1 /*
2 * Copyright (c) 1999, 2025, 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,
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23 */
24
25 #include "gc/shared/barrierSet.hpp"
26 #include "gc/shared/c2/barrierSetC2.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "opto/addnode.hpp"
30 #include "opto/callnode.hpp"
31 #include "opto/castnode.hpp"
32 #include "opto/connode.hpp"
33 #include "opto/castnode.hpp"
34 #include "opto/divnode.hpp"
35 #include "opto/loopnode.hpp"
36 #include "opto/matcher.hpp"
37 #include "opto/mulnode.hpp"
38 #include "opto/movenode.hpp"
39 #include "opto/opaquenode.hpp"
40 #include "opto/rootnode.hpp"
41 #include "opto/subnode.hpp"
42 #include "opto/subtypenode.hpp"
43 #include "opto/superword.hpp"
44 #include "opto/vectornode.hpp"
45 #include "utilities/macros.hpp"
46
47 //=============================================================================
48 //------------------------------split_thru_phi---------------------------------
49 // Split Node 'n' through merge point if there is enough win.
50 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) {
51 if ((n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) ||
52 (n->Opcode() == Op_ConvL2I && n->bottom_type() != TypeInt::INT)) {
53 // ConvI2L/ConvL2I may have type information on it which is unsafe to push up
54 // so disable this for now
55 return nullptr;
56 }
57
58 // Splitting range check CastIIs through a loop induction Phi can
59 // cause new Phis to be created that are left unrelated to the loop
60 // induction Phi and prevent optimizations (vectorization)
61 if (n->Opcode() == Op_CastII && region->is_CountedLoop() &&
62 n->in(1) == region->as_CountedLoop()->phi()) {
63 return nullptr;
64 }
65
66 if (cannot_split_division(n, region)) {
67 return nullptr;
68 }
69
70 int wins = 0;
71 assert(!n->is_CFG(), "");
72 assert(region->is_Region(), "");
73
74 const Type* type = n->bottom_type();
75 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr();
76 Node* phi;
77 if (t_oop != nullptr && t_oop->is_known_instance_field()) {
78 int iid = t_oop->instance_id();
79 int index = C->get_alias_index(t_oop);
80 int offset = t_oop->offset();
81 phi = new PhiNode(region, type, nullptr, iid, index, offset);
82 } else {
83 phi = PhiNode::make_blank(region, n);
84 }
85 uint old_unique = C->unique();
86 for (uint i = 1; i < region->req(); i++) {
87 Node* x;
88 Node* the_clone = nullptr;
89 if (region->in(i) == C->top()) {
90 x = C->top(); // Dead path? Use a dead data op
91 } else {
92 x = n->clone(); // Else clone up the data op
93 the_clone = x; // Remember for possible deletion.
94 // Alter data node to use pre-phi inputs
95 if (n->in(0) == region)
96 x->set_req( 0, region->in(i) );
97 for (uint j = 1; j < n->req(); j++) {
98 Node* in = n->in(j);
99 if (in->is_Phi() && in->in(0) == region)
100 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
101 }
102 }
103 // Check for a 'win' on some paths
104 const Type* t = x->Value(&_igvn);
105
106 bool singleton = t->singleton();
107
108 // A TOP singleton indicates that there are no possible values incoming
109 // along a particular edge. In most cases, this is OK, and the Phi will
110 // be eliminated later in an Ideal call. However, we can't allow this to
111 // happen if the singleton occurs on loop entry, as the elimination of
112 // the PhiNode may cause the resulting node to migrate back to a previous
113 // loop iteration.
114 if (singleton && t == Type::TOP) {
115 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
116 // irreducible loop may not be indicated by an affirmative is_Loop());
117 // therefore, the only top we can split thru a phi is on a backedge of
118 // a loop.
119 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
120 }
121
122 if (singleton) {
123 wins++;
124 x = makecon(t);
125 } else {
126 // We now call Identity to try to simplify the cloned node.
127 // Note that some Identity methods call phase->type(this).
128 // Make sure that the type array is big enough for
129 // our new node, even though we may throw the node away.
130 // (Note: This tweaking with igvn only works because x is a new node.)
131 _igvn.set_type(x, t);
132 // If x is a TypeNode, capture any more-precise type permanently into Node
133 // otherwise it will be not updated during igvn->transform since
134 // igvn->type(x) is set to x->Value() already.
135 x->raise_bottom_type(t);
136 Node* y = x->Identity(&_igvn);
137 if (y != x) {
138 wins++;
139 x = y;
140 } else {
141 y = _igvn.hash_find(x);
142 if (y == nullptr) {
143 y = similar_subtype_check(x, region->in(i));
144 }
145 if (y) {
146 wins++;
147 x = y;
148 } else {
149 // Else x is a new node we are keeping
150 // We do not need register_new_node_with_optimizer
151 // because set_type has already been called.
152 _igvn._worklist.push(x);
153 }
154 }
155 }
156
157 phi->set_req( i, x );
158
159 if (the_clone == nullptr) {
160 continue;
161 }
162
163 if (the_clone != x) {
164 _igvn.remove_dead_node(the_clone);
165 } else if (region->is_Loop() && i == LoopNode::LoopBackControl &&
166 n->is_Load() && can_move_to_inner_loop(n, region->as_Loop(), x)) {
167 // it is not a win if 'x' moved from an outer to an inner loop
168 // this edge case can only happen for Load nodes
169 wins = 0;
170 break;
171 }
172 }
173 // Too few wins?
174 if (wins <= policy) {
175 _igvn.remove_dead_node(phi);
176 return nullptr;
177 }
178
179 // Record Phi
180 register_new_node( phi, region );
181
182 for (uint i2 = 1; i2 < phi->req(); i2++) {
183 Node *x = phi->in(i2);
184 // If we commoned up the cloned 'x' with another existing Node,
185 // the existing Node picks up a new use. We need to make the
186 // existing Node occur higher up so it dominates its uses.
187 Node *old_ctrl;
188 IdealLoopTree *old_loop;
189
190 if (x->is_Con()) {
191 assert(get_ctrl(x) == C->root(), "constant control is not root");
192 continue;
193 }
194 // The occasional new node
195 if (x->_idx >= old_unique) { // Found a new, unplaced node?
196 old_ctrl = nullptr;
197 old_loop = nullptr; // Not in any prior loop
198 } else {
199 old_ctrl = get_ctrl(x);
200 old_loop = get_loop(old_ctrl); // Get prior loop
201 }
202 // New late point must dominate new use
203 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
204 if (new_ctrl == old_ctrl) // Nothing is changed
205 continue;
206
207 IdealLoopTree *new_loop = get_loop(new_ctrl);
208
209 // Don't move x into a loop if its uses are
210 // outside of loop. Otherwise x will be cloned
211 // for each use outside of this loop.
212 IdealLoopTree *use_loop = get_loop(region);
213 if (!new_loop->is_member(use_loop) &&
214 (old_loop == nullptr || !new_loop->is_member(old_loop))) {
215 // Take early control, later control will be recalculated
216 // during next iteration of loop optimizations.
217 new_ctrl = get_early_ctrl(x);
218 new_loop = get_loop(new_ctrl);
219 }
220 // Set new location
221 set_ctrl(x, new_ctrl);
222 // If changing loop bodies, see if we need to collect into new body
223 if (old_loop != new_loop) {
224 if (old_loop && !old_loop->_child)
225 old_loop->_body.yank(x);
226 if (!new_loop->_child)
227 new_loop->_body.push(x); // Collect body info
228 }
229 }
230
231 return phi;
232 }
233
234 // Test whether node 'x' can move into an inner loop relative to node 'n'.
235 // Note: The test is not exact. Returns true if 'x' COULD end up in an inner loop,
236 // BUT it can also return true and 'x' is in the outer loop
237 bool PhaseIdealLoop::can_move_to_inner_loop(Node* n, LoopNode* n_loop, Node* x) {
238 IdealLoopTree* n_loop_tree = get_loop(n_loop);
239 IdealLoopTree* x_loop_tree = get_loop(get_early_ctrl(x));
240 // x_loop_tree should be outer or same loop as n_loop_tree
241 return !x_loop_tree->is_member(n_loop_tree);
242 }
243
244 // Subtype checks that carry profile data don't common so look for a replacement by following edges
245 Node* PhaseIdealLoop::similar_subtype_check(const Node* x, Node* r_in) {
246 if (x->is_SubTypeCheck()) {
247 Node* in1 = x->in(1);
248 for (DUIterator_Fast imax, i = in1->fast_outs(imax); i < imax; i++) {
249 Node* u = in1->fast_out(i);
250 if (u != x && u->is_SubTypeCheck() && u->in(1) == x->in(1) && u->in(2) == x->in(2)) {
251 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) {
252 Node* bol = u->fast_out(j);
253 for (DUIterator_Fast kmax, k = bol->fast_outs(kmax); k < kmax; k++) {
254 Node* iff = bol->fast_out(k);
255 // Only dominating subtype checks are interesting: otherwise we risk replacing a subtype check by another with
256 // unrelated profile
257 if (iff->is_If() && is_dominator(iff, r_in)) {
258 return u;
259 }
260 }
261 }
262 }
263 }
264 }
265 return nullptr;
266 }
267
268 // Return true if 'n' is a Div or Mod node (without zero check If node which was removed earlier) with a loop phi divisor
269 // of a trip-counted (integer or long) loop with a backedge input that could be zero (include zero in its type range). In
270 // this case, we cannot split the division to the backedge as it could freely float above the loop exit check resulting in
271 // a division by zero. This situation is possible because the type of an increment node of an iv phi (trip-counter) could
272 // include zero while the iv phi does not (see PhiNode::Value() for trip-counted loops where we improve types of iv phis).
273 // We also need to check other loop phis as they could have been created in the same split-if pass when applying
274 // PhaseIdealLoop::split_thru_phi() to split nodes through an iv phi.
275 bool PhaseIdealLoop::cannot_split_division(const Node* n, const Node* region) const {
276 const Type* zero;
277 switch (n->Opcode()) {
278 case Op_DivI:
279 case Op_ModI:
280 case Op_UDivI:
281 case Op_UModI:
282 zero = TypeInt::ZERO;
283 break;
284 case Op_DivL:
285 case Op_ModL:
286 case Op_UDivL:
287 case Op_UModL:
288 zero = TypeLong::ZERO;
289 break;
290 default:
291 return false;
292 }
293
294 if (n->in(0) != nullptr) {
295 // Cannot split through phi if Div or Mod node has a control dependency to a zero check.
296 return true;
297 }
298
299 Node* divisor = n->in(2);
300 return is_divisor_loop_phi(divisor, region) &&
301 loop_phi_backedge_type_contains_zero(divisor, zero);
302 }
303
304 bool PhaseIdealLoop::is_divisor_loop_phi(const Node* divisor, const Node* loop) {
305 return loop->is_Loop() && divisor->is_Phi() && divisor->in(0) == loop;
306 }
307
308 bool PhaseIdealLoop::loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const {
309 return _igvn.type(phi_divisor->in(LoopNode::LoopBackControl))->filter_speculative(zero) != Type::TOP;
310 }
311
312 //------------------------------dominated_by------------------------------------
313 // Replace the dominated test with an obvious true or false. Place it on the
314 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
315 // live path up to the dominating control.
316 void PhaseIdealLoop::dominated_by(IfProjNode* prevdom, IfNode* iff, bool flip, bool pin_array_access_nodes) {
317 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
318
319 // prevdom is the dominating projection of the dominating test.
320 assert(iff->Opcode() == Op_If ||
321 iff->Opcode() == Op_CountedLoopEnd ||
322 iff->Opcode() == Op_LongCountedLoopEnd ||
323 iff->Opcode() == Op_RangeCheck ||
324 iff->Opcode() == Op_ParsePredicate,
325 "Check this code when new subtype is added");
326
327 int pop = prevdom->Opcode();
328 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
329 if (flip) {
330 if (pop == Op_IfTrue)
331 pop = Op_IfFalse;
332 else
333 pop = Op_IfTrue;
334 }
335 // 'con' is set to true or false to kill the dominated test.
336 Node* con = makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
337 // Hack the dominated test
338 _igvn.replace_input_of(iff, 1, con);
339
340 // If I don't have a reachable TRUE and FALSE path following the IfNode then
341 // I can assume this path reaches an infinite loop. In this case it's not
342 // important to optimize the data Nodes - either the whole compilation will
343 // be tossed or this path (and all data Nodes) will go dead.
344 if (iff->outcnt() != 2) {
345 return;
346 }
347
348 // Make control-dependent data Nodes on the live path (path that will remain
349 // once the dominated IF is removed) become control-dependent on the
350 // dominating projection.
351 Node* dp = iff->proj_out_or_null(pop == Op_IfTrue);
352
353 if (dp == nullptr) {
354 return;
355 }
356
357 rewire_safe_outputs_to_dominator(dp, prevdom, pin_array_access_nodes);
358 }
359
360 void PhaseIdealLoop::rewire_safe_outputs_to_dominator(Node* source, Node* dominator, const bool pin_array_access_nodes) {
361 IdealLoopTree* old_loop = get_loop(source);
362
363 for (DUIterator_Fast imax, i = source->fast_outs(imax); i < imax; i++) {
364 Node* out = source->fast_out(i); // Control-dependent node
365 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check.
366 if (out->depends_only_on_test() && _igvn.no_dependent_zero_check(out)) {
367 assert(out->in(0) == source, "must be control dependent on source");
368 _igvn.replace_input_of(out, 0, dominator);
369 if (pin_array_access_nodes) {
370 // Because of Loop Predication, Loads and range check Cast nodes that are control dependent on this range
371 // check (that is about to be removed) now depend on multiple dominating Hoisted Check Predicates. After the
372 // removal of this range check, these control dependent nodes end up at the lowest/nearest dominating predicate
373 // in the graph. To ensure that these Loads/Casts do not float above any of the dominating checks (even when the
374 // lowest dominating check is later replaced by yet another dominating check), we need to pin them at the lowest
375 // dominating check.
376 Node* clone = out->pin_array_access_node();
377 if (clone != nullptr) {
378 clone = _igvn.register_new_node_with_optimizer(clone, out);
379 _igvn.replace_node(out, clone);
380 out = clone;
381 }
382 }
383 set_early_ctrl(out, false);
384 IdealLoopTree* new_loop = get_loop(get_ctrl(out));
385 if (old_loop != new_loop) {
386 if (!old_loop->_child) {
387 old_loop->_body.yank(out);
388 }
389 if (!new_loop->_child) {
390 new_loop->_body.push(out);
391 }
392 }
393 --i;
394 --imax;
395 }
396 }
397 }
398
399 //------------------------------has_local_phi_input----------------------------
400 // Return TRUE if 'n' has Phi inputs from its local block and no other
401 // block-local inputs (all non-local-phi inputs come from earlier blocks)
402 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
403 Node *n_ctrl = get_ctrl(n);
404 // See if some inputs come from a Phi in this block, or from before
405 // this block.
406 uint i;
407 for( i = 1; i < n->req(); i++ ) {
408 Node *phi = n->in(i);
409 if( phi->is_Phi() && phi->in(0) == n_ctrl )
410 break;
411 }
412 if( i >= n->req() )
413 return nullptr; // No Phi inputs; nowhere to clone thru
414
415 // Check for inputs created between 'n' and the Phi input. These
416 // must split as well; they have already been given the chance
417 // (courtesy of a post-order visit) and since they did not we must
418 // recover the 'cost' of splitting them by being very profitable
419 // when splitting 'n'. Since this is unlikely we simply give up.
420 for( i = 1; i < n->req(); i++ ) {
421 Node *m = n->in(i);
422 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
423 // We allow the special case of AddP's with no local inputs.
424 // This allows us to split-up address expressions.
425 if (m->is_AddP() &&
426 get_ctrl(m->in(AddPNode::Base)) != n_ctrl &&
427 get_ctrl(m->in(AddPNode::Address)) != n_ctrl &&
428 get_ctrl(m->in(AddPNode::Offset)) != n_ctrl) {
429 // Move the AddP up to the dominating point. That's fine because control of m's inputs
430 // must dominate get_ctrl(m) == n_ctrl and we just checked that the input controls are != n_ctrl.
431 Node* c = find_non_split_ctrl(idom(n_ctrl));
432 if (c->is_OuterStripMinedLoop()) {
433 c->as_Loop()->verify_strip_mined(1);
434 c = c->in(LoopNode::EntryControl);
435 }
436 set_ctrl_and_loop(m, c);
437 continue;
438 }
439 return nullptr;
440 }
441 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
442 }
443
444 return n_ctrl;
445 }
446
447 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
448 Node* PhaseIdealLoop::remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt) {
449 assert(bt == T_INT || bt == T_LONG, "only for integers");
450 int n_op = n->Opcode();
451
452 if (n_op == Op_LShift(bt)) {
453 // Scale is loop invariant
454 Node* scale = n->in(2);
455 Node* scale_ctrl = get_ctrl(scale);
456 IdealLoopTree* scale_loop = get_loop(scale_ctrl);
457 if (n_loop == scale_loop || !scale_loop->is_member(n_loop)) {
458 return nullptr;
459 }
460 const TypeInt* scale_t = scale->bottom_type()->isa_int();
461 if (scale_t != nullptr && scale_t->is_con() && scale_t->get_con() >= 16) {
462 return nullptr; // Dont bother with byte/short masking
463 }
464 // Add must vary with loop (else shift would be loop-invariant)
465 Node* add = n->in(1);
466 Node* add_ctrl = get_ctrl(add);
467 IdealLoopTree* add_loop = get_loop(add_ctrl);
468 if (n_loop != add_loop) {
469 return nullptr; // happens w/ evil ZKM loops
470 }
471
472 // Convert I-V into I+ (0-V); same for V-I
473 if (add->Opcode() == Op_Sub(bt) &&
474 _igvn.type(add->in(1)) != TypeInteger::zero(bt)) {
475 assert(add->Opcode() == Op_SubI || add->Opcode() == Op_SubL, "");
476 Node* zero = integercon(0, bt);
477 Node* neg = SubNode::make(zero, add->in(2), bt);
478 register_new_node_with_ctrl_of(neg, add->in(2));
479 add = AddNode::make(add->in(1), neg, bt);
480 register_new_node(add, add_ctrl);
481 }
482 if (add->Opcode() != Op_Add(bt)) return nullptr;
483 assert(add->Opcode() == Op_AddI || add->Opcode() == Op_AddL, "");
484 // See if one add input is loop invariant
485 Node* add_var = add->in(1);
486 Node* add_var_ctrl = get_ctrl(add_var);
487 IdealLoopTree* add_var_loop = get_loop(add_var_ctrl);
488 Node* add_invar = add->in(2);
489 Node* add_invar_ctrl = get_ctrl(add_invar);
490 IdealLoopTree* add_invar_loop = get_loop(add_invar_ctrl);
491 if (add_invar_loop == n_loop) {
492 // Swap to find the invariant part
493 add_invar = add_var;
494 add_invar_ctrl = add_var_ctrl;
495 add_invar_loop = add_var_loop;
496 add_var = add->in(2);
497 } else if (add_var_loop != n_loop) { // Else neither input is loop invariant
498 return nullptr;
499 }
500 if (n_loop == add_invar_loop || !add_invar_loop->is_member(n_loop)) {
501 return nullptr; // No invariant part of the add?
502 }
503
504 // Yes! Reshape address expression!
505 Node* inv_scale = LShiftNode::make(add_invar, scale, bt);
506 Node* inv_scale_ctrl =
507 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
508 add_invar_ctrl : scale_ctrl;
509 register_new_node(inv_scale, inv_scale_ctrl);
510 Node* var_scale = LShiftNode::make(add_var, scale, bt);
511 register_new_node(var_scale, n_ctrl);
512 Node* var_add = AddNode::make(var_scale, inv_scale, bt);
513 register_new_node(var_add, n_ctrl);
514 _igvn.replace_node(n, var_add);
515 return var_add;
516 }
517 return nullptr;
518 }
519
520 //------------------------------remix_address_expressions----------------------
521 // Rework addressing expressions to get the most loop-invariant stuff
522 // moved out. We'd like to do all associative operators, but it's especially
523 // important (common) to do address expressions.
524 Node* PhaseIdealLoop::remix_address_expressions(Node* n) {
525 if (!has_ctrl(n)) return nullptr;
526 Node* n_ctrl = get_ctrl(n);
527 IdealLoopTree* n_loop = get_loop(n_ctrl);
528
529 // See if 'n' mixes loop-varying and loop-invariant inputs and
530 // itself is loop-varying.
531
532 // Only interested in binary ops (and AddP)
533 if (n->req() < 3 || n->req() > 4) return nullptr;
534
535 Node* n1_ctrl = get_ctrl(n->in( 1));
536 Node* n2_ctrl = get_ctrl(n->in( 2));
537 Node* n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
538 IdealLoopTree* n1_loop = get_loop(n1_ctrl);
539 IdealLoopTree* n2_loop = get_loop(n2_ctrl);
540 IdealLoopTree* n3_loop = get_loop(n3_ctrl);
541
542 // Does one of my inputs spin in a tighter loop than self?
543 if ((n_loop->is_member(n1_loop) && n_loop != n1_loop) ||
544 (n_loop->is_member(n2_loop) && n_loop != n2_loop) ||
545 (n_loop->is_member(n3_loop) && n_loop != n3_loop)) {
546 return nullptr; // Leave well enough alone
547 }
548
549 // Is at least one of my inputs loop-invariant?
550 if (n1_loop == n_loop &&
551 n2_loop == n_loop &&
552 n3_loop == n_loop) {
553 return nullptr; // No loop-invariant inputs
554 }
555
556 Node* res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_INT);
557 if (res != nullptr) {
558 return res;
559 }
560 res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_LONG);
561 if (res != nullptr) {
562 return res;
563 }
564
565 int n_op = n->Opcode();
566 // Replace (I+V) with (V+I)
567 if (n_op == Op_AddI ||
568 n_op == Op_AddL ||
569 n_op == Op_AddF ||
570 n_op == Op_AddD ||
571 n_op == Op_MulI ||
572 n_op == Op_MulL ||
573 n_op == Op_MulF ||
574 n_op == Op_MulD) {
575 if (n2_loop == n_loop) {
576 assert(n1_loop != n_loop, "");
577 n->swap_edges(1, 2);
578 }
579 }
580
581 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
582 // but not if I2 is a constant. Skip for irreducible loops.
