1 /*
2 * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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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/loopnode.hpp"
37 #include "opto/matcher.hpp"
38 #include "opto/mulnode.hpp"
39 #include "opto/movenode.hpp"
40 #include "opto/opaquenode.hpp"
41 #include "opto/rootnode.hpp"
42 #include "opto/subnode.hpp"
43 #include "opto/subtypenode.hpp"
44 #include "utilities/macros.hpp"
45
46 //=============================================================================
47 //------------------------------split_thru_phi---------------------------------
48 // Split Node 'n' through merge point if there is enough win.
49 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) {
50 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
51 // ConvI2L may have type information on it which is unsafe to push up
52 // so disable this for now
53 return NULL;
54 }
55
56 // Splitting range check CastIIs through a loop induction Phi can
57 // cause new Phis to be created that are left unrelated to the loop
58 // induction Phi and prevent optimizations (vectorization)
59 if (n->Opcode() == Op_CastII && region->is_CountedLoop() &&
60 n->in(1) == region->as_CountedLoop()->phi()) {
61 return NULL;
62 }
63
64 if (cannot_split_division(n, region)) {
65 return NULL;
66 }
67
68 int wins = 0;
69 assert(!n->is_CFG(), "");
70 assert(region->is_Region(), "");
71
72 const Type* type = n->bottom_type();
73 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr();
74 Node* phi;
75 if (t_oop != NULL && t_oop->is_known_instance_field()) {
76 int iid = t_oop->instance_id();
77 int index = C->get_alias_index(t_oop);
78 int offset = t_oop->offset();
79 phi = new PhiNode(region, type, NULL, iid, index, offset);
80 } else {
81 phi = PhiNode::make_blank(region, n);
82 }
83 uint old_unique = C->unique();
84 for (uint i = 1; i < region->req(); i++) {
85 Node* x;
86 Node* the_clone = NULL;
87 if (region->in(i) == C->top()) {
88 x = C->top(); // Dead path? Use a dead data op
89 } else {
90 x = n->clone(); // Else clone up the data op
91 the_clone = x; // Remember for possible deletion.
92 // Alter data node to use pre-phi inputs
93 if (n->in(0) == region)
94 x->set_req( 0, region->in(i) );
95 for (uint j = 1; j < n->req(); j++) {
96 Node* in = n->in(j);
97 if (in->is_Phi() && in->in(0) == region)
98 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
99 }
100 }
101 // Check for a 'win' on some paths
102 const Type* t = x->Value(&_igvn);
103
104 bool singleton = t->singleton();
105
106 // A TOP singleton indicates that there are no possible values incoming
107 // along a particular edge. In most cases, this is OK, and the Phi will
108 // be eliminated later in an Ideal call. However, we can't allow this to
109 // happen if the singleton occurs on loop entry, as the elimination of
110 // the PhiNode may cause the resulting node to migrate back to a previous
111 // loop iteration.
112 if (singleton && t == Type::TOP) {
113 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
114 // irreducible loop may not be indicated by an affirmative is_Loop());
115 // therefore, the only top we can split thru a phi is on a backedge of
116 // a loop.
117 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
118 }
119
120 if (singleton) {
121 wins++;
122 x = ((PhaseGVN&)_igvn).makecon(t);
123 } else {
124 // We now call Identity to try to simplify the cloned node.
125 // Note that some Identity methods call phase->type(this).
126 // Make sure that the type array is big enough for
127 // our new node, even though we may throw the node away.
128 // (Note: This tweaking with igvn only works because x is a new node.)
129 _igvn.set_type(x, t);
130 // If x is a TypeNode, capture any more-precise type permanently into Node
131 // otherwise it will be not updated during igvn->transform since
132 // igvn->type(x) is set to x->Value() already.
133 x->raise_bottom_type(t);
134 Node* y = x->Identity(&_igvn);
135 if (y != x) {
136 wins++;
137 x = y;
138 } else {
139 y = _igvn.hash_find(x);
140 if (y) {
141 wins++;
142 x = y;
143 } else {
144 // Else x is a new node we are keeping
145 // We do not need register_new_node_with_optimizer
146 // because set_type has already been called.
147 _igvn._worklist.push(x);
148 }
149 }
150 }
151 if (x != the_clone && the_clone != NULL)
152 _igvn.remove_dead_node(the_clone);
153 phi->set_req( i, x );
154 }
155 // Too few wins?
156 if (wins <= policy) {
157 _igvn.remove_dead_node(phi);
158 return NULL;
159 }
160
161 // Record Phi
162 register_new_node( phi, region );
163
164 for (uint i2 = 1; i2 < phi->req(); i2++) {
165 Node *x = phi->in(i2);
166 // If we commoned up the cloned 'x' with another existing Node,
167 // the existing Node picks up a new use. We need to make the
168 // existing Node occur higher up so it dominates its uses.
169 Node *old_ctrl;
170 IdealLoopTree *old_loop;
171
172 if (x->is_Con()) {
173 // Constant's control is always root.
174 set_ctrl(x, C->root());
175 continue;
176 }
177 // The occasional new node
178 if (x->_idx >= old_unique) { // Found a new, unplaced node?
179 old_ctrl = NULL;
180 old_loop = NULL; // Not in any prior loop
181 } else {
182 old_ctrl = get_ctrl(x);
183 old_loop = get_loop(old_ctrl); // Get prior loop
184 }
185 // New late point must dominate new use
186 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
187 if (new_ctrl == old_ctrl) // Nothing is changed
188 continue;
189
190 IdealLoopTree *new_loop = get_loop(new_ctrl);
191
192 // Don't move x into a loop if its uses are
193 // outside of loop. Otherwise x will be cloned
194 // for each use outside of this loop.
195 IdealLoopTree *use_loop = get_loop(region);
196 if (!new_loop->is_member(use_loop) &&
197 (old_loop == NULL || !new_loop->is_member(old_loop))) {
198 // Take early control, later control will be recalculated
199 // during next iteration of loop optimizations.
200 new_ctrl = get_early_ctrl(x);
201 new_loop = get_loop(new_ctrl);
202 }
203 // Set new location
204 set_ctrl(x, new_ctrl);
205 // If changing loop bodies, see if we need to collect into new body
206 if (old_loop != new_loop) {
207 if (old_loop && !old_loop->_child)
208 old_loop->_body.yank(x);
209 if (!new_loop->_child)
210 new_loop->_body.push(x); // Collect body info
211 }
212 }
213
214 return phi;
215 }
216
217 // Return true if 'n' is a Div or Mod node (without zero check If node which was removed earlier) with a loop phi divisor
218 // of a trip-counted (integer or long) loop with a backedge input that could be zero (include zero in its type range). In
219 // this case, we cannot split the division to the backedge as it could freely float above the loop exit check resulting in
220 // a division by zero. This situation is possible because the type of an increment node of an iv phi (trip-counter) could
221 // include zero while the iv phi does not (see PhiNode::Value() for trip-counted loops where we improve types of iv phis).
222 // We also need to check other loop phis as they could have been created in the same split-if pass when applying
223 // PhaseIdealLoop::split_thru_phi() to split nodes through an iv phi.
224 bool PhaseIdealLoop::cannot_split_division(const Node* n, const Node* region) const {
225 const Type* zero;
226 switch (n->Opcode()) {
227 case Op_DivI:
228 case Op_ModI:
229 zero = TypeInt::ZERO;
230 break;
231 case Op_DivL:
232 case Op_ModL:
233 zero = TypeLong::ZERO;
234 break;
235 default:
236 return false;
237 }
238
239 assert(n->in(0) == NULL, "divisions with zero check should already have bailed out earlier in split-if");
240 Node* divisor = n->in(2);
241 return is_divisor_counted_loop_phi(divisor, region) &&
242 loop_phi_backedge_type_contains_zero(divisor, zero);
243 }
244
245 bool PhaseIdealLoop::is_divisor_counted_loop_phi(const Node* divisor, const Node* loop) {
246 return loop->is_BaseCountedLoop() && divisor->is_Phi() && divisor->in(0) == loop;
247 }
248
249 bool PhaseIdealLoop::loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const {
250 return _igvn.type(phi_divisor->in(LoopNode::LoopBackControl))->filter_speculative(zero) != Type::TOP;
251 }
252
253 //------------------------------dominated_by------------------------------------
254 // Replace the dominated test with an obvious true or false. Place it on the
255 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
256 // live path up to the dominating control.
257 void PhaseIdealLoop::dominated_by(IfProjNode* prevdom, IfNode* iff, bool flip, bool exclude_loop_predicate) {
258 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
259
260 // prevdom is the dominating projection of the dominating test.
261 assert(iff->Opcode() == Op_If ||
262 iff->Opcode() == Op_CountedLoopEnd ||
263 iff->Opcode() == Op_LongCountedLoopEnd ||
264 iff->Opcode() == Op_RangeCheck,
265 "Check this code when new subtype is added");
266
267 int pop = prevdom->Opcode();
268 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
269 if (flip) {
270 if (pop == Op_IfTrue)
271 pop = Op_IfFalse;
272 else
273 pop = Op_IfTrue;
274 }
275 // 'con' is set to true or false to kill the dominated test.
276 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
277 set_ctrl(con, C->root()); // Constant gets a new use
278 // Hack the dominated test
279 _igvn.replace_input_of(iff, 1, con);
280
281 // If I dont have a reachable TRUE and FALSE path following the IfNode then
282 // I can assume this path reaches an infinite loop. In this case it's not
283 // important to optimize the data Nodes - either the whole compilation will
284 // be tossed or this path (and all data Nodes) will go dead.
285 if (iff->outcnt() != 2) return;
286
287 // Make control-dependent data Nodes on the live path (path that will remain
288 // once the dominated IF is removed) become control-dependent on the
289 // dominating projection.
290 Node* dp = iff->proj_out_or_null(pop == Op_IfTrue);
291
292 // Loop predicates may have depending checks which should not
293 // be skipped. For example, range check predicate has two checks
294 // for lower and upper bounds.
295 if (dp == NULL)
296 return;
297
298 ProjNode* dp_proj = dp->as_Proj();
299 ProjNode* unc_proj = iff->proj_out(1 - dp_proj->_con)->as_Proj();
300 if (exclude_loop_predicate &&
301 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL ||
302 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_profile_predicate) != NULL ||
303 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) {
304 // If this is a range check (IfNode::is_range_check), do not
305 // reorder because Compile::allow_range_check_smearing might have
306 // changed the check.
307 return; // Let IGVN transformation change control dependence.
308 }
309
310 IdealLoopTree* old_loop = get_loop(dp);
311
312 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
313 Node* cd = dp->fast_out(i); // Control-dependent node
314 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check.
315 if (cd->depends_only_on_test() && _igvn.no_dependent_zero_check(cd)) {
316 assert(cd->in(0) == dp, "");
317 _igvn.replace_input_of(cd, 0, prevdom);
318 set_early_ctrl(cd, false);
319 IdealLoopTree* new_loop = get_loop(get_ctrl(cd));
320 if (old_loop != new_loop) {
321 if (!old_loop->_child) {
322 old_loop->_body.yank(cd);
323 }
324 if (!new_loop->_child) {
325 new_loop->_body.push(cd);
326 }
327 }
328 --i;
329 --imax;
330 }
331 }
332 }
333
334 //------------------------------has_local_phi_input----------------------------
335 // Return TRUE if 'n' has Phi inputs from its local block and no other
336 // block-local inputs (all non-local-phi inputs come from earlier blocks)
337 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
338 Node *n_ctrl = get_ctrl(n);
339 // See if some inputs come from a Phi in this block, or from before
340 // this block.
341 uint i;
342 for( i = 1; i < n->req(); i++ ) {
343 Node *phi = n->in(i);
344 if( phi->is_Phi() && phi->in(0) == n_ctrl )
345 break;
346 }
347 if( i >= n->req() )
348 return NULL; // No Phi inputs; nowhere to clone thru
349
350 // Check for inputs created between 'n' and the Phi input. These
351 // must split as well; they have already been given the chance
352 // (courtesy of a post-order visit) and since they did not we must
353 // recover the 'cost' of splitting them by being very profitable
354 // when splitting 'n'. Since this is unlikely we simply give up.
355 for( i = 1; i < n->req(); i++ ) {
356 Node *m = n->in(i);
357 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
358 // We allow the special case of AddP's with no local inputs.
359 // This allows us to split-up address expressions.
360 if (m->is_AddP() &&
361 get_ctrl(m->in(AddPNode::Base)) != n_ctrl &&
362 get_ctrl(m->in(AddPNode::Address)) != n_ctrl &&
363 get_ctrl(m->in(AddPNode::Offset)) != n_ctrl) {
364 // Move the AddP up to the dominating point. That's fine because control of m's inputs
365 // must dominate get_ctrl(m) == n_ctrl and we just checked that the input controls are != n_ctrl.
366 Node* c = find_non_split_ctrl(idom(n_ctrl));
367 if (c->is_OuterStripMinedLoop()) {
368 c->as_Loop()->verify_strip_mined(1);
369 c = c->in(LoopNode::EntryControl);
370 }
371 set_ctrl_and_loop(m, c);
372 continue;
373 }
374 return NULL;
375 }
376 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
377 }
378
379 return n_ctrl;
380 }
381
382 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
383 Node* PhaseIdealLoop::remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt) {
384 assert(bt == T_INT || bt == T_LONG, "only for integers");
385 int n_op = n->Opcode();
386
387 if (n_op == Op_LShift(bt)) {
388 // Scale is loop invariant
389 Node* scale = n->in(2);
390 Node* scale_ctrl = get_ctrl(scale);
391 IdealLoopTree* scale_loop = get_loop(scale_ctrl);
392 if (n_loop == scale_loop || !scale_loop->is_member(n_loop)) {
393 return NULL;
394 }
395 const TypeInt* scale_t = scale->bottom_type()->isa_int();
396 if (scale_t != NULL && scale_t->is_con() && scale_t->get_con() >= 16) {
397 return NULL; // Dont bother with byte/short masking
398 }
399 // Add must vary with loop (else shift would be loop-invariant)
400 Node* add = n->in(1);
401 Node* add_ctrl = get_ctrl(add);
402 IdealLoopTree* add_loop = get_loop(add_ctrl);
403 if (n_loop != add_loop) {
404 return NULL; // happens w/ evil ZKM loops
405 }
406
407 // Convert I-V into I+ (0-V); same for V-I
408 if (add->Opcode() == Op_Sub(bt) &&
409 _igvn.type(add->in(1)) != TypeInteger::zero(bt)) {
410 assert(add->Opcode() == Op_SubI || add->Opcode() == Op_SubL, "");
411 Node* zero = _igvn.integercon(0, bt);
412 set_ctrl(zero, C->root());
413 Node* neg = SubNode::make(zero, add->in(2), bt);
414 register_new_node(neg, get_ctrl(add->in(2)));
415 add = AddNode::make(add->in(1), neg, bt);
416 register_new_node(add, add_ctrl);
417 }
418 if (add->Opcode() != Op_Add(bt)) return NULL;
419 assert(add->Opcode() == Op_AddI || add->Opcode() == Op_AddL, "");
420 // See if one add input is loop invariant
421 Node* add_var = add->in(1);
422 Node* add_var_ctrl = get_ctrl(add_var);
423 IdealLoopTree* add_var_loop = get_loop(add_var_ctrl);
424 Node* add_invar = add->in(2);
425 Node* add_invar_ctrl = get_ctrl(add_invar);
426 IdealLoopTree* add_invar_loop = get_loop(add_invar_ctrl);
427 if (add_invar_loop == n_loop) {
428 // Swap to find the invariant part
429 add_invar = add_var;
430 add_invar_ctrl = add_var_ctrl;
431 add_invar_loop = add_var_loop;
432 add_var = add->in(2);
433 } else if (add_var_loop != n_loop) { // Else neither input is loop invariant
434 return NULL;
435 }
436 if (n_loop == add_invar_loop || !add_invar_loop->is_member(n_loop)) {
437 return NULL; // No invariant part of the add?
438 }
439
440 // Yes! Reshape address expression!
441 Node* inv_scale = LShiftNode::make(add_invar, scale, bt);
442 Node* inv_scale_ctrl =
443 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
444 add_invar_ctrl : scale_ctrl;
445 register_new_node(inv_scale, inv_scale_ctrl);
446 Node* var_scale = LShiftNode::make(add_var, scale, bt);
447 register_new_node(var_scale, n_ctrl);
448 Node* var_add = AddNode::make(var_scale, inv_scale, bt);
449 register_new_node(var_add, n_ctrl);
450 _igvn.replace_node(n, var_add);
451 return var_add;
452 }
453 return NULL;
454 }
455
456 //------------------------------remix_address_expressions----------------------
457 // Rework addressing expressions to get the most loop-invariant stuff
458 // moved out. We'd like to do all associative operators, but it's especially
459 // important (common) to do address expressions.
