x = ((PhaseGVN&)_igvn).makecon(t);
132 } else {
133 // We now call Identity to try to simplify the cloned node.
134 // Note that some Identity methods call phase->type(this).
135 // Make sure that the type array is big enough for
136 // our new node, even though we may throw the node away.
137 // (Note: This tweaking with igvn only works because x is a new node.)
138 _igvn.set_type(x, t);
139 // If x is a TypeNode, capture any more-precise type permanently into Node
140 // otherwise it will be not updated during igvn->transform since
141 // igvn->type(x) is set to x->Value() already.
142 x->raise_bottom_type(t);
143 Node* y = x->Identity(&_igvn);
144 if (y != x) {
145 wins++;
146 x = y;
147 } else {
148 y = _igvn.hash_find(x);
149 if (y == nullptr) {
150 y = similar_subtype_check(x, region->in(i));
151 }
152 if (y) {
153 wins++;
154 x = y;
155 } else {
156 // Else x is a new node we are keeping
157 // We do not need register_new_node_with_optimizer
158 // because set_type has already been called.
159 _igvn._worklist.push(x);
160 }
161 }
162 }
163
164 phi->set_req( i, x );
165
166 if (the_clone == nullptr) {
167 continue;
168 }
169
170 if (the_clone != x) {
171 _igvn.remove_dead_node(the_clone);
172 } else if (region->is_Loop() && i == LoopNode::LoopBackControl &&
173 n->is_Load() && can_move_to_inner_loop(n, region->as_Loop(), x)) {
174 // it is not a win if 'x' moved from an outer to an inner loop
175 // this edge case can only happen for Load nodes
176 wins = 0;
177 break;
178 }
179 }
180 // Too few wins?
181 if (wins <= policy) {
182 _igvn.remove_dead_node(phi);
183 return nullptr;
184 }
185
186 // Record Phi
187 register_new_node( phi, region );
188
189 for (uint i2 = 1; i2 < phi->req(); i2++) {
190 Node *x = phi->in(i2);
191 // If we commoned up the cloned 'x' with another existing Node,
192 // the existing Node picks up a new use. We need to make the
193 // existing Node occur higher up so it dominates its uses.
194 Node *old_ctrl;
195 IdealLoopTree *old_loop;
196
197 if (x->is_Con()) {
198 // Constant's control is always root.
199 set_ctrl(x, C->root());
200 continue;
201 }
202 // The occasional new node
203 if (x->_idx >= old_unique) { // Found a new, unplaced node?
204 old_ctrl = nullptr;
205 old_loop = nullptr; // Not in any prior loop
206 } else {
207 old_ctrl = get_ctrl(x);
208 old_loop = get_loop(old_ctrl); // Get prior loop
209 }
210 // New late point must dominate new use
211 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
212 if (new_ctrl == old_ctrl) // Nothing is changed
213 continue;
214
215 IdealLoopTree *new_loop = get_loop(new_ctrl);
216
217 // Don't move x into a loop if its uses are
218 // outside of loop. Otherwise x will be cloned
219 // for each use outside of this loop.
220 IdealLoopTree *use_loop = get_loop(region);
221 if (!new_loop->is_member(use_loop) &&
222 (old_loop == nullptr || !new_loop->is_member(old_loop))) {
223 // Take early control, later control will be recalculated
224 // during next iteration of loop optimizations.
225 new_ctrl = get_early_ctrl(x);
226 new_loop = get_loop(new_ctrl);
227 }
228 // Set new location
229 set_ctrl(x, new_ctrl);
230 // If changing loop bodies, see if we need to collect into new body
231 if (old_loop != new_loop) {
232 if (old_loop && !old_loop->_child)
233 old_loop->_body.yank(x);
234 if (!new_loop->_child)
235 new_loop->_body.push(x); // Collect body info
236 }
237 }
238
239 return phi;
240 }
241
242 // Test whether node 'x' can move into an inner loop relative to node 'n'.
243 // Note: The test is not exact. Returns true if 'x' COULD end up in an inner loop,
244 // BUT it can also return true and 'x' is in the outer loop
245 bool PhaseIdealLoop::can_move_to_inner_loop(Node* n, LoopNode* n_loop, Node* x) {
246 IdealLoopTree* n_loop_tree = get_loop(n_loop);
247 IdealLoopTree* x_loop_tree = get_loop(get_early_ctrl(x));
248 // x_loop_tree should be outer or same loop as n_loop_tree
249 return !x_loop_tree->is_member(n_loop_tree);
250 }
251
252 // Subtype checks that carry profile data don't common so look for a replacement by following edges
253 Node* PhaseIdealLoop::similar_subtype_check(const Node* x, Node* r_in) {
254 if (x->is_SubTypeCheck()) {
255 Node* in1 = x->in(1);
256 for (DUIterator_Fast imax, i = in1->fast_outs(imax); i < imax; i++) {
257 Node* u = in1->fast_out(i);
258 if (u != x && u->is_SubTypeCheck() && u->in(1) == x->in(1) && u->in(2) == x->in(2)) {
259 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) {
260 Node* bol = u->fast_out(j);
261 for (DUIterator_Fast kmax, k = bol->fast_outs(kmax); k < kmax; k++) {
262 Node* iff = bol->fast_out(k);
263 // Only dominating subtype checks are interesting: otherwise we risk replacing a subtype check by another with
264 // unrelated profile
265 if (iff->is_If() && is_dominator(iff, r_in)) {
266 return u;
267 }
268 }
269 }
270 }
271 }
272 }
273 return nullptr;
274 }
275
276 // Return true if 'n' is a Div or Mod node (without zero check If node which was removed earlier) with a loop phi divisor
277 // of a trip-counted (integer or long) loop with a backedge input that could be zero (include zero in its type range). In
278 // this case, we cannot split the division to the backedge as it could freely float above the loop exit check resulting in
279 // a division by zero. This situation is possible because the type of an increment node of an iv phi (trip-counter) could
280 // include zero while the iv phi does not (see PhiNode::Value() for trip-counted loops where we improve types of iv phis).
281 // We also need to check other loop phis as they could have been created in the same split-if pass when applying
282 // PhaseIdealLoop::split_thru_phi() to split nodes through an iv phi.
283 bool PhaseIdealLoop::cannot_split_division(const Node* n, const Node* region) const {
284 const Type* zero;
285 switch (n->Opcode()) {
286 case Op_DivI:
287 case Op_ModI:
288 zero = TypeInt::ZERO;
289 break;
290 case Op_DivL:
291 case Op_ModL:
292 zero = TypeLong::ZERO;
293 break;
294 default:
295 return false;
296 }
297
298 if (n->in(0) != nullptr) {
299 // Cannot split through phi if Div or Mod node has a control dependency to a zero check.
300 return true;
301 }
302
303 Node* divisor = n->in(2);
304 return is_divisor_counted_loop_phi(divisor, region) &&
305 loop_phi_backedge_type_contains_zero(divisor, zero);
306 }
307
308 bool PhaseIdealLoop::is_divisor_counted_loop_phi(const Node* divisor, const Node* loop) {
309 return loop->is_BaseCountedLoop() && divisor->is_Phi() && divisor->in(0) == loop;
310 }
311
312 bool PhaseIdealLoop::loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const {
313 return _igvn.type(phi_divisor->in(LoopNode::LoopBackControl))->filter_speculative(zero) != Type::TOP;
314 }
315
316 //------------------------------dominated_by------------------------------------
317 // Replace the dominated test with an obvious true or false. Place it on the
318 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
319 // live path up to the dominating control.
320 void PhaseIdealLoop::dominated_by(IfProjNode* prevdom, IfNode* iff, bool flip, bool pin_array_access_nodes) {
321 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
322
323 // prevdom is the dominating projection of the dominating test.
324 assert(iff->Opcode() == Op_If ||
325 iff->Opcode() == Op_CountedLoopEnd ||
326 iff->Opcode() == Op_LongCountedLoopEnd ||
327 iff->Opcode() == Op_RangeCheck ||
328 iff->Opcode() == Op_ParsePredicate,
329 "Check this code when new subtype is added");
330
331 int pop = prevdom->Opcode();
332 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
333 if (flip) {
334 if (pop == Op_IfTrue)
335 pop = Op_IfFalse;
336 else
337 pop = Op_IfTrue;
338 }
339 // 'con' is set to true or false to kill the dominated test.
340 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
341 set_ctrl(con, C->root()); // Constant gets a new use
342 // Hack the dominated test
343 _igvn.replace_input_of(iff, 1, con);
344
345 // If I don't have a reachable TRUE and FALSE path following the IfNode then
346 // I can assume this path reaches an infinite loop. In this case it's not
347 // important to optimize the data Nodes - either the whole compilation will
348 // be tossed or this path (and all data Nodes) will go dead.
349 if (iff->outcnt() != 2) return;
350
351 // Make control-dependent data Nodes on the live path (path that will remain
352 // once the dominated IF is removed) become control-dependent on the
353 // dominating projection.
354 Node* dp = iff->proj_out_or_null(pop == Op_IfTrue);
355
356 if (dp == nullptr)
357 return;
358
359 IdealLoopTree* old_loop = get_loop(dp);
360
361 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
362 Node* cd = dp->fast_out(i); // Control-dependent node
363 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check.
364 if (cd->depends_only_on_test() && _igvn.no_dependent_zero_check(cd)) {
365 assert(cd->in(0) == dp, "");
366 _igvn.replace_input_of(cd, 0, prevdom);
367 if (pin_array_access_nodes) {
368 // Because of Loop Predication, Loads and range check Cast nodes that are control dependent on this range
369 // check (that is about to be removed) now depend on multiple dominating Hoisted Check Predicates. After the
370 // removal of this range check, these control dependent nodes end up at the lowest/nearest dominating predicate
371 // in the graph. To ensure that these Loads/Casts do not float above any of the dominating checks (even when the
372 // lowest dominating check is later replaced by yet another dominating check), we need to pin them at the lowest
373 // dominating check.
374 Node* clone = cd->pin_array_access_node();
375 if (clone != nullptr) {
376 clone = _igvn.register_new_node_with_optimizer(clone, cd);
377 _igvn.replace_node(cd, clone);
378 cd = clone;
379 }
380 }
381 set_early_ctrl(cd, false);
382 IdealLoopTree* new_loop = get_loop(get_ctrl(cd));
383 if (old_loop != new_loop) {
384 if (!old_loop->_child) {
385 old_loop->_body.yank(cd);
386 }
387 if (!new_loop->_child) {
388 new_loop->_body.push(cd);
389 }
390 }
391 --i;
392 --imax;
393 }
394 }
395 }
396
397 //------------------------------has_local_phi_input----------------------------
398 // Return TRUE if 'n' has Phi inputs from its local block and no other
399 // block-local inputs (all non-local-phi inputs come from earlier blocks)
400 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
401 Node *n_ctrl = get_ctrl(n);
402 // See if some inputs come from a Phi in this block, or from before
403 // this block.
404 uint i;
405 for( i = 1; i < n->req(); i++ ) {
406 Node *phi = n->in(i);
407 if( phi->is_Phi() && phi->in(0) == n_ctrl )
408 break;
409 }
410 if( i >= n->req() )
411 return nullptr; // No Phi inputs; nowhere to clone thru
412
413 // Check for inputs created between 'n' and the Phi input. These
414 // must split as well; they have already been given the chance
415 // (courtesy of a post-order visit) and since they did not we must
416 // recover the 'cost' of splitting them by being very profitable
417 // when splitting 'n'. Since this is unlikely we simply give up.
418 for( i = 1; i < n->req(); i++ ) {
419 Node *m = n->in(i);
420 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
421 // We allow the special case of AddP's with no local inputs.
422 // This allows us to split-up address expressions.
423 if (m->is_AddP() &&
424 get_ctrl(m->in(AddPNode::Base)) != n_ctrl &&
425 get_ctrl(m->in(AddPNode::Address)) != n_ctrl &&
426 get_ctrl(m->in(AddPNode::Offset)) != n_ctrl) {
427 // Move the AddP up to the dominating point. That's fine because control of m's inputs
428 // must dominate get_ctrl(m) == n_ctrl and we just checked that the input controls are != n_ctrl.
429 Node* c = find_non_split_ctrl(idom(n_ctrl));
430 if (c->is_OuterStripMinedLoop()) {
431 c->as_Loop()->verify_strip_mined(1);
432 c = c->in(LoopNode::EntryControl);
433 }
434 set_ctrl_and_loop(m, c);
435 continue;
436 }
437 return nullptr;
438 }
439 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
440 }
441
442 return n_ctrl;
443 }
444
445 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
446 Node* PhaseIdealLoop::remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt) {
447 assert(bt == T_INT || bt == T_LONG, "only for integers");
448 int n_op = n->Opcode();
449
450 if (n_op == Op_LShift(bt)) {
451 // Scale is loop invariant
452 Node* scale = n->in(2);
453 Node* scale_ctrl = get_ctrl(scale);
454 IdealLoopTree* scale_loop = get_loop(scale_ctrl);
455 if (n_loop == scale_loop || !scale_loop->is_member(n_loop)) {
456 return nullptr;
457 }
458 const TypeInt* scale_t = scale->bottom_type()->isa_int();
459 if (scale_t != nullptr && scale_t->is_con() && scale_t->get_con() >= 16) {
460 return nullptr; // Dont bother with byte/short masking
461 }
462 // Add must vary with loop (else shift would be loop-invariant)
463 Node* add = n->in(1);
464 Node* add_ctrl = get_ctrl(add);
465 IdealLoopTree* add_loop = get_loop(add_ctrl);
466 if (n_loop != add_loop) {
467 return nullptr; // happens w/ evil ZKM loops
468 }
469
470 // Convert I-V into I+ (0-V); same for V-I
471 if (add->Opcode() == Op_Sub(bt) &&
472 _igvn.type(add->in(1)) != TypeInteger::zero(bt)) {
473 assert(add->Opcode() == Op_SubI || add->Opcode() == Op_SubL, "");
474 Node* zero = _igvn.integercon(0, bt);
475 set_ctrl(zero, C->root());
476 Node* neg = SubNode::make(zero, add->in(2), bt);
477 register_new_node(neg, get_ctrl(add->in(2)));
478 add = AddNode::make(add->in(1), neg, bt);
479 register_new_node(add, add_ctrl);
480 }
481 if (add->Opcode() != Op_Add(bt)) return nullptr;
482 assert(add->Opcode() == Op_AddI || add->Opcode() == Op_AddL, "");
483 // See if one add input is loop invariant
484 Node* add_var = add->in(1);
485 Node* add_var_ctrl = get_ctrl(add_var);
486 IdealLoopTree* add_var_loop = get_loop(add_var_ctrl);
487 Node* add_invar = add->in(2);
488 Node* add_invar_ctrl = get_ctrl(add_invar);
489 IdealLoopTree* add_invar_loop = get_loop(add_invar_ctrl);
490 if (add_invar_loop == n_loop) {
491 // Swap to find the invariant part
492 add_invar = add_var;
493 add_invar_ctrl = add_var_ctrl;
494 add_invar_loop = add_var_loop;
495 add_var = add->in(2);
496 } else if (add_var_loop != n_loop) { // Else neither input is loop invariant
497 return nullptr;
498 }
499 if (n_loop == add_invar_loop || !add_invar_loop->is_member(n_loop)) {
500 return nullptr; // No invariant part of the add?
501 }
502
503 // Yes! Reshape address expression!
504 Node* inv_scale = LShiftNode::make(add_invar, scale, bt);
505 Node* inv_scale_ctrl =
506 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
507 add_invar_ctrl : scale_ctrl;
508 register_new_node(inv_scale, inv_scale_ctrl);
509 Node* var_scale = LShiftNode::make(add_var, scale, bt);
510 register_new_node(var_scale, n_ctrl);
511 Node* var_add = AddNode::make(var_scale, inv_scale, bt);
512 register_new_node(var_add, n_ctrl);
513 _igvn.replace_node(n, var_add);
514 return var_add;
515 }
516 return nullptr;
517 }
518
519 //------------------------------remix_address_expressions----------------------
520 // Rework addressing expressions to get the most loop-invariant stuff
521 // moved out. We'd like to do all associative operators, but it's especially
522 // important (common) to do address expressions.
523 Node* PhaseIdealLoop::remix_address_expressions(Node* n) {
524 if (!has_ctrl(n)) return nullptr;
525 Node* n_ctrl = get_ctrl(n);
526 IdealLoopTree* n_loop = get_loop(n_ctrl);
527
528 // See if 'n' mixes loop-varying and loop-invariant inputs and
529 // itself is loop-varying.
530
531 // Only interested in binary ops (and AddP)
532 if (n->req() < 3 || n->req() > 4) return nullptr;
533
534 Node* n1_ctrl = get_ctrl(n->in( 1));
535 Node* n2_ctrl = get_ctrl(n->in( 2));
536 Node* n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
537 IdealLoopTree* n1_loop = get_loop(n1_ctrl);
538 IdealLoopTree* n2_loop = get_loop(n2_ctrl);
539 IdealLoopTree* n3_loop = get_loop(n3_ctrl);
540
541 // Does one of my inputs spin in a tighter loop than self?
542 if ((n_loop->is_member(n1_loop) && n_loop != n1_loop) ||
543 (n_loop->is_member(n2_loop) && n_loop != n2_loop) ||
544 (n_loop->is_member(n3_loop) && n_loop != n3_loop)) {
545 return nullptr; // Leave well enough alone
546 }
547
548 // Is at least one of my inputs loop-invariant?
549 if (n1_loop == n_loop &&
550 n2_loop == n_loop &&
551 n3_loop == n_loop) {
552 return nullptr; // No loop-invariant inputs
553 }
554
555 Node* res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_INT);
556 if (res != nullptr) {
557 return res;
558 }
559 res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_LONG);
560 if (res != nullptr) {
561 return res;
562 }
563
564 int n_op = n->Opcode();
565 // Replace (I+V) with (V+I)
566 if (n_op == Op_AddI ||
567 n_op == Op_AddL ||
568 n_op == Op_AddF ||
569 n_op == Op_AddD ||
570 n_op == Op_MulI ||
571 n_op == Op_MulL ||
572 n_op == Op_MulF ||
573 n_op == Op_MulD) {
574 if (n2_loop == n_loop) {
575 assert(n1_loop != n_loop, "");
576 n->swap_edges(1, 2);
577 }
578 }
579
580 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
581 // but not if I2 is a constant.
582 if (n_op == Op_AddP) {
583 if (n2_loop == n_loop && n3_loop != n_loop) {
584 if (n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con()) {
585 Node* n22_ctrl = get_ctrl(n->in(2)->in(2));
586 Node* n23_ctrl = get_ctrl(n->in(2)->in(3));
587 IdealLoopTree* n22loop = get_loop(n22_ctrl);
588 IdealLoopTree* n23_loop = get_loop(n23_ctrl);
589 if (n22loop != n_loop && n22loop->is_member(n_loop) &&
590 n23_loop == n_loop) {
591 Node* add1 = new AddPNode(n->in(1), n->in(2)->in(2), n->in(3));
592 // Stuff new AddP in the loop preheader
593 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
594 Node* add2 = new AddPNode(n->in(1), add1, n->in(2)->in(3));
595 register_new_node(add2, n_ctrl);
596 _igvn.replace_node(n, add2);
597 return add2;
598 }
599 }
600 }
601
602 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
603 if (n2_loop != n_loop && n3_loop == n_loop) {
604 if (n->in(3)->Opcode() == Op_AddX) {
605 Node* V = n->in(3)->in(1);
606 Node* I = n->in(3)->in(2);
607 if (is_member(n_loop,get_ctrl(V))) {
608 } else {
609 Node *tmp = V; V = I; I = tmp;
610 }
611 if (!is_member(n_loop,get_ctrl(I))) {
612 Node* add1 = new AddPNode(n->in(1), n->in(2), I);
613 // Stuff new AddP in the loop preheader
614 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
615 Node* add2 = new AddPNode(n->in(1), add1, V);
616 register_new_node(add2, n_ctrl);
617 _igvn.replace_node(n, add2);
618 return add2;
619 }
620 }
621 }
622 }
623
624 return nullptr;
625 }
626
627 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1]))
628 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) {
629 assert(n->Opcode() == Op_AddI, "sanity");
630 Node * nn = nullptr;
631 Node * in1 = n->in(1);
632 Node * in2 = n->in(2);
633 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) {
634 IdealLoopTree* loop_n = get_loop(get_ctrl(n));
635 if (loop_n->is_counted() &&
636 loop_n->_head->as_Loop()->is_valid_counted_loop(T_INT) &&
637 Matcher::match_rule_supported(Op_MulAddVS2VI) &&
638 Matcher::match_rule_supported(Op_MulAddS2I)) {
639 Node* mul_in1 = in1->in(1);
640 Node* mul_in2 = in1->in(2);
641 Node* mul_in3 = in2->in(1);
642 Node* mul_in4 = in2->in(2);
643 if (mul_in1->Opcode() == Op_LoadS &&
644 mul_in2->Opcode() == Op_LoadS &&
645 mul_in3->Opcode() == Op_LoadS &&
646 mul_in4->Opcode() == Op_LoadS) {
647 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1));
648 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2));
649 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3));
650 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4));
651 IdealLoopTree* loop5 = get_loop(get_ctrl(in1));
652 IdealLoopTree* loop6 = get_loop(get_ctrl(in2));
653 // All nodes should be in the same counted loop.
