1 /*
2 * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "opto/addnode.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/connode.hpp"
34 #include "opto/castnode.hpp"
35 #include "opto/divnode.hpp"
36 #include "opto/inlinetypenode.hpp"
37 #include "opto/loopnode.hpp"
38 #include "opto/matcher.hpp"
39 #include "opto/mulnode.hpp"
40 #include "opto/movenode.hpp"
41 #include "opto/opaquenode.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/subnode.hpp"
44 #include "opto/subtypenode.hpp"
45 #include "opto/vectornode.hpp"
46 #include "utilities/macros.hpp"
47
48 //=============================================================================
49 //------------------------------split_thru_phi---------------------------------
50 // Split Node 'n' through merge point if there is enough win.
51 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) {
52 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
53 // ConvI2L 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 // Inline types should not be split through Phis because they cannot be merged
67 // through Phi nodes but each value input needs to be merged individually.
68 if (n->is_InlineType()) {
69 return nullptr;
70 }
71
72 if (cannot_split_division(n, region)) {
73 return nullptr;
74 }
75
76 int wins = 0;
77 assert(!n->is_CFG(), "");
78 assert(region->is_Region(), "");
79
80 const Type* type = n->bottom_type();
81 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr();
82 Node* phi;
83 if (t_oop != nullptr && t_oop->is_known_instance_field()) {
84 int iid = t_oop->instance_id();
85 int index = C->get_alias_index(t_oop);
86 int offset = t_oop->offset();
87 phi = new PhiNode(region, type, nullptr, iid, index, offset);
88 } else {
89 phi = PhiNode::make_blank(region, n);
90 }
91 uint old_unique = C->unique();
92 for (uint i = 1; i < region->req(); i++) {
93 Node* x;
94 Node* the_clone = nullptr;
95 if (region->in(i) == C->top()) {
96 x = C->top(); // Dead path? Use a dead data op
97 } else {
98 x = n->clone(); // Else clone up the data op
99 the_clone = x; // Remember for possible deletion.
100 // Alter data node to use pre-phi inputs
101 if (n->in(0) == region)
102 x->set_req( 0, region->in(i) );
103 for (uint j = 1; j < n->req(); j++) {
104 Node* in = n->in(j);
105 if (in->is_Phi() && in->in(0) == region)
106 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
107 }
108 }
109 // Check for a 'win' on some paths
110 const Type* t = x->Value(&_igvn);
111
112 bool singleton = t->singleton();
113
114 // A TOP singleton indicates that there are no possible values incoming
115 // along a particular edge. In most cases, this is OK, and the Phi will
116 // be eliminated later in an Ideal call. However, we can't allow this to
117 // happen if the singleton occurs on loop entry, as the elimination of
118 // the PhiNode may cause the resulting node to migrate back to a previous
119 // loop iteration.
120 if (singleton && t == Type::TOP) {
121 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
122 // irreducible loop may not be indicated by an affirmative is_Loop());
123 // therefore, the only top we can split thru a phi is on a backedge of
124 // a loop.
125 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
126 }
127
128 if (singleton) {
129 wins++;
130 x = ((PhaseGVN&)_igvn).makecon(t);
131 } else {
132 // We now call Identity to try to simplify the cloned node.
133 // Note that some Identity methods call phase->type(this).
134 // Make sure that the type array is big enough for
135 // our new node, even though we may throw the node away.
136 // (Note: This tweaking with igvn only works because x is a new node.)
137 _igvn.set_type(x, t);
138 // If x is a TypeNode, capture any more-precise type permanently into Node
139 // otherwise it will be not updated during igvn->transform since
140 // igvn->type(x) is set to x->Value() already.
141 x->raise_bottom_type(t);
142 Node* y = x->Identity(&_igvn);
143 if (y != x) {
144 wins++;
145 x = y;
146 } else {
147 y = _igvn.hash_find(x);
148 if (y == nullptr) {
149 y = similar_subtype_check(x, region->in(i));
150 }
151 if (y) {
152 wins++;
153 x = y;
154 } else {
155 // Else x is a new node we are keeping
156 // We do not need register_new_node_with_optimizer
157 // because set_type has already been called.
158 _igvn._worklist.push(x);
159 }
160 }
161 }
162 if (x != the_clone && the_clone != nullptr)
163 _igvn.remove_dead_node(the_clone);
164 phi->set_req( i, x );
165 }
166 // Too few wins?
167 if (wins <= policy) {
168 _igvn.remove_dead_node(phi);
169 return nullptr;
170 }
171
172 // Record Phi
173 register_new_node( phi, region );
174
175 for (uint i2 = 1; i2 < phi->req(); i2++) {
176 Node *x = phi->in(i2);
177 // If we commoned up the cloned 'x' with another existing Node,
178 // the existing Node picks up a new use. We need to make the
179 // existing Node occur higher up so it dominates its uses.
180 Node *old_ctrl;
181 IdealLoopTree *old_loop;
182
183 if (x->is_Con()) {
184 // Constant's control is always root.
185 set_ctrl(x, C->root());
186 continue;
187 }
188 // The occasional new node
189 if (x->_idx >= old_unique) { // Found a new, unplaced node?
190 old_ctrl = nullptr;
191 old_loop = nullptr; // Not in any prior loop
192 } else {
193 old_ctrl = get_ctrl(x);
194 old_loop = get_loop(old_ctrl); // Get prior loop
195 }
196 // New late point must dominate new use
197 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
198 if (new_ctrl == old_ctrl) // Nothing is changed
199 continue;
200
201 IdealLoopTree *new_loop = get_loop(new_ctrl);
202
203 // Don't move x into a loop if its uses are
204 // outside of loop. Otherwise x will be cloned
205 // for each use outside of this loop.
206 IdealLoopTree *use_loop = get_loop(region);
207 if (!new_loop->is_member(use_loop) &&
208 (old_loop == nullptr || !new_loop->is_member(old_loop))) {
209 // Take early control, later control will be recalculated
210 // during next iteration of loop optimizations.
211 new_ctrl = get_early_ctrl(x);
212 new_loop = get_loop(new_ctrl);
213 }
214 // Set new location
215 set_ctrl(x, new_ctrl);
216 // If changing loop bodies, see if we need to collect into new body
217 if (old_loop != new_loop) {
218 if (old_loop && !old_loop->_child)
219 old_loop->_body.yank(x);
220 if (!new_loop->_child)
221 new_loop->_body.push(x); // Collect body info
222 }
223 }
224
225 return phi;
226 }
227
228 // Subtype checks that carry profile data don't common so look for a replacement by following edges
229 Node* PhaseIdealLoop::similar_subtype_check(const Node* x, Node* r_in) {
230 if (x->is_SubTypeCheck()) {
231 Node* in1 = x->in(1);
232 for (DUIterator_Fast imax, i = in1->fast_outs(imax); i < imax; i++) {
233 Node* u = in1->fast_out(i);
234 if (u != x && u->is_SubTypeCheck() && u->in(1) == x->in(1) && u->in(2) == x->in(2)) {
235 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) {
236 Node* bol = u->fast_out(j);
237 for (DUIterator_Fast kmax, k = bol->fast_outs(kmax); k < kmax; k++) {
238 Node* iff = bol->fast_out(k);
239 // Only dominating subtype checks are interesting: otherwise we risk replacing a subtype check by another with
240 // unrelated profile
241 if (iff->is_If() && is_dominator(iff, r_in)) {
242 return u;
243 }
244 }
245 }
246 }
247 }
248 }
249 return nullptr;
250 }
251
252 // Return true if 'n' is a Div or Mod node (without zero check If node which was removed earlier) with a loop phi divisor
253 // of a trip-counted (integer or long) loop with a backedge input that could be zero (include zero in its type range). In
254 // this case, we cannot split the division to the backedge as it could freely float above the loop exit check resulting in
255 // a division by zero. This situation is possible because the type of an increment node of an iv phi (trip-counter) could
256 // include zero while the iv phi does not (see PhiNode::Value() for trip-counted loops where we improve types of iv phis).
257 // We also need to check other loop phis as they could have been created in the same split-if pass when applying
258 // PhaseIdealLoop::split_thru_phi() to split nodes through an iv phi.
259 bool PhaseIdealLoop::cannot_split_division(const Node* n, const Node* region) const {
260 const Type* zero;
261 switch (n->Opcode()) {
262 case Op_DivI:
263 case Op_ModI:
264 zero = TypeInt::ZERO;
265 break;
266 case Op_DivL:
267 case Op_ModL:
268 zero = TypeLong::ZERO;
269 break;
270 default:
271 return false;
272 }
273
274 assert(n->in(0) == nullptr, "divisions with zero check should already have bailed out earlier in split-if");
275 Node* divisor = n->in(2);
276 return is_divisor_counted_loop_phi(divisor, region) &&
277 loop_phi_backedge_type_contains_zero(divisor, zero);
278 }
279
280 bool PhaseIdealLoop::is_divisor_counted_loop_phi(const Node* divisor, const Node* loop) {
281 return loop->is_BaseCountedLoop() && divisor->is_Phi() && divisor->in(0) == loop;
282 }
283
284 bool PhaseIdealLoop::loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const {
285 return _igvn.type(phi_divisor->in(LoopNode::LoopBackControl))->filter_speculative(zero) != Type::TOP;
286 }
287
288 //------------------------------dominated_by------------------------------------
289 // Replace the dominated test with an obvious true or false. Place it on the
290 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
291 // live path up to the dominating control.
292 void PhaseIdealLoop::dominated_by(IfProjNode* prevdom, IfNode* iff, bool flip, bool exclude_loop_predicate) {
293 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
294
295 // prevdom is the dominating projection of the dominating test.
296 assert(iff->Opcode() == Op_If ||
297 iff->Opcode() == Op_CountedLoopEnd ||
298 iff->Opcode() == Op_LongCountedLoopEnd ||
299 iff->Opcode() == Op_RangeCheck ||
300 iff->Opcode() == Op_ParsePredicate,
301 "Check this code when new subtype is added");
302
303 int pop = prevdom->Opcode();
304 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
305 if (flip) {
306 if (pop == Op_IfTrue)
307 pop = Op_IfFalse;
308 else
309 pop = Op_IfTrue;
310 }
311 // 'con' is set to true or false to kill the dominated test.
312 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
313 set_ctrl(con, C->root()); // Constant gets a new use
314 // Hack the dominated test
315 _igvn.replace_input_of(iff, 1, con);
316
317 // If I dont have a reachable TRUE and FALSE path following the IfNode then
318 // I can assume this path reaches an infinite loop. In this case it's not
319 // important to optimize the data Nodes - either the whole compilation will
320 // be tossed or this path (and all data Nodes) will go dead.
321 if (iff->outcnt() != 2) return;
322
323 // Make control-dependent data Nodes on the live path (path that will remain
324 // once the dominated IF is removed) become control-dependent on the
325 // dominating projection.
326 Node* dp = iff->proj_out_or_null(pop == Op_IfTrue);
327
328 // Loop predicates may have depending checks which should not
329 // be skipped. For example, range check predicate has two checks
330 // for lower and upper bounds.
331 if (dp == nullptr)
332 return;
333
334 ProjNode* dp_proj = dp->as_Proj();
335 ProjNode* unc_proj = iff->proj_out(1 - dp_proj->_con)->as_Proj();
336 if (exclude_loop_predicate &&
337 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != nullptr ||
338 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_profile_predicate) != nullptr ||
339 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != nullptr)) {
340 // If this is a range check (IfNode::is_range_check), do not
341 // reorder because Compile::allow_range_check_smearing might have
342 // changed the check.
343 return; // Let IGVN transformation change control dependence.
344 }
345
346 IdealLoopTree* old_loop = get_loop(dp);
347
348 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
349 Node* cd = dp->fast_out(i); // Control-dependent node
350 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check.
351 if (cd->depends_only_on_test() && _igvn.no_dependent_zero_check(cd)) {
352 assert(cd->in(0) == dp, "");
353 _igvn.replace_input_of(cd, 0, prevdom);
354 set_early_ctrl(cd, false);
355 IdealLoopTree* new_loop = get_loop(get_ctrl(cd));
356 if (old_loop != new_loop) {
357 if (!old_loop->_child) {
358 old_loop->_body.yank(cd);
359 }
360 if (!new_loop->_child) {
361 new_loop->_body.push(cd);
362 }
363 }
364 --i;
365 --imax;
366 }
367 }
368 }
369
370 //------------------------------has_local_phi_input----------------------------
371 // Return TRUE if 'n' has Phi inputs from its local block and no other
372 // block-local inputs (all non-local-phi inputs come from earlier blocks)
373 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
374 Node *n_ctrl = get_ctrl(n);
375 // See if some inputs come from a Phi in this block, or from before
376 // this block.
377 uint i;
378 for( i = 1; i < n->req(); i++ ) {
379 Node *phi = n->in(i);
380 if( phi->is_Phi() && phi->in(0) == n_ctrl )
381 break;
382 }
383 if( i >= n->req() )
384 return nullptr; // No Phi inputs; nowhere to clone thru
385
386 // Check for inputs created between 'n' and the Phi input. These
387 // must split as well; they have already been given the chance
388 // (courtesy of a post-order visit) and since they did not we must
389 // recover the 'cost' of splitting them by being very profitable
390 // when splitting 'n'. Since this is unlikely we simply give up.
391 for( i = 1; i < n->req(); i++ ) {
392 Node *m = n->in(i);
393 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
394 // We allow the special case of AddP's with no local inputs.
395 // This allows us to split-up address expressions.
396 if (m->is_AddP() &&
397 get_ctrl(m->in(AddPNode::Base)) != n_ctrl &&
398 get_ctrl(m->in(AddPNode::Address)) != n_ctrl &&
399 get_ctrl(m->in(AddPNode::Offset)) != n_ctrl) {
400 // Move the AddP up to the dominating point. That's fine because control of m's inputs
401 // must dominate get_ctrl(m) == n_ctrl and we just checked that the input controls are != n_ctrl.
402 Node* c = find_non_split_ctrl(idom(n_ctrl));
403 if (c->is_OuterStripMinedLoop()) {
404 c->as_Loop()->verify_strip_mined(1);
405 c = c->in(LoopNode::EntryControl);
406 }
407 set_ctrl_and_loop(m, c);
408 continue;
409 }
410 return nullptr;
411 }
412 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
413 }
414
415 return n_ctrl;
416 }
417
418 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
419 Node* PhaseIdealLoop::remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt) {
420 assert(bt == T_INT || bt == T_LONG, "only for integers");
421 int n_op = n->Opcode();
422
423 if (n_op == Op_LShift(bt)) {
424 // Scale is loop invariant
425 Node* scale = n->in(2);
426 Node* scale_ctrl = get_ctrl(scale);
427 IdealLoopTree* scale_loop = get_loop(scale_ctrl);
428 if (n_loop == scale_loop || !scale_loop->is_member(n_loop)) {
429 return nullptr;
430 }
431 const TypeInt* scale_t = scale->bottom_type()->isa_int();
432 if (scale_t != nullptr && scale_t->is_con() && scale_t->get_con() >= 16) {
433 return nullptr; // Dont bother with byte/short masking
434 }
435 // Add must vary with loop (else shift would be loop-invariant)
436 Node* add = n->in(1);
437 Node* add_ctrl = get_ctrl(add);
438 IdealLoopTree* add_loop = get_loop(add_ctrl);
439 if (n_loop != add_loop) {
440 return nullptr; // happens w/ evil ZKM loops
441 }
442
443 // Convert I-V into I+ (0-V); same for V-I
444 if (add->Opcode() == Op_Sub(bt) &&
445 _igvn.type(add->in(1)) != TypeInteger::zero(bt)) {
446 assert(add->Opcode() == Op_SubI || add->Opcode() == Op_SubL, "");
447 Node* zero = _igvn.integercon(0, bt);
448 set_ctrl(zero, C->root());
449 Node* neg = SubNode::make(zero, add->in(2), bt);
450 register_new_node(neg, get_ctrl(add->in(2)));
451 add = AddNode::make(add->in(1), neg, bt);
452 register_new_node(add, add_ctrl);
453 }
454 if (add->Opcode() != Op_Add(bt)) return nullptr;
455 assert(add->Opcode() == Op_AddI || add->Opcode() == Op_AddL, "");
456 // See if one add input is loop invariant
457 Node* add_var = add->in(1);
458 Node* add_var_ctrl = get_ctrl(add_var);
459 IdealLoopTree* add_var_loop = get_loop(add_var_ctrl);
460 Node* add_invar = add->in(2);
461 Node* add_invar_ctrl = get_ctrl(add_invar);
462 IdealLoopTree* add_invar_loop = get_loop(add_invar_ctrl);
463 if (add_invar_loop == n_loop) {
464 // Swap to find the invariant part
465 add_invar = add_var;
466 add_invar_ctrl = add_var_ctrl;
467 add_invar_loop = add_var_loop;
468 add_var = add->in(2);
469 } else if (add_var_loop != n_loop) { // Else neither input is loop invariant
470 return nullptr;
471 }
472 if (n_loop == add_invar_loop || !add_invar_loop->is_member(n_loop)) {
473 return nullptr; // No invariant part of the add?
474 }
475
476 // Yes! Reshape address expression!
477 Node* inv_scale = LShiftNode::make(add_invar, scale, bt);
478 Node* inv_scale_ctrl =
479 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
480 add_invar_ctrl : scale_ctrl;
481 register_new_node(inv_scale, inv_scale_ctrl);
482 Node* var_scale = LShiftNode::make(add_var, scale, bt);
483 register_new_node(var_scale, n_ctrl);
484 Node* var_add = AddNode::make(var_scale, inv_scale, bt);
485 register_new_node(var_add, n_ctrl);
486 _igvn.replace_node(n, var_add);
487 return var_add;
488 }
489 return nullptr;
490 }
491
492 //------------------------------remix_address_expressions----------------------
493 // Rework addressing expressions to get the most loop-invariant stuff
494 // moved out. We'd like to do all associative operators, but it's especially
495 // important (common) to do address expressions.
496 Node* PhaseIdealLoop::remix_address_expressions(Node* n) {
497 if (!has_ctrl(n)) return nullptr;
498 Node* n_ctrl = get_ctrl(n);
499 IdealLoopTree* n_loop = get_loop(n_ctrl);
500
501 // See if 'n' mixes loop-varying and loop-invariant inputs and
502 // itself is loop-varying.
503
504 // Only interested in binary ops (and AddP)
505 if (n->req() < 3 || n->req() > 4) return nullptr;
506
507 Node* n1_ctrl = get_ctrl(n->in( 1));
508 Node* n2_ctrl = get_ctrl(n->in( 2));
509 Node* n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
510 IdealLoopTree* n1_loop = get_loop(n1_ctrl);
511 IdealLoopTree* n2_loop = get_loop(n2_ctrl);
512 IdealLoopTree* n3_loop = get_loop(n3_ctrl);
513
514 // Does one of my inputs spin in a tighter loop than self?
515 if ((n_loop->is_member(n1_loop) && n_loop != n1_loop) ||
516 (n_loop->is_member(n2_loop) && n_loop != n2_loop) ||
517 (n_loop->is_member(n3_loop) && n_loop != n3_loop)) {
518 return nullptr; // Leave well enough alone
519 }
520
521 // Is at least one of my inputs loop-invariant?
522 if (n1_loop == n_loop &&
523 n2_loop == n_loop &&
524 n3_loop == n_loop) {
525 return nullptr; // No loop-invariant inputs
526 }
527
528 Node* res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_INT);
529 if (res != nullptr) {
530 return res;
531 }
532 res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_LONG);
533 if (res != nullptr) {
534 return res;
535 }
536
537 int n_op = n->Opcode();
538 // Replace (I+V) with (V+I)
539 if (n_op == Op_AddI ||
540 n_op == Op_AddL ||
541 n_op == Op_AddF ||
542 n_op == Op_AddD ||
543 n_op == Op_MulI ||
544 n_op == Op_MulL ||
545 n_op == Op_MulF ||
546 n_op == Op_MulD) {
547 if (n2_loop == n_loop) {
548 assert(n1_loop != n_loop, "");
549 n->swap_edges(1, 2);
550 }
551 }
552
553 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
554 // but not if I2 is a constant.