460 Node* PhaseIdealLoop::remix_address_expressions(Node* n) {
461 if (!has_ctrl(n)) return NULL;
462 Node* n_ctrl = get_ctrl(n);
463 IdealLoopTree* n_loop = get_loop(n_ctrl);
464
465 // See if 'n' mixes loop-varying and loop-invariant inputs and
466 // itself is loop-varying.
467
468 // Only interested in binary ops (and AddP)
469 if (n->req() < 3 || n->req() > 4) return NULL;
470
471 Node* n1_ctrl = get_ctrl(n->in( 1));
472 Node* n2_ctrl = get_ctrl(n->in( 2));
473 Node* n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
474 IdealLoopTree* n1_loop = get_loop(n1_ctrl);
475 IdealLoopTree* n2_loop = get_loop(n2_ctrl);
476 IdealLoopTree* n3_loop = get_loop(n3_ctrl);
477
478 // Does one of my inputs spin in a tighter loop than self?
479 if ((n_loop->is_member(n1_loop) && n_loop != n1_loop) ||
480 (n_loop->is_member(n2_loop) && n_loop != n2_loop) ||
481 (n_loop->is_member(n3_loop) && n_loop != n3_loop)) {
482 return NULL; // Leave well enough alone
483 }
484
485 // Is at least one of my inputs loop-invariant?
486 if (n1_loop == n_loop &&
487 n2_loop == n_loop &&
488 n3_loop == n_loop) {
489 return NULL; // No loop-invariant inputs
490 }
491
492 Node* res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_INT);
493 if (res != NULL) {
494 return res;
495 }
496 res = remix_address_expressions_add_left_shift(n, n_loop, n_ctrl, T_LONG);
497 if (res != NULL) {
498 return res;
499 }
500
501 int n_op = n->Opcode();
502 // Replace (I+V) with (V+I)
503 if (n_op == Op_AddI ||
504 n_op == Op_AddL ||
505 n_op == Op_AddF ||
506 n_op == Op_AddD ||
507 n_op == Op_MulI ||
508 n_op == Op_MulL ||
509 n_op == Op_MulF ||
510 n_op == Op_MulD) {
511 if (n2_loop == n_loop) {
512 assert(n1_loop != n_loop, "");
513 n->swap_edges(1, 2);
514 }
515 }
516
517 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
518 // but not if I2 is a constant.
519 if (n_op == Op_AddP) {
520 if (n2_loop == n_loop && n3_loop != n_loop) {
521 if (n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con()) {
522 Node* n22_ctrl = get_ctrl(n->in(2)->in(2));
523 Node* n23_ctrl = get_ctrl(n->in(2)->in(3));
524 IdealLoopTree* n22loop = get_loop(n22_ctrl);
525 IdealLoopTree* n23_loop = get_loop(n23_ctrl);
526 if (n22loop != n_loop && n22loop->is_member(n_loop) &&
527 n23_loop == n_loop) {
528 Node* add1 = new AddPNode(n->in(1), n->in(2)->in(2), n->in(3));
529 // Stuff new AddP in the loop preheader
530 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl));
531 Node* add2 = new AddPNode(n->in(1), add1, n->in(2)->in(3));
532 register_new_node(add2, n_ctrl);
533 _igvn.replace_node(n, add2);
534 return add2;
535 }
536 }
537 }
538
539 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
540 if (n2_loop != n_loop && n3_loop == n_loop) {
541 if (n->in(3)->Opcode() == Op_AddX) {
542 Node* V = n->in(3)->in(1);
543 Node* I = n->in(3)->in(2);
544 if (is_member(n_loop,get_ctrl(V))) {
545 } else {
546 Node *tmp = V; V = I; I = tmp;
547 }
548 if (!is_member(n_loop,get_ctrl(I))) {
549 Node* add1 = new AddPNode(n->in(1), n->in(2), I);
550 // Stuff new AddP in the loop preheader
551 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl));
552 Node* add2 = new AddPNode(n->in(1), add1, V);
553 register_new_node(add2, n_ctrl);
554 _igvn.replace_node(n, add2);
555 return add2;
556 }
557 }
558 }
559 }
560
561 return NULL;
562 }
563
564 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1]))
565 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) {
566 assert(n->Opcode() == Op_AddI, "sanity");
567 Node * nn = NULL;
568 Node * in1 = n->in(1);
569 Node * in2 = n->in(2);
570 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) {
571 IdealLoopTree* loop_n = get_loop(get_ctrl(n));
572 if (loop_n->is_counted() &&
573 loop_n->_head->as_Loop()->is_valid_counted_loop(T_INT) &&
574 Matcher::match_rule_supported(Op_MulAddVS2VI) &&
575 Matcher::match_rule_supported(Op_MulAddS2I)) {
576 Node* mul_in1 = in1->in(1);
577 Node* mul_in2 = in1->in(2);
578 Node* mul_in3 = in2->in(1);
579 Node* mul_in4 = in2->in(2);
580 if (mul_in1->Opcode() == Op_LoadS &&
581 mul_in2->Opcode() == Op_LoadS &&
582 mul_in3->Opcode() == Op_LoadS &&
583 mul_in4->Opcode() == Op_LoadS) {
584 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1));
585 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2));
586 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3));
587 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4));
588 IdealLoopTree* loop5 = get_loop(get_ctrl(in1));
589 IdealLoopTree* loop6 = get_loop(get_ctrl(in2));
590 // All nodes should be in the same counted loop.
591 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 &&
592 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) {
593 Node* adr1 = mul_in1->in(MemNode::Address);
594 Node* adr2 = mul_in2->in(MemNode::Address);
595 Node* adr3 = mul_in3->in(MemNode::Address);
596 Node* adr4 = mul_in4->in(MemNode::Address);
597 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) {
598 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) &&
599 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) {
600 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4);
601 register_new_node(nn, get_ctrl(n));
602 _igvn.replace_node(n, nn);
603 return nn;
604 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) &&
605 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) {
606 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3);
607 register_new_node(nn, get_ctrl(n));
608 _igvn.replace_node(n, nn);
609 return nn;
610 }
611 }
612 }
613 }
614 }
615 }
616 return nn;
617 }
618
619 //------------------------------conditional_move-------------------------------
620 // Attempt to replace a Phi with a conditional move. We have some pretty
621 // strict profitability requirements. All Phis at the merge point must
622 // be converted, so we can remove the control flow. We need to limit the
623 // number of c-moves to a small handful. All code that was in the side-arms
624 // of the CFG diamond is now speculatively executed. This code has to be
625 // "cheap enough". We are pretty much limited to CFG diamonds that merge
626 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
627 Node *PhaseIdealLoop::conditional_move( Node *region ) {
628
629 assert(region->is_Region(), "sanity check");
630 if (region->req() != 3) return NULL;
631
632 // Check for CFG diamond
633 Node *lp = region->in(1);
634 Node *rp = region->in(2);
635 if (!lp || !rp) return NULL;
636 Node *lp_c = lp->in(0);
637 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL;
638 IfNode *iff = lp_c->as_If();
639
640 // Check for ops pinned in an arm of the diamond.
641 // Can't remove the control flow in this case
642 if (lp->outcnt() > 1) return NULL;
643 if (rp->outcnt() > 1) return NULL;
644
645 IdealLoopTree* r_loop = get_loop(region);
646 assert(r_loop == get_loop(iff), "sanity");
647 // Always convert to CMOVE if all results are used only outside this loop.
648 bool used_inside_loop = (r_loop == _ltree_root);
649
650 // Check profitability
651 int cost = 0;
652 int phis = 0;
653 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
654 Node *out = region->fast_out(i);
655 if (!out->is_Phi()) continue; // Ignore other control edges, etc
656 phis++;
657 PhiNode* phi = out->as_Phi();
658 BasicType bt = phi->type()->basic_type();
659 switch (bt) {
660 case T_DOUBLE:
661 case T_FLOAT:
662 if (C->use_cmove()) {
663 continue; //TODO: maybe we want to add some cost
664 }
665 cost += Matcher::float_cmove_cost(); // Could be very expensive
666 break;
667 case T_LONG: {
668 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
669 }
670 case T_INT: // These all CMOV fine
671 case T_ADDRESS: { // (RawPtr)
672 cost++;
673 break;
674 }
675 case T_NARROWOOP: // Fall through
676 case T_OBJECT: { // Base oops are OK, but not derived oops
677 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
678 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
679 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
680 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
681 // have a Phi for the base here that we convert to a CMOVE all is well
682 // and good. But if the base is dead, we'll not make a CMOVE. Later
683 // the allocator will have to produce a base by creating a CMOVE of the
684 // relevant bases. This puts the allocator in the business of
685 // manufacturing expensive instructions, generally a bad plan.
686 // Just Say No to Conditionally-Moved Derived Pointers.
687 if (tp && tp->offset() != 0)
688 return NULL;
689 cost++;
690 break;
691 }
692 default:
693 return NULL; // In particular, can't do memory or I/O
694 }
695 // Add in cost any speculative ops
696 for (uint j = 1; j < region->req(); j++) {
697 Node *proj = region->in(j);
698 Node *inp = phi->in(j);
699 if (get_ctrl(inp) == proj) { // Found local op
700 cost++;
701 // Check for a chain of dependent ops; these will all become
702 // speculative in a CMOV.
703 for (uint k = 1; k < inp->req(); k++)
704 if (get_ctrl(inp->in(k)) == proj)
705 cost += ConditionalMoveLimit; // Too much speculative goo
706 }
707 }
708 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
709 // This will likely Split-If, a higher-payoff operation.
710 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
711 Node* use = phi->fast_out(k);
712 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
713 cost += ConditionalMoveLimit;
714 // Is there a use inside the loop?
715 // Note: check only basic types since CMoveP is pinned.
716 if (!used_inside_loop && is_java_primitive(bt)) {
717 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
718 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
719 used_inside_loop = true;
720 }
721 }
722 }
723 }//for
724 Node* bol = iff->in(1);
725 if (bol->Opcode() == Op_Opaque4) {
726 return NULL; // Ignore loop predicate checks (the Opaque4 ensures they will go away)
727 }
728 assert(bol->Opcode() == Op_Bool, "Unexpected node");
729 int cmp_op = bol->in(1)->Opcode();
730 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode
731 return NULL;
732 }
733 // It is expensive to generate flags from a float compare.
734 // Avoid duplicated float compare.
735 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL;
736
737 float infrequent_prob = PROB_UNLIKELY_MAG(3);
738 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
739 if (used_inside_loop) {
740 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo
741
742 // BlockLayoutByFrequency optimization moves infrequent branch
743 // from hot path. No point in CMOV'ing in such case (110 is used
744 // instead of 100 to take into account not exactness of float value).
745 if (BlockLayoutByFrequency) {
746 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
747 }
748 }
749 // Check for highly predictable branch. No point in CMOV'ing if
750 // we are going to predict accurately all the time.
751 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
752 //keep going
753 } else if (iff->_prob < infrequent_prob ||
754 iff->_prob > (1.0f - infrequent_prob))
755 return NULL;
756
757 // --------------
758 // Now replace all Phis with CMOV's
759 Node *cmov_ctrl = iff->in(0);
760 uint flip = (lp->Opcode() == Op_IfTrue);
761 Node_List wq;
762 while (1) {
763 PhiNode* phi = NULL;
764 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
765 Node *out = region->fast_out(i);
766 if (out->is_Phi()) {
767 phi = out->as_Phi();
768 break;
769 }
770 }
771 if (phi == NULL || _igvn.type(phi) == Type::TOP) {
772 break;
773 }
774 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
775 // Move speculative ops
776 wq.push(phi);
777 while (wq.size() > 0) {
778 Node *n = wq.pop();
779 for (uint j = 1; j < n->req(); j++) {
780 Node* m = n->in(j);
781 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) {
782 #ifndef PRODUCT
783 if (PrintOpto && VerifyLoopOptimizations) {
784 tty->print(" speculate: ");
785 m->dump();
786 }
787 #endif
788 set_ctrl(m, cmov_ctrl);
789 wq.push(m);
790 }
791 }
792 }
793 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
794 register_new_node( cmov, cmov_ctrl );
795 _igvn.replace_node( phi, cmov );
796 #ifndef PRODUCT
797 if (TraceLoopOpts) {
798 tty->print("CMOV ");
799 r_loop->dump_head();
800 if (Verbose) {
801 bol->in(1)->dump(1);
802 cmov->dump(1);
803 }
804 }
805 if (VerifyLoopOptimizations) verify();
806 #endif
807 }
808
809 // The useless CFG diamond will fold up later; see the optimization in
810 // RegionNode::Ideal.
811 _igvn._worklist.push(region);
812
813 return iff->in(1);
814 }
815
816 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
817 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
818 Node* u = m->fast_out(i);
819 if (u->is_CFG()) {
820 if (u->is_NeverBranch()) {
821 u = u->as_NeverBranch()->proj_out(0);
822 enqueue_cfg_uses(u, wq);
823 } else {
824 wq.push(u);
825 }
826 }
827 }
828 }
829
830 // Try moving a store out of a loop, right before the loop
831 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
832 // Store has to be first in the loop body
833 IdealLoopTree *n_loop = get_loop(n_ctrl);
834 if (n->is_Store() && n_loop != _ltree_root &&
835 n_loop->is_loop() && n_loop->_head->is_Loop() &&
836 n->in(0) != NULL) {
837 Node* address = n->in(MemNode::Address);
838 Node* value = n->in(MemNode::ValueIn);
839 Node* mem = n->in(MemNode::Memory);
840 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
841 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
842
843 // - address and value must be loop invariant
844 // - memory must be a memory Phi for the loop
845 // - Store must be the only store on this memory slice in the
846 // loop: if there's another store following this one then value
847 // written at iteration i by the second store could be overwritten
848 // at iteration i+n by the first store: it's not safe to move the
849 // first store out of the loop
850 // - nothing must observe the memory Phi: it guarantees no read
851 // before the store, we are also guaranteed the store post
852 // dominates the loop head (ignoring a possible early
853 // exit). Otherwise there would be extra Phi involved between the
854 // loop's Phi and the store.
855 // - there must be no early exit from the loop before the Store
856 // (such an exit most of the time would be an extra use of the
857 // memory Phi but sometimes is a bottom memory Phi that takes the
858 // store as input).
859
860 if (!n_loop->is_member(address_loop) &&
861 !n_loop->is_member(value_loop) &&
862 mem->is_Phi() && mem->in(0) == n_loop->_head &&
863 mem->outcnt() == 1 &&
864 mem->in(LoopNode::LoopBackControl) == n) {
865
866 assert(n_loop->_tail != NULL, "need a tail");
867 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
868
869 // Verify that there's no early exit of the loop before the store.
870 bool ctrl_ok = false;
871 {
872 // Follow control from loop head until n, we exit the loop or
873 // we reach the tail
874 ResourceMark rm;
875 Unique_Node_List wq;
876 wq.push(n_loop->_head);
877
878 for (uint next = 0; next < wq.size(); ++next) {
879 Node *m = wq.at(next);
880 if (m == n->in(0)) {
881 ctrl_ok = true;
882 continue;
883 }
884 assert(!has_ctrl(m), "should be CFG");
885 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
886 ctrl_ok = false;
887 break;
888 }
889 enqueue_cfg_uses(m, wq);
890 if (wq.size() > 10) {
891 ctrl_ok = false;
892 break;
893 }
894 }
895 }
896 if (ctrl_ok) {
897 // move the Store
898 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
899 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
900 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
901 // Disconnect the phi now. An empty phi can confuse other
902 // optimizations in this pass of loop opts.
903 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
904 n_loop->_body.yank(mem);
905
906 set_ctrl_and_loop(n, n->in(0));
907
908 return n;
909 }
910 }
911 }
912 return NULL;
913 }
914
915 // Try moving a store out of a loop, right after the loop
916 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
917 if (n->is_Store() && n->in(0) != NULL) {
918 Node *n_ctrl = get_ctrl(n);
919 IdealLoopTree *n_loop = get_loop(n_ctrl);
920 // Store must be in a loop
921 if (n_loop != _ltree_root && !n_loop->_irreducible) {
922 Node* address = n->in(MemNode::Address);
923 Node* value = n->in(MemNode::ValueIn);
924 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
925 // address must be loop invariant
926 if (!n_loop->is_member(address_loop)) {
927 // Store must be last on this memory slice in the loop and
928 // nothing in the loop must observe it
929 Node* phi = NULL;
930 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
931 Node* u = n->fast_out(i);
932 if (has_ctrl(u)) { // control use?