654 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 &&
655 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) {
656 Node* adr1 = mul_in1->in(MemNode::Address);
657 Node* adr2 = mul_in2->in(MemNode::Address);
658 Node* adr3 = mul_in3->in(MemNode::Address);
659 Node* adr4 = mul_in4->in(MemNode::Address);
660 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) {
661 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) &&
662 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) {
663 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4);
664 register_new_node(nn, get_ctrl(n));
665 _igvn.replace_node(n, nn);
666 return nn;
667 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) &&
668 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) {
669 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3);
670 register_new_node(nn, get_ctrl(n));
671 _igvn.replace_node(n, nn);
672 return nn;
673 }
674 }
675 }
676 }
677 }
678 }
679 return nn;
680 }
681
682 //------------------------------conditional_move-------------------------------
683 // Attempt to replace a Phi with a conditional move. We have some pretty
684 // strict profitability requirements. All Phis at the merge point must
685 // be converted, so we can remove the control flow. We need to limit the
686 // number of c-moves to a small handful. All code that was in the side-arms
687 // of the CFG diamond is now speculatively executed. This code has to be
688 // "cheap enough". We are pretty much limited to CFG diamonds that merge
689 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
690 Node *PhaseIdealLoop::conditional_move( Node *region ) {
691
692 assert(region->is_Region(), "sanity check");
693 if (region->req() != 3) return nullptr;
694
695 // Check for CFG diamond
696 Node *lp = region->in(1);
697 Node *rp = region->in(2);
698 if (!lp || !rp) return nullptr;
699 Node *lp_c = lp->in(0);
700 if (lp_c == nullptr || lp_c != rp->in(0) || !lp_c->is_If()) return nullptr;
701 IfNode *iff = lp_c->as_If();
702
703 // Check for ops pinned in an arm of the diamond.
704 // Can't remove the control flow in this case
705 if (lp->outcnt() > 1) return nullptr;
706 if (rp->outcnt() > 1) return nullptr;
707
708 IdealLoopTree* r_loop = get_loop(region);
709 assert(r_loop == get_loop(iff), "sanity");
710 // Always convert to CMOVE if all results are used only outside this loop.
711 bool used_inside_loop = (r_loop == _ltree_root);
712
713 // Check profitability
714 int cost = 0;
715 int phis = 0;
716 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
717 Node *out = region->fast_out(i);
718 if (!out->is_Phi()) continue; // Ignore other control edges, etc
719 phis++;
720 PhiNode* phi = out->as_Phi();
721 BasicType bt = phi->type()->basic_type();
722 switch (bt) {
723 case T_DOUBLE:
724 case T_FLOAT:
725 if (C->use_cmove()) {
726 continue; //TODO: maybe we want to add some cost
727 }
728 cost += Matcher::float_cmove_cost(); // Could be very expensive
729 break;
730 case T_LONG: {
731 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
732 }
733 case T_INT: // These all CMOV fine
734 case T_ADDRESS: { // (RawPtr)
735 cost++;
736 break;
737 }
738 case T_NARROWOOP: // Fall through
739 case T_OBJECT: { // Base oops are OK, but not derived oops
740 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
741 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
742 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
743 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
744 // have a Phi for the base here that we convert to a CMOVE all is well
745 // and good. But if the base is dead, we'll not make a CMOVE. Later
746 // the allocator will have to produce a base by creating a CMOVE of the
747 // relevant bases. This puts the allocator in the business of
748 // manufacturing expensive instructions, generally a bad plan.
749 // Just Say No to Conditionally-Moved Derived Pointers.
750 if (tp && tp->offset() != 0)
751 return nullptr;
752 cost++;
753 break;
754 }
755 default:
756 return nullptr; // In particular, can't do memory or I/O
757 }
758 // Add in cost any speculative ops
759 for (uint j = 1; j < region->req(); j++) {
760 Node *proj = region->in(j);
761 Node *inp = phi->in(j);
762 if (inp->isa_InlineType()) {
763 // TODO 8302217 This prevents PhiNode::push_inline_types_through
764 return nullptr;
765 }
766 if (get_ctrl(inp) == proj) { // Found local op
767 cost++;
768 // Check for a chain of dependent ops; these will all become
769 // speculative in a CMOV.
770 for (uint k = 1; k < inp->req(); k++)
771 if (get_ctrl(inp->in(k)) == proj)
772 cost += ConditionalMoveLimit; // Too much speculative goo
773 }
774 }
775 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
776 // This will likely Split-If, a higher-payoff operation.
777 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
778 Node* use = phi->fast_out(k);
779 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
780 cost += ConditionalMoveLimit;
781 // Is there a use inside the loop?
782 // Note: check only basic types since CMoveP is pinned.
783 if (!used_inside_loop && is_java_primitive(bt)) {
784 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
785 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
786 used_inside_loop = true;
787 }
788 }
789 }
790 }//for
791 Node* bol = iff->in(1);
792 if (bol->Opcode() == Op_Opaque4) {
793 return nullptr; // Ignore loop predicate checks (the Opaque4 ensures they will go away)
794 }
795 assert(bol->Opcode() == Op_Bool, "Unexpected node");
796 int cmp_op = bol->in(1)->Opcode();
797 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode
798 return nullptr;
799 }
800 // It is expensive to generate flags from a float compare.
801 // Avoid duplicated float compare.
802 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return nullptr;
803
804 // Ignore cost if CMOVE can be moved outside the loop.
805 if (used_inside_loop && cost >= ConditionalMoveLimit) {
806 return nullptr;
807 }
808 // Check for highly predictable branch. No point in CMOV'ing if
809 // we are going to predict accurately all the time.
810 constexpr float infrequent_prob = PROB_UNLIKELY_MAG(2);
811 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
812 //keep going
813 } else if (iff->_prob < infrequent_prob || iff->_prob > (1.0f - infrequent_prob)) {
814 return nullptr;
815 }
816
817 // --------------
818 // Now replace all Phis with CMOV's
819 Node *cmov_ctrl = iff->in(0);
820 uint flip = (lp->Opcode() == Op_IfTrue);
821 Node_List wq;
822 while (1) {
823 PhiNode* phi = nullptr;
824 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
825 Node *out = region->fast_out(i);
826 if (out->is_Phi()) {
827 phi = out->as_Phi();
828 break;
829 }
830 }
831 if (phi == nullptr || _igvn.type(phi) == Type::TOP) {
832 break;
833 }
834 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
835 // Move speculative ops
836 wq.push(phi);
837 while (wq.size() > 0) {
838 Node *n = wq.pop();
839 for (uint j = 1; j < n->req(); j++) {
840 Node* m = n->in(j);
841 if (m != nullptr && !is_dominator(get_ctrl(m), cmov_ctrl)) {
842 #ifndef PRODUCT
843 if (PrintOpto && VerifyLoopOptimizations) {
844 tty->print(" speculate: ");
845 m->dump();
846 }
847 #endif
848 set_ctrl(m, cmov_ctrl);
849 wq.push(m);
850 }
851 }
852 }
853 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
854 register_new_node( cmov, cmov_ctrl );
855 _igvn.replace_node( phi, cmov );
856 #ifndef PRODUCT
857 if (TraceLoopOpts) {
858 tty->print("CMOV ");
859 r_loop->dump_head();
860 if (Verbose) {
861 bol->in(1)->dump(1);
862 cmov->dump(1);
863 }
864 }
865 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
866 #endif
867 }
868
869 // The useless CFG diamond will fold up later; see the optimization in
870 // RegionNode::Ideal.
871 _igvn._worklist.push(region);
872
873 return iff->in(1);
874 }
875
876 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
877 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
878 Node* u = m->fast_out(i);
879 if (u->is_CFG()) {
880 if (u->is_NeverBranch()) {
881 u = u->as_NeverBranch()->proj_out(0);
882 enqueue_cfg_uses(u, wq);
883 } else {
884 wq.push(u);
885 }
886 }
887 }
888 }
889
890 // Try moving a store out of a loop, right before the loop
891 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
892 // Store has to be first in the loop body
893 IdealLoopTree *n_loop = get_loop(n_ctrl);
894 if (n->is_Store() && n_loop != _ltree_root &&
895 n_loop->is_loop() && n_loop->_head->is_Loop() &&
896 n->in(0) != nullptr) {
897 Node* address = n->in(MemNode::Address);
898 Node* value = n->in(MemNode::ValueIn);
899 Node* mem = n->in(MemNode::Memory);
900 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
901 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
902
903 // - address and value must be loop invariant
904 // - memory must be a memory Phi for the loop
905 // - Store must be the only store on this memory slice in the
906 // loop: if there's another store following this one then value
907 // written at iteration i by the second store could be overwritten
908 // at iteration i+n by the first store: it's not safe to move the
909 // first store out of the loop
910 // - nothing must observe the memory Phi: it guarantees no read
911 // before the store, we are also guaranteed the store post
912 // dominates the loop head (ignoring a possible early
913 // exit). Otherwise there would be extra Phi involved between the
914 // loop's Phi and the store.
915 // - there must be no early exit from the loop before the Store
916 // (such an exit most of the time would be an extra use of the
917 // memory Phi but sometimes is a bottom memory Phi that takes the
918 // store as input).
919
920 if (!n_loop->is_member(address_loop) &&
921 !n_loop->is_member(value_loop) &&
922 mem->is_Phi() && mem->in(0) == n_loop->_head &&
923 mem->outcnt() == 1 &&
924 mem->in(LoopNode::LoopBackControl) == n) {
925
926 assert(n_loop->_tail != nullptr, "need a tail");
927 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
928
929 // Verify that there's no early exit of the loop before the store.
930 bool ctrl_ok = false;
931 {
932 // Follow control from loop head until n, we exit the loop or
933 // we reach the tail
934 ResourceMark rm;
935 Unique_Node_List wq;
936 wq.push(n_loop->_head);
937
938 for (uint next = 0; next < wq.size(); ++next) {
939 Node *m = wq.at(next);
940 if (m == n->in(0)) {
941 ctrl_ok = true;
942 continue;
943 }
944 assert(!has_ctrl(m), "should be CFG");
945 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
946 ctrl_ok = false;
947 break;
948 }
949 enqueue_cfg_uses(m, wq);
950 if (wq.size() > 10) {
951 ctrl_ok = false;
952 break;
953 }
954 }
955 }
956 if (ctrl_ok) {
957 // move the Store
958 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
959 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
960 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
961 // Disconnect the phi now. An empty phi can confuse other
962 // optimizations in this pass of loop opts.
963 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
964 n_loop->_body.yank(mem);
965
966 set_ctrl_and_loop(n, n->in(0));
967
968 return n;
969 }
970 }
971 }
972 return nullptr;
973 }
974
975 // Try moving a store out of a loop, right after the loop
976 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
977 if (n->is_Store() && n->in(0) != nullptr) {
978 Node *n_ctrl = get_ctrl(n);
979 IdealLoopTree *n_loop = get_loop(n_ctrl);
980 // Store must be in a loop
981 if (n_loop != _ltree_root && !n_loop->_irreducible) {
982 Node* address = n->in(MemNode::Address);
983 Node* value = n->in(MemNode::ValueIn);
984 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
985 // address must be loop invariant
986 if (!n_loop->is_member(address_loop)) {
987 // Store must be last on this memory slice in the loop and
988 // nothing in the loop must observe it
989 Node* phi = nullptr;
990 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
991 Node* u = n->fast_out(i);
992 if (has_ctrl(u)) { // control use?
993 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
994 if (!n_loop->is_member(u_loop)) {
995 continue;
996 }
997 if (u->is_Phi() && u->in(0) == n_loop->_head) {
998 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
999 // multiple phis on the same slice are possible
1000 if (phi != nullptr) {
1001 return;
1002 }
1003 phi = u;
1004 continue;
1005 }
1006 }
1007 return;
1008 }
1009 if (phi != nullptr) {
1010 // Nothing in the loop before the store (next iteration)
1011 // must observe the stored value
1012 bool mem_ok = true;
1013 {
1014 ResourceMark rm;
1015 Unique_Node_List wq;
1016 wq.push(phi);
1017 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
1018 Node *m = wq.at(next);
1019 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
1020 Node* u = m->fast_out(i);
1021 if (u->is_Store() || u->is_Phi()) {
1022 if (u != n) {
1023 wq.push(u);
1024 mem_ok = (wq.size() <= 10);
1025 }
1026 } else {
1027 mem_ok = false;
1028 break;
1029 }
1030 }
1031 }
1032 }
1033 if (mem_ok) {
1034 // Move the store out of the loop if the LCA of all
1035 // users (except for the phi) is outside the loop.
1036 Node* hook = new Node(1);
1037 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead
1038 _igvn.rehash_node_delayed(phi);
1039 int count = phi->replace_edge(n, hook, &_igvn);
1040 assert(count > 0, "inconsistent phi");
1041
1042 // Compute latest point this store can go
1043 Node* lca = get_late_ctrl(n, get_ctrl(n));
1044 if (lca->is_OuterStripMinedLoop()) {
1045 lca = lca->in(LoopNode::EntryControl);
1046 }
1047 if (n_loop->is_member(get_loop(lca))) {
1048 // LCA is in the loop - bail out
1049 _igvn.replace_node(hook, n);
1050 return;
1051 }
1052 #ifdef ASSERT
1053 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
1054 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
1055 n_loop->_head->as_Loop()->verify_strip_mined(1);
1056 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
1057 IdealLoopTree* outer_loop = get_loop(outer);
1058 assert(n_loop->_parent == outer_loop, "broken loop tree");
1059 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
1060 }
1061 #endif
1062 lca = place_outside_loop(lca, n_loop);
1063 assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop");
1064 assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch(), "must not be moved into inner loop");
1065
1066 // Move store out of the loop
1067 _igvn.replace_node(hook, n->in(MemNode::Memory));
1068 _igvn.replace_input_of(n, 0, lca);
1069 set_ctrl_and_loop(n, lca);
1070
1071 // Disconnect the phi now. An empty phi can confuse other
1072 // optimizations in this pass of loop opts..
1073 if (phi->in(LoopNode::LoopBackControl) == phi) {
1074 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
1075 n_loop->_body.yank(phi);
1076 }
1077 }
1078 }
1079 }
1080 }
1081 }
1082 }
1083
1084 // We can't use immutable memory for the flat array check because we are loading the mark word which is
1085 // mutable. Although the bits we are interested in are immutable (we check for markWord::unlocked_value),
1086 // we need to use raw memory to not break anti dependency analysis. Below code will attempt to still move
1087 // flat array checks out of loops, mainly to enable loop unswitching.
1088 void PhaseIdealLoop::move_flat_array_check_out_of_loop(Node* n) {
1089 // Skip checks for more than one array
1090 if (n->req() > 3) {
1091 return;
1092 }
1093 Node* mem = n->in(FlatArrayCheckNode::Memory);
1094 Node* array = n->in(FlatArrayCheckNode::ArrayOrKlass)->uncast();
1095 IdealLoopTree* check_loop = get_loop(get_ctrl(n));
1096 IdealLoopTree* ary_loop = get_loop(get_ctrl(array));
1097
1098 // Check if array is loop invariant
1099 if (!check_loop->is_member(ary_loop)) {
1100 // Walk up memory graph from the check until we leave the loop
1101 VectorSet wq;
1102 wq.set(mem->_idx);
1103 while (check_loop->is_member(get_loop(ctrl_or_self(mem)))) {
1104 if (mem->is_Phi()) {
1105 mem = mem->in(1);
1106 } else if (mem->is_MergeMem()) {
1107 mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1108 } else if (mem->is_Proj()) {
1109 mem = mem->in(0);
1110 } else if (mem->is_MemBar() || mem->is_SafePoint()) {
1111 mem = mem->in(TypeFunc::Memory);
1112 } else if (mem->is_Store() || mem->is_LoadStore() || mem->is_ClearArray()) {
1113 mem = mem->in(MemNode::Memory);
1114 } else {
1115 #ifdef ASSERT
1116 mem->dump();
1117 #endif
1118 ShouldNotReachHere();
1119 }
1120 if (wq.test_set(mem->_idx)) {
1121 return;
1122 }
1123 }
1124 // Replace memory input and re-compute ctrl to move the check out of the loop
1125 _igvn.replace_input_of(n, 1, mem);
1126 set_ctrl_and_loop(n, get_early_ctrl(n));
1127 Node* bol = n->unique_out();
1128 set_ctrl_and_loop(bol, get_early_ctrl(bol));
1129 }
1130 }
1131
1132 //------------------------------split_if_with_blocks_pre-----------------------
1133 // Do the real work in a non-recursive function. Data nodes want to be
1134 // cloned in the pre-order so they can feed each other nicely.
1135 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
1136 // Cloning these guys is unlikely to win
1137 int n_op = n->Opcode();
1138 if (n_op == Op_MergeMem) {
1139 return n;
1140 }
1141 if (n->is_Proj()) {
1142 return n;
1143 }
1144
1145 if (n->isa_FlatArrayCheck()) {
1146 move_flat_array_check_out_of_loop(n);
1147 return n;
1148 }
1149
1150 // Do not clone-up CmpFXXX variations, as these are always
1151 // followed by a CmpI
1152 if (n->is_Cmp()) {
1153 return n;
1154 }
1155 // Attempt to use a conditional move instead of a phi/branch
1156 if (ConditionalMoveLimit > 0 && n_op == Op_Region) {
1157 Node *cmov = conditional_move( n );
1158 if (cmov) {
1159 return cmov;
1160 }
1161 }
1162 if (n->is_CFG() || n->is_LoadStore()) {
1163 return n;
1164 }
1165 if (n->is_Opaque1()) { // Opaque nodes cannot be mod'd
1166 if (!C->major_progress()) { // If chance of no more loop opts...
1167 _igvn._worklist.push(n); // maybe we'll remove them
1168 }
1169 return n;
1170 }
1171
1172 if (n->is_Con()) {
1173 return n; // No cloning for Con nodes
1174 }
1175
1176 Node *n_ctrl = get_ctrl(n);
1177 if (!n_ctrl) {
1178 return n; // Dead node
1179 }
1180
1181 Node* res = try_move_store_before_loop(n, n_ctrl);
1182 if (res != nullptr) {
1183 return n;
1184 }
1185
1186 // Attempt to remix address expressions for loop invariants
1187 Node *m = remix_address_expressions( n );
1188 if( m ) return m;
1189
1190 if (n_op == Op_AddI) {
1191 Node *nn = convert_add_to_muladd( n );
1192 if ( nn ) return nn;
1193 }
1194
1195 if (n->is_ConstraintCast()) {
1196 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
1197 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
1198 // Node control inputs don't necessarily agree with loop control info (due to
1199 // transformations happened in between), thus additional dominance check is needed
1200 // to keep loop info valid.
1201 if (dom_cast != nullptr && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
1202 _igvn.replace_node(n, dom_cast);
1203 return dom_cast;
1204 }
1205 }
1206
1207 // Determine if the Node has inputs from some local Phi.
1208 // Returns the block to clone thru.
1209 Node *n_blk = has_local_phi_input( n );
1210 if( !n_blk ) return n;
1211
1212 // Do not clone the trip counter through on a CountedLoop
1213 // (messes up the canonical shape).
1214 if (((n_blk->is_CountedLoop() || (n_blk->is_Loop() && n_blk->as_Loop()->is_loop_nest_inner_loop())) && n->Opcode() == Op_AddI) ||
1215 (n_blk->is_LongCountedLoop() && n->Opcode() == Op_AddL)) {
1216 return n;
1217 }
1218 // Pushing a shift through the iv Phi can get in the way of addressing optimizations or range check elimination
1219 if (n_blk->is_BaseCountedLoop() && n->Opcode() == Op_LShift(n_blk->as_BaseCountedLoop()->bt()) &&
1220 n->in(1) == n_blk->as_BaseCountedLoop()->phi()) {
1221 return n;
1222 }
1223
1224 // Check for having no control input; not pinned. Allow
1225 // dominating control.