583 if (n_op == Op_AddP && n_loop->_head->is_Loop()) {
584 if (n2_loop == n_loop && n3_loop != n_loop) {
585 if (n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con()) {
586 Node* n22_ctrl = get_ctrl(n->in(2)->in(2));
587 Node* n23_ctrl = get_ctrl(n->in(2)->in(3));
588 IdealLoopTree* n22loop = get_loop(n22_ctrl);
589 IdealLoopTree* n23_loop = get_loop(n23_ctrl);
590 if (n22loop != n_loop && n22loop->is_member(n_loop) &&
591 n23_loop == n_loop) {
592 Node* add1 = new AddPNode(n->in(1), n->in(2)->in(2), n->in(3));
593 // Stuff new AddP in the loop preheader
594 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
595 Node* add2 = new AddPNode(n->in(1), add1, n->in(2)->in(3));
596 register_new_node(add2, n_ctrl);
597 _igvn.replace_node(n, add2);
598 return add2;
599 }
600 }
601 }
602
603 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
604 if (n2_loop != n_loop && n3_loop == n_loop) {
605 if (n->in(3)->Opcode() == Op_AddX) {
606 Node* V = n->in(3)->in(1);
607 Node* I = n->in(3)->in(2);
608 if (is_member(n_loop,get_ctrl(V))) {
609 } else {
610 Node *tmp = V; V = I; I = tmp;
611 }
612 if (!is_member(n_loop,get_ctrl(I))) {
613 Node* add1 = new AddPNode(n->in(1), n->in(2), I);
614 // Stuff new AddP in the loop preheader
615 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
616 Node* add2 = new AddPNode(n->in(1), add1, V);
617 register_new_node(add2, n_ctrl);
618 _igvn.replace_node(n, add2);
619 return add2;
620 }
621 }
622 }
623 }
624
625 return nullptr;
626 }
627
628 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1]))
629 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) {
630 assert(n->Opcode() == Op_AddI, "sanity");
631 Node * nn = nullptr;
632 Node * in1 = n->in(1);
633 Node * in2 = n->in(2);
634 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) {
635 IdealLoopTree* loop_n = get_loop(get_ctrl(n));
636 if (loop_n->is_counted() &&
637 loop_n->_head->as_Loop()->is_valid_counted_loop(T_INT) &&
638 Matcher::match_rule_supported(Op_MulAddVS2VI) &&
639 Matcher::match_rule_supported(Op_MulAddS2I)) {
640 Node* mul_in1 = in1->in(1);
641 Node* mul_in2 = in1->in(2);
642 Node* mul_in3 = in2->in(1);
643 Node* mul_in4 = in2->in(2);
644 if (mul_in1->Opcode() == Op_LoadS &&
645 mul_in2->Opcode() == Op_LoadS &&
646 mul_in3->Opcode() == Op_LoadS &&
647 mul_in4->Opcode() == Op_LoadS) {
648 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1));
649 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2));
650 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3));
651 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4));
652 IdealLoopTree* loop5 = get_loop(get_ctrl(in1));
653 IdealLoopTree* loop6 = get_loop(get_ctrl(in2));
654 // All nodes should be in the same counted loop.
655 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 &&
656 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) {
657 Node* adr1 = mul_in1->in(MemNode::Address);
658 Node* adr2 = mul_in2->in(MemNode::Address);
659 Node* adr3 = mul_in3->in(MemNode::Address);
660 Node* adr4 = mul_in4->in(MemNode::Address);
661 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) {
662 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) &&
663 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) {
664 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4);
665 register_new_node_with_ctrl_of(nn, n);
666 _igvn.replace_node(n, nn);
667 return nn;
668 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) &&
669 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) {
670 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3);
671 register_new_node_with_ctrl_of(nn, n);
672 _igvn.replace_node(n, nn);
673 return nn;
674 }
675 }
676 }
677 }
678 }
679 }
680 return nn;
681 }
682
683 //------------------------------conditional_move-------------------------------
684 // Attempt to replace a Phi with a conditional move. We have some pretty
685 // strict profitability requirements. All Phis at the merge point must
686 // be converted, so we can remove the control flow. We need to limit the
687 // number of c-moves to a small handful. All code that was in the side-arms
688 // of the CFG diamond is now speculatively executed. This code has to be
689 // "cheap enough". We are pretty much limited to CFG diamonds that merge
690 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
691 Node *PhaseIdealLoop::conditional_move( Node *region ) {
692
693 assert(region->is_Region(), "sanity check");
694 if (region->req() != 3) return nullptr;
695
696 // Check for CFG diamond
697 Node *lp = region->in(1);
698 Node *rp = region->in(2);
699 if (!lp || !rp) return nullptr;
700 Node *lp_c = lp->in(0);
701 if (lp_c == nullptr || lp_c != rp->in(0) || !lp_c->is_If()) return nullptr;
702 IfNode *iff = lp_c->as_If();
703
704 // Check for ops pinned in an arm of the diamond.
705 // Can't remove the control flow in this case
706 if (lp->outcnt() > 1) return nullptr;
707 if (rp->outcnt() > 1) return nullptr;
708
709 IdealLoopTree* r_loop = get_loop(region);
710 assert(r_loop == get_loop(iff), "sanity");
711 // Always convert to CMOVE if all results are used only outside this loop.
712 bool used_inside_loop = (r_loop == _ltree_root);
713
714 // Check profitability
715 int cost = 0;
716 int phis = 0;
717 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
718 Node *out = region->fast_out(i);
719 if (!out->is_Phi()) continue; // Ignore other control edges, etc
720 phis++;
721 PhiNode* phi = out->as_Phi();
722 BasicType bt = phi->type()->basic_type();
723 switch (bt) {
724 case T_DOUBLE:
725 case T_FLOAT:
726 if (C->use_cmove()) {
727 continue; //TODO: maybe we want to add some cost
728 }
729 cost += Matcher::float_cmove_cost(); // Could be very expensive
730 break;
731 case T_LONG: {
732 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
733 }
734 case T_INT: // These all CMOV fine
735 case T_ADDRESS: { // (RawPtr)
736 cost++;
737 break;
738 }
739 case T_NARROWOOP: // Fall through
740 case T_OBJECT: { // Base oops are OK, but not derived oops
741 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
742 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
743 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
744 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
745 // have a Phi for the base here that we convert to a CMOVE all is well
746 // and good. But if the base is dead, we'll not make a CMOVE. Later
747 // the allocator will have to produce a base by creating a CMOVE of the
748 // relevant bases. This puts the allocator in the business of
749 // manufacturing expensive instructions, generally a bad plan.
750 // Just Say No to Conditionally-Moved Derived Pointers.
751 if (tp && tp->offset() != 0)
752 return nullptr;
753 cost++;
754 break;
755 }
756 default:
757 return nullptr; // In particular, can't do memory or I/O
758 }
759 // Add in cost any speculative ops
760 for (uint j = 1; j < region->req(); j++) {
761 Node *proj = region->in(j);
762 Node *inp = phi->in(j);
763 if (get_ctrl(inp) == proj) { // Found local op
764 cost++;
765 // Check for a chain of dependent ops; these will all become
766 // speculative in a CMOV.
767 for (uint k = 1; k < inp->req(); k++)
768 if (get_ctrl(inp->in(k)) == proj)
769 cost += ConditionalMoveLimit; // Too much speculative goo
770 }
771 }
772 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
773 // This will likely Split-If, a higher-payoff operation.
774 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
775 Node* use = phi->fast_out(k);
776 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
777 cost += ConditionalMoveLimit;
778 // Is there a use inside the loop?
779 // Note: check only basic types since CMoveP is pinned.
780 if (!used_inside_loop && is_java_primitive(bt)) {
781 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
782 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
783 used_inside_loop = true;
784 }
785 }
786 }
787 }//for
788 Node* bol = iff->in(1);
789 assert(!bol->is_OpaqueInitializedAssertionPredicate(), "Initialized Assertion Predicates cannot form a diamond with Halt");
790 if (bol->is_OpaqueTemplateAssertionPredicate()) {
791 // Ignore Template Assertion Predicates with OpaqueTemplateAssertionPredicate nodes.
792 return nullptr;
793 }
794 if (bol->is_OpaqueMultiversioning()) {
795 assert(bol->as_OpaqueMultiversioning()->is_useless(), "Must be useless, i.e. fast main loop has already disappeared.");
796 // Ignore multiversion_if that just lost its loops. The OpaqueMultiversioning is marked useless,
797 // and will make the multiversion_if constant fold in the next IGVN round.
798 return nullptr;
799 }
800 if (!bol->is_Bool()) {
801 assert(false, "Expected Bool, but got %s", NodeClassNames[bol->Opcode()]);
802 return nullptr;
803 }
804 int cmp_op = bol->in(1)->Opcode();
805 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode
806 return nullptr;
807 }
808 // It is expensive to generate flags from a float compare.
809 // Avoid duplicated float compare.
810 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return nullptr;
811
812 float infrequent_prob = PROB_UNLIKELY_MAG(3);
813 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
814 if (used_inside_loop) {
815 if (cost >= ConditionalMoveLimit) return nullptr; // Too much goo
816
817 // BlockLayoutByFrequency optimization moves infrequent branch
818 // from hot path. No point in CMOV'ing in such case (110 is used
819 // instead of 100 to take into account not exactness of float value).
820 if (BlockLayoutByFrequency) {
821 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
822 }
823 }
824 // Check for highly predictable branch. No point in CMOV'ing if
825 // we are going to predict accurately all the time.
826 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
827 //keep going
828 } else if (iff->_prob < infrequent_prob ||
829 iff->_prob > (1.0f - infrequent_prob))
830 return nullptr;
831
832 // --------------
833 // Now replace all Phis with CMOV's
834 Node *cmov_ctrl = iff->in(0);
835 uint flip = (lp->Opcode() == Op_IfTrue);
836 Node_List wq;
837 while (1) {
838 PhiNode* phi = nullptr;
839 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
840 Node *out = region->fast_out(i);
841 if (out->is_Phi()) {
842 phi = out->as_Phi();
843 break;
844 }
845 }
846 if (phi == nullptr || _igvn.type(phi) == Type::TOP || !CMoveNode::supported(_igvn.type(phi))) {
847 break;
848 }
849 // Move speculative ops
850 wq.push(phi);
851 while (wq.size() > 0) {
852 Node *n = wq.pop();
853 for (uint j = 1; j < n->req(); j++) {
854 Node* m = n->in(j);
855 if (m != nullptr && !is_dominator(get_ctrl(m), cmov_ctrl)) {
856 set_ctrl(m, cmov_ctrl);
857 wq.push(m);
858 }
859 }
860 }
861 Node* cmov = CMoveNode::make(iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
862 register_new_node(cmov, cmov_ctrl);
863 _igvn.replace_node(phi, cmov);
864 #ifndef PRODUCT
865 if (TraceLoopOpts) {
866 tty->print("CMOV ");
867 r_loop->dump_head();
868 if (Verbose) {
869 bol->in(1)->dump(1);
870 cmov->dump(1);
871 }
872 }
873 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
874 #endif
875 }
876
877 // The useless CFG diamond will fold up later; see the optimization in
878 // RegionNode::Ideal.
879 _igvn._worklist.push(region);
880
881 return iff->in(1);
882 }
883
884 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
885 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
886 Node* u = m->fast_out(i);
887 if (u->is_CFG()) {
888 if (u->is_NeverBranch()) {
889 u = u->as_NeverBranch()->proj_out(0);
890 enqueue_cfg_uses(u, wq);
891 } else {
892 wq.push(u);
893 }
894 }
895 }
896 }
897
898 // Try moving a store out of a loop, right before the loop
899 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
900 // Store has to be first in the loop body
901 IdealLoopTree *n_loop = get_loop(n_ctrl);
902 if (n->is_Store() && n_loop != _ltree_root &&
903 n_loop->is_loop() && n_loop->_head->is_Loop() &&
904 n->in(0) != nullptr) {
905 Node* address = n->in(MemNode::Address);
906 Node* value = n->in(MemNode::ValueIn);
907 Node* mem = n->in(MemNode::Memory);
908 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
909 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
910
911 // - address and value must be loop invariant
912 // - memory must be a memory Phi for the loop
913 // - Store must be the only store on this memory slice in the
914 // loop: if there's another store following this one then value
915 // written at iteration i by the second store could be overwritten
916 // at iteration i+n by the first store: it's not safe to move the
917 // first store out of the loop
918 // - nothing must observe the memory Phi: it guarantees no read
919 // before the store, we are also guaranteed the store post
920 // dominates the loop head (ignoring a possible early
921 // exit). Otherwise there would be extra Phi involved between the
922 // loop's Phi and the store.
923 // - there must be no early exit from the loop before the Store
924 // (such an exit most of the time would be an extra use of the
925 // memory Phi but sometimes is a bottom memory Phi that takes the
926 // store as input).
927
928 if (!n_loop->is_member(address_loop) &&
929 !n_loop->is_member(value_loop) &&
930 mem->is_Phi() && mem->in(0) == n_loop->_head &&
931 mem->outcnt() == 1 &&
932 mem->in(LoopNode::LoopBackControl) == n) {
933
934 assert(n_loop->_tail != nullptr, "need a tail");
935 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
936
937 // Verify that there's no early exit of the loop before the store.
938 bool ctrl_ok = false;
939 {
940 // Follow control from loop head until n, we exit the loop or
941 // we reach the tail
942 ResourceMark rm;
943 Unique_Node_List wq;
944 wq.push(n_loop->_head);
945
946 for (uint next = 0; next < wq.size(); ++next) {
947 Node *m = wq.at(next);
948 if (m == n->in(0)) {
949 ctrl_ok = true;
950 continue;
951 }
952 assert(!has_ctrl(m), "should be CFG");
953 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
954 ctrl_ok = false;
955 break;
956 }
957 enqueue_cfg_uses(m, wq);
958 if (wq.size() > 10) {
959 ctrl_ok = false;
960 break;
961 }
962 }
963 }
964 if (ctrl_ok) {
965 // move the Store
966 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
967 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
968 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
969 // Disconnect the phi now. An empty phi can confuse other
970 // optimizations in this pass of loop opts.
971 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
972 n_loop->_body.yank(mem);
973
974 set_ctrl_and_loop(n, n->in(0));
975
976 return n;
977 }
978 }
979 }
980 return nullptr;
981 }
982
983 // Try moving a store out of a loop, right after the loop
984 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
985 if (n->is_Store() && n->in(0) != nullptr) {
986 Node *n_ctrl = get_ctrl(n);
987 IdealLoopTree *n_loop = get_loop(n_ctrl);
988 // Store must be in a loop
989 if (n_loop != _ltree_root && !n_loop->_irreducible) {
990 Node* address = n->in(MemNode::Address);
991 Node* value = n->in(MemNode::ValueIn);
992 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
993 // address must be loop invariant
994 if (!n_loop->is_member(address_loop)) {
995 // Store must be last on this memory slice in the loop and
996 // nothing in the loop must observe it
997 Node* phi = nullptr;
998 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
999 Node* u = n->fast_out(i);
1000 if (has_ctrl(u)) { // control use?
1001 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
1002 if (!n_loop->is_member(u_loop)) {
1003 continue;
1004 }
1005 if (u->is_Phi() && u->in(0) == n_loop->_head) {
1006 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
1007 // multiple phis on the same slice are possible
1008 if (phi != nullptr) {
1009 return;
1010 }
1011 phi = u;
1012 continue;
1013 }
1014 }
1015 return;
1016 }
1017 if (phi != nullptr) {
1018 // Nothing in the loop before the store (next iteration)
1019 // must observe the stored value
1020 bool mem_ok = true;
1021 {
1022 ResourceMark rm;
1023 Unique_Node_List wq;
1024 wq.push(phi);
1025 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
1026 Node *m = wq.at(next);
1027 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
1028 Node* u = m->fast_out(i);
1029 if (u->is_Store() || u->is_Phi()) {
1030 if (u != n) {
1031 wq.push(u);
1032 mem_ok = (wq.size() <= 10);
1033 }
1034 } else {
1035 mem_ok = false;
1036 break;
1037 }
1038 }
1039 }
1040 }
1041 if (mem_ok) {
1042 // Move the store out of the loop if the LCA of all
1043 // users (except for the phi) is outside the loop.
1044 Node* hook = new Node(1);
1045 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead
1046 _igvn.rehash_node_delayed(phi);
1047 int count = phi->replace_edge(n, hook, &_igvn);
1048 assert(count > 0, "inconsistent phi");
1049
1050 // Compute latest point this store can go
1051 Node* lca = get_late_ctrl(n, get_ctrl(n));
1052 if (lca->is_OuterStripMinedLoop()) {
1053 lca = lca->in(LoopNode::EntryControl);
1054 }
1055 if (n_loop->is_member(get_loop(lca))) {
1056 // LCA is in the loop - bail out
1057 _igvn.replace_node(hook, n);
1058 return;
1059 }
1060 #ifdef ASSERT
1061 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
1062 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
1063 n_loop->_head->as_Loop()->verify_strip_mined(1);
1064 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
1065 IdealLoopTree* outer_loop = get_loop(outer);
1066 assert(n_loop->_parent == outer_loop, "broken loop tree");
1067 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
1068 }
1069 #endif
1070 lca = place_outside_loop(lca, n_loop);
1071 assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop");
1072 assert(get_loop(lca)->_nest < n_loop->_nest || get_loop(lca)->_head->as_Loop()->is_in_infinite_subgraph(), "must not be moved into inner loop");
1073
1074 // Move store out of the loop
1075 _igvn.replace_node(hook, n->in(MemNode::Memory));
1076 _igvn.replace_input_of(n, 0, lca);
1077 set_ctrl_and_loop(n, lca);
1078
1079 // Disconnect the phi now. An empty phi can confuse other
1080 // optimizations in this pass of loop opts..
1081 if (phi->in(LoopNode::LoopBackControl) == phi) {
1082 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
1083 n_loop->_body.yank(phi);
1084 }
1085 }
1086 }
1087 }
1088 }
1089 }
1090 }
1091
1092 //------------------------------split_if_with_blocks_pre-----------------------
1093 // Do the real work in a non-recursive function. Data nodes want to be
1094 // cloned in the pre-order so they can feed each other nicely.
1095 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
1096 // Cloning these guys is unlikely to win
1097 int n_op = n->Opcode();
1098 if (n_op == Op_MergeMem) {
1099 return n;
1100 }
1101 if (n->is_Proj()) {
1102 return n;
1103 }
1104 // Do not clone-up CmpFXXX variations, as these are always
1105 // followed by a CmpI
1106 if (n->is_Cmp()) {
1107 return n;
1108 }
1109 // Attempt to use a conditional move instead of a phi/branch
1110 if (ConditionalMoveLimit > 0 && n_op == Op_Region) {
1111 Node *cmov = conditional_move( n );
1112 if (cmov) {
1113 return cmov;
1114 }
1115 }
1116 if (n->is_CFG() || n->is_LoadStore()) {
1117 return n;
1118 }
1119 if (n->is_Opaque1()) { // Opaque nodes cannot be mod'd
1120 if (!C->major_progress()) { // If chance of no more loop opts...
1121 _igvn._worklist.push(n); // maybe we'll remove them
1122 }
1123 return n;
1124 }
1125
1126 if (n->is_Con()) {
1127 return n; // No cloning for Con nodes
1128 }
1129
1130 Node *n_ctrl = get_ctrl(n);
1131 if (!n_ctrl) {
1132 return n; // Dead node
1133 }
1134
1135 Node* res = try_move_store_before_loop(n, n_ctrl);
1136 if (res != nullptr) {
1137 return n;
1138 }
1139
1140 // Attempt to remix address expressions for loop invariants
1141 Node *m = remix_address_expressions( n );
1142 if( m ) return m;
1143
1144 if (n_op == Op_AddI) {
1145 Node *nn = convert_add_to_muladd( n );
1146 if ( nn ) return nn;
1147 }
1148
1149 if (n->is_ConstraintCast()) {
1150 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
1151 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
1152 // Node control inputs don't necessarily agree with loop control info (due to
1153 // transformations happened in between), thus additional dominance check is needed
1154 // to keep loop info valid.
1155 if (dom_cast != nullptr && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
1156 _igvn.replace_node(n, dom_cast);
1157 return dom_cast;
1158 }
1159 }
1160
1161 // Determine if the Node has inputs from some local Phi.
1162 // Returns the block to clone thru.
1163 Node *n_blk = has_local_phi_input( n );
1164 if( !n_blk ) return n;
1165
1166 // Do not clone the trip counter through on a CountedLoop
1167 // (messes up the canonical shape).
1168 if (((n_blk->is_CountedLoop() || (n_blk->is_Loop() && n_blk->as_Loop()->is_loop_nest_inner_loop())) && n->Opcode() == Op_AddI) ||
1169 (n_blk->is_LongCountedLoop() && n->Opcode() == Op_AddL)) {
1170 return n;
1171 }
1172 // Pushing a shift through the iv Phi can get in the way of addressing optimizations or range check elimination
1173 if (n_blk->is_BaseCountedLoop() && n->Opcode() == Op_LShift(n_blk->as_BaseCountedLoop()->bt()) &&
1174 n->in(1) == n_blk->as_BaseCountedLoop()->phi()) {
1175 return n;
1176 }
1177
1178 // Check for having no control input; not pinned. Allow
1179 // dominating control.
1180 if (n->in(0)) {
1181 Node *dom = idom(n_blk);
1182 if (dom_lca(n->in(0), dom) != n->in(0)) {
1183 return n;
1184 }
1185 }
1186 // Policy: when is it profitable. You must get more wins than
1187 // policy before it is considered profitable. Policy is usually 0,
1188 // so 1 win is considered profitable. Big merges will require big
1189 // cloning, so get a larger policy.
1190 int policy = n_blk->req() >> 2;
1191
1192 // If the loop is a candidate for range check elimination,
1193 // delay splitting through it's phi until a later loop optimization
1194 if (n_blk->is_BaseCountedLoop()) {
1195 IdealLoopTree *lp = get_loop(n_blk);
1196 if (lp && lp->_rce_candidate) {
1197 return n;
1198 }
1199 }
1200
1201 if (must_throttle_split_if()) return n;
1202
1203 // Split 'n' through the merge point if it is profitable
1204 Node *phi = split_thru_phi( n, n_blk, policy );
1205 if (!phi) return n;
1206
1207 // Found a Phi to split thru!