933 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
934 if (!n_loop->is_member(u_loop)) {
935 continue;
936 }
937 if (u->is_Phi() && u->in(0) == n_loop->_head) {
938 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
939 // multiple phis on the same slice are possible
940 if (phi != NULL) {
941 return;
942 }
943 phi = u;
944 continue;
945 }
946 }
947 return;
948 }
949 if (phi != NULL) {
950 // Nothing in the loop before the store (next iteration)
951 // must observe the stored value
952 bool mem_ok = true;
953 {
954 ResourceMark rm;
955 Unique_Node_List wq;
956 wq.push(phi);
957 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
958 Node *m = wq.at(next);
959 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
960 Node* u = m->fast_out(i);
961 if (u->is_Store() || u->is_Phi()) {
962 if (u != n) {
963 wq.push(u);
964 mem_ok = (wq.size() <= 10);
965 }
966 } else {
967 mem_ok = false;
968 break;
969 }
970 }
971 }
972 }
973 if (mem_ok) {
974 // Move the store out of the loop if the LCA of all
975 // users (except for the phi) is outside the loop.
976 Node* hook = new Node(1);
977 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead
978 _igvn.rehash_node_delayed(phi);
979 int count = phi->replace_edge(n, hook, &_igvn);
980 assert(count > 0, "inconsistent phi");
981
982 // Compute latest point this store can go
983 Node* lca = get_late_ctrl(n, get_ctrl(n));
984 if (lca->is_OuterStripMinedLoop()) {
985 lca = lca->in(LoopNode::EntryControl);
986 }
987 if (n_loop->is_member(get_loop(lca))) {
988 // LCA is in the loop - bail out
989 _igvn.replace_node(hook, n);
990 return;
991 }
992 #ifdef ASSERT
993 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
994 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
995 n_loop->_head->as_Loop()->verify_strip_mined(1);
996 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
997 IdealLoopTree* outer_loop = get_loop(outer);
998 assert(n_loop->_parent == outer_loop, "broken loop tree");
999 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
1000 }
1001 #endif
1002 lca = place_outside_loop(lca, n_loop);
1003 assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop");
1004 assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch(), "must not be moved into inner loop");
1005
1006 // Move store out of the loop
1007 _igvn.replace_node(hook, n->in(MemNode::Memory));
1008 _igvn.replace_input_of(n, 0, lca);
1009 set_ctrl_and_loop(n, lca);
1010
1011 // Disconnect the phi now. An empty phi can confuse other
1012 // optimizations in this pass of loop opts..
1013 if (phi->in(LoopNode::LoopBackControl) == phi) {
1014 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
1015 n_loop->_body.yank(phi);
1016 }
1017 }
1018 }
1019 }
1020 }
1021 }
1022 }
1023
1024 //------------------------------split_if_with_blocks_pre-----------------------
1025 // Do the real work in a non-recursive function. Data nodes want to be
1026 // cloned in the pre-order so they can feed each other nicely.
1027 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
1028 // Cloning these guys is unlikely to win
1029 int n_op = n->Opcode();
1030 if (n_op == Op_MergeMem) {
1031 return n;
1032 }
1033 if (n->is_Proj()) {
1034 return n;
1035 }
1036 // Do not clone-up CmpFXXX variations, as these are always
1037 // followed by a CmpI
1038 if (n->is_Cmp()) {
1039 return n;
1040 }
1041 // Attempt to use a conditional move instead of a phi/branch
1042 if (ConditionalMoveLimit > 0 && n_op == Op_Region) {
1043 Node *cmov = conditional_move( n );
1044 if (cmov) {
1045 return cmov;
1046 }
1047 }
1048 if (n->is_CFG() || n->is_LoadStore()) {
1049 return n;
1050 }
1051 if (n->is_Opaque1()) { // Opaque nodes cannot be mod'd
1052 if (!C->major_progress()) { // If chance of no more loop opts...
1053 _igvn._worklist.push(n); // maybe we'll remove them
1054 }
1055 return n;
1056 }
1057
1058 if (n->is_Con()) {
1059 return n; // No cloning for Con nodes
1060 }
1061
1062 Node *n_ctrl = get_ctrl(n);
1063 if (!n_ctrl) {
1064 return n; // Dead node
1065 }
1066
1067 Node* res = try_move_store_before_loop(n, n_ctrl);
1068 if (res != NULL) {
1069 return n;
1070 }
1071
1072 // Attempt to remix address expressions for loop invariants
1073 Node *m = remix_address_expressions( n );
1074 if( m ) return m;
1075
1076 if (n_op == Op_AddI) {
1077 Node *nn = convert_add_to_muladd( n );
1078 if ( nn ) return nn;
1079 }
1080
1081 if (n->is_ConstraintCast()) {
1082 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
1083 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
1084 // Node control inputs don't necessarily agree with loop control info (due to
1085 // transformations happened in between), thus additional dominance check is needed
1086 // to keep loop info valid.
1087 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
1088 _igvn.replace_node(n, dom_cast);
1089 return dom_cast;
1090 }
1091 }
1092
1093 // Determine if the Node has inputs from some local Phi.
1094 // Returns the block to clone thru.
1095 Node *n_blk = has_local_phi_input( n );
1096 if( !n_blk ) return n;
1097
1098 // Do not clone the trip counter through on a CountedLoop
1099 // (messes up the canonical shape).
1100 if (((n_blk->is_CountedLoop() || (n_blk->is_Loop() && n_blk->as_Loop()->is_loop_nest_inner_loop())) && n->Opcode() == Op_AddI) ||
1101 (n_blk->is_LongCountedLoop() && n->Opcode() == Op_AddL)) {
1102 return n;
1103 }
1104 // Pushing a shift through the iv Phi can get in the way of addressing optimizations or range check elimination
1105 if (n_blk->is_BaseCountedLoop() && n->Opcode() == Op_LShift(n_blk->as_BaseCountedLoop()->bt()) &&
1106 n->in(1) == n_blk->as_BaseCountedLoop()->phi()) {
1107 return n;
1108 }
1109
1110 // Check for having no control input; not pinned. Allow
1111 // dominating control.
1112 if (n->in(0)) {
1113 Node *dom = idom(n_blk);
1114 if (dom_lca(n->in(0), dom) != n->in(0)) {
1115 return n;
1116 }
1117 }
1118 // Policy: when is it profitable. You must get more wins than
1119 // policy before it is considered profitable. Policy is usually 0,
1120 // so 1 win is considered profitable. Big merges will require big
1121 // cloning, so get a larger policy.
1122 int policy = n_blk->req() >> 2;
1123
1124 // If the loop is a candidate for range check elimination,
1125 // delay splitting through it's phi until a later loop optimization
1126 if (n_blk->is_BaseCountedLoop()) {
1127 IdealLoopTree *lp = get_loop(n_blk);
1128 if (lp && lp->_rce_candidate) {
1129 return n;
1130 }
1131 }
1132
1133 if (must_throttle_split_if()) return n;
1134
1135 // Split 'n' through the merge point if it is profitable
1136 Node *phi = split_thru_phi( n, n_blk, policy );
1137 if (!phi) return n;
1138
1139 // Found a Phi to split thru!
1140 // Replace 'n' with the new phi
1141 _igvn.replace_node( n, phi );
1142 // Moved a load around the loop, 'en-registering' something.
1143 if (n_blk->is_Loop() && n->is_Load() &&
1144 !phi->in(LoopNode::LoopBackControl)->is_Load())
1145 C->set_major_progress();
1146
1147 return phi;
1148 }
1149
1150 static bool merge_point_too_heavy(Compile* C, Node* region) {
1151 // Bail out if the region and its phis have too many users.
1152 int weight = 0;
1153 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1154 weight += region->fast_out(i)->outcnt();
1155 }
1156 int nodes_left = C->max_node_limit() - C->live_nodes();
1157 if (weight * 8 > nodes_left) {
1158 if (PrintOpto) {
1159 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
1160 }
1161 return true;
1162 } else {
1163 return false;
1164 }
1165 }
1166
1167 static bool merge_point_safe(Node* region) {
1168 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1169 // having a PhiNode input. This sidesteps the dangerous case where the split
1170 // ConvI2LNode may become TOP if the input Value() does not
1171 // overlap the ConvI2L range, leaving a node which may not dominate its
1172 // uses.
1173 // A better fix for this problem can be found in the BugTraq entry, but
1174 // expediency for Mantis demands this hack.
1175 #ifdef _LP64
1176 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1177 Node* n = region->fast_out(i);
1178 if (n->is_Phi()) {
1179 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1180 Node* m = n->fast_out(j);
1181 if (m->Opcode() == Op_ConvI2L)
1182 return false;
1183 if (m->is_CastII()) {
1184 return false;
1185 }
1186 }
1187 }
1188 }
1189 #endif
1190 return true;
1191 }
1192
1193
1194 //------------------------------place_outside_loop---------------------------------
1195 // Place some computation outside of this loop on the path to the use passed as argument
1196 Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) const {
1197 Node* head = loop->_head;
1198 assert(!loop->is_member(get_loop(useblock)), "must be outside loop");
1199 if (head->is_Loop() && head->as_Loop()->is_strip_mined()) {
1200 loop = loop->_parent;
1201 assert(loop->_head->is_OuterStripMinedLoop(), "malformed strip mined loop");
1202 }
1203
1204 // Pick control right outside the loop
1205 for (;;) {
1206 Node* dom = idom(useblock);
1207 if (loop->is_member(get_loop(dom)) ||
1208 // NeverBranch nodes are not assigned to the loop when constructed
1209 (dom->is_NeverBranch() && loop->is_member(get_loop(dom->in(0))))) {
1210 break;
1211 }
1212 useblock = dom;
1213 }
1214 assert(find_non_split_ctrl(useblock) == useblock, "should be non split control");
1215 return useblock;
1216 }
1217
1218
1219 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1220 if (!n->is_If() || n->is_BaseCountedLoopEnd()) {
1221 return false;
1222 }
1223 if (!n->in(0)->is_Region()) {
1224 return false;
1225 }
1226
1227 Node* region = n->in(0);
1228 Node* dom = idom(region);
1229 if (!dom->is_If() || dom->in(1) != n->in(1)) {
1230 return false;
1231 }
1232 IfNode* dom_if = dom->as_If();
1233 Node* proj_true = dom_if->proj_out(1);
1234 Node* proj_false = dom_if->proj_out(0);
1235
1236 for (uint i = 1; i < region->req(); i++) {
1237 if (is_dominator(proj_true, region->in(i))) {
1238 continue;
1239 }
1240 if (is_dominator(proj_false, region->in(i))) {
1241 continue;
1242 }
1243 return false;
1244 }
1245
1246 return true;
1247 }
1248
1249
1250 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) {
1251 if (must_throttle_split_if()) {
1252 return false;
1253 }
1254
1255 // Do not do 'split-if' if irreducible loops are present.
1256 if (_has_irreducible_loops) {
1257 return false;
1258 }
1259
1260 if (merge_point_too_heavy(C, n_ctrl)) {
1261 return false;
1262 }
1263
1264 // Do not do 'split-if' if some paths are dead. First do dead code
1265 // elimination and then see if its still profitable.
1266 for (uint i = 1; i < n_ctrl->req(); i++) {
1267 if (n_ctrl->in(i) == C->top()) {
1268 return false;
1269 }
1270 }
1271
1272 // If trying to do a 'Split-If' at the loop head, it is only
1273 // profitable if the cmp folds up on BOTH paths. Otherwise we
1274 // risk peeling a loop forever.
1275
1276 // CNC - Disabled for now. Requires careful handling of loop
1277 // body selection for the cloned code. Also, make sure we check
1278 // for any input path not being in the same loop as n_ctrl. For
1279 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1280 // because the alternative loop entry points won't be converted
1281 // into LoopNodes.
1282 IdealLoopTree *n_loop = get_loop(n_ctrl);
1283 for (uint j = 1; j < n_ctrl->req(); j++) {
1284 if (get_loop(n_ctrl->in(j)) != n_loop) {
1285 return false;
1286 }
1287 }
1288
1289 // Check for safety of the merge point.
1290 if (!merge_point_safe(n_ctrl)) {
1291 return false;
1292 }
1293
1294 return true;
1295 }
1296
1297 // Detect if the node is the inner strip-mined loop
1298 // Return: NULL if it's not the case, or the exit of outer strip-mined loop
1299 static Node* is_inner_of_stripmined_loop(const Node* out) {
1300 Node* out_le = NULL;
1301
1302 if (out->is_CountedLoopEnd()) {
1303 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode();
1304
1305 if (loop != NULL && loop->is_strip_mined()) {
1306 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit();
1307 }
1308 }
1309
1310 return out_le;
1311 }
1312
1313 //------------------------------split_if_with_blocks_post----------------------
1314 // Do the real work in a non-recursive function. CFG hackery wants to be
1315 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1316 // info.
1317 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1318
1319 // Cloning Cmp through Phi's involves the split-if transform.
1320 // FastLock is not used by an If
1321 if (n->is_Cmp() && !n->is_FastLock()) {
1322 Node *n_ctrl = get_ctrl(n);
1323 // Determine if the Node has inputs from some local Phi.
1324 // Returns the block to clone thru.
1325 Node *n_blk = has_local_phi_input(n);
1326 if (n_blk != n_ctrl) {
1327 return;
1328 }
1329
1330 if (!can_split_if(n_ctrl)) {
1331 return;
1332 }
1333
1334 if (n->outcnt() != 1) {
1335 return; // Multiple bool's from 1 compare?
1336 }
1337 Node *bol = n->unique_out();
1338 assert(bol->is_Bool(), "expect a bool here");
1339 if (bol->outcnt() != 1) {
1340 return;// Multiple branches from 1 compare?
1341 }
1342 Node *iff = bol->unique_out();
1343
1344 // Check some safety conditions
1345 if (iff->is_If()) { // Classic split-if?
1346 if (iff->in(0) != n_ctrl) {
1347 return; // Compare must be in same blk as if
1348 }
1349 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1350 // Can't split CMove with different control edge.
1351 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) {
1352 return;
1353 }
1354 if (get_ctrl(iff->in(2)) == n_ctrl ||
1355 get_ctrl(iff->in(3)) == n_ctrl) {
1356 return; // Inputs not yet split-up
1357 }
1358 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1359 return; // Loop-invar test gates loop-varying CMOVE
1360 }
1361 } else {
1362 return; // some other kind of node, such as an Allocate
1363 }
1364
1365 // When is split-if profitable? Every 'win' on means some control flow
1366 // goes dead, so it's almost always a win.
1367 int policy = 0;
1368 // Split compare 'n' through the merge point if it is profitable
1369 Node *phi = split_thru_phi( n, n_ctrl, policy);
1370 if (!phi) {
1371 return;
1372 }
1373
1374 // Found a Phi to split thru!
1375 // Replace 'n' with the new phi
1376 _igvn.replace_node(n, phi);
1377
1378 // Now split the bool up thru the phi
1379 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1380 guarantee(bolphi != NULL, "null boolean phi node");
1381
1382 _igvn.replace_node(bol, bolphi);
1383 assert(iff->in(1) == bolphi, "");
1384
1385 if (bolphi->Value(&_igvn)->singleton()) {
1386 return;
1387 }
1388
1389 // Conditional-move? Must split up now
1390 if (!iff->is_If()) {
1391 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1392 _igvn.replace_node(iff, cmovphi);
1393 return;
1394 }
1395
1396 // Now split the IF
1397 do_split_if(iff);
1398 return;
1399 }
1400
1401 // Two identical ifs back to back can be merged
1402 if (try_merge_identical_ifs(n)) {
1403 return;
1404 }
1405
1406 // Check for an IF ready to split; one that has its
1407 // condition codes input coming from a Phi at the block start.
1408 int n_op = n->Opcode();
1409
1410 // Check for an IF being dominated by another IF same test
1411 if (n_op == Op_If ||
1412 n_op == Op_RangeCheck) {
1413 Node *bol = n->in(1);
1414 uint max = bol->outcnt();
1415 // Check for same test used more than once?
1416 if (max > 1 && bol->is_Bool()) {
1417 // Search up IDOMs to see if this IF is dominated.
1418 Node *cutoff = get_ctrl(bol);
1419
1420 // Now search up IDOMs till cutoff, looking for a dominating test
1421 Node *prevdom = n;
1422 Node *dom = idom(prevdom);
1423 while (dom != cutoff) {
1424 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom &&
1425 safe_for_if_replacement(dom)) {
1426 // It's invalid to move control dependent data nodes in the inner
1427 // strip-mined loop, because:
1428 // 1) break validation of LoopNode::verify_strip_mined()
1429 // 2) move code with side-effect in strip-mined loop
1430 // Move to the exit of outer strip-mined loop in that case.