555 if (n_op == Op_AddP) {
556 if (n2_loop == n_loop && n3_loop != n_loop) {
557 if (n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con()) {
558 Node* n22_ctrl = get_ctrl(n->in(2)->in(2));
559 Node* n23_ctrl = get_ctrl(n->in(2)->in(3));
560 IdealLoopTree* n22loop = get_loop(n22_ctrl);
561 IdealLoopTree* n23_loop = get_loop(n23_ctrl);
562 if (n22loop != n_loop && n22loop->is_member(n_loop) &&
563 n23_loop == n_loop) {
564 Node* add1 = new AddPNode(n->in(1), n->in(2)->in(2), n->in(3));
565 // Stuff new AddP in the loop preheader
566 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
567 Node* add2 = new AddPNode(n->in(1), add1, n->in(2)->in(3));
568 register_new_node(add2, n_ctrl);
569 _igvn.replace_node(n, add2);
570 return add2;
571 }
572 }
573 }
574
575 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
576 if (n2_loop != n_loop && n3_loop == n_loop) {
577 if (n->in(3)->Opcode() == Op_AddX) {
578 Node* V = n->in(3)->in(1);
579 Node* I = n->in(3)->in(2);
580 if (is_member(n_loop,get_ctrl(V))) {
581 } else {
582 Node *tmp = V; V = I; I = tmp;
583 }
584 if (!is_member(n_loop,get_ctrl(I))) {
585 Node* add1 = new AddPNode(n->in(1), n->in(2), I);
586 // Stuff new AddP in the loop preheader
587 register_new_node(add1, n_loop->_head->as_Loop()->skip_strip_mined(1)->in(LoopNode::EntryControl));
588 Node* add2 = new AddPNode(n->in(1), add1, V);
589 register_new_node(add2, n_ctrl);
590 _igvn.replace_node(n, add2);
591 return add2;
592 }
593 }
594 }
595 }
596
597 return nullptr;
598 }
599
600 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1]))
601 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) {
602 assert(n->Opcode() == Op_AddI, "sanity");
603 Node * nn = nullptr;
604 Node * in1 = n->in(1);
605 Node * in2 = n->in(2);
606 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) {
607 IdealLoopTree* loop_n = get_loop(get_ctrl(n));
608 if (loop_n->is_counted() &&
609 loop_n->_head->as_Loop()->is_valid_counted_loop(T_INT) &&
610 Matcher::match_rule_supported(Op_MulAddVS2VI) &&
611 Matcher::match_rule_supported(Op_MulAddS2I)) {
612 Node* mul_in1 = in1->in(1);
613 Node* mul_in2 = in1->in(2);
614 Node* mul_in3 = in2->in(1);
615 Node* mul_in4 = in2->in(2);
616 if (mul_in1->Opcode() == Op_LoadS &&
617 mul_in2->Opcode() == Op_LoadS &&
618 mul_in3->Opcode() == Op_LoadS &&
619 mul_in4->Opcode() == Op_LoadS) {
620 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1));
621 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2));
622 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3));
623 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4));
624 IdealLoopTree* loop5 = get_loop(get_ctrl(in1));
625 IdealLoopTree* loop6 = get_loop(get_ctrl(in2));
626 // All nodes should be in the same counted loop.
627 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 &&
628 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) {
629 Node* adr1 = mul_in1->in(MemNode::Address);
630 Node* adr2 = mul_in2->in(MemNode::Address);
631 Node* adr3 = mul_in3->in(MemNode::Address);
632 Node* adr4 = mul_in4->in(MemNode::Address);
633 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) {
634 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) &&
635 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) {
636 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4);
637 register_new_node(nn, get_ctrl(n));
638 _igvn.replace_node(n, nn);
639 return nn;
640 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) &&
641 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) {
642 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3);
643 register_new_node(nn, get_ctrl(n));
644 _igvn.replace_node(n, nn);
645 return nn;
646 }
647 }
648 }
649 }
650 }
651 }
652 return nn;
653 }
654
655 //------------------------------conditional_move-------------------------------
656 // Attempt to replace a Phi with a conditional move. We have some pretty
657 // strict profitability requirements. All Phis at the merge point must
658 // be converted, so we can remove the control flow. We need to limit the
659 // number of c-moves to a small handful. All code that was in the side-arms
660 // of the CFG diamond is now speculatively executed. This code has to be
661 // "cheap enough". We are pretty much limited to CFG diamonds that merge
662 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
663 Node *PhaseIdealLoop::conditional_move( Node *region ) {
664
665 assert(region->is_Region(), "sanity check");
666 if (region->req() != 3) return nullptr;
667
668 // Check for CFG diamond
669 Node *lp = region->in(1);
670 Node *rp = region->in(2);
671 if (!lp || !rp) return nullptr;
672 Node *lp_c = lp->in(0);
673 if (lp_c == nullptr || lp_c != rp->in(0) || !lp_c->is_If()) return nullptr;
674 IfNode *iff = lp_c->as_If();
675
676 // Check for ops pinned in an arm of the diamond.
677 // Can't remove the control flow in this case
678 if (lp->outcnt() > 1) return nullptr;
679 if (rp->outcnt() > 1) return nullptr;
680
681 IdealLoopTree* r_loop = get_loop(region);
682 assert(r_loop == get_loop(iff), "sanity");
683 // Always convert to CMOVE if all results are used only outside this loop.
684 bool used_inside_loop = (r_loop == _ltree_root);
685
686 // Check profitability
687 int cost = 0;
688 int phis = 0;
689 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
690 Node *out = region->fast_out(i);
691 if (!out->is_Phi()) continue; // Ignore other control edges, etc
692 phis++;
693 PhiNode* phi = out->as_Phi();
694 BasicType bt = phi->type()->basic_type();
695 switch (bt) {
696 case T_DOUBLE:
697 case T_FLOAT:
698 if (C->use_cmove()) {
699 continue; //TODO: maybe we want to add some cost
700 }
701 cost += Matcher::float_cmove_cost(); // Could be very expensive
702 break;
703 case T_LONG: {
704 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
705 }
706 case T_INT: // These all CMOV fine
707 case T_ADDRESS: { // (RawPtr)
708 cost++;
709 break;
710 }
711 case T_NARROWOOP: // Fall through
712 case T_OBJECT: { // Base oops are OK, but not derived oops
713 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
714 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
715 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
716 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
717 // have a Phi for the base here that we convert to a CMOVE all is well
718 // and good. But if the base is dead, we'll not make a CMOVE. Later
719 // the allocator will have to produce a base by creating a CMOVE of the
720 // relevant bases. This puts the allocator in the business of
721 // manufacturing expensive instructions, generally a bad plan.
722 // Just Say No to Conditionally-Moved Derived Pointers.
723 if (tp && tp->offset() != 0)
724 return nullptr;
725 cost++;
726 break;
727 }
728 default:
729 return nullptr; // In particular, can't do memory or I/O
730 }
731 // Add in cost any speculative ops
732 for (uint j = 1; j < region->req(); j++) {
733 Node *proj = region->in(j);
734 Node *inp = phi->in(j);
735 if (inp->isa_InlineType()) {
736 // TODO 8302217 This prevents PhiNode::push_inline_types_through
737 return nullptr;
738 }
739 if (get_ctrl(inp) == proj) { // Found local op
740 cost++;
741 // Check for a chain of dependent ops; these will all become
742 // speculative in a CMOV.
743 for (uint k = 1; k < inp->req(); k++)
744 if (get_ctrl(inp->in(k)) == proj)
745 cost += ConditionalMoveLimit; // Too much speculative goo
746 }
747 }
748 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
749 // This will likely Split-If, a higher-payoff operation.
750 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
751 Node* use = phi->fast_out(k);
752 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
753 cost += ConditionalMoveLimit;
754 // Is there a use inside the loop?
755 // Note: check only basic types since CMoveP is pinned.
756 if (!used_inside_loop && is_java_primitive(bt)) {
757 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
758 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
759 used_inside_loop = true;
760 }
761 }
762 }
763 }//for
764 Node* bol = iff->in(1);
765 if (bol->Opcode() == Op_Opaque4) {
766 return nullptr; // Ignore loop predicate checks (the Opaque4 ensures they will go away)
767 }
768 assert(bol->Opcode() == Op_Bool, "Unexpected node");
769 int cmp_op = bol->in(1)->Opcode();
770 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode
771 return nullptr;
772 }
773 // It is expensive to generate flags from a float compare.
774 // Avoid duplicated float compare.
775 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return nullptr;
776
777 float infrequent_prob = PROB_UNLIKELY_MAG(3);
778 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
779 if (used_inside_loop) {
780 if (cost >= ConditionalMoveLimit) return nullptr; // Too much goo
781
782 // BlockLayoutByFrequency optimization moves infrequent branch
783 // from hot path. No point in CMOV'ing in such case (110 is used
784 // instead of 100 to take into account not exactness of float value).
785 if (BlockLayoutByFrequency) {
786 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
787 }
788 }
789 // Check for highly predictable branch. No point in CMOV'ing if
790 // we are going to predict accurately all the time.
791 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
792 //keep going
793 } else if (iff->_prob < infrequent_prob ||
794 iff->_prob > (1.0f - infrequent_prob))
795 return nullptr;
796
797 // --------------
798 // Now replace all Phis with CMOV's
799 Node *cmov_ctrl = iff->in(0);
800 uint flip = (lp->Opcode() == Op_IfTrue);
801 Node_List wq;
802 while (1) {
803 PhiNode* phi = nullptr;
804 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
805 Node *out = region->fast_out(i);
806 if (out->is_Phi()) {
807 phi = out->as_Phi();
808 break;
809 }
810 }
811 if (phi == nullptr || _igvn.type(phi) == Type::TOP) {
812 break;
813 }
814 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
815 // Move speculative ops
816 wq.push(phi);
817 while (wq.size() > 0) {
818 Node *n = wq.pop();
819 for (uint j = 1; j < n->req(); j++) {
820 Node* m = n->in(j);
821 if (m != nullptr && !is_dominator(get_ctrl(m), cmov_ctrl)) {
822 #ifndef PRODUCT
823 if (PrintOpto && VerifyLoopOptimizations) {
824 tty->print(" speculate: ");
825 m->dump();
826 }
827 #endif
828 set_ctrl(m, cmov_ctrl);
829 wq.push(m);
830 }
831 }
832 }
833 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
834 register_new_node( cmov, cmov_ctrl );
835 _igvn.replace_node( phi, cmov );
836 #ifndef PRODUCT
837 if (TraceLoopOpts) {
838 tty->print("CMOV ");
839 r_loop->dump_head();
840 if (Verbose) {
841 bol->in(1)->dump(1);
842 cmov->dump(1);
843 }
844 }
845 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
846 #endif
847 }
848
849 // The useless CFG diamond will fold up later; see the optimization in
850 // RegionNode::Ideal.
851 _igvn._worklist.push(region);
852
853 return iff->in(1);
854 }
855
856 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
857 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
858 Node* u = m->fast_out(i);
859 if (u->is_CFG()) {
860 if (u->is_NeverBranch()) {
861 u = u->as_NeverBranch()->proj_out(0);
862 enqueue_cfg_uses(u, wq);
863 } else {
864 wq.push(u);
865 }
866 }
867 }
868 }
869
870 // Try moving a store out of a loop, right before the loop
871 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
872 // Store has to be first in the loop body
873 IdealLoopTree *n_loop = get_loop(n_ctrl);
874 if (n->is_Store() && n_loop != _ltree_root &&
875 n_loop->is_loop() && n_loop->_head->is_Loop() &&
876 n->in(0) != nullptr) {
877 Node* address = n->in(MemNode::Address);
878 Node* value = n->in(MemNode::ValueIn);
879 Node* mem = n->in(MemNode::Memory);
880 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
881 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
882
883 // - address and value must be loop invariant
884 // - memory must be a memory Phi for the loop
885 // - Store must be the only store on this memory slice in the
886 // loop: if there's another store following this one then value
887 // written at iteration i by the second store could be overwritten
888 // at iteration i+n by the first store: it's not safe to move the
889 // first store out of the loop
890 // - nothing must observe the memory Phi: it guarantees no read
891 // before the store, we are also guaranteed the store post
892 // dominates the loop head (ignoring a possible early
893 // exit). Otherwise there would be extra Phi involved between the
894 // loop's Phi and the store.
895 // - there must be no early exit from the loop before the Store
896 // (such an exit most of the time would be an extra use of the
897 // memory Phi but sometimes is a bottom memory Phi that takes the
898 // store as input).
899
900 if (!n_loop->is_member(address_loop) &&
901 !n_loop->is_member(value_loop) &&
902 mem->is_Phi() && mem->in(0) == n_loop->_head &&
903 mem->outcnt() == 1 &&
904 mem->in(LoopNode::LoopBackControl) == n) {
905
906 assert(n_loop->_tail != nullptr, "need a tail");
907 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
908
909 // Verify that there's no early exit of the loop before the store.
910 bool ctrl_ok = false;
911 {
912 // Follow control from loop head until n, we exit the loop or
913 // we reach the tail
914 ResourceMark rm;
915 Unique_Node_List wq;
916 wq.push(n_loop->_head);
917
918 for (uint next = 0; next < wq.size(); ++next) {
919 Node *m = wq.at(next);
920 if (m == n->in(0)) {
921 ctrl_ok = true;
922 continue;
923 }
924 assert(!has_ctrl(m), "should be CFG");
925 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
926 ctrl_ok = false;
927 break;
928 }
929 enqueue_cfg_uses(m, wq);
930 if (wq.size() > 10) {
931 ctrl_ok = false;
932 break;
933 }
934 }
935 }
936 if (ctrl_ok) {
937 // move the Store
938 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
939 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
940 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
941 // Disconnect the phi now. An empty phi can confuse other
942 // optimizations in this pass of loop opts.
943 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
944 n_loop->_body.yank(mem);
945
946 set_ctrl_and_loop(n, n->in(0));
947
948 return n;
949 }
950 }
951 }
952 return nullptr;
953 }
954
955 // Try moving a store out of a loop, right after the loop
956 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
957 if (n->is_Store() && n->in(0) != nullptr) {
958 Node *n_ctrl = get_ctrl(n);
959 IdealLoopTree *n_loop = get_loop(n_ctrl);
960 // Store must be in a loop
961 if (n_loop != _ltree_root && !n_loop->_irreducible) {
962 Node* address = n->in(MemNode::Address);
963 Node* value = n->in(MemNode::ValueIn);
964 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
965 // address must be loop invariant
966 if (!n_loop->is_member(address_loop)) {
967 // Store must be last on this memory slice in the loop and
968 // nothing in the loop must observe it
969 Node* phi = nullptr;
970 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
971 Node* u = n->fast_out(i);
972 if (has_ctrl(u)) { // control use?
973 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
974 if (!n_loop->is_member(u_loop)) {
975 continue;
976 }
977 if (u->is_Phi() && u->in(0) == n_loop->_head) {
978 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
979 // multiple phis on the same slice are possible
980 if (phi != nullptr) {
981 return;
982 }
983 phi = u;
984 continue;
985 }
986 }
987 return;
988 }
989 if (phi != nullptr) {
990 // Nothing in the loop before the store (next iteration)
991 // must observe the stored value
992 bool mem_ok = true;
993 {
994 ResourceMark rm;
995 Unique_Node_List wq;
996 wq.push(phi);
997 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
998 Node *m = wq.at(next);
999 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
1000 Node* u = m->fast_out(i);
1001 if (u->is_Store() || u->is_Phi()) {
1002 if (u != n) {
1003 wq.push(u);
1004 mem_ok = (wq.size() <= 10);
1005 }
1006 } else {
1007 mem_ok = false;
1008 break;
1009 }
1010 }
1011 }
1012 }
1013 if (mem_ok) {
1014 // Move the store out of the loop if the LCA of all
1015 // users (except for the phi) is outside the loop.
1016 Node* hook = new Node(1);
1017 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead
1018 _igvn.rehash_node_delayed(phi);
1019 int count = phi->replace_edge(n, hook, &_igvn);
1020 assert(count > 0, "inconsistent phi");
1021
1022 // Compute latest point this store can go
1023 Node* lca = get_late_ctrl(n, get_ctrl(n));
1024 if (lca->is_OuterStripMinedLoop()) {
1025 lca = lca->in(LoopNode::EntryControl);
1026 }
1027 if (n_loop->is_member(get_loop(lca))) {
1028 // LCA is in the loop - bail out
1029 _igvn.replace_node(hook, n);
1030 return;
1031 }
1032 #ifdef ASSERT
1033 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
1034 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
1035 n_loop->_head->as_Loop()->verify_strip_mined(1);
1036 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
1037 IdealLoopTree* outer_loop = get_loop(outer);
1038 assert(n_loop->_parent == outer_loop, "broken loop tree");
1039 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
1040 }
1041 #endif
1042 lca = place_outside_loop(lca, n_loop);
1043 assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop");
1044 assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch(), "must not be moved into inner loop");
1045
1046 // Move store out of the loop
1047 _igvn.replace_node(hook, n->in(MemNode::Memory));
1048 _igvn.replace_input_of(n, 0, lca);
1049 set_ctrl_and_loop(n, lca);
1050
1051 // Disconnect the phi now. An empty phi can confuse other
1052 // optimizations in this pass of loop opts..
1053 if (phi->in(LoopNode::LoopBackControl) == phi) {
1054 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
1055 n_loop->_body.yank(phi);
1056 }
1057 }
1058 }
1059 }
1060 }
1061 }
1062 }
1063
1064 // If UseArrayMarkWordCheck is enabled, we can't use immutable memory for the flat array check
1065 // because we are loading the mark word which is mutable. Although the bits we are interested in
1066 // are immutable (we check for markWord::unlocked_value), we need to use raw memory to not break
1067 // anti dependency analysis. Below code will attempt to still move flat array checks out of loops,
1068 // mainly to enable loop unswitching.
1069 void PhaseIdealLoop::move_flat_array_check_out_of_loop(Node* n) {
1070 // Skip checks for more than one array
1071 if (n->req() > 3) {
1072 return;
1073 }
1074 Node* mem = n->in(FlatArrayCheckNode::Memory);
1075 Node* array = n->in(FlatArrayCheckNode::ArrayOrKlass)->uncast();
1076 IdealLoopTree* check_loop = get_loop(get_ctrl(n));
1077 IdealLoopTree* ary_loop = get_loop(get_ctrl(array));
1078
1079 // Check if array is loop invariant
1080 if (!check_loop->is_member(ary_loop)) {
1081 // Walk up memory graph from the check until we leave the loop
1082 VectorSet wq;
1083 wq.set(mem->_idx);
1084 while (check_loop->is_member(get_loop(ctrl_or_self(mem)))) {
1085 if (mem->is_Phi()) {
1086 mem = mem->in(1);
1087 } else if (mem->is_MergeMem()) {
1088 mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1089 } else if (mem->is_Proj()) {
1090 mem = mem->in(0);
1091 } else if (mem->is_MemBar() || mem->is_SafePoint()) {
1092 mem = mem->in(TypeFunc::Memory);
1093 } else if (mem->is_Store() || mem->is_LoadStore() || mem->is_ClearArray()) {
1094 mem = mem->in(MemNode::Memory);
1095 } else {
1096 #ifdef ASSERT
1097 mem->dump();
1098 #endif
1099 ShouldNotReachHere();
1100 }
1101 if (wq.test_set(mem->_idx)) {
1102 return;
1103 }
1104 }
1105 // Replace memory input and re-compute ctrl to move the check out of the loop
1106 _igvn.replace_input_of(n, 1, mem);
1107 set_ctrl_and_loop(n, get_early_ctrl(n));
1108 Node* bol = n->unique_out();
1109 set_ctrl_and_loop(bol, get_early_ctrl(bol));
1110 }
1111 }
1112
1113 //------------------------------split_if_with_blocks_pre-----------------------
1114 // Do the real work in a non-recursive function. Data nodes want to be
1115 // cloned in the pre-order so they can feed each other nicely.
1116 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
1117 // Cloning these guys is unlikely to win
1118 int n_op = n->Opcode();
1119 if (n_op == Op_MergeMem) {
1120 return n;
1121 }
1122 if (n->is_Proj()) {
1123 return n;
1124 }
1125
1126 if (UseArrayMarkWordCheck && n->isa_FlatArrayCheck()) {
1127 move_flat_array_check_out_of_loop(n);
1128 return n;
1129 }
1130
1131 // Do not clone-up CmpFXXX variations, as these are always
1132 // followed by a CmpI
1133 if (n->is_Cmp()) {
1134 return n;
1135 }
1136 // Attempt to use a conditional move instead of a phi/branch
1137 if (ConditionalMoveLimit > 0 && n_op == Op_Region) {
1138 Node *cmov = conditional_move( n );
1139 if (cmov) {
1140 return cmov;
1141 }
1142 }
1143 if (n->is_CFG() || n->is_LoadStore()) {
1144 return n;
1145 }
1146 if (n->is_Opaque1()) { // Opaque nodes cannot be mod'd
1147 if (!C->major_progress()) { // If chance of no more loop opts...