1208 // Replace 'n' with the new phi
1209 _igvn.replace_node( n, phi );
1210 // Moved a load around the loop, 'en-registering' something.
1211 if (n_blk->is_Loop() && n->is_Load() &&
1212 !phi->in(LoopNode::LoopBackControl)->is_Load())
1213 C->set_major_progress();
1214
1215 return phi;
1216 }
1217
1218 static bool merge_point_too_heavy(Compile* C, Node* region) {
1219 // Bail out if the region and its phis have too many users.
1220 int weight = 0;
1221 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1222 weight += region->fast_out(i)->outcnt();
1223 }
1224 int nodes_left = C->max_node_limit() - C->live_nodes();
1225 if (weight * 8 > nodes_left) {
1226 if (PrintOpto) {
1227 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
1228 }
1229 return true;
1230 } else {
1231 return false;
1232 }
1233 }
1234
1235 static bool merge_point_safe(Node* region) {
1236 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1237 // having a PhiNode input. This sidesteps the dangerous case where the split
1238 // ConvI2LNode may become TOP if the input Value() does not
1239 // overlap the ConvI2L range, leaving a node which may not dominate its
1240 // uses.
1241 // A better fix for this problem can be found in the BugTraq entry, but
1242 // expediency for Mantis demands this hack.
1243 #ifdef _LP64
1244 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1245 Node* n = region->fast_out(i);
1246 if (n->is_Phi()) {
1247 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1248 Node* m = n->fast_out(j);
1249 if (m->Opcode() == Op_ConvI2L)
1250 return false;
1251 if (m->is_CastII()) {
1252 return false;
1253 }
1254 }
1255 }
1256 }
1257 #endif
1258 return true;
1259 }
1260
1261
1262 //------------------------------place_outside_loop---------------------------------
1263 // Place some computation outside of this loop on the path to the use passed as argument
1264 Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) const {
1265 Node* head = loop->_head;
1266 assert(!loop->is_member(get_loop(useblock)), "must be outside loop");
1267 if (head->is_Loop() && head->as_Loop()->is_strip_mined()) {
1268 loop = loop->_parent;
1269 assert(loop->_head->is_OuterStripMinedLoop(), "malformed strip mined loop");
1270 }
1271
1272 // Pick control right outside the loop
1273 for (;;) {
1274 Node* dom = idom(useblock);
1275 if (loop->is_member(get_loop(dom))) {
1276 break;
1277 }
1278 useblock = dom;
1279 }
1280 assert(find_non_split_ctrl(useblock) == useblock, "should be non split control");
1281 return useblock;
1282 }
1283
1284
1285 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1286 if (!n->is_If() || n->is_BaseCountedLoopEnd()) {
1287 return false;
1288 }
1289 if (!n->in(0)->is_Region()) {
1290 return false;
1291 }
1292
1293 Node* region = n->in(0);
1294 Node* dom = idom(region);
1295 if (!dom->is_If() || !n->as_If()->same_condition(dom, &_igvn)) {
1296 return false;
1297 }
1298 IfNode* dom_if = dom->as_If();
1299 Node* proj_true = dom_if->proj_out(1);
1300 Node* proj_false = dom_if->proj_out(0);
1301
1302 for (uint i = 1; i < region->req(); i++) {
1303 if (is_dominator(proj_true, region->in(i))) {
1304 continue;
1305 }
1306 if (is_dominator(proj_false, region->in(i))) {
1307 continue;
1308 }
1309 return false;
1310 }
1311
1312 return true;
1313 }
1314
1315
1316 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) {
1317 if (must_throttle_split_if()) {
1318 return false;
1319 }
1320
1321 // Do not do 'split-if' if irreducible loops are present.
1322 if (_has_irreducible_loops) {
1323 return false;
1324 }
1325
1326 if (merge_point_too_heavy(C, n_ctrl)) {
1327 return false;
1328 }
1329
1330 // Do not do 'split-if' if some paths are dead. First do dead code
1331 // elimination and then see if its still profitable.
1332 for (uint i = 1; i < n_ctrl->req(); i++) {
1333 if (n_ctrl->in(i) == C->top()) {
1334 return false;
1335 }
1336 }
1337
1338 // If trying to do a 'Split-If' at the loop head, it is only
1339 // profitable if the cmp folds up on BOTH paths. Otherwise we
1340 // risk peeling a loop forever.
1341
1342 // CNC - Disabled for now. Requires careful handling of loop
1343 // body selection for the cloned code. Also, make sure we check
1344 // for any input path not being in the same loop as n_ctrl. For
1345 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1346 // because the alternative loop entry points won't be converted
1347 // into LoopNodes.
1348 IdealLoopTree *n_loop = get_loop(n_ctrl);
1349 for (uint j = 1; j < n_ctrl->req(); j++) {
1350 if (get_loop(n_ctrl->in(j)) != n_loop) {
1351 return false;
1352 }
1353 }
1354
1355 // Check for safety of the merge point.
1356 if (!merge_point_safe(n_ctrl)) {
1357 return false;
1358 }
1359
1360 return true;
1361 }
1362
1363 // Detect if the node is the inner strip-mined loop
1364 // Return: null if it's not the case, or the exit of outer strip-mined loop
1365 static Node* is_inner_of_stripmined_loop(const Node* out) {
1366 Node* out_le = nullptr;
1367
1368 if (out->is_CountedLoopEnd()) {
1369 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode();
1370
1371 if (loop != nullptr && loop->is_strip_mined()) {
1372 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit();
1373 }
1374 }
1375
1376 return out_le;
1377 }
1378
1379 //------------------------------split_if_with_blocks_post----------------------
1380 // Do the real work in a non-recursive function. CFG hackery wants to be
1381 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1382 // info.
1383 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1384
1385 // Cloning Cmp through Phi's involves the split-if transform.
1386 // FastLock is not used by an If
1387 if (n->is_Cmp() && !n->is_FastLock()) {
1388 Node *n_ctrl = get_ctrl(n);
1389 // Determine if the Node has inputs from some local Phi.
1390 // Returns the block to clone thru.
1391 Node *n_blk = has_local_phi_input(n);
1392 if (n_blk != n_ctrl) {
1393 return;
1394 }
1395
1396 if (!can_split_if(n_ctrl)) {
1397 return;
1398 }
1399
1400 if (n->outcnt() != 1) {
1401 return; // Multiple bool's from 1 compare?
1402 }
1403 Node *bol = n->unique_out();
1404 assert(bol->is_Bool(), "expect a bool here");
1405 if (bol->outcnt() != 1) {
1406 return;// Multiple branches from 1 compare?
1407 }
1408 Node *iff = bol->unique_out();
1409
1410 // Check some safety conditions
1411 if (iff->is_If()) { // Classic split-if?
1412 if (iff->in(0) != n_ctrl) {
1413 return; // Compare must be in same blk as if
1414 }
1415 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1416 // Can't split CMove with different control.
1417 if (get_ctrl(iff) != n_ctrl) {
1418 return;
1419 }
1420 if (get_ctrl(iff->in(2)) == n_ctrl ||
1421 get_ctrl(iff->in(3)) == n_ctrl) {
1422 return; // Inputs not yet split-up
1423 }
1424 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1425 return; // Loop-invar test gates loop-varying CMOVE
1426 }
1427 } else {
1428 return; // some other kind of node, such as an Allocate
1429 }
1430
1431 // When is split-if profitable? Every 'win' on means some control flow
1432 // goes dead, so it's almost always a win.
1433 int policy = 0;
1434 // Split compare 'n' through the merge point if it is profitable
1435 Node *phi = split_thru_phi( n, n_ctrl, policy);
1436 if (!phi) {
1437 return;
1438 }
1439
1440 // Found a Phi to split thru!
1441 // Replace 'n' with the new phi
1442 _igvn.replace_node(n, phi);
1443
1444 // Now split the bool up thru the phi
1445 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1446 guarantee(bolphi != nullptr, "null boolean phi node");
1447
1448 _igvn.replace_node(bol, bolphi);
1449 assert(iff->in(1) == bolphi, "");
1450
1451 if (bolphi->Value(&_igvn)->singleton()) {
1452 return;
1453 }
1454
1455 // Conditional-move? Must split up now
1456 if (!iff->is_If()) {
1457 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1458 _igvn.replace_node(iff, cmovphi);
1459 return;
1460 }
1461
1462 // Now split the IF
1463 C->print_method(PHASE_BEFORE_SPLIT_IF, 4, iff);
1464 if (TraceLoopOpts) {
1465 tty->print_cr("Split-If");
1466 }
1467 do_split_if(iff);
1468 C->print_method(PHASE_AFTER_SPLIT_IF, 4, iff);
1469 return;
1470 }
1471
1472 // Two identical ifs back to back can be merged
1473 if (try_merge_identical_ifs(n)) {
1474 return;
1475 }
1476
1477 // Check for an IF ready to split; one that has its
1478 // condition codes input coming from a Phi at the block start.
1479 int n_op = n->Opcode();
1480
1481 // Check for an IF being dominated by another IF same test
1482 if (n_op == Op_If ||
1483 n_op == Op_RangeCheck) {
1484 Node *bol = n->in(1);
1485 uint max = bol->outcnt();
1486 // Check for same test used more than once?
1487 if (bol->is_Bool() && (max > 1 || bol->in(1)->is_SubTypeCheck())) {
1488 // Search up IDOMs to see if this IF is dominated.
1489 Node* cmp = bol->in(1);
1490 Node *cutoff = cmp->is_SubTypeCheck() ? dom_lca(get_ctrl(cmp->in(1)), get_ctrl(cmp->in(2))) : get_ctrl(bol);
1491
1492 // Now search up IDOMs till cutoff, looking for a dominating test
1493 Node *prevdom = n;
1494 Node *dom = idom(prevdom);
1495 while (dom != cutoff) {
1496 if (dom->req() > 1 && n->as_If()->same_condition(dom, &_igvn) && prevdom->in(0) == dom &&
1497 safe_for_if_replacement(dom)) {
1498 // It's invalid to move control dependent data nodes in the inner
1499 // strip-mined loop, because:
1500 // 1) break validation of LoopNode::verify_strip_mined()
1501 // 2) move code with side-effect in strip-mined loop
1502 // Move to the exit of outer strip-mined loop in that case.
1503 Node* out_le = is_inner_of_stripmined_loop(dom);
1504 if (out_le != nullptr) {
1505 prevdom = out_le;
1506 }
1507 // Replace the dominated test with an obvious true or false.
1508 // Place it on the IGVN worklist for later cleanup.
1509 C->set_major_progress();
1510 // Split if: pin array accesses that are control dependent on a range check and moved to a regular if,
1511 // to prevent an array load from floating above its range check. There are three cases:
1512 // 1. Move from RangeCheck "a" to RangeCheck "b": don't need to pin. If we ever remove b, then we pin
1513 // all its array accesses at that point.
1514 // 2. We move from RangeCheck "a" to regular if "b": need to pin. If we ever remove b, then its array
1515 // accesses would start to float, since we don't pin at that point.
1516 // 3. If we move from regular if: don't pin. All array accesses are already assumed to be pinned.
1517 bool pin_array_access_nodes = n->Opcode() == Op_RangeCheck &&
1518 prevdom->in(0)->Opcode() != Op_RangeCheck;
1519 dominated_by(prevdom->as_IfProj(), n->as_If(), false, pin_array_access_nodes);
1520 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
1521 return;
1522 }
1523 prevdom = dom;
1524 dom = idom(prevdom);
1525 }
1526 }
1527 }
1528
1529 try_sink_out_of_loop(n);
1530 if (C->failing()) {
1531 return;
1532 }
1533
1534 try_move_store_after_loop(n);
1535 }
1536
1537 // Transform:
1538 //
1539 // if (some_condition) {
1540 // // body 1
1541 // } else {
1542 // // body 2
1543 // }
1544 // if (some_condition) {
1545 // // body 3
1546 // } else {
1547 // // body 4
1548 // }
1549 //
1550 // into:
1551 //
1552 //
1553 // if (some_condition) {
1554 // // body 1
1555 // // body 3
1556 // } else {
1557 // // body 2
1558 // // body 4
1559 // }
1560 bool PhaseIdealLoop::try_merge_identical_ifs(Node* n) {
1561 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1562 Node *n_ctrl = n->in(0);
1563 IfNode* dom_if = idom(n_ctrl)->as_If();
1564 if (n->in(1) != dom_if->in(1)) {
1565 assert(n->in(1)->in(1)->is_SubTypeCheck() &&
1566 (n->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr ||
1567 dom_if->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr), "only for subtype checks with profile data attached");
1568 _igvn.replace_input_of(n, 1, dom_if->in(1));
1569 }
1570 ProjNode* dom_proj_true = dom_if->proj_out(1);
1571 ProjNode* dom_proj_false = dom_if->proj_out(0);
1572
1573 // Now split the IF
1574 RegionNode* new_false_region;
1575 RegionNode* new_true_region;
1576 do_split_if(n, &new_false_region, &new_true_region);
1577 assert(new_false_region->req() == new_true_region->req(), "");
1578 #ifdef ASSERT
1579 for (uint i = 1; i < new_false_region->req(); ++i) {
1580 assert(new_false_region->in(i)->in(0) == new_true_region->in(i)->in(0), "unexpected shape following split if");
1581 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");
1582 }
1583 #endif
1584 assert(new_false_region->in(1)->in(0)->in(1) == dom_if->in(1), "dominating if and dominated if after split must share test");
1585
1586 // We now have:
1587 // if (some_condition) {
1588 // // body 1
1589 // if (some_condition) {
1590 // body3: // new_true_region
1591 // // body3
1592 // } else {
1593 // goto body4;
1594 // }
1595 // } else {
1596 // // body 2
1597 // if (some_condition) {
1598 // goto body3;
1599 // } else {
1600 // body4: // new_false_region
1601 // // body4;
1602 // }
1603 // }
1604 //
1605
1606 // clone pinned nodes thru the resulting regions
1607 push_pinned_nodes_thru_region(dom_if, new_true_region);
1608 push_pinned_nodes_thru_region(dom_if, new_false_region);
1609
1610 // Optimize out the cloned ifs. Because pinned nodes were cloned, this also allows a CastPP that would be dependent
1611 // 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
1612 // unrelated control dependency.
1613 for (uint i = 1; i < new_false_region->req(); i++) {
1614 if (is_dominator(dom_proj_true, new_false_region->in(i))) {
1615 dominated_by(dom_proj_true->as_IfProj(), new_false_region->in(i)->in(0)->as_If());
1616 } else {
1617 assert(is_dominator(dom_proj_false, new_false_region->in(i)), "bad if");
1618 dominated_by(dom_proj_false->as_IfProj(), new_false_region->in(i)->in(0)->as_If());
1619 }
1620 }
1621 return true;
1622 }
1623 return false;
1624 }
1625
1626 void PhaseIdealLoop::push_pinned_nodes_thru_region(IfNode* dom_if, Node* region) {
1627 for (DUIterator i = region->outs(); region->has_out(i); i++) {
1628 Node* u = region->out(i);
1629 if (!has_ctrl(u) || u->is_Phi() || !u->depends_only_on_test() || !_igvn.no_dependent_zero_check(u)) {
1630 continue;
1631 }
1632 assert(u->in(0) == region, "not a control dependent node?");
1633 uint j = 1;
1634 for (; j < u->req(); ++j) {
1635 Node* in = u->in(j);
1636 if (!is_dominator(ctrl_or_self(in), dom_if)) {
1637 break;
1638 }
1639 }
1640 if (j == u->req()) {
1641 Node *phi = PhiNode::make_blank(region, u);
1642 for (uint k = 1; k < region->req(); ++k) {
1643 Node* clone = u->clone();
1644 clone->set_req(0, region->in(k));
1645 register_new_node(clone, region->in(k));
1646 phi->init_req(k, clone);
1647 }
1648 register_new_node(phi, region);
1649 _igvn.replace_node(u, phi);
1650 --i;
1651 }
1652 }
1653 }
1654
1655 bool PhaseIdealLoop::safe_for_if_replacement(const Node* dom) const {
1656 if (!dom->is_CountedLoopEnd()) {
1657 return true;
1658 }
1659 CountedLoopEndNode* le = dom->as_CountedLoopEnd();
1660 CountedLoopNode* cl = le->loopnode();
1661 if (cl == nullptr) {
1662 return true;
1663 }
1664 if (!cl->is_main_loop()) {
1665 return true;
1666 }
1667 if (cl->is_canonical_loop_entry() == nullptr) {
1668 return true;
1669 }
1670 // Further unrolling is possible so loop exit condition might change
1671 return false;
1672 }
1673
1674 // See if a shared loop-varying computation has no loop-varying uses.
1675 // Happens if something is only used for JVM state in uncommon trap exits,
1676 // like various versions of induction variable+offset. Clone the
1677 // computation per usage to allow it to sink out of the loop.
1678 void PhaseIdealLoop::try_sink_out_of_loop(Node* n) {
1679 if (has_ctrl(n) &&
1680 !n->is_Phi() &&
1681 !n->is_Bool() &&
1682 !n->is_Proj() &&
1683 !n->is_MergeMem() &&
1684 !n->is_CMove() &&
1685 !n->is_OpaqueNotNull() &&
1686 !n->is_OpaqueInitializedAssertionPredicate() &&
1687 !n->is_OpaqueTemplateAssertionPredicate() &&
1688 !n->is_Type()) {
1689 Node *n_ctrl = get_ctrl(n);
1690 IdealLoopTree *n_loop = get_loop(n_ctrl);
1691
1692 if (n->in(0) != nullptr) {
1693 IdealLoopTree* loop_ctrl = get_loop(n->in(0));
1694 if (n_loop != loop_ctrl && n_loop->is_member(loop_ctrl)) {
1695 // n has a control input inside a loop but get_ctrl() is member of an outer loop. This could happen, for example,
1696 // for Div nodes inside a loop (control input inside loop) without a use except for an UCT (outside the loop).
1697 // Rewire control of n to right outside of the loop, regardless if its input(s) are later sunk or not.
1698 Node* maybe_pinned_n = n;
1699 Node* outside_ctrl = place_outside_loop(n_ctrl, loop_ctrl);
1700 if (n->depends_only_on_test()) {
1701 Node* pinned_clone = n->pin_array_access_node();
1702 if (pinned_clone != nullptr) {
1703 // Pin array access nodes: if this is an array load, it's going to be dependent on a condition that's not a
1704 // range check for that access. If that condition is replaced by an identical dominating one, then an
1705 // unpinned load would risk floating above its range check.
1706 register_new_node(pinned_clone, n_ctrl);
1707 maybe_pinned_n = pinned_clone;
1708 _igvn.replace_node(n, pinned_clone);
1709 }
1710 }
1711 _igvn.replace_input_of(maybe_pinned_n, 0, outside_ctrl);
1712 }
1713 }
1714 if (n_loop != _ltree_root && n->outcnt() > 1) {
1715 // Compute early control: needed for anti-dependence analysis. It's also possible that as a result of
1716 // previous transformations in this loop opts round, the node can be hoisted now: early control will tell us.
1717 Node* early_ctrl = compute_early_ctrl(n, n_ctrl);
1718 if (n_loop->is_member(get_loop(early_ctrl)) && // check that this one can't be hoisted now
1719 ctrl_of_all_uses_out_of_loop(n, early_ctrl, n_loop)) { // All uses in outer loops!
1720 if (n->is_Store() || n->is_LoadStore()) {
1721 assert(false, "no node with a side effect");
1722 C->record_failure("no node with a side effect");
1723 return;
1724 }
1725 Node* outer_loop_clone = nullptr;
1726 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin;) {
1727 Node* u = n->last_out(j); // Clone private computation per use
1728 _igvn.rehash_node_delayed(u);
1729 Node* x = nullptr;
1730 if (n->depends_only_on_test()) {
1731 // Pin array access nodes: if this is an array load, it's going to be dependent on a condition that's not a
1732 // range check for that access. If that condition is replaced by an identical dominating one, then an
1733 // unpinned load would risk floating above its range check.
1734 x = n->pin_array_access_node();
1735 }
1736 if (x == nullptr) {
1737 x = n->clone();
1738 }
1739 Node* x_ctrl = nullptr;
1740 if (u->is_Phi()) {
1741 // Replace all uses of normal nodes. Replace Phi uses
1742 // individually, so the separate Nodes can sink down
1743 // different paths.
1744 uint k = 1;
1745 while (u->in(k) != n) k++;
1746 u->set_req(k, x);
1747 // x goes next to Phi input path
1748 x_ctrl = u->in(0)->in(k);
1749 // Find control for 'x' next to use but not inside inner loops.
1750 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1751 --j;
1752 } else { // Normal use
1753 if (has_ctrl(u)) {
1754 x_ctrl = get_ctrl(u);
1755 } else {
1756 x_ctrl = u->in(0);
1757 }
1758 // Find control for 'x' next to use but not inside inner loops.
1759 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1760 // Replace all uses
1761 if (u->is_ConstraintCast() && _igvn.type(n)->higher_equal(u->bottom_type()) && u->in(0) == x_ctrl) {
1762 // If we're sinking a chain of data nodes, we might have inserted a cast to pin the use which is not necessary
1763 // anymore now that we're going to pin n as well
1764 _igvn.replace_node(u, x);
1765 --j;
1766 } else {
1767 int nb = u->replace_edge(n, x, &_igvn);
1768 j -= nb;
1769 }
1770 }
1771
1772 if (n->is_Load()) {
1773 // For loads, add a control edge to a CFG node outside of the loop
1774 // to force them to not combine and return back inside the loop
1775 // during GVN optimization (4641526).