1431 Node* out_le = is_inner_of_stripmined_loop(dom);
1432 if (out_le != NULL) {
1433 prevdom = out_le;
1434 }
1435 // Replace the dominated test with an obvious true or false.
1436 // Place it on the IGVN worklist for later cleanup.
1437 C->set_major_progress();
1438 dominated_by(prevdom->as_IfProj(), n->as_If(), false, true);
1439 #ifndef PRODUCT
1440 if( VerifyLoopOptimizations ) verify();
1441 #endif
1442 return;
1443 }
1444 prevdom = dom;
1445 dom = idom(prevdom);
1446 }
1447 }
1448 }
1449
1450 try_sink_out_of_loop(n);
1451
1452 try_move_store_after_loop(n);
1453 }
1454
1455 // Transform:
1456 //
1457 // if (some_condition) {
1458 // // body 1
1459 // } else {
1460 // // body 2
1461 // }
1462 // if (some_condition) {
1463 // // body 3
1464 // } else {
1465 // // body 4
1466 // }
1467 //
1468 // into:
1469 //
1470 //
1471 // if (some_condition) {
1472 // // body 1
1473 // // body 3
1474 // } else {
1475 // // body 2
1476 // // body 4
1477 // }
1478 bool PhaseIdealLoop::try_merge_identical_ifs(Node* n) {
1479 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1480 Node *n_ctrl = n->in(0);
1481 IfNode* dom_if = idom(n_ctrl)->as_If();
1482 ProjNode* dom_proj_true = dom_if->proj_out(1);
1483 ProjNode* dom_proj_false = dom_if->proj_out(0);
1484
1485 // Now split the IF
1486 RegionNode* new_false_region;
1487 RegionNode* new_true_region;
1488 do_split_if(n, &new_false_region, &new_true_region);
1489 assert(new_false_region->req() == new_true_region->req(), "");
1490 #ifdef ASSERT
1491 for (uint i = 1; i < new_false_region->req(); ++i) {
1492 assert(new_false_region->in(i)->in(0) == new_true_region->in(i)->in(0), "unexpected shape following split if");
1493 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");
1494 }
1495 #endif
1496 assert(new_false_region->in(1)->in(0)->in(1) == dom_if->in(1), "dominating if and dominated if after split must share test");
1497
1498 // We now have:
1499 // if (some_condition) {
1500 // // body 1
1501 // if (some_condition) {
1502 // body3: // new_true_region
1503 // // body3
1504 // } else {
1505 // goto body4;
1506 // }
1507 // } else {
1508 // // body 2
1509 // if (some_condition) {
1510 // goto body3;
1511 // } else {
1512 // body4: // new_false_region
1513 // // body4;
1514 // }
1515 // }
1516 //
1517
1518 // clone pinned nodes thru the resulting regions
1519 push_pinned_nodes_thru_region(dom_if, new_true_region);
1520 push_pinned_nodes_thru_region(dom_if, new_false_region);
1521
1522 // Optimize out the cloned ifs. Because pinned nodes were cloned, this also allows a CastPP that would be dependent
1523 // 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
1524 // unrelated control dependency.
1525 for (uint i = 1; i < new_false_region->req(); i++) {
1526 if (is_dominator(dom_proj_true, new_false_region->in(i))) {
1527 dominated_by(dom_proj_true->as_IfProj(), new_false_region->in(i)->in(0)->as_If(), false, false);
1528 } else {
1529 assert(is_dominator(dom_proj_false, new_false_region->in(i)), "bad if");
1530 dominated_by(dom_proj_false->as_IfProj(), new_false_region->in(i)->in(0)->as_If(), false, false);
1531 }
1532 }
1533 return true;
1534 }
1535 return false;
1536 }
1537
1538 void PhaseIdealLoop::push_pinned_nodes_thru_region(IfNode* dom_if, Node* region) {
1539 for (DUIterator i = region->outs(); region->has_out(i); i++) {
1540 Node* u = region->out(i);
1541 if (!has_ctrl(u) || u->is_Phi() || !u->depends_only_on_test() || !_igvn.no_dependent_zero_check(u)) {
1542 continue;
1543 }
1544 assert(u->in(0) == region, "not a control dependent node?");
1545 uint j = 1;
1546 for (; j < u->req(); ++j) {
1547 Node* in = u->in(j);
1548 if (!is_dominator(ctrl_or_self(in), dom_if)) {
1549 break;
1550 }
1551 }
1552 if (j == u->req()) {
1553 Node *phi = PhiNode::make_blank(region, u);
1554 for (uint k = 1; k < region->req(); ++k) {
1555 Node* clone = u->clone();
1556 clone->set_req(0, region->in(k));
1557 register_new_node(clone, region->in(k));
1558 phi->init_req(k, clone);
1559 }
1560 register_new_node(phi, region);
1561 _igvn.replace_node(u, phi);
1562 --i;
1563 }
1564 }
1565 }
1566
1567 bool PhaseIdealLoop::safe_for_if_replacement(const Node* dom) const {
1568 if (!dom->is_CountedLoopEnd()) {
1569 return true;
1570 }
1571 CountedLoopEndNode* le = dom->as_CountedLoopEnd();
1572 CountedLoopNode* cl = le->loopnode();
1573 if (cl == NULL) {
1574 return true;
1575 }
1576 if (!cl->is_main_loop()) {
1577 return true;
1578 }
1579 if (cl->is_canonical_loop_entry() == NULL) {
1580 return true;
1581 }
1582 // Further unrolling is possible so loop exit condition might change
1583 return false;
1584 }
1585
1586 // See if a shared loop-varying computation has no loop-varying uses.
1587 // Happens if something is only used for JVM state in uncommon trap exits,
1588 // like various versions of induction variable+offset. Clone the
1589 // computation per usage to allow it to sink out of the loop.
1590 void PhaseIdealLoop::try_sink_out_of_loop(Node* n) {
1591 if (has_ctrl(n) &&
1592 !n->is_Phi() &&
1593 !n->is_Bool() &&
1594 !n->is_Proj() &&
1595 !n->is_MergeMem() &&
1596 !n->is_CMove() &&
1597 n->Opcode() != Op_Opaque4 &&
1598 !n->is_Type()) {
1599 Node *n_ctrl = get_ctrl(n);
1600 IdealLoopTree *n_loop = get_loop(n_ctrl);
1601
1602 if (n->in(0) != NULL) {
1603 IdealLoopTree* loop_ctrl = get_loop(n->in(0));
1604 if (n_loop != loop_ctrl && n_loop->is_member(loop_ctrl)) {
1605 // n has a control input inside a loop but get_ctrl() is member of an outer loop. This could happen, for example,
1606 // for Div nodes inside a loop (control input inside loop) without a use except for an UCT (outside the loop).
1607 // Rewire control of n to right outside of the loop, regardless if its input(s) are later sunk or not.
1608 _igvn.replace_input_of(n, 0, place_outside_loop(n_ctrl, loop_ctrl));
1609 }
1610 }
1611 if (n_loop != _ltree_root && n->outcnt() > 1) {
1612 // Compute early control: needed for anti-dependence analysis. It's also possible that as a result of
1613 // previous transformations in this loop opts round, the node can be hoisted now: early control will tell us.
1614 Node* early_ctrl = compute_early_ctrl(n, n_ctrl);
1615 if (n_loop->is_member(get_loop(early_ctrl)) && // check that this one can't be hoisted now
1616 ctrl_of_all_uses_out_of_loop(n, early_ctrl, n_loop)) { // All uses in outer loops!
1617 assert(!n->is_Store() && !n->is_LoadStore(), "no node with a side effect");
1618 Node* outer_loop_clone = NULL;
1619 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin;) {
1620 Node* u = n->last_out(j); // Clone private computation per use
1621 _igvn.rehash_node_delayed(u);
1622 Node* x = n->clone(); // Clone computation
1623 Node* x_ctrl = NULL;
1624 if (u->is_Phi()) {
1625 // Replace all uses of normal nodes. Replace Phi uses
1626 // individually, so the separate Nodes can sink down
1627 // different paths.
1628 uint k = 1;
1629 while (u->in(k) != n) k++;
1630 u->set_req(k, x);
1631 // x goes next to Phi input path
1632 x_ctrl = u->in(0)->in(k);
1633 // Find control for 'x' next to use but not inside inner loops.
1634 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1635 --j;
1636 } else { // Normal use
1637 if (has_ctrl(u)) {
1638 x_ctrl = get_ctrl(u);
1639 } else {
1640 x_ctrl = u->in(0);
1641 }
1642 // Find control for 'x' next to use but not inside inner loops.
1643 x_ctrl = place_outside_loop(x_ctrl, n_loop);
1644 // Replace all uses
1645 if (u->is_ConstraintCast() && u->bottom_type()->higher_equal(_igvn.type(n)) && u->in(0) == x_ctrl) {
1646 // If we're sinking a chain of data nodes, we might have inserted a cast to pin the use which is not necessary
1647 // anymore now that we're going to pin n as well
1648 _igvn.replace_node(u, x);
1649 --j;
1650 } else {
1651 int nb = u->replace_edge(n, x, &_igvn);
1652 j -= nb;
1653 }
1654 }
1655
1656 if (n->is_Load()) {
1657 // For loads, add a control edge to a CFG node outside of the loop
1658 // to force them to not combine and return back inside the loop
1659 // during GVN optimization (4641526).
1660 assert(x_ctrl == get_late_ctrl_with_anti_dep(x->as_Load(), early_ctrl, x_ctrl), "anti-dependences were already checked");
1661
1662 IdealLoopTree* x_loop = get_loop(x_ctrl);
1663 Node* x_head = x_loop->_head;
1664 if (x_head->is_Loop() && x_head->is_OuterStripMinedLoop()) {
1665 // Do not add duplicate LoadNodes to the outer strip mined loop
1666 if (outer_loop_clone != NULL) {
1667 _igvn.replace_node(x, outer_loop_clone);
1668 continue;
1669 }
1670 outer_loop_clone = x;
1671 }
1672 x->set_req(0, x_ctrl);
1673 } else if (n->in(0) != NULL){
1674 x->set_req(0, x_ctrl);
1675 }
1676 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1677 assert(!n_loop->is_member(get_loop(x_ctrl)), "should have moved out of loop");
1678 register_new_node(x, x_ctrl);
1679
1680 // Chain of AddP: (AddP base (AddP base )) must keep the same base after sinking so:
1681 // 1- We don't add a CastPP here when the first one is sunk so if the second one is not, their bases remain
1682 // the same.
1683 // (see 2- below)
1684 assert(!x->is_AddP() || !x->in(AddPNode::Address)->is_AddP() ||
1685 x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base) ||
1686 !x->in(AddPNode::Address)->in(AddPNode::Base)->eqv_uncast(x->in(AddPNode::Base)), "unexpected AddP shape");
1687 if (x->in(0) == NULL && !x->is_DecodeNarrowPtr() &&
1688 !(x->is_AddP() && x->in(AddPNode::Address)->is_AddP() && x->in(AddPNode::Address)->in(AddPNode::Base) == x->in(AddPNode::Base))) {
1689 assert(!x->is_Load(), "load should be pinned");
1690 // Use a cast node to pin clone out of loop
1691 Node* cast = NULL;
1692 for (uint k = 0; k < x->req(); k++) {
1693 Node* in = x->in(k);
1694 if (in != NULL && n_loop->is_member(get_loop(get_ctrl(in)))) {
1695 const Type* in_t = _igvn.type(in);
1696 cast = ConstraintCastNode::make_cast_for_type(x_ctrl, in, in_t, ConstraintCastNode::UnconditionalDependency);
1697 }
1698 if (cast != NULL) {
1699 register_new_node(cast, x_ctrl);
1700 x->replace_edge(in, cast);
1701 // Chain of AddP:
1702 // 2- A CastPP of the base is only added now that both AddP nodes are sunk
1703 if (x->is_AddP() && k == AddPNode::Base) {
1704 for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1705 Node* u = x->fast_out(i);
1706 if (u->is_AddP() && u->in(AddPNode::Base) == n->in(AddPNode::Base)) {
1707 _igvn.replace_input_of(u, AddPNode::Base, cast);
1708 assert(u->find_out_with(Op_AddP) == NULL, "more than 2 chained AddP nodes?");
1709 }
1710 }
1711 }
1712 break;
1713 }
1714 }
1715 assert(cast != NULL, "must have added a cast to pin the node");
1716 }
1717 }
1718 _igvn.remove_dead_node(n);
1719 }
1720 _dom_lca_tags_round = 0;
1721 }
1722 }
1723 }
1724
1725 // Compute the early control of a node by following its inputs until we reach
1726 // nodes that are pinned. Then compute the LCA of the control of all pinned nodes.
1727 Node* PhaseIdealLoop::compute_early_ctrl(Node* n, Node* n_ctrl) {
1728 Node* early_ctrl = NULL;
1729 ResourceMark rm;
1730 Unique_Node_List wq;
1731 wq.push(n);
1732 for (uint i = 0; i < wq.size(); i++) {
1733 Node* m = wq.at(i);
1734 Node* c = NULL;
1735 if (m->is_CFG()) {
1736 c = m;
1737 } else if (m->pinned()) {
1738 c = m->in(0);
1739 } else {
1740 for (uint j = 0; j < m->req(); j++) {
1741 Node* in = m->in(j);
1742 if (in != NULL) {
1743 wq.push(in);
1744 }
1745 }
1746 }
1747 if (c != NULL) {
1748 assert(is_dominator(c, n_ctrl), "control input must dominate current control");
1749 if (early_ctrl == NULL || is_dominator(early_ctrl, c)) {
1750 early_ctrl = c;
1751 }
1752 }
1753 }
1754 assert(is_dominator(early_ctrl, n_ctrl), "early control must dominate current control");
1755 return early_ctrl;
1756 }
1757
1758 bool PhaseIdealLoop::ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop) {
1759 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1760 Node* u = n->fast_out(i);
1761 if (u->is_Opaque1()) {
1762 return false; // Found loop limit, bugfix for 4677003
1763 }
1764 // We can't reuse tags in PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal() so make sure calls to
1765 // get_late_ctrl_with_anti_dep() use their own tag
1766 _dom_lca_tags_round++;
1767 assert(_dom_lca_tags_round != 0, "shouldn't wrap around");
1768
1769 if (u->is_Phi()) {
1770 for (uint j = 1; j < u->req(); ++j) {
1771 if (u->in(j) == n && !ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, u->in(0)->in(j))) {
1772 return false;
1773 }
1774 }
1775 } else {
1776 Node* ctrl = has_ctrl(u) ? get_ctrl(u) : u->in(0);
1777 if (!ctrl_of_use_out_of_loop(n, n_ctrl, n_loop, ctrl)) {
1778 return false;
1779 }
1780 }
1781 }
1782 return true;
1783 }
1784
1785 bool PhaseIdealLoop::ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl) {
1786 if (n->is_Load()) {
1787 ctrl = get_late_ctrl_with_anti_dep(n->as_Load(), n_ctrl, ctrl);
1788 }
1789 IdealLoopTree *u_loop = get_loop(ctrl);
1790 if (u_loop == n_loop) {
1791 return false; // Found loop-varying use
1792 }
1793 if (n_loop->is_member(u_loop)) {
1794 return false; // Found use in inner loop
1795 }
1796 return true;
1797 }
1798
1799 //------------------------------split_if_with_blocks---------------------------
1800 // Check for aggressive application of 'split-if' optimization,
1801 // using basic block level info.
1802 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) {
1803 Node* root = C->root();
1804 visited.set(root->_idx); // first, mark root as visited
1805 // Do pre-visit work for root
1806 Node* n = split_if_with_blocks_pre(root);
1807 uint cnt = n->outcnt();
1808 uint i = 0;
1809
1810 while (true) {
1811 // Visit all children
1812 if (i < cnt) {
1813 Node* use = n->raw_out(i);
1814 ++i;
1815 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1816 // Now do pre-visit work for this use
1817 use = split_if_with_blocks_pre(use);
1818 nstack.push(n, i); // Save parent and next use's index.
1819 n = use; // Process all children of current use.
1820 cnt = use->outcnt();
1821 i = 0;
1822 }
1823 }
1824 else {
1825 // All of n's children have been processed, complete post-processing.
1826 if (cnt != 0 && !n->is_Con()) {
1827 assert(has_node(n), "no dead nodes");
1828 split_if_with_blocks_post(n);
1829 }
1830 if (must_throttle_split_if()) {
1831 nstack.clear();
1832 }
1833 if (nstack.is_empty()) {
1834 // Finished all nodes on stack.