1226 if (n->in(0)) {
1227 Node *dom = idom(n_blk);
1228 if (dom_lca(n->in(0), dom) != n->in(0)) {
1229 return n;
1230 }
1231 }
1232 // Policy: when is it profitable. You must get more wins than
1233 // policy before it is considered profitable. Policy is usually 0,
1234 // so 1 win is considered profitable. Big merges will require big
1235 // cloning, so get a larger policy.
1236 int policy = n_blk->req() >> 2;
1237
1238 // If the loop is a candidate for range check elimination,
1239 // delay splitting through it's phi until a later loop optimization
1240 if (n_blk->is_BaseCountedLoop()) {
1241 IdealLoopTree *lp = get_loop(n_blk);
1242 if (lp && lp->_rce_candidate) {
1243 return n;
1244 }
1245 }
1246
1247 if (must_throttle_split_if()) return n;
1248
1249 // Split 'n' through the merge point if it is profitable
1250 Node *phi = split_thru_phi( n, n_blk, policy );
1251 if (!phi) return n;
1252
1253 // Found a Phi to split thru!
1254 // Replace 'n' with the new phi
1255 _igvn.replace_node( n, phi );
1256 // Moved a load around the loop, 'en-registering' something.
1257 if (n_blk->is_Loop() && n->is_Load() &&
1258 !phi->in(LoopNode::LoopBackControl)->is_Load())
1259 C->set_major_progress();
1260
1261 return phi;
1262 }
1263
1264 static bool merge_point_too_heavy(Compile* C, Node* region) {
1265 // Bail out if the region and its phis have too many users.
1266 int weight = 0;
1267 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1268 weight += region->fast_out(i)->outcnt();
1269 }
1270 int nodes_left = C->max_node_limit() - C->live_nodes();
1271 if (weight * 8 > nodes_left) {
1272 if (PrintOpto) {
1273 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
1274 }
1275 return true;
1276 } else {
1277 return false;
1278 }
1279 }
1280
1281 static bool merge_point_safe(Node* region) {
1282 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1283 // having a PhiNode input. This sidesteps the dangerous case where the split
1284 // ConvI2LNode may become TOP if the input Value() does not
1285 // overlap the ConvI2L range, leaving a node which may not dominate its
1286 // uses.
1287 // A better fix for this problem can be found in the BugTraq entry, but
1288 // expediency for Mantis demands this hack.
1289 #ifdef _LP64
1290 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1291 Node* n = region->fast_out(i);
1292 if (n->is_Phi()) {
1293 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1294 Node* m = n->fast_out(j);
1295 if (m->Opcode() == Op_ConvI2L)
1296 return false;
1297 if (m->is_CastII()) {
1298 return false;
1299 }
1300 }
1301 }
1302 }
1303 #endif
1304 return true;
1305 }
1306
1307
1308 //------------------------------place_outside_loop---------------------------------
1309 // Place some computation outside of this loop on the path to the use passed as argument
1310 Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) const {
1311 Node* head = loop->_head;
1312 assert(!loop->is_member(get_loop(useblock)), "must be outside loop");
1313 if (head->is_Loop() && head->as_Loop()->is_strip_mined()) {
1314 loop = loop->_parent;
1315 assert(loop->_head->is_OuterStripMinedLoop(), "malformed strip mined loop");
1316 }
1317
1318 // Pick control right outside the loop
1319 for (;;) {
1320 Node* dom = idom(useblock);
1321 if (loop->is_member(get_loop(dom)) ||
1322 // NeverBranch nodes are not assigned to the loop when constructed
1323 (dom->is_NeverBranch() && loop->is_member(get_loop(dom->in(0))))) {
1324 break;
1325 }
1326 useblock = dom;
1327 }
1328 assert(find_non_split_ctrl(useblock) == useblock, "should be non split control");
1329 return useblock;
1330 }
1331
1332
1333 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1334 if (!n->is_If() || n->is_BaseCountedLoopEnd()) {
1335 return false;
1336 }
1337 if (!n->in(0)->is_Region()) {
1338 return false;
1339 }
1340
1341 Node* region = n->in(0);
1342 Node* dom = idom(region);
1343 if (!dom->is_If() || !n->as_If()->same_condition(dom, &_igvn)) {
1344 return false;
1345 }
1346 IfNode* dom_if = dom->as_If();
1347 Node* proj_true = dom_if->proj_out(1);
1348 Node* proj_false = dom_if->proj_out(0);
1349
1350 for (uint i = 1; i < region->req(); i++) {
1351 if (is_dominator(proj_true, region->in(i))) {
1352 continue;
1353 }
1354 if (is_dominator(proj_false, region->in(i))) {
1355 continue;
1356 }
1357 return false;
1358 }
1359
1360 return true;
1361 }
1362
1363
1364 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) {
1365 if (must_throttle_split_if()) {
1366 return false;
1367 }
1368
1369 // Do not do 'split-if' if irreducible loops are present.
1370 if (_has_irreducible_loops) {
1371 return false;
1372 }
1373
1374 if (merge_point_too_heavy(C, n_ctrl)) {
1375 return false;
1376 }
1377
1378 // Do not do 'split-if' if some paths are dead. First do dead code
1379 // elimination and then see if its still profitable.
1380 for (uint i = 1; i < n_ctrl->req(); i++) {
1381 if (n_ctrl->in(i) == C->top()) {
1382 return false;
1383 }
1384 }
1385
1386 // If trying to do a 'Split-If' at the loop head, it is only
1387 // profitable if the cmp folds up on BOTH paths. Otherwise we
1388 // risk peeling a loop forever.
1389
1390 // CNC - Disabled for now. Requires careful handling of loop
1391 // body selection for the cloned code. Also, make sure we check
1392 // for any input path not being in the same loop as n_ctrl. For
1393 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1394 // because the alternative loop entry points won't be converted
1395 // into LoopNodes.
1396 IdealLoopTree *n_loop = get_loop(n_ctrl);
1397 for (uint j = 1; j < n_ctrl->req(); j++) {
1398 if (get_loop(n_ctrl->in(j)) != n_loop) {
1399 return false;
1400 }
1401 }
1402
1403 // Check for safety of the merge point.
1404 if (!merge_point_safe(n_ctrl)) {
1405 return false;
1406 }
1407
1408 return true;
1409 }
1410
1411 // Detect if the node is the inner strip-mined loop
1412 // Return: null if it's not the case, or the exit of outer strip-mined loop
1413 static Node* is_inner_of_stripmined_loop(const Node* out) {
1414 Node* out_le = nullptr;
1415
1416 if (out->is_CountedLoopEnd()) {
1417 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode();
1418
1419 if (loop != nullptr && loop->is_strip_mined()) {
1420 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit();
1421 }
1422 }
1423
1424 return out_le;
1425 }
1426
1427 bool PhaseIdealLoop::flat_array_element_type_check(Node *n) {
1428 // If the CmpP is a subtype check for a value that has just been
1429 // loaded from an array, the subtype check guarantees the value
1430 // can't be stored in a flat array and the load of the value
1431 // happens with a flat array check then: push the type check
1432 // through the phi of the flat array check. This needs special
1433 // logic because the subtype check's input is not a phi but a
1434 // LoadKlass that must first be cloned through the phi.
1435 if (n->Opcode() != Op_CmpP) {
1436 return false;
1437 }
1438
1439 Node* klassptr = n->in(1);
1440 Node* klasscon = n->in(2);
1441
1442 if (klassptr->is_DecodeNarrowPtr()) {
1443 klassptr = klassptr->in(1);
1444 }
1445
1446 if (klassptr->Opcode() != Op_LoadKlass && klassptr->Opcode() != Op_LoadNKlass) {
1447 return false;
1448 }
1449
1450 if (!klasscon->is_Con()) {
1451 return false;
1452 }
1453
1454 Node* addr = klassptr->in(MemNode::Address);
1455
1456 if (!addr->is_AddP()) {
1457 return false;
1458 }
1459
1460 intptr_t offset;
1461 Node* obj = AddPNode::Ideal_base_and_offset(addr, &_igvn, offset);
1462
1463 if (obj == nullptr) {
1464 return false;
1465 }
1466
1467 assert(obj != nullptr && addr->in(AddPNode::Base) == addr->in(AddPNode::Address), "malformed AddP?");
1468 if (obj->Opcode() == Op_CastPP) {
1469 obj = obj->in(1);
1470 }
1471
1472 if (!obj->is_Phi()) {
1473 return false;
1474 }
1475
1476 Node* region = obj->in(0);
1477
1478 Node* phi = PhiNode::make_blank(region, n->in(1));
1479 for (uint i = 1; i < region->req(); i++) {
1480 Node* in = obj->in(i);
1481 Node* ctrl = region->in(i);
1482 if (addr->in(AddPNode::Base) != obj) {
1483 Node* cast = addr->in(AddPNode::Base);
1484 assert(cast->Opcode() == Op_CastPP && cast->in(0) != nullptr, "inconsistent subgraph");
1485 Node* cast_clone = cast->clone();
1486 cast_clone->set_req(0, ctrl);
1487 cast_clone->set_req(1, in);
1488 register_new_node(cast_clone, ctrl);
1489 const Type* tcast = cast_clone->Value(&_igvn);
1490 _igvn.set_type(cast_clone, tcast);
1491 cast_clone->as_Type()->set_type(tcast);
1492 in = cast_clone;
1493 }
1494 Node* addr_clone = addr->clone();
1495 addr_clone->set_req(AddPNode::Base, in);
1496 addr_clone->set_req(AddPNode::Address, in);
1497 register_new_node(addr_clone, ctrl);
1498 _igvn.set_type(addr_clone, addr_clone->Value(&_igvn));
1499 Node* klassptr_clone = klassptr->clone();
1500 klassptr_clone->set_req(2, addr_clone);
1501 register_new_node(klassptr_clone, ctrl);
1502 _igvn.set_type(klassptr_clone, klassptr_clone->Value(&_igvn));
1503 if (klassptr != n->in(1)) {
1504 Node* decode = n->in(1);
1505 assert(decode->is_DecodeNarrowPtr(), "inconsistent subgraph");
1506 Node* decode_clone = decode->clone();
1507 decode_clone->set_req(1, klassptr_clone);
1508 register_new_node(decode_clone, ctrl);
1509 _igvn.set_type(decode_clone, decode_clone->Value(&_igvn));
1510 klassptr_clone = decode_clone;
1511 }
1512 phi->set_req(i, klassptr_clone);
1513 }
1514 register_new_node(phi, region);
1515 Node* orig = n->in(1);
1516 _igvn.replace_input_of(n, 1, phi);
1517 split_if_with_blocks_post(n);
1518 if (n->outcnt() != 0) {
1519 _igvn.replace_input_of(n, 1, orig);
1520 _igvn.remove_dead_node(phi);
1521 }
1522 return true;
1523 }
1524
1525 //------------------------------split_if_with_blocks_post----------------------
1526 // Do the real work in a non-recursive function. CFG hackery wants to be
1527 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1528 // info.
1529 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1530
1531 if (flat_array_element_type_check(n)) {
1532 return;
1533 }
1534
1535 // Cloning Cmp through Phi's involves the split-if transform.
1536 // FastLock is not used by an If
1537 if (n->is_Cmp() && !n->is_FastLock()) {
1538 Node *n_ctrl = get_ctrl(n);
1539 // Determine if the Node has inputs from some local Phi.
1540 // Returns the block to clone thru.
1541 Node *n_blk = has_local_phi_input(n);
1542 if (n_blk != n_ctrl) {
1543 return;
1544 }
1545
1546 if (!can_split_if(n_ctrl)) {
1547 return;
1548 }
1549
1550 if (n->outcnt() != 1) {
1551 return; // Multiple bool's from 1 compare?
1552 }
1553 Node *bol = n->unique_out();
1554 assert(bol->is_Bool(), "expect a bool here");
1555 if (bol->outcnt() != 1) {
1556 return;// Multiple branches from 1 compare?
1557 }
1558 Node *iff = bol->unique_out();
1559
1560 // Check some safety conditions
1561 if (iff->is_If()) { // Classic split-if?
1562 if (iff->in(0) != n_ctrl) {
1563 return; // Compare must be in same blk as if
1564 }
1565 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1566 // Can't split CMove with different control.
1567 if (get_ctrl(iff) != n_ctrl) {
1568 return;
1569 }
1570 if (get_ctrl(iff->in(2)) == n_ctrl ||
1571 get_ctrl(iff->in(3)) == n_ctrl) {
1572 return; // Inputs not yet split-up
1573 }
1574 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1575 return; // Loop-invar test gates loop-varying CMOVE
1576 }
1577 } else {
1578 return; // some other kind of node, such as an Allocate
1579 }
1580
1581 // When is split-if profitable? Every 'win' on means some control flow
1582 // goes dead, so it's almost always a win.
1583 int policy = 0;
1584 // Split compare 'n' through the merge point if it is profitable
1585 Node *phi = split_thru_phi( n, n_ctrl, policy);
1586 if (!phi) {
1587 return;
1588 }
1589
1590 // Found a Phi to split thru!
1591 // Replace 'n' with the new phi
1592 _igvn.replace_node(n, phi);
1593
1594 // Now split the bool up thru the phi
1595 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1596 guarantee(bolphi != nullptr, "null boolean phi node");
1597
1598 _igvn.replace_node(bol, bolphi);
1599 assert(iff->in(1) == bolphi, "");
1600
1601 if (bolphi->Value(&_igvn)->singleton()) {
1602 return;
1603 }
1604
1605 // Conditional-move? Must split up now
1606 if (!iff->is_If()) {
1607 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1608 _igvn.replace_node(iff, cmovphi);
1609 return;
1610 }
1611
1612 // Now split the IF
1613 C->print_method(PHASE_BEFORE_SPLIT_IF, 4, iff);
1614 if ((PrintOpto && VerifyLoopOptimizations) || TraceLoopOpts) {
1615 tty->print_cr("Split-If");
1616 }
1617 do_split_if(iff);
1618 C->print_method(PHASE_AFTER_SPLIT_IF, 4, iff);
1619 return;
1620 }
1621
1622 // Two identical ifs back to back can be merged
1623 if (try_merge_identical_ifs(n)) {
1624 return;
1625 }
1626
1627 // Check for an IF ready to split; one that has its
1628 // condition codes input coming from a Phi at the block start.
1629 int n_op = n->Opcode();
1630
1631 // Check for an IF being dominated by another IF same test
1632 if (n_op == Op_If ||
1633 n_op == Op_RangeCheck) {
1634 Node *bol = n->in(1);
1635 uint max = bol->outcnt();
1636 // Check for same test used more than once?
1637 if (bol->is_Bool() && (max > 1 || bol->in(1)->is_SubTypeCheck())) {
1638 // Search up IDOMs to see if this IF is dominated.
1639 Node* cmp = bol->in(1);
1640 Node *cutoff = cmp->is_SubTypeCheck() ? dom_lca(get_ctrl(cmp->in(1)), get_ctrl(cmp->in(2))) : get_ctrl(bol);
1641
1642 // Now search up IDOMs till cutoff, looking for a dominating test
1643 Node *prevdom = n;
1644 Node *dom = idom(prevdom);
1645 while (dom != cutoff) {
1646 if (dom->req() > 1 && n->as_If()->same_condition(dom, &_igvn) && prevdom->in(0) == dom &&
1647 safe_for_if_replacement(dom)) {
1648 // It's invalid to move control dependent data nodes in the inner
1649 // strip-mined loop, because:
1650 // 1) break validation of LoopNode::verify_strip_mined()
1651 // 2) move code with side-effect in strip-mined loop
1652 // Move to the exit of outer strip-mined loop in that case.
1653 Node* out_le = is_inner_of_stripmined_loop(dom);
1654 if (out_le != nullptr) {
1655 prevdom = out_le;
1656 }
1657 // Replace the dominated test with an obvious true or false.
1658 // Place it on the IGVN worklist for later cleanup.
1659 C->set_major_progress();
1660 dominated_by(prevdom->as_IfProj(), n->as_If());
1661 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
1662 return;
1663 }
1664 prevdom = dom;
1665 dom = idom(prevdom);
1666 }
1667 }
1668 }
1669
1670 try_sink_out_of_loop(n);
1671
1672 try_move_store_after_loop(n);
1673
1674 // Remove multiple allocations of the same inline type
1675 if (n->is_InlineType()) {
1676 n->as_InlineType()->remove_redundant_allocations(this);
1677 }
1678 }
1679
1680 // Transform:
1681 //
1682 // if (some_condition) {
1683 // // body 1
1684 // } else {
1685 // // body 2
1686 // }
1687 // if (some_condition) {
1688 // // body 3
1689 // } else {
1690 // // body 4
1691 // }
1692 //
1693 // into:
1694 //
1695 //
1696 // if (some_condition) {
1697 // // body 1
1698 // // body 3
1699 // } else {
1700 // // body 2
1701 // // body 4
1702 // }
1703 bool PhaseIdealLoop::try_merge_identical_ifs(Node* n) {
1704 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1705 Node *n_ctrl = n->in(0);
1706 IfNode* dom_if = idom(n_ctrl)->as_If();
1707 if (n->in(1) != dom_if->in(1)) {
1708 assert(n->in(1)->in(1)->is_SubTypeCheck() &&
1709 (n->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr ||
1710 dom_if->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr), "only for subtype checks with profile data attached");
1711 _igvn.replace_input_of(n, 1, dom_if->in(1));
1712 }
1713 ProjNode* dom_proj_true = dom_if->proj_out(1);
1714 ProjNode* dom_proj_false = dom_if->proj_out(0);
1715
1716 // Now split the IF
1717 RegionNode* new_false_region;
1718 RegionNode* new_true_region;
1719 do_split_if(n, &new_false_region, &new_true_region);
1720 assert(new_false_region->req() == new_true_region->req(), "");
1721 #ifdef ASSERT
1722 for (uint i = 1; i < new_false_region->req(); ++i) {
1723 assert(new_false_region->in(i)->in(0) == new_true_region->in(i)->in(0), "unexpected shape following split if");
1724 assert(i == new_false_region->req() - 1 || new_false_region->in(i)->in(0)->in(1) == new_false_region->in(i + 1)->in(0)->in(1), "unexpected shape following split if");
1725 }
1726 #endif
1727 assert(new_false_region->in(1)->in(0)->in(1) == dom_if->in(1), "dominating if and dominated if after split must share test");
1728
1729 // We now have:
1730 // if (some_condition) {
1731 // // body 1
1732 // if (some_condition) {
1733 // body3: // new_true_region
1734 // // body3
1735 // } else {
1736 // goto body4;
1737 // }
1738 // } else {
1739 // // body 2
1740 // if (some_condition) {
1741 // goto body3;
1742 // } else {
1743 // body4: // new_false_region
1744 // // body4;
1745 // }
1746 // }
1747 //
1748
1749 // clone pinned nodes thru the resulting regions
1750 push_pinned_nodes_thru_region(dom_if, new_true_region);
1751 push_pinned_nodes_thru_region(dom_if, new_false_region);
1752
1753 // Optimize out the cloned ifs. Because pinned nodes were cloned, this also allows a CastPP that would be dependent
1754 // on a projection of n to have the dom_if as a control dependency. We don't want the CastPP to end up with an
1755 // unrelated control dependency.
1756 for (uint i = 1; i < new_false_region->req(); i++) {
1757 if (is_dominator(dom_proj_true, new_false_region->in(i))) {
1758 dominated_by(dom_proj_true->as_IfProj(), new_false_region->in(i)->in(0)->as_If());
1759 } else {
1760 assert(is_dominator(dom_proj_false, new_false_region->in(i)), "bad if");
1761 dominated_by(dom_proj_false->as_IfProj(), new_false_region->in(i)->in(0)->as_If());
1762 }
1763 }
1764 return true;
1765 }
1766 return false;
1767 }
1768
1769 void PhaseIdealLoop::push_pinned_nodes_thru_region(IfNode* dom_if, Node* region) {
1770 for (DUIterator i = region->outs(); region->has_out(i); i++) {
1771 Node* u = region->out(i);
1772 if (!has_ctrl(u) || u->is_Phi() || !u->depends_only_on_test() || !_igvn.no_dependent_zero_check(u)) {
1773 continue;
1774 }
1775 assert(u->in(0) == region, "not a control dependent node?");
1776 uint j = 1;
1777 for (; j < u->req(); ++j) {
1778 Node* in = u->in(j);
1779 if (!is_dominator(ctrl_or_self(in), dom_if)) {
1780 break;
1781 }
1782 }
1783 if (j == u->req()) {
1784 Node *phi = PhiNode::make_blank(region, u);
1785 for (uint k = 1; k < region->req(); ++k) {
1786 Node* clone = u->clone();
1787 clone->set_req(0, region->in(k));
1788 register_new_node(clone, region->in(k));
1789 phi->init_req(k, clone);
1790 }
1791 register_new_node(phi, region);
1792 _igvn.replace_node(u, phi);
1793 --i;
1794 }
1795 }
1796 }
1797
1798 bool PhaseIdealLoop::safe_for_if_replacement(const Node* dom) const {
1799 if (!dom->is_CountedLoopEnd()) {
1800 return true;
1801 }
1802 CountedLoopEndNode* le = dom->as_CountedLoopEnd();
1803 CountedLoopNode* cl = le->loopnode();
1804 if (cl == nullptr) {
1805 return true;
1806 }
1807 if (!cl->is_main_loop()) {
1808 return true;
1809 }
1810 if (cl->is_canonical_loop_entry() == nullptr) {
1811 return true;
1812 }
1813 // Further unrolling is possible so loop exit condition might change
1814 return false;
1815 }
1816
1817 // See if a shared loop-varying computation has no loop-varying uses.