1776 assert(x_ctrl == get_late_ctrl_with_anti_dep(x->as_Load(), early_ctrl, x_ctrl), "anti-dependences were already checked");
1777
1778 IdealLoopTree* x_loop = get_loop(x_ctrl);
1779 Node* x_head = x_loop->_head;
1780 if (x_head->is_Loop() && x_head->is_OuterStripMinedLoop()) {
1781 // Do not add duplicate LoadNodes to the outer strip mined loop
1782 if (outer_loop_clone != nullptr) {
1783 _igvn.replace_node(x, outer_loop_clone);
1784 continue;
1785 }
1786 outer_loop_clone = x;
1787 }
1788 x->set_req(0, x_ctrl);
1789 } else if (n->in(0) != nullptr){
1790 x->set_req(0, x_ctrl);
1791 }
1792 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1793 assert(!n_loop->is_member(get_loop(x_ctrl)), "should have moved out of loop");
1794 register_new_node(x, x_ctrl);
1795
1796 // Chain of AddP nodes: (AddP base (AddP base (AddP base )))
1797 // All AddP nodes must keep the same base after sinking so:
1798 // 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,
1799 // their bases remain the same.
1800 // (see 2- below)
1801 assert(!x->is_AddP() || !x->in(AddPNode::Address)->is_AddP() ||
1802 x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base) ||
1803 !x->in(AddPNode::Address)->in(AddPNode::Base)->eqv_uncast(x->in(AddPNode::Base)), "unexpected AddP shape");
1804 if (x->in(0) == nullptr && !x->is_DecodeNarrowPtr() &&
1805 !(x->is_AddP() && x->in(AddPNode::Address)->is_AddP() && x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base))) {
1806 assert(!x->is_Load(), "load should be pinned");
1807 // Use a cast node to pin clone out of loop
1808 Node* cast = nullptr;
1809 for (uint k = 0; k < x->req(); k++) {
1810 Node* in = x->in(k);
1811 if (in != nullptr && n_loop->is_member(get_loop(get_ctrl(in)))) {
1812 const Type* in_t = _igvn.type(in);
1813 cast = ConstraintCastNode::make_cast_for_type(x_ctrl, in, in_t,
1814 ConstraintCastNode::UnconditionalDependency, nullptr);
1815 }
1816 if (cast != nullptr) {
1817 Node* prev = _igvn.hash_find_insert(cast);
1818 if (prev != nullptr && get_ctrl(prev) == x_ctrl) {
1819 cast->destruct(&_igvn);
1820 cast = prev;
1821 } else {
1822 register_new_node(cast, x_ctrl);
1823 }
1824 x->replace_edge(in, cast);
1825 // Chain of AddP nodes:
1826 // 2- A CastPP of the base is only added now that all AddP nodes are sunk
1827 if (x->is_AddP() && k == AddPNode::Base) {
1828 update_addp_chain_base(x, n->in(AddPNode::Base), cast);
1829 }
1830 break;
1831 }
1832 }
1833 assert(cast != nullptr, "must have added a cast to pin the node");
1834 }
1835 }
1836 _igvn.remove_dead_node(n);
1837 }
1838 _dom_lca_tags_round = 0;
1839 }
1840 }
1841 }
1842
1843 void PhaseIdealLoop::update_addp_chain_base(Node* x, Node* old_base, Node* new_base) {
1844 ResourceMark rm;
1845 Node_List wq;
1846 wq.push(x);
1847 while (wq.size() != 0) {
1848 Node* n = wq.pop();
1849 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1850 Node* u = n->fast_out(i);
1851 if (u->is_AddP() && u->in(AddPNode::Base) == old_base) {
1852 _igvn.replace_input_of(u, AddPNode::Base, new_base);
1853 wq.push(u);
1854 }
1855 }
1856 }
1857 }
1858
1859 // Compute the early control of a node by following its inputs until we reach
1860 // nodes that are pinned. Then compute the LCA of the control of all pinned nodes.
1861 Node* PhaseIdealLoop::compute_early_ctrl(Node* n, Node* n_ctrl) {
1862 Node* early_ctrl = nullptr;
1863 ResourceMark rm;
1864 Unique_Node_List wq;
1865 wq.push(n);
1866 for (uint i = 0; i < wq.size(); i++) {
1867 Node* m = wq.at(i);
1868 Node* c = nullptr;
1869 if (m->is_CFG()) {
1870 c = m;
1871 } else if (m->pinned()) {
1872 c = m->in(0);
1873 } else {
1874 for (uint j = 0; j < m->req(); j++) {
1875 Node* in = m->in(j);
1876 if (in != nullptr) {
1877 wq.push(in);
1878 }
1879 }
1880 }
1881 if (c != nullptr) {
1882 assert(is_dominator(c, n_ctrl), "control input must dominate current control");
1883 if (early_ctrl == nullptr || is_dominator(early_ctrl, c)) {
1884 early_ctrl = c;
1885 }
1886 }
1887 }
1888 assert(is_dominator(early_ctrl, n_ctrl), "early control must dominate current control");
1889 return early_ctrl;
1890 }
1891
1892 bool PhaseIdealLoop::ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop) {
1893 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1894 Node* u = n->fast_out(i);
1895 if (u->is_Opaque1()) {
1896 return false; // Found loop limit, bugfix for 4677003
1897 }
1898 // We can't reuse tags in PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal() so make sure calls to
1899 // get_late_ctrl_with_anti_dep() use their own tag
1900 _dom_lca_tags_round++;
1901 assert(_dom_lca_tags_round != 0, "shouldn't wrap around");
1902
1903 if (u->is_Phi()) {
1904 for (uint j = 1; j < u->req(); ++j) {
1905 if (u->in(j) == n && !ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, u->in(0)->in(j))) {
1906 return false;
1907 }
1908 }
1909 } else {
1910 Node* ctrl = has_ctrl(u) ? get_ctrl(u) : u->in(0);
1911 if (!ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, ctrl)) {
1912 return false;
1913 }
1914 }
1915 }
1916 return true;
1917 }
1918
1919 bool PhaseIdealLoop::ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl) {
1920 if (n->is_Load()) {
1921 ctrl = get_late_ctrl_with_anti_dep(n->as_Load(), n_ctrl, ctrl);
1922 }
1923 IdealLoopTree *u_loop = get_loop(ctrl);
1924 if (u_loop == n_loop) {
1925 return false; // Found loop-varying use
1926 }
1927 if (n_loop->is_member(u_loop)) {
1928 return false; // Found use in inner loop
1929 }
1930 // 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
1931 // to a check that's eliminated by range check elimination, it becomes input to an expression that feeds into the exit
1932 // test of the pre loop above the point in the graph where it's pinned.
1933 if (n_loop->_head->is_CountedLoop() && n_loop->_head->as_CountedLoop()->is_pre_loop()) {
1934 CountedLoopNode* pre_loop = n_loop->_head->as_CountedLoop();
1935 if (is_dominator(pre_loop->loopexit(), ctrl)) {
1936 return false;
1937 }
1938 }
1939 return true;
1940 }
1941
1942 //------------------------------split_if_with_blocks---------------------------
1943 // Check for aggressive application of 'split-if' optimization,
1944 // using basic block level info.
1945 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) {
1946 Node* root = C->root();
1947 visited.set(root->_idx); // first, mark root as visited
1948 // Do pre-visit work for root
1949 Node* n = split_if_with_blocks_pre(root);
1950 uint cnt = n->outcnt();
1951 uint i = 0;
1952
1953 while (true) {
1954 // Visit all children
1955 if (i < cnt) {
1956 Node* use = n->raw_out(i);
1957 ++i;
1958 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1959 // Now do pre-visit work for this use
1960 use = split_if_with_blocks_pre(use);
1961 nstack.push(n, i); // Save parent and next use's index.
1962 n = use; // Process all children of current use.
1963 cnt = use->outcnt();
1964 i = 0;
1965 }
1966 }
1967 else {
1968 // All of n's children have been processed, complete post-processing.
1969 if (cnt != 0 && !n->is_Con()) {
1970 assert(has_node(n), "no dead nodes");
1971 split_if_with_blocks_post(n);
1972 if (C->failing()) {
1973 return;
1974 }
1975 }
1976 if (must_throttle_split_if()) {
1977 nstack.clear();
1978 }
1979 if (nstack.is_empty()) {
1980 // Finished all nodes on stack.
1981 break;
1982 }
1983 // Get saved parent node and next use's index. Visit the rest of uses.
1984 n = nstack.node();
1985 cnt = n->outcnt();
1986 i = nstack.index();
1987 nstack.pop();
1988 }
1989 }
1990 }
1991
1992
1993 //=============================================================================
1994 //
1995 // C L O N E A L O O P B O D Y
1996 //
1997
1998 //------------------------------clone_iff--------------------------------------
1999 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2000 // "Nearly" because all Nodes have been cloned from the original in the loop,
2001 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2002 // through the Phi recursively, and return a Bool.
2003 Node* PhaseIdealLoop::clone_iff(PhiNode* phi) {
2004
2005 // Convert this Phi into a Phi merging Bools
2006 uint i;
2007 for (i = 1; i < phi->req(); i++) {
2008 Node* b = phi->in(i);
2009 if (b->is_Phi()) {
2010 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi()));
2011 } else {
2012 assert(b->is_Bool() || b->is_OpaqueNotNull() || b->is_OpaqueInitializedAssertionPredicate(),
2013 "bool, non-null check with OpaqueNotNull or Initialized Assertion Predicate with its Opaque node");
2014 }
2015 }
2016 Node* n = phi->in(1);
2017 Node* sample_opaque = nullptr;
2018 Node *sample_bool = nullptr;
2019 if (n->is_OpaqueNotNull() || n->is_OpaqueInitializedAssertionPredicate()) {
2020 sample_opaque = n;
2021 sample_bool = n->in(1);
2022 assert(sample_bool->is_Bool(), "wrong type");
2023 } else {
2024 sample_bool = n;
2025 }
2026 Node *sample_cmp = sample_bool->in(1);
2027
2028 // Make Phis to merge the Cmp's inputs.
2029 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
2030 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
2031 for (i = 1; i < phi->req(); i++) {
2032 Node *n1 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
2033 Node *n2 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
2034 phi1->set_req(i, n1);
2035 phi2->set_req(i, n2);
2036 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2037 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2038 }
2039 // See if these Phis have been made before.
2040 // Register with optimizer
2041 Node *hit1 = _igvn.hash_find_insert(phi1);
2042 if (hit1) { // Hit, toss just made Phi
2043 _igvn.remove_dead_node(phi1); // Remove new phi
2044 assert(hit1->is_Phi(), "" );
2045 phi1 = (PhiNode*)hit1; // Use existing phi
2046 } else { // Miss
2047 _igvn.register_new_node_with_optimizer(phi1);
2048 }
2049 Node *hit2 = _igvn.hash_find_insert(phi2);
2050 if (hit2) { // Hit, toss just made Phi
2051 _igvn.remove_dead_node(phi2); // Remove new phi
2052 assert(hit2->is_Phi(), "" );
2053 phi2 = (PhiNode*)hit2; // Use existing phi
2054 } else { // Miss
2055 _igvn.register_new_node_with_optimizer(phi2);
2056 }
2057 // Register Phis with loop/block info
2058 set_ctrl(phi1, phi->in(0));
2059 set_ctrl(phi2, phi->in(0));
2060 // Make a new Cmp
2061 Node *cmp = sample_cmp->clone();
2062 cmp->set_req(1, phi1);
2063 cmp->set_req(2, phi2);
2064 _igvn.register_new_node_with_optimizer(cmp);
2065 set_ctrl(cmp, phi->in(0));
2066
2067 // Make a new Bool
2068 Node *b = sample_bool->clone();
2069 b->set_req(1,cmp);
2070 _igvn.register_new_node_with_optimizer(b);
2071 set_ctrl(b, phi->in(0));
2072
2073 if (sample_opaque != nullptr) {
2074 Node* opaque = sample_opaque->clone();
2075 opaque->set_req(1, b);
2076 _igvn.register_new_node_with_optimizer(opaque);
2077 set_ctrl(opaque, phi->in(0));
2078 return opaque;
2079 }
2080
2081 assert(b->is_Bool(), "");
2082 return b;
2083 }
2084
2085 //------------------------------clone_bool-------------------------------------
2086 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2087 // "Nearly" because all Nodes have been cloned from the original in the loop,
2088 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2089 // through the Phi recursively, and return a Bool.
2090 CmpNode*PhaseIdealLoop::clone_bool(PhiNode* phi) {
2091 uint i;
2092 // Convert this Phi into a Phi merging Bools
2093 for( i = 1; i < phi->req(); i++ ) {
2094 Node *b = phi->in(i);
2095 if( b->is_Phi() ) {
2096 _igvn.replace_input_of(phi, i, clone_bool(b->as_Phi()));
2097 } else {
2098 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
2099 }
2100 }
2101
2102 Node *sample_cmp = phi->in(1);
2103
2104 // Make Phis to merge the Cmp's inputs.
2105 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
2106 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
2107 for( uint j = 1; j < phi->req(); j++ ) {
2108 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
2109 Node *n1, *n2;
2110 if( cmp_top->is_Cmp() ) {
2111 n1 = cmp_top->in(1);
2112 n2 = cmp_top->in(2);
2113 } else {
2114 n1 = n2 = cmp_top;
2115 }
2116 phi1->set_req( j, n1 );
2117 phi2->set_req( j, n2 );
2118 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2119 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2120 }
2121
2122 // See if these Phis have been made before.
2123 // Register with optimizer
2124 Node *hit1 = _igvn.hash_find_insert(phi1);
2125 if( hit1 ) { // Hit, toss just made Phi
2126 _igvn.remove_dead_node(phi1); // Remove new phi
2127 assert( hit1->is_Phi(), "" );
2128 phi1 = (PhiNode*)hit1; // Use existing phi
2129 } else { // Miss
2130 _igvn.register_new_node_with_optimizer(phi1);
2131 }
2132 Node *hit2 = _igvn.hash_find_insert(phi2);
2133 if( hit2 ) { // Hit, toss just made Phi
2134 _igvn.remove_dead_node(phi2); // Remove new phi
2135 assert( hit2->is_Phi(), "" );
2136 phi2 = (PhiNode*)hit2; // Use existing phi
2137 } else { // Miss
2138 _igvn.register_new_node_with_optimizer(phi2);
2139 }
2140 // Register Phis with loop/block info
2141 set_ctrl(phi1, phi->in(0));
2142 set_ctrl(phi2, phi->in(0));
2143 // Make a new Cmp
2144 Node *cmp = sample_cmp->clone();
2145 cmp->set_req( 1, phi1 );
2146 cmp->set_req( 2, phi2 );
2147 _igvn.register_new_node_with_optimizer(cmp);
2148 set_ctrl(cmp, phi->in(0));
2149
2150 assert( cmp->is_Cmp(), "" );
2151 return (CmpNode*)cmp;
2152 }
2153
2154 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
2155 IdealLoopTree* loop, IdealLoopTree* outer_loop,
2156 Node_List*& split_if_set, Node_List*& split_bool_set,
2157 Node_List*& split_cex_set, Node_List& worklist,
2158 uint new_counter, CloneLoopMode mode) {
2159 Node* nnn = old_new[old->_idx];
2160 // Copy uses to a worklist, so I can munge the def-use info
2161 // with impunity.
2162 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2163 worklist.push(old->fast_out(j));
2164
2165 while( worklist.size() ) {
2166 Node *use = worklist.pop();
2167 if (!has_node(use)) continue; // Ignore dead nodes
2168 if (use->in(0) == C->top()) continue;
2169 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2170 // Check for data-use outside of loop - at least one of OLD or USE
2171 // must not be a CFG node.
2172 #ifdef ASSERT
2173 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == nullptr) {
2174 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
2175 assert(mode != IgnoreStripMined, "incorrect cloning mode");
2176 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node");
2177 }
2178 #endif
2179 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
2180
2181 // If the Data use is an IF, that means we have an IF outside the
2182 // loop that is switching on a condition that is set inside the
2183 // loop. Happens if people set a loop-exit flag; then test the flag
2184 // in the loop to break the loop, then test is again outside the
2185 // loop to determine which way the loop exited.
2186 //
2187 // For several uses we need to make sure that there is no phi between,
2188 // the use and the Bool/Cmp. We therefore clone the Bool/Cmp down here
2189 // to avoid such a phi in between.
2190 // For example, it is unexpected that there is a Phi between an
2191 // AllocateArray node and its ValidLengthTest input that could cause
2192 // split if to break.
2193 assert(!use->is_OpaqueTemplateAssertionPredicate(),
2194 "should not clone a Template Assertion Predicate which should be removed once it's useless");
2195 if (use->is_If() || use->is_CMove() || use->is_OpaqueNotNull() || use->is_OpaqueInitializedAssertionPredicate() ||
2196 (use->Opcode() == Op_AllocateArray && use->in(AllocateNode::ValidLengthTest) == old)) {
2197 // Since this code is highly unlikely, we lazily build the worklist
2198 // of such Nodes to go split.
2199 if (!split_if_set) {
2200 split_if_set = new Node_List();
2201 }
2202 split_if_set->push(use);
2203 }
2204 if (use->is_Bool()) {
2205 if (!split_bool_set) {
2206 split_bool_set = new Node_List();
2207 }
2208 split_bool_set->push(use);
2209 }
2210 if (use->Opcode() == Op_CreateEx) {
2211 if (!split_cex_set) {
2212 split_cex_set = new Node_List();
2213 }
2214 split_cex_set->push(use);
2215 }
2216
2217
2218 // Get "block" use is in
2219 uint idx = 0;
2220 while( use->in(idx) != old ) idx++;
2221 Node *prev = use->is_CFG() ? use : get_ctrl(use);
2222 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
2223 Node* cfg = (prev->_idx >= new_counter && prev->is_Region())
2224 ? prev->in(2)
2225 : idom(prev);
2226 if( use->is_Phi() ) // Phi use is in prior block
2227 cfg = prev->in(idx); // NOT in block of Phi itself
2228 if (cfg->is_top()) { // Use is dead?
2229 _igvn.replace_input_of(use, idx, C->top());
2230 continue;
2231 }
2232
2233 // If use is referenced through control edge... (idx == 0)
2234 if (mode == IgnoreStripMined && idx == 0) {
2235 LoopNode *head = loop->_head->as_Loop();
2236 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
2237 // That node is outside the inner loop, leave it outside the
2238 // outer loop as well to not confuse verification code.
2239 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
2240 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
2241 continue;
2242 }
2243 }
2244
2245 while(!outer_loop->is_member(get_loop(cfg))) {
2246 prev = cfg;
2247 cfg = (cfg->_idx >= new_counter && cfg->is_Region()) ? cfg->in(2) : idom(cfg);
2248 }
2249 // If the use occurs after merging several exits from the loop, then
2250 // old value must have dominated all those exits. Since the same old
2251 // value was used on all those exits we did not need a Phi at this
2252 // merge point. NOW we do need a Phi here. Each loop exit value
2253 // is now merged with the peeled body exit; each exit gets its own
2254 // private Phi and those Phis need to be merged here.
2255 Node *phi;
2256 if( prev->is_Region() ) {
2257 if( idx == 0 ) { // Updating control edge?
2258 phi = prev; // Just use existing control
2259 } else { // Else need a new Phi
2260 phi = PhiNode::make( prev, old );
2261 // Now recursively fix up the new uses of old!
2262 for( uint i = 1; i < prev->req(); i++ ) {
2263 worklist.push(phi); // Onto worklist once for each 'old' input
2264 }
2265 }
2266 } else {
2267 // Get new RegionNode merging old and new loop exits
2268 prev = old_new[prev->_idx];
2269 assert( prev, "just made this in step 7" );
2270 if( idx == 0) { // Updating control edge?
2271 phi = prev; // Just use existing control
2272 } else { // Else need a new Phi
2273 // Make a new Phi merging data values properly
2274 phi = PhiNode::make( prev, old );
2275 phi->set_req( 1, nnn );
2276 }
2277 }
2278 // If inserting a new Phi, check for prior hits
2279 if( idx != 0 ) {
2280 Node *hit = _igvn.hash_find_insert(phi);
2281 if( hit == nullptr ) {
2282 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2283 } else { // or
2284 // Remove the new phi from the graph and use the hit
2285 _igvn.remove_dead_node(phi);
2286 phi = hit; // Use existing phi
2287 }
2288 set_ctrl(phi, prev);
2289 }
2290 // Make 'use' use the Phi instead of the old loop body exit value
2291 assert(use->in(idx) == old, "old is still input of use");
2292 // We notify all uses of old, including use, and the indirect uses,
2293 // that may now be optimized because we have replaced old with phi.
2294 _igvn.add_users_to_worklist(old);
2295 if (idx == 0 &&
2296 use->depends_only_on_test()) {
2297 Node* pinned_clone = use->pin_array_access_node();
2298 if (pinned_clone != nullptr) {
2299 // Pin array access nodes: control is updated here to a region. If, after some transformations, only one path
2300 // into the region is left, an array load could become dependent on a condition that's not a range check for
2301 // that access. If that condition is replaced by an identical dominating one, then an unpinned load would risk
2302 // floating above its range check.
2303 pinned_clone->set_req(0, phi);
2304 register_new_node_with_ctrl_of(pinned_clone, use);
2305 _igvn.replace_node(use, pinned_clone);
2306 continue;
2307 }
2308 }
2309 _igvn.replace_input_of(use, idx, phi);
2310 if( use->_idx >= new_counter ) { // If updating new phis
2311 // Not needed for correctness, but prevents a weak assert
2312 // in AddPNode from tripping (when we end up with different
2313 // base & derived Phis that will become the same after
2314 // IGVN does CSE).
2315 Node *hit = _igvn.hash_find_insert(use);
2316 if( hit ) // Go ahead and re-hash for hits.