1835 break;
1836 }
1837 // Get saved parent node and next use's index. Visit the rest of uses.
1838 n = nstack.node();
1839 cnt = n->outcnt();
1840 i = nstack.index();
1841 nstack.pop();
1842 }
1843 }
1844 }
1845
1846
1847 //=============================================================================
1848 //
1849 // C L O N E A L O O P B O D Y
1850 //
1851
1852 //------------------------------clone_iff--------------------------------------
1853 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1854 // "Nearly" because all Nodes have been cloned from the original in the loop,
1855 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1856 // through the Phi recursively, and return a Bool.
1857 Node* PhaseIdealLoop::clone_iff(PhiNode* phi) {
1858
1859 // Convert this Phi into a Phi merging Bools
1860 uint i;
1861 for (i = 1; i < phi->req(); i++) {
1862 Node *b = phi->in(i);
1863 if (b->is_Phi()) {
1864 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi()));
1865 } else {
1866 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
1867 }
1868 }
1869
1870 Node* n = phi->in(1);
1871 Node* sample_opaque = NULL;
1872 Node *sample_bool = NULL;
1873 if (n->Opcode() == Op_Opaque4) {
1874 sample_opaque = n;
1875 sample_bool = n->in(1);
1876 assert(sample_bool->is_Bool(), "wrong type");
1877 } else {
1878 sample_bool = n;
1879 }
1880 Node *sample_cmp = sample_bool->in(1);
1881
1882 // Make Phis to merge the Cmp's inputs.
1883 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
1884 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
1885 for (i = 1; i < phi->req(); i++) {
1886 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
1887 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
1888 phi1->set_req(i, n1);
1889 phi2->set_req(i, n2);
1890 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1891 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1892 }
1893 // See if these Phis have been made before.
1894 // Register with optimizer
1895 Node *hit1 = _igvn.hash_find_insert(phi1);
1896 if (hit1) { // Hit, toss just made Phi
1897 _igvn.remove_dead_node(phi1); // Remove new phi
1898 assert(hit1->is_Phi(), "" );
1899 phi1 = (PhiNode*)hit1; // Use existing phi
1900 } else { // Miss
1901 _igvn.register_new_node_with_optimizer(phi1);
1902 }
1903 Node *hit2 = _igvn.hash_find_insert(phi2);
1904 if (hit2) { // Hit, toss just made Phi
1905 _igvn.remove_dead_node(phi2); // Remove new phi
1906 assert(hit2->is_Phi(), "" );
1907 phi2 = (PhiNode*)hit2; // Use existing phi
1908 } else { // Miss
1909 _igvn.register_new_node_with_optimizer(phi2);
1910 }
1911 // Register Phis with loop/block info
1912 set_ctrl(phi1, phi->in(0));
1913 set_ctrl(phi2, phi->in(0));
1914 // Make a new Cmp
1915 Node *cmp = sample_cmp->clone();
1916 cmp->set_req(1, phi1);
1917 cmp->set_req(2, phi2);
1918 _igvn.register_new_node_with_optimizer(cmp);
1919 set_ctrl(cmp, phi->in(0));
1920
1921 // Make a new Bool
1922 Node *b = sample_bool->clone();
1923 b->set_req(1,cmp);
1924 _igvn.register_new_node_with_optimizer(b);
1925 set_ctrl(b, phi->in(0));
1926
1927 if (sample_opaque != NULL) {
1928 Node* opaque = sample_opaque->clone();
1929 opaque->set_req(1, b);
1930 _igvn.register_new_node_with_optimizer(opaque);
1931 set_ctrl(opaque, phi->in(0));
1932 return opaque;
1933 }
1934
1935 assert(b->is_Bool(), "");
1936 return b;
1937 }
1938
1939 //------------------------------clone_bool-------------------------------------
1940 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1941 // "Nearly" because all Nodes have been cloned from the original in the loop,
1942 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1943 // through the Phi recursively, and return a Bool.
1944 CmpNode*PhaseIdealLoop::clone_bool(PhiNode* phi) {
1945 uint i;
1946 // Convert this Phi into a Phi merging Bools
1947 for( i = 1; i < phi->req(); i++ ) {
1948 Node *b = phi->in(i);
1949 if( b->is_Phi() ) {
1950 _igvn.replace_input_of(phi, i, clone_bool(b->as_Phi()));
1951 } else {
1952 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
1953 }
1954 }
1955
1956 Node *sample_cmp = phi->in(1);
1957
1958 // Make Phis to merge the Cmp's inputs.
1959 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
1960 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
1961 for( uint j = 1; j < phi->req(); j++ ) {
1962 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
1963 Node *n1, *n2;
1964 if( cmp_top->is_Cmp() ) {
1965 n1 = cmp_top->in(1);
1966 n2 = cmp_top->in(2);
1967 } else {
1968 n1 = n2 = cmp_top;
1969 }
1970 phi1->set_req( j, n1 );
1971 phi2->set_req( j, n2 );
1972 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1973 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1974 }
1975
1976 // See if these Phis have been made before.
1977 // Register with optimizer
1978 Node *hit1 = _igvn.hash_find_insert(phi1);
1979 if( hit1 ) { // Hit, toss just made Phi
1980 _igvn.remove_dead_node(phi1); // Remove new phi
1981 assert( hit1->is_Phi(), "" );
1982 phi1 = (PhiNode*)hit1; // Use existing phi
1983 } else { // Miss
1984 _igvn.register_new_node_with_optimizer(phi1);
1985 }
1986 Node *hit2 = _igvn.hash_find_insert(phi2);
1987 if( hit2 ) { // Hit, toss just made Phi
1988 _igvn.remove_dead_node(phi2); // Remove new phi
1989 assert( hit2->is_Phi(), "" );
1990 phi2 = (PhiNode*)hit2; // Use existing phi
1991 } else { // Miss
1992 _igvn.register_new_node_with_optimizer(phi2);
1993 }
1994 // Register Phis with loop/block info
1995 set_ctrl(phi1, phi->in(0));
1996 set_ctrl(phi2, phi->in(0));
1997 // Make a new Cmp
1998 Node *cmp = sample_cmp->clone();
1999 cmp->set_req( 1, phi1 );
2000 cmp->set_req( 2, phi2 );
2001 _igvn.register_new_node_with_optimizer(cmp);
2002 set_ctrl(cmp, phi->in(0));
2003
2004 assert( cmp->is_Cmp(), "" );
2005 return (CmpNode*)cmp;
2006 }
2007
2008 //------------------------------sink_use---------------------------------------
2009 // If 'use' was in the loop-exit block, it now needs to be sunk
2010 // below the post-loop merge point.
2011 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
2012 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
2013 set_ctrl(use, post_loop);
2014 for (DUIterator j = use->outs(); use->has_out(j); j++)
2015 sink_use(use->out(j), post_loop);
2016 }
2017 }
2018
2019 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
2020 IdealLoopTree* loop, IdealLoopTree* outer_loop,
2021 Node_List*& split_if_set, Node_List*& split_bool_set,
2022 Node_List*& split_cex_set, Node_List& worklist,
2023 uint new_counter, CloneLoopMode mode) {
2024 Node* nnn = old_new[old->_idx];
2025 // Copy uses to a worklist, so I can munge the def-use info
2026 // with impunity.
2027 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2028 worklist.push(old->fast_out(j));
2029
2030 while( worklist.size() ) {
2031 Node *use = worklist.pop();
2032 if (!has_node(use)) continue; // Ignore dead nodes
2033 if (use->in(0) == C->top()) continue;
2034 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2035 // Check for data-use outside of loop - at least one of OLD or USE
2036 // must not be a CFG node.
2037 #ifdef ASSERT
2038 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) {
2039 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
2040 assert(mode != IgnoreStripMined, "incorrect cloning mode");
2041 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node");
2042 }
2043 #endif
2044 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
2045
2046 // If the Data use is an IF, that means we have an IF outside of the
2047 // loop that is switching on a condition that is set inside of the
2048 // loop. Happens if people set a loop-exit flag; then test the flag
2049 // in the loop to break the loop, then test is again outside of the
2050 // loop to determine which way the loop exited.
2051 // Loop predicate If node connects to Bool node through Opaque1 node.
2052 //
2053 // If the use is an AllocateArray through its ValidLengthTest input,
2054 // make sure the Bool/Cmp input is cloned down to avoid a Phi between
2055 // the AllocateArray node and its ValidLengthTest input that could cause
2056 // split if to break.
2057 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4 ||
2058 (use->Opcode() == Op_AllocateArray && use->in(AllocateNode::ValidLengthTest) == old)) {
2059 // Since this code is highly unlikely, we lazily build the worklist
2060 // of such Nodes to go split.
2061 if (!split_if_set) {
2062 split_if_set = new Node_List();
2063 }
2064 split_if_set->push(use);
2065 }
2066 if (use->is_Bool()) {
2067 if (!split_bool_set) {
2068 split_bool_set = new Node_List();
2069 }
2070 split_bool_set->push(use);
2071 }
2072 if (use->Opcode() == Op_CreateEx) {
2073 if (!split_cex_set) {
2074 split_cex_set = new Node_List();
2075 }
2076 split_cex_set->push(use);
2077 }
2078
2079
2080 // Get "block" use is in
2081 uint idx = 0;
2082 while( use->in(idx) != old ) idx++;
2083 Node *prev = use->is_CFG() ? use : get_ctrl(use);
2084 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
2085 Node *cfg = prev->_idx >= new_counter
2086 ? prev->in(2)
2087 : idom(prev);
2088 if( use->is_Phi() ) // Phi use is in prior block
2089 cfg = prev->in(idx); // NOT in block of Phi itself
2090 if (cfg->is_top()) { // Use is dead?
2091 _igvn.replace_input_of(use, idx, C->top());
2092 continue;
2093 }
2094
2095 // If use is referenced through control edge... (idx == 0)
2096 if (mode == IgnoreStripMined && idx == 0) {
2097 LoopNode *head = loop->_head->as_Loop();
2098 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
2099 // That node is outside the inner loop, leave it outside the
2100 // outer loop as well to not confuse verification code.
2101 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
2102 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
2103 continue;
2104 }
2105 }
2106
2107 while(!outer_loop->is_member(get_loop(cfg))) {
2108 prev = cfg;
2109 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
2110 }
2111 // If the use occurs after merging several exits from the loop, then
2112 // old value must have dominated all those exits. Since the same old
2113 // value was used on all those exits we did not need a Phi at this
2114 // merge point. NOW we do need a Phi here. Each loop exit value
2115 // is now merged with the peeled body exit; each exit gets its own
2116 // private Phi and those Phis need to be merged here.
2117 Node *phi;
2118 if( prev->is_Region() ) {
2119 if( idx == 0 ) { // Updating control edge?
2120 phi = prev; // Just use existing control
2121 } else { // Else need a new Phi
2122 phi = PhiNode::make( prev, old );
2123 // Now recursively fix up the new uses of old!
2124 for( uint i = 1; i < prev->req(); i++ ) {
2125 worklist.push(phi); // Onto worklist once for each 'old' input
2126 }
2127 }
2128 } else {
2129 // Get new RegionNode merging old and new loop exits
2130 prev = old_new[prev->_idx];
2131 assert( prev, "just made this in step 7" );
2132 if( idx == 0) { // Updating control edge?
2133 phi = prev; // Just use existing control
2134 } else { // Else need a new Phi
2135 // Make a new Phi merging data values properly
2136 phi = PhiNode::make( prev, old );
2137 phi->set_req( 1, nnn );
2138 }
2139 }
2140 // If inserting a new Phi, check for prior hits
2141 if( idx != 0 ) {
2142 Node *hit = _igvn.hash_find_insert(phi);
2143 if( hit == NULL ) {
2144 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2145 } else { // or
2146 // Remove the new phi from the graph and use the hit
2147 _igvn.remove_dead_node(phi);
2148 phi = hit; // Use existing phi
2149 }
2150 set_ctrl(phi, prev);
2151 }
2152 // Make 'use' use the Phi instead of the old loop body exit value
2153 _igvn.replace_input_of(use, idx, phi);
2154 if( use->_idx >= new_counter ) { // If updating new phis
2155 // Not needed for correctness, but prevents a weak assert
2156 // in AddPNode from tripping (when we end up with different
2157 // base & derived Phis that will become the same after
2158 // IGVN does CSE).
2159 Node *hit = _igvn.hash_find_insert(use);
2160 if( hit ) // Go ahead and re-hash for hits.
2161 _igvn.replace_node( use, hit );
2162 }
2163
2164 // If 'use' was in the loop-exit block, it now needs to be sunk
2165 // below the post-loop merge point.
2166 sink_use( use, prev );
2167 }
2168 }
2169 }
2170
2171 static void collect_nodes_in_outer_loop_not_reachable_from_sfpt(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop,
2172 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase,
2173 bool check_old_new) {
2174 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2175 Node* u = n->fast_out(j);
2176 assert(check_old_new || old_new[u->_idx] == NULL, "shouldn't have been cloned");
2177 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == NULL)) {
2178 Node* c = phase->get_ctrl(u);
2179 IdealLoopTree* u_loop = phase->get_loop(c);
2180 assert(!loop->is_member(u_loop) || !loop->_body.contains(u), "can be in outer loop or out of both loops only");
2181 if (!loop->is_member(u_loop)) {
2182 if (outer_loop->is_member(u_loop)) {
2183 wq.push(u);
2184 } else {
2185 // nodes pinned with control in the outer loop but not referenced from the safepoint must be moved out of
2186 // the outer loop too
2187 Node* u_c = u->in(0);
2188 if (u_c != NULL) {
2189 IdealLoopTree* u_c_loop = phase->get_loop(u_c);
2190 if (outer_loop->is_member(u_c_loop) && !loop->is_member(u_c_loop)) {
2191 wq.push(u);
2192 }
2193 }
2194 }
2195 }
2196 }
2197 }
2198 }
2199
2200 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2201 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2202 Node_List& extra_data_nodes) {
2203 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2204 CountedLoopNode* cl = head->as_CountedLoop();
2205 Node* l = cl->outer_loop();
2206 Node* tail = cl->outer_loop_tail();
2207 IfNode* le = cl->outer_loop_end();
2208 Node* sfpt = cl->outer_safepoint();
2209 CountedLoopEndNode* cle = cl->loopexit();
2210 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2211 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2212 Node* cle_out = cle->proj_out(false);
2213
2214 Node* new_sfpt = NULL;
2215 Node* new_cle_out = cle_out->clone();
2216 old_new.map(cle_out->_idx, new_cle_out);
2217 if (mode == CloneIncludesStripMined) {
2218 // clone outer loop body
2219 Node* new_l = l->clone();
2220 Node* new_tail = tail->clone();
2221 IfNode* new_le = le->clone()->as_If();
2222 new_sfpt = sfpt->clone();
2223
2224 set_loop(new_l, outer_loop->_parent);
2225 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2226 set_loop(new_cle_out, outer_loop->_parent);
2227 set_idom(new_cle_out, new_cle, dd);
2228 set_loop(new_sfpt, outer_loop->_parent);
2229 set_idom(new_sfpt, new_cle_out, dd);
2230 set_loop(new_le, outer_loop->_parent);
2231 set_idom(new_le, new_sfpt, dd);
2232 set_loop(new_tail, outer_loop->_parent);
2233 set_idom(new_tail, new_le, dd);
2234 set_idom(new_cl, new_l, dd);
2235
2236 old_new.map(l->_idx, new_l);
2237 old_new.map(tail->_idx, new_tail);
2238 old_new.map(le->_idx, new_le);
2239 old_new.map(sfpt->_idx, new_sfpt);
2240
2241 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2242 new_l->set_req(0, new_l);
2243 new_tail->set_req(0, new_le);
2244 new_le->set_req(0, new_sfpt);
2245 new_sfpt->set_req(0, new_cle_out);
2246 new_cle_out->set_req(0, new_cle);
2247 new_cl->set_req(LoopNode::EntryControl, new_l);
2248
2249 _igvn.register_new_node_with_optimizer(new_l);
2250 _igvn.register_new_node_with_optimizer(new_tail);
2251 _igvn.register_new_node_with_optimizer(new_le);
2252 } else {
2253 Node *newhead = old_new[loop->_head->_idx];
2254 newhead->as_Loop()->clear_strip_mined();
2255 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2256 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2257 }
2258 // Look at data node that were assigned a control in the outer
2259 // loop: they are kept in the outer loop by the safepoint so start
2260 // from the safepoint node's inputs.