1148 _igvn._worklist.push(n); // maybe we'll remove them
1149 }
1150 return n;
1151 }
1152
1153 if (n->is_Con()) {
1154 return n; // No cloning for Con nodes
1155 }
1156
1157 Node *n_ctrl = get_ctrl(n);
1158 if (!n_ctrl) {
1159 return n; // Dead node
1160 }
1161
1162 Node* res = try_move_store_before_loop(n, n_ctrl);
1163 if (res != nullptr) {
1164 return n;
1165 }
1166
1167 // Attempt to remix address expressions for loop invariants
1168 Node *m = remix_address_expressions( n );
1169 if( m ) return m;
1170
1171 if (n_op == Op_AddI) {
1172 Node *nn = convert_add_to_muladd( n );
1173 if ( nn ) return nn;
1174 }
1175
1176 if (n->is_ConstraintCast()) {
1177 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
1178 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
1179 // Node control inputs don't necessarily agree with loop control info (due to
1180 // transformations happened in between), thus additional dominance check is needed
1181 // to keep loop info valid.
1182 if (dom_cast != nullptr && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
1183 _igvn.replace_node(n, dom_cast);
1184 return dom_cast;
1185 }
1186 }
1187
1188 // Determine if the Node has inputs from some local Phi.
1189 // Returns the block to clone thru.
1190 Node *n_blk = has_local_phi_input( n );
1191 if( !n_blk ) return n;
1192
1193 // Do not clone the trip counter through on a CountedLoop
1194 // (messes up the canonical shape).
1195 if (((n_blk->is_CountedLoop() || (n_blk->is_Loop() && n_blk->as_Loop()->is_loop_nest_inner_loop())) && n->Opcode() == Op_AddI) ||
1196 (n_blk->is_LongCountedLoop() && n->Opcode() == Op_AddL)) {
1197 return n;
1198 }
1199 // Pushing a shift through the iv Phi can get in the way of addressing optimizations or range check elimination
1200 if (n_blk->is_BaseCountedLoop() && n->Opcode() == Op_LShift(n_blk->as_BaseCountedLoop()->bt()) &&
1201 n->in(1) == n_blk->as_BaseCountedLoop()->phi()) {
1202 return n;
1203 }
1204
1205 // Check for having no control input; not pinned. Allow
1206 // dominating control.
1207 if (n->in(0)) {
1208 Node *dom = idom(n_blk);
1209 if (dom_lca(n->in(0), dom) != n->in(0)) {
1210 return n;
1211 }
1212 }
1213 // Policy: when is it profitable. You must get more wins than
1214 // policy before it is considered profitable. Policy is usually 0,
1215 // so 1 win is considered profitable. Big merges will require big
1216 // cloning, so get a larger policy.
1217 int policy = n_blk->req() >> 2;
1218
1219 // If the loop is a candidate for range check elimination,
1220 // delay splitting through it's phi until a later loop optimization
1221 if (n_blk->is_BaseCountedLoop()) {
1222 IdealLoopTree *lp = get_loop(n_blk);
1223 if (lp && lp->_rce_candidate) {
1224 return n;
1225 }
1226 }
1227
1228 if (must_throttle_split_if()) return n;
1229
1230 // Split 'n' through the merge point if it is profitable
1231 Node *phi = split_thru_phi( n, n_blk, policy );
1232 if (!phi) return n;
1233
1234 // Found a Phi to split thru!
1235 // Replace 'n' with the new phi
1236 _igvn.replace_node( n, phi );
1237 // Moved a load around the loop, 'en-registering' something.
1238 if (n_blk->is_Loop() && n->is_Load() &&
1239 !phi->in(LoopNode::LoopBackControl)->is_Load())
1240 C->set_major_progress();
1241
1242 return phi;
1243 }
1244
1245 static bool merge_point_too_heavy(Compile* C, Node* region) {
1246 // Bail out if the region and its phis have too many users.
1247 int weight = 0;
1248 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1249 weight += region->fast_out(i)->outcnt();
1250 }
1251 int nodes_left = C->max_node_limit() - C->live_nodes();
1252 if (weight * 8 > nodes_left) {
1253 if (PrintOpto) {
1254 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
1255 }
1256 return true;
1257 } else {
1258 return false;
1259 }
1260 }
1261
1262 static bool merge_point_safe(Node* region) {
1263 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1264 // having a PhiNode input. This sidesteps the dangerous case where the split
1265 // ConvI2LNode may become TOP if the input Value() does not
1266 // overlap the ConvI2L range, leaving a node which may not dominate its
1267 // uses.
1268 // A better fix for this problem can be found in the BugTraq entry, but
1269 // expediency for Mantis demands this hack.
1270 #ifdef _LP64
1271 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1272 Node* n = region->fast_out(i);
1273 if (n->is_Phi()) {
1274 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1275 Node* m = n->fast_out(j);
1276 if (m->Opcode() == Op_ConvI2L)
1277 return false;
1278 if (m->is_CastII()) {
1279 return false;
1280 }
1281 }
1282 }
1283 }
1284 #endif
1285 return true;
1286 }
1287
1288
1289 //------------------------------place_outside_loop---------------------------------
1290 // Place some computation outside of this loop on the path to the use passed as argument
1291 Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) const {
1292 Node* head = loop->_head;
1293 assert(!loop->is_member(get_loop(useblock)), "must be outside loop");
1294 if (head->is_Loop() && head->as_Loop()->is_strip_mined()) {
1295 loop = loop->_parent;
1296 assert(loop->_head->is_OuterStripMinedLoop(), "malformed strip mined loop");
1297 }
1298
1299 // Pick control right outside the loop
1300 for (;;) {
1301 Node* dom = idom(useblock);
1302 if (loop->is_member(get_loop(dom)) ||
1303 // NeverBranch nodes are not assigned to the loop when constructed
1304 (dom->is_NeverBranch() && loop->is_member(get_loop(dom->in(0))))) {
1305 break;
1306 }
1307 useblock = dom;
1308 }
1309 assert(find_non_split_ctrl(useblock) == useblock, "should be non split control");
1310 return useblock;
1311 }
1312
1313
1314 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1315 if (!n->is_If() || n->is_BaseCountedLoopEnd()) {
1316 return false;
1317 }
1318 if (!n->in(0)->is_Region()) {
1319 return false;
1320 }
1321
1322 Node* region = n->in(0);
1323 Node* dom = idom(region);
1324 if (!dom->is_If() || !n->as_If()->same_condition(dom, &_igvn)) {
1325 return false;
1326 }
1327 IfNode* dom_if = dom->as_If();
1328 Node* proj_true = dom_if->proj_out(1);
1329 Node* proj_false = dom_if->proj_out(0);
1330
1331 for (uint i = 1; i < region->req(); i++) {
1332 if (is_dominator(proj_true, region->in(i))) {
1333 continue;
1334 }
1335 if (is_dominator(proj_false, region->in(i))) {
1336 continue;
1337 }
1338 return false;
1339 }
1340
1341 return true;
1342 }
1343
1344
1345 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) {
1346 if (must_throttle_split_if()) {
1347 return false;
1348 }
1349
1350 // Do not do 'split-if' if irreducible loops are present.
1351 if (_has_irreducible_loops) {
1352 return false;
1353 }
1354
1355 if (merge_point_too_heavy(C, n_ctrl)) {
1356 return false;
1357 }
1358
1359 // Do not do 'split-if' if some paths are dead. First do dead code
1360 // elimination and then see if its still profitable.
1361 for (uint i = 1; i < n_ctrl->req(); i++) {
1362 if (n_ctrl->in(i) == C->top()) {
1363 return false;
1364 }
1365 }
1366
1367 // If trying to do a 'Split-If' at the loop head, it is only
1368 // profitable if the cmp folds up on BOTH paths. Otherwise we
1369 // risk peeling a loop forever.
1370
1371 // CNC - Disabled for now. Requires careful handling of loop
1372 // body selection for the cloned code. Also, make sure we check
1373 // for any input path not being in the same loop as n_ctrl. For
1374 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1375 // because the alternative loop entry points won't be converted
1376 // into LoopNodes.
1377 IdealLoopTree *n_loop = get_loop(n_ctrl);
1378 for (uint j = 1; j < n_ctrl->req(); j++) {
1379 if (get_loop(n_ctrl->in(j)) != n_loop) {
1380 return false;
1381 }
1382 }
1383
1384 // Check for safety of the merge point.
1385 if (!merge_point_safe(n_ctrl)) {
1386 return false;
1387 }
1388
1389 return true;
1390 }
1391
1392 // Detect if the node is the inner strip-mined loop
1393 // Return: null if it's not the case, or the exit of outer strip-mined loop
1394 static Node* is_inner_of_stripmined_loop(const Node* out) {
1395 Node* out_le = nullptr;
1396
1397 if (out->is_CountedLoopEnd()) {
1398 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode();
1399
1400 if (loop != nullptr && loop->is_strip_mined()) {
1401 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit();
1402 }
1403 }
1404
1405 return out_le;
1406 }
1407
1408 bool PhaseIdealLoop::flat_array_element_type_check(Node *n) {
1409 // If the CmpP is a subtype check for a value that has just been
1410 // loaded from an array, the subtype check guarantees the value
1411 // can't be stored in a flat array and the load of the value
1412 // happens with a flat array check then: push the type check
1413 // through the phi of the flat array check. This needs special
1414 // logic because the subtype check's input is not a phi but a
1415 // LoadKlass that must first be cloned through the phi.
1416 if (n->Opcode() != Op_CmpP) {
1417 return false;
1418 }
1419
1420 Node* klassptr = n->in(1);
1421 Node* klasscon = n->in(2);
1422
1423 if (klassptr->is_DecodeNarrowPtr()) {
1424 klassptr = klassptr->in(1);
1425 }
1426
1427 if (klassptr->Opcode() != Op_LoadKlass && klassptr->Opcode() != Op_LoadNKlass) {
1428 return false;
1429 }
1430
1431 if (!klasscon->is_Con()) {
1432 return false;
1433 }
1434
1435 Node* addr = klassptr->in(MemNode::Address);
1436
1437 if (!addr->is_AddP()) {
1438 return false;
1439 }
1440
1441 intptr_t offset;
1442 Node* obj = AddPNode::Ideal_base_and_offset(addr, &_igvn, offset);
1443
1444 if (obj == nullptr) {
1445 return false;
1446 }
1447
1448 assert(obj != nullptr && addr->in(AddPNode::Base) == addr->in(AddPNode::Address), "malformed AddP?");
1449 if (obj->Opcode() == Op_CastPP) {
1450 obj = obj->in(1);
1451 }
1452
1453 if (!obj->is_Phi()) {
1454 return false;
1455 }
1456
1457 Node* region = obj->in(0);
1458
1459 Node* phi = PhiNode::make_blank(region, n->in(1));
1460 for (uint i = 1; i < region->req(); i++) {
1461 Node* in = obj->in(i);
1462 Node* ctrl = region->in(i);
1463 if (addr->in(AddPNode::Base) != obj) {
1464 Node* cast = addr->in(AddPNode::Base);
1465 assert(cast->Opcode() == Op_CastPP && cast->in(0) != nullptr, "inconsistent subgraph");
1466 Node* cast_clone = cast->clone();
1467 cast_clone->set_req(0, ctrl);
1468 cast_clone->set_req(1, in);
1469 register_new_node(cast_clone, ctrl);
1470 const Type* tcast = cast_clone->Value(&_igvn);
1471 _igvn.set_type(cast_clone, tcast);
1472 cast_clone->as_Type()->set_type(tcast);
1473 in = cast_clone;
1474 }
1475 Node* addr_clone = addr->clone();
1476 addr_clone->set_req(AddPNode::Base, in);
1477 addr_clone->set_req(AddPNode::Address, in);
1478 register_new_node(addr_clone, ctrl);
1479 _igvn.set_type(addr_clone, addr_clone->Value(&_igvn));
1480 Node* klassptr_clone = klassptr->clone();
1481 klassptr_clone->set_req(2, addr_clone);
1482 register_new_node(klassptr_clone, ctrl);
1483 _igvn.set_type(klassptr_clone, klassptr_clone->Value(&_igvn));
1484 if (klassptr != n->in(1)) {
1485 Node* decode = n->in(1);
1486 assert(decode->is_DecodeNarrowPtr(), "inconsistent subgraph");
1487 Node* decode_clone = decode->clone();
1488 decode_clone->set_req(1, klassptr_clone);
1489 register_new_node(decode_clone, ctrl);
1490 _igvn.set_type(decode_clone, decode_clone->Value(&_igvn));
1491 klassptr_clone = decode_clone;
1492 }
1493 phi->set_req(i, klassptr_clone);
1494 }
1495 register_new_node(phi, region);
1496 Node* orig = n->in(1);
1497 _igvn.replace_input_of(n, 1, phi);
1498 split_if_with_blocks_post(n);
1499 if (n->outcnt() != 0) {
1500 _igvn.replace_input_of(n, 1, orig);
1501 _igvn.remove_dead_node(phi);
1502 }
1503 return true;
1504 }
1505
1506 //------------------------------split_if_with_blocks_post----------------------
1507 // Do the real work in a non-recursive function. CFG hackery wants to be
1508 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1509 // info.
1510 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1511
1512 if (flat_array_element_type_check(n)) {
1513 return;
1514 }
1515
1516 // Cloning Cmp through Phi's involves the split-if transform.
1517 // FastLock is not used by an If
1518 if (n->is_Cmp() && !n->is_FastLock()) {
1519 Node *n_ctrl = get_ctrl(n);
1520 // Determine if the Node has inputs from some local Phi.
1521 // Returns the block to clone thru.
1522 Node *n_blk = has_local_phi_input(n);
1523 if (n_blk != n_ctrl) {
1524 return;
1525 }
1526
1527 if (!can_split_if(n_ctrl)) {
1528 return;
1529 }
1530
1531 if (n->outcnt() != 1) {
1532 return; // Multiple bool's from 1 compare?
1533 }
1534 Node *bol = n->unique_out();
1535 assert(bol->is_Bool(), "expect a bool here");
1536 if (bol->outcnt() != 1) {
1537 return;// Multiple branches from 1 compare?
1538 }
1539 Node *iff = bol->unique_out();
1540
1541 // Check some safety conditions
1542 if (iff->is_If()) { // Classic split-if?
1543 if (iff->in(0) != n_ctrl) {
1544 return; // Compare must be in same blk as if
1545 }
1546 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1547 // Can't split CMove with different control.
1548 if (get_ctrl(iff) != n_ctrl) {
1549 return;
1550 }
1551 if (get_ctrl(iff->in(2)) == n_ctrl ||
1552 get_ctrl(iff->in(3)) == n_ctrl) {
1553 return; // Inputs not yet split-up
1554 }
1555 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1556 return; // Loop-invar test gates loop-varying CMOVE
1557 }
1558 } else {
1559 return; // some other kind of node, such as an Allocate
1560 }
1561
1562 // When is split-if profitable? Every 'win' on means some control flow
1563 // goes dead, so it's almost always a win.
1564 int policy = 0;
1565 // Split compare 'n' through the merge point if it is profitable
1566 Node *phi = split_thru_phi( n, n_ctrl, policy);
1567 if (!phi) {
1568 return;
1569 }
1570
1571 // Found a Phi to split thru!
1572 // Replace 'n' with the new phi
1573 _igvn.replace_node(n, phi);
1574
1575 // Now split the bool up thru the phi
1576 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1577 guarantee(bolphi != nullptr, "null boolean phi node");
1578
1579 _igvn.replace_node(bol, bolphi);
1580 assert(iff->in(1) == bolphi, "");
1581
1582 if (bolphi->Value(&_igvn)->singleton()) {
1583 return;
1584 }
1585
1586 // Conditional-move? Must split up now
1587 if (!iff->is_If()) {
1588 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1589 _igvn.replace_node(iff, cmovphi);
1590 return;
1591 }
1592
1593 // Now split the IF
1594 do_split_if(iff);
1595 return;
1596 }
1597
1598 // Two identical ifs back to back can be merged
1599 if (try_merge_identical_ifs(n)) {
1600 return;
1601 }
1602
1603 // Check for an IF ready to split; one that has its
1604 // condition codes input coming from a Phi at the block start.
1605 int n_op = n->Opcode();
1606
1607 // Check for an IF being dominated by another IF same test
1608 if (n_op == Op_If ||
1609 n_op == Op_RangeCheck) {
1610 Node *bol = n->in(1);
1611 uint max = bol->outcnt();
1612 // Check for same test used more than once?
1613 if (bol->is_Bool() && (max > 1 || bol->in(1)->is_SubTypeCheck())) {
1614 // Search up IDOMs to see if this IF is dominated.
1615 Node* cmp = bol->in(1);
1616 Node *cutoff = cmp->is_SubTypeCheck() ? dom_lca(get_ctrl(cmp->in(1)), get_ctrl(cmp->in(2))) : get_ctrl(bol);
1617
1618 // Now search up IDOMs till cutoff, looking for a dominating test
1619 Node *prevdom = n;
1620 Node *dom = idom(prevdom);
1621 while (dom != cutoff) {
1622 if (dom->req() > 1 && n->as_If()->same_condition(dom, &_igvn) && prevdom->in(0) == dom &&
1623 safe_for_if_replacement(dom)) {
1624 // It's invalid to move control dependent data nodes in the inner
1625 // strip-mined loop, because:
1626 // 1) break validation of LoopNode::verify_strip_mined()
1627 // 2) move code with side-effect in strip-mined loop
1628 // Move to the exit of outer strip-mined loop in that case.
1629 Node* out_le = is_inner_of_stripmined_loop(dom);
1630 if (out_le != nullptr) {
1631 prevdom = out_le;
1632 }
1633 // Replace the dominated test with an obvious true or false.
1634 // Place it on the IGVN worklist for later cleanup.
1635 C->set_major_progress();
1636 dominated_by(prevdom->as_IfProj(), n->as_If(), false, true);
1637 DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } );
1638 return;
1639 }
1640 prevdom = dom;
1641 dom = idom(prevdom);
1642 }
1643 }
1644 }
1645
1646 try_sink_out_of_loop(n);
1647
1648 try_move_store_after_loop(n);
1649
1650 // Remove multiple allocations of the same inline type
1651 if (n->is_InlineType()) {
1652 n->as_InlineType()->remove_redundant_allocations(this);
1653 }
1654 }
1655
1656 // Transform:
1657 //
1658 // if (some_condition) {
1659 // // body 1
1660 // } else {
1661 // // body 2
1662 // }
1663 // if (some_condition) {
1664 // // body 3
1665 // } else {
1666 // // body 4
1667 // }
1668 //
1669 // into:
1670 //
1671 //
1672 // if (some_condition) {
1673 // // body 1
1674 // // body 3
1675 // } else {
1676 // // body 2
1677 // // body 4
1678 // }
1679 bool PhaseIdealLoop::try_merge_identical_ifs(Node* n) {
1680 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1681 Node *n_ctrl = n->in(0);
1682 IfNode* dom_if = idom(n_ctrl)->as_If();
1683 if (n->in(1) != dom_if->in(1)) {
1684 assert(n->in(1)->in(1)->is_SubTypeCheck() &&
1685 (n->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr ||
1686 dom_if->in(1)->in(1)->as_SubTypeCheck()->method() != nullptr), "only for subtype checks with profile data attached");
1687 _igvn.replace_input_of(n, 1, dom_if->in(1));
1688 }
1689 ProjNode* dom_proj_true = dom_if->proj_out(1);
1690 ProjNode* dom_proj_false = dom_if->proj_out(0);
1691
1692 // Now split the IF
1693 RegionNode* new_false_region;
1694 RegionNode* new_true_region;
1695 do_split_if(n, &new_false_region, &new_true_region);
1696 assert(new_false_region->req() == new_true_region->req(), "");
1697 #ifdef ASSERT
1698 for (uint i = 1; i < new_false_region->req(); ++i) {
1699 assert(new_false_region->in(i)->in(0) == new_true_region->in(i)->in(0), "unexpected shape following split if");
1700 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");
1701 }
1702 #endif
1703 assert(new_false_region->in(1)->in(0)->in(1) == dom_if->in(1), "dominating if and dominated if after split must share test");
1704
1705 // We now have:
1706 // if (some_condition) {
1707 // // body 1
1708 // if (some_condition) {
1709 // body3: // new_true_region
1710 // // body3
1711 // } else {
1712 // goto body4;
1713 // }
1714 // } else {
1715 // // body 2
1716 // if (some_condition) {
1717 // goto body3;
1718 // } else {
1719 // body4: // new_false_region
1720 // // body4;
1721 // }
1722 // }
1723 //
1724
1725 // clone pinned nodes thru the resulting regions
1726 push_pinned_nodes_thru_region(dom_if, new_true_region);
1727 push_pinned_nodes_thru_region(dom_if, new_false_region);
1728
1729 // Optimize out the cloned ifs. Because pinned nodes were cloned, this also allows a CastPP that would be dependent
1730 // 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
1731 // unrelated control dependency.