2317 _igvn.replace_node( use, hit );
2318 }
2319 }
2320 }
2321 }
2322
2323 static void collect_nodes_in_outer_loop_not_reachable_from_sfpt(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop,
2324 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase,
2325 bool check_old_new) {
2326 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2327 Node* u = n->fast_out(j);
2328 assert(check_old_new || old_new[u->_idx] == nullptr, "shouldn't have been cloned");
2329 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == nullptr)) {
2330 Node* c = phase->get_ctrl(u);
2331 IdealLoopTree* u_loop = phase->get_loop(c);
2332 assert(!loop->is_member(u_loop) || !loop->_body.contains(u), "can be in outer loop or out of both loops only");
2333 if (!loop->is_member(u_loop)) {
2334 if (outer_loop->is_member(u_loop)) {
2335 wq.push(u);
2336 } else {
2337 // nodes pinned with control in the outer loop but not referenced from the safepoint must be moved out of
2338 // the outer loop too
2339 Node* u_c = u->in(0);
2340 if (u_c != nullptr) {
2341 IdealLoopTree* u_c_loop = phase->get_loop(u_c);
2342 if (outer_loop->is_member(u_c_loop) && !loop->is_member(u_c_loop)) {
2343 wq.push(u);
2344 }
2345 }
2346 }
2347 }
2348 }
2349 }
2350 }
2351
2352 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2353 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2354 Node_List& extra_data_nodes) {
2355 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2356 CountedLoopNode* cl = head->as_CountedLoop();
2357 Node* l = cl->outer_loop();
2358 Node* tail = cl->outer_loop_tail();
2359 IfNode* le = cl->outer_loop_end();
2360 Node* sfpt = cl->outer_safepoint();
2361 CountedLoopEndNode* cle = cl->loopexit();
2362 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2363 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2364 Node* cle_out = cle->proj_out(false);
2365
2366 Node* new_sfpt = nullptr;
2367 Node* new_cle_out = cle_out->clone();
2368 old_new.map(cle_out->_idx, new_cle_out);
2369 if (mode == CloneIncludesStripMined) {
2370 // clone outer loop body
2371 Node* new_l = l->clone();
2372 Node* new_tail = tail->clone();
2373 IfNode* new_le = le->clone()->as_If();
2374 new_sfpt = sfpt->clone();
2375
2376 set_loop(new_l, outer_loop->_parent);
2377 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2378 set_loop(new_cle_out, outer_loop->_parent);
2379 set_idom(new_cle_out, new_cle, dd);
2380 set_loop(new_sfpt, outer_loop->_parent);
2381 set_idom(new_sfpt, new_cle_out, dd);
2382 set_loop(new_le, outer_loop->_parent);
2383 set_idom(new_le, new_sfpt, dd);
2384 set_loop(new_tail, outer_loop->_parent);
2385 set_idom(new_tail, new_le, dd);
2386 set_idom(new_cl, new_l, dd);
2387
2388 old_new.map(l->_idx, new_l);
2389 old_new.map(tail->_idx, new_tail);
2390 old_new.map(le->_idx, new_le);
2391 old_new.map(sfpt->_idx, new_sfpt);
2392
2393 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2394 new_l->set_req(0, new_l);
2395 new_tail->set_req(0, new_le);
2396 new_le->set_req(0, new_sfpt);
2397 new_sfpt->set_req(0, new_cle_out);
2398 new_cle_out->set_req(0, new_cle);
2399 new_cl->set_req(LoopNode::EntryControl, new_l);
2400
2401 _igvn.register_new_node_with_optimizer(new_l);
2402 _igvn.register_new_node_with_optimizer(new_tail);
2403 _igvn.register_new_node_with_optimizer(new_le);
2404 } else {
2405 Node *newhead = old_new[loop->_head->_idx];
2406 newhead->as_Loop()->clear_strip_mined();
2407 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2408 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2409 }
2410 // Look at data node that were assigned a control in the outer
2411 // loop: they are kept in the outer loop by the safepoint so start
2412 // from the safepoint node's inputs.
2413 IdealLoopTree* outer_loop = get_loop(l);
2414 Node_Stack stack(2);
2415 stack.push(sfpt, 1);
2416 uint new_counter = C->unique();
2417 while (stack.size() > 0) {
2418 Node* n = stack.node();
2419 uint i = stack.index();
2420 while (i < n->req() &&
2421 (n->in(i) == nullptr ||
2422 !has_ctrl(n->in(i)) ||
2423 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2424 (old_new[n->in(i)->_idx] != nullptr && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2425 i++;
2426 }
2427 if (i < n->req()) {
2428 stack.set_index(i+1);
2429 stack.push(n->in(i), 0);
2430 } else {
2431 assert(old_new[n->_idx] == nullptr || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2432 Node* m = n == sfpt ? new_sfpt : n->clone();
2433 if (m != nullptr) {
2434 for (uint i = 0; i < n->req(); i++) {
2435 if (m->in(i) != nullptr && old_new[m->in(i)->_idx] != nullptr) {
2436 m->set_req(i, old_new[m->in(i)->_idx]);
2437 }
2438 }
2439 } else {
2440 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2441 }
2442 if (n != sfpt) {
2443 extra_data_nodes.push(n);
2444 _igvn.register_new_node_with_optimizer(m);
2445 assert(get_ctrl(n) == cle_out, "what other control?");
2446 set_ctrl(m, new_cle_out);
2447 old_new.map(n->_idx, m);
2448 }
2449 stack.pop();
2450 }
2451 }
2452 if (mode == CloneIncludesStripMined) {
2453 _igvn.register_new_node_with_optimizer(new_sfpt);
2454 _igvn.register_new_node_with_optimizer(new_cle_out);
2455 }
2456 // Some other transformation may have pessimistically assigned some
2457 // data nodes to the outer loop. Set their control so they are out
2458 // of the outer loop.
2459 ResourceMark rm;
2460 Unique_Node_List wq;
2461 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2462 Node* old = extra_data_nodes.at(i);
2463 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2464 }
2465
2466 for (uint i = 0; i < loop->_body.size(); i++) {
2467 Node* old = loop->_body.at(i);
2468 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2469 }
2470
2471 Node* inner_out = sfpt->in(0);
2472 if (inner_out->outcnt() > 1) {
2473 collect_nodes_in_outer_loop_not_reachable_from_sfpt(inner_out, loop, outer_loop, old_new, wq, this, true);
2474 }
2475
2476 Node* new_ctrl = cl->outer_loop_exit();
2477 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest");
2478 for (uint i = 0; i < wq.size(); i++) {
2479 Node* n = wq.at(i);
2480 set_ctrl(n, new_ctrl);
2481 if (n->in(0) != nullptr) {
2482 _igvn.replace_input_of(n, 0, new_ctrl);
2483 }
2484 collect_nodes_in_outer_loop_not_reachable_from_sfpt(n, loop, outer_loop, old_new, wq, this, false);
2485 }
2486 } else {
2487 Node *newhead = old_new[loop->_head->_idx];
2488 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2489 }
2490 }
2491
2492 //------------------------------clone_loop-------------------------------------
2493 //
2494 // C L O N E A L O O P B O D Y
2495 //
2496 // This is the basic building block of the loop optimizations. It clones an
2497 // entire loop body. It makes an old_new loop body mapping; with this mapping
2498 // you can find the new-loop equivalent to an old-loop node. All new-loop
2499 // nodes are exactly equal to their old-loop counterparts, all edges are the
2500 // same. All exits from the old-loop now have a RegionNode that merges the
2501 // equivalent new-loop path. This is true even for the normal "loop-exit"
2502 // condition. All uses of loop-invariant old-loop values now come from (one
2503 // or more) Phis that merge their new-loop equivalents.
2504 //
2505 // This operation leaves the graph in an illegal state: there are two valid
2506 // control edges coming from the loop pre-header to both loop bodies. I'll
2507 // definitely have to hack the graph after running this transform.
2508 //
2509 // From this building block I will further edit edges to perform loop peeling
2510 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2511 //
2512 // Parameter side_by_size_idom:
2513 // When side_by_size_idom is null, the dominator tree is constructed for
2514 // the clone loop to dominate the original. Used in construction of
2515 // pre-main-post loop sequence.
2516 // When nonnull, the clone and original are side-by-side, both are
2517 // dominated by the side_by_side_idom node. Used in construction of
2518 // unswitched loops.
2519 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2520 CloneLoopMode mode, Node* side_by_side_idom) {
2521
2522 LoopNode* head = loop->_head->as_Loop();
2523 head->verify_strip_mined(1);
2524
2525 if (C->do_vector_loop() && PrintOpto) {
2526 const char* mname = C->method()->name()->as_quoted_ascii();
2527 if (mname != nullptr) {
2528 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2529 }
2530 }
2531
2532 CloneMap& cm = C->clone_map();
2533 if (C->do_vector_loop()) {
2534 cm.set_clone_idx(cm.max_gen()+1);
2535 #ifndef PRODUCT
2536 if (PrintOpto) {
2537 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2538 loop->dump_head();
2539 }
2540 #endif
2541 }
2542
2543 // Step 1: Clone the loop body. Make the old->new mapping.
2544 clone_loop_body(loop->_body, old_new, &cm);
2545
2546 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2547
2548 // Step 2: Fix the edges in the new body. If the old input is outside the
2549 // loop use it. If the old input is INside the loop, use the corresponding
2550 // new node instead.
2551 fix_body_edges(loop->_body, loop, old_new, dd, outer_loop->_parent, false);
2552
2553 Node_List extra_data_nodes; // data nodes in the outer strip mined loop
2554 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2555
2556 // Step 3: Now fix control uses. Loop varying control uses have already
2557 // been fixed up (as part of all input edges in Step 2). Loop invariant
2558 // control uses must be either an IfFalse or an IfTrue. Make a merge
2559 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2560 // refer to this.
2561 Node_List worklist;
2562 uint new_counter = C->unique();
2563 fix_ctrl_uses(loop->_body, loop, old_new, mode, side_by_side_idom, &cm, worklist);
2564
2565 // Step 4: If loop-invariant use is not control, it must be dominated by a
2566 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2567 // there if needed. Make a Phi there merging old and new used values.
2568 Node_List *split_if_set = nullptr;
2569 Node_List *split_bool_set = nullptr;
2570 Node_List *split_cex_set = nullptr;
2571 fix_data_uses(loop->_body, loop, mode, outer_loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
2572
2573 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2574 Node* old = extra_data_nodes.at(i);
2575 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2576 split_bool_set, split_cex_set, worklist, new_counter,
2577 mode);
2578 }
2579
2580 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2581 // the loop uses a condition set in the loop. The original IF probably
2582 // takes control from one or more OLD Regions (which in turn get from NEW
2583 // Regions). In any case, there will be a set of Phis for each merge point
2584 // from the IF up to where the original BOOL def exists the loop.
2585 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
2586
2587 }
2588
2589 void PhaseIdealLoop::finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set) {
2590 if (split_if_set) {
2591 while (split_if_set->size()) {
2592 Node *iff = split_if_set->pop();
2593 uint input = iff->Opcode() == Op_AllocateArray ? AllocateNode::ValidLengthTest : 1;
2594 if (iff->in(input)->is_Phi()) {
2595 Node *b = clone_iff(iff->in(input)->as_Phi());
2596 _igvn.replace_input_of(iff, input, b);
2597 }
2598 }
2599 }
2600 if (split_bool_set) {
2601 while (split_bool_set->size()) {
2602 Node *b = split_bool_set->pop();
2603 Node *phi = b->in(1);
2604 assert(phi->is_Phi(), "");
2605 CmpNode *cmp = clone_bool((PhiNode*) phi);
2606 _igvn.replace_input_of(b, 1, cmp);
2607 }
2608 }
2609 if (split_cex_set) {
2610 while (split_cex_set->size()) {
2611 Node *b = split_cex_set->pop();
2612 assert(b->in(0)->is_Region(), "");
2613 assert(b->in(1)->is_Phi(), "");
2614 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2615 split_up(b, b->in(0), nullptr);
2616 }
2617 }
2618 }
2619
2620 void PhaseIdealLoop::fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop,
2621 uint new_counter, Node_List &old_new, Node_List &worklist, Node_List*& split_if_set,
2622 Node_List*& split_bool_set, Node_List*& split_cex_set) {
2623 for(uint i = 0; i < body.size(); i++ ) {
2624 Node* old = body.at(i);
2625 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2626 split_bool_set, split_cex_set, worklist, new_counter,
2627 mode);
2628 }
2629 }
2630
2631 void PhaseIdealLoop::fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode,
2632 Node* side_by_side_idom, CloneMap* cm, Node_List &worklist) {
2633 LoopNode* head = loop->_head->as_Loop();
2634 for(uint i = 0; i < body.size(); i++ ) {
2635 Node* old = body.at(i);
2636 if( !old->is_CFG() ) continue;
2637
2638 // Copy uses to a worklist, so I can munge the def-use info
2639 // with impunity.
2640 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) {
2641 worklist.push(old->fast_out(j));
2642 }
2643
2644 while (worklist.size()) { // Visit all uses
2645 Node *use = worklist.pop();
2646 if (!has_node(use)) continue; // Ignore dead nodes
2647 IdealLoopTree *use_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use );
2648 if (!loop->is_member(use_loop) && use->is_CFG()) {
2649 // Both OLD and USE are CFG nodes here.
2650 assert(use->is_Proj(), "" );
2651 Node* nnn = old_new[old->_idx];
2652
2653 Node* newuse = nullptr;
2654 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2655 CountedLoopNode* cl = head->as_CountedLoop();
2656 CountedLoopEndNode* cle = cl->loopexit();
2657 Node* cle_out = cle->proj_out_or_null(false);
2658 if (use == cle_out) {
2659 IfNode* le = cl->outer_loop_end();
2660 use = le->proj_out(false);
2661 use_loop = get_loop(use);
2662 if (mode == CloneIncludesStripMined) {
2663 nnn = old_new[le->_idx];
2664 } else {
2665 newuse = old_new[cle_out->_idx];
2666 }
2667 }
2668 }
2669 if (newuse == nullptr) {
2670 newuse = use->clone();
2671 }
2672
2673 // Clone the loop exit control projection
2674 if (C->do_vector_loop() && cm != nullptr) {
2675 cm->verify_insert_and_clone(use, newuse, cm->clone_idx());
2676 }
2677 newuse->set_req(0,nnn);
2678 _igvn.register_new_node_with_optimizer(newuse);
2679 set_loop(newuse, use_loop);
2680 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2681
2682 // We need a Region to merge the exit from the peeled body and the
2683 // exit from the old loop body.
2684 RegionNode *r = new RegionNode(3);
2685 uint dd_r = MIN2(dom_depth(newuse), dom_depth(use));
2686 assert(dd_r >= dom_depth(dom_lca(newuse, use)), "" );
2687
2688 // The original user of 'use' uses 'r' instead.
2689 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2690 Node* useuse = use->last_out(l);
2691 _igvn.rehash_node_delayed(useuse);
2692 uint uses_found = 0;
2693 if (useuse->in(0) == use) {
2694 useuse->set_req(0, r);
2695 uses_found++;
2696 if (useuse->is_CFG()) {
2697 // This is not a dom_depth > dd_r because when new
2698 // control flow is constructed by a loop opt, a node and
2699 // its dominator can end up at the same dom_depth
2700 assert(dom_depth(useuse) >= dd_r, "");
2701 set_idom(useuse, r, dom_depth(useuse));
2702 }
2703 }
2704 for (uint k = 1; k < useuse->req(); k++) {
2705 if( useuse->in(k) == use ) {
2706 useuse->set_req(k, r);
2707 uses_found++;
2708 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2709 // This is not a dom_depth > dd_r because when new
2710 // control flow is constructed by a loop opt, a node
2711 // and its dominator can end up at the same dom_depth
2712 assert(dom_depth(useuse) >= dd_r , "");
2713 set_idom(useuse, r, dom_depth(useuse));
2714 }
2715 }
2716 }
2717 l -= uses_found; // we deleted 1 or more copies of this edge
2718 }
2719
2720 assert(use->is_Proj(), "loop exit should be projection");
2721 // lazy_replace() below moves all nodes that are:
2722 // - control dependent on the loop exit or
2723 // - have control set to the loop exit
2724 // below the post-loop merge point. lazy_replace() takes a dead control as first input. To make it
2725 // possible to use it, the loop exit projection is cloned and becomes the new exit projection. The initial one
2726 // becomes dead and is "replaced" by the region.
2727 Node* use_clone = use->clone();
2728 register_control(use_clone, use_loop, idom(use), dom_depth(use));
2729 // Now finish up 'r'
2730 r->set_req(1, newuse);
2731 r->set_req(2, use_clone);
2732 _igvn.register_new_node_with_optimizer(r);
2733 set_loop(r, use_loop);
2734 set_idom(r, (side_by_side_idom == nullptr) ? newuse->in(0) : side_by_side_idom, dd_r);
2735 lazy_replace(use, r);
2736 // Map the (cloned) old use to the new merge point
2737 old_new.map(use_clone->_idx, r);
2738 } // End of if a loop-exit test
2739 }
2740 }
2741 }
2742
2743 void PhaseIdealLoop::fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd,
2744 IdealLoopTree* parent, bool partial) {
2745 for(uint i = 0; i < body.size(); i++ ) {
2746 Node *old = body.at(i);
2747 Node *nnn = old_new[old->_idx];
2748 // Fix CFG/Loop controlling the new node
2749 if (has_ctrl(old)) {
2750 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2751 } else {
2752 set_loop(nnn, parent);
2753 if (old->outcnt() > 0) {
2754 Node* dom = idom(old);
2755 if (old_new[dom->_idx] != nullptr) {
2756 dom = old_new[dom->_idx];
2757 set_idom(nnn, dom, dd );
2758 }
2759 }
2760 }
2761 // Correct edges to the new node
2762 for (uint j = 0; j < nnn->req(); j++) {
2763 Node *n = nnn->in(j);
2764 if (n != nullptr) {
2765 IdealLoopTree *old_in_loop = get_loop(has_ctrl(n) ? get_ctrl(n) : n);
2766 if (loop->is_member(old_in_loop)) {
2767 if (old_new[n->_idx] != nullptr) {
2768 nnn->set_req(j, old_new[n->_idx]);
2769 } else {
2770 assert(!body.contains(n), "");
2771 assert(partial, "node not cloned");
2772 }
2773 }
2774 }
2775 }
2776 _igvn.hash_find_insert(nnn);
2777 }
2778 }
2779
2780 void PhaseIdealLoop::clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm) {
2781 for (uint i = 0; i < body.size(); i++) {
2782 Node* old = body.at(i);
2783 Node* nnn = old->clone();
2784 old_new.map(old->_idx, nnn);
2785 if (C->do_vector_loop() && cm != nullptr) {
2786 cm->verify_insert_and_clone(old, nnn, cm->clone_idx());
2787 }
2788 _igvn.register_new_node_with_optimizer(nnn);
2789 }
2790 }
2791
2792
2793 //---------------------- stride_of_possible_iv -------------------------------------
2794 // Looks for an iff/bool/comp with one operand of the compare
2795 // being a cycle involving an add and a phi,
2796 // with an optional truncation (left-shift followed by a right-shift)
2797 // of the add. Returns zero if not an iv.
2798 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2799 Node* trunc1 = nullptr;
2800 Node* trunc2 = nullptr;
2801 const TypeInteger* ttype = nullptr;
2802 if (!iff->is_If() || iff->in(1) == nullptr || !iff->in(1)->is_Bool()) {
2803 return 0;
2804 }
2805 BoolNode* bl = iff->in(1)->as_Bool();
2806 Node* cmp = bl->in(1);
2807 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2808 return 0;
2809 }
2810 // Must have an invariant operand
2811 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2812 return 0;
2813 }
2814 Node* add2 = nullptr;
2815 Node* cmp1 = cmp->in(1);
2816 if (cmp1->is_Phi()) {
2817 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2818 Node* phi = cmp1;
2819 for (uint i = 1; i < phi->req(); i++) {
2820 Node* in = phi->in(i);
2821 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2822 &trunc1, &trunc2, &ttype, T_INT);
2823 if (add && add->in(1) == phi) {
2824 add2 = add->in(2);
2825 break;
2826 }
2827 }
2828 } else {
2829 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2830 Node* addtrunc = cmp1;
2831 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2832 &trunc1, &trunc2, &ttype, T_INT);
2833 if (add && add->in(1)->is_Phi()) {
2834 Node* phi = add->in(1);
2835 for (uint i = 1; i < phi->req(); i++) {
2836 if (phi->in(i) == addtrunc) {
2837 add2 = add->in(2);
2838 break;
2839 }
2840 }
2841 }
2842 }
2843 if (add2 != nullptr) {
2844 const TypeInt* add2t = _igvn.type(add2)->is_int();
2845 if (add2t->is_con()) {
2846 return add2t->get_con();
2847 }
2848 }
2849 return 0;
2850 }
2851
2852
2853 //---------------------- stay_in_loop -------------------------------------
2854 // Return the (unique) control output node that's in the loop (if it exists.)