2261 IdealLoopTree* outer_loop = get_loop(l);
2262 Node_Stack stack(2);
2263 stack.push(sfpt, 1);
2264 uint new_counter = C->unique();
2265 while (stack.size() > 0) {
2266 Node* n = stack.node();
2267 uint i = stack.index();
2268 while (i < n->req() &&
2269 (n->in(i) == NULL ||
2270 !has_ctrl(n->in(i)) ||
2271 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2272 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2273 i++;
2274 }
2275 if (i < n->req()) {
2276 stack.set_index(i+1);
2277 stack.push(n->in(i), 0);
2278 } else {
2279 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2280 Node* m = n == sfpt ? new_sfpt : n->clone();
2281 if (m != NULL) {
2282 for (uint i = 0; i < n->req(); i++) {
2283 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) {
2284 m->set_req(i, old_new[m->in(i)->_idx]);
2285 }
2286 }
2287 } else {
2288 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2289 }
2290 if (n != sfpt) {
2291 extra_data_nodes.push(n);
2292 _igvn.register_new_node_with_optimizer(m);
2293 assert(get_ctrl(n) == cle_out, "what other control?");
2294 set_ctrl(m, new_cle_out);
2295 old_new.map(n->_idx, m);
2296 }
2297 stack.pop();
2298 }
2299 }
2300 if (mode == CloneIncludesStripMined) {
2301 _igvn.register_new_node_with_optimizer(new_sfpt);
2302 _igvn.register_new_node_with_optimizer(new_cle_out);
2303 }
2304 // Some other transformation may have pessimistically assigned some
2305 // data nodes to the outer loop. Set their control so they are out
2306 // of the outer loop.
2307 ResourceMark rm;
2308 Unique_Node_List wq;
2309 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2310 Node* old = extra_data_nodes.at(i);
2311 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2312 }
2313
2314 for (uint i = 0; i < loop->_body.size(); i++) {
2315 Node* old = loop->_body.at(i);
2316 collect_nodes_in_outer_loop_not_reachable_from_sfpt(old, loop, outer_loop, old_new, wq, this, true);
2317 }
2318
2319 Node* inner_out = sfpt->in(0);
2320 if (inner_out->outcnt() > 1) {
2321 collect_nodes_in_outer_loop_not_reachable_from_sfpt(inner_out, loop, outer_loop, old_new, wq, this, true);
2322 }
2323
2324 Node* new_ctrl = cl->outer_loop_exit();
2325 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest");
2326 for (uint i = 0; i < wq.size(); i++) {
2327 Node* n = wq.at(i);
2328 set_ctrl(n, new_ctrl);
2329 if (n->in(0) != NULL) {
2330 _igvn.replace_input_of(n, 0, new_ctrl);
2331 }
2332 collect_nodes_in_outer_loop_not_reachable_from_sfpt(n, loop, outer_loop, old_new, wq, this, false);
2333 }
2334 } else {
2335 Node *newhead = old_new[loop->_head->_idx];
2336 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2337 }
2338 }
2339
2340 //------------------------------clone_loop-------------------------------------
2341 //
2342 // C L O N E A L O O P B O D Y
2343 //
2344 // This is the basic building block of the loop optimizations. It clones an
2345 // entire loop body. It makes an old_new loop body mapping; with this mapping
2346 // you can find the new-loop equivalent to an old-loop node. All new-loop
2347 // nodes are exactly equal to their old-loop counterparts, all edges are the
2348 // same. All exits from the old-loop now have a RegionNode that merges the
2349 // equivalent new-loop path. This is true even for the normal "loop-exit"
2350 // condition. All uses of loop-invariant old-loop values now come from (one
2351 // or more) Phis that merge their new-loop equivalents.
2352 //
2353 // This operation leaves the graph in an illegal state: there are two valid
2354 // control edges coming from the loop pre-header to both loop bodies. I'll
2355 // definitely have to hack the graph after running this transform.
2356 //
2357 // From this building block I will further edit edges to perform loop peeling
2358 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2359 //
2360 // Parameter side_by_size_idom:
2361 // When side_by_size_idom is NULL, the dominator tree is constructed for
2362 // the clone loop to dominate the original. Used in construction of
2363 // pre-main-post loop sequence.
2364 // When nonnull, the clone and original are side-by-side, both are
2365 // dominated by the side_by_side_idom node. Used in construction of
2366 // unswitched loops.
2367 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2368 CloneLoopMode mode, Node* side_by_side_idom) {
2369
2370 LoopNode* head = loop->_head->as_Loop();
2371 head->verify_strip_mined(1);
2372
2373 if (C->do_vector_loop() && PrintOpto) {
2374 const char* mname = C->method()->name()->as_quoted_ascii();
2375 if (mname != NULL) {
2376 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2377 }
2378 }
2379
2380 CloneMap& cm = C->clone_map();
2381 if (C->do_vector_loop()) {
2382 cm.set_clone_idx(cm.max_gen()+1);
2383 #ifndef PRODUCT
2384 if (PrintOpto) {
2385 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2386 loop->dump_head();
2387 }
2388 #endif
2389 }
2390
2391 // Step 1: Clone the loop body. Make the old->new mapping.
2392 clone_loop_body(loop->_body, old_new, &cm);
2393
2394 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2395
2396 // Step 2: Fix the edges in the new body. If the old input is outside the
2397 // loop use it. If the old input is INside the loop, use the corresponding
2398 // new node instead.
2399 fix_body_edges(loop->_body, loop, old_new, dd, outer_loop->_parent, false);
2400
2401 Node_List extra_data_nodes; // data nodes in the outer strip mined loop
2402 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2403
2404 // Step 3: Now fix control uses. Loop varying control uses have already
2405 // been fixed up (as part of all input edges in Step 2). Loop invariant
2406 // control uses must be either an IfFalse or an IfTrue. Make a merge
2407 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2408 // refer to this.
2409 Node_List worklist;
2410 uint new_counter = C->unique();
2411 fix_ctrl_uses(loop->_body, loop, old_new, mode, side_by_side_idom, &cm, worklist);
2412
2413 // Step 4: If loop-invariant use is not control, it must be dominated by a
2414 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2415 // there if needed. Make a Phi there merging old and new used values.
2416 Node_List *split_if_set = NULL;
2417 Node_List *split_bool_set = NULL;
2418 Node_List *split_cex_set = NULL;
2419 fix_data_uses(loop->_body, loop, mode, outer_loop, new_counter, old_new, worklist, split_if_set, split_bool_set, split_cex_set);
2420
2421 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2422 Node* old = extra_data_nodes.at(i);
2423 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2424 split_bool_set, split_cex_set, worklist, new_counter,
2425 mode);
2426 }
2427
2428 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2429 // the loop uses a condition set in the loop. The original IF probably
2430 // takes control from one or more OLD Regions (which in turn get from NEW
2431 // Regions). In any case, there will be a set of Phis for each merge point
2432 // from the IF up to where the original BOOL def exists the loop.
2433 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
2434
2435 }
2436
2437 void PhaseIdealLoop::finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set) {
2438 if (split_if_set) {
2439 while (split_if_set->size()) {
2440 Node *iff = split_if_set->pop();
2441 uint input = iff->Opcode() == Op_AllocateArray ? AllocateNode::ValidLengthTest : 1;
2442 if (iff->in(input)->is_Phi()) {
2443 Node *b = clone_iff(iff->in(input)->as_Phi());
2444 _igvn.replace_input_of(iff, input, b);
2445 }
2446 }
2447 }
2448 if (split_bool_set) {
2449 while (split_bool_set->size()) {
2450 Node *b = split_bool_set->pop();
2451 Node *phi = b->in(1);
2452 assert(phi->is_Phi(), "");
2453 CmpNode *cmp = clone_bool((PhiNode*) phi);
2454 _igvn.replace_input_of(b, 1, cmp);
2455 }
2456 }
2457 if (split_cex_set) {
2458 while (split_cex_set->size()) {
2459 Node *b = split_cex_set->pop();
2460 assert(b->in(0)->is_Region(), "");
2461 assert(b->in(1)->is_Phi(), "");
2462 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2463 split_up(b, b->in(0), NULL);
2464 }
2465 }
2466 }
2467
2468 void PhaseIdealLoop::fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop,
2469 uint new_counter, Node_List &old_new, Node_List &worklist, Node_List*& split_if_set,
2470 Node_List*& split_bool_set, Node_List*& split_cex_set) {
2471 for(uint i = 0; i < body.size(); i++ ) {
2472 Node* old = body.at(i);
2473 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2474 split_bool_set, split_cex_set, worklist, new_counter,
2475 mode);
2476 }
2477 }
2478
2479 void PhaseIdealLoop::fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode,
2480 Node* side_by_side_idom, CloneMap* cm, Node_List &worklist) {
2481 LoopNode* head = loop->_head->as_Loop();
2482 for(uint i = 0; i < body.size(); i++ ) {
2483 Node* old = body.at(i);
2484 if( !old->is_CFG() ) continue;
2485
2486 // Copy uses to a worklist, so I can munge the def-use info
2487 // with impunity.
2488 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) {
2489 worklist.push(old->fast_out(j));
2490 }
2491
2492 while (worklist.size()) { // Visit all uses
2493 Node *use = worklist.pop();
2494 if (!has_node(use)) continue; // Ignore dead nodes
2495 IdealLoopTree *use_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use );
2496 if (!loop->is_member(use_loop) && use->is_CFG()) {
2497 // Both OLD and USE are CFG nodes here.
2498 assert(use->is_Proj(), "" );
2499 Node* nnn = old_new[old->_idx];
2500
2501 Node* newuse = NULL;
2502 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2503 CountedLoopNode* cl = head->as_CountedLoop();
2504 CountedLoopEndNode* cle = cl->loopexit();
2505 Node* cle_out = cle->proj_out_or_null(false);
2506 if (use == cle_out) {
2507 IfNode* le = cl->outer_loop_end();
2508 use = le->proj_out(false);
2509 use_loop = get_loop(use);
2510 if (mode == CloneIncludesStripMined) {
2511 nnn = old_new[le->_idx];
2512 } else {
2513 newuse = old_new[cle_out->_idx];
2514 }
2515 }
2516 }
2517 if (newuse == NULL) {
2518 newuse = use->clone();
2519 }
2520
2521 // Clone the loop exit control projection
2522 if (C->do_vector_loop() && cm != NULL) {
2523 cm->verify_insert_and_clone(use, newuse, cm->clone_idx());
2524 }
2525 newuse->set_req(0,nnn);
2526 _igvn.register_new_node_with_optimizer(newuse);
2527 set_loop(newuse, use_loop);
2528 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2529
2530 // We need a Region to merge the exit from the peeled body and the
2531 // exit from the old loop body.
2532 RegionNode *r = new RegionNode(3);
2533 // Map the old use to the new merge point
2534 old_new.map( use->_idx, r );
2535 uint dd_r = MIN2(dom_depth(newuse), dom_depth(use));
2536 assert(dd_r >= dom_depth(dom_lca(newuse, use)), "" );
2537
2538 // The original user of 'use' uses 'r' instead.
2539 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2540 Node* useuse = use->last_out(l);
2541 _igvn.rehash_node_delayed(useuse);
2542 uint uses_found = 0;
2543 if (useuse->in(0) == use) {
2544 useuse->set_req(0, r);
2545 uses_found++;
2546 if (useuse->is_CFG()) {
2547 // This is not a dom_depth > dd_r because when new
2548 // control flow is constructed by a loop opt, a node and
2549 // its dominator can end up at the same dom_depth
2550 assert(dom_depth(useuse) >= dd_r, "");
2551 set_idom(useuse, r, dom_depth(useuse));
2552 }
2553 }
2554 for (uint k = 1; k < useuse->req(); k++) {
2555 if( useuse->in(k) == use ) {
2556 useuse->set_req(k, r);
2557 uses_found++;
2558 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2559 // This is not a dom_depth > dd_r because when new
2560 // control flow is constructed by a loop opt, a node
2561 // and its dominator can end up at the same dom_depth
2562 assert(dom_depth(useuse) >= dd_r , "");
2563 set_idom(useuse, r, dom_depth(useuse));
2564 }
2565 }
2566 }
2567 l -= uses_found; // we deleted 1 or more copies of this edge
2568 }
2569
2570 // Now finish up 'r'
2571 r->set_req(1, newuse);
2572 r->set_req(2, use);
2573 _igvn.register_new_node_with_optimizer(r);
2574 set_loop(r, use_loop);
2575 set_idom(r, (side_by_side_idom == NULL) ? newuse->in(0) : side_by_side_idom, dd_r);
2576 } // End of if a loop-exit test
2577 }
2578 }
2579 }
2580
2581 void PhaseIdealLoop::fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd,
2582 IdealLoopTree* parent, bool partial) {
2583 for(uint i = 0; i < body.size(); i++ ) {
2584 Node *old = body.at(i);
2585 Node *nnn = old_new[old->_idx];
2586 // Fix CFG/Loop controlling the new node
2587 if (has_ctrl(old)) {
2588 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2589 } else {
2590 set_loop(nnn, parent);
2591 if (old->outcnt() > 0) {
2592 Node* dom = idom(old);
2593 if (old_new[dom->_idx] != NULL) {
2594 dom = old_new[dom->_idx];
2595 set_idom(nnn, dom, dd );
2596 }
2597 }
2598 }
2599 // Correct edges to the new node
2600 for (uint j = 0; j < nnn->req(); j++) {
2601 Node *n = nnn->in(j);
2602 if (n != NULL) {
2603 IdealLoopTree *old_in_loop = get_loop(has_ctrl(n) ? get_ctrl(n) : n);
2604 if (loop->is_member(old_in_loop)) {
2605 if (old_new[n->_idx] != NULL) {
2606 nnn->set_req(j, old_new[n->_idx]);
2607 } else {
2608 assert(!body.contains(n), "");
2609 assert(partial, "node not cloned");
2610 }
2611 }
2612 }
2613 }
2614 _igvn.hash_find_insert(nnn);
2615 }
2616 }
2617
2618 void PhaseIdealLoop::clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm) {
2619 for (uint i = 0; i < body.size(); i++) {
2620 Node* old = body.at(i);
2621 Node* nnn = old->clone();
2622 old_new.map(old->_idx, nnn);
2623 if (old->is_reduction()) {
2624 // Reduction flag is not copied by default. Copy it here when cloning the entire loop body.
2625 nnn->add_flag(Node::Flag_is_reduction);
2626 }
2627 if (C->do_vector_loop() && cm != NULL) {
2628 cm->verify_insert_and_clone(old, nnn, cm->clone_idx());
2629 }
2630 _igvn.register_new_node_with_optimizer(nnn);
2631 }
2632 }
2633
2634
2635 //---------------------- stride_of_possible_iv -------------------------------------
2636 // Looks for an iff/bool/comp with one operand of the compare
2637 // being a cycle involving an add and a phi,
2638 // with an optional truncation (left-shift followed by a right-shift)
2639 // of the add. Returns zero if not an iv.
2640 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2641 Node* trunc1 = NULL;
2642 Node* trunc2 = NULL;
2643 const TypeInteger* ttype = NULL;
2644 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) {
2645 return 0;
2646 }
2647 BoolNode* bl = iff->in(1)->as_Bool();
2648 Node* cmp = bl->in(1);
2649 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2650 return 0;
2651 }
2652 // Must have an invariant operand
2653 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2654 return 0;
2655 }
2656 Node* add2 = NULL;
2657 Node* cmp1 = cmp->in(1);
2658 if (cmp1->is_Phi()) {
2659 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2660 Node* phi = cmp1;
2661 for (uint i = 1; i < phi->req(); i++) {
2662 Node* in = phi->in(i);
2663 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2664 &trunc1, &trunc2, &ttype, T_INT);
2665 if (add && add->in(1) == phi) {
2666 add2 = add->in(2);
2667 break;
2668 }
2669 }
2670 } else {
2671 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2672 Node* addtrunc = cmp1;
2673 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2674 &trunc1, &trunc2, &ttype, T_INT);
2675 if (add && add->in(1)->is_Phi()) {
2676 Node* phi = add->in(1);
2677 for (uint i = 1; i < phi->req(); i++) {
2678 if (phi->in(i) == addtrunc) {
2679 add2 = add->in(2);
2680 break;
2681 }
2682 }
2683 }
2684 }
2685 if (add2 != NULL) {
2686 const TypeInt* add2t = _igvn.type(add2)->is_int();
2687 if (add2t->is_con()) {
2688 return add2t->get_con();
2689 }
2690 }
2691 return 0;
2692 }
2693
2694
2695 //---------------------- stay_in_loop -------------------------------------
2696 // Return the (unique) control output node that's in the loop (if it exists.)