1732 for (uint i = 1; i < new_false_region->req(); i++) {
1733 if (is_dominator(dom_proj_true, new_false_region->in(i))) {
1734 dominated_by(dom_proj_true->as_IfProj(), new_false_region->in(i)->in(0)->as_If(), false, false);
1735 } else {
1736 assert(is_dominator(dom_proj_false, new_false_region->in(i)), "bad if");
1737 dominated_by(dom_proj_false->as_IfProj(), new_false_region->in(i)->in(0)->as_If(), false, false);
1738 }
1739 }
1740 return true;
1741 }
1742 return false;
1743 }
1744
1745 void PhaseIdealLoop::push_pinned_nodes_thru_region(IfNode* dom_if, Node* region) {
1746 for (DUIterator i = region->outs(); region->has_out(i); i++) {
1747 Node* u = region->out(i);
1748 if (!has_ctrl(u) || u->is_Phi() || !u->depends_only_on_test() || !_igvn.no_dependent_zero_check(u)) {
1749 continue;
1750 }
1751 assert(u->in(0) == region, "not a control dependent node?");
1752 uint j = 1;
1753 for (; j < u->req(); ++j) {
1754 Node* in = u->in(j);
1755 if (!is_dominator(ctrl_or_self(in), dom_if)) {
1756 break;
1757 }
1758 }
1759 if (j == u->req()) {
1760 Node *phi = PhiNode::make_blank(region, u);
1761 for (uint k = 1; k < region->req(); ++k) {
1762 Node* clone = u->clone();
1763 clone->set_req(0, region->in(k));
1764 register_new_node(clone, region->in(k));
1765 phi->init_req(k, clone);
1766 }
1767 register_new_node(phi, region);
1768 _igvn.replace_node(u, phi);
1769 --i;
1770 }
1771 }
1772 }
1773
1774 bool PhaseIdealLoop::safe_for_if_replacement(const Node* dom) const {
1775 if (!dom->is_CountedLoopEnd()) {
1776 return true;
1777 }
1778 CountedLoopEndNode* le = dom->as_CountedLoopEnd();
1779 CountedLoopNode* cl = le->loopnode();
1780 if (cl == nullptr) {
1781 return true;
1782 }
1783 if (!cl->is_main_loop()) {
1784 return true;
1785 }
1786 if (cl->is_canonical_loop_entry() == nullptr) {
1787 return true;
1788 }
1789 // Further unrolling is possible so loop exit condition might change
1790 return false;
1791 }
1792
1793 // See if a shared loop-varying computation has no loop-varying uses.
1794 // Happens if something is only used for JVM state in uncommon trap exits,
1795 // like various versions of induction variable+offset. Clone the
1796 // computation per usage to allow it to sink out of the loop.
1797 void PhaseIdealLoop::try_sink_out_of_loop(Node* n) {
1798 if (has_ctrl(n) &&
1799 !n->is_Phi() &&
1800 !n->is_Bool() &&
1801 !n->is_Proj() &&
1802 !n->is_MergeMem() &&
1803 !n->is_CMove() &&
1804 n->Opcode() != Op_Opaque4 &&
1805 !n->is_Type()) {
1806 Node *n_ctrl = get_ctrl(n);
1807 IdealLoopTree *n_loop = get_loop(n_ctrl);
1808
1809 if (n->in(0) != nullptr) {
1810 IdealLoopTree* loop_ctrl = get_loop(n->in(0));
1811 if (n_loop != loop_ctrl && n_loop->is_member(loop_ctrl)) {
1812 // n has a control input inside a loop but get_ctrl() is member of an outer loop. This could happen, for example,
1813 // for Div nodes inside a loop (control input inside loop) without a use except for an UCT (outside the loop).
1814 // Rewire control of n to right outside of the loop, regardless if its input(s) are later sunk or not.
1815 _igvn.replace_input_of(n, 0, place_outside_loop(n_ctrl, loop_ctrl));
1816 }
1817 }
1818 if (n_loop != _ltree_root && n->outcnt() > 1) {
1819 // Compute early control: needed for anti-dependence analysis. It's also possible that as a result of
1820 // previous transformations in this loop opts round, the node can be hoisted now: early control will tell us.
1821 Node* early_ctrl = compute_early_ctrl(n, n_ctrl);
1822 if (n_loop->is_member(get_loop(early_ctrl)) && // check that this one can't be hoisted now
1823 ctrl_of_all_uses_out_of_loop(n, early_ctrl, n_loop)) { // All uses in outer loops!
1824 assert(!n->is_Store() && !n->is_LoadStore(), "no node with a side effect");
1825 Node* outer_loop_clone = nullptr;
1826 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin;) {
1827 Node* u = n->last_out(j); // Clone private computation per use
1828 _igvn.rehash_node_delayed(u);
1829 Node* x = n->clone(); // Clone computation
1830 Node* x_ctrl = nullptr;
1831 if (u->is_Phi()) {
1832 // Replace all uses of normal nodes. Replace Phi uses
1833 // individually, so the separate Nodes can sink down
1834 // different paths.
1835 uint k = 1;
1836 while (u->in(k) != n) k++;
1837 u->set_req(k, x);
1838 // x goes next to Phi input path
1839 x_ctrl = u->in(0)->in(k);
1840 // Find control for 'x' next to use but not inside inner loops.
1841 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1842 --j;
1843 } else { // Normal use
1844 if (has_ctrl(u)) {
1845 x_ctrl = get_ctrl(u);
1846 } else {
1847 x_ctrl = u->in(0);
1848 }
1849 // Find control for 'x' next to use but not inside inner loops.
1850 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1851 // Replace all uses
1852 if (u->is_ConstraintCast() && _igvn.type(n)->higher_equal(u->bottom_type()) && u->in(0) == x_ctrl) {
1853 // If we're sinking a chain of data nodes, we might have inserted a cast to pin the use which is not necessary
1854 // anymore now that we're going to pin n as well
1855 _igvn.replace_node(u, x);
1856 --j;
1857 } else {
1858 int nb = u->replace_edge(n, x, &_igvn);
1859 j -= nb;
1860 }
1861 }
1862
1863 if (n->is_Load()) {
1864 // For loads, add a control edge to a CFG node outside of the loop
1865 // to force them to not combine and return back inside the loop
1866 // during GVN optimization (4641526).
1867 assert(x_ctrl == get_late_ctrl_with_anti_dep(x->as_Load(), early_ctrl, x_ctrl), "anti-dependences were already checked");
1868
1869 IdealLoopTree* x_loop = get_loop(x_ctrl);
1870 Node* x_head = x_loop->_head;
1871 if (x_head->is_Loop() && x_head->is_OuterStripMinedLoop()) {
1872 // Do not add duplicate LoadNodes to the outer strip mined loop
1873 if (outer_loop_clone != nullptr) {
1874 _igvn.replace_node(x, outer_loop_clone);
1875 continue;
1876 }
1877 outer_loop_clone = x;
1878 }
1879 x->set_req(0, x_ctrl);
1880 } else if (n->in(0) != nullptr){
1881 x->set_req(0, x_ctrl);
1882 }
1883 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1884 assert(!n_loop->is_member(get_loop(x_ctrl)), "should have moved out of loop");
1885 register_new_node(x, x_ctrl);
1886
1887 // Chain of AddP nodes: (AddP base (AddP base (AddP base )))
1888 // All AddP nodes must keep the same base after sinking so:
1889 // 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,
1890 // their bases remain the same.
1891 // (see 2- below)
1892 assert(!x->is_AddP() || !x->in(AddPNode::Address)->is_AddP() ||
1893 x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base) ||
1894 !x->in(AddPNode::Address)->in(AddPNode::Base)->eqv_uncast(x->in(AddPNode::Base)), "unexpected AddP shape");
1895 if (x->in(0) == nullptr && !x->is_DecodeNarrowPtr() &&
1896 !(x->is_AddP() && x->in(AddPNode::Address)->is_AddP() && x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base))) {
1897 assert(!x->is_Load(), "load should be pinned");
1898 // Use a cast node to pin clone out of loop
1899 Node* cast = nullptr;
1900 for (uint k = 0; k < x->req(); k++) {
1901 Node* in = x->in(k);
1902 if (in != nullptr && n_loop->is_member(get_loop(get_ctrl(in)))) {
1903 const Type* in_t = _igvn.type(in);
1904 cast = ConstraintCastNode::make_cast_for_type(x_ctrl, in, in_t, ConstraintCastNode::UnconditionalDependency);
1905 }
1906 if (cast != nullptr) {
1907 Node* prev = _igvn.hash_find_insert(cast);
1908 if (prev != nullptr && get_ctrl(prev) == x_ctrl) {
1909 cast->destruct(&_igvn);
1910 cast = prev;
1911 } else {
1912 register_new_node(cast, x_ctrl);
1913 }
1914 x->replace_edge(in, cast);
1915 // Chain of AddP nodes:
1916 // 2- A CastPP of the base is only added now that all AddP nodes are sunk
1917 if (x->is_AddP() && k == AddPNode::Base) {
1918 update_addp_chain_base(x, n->in(AddPNode::Base), cast);
1919 }
1920 break;
1921 }
1922 }
1923 assert(cast != nullptr, "must have added a cast to pin the node");
1924 }
1925 }
1926 _igvn.remove_dead_node(n);
1927 }
1928 _dom_lca_tags_round = 0;
1929 }
1930 }
1931 }
1932
1933 void PhaseIdealLoop::update_addp_chain_base(Node* x, Node* old_base, Node* new_base) {
1934 ResourceMark rm;
1935 Node_List wq;
1936 wq.push(x);
1937 while (wq.size() != 0) {
1938 Node* n = wq.pop();
1939 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1940 Node* u = n->fast_out(i);
1941 if (u->is_AddP() && u->in(AddPNode::Base) == old_base) {
1942 _igvn.replace_input_of(u, AddPNode::Base, new_base);
1943 wq.push(u);
1944 }
1945 }
1946 }
1947 }
1948
1949 // Compute the early control of a node by following its inputs until we reach
1950 // nodes that are pinned. Then compute the LCA of the control of all pinned nodes.
1951 Node* PhaseIdealLoop::compute_early_ctrl(Node* n, Node* n_ctrl) {
1952 Node* early_ctrl = nullptr;
1953 ResourceMark rm;
1954 Unique_Node_List wq;
1955 wq.push(n);
1956 for (uint i = 0; i < wq.size(); i++) {
1957 Node* m = wq.at(i);
1958 Node* c = nullptr;
1959 if (m->is_CFG()) {
1960 c = m;
1961 } else if (m->pinned()) {
1962 c = m->in(0);
1963 } else {
1964 for (uint j = 0; j < m->req(); j++) {
1965 Node* in = m->in(j);
1966 if (in != nullptr) {
1967 wq.push(in);
1968 }
1969 }
1970 }
1971 if (c != nullptr) {
1972 assert(is_dominator(c, n_ctrl), "control input must dominate current control");
1973 if (early_ctrl == nullptr || is_dominator(early_ctrl, c)) {
1974 early_ctrl = c;
1975 }
1976 }
1977 }
1978 assert(is_dominator(early_ctrl, n_ctrl), "early control must dominate current control");
1979 return early_ctrl;
1980 }
1981
1982 bool PhaseIdealLoop::ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop) {
1983 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1984 Node* u = n->fast_out(i);
1985 if (u->is_Opaque1()) {
1986 return false; // Found loop limit, bugfix for 4677003
1987 }
1988 // We can't reuse tags in PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal() so make sure calls to
1989 // get_late_ctrl_with_anti_dep() use their own tag
1990 _dom_lca_tags_round++;
1991 assert(_dom_lca_tags_round != 0, "shouldn't wrap around");
1992
1993 if (u->is_Phi()) {
1994 for (uint j = 1; j < u->req(); ++j) {
1995 if (u->in(j) == n && !ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, u->in(0)->in(j))) {
1996 return false;
1997 }
1998 }
1999 } else {
2000 Node* ctrl = has_ctrl(u) ? get_ctrl(u) : u->in(0);
2001 if (!ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, ctrl)) {
2002 return false;
2003 }
2004 }
2005 }
2006 return true;
2007 }
2008
2009 bool PhaseIdealLoop::ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl) {
2010 if (n->is_Load()) {
2011 ctrl = get_late_ctrl_with_anti_dep(n->as_Load(), n_ctrl, ctrl);
2012 }
2013 IdealLoopTree *u_loop = get_loop(ctrl);
2014 if (u_loop == n_loop) {
2015 return false; // Found loop-varying use
2016 }
2017 if (n_loop->is_member(u_loop)) {
2018 return false; // Found use in inner loop
2019 }
2020 // 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
2021 // to a check that's eliminated by range check elimination, it becomes input to an expression that feeds into the exit
2022 // test of the pre loop above the point in the graph where it's pinned.
2023 if (n_loop->_head->is_CountedLoop() && n_loop->_head->as_CountedLoop()->is_pre_loop() &&
2024 u_loop->_head->is_CountedLoop() && u_loop->_head->as_CountedLoop()->is_main_loop() &&
2025 n_loop->_next == get_loop(u_loop->_head->as_CountedLoop()->skip_strip_mined())) {
2026 return false;
2027 }
2028 return true;
2029 }
2030
2031 //------------------------------split_if_with_blocks---------------------------
2032 // Check for aggressive application of 'split-if' optimization,
2033 // using basic block level info.
2034 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) {
2035 Node* root = C->root();
2036 visited.set(root->_idx); // first, mark root as visited
2037 // Do pre-visit work for root
2038 Node* n = split_if_with_blocks_pre(root);
2039 uint cnt = n->outcnt();
2040 uint i = 0;
2041
2042 while (true) {
2043 // Visit all children
2044 if (i < cnt) {
2045 Node* use = n->raw_out(i);
2046 ++i;
2047 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
2048 // Now do pre-visit work for this use
2049 use = split_if_with_blocks_pre(use);
2050 nstack.push(n, i); // Save parent and next use's index.
2051 n = use; // Process all children of current use.
2052 cnt = use->outcnt();
2053 i = 0;
2054 }
2055 }
2056 else {
2057 // All of n's children have been processed, complete post-processing.
2058 if (cnt != 0 && !n->is_Con()) {
2059 assert(has_node(n), "no dead nodes");
2060 split_if_with_blocks_post(n);
2061 }
2062 if (must_throttle_split_if()) {
2063 nstack.clear();
2064 }
2065 if (nstack.is_empty()) {
2066 // Finished all nodes on stack.
2067 break;
2068 }
2069 // Get saved parent node and next use's index. Visit the rest of uses.
2070 n = nstack.node();
2071 cnt = n->outcnt();
2072 i = nstack.index();
2073 nstack.pop();
2074 }
2075 }
2076 }
2077
2078
2079 //=============================================================================
2080 //
2081 // C L O N E A L O O P B O D Y
2082 //
2083
2084 //------------------------------clone_iff--------------------------------------
2085 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2086 // "Nearly" because all Nodes have been cloned from the original in the loop,
2087 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2088 // through the Phi recursively, and return a Bool.
2089 Node* PhaseIdealLoop::clone_iff(PhiNode* phi) {
2090
2091 // Convert this Phi into a Phi merging Bools
2092 uint i;
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_iff(b->as_Phi()));
2097 } else {
2098 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
2099 }
2100 }
2101
2102 Node* n = phi->in(1);
2103 Node* sample_opaque = nullptr;
2104 Node *sample_bool = nullptr;
2105 if (n->Opcode() == Op_Opaque4) {
2106 sample_opaque = n;
2107 sample_bool = n->in(1);
2108 assert(sample_bool->is_Bool(), "wrong type");
2109 } else {
2110 sample_bool = n;
2111 }
2112 Node* sample_cmp = sample_bool->in(1);
2113 const Type* t = Type::TOP;
2114 const TypePtr* at = nullptr;
2115 if (sample_cmp->is_FlatArrayCheck()) {
2116 // Left input of a FlatArrayCheckNode is memory, set the (adr) type of the phi accordingly
2117 assert(sample_cmp->in(1)->bottom_type() == Type::MEMORY, "unexpected input type");
2118 t = Type::MEMORY;
2119 at = TypeRawPtr::BOTTOM;
2120 }
2121
2122 // Make Phis to merge the Cmp's inputs.
2123 PhiNode *phi1 = new PhiNode(phi->in(0), t, at);
2124 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
2125 for (i = 1; i < phi->req(); i++) {
2126 Node *n1 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
2127 Node *n2 = sample_opaque == nullptr ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
2128 phi1->set_req(i, n1);
2129 phi2->set_req(i, n2);
2130 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2131 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2132 }
2133 // See if these Phis have been made before.
2134 // Register with optimizer
2135 Node *hit1 = _igvn.hash_find_insert(phi1);
2136 if (hit1) { // Hit, toss just made Phi
2137 _igvn.remove_dead_node(phi1); // Remove new phi
2138 assert(hit1->is_Phi(), "" );
2139 phi1 = (PhiNode*)hit1; // Use existing phi
2140 } else { // Miss
2141 _igvn.register_new_node_with_optimizer(phi1);
2142 }
2143 Node *hit2 = _igvn.hash_find_insert(phi2);
2144 if (hit2) { // Hit, toss just made Phi
2145 _igvn.remove_dead_node(phi2); // Remove new phi
2146 assert(hit2->is_Phi(), "" );
2147 phi2 = (PhiNode*)hit2; // Use existing phi
2148 } else { // Miss
2149 _igvn.register_new_node_with_optimizer(phi2);
2150 }
2151 // Register Phis with loop/block info
2152 set_ctrl(phi1, phi->in(0));
2153 set_ctrl(phi2, phi->in(0));
2154 // Make a new Cmp
2155 Node *cmp = sample_cmp->clone();
2156 cmp->set_req(1, phi1);
2157 cmp->set_req(2, phi2);
2158 _igvn.register_new_node_with_optimizer(cmp);
2159 set_ctrl(cmp, phi->in(0));
2160
2161 // Make a new Bool
2162 Node *b = sample_bool->clone();
2163 b->set_req(1,cmp);
2164 _igvn.register_new_node_with_optimizer(b);
2165 set_ctrl(b, phi->in(0));
2166
2167 if (sample_opaque != nullptr) {
2168 Node* opaque = sample_opaque->clone();
2169 opaque->set_req(1, b);
2170 _igvn.register_new_node_with_optimizer(opaque);
2171 set_ctrl(opaque, phi->in(0));
2172 return opaque;
2173 }
2174
2175 assert(b->is_Bool(), "");
2176 return b;
2177 }
2178
2179 //------------------------------clone_bool-------------------------------------
2180 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
2181 // "Nearly" because all Nodes have been cloned from the original in the loop,
2182 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
2183 // through the Phi recursively, and return a Bool.
2184 CmpNode*PhaseIdealLoop::clone_bool(PhiNode* phi) {
2185 uint i;
2186 // Convert this Phi into a Phi merging Bools
2187 for( i = 1; i < phi->req(); i++ ) {
2188 Node *b = phi->in(i);
2189 if( b->is_Phi() ) {
2190 _igvn.replace_input_of(phi, i, clone_bool(b->as_Phi()));
2191 } else {
2192 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
2193 }
2194 }
2195
2196 Node *sample_cmp = phi->in(1);
2197
2198 // Make Phis to merge the Cmp's inputs.
2199 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
2200 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
2201 for( uint j = 1; j < phi->req(); j++ ) {
2202 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
2203 Node *n1, *n2;
2204 if( cmp_top->is_Cmp() ) {
2205 n1 = cmp_top->in(1);
2206 n2 = cmp_top->in(2);
2207 } else {
2208 n1 = n2 = cmp_top;
2209 }
2210 phi1->set_req( j, n1 );
2211 phi2->set_req( j, n2 );
2212 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
2213 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
2214 }
2215
2216 // See if these Phis have been made before.