2855 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2856 Node* unique = nullptr;
2857 if (!n) return nullptr;
2858 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2859 Node* use = n->fast_out(i);
2860 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2861 if (unique != nullptr) {
2862 return nullptr;
2863 }
2864 unique = use;
2865 }
2866 }
2867 return unique;
2868 }
2869
2870 //------------------------------ register_node -------------------------------------
2871 // Utility to register node "n" with PhaseIdealLoop
2872 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree* loop, Node* pred, uint ddepth) {
2873 _igvn.register_new_node_with_optimizer(n);
2874 loop->_body.push(n);
2875 if (n->is_CFG()) {
2876 set_loop(n, loop);
2877 set_idom(n, pred, ddepth);
2878 } else {
2879 set_ctrl(n, pred);
2880 }
2881 }
2882
2883 //------------------------------ proj_clone -------------------------------------
2884 // Utility to create an if-projection
2885 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2886 ProjNode* c = p->clone()->as_Proj();
2887 c->set_req(0, iff);
2888 return c;
2889 }
2890
2891 //------------------------------ short_circuit_if -------------------------------------
2892 // Force the iff control output to be the live_proj
2893 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2894 guarantee(live_proj != nullptr, "null projection");
2895 int proj_con = live_proj->_con;
2896 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2897 Node* con = intcon(proj_con);
2898 if (iff) {
2899 iff->set_req(1, con);
2900 }
2901 return con;
2902 }
2903
2904 //------------------------------ insert_if_before_proj -------------------------------------
2905 // Insert a new if before an if projection (* - new node)
2906 //
2907 // before
2908 // if(test)
2909 // / \
2910 // v v
2911 // other-proj proj (arg)
2912 //
2913 // after
2914 // if(test)
2915 // / \
2916 // / v
2917 // | * proj-clone
2918 // v |
2919 // other-proj v
2920 // * new_if(relop(cmp[IU](left,right)))
2921 // / \
2922 // v v
2923 // * new-proj proj
2924 // (returned)
2925 //
2926 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2927 IfNode* iff = proj->in(0)->as_If();
2928 IdealLoopTree *loop = get_loop(proj);
2929 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2930 uint ddepth = dom_depth(proj);
2931
2932 _igvn.rehash_node_delayed(iff);
2933 _igvn.rehash_node_delayed(proj);
2934
2935 proj->set_req(0, nullptr); // temporary disconnect
2936 ProjNode* proj2 = proj_clone(proj, iff);
2937 register_node(proj2, loop, iff, ddepth);
2938
2939 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2940 register_node(cmp, loop, proj2, ddepth);
2941
2942 BoolNode* bol = new BoolNode(cmp, relop);
2943 register_node(bol, loop, proj2, ddepth);
2944
2945 int opcode = iff->Opcode();
2946 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2947 IfNode* new_if = IfNode::make_with_same_profile(iff, proj2, bol);
2948 register_node(new_if, loop, proj2, ddepth);
2949
2950 proj->set_req(0, new_if); // reattach
2951 set_idom(proj, new_if, ddepth);
2952
2953 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2954 guarantee(new_exit != nullptr, "null exit node");
2955 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2956
2957 return new_exit;
2958 }
2959
2960 //------------------------------ insert_region_before_proj -------------------------------------
2961 // Insert a region before an if projection (* - new node)
2962 //
2963 // before
2964 // if(test)
2965 // / |
2966 // v |
2967 // proj v
2968 // other-proj
2969 //
2970 // after
2971 // if(test)
2972 // / |
2973 // v |
2974 // * proj-clone v
2975 // | other-proj
2976 // v
2977 // * new-region
2978 // |
2979 // v
2980 // * dum_if
2981 // / \
2982 // v \
2983 // * dum-proj v
2984 // proj
2985 //
2986 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2987 IfNode* iff = proj->in(0)->as_If();
2988 IdealLoopTree *loop = get_loop(proj);
2989 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2990 uint ddepth = dom_depth(proj);
2991
2992 _igvn.rehash_node_delayed(iff);
2993 _igvn.rehash_node_delayed(proj);
2994
2995 proj->set_req(0, nullptr); // temporary disconnect
2996 ProjNode* proj2 = proj_clone(proj, iff);
2997 register_node(proj2, loop, iff, ddepth);
2998
2999 RegionNode* reg = new RegionNode(2);
3000 reg->set_req(1, proj2);
3001 register_node(reg, loop, iff, ddepth);
3002
3003 IfNode* dum_if = new IfNode(reg, short_circuit_if(nullptr, proj), iff->_prob, iff->_fcnt);
3004 register_node(dum_if, loop, reg, ddepth);
3005
3006 proj->set_req(0, dum_if); // reattach
3007 set_idom(proj, dum_if, ddepth);
3008
3009 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
3010 register_node(dum_proj, loop, dum_if, ddepth);
3011
3012 return reg;
3013 }
3014
3015 // Idea
3016 // ----
3017 // Partial Peeling tries to rotate the loop in such a way that it can later be turned into a counted loop. Counted loops
3018 // require a signed loop exit test. When calling this method, we've only found a suitable unsigned test to partial peel
3019 // with. Therefore, we try to split off a signed loop exit test from the unsigned test such that it can be used as new
3020 // loop exit while keeping the unsigned test unchanged and preserving the same behavior as if we've used the unsigned
3021 // test alone instead:
3022 //
3023 // Before Partial Peeling:
3024 // Loop:
3025 // <peeled section>
3026 // Split off signed loop exit test
3027 // <-- CUT HERE -->
3028 // Unchanged unsigned loop exit test
3029 // <rest of unpeeled section>
3030 // goto Loop
3031 //
3032 // After Partial Peeling:
3033 // <cloned peeled section>
3034 // Cloned split off signed loop exit test
3035 // Loop:
3036 // Unchanged unsigned loop exit test
3037 // <rest of unpeeled section>
3038 // <peeled section>
3039 // Split off signed loop exit test
3040 // goto Loop
3041 //
3042 // Details
3043 // -------
3044 // Before:
3045 // if (i <u limit) Unsigned loop exit condition
3046 // / |
3047 // v v
3048 // exit-proj stay-in-loop-proj
3049 //
3050 // Split off a signed loop exit test (i.e. with CmpI) from an unsigned loop exit test (i.e. with CmpU) and insert it
3051 // before the CmpU on the stay-in-loop path and keep both tests:
3052 //
3053 // if (i <u limit) Signed loop exit test
3054 // / |
3055 // / if (i <u limit) Unsigned loop exit test
3056 // / / |
3057 // v v v
3058 // exit-region stay-in-loop-proj
3059 //
3060 // Implementation
3061 // --------------
3062 // We need to make sure that the new signed loop exit test is properly inserted into the graph such that the unsigned
3063 // loop exit test still dominates the same set of control nodes, the ctrl() relation from data nodes to both loop
3064 // exit tests is preserved, and their loop nesting is correct.
3065 //
3066 // To achieve that, we clone the unsigned loop exit test completely (leave it unchanged), insert the signed loop exit
3067 // test above it and kill the original unsigned loop exit test by setting it's condition to a constant
3068 // (i.e. stay-in-loop-const in graph below) such that IGVN can fold it later:
3069 //
3070 // if (stay-in-loop-const) Killed original unsigned loop exit test
3071 // / |
3072 // / v
3073 // / if (i < limit) Split off signed loop exit test
3074 // / / |
3075 // / / v
3076 // / / if (i <u limit) Cloned unsigned loop exit test
3077 // / / / |
3078 // v v v |
3079 // exit-region |
3080 // | |
3081 // dummy-if |
3082 // / | |
3083 // dead | |
3084 // v v
3085 // exit-proj stay-in-loop-proj
3086 //
3087 // Note: The dummy-if is inserted to create a region to merge the loop exits between the original to be killed unsigned
3088 // loop exit test and its exit projection while keeping the exit projection (also see insert_region_before_proj()).
3089 //
3090 // Requirements
3091 // ------------
3092 // Note that we can only split off a signed loop exit test from the unsigned loop exit test when the behavior is exactly
3093 // the same as before with only a single unsigned test. This is only possible if certain requirements are met.
3094 // Otherwise, we need to bail out (see comments in the code below).
3095 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree* loop) {
3096 const bool Signed = true;
3097 const bool Unsigned = false;
3098
3099 BoolNode* bol = if_cmpu->in(1)->as_Bool();
3100 if (bol->_test._test != BoolTest::lt) {
3101 return nullptr;
3102 }
3103 CmpNode* cmpu = bol->in(1)->as_Cmp();
3104 assert(cmpu->Opcode() == Op_CmpU, "must be unsigned comparison");
3105
3106 int stride = stride_of_possible_iv(if_cmpu);
3107 if (stride == 0) {
3108 return nullptr;
3109 }
3110
3111 Node* lp_proj = stay_in_loop(if_cmpu, loop);
3112 guarantee(lp_proj != nullptr, "null loop node");
3113
3114 ProjNode* lp_continue = lp_proj->as_Proj();
3115 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
3116 if (!lp_exit->is_IfFalse()) {
3117 // The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit).
3118 // We therefore can't add a single exit condition.
3119 return nullptr;
3120 }
3121 // The unsigned loop exit condition is
3122 // !(i <u limit)
3123 // = i >=u limit
3124 //
3125 // First, we note that for any x for which
3126 // 0 <= x <= INT_MAX
3127 // we can convert x to an unsigned int and still get the same guarantee:
3128 // 0 <= (uint) x <= INT_MAX = (uint) INT_MAX
3129 // 0 <=u (uint) x <=u INT_MAX = (uint) INT_MAX (LEMMA)
3130 //
3131 // With that in mind, if
3132 // limit >= 0 (COND)
3133 // then the unsigned loop exit condition
3134 // i >=u limit (ULE)
3135 // is equivalent to
3136 // i < 0 || i >= limit (SLE-full)
3137 // because either i is negative and therefore always greater than MAX_INT when converting to unsigned
3138 // (uint) i >=u MAX_INT >= limit >= 0
3139 // or otherwise
3140 // i >= limit >= 0
3141 // holds due to (LEMMA).
3142 //
3143 // For completeness, a counterexample with limit < 0:
3144 // Assume i = -3 and limit = -2:
3145 // i < 0
3146 // -2 < 0
3147 // is true and thus also "i < 0 || i >= limit". But
3148 // i >=u limit
3149 // -3 >=u -2
3150 // is false.
3151 Node* limit = cmpu->in(2);
3152 const TypeInt* type_limit = _igvn.type(limit)->is_int();
3153 if (type_limit->_lo < 0) {
3154 return nullptr;
3155 }
3156
3157 // We prove below that we can extract a single signed loop exit condition from (SLE-full), depending on the stride:
3158 // stride < 0:
3159 // i < 0 (SLE = SLE-negative)
3160 // stride > 0:
3161 // i >= limit (SLE = SLE-positive)
3162 // such that we have the following graph before Partial Peeling with stride > 0 (similar for stride < 0):
3163 //
3164 // Loop:
3165 // <peeled section>
3166 // i >= limit (SLE-positive)
3167 // <-- CUT HERE -->
3168 // i >=u limit (ULE)
3169 // <rest of unpeeled section>
3170 // goto Loop
3171 //
3172 // We exit the loop if:
3173 // (SLE) is true OR (ULE) is true
3174 // However, if (SLE) is true then (ULE) also needs to be true to ensure the exact same behavior. Otherwise, we wrongly
3175 // exit a loop that should not have been exited if we did not apply Partial Peeling. More formally, we need to ensure:
3176 // (SLE) IMPLIES (ULE)
3177 // This indeed holds when (COND) is given:
3178 // - stride > 0:
3179 // i >= limit // (SLE = SLE-positive)
3180 // i >= limit >= 0 // (COND)
3181 // i >=u limit >= 0 // (LEMMA)
3182 // which is the unsigned loop exit condition (ULE).
3183 // - stride < 0:
3184 // i < 0 // (SLE = SLE-negative)
3185 // (uint) i >u MAX_INT // (NEG) all negative values are greater than MAX_INT when converted to unsigned
3186 // MAX_INT >= limit >= 0 // (COND)
3187 // MAX_INT >=u limit >= 0 // (LEMMA)
3188 // and thus from (NEG) and (LEMMA):
3189 // i >=u limit
3190 // which is the unsigned loop exit condition (ULE).
3191 //
3192 //
3193 // After Partial Peeling, we have the following structure for stride > 0 (similar for stride < 0):
3194 // <cloned peeled section>
3195 // i >= limit (SLE-positive)
3196 // Loop:
3197 // i >=u limit (ULE)
3198 // <rest of unpeeled section>
3199 // <peeled section>
3200 // i >= limit (SLE-positive)
3201 // goto Loop
3202 Node* rhs_cmpi;
3203 if (stride > 0) {
3204 rhs_cmpi = limit; // For i >= limit
3205 } else {
3206 rhs_cmpi = makecon(TypeInt::ZERO); // For i < 0
3207 }
3208 // Create a new region on the exit path
3209 RegionNode* reg = insert_region_before_proj(lp_exit);
3210 guarantee(reg != nullptr, "null region node");
3211
3212 // Clone the if-cmpu-true-false using a signed compare
3213 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
3214 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, rhs_cmpi, lp_continue);
3215 reg->add_req(cmpi_exit);
3216
3217 // Clone the if-cmpu-true-false
3218 BoolTest::mask rel_u = bol->_test._test;
3219 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
3220 reg->add_req(cmpu_exit);
3221
3222 // Force original if to stay in loop.
3223 short_circuit_if(if_cmpu, lp_continue);
3224
3225 return cmpi_exit->in(0)->as_If();
3226 }
3227
3228 //------------------------------ remove_cmpi_loop_exit -------------------------------------
3229 // Remove a previously inserted signed compare loop exit.
3230 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
3231 Node* lp_proj = stay_in_loop(if_cmp, loop);
3232 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
3233 stay_in_loop(lp_proj, loop)->is_If() &&
3234 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
3235 Node* con = makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
3236 if_cmp->set_req(1, con);
3237 }
3238
3239 //------------------------------ scheduled_nodelist -------------------------------------
3240 // Create a post order schedule of nodes that are in the
3241 // "member" set. The list is returned in "sched".
3242 // The first node in "sched" is the loop head, followed by
3243 // nodes which have no inputs in the "member" set, and then
3244 // followed by the nodes that have an immediate input dependence
3245 // on a node in "sched".
3246 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
3247
3248 assert(member.test(loop->_head->_idx), "loop head must be in member set");
3249 VectorSet visited;
3250 Node_Stack nstack(loop->_body.size());
3251
3252 Node* n = loop->_head; // top of stack is cached in "n"
3253 uint idx = 0;
3254 visited.set(n->_idx);
3255
3256 // Initially push all with no inputs from within member set
3257 for(uint i = 0; i < loop->_body.size(); i++ ) {
3258 Node *elt = loop->_body.at(i);
3259 if (member.test(elt->_idx)) {
3260 bool found = false;
3261 for (uint j = 0; j < elt->req(); j++) {
3262 Node* def = elt->in(j);
3263 if (def && member.test(def->_idx) && def != elt) {
3264 found = true;
3265 break;
3266 }
3267 }
3268 if (!found && elt != loop->_head) {
3269 nstack.push(n, idx);
3270 n = elt;
3271 assert(!visited.test(n->_idx), "not seen yet");
3272 visited.set(n->_idx);
3273 }
3274 }
3275 }
3276
3277 // traverse out's that are in the member set
3278 while (true) {
3279 if (idx < n->outcnt()) {
3280 Node* use = n->raw_out(idx);
3281 idx++;
3282 if (!visited.test_set(use->_idx)) {
3283 if (member.test(use->_idx)) {
3284 nstack.push(n, idx);
3285 n = use;
3286 idx = 0;
3287 }
3288 }
3289 } else {
3290 // All outputs processed
3291 sched.push(n);
3292 if (nstack.is_empty()) break;
3293 n = nstack.node();
3294 idx = nstack.index();
3295 nstack.pop();
3296 }
3297 }
3298 }
3299
3300
3301 //------------------------------ has_use_in_set -------------------------------------
3302 // Has a use in the vector set
3303 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
3304 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3305 Node* use = n->fast_out(j);
3306 if (vset.test(use->_idx)) {
3307 return true;
3308 }
3309 }
3310 return false;
3311 }
3312
3313
3314 //------------------------------ has_use_internal_to_set -------------------------------------
3315 // Has use internal to the vector set (ie. not in a phi at the loop head)
3316 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
3317 Node* head = loop->_head;
3318 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3319 Node* use = n->fast_out(j);
3320 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
3321 return true;
3322 }
3323 }
3324 return false;
3325 }
3326
3327
3328 //------------------------------ clone_for_use_outside_loop -------------------------------------
3329 // clone "n" for uses that are outside of loop
3330 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
3331 int cloned = 0;
3332 assert(worklist.size() == 0, "should be empty");
3333 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3334 Node* use = n->fast_out(j);
3335 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
3336 worklist.push(use);
3337 }
3338 }
3339
3340 if (C->check_node_count(worklist.size() + NodeLimitFudgeFactor,
3341 "Too many clones required in clone_for_use_outside_loop in partial peeling")) {
3342 return -1;
3343 }
3344
3345 while( worklist.size() ) {
3346 Node *use = worklist.pop();
3347 if (!has_node(use) || use->in(0) == C->top()) continue;
3348 uint j;
3349 for (j = 0; j < use->req(); j++) {
3350 if (use->in(j) == n) break;
3351 }
3352 assert(j < use->req(), "must be there");
3353
3354 // clone "n" and insert it between the inputs of "n" and the use outside the loop
3355 Node* n_clone = n->clone();
3356 _igvn.replace_input_of(use, j, n_clone);
3357 cloned++;
3358 Node* use_c;
3359 if (!use->is_Phi()) {
3360 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
3361 } else {
3362 // Use in a phi is considered a use in the associated predecessor block
3363 use_c = use->in(0)->in(j);
3364 }
3365 set_ctrl(n_clone, use_c);
3366 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
3367 get_loop(use_c)->_body.push(n_clone);
3368 _igvn.register_new_node_with_optimizer(n_clone);
3369 #ifndef PRODUCT
3370 if (TracePartialPeeling) {
3371 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
3372 }
3373 #endif
3374 }
3375 return cloned;
3376 }
3377
3378
3379 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
3380 // clone "n" for special uses that are in the not_peeled region.
3381 // If these def-uses occur in separate blocks, the code generator
3382 // marks the method as not compilable. For example, if a "BoolNode"
3383 // is in a different basic block than the "IfNode" that uses it, then
3384 // the compilation is aborted in the code generator.
3385 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
3386 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
3387 if (n->is_Phi() || n->is_Load()) {
3388 return;
3389 }
3390 assert(worklist.size() == 0, "should be empty");
3391 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3392 Node* use = n->fast_out(j);
3393 if ( not_peel.test(use->_idx) &&
3394 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
3395 use->in(1) == n) {
3396 worklist.push(use);
3397 }
3398 }
3399 if (worklist.size() > 0) {
3400 // clone "n" and insert it between inputs of "n" and the use
3401 Node* n_clone = n->clone();
3402 loop->_body.push(n_clone);
3403 _igvn.register_new_node_with_optimizer(n_clone);
3404 set_ctrl(n_clone, get_ctrl(n));
3405 sink_list.push(n_clone);
3406 not_peel.set(n_clone->_idx);
3407 #ifndef PRODUCT
3408 if (TracePartialPeeling) {
3409 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
3410 }
3411 #endif
3412 while( worklist.size() ) {
3413 Node *use = worklist.pop();
3414 _igvn.rehash_node_delayed(use);
3415 for (uint j = 1; j < use->req(); j++) {
3416 if (use->in(j) == n) {
3417 use->set_req(j, n_clone);
3418 }
3419 }
3420 }
3421 }
3422 }
3423
3424
3425 //------------------------------ insert_phi_for_loop -------------------------------------
3426 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
3427 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
3428 Node *phi = PhiNode::make(lp, back_edge_val);
3429 phi->set_req(LoopNode::EntryControl, lp_entry_val);
3430 // Use existing phi if it already exists
3431 Node *hit = _igvn.hash_find_insert(phi);
3432 if( hit == nullptr ) {
3433 _igvn.register_new_node_with_optimizer(phi);
3434 set_ctrl(phi, lp);
3435 } else {
3436 // Remove the new phi from the graph and use the hit
3437 _igvn.remove_dead_node(phi);
3438 phi = hit;
3439 }
3440 _igvn.replace_input_of(use, idx, phi);
3441 }
3442
3443 #ifdef ASSERT
3444 //------------------------------ is_valid_loop_partition -------------------------------------
3445 // Validate the loop partition sets: peel and not_peel
3446 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
3447 VectorSet& not_peel ) {
3448 uint i;
3449 // Check that peel_list entries are in the peel set
3450 for (i = 0; i < peel_list.size(); i++) {
3451 if (!peel.test(peel_list.at(i)->_idx)) {
3452 return false;
3453 }
3454 }
3455 // Check at loop members are in one of peel set or not_peel set
3456 for (i = 0; i < loop->_body.size(); i++ ) {
3457 Node *def = loop->_body.at(i);
3458 uint di = def->_idx;
3459 // Check that peel set elements are in peel_list
3460 if (peel.test(di)) {
3461 if (not_peel.test(di)) {
3462 return false;
3463 }
3464 // Must be in peel_list also
3465 bool found = false;
3466 for (uint j = 0; j < peel_list.size(); j++) {
3467 if (peel_list.at(j)->_idx == di) {
3468 found = true;
3469 break;
3470 }
3471 }
3472 if (!found) {
3473 return false;
3474 }
3475 } else if (not_peel.test(di)) {
3476 if (peel.test(di)) {
3477 return false;
3478 }
3479 } else {
3480 return false;
3481 }
3482 }
3483 return true;
3484 }
3485
3486 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
3487 // Ensure a use outside of loop is of the right form
3488 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
3489 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3490 return (use->is_Phi() &&
3491 use_c->is_Region() && use_c->req() == 3 &&
3492 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
3493 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
3494 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
3495 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
3496 }
3497
3498 //------------------------------ is_valid_clone_loop_form -------------------------------------
3499 // Ensure that all uses outside of loop are of the right form
3500 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
3501 uint orig_exit_idx, uint clone_exit_idx) {
3502 uint len = peel_list.size();
3503 for (uint i = 0; i < len; i++) {
3504 Node *def = peel_list.at(i);
3505
3506 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3507 Node *use = def->fast_out(j);
3508 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3509 if (!loop->is_member(get_loop(use_c))) {
3510 // use is not in the loop, check for correct structure
3511 if (use->in(0) == def) {
3512 // Okay
3513 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
3514 return false;
3515 }
3516 }
3517 }
3518 }
3519 return true;
3520 }
3521 #endif
3522
3523 //------------------------------ partial_peel -------------------------------------
3524 // Partially peel (aka loop rotation) the top portion of a loop (called
3525 // the peel section below) by cloning it and placing one copy just before
3526 // the new loop head and the other copy at the bottom of the new loop.
3527 //
3528 // before after where it came from
3529 //
3530 // stmt1 stmt1
3531 // loop: stmt2 clone
3532 // stmt2 if condA goto exitA clone
3533 // if condA goto exitA new_loop: new
3534 // stmt3 stmt3 clone
3535 // if !condB goto loop if condB goto exitB clone
3536 // exitB: stmt2 orig
3537 // stmt4 if !condA goto new_loop orig
3538 // exitA: goto exitA
3539 // exitB:
3540 // stmt4
3541 // exitA:
3542 //
3543 // Step 1: find the cut point: an exit test on probable
3544 // induction variable.
3545 // Step 2: schedule (with cloning) operations in the peel
3546 // section that can be executed after the cut into
3547 // the section that is not peeled. This may need
3548 // to clone operations into exit blocks. For
3549 // instance, a reference to A[i] in the not-peel
3550 // section and a reference to B[i] in an exit block
3551 // may cause a left-shift of i by 2 to be placed
3552 // in the peel block. This step will clone the left
3553 // shift into the exit block and sink the left shift
3554 // from the peel to the not-peel section.
3555 // Step 3: clone the loop, retarget the control, and insert
3556 // phis for values that are live across the new loop
3557 // head. This is very dependent on the graph structure
3558 // from clone_loop. It creates region nodes for
3559 // exit control and associated phi nodes for values
3560 // flow out of the loop through that exit. The region
3561 // node is dominated by the clone's control projection.