2697 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2698 Node* unique = NULL;
2699 if (!n) return NULL;
2700 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2701 Node* use = n->fast_out(i);
2702 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2703 if (unique != NULL) {
2704 return NULL;
2705 }
2706 unique = use;
2707 }
2708 }
2709 return unique;
2710 }
2711
2712 //------------------------------ register_node -------------------------------------
2713 // Utility to register node "n" with PhaseIdealLoop
2714 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) {
2715 _igvn.register_new_node_with_optimizer(n);
2716 loop->_body.push(n);
2717 if (n->is_CFG()) {
2718 set_loop(n, loop);
2719 set_idom(n, pred, ddepth);
2720 } else {
2721 set_ctrl(n, pred);
2722 }
2723 }
2724
2725 //------------------------------ proj_clone -------------------------------------
2726 // Utility to create an if-projection
2727 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2728 ProjNode* c = p->clone()->as_Proj();
2729 c->set_req(0, iff);
2730 return c;
2731 }
2732
2733 //------------------------------ short_circuit_if -------------------------------------
2734 // Force the iff control output to be the live_proj
2735 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2736 guarantee(live_proj != NULL, "null projection");
2737 int proj_con = live_proj->_con;
2738 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2739 Node *con = _igvn.intcon(proj_con);
2740 set_ctrl(con, C->root());
2741 if (iff) {
2742 iff->set_req(1, con);
2743 }
2744 return con;
2745 }
2746
2747 //------------------------------ insert_if_before_proj -------------------------------------
2748 // Insert a new if before an if projection (* - new node)
2749 //
2750 // before
2751 // if(test)
2752 // / \
2753 // v v
2754 // other-proj proj (arg)
2755 //
2756 // after
2757 // if(test)
2758 // / \
2759 // / v
2760 // | * proj-clone
2761 // v |
2762 // other-proj v
2763 // * new_if(relop(cmp[IU](left,right)))
2764 // / \
2765 // v v
2766 // * new-proj proj
2767 // (returned)
2768 //
2769 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2770 IfNode* iff = proj->in(0)->as_If();
2771 IdealLoopTree *loop = get_loop(proj);
2772 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2773 int ddepth = dom_depth(proj);
2774
2775 _igvn.rehash_node_delayed(iff);
2776 _igvn.rehash_node_delayed(proj);
2777
2778 proj->set_req(0, NULL); // temporary disconnect
2779 ProjNode* proj2 = proj_clone(proj, iff);
2780 register_node(proj2, loop, iff, ddepth);
2781
2782 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2783 register_node(cmp, loop, proj2, ddepth);
2784
2785 BoolNode* bol = new BoolNode(cmp, relop);
2786 register_node(bol, loop, proj2, ddepth);
2787
2788 int opcode = iff->Opcode();
2789 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2790 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
2791 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
2792 register_node(new_if, loop, proj2, ddepth);
2793
2794 proj->set_req(0, new_if); // reattach
2795 set_idom(proj, new_if, ddepth);
2796
2797 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2798 guarantee(new_exit != NULL, "null exit node");
2799 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2800
2801 return new_exit;
2802 }
2803
2804 //------------------------------ insert_region_before_proj -------------------------------------
2805 // Insert a region before an if projection (* - new node)
2806 //
2807 // before
2808 // if(test)
2809 // / |
2810 // v |
2811 // proj v
2812 // other-proj
2813 //
2814 // after
2815 // if(test)
2816 // / |
2817 // v |
2818 // * proj-clone v
2819 // | other-proj
2820 // v
2821 // * new-region
2822 // |
2823 // v
2824 // * dum_if
2825 // / \
2826 // v \
2827 // * dum-proj v
2828 // proj
2829 //
2830 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2831 IfNode* iff = proj->in(0)->as_If();
2832 IdealLoopTree *loop = get_loop(proj);
2833 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2834 int ddepth = dom_depth(proj);
2835
2836 _igvn.rehash_node_delayed(iff);
2837 _igvn.rehash_node_delayed(proj);
2838
2839 proj->set_req(0, NULL); // temporary disconnect
2840 ProjNode* proj2 = proj_clone(proj, iff);
2841 register_node(proj2, loop, iff, ddepth);
2842
2843 RegionNode* reg = new RegionNode(2);
2844 reg->set_req(1, proj2);
2845 register_node(reg, loop, iff, ddepth);
2846
2847 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt);
2848 register_node(dum_if, loop, reg, ddepth);
2849
2850 proj->set_req(0, dum_if); // reattach
2851 set_idom(proj, dum_if, ddepth);
2852
2853 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
2854 register_node(dum_proj, loop, dum_if, ddepth);
2855
2856 return reg;
2857 }
2858
2859 //------------------------------ insert_cmpi_loop_exit -------------------------------------
2860 // Clone a signed compare loop exit from an unsigned compare and
2861 // insert it before the unsigned cmp on the stay-in-loop path.
2862 // All new nodes inserted in the dominator tree between the original
2863 // if and it's projections. The original if test is replaced with
2864 // a constant to force the stay-in-loop path.
2865 //
2866 // This is done to make sure that the original if and it's projections
2867 // still dominate the same set of control nodes, that the ctrl() relation
2868 // from data nodes to them is preserved, and that their loop nesting is
2869 // preserved.
2870 //
2871 // before
2872 // if(i <u limit) unsigned compare loop exit
2873 // / |
2874 // v v
2875 // exit-proj stay-in-loop-proj
2876 //
2877 // after
2878 // if(stay-in-loop-const) original if
2879 // / |
2880 // / v
2881 // / if(i < limit) new signed test
2882 // / / |
2883 // / / v
2884 // / / if(i <u limit) new cloned unsigned test
2885 // / / / |
2886 // v v v |
2887 // region |
2888 // | |
2889 // dum-if |
2890 // / | |
2891 // ether | |
2892 // v v
2893 // exit-proj stay-in-loop-proj
2894 //
2895 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
2896 const bool Signed = true;
2897 const bool Unsigned = false;
2898
2899 BoolNode* bol = if_cmpu->in(1)->as_Bool();
2900 if (bol->_test._test != BoolTest::lt) return NULL;
2901 CmpNode* cmpu = bol->in(1)->as_Cmp();
2902 if (cmpu->Opcode() != Op_CmpU) return NULL;
2903 int stride = stride_of_possible_iv(if_cmpu);
2904 if (stride == 0) return NULL;
2905
2906 Node* lp_proj = stay_in_loop(if_cmpu, loop);
2907 guarantee(lp_proj != NULL, "null loop node");
2908
2909 ProjNode* lp_continue = lp_proj->as_Proj();
2910 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
2911 if (!lp_exit->is_IfFalse()) {
2912 // The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit).
2913 // We therefore can't add a single exit condition.
2914 return NULL;
2915 }
2916 // The loop exit condition is !(i <u limit) ==> (i < 0 || i >= limit).
2917 // Split out the exit condition (i < 0) for stride < 0 or (i >= limit) for stride > 0.
2918 Node* limit = NULL;
2919 if (stride > 0) {
2920 limit = cmpu->in(2);
2921 } else {
2922 limit = _igvn.makecon(TypeInt::ZERO);
2923 set_ctrl(limit, C->root());
2924 }
2925 // Create a new region on the exit path
2926 RegionNode* reg = insert_region_before_proj(lp_exit);
2927 guarantee(reg != NULL, "null region node");
2928
2929 // Clone the if-cmpu-true-false using a signed compare
2930 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
2931 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
2932 reg->add_req(cmpi_exit);
2933
2934 // Clone the if-cmpu-true-false
2935 BoolTest::mask rel_u = bol->_test._test;
2936 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
2937 reg->add_req(cmpu_exit);
2938
2939 // Force original if to stay in loop.
2940 short_circuit_if(if_cmpu, lp_continue);
2941
2942 return cmpi_exit->in(0)->as_If();
2943 }
2944
2945 //------------------------------ remove_cmpi_loop_exit -------------------------------------
2946 // Remove a previously inserted signed compare loop exit.
2947 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
2948 Node* lp_proj = stay_in_loop(if_cmp, loop);
2949 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
2950 stay_in_loop(lp_proj, loop)->is_If() &&
2951 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
2952 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
2953 set_ctrl(con, C->root());
2954 if_cmp->set_req(1, con);
2955 }
2956
2957 //------------------------------ scheduled_nodelist -------------------------------------
2958 // Create a post order schedule of nodes that are in the
2959 // "member" set. The list is returned in "sched".
2960 // The first node in "sched" is the loop head, followed by
2961 // nodes which have no inputs in the "member" set, and then
2962 // followed by the nodes that have an immediate input dependence
2963 // on a node in "sched".
2964 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
2965
2966 assert(member.test(loop->_head->_idx), "loop head must be in member set");
2967 VectorSet visited;
2968 Node_Stack nstack(loop->_body.size());
2969
2970 Node* n = loop->_head; // top of stack is cached in "n"
2971 uint idx = 0;
2972 visited.set(n->_idx);
2973
2974 // Initially push all with no inputs from within member set
2975 for(uint i = 0; i < loop->_body.size(); i++ ) {
2976 Node *elt = loop->_body.at(i);
2977 if (member.test(elt->_idx)) {
2978 bool found = false;
2979 for (uint j = 0; j < elt->req(); j++) {
2980 Node* def = elt->in(j);
2981 if (def && member.test(def->_idx) && def != elt) {
2982 found = true;
2983 break;
2984 }
2985 }
2986 if (!found && elt != loop->_head) {
2987 nstack.push(n, idx);
2988 n = elt;
2989 assert(!visited.test(n->_idx), "not seen yet");
2990 visited.set(n->_idx);
2991 }
2992 }
2993 }
2994
2995 // traverse out's that are in the member set
2996 while (true) {
2997 if (idx < n->outcnt()) {
2998 Node* use = n->raw_out(idx);
2999 idx++;
3000 if (!visited.test_set(use->_idx)) {
3001 if (member.test(use->_idx)) {
3002 nstack.push(n, idx);
3003 n = use;
3004 idx = 0;
3005 }
3006 }
3007 } else {
3008 // All outputs processed
3009 sched.push(n);
3010 if (nstack.is_empty()) break;
3011 n = nstack.node();
3012 idx = nstack.index();
3013 nstack.pop();
3014 }
3015 }
3016 }
3017
3018
3019 //------------------------------ has_use_in_set -------------------------------------
3020 // Has a use in the vector set
3021 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
3022 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3023 Node* use = n->fast_out(j);
3024 if (vset.test(use->_idx)) {
3025 return true;
3026 }
3027 }
3028 return false;
3029 }
3030
3031
3032 //------------------------------ has_use_internal_to_set -------------------------------------
3033 // Has use internal to the vector set (ie. not in a phi at the loop head)
3034 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
3035 Node* head = loop->_head;
3036 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3037 Node* use = n->fast_out(j);
3038 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
3039 return true;
3040 }
3041 }
3042 return false;
3043 }
3044
3045
3046 //------------------------------ clone_for_use_outside_loop -------------------------------------
3047 // clone "n" for uses that are outside of loop
3048 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
3049 int cloned = 0;
3050 assert(worklist.size() == 0, "should be empty");
3051 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3052 Node* use = n->fast_out(j);
3053 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
3054 worklist.push(use);
3055 }
3056 }
3057
3058 if (C->check_node_count(worklist.size() + NodeLimitFudgeFactor,
3059 "Too many clones required in clone_for_use_outside_loop in partial peeling")) {
3060 return -1;
3061 }
3062
3063 while( worklist.size() ) {
3064 Node *use = worklist.pop();
3065 if (!has_node(use) || use->in(0) == C->top()) continue;
3066 uint j;
3067 for (j = 0; j < use->req(); j++) {
3068 if (use->in(j) == n) break;
3069 }
3070 assert(j < use->req(), "must be there");
3071
3072 // clone "n" and insert it between the inputs of "n" and the use outside the loop
3073 Node* n_clone = n->clone();
3074 _igvn.replace_input_of(use, j, n_clone);
3075 cloned++;
3076 Node* use_c;
3077 if (!use->is_Phi()) {
3078 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
3079 } else {
3080 // Use in a phi is considered a use in the associated predecessor block
3081 use_c = use->in(0)->in(j);
3082 }
3083 set_ctrl(n_clone, use_c);
3084 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
3085 get_loop(use_c)->_body.push(n_clone);
3086 _igvn.register_new_node_with_optimizer(n_clone);
3087 #ifndef PRODUCT
3088 if (TracePartialPeeling) {
3089 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
3090 }
3091 #endif
3092 }
3093 return cloned;
3094 }
3095
3096
3097 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
3098 // clone "n" for special uses that are in the not_peeled region.
3099 // If these def-uses occur in separate blocks, the code generator
3100 // marks the method as not compilable. For example, if a "BoolNode"
3101 // is in a different basic block than the "IfNode" that uses it, then
3102 // the compilation is aborted in the code generator.
3103 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
3104 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
3105 if (n->is_Phi() || n->is_Load()) {
3106 return;
3107 }
3108 assert(worklist.size() == 0, "should be empty");
3109 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3110 Node* use = n->fast_out(j);
3111 if ( not_peel.test(use->_idx) &&
3112 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
3113 use->in(1) == n) {
3114 worklist.push(use);
3115 }
3116 }
3117 if (worklist.size() > 0) {
3118 // clone "n" and insert it between inputs of "n" and the use
3119 Node* n_clone = n->clone();
3120 loop->_body.push(n_clone);
3121 _igvn.register_new_node_with_optimizer(n_clone);
3122 set_ctrl(n_clone, get_ctrl(n));
3123 sink_list.push(n_clone);
3124 not_peel.set(n_clone->_idx);
3125 #ifndef PRODUCT
3126 if (TracePartialPeeling) {
3127 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
3128 }
3129 #endif
3130 while( worklist.size() ) {
3131 Node *use = worklist.pop();
3132 _igvn.rehash_node_delayed(use);
3133 for (uint j = 1; j < use->req(); j++) {
3134 if (use->in(j) == n) {
3135 use->set_req(j, n_clone);
3136 }
3137 }
3138 }
3139 }
3140 }
3141
3142
3143 //------------------------------ insert_phi_for_loop -------------------------------------
3144 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
3145 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
3146 Node *phi = PhiNode::make(lp, back_edge_val);
3147 phi->set_req(LoopNode::EntryControl, lp_entry_val);
3148 // Use existing phi if it already exists
3149 Node *hit = _igvn.hash_find_insert(phi);
3150 if( hit == NULL ) {
3151 _igvn.register_new_node_with_optimizer(phi);
3152 set_ctrl(phi, lp);
3153 } else {
3154 // Remove the new phi from the graph and use the hit
3155 _igvn.remove_dead_node(phi);
3156 phi = hit;
3157 }
3158 _igvn.replace_input_of(use, idx, phi);
3159 }
3160
3161 #ifdef ASSERT
3162 //------------------------------ is_valid_loop_partition -------------------------------------
3163 // Validate the loop partition sets: peel and not_peel
3164 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
3165 VectorSet& not_peel ) {
3166 uint i;
3167 // Check that peel_list entries are in the peel set
3168 for (i = 0; i < peel_list.size(); i++) {
3169 if (!peel.test(peel_list.at(i)->_idx)) {
3170 return false;
3171 }
3172 }
3173 // Check at loop members are in one of peel set or not_peel set
3174 for (i = 0; i < loop->_body.size(); i++ ) {
3175 Node *def = loop->_body.at(i);
3176 uint di = def->_idx;
3177 // Check that peel set elements are in peel_list
3178 if (peel.test(di)) {
3179 if (not_peel.test(di)) {
3180 return false;
3181 }
3182 // Must be in peel_list also
3183 bool found = false;
3184 for (uint j = 0; j < peel_list.size(); j++) {
3185 if (peel_list.at(j)->_idx == di) {
3186 found = true;
3187 break;
3188 }
3189 }
3190 if (!found) {
3191 return false;
3192 }
3193 } else if (not_peel.test(di)) {
3194 if (peel.test(di)) {
3195 return false;
3196 }
3197 } else {
3198 return false;
3199 }
3200 }
3201 return true;
3202 }
3203
3204 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
3205 // Ensure a use outside of loop is of the right form
3206 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
3207 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3208 return (use->is_Phi() &&
3209 use_c->is_Region() && use_c->req() == 3 &&
3210 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
3211 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
3212 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
3213 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
3214 }
3215
3216 //------------------------------ is_valid_clone_loop_form -------------------------------------
3217 // Ensure that all uses outside of loop are of the right form
3218 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
3219 uint orig_exit_idx, uint clone_exit_idx) {
3220 uint len = peel_list.size();
3221 for (uint i = 0; i < len; i++) {
3222 Node *def = peel_list.at(i);
3223
3224 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3225 Node *use = def->fast_out(j);
3226 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3227 if (!loop->is_member(get_loop(use_c))) {
3228 // use is not in the loop, check for correct structure
3229 if (use->in(0) == def) {
3230 // Okay
3231 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
3232 return false;
3233 }
3234 }
3235 }
3236 }
3237 return true;
3238 }
3239 #endif
3240
3241 //------------------------------ partial_peel -------------------------------------
3242 // Partially peel (aka loop rotation) the top portion of a loop (called
3243 // the peel section below) by cloning it and placing one copy just before
3244 // the new loop head and the other copy at the bottom of the new loop.