1818 // Happens if something is only used for JVM state in uncommon trap exits,
1819 // like various versions of induction variable+offset. Clone the
1820 // computation per usage to allow it to sink out of the loop.
1821 void PhaseIdealLoop::try_sink_out_of_loop(Node* n) {
1822 if (has_ctrl(n) &&
1823 !n->is_Phi() &&
1824 !n->is_Bool() &&
1825 !n->is_Proj() &&
1826 !n->is_MergeMem() &&
1827 !n->is_CMove() &&
1828 n->Opcode() != Op_Opaque4 &&
1829 !n->is_Type()) {
1830 Node *n_ctrl = get_ctrl(n);
1831 IdealLoopTree *n_loop = get_loop(n_ctrl);
1832
1833 if (n->in(0) != nullptr) {
1834 IdealLoopTree* loop_ctrl = get_loop(n->in(0));
1835 if (n_loop != loop_ctrl && n_loop->is_member(loop_ctrl)) {
1836 // n has a control input inside a loop but get_ctrl() is member of an outer loop. This could happen, for example,
1837 // for Div nodes inside a loop (control input inside loop) without a use except for an UCT (outside the loop).
1838 // Rewire control of n to right outside of the loop, regardless if its input(s) are later sunk or not.
1839 _igvn.replace_input_of(n, 0, place_outside_loop(n_ctrl, loop_ctrl));
1840 }
1841 }
1842 if (n_loop != _ltree_root && n->outcnt() > 1) {
1843 // Compute early control: needed for anti-dependence analysis. It's also possible that as a result of
1844 // previous transformations in this loop opts round, the node can be hoisted now: early control will tell us.
1845 Node* early_ctrl = compute_early_ctrl(n, n_ctrl);
1846 if (n_loop->is_member(get_loop(early_ctrl)) && // check that this one can't be hoisted now
1847 ctrl_of_all_uses_out_of_loop(n, early_ctrl, n_loop)) { // All uses in outer loops!
1848 assert(!n->is_Store() && !n->is_LoadStore(), "no node with a side effect");
1849 Node* outer_loop_clone = nullptr;
1850 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin;) {
1851 Node* u = n->last_out(j); // Clone private computation per use
1852 _igvn.rehash_node_delayed(u);
1853 Node* x = n->clone(); // Clone computation
1854 Node* x_ctrl = nullptr;
1855 if (u->is_Phi()) {
1856 // Replace all uses of normal nodes. Replace Phi uses
1857 // individually, so the separate Nodes can sink down
1858 // different paths.
1859 uint k = 1;
1860 while (u->in(k) != n) k++;
1861 u->set_req(k, x);
1862 // x goes next to Phi input path
1863 x_ctrl = u->in(0)->in(k);
1864 // Find control for 'x' next to use but not inside inner loops.
1865 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1866 --j;
1867 } else { // Normal use
1868 if (has_ctrl(u)) {
1869 x_ctrl = get_ctrl(u);
1870 } else {
1871 x_ctrl = u->in(0);
1872 }
1873 // Find control for 'x' next to use but not inside inner loops.
1874 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1875 // Replace all uses
1876 if (u->is_ConstraintCast() && _igvn.type(n)->higher_equal(u->bottom_type()) && u->in(0) == x_ctrl) {
1877 // If we're sinking a chain of data nodes, we might have inserted a cast to pin the use which is not necessary
1878 // anymore now that we're going to pin n as well
1879 _igvn.replace_node(u, x);
1880 --j;
1881 } else {
1882 int nb = u->replace_edge(n, x, &_igvn);
1883 j -= nb;
1884 }
1885 }
1886
1887 if (n->is_Load()) {
1888 // For loads, add a control edge to a CFG node outside of the loop
1889 // to force them to not combine and return back inside the loop
1890 // during GVN optimization (4641526).
1891 assert(x_ctrl == get_late_ctrl_with_anti_dep(x->as_Load(), early_ctrl, x_ctrl), "anti-dependences were already checked");
1892
1893 IdealLoopTree* x_loop = get_loop(x_ctrl);
1894 Node* x_head = x_loop->_head;
1895 if (x_head->is_Loop() && x_head->is_OuterStripMinedLoop()) {
1896 // Do not add duplicate LoadNodes to the outer strip mined loop
1897 if (outer_loop_clone != nullptr) {
1898 _igvn.replace_node(x, outer_loop_clone);
1899 continue;
1900 }
1901 outer_loop_clone = x;
1902 }
1903 x->set_req(0, x_ctrl);
1904 } else if (n->in(0) != nullptr){
1905 x->set_req(0, x_ctrl);
1906 }
1907 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1908 assert(!n_loop->is_member(get_loop(x_ctrl)), "should have moved out of loop");
1909 register_new_node(x, x_ctrl);
1910
1911 // Chain of AddP nodes: (AddP base (AddP base (AddP base )))
1912 // All AddP nodes must keep the same base after sinking so:
1913 // 1- We don't add a CastPP here until the last one of the chain is sunk: if part of the chain is not sunk,
1914 // their bases remain the same.
1915 // (see 2- below)
1916 assert(!x->is_AddP() || !x->in(AddPNode::Address)->is_AddP() ||
1917 x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base) ||
1918 !x->in(AddPNode::Address)->in(AddPNode::Base)->eqv_uncast(x->in(AddPNode::Base)), "unexpected AddP shape");
1919 if (x->in(0) == nullptr && !x->is_DecodeNarrowPtr() &&
1920 !(x->is_AddP() && x->in(AddPNode::Address)->is_AddP() && x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base))) {
1921 assert(!x->is_Load(), "load should be pinned");
1922 // Use a cast node to pin clone out of loop
1923 Node* cast = nullptr;
1924 for (uint k = 0; k < x->req(); k++) {
1925 Node* in = x->in(k);
1926 if (in != nullptr && n_loop->is_member(get_loop(get_ctrl(in)))) {
1927 const Type* in_t = _igvn.type(in);
1928 cast = ConstraintCastNode::make_cast_for_type(x_ctrl, in, in_t,
1929 ConstraintCastNode::UnconditionalDependency, nullptr);
1930 }
1931 if (cast != nullptr) {
1932 Node* prev = _igvn.hash_find_insert(cast);
1933 if (prev != nullptr && get_ctrl(prev) == x_ctrl) {
1934 cast->destruct(&_igvn);
1935 cast = prev;
1936 } else {
1937 register_new_node(cast, x_ctrl);
1938 }
1939 x->replace_edge(in, cast);
1940 // Chain of AddP nodes:
1941 // 2- A CastPP of the base is only added now that all AddP nodes are sunk
1942 if (x->is_AddP() && k == AddPNode::Base) {
1943 update_addp_chain_base(x, n->in(AddPNode::Base), cast);
1944 }
1945 break;
1946 }
1947 }
1948 assert(cast != nullptr, "must have added a cast to pin the node");
1949 }
1950 }
1951 _igvn.remove_dead_node(n);
1952 }
1953 _dom_lca_tags_round = 0;
1954 }
1955 }
1956 }
1957
1958 void PhaseIdealLoop::update_addp_chain_base(Node* x, Node* old_base, Node* new_base) {
1959 ResourceMark rm;
1960 Node_List wq;
1961 wq.push(x);
1962 while (wq.size() != 0) {
1963 Node* n = wq.pop();
1964 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1965 Node* u = n->fast_out(i);
1966 if (u->is_AddP() && u->in(AddPNode::Base) == old_base) {
1967 _igvn.replace_input_of(u, AddPNode::Base, new_base);
1968 wq.push(u);
1969 }
1970 }
1971 }
1972 }
1973
1974 // Compute the early control of a node by following its inputs until we reach
1975 // nodes that are pinned. Then compute the LCA of the control of all pinned nodes.
1976 Node* PhaseIdealLoop::compute_early_ctrl(Node* n, Node* n_ctrl) {
1977 Node* early_ctrl = nullptr;
1978 ResourceMark rm;
1979 Unique_Node_List wq;
1980 wq.push(n);
1981 for (uint i = 0; i < wq.size(); i++) {
1982 Node* m = wq.at(i);
1983 Node* c = nullptr;
1984 if (m->is_CFG()) {
1985 c = m;
1986 } else if (m->pinned()) {
1987 c = m->in(0);
1988 } else {
1989 for (uint j = 0; j < m->req(); j++) {
1990 Node* in = m->in(j);
1991 if (in != nullptr) {
1992 wq.push(in);
1993 }
1994 }
1995 }
1996 if (c != nullptr) {
1997 assert(is_dominator(c, n_ctrl), "control input must dominate current control");
1998 if (early_ctrl == nullptr || is_dominator(early_ctrl, c)) {
1999 early_ctrl = c;
2000 }
2001 }
2002 }
2003 assert(is_dominator(early_ctrl, n_ctrl), "early control must dominate current control");
2004 return early_ctrl;
2005 }
2006
2007 bool PhaseIdealLoop::ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop) {
2008 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2009 Node* u = n->fast_out(i);
2010 if (u->is_Opaque1()) {
2011 return false; // Found loop limit, bugfix for 4677003
2012 }
2013 // We can't reuse tags in PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal() so make sure calls to
2014 // get_late_ctrl_with_anti_dep() use their own tag
2015 _dom_lca_tags_round++;
2016 assert(_dom_lca_tags_round != 0, "shouldn't wrap around");
2017
2018 if (u->is_Phi()) {
2019 for (uint j = 1; j < u->req(); ++j) {
2020 if (u->in(j) == n && !ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, u->in(0)->in(j))) {
2021 return false;
2022 }
2023 }
2024 } else {
2025 Node* ctrl = has_ctrl(u) ? get_ctrl(u) : u->in(0);
2026 if (!ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, ctrl)) {
2027 return false;
2028 }
2029 }
2030 }
2031 return true;
2032 }
2033
2034 bool PhaseIdealLoop::ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl) {
2035 if (n->is_Load()) {
2036 ctrl = get_late_ctrl_with_anti_dep(n->as_Load(), n_ctrl, ctrl);
2037 }
2038 IdealLoopTree *u_loop = get_loop(ctrl);
2039 if (u_loop == n_loop) {
2040 return false; // Found loop-varying use
2041 }
2042 if (n_loop->is_member(u_loop)) {
2043 return false; // Found use in inner loop
2044 }
2045 // Sinking a node from a pre loop to its main loop pins the node between the pre and main loops. If that node is input
2046 // to a check that's eliminated by range check elimination, it becomes input to an expression that feeds into the exit
2047 // test of the pre loop above the point in the graph where it's pinned.
2048 if (n_loop->_head->is_CountedLoop() && n_loop->_head->as_CountedLoop()->is_pre_loop() &&
2049 u_loop->_head->is_CountedLoop() && u_loop->_head->as_CountedLoop()->is_main_loop() &&
2050 n_loop->_next == get_loop(u_loop->_head->as_CountedLoop()->skip_strip_mined())) {
2051 return false;
2052 }
2053 return true;
2054 }
2055
2056 //------------------------------split_if_with_blocks---------------------------
2057 // Check for aggressive application of 'split-if' optimization,
2058 // using basic block level info.
2059 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) {
2060 Node* root = C->root();
2061 visited.set(root->_idx); // first, mark root as visited
2062 // Do pre-visit work for root
2063 Node* n = split_if_with_blocks_pre(root);
2064 uint cnt = n->outcnt();
2065 uint i = 0;
2066
2067 while (true) {
2068 // Visit all children
2069 if (i < cnt) {
2070 Node* use = n->raw_out(i);
2071 ++i;
2072 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
2073 // Now do pre-visit work for this use
2074 use = split_if_with_blocks_pre(use);
2075 nstack.push(n, i); // Save parent and next use's index.
2076 n = use; // Process all children of current use.
2077 cnt = use->outcnt();
2078 i = 0;
2079 }
2080 }
2081 else {
2082 // All of n's children have been processed, complete post-processing.
2083 if (cnt != 0 && !n->is_Con()) {
2084 assert(has_node(n), "no dead nodes");
2085 split_if_with_blocks_post(n);
2086 }
2087 if (must_throttle_split_if()) {
2088 nstack.clear();
2089 }
2090 if (nstack.is_empty()) {
2091 // Finished all nodes on stack.
2092 break;
2093 }
2094 // Get saved parent node and next use's index. Visit the rest of uses.
2095 n = nstack.node();
2096 cnt = n->outcnt();
2097 i = nstack.index();
2098 nstack.pop();
2099 }
2100 }
2101 }
2102
2103
2104 //=============================================================================
2105 //
2106 // C L O N E A L O O P B O D Y
2107 //
2108
2109 //------------------------------clone_iff--------------------------------------
2110 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2111 // "Nearly" because all Nodes have been cloned from the original in the loop,
2112 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2113 // through the Phi recursively, and return a Bool.
2114 Node* PhaseIdealLoop::clone_iff(PhiNode* phi) {
2115
2116 // Convert this Phi into a Phi merging Bools
2117 uint i;
2118 for (i = 1; i < phi->req(); i++) {
2119 Node *b = phi->in(i);
2120 if (b->is_Phi()) {
2121 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi()));
2122 } else {
2123 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
2124 }
2125 }
2126
2127 Node* n = phi->in(1);
2128 Node* sample_opaque = nullptr;
2129 Node *sample_bool = nullptr;
2130 if (n->Opcode() == Op_Opaque4) {
2131 sample_opaque = n;
2132 sample_bool = n->in(1);
2133 assert(sample_bool->is_Bool(), "wrong type");
2134 } else {
2135 sample_bool = n;
2136 }
2137 Node* sample_cmp = sample_bool->in(1);
2138 const Type* t = Type::TOP;
2139 const TypePtr* at = nullptr;
2140 if (sample_cmp->is_FlatArrayCheck()) {
2141 // Left input of a FlatArrayCheckNode is memory, set the (adr) type of the phi accordingly
2142 assert(sample_cmp->in(1)->bottom_type() == Type::MEMORY, "unexpected input type");
2143 t = Type::MEMORY;
2144 at = TypeRawPtr::BOTTOM;
2145 }
2146
2147 // Make Phis to merge the Cmp's inputs.
2148 PhiNode *phi1 = new PhiNode(phi->in(0), t, at);
2149 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
2150 for (i = 1; i < phi->req(); i++) {
2151 Node *n1 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
2152 Node *n2 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
2153 phi1->set_req(i, n1);
2154 phi2->set_req(i, n2);
2155 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2156 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2157 }
2158 // See if these Phis have been made before.
2159 // Register with optimizer
2160 Node *hit1 = _igvn.hash_find_insert(phi1);
2161 if (hit1) { // Hit, toss just made Phi
2162 _igvn.remove_dead_node(phi1); // Remove new phi
2163 assert(hit1->is_Phi(), "" );
2164 phi1 = (PhiNode*)hit1; // Use existing phi
2165 } else { // Miss
2166 _igvn.register_new_node_with_optimizer(phi1);
2167 }
2168 Node *hit2 = _igvn.hash_find_insert(phi2);
2169 if (hit2) { // Hit, toss just made Phi
2170 _igvn.remove_dead_node(phi2); // Remove new phi
2171 assert(hit2->is_Phi(), "" );
2172 phi2 = (PhiNode*)hit2; // Use existing phi
2173 } else { // Miss
2174 _igvn.register_new_node_with_optimizer(phi2);
2175 }
2176 // Register Phis with loop/block info
2177 set_ctrl(phi1, phi->in(0));
2178 set_ctrl(phi2, phi->in(0));
2179 // Make a new Cmp
2180 Node *cmp = sample_cmp->clone();
2181 cmp->set_req(1, phi1);
2182 cmp->set_req(2, phi2);
2183 _igvn.register_new_node_with_optimizer(cmp);
2184 set_ctrl(cmp, phi->in(0));
2185
2186 // Make a new Bool
2187 Node *b = sample_bool->clone();
2188 b->set_req(1,cmp);
2189 _igvn.register_new_node_with_optimizer(b);
2190 set_ctrl(b, phi->in(0));
2191
2192 if (sample_opaque != nullptr) {
2193 Node* opaque = sample_opaque->clone();
2194 opaque->set_req(1, b);
2195 _igvn.register_new_node_with_optimizer(opaque);
2196 set_ctrl(opaque, phi->in(0));
2197 return opaque;
2198 }
2199
2200 assert(b->is_Bool(), "");
2201 return b;
2202 }
2203
2204 //------------------------------clone_bool-------------------------------------
2205 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2206 // "Nearly" because all Nodes have been cloned from the original in the loop,
2207 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2208 // through the Phi recursively, and return a Bool.
2209 CmpNode*PhaseIdealLoop::clone_bool(PhiNode* phi) {
2210 uint i;
2211 // Convert this Phi into a Phi merging Bools
2212 for( i = 1; i < phi->req(); i++ ) {
2213 Node *b = phi->in(i);
2214 if( b->is_Phi() ) {
2215 _igvn.replace_input_of(phi, i, clone_bool(b->as_Phi()));
2216 } else {
2217 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
2218 }
2219 }
2220
2221 Node *sample_cmp = phi->in(1);
2222
2223 // Make Phis to merge the Cmp's inputs.
2224 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
2225 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
2226 for( uint j = 1; j < phi->req(); j++ ) {
2227 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
2228 Node *n1, *n2;
2229 if( cmp_top->is_Cmp() ) {
2230 n1 = cmp_top->in(1);
2231 n2 = cmp_top->in(2);
2232 } else {
2233 n1 = n2 = cmp_top;
2234 }
2235 phi1->set_req( j, n1 );
2236 phi2->set_req( j, n2 );
2237 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2238 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2239 }
2240
2241 // See if these Phis have been made before.
2242 // Register with optimizer
2243 Node *hit1 = _igvn.hash_find_insert(phi1);
2244 if( hit1 ) { // Hit, toss just made Phi
2245 _igvn.remove_dead_node(phi1); // Remove new phi
2246 assert( hit1->is_Phi(), "" );
2247 phi1 = (PhiNode*)hit1; // Use existing phi
2248 } else { // Miss
2249 _igvn.register_new_node_with_optimizer(phi1);
2250 }
2251 Node *hit2 = _igvn.hash_find_insert(phi2);
2252 if( hit2 ) { // Hit, toss just made Phi
2253 _igvn.remove_dead_node(phi2); // Remove new phi
2254 assert( hit2->is_Phi(), "" );
2255 phi2 = (PhiNode*)hit2; // Use existing phi
2256 } else { // Miss
2257 _igvn.register_new_node_with_optimizer(phi2);
2258 }
2259 // Register Phis with loop/block info
2260 set_ctrl(phi1, phi->in(0));
2261 set_ctrl(phi2, phi->in(0));
2262 // Make a new Cmp
2263 Node *cmp = sample_cmp->clone();
2264 cmp->set_req( 1, phi1 );
2265 cmp->set_req( 2, phi2 );
2266 _igvn.register_new_node_with_optimizer(cmp);
2267 set_ctrl(cmp, phi->in(0));
2268
2269 assert( cmp->is_Cmp(), "" );
2270 return (CmpNode*)cmp;
2271 }
2272
2273 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
2274 IdealLoopTree* loop, IdealLoopTree* outer_loop,
2275 Node_List*& split_if_set, Node_List*& split_bool_set,
2276 Node_List*& split_cex_set, Node_List& worklist,
2277 uint new_counter, CloneLoopMode mode) {
2278 Node* nnn = old_new[old->_idx];
2279 // Copy uses to a worklist, so I can munge the def-use info
2280 // with impunity.