3562 // So the clone's peel section is placed before the
3563 // new loop head, and the clone's not-peel section is
3564 // forms the top part of the new loop. The original
3565 // peel section forms the tail of the new loop.
3566 // Step 4: update the dominator tree and recompute the
3567 // dominator depth.
3568 //
3569 // orig
3570 //
3571 // stmt1
3572 // |
3573 // v
3574 // predicates
3575 // |
3576 // v
3577 // loop<----+
3578 // | |
3579 // stmt2 |
3580 // | |
3581 // v |
3582 // ifA |
3583 // / | |
3584 // v v |
3585 // false true ^ <-- last_peel
3586 // / | |
3587 // / ===|==cut |
3588 // / stmt3 | <-- first_not_peel
3589 // / | |
3590 // | v |
3591 // v ifB |
3592 // exitA: / \ |
3593 // / \ |
3594 // v v |
3595 // false true |
3596 // / \ |
3597 // / ----+
3598 // |
3599 // v
3600 // exitB:
3601 // stmt4
3602 //
3603 //
3604 // after clone loop
3605 //
3606 // stmt1
3607 // |
3608 // v
3609 // predicates
3610 // / \
3611 // clone / \ orig
3612 // / \
3613 // / \
3614 // v v
3615 // +---->loop loop<----+
3616 // | | | |
3617 // | stmt2 stmt2 |
3618 // | | | |
3619 // | v v |
3620 // | ifA ifA |
3621 // | | \ / | |
3622 // | v v v v |
3623 // ^ true false false true ^ <-- last_peel
3624 // | | ^ \ / | |
3625 // | cut==|== \ \ / ===|==cut |
3626 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3627 // | | dom | | | |
3628 // | v \ 1v v2 v |
3629 // | ifB regionA ifB |
3630 // | / \ | / \ |
3631 // | / \ v / \ |
3632 // | v v exitA: v v |
3633 // | true false false true |
3634 // | / ^ \ / \ |
3635 // +---- \ \ / ----+
3636 // dom \ /
3637 // \ 1v v2
3638 // regionB
3639 // |
3640 // v
3641 // exitB:
3642 // stmt4
3643 //
3644 //
3645 // after partial peel
3646 //
3647 // stmt1
3648 // |
3649 // v
3650 // predicates
3651 // /
3652 // clone / orig
3653 // / TOP
3654 // / \
3655 // v v
3656 // TOP->loop loop----+
3657 // | | |
3658 // stmt2 stmt2 |
3659 // | | |
3660 // v v |
3661 // ifA ifA |
3662 // | \ / | |
3663 // v v v v |
3664 // true false false true | <-- last_peel
3665 // | ^ \ / +------|---+
3666 // +->newloop \ \ / === ==cut | |
3667 // | stmt3 \ \ / TOP | |
3668 // | | dom | | stmt3 | | <-- first_not_peel
3669 // | v \ 1v v2 v | |
3670 // | ifB regionA ifB ^ v
3671 // | / \ | / \ | |
3672 // | / \ v / \ | |
3673 // | v v exitA: v v | |
3674 // | true false false true | |
3675 // | / ^ \ / \ | |
3676 // | | \ \ / v | |
3677 // | | dom \ / TOP | |
3678 // | | \ 1v v2 | |
3679 // ^ v regionB | |
3680 // | | | | |
3681 // | | v ^ v
3682 // | | exitB: | |
3683 // | | stmt4 | |
3684 // | +------------>-----------------+ |
3685 // | |
3686 // +-----------------<---------------------+
3687 //
3688 //
3689 // final graph
3690 //
3691 // stmt1
3692 // |
3693 // v
3694 // predicates
3695 // |
3696 // v
3697 // stmt2 clone
3698 // |
3699 // v
3700 // ........> ifA clone
3701 // : / |
3702 // dom / |
3703 // : v v
3704 // : false true
3705 // : | |
3706 // : | v
3707 // : | newloop<-----+
3708 // : | | |
3709 // : | stmt3 clone |
3710 // : | | |
3711 // : | v |
3712 // : | ifB |
3713 // : | / \ |
3714 // : | v v |
3715 // : | false true |
3716 // : | | | |
3717 // : | v stmt2 |
3718 // : | exitB: | |
3719 // : | stmt4 v |
3720 // : | ifA orig |
3721 // : | / \ |
3722 // : | / \ |
3723 // : | v v |
3724 // : | false true |
3725 // : | / \ |
3726 // : v v -----+
3727 // RegionA
3728 // |
3729 // v
3730 // exitA
3731 //
3732 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3733
3734 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3735 if (!loop->_head->is_Loop()) {
3736 return false;
3737 }
3738 LoopNode *head = loop->_head->as_Loop();
3739
3740 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3741 return false;
3742 }
3743
3744 // Check for complex exit control
3745 for (uint ii = 0; ii < loop->_body.size(); ii++) {
3746 Node *n = loop->_body.at(ii);
3747 int opc = n->Opcode();
3748 if (n->is_Call() ||
3749 opc == Op_Catch ||
3750 opc == Op_CatchProj ||
3751 opc == Op_Jump ||
3752 opc == Op_JumpProj) {
3753 #ifndef PRODUCT
3754 if (TracePartialPeeling) {
3755 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3756 }
3757 #endif
3758 return false;
3759 }
3760 }
3761
3762 int dd = dom_depth(head);
3763
3764 // Step 1: find cut point
3765
3766 // Walk up dominators to loop head looking for first loop exit
3767 // which is executed on every path thru loop.
3768 IfNode *peel_if = nullptr;
3769 IfNode *peel_if_cmpu = nullptr;
3770
3771 Node *iff = loop->tail();
3772 while (iff != head) {
3773 if (iff->is_If()) {
3774 Node *ctrl = get_ctrl(iff->in(1));
3775 if (ctrl->is_top()) return false; // Dead test on live IF.
3776 // If loop-varying exit-test, check for induction variable
3777 if (loop->is_member(get_loop(ctrl)) &&
3778 loop->is_loop_exit(iff) &&
3779 is_possible_iv_test(iff)) {
3780 Node* cmp = iff->in(1)->in(1);
3781 if (cmp->Opcode() == Op_CmpI) {
3782 peel_if = iff->as_If();
3783 } else {
3784 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3785 peel_if_cmpu = iff->as_If();
3786 }
3787 }
3788 }
3789 iff = idom(iff);
3790 }
3791
3792 // Prefer signed compare over unsigned compare.
3793 IfNode* new_peel_if = nullptr;
3794 if (peel_if == nullptr) {
3795 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == nullptr) {
3796 return false; // No peel point found
3797 }
3798 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3799 if (new_peel_if == nullptr) {
3800 return false; // No peel point found
3801 }
3802 peel_if = new_peel_if;
3803 }
3804 Node* last_peel = stay_in_loop(peel_if, loop);
3805 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3806 if (first_not_peeled == nullptr || first_not_peeled == head) {
3807 return false;
3808 }
3809
3810 #ifndef PRODUCT
3811 if (TraceLoopOpts) {
3812 tty->print("PartialPeel ");
3813 loop->dump_head();
3814 }
3815
3816 if (TracePartialPeeling) {
3817 tty->print_cr("before partial peel one iteration");
3818 Node_List wl;
3819 Node* t = head->in(2);
3820 while (true) {
3821 wl.push(t);
3822 if (t == head) break;
3823 t = idom(t);
3824 }
3825 while (wl.size() > 0) {
3826 Node* tt = wl.pop();
3827 tt->dump();
3828 if (tt == last_peel) tty->print_cr("-- cut --");
3829 }
3830 }
3831 #endif
3832
3833 C->print_method(PHASE_BEFORE_PARTIAL_PEELING, 4, head);
3834
3835 VectorSet peel;
3836 VectorSet not_peel;
3837 Node_List peel_list;
3838 Node_List worklist;
3839 Node_List sink_list;
3840
3841 uint estimate = loop->est_loop_clone_sz(1);
3842 if (exceeding_node_budget(estimate)) {
3843 return false;
3844 }
3845
3846 // Set of cfg nodes to peel are those that are executable from
3847 // the head through last_peel.
3848 assert(worklist.size() == 0, "should be empty");
3849 worklist.push(head);
3850 peel.set(head->_idx);
3851 while (worklist.size() > 0) {
3852 Node *n = worklist.pop();
3853 if (n != last_peel) {
3854 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3855 Node* use = n->fast_out(j);
3856 if (use->is_CFG() &&
3857 loop->is_member(get_loop(use)) &&
3858 !peel.test_set(use->_idx)) {
3859 worklist.push(use);
3860 }
3861 }
3862 }
3863 }
3864
3865 // Set of non-cfg nodes to peel are those that are control
3866 // dependent on the cfg nodes.
3867 for (uint i = 0; i < loop->_body.size(); i++) {
3868 Node *n = loop->_body.at(i);
3869 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3870 if (peel.test(n_c->_idx)) {
3871 peel.set(n->_idx);
3872 } else {
3873 not_peel.set(n->_idx);
3874 }
3875 }
3876
3877 // Step 2: move operations from the peeled section down into the
3878 // not-peeled section
3879
3880 // Get a post order schedule of nodes in the peel region
3881 // Result in right-most operand.
3882 scheduled_nodelist(loop, peel, peel_list);
3883
3884 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3885
3886 // For future check for too many new phis
3887 uint old_phi_cnt = 0;
3888 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3889 Node* use = head->fast_out(j);
3890 if (use->is_Phi()) old_phi_cnt++;
3891 }
3892
3893 #ifndef PRODUCT
3894 if (TracePartialPeeling) {
3895 tty->print_cr("\npeeled list");
3896 }
3897 #endif
3898
3899 // Evacuate nodes in peel region into the not_peeled region if possible
3900 bool too_many_clones = false;
3901 uint new_phi_cnt = 0;
3902 uint cloned_for_outside_use = 0;
3903 for (uint i = 0; i < peel_list.size();) {
3904 Node* n = peel_list.at(i);
3905 #ifndef PRODUCT
3906 if (TracePartialPeeling) n->dump();
3907 #endif
3908 bool incr = true;
3909 if (!n->is_CFG()) {
3910 if (has_use_in_set(n, not_peel)) {
3911 // If not used internal to the peeled region,
3912 // move "n" from peeled to not_peeled region.
3913 if (!has_use_internal_to_set(n, peel, loop)) {
3914 // if not pinned and not a load (which maybe anti-dependent on a store)
3915 // and not a CMove (Matcher expects only bool->cmove).
3916 if (n->in(0) == nullptr && !n->is_Load() && !n->is_CMove()) {
3917 int new_clones = clone_for_use_outside_loop(loop, n, worklist);
3918 if (C->failing()) return false;
3919 if (new_clones == -1) {
3920 too_many_clones = true;
3921 break;
3922 }
3923 cloned_for_outside_use += new_clones;
3924 sink_list.push(n);
3925 peel.remove(n->_idx);
3926 not_peel.set(n->_idx);
3927 peel_list.remove(i);
3928 incr = false;
3929 #ifndef PRODUCT
3930 if (TracePartialPeeling) {
3931 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3932 n->_idx, get_ctrl(n)->_idx);
3933 }
3934 #endif
3935 }
3936 } else {
3937 // Otherwise check for special def-use cases that span
3938 // the peel/not_peel boundary such as bool->if
3939 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist);
3940 new_phi_cnt++;
3941 }
3942 }
3943 }
3944 if (incr) i++;
3945 }
3946
3947 estimate += cloned_for_outside_use + new_phi_cnt;
3948 bool exceed_node_budget = !may_require_nodes(estimate);
3949 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta;
3950
3951 if (too_many_clones || exceed_node_budget || exceed_phi_limit) {
3952 #ifndef PRODUCT
3953 if (TracePartialPeeling && exceed_phi_limit) {
3954 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3955 new_phi_cnt, old_phi_cnt, new_peel_if != nullptr?'T':'F');
3956 }
3957 #endif
3958 if (new_peel_if != nullptr) {
3959 remove_cmpi_loop_exit(new_peel_if, loop);
3960 }
3961 // Inhibit more partial peeling on this loop
3962 assert(!head->is_partial_peel_loop(), "not partial peeled");
3963 head->mark_partial_peel_failed();
3964 if (cloned_for_outside_use > 0) {
3965 // Terminate this round of loop opts because
3966 // the graph outside this loop was changed.
3967 C->set_major_progress();
3968 return true;
3969 }
3970 return false;
3971 }
3972
3973 // Step 3: clone loop, retarget control, and insert new phis
3974
3975 // Create new loop head for new phis and to hang
3976 // the nodes being moved (sinked) from the peel region.
3977 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3978 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3979 _igvn.register_new_node_with_optimizer(new_head);
3980 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3981 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3982 set_loop(new_head, loop);
3983 loop->_body.push(new_head);
3984 not_peel.set(new_head->_idx);
3985 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3986 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3987
3988 while (sink_list.size() > 0) {
3989 Node* n = sink_list.pop();
3990 set_ctrl(n, new_head);
3991 }
3992
3993 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3994
3995 clone_loop(loop, old_new, dd, IgnoreStripMined);
3996
3997 const uint clone_exit_idx = 1;
3998 const uint orig_exit_idx = 2;
3999 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop");
4000
4001 Node* head_clone = old_new[head->_idx];
4002 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
4003 Node* orig_tail_clone = head_clone->in(2);
4004
4005 // Add phi if "def" node is in peel set and "use" is not
4006
4007 for (uint i = 0; i < peel_list.size(); i++) {
4008 Node *def = peel_list.at(i);
4009 if (!def->is_CFG()) {
4010 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
4011 Node *use = def->fast_out(j);
4012 if (has_node(use) && use->in(0) != C->top() &&
4013 (!peel.test(use->_idx) ||
4014 (use->is_Phi() && use->in(0) == head)) ) {
4015 worklist.push(use);
4016 }
4017 }
4018 while( worklist.size() ) {
4019 Node *use = worklist.pop();
4020 for (uint j = 1; j < use->req(); j++) {
4021 Node* n = use->in(j);
4022 if (n == def) {
4023
4024 // "def" is in peel set, "use" is not in peel set
4025 // or "use" is in the entry boundary (a phi) of the peel set
4026
4027 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
4028
4029 if ( loop->is_member(get_loop( use_c )) ) {
4030 // use is in loop
4031 if (old_new[use->_idx] != nullptr) { // null for dead code
4032 Node* use_clone = old_new[use->_idx];
4033 _igvn.replace_input_of(use, j, C->top());
4034 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
4035 }
4036 } else {
4037 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
4038 // use is not in the loop, check if the live range includes the cut
4039 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
4040 if (not_peel.test(lp_if->_idx)) {
4041 assert(j == orig_exit_idx, "use from original loop");
4042 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
4043 }
4044 }
4045 }
4046 }
4047 }
4048 }
4049 }
4050
4051 // Step 3b: retarget control
4052
4053 // Redirect control to the new loop head if a cloned node in
4054 // the not_peeled region has control that points into the peeled region.
4055 // This necessary because the cloned peeled region will be outside
4056 // the loop.
4057 // from to
4058 // cloned-peeled <---+
4059 // new_head_clone: | <--+
4060 // cloned-not_peeled in(0) in(0)
4061 // orig-peeled
4062
4063 for (uint i = 0; i < loop->_body.size(); i++) {
4064 Node *n = loop->_body.at(i);
4065 if (!n->is_CFG() && n->in(0) != nullptr &&
4066 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
4067 Node* n_clone = old_new[n->_idx];
4068 if (n_clone->depends_only_on_test()) {
4069 // Pin array access nodes: control is updated here to the loop head. If, after some transformations, the
4070 // backedge is removed, an array load could become dependent on a condition that's not a range check for that
4071 // access. If that condition is replaced by an identical dominating one, then an unpinned load would risk
4072 // floating above its range check.
4073 Node* pinned_clone = n_clone->pin_array_access_node();
4074 if (pinned_clone != nullptr) {
4075 register_new_node_with_ctrl_of(pinned_clone, n_clone);
4076 old_new.map(n->_idx, pinned_clone);
4077 _igvn.replace_node(n_clone, pinned_clone);
4078 n_clone = pinned_clone;
4079 }
4080 }
4081 _igvn.replace_input_of(n_clone, 0, new_head_clone);
4082 }
4083 }
4084
4085 // Backedge of the surviving new_head (the clone) is original last_peel
4086 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
4087
4088 // Cut first node in original not_peel set
4089 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
4090 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
4091 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
4092
4093 // Copy head_clone back-branch info to original head
4094 // and remove original head's loop entry and
4095 // clone head's back-branch
4096 _igvn.rehash_node_delayed(head); // Multiple edge updates
4097 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
4098 head->set_req(LoopNode::LoopBackControl, C->top());
4099 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
4100
4101 // Similarly modify the phis
4102 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
4103 Node* use = head->fast_out(k);
4104 if (use->is_Phi() && use->outcnt() > 0) {
4105 Node* use_clone = old_new[use->_idx];
4106 _igvn.rehash_node_delayed(use); // Multiple edge updates
4107 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
4108 use->set_req(LoopNode::LoopBackControl, C->top());
4109 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
4110 }
4111 }
4112
4113 // Step 4: update dominator tree and dominator depth
4114
4115 set_idom(head, orig_tail_clone, dd);
4116 recompute_dom_depth();
4117
4118 // Inhibit more partial peeling on this loop
4119 new_head_clone->set_partial_peel_loop();
4120 C->set_major_progress();
4121 loop->record_for_igvn();
4122
4123 #ifndef PRODUCT
4124 if (TracePartialPeeling) {
4125 tty->print_cr("\nafter partial peel one iteration");
4126 Node_List wl;
4127 Node* t = last_peel;
4128 while (true) {
4129 wl.push(t);
4130 if (t == head_clone) break;
4131 t = idom(t);
4132 }
4133 while (wl.size() > 0) {
4134 Node* tt = wl.pop();
4135 if (tt == head) tty->print_cr("orig head");
4136 else if (tt == new_head_clone) tty->print_cr("new head");
4137 else if (tt == head_clone) tty->print_cr("clone head");
4138 tt->dump();
4139 }
4140 }
4141 #endif
4142
4143 C->print_method(PHASE_AFTER_PARTIAL_PEELING, 4, new_head_clone);
4144
4145 return true;
4146 }
4147
4148 // Transform:
4149 //
4150 // loop<-----------------+
4151 // | |
4152 // stmt1 stmt2 .. stmtn |
4153 // | | | |
4154 // \ | / |
4155 // v v v |
4156 // region |
4157 // | |
4158 // shared_stmt |
4159 // | |
4160 // v |
4161 // if |
4162 // / \ |
4163 // | -----------+
4164 // v
4165 //
4166 // into:
4167 //
4168 // loop<-------------------+
4169 // | |
4170 // v |
4171 // +->loop |
4172 // | | |
4173 // | stmt1 stmt2 .. stmtn |
4174 // | | | | |
4175 // | | \ / |
4176 // | | v v |
4177 // | | region1 |
4178 // | | | |
4179 // | shared_stmt shared_stmt |
4180 // | | | |
4181 // | v v |
4182 // | if if |
4183 // | /\ / \ |
4184 // +-- | | -------+
4185 // \ /
4186 // v v
4187 // region2
4188 //
4189 // (region2 is shown to merge mirrored projections of the loop exit
4190 // ifs to make the diagram clearer but they really merge the same
4191 // projection)
4192 //
4193 // Conditions for this transformation to trigger:
4194 // - the path through stmt1 is frequent enough
4195 // - the inner loop will be turned into a counted loop after transformation
4196 bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new) {
4197 if (!DuplicateBackedge) {
4198 return false;
4199 }
4200 assert(!loop->_head->is_CountedLoop() || StressDuplicateBackedge, "Non-counted loop only");
4201 if (!loop->_head->is_Loop()) {
4202 return false;
4203 }
4204
4205 uint estimate = loop->est_loop_clone_sz(1);
4206 if (exceeding_node_budget(estimate)) {
4207 return false;
4208 }
4209
4210 LoopNode *head = loop->_head->as_Loop();
4211
4212 Node* region = nullptr;
4213 IfNode* exit_test = nullptr;
4214 uint inner;
4215 float f;
4216 if (StressDuplicateBackedge) {
4217 if (head->is_strip_mined()) {
4218 return false;
4219 }
4220 Node* c = head->in(LoopNode::LoopBackControl);
4221
4222 while (c != head) {
4223 if (c->is_Region()) {
4224 region = c;
4225 }
4226 c = idom(c);
4227 }
4228
4229 if (region == nullptr) {
4230 return false;
4231 }
4232
4233 inner = 1;
4234 } else {
4235 // Is the shape of the loop that of a counted loop...
4236 Node* back_control = loop_exit_control(head, loop);
4237 if (back_control == nullptr) {
4238 return false;
4239 }
4240
4241 BoolTest::mask bt = BoolTest::illegal;
4242 float cl_prob = 0;
4243 Node* incr = nullptr;
4244 Node* limit = nullptr;
4245 Node* cmp = loop_exit_test(back_control, loop, incr, limit, bt, cl_prob);
4246 if (cmp == nullptr || cmp->Opcode() != Op_CmpI) {
4247 return false;
4248 }
4249
4250 // With an extra phi for the candidate iv?