2217 // Register with optimizer
2218 Node *hit1 = _igvn.hash_find_insert(phi1);
2219 if( hit1 ) { // Hit, toss just made Phi
2220 _igvn.remove_dead_node(phi1); // Remove new phi
2221 assert( hit1->is_Phi(), "" );
2222 phi1 = (PhiNode*)hit1; // Use existing phi
2223 } else { // Miss
2224 _igvn.register_new_node_with_optimizer(phi1);
2225 }
2226 Node *hit2 = _igvn.hash_find_insert(phi2);
2227 if( hit2 ) { // Hit, toss just made Phi
2228 _igvn.remove_dead_node(phi2); // Remove new phi
2229 assert( hit2->is_Phi(), "" );
2230 phi2 = (PhiNode*)hit2; // Use existing phi
2231 } else { // Miss
2232 _igvn.register_new_node_with_optimizer(phi2);
2233 }
2234 // Register Phis with loop/block info
2235 set_ctrl(phi1, phi->in(0));
2236 set_ctrl(phi2, phi->in(0));
2237 // Make a new Cmp
2238 Node *cmp = sample_cmp->clone();
2239 cmp->set_req( 1, phi1 );
2240 cmp->set_req( 2, phi2 );
2241 _igvn.register_new_node_with_optimizer(cmp);
2242 set_ctrl(cmp, phi->in(0));
2243
2244 assert( cmp->is_Cmp(), "" );
2245 return (CmpNode*)cmp;
2246 }
2247
2248 //------------------------------sink_use---------------------------------------
2249 // If 'use' was in the loop-exit block, it now needs to be sunk
2250 // below the post-loop merge point.
2251 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
2252 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
2253 set_ctrl(use, post_loop);
2254 for (DUIterator j = use->outs(); use->has_out(j); j++)
2255 sink_use(use->out(j), post_loop);
2256 }
2257 }
2258
2259 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
2260 IdealLoopTree* loop, IdealLoopTree* outer_loop,
2261 Node_List*& split_if_set, Node_List*& split_bool_set,
2262 Node_List*& split_cex_set, Node_List& worklist,
2263 uint new_counter, CloneLoopMode mode) {
2264 Node* nnn = old_new[old->_idx];
2265 // Copy uses to a worklist, so I can munge the def-use info
2266 // with impunity.
2267 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2268 worklist.push(old->fast_out(j));
2269
2270 while( worklist.size() ) {
2271 Node *use = worklist.pop();
2272 if (!has_node(use)) continue; // Ignore dead nodes
2273 if (use->in(0) == C->top()) continue;
2274 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2275 // Check for data-use outside of loop - at least one of OLD or USE
2276 // must not be a CFG node.
2277 #ifdef ASSERT
2278 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == nullptr) {
2279 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
2280 assert(mode != IgnoreStripMined, "incorrect cloning mode");
2281 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node");
2282 }
2283 #endif
2284 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
2285
2286 // If the Data use is an IF, that means we have an IF outside of the
2287 // loop that is switching on a condition that is set inside of the
2288 // loop. Happens if people set a loop-exit flag; then test the flag
2289 // in the loop to break the loop, then test is again outside of the
2290 // loop to determine which way the loop exited.
2291 // Loop predicate If node connects to Bool node through Opaque1 node.
2292 //
2293 // If the use is an AllocateArray through its ValidLengthTest input,
2294 // make sure the Bool/Cmp input is cloned down to avoid a Phi between
2295 // the AllocateArray node and its ValidLengthTest input that could cause
2296 // split if to break.
2297 if (use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque4 ||
2298 (use->Opcode() == Op_AllocateArray && use->in(AllocateNode::ValidLengthTest) == old)) {
2299 // Since this code is highly unlikely, we lazily build the worklist
2300 // of such Nodes to go split.
2301 if (!split_if_set) {
2302 split_if_set = new Node_List();
2303 }
2304 split_if_set->push(use);
2305 }
2306 if (use->is_Bool()) {
2307 if (!split_bool_set) {
2308 split_bool_set = new Node_List();
2309 }
2310 split_bool_set->push(use);
2311 }
2312 if (use->Opcode() == Op_CreateEx) {
2313 if (!split_cex_set) {
2314 split_cex_set = new Node_List();
2315 }
2316 split_cex_set->push(use);
2317 }
2318
2319
2320 // Get "block" use is in
2321 uint idx = 0;
2322 while( use->in(idx) != old ) idx++;
2323 Node *prev = use->is_CFG() ? use : get_ctrl(use);
2324 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
2325 Node *cfg = prev->_idx >= new_counter
2326 ? prev->in(2)
2327 : idom(prev);
2328 if( use->is_Phi() ) // Phi use is in prior block
2329 cfg = prev->in(idx); // NOT in block of Phi itself
2330 if (cfg->is_top()) { // Use is dead?
2331 _igvn.replace_input_of(use, idx, C->top());
2332 continue;
2333 }
2334
2335 // If use is referenced through control edge... (idx == 0)
2336 if (mode == IgnoreStripMined && idx == 0) {
2337 LoopNode *head = loop->_head->as_Loop();
2338 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
2339 // That node is outside the inner loop, leave it outside the
2340 // outer loop as well to not confuse verification code.
2341 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
2342 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
2343 continue;
2344 }
2345 }
2346
2347 while(!outer_loop->is_member(get_loop(cfg))) {
2348 prev = cfg;
2349 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
2350 }
2351 // If the use occurs after merging several exits from the loop, then
2352 // old value must have dominated all those exits. Since the same old
2353 // value was used on all those exits we did not need a Phi at this
2354 // merge point. NOW we do need a Phi here. Each loop exit value
2355 // is now merged with the peeled body exit; each exit gets its own
2356 // private Phi and those Phis need to be merged here.
2357 Node *phi;
2358 if( prev->is_Region() ) {
2359 if( idx == 0 ) { // Updating control edge?
2360 phi = prev; // Just use existing control
2361 } else { // Else need a new Phi
2362 phi = PhiNode::make( prev, old );
2363 // Now recursively fix up the new uses of old!
2364 for( uint i = 1; i < prev->req(); i++ ) {
2365 worklist.push(phi); // Onto worklist once for each 'old' input
2366 }
2367 }
2368 } else {
2369 // Get new RegionNode merging old and new loop exits
2370 prev = old_new[prev->_idx];
2371 assert( prev, "just made this in step 7" );
2372 if( idx == 0) { // Updating control edge?
2373 phi = prev; // Just use existing control
2374 } else { // Else need a new Phi
2375 // Make a new Phi merging data values properly
2376 phi = PhiNode::make( prev, old );
2377 phi->set_req( 1, nnn );
2378 }
2379 }
2380 // If inserting a new Phi, check for prior hits
2381 if( idx != 0 ) {
2382 Node *hit = _igvn.hash_find_insert(phi);
2383 if( hit == nullptr ) {
2384 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2385 } else { // or
2386 // Remove the new phi from the graph and use the hit
2387 _igvn.remove_dead_node(phi);
2388 phi = hit; // Use existing phi
2389 }
2390 set_ctrl(phi, prev);
2391 }
2392 // Make 'use' use the Phi instead of the old loop body exit value
2393 assert(use->in(idx) == old, "old is still input of use");
2394 // We notify all uses of old, including use, and the indirect uses,
2395 // that may now be optimized because we have replaced old with phi.
2396 _igvn.add_users_to_worklist(old);
2397 _igvn.replace_input_of(use, idx, phi);
2398 if( use->_idx >= new_counter ) { // If updating new phis
2399 // Not needed for correctness, but prevents a weak assert
2400 // in AddPNode from tripping (when we end up with different
2401 // base & derived Phis that will become the same after
2402 // IGVN does CSE).
2403 Node *hit = _igvn.hash_find_insert(use);
2404 if( hit ) // Go ahead and re-hash for hits.
2405 _igvn.replace_node( use, hit );
2406 }
2407
2408 // If 'use' was in the loop-exit block, it now needs to be sunk
2409 // below the post-loop merge point.
2410 sink_use( use, prev );
2411 }
2412 }
2413 }
2414
2415 static void collect_nodes_in_outer_loop_not_reachable_from_sfpt(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop,
2416 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase,
2417 bool check_old_new) {
2418 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2419 Node* u = n->fast_out(j);
2420 assert(check_old_new || old_new[u->_idx] == nullptr, "shouldn't have been cloned");
2421 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == nullptr)) {
2422 Node* c = phase->get_ctrl(u);
2423 IdealLoopTree* u_loop = phase->get_loop(c);
2424 assert(!loop->is_member(u_loop) || !loop->_body.contains(u), "can be in outer loop or out of both loops only");
2425 if (!loop->is_member(u_loop)) {
2426 if (outer_loop->is_member(u_loop)) {
2427 wq.push(u);
2428 } else {
2429 // nodes pinned with control in the outer loop but not referenced from the safepoint must be moved out of
2430 // the outer loop too
2431 Node* u_c = u->in(0);
2432 if (u_c != nullptr) {
2433 IdealLoopTree* u_c_loop = phase->get_loop(u_c);
2434 if (outer_loop->is_member(u_c_loop) && !loop->is_member(u_c_loop)) {
2435 wq.push(u);
2436 }
2437 }
2438 }
2439 }
2440 }
2441 }
2442 }
2443
2444 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2445 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2446 Node_List& extra_data_nodes) {
2447 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2448 CountedLoopNode* cl = head->as_CountedLoop();
2449 Node* l = cl->outer_loop();
2450 Node* tail = cl->outer_loop_tail();
2451 IfNode* le = cl->outer_loop_end();
2452 Node* sfpt = cl->outer_safepoint();
2453 CountedLoopEndNode* cle = cl->loopexit();
2454 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2455 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2456 Node* cle_out = cle->proj_out(false);
2457
2458 Node* new_sfpt = nullptr;
2459 Node* new_cle_out = cle_out->clone();
2460 old_new.map(cle_out->_idx, new_cle_out);
2461 if (mode == CloneIncludesStripMined) {
2462 // clone outer loop body
2463 Node* new_l = l->clone();
2464 Node* new_tail = tail->clone();
2465 IfNode* new_le = le->clone()->as_If();
2466 new_sfpt = sfpt->clone();
2467
2468 set_loop(new_l, outer_loop->_parent);
2469 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2470 set_loop(new_cle_out, outer_loop->_parent);
2471 set_idom(new_cle_out, new_cle, dd);
2472 set_loop(new_sfpt, outer_loop->_parent);
2473 set_idom(new_sfpt, new_cle_out, dd);
2474 set_loop(new_le, outer_loop->_parent);
2475 set_idom(new_le, new_sfpt, dd);
2476 set_loop(new_tail, outer_loop->_parent);
2477 set_idom(new_tail, new_le, dd);
2478 set_idom(new_cl, new_l, dd);
2479
2480 old_new.map(l->_idx, new_l);
2481 old_new.map(tail->_idx, new_tail);
2482 old_new.map(le->_idx, new_le);
2483 old_new.map(sfpt->_idx, new_sfpt);
2484
2485 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2486 new_l->set_req(0, new_l);
2487 new_tail->set_req(0, new_le);
2488 new_le->set_req(0, new_sfpt);
2489 new_sfpt->set_req(0, new_cle_out);
2490 new_cle_out->set_req(0, new_cle);
2491 new_cl->set_req(LoopNode::EntryControl, new_l);
2492
2493 _igvn.register_new_node_with_optimizer(new_l);
2494 _igvn.register_new_node_with_optimizer(new_tail);
2495 _igvn.register_new_node_with_optimizer(new_le);
2496 } else {
2497 Node *newhead = old_new[loop->_head->_idx];
2498 newhead->as_Loop()->clear_strip_mined();
2499 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2500 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2501 }
2502 // Look at data node that were assigned a control in the outer
2503 // loop: they are kept in the outer loop by the safepoint so start
2504 // from the safepoint node's inputs.
2505 IdealLoopTree* outer_loop = get_loop(l);
2506 Node_Stack stack(2);
2507 stack.push(sfpt, 1);
2508 uint new_counter = C->unique();
2509 while (stack.size() > 0) {
2510 Node* n = stack.node();
2511 uint i = stack.index();
2512 while (i < n->req() &&
2513 (n->in(i) == nullptr ||
2514 !has_ctrl(n->in(i)) ||
2515 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2516 (old_new[n->in(i)->_idx] != nullptr && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2517 i++;
2518 }
2519 if (i < n->req()) {
2520 stack.set_index(i+1);
2521 stack.push(n->in(i), 0);
2522 } else {
2523 assert(old_new[n->_idx] == nullptr || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2524 Node* m = n == sfpt ? new_sfpt : n->clone();
2525 if (m != nullptr) {
2526 for (uint i = 0; i < n->req(); i++) {
2527 if (m->in(i) != nullptr && old_new[m->in(i)->_idx] != nullptr) {
2528 m->set_req(i, old_new[m->in(i)->_idx]);
2529 }
2530 }
2531 } else {
2532 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2533 }
2534 if (n != sfpt) {
2535 extra_data_nodes.push(n);
2536 _igvn.register_new_node_with_optimizer(m);
2537 assert(get_ctrl(n) == cle_out, "what other control?");
2538 set_ctrl(m, new_cle_out);
2539 old_new.map(n->_idx, m);
2540 }
2541 stack.pop();
2542 }
2543 }
2544 if (mode == CloneIncludesStripMined) {
2545 _igvn.register_new_node_with_optimizer(new_sfpt);
2546 _igvn.register_new_node_with_optimizer(new_cle_out);
2547 }
2548 // Some other transformation may have pessimistically assigned some
2549 // data nodes to the outer loop. Set their control so they are out
2550 // of the outer loop.
2551 ResourceMark rm;
2552 Unique_Node_List wq;
2553 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2554 Node* old = extra_data_nodes.at(i);
2555 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2556 }
2557
2558 for (uint i = 0; i < loop->_body.size(); i++) {
2559 Node* old = loop->_body.at(i);
2560 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2561 }
2562
2563 Node* inner_out = sfpt->in(0);
2564 if (inner_out->outcnt() > 1) {
2565 collect_nodes_in_outer_loop_not_reachable_from_sfpt(inner_out, loop, outer_loop, old_new, wq, this, true);
2566 }
2567
2568 Node* new_ctrl = cl->outer_loop_exit();
2569 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest");
2570 for (uint i = 0; i < wq.size(); i++) {
2571 Node* n = wq.at(i);
2572 set_ctrl(n, new_ctrl);
2573 if (n->in(0) != nullptr) {
2574 _igvn.replace_input_of(n, 0, new_ctrl);
2575 }
2576 collect_nodes_in_outer_loop_not_reachable_from_sfpt(n, loop, outer_loop, old_new, wq, this, false);
2577 }
2578 } else {
2579 Node *newhead = old_new[loop->_head->_idx];
2580 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2581 }
2582 }
2583
2584 //------------------------------clone_loop-------------------------------------
2585 //
2586 // C L O N E A L O O P B O D Y
2587 //
2588 // This is the basic building block of the loop optimizations. It clones an
2589 // entire loop body. It makes an old_new loop body mapping; with this mapping
2590 // you can find the new-loop equivalent to an old-loop node. All new-loop
2591 // nodes are exactly equal to their old-loop counterparts, all edges are the
2592 // same. All exits from the old-loop now have a RegionNode that merges the
2593 // equivalent new-loop path. This is true even for the normal "loop-exit"
2594 // condition. All uses of loop-invariant old-loop values now come from (one
2595 // or more) Phis that merge their new-loop equivalents.
2596 //
2597 // This operation leaves the graph in an illegal state: there are two valid
2598 // control edges coming from the loop pre-header to both loop bodies. I'll
2599 // definitely have to hack the graph after running this transform.
2600 //
2601 // From this building block I will further edit edges to perform loop peeling
2602 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2603 //
2604 // Parameter side_by_size_idom:
2605 // When side_by_size_idom is null, the dominator tree is constructed for
2606 // the clone loop to dominate the original. Used in construction of
2607 // pre-main-post loop sequence.
2608 // When nonnull, the clone and original are side-by-side, both are
2609 // dominated by the side_by_side_idom node. Used in construction of
2610 // unswitched loops.
2611 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2612 CloneLoopMode mode, Node* side_by_side_idom) {
2613
2614 LoopNode* head = loop->_head->as_Loop();
2615 head->verify_strip_mined(1);
2616
2617 if (C->do_vector_loop() && PrintOpto) {
2618 const char* mname = C->method()->name()->as_quoted_ascii();
2619 if (mname != nullptr) {
2620 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2621 }
2622 }
2623
2624 CloneMap& cm = C->clone_map();
2625 if (C->do_vector_loop()) {
2626 cm.set_clone_idx(cm.max_gen()+1);
2627 #ifndef PRODUCT
2628 if (PrintOpto) {
2629 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2630 loop->dump_head();
2631 }
2632 #endif
2633 }
2634
2635 // Step 1: Clone the loop body. Make the old->new mapping.
2636 clone_loop_body(loop->_body, old_new, &cm);
2637
2638 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2639
2640 // Step 2: Fix the edges in the new body. If the old input is outside the
2641 // loop use it. If the old input is INside the loop, use the corresponding
2642 // new node instead.
2643 fix_body_edges(loop->_body, loop, old_new, dd, outer_loop->_parent, false);
2644
2645 Node_List extra_data_nodes; // data nodes in the outer strip mined loop
2646 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2647
2648 // Step 3: Now fix control uses. Loop varying control uses have already
2649 // been fixed up (as part of all input edges in Step 2). Loop invariant
2650 // control uses must be either an IfFalse or an IfTrue. Make a merge
2651 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2652 // refer to this.
2653 Node_List worklist;
2654 uint new_counter = C->unique();
2655 fix_ctrl_uses(loop->_body, loop, old_new, mode, side_by_side_idom, &cm, worklist);
2656
2657 // Step 4: If loop-invariant use is not control, it must be dominated by a
2658 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2659 // there if needed. Make a Phi there merging old and new used values.
2660 Node_List *split_if_set = nullptr;
2661 Node_List *split_bool_set = nullptr;
2662 Node_List *split_cex_set = nullptr;
2663 fix_data_uses(loop->_body, loop, mode, outer_loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
2664
2665 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2666 Node* old = extra_data_nodes.at(i);
2667 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2668 split_bool_set, split_cex_set, worklist, new_counter,
2669 mode);
2670 }
2671
2672 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2673 // the loop uses a condition set in the loop. The original IF probably
2674 // takes control from one or more OLD Regions (which in turn get from NEW
2675 // Regions). In any case, there will be a set of Phis for each merge point
2676 // from the IF up to where the original BOOL def exists the loop.
2677 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
2678
2679 }
2680
2681 void PhaseIdealLoop::finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set) {
2682 if (split_if_set) {
2683 while (split_if_set->size()) {
2684 Node *iff = split_if_set->pop();
2685 uint input = iff->Opcode() == Op_AllocateArray ? AllocateNode::ValidLengthTest : 1;
2686 if (iff->in(input)->is_Phi()) {
2687 Node *b = clone_iff(iff->in(input)->as_Phi());
2688 _igvn.replace_input_of(iff, input, b);
2689 }
2690 }
2691 }
2692 if (split_bool_set) {
2693 while (split_bool_set->size()) {
2694 Node *b = split_bool_set->pop();
2695 Node *phi = b->in(1);
2696 assert(phi->is_Phi(), "");
2697 CmpNode *cmp = clone_bool((PhiNode*) phi);
2698 _igvn.replace_input_of(b, 1, cmp);
2699 }
2700 }
2701 if (split_cex_set) {
2702 while (split_cex_set->size()) {
2703 Node *b = split_cex_set->pop();
2704 assert(b->in(0)->is_Region(), "");
2705 assert(b->in(1)->is_Phi(), "");
2706 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2707 split_up(b, b->in(0), nullptr);
2708 }
2709 }
2710 }
2711
2712 void PhaseIdealLoop::fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop,
2713 uint new_counter, Node_List &old_new, Node_List &worklist, Node_List*& split_if_set,
2714 Node_List*& split_bool_set, Node_List*& split_cex_set) {
2715 for(uint i = 0; i < body.size(); i++ ) {
2716 Node* old = body.at(i);
2717 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2718 split_bool_set, split_cex_set, worklist, new_counter,
2719 mode);
2720 }
2721 }
2722
2723 void PhaseIdealLoop::fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode,
2724 Node* side_by_side_idom, CloneMap* cm, Node_List &worklist) {
2725 LoopNode* head = loop->_head->as_Loop();
2726 for(uint i = 0; i < body.size(); i++ ) {
2727 Node* old = body.at(i);
2728 if( !old->is_CFG() ) continue;
2729
2730 // Copy uses to a worklist, so I can munge the def-use info
2731 // with impunity.
2732 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) {
2733 worklist.push(old->fast_out(j));
2734 }
2735
2736 while (worklist.size()) { // Visit all uses
2737 Node *use = worklist.pop();
2738 if (!has_node(use)) continue; // Ignore dead nodes
2739 IdealLoopTree *use_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use );
2740 if (!loop->is_member(use_loop) && use->is_CFG()) {
2741 // Both OLD and USE are CFG nodes here.