2281 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2282 worklist.push(old->fast_out(j));
2283
2284 while( worklist.size() ) {
2285 Node *use = worklist.pop();
2286 if (!has_node(use)) continue; // Ignore dead nodes
2287 if (use->in(0) == C->top()) continue;
2288 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2289 // Check for data-use outside of loop - at least one of OLD or USE
2290 // must not be a CFG node.
2291 #ifdef ASSERT
2292 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == nullptr) {
2293 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
2294 assert(mode != IgnoreStripMined, "incorrect cloning mode");
2295 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node");
2296 }
2297 #endif
2298 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
2299
2300 // If the Data use is an IF, that means we have an IF outside of the
2301 // loop that is switching on a condition that is set inside of the
2302 // loop. Happens if people set a loop-exit flag; then test the flag
2303 // in the loop to break the loop, then test is again outside of the
2304 // loop to determine which way the loop exited.
2305 // Loop predicate If node connects to Bool node through Opaque1 node.
2306 //
2307 // If the use is an AllocateArray through its ValidLengthTest input,
2308 // make sure the Bool/Cmp input is cloned down to avoid a Phi between
2309 // the AllocateArray node and its ValidLengthTest input that could cause
2310 // split if to break.
2311 if (use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque4 ||
2312 (use->Opcode() == Op_AllocateArray && use->in(AllocateNode::ValidLengthTest) == old)) {
2313 // Since this code is highly unlikely, we lazily build the worklist
2314 // of such Nodes to go split.
2315 if (!split_if_set) {
2316 split_if_set = new Node_List();
2317 }
2318 split_if_set->push(use);
2319 }
2320 if (use->is_Bool()) {
2321 if (!split_bool_set) {
2322 split_bool_set = new Node_List();
2323 }
2324 split_bool_set->push(use);
2325 }
2326 if (use->Opcode() == Op_CreateEx) {
2327 if (!split_cex_set) {
2328 split_cex_set = new Node_List();
2329 }
2330 split_cex_set->push(use);
2331 }
2332
2333
2334 // Get "block" use is in
2335 uint idx = 0;
2336 while( use->in(idx) != old ) idx++;
2337 Node *prev = use->is_CFG() ? use : get_ctrl(use);
2338 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
2339 Node* cfg = (prev->_idx >= new_counter && prev->is_Region())
2340 ? prev->in(2)
2341 : idom(prev);
2342 if( use->is_Phi() ) // Phi use is in prior block
2343 cfg = prev->in(idx); // NOT in block of Phi itself
2344 if (cfg->is_top()) { // Use is dead?
2345 _igvn.replace_input_of(use, idx, C->top());
2346 continue;
2347 }
2348
2349 // If use is referenced through control edge... (idx == 0)
2350 if (mode == IgnoreStripMined && idx == 0) {
2351 LoopNode *head = loop->_head->as_Loop();
2352 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
2353 // That node is outside the inner loop, leave it outside the
2354 // outer loop as well to not confuse verification code.
2355 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
2356 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
2357 continue;
2358 }
2359 }
2360
2361 while(!outer_loop->is_member(get_loop(cfg))) {
2362 prev = cfg;
2363 cfg = (cfg->_idx >= new_counter && cfg->is_Region()) ? cfg->in(2) : idom(cfg);
2364 }
2365 // If the use occurs after merging several exits from the loop, then
2366 // old value must have dominated all those exits. Since the same old
2367 // value was used on all those exits we did not need a Phi at this
2368 // merge point. NOW we do need a Phi here. Each loop exit value
2369 // is now merged with the peeled body exit; each exit gets its own
2370 // private Phi and those Phis need to be merged here.
2371 Node *phi;
2372 if( prev->is_Region() ) {
2373 if( idx == 0 ) { // Updating control edge?
2374 phi = prev; // Just use existing control
2375 } else { // Else need a new Phi
2376 phi = PhiNode::make( prev, old );
2377 // Now recursively fix up the new uses of old!
2378 for( uint i = 1; i < prev->req(); i++ ) {
2379 worklist.push(phi); // Onto worklist once for each 'old' input
2380 }
2381 }
2382 } else {
2383 // Get new RegionNode merging old and new loop exits
2384 prev = old_new[prev->_idx];
2385 assert( prev, "just made this in step 7" );
2386 if( idx == 0) { // Updating control edge?
2387 phi = prev; // Just use existing control
2388 } else { // Else need a new Phi
2389 // Make a new Phi merging data values properly
2390 phi = PhiNode::make( prev, old );
2391 phi->set_req( 1, nnn );
2392 }
2393 }
2394 // If inserting a new Phi, check for prior hits
2395 if( idx != 0 ) {
2396 Node *hit = _igvn.hash_find_insert(phi);
2397 if( hit == nullptr ) {
2398 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2399 } else { // or
2400 // Remove the new phi from the graph and use the hit
2401 _igvn.remove_dead_node(phi);
2402 phi = hit; // Use existing phi
2403 }
2404 set_ctrl(phi, prev);
2405 }
2406 // Make 'use' use the Phi instead of the old loop body exit value
2407 assert(use->in(idx) == old, "old is still input of use");
2408 // We notify all uses of old, including use, and the indirect uses,
2409 // that may now be optimized because we have replaced old with phi.
2410 _igvn.add_users_to_worklist(old);
2411 _igvn.replace_input_of(use, idx, phi);
2412 if( use->_idx >= new_counter ) { // If updating new phis
2413 // Not needed for correctness, but prevents a weak assert
2414 // in AddPNode from tripping (when we end up with different
2415 // base & derived Phis that will become the same after
2416 // IGVN does CSE).
2417 Node *hit = _igvn.hash_find_insert(use);
2418 if( hit ) // Go ahead and re-hash for hits.
2419 _igvn.replace_node( use, hit );
2420 }
2421 }
2422 }
2423 }
2424
2425 static void collect_nodes_in_outer_loop_not_reachable_from_sfpt(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop,
2426 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase,
2427 bool check_old_new) {
2428 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2429 Node* u = n->fast_out(j);
2430 assert(check_old_new || old_new[u->_idx] == nullptr, "shouldn't have been cloned");
2431 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == nullptr)) {
2432 Node* c = phase->get_ctrl(u);
2433 IdealLoopTree* u_loop = phase->get_loop(c);
2434 assert(!loop->is_member(u_loop) || !loop->_body.contains(u), "can be in outer loop or out of both loops only");
2435 if (!loop->is_member(u_loop)) {
2436 if (outer_loop->is_member(u_loop)) {
2437 wq.push(u);
2438 } else {
2439 // nodes pinned with control in the outer loop but not referenced from the safepoint must be moved out of
2440 // the outer loop too
2441 Node* u_c = u->in(0);
2442 if (u_c != nullptr) {
2443 IdealLoopTree* u_c_loop = phase->get_loop(u_c);
2444 if (outer_loop->is_member(u_c_loop) && !loop->is_member(u_c_loop)) {
2445 wq.push(u);
2446 }
2447 }
2448 }
2449 }
2450 }
2451 }
2452 }
2453
2454 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2455 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2456 Node_List& extra_data_nodes) {
2457 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2458 CountedLoopNode* cl = head->as_CountedLoop();
2459 Node* l = cl->outer_loop();
2460 Node* tail = cl->outer_loop_tail();
2461 IfNode* le = cl->outer_loop_end();
2462 Node* sfpt = cl->outer_safepoint();
2463 CountedLoopEndNode* cle = cl->loopexit();
2464 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2465 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2466 Node* cle_out = cle->proj_out(false);
2467
2468 Node* new_sfpt = nullptr;
2469 Node* new_cle_out = cle_out->clone();
2470 old_new.map(cle_out->_idx, new_cle_out);
2471 if (mode == CloneIncludesStripMined) {
2472 // clone outer loop body
2473 Node* new_l = l->clone();
2474 Node* new_tail = tail->clone();
2475 IfNode* new_le = le->clone()->as_If();
2476 new_sfpt = sfpt->clone();
2477
2478 set_loop(new_l, outer_loop->_parent);
2479 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2480 set_loop(new_cle_out, outer_loop->_parent);
2481 set_idom(new_cle_out, new_cle, dd);
2482 set_loop(new_sfpt, outer_loop->_parent);
2483 set_idom(new_sfpt, new_cle_out, dd);
2484 set_loop(new_le, outer_loop->_parent);
2485 set_idom(new_le, new_sfpt, dd);
2486 set_loop(new_tail, outer_loop->_parent);
2487 set_idom(new_tail, new_le, dd);
2488 set_idom(new_cl, new_l, dd);
2489
2490 old_new.map(l->_idx, new_l);
2491 old_new.map(tail->_idx, new_tail);
2492 old_new.map(le->_idx, new_le);
2493 old_new.map(sfpt->_idx, new_sfpt);
2494
2495 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2496 new_l->set_req(0, new_l);
2497 new_tail->set_req(0, new_le);
2498 new_le->set_req(0, new_sfpt);
2499 new_sfpt->set_req(0, new_cle_out);
2500 new_cle_out->set_req(0, new_cle);
2501 new_cl->set_req(LoopNode::EntryControl, new_l);
2502
2503 _igvn.register_new_node_with_optimizer(new_l);
2504 _igvn.register_new_node_with_optimizer(new_tail);
2505 _igvn.register_new_node_with_optimizer(new_le);
2506 } else {
2507 Node *newhead = old_new[loop->_head->_idx];
2508 newhead->as_Loop()->clear_strip_mined();
2509 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2510 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2511 }
2512 // Look at data node that were assigned a control in the outer
2513 // loop: they are kept in the outer loop by the safepoint so start
2514 // from the safepoint node's inputs.
2515 IdealLoopTree* outer_loop = get_loop(l);
2516 Node_Stack stack(2);
2517 stack.push(sfpt, 1);
2518 uint new_counter = C->unique();
2519 while (stack.size() > 0) {
2520 Node* n = stack.node();
2521 uint i = stack.index();
2522 while (i < n->req() &&
2523 (n->in(i) == nullptr ||
2524 !has_ctrl(n->in(i)) ||
2525 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2526 (old_new[n->in(i)->_idx] != nullptr && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2527 i++;
2528 }
2529 if (i < n->req()) {
2530 stack.set_index(i+1);
2531 stack.push(n->in(i), 0);
2532 } else {
2533 assert(old_new[n->_idx] == nullptr || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2534 Node* m = n == sfpt ? new_sfpt : n->clone();
2535 if (m != nullptr) {
2536 for (uint i = 0; i < n->req(); i++) {
2537 if (m->in(i) != nullptr && old_new[m->in(i)->_idx] != nullptr) {
2538 m->set_req(i, old_new[m->in(i)->_idx]);
2539 }
2540 }
2541 } else {
2542 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2543 }
2544 if (n != sfpt) {
2545 extra_data_nodes.push(n);
2546 _igvn.register_new_node_with_optimizer(m);
2547 assert(get_ctrl(n) == cle_out, "what other control?");
2548 set_ctrl(m, new_cle_out);
2549 old_new.map(n->_idx, m);
2550 }
2551 stack.pop();
2552 }
2553 }
2554 if (mode == CloneIncludesStripMined) {
2555 _igvn.register_new_node_with_optimizer(new_sfpt);
2556 _igvn.register_new_node_with_optimizer(new_cle_out);
2557 }
2558 // Some other transformation may have pessimistically assigned some
2559 // data nodes to the outer loop. Set their control so they are out
2560 // of the outer loop.
2561 ResourceMark rm;
2562 Unique_Node_List wq;
2563 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2564 Node* old = extra_data_nodes.at(i);
2565 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2566 }
2567
2568 for (uint i = 0; i < loop->_body.size(); i++) {
2569 Node* old = loop->_body.at(i);
2570 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2571 }
2572
2573 Node* inner_out = sfpt->in(0);
2574 if (inner_out->outcnt() > 1) {
2575 collect_nodes_in_outer_loop_not_reachable_from_sfpt(inner_out, loop, outer_loop, old_new, wq, this, true);
2576 }
2577
2578 Node* new_ctrl = cl->outer_loop_exit();
2579 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest");
2580 for (uint i = 0; i < wq.size(); i++) {
2581 Node* n = wq.at(i);
2582 set_ctrl(n, new_ctrl);
2583 if (n->in(0) != nullptr) {
2584 _igvn.replace_input_of(n, 0, new_ctrl);
2585 }
2586 collect_nodes_in_outer_loop_not_reachable_from_sfpt(n, loop, outer_loop, old_new, wq, this, false);
2587 }
2588 } else {
2589 Node *newhead = old_new[loop->_head->_idx];
2590 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2591 }
2592 }
2593
2594 //------------------------------clone_loop-------------------------------------
2595 //
2596 // C L O N E A L O O P B O D Y
2597 //
2598 // This is the basic building block of the loop optimizations. It clones an
2599 // entire loop body. It makes an old_new loop body mapping; with this mapping
2600 // you can find the new-loop equivalent to an old-loop node. All new-loop
2601 // nodes are exactly equal to their old-loop counterparts, all edges are the
2602 // same. All exits from the old-loop now have a RegionNode that merges the
2603 // equivalent new-loop path. This is true even for the normal "loop-exit"
2604 // condition. All uses of loop-invariant old-loop values now come from (one
2605 // or more) Phis that merge their new-loop equivalents.
2606 //
2607 // This operation leaves the graph in an illegal state: there are two valid
2608 // control edges coming from the loop pre-header to both loop bodies. I'll
2609 // definitely have to hack the graph after running this transform.
2610 //
2611 // From this building block I will further edit edges to perform loop peeling
2612 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2613 //
2614 // Parameter side_by_size_idom:
2615 // When side_by_size_idom is null, the dominator tree is constructed for
2616 // the clone loop to dominate the original. Used in construction of
2617 // pre-main-post loop sequence.
2618 // When nonnull, the clone and original are side-by-side, both are
2619 // dominated by the side_by_side_idom node. Used in construction of
2620 // unswitched loops.
2621 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2622 CloneLoopMode mode, Node* side_by_side_idom) {
2623
2624 LoopNode* head = loop->_head->as_Loop();
2625 head->verify_strip_mined(1);
2626
2627 if (C->do_vector_loop() && PrintOpto) {
2628 const char* mname = C->method()->name()->as_quoted_ascii();
2629 if (mname != nullptr) {
2630 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2631 }
2632 }
2633
2634 CloneMap& cm = C->clone_map();
2635 if (C->do_vector_loop()) {
2636 cm.set_clone_idx(cm.max_gen()+1);
2637 #ifndef PRODUCT
2638 if (PrintOpto) {
2639 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2640 loop->dump_head();
2641 }
2642 #endif
2643 }
2644
2645 // Step 1: Clone the loop body. Make the old->new mapping.
2646 clone_loop_body(loop->_body, old_new, &cm);
2647
2648 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2649
2650 // Step 2: Fix the edges in the new body. If the old input is outside the
2651 // loop use it. If the old input is INside the loop, use the corresponding
2652 // new node instead.
2653 fix_body_edges(loop->_body, loop, old_new, dd, outer_loop->_parent, false);
2654
2655 Node_List extra_data_nodes; // data nodes in the outer strip mined loop
2656 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2657
2658 // Step 3: Now fix control uses. Loop varying control uses have already
2659 // been fixed up (as part of all input edges in Step 2). Loop invariant
2660 // control uses must be either an IfFalse or an IfTrue. Make a merge
2661 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2662 // refer to this.
2663 Node_List worklist;
2664 uint new_counter = C->unique();
2665 fix_ctrl_uses(loop->_body, loop, old_new, mode, side_by_side_idom, &cm, worklist);
2666
2667 // Step 4: If loop-invariant use is not control, it must be dominated by a
2668 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2669 // there if needed. Make a Phi there merging old and new used values.
2670 Node_List *split_if_set = nullptr;
2671 Node_List *split_bool_set = nullptr;
2672 Node_List *split_cex_set = nullptr;
2673 fix_data_uses(loop->_body, loop, mode, outer_loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
2674
2675 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2676 Node* old = extra_data_nodes.at(i);
2677 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2678 split_bool_set, split_cex_set, worklist, new_counter,
2679 mode);
2680 }
2681
2682 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2683 // the loop uses a condition set in the loop. The original IF probably
2684 // takes control from one or more OLD Regions (which in turn get from NEW
2685 // Regions). In any case, there will be a set of Phis for each merge point
2686 // from the IF up to where the original BOOL def exists the loop.
2687 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
2688
2689 }
2690
2691 void PhaseIdealLoop::finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set) {
2692 if (split_if_set) {
2693 while (split_if_set->size()) {
2694 Node *iff = split_if_set->pop();
2695 uint input = iff->Opcode() == Op_AllocateArray ? AllocateNode::ValidLengthTest : 1;
2696 if (iff->in(input)->is_Phi()) {
2697 Node *b = clone_iff(iff->in(input)->as_Phi());
2698 _igvn.replace_input_of(iff, input, b);
2699 }
2700 }
2701 }
2702 if (split_bool_set) {
2703 while (split_bool_set->size()) {
2704 Node *b = split_bool_set->pop();
2705 Node *phi = b->in(1);
2706 assert(phi->is_Phi(), "");
2707 CmpNode *cmp = clone_bool((PhiNode*) phi);
2708 _igvn.replace_input_of(b, 1, cmp);
2709 }
2710 }
2711 if (split_cex_set) {
2712 while (split_cex_set->size()) {
2713 Node *b = split_cex_set->pop();
2714 assert(b->in(0)->is_Region(), "");
2715 assert(b->in(1)->is_Phi(), "");
2716 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2717 split_up(b, b->in(0), nullptr);
2718 }
2719 }
2720 }
2721
2722 void PhaseIdealLoop::fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop,
2723 uint new_counter, Node_List &old_new, Node_List &worklist, Node_List*& split_if_set,
2724 Node_List*& split_bool_set, Node_List*& split_cex_set) {
2725 for(uint i = 0; i < body.size(); i++ ) {
2726 Node* old = body.at(i);
2727 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2728 split_bool_set, split_cex_set, worklist, new_counter,
2729 mode);
2730 }
2731 }
2732
2733 void PhaseIdealLoop::fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode,
2734 Node* side_by_side_idom, CloneMap* cm, Node_List &worklist) {
2735 LoopNode* head = loop->_head->as_Loop();
2736 for(uint i = 0; i < body.size(); i++ ) {
2737 Node* old = body.at(i);
2738 if( !old->is_CFG() ) continue;
2739
2740 // Copy uses to a worklist, so I can munge the def-use info
2741 // with impunity.
2742 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) {
2743 worklist.push(old->fast_out(j));
2744 }
2745
2746 while (worklist.size()) { // Visit all uses
2747 Node *use = worklist.pop();
2748 if (!has_node(use)) continue; // Ignore dead nodes
2749 IdealLoopTree *use_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use );
2750 if (!loop->is_member(use_loop) && use->is_CFG()) {
2751 // Both OLD and USE are CFG nodes here.
2752 assert(use->is_Proj(), "" );
2753 Node* nnn = old_new[old->_idx];
2754
2755 Node* newuse = nullptr;
2756 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2757 CountedLoopNode* cl = head->as_CountedLoop();
2758 CountedLoopEndNode* cle = cl->loopexit();
2759 Node* cle_out = cle->proj_out_or_null(false);
2760 if (use == cle_out) {
2761 IfNode* le = cl->outer_loop_end();
2762 use = le->proj_out(false);
2763 use_loop = get_loop(use);
2764 if (mode == CloneIncludesStripMined) {
2765 nnn = old_new[le->_idx];
2766 } else {
2767 newuse = old_new[cle_out->_idx];
2768 }
2769 }
2770 }
2771 if (newuse == nullptr) {
2772 newuse = use->clone();
2773 }
2774
2775 // Clone the loop exit control projection
2776 if (C->do_vector_loop() && cm != nullptr) {
2777 cm->verify_insert_and_clone(use, newuse, cm->clone_idx());
2778 }
2779 newuse->set_req(0,nnn);
2780 _igvn.register_new_node_with_optimizer(newuse);
2781 set_loop(newuse, use_loop);
2782 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2783
2784 // We need a Region to merge the exit from the peeled body and the
2785 // exit from the old loop body.
2786 RegionNode *r = new RegionNode(3);
2787 uint dd_r = MIN2(dom_depth(newuse), dom_depth(use));
2788 assert(dd_r >= dom_depth(dom_lca(newuse, use)), "" );
2789
2790 // The original user of 'use' uses 'r' instead.