4251 // Or the region node is the loop head
4252 if (!incr->is_Phi() || incr->in(0) == head) {
4253 return false;
4254 }
4255
4256 PathFrequency pf(head, this);
4257 region = incr->in(0);
4258
4259 // Go over all paths for the extra phi's region and see if that
4260 // path is frequent enough and would match the expected iv shape
4261 // if the extra phi is removed
4262 inner = 0;
4263 for (uint i = 1; i < incr->req(); ++i) {
4264 Node* in = incr->in(i);
4265 Node* trunc1 = nullptr;
4266 Node* trunc2 = nullptr;
4267 const TypeInteger* iv_trunc_t = nullptr;
4268 Node* orig_in = in;
4269 if (!(in = CountedLoopNode::match_incr_with_optional_truncation(in, &trunc1, &trunc2, &iv_trunc_t, T_INT))) {
4270 continue;
4271 }
4272 assert(in->Opcode() == Op_AddI, "wrong increment code");
4273 Node* xphi = nullptr;
4274 Node* stride = loop_iv_stride(in, loop, xphi);
4275
4276 if (stride == nullptr) {
4277 continue;
4278 }
4279
4280 PhiNode* phi = loop_iv_phi(xphi, nullptr, head, loop);
4281 if (phi == nullptr ||
4282 (trunc1 == nullptr && phi->in(LoopNode::LoopBackControl) != incr) ||
4283 (trunc1 != nullptr && phi->in(LoopNode::LoopBackControl) != trunc1)) {
4284 return false;
4285 }
4286
4287 f = pf.to(region->in(i));
4288 if (f > 0.5) {
4289 inner = i;
4290 break;
4291 }
4292 }
4293
4294 if (inner == 0) {
4295 return false;
4296 }
4297
4298 exit_test = back_control->in(0)->as_If();
4299 }
4300
4301 if (idom(region)->is_Catch()) {
4302 return false;
4303 }
4304
4305 // Collect all control nodes that need to be cloned (shared_stmt in the diagram)
4306 Unique_Node_List wq;
4307 wq.push(head->in(LoopNode::LoopBackControl));
4308 for (uint i = 0; i < wq.size(); i++) {
4309 Node* c = wq.at(i);
4310 assert(get_loop(c) == loop, "not in the right loop?");
4311 if (c->is_Region()) {
4312 if (c != region) {
4313 for (uint j = 1; j < c->req(); ++j) {
4314 wq.push(c->in(j));
4315 }
4316 }
4317 } else {
4318 wq.push(c->in(0));
4319 }
4320 assert(!is_strict_dominator(c, region), "shouldn't go above region");
4321 }
4322
4323 Node* region_dom = idom(region);
4324
4325 // Can't do the transformation if this would cause a membar pair to
4326 // be split
4327 for (uint i = 0; i < wq.size(); i++) {
4328 Node* c = wq.at(i);
4329 if (c->is_MemBar() && (c->as_MemBar()->trailing_store() || c->as_MemBar()->trailing_load_store())) {
4330 assert(c->as_MemBar()->leading_membar()->trailing_membar() == c, "bad membar pair");
4331 if (!wq.member(c->as_MemBar()->leading_membar())) {
4332 return false;
4333 }
4334 }
4335 }
4336
4337 // Collect data nodes that need to be clones as well
4338 int dd = dom_depth(head);
4339
4340 for (uint i = 0; i < loop->_body.size(); ++i) {
4341 Node* n = loop->_body.at(i);
4342 if (has_ctrl(n)) {
4343 Node* c = get_ctrl(n);
4344 if (wq.member(c)) {
4345 wq.push(n);
4346 }
4347 } else {
4348 set_idom(n, idom(n), dd);
4349 }
4350 }
4351
4352 // clone shared_stmt
4353 clone_loop_body(wq, old_new, nullptr);
4354
4355 Node* region_clone = old_new[region->_idx];
4356 region_clone->set_req(inner, C->top());
4357 set_idom(region, region->in(inner), dd);
4358
4359 // Prepare the outer loop
4360 Node* outer_head = new LoopNode(head->in(LoopNode::EntryControl), old_new[head->in(LoopNode::LoopBackControl)->_idx]);
4361 register_control(outer_head, loop->_parent, outer_head->in(LoopNode::EntryControl));
4362 _igvn.replace_input_of(head, LoopNode::EntryControl, outer_head);
4363 set_idom(head, outer_head, dd);
4364
4365 fix_body_edges(wq, loop, old_new, dd, loop->_parent, true);
4366
4367 // Make one of the shared_stmt copies only reachable from stmt1, the
4368 // other only from stmt2..stmtn.
4369 Node* dom = nullptr;
4370 for (uint i = 1; i < region->req(); ++i) {
4371 if (i != inner) {
4372 _igvn.replace_input_of(region, i, C->top());
4373 }
4374 Node* in = region_clone->in(i);
4375 if (in->is_top()) {
4376 continue;
4377 }
4378 if (dom == nullptr) {
4379 dom = in;
4380 } else {
4381 dom = dom_lca(dom, in);
4382 }
4383 }
4384
4385 set_idom(region_clone, dom, dd);
4386
4387 // Set up the outer loop
4388 for (uint i = 0; i < head->outcnt(); i++) {
4389 Node* u = head->raw_out(i);
4390 if (u->is_Phi()) {
4391 Node* outer_phi = u->clone();
4392 outer_phi->set_req(0, outer_head);
4393 Node* backedge = old_new[u->in(LoopNode::LoopBackControl)->_idx];
4394 if (backedge == nullptr) {
4395 backedge = u->in(LoopNode::LoopBackControl);
4396 }
4397 outer_phi->set_req(LoopNode::LoopBackControl, backedge);
4398 register_new_node(outer_phi, outer_head);
4399 _igvn.replace_input_of(u, LoopNode::EntryControl, outer_phi);
4400 }
4401 }
4402
4403 // create control and data nodes for out of loop uses (including region2)
4404 Node_List worklist;
4405 uint new_counter = C->unique();
4406 fix_ctrl_uses(wq, loop, old_new, ControlAroundStripMined, outer_head, nullptr, worklist);
4407
4408 Node_List *split_if_set = nullptr;
4409 Node_List *split_bool_set = nullptr;
4410 Node_List *split_cex_set = nullptr;
4411 fix_data_uses(wq, loop, ControlAroundStripMined, loop->skip_strip_mined(), new_counter, old_new, worklist,
4412 split_if_set, split_bool_set, split_cex_set);
4413
4414 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
4415
4416 if (exit_test != nullptr) {
4417 float cnt = exit_test->_fcnt;
4418 if (cnt != COUNT_UNKNOWN) {
4419 exit_test->_fcnt = cnt * f;
4420 old_new[exit_test->_idx]->as_If()->_fcnt = cnt * (1 - f);
4421 }
4422 }
4423
4424 C->set_major_progress();
4425
4426 return true;
4427 }
4428
4429 // AutoVectorize the loop: replace scalar ops with vector ops.
4430 PhaseIdealLoop::AutoVectorizeStatus
4431 PhaseIdealLoop::auto_vectorize(IdealLoopTree* lpt, VSharedData &vshared) {
4432 // Counted loop only
4433 if (!lpt->is_counted()) {
4434 return AutoVectorizeStatus::Impossible;
4435 }
4436
4437 // Main-loop only
4438 CountedLoopNode* cl = lpt->_head->as_CountedLoop();
4439 if (!cl->is_main_loop()) {
4440 return AutoVectorizeStatus::Impossible;
4441 }
4442
4443 VLoop vloop(lpt, false);
4444 if (!vloop.check_preconditions()) {
4445 return AutoVectorizeStatus::TriedAndFailed;
4446 }
4447
4448 // Ensure the shared data is cleared before each use
4449 vshared.clear();
4450
4451 const VLoopAnalyzer vloop_analyzer(vloop, vshared);
4452 if (!vloop_analyzer.success()) {
4453 return AutoVectorizeStatus::TriedAndFailed;
4454 }
4455
4456 SuperWord sw(vloop_analyzer);
4457 if (!sw.transform_loop()) {
4458 return AutoVectorizeStatus::TriedAndFailed;
4459 }
4460
4461 return AutoVectorizeStatus::Success;
4462 }
4463
4464 // Just before insert_pre_post_loops, we can multiversion the loop:
4465 //
4466 // multiversion_if
4467 // | |
4468 // fast_loop slow_loop
4469 //
4470 // In the fast_loop we can make speculative assumptions, and put the
4471 // conditions into the multiversion_if. If the conditions hold at runtime,
4472 // we enter the fast_loop, if the conditions fail, we take the slow_loop
4473 // instead which does not make any of the speculative assumptions.
4474 //
4475 // Note: we only multiversion the loop if the loop does not have any
4476 // auto vectorization check Predicate. If we have that predicate,
4477 // then we can simply add the speculative assumption checks to
4478 // that Predicate. This means we do not need to duplicate the
4479 // loop - we have a smaller graph and save compile time. Should
4480 // the conditions ever fail, then we deopt / trap at the Predicate
4481 // and recompile without that Predicate. At that point we will
4482 // multiversion the loop, so that we can still have speculative
4483 // runtime checks.
4484 //
4485 // We perform the multiversioning when the loop is still in its single
4486 // iteration form, even before we insert pre and post loops. This makes
4487 // the cloning much simpler. However, this means that both the fast
4488 // and the slow loop have to be optimized independently (adding pre
4489 // and post loops, unrolling the main loop, auto-vectorize etc.). And
4490 // we may end up not needing any speculative assumptions in the fast_loop
4491 // and then rejecting the slow_loop by constant folding the multiversion_if.
4492 //
4493 // Therefore, we "delay" the optimization of the slow_loop until we add
4494 // at least one speculative assumption for the fast_loop. If we never
4495 // add such a speculative runtime check, the OpaqueMultiversioningNode
4496 // of the multiversion_if constant folds to true after loop opts, and the
4497 // multiversion_if folds away the "delayed" slow_loop. If we add any
4498 // speculative assumption, then we notify the OpaqueMultiversioningNode
4499 // with "notify_slow_loop_that_it_can_resume_optimizations".
4500 //
4501 // Note: new runtime checks can be added to the multiversion_if with
4502 // PhaseIdealLoop::create_new_if_for_multiversion
4503 void PhaseIdealLoop::maybe_multiversion_for_auto_vectorization_runtime_checks(IdealLoopTree* lpt, Node_List& old_new) {
4504 CountedLoopNode* cl = lpt->_head->as_CountedLoop();
4505 LoopNode* outer_loop = cl->skip_strip_mined();
4506 Node* entry = outer_loop->in(LoopNode::EntryControl);
4507
4508 // Check we have multiversioning enabled, and are not already multiversioned.
4509 if (!LoopMultiversioning || cl->is_multiversion()) { return; }
4510
4511 // Check that we do not have a parse-predicate where we can add the runtime checks
4512 // during auto-vectorization.
4513 const Predicates predicates(entry);
4514 const PredicateBlock* predicate_block = predicates.auto_vectorization_check_block();
4515 if (predicate_block->has_parse_predicate()) { return; }
4516
4517 // Check node budget.
4518 uint estimate = lpt->est_loop_clone_sz(2);
4519 if (!may_require_nodes(estimate)) { return; }
4520
4521 do_multiversioning(lpt, old_new);
4522 }
4523
4524 // Returns true if the Reduction node is unordered.
4525 static bool is_unordered_reduction(Node* n) {
4526 return n->is_Reduction() && !n->as_Reduction()->requires_strict_order();
4527 }
4528
4529 // Having ReductionNodes in the loop is expensive. They need to recursively
4530 // fold together the vector values, for every vectorized loop iteration. If
4531 // we encounter the following pattern, we can vector accumulate the values
4532 // inside the loop, and only have a single UnorderedReduction after the loop.
4533 //
4534 // Note: UnorderedReduction represents a ReductionNode which does not require
4535 // calculating in strict order.
4536 //
4537 // CountedLoop init
4538 // | |
4539 // +------+ | +-----------------------+
4540 // | | | |
4541 // PhiNode (s) |
4542 // | |
4543 // | Vector |
4544 // | | |
4545 // UnorderedReduction (first_ur) |
4546 // | |
4547 // ... Vector |
4548 // | | |
4549 // UnorderedReduction (last_ur) |
4550 // | |
4551 // +---------------------+
4552 //
4553 // We patch the graph to look like this:
4554 //
4555 // CountedLoop identity_vector
4556 // | |
4557 // +-------+ | +---------------+
4558 // | | | |
4559 // PhiNode (v) |
4560 // | |
4561 // | Vector |
4562 // | | |
4563 // VectorAccumulator |
4564 // | |
4565 // ... Vector |
4566 // | | |
4567 // init VectorAccumulator |
4568 // | | | |
4569 // UnorderedReduction +-----------+
4570 //
4571 // We turned the scalar (s) Phi into a vectorized one (v). In the loop, we
4572 // use vector_accumulators, which do the same reductions, but only element
4573 // wise. This is a single operation per vector_accumulator, rather than many
4574 // for a UnorderedReduction. We can then reduce the last vector_accumulator
4575 // after the loop, and also reduce the init value into it.
4576 //
4577 // We can not do this with all reductions. Some reductions do not allow the
4578 // reordering of operations (for example float addition/multiplication require
4579 // strict order).
4580 void PhaseIdealLoop::move_unordered_reduction_out_of_loop(IdealLoopTree* loop) {
4581 assert(!C->major_progress() && loop->is_counted() && loop->is_innermost(), "sanity");
4582
4583 // Find all Phi nodes with an unordered Reduction on backedge.
4584 CountedLoopNode* cl = loop->_head->as_CountedLoop();
4585 for (DUIterator_Fast jmax, j = cl->fast_outs(jmax); j < jmax; j++) {
4586 Node* phi = cl->fast_out(j);
4587 // We have a phi with a single use, and an unordered Reduction on the backedge.
4588 if (!phi->is_Phi() || phi->outcnt() != 1 || !is_unordered_reduction(phi->in(2))) {
4589 continue;
4590 }
4591
4592 ReductionNode* last_ur = phi->in(2)->as_Reduction();
4593 assert(!last_ur->requires_strict_order(), "must be");
4594
4595 // Determine types
4596 const TypeVect* vec_t = last_ur->vect_type();
4597 uint vector_length = vec_t->length();
4598 BasicType bt = vec_t->element_basic_type();
4599
4600 // Convert opcode from vector-reduction -> scalar -> normal-vector-op
4601 const int sopc = VectorNode::scalar_opcode(last_ur->Opcode(), bt);
4602 const int vopc = VectorNode::opcode(sopc, bt);
4603 if (!Matcher::match_rule_supported_vector(vopc, vector_length, bt)) {
4604 DEBUG_ONLY( last_ur->dump(); )
4605 assert(false, "do not have normal vector op for this reduction");
4606 continue; // not implemented -> fails
4607 }
4608
4609 // Traverse up the chain of unordered Reductions, checking that it loops back to
4610 // the phi. Check that all unordered Reductions only have a single use, except for
4611 // the last (last_ur), which only has phi as a use in the loop, and all other uses
4612 // are outside the loop.
4613 ReductionNode* current = last_ur;
4614 ReductionNode* first_ur = nullptr;
4615 while (true) {
4616 assert(!current->requires_strict_order(), "sanity");
4617
4618 // Expect no ctrl and a vector_input from within the loop.
4619 Node* ctrl = current->in(0);
4620 Node* vector_input = current->in(2);
4621 if (ctrl != nullptr || get_ctrl(vector_input) != cl) {
4622 DEBUG_ONLY( current->dump(1); )
4623 assert(false, "reduction has ctrl or bad vector_input");
4624 break; // Chain traversal fails.
4625 }
4626
4627 assert(current->vect_type() != nullptr, "must have vector type");
4628 if (current->vect_type() != last_ur->vect_type()) {
4629 // Reductions do not have the same vector type (length and element type).
4630 break; // Chain traversal fails.
4631 }
4632
4633 // Expect single use of an unordered Reduction, except for last_ur.
4634 if (current == last_ur) {
4635 // Expect all uses to be outside the loop, except phi.
4636 for (DUIterator_Fast kmax, k = current->fast_outs(kmax); k < kmax; k++) {
4637 Node* use = current->fast_out(k);
4638 if (use != phi && ctrl_or_self(use) == cl) {
4639 DEBUG_ONLY( current->dump(-1); )
4640 assert(false, "reduction has use inside loop");
4641 // Should not be allowed by SuperWord::mark_reductions
4642 return; // bail out of optimization
4643 }
4644 }
4645 } else {
4646 if (current->outcnt() != 1) {
4647 break; // Chain traversal fails.
4648 }
4649 }
4650
4651 // Expect another unordered Reduction or phi as the scalar input.
4652 Node* scalar_input = current->in(1);
4653 if (is_unordered_reduction(scalar_input) &&
4654 scalar_input->Opcode() == current->Opcode()) {
4655 // Move up the unordered Reduction chain.
4656 current = scalar_input->as_Reduction();
4657 assert(!current->requires_strict_order(), "must be");
4658 } else if (scalar_input == phi) {
4659 // Chain terminates at phi.
4660 first_ur = current;
4661 current = nullptr;
4662 break; // Success.
4663 } else {
4664 // scalar_input is neither phi nor a matching reduction
4665 // Can for example be scalar reduction when we have
4666 // partial vectorization.
4667 break; // Chain traversal fails.
4668 }
4669 }
4670 if (current != nullptr) {
4671 // Chain traversal was not successful.
4672 continue;
4673 }
4674 assert(first_ur != nullptr, "must have successfully terminated chain traversal");
4675
4676 Node* identity_scalar = ReductionNode::make_identity_con_scalar(_igvn, sopc, bt);
4677 set_root_as_ctrl(identity_scalar);
4678 VectorNode* identity_vector = VectorNode::scalar2vector(identity_scalar, vector_length, bt);
4679 register_new_node(identity_vector, C->root());
4680 assert(vec_t == identity_vector->vect_type(), "matching vector type");
4681 VectorNode::trace_new_vector(identity_vector, "Unordered Reduction");
4682
4683 // Turn the scalar phi into a vector phi.
4684 _igvn.rehash_node_delayed(phi);
4685 Node* init = phi->in(1); // Remember init before replacing it.
4686 phi->set_req_X(1, identity_vector, &_igvn);
4687 phi->as_Type()->set_type(vec_t);
4688 _igvn.set_type(phi, vec_t);
4689
4690 // Traverse down the chain of unordered Reductions, and replace them with vector_accumulators.
4691 current = first_ur;
4692 while (true) {
4693 // Create vector_accumulator to replace current.
4694 Node* last_vector_accumulator = current->in(1);
4695 Node* vector_input = current->in(2);
4696 VectorNode* vector_accumulator = VectorNode::make(vopc, last_vector_accumulator, vector_input, vec_t);
4697 register_new_node(vector_accumulator, cl);
4698 _igvn.replace_node(current, vector_accumulator);
4699 VectorNode::trace_new_vector(vector_accumulator, "Unordered Reduction");
4700 if (current == last_ur) {
4701 break;
4702 }
4703 current = vector_accumulator->unique_out()->as_Reduction();
4704 assert(!current->requires_strict_order(), "must be");
4705 }
4706
4707 // Create post-loop reduction.
4708 Node* last_accumulator = phi->in(2);
4709 Node* post_loop_reduction = ReductionNode::make(sopc, nullptr, init, last_accumulator, bt);
4710
4711 // Take over uses of last_accumulator that are not in the loop.
4712 for (DUIterator i = last_accumulator->outs(); last_accumulator->has_out(i); i++) {
4713 Node* use = last_accumulator->out(i);
4714 if (use != phi && use != post_loop_reduction) {
4715 assert(ctrl_or_self(use) != cl, "use must be outside loop");
4716 use->replace_edge(last_accumulator, post_loop_reduction, &_igvn);
4717 --i;
4718 }
4719 }
4720 register_new_node(post_loop_reduction, get_late_ctrl(post_loop_reduction, cl));
4721 VectorNode::trace_new_vector(post_loop_reduction, "Unordered Reduction");
4722
4723 assert(last_accumulator->outcnt() == 2, "last_accumulator has 2 uses: phi and post_loop_reduction");
4724 assert(post_loop_reduction->outcnt() > 0, "should have taken over all non loop uses of last_accumulator");
4725 assert(phi->outcnt() == 1, "accumulator is the only use of phi");
4726 }
4727 }
4728
4729 void DataNodeGraph::clone_data_nodes(Node* new_ctrl) {
4730 for (uint i = 0; i < _data_nodes.size(); i++) {
4731 clone(_data_nodes[i], new_ctrl);
4732 }
4733 }
4734
4735 // Clone the given node and set it up properly. Set 'new_ctrl' as ctrl.
4736 void DataNodeGraph::clone(Node* node, Node* new_ctrl) {
4737 Node* clone = node->clone();
4738 _phase->igvn().register_new_node_with_optimizer(clone);
4739 _orig_to_new.put(node, clone);
4740 _phase->set_ctrl(clone, new_ctrl);
4741 if (node->is_CastII()) {
4742 clone->set_req(0, new_ctrl);
4743 }
4744 }
4745
4746 // Rewire the data inputs of all (unprocessed) cloned nodes, whose inputs are still pointing to the same inputs as their
4747 // corresponding orig nodes, to the newly cloned inputs to create a separate cloned graph.
4748 void DataNodeGraph::rewire_clones_to_cloned_inputs() {
4749 _orig_to_new.iterate_all([&](Node* node, Node* clone) {
4750 for (uint i = 1; i < node->req(); i++) {
4751 Node** cloned_input = _orig_to_new.get(node->in(i));
4752 if (cloned_input != nullptr) {
4753 // Input was also cloned -> rewire clone to the cloned input.
4754 _phase->igvn().replace_input_of(clone, i, *cloned_input);
4755 }
4756 }
4757 });
4758 }
4759
4760 // Clone all non-OpaqueLoop* nodes and apply the provided transformation strategy for OpaqueLoop* nodes.
4761 // Set 'new_ctrl' as ctrl for all cloned non-OpaqueLoop* nodes.
4762 void DataNodeGraph::clone_data_nodes_and_transform_opaque_loop_nodes(
4763 const TransformStrategyForOpaqueLoopNodes& transform_strategy,
4764 Node* new_ctrl) {
4765 for (uint i = 0; i < _data_nodes.size(); i++) {
4766 Node* data_node = _data_nodes[i];
4767 if (data_node->is_Opaque1()) {
4768 transform_opaque_node(transform_strategy, data_node);
4769 } else {
4770 clone(data_node, new_ctrl);
4771 }
4772 }
4773 }
4774
4775 void DataNodeGraph::transform_opaque_node(const TransformStrategyForOpaqueLoopNodes& transform_strategy, Node* node) {
4776 Node* transformed_node;
4777 if (node->is_OpaqueLoopInit()) {
4778 transformed_node = transform_strategy.transform_opaque_init(node->as_OpaqueLoopInit());
4779 } else {
4780 assert(node->is_OpaqueLoopStride(), "must be OpaqueLoopStrideNode");
4781 transformed_node = transform_strategy.transform_opaque_stride(node->as_OpaqueLoopStride());
4782 }
4783 // Add an orig->new mapping to correctly update the inputs of the copied graph in rewire_clones_to_cloned_inputs().
4784 _orig_to_new.put(node, transformed_node);
4785 }