2742 assert(use->is_Proj(), "" );
2743 Node* nnn = old_new[old->_idx];
2744
2745 Node* newuse = nullptr;
2746 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2747 CountedLoopNode* cl = head->as_CountedLoop();
2748 CountedLoopEndNode* cle = cl->loopexit();
2749 Node* cle_out = cle->proj_out_or_null(false);
2750 if (use == cle_out) {
2751 IfNode* le = cl->outer_loop_end();
2752 use = le->proj_out(false);
2753 use_loop = get_loop(use);
2754 if (mode == CloneIncludesStripMined) {
2755 nnn = old_new[le->_idx];
2756 } else {
2757 newuse = old_new[cle_out->_idx];
2758 }
2759 }
2760 }
2761 if (newuse == nullptr) {
2762 newuse = use->clone();
2763 }
2764
2765 // Clone the loop exit control projection
2766 if (C->do_vector_loop() && cm != nullptr) {
2767 cm->verify_insert_and_clone(use, newuse, cm->clone_idx());
2768 }
2769 newuse->set_req(0,nnn);
2770 _igvn.register_new_node_with_optimizer(newuse);
2771 set_loop(newuse, use_loop);
2772 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2773
2774 // We need a Region to merge the exit from the peeled body and the
2775 // exit from the old loop body.
2776 RegionNode *r = new RegionNode(3);
2777 // Map the old use to the new merge point
2778 old_new.map( use->_idx, r );
2779 uint dd_r = MIN2(dom_depth(newuse), dom_depth(use));
2780 assert(dd_r >= dom_depth(dom_lca(newuse, use)), "" );
2781
2782 // The original user of 'use' uses 'r' instead.
2783 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2784 Node* useuse = use->last_out(l);
2785 _igvn.rehash_node_delayed(useuse);
2786 uint uses_found = 0;
2787 if (useuse->in(0) == use) {
2788 useuse->set_req(0, r);
2789 uses_found++;
2790 if (useuse->is_CFG()) {
2791 // This is not a dom_depth > dd_r because when new
2792 // control flow is constructed by a loop opt, a node and
2793 // its dominator can end up at the same dom_depth
2794 assert(dom_depth(useuse) >= dd_r, "");
2795 set_idom(useuse, r, dom_depth(useuse));
2796 }
2797 }
2798 for (uint k = 1; k < useuse->req(); k++) {
2799 if( useuse->in(k) == use ) {
2800 useuse->set_req(k, r);
2801 uses_found++;
2802 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2803 // This is not a dom_depth > dd_r because when new
2804 // control flow is constructed by a loop opt, a node
2805 // and its dominator can end up at the same dom_depth
2806 assert(dom_depth(useuse) >= dd_r , "");
2807 set_idom(useuse, r, dom_depth(useuse));
2808 }
2809 }
2810 }
2811 l -= uses_found; // we deleted 1 or more copies of this edge
2812 }
2813
2814 // Now finish up 'r'
2815 r->set_req(1, newuse);
2816 r->set_req(2, use);
2817 _igvn.register_new_node_with_optimizer(r);
2818 set_loop(r, use_loop);
2819 set_idom(r, (side_by_side_idom == nullptr) ? newuse->in(0) : side_by_side_idom, dd_r);
2820 } // End of if a loop-exit test
2821 }
2822 }
2823 }
2824
2825 void PhaseIdealLoop::fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd,
2826 IdealLoopTree* parent, bool partial) {
2827 for(uint i = 0; i < body.size(); i++ ) {
2828 Node *old = body.at(i);
2829 Node *nnn = old_new[old->_idx];
2830 // Fix CFG/Loop controlling the new node
2831 if (has_ctrl(old)) {
2832 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2833 } else {
2834 set_loop(nnn, parent);
2835 if (old->outcnt() > 0) {
2836 Node* dom = idom(old);
2837 if (old_new[dom->_idx] != nullptr) {
2838 dom = old_new[dom->_idx];
2839 set_idom(nnn, dom, dd );
2840 }
2841 }
2842 }
2843 // Correct edges to the new node
2844 for (uint j = 0; j < nnn->req(); j++) {
2845 Node *n = nnn->in(j);
2846 if (n != nullptr) {
2847 IdealLoopTree *old_in_loop = get_loop(has_ctrl(n) ? get_ctrl(n) : n);
2848 if (loop->is_member(old_in_loop)) {
2849 if (old_new[n->_idx] != nullptr) {
2850 nnn->set_req(j, old_new[n->_idx]);
2851 } else {
2852 assert(!body.contains(n), "");
2853 assert(partial, "node not cloned");
2854 }
2855 }
2856 }
2857 }
2858 _igvn.hash_find_insert(nnn);
2859 }
2860 }
2861
2862 void PhaseIdealLoop::clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm) {
2863 for (uint i = 0; i < body.size(); i++) {
2864 Node* old = body.at(i);
2865 Node* nnn = old->clone();
2866 old_new.map(old->_idx, nnn);
2867 if (C->do_vector_loop() && cm != nullptr) {
2868 cm->verify_insert_and_clone(old, nnn, cm->clone_idx());
2869 }
2870 _igvn.register_new_node_with_optimizer(nnn);
2871 }
2872 }
2873
2874
2875 //---------------------- stride_of_possible_iv -------------------------------------
2876 // Looks for an iff/bool/comp with one operand of the compare
2877 // being a cycle involving an add and a phi,
2878 // with an optional truncation (left-shift followed by a right-shift)
2879 // of the add. Returns zero if not an iv.
2880 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2881 Node* trunc1 = nullptr;
2882 Node* trunc2 = nullptr;
2883 const TypeInteger* ttype = nullptr;
2884 if (!iff->is_If() || iff->in(1) == nullptr || !iff->in(1)->is_Bool()) {
2885 return 0;
2886 }
2887 BoolNode* bl = iff->in(1)->as_Bool();
2888 Node* cmp = bl->in(1);
2889 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2890 return 0;
2891 }
2892 // Must have an invariant operand
2893 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2894 return 0;
2895 }
2896 Node* add2 = nullptr;
2897 Node* cmp1 = cmp->in(1);
2898 if (cmp1->is_Phi()) {
2899 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2900 Node* phi = cmp1;
2901 for (uint i = 1; i < phi->req(); i++) {
2902 Node* in = phi->in(i);
2903 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2904 &trunc1, &trunc2, &ttype, T_INT);
2905 if (add && add->in(1) == phi) {
2906 add2 = add->in(2);
2907 break;
2908 }
2909 }
2910 } else {
2911 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2912 Node* addtrunc = cmp1;
2913 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2914 &trunc1, &trunc2, &ttype, T_INT);
2915 if (add && add->in(1)->is_Phi()) {
2916 Node* phi = add->in(1);
2917 for (uint i = 1; i < phi->req(); i++) {
2918 if (phi->in(i) == addtrunc) {
2919 add2 = add->in(2);
2920 break;
2921 }
2922 }
2923 }
2924 }
2925 if (add2 != nullptr) {
2926 const TypeInt* add2t = _igvn.type(add2)->is_int();
2927 if (add2t->is_con()) {
2928 return add2t->get_con();
2929 }
2930 }
2931 return 0;
2932 }
2933
2934
2935 //---------------------- stay_in_loop -------------------------------------
2936 // Return the (unique) control output node that's in the loop (if it exists.)
2937 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2938 Node* unique = nullptr;
2939 if (!n) return nullptr;
2940 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2941 Node* use = n->fast_out(i);
2942 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2943 if (unique != nullptr) {
2944 return nullptr;
2945 }
2946 unique = use;
2947 }
2948 }
2949 return unique;
2950 }
2951
2952 //------------------------------ register_node -------------------------------------
2953 // Utility to register node "n" with PhaseIdealLoop
2954 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree* loop, Node* pred, uint ddepth) {
2955 _igvn.register_new_node_with_optimizer(n);
2956 loop->_body.push(n);
2957 if (n->is_CFG()) {
2958 set_loop(n, loop);
2959 set_idom(n, pred, ddepth);
2960 } else {
2961 set_ctrl(n, pred);
2962 }
2963 }
2964
2965 //------------------------------ proj_clone -------------------------------------
2966 // Utility to create an if-projection
2967 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2968 ProjNode* c = p->clone()->as_Proj();
2969 c->set_req(0, iff);
2970 return c;
2971 }
2972
2973 //------------------------------ short_circuit_if -------------------------------------
2974 // Force the iff control output to be the live_proj
2975 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2976 guarantee(live_proj != nullptr, "null projection");
2977 int proj_con = live_proj->_con;
2978 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2979 Node *con = _igvn.intcon(proj_con);
2980 set_ctrl(con, C->root());
2981 if (iff) {
2982 iff->set_req(1, con);
2983 }
2984 return con;
2985 }
2986
2987 //------------------------------ insert_if_before_proj -------------------------------------
2988 // Insert a new if before an if projection (* - new node)
2989 //
2990 // before
2991 // if(test)
2992 // / \
2993 // v v
2994 // other-proj proj (arg)
2995 //
2996 // after
2997 // if(test)
2998 // / \
2999 // / v
3000 // | * proj-clone
3001 // v |
3002 // other-proj v
3003 // * new_if(relop(cmp[IU](left,right)))
3004 // / \
3005 // v v
3006 // * new-proj proj
3007 // (returned)
3008 //
3009 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
3010 IfNode* iff = proj->in(0)->as_If();
3011 IdealLoopTree *loop = get_loop(proj);
3012 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
3013 uint ddepth = dom_depth(proj);
3014
3015 _igvn.rehash_node_delayed(iff);
3016 _igvn.rehash_node_delayed(proj);
3017
3018 proj->set_req(0, nullptr); // temporary disconnect
3019 ProjNode* proj2 = proj_clone(proj, iff);
3020 register_node(proj2, loop, iff, ddepth);
3021
3022 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
3023 register_node(cmp, loop, proj2, ddepth);
3024
3025 BoolNode* bol = new BoolNode(cmp, relop);
3026 register_node(bol, loop, proj2, ddepth);
3027
3028 int opcode = iff->Opcode();
3029 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
3030 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
3031 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
3032 register_node(new_if, loop, proj2, ddepth);
3033
3034 proj->set_req(0, new_if); // reattach
3035 set_idom(proj, new_if, ddepth);
3036
3037 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
3038 guarantee(new_exit != nullptr, "null exit node");
3039 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
3040
3041 return new_exit;
3042 }
3043
3044 //------------------------------ insert_region_before_proj -------------------------------------
3045 // Insert a region before an if projection (* - new node)
3046 //
3047 // before
3048 // if(test)
3049 // / |
3050 // v |
3051 // proj v
3052 // other-proj
3053 //
3054 // after
3055 // if(test)
3056 // / |
3057 // v |
3058 // * proj-clone v
3059 // | other-proj
3060 // v
3061 // * new-region
3062 // |
3063 // v
3064 // * dum_if
3065 // / \
3066 // v \
3067 // * dum-proj v
3068 // proj
3069 //
3070 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
3071 IfNode* iff = proj->in(0)->as_If();
3072 IdealLoopTree *loop = get_loop(proj);
3073 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
3074 uint ddepth = dom_depth(proj);
3075
3076 _igvn.rehash_node_delayed(iff);
3077 _igvn.rehash_node_delayed(proj);
3078
3079 proj->set_req(0, nullptr); // temporary disconnect
3080 ProjNode* proj2 = proj_clone(proj, iff);
3081 register_node(proj2, loop, iff, ddepth);
3082
3083 RegionNode* reg = new RegionNode(2);
3084 reg->set_req(1, proj2);
3085 register_node(reg, loop, iff, ddepth);
3086
3087 IfNode* dum_if = new IfNode(reg, short_circuit_if(nullptr, proj), iff->_prob, iff->_fcnt);
3088 register_node(dum_if, loop, reg, ddepth);
3089
3090 proj->set_req(0, dum_if); // reattach
3091 set_idom(proj, dum_if, ddepth);
3092
3093 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
3094 register_node(dum_proj, loop, dum_if, ddepth);
3095
3096 return reg;
3097 }
3098
3099 //------------------------------ insert_cmpi_loop_exit -------------------------------------
3100 // Clone a signed compare loop exit from an unsigned compare and
3101 // insert it before the unsigned cmp on the stay-in-loop path.
3102 // All new nodes inserted in the dominator tree between the original
3103 // if and it's projections. The original if test is replaced with
3104 // a constant to force the stay-in-loop path.
3105 //
3106 // This is done to make sure that the original if and it's projections
3107 // still dominate the same set of control nodes, that the ctrl() relation
3108 // from data nodes to them is preserved, and that their loop nesting is
3109 // preserved.
3110 //
3111 // before
3112 // if(i <u limit) unsigned compare loop exit
3113 // / |
3114 // v v
3115 // exit-proj stay-in-loop-proj
3116 //
3117 // after
3118 // if(stay-in-loop-const) original if
3119 // / |
3120 // / v
3121 // / if(i < limit) new signed test
3122 // / / |
3123 // / / v
3124 // / / if(i <u limit) new cloned unsigned test
3125 // / / / |
3126 // v v v |
3127 // region |
3128 // | |
3129 // dum-if |
3130 // / | |
3131 // ether | |
3132 // v v
3133 // exit-proj stay-in-loop-proj
3134 //
3135 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
3136 const bool Signed = true;
3137 const bool Unsigned = false;
3138
3139 BoolNode* bol = if_cmpu->in(1)->as_Bool();
3140 if (bol->_test._test != BoolTest::lt) return nullptr;
3141 CmpNode* cmpu = bol->in(1)->as_Cmp();
3142 if (cmpu->Opcode() != Op_CmpU) return nullptr;
3143 int stride = stride_of_possible_iv(if_cmpu);
3144 if (stride == 0) return nullptr;
3145
3146 Node* lp_proj = stay_in_loop(if_cmpu, loop);
3147 guarantee(lp_proj != nullptr, "null loop node");
3148
3149 ProjNode* lp_continue = lp_proj->as_Proj();
3150 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
3151 if (!lp_exit->is_IfFalse()) {
3152 // The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit).
3153 // We therefore can't add a single exit condition.
3154 return nullptr;
3155 }
3156 // The loop exit condition is !(i <u limit) ==> (i < 0 || i >= limit).
3157 // Split out the exit condition (i < 0) for stride < 0 or (i >= limit) for stride > 0.
3158 Node* limit = nullptr;
3159 if (stride > 0) {
3160 limit = cmpu->in(2);
3161 } else {
3162 limit = _igvn.makecon(TypeInt::ZERO);
3163 set_ctrl(limit, C->root());
3164 }
3165 // Create a new region on the exit path
3166 RegionNode* reg = insert_region_before_proj(lp_exit);
3167 guarantee(reg != nullptr, "null region node");
3168
3169 // Clone the if-cmpu-true-false using a signed compare
3170 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
3171 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
3172 reg->add_req(cmpi_exit);
3173
3174 // Clone the if-cmpu-true-false
3175 BoolTest::mask rel_u = bol->_test._test;
3176 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
3177 reg->add_req(cmpu_exit);
3178
3179 // Force original if to stay in loop.
3180 short_circuit_if(if_cmpu, lp_continue);
3181
3182 return cmpi_exit->in(0)->as_If();
3183 }
3184
3185 //------------------------------ remove_cmpi_loop_exit -------------------------------------
3186 // Remove a previously inserted signed compare loop exit.
3187 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
3188 Node* lp_proj = stay_in_loop(if_cmp, loop);
3189 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
3190 stay_in_loop(lp_proj, loop)->is_If() &&
3191 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
3192 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
3193 set_ctrl(con, C->root());
3194 if_cmp->set_req(1, con);
3195 }
3196
3197 //------------------------------ scheduled_nodelist -------------------------------------
3198 // Create a post order schedule of nodes that are in the
3199 // "member" set. The list is returned in "sched".
3200 // The first node in "sched" is the loop head, followed by
3201 // nodes which have no inputs in the "member" set, and then
3202 // followed by the nodes that have an immediate input dependence
3203 // on a node in "sched".
3204 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
3205
3206 assert(member.test(loop->_head->_idx), "loop head must be in member set");
3207 VectorSet visited;
3208 Node_Stack nstack(loop->_body.size());
3209
3210 Node* n = loop->_head; // top of stack is cached in "n"
3211 uint idx = 0;
3212 visited.set(n->_idx);
3213
3214 // Initially push all with no inputs from within member set
3215 for(uint i = 0; i < loop->_body.size(); i++ ) {
3216 Node *elt = loop->_body.at(i);
3217 if (member.test(elt->_idx)) {
3218 bool found = false;
3219 for (uint j = 0; j < elt->req(); j++) {
3220 Node* def = elt->in(j);
3221 if (def && member.test(def->_idx) && def != elt) {
3222 found = true;
3223 break;
3224 }
3225 }
3226 if (!found && elt != loop->_head) {
3227 nstack.push(n, idx);
3228 n = elt;
3229 assert(!visited.test(n->_idx), "not seen yet");
3230 visited.set(n->_idx);
3231 }
3232 }
3233 }
3234
3235 // traverse out's that are in the member set
3236 while (true) {
3237 if (idx < n->outcnt()) {
3238 Node* use = n->raw_out(idx);
3239 idx++;
3240 if (!visited.test_set(use->_idx)) {
3241 if (member.test(use->_idx)) {
3242 nstack.push(n, idx);
3243 n = use;
3244 idx = 0;
3245 }
3246 }
3247 } else {
3248 // All outputs processed
3249 sched.push(n);
3250 if (nstack.is_empty()) break;
3251 n = nstack.node();
3252 idx = nstack.index();
3253 nstack.pop();
3254 }
3255 }
3256 }
3257
3258
3259 //------------------------------ has_use_in_set -------------------------------------
3260 // Has a use in the vector set
3261 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
3262 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3263 Node* use = n->fast_out(j);
3264 if (vset.test(use->_idx)) {
3265 return true;
3266 }
3267 }
3268 return false;
3269 }
3270
3271
3272 //------------------------------ has_use_internal_to_set -------------------------------------
3273 // Has use internal to the vector set (ie. not in a phi at the loop head)
3274 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
3275 Node* head = loop->_head;
3276 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3277 Node* use = n->fast_out(j);
3278 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
3279 return true;
3280 }
3281 }
3282 return false;
3283 }
3284
3285
3286 //------------------------------ clone_for_use_outside_loop -------------------------------------
3287 // clone "n" for uses that are outside of loop
3288 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
3289 int cloned = 0;
3290 assert(worklist.size() == 0, "should be empty");
3291 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3292 Node* use = n->fast_out(j);
3293 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
3294 worklist.push(use);
3295 }
3296 }
3297
3298 if (C->check_node_count(worklist.size() + NodeLimitFudgeFactor,
3299 "Too many clones required in clone_for_use_outside_loop in partial peeling")) {
3300 return -1;
3301 }
3302
3303 while( worklist.size() ) {
3304 Node *use = worklist.pop();
3305 if (!has_node(use) || use->in(0) == C->top()) continue;
3306 uint j;
3307 for (j = 0; j < use->req(); j++) {
3308 if (use->in(j) == n) break;
3309 }
3310 assert(j < use->req(), "must be there");
3311
3312 // clone "n" and insert it between the inputs of "n" and the use outside the loop
3313 Node* n_clone = n->clone();
3314 _igvn.replace_input_of(use, j, n_clone);
3315 cloned++;
3316 Node* use_c;
3317 if (!use->is_Phi()) {
3318 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
3319 } else {
3320 // Use in a phi is considered a use in the associated predecessor block
3321 use_c = use->in(0)->in(j);
3322 }
3323 set_ctrl(n_clone, use_c);
3324 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
3325 get_loop(use_c)->_body.push(n_clone);
3326 _igvn.register_new_node_with_optimizer(n_clone);
3327 #ifndef PRODUCT
3328 if (TracePartialPeeling) {
3329 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
3330 }
3331 #endif
3332 }
3333 return cloned;
3334 }
3335
3336
3337 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
3338 // clone "n" for special uses that are in the not_peeled region.
3339 // If these def-uses occur in separate blocks, the code generator
3340 // marks the method as not compilable. For example, if a "BoolNode"
3341 // is in a different basic block than the "IfNode" that uses it, then
3342 // the compilation is aborted in the code generator.