2791 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2792 Node* useuse = use->last_out(l);
2793 _igvn.rehash_node_delayed(useuse);
2794 uint uses_found = 0;
2795 if (useuse->in(0) == use) {
2796 useuse->set_req(0, r);
2797 uses_found++;
2798 if (useuse->is_CFG()) {
2799 // This is not a dom_depth > dd_r because when new
2800 // control flow is constructed by a loop opt, a node and
2801 // its dominator can end up at the same dom_depth
2802 assert(dom_depth(useuse) >= dd_r, "");
2803 set_idom(useuse, r, dom_depth(useuse));
2804 }
2805 }
2806 for (uint k = 1; k < useuse->req(); k++) {
2807 if( useuse->in(k) == use ) {
2808 useuse->set_req(k, r);
2809 uses_found++;
2810 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2811 // This is not a dom_depth > dd_r because when new
2812 // control flow is constructed by a loop opt, a node
2813 // and its dominator can end up at the same dom_depth
2814 assert(dom_depth(useuse) >= dd_r , "");
2815 set_idom(useuse, r, dom_depth(useuse));
2816 }
2817 }
2818 }
2819 l -= uses_found; // we deleted 1 or more copies of this edge
2820 }
2821
2822 assert(use->is_Proj(), "loop exit should be projection");
2823 // lazy_replace() below moves all nodes that are:
2824 // - control dependent on the loop exit or
2825 // - have control set to the loop exit
2826 // below the post-loop merge point. lazy_replace() takes a dead control as first input. To make it
2827 // possible to use it, the loop exit projection is cloned and becomes the new exit projection. The initial one
2828 // becomes dead and is "replaced" by the region.
2829 Node* use_clone = use->clone();
2830 register_control(use_clone, use_loop, idom(use), dom_depth(use));
2831 // Now finish up 'r'
2832 r->set_req(1, newuse);
2833 r->set_req(2, use_clone);
2834 _igvn.register_new_node_with_optimizer(r);
2835 set_loop(r, use_loop);
2836 set_idom(r, (side_by_side_idom == nullptr) ? newuse->in(0) : side_by_side_idom, dd_r);
2837 lazy_replace(use, r);
2838 // Map the (cloned) old use to the new merge point
2839 old_new.map(use_clone->_idx, r);
2840 } // End of if a loop-exit test
2841 }
2842 }
2843 }
2844
2845 void PhaseIdealLoop::fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd,
2846 IdealLoopTree* parent, bool partial) {
2847 for(uint i = 0; i < body.size(); i++ ) {
2848 Node *old = body.at(i);
2849 Node *nnn = old_new[old->_idx];
2850 // Fix CFG/Loop controlling the new node
2851 if (has_ctrl(old)) {
2852 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2853 } else {
2854 set_loop(nnn, parent);
2855 if (old->outcnt() > 0) {
2856 Node* dom = idom(old);
2857 if (old_new[dom->_idx] != nullptr) {
2858 dom = old_new[dom->_idx];
2859 set_idom(nnn, dom, dd );
2860 }
2861 }
2862 }
2863 // Correct edges to the new node
2864 for (uint j = 0; j < nnn->req(); j++) {
2865 Node *n = nnn->in(j);
2866 if (n != nullptr) {
2867 IdealLoopTree *old_in_loop = get_loop(has_ctrl(n) ? get_ctrl(n) : n);
2868 if (loop->is_member(old_in_loop)) {
2869 if (old_new[n->_idx] != nullptr) {
2870 nnn->set_req(j, old_new[n->_idx]);
2871 } else {
2872 assert(!body.contains(n), "");
2873 assert(partial, "node not cloned");
2874 }
2875 }
2876 }
2877 }
2878 _igvn.hash_find_insert(nnn);
2879 }
2880 }
2881
2882 void PhaseIdealLoop::clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm) {
2883 for (uint i = 0; i < body.size(); i++) {
2884 Node* old = body.at(i);
2885 Node* nnn = old->clone();
2886 old_new.map(old->_idx, nnn);
2887 if (C->do_vector_loop() && cm != nullptr) {
2888 cm->verify_insert_and_clone(old, nnn, cm->clone_idx());
2889 }
2890 _igvn.register_new_node_with_optimizer(nnn);
2891 }
2892 }
2893
2894
2895 //---------------------- stride_of_possible_iv -------------------------------------
2896 // Looks for an iff/bool/comp with one operand of the compare
2897 // being a cycle involving an add and a phi,
2898 // with an optional truncation (left-shift followed by a right-shift)
2899 // of the add. Returns zero if not an iv.
2900 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2901 Node* trunc1 = nullptr;
2902 Node* trunc2 = nullptr;
2903 const TypeInteger* ttype = nullptr;
2904 if (!iff->is_If() || iff->in(1) == nullptr || !iff->in(1)->is_Bool()) {
2905 return 0;
2906 }
2907 BoolNode* bl = iff->in(1)->as_Bool();
2908 Node* cmp = bl->in(1);
2909 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2910 return 0;
2911 }
2912 // Must have an invariant operand
2913 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2914 return 0;
2915 }
2916 Node* add2 = nullptr;
2917 Node* cmp1 = cmp->in(1);
2918 if (cmp1->is_Phi()) {
2919 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2920 Node* phi = cmp1;
2921 for (uint i = 1; i < phi->req(); i++) {
2922 Node* in = phi->in(i);
2923 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2924 &trunc1, &trunc2, &ttype, T_INT);
2925 if (add && add->in(1) == phi) {
2926 add2 = add->in(2);
2927 break;
2928 }
2929 }
2930 } else {
2931 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2932 Node* addtrunc = cmp1;
2933 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2934 &trunc1, &trunc2, &ttype, T_INT);
2935 if (add && add->in(1)->is_Phi()) {
2936 Node* phi = add->in(1);
2937 for (uint i = 1; i < phi->req(); i++) {
2938 if (phi->in(i) == addtrunc) {
2939 add2 = add->in(2);
2940 break;
2941 }
2942 }
2943 }
2944 }
2945 if (add2 != nullptr) {
2946 const TypeInt* add2t = _igvn.type(add2)->is_int();
2947 if (add2t->is_con()) {
2948 return add2t->get_con();
2949 }
2950 }
2951 return 0;
2952 }
2953
2954
2955 //---------------------- stay_in_loop -------------------------------------
2956 // Return the (unique) control output node that's in the loop (if it exists.)
2957 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2958 Node* unique = nullptr;
2959 if (!n) return nullptr;
2960 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2961 Node* use = n->fast_out(i);
2962 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2963 if (unique != nullptr) {
2964 return nullptr;
2965 }
2966 unique = use;
2967 }
2968 }
2969 return unique;
2970 }
2971
2972 //------------------------------ register_node -------------------------------------
2973 // Utility to register node "n" with PhaseIdealLoop
2974 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree* loop, Node* pred, uint ddepth) {
2975 _igvn.register_new_node_with_optimizer(n);
2976 loop->_body.push(n);
2977 if (n->is_CFG()) {
2978 set_loop(n, loop);
2979 set_idom(n, pred, ddepth);
2980 } else {
2981 set_ctrl(n, pred);
2982 }
2983 }
2984
2985 //------------------------------ proj_clone -------------------------------------
2986 // Utility to create an if-projection
2987 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2988 ProjNode* c = p->clone()->as_Proj();
2989 c->set_req(0, iff);
2990 return c;
2991 }
2992
2993 //------------------------------ short_circuit_if -------------------------------------
2994 // Force the iff control output to be the live_proj
2995 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2996 guarantee(live_proj != nullptr, "null projection");
2997 int proj_con = live_proj->_con;
2998 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2999 Node *con = _igvn.intcon(proj_con);
3000 set_ctrl(con, C->root());
3001 if (iff) {
3002 iff->set_req(1, con);
3003 }
3004 return con;
3005 }
3006
3007 //------------------------------ insert_if_before_proj -------------------------------------
3008 // Insert a new if before an if projection (* - new node)
3009 //
3010 // before
3011 // if(test)
3012 // / \
3013 // v v
3014 // other-proj proj (arg)
3015 //
3016 // after
3017 // if(test)
3018 // / \
3019 // / v
3020 // | * proj-clone
3021 // v |
3022 // other-proj v
3023 // * new_if(relop(cmp[IU](left,right)))
3024 // / \
3025 // v v
3026 // * new-proj proj
3027 // (returned)
3028 //
3029 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
3030 IfNode* iff = proj->in(0)->as_If();
3031 IdealLoopTree *loop = get_loop(proj);
3032 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
3033 uint ddepth = dom_depth(proj);
3034
3035 _igvn.rehash_node_delayed(iff);
3036 _igvn.rehash_node_delayed(proj);
3037
3038 proj->set_req(0, nullptr); // temporary disconnect
3039 ProjNode* proj2 = proj_clone(proj, iff);
3040 register_node(proj2, loop, iff, ddepth);
3041
3042 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
3043 register_node(cmp, loop, proj2, ddepth);
3044
3045 BoolNode* bol = new BoolNode(cmp, relop);
3046 register_node(bol, loop, proj2, ddepth);
3047
3048 int opcode = iff->Opcode();
3049 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
3050 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
3051 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
3052 register_node(new_if, loop, proj2, ddepth);
3053
3054 proj->set_req(0, new_if); // reattach
3055 set_idom(proj, new_if, ddepth);
3056
3057 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
3058 guarantee(new_exit != nullptr, "null exit node");
3059 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
3060
3061 return new_exit;
3062 }
3063
3064 //------------------------------ insert_region_before_proj -------------------------------------
3065 // Insert a region before an if projection (* - new node)
3066 //
3067 // before
3068 // if(test)
3069 // / |
3070 // v |
3071 // proj v
3072 // other-proj
3073 //
3074 // after
3075 // if(test)
3076 // / |
3077 // v |
3078 // * proj-clone v
3079 // | other-proj
3080 // v
3081 // * new-region
3082 // |
3083 // v
3084 // * dum_if
3085 // / \
3086 // v \
3087 // * dum-proj v
3088 // proj
3089 //
3090 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
3091 IfNode* iff = proj->in(0)->as_If();
3092 IdealLoopTree *loop = get_loop(proj);
3093 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
3094 uint ddepth = dom_depth(proj);
3095
3096 _igvn.rehash_node_delayed(iff);
3097 _igvn.rehash_node_delayed(proj);
3098
3099 proj->set_req(0, nullptr); // temporary disconnect
3100 ProjNode* proj2 = proj_clone(proj, iff);
3101 register_node(proj2, loop, iff, ddepth);
3102
3103 RegionNode* reg = new RegionNode(2);
3104 reg->set_req(1, proj2);
3105 register_node(reg, loop, iff, ddepth);
3106
3107 IfNode* dum_if = new IfNode(reg, short_circuit_if(nullptr, proj), iff->_prob, iff->_fcnt);
3108 register_node(dum_if, loop, reg, ddepth);
3109
3110 proj->set_req(0, dum_if); // reattach
3111 set_idom(proj, dum_if, ddepth);
3112
3113 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
3114 register_node(dum_proj, loop, dum_if, ddepth);
3115
3116 return reg;
3117 }
3118
3119 //------------------------------ insert_cmpi_loop_exit -------------------------------------
3120 // Clone a signed compare loop exit from an unsigned compare and
3121 // insert it before the unsigned cmp on the stay-in-loop path.
3122 // All new nodes inserted in the dominator tree between the original
3123 // if and it's projections. The original if test is replaced with
3124 // a constant to force the stay-in-loop path.
3125 //
3126 // This is done to make sure that the original if and it's projections
3127 // still dominate the same set of control nodes, that the ctrl() relation
3128 // from data nodes to them is preserved, and that their loop nesting is
3129 // preserved.
3130 //
3131 // before
3132 // if(i <u limit) unsigned compare loop exit
3133 // / |
3134 // v v
3135 // exit-proj stay-in-loop-proj
3136 //
3137 // after
3138 // if(stay-in-loop-const) original if
3139 // / |
3140 // / v
3141 // / if(i < limit) new signed test
3142 // / / |
3143 // / / v
3144 // / / if(i <u limit) new cloned unsigned test
3145 // / / / |
3146 // v v v |
3147 // region |
3148 // | |
3149 // dum-if |
3150 // / | |
3151 // ether | |
3152 // v v
3153 // exit-proj stay-in-loop-proj
3154 //
3155 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
3156 const bool Signed = true;
3157 const bool Unsigned = false;
3158
3159 BoolNode* bol = if_cmpu->in(1)->as_Bool();
3160 if (bol->_test._test != BoolTest::lt) return nullptr;
3161 CmpNode* cmpu = bol->in(1)->as_Cmp();
3162 if (cmpu->Opcode() != Op_CmpU) return nullptr;
3163 int stride = stride_of_possible_iv(if_cmpu);
3164 if (stride == 0) return nullptr;
3165
3166 Node* lp_proj = stay_in_loop(if_cmpu, loop);
3167 guarantee(lp_proj != nullptr, "null loop node");
3168
3169 ProjNode* lp_continue = lp_proj->as_Proj();
3170 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
3171 if (!lp_exit->is_IfFalse()) {
3172 // The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit).
3173 // We therefore can't add a single exit condition.
3174 return nullptr;
3175 }
3176 // The loop exit condition is !(i <u limit) ==> (i < 0 || i >= limit).
3177 // Split out the exit condition (i < 0) for stride < 0 or (i >= limit) for stride > 0.
3178 Node* limit = nullptr;
3179 if (stride > 0) {
3180 limit = cmpu->in(2);
3181 } else {
3182 limit = _igvn.makecon(TypeInt::ZERO);
3183 set_ctrl(limit, C->root());
3184 }
3185 // Create a new region on the exit path
3186 RegionNode* reg = insert_region_before_proj(lp_exit);
3187 guarantee(reg != nullptr, "null region node");
3188
3189 // Clone the if-cmpu-true-false using a signed compare
3190 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
3191 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
3192 reg->add_req(cmpi_exit);
3193
3194 // Clone the if-cmpu-true-false
3195 BoolTest::mask rel_u = bol->_test._test;
3196 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
3197 reg->add_req(cmpu_exit);
3198
3199 // Force original if to stay in loop.
3200 short_circuit_if(if_cmpu, lp_continue);
3201
3202 return cmpi_exit->in(0)->as_If();
3203 }
3204
3205 //------------------------------ remove_cmpi_loop_exit -------------------------------------
3206 // Remove a previously inserted signed compare loop exit.
3207 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
3208 Node* lp_proj = stay_in_loop(if_cmp, loop);
3209 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
3210 stay_in_loop(lp_proj, loop)->is_If() &&
3211 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
3212 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
3213 set_ctrl(con, C->root());
3214 if_cmp->set_req(1, con);
3215 }
3216
3217 //------------------------------ scheduled_nodelist -------------------------------------
3218 // Create a post order schedule of nodes that are in the
3219 // "member" set. The list is returned in "sched".
3220 // The first node in "sched" is the loop head, followed by
3221 // nodes which have no inputs in the "member" set, and then
3222 // followed by the nodes that have an immediate input dependence
3223 // on a node in "sched".
3224 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
3225
3226 assert(member.test(loop->_head->_idx), "loop head must be in member set");
3227 VectorSet visited;
3228 Node_Stack nstack(loop->_body.size());
3229
3230 Node* n = loop->_head; // top of stack is cached in "n"
3231 uint idx = 0;
3232 visited.set(n->_idx);
3233
3234 // Initially push all with no inputs from within member set
3235 for(uint i = 0; i < loop->_body.size(); i++ ) {
3236 Node *elt = loop->_body.at(i);
3237 if (member.test(elt->_idx)) {
3238 bool found = false;
3239 for (uint j = 0; j < elt->req(); j++) {
3240 Node* def = elt->in(j);
3241 if (def && member.test(def->_idx) && def != elt) {
3242 found = true;
3243 break;
3244 }
3245 }
3246 if (!found && elt != loop->_head) {
3247 nstack.push(n, idx);
3248 n = elt;
3249 assert(!visited.test(n->_idx), "not seen yet");
3250 visited.set(n->_idx);
3251 }
3252 }
3253 }
3254
3255 // traverse out's that are in the member set
3256 while (true) {
3257 if (idx < n->outcnt()) {
3258 Node* use = n->raw_out(idx);
3259 idx++;
3260 if (!visited.test_set(use->_idx)) {
3261 if (member.test(use->_idx)) {
3262 nstack.push(n, idx);
3263 n = use;
3264 idx = 0;
3265 }
3266 }
3267 } else {
3268 // All outputs processed
3269 sched.push(n);
3270 if (nstack.is_empty()) break;
3271 n = nstack.node();
3272 idx = nstack.index();
3273 nstack.pop();
3274 }
3275 }
3276 }
3277
3278
3279 //------------------------------ has_use_in_set -------------------------------------
3280 // Has a use in the vector set
3281 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
3282 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3283 Node* use = n->fast_out(j);
3284 if (vset.test(use->_idx)) {
3285 return true;
3286 }
3287 }
3288 return false;
3289 }
3290
3291
3292 //------------------------------ has_use_internal_to_set -------------------------------------
3293 // Has use internal to the vector set (ie. not in a phi at the loop head)
3294 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
3295 Node* head = loop->_head;
3296 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3297 Node* use = n->fast_out(j);
3298 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
3299 return true;
3300 }
3301 }
3302 return false;
3303 }
3304
3305
3306 //------------------------------ clone_for_use_outside_loop -------------------------------------
3307 // clone "n" for uses that are outside of loop
3308 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
3309 int cloned = 0;
3310 assert(worklist.size() == 0, "should be empty");
3311 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3312 Node* use = n->fast_out(j);
3313 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
3314 worklist.push(use);
3315 }
3316 }
3317
3318 if (C->check_node_count(worklist.size() + NodeLimitFudgeFactor,
3319 "Too many clones required in clone_for_use_outside_loop in partial peeling")) {
3320 return -1;
3321 }
3322
3323 while( worklist.size() ) {
3324 Node *use = worklist.pop();
3325 if (!has_node(use) || use->in(0) == C->top()) continue;
3326 uint j;
3327 for (j = 0; j < use->req(); j++) {
3328 if (use->in(j) == n) break;
3329 }
3330 assert(j < use->req(), "must be there");
3331
3332 // clone "n" and insert it between the inputs of "n" and the use outside the loop
3333 Node* n_clone = n->clone();
3334 _igvn.replace_input_of(use, j, n_clone);
3335 cloned++;
3336 Node* use_c;
3337 if (!use->is_Phi()) {
3338 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
3339 } else {
3340 // Use in a phi is considered a use in the associated predecessor block
3341 use_c = use->in(0)->in(j);
3342 }
3343 set_ctrl(n_clone, use_c);
3344 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
3345 get_loop(use_c)->_body.push(n_clone);
3346 _igvn.register_new_node_with_optimizer(n_clone);
3347 #ifndef PRODUCT
3348 if (TracePartialPeeling) {
3349 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
3350 }
3351 #endif
3352 }
3353 return cloned;
3354 }
3355
3356
3357 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
3358 // clone "n" for special uses that are in the not_peeled region.
3359 // If these def-uses occur in separate blocks, the code generator
3360 // marks the method as not compilable. For example, if a "BoolNode"
3361 // is in a different basic block than the "IfNode" that uses it, then
3362 // the compilation is aborted in the code generator.