3343 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
3344 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
3345 if (n->is_Phi() || n->is_Load()) {
3346 return;
3347 }
3348 assert(worklist.size() == 0, "should be empty");
3349 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3350 Node* use = n->fast_out(j);
3351 if ( not_peel.test(use->_idx) &&
3352 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
3353 use->in(1) == n) {
3354 worklist.push(use);
3355 }
3356 }
3357 if (worklist.size() > 0) {
3358 // clone "n" and insert it between inputs of "n" and the use
3359 Node* n_clone = n->clone();
3360 loop->_body.push(n_clone);
3361 _igvn.register_new_node_with_optimizer(n_clone);
3362 set_ctrl(n_clone, get_ctrl(n));
3363 sink_list.push(n_clone);
3364 not_peel.set(n_clone->_idx);
3365 #ifndef PRODUCT
3366 if (TracePartialPeeling) {
3367 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
3368 }
3369 #endif
3370 while( worklist.size() ) {
3371 Node *use = worklist.pop();
3372 _igvn.rehash_node_delayed(use);
3373 for (uint j = 1; j < use->req(); j++) {
3374 if (use->in(j) == n) {
3375 use->set_req(j, n_clone);
3376 }
3377 }
3378 }
3379 }
3380 }
3381
3382
3383 //------------------------------ insert_phi_for_loop -------------------------------------
3384 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
3385 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
3386 Node *phi = PhiNode::make(lp, back_edge_val);
3387 phi->set_req(LoopNode::EntryControl, lp_entry_val);
3388 // Use existing phi if it already exists
3389 Node *hit = _igvn.hash_find_insert(phi);
3390 if( hit == nullptr ) {
3391 _igvn.register_new_node_with_optimizer(phi);
3392 set_ctrl(phi, lp);
3393 } else {
3394 // Remove the new phi from the graph and use the hit
3395 _igvn.remove_dead_node(phi);
3396 phi = hit;
3397 }
3398 _igvn.replace_input_of(use, idx, phi);
3399 }
3400
3401 #ifdef ASSERT
3402 //------------------------------ is_valid_loop_partition -------------------------------------
3403 // Validate the loop partition sets: peel and not_peel
3404 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
3405 VectorSet& not_peel ) {
3406 uint i;
3407 // Check that peel_list entries are in the peel set
3408 for (i = 0; i < peel_list.size(); i++) {
3409 if (!peel.test(peel_list.at(i)->_idx)) {
3410 return false;
3411 }
3412 }
3413 // Check at loop members are in one of peel set or not_peel set
3414 for (i = 0; i < loop->_body.size(); i++ ) {
3415 Node *def = loop->_body.at(i);
3416 uint di = def->_idx;
3417 // Check that peel set elements are in peel_list
3418 if (peel.test(di)) {
3419 if (not_peel.test(di)) {
3420 return false;
3421 }
3422 // Must be in peel_list also
3423 bool found = false;
3424 for (uint j = 0; j < peel_list.size(); j++) {
3425 if (peel_list.at(j)->_idx == di) {
3426 found = true;
3427 break;
3428 }
3429 }
3430 if (!found) {
3431 return false;
3432 }
3433 } else if (not_peel.test(di)) {
3434 if (peel.test(di)) {
3435 return false;
3436 }
3437 } else {
3438 return false;
3439 }
3440 }
3441 return true;
3442 }
3443
3444 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
3445 // Ensure a use outside of loop is of the right form
3446 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
3447 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3448 return (use->is_Phi() &&
3449 use_c->is_Region() && use_c->req() == 3 &&
3450 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
3451 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
3452 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
3453 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
3454 }
3455
3456 //------------------------------ is_valid_clone_loop_form -------------------------------------
3457 // Ensure that all uses outside of loop are of the right form
3458 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
3459 uint orig_exit_idx, uint clone_exit_idx) {
3460 uint len = peel_list.size();
3461 for (uint i = 0; i < len; i++) {
3462 Node *def = peel_list.at(i);
3463
3464 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3465 Node *use = def->fast_out(j);
3466 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3467 if (!loop->is_member(get_loop(use_c))) {
3468 // use is not in the loop, check for correct structure
3469 if (use->in(0) == def) {
3470 // Okay
3471 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
3472 return false;
3473 }
3474 }
3475 }
3476 }
3477 return true;
3478 }
3479 #endif
3480
3481 //------------------------------ partial_peel -------------------------------------
3482 // Partially peel (aka loop rotation) the top portion of a loop (called
3483 // the peel section below) by cloning it and placing one copy just before
3484 // the new loop head and the other copy at the bottom of the new loop.
3485 //
3486 // before after where it came from
3487 //
3488 // stmt1 stmt1
3489 // loop: stmt2 clone
3490 // stmt2 if condA goto exitA clone
3491 // if condA goto exitA new_loop: new
3492 // stmt3 stmt3 clone
3493 // if !condB goto loop if condB goto exitB clone
3494 // exitB: stmt2 orig
3495 // stmt4 if !condA goto new_loop orig
3496 // exitA: goto exitA
3497 // exitB:
3498 // stmt4
3499 // exitA:
3500 //
3501 // Step 1: find the cut point: an exit test on probable
3502 // induction variable.
3503 // Step 2: schedule (with cloning) operations in the peel
3504 // section that can be executed after the cut into
3505 // the section that is not peeled. This may need
3506 // to clone operations into exit blocks. For
3507 // instance, a reference to A[i] in the not-peel
3508 // section and a reference to B[i] in an exit block
3509 // may cause a left-shift of i by 2 to be placed
3510 // in the peel block. This step will clone the left
3511 // shift into the exit block and sink the left shift
3512 // from the peel to the not-peel section.
3513 // Step 3: clone the loop, retarget the control, and insert
3514 // phis for values that are live across the new loop
3515 // head. This is very dependent on the graph structure
3516 // from clone_loop. It creates region nodes for
3517 // exit control and associated phi nodes for values
3518 // flow out of the loop through that exit. The region
3519 // node is dominated by the clone's control projection.
3520 // So the clone's peel section is placed before the
3521 // new loop head, and the clone's not-peel section is
3522 // forms the top part of the new loop. The original
3523 // peel section forms the tail of the new loop.
3524 // Step 4: update the dominator tree and recompute the
3525 // dominator depth.
3526 //
3527 // orig
3528 //
3529 // stmt1
3530 // |
3531 // v
3532 // predicates
3533 // |
3534 // v
3535 // loop<----+
3536 // | |
3537 // stmt2 |
3538 // | |
3539 // v |
3540 // ifA |
3541 // / | |
3542 // v v |
3543 // false true ^ <-- last_peel
3544 // / | |
3545 // / ===|==cut |
3546 // / stmt3 | <-- first_not_peel
3547 // / | |
3548 // | v |
3549 // v ifB |
3550 // exitA: / \ |
3551 // / \ |
3552 // v v |
3553 // false true |
3554 // / \ |
3555 // / ----+
3556 // |
3557 // v
3558 // exitB:
3559 // stmt4
3560 //
3561 //
3562 // after clone loop
3563 //
3564 // stmt1
3565 // |
3566 // v
3567 // predicates
3568 // / \
3569 // clone / \ orig
3570 // / \
3571 // / \
3572 // v v
3573 // +---->loop loop<----+
3574 // | | | |
3575 // | stmt2 stmt2 |
3576 // | | | |
3577 // | v v |
3578 // | ifA ifA |
3579 // | | \ / | |
3580 // | v v v v |
3581 // ^ true false false true ^ <-- last_peel
3582 // | | ^ \ / | |
3583 // | cut==|== \ \ / ===|==cut |
3584 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3585 // | | dom | | | |
3586 // | v \ 1v v2 v |
3587 // | ifB regionA ifB |
3588 // | / \ | / \ |
3589 // | / \ v / \ |
3590 // | v v exitA: v v |
3591 // | true false false true |
3592 // | / ^ \ / \ |
3593 // +---- \ \ / ----+
3594 // dom \ /
3595 // \ 1v v2
3596 // regionB
3597 // |
3598 // v
3599 // exitB:
3600 // stmt4
3601 //
3602 //
3603 // after partial peel
3604 //
3605 // stmt1
3606 // |
3607 // v
3608 // predicates
3609 // /
3610 // clone / orig
3611 // / TOP
3612 // / \
3613 // v v
3614 // TOP->loop loop----+
3615 // | | |
3616 // stmt2 stmt2 |
3617 // | | |
3618 // v v |
3619 // ifA ifA |
3620 // | \ / | |
3621 // v v v v |
3622 // true false false true | <-- last_peel
3623 // | ^ \ / +------|---+
3624 // +->newloop \ \ / === ==cut | |
3625 // | stmt3 \ \ / TOP | |
3626 // | | dom | | stmt3 | | <-- first_not_peel
3627 // | v \ 1v v2 v | |
3628 // | ifB regionA ifB ^ v
3629 // | / \ | / \ | |
3630 // | / \ v / \ | |
3631 // | v v exitA: v v | |
3632 // | true false false true | |
3633 // | / ^ \ / \ | |
3634 // | | \ \ / v | |
3635 // | | dom \ / TOP | |
3636 // | | \ 1v v2 | |
3637 // ^ v regionB | |
3638 // | | | | |
3639 // | | v ^ v
3640 // | | exitB: | |
3641 // | | stmt4 | |
3642 // | +------------>-----------------+ |
3643 // | |
3644 // +-----------------<---------------------+
3645 //
3646 //
3647 // final graph
3648 //
3649 // stmt1
3650 // |
3651 // v
3652 // predicates
3653 // |
3654 // v
3655 // stmt2 clone
3656 // |
3657 // v
3658 // ........> ifA clone
3659 // : / |
3660 // dom / |
3661 // : v v
3662 // : false true
3663 // : | |
3664 // : | v
3665 // : | newloop<-----+
3666 // : | | |
3667 // : | stmt3 clone |
3668 // : | | |
3669 // : | v |
3670 // : | ifB |
3671 // : | / \ |
3672 // : | v v |
3673 // : | false true |
3674 // : | | | |
3675 // : | v stmt2 |
3676 // : | exitB: | |
3677 // : | stmt4 v |
3678 // : | ifA orig |
3679 // : | / \ |
3680 // : | / \ |
3681 // : | v v |
3682 // : | false true |
3683 // : | / \ |
3684 // : v v -----+
3685 // RegionA
3686 // |
3687 // v
3688 // exitA
3689 //
3690 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3691
3692 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3693 if (!loop->_head->is_Loop()) {
3694 return false;
3695 }
3696 LoopNode *head = loop->_head->as_Loop();
3697
3698 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3699 return false;
3700 }
3701
3702 // Check for complex exit control
3703 for (uint ii = 0; ii < loop->_body.size(); ii++) {
3704 Node *n = loop->_body.at(ii);
3705 int opc = n->Opcode();
3706 if (n->is_Call() ||
3707 opc == Op_Catch ||
3708 opc == Op_CatchProj ||
3709 opc == Op_Jump ||
3710 opc == Op_JumpProj) {
3711 #ifndef PRODUCT
3712 if (TracePartialPeeling) {
3713 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3714 }
3715 #endif
3716 return false;
3717 }
3718 }
3719
3720 int dd = dom_depth(head);
3721
3722 // Step 1: find cut point
3723
3724 // Walk up dominators to loop head looking for first loop exit
3725 // which is executed on every path thru loop.
3726 IfNode *peel_if = nullptr;
3727 IfNode *peel_if_cmpu = nullptr;
3728
3729 Node *iff = loop->tail();
3730 while (iff != head) {
3731 if (iff->is_If()) {
3732 Node *ctrl = get_ctrl(iff->in(1));
3733 if (ctrl->is_top()) return false; // Dead test on live IF.
3734 // If loop-varying exit-test, check for induction variable
3735 if (loop->is_member(get_loop(ctrl)) &&
3736 loop->is_loop_exit(iff) &&
3737 is_possible_iv_test(iff)) {
3738 Node* cmp = iff->in(1)->in(1);
3739 if (cmp->Opcode() == Op_CmpI) {
3740 peel_if = iff->as_If();
3741 } else {
3742 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3743 peel_if_cmpu = iff->as_If();
3744 }
3745 }
3746 }
3747 iff = idom(iff);
3748 }
3749
3750 // Prefer signed compare over unsigned compare.
3751 IfNode* new_peel_if = nullptr;
3752 if (peel_if == nullptr) {
3753 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == nullptr) {
3754 return false; // No peel point found
3755 }
3756 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3757 if (new_peel_if == nullptr) {
3758 return false; // No peel point found
3759 }
3760 peel_if = new_peel_if;
3761 }
3762 Node* last_peel = stay_in_loop(peel_if, loop);
3763 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3764 if (first_not_peeled == nullptr || first_not_peeled == head) {
3765 return false;
3766 }
3767
3768 #ifndef PRODUCT
3769 if (TraceLoopOpts) {
3770 tty->print("PartialPeel ");
3771 loop->dump_head();
3772 }
3773
3774 if (TracePartialPeeling) {
3775 tty->print_cr("before partial peel one iteration");
3776 Node_List wl;
3777 Node* t = head->in(2);
3778 while (true) {
3779 wl.push(t);
3780 if (t == head) break;
3781 t = idom(t);
3782 }
3783 while (wl.size() > 0) {
3784 Node* tt = wl.pop();
3785 tt->dump();
3786 if (tt == last_peel) tty->print_cr("-- cut --");
3787 }
3788 }
3789 #endif
3790 VectorSet peel;
3791 VectorSet not_peel;
3792 Node_List peel_list;
3793 Node_List worklist;
3794 Node_List sink_list;
3795
3796 uint estimate = loop->est_loop_clone_sz(1);
3797 if (exceeding_node_budget(estimate)) {
3798 return false;
3799 }
3800
3801 // Set of cfg nodes to peel are those that are executable from
3802 // the head through last_peel.
3803 assert(worklist.size() == 0, "should be empty");
3804 worklist.push(head);
3805 peel.set(head->_idx);
3806 while (worklist.size() > 0) {
3807 Node *n = worklist.pop();
3808 if (n != last_peel) {
3809 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3810 Node* use = n->fast_out(j);
3811 if (use->is_CFG() &&
3812 loop->is_member(get_loop(use)) &&
3813 !peel.test_set(use->_idx)) {
3814 worklist.push(use);
3815 }
3816 }
3817 }
3818 }
3819
3820 // Set of non-cfg nodes to peel are those that are control
3821 // dependent on the cfg nodes.
3822 for (uint i = 0; i < loop->_body.size(); i++) {
3823 Node *n = loop->_body.at(i);
3824 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3825 if (peel.test(n_c->_idx)) {
3826 peel.set(n->_idx);
3827 } else {
3828 not_peel.set(n->_idx);
3829 }
3830 }
3831
3832 // Step 2: move operations from the peeled section down into the
3833 // not-peeled section
3834
3835 // Get a post order schedule of nodes in the peel region
3836 // Result in right-most operand.
3837 scheduled_nodelist(loop, peel, peel_list);
3838
3839 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3840
3841 // For future check for too many new phis
3842 uint old_phi_cnt = 0;
3843 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3844 Node* use = head->fast_out(j);
3845 if (use->is_Phi()) old_phi_cnt++;
3846 }
3847
3848 #ifndef PRODUCT
3849 if (TracePartialPeeling) {
3850 tty->print_cr("\npeeled list");
3851 }
3852 #endif
3853
3854 // Evacuate nodes in peel region into the not_peeled region if possible
3855 bool too_many_clones = false;
3856 uint new_phi_cnt = 0;
3857 uint cloned_for_outside_use = 0;
3858 for (uint i = 0; i < peel_list.size();) {
3859 Node* n = peel_list.at(i);
3860 #ifndef PRODUCT
3861 if (TracePartialPeeling) n->dump();
3862 #endif
3863 bool incr = true;
3864 if (!n->is_CFG()) {
3865 if (has_use_in_set(n, not_peel)) {
3866 // If not used internal to the peeled region,
3867 // move "n" from peeled to not_peeled region.
3868 if (!has_use_internal_to_set(n, peel, loop)) {
3869 // if not pinned and not a load (which maybe anti-dependent on a store)
3870 // and not a CMove (Matcher expects only bool->cmove).
3871 if (n->in(0) == nullptr && !n->is_Load() && !n->is_CMove()) {
3872 int new_clones = clone_for_use_outside_loop(loop, n, worklist);
3873 if (new_clones == -1) {
3874 too_many_clones = true;
3875 break;
3876 }
3877 cloned_for_outside_use += new_clones;
3878 sink_list.push(n);
3879 peel.remove(n->_idx);
3880 not_peel.set(n->_idx);
3881 peel_list.remove(i);
3882 incr = false;
3883 #ifndef PRODUCT
3884 if (TracePartialPeeling) {
3885 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3886 n->_idx, get_ctrl(n)->_idx);
3887 }
3888 #endif
3889 }
3890 } else {
3891 // Otherwise check for special def-use cases that span
3892 // the peel/not_peel boundary such as bool->if
3893 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist);
3894 new_phi_cnt++;
3895 }
3896 }
3897 }
3898 if (incr) i++;
3899 }
3900
3901 estimate += cloned_for_outside_use + new_phi_cnt;
3902 bool exceed_node_budget = !may_require_nodes(estimate);
3903 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta;
3904
3905 if (too_many_clones || exceed_node_budget || exceed_phi_limit) {
3906 #ifndef PRODUCT
3907 if (TracePartialPeeling && exceed_phi_limit) {
3908 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3909 new_phi_cnt, old_phi_cnt, new_peel_if != nullptr?'T':'F');
3910 }
3911 #endif
3912 if (new_peel_if != nullptr) {
3913 remove_cmpi_loop_exit(new_peel_if, loop);
3914 }
3915 // Inhibit more partial peeling on this loop
3916 assert(!head->is_partial_peel_loop(), "not partial peeled");
3917 head->mark_partial_peel_failed();
3918 if (cloned_for_outside_use > 0) {
3919 // Terminate this round of loop opts because
3920 // the graph outside this loop was changed.
3921 C->set_major_progress();
3922 return true;
3923 }
3924 return false;
3925 }
3926
3927 // Step 3: clone loop, retarget control, and insert new phis
3928
3929 // Create new loop head for new phis and to hang
3930 // the nodes being moved (sinked) from the peel region.
3931 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3932 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3933 _igvn.register_new_node_with_optimizer(new_head);
3934 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3935 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3936 set_loop(new_head, loop);
3937 loop->_body.push(new_head);
3938 not_peel.set(new_head->_idx);
3939 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3940 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3941
3942 while (sink_list.size() > 0) {
3943 Node* n = sink_list.pop();
3944 set_ctrl(n, new_head);
3945 }
3946
3947 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3948
3949 clone_loop(loop, old_new, dd, IgnoreStripMined);
3950
3951 const uint clone_exit_idx = 1;
3952 const uint orig_exit_idx = 2;
3953 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop");
3954
3955 Node* head_clone = old_new[head->_idx];
3956 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3957 Node* orig_tail_clone = head_clone->in(2);
3958
3959 // Add phi if "def" node is in peel set and "use" is not
3960
3961 for (uint i = 0; i < peel_list.size(); i++) {
3962 Node *def = peel_list.at(i);
3963 if (!def->is_CFG()) {
3964 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3965 Node *use = def->fast_out(j);
3966 if (has_node(use) && use->in(0) != C->top() &&
3967 (!peel.test(use->_idx) ||
3968 (use->is_Phi() && use->in(0) == head)) ) {
3969 worklist.push(use);
3970 }
3971 }
3972 while( worklist.size() ) {
3973 Node *use = worklist.pop();
3974 for (uint j = 1; j < use->req(); j++) {
3975 Node* n = use->in(j);
3976 if (n == def) {
3977
3978 // "def" is in peel set, "use" is not in peel set
3979 // or "use" is in the entry boundary (a phi) of the peel set
3980
3981 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3982
3983 if ( loop->is_member(get_loop( use_c )) ) {
3984 // use is in loop
3985 if (old_new[use->_idx] != nullptr) { // null for dead code
3986 Node* use_clone = old_new[use->_idx];
3987 _igvn.replace_input_of(use, j, C->top());
3988 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3989 }
3990 } else {
3991 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3992 // use is not in the loop, check if the live range includes the cut
3993 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3994 if (not_peel.test(lp_if->_idx)) {
3995 assert(j == orig_exit_idx, "use from original loop");
3996 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3997 }
3998 }
3999 }
4000 }
4001 }
4002 }
4003 }
4004
4005 // Step 3b: retarget control
4006
4007 // Redirect control to the new loop head if a cloned node in
4008 // the not_peeled region has control that points into the peeled region.
4009 // This necessary because the cloned peeled region will be outside
4010 // the loop.