3363 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
3364 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
3365 if (n->is_Phi() || n->is_Load()) {
3366 return;
3367 }
3368 assert(worklist.size() == 0, "should be empty");
3369 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3370 Node* use = n->fast_out(j);
3371 if ( not_peel.test(use->_idx) &&
3372 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
3373 use->in(1) == n) {
3374 worklist.push(use);
3375 }
3376 }
3377 if (worklist.size() > 0) {
3378 // clone "n" and insert it between inputs of "n" and the use
3379 Node* n_clone = n->clone();
3380 loop->_body.push(n_clone);
3381 _igvn.register_new_node_with_optimizer(n_clone);
3382 set_ctrl(n_clone, get_ctrl(n));
3383 sink_list.push(n_clone);
3384 not_peel.set(n_clone->_idx);
3385 #ifndef PRODUCT
3386 if (TracePartialPeeling) {
3387 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
3388 }
3389 #endif
3390 while( worklist.size() ) {
3391 Node *use = worklist.pop();
3392 _igvn.rehash_node_delayed(use);
3393 for (uint j = 1; j < use->req(); j++) {
3394 if (use->in(j) == n) {
3395 use->set_req(j, n_clone);
3396 }
3397 }
3398 }
3399 }
3400 }
3401
3402
3403 //------------------------------ insert_phi_for_loop -------------------------------------
3404 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
3405 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
3406 Node *phi = PhiNode::make(lp, back_edge_val);
3407 phi->set_req(LoopNode::EntryControl, lp_entry_val);
3408 // Use existing phi if it already exists
3409 Node *hit = _igvn.hash_find_insert(phi);
3410 if( hit == nullptr ) {
3411 _igvn.register_new_node_with_optimizer(phi);
3412 set_ctrl(phi, lp);
3413 } else {
3414 // Remove the new phi from the graph and use the hit
3415 _igvn.remove_dead_node(phi);
3416 phi = hit;
3417 }
3418 _igvn.replace_input_of(use, idx, phi);
3419 }
3420
3421 #ifdef ASSERT
3422 //------------------------------ is_valid_loop_partition -------------------------------------
3423 // Validate the loop partition sets: peel and not_peel
3424 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
3425 VectorSet& not_peel ) {
3426 uint i;
3427 // Check that peel_list entries are in the peel set
3428 for (i = 0; i < peel_list.size(); i++) {
3429 if (!peel.test(peel_list.at(i)->_idx)) {
3430 return false;
3431 }
3432 }
3433 // Check at loop members are in one of peel set or not_peel set
3434 for (i = 0; i < loop->_body.size(); i++ ) {
3435 Node *def = loop->_body.at(i);
3436 uint di = def->_idx;
3437 // Check that peel set elements are in peel_list
3438 if (peel.test(di)) {
3439 if (not_peel.test(di)) {
3440 return false;
3441 }
3442 // Must be in peel_list also
3443 bool found = false;
3444 for (uint j = 0; j < peel_list.size(); j++) {
3445 if (peel_list.at(j)->_idx == di) {
3446 found = true;
3447 break;
3448 }
3449 }
3450 if (!found) {
3451 return false;
3452 }
3453 } else if (not_peel.test(di)) {
3454 if (peel.test(di)) {
3455 return false;
3456 }
3457 } else {
3458 return false;
3459 }
3460 }
3461 return true;
3462 }
3463
3464 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
3465 // Ensure a use outside of loop is of the right form
3466 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
3467 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3468 return (use->is_Phi() &&
3469 use_c->is_Region() && use_c->req() == 3 &&
3470 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
3471 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
3472 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
3473 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
3474 }
3475
3476 //------------------------------ is_valid_clone_loop_form -------------------------------------
3477 // Ensure that all uses outside of loop are of the right form
3478 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
3479 uint orig_exit_idx, uint clone_exit_idx) {
3480 uint len = peel_list.size();
3481 for (uint i = 0; i < len; i++) {
3482 Node *def = peel_list.at(i);
3483
3484 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3485 Node *use = def->fast_out(j);
3486 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3487 if (!loop->is_member(get_loop(use_c))) {
3488 // use is not in the loop, check for correct structure
3489 if (use->in(0) == def) {
3490 // Okay
3491 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
3492 return false;
3493 }
3494 }
3495 }
3496 }
3497 return true;
3498 }
3499 #endif
3500
3501 //------------------------------ partial_peel -------------------------------------
3502 // Partially peel (aka loop rotation) the top portion of a loop (called
3503 // the peel section below) by cloning it and placing one copy just before
3504 // the new loop head and the other copy at the bottom of the new loop.
3505 //
3506 // before after where it came from
3507 //
3508 // stmt1 stmt1
3509 // loop: stmt2 clone
3510 // stmt2 if condA goto exitA clone
3511 // if condA goto exitA new_loop: new
3512 // stmt3 stmt3 clone
3513 // if !condB goto loop if condB goto exitB clone
3514 // exitB: stmt2 orig
3515 // stmt4 if !condA goto new_loop orig
3516 // exitA: goto exitA
3517 // exitB:
3518 // stmt4
3519 // exitA:
3520 //
3521 // Step 1: find the cut point: an exit test on probable
3522 // induction variable.
3523 // Step 2: schedule (with cloning) operations in the peel
3524 // section that can be executed after the cut into
3525 // the section that is not peeled. This may need
3526 // to clone operations into exit blocks. For
3527 // instance, a reference to A[i] in the not-peel
3528 // section and a reference to B[i] in an exit block
3529 // may cause a left-shift of i by 2 to be placed
3530 // in the peel block. This step will clone the left
3531 // shift into the exit block and sink the left shift
3532 // from the peel to the not-peel section.
3533 // Step 3: clone the loop, retarget the control, and insert
3534 // phis for values that are live across the new loop
3535 // head. This is very dependent on the graph structure
3536 // from clone_loop. It creates region nodes for
3537 // exit control and associated phi nodes for values
3538 // flow out of the loop through that exit. The region
3539 // node is dominated by the clone's control projection.
3540 // So the clone's peel section is placed before the
3541 // new loop head, and the clone's not-peel section is
3542 // forms the top part of the new loop. The original
3543 // peel section forms the tail of the new loop.
3544 // Step 4: update the dominator tree and recompute the
3545 // dominator depth.
3546 //
3547 // orig
3548 //
3549 // stmt1
3550 // |
3551 // v
3552 // predicates
3553 // |
3554 // v
3555 // loop<----+
3556 // | |
3557 // stmt2 |
3558 // | |
3559 // v |
3560 // ifA |
3561 // / | |
3562 // v v |
3563 // false true ^ <-- last_peel
3564 // / | |
3565 // / ===|==cut |
3566 // / stmt3 | <-- first_not_peel
3567 // / | |
3568 // | v |
3569 // v ifB |
3570 // exitA: / \ |
3571 // / \ |
3572 // v v |
3573 // false true |
3574 // / \ |
3575 // / ----+
3576 // |
3577 // v
3578 // exitB:
3579 // stmt4
3580 //
3581 //
3582 // after clone loop
3583 //
3584 // stmt1
3585 // |
3586 // v
3587 // predicates
3588 // / \
3589 // clone / \ orig
3590 // / \
3591 // / \
3592 // v v
3593 // +---->loop loop<----+
3594 // | | | |
3595 // | stmt2 stmt2 |
3596 // | | | |
3597 // | v v |
3598 // | ifA ifA |
3599 // | | \ / | |
3600 // | v v v v |
3601 // ^ true false false true ^ <-- last_peel
3602 // | | ^ \ / | |
3603 // | cut==|== \ \ / ===|==cut |
3604 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3605 // | | dom | | | |
3606 // | v \ 1v v2 v |
3607 // | ifB regionA ifB |
3608 // | / \ | / \ |
3609 // | / \ v / \ |
3610 // | v v exitA: v v |
3611 // | true false false true |
3612 // | / ^ \ / \ |
3613 // +---- \ \ / ----+
3614 // dom \ /
3615 // \ 1v v2
3616 // regionB
3617 // |
3618 // v
3619 // exitB:
3620 // stmt4
3621 //
3622 //
3623 // after partial peel
3624 //
3625 // stmt1
3626 // |
3627 // v
3628 // predicates
3629 // /
3630 // clone / orig
3631 // / TOP
3632 // / \
3633 // v v
3634 // TOP->loop loop----+
3635 // | | |
3636 // stmt2 stmt2 |
3637 // | | |
3638 // v v |
3639 // ifA ifA |
3640 // | \ / | |
3641 // v v v v |
3642 // true false false true | <-- last_peel
3643 // | ^ \ / +------|---+
3644 // +->newloop \ \ / === ==cut | |
3645 // | stmt3 \ \ / TOP | |
3646 // | | dom | | stmt3 | | <-- first_not_peel
3647 // | v \ 1v v2 v | |
3648 // | ifB regionA ifB ^ v
3649 // | / \ | / \ | |
3650 // | / \ v / \ | |
3651 // | v v exitA: v v | |
3652 // | true false false true | |
3653 // | / ^ \ / \ | |
3654 // | | \ \ / v | |
3655 // | | dom \ / TOP | |
3656 // | | \ 1v v2 | |
3657 // ^ v regionB | |
3658 // | | | | |
3659 // | | v ^ v
3660 // | | exitB: | |
3661 // | | stmt4 | |
3662 // | +------------>-----------------+ |
3663 // | |
3664 // +-----------------<---------------------+
3665 //
3666 //
3667 // final graph
3668 //
3669 // stmt1
3670 // |
3671 // v
3672 // predicates
3673 // |
3674 // v
3675 // stmt2 clone
3676 // |
3677 // v
3678 // ........> ifA clone
3679 // : / |
3680 // dom / |
3681 // : v v
3682 // : false true
3683 // : | |
3684 // : | v
3685 // : | newloop<-----+
3686 // : | | |
3687 // : | stmt3 clone |
3688 // : | | |
3689 // : | v |
3690 // : | ifB |
3691 // : | / \ |
3692 // : | v v |
3693 // : | false true |
3694 // : | | | |
3695 // : | v stmt2 |
3696 // : | exitB: | |
3697 // : | stmt4 v |
3698 // : | ifA orig |
3699 // : | / \ |
3700 // : | / \ |
3701 // : | v v |
3702 // : | false true |
3703 // : | / \ |
3704 // : v v -----+
3705 // RegionA
3706 // |
3707 // v
3708 // exitA
3709 //
3710 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3711
3712 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3713 if (!loop->_head->is_Loop()) {
3714 return false;
3715 }
3716 LoopNode *head = loop->_head->as_Loop();
3717
3718 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3719 return false;
3720 }
3721
3722 // Check for complex exit control
3723 for (uint ii = 0; ii < loop->_body.size(); ii++) {
3724 Node *n = loop->_body.at(ii);
3725 int opc = n->Opcode();
3726 if (n->is_Call() ||
3727 opc == Op_Catch ||
3728 opc == Op_CatchProj ||
3729 opc == Op_Jump ||
3730 opc == Op_JumpProj) {
3731 #ifndef PRODUCT
3732 if (TracePartialPeeling) {
3733 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3734 }
3735 #endif
3736 return false;
3737 }
3738 }
3739
3740 int dd = dom_depth(head);
3741
3742 // Step 1: find cut point
3743
3744 // Walk up dominators to loop head looking for first loop exit
3745 // which is executed on every path thru loop.
3746 IfNode *peel_if = nullptr;
3747 IfNode *peel_if_cmpu = nullptr;
3748
3749 Node *iff = loop->tail();
3750 while (iff != head) {
3751 if (iff->is_If()) {
3752 Node *ctrl = get_ctrl(iff->in(1));
3753 if (ctrl->is_top()) return false; // Dead test on live IF.
3754 // If loop-varying exit-test, check for induction variable
3755 if (loop->is_member(get_loop(ctrl)) &&
3756 loop->is_loop_exit(iff) &&
3757 is_possible_iv_test(iff)) {
3758 Node* cmp = iff->in(1)->in(1);
3759 if (cmp->Opcode() == Op_CmpI) {
3760 peel_if = iff->as_If();
3761 } else {
3762 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3763 peel_if_cmpu = iff->as_If();
3764 }
3765 }
3766 }
3767 iff = idom(iff);
3768 }
3769
3770 // Prefer signed compare over unsigned compare.
3771 IfNode* new_peel_if = nullptr;
3772 if (peel_if == nullptr) {
3773 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == nullptr) {
3774 return false; // No peel point found
3775 }
3776 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3777 if (new_peel_if == nullptr) {
3778 return false; // No peel point found
3779 }
3780 peel_if = new_peel_if;
3781 }
3782 Node* last_peel = stay_in_loop(peel_if, loop);
3783 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3784 if (first_not_peeled == nullptr || first_not_peeled == head) {
3785 return false;
3786 }
3787
3788 #ifndef PRODUCT
3789 if (TraceLoopOpts) {
3790 tty->print("PartialPeel ");
3791 loop->dump_head();
3792 }
3793
3794 if (TracePartialPeeling) {
3795 tty->print_cr("before partial peel one iteration");
3796 Node_List wl;
3797 Node* t = head->in(2);
3798 while (true) {
3799 wl.push(t);
3800 if (t == head) break;
3801 t = idom(t);
3802 }
3803 while (wl.size() > 0) {
3804 Node* tt = wl.pop();
3805 tt->dump();
3806 if (tt == last_peel) tty->print_cr("-- cut --");
3807 }
3808 }
3809 #endif
3810
3811 C->print_method(PHASE_BEFORE_PARTIAL_PEELING, 4, head);
3812
3813 VectorSet peel;
3814 VectorSet not_peel;
3815 Node_List peel_list;
3816 Node_List worklist;
3817 Node_List sink_list;
3818
3819 uint estimate = loop->est_loop_clone_sz(1);
3820 if (exceeding_node_budget(estimate)) {
3821 return false;
3822 }
3823
3824 // Set of cfg nodes to peel are those that are executable from
3825 // the head through last_peel.
3826 assert(worklist.size() == 0, "should be empty");
3827 worklist.push(head);
3828 peel.set(head->_idx);
3829 while (worklist.size() > 0) {
3830 Node *n = worklist.pop();
3831 if (n != last_peel) {
3832 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3833 Node* use = n->fast_out(j);
3834 if (use->is_CFG() &&
3835 loop->is_member(get_loop(use)) &&
3836 !peel.test_set(use->_idx)) {
3837 worklist.push(use);
3838 }
3839 }
3840 }
3841 }
3842
3843 // Set of non-cfg nodes to peel are those that are control
3844 // dependent on the cfg nodes.
3845 for (uint i = 0; i < loop->_body.size(); i++) {
3846 Node *n = loop->_body.at(i);
3847 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3848 if (peel.test(n_c->_idx)) {
3849 peel.set(n->_idx);
3850 } else {
3851 not_peel.set(n->_idx);
3852 }
3853 }
3854
3855 // Step 2: move operations from the peeled section down into the
3856 // not-peeled section
3857
3858 // Get a post order schedule of nodes in the peel region
3859 // Result in right-most operand.
3860 scheduled_nodelist(loop, peel, peel_list);
3861
3862 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3863
3864 // For future check for too many new phis
3865 uint old_phi_cnt = 0;
3866 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3867 Node* use = head->fast_out(j);
3868 if (use->is_Phi()) old_phi_cnt++;
3869 }
3870
3871 #ifndef PRODUCT
3872 if (TracePartialPeeling) {
3873 tty->print_cr("\npeeled list");
3874 }
3875 #endif
3876
3877 // Evacuate nodes in peel region into the not_peeled region if possible
3878 bool too_many_clones = false;
3879 uint new_phi_cnt = 0;
3880 uint cloned_for_outside_use = 0;
3881 for (uint i = 0; i < peel_list.size();) {
3882 Node* n = peel_list.at(i);
3883 #ifndef PRODUCT
3884 if (TracePartialPeeling) n->dump();
3885 #endif
3886 bool incr = true;
3887 if (!n->is_CFG()) {
3888 if (has_use_in_set(n, not_peel)) {
3889 // If not used internal to the peeled region,
3890 // move "n" from peeled to not_peeled region.
3891 if (!has_use_internal_to_set(n, peel, loop)) {
3892 // if not pinned and not a load (which maybe anti-dependent on a store)
3893 // and not a CMove (Matcher expects only bool->cmove).
3894 if (n->in(0) == nullptr && !n->is_Load() && !n->is_CMove()) {
3895 int new_clones = clone_for_use_outside_loop(loop, n, worklist);
3896 if (C->failing()) return false;
3897 if (new_clones == -1) {
3898 too_many_clones = true;
3899 break;
3900 }
3901 cloned_for_outside_use += new_clones;
3902 sink_list.push(n);
3903 peel.remove(n->_idx);
3904 not_peel.set(n->_idx);
3905 peel_list.remove(i);
3906 incr = false;
3907 #ifndef PRODUCT
3908 if (TracePartialPeeling) {
3909 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3910 n->_idx, get_ctrl(n)->_idx);
3911 }
3912 #endif
3913 }
3914 } else {
3915 // Otherwise check for special def-use cases that span
3916 // the peel/not_peel boundary such as bool->if
3917 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist);
3918 new_phi_cnt++;
3919 }
3920 }
3921 }
3922 if (incr) i++;
3923 }
3924
3925 estimate += cloned_for_outside_use + new_phi_cnt;
3926 bool exceed_node_budget = !may_require_nodes(estimate);
3927 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta;
3928
3929 if (too_many_clones || exceed_node_budget || exceed_phi_limit) {
3930 #ifndef PRODUCT
3931 if (TracePartialPeeling && exceed_phi_limit) {
3932 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3933 new_phi_cnt, old_phi_cnt, new_peel_if != nullptr?'T':'F');
3934 }
3935 #endif
3936 if (new_peel_if != nullptr) {
3937 remove_cmpi_loop_exit(new_peel_if, loop);
3938 }
3939 // Inhibit more partial peeling on this loop
3940 assert(!head->is_partial_peel_loop(), "not partial peeled");
3941 head->mark_partial_peel_failed();
3942 if (cloned_for_outside_use > 0) {
3943 // Terminate this round of loop opts because
3944 // the graph outside this loop was changed.
3945 C->set_major_progress();
3946 return true;
3947 }
3948 return false;
3949 }
3950
3951 // Step 3: clone loop, retarget control, and insert new phis
3952
3953 // Create new loop head for new phis and to hang
3954 // the nodes being moved (sinked) from the peel region.
3955 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3956 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3957 _igvn.register_new_node_with_optimizer(new_head);
3958 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3959 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3960 set_loop(new_head, loop);
3961 loop->_body.push(new_head);
3962 not_peel.set(new_head->_idx);
3963 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3964 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3965
3966 while (sink_list.size() > 0) {
3967 Node* n = sink_list.pop();
3968 set_ctrl(n, new_head);
3969 }
3970
3971 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3972
3973 clone_loop(loop, old_new, dd, IgnoreStripMined);
3974
3975 const uint clone_exit_idx = 1;
3976 const uint orig_exit_idx = 2;
3977 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop");
3978
3979 Node* head_clone = old_new[head->_idx];
3980 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3981 Node* orig_tail_clone = head_clone->in(2);
3982
3983 // Add phi if "def" node is in peel set and "use" is not
3984
3985 for (uint i = 0; i < peel_list.size(); i++) {
3986 Node *def = peel_list.at(i);
3987 if (!def->is_CFG()) {
3988 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3989 Node *use = def->fast_out(j);
3990 if (has_node(use) && use->in(0) != C->top() &&
3991 (!peel.test(use->_idx) ||
3992 (use->is_Phi() && use->in(0) == head)) ) {
3993 worklist.push(use);
3994 }
3995 }
3996 while( worklist.size() ) {
3997 Node *use = worklist.pop();
3998 for (uint j = 1; j < use->req(); j++) {
3999 Node* n = use->in(j);
4000 if (n == def) {
4001
4002 // "def" is in peel set, "use" is not in peel set
4003 // or "use" is in the entry boundary (a phi) of the peel set
4004
4005 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
4006
4007 if ( loop->is_member(get_loop( use_c )) ) {
4008 // use is in loop
4009 if (old_new[use->_idx] != nullptr) { // null for dead code
4010 Node* use_clone = old_new[use->_idx];
4011 _igvn.replace_input_of(use, j, C->top());
4012 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
4013 }
4014 } else {
4015 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
4016 // use is not in the loop, check if the live range includes the cut
4017 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
4018 if (not_peel.test(lp_if->_idx)) {
4019 assert(j == orig_exit_idx, "use from original loop");
4020 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
4021 }
4022 }
4023 }
4024 }
4025 }
4026 }
4027 }
4028
4029 // Step 3b: retarget control
4030
4031 // Redirect control to the new loop head if a cloned node in
4032 // the not_peeled region has control that points into the peeled region.
4033 // This necessary because the cloned peeled region will be outside
4034 // the loop.
4035 // from to
4036 // cloned-peeled <---+
4037 // new_head_clone: | <--+
4038 // cloned-not_peeled in(0) in(0)
4039 // orig-peeled
4040
4041 for (uint i = 0; i < loop->_body.size(); i++) {
4042 Node *n = loop->_body.at(i);
4043 if (!n->is_CFG() && n->in(0) != nullptr &&
4044 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
4045 Node* n_clone = old_new[n->_idx];
4046 _igvn.replace_input_of(n_clone, 0, new_head_clone);
4047 }
4048 }
4049
4050 // Backedge of the surviving new_head (the clone) is original last_peel
4051 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
4052
4053 // Cut first node in original not_peel set
4054 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
4055 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
4056 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
4057
4058 // Copy head_clone back-branch info to original head
4059 // and remove original head's loop entry and
4060 // clone head's back-branch
4061 _igvn.rehash_node_delayed(head); // Multiple edge updates
4062 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
4063 head->set_req(LoopNode::LoopBackControl, C->top());
4064 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
4065
4066 // Similarly modify the phis
4067 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
4068 Node* use = head->fast_out(k);
4069 if (use->is_Phi() && use->outcnt() > 0) {
4070 Node* use_clone = old_new[use->_idx];
4071 _igvn.rehash_node_delayed(use); // Multiple edge updates
4072 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
4073 use->set_req(LoopNode::LoopBackControl, C->top());
4074 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
4075 }
4076 }
4077
4078 // Step 4: update dominator tree and dominator depth
4079
4080 set_idom(head, orig_tail_clone, dd);
4081 recompute_dom_depth();
4082
4083 // Inhibit more partial peeling on this loop
4084 new_head_clone->set_partial_peel_loop();
4085 C->set_major_progress();
4086 loop->record_for_igvn();
4087
4088 #ifndef PRODUCT
4089 if (TracePartialPeeling) {
4090 tty->print_cr("\nafter partial peel one iteration");
4091 Node_List wl;
4092 Node* t = last_peel;
4093 while (true) {
4094 wl.push(t);
4095 if (t == head_clone) break;
4096 t = idom(t);
4097 }
4098 while (wl.size() > 0) {
4099 Node* tt = wl.pop();
4100 if (tt == head) tty->print_cr("orig head");
4101 else if (tt == new_head_clone) tty->print_cr("new head");
4102 else if (tt == head_clone) tty->print_cr("clone head");
4103 tt->dump();
4104 }
4105 }
4106 #endif
4107
4108 C->print_method(PHASE_AFTER_PARTIAL_PEELING, 4, new_head_clone);
4109
4110 return true;
4111 }
4112
4113 // Transform:
4114 //
4115 // loop<-----------------+
4116 // | |
4117 // stmt1 stmt2 .. stmtn |
4118 // | | | |
4119 // \ | / |
4120 // v v v |
4121 // region |
4122 // | |
4123 // shared_stmt |
4124 // | |
4125 // v |
4126 // if |
4127 // / \ |
4128 // | -----------+
4129 // v
4130 //
4131 // into:
4132 //
4133 // loop<-------------------+
4134 // | |
4135 // v |
4136 // +->loop |
4137 // | | |
4138 // | stmt1 stmt2 .. stmtn |
4139 // | | | | |
4140 // | | \ / |
4141 // | | v v |
4142 // | | region1 |
4143 // | | | |
4144 // | shared_stmt shared_stmt |
4145 // | | | |
4146 // | v v |
4147 // | if if |
4148 // | /\ / \ |
4149 // +-- | | -------+
4150 // \ /
4151 // v v
4152 // region2
4153 //
4154 // (region2 is shown to merge mirrored projections of the loop exit
4155 // ifs to make the diagram clearer but they really merge the same
4156 // projection)
4157 //
4158 // Conditions for this transformation to trigger:
4159 // - the path through stmt1 is frequent enough
4160 // - the inner loop will be turned into a counted loop after transformation
4161 bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new) {
4162 if (!DuplicateBackedge) {
4163 return false;
4164 }
4165 assert(!loop->_head->is_CountedLoop() || StressDuplicateBackedge, "Non-counted loop only");
4166 if (!loop->_head->is_Loop()) {
4167 return false;
4168 }
4169
4170 uint estimate = loop->est_loop_clone_sz(1);
4171 if (exceeding_node_budget(estimate)) {
4172 return false;
4173 }
4174
4175 LoopNode *head = loop->_head->as_Loop();
4176
4177 Node* region = nullptr;
4178 IfNode* exit_test = nullptr;
4179 uint inner;
4180 float f;
4181 if (StressDuplicateBackedge) {
4182 if (head->is_strip_mined()) {
4183 return false;
4184 }
4185 Node* c = head->in(LoopNode::LoopBackControl);
4186
4187 while (c != head) {
4188 if (c->is_Region()) {
4189 region = c;
4190 }
4191 c = idom(c);
4192 }
4193
4194 if (region == nullptr) {
4195 return false;
4196 }
4197
4198 inner = 1;
4199 } else {
4200 // Is the shape of the loop that of a counted loop...
4201 Node* back_control = loop_exit_control(head, loop);
4202 if (back_control == nullptr) {
4203 return false;
4204 }
4205
4206 BoolTest::mask bt = BoolTest::illegal;
4207 float cl_prob = 0;
4208 Node* incr = nullptr;
4209 Node* limit = nullptr;
4210 Node* cmp = loop_exit_test(back_control, loop, incr, limit, bt, cl_prob);
4211 if (cmp == nullptr || cmp->Opcode() != Op_CmpI) {
4212 return false;
4213 }
4214
4215 // With an extra phi for the candidate iv?
4216 // Or the region node is the loop head
4217 if (!incr->is_Phi() || incr->in(0) == head) {
4218 return false;
4219 }
4220
4221 PathFrequency pf(head, this);
4222 region = incr->in(0);
4223
4224 // Go over all paths for the extra phi's region and see if that
4225 // path is frequent enough and would match the expected iv shape
4226 // if the extra phi is removed
4227 inner = 0;
4228 for (uint i = 1; i < incr->req(); ++i) {
4229 Node* in = incr->in(i);
4230 Node* trunc1 = nullptr;
4231 Node* trunc2 = nullptr;
4232 const TypeInteger* iv_trunc_t = nullptr;
4233 Node* orig_in = in;
4234 if (!(in = CountedLoopNode::match_incr_with_optional_truncation(in, &trunc1, &trunc2, &iv_trunc_t, T_INT))) {
4235 continue;
4236 }
4237 assert(in->Opcode() == Op_AddI, "wrong increment code");
4238 Node* xphi = nullptr;
4239 Node* stride = loop_iv_stride(in, loop, xphi);
4240
4241 if (stride == nullptr) {
4242 continue;
4243 }
4244
4245 PhiNode* phi = loop_iv_phi(xphi, nullptr, head, loop);
4246 if (phi == nullptr ||
4247 (trunc1 == nullptr && phi->in(LoopNode::LoopBackControl) != incr) ||
4248 (trunc1 != nullptr && phi->in(LoopNode::LoopBackControl) != trunc1)) {
4249 return false;
4250 }
4251
4252 f = pf.to(region->in(i));
4253 if (f > 0.5) {
4254 inner = i;
4255 break;
4256 }
4257 }
4258
4259 if (inner == 0) {
4260 return false;
4261 }
4262
4263 exit_test = back_control->in(0)->as_If();
4264 }
4265
4266 if (idom(region)->is_Catch()) {
4267 return false;
4268 }
4269
4270 // Collect all control nodes that need to be cloned (shared_stmt in the diagram)
4271 Unique_Node_List wq;
4272 wq.push(head->in(LoopNode::LoopBackControl));
4273 for (uint i = 0; i < wq.size(); i++) {
4274 Node* c = wq.at(i);
4275 assert(get_loop(c) == loop, "not in the right loop?");
4276 if (c->is_Region()) {
4277 if (c != region) {
4278 for (uint j = 1; j < c->req(); ++j) {
4279 wq.push(c->in(j));
4280 }
4281 }
4282 } else {
4283 wq.push(c->in(0));
4284 }
4285 assert(!is_dominator(c, region) || c == region, "shouldn't go above region");
4286 }
4287
4288 Node* region_dom = idom(region);
4289
4290 // Can't do the transformation if this would cause a membar pair to
4291 // be split
4292 for (uint i = 0; i < wq.size(); i++) {
4293 Node* c = wq.at(i);
4294 if (c->is_MemBar() && (c->as_MemBar()->trailing_store() || c->as_MemBar()->trailing_load_store())) {
4295 assert(c->as_MemBar()->leading_membar()->trailing_membar() == c, "bad membar pair");
4296 if (!wq.member(c->as_MemBar()->leading_membar())) {
4297 return false;
4298 }
4299 }
4300 }
4301
4302 // Collect data nodes that need to be clones as well
4303 int dd = dom_depth(head);
4304
4305 for (uint i = 0; i < loop->_body.size(); ++i) {
4306 Node* n = loop->_body.at(i);
4307 if (has_ctrl(n)) {
4308 Node* c = get_ctrl(n);
4309 if (wq.member(c)) {
4310 wq.push(n);
4311 }
4312 } else {
4313 set_idom(n, idom(n), dd);
4314 }
4315 }
4316
4317 // clone shared_stmt
4318 clone_loop_body(wq, old_new, nullptr);
4319
4320 Node* region_clone = old_new[region->_idx];
4321 region_clone->set_req(inner, C->top());
4322 set_idom(region, region->in(inner), dd);
4323
4324 // Prepare the outer loop
4325 Node* outer_head = new LoopNode(head->in(LoopNode::EntryControl), old_new[head->in(LoopNode::LoopBackControl)->_idx]);
4326 register_control(outer_head, loop->_parent, outer_head->in(LoopNode::EntryControl));
4327 _igvn.replace_input_of(head, LoopNode::EntryControl, outer_head);
4328 set_idom(head, outer_head, dd);
4329
4330 fix_body_edges(wq, loop, old_new, dd, loop->_parent, true);
4331
4332 // Make one of the shared_stmt copies only reachable from stmt1, the
4333 // other only from stmt2..stmtn.
4334 Node* dom = nullptr;
4335 for (uint i = 1; i < region->req(); ++i) {
4336 if (i != inner) {
4337 _igvn.replace_input_of(region, i, C->top());
4338 }
4339 Node* in = region_clone->in(i);
4340 if (in->is_top()) {
4341 continue;
4342 }
4343 if (dom == nullptr) {
4344 dom = in;
4345 } else {
4346 dom = dom_lca(dom, in);
4347 }
4348 }
4349
4350 set_idom(region_clone, dom, dd);
4351
4352 // Set up the outer loop
4353 for (uint i = 0; i < head->outcnt(); i++) {
4354 Node* u = head->raw_out(i);
4355 if (u->is_Phi()) {
4356 Node* outer_phi = u->clone();
4357 outer_phi->set_req(0, outer_head);
4358 Node* backedge = old_new[u->in(LoopNode::LoopBackControl)->_idx];
4359 if (backedge == nullptr) {
4360 backedge = u->in(LoopNode::LoopBackControl);
4361 }
4362 outer_phi->set_req(LoopNode::LoopBackControl, backedge);
4363 register_new_node(outer_phi, outer_head);
4364 _igvn.replace_input_of(u, LoopNode::EntryControl, outer_phi);
4365 }
4366 }
4367
4368 // create control and data nodes for out of loop uses (including region2)
4369 Node_List worklist;
4370 uint new_counter = C->unique();
4371 fix_ctrl_uses(wq, loop, old_new, ControlAroundStripMined, outer_head, nullptr, worklist);
4372
4373 Node_List *split_if_set = nullptr;
4374 Node_List *split_bool_set = nullptr;
4375 Node_List *split_cex_set = nullptr;
4376 fix_data_uses(wq, loop, ControlAroundStripMined, head->is_strip_mined() ? loop->_parent : loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
4377
4378 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
4379
4380 if (exit_test != nullptr) {
4381 float cnt = exit_test->_fcnt;
4382 if (cnt != COUNT_UNKNOWN) {
4383 exit_test->_fcnt = cnt * f;
4384 old_new[exit_test->_idx]->as_If()->_fcnt = cnt * (1 - f);
4385 }
4386 }
4387
4388 C->set_major_progress();
4389
4390 return true;
4391 }
4392
4393 // AutoVectorize the loop: replace scalar ops with vector ops.
4394 PhaseIdealLoop::AutoVectorizeStatus
4395 PhaseIdealLoop::auto_vectorize(IdealLoopTree* lpt, VSharedData &vshared) {
4396 // Counted loop only
4397 if (!lpt->is_counted()) {
4398 return AutoVectorizeStatus::Impossible;
4399 }
4400
4401 // Main-loop only
4402 CountedLoopNode* cl = lpt->_head->as_CountedLoop();
4403 if (!cl->is_main_loop()) {
4404 return AutoVectorizeStatus::Impossible;
4405 }
4406
4407 VLoop vloop(lpt, false);
4408 if (!vloop.check_preconditions()) {
4409 return AutoVectorizeStatus::TriedAndFailed;
4410 }
4411
4412 // Ensure the shared data is cleared before each use
4413 vshared.clear();
4414
4415 SuperWord sw(vloop, vshared);
4416 if (!sw.transform_loop()) {
4417 return AutoVectorizeStatus::TriedAndFailed;
4418 }
4419
4420 return AutoVectorizeStatus::Success;
4421 }
4422
4423 // Having ReductionNodes in the loop is expensive. They need to recursively
4424 // fold together the vector values, for every vectorized loop iteration. If
4425 // we encounter the following pattern, we can vector accumulate the values
4426 // inside the loop, and only have a single UnorderedReduction after the loop.
4427 //
4428 // CountedLoop init
4429 // | |
4430 // +------+ | +-----------------------+
4431 // | | | |
4432 // PhiNode (s) |
4433 // | |
4434 // | Vector |
4435 // | | |
4436 // UnorderedReduction (first_ur) |
4437 // | |
4438 // ... Vector |
4439 // | | |
4440 // UnorderedReduction (last_ur) |
4441 // | |
4442 // +---------------------+
4443 //
4444 // We patch the graph to look like this:
4445 //
4446 // CountedLoop identity_vector
4447 // | |
4448 // +-------+ | +---------------+
4449 // | | | |
4450 // PhiNode (v) |
4451 // | |
4452 // | Vector |
4453 // | | |
4454 // VectorAccumulator |
4455 // | |
4456 // ... Vector |
4457 // | | |
4458 // init VectorAccumulator |
4459 // | | | |
4460 // UnorderedReduction +-----------+
4461 //
4462 // We turned the scalar (s) Phi into a vectorized one (v). In the loop, we
4463 // use vector_accumulators, which do the same reductions, but only element
4464 // wise. This is a single operation per vector_accumulator, rather than many
4465 // for a UnorderedReduction. We can then reduce the last vector_accumulator
4466 // after the loop, and also reduce the init value into it.
4467 // We can not do this with all reductions. Some reductions do not allow the
4468 // reordering of operations (for example float addition).
4469 void PhaseIdealLoop::move_unordered_reduction_out_of_loop(IdealLoopTree* loop) {
4470 assert(!C->major_progress() && loop->is_counted() && loop->is_innermost(), "sanity");
4471
4472 // Find all Phi nodes with UnorderedReduction on backedge.
4473 CountedLoopNode* cl = loop->_head->as_CountedLoop();
4474 for (DUIterator_Fast jmax, j = cl->fast_outs(jmax); j < jmax; j++) {
4475 Node* phi = cl->fast_out(j);
4476 // We have a phi with a single use, and a UnorderedReduction on the backedge.
4477 if (!phi->is_Phi() || phi->outcnt() != 1 || !phi->in(2)->is_UnorderedReduction()) {
4478 continue;
4479 }
4480
4481 UnorderedReductionNode* last_ur = phi->in(2)->as_UnorderedReduction();
4482
4483 // Determine types
4484 const TypeVect* vec_t = last_ur->vect_type();
4485 uint vector_length = vec_t->length();
4486 BasicType bt = vec_t->element_basic_type();
4487 const Type* bt_t = Type::get_const_basic_type(bt);
4488
4489 // Convert opcode from vector-reduction -> scalar -> normal-vector-op
4490 const int sopc = VectorNode::scalar_opcode(last_ur->Opcode(), bt);
4491 const int vopc = VectorNode::opcode(sopc, bt);
4492 if (!Matcher::match_rule_supported_vector(vopc, vector_length, bt)) {
4493 DEBUG_ONLY( last_ur->dump(); )
4494 assert(false, "do not have normal vector op for this reduction");
4495 continue; // not implemented -> fails
4496 }
4497
4498 // Traverse up the chain of UnorderedReductions, checking that it loops back to
4499 // the phi. Check that all UnorderedReductions only have a single use, except for
4500 // the last (last_ur), which only has phi as a use in the loop, and all other uses
4501 // are outside the loop.
4502 UnorderedReductionNode* current = last_ur;
4503 UnorderedReductionNode* first_ur = nullptr;
4504 while (true) {
4505 assert(current->is_UnorderedReduction(), "sanity");
4506
4507 // Expect no ctrl and a vector_input from within the loop.
4508 Node* ctrl = current->in(0);
4509 Node* vector_input = current->in(2);
4510 if (ctrl != nullptr || get_ctrl(vector_input) != cl) {
4511 DEBUG_ONLY( current->dump(1); )
4512 assert(false, "reduction has ctrl or bad vector_input");
4513 break; // Chain traversal fails.
4514 }
4515
4516 assert(current->vect_type() != nullptr, "must have vector type");
4517 if (current->vect_type() != last_ur->vect_type()) {
4518 // Reductions do not have the same vector type (length and element type).
4519 break; // Chain traversal fails.
4520 }
4521
4522 // Expect single use of UnorderedReduction, except for last_ur.
4523 if (current == last_ur) {
4524 // Expect all uses to be outside the loop, except phi.
4525 for (DUIterator_Fast kmax, k = current->fast_outs(kmax); k < kmax; k++) {
4526 Node* use = current->fast_out(k);
4527 if (use != phi && ctrl_or_self(use) == cl) {
4528 DEBUG_ONLY( current->dump(-1); )
4529 assert(false, "reduction has use inside loop");
4530 // Should not be allowed by SuperWord::mark_reductions
4531 return; // bail out of optimization
4532 }
4533 }
4534 } else {
4535 if (current->outcnt() != 1) {
4536 break; // Chain traversal fails.
4537 }
4538 }
4539
4540 // Expect another UnorderedReduction or phi as the scalar input.
4541 Node* scalar_input = current->in(1);
4542 if (scalar_input->is_UnorderedReduction() &&
4543 scalar_input->Opcode() == current->Opcode()) {
4544 // Move up the UnorderedReduction chain.
4545 current = scalar_input->as_UnorderedReduction();
4546 } else if (scalar_input == phi) {
4547 // Chain terminates at phi.
4548 first_ur = current;
4549 current = nullptr;
4550 break; // Success.
4551 } else {
4552 // scalar_input is neither phi nor a matching reduction
4553 // Can for example be scalar reduction when we have
4554 // partial vectorization.
4555 break; // Chain traversal fails.
4556 }
4557 }
4558 if (current != nullptr) {
4559 // Chain traversal was not successful.
4560 continue;
4561 }
4562 assert(first_ur != nullptr, "must have successfully terminated chain traversal");
4563
4564 Node* identity_scalar = ReductionNode::make_identity_con_scalar(_igvn, sopc, bt);
4565 set_ctrl(identity_scalar, C->root());
4566 VectorNode* identity_vector = VectorNode::scalar2vector(identity_scalar, vector_length, bt_t);
4567 register_new_node(identity_vector, C->root());
4568 assert(vec_t == identity_vector->vect_type(), "matching vector type");
4569 VectorNode::trace_new_vector(identity_vector, "UnorderedReduction");
4570
4571 // Turn the scalar phi into a vector phi.
4572 _igvn.rehash_node_delayed(phi);
4573 Node* init = phi->in(1); // Remember init before replacing it.
4574 phi->set_req_X(1, identity_vector, &_igvn);
4575 phi->as_Type()->set_type(vec_t);
4576 _igvn.set_type(phi, vec_t);
4577
4578 // Traverse down the chain of UnorderedReductions, and replace them with vector_accumulators.
4579 current = first_ur;
4580 while (true) {
4581 // Create vector_accumulator to replace current.
4582 Node* last_vector_accumulator = current->in(1);
4583 Node* vector_input = current->in(2);
4584 VectorNode* vector_accumulator = VectorNode::make(vopc, last_vector_accumulator, vector_input, vec_t);
4585 register_new_node(vector_accumulator, cl);
4586 _igvn.replace_node(current, vector_accumulator);
4587 VectorNode::trace_new_vector(vector_accumulator, "UnorderedReduction");
4588 if (current == last_ur) {
4589 break;
4590 }
4591 current = vector_accumulator->unique_out()->as_UnorderedReduction();
4592 }
4593
4594 // Create post-loop reduction.
4595 Node* last_accumulator = phi->in(2);
4596 Node* post_loop_reduction = ReductionNode::make(sopc, nullptr, init, last_accumulator, bt);
4597
4598 // Take over uses of last_accumulator that are not in the loop.
4599 for (DUIterator i = last_accumulator->outs(); last_accumulator->has_out(i); i++) {
4600 Node* use = last_accumulator->out(i);
4601 if (use != phi && use != post_loop_reduction) {
4602 assert(ctrl_or_self(use) != cl, "use must be outside loop");
4603 use->replace_edge(last_accumulator, post_loop_reduction, &_igvn);
4604 --i;
4605 }
4606 }
4607 register_new_node(post_loop_reduction, get_late_ctrl(post_loop_reduction, cl));
4608 VectorNode::trace_new_vector(post_loop_reduction, "UnorderedReduction");
4609
4610 assert(last_accumulator->outcnt() == 2, "last_accumulator has 2 uses: phi and post_loop_reduction");
4611 assert(post_loop_reduction->outcnt() > 0, "should have taken over all non loop uses of last_accumulator");
4612 assert(phi->outcnt() == 1, "accumulator is the only use of phi");
4613 }
4614 }