4011 // from to
4012 // cloned-peeled <---+
4013 // new_head_clone: | <--+
4014 // cloned-not_peeled in(0) in(0)
4015 // orig-peeled
4016
4017 for (uint i = 0; i < loop->_body.size(); i++) {
4018 Node *n = loop->_body.at(i);
4019 if (!n->is_CFG() && n->in(0) != nullptr &&
4020 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
4021 Node* n_clone = old_new[n->_idx];
4022 _igvn.replace_input_of(n_clone, 0, new_head_clone);
4023 }
4024 }
4025
4026 // Backedge of the surviving new_head (the clone) is original last_peel
4027 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
4028
4029 // Cut first node in original not_peel set
4030 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
4031 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
4032 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
4033
4034 // Copy head_clone back-branch info to original head
4035 // and remove original head's loop entry and
4036 // clone head's back-branch
4037 _igvn.rehash_node_delayed(head); // Multiple edge updates
4038 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
4039 head->set_req(LoopNode::LoopBackControl, C->top());
4040 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
4041
4042 // Similarly modify the phis
4043 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
4044 Node* use = head->fast_out(k);
4045 if (use->is_Phi() && use->outcnt() > 0) {
4046 Node* use_clone = old_new[use->_idx];
4047 _igvn.rehash_node_delayed(use); // Multiple edge updates
4048 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
4049 use->set_req(LoopNode::LoopBackControl, C->top());
4050 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
4051 }
4052 }
4053
4054 // Step 4: update dominator tree and dominator depth
4055
4056 set_idom(head, orig_tail_clone, dd);
4057 recompute_dom_depth();
4058
4059 // Inhibit more partial peeling on this loop
4060 new_head_clone->set_partial_peel_loop();
4061 C->set_major_progress();
4062 loop->record_for_igvn();
4063
4064 #ifndef PRODUCT
4065 if (TracePartialPeeling) {
4066 tty->print_cr("\nafter partial peel one iteration");
4067 Node_List wl;
4068 Node* t = last_peel;
4069 while (true) {
4070 wl.push(t);
4071 if (t == head_clone) break;
4072 t = idom(t);
4073 }
4074 while (wl.size() > 0) {
4075 Node* tt = wl.pop();
4076 if (tt == head) tty->print_cr("orig head");
4077 else if (tt == new_head_clone) tty->print_cr("new head");
4078 else if (tt == head_clone) tty->print_cr("clone head");
4079 tt->dump();
4080 }
4081 }
4082 #endif
4083 return true;
4084 }
4085
4086 // Transform:
4087 //
4088 // loop<-----------------+
4089 // | |
4090 // stmt1 stmt2 .. stmtn |
4091 // | | | |
4092 // \ | / |
4093 // v v v |
4094 // region |
4095 // | |
4096 // shared_stmt |
4097 // | |
4098 // v |
4099 // if |
4100 // / \ |
4101 // | -----------+
4102 // v
4103 //
4104 // into:
4105 //
4106 // loop<-------------------+
4107 // | |
4108 // v |
4109 // +->loop |
4110 // | | |
4111 // | stmt1 stmt2 .. stmtn |
4112 // | | | | |
4113 // | | \ / |
4114 // | | v v |
4115 // | | region1 |
4116 // | | | |
4117 // | shared_stmt shared_stmt |
4118 // | | | |
4119 // | v v |
4120 // | if if |
4121 // | /\ / \ |
4122 // +-- | | -------+
4123 // \ /
4124 // v v
4125 // region2
4126 //
4127 // (region2 is shown to merge mirrored projections of the loop exit
4128 // ifs to make the diagram clearer but they really merge the same
4129 // projection)
4130 //
4131 // Conditions for this transformation to trigger:
4132 // - the path through stmt1 is frequent enough
4133 // - the inner loop will be turned into a counted loop after transformation
4134 bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new) {
4135 if (!DuplicateBackedge) {
4136 return false;
4137 }
4138 assert(!loop->_head->is_CountedLoop() || StressDuplicateBackedge, "Non-counted loop only");
4139 if (!loop->_head->is_Loop()) {
4140 return false;
4141 }
4142
4143 uint estimate = loop->est_loop_clone_sz(1);
4144 if (exceeding_node_budget(estimate)) {
4145 return false;
4146 }
4147
4148 LoopNode *head = loop->_head->as_Loop();
4149
4150 Node* region = nullptr;
4151 IfNode* exit_test = nullptr;
4152 uint inner;
4153 float f;
4154 if (StressDuplicateBackedge) {
4155 if (head->is_strip_mined()) {
4156 return false;
4157 }
4158 Node* c = head->in(LoopNode::LoopBackControl);
4159
4160 while (c != head) {
4161 if (c->is_Region()) {
4162 region = c;
4163 }
4164 c = idom(c);
4165 }
4166
4167 if (region == nullptr) {
4168 return false;
4169 }
4170
4171 inner = 1;
4172 } else {
4173 // Is the shape of the loop that of a counted loop...
4174 Node* back_control = loop_exit_control(head, loop);
4175 if (back_control == nullptr) {
4176 return false;
4177 }
4178
4179 BoolTest::mask bt = BoolTest::illegal;
4180 float cl_prob = 0;
4181 Node* incr = nullptr;
4182 Node* limit = nullptr;
4183 Node* cmp = loop_exit_test(back_control, loop, incr, limit, bt, cl_prob);
4184 if (cmp == nullptr || cmp->Opcode() != Op_CmpI) {
4185 return false;
4186 }
4187
4188 // With an extra phi for the candidate iv?
4189 // Or the region node is the loop head
4190 if (!incr->is_Phi() || incr->in(0) == head) {
4191 return false;
4192 }
4193
4194 PathFrequency pf(head, this);
4195 region = incr->in(0);
4196
4197 // Go over all paths for the extra phi's region and see if that
4198 // path is frequent enough and would match the expected iv shape
4199 // if the extra phi is removed
4200 inner = 0;
4201 for (uint i = 1; i < incr->req(); ++i) {
4202 Node* in = incr->in(i);
4203 Node* trunc1 = nullptr;
4204 Node* trunc2 = nullptr;
4205 const TypeInteger* iv_trunc_t = nullptr;
4206 Node* orig_in = in;
4207 if (!(in = CountedLoopNode::match_incr_with_optional_truncation(in, &trunc1, &trunc2, &iv_trunc_t, T_INT))) {
4208 continue;
4209 }
4210 assert(in->Opcode() == Op_AddI, "wrong increment code");
4211 Node* xphi = nullptr;
4212 Node* stride = loop_iv_stride(in, loop, xphi);
4213
4214 if (stride == nullptr) {
4215 continue;
4216 }
4217
4218 PhiNode* phi = loop_iv_phi(xphi, nullptr, head, loop);
4219 if (phi == nullptr ||
4220 (trunc1 == nullptr && phi->in(LoopNode::LoopBackControl) != incr) ||
4221 (trunc1 != nullptr && phi->in(LoopNode::LoopBackControl) != trunc1)) {
4222 return false;
4223 }
4224
4225 f = pf.to(region->in(i));
4226 if (f > 0.5) {
4227 inner = i;
4228 break;
4229 }
4230 }
4231
4232 if (inner == 0) {
4233 return false;
4234 }
4235
4236 exit_test = back_control->in(0)->as_If();
4237 }
4238
4239 if (idom(region)->is_Catch()) {
4240 return false;
4241 }
4242
4243 // Collect all control nodes that need to be cloned (shared_stmt in the diagram)
4244 Unique_Node_List wq;
4245 wq.push(head->in(LoopNode::LoopBackControl));
4246 for (uint i = 0; i < wq.size(); i++) {
4247 Node* c = wq.at(i);
4248 assert(get_loop(c) == loop, "not in the right loop?");
4249 if (c->is_Region()) {
4250 if (c != region) {
4251 for (uint j = 1; j < c->req(); ++j) {
4252 wq.push(c->in(j));
4253 }
4254 }
4255 } else {
4256 wq.push(c->in(0));
4257 }
4258 assert(!is_dominator(c, region) || c == region, "shouldn't go above region");
4259 }
4260
4261 Node* region_dom = idom(region);
4262
4263 // Can't do the transformation if this would cause a membar pair to
4264 // be split
4265 for (uint i = 0; i < wq.size(); i++) {
4266 Node* c = wq.at(i);
4267 if (c->is_MemBar() && (c->as_MemBar()->trailing_store() || c->as_MemBar()->trailing_load_store())) {
4268 assert(c->as_MemBar()->leading_membar()->trailing_membar() == c, "bad membar pair");
4269 if (!wq.member(c->as_MemBar()->leading_membar())) {
4270 return false;
4271 }
4272 }
4273 }
4274
4275 // Collect data nodes that need to be clones as well
4276 int dd = dom_depth(head);
4277
4278 for (uint i = 0; i < loop->_body.size(); ++i) {
4279 Node* n = loop->_body.at(i);
4280 if (has_ctrl(n)) {
4281 Node* c = get_ctrl(n);
4282 if (wq.member(c)) {
4283 wq.push(n);
4284 }
4285 } else {
4286 set_idom(n, idom(n), dd);
4287 }
4288 }
4289
4290 // clone shared_stmt
4291 clone_loop_body(wq, old_new, nullptr);
4292
4293 Node* region_clone = old_new[region->_idx];
4294 region_clone->set_req(inner, C->top());
4295 set_idom(region, region->in(inner), dd);
4296
4297 // Prepare the outer loop
4298 Node* outer_head = new LoopNode(head->in(LoopNode::EntryControl), old_new[head->in(LoopNode::LoopBackControl)->_idx]);
4299 register_control(outer_head, loop->_parent, outer_head->in(LoopNode::EntryControl));
4300 _igvn.replace_input_of(head, LoopNode::EntryControl, outer_head);
4301 set_idom(head, outer_head, dd);
4302
4303 fix_body_edges(wq, loop, old_new, dd, loop->_parent, true);
4304
4305 // Make one of the shared_stmt copies only reachable from stmt1, the
4306 // other only from stmt2..stmtn.
4307 Node* dom = nullptr;
4308 for (uint i = 1; i < region->req(); ++i) {
4309 if (i != inner) {
4310 _igvn.replace_input_of(region, i, C->top());
4311 }
4312 Node* in = region_clone->in(i);
4313 if (in->is_top()) {
4314 continue;
4315 }
4316 if (dom == nullptr) {
4317 dom = in;
4318 } else {
4319 dom = dom_lca(dom, in);
4320 }
4321 }
4322
4323 set_idom(region_clone, dom, dd);
4324
4325 // Set up the outer loop
4326 for (uint i = 0; i < head->outcnt(); i++) {
4327 Node* u = head->raw_out(i);
4328 if (u->is_Phi()) {
4329 Node* outer_phi = u->clone();
4330 outer_phi->set_req(0, outer_head);
4331 Node* backedge = old_new[u->in(LoopNode::LoopBackControl)->_idx];
4332 if (backedge == nullptr) {
4333 backedge = u->in(LoopNode::LoopBackControl);
4334 }
4335 outer_phi->set_req(LoopNode::LoopBackControl, backedge);
4336 register_new_node(outer_phi, outer_head);
4337 _igvn.replace_input_of(u, LoopNode::EntryControl, outer_phi);
4338 }
4339 }
4340
4341 // create control and data nodes for out of loop uses (including region2)
4342 Node_List worklist;
4343 uint new_counter = C->unique();
4344 fix_ctrl_uses(wq, loop, old_new, ControlAroundStripMined, outer_head, nullptr, worklist);
4345
4346 Node_List *split_if_set = nullptr;
4347 Node_List *split_bool_set = nullptr;
4348 Node_List *split_cex_set = nullptr;
4349 fix_data_uses(wq, loop, ControlAroundStripMined, head->is_strip_mined() ? loop->_parent : loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
4350
4351 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
4352
4353 if (exit_test != nullptr) {
4354 float cnt = exit_test->_fcnt;
4355 if (cnt != COUNT_UNKNOWN) {
4356 exit_test->_fcnt = cnt * f;
4357 old_new[exit_test->_idx]->as_If()->_fcnt = cnt * (1 - f);
4358 }
4359 }
4360
4361 C->set_major_progress();
4362
4363 return true;
4364 }
4365
4366 // Having ReductionNodes in the loop is expensive. They need to recursively
4367 // fold together the vector values, for every vectorized loop iteration. If
4368 // we encounter the following pattern, we can vector accumulate the values
4369 // inside the loop, and only have a single UnorderedReduction after the loop.
4370 //
4371 // CountedLoop init
4372 // | |
4373 // +------+ | +-----------------------+
4374 // | | | |
4375 // PhiNode (s) |
4376 // | |
4377 // | Vector |
4378 // | | |
4379 // UnorderedReduction (first_ur) |
4380 // | |
4381 // ... Vector |
4382 // | | |
4383 // UnorderedReduction (last_ur) |
4384 // | |
4385 // +---------------------+
4386 //
4387 // We patch the graph to look like this:
4388 //
4389 // CountedLoop identity_vector
4390 // | |
4391 // +-------+ | +---------------+
4392 // | | | |
4393 // PhiNode (v) |
4394 // | |
4395 // | Vector |
4396 // | | |
4397 // VectorAccumulator |
4398 // | |
4399 // ... Vector |
4400 // | | |
4401 // init VectorAccumulator |
4402 // | | | |
4403 // UnorderedReduction +-----------+
4404 //
4405 // We turned the scalar (s) Phi into a vectorized one (v). In the loop, we
4406 // use vector_accumulators, which do the same reductions, but only element
4407 // wise. This is a single operation per vector_accumulator, rather than many
4408 // for a UnorderedReduction. We can then reduce the last vector_accumulator
4409 // after the loop, and also reduce the init value into it.
4410 // We can not do this with all reductions. Some reductions do not allow the
4411 // reordering of operations (for example float addition).
4412 void PhaseIdealLoop::move_unordered_reduction_out_of_loop(IdealLoopTree* loop) {
4413 assert(!C->major_progress() && loop->is_counted() && loop->is_innermost(), "sanity");
4414
4415 // Find all Phi nodes with UnorderedReduction on backedge.
4416 CountedLoopNode* cl = loop->_head->as_CountedLoop();
4417 for (DUIterator_Fast jmax, j = cl->fast_outs(jmax); j < jmax; j++) {
4418 Node* phi = cl->fast_out(j);
4419 // We have a phi with a single use, and a UnorderedReduction on the backedge.
4420 if (!phi->is_Phi() || phi->outcnt() != 1 || !phi->in(2)->is_UnorderedReduction()) {
4421 continue;
4422 }
4423
4424 UnorderedReductionNode* last_ur = phi->in(2)->as_UnorderedReduction();
4425
4426 // Determine types
4427 const TypeVect* vec_t = last_ur->vect_type();
4428 uint vector_length = vec_t->length();
4429 BasicType bt = vec_t->element_basic_type();
4430 const Type* bt_t = Type::get_const_basic_type(bt);
4431
4432 // Convert opcode from vector-reduction -> scalar -> normal-vector-op
4433 const int sopc = VectorNode::scalar_opcode(last_ur->Opcode(), bt);
4434 const int vopc = VectorNode::opcode(sopc, bt);
4435 if (!Matcher::match_rule_supported_vector(vopc, vector_length, bt)) {
4436 DEBUG_ONLY( last_ur->dump(); )
4437 assert(false, "do not have normal vector op for this reduction");
4438 continue; // not implemented -> fails
4439 }
4440
4441 // Traverse up the chain of UnorderedReductions, checking that it loops back to
4442 // the phi. Check that all UnorderedReductions only have a single use, except for
4443 // the last (last_ur), which only has phi as a use in the loop, and all other uses
4444 // are outside the loop.
4445 UnorderedReductionNode* current = last_ur;
4446 UnorderedReductionNode* first_ur = nullptr;
4447 while (true) {
4448 assert(current->is_UnorderedReduction(), "sanity");
4449
4450 // Expect no ctrl and a vector_input from within the loop.
4451 Node* ctrl = current->in(0);
4452 Node* vector_input = current->in(2);
4453 if (ctrl != nullptr || get_ctrl(vector_input) != cl) {
4454 DEBUG_ONLY( current->dump(1); )
4455 assert(false, "reduction has ctrl or bad vector_input");
4456 break; // Chain traversal fails.
4457 }
4458
4459 assert(current->vect_type() != nullptr, "must have vector type");
4460 if (current->vect_type() != last_ur->vect_type()) {
4461 // Reductions do not have the same vector type (length and element type).
4462 break; // Chain traversal fails.
4463 }
4464
4465 // Expect single use of UnorderedReduction, except for last_ur.
4466 if (current == last_ur) {
4467 // Expect all uses to be outside the loop, except phi.
4468 for (DUIterator_Fast kmax, k = current->fast_outs(kmax); k < kmax; k++) {
4469 Node* use = current->fast_out(k);
4470 if (use != phi && ctrl_or_self(use) == cl) {
4471 DEBUG_ONLY( current->dump(-1); )
4472 assert(false, "reduction has use inside loop");
4473 // Should not be allowed by SuperWord::mark_reductions
4474 return; // bail out of optimization
4475 }
4476 }
4477 } else {
4478 if (current->outcnt() != 1) {
4479 break; // Chain traversal fails.
4480 }
4481 }
4482
4483 // Expect another UnorderedReduction or phi as the scalar input.
4484 Node* scalar_input = current->in(1);
4485 if (scalar_input->is_UnorderedReduction() &&
4486 scalar_input->Opcode() == current->Opcode()) {
4487 // Move up the UnorderedReduction chain.
4488 current = scalar_input->as_UnorderedReduction();
4489 } else if (scalar_input == phi) {
4490 // Chain terminates at phi.
4491 first_ur = current;
4492 current = nullptr;
4493 break; // Success.
4494 } else {
4495 // scalar_input is neither phi nor a matching reduction
4496 // Can for example be scalar reduction when we have
4497 // partial vectorization.
4498 break; // Chain traversal fails.
4499 }
4500 }
4501 if (current != nullptr) {
4502 // Chain traversal was not successful.
4503 continue;
4504 }
4505 assert(first_ur != nullptr, "must have successfully terminated chain traversal");
4506
4507 Node* identity_scalar = ReductionNode::make_identity_con_scalar(_igvn, sopc, bt);
4508 set_ctrl(identity_scalar, C->root());
4509 VectorNode* identity_vector = VectorNode::scalar2vector(identity_scalar, vector_length, bt_t);
4510 register_new_node(identity_vector, C->root());
4511 assert(vec_t == identity_vector->vect_type(), "matching vector type");
4512 VectorNode::trace_new_vector(identity_vector, "UnorderedReduction");
4513
4514 // Turn the scalar phi into a vector phi.
4515 _igvn.rehash_node_delayed(phi);
4516 Node* init = phi->in(1); // Remember init before replacing it.
4517 phi->set_req_X(1, identity_vector, &_igvn);
4518 phi->as_Type()->set_type(vec_t);
4519 _igvn.set_type(phi, vec_t);
4520
4521 // Traverse down the chain of UnorderedReductions, and replace them with vector_accumulators.
4522 current = first_ur;
4523 while (true) {
4524 // Create vector_accumulator to replace current.
4525 Node* last_vector_accumulator = current->in(1);
4526 Node* vector_input = current->in(2);
4527 VectorNode* vector_accumulator = VectorNode::make(vopc, last_vector_accumulator, vector_input, vec_t);
4528 register_new_node(vector_accumulator, cl);
4529 _igvn.replace_node(current, vector_accumulator);
4530 VectorNode::trace_new_vector(vector_accumulator, "UnorderedReduction");
4531 if (current == last_ur) {
4532 break;
4533 }
4534 current = vector_accumulator->unique_out()->as_UnorderedReduction();
4535 }
4536
4537 // Create post-loop reduction.
4538 Node* last_accumulator = phi->in(2);
4539 Node* post_loop_reduction = ReductionNode::make(sopc, nullptr, init, last_accumulator, bt);
4540
4541 // Take over uses of last_accumulator that are not in the loop.
4542 for (DUIterator i = last_accumulator->outs(); last_accumulator->has_out(i); i++) {
4543 Node* use = last_accumulator->out(i);
4544 if (use != phi && use != post_loop_reduction) {
4545 assert(ctrl_or_self(use) != cl, "use must be outside loop");
4546 use->replace_edge(last_accumulator, post_loop_reduction, &_igvn);
4547 --i;
4548 }
4549 }
4550 register_new_node(post_loop_reduction, get_late_ctrl(post_loop_reduction, cl));
4551 VectorNode::trace_new_vector(post_loop_reduction, "UnorderedReduction");
4552
4553 assert(last_accumulator->outcnt() == 2, "last_accumulator has 2 uses: phi and post_loop_reduction");
4554 assert(post_loop_reduction->outcnt() > 0, "should have taken over all non loop uses of last_accumulator");
4555 assert(phi->outcnt() == 1, "accumulator is the only use of phi");
4556 }
4557 }