3245 //
3246 // before after where it came from
3247 //
3248 // stmt1 stmt1
3249 // loop: stmt2 clone
3250 // stmt2 if condA goto exitA clone
3251 // if condA goto exitA new_loop: new
3252 // stmt3 stmt3 clone
3253 // if !condB goto loop if condB goto exitB clone
3254 // exitB: stmt2 orig
3255 // stmt4 if !condA goto new_loop orig
3256 // exitA: goto exitA
3257 // exitB:
3258 // stmt4
3259 // exitA:
3260 //
3261 // Step 1: find the cut point: an exit test on probable
3262 // induction variable.
3263 // Step 2: schedule (with cloning) operations in the peel
3264 // section that can be executed after the cut into
3265 // the section that is not peeled. This may need
3266 // to clone operations into exit blocks. For
3267 // instance, a reference to A[i] in the not-peel
3268 // section and a reference to B[i] in an exit block
3269 // may cause a left-shift of i by 2 to be placed
3270 // in the peel block. This step will clone the left
3271 // shift into the exit block and sink the left shift
3272 // from the peel to the not-peel section.
3273 // Step 3: clone the loop, retarget the control, and insert
3274 // phis for values that are live across the new loop
3275 // head. This is very dependent on the graph structure
3276 // from clone_loop. It creates region nodes for
3277 // exit control and associated phi nodes for values
3278 // flow out of the loop through that exit. The region
3279 // node is dominated by the clone's control projection.
3280 // So the clone's peel section is placed before the
3281 // new loop head, and the clone's not-peel section is
3282 // forms the top part of the new loop. The original
3283 // peel section forms the tail of the new loop.
3284 // Step 4: update the dominator tree and recompute the
3285 // dominator depth.
3286 //
3287 // orig
3288 //
3289 // stmt1
3290 // |
3291 // v
3292 // loop predicate
3293 // |
3294 // v
3295 // loop<----+
3296 // | |
3297 // stmt2 |
3298 // | |
3299 // v |
3300 // ifA |
3301 // / | |
3302 // v v |
3303 // false true ^ <-- last_peel
3304 // / | |
3305 // / ===|==cut |
3306 // / stmt3 | <-- first_not_peel
3307 // / | |
3308 // | v |
3309 // v ifB |
3310 // exitA: / \ |
3311 // / \ |
3312 // v v |
3313 // false true |
3314 // / \ |
3315 // / ----+
3316 // |
3317 // v
3318 // exitB:
3319 // stmt4
3320 //
3321 //
3322 // after clone loop
3323 //
3324 // stmt1
3325 // |
3326 // v
3327 // loop predicate
3328 // / \
3329 // clone / \ orig
3330 // / \
3331 // / \
3332 // v v
3333 // +---->loop loop<----+
3334 // | | | |
3335 // | stmt2 stmt2 |
3336 // | | | |
3337 // | v v |
3338 // | ifA ifA |
3339 // | | \ / | |
3340 // | v v v v |
3341 // ^ true false false true ^ <-- last_peel
3342 // | | ^ \ / | |
3343 // | cut==|== \ \ / ===|==cut |
3344 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3345 // | | dom | | | |
3346 // | v \ 1v v2 v |
3347 // | ifB regionA ifB |
3348 // | / \ | / \ |
3349 // | / \ v / \ |
3350 // | v v exitA: v v |
3351 // | true false false true |
3352 // | / ^ \ / \ |
3353 // +---- \ \ / ----+
3354 // dom \ /
3355 // \ 1v v2
3356 // regionB
3357 // |
3358 // v
3359 // exitB:
3360 // stmt4
3361 //
3362 //
3363 // after partial peel
3364 //
3365 // stmt1
3366 // |
3367 // v
3368 // loop predicate
3369 // /
3370 // clone / orig
3371 // / TOP
3372 // / \
3373 // v v
3374 // TOP->loop loop----+
3375 // | | |
3376 // stmt2 stmt2 |
3377 // | | |
3378 // v v |
3379 // ifA ifA |
3380 // | \ / | |
3381 // v v v v |
3382 // true false false true | <-- last_peel
3383 // | ^ \ / +------|---+
3384 // +->newloop \ \ / === ==cut | |
3385 // | stmt3 \ \ / TOP | |
3386 // | | dom | | stmt3 | | <-- first_not_peel
3387 // | v \ 1v v2 v | |
3388 // | ifB regionA ifB ^ v
3389 // | / \ | / \ | |
3390 // | / \ v / \ | |
3391 // | v v exitA: v v | |
3392 // | true false false true | |
3393 // | / ^ \ / \ | |
3394 // | | \ \ / v | |
3395 // | | dom \ / TOP | |
3396 // | | \ 1v v2 | |
3397 // ^ v regionB | |
3398 // | | | | |
3399 // | | v ^ v
3400 // | | exitB: | |
3401 // | | stmt4 | |
3402 // | +------------>-----------------+ |
3403 // | |
3404 // +-----------------<---------------------+
3405 //
3406 //
3407 // final graph
3408 //
3409 // stmt1
3410 // |
3411 // v
3412 // loop predicate
3413 // |
3414 // v
3415 // stmt2 clone
3416 // |
3417 // v
3418 // ........> ifA clone
3419 // : / |
3420 // dom / |
3421 // : v v
3422 // : false true
3423 // : | |
3424 // : | v
3425 // : | newloop<-----+
3426 // : | | |
3427 // : | stmt3 clone |
3428 // : | | |
3429 // : | v |
3430 // : | ifB |
3431 // : | / \ |
3432 // : | v v |
3433 // : | false true |
3434 // : | | | |
3435 // : | v stmt2 |
3436 // : | exitB: | |
3437 // : | stmt4 v |
3438 // : | ifA orig |
3439 // : | / \ |
3440 // : | / \ |
3441 // : | v v |
3442 // : | false true |
3443 // : | / \ |
3444 // : v v -----+
3445 // RegionA
3446 // |
3447 // v
3448 // exitA
3449 //
3450 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3451
3452 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3453 if (!loop->_head->is_Loop()) {
3454 return false;
3455 }
3456 LoopNode *head = loop->_head->as_Loop();
3457
3458 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3459 return false;
3460 }
3461
3462 // Check for complex exit control
3463 for (uint ii = 0; ii < loop->_body.size(); ii++) {
3464 Node *n = loop->_body.at(ii);
3465 int opc = n->Opcode();
3466 if (n->is_Call() ||
3467 opc == Op_Catch ||
3468 opc == Op_CatchProj ||
3469 opc == Op_Jump ||
3470 opc == Op_JumpProj) {
3471 #ifndef PRODUCT
3472 if (TracePartialPeeling) {
3473 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3474 }
3475 #endif
3476 return false;
3477 }
3478 }
3479
3480 int dd = dom_depth(head);
3481
3482 // Step 1: find cut point
3483
3484 // Walk up dominators to loop head looking for first loop exit
3485 // which is executed on every path thru loop.
3486 IfNode *peel_if = NULL;
3487 IfNode *peel_if_cmpu = NULL;
3488
3489 Node *iff = loop->tail();
3490 while (iff != head) {
3491 if (iff->is_If()) {
3492 Node *ctrl = get_ctrl(iff->in(1));
3493 if (ctrl->is_top()) return false; // Dead test on live IF.
3494 // If loop-varying exit-test, check for induction variable
3495 if (loop->is_member(get_loop(ctrl)) &&
3496 loop->is_loop_exit(iff) &&
3497 is_possible_iv_test(iff)) {
3498 Node* cmp = iff->in(1)->in(1);
3499 if (cmp->Opcode() == Op_CmpI) {
3500 peel_if = iff->as_If();
3501 } else {
3502 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3503 peel_if_cmpu = iff->as_If();
3504 }
3505 }
3506 }
3507 iff = idom(iff);
3508 }
3509
3510 // Prefer signed compare over unsigned compare.
3511 IfNode* new_peel_if = NULL;
3512 if (peel_if == NULL) {
3513 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) {
3514 return false; // No peel point found
3515 }
3516 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3517 if (new_peel_if == NULL) {
3518 return false; // No peel point found
3519 }
3520 peel_if = new_peel_if;
3521 }
3522 Node* last_peel = stay_in_loop(peel_if, loop);
3523 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3524 if (first_not_peeled == NULL || first_not_peeled == head) {
3525 return false;
3526 }
3527
3528 #ifndef PRODUCT
3529 if (TraceLoopOpts) {
3530 tty->print("PartialPeel ");
3531 loop->dump_head();
3532 }
3533
3534 if (TracePartialPeeling) {
3535 tty->print_cr("before partial peel one iteration");
3536 Node_List wl;
3537 Node* t = head->in(2);
3538 while (true) {
3539 wl.push(t);
3540 if (t == head) break;
3541 t = idom(t);
3542 }
3543 while (wl.size() > 0) {
3544 Node* tt = wl.pop();
3545 tt->dump();
3546 if (tt == last_peel) tty->print_cr("-- cut --");
3547 }
3548 }
3549 #endif
3550 VectorSet peel;
3551 VectorSet not_peel;
3552 Node_List peel_list;
3553 Node_List worklist;
3554 Node_List sink_list;
3555
3556 uint estimate = loop->est_loop_clone_sz(1);
3557 if (exceeding_node_budget(estimate)) {
3558 return false;
3559 }
3560
3561 // Set of cfg nodes to peel are those that are executable from
3562 // the head through last_peel.
3563 assert(worklist.size() == 0, "should be empty");
3564 worklist.push(head);
3565 peel.set(head->_idx);
3566 while (worklist.size() > 0) {
3567 Node *n = worklist.pop();
3568 if (n != last_peel) {
3569 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3570 Node* use = n->fast_out(j);
3571 if (use->is_CFG() &&
3572 loop->is_member(get_loop(use)) &&
3573 !peel.test_set(use->_idx)) {
3574 worklist.push(use);
3575 }
3576 }
3577 }
3578 }
3579
3580 // Set of non-cfg nodes to peel are those that are control
3581 // dependent on the cfg nodes.
3582 for (uint i = 0; i < loop->_body.size(); i++) {
3583 Node *n = loop->_body.at(i);
3584 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3585 if (peel.test(n_c->_idx)) {
3586 peel.set(n->_idx);
3587 } else {
3588 not_peel.set(n->_idx);
3589 }
3590 }
3591
3592 // Step 2: move operations from the peeled section down into the
3593 // not-peeled section
3594
3595 // Get a post order schedule of nodes in the peel region
3596 // Result in right-most operand.
3597 scheduled_nodelist(loop, peel, peel_list);
3598
3599 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3600
3601 // For future check for too many new phis
3602 uint old_phi_cnt = 0;
3603 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3604 Node* use = head->fast_out(j);
3605 if (use->is_Phi()) old_phi_cnt++;
3606 }
3607
3608 #ifndef PRODUCT
3609 if (TracePartialPeeling) {
3610 tty->print_cr("\npeeled list");
3611 }
3612 #endif
3613
3614 // Evacuate nodes in peel region into the not_peeled region if possible
3615 bool too_many_clones = false;
3616 uint new_phi_cnt = 0;
3617 uint cloned_for_outside_use = 0;
3618 for (uint i = 0; i < peel_list.size();) {
3619 Node* n = peel_list.at(i);
3620 #ifndef PRODUCT
3621 if (TracePartialPeeling) n->dump();
3622 #endif
3623 bool incr = true;
3624 if (!n->is_CFG()) {
3625 if (has_use_in_set(n, not_peel)) {
3626 // If not used internal to the peeled region,
3627 // move "n" from peeled to not_peeled region.
3628 if (!has_use_internal_to_set(n, peel, loop)) {
3629 // if not pinned and not a load (which maybe anti-dependent on a store)
3630 // and not a CMove (Matcher expects only bool->cmove).
3631 if (n->in(0) == NULL && !n->is_Load() && !n->is_CMove()) {
3632 int new_clones = clone_for_use_outside_loop(loop, n, worklist);
3633 if (new_clones == -1) {
3634 too_many_clones = true;
3635 break;
3636 }
3637 cloned_for_outside_use += new_clones;
3638 sink_list.push(n);
3639 peel.remove(n->_idx);
3640 not_peel.set(n->_idx);
3641 peel_list.remove(i);
3642 incr = false;
3643 #ifndef PRODUCT
3644 if (TracePartialPeeling) {
3645 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3646 n->_idx, get_ctrl(n)->_idx);
3647 }
3648 #endif
3649 }
3650 } else {
3651 // Otherwise check for special def-use cases that span
3652 // the peel/not_peel boundary such as bool->if
3653 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist);
3654 new_phi_cnt++;
3655 }
3656 }
3657 }
3658 if (incr) i++;
3659 }
3660
3661 estimate += cloned_for_outside_use + new_phi_cnt;
3662 bool exceed_node_budget = !may_require_nodes(estimate);
3663 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta;
3664
3665 if (too_many_clones || exceed_node_budget || exceed_phi_limit) {
3666 #ifndef PRODUCT
3667 if (TracePartialPeeling && exceed_phi_limit) {
3668 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3669 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F');
3670 }
3671 #endif
3672 if (new_peel_if != NULL) {
3673 remove_cmpi_loop_exit(new_peel_if, loop);
3674 }
3675 // Inhibit more partial peeling on this loop
3676 assert(!head->is_partial_peel_loop(), "not partial peeled");
3677 head->mark_partial_peel_failed();
3678 if (cloned_for_outside_use > 0) {
3679 // Terminate this round of loop opts because
3680 // the graph outside this loop was changed.
3681 C->set_major_progress();
3682 return true;
3683 }
3684 return false;
3685 }
3686
3687 // Step 3: clone loop, retarget control, and insert new phis
3688
3689 // Create new loop head for new phis and to hang
3690 // the nodes being moved (sinked) from the peel region.
3691 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3692 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3693 _igvn.register_new_node_with_optimizer(new_head);
3694 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3695 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3696 set_loop(new_head, loop);
3697 loop->_body.push(new_head);
3698 not_peel.set(new_head->_idx);
3699 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3700 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3701
3702 while (sink_list.size() > 0) {
3703 Node* n = sink_list.pop();
3704 set_ctrl(n, new_head);
3705 }
3706
3707 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3708
3709 clone_loop(loop, old_new, dd, IgnoreStripMined);
3710
3711 const uint clone_exit_idx = 1;
3712 const uint orig_exit_idx = 2;
3713 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop");
3714
3715 Node* head_clone = old_new[head->_idx];
3716 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3717 Node* orig_tail_clone = head_clone->in(2);
3718
3719 // Add phi if "def" node is in peel set and "use" is not
3720
3721 for (uint i = 0; i < peel_list.size(); i++) {
3722 Node *def = peel_list.at(i);
3723 if (!def->is_CFG()) {
3724 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3725 Node *use = def->fast_out(j);
3726 if (has_node(use) && use->in(0) != C->top() &&
3727 (!peel.test(use->_idx) ||
3728 (use->is_Phi() && use->in(0) == head)) ) {
3729 worklist.push(use);
3730 }
3731 }
3732 while( worklist.size() ) {
3733 Node *use = worklist.pop();
3734 for (uint j = 1; j < use->req(); j++) {
3735 Node* n = use->in(j);
3736 if (n == def) {
3737
3738 // "def" is in peel set, "use" is not in peel set
3739 // or "use" is in the entry boundary (a phi) of the peel set
3740
3741 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3742
3743 if ( loop->is_member(get_loop( use_c )) ) {
3744 // use is in loop
3745 if (old_new[use->_idx] != NULL) { // null for dead code
3746 Node* use_clone = old_new[use->_idx];
3747 _igvn.replace_input_of(use, j, C->top());
3748 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3749 }
3750 } else {
3751 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3752 // use is not in the loop, check if the live range includes the cut
3753 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3754 if (not_peel.test(lp_if->_idx)) {
3755 assert(j == orig_exit_idx, "use from original loop");
3756 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3757 }
3758 }
3759 }
3760 }
3761 }
3762 }
3763 }
3764
3765 // Step 3b: retarget control
3766
3767 // Redirect control to the new loop head if a cloned node in
3768 // the not_peeled region has control that points into the peeled region.
3769 // This necessary because the cloned peeled region will be outside
3770 // the loop.
3771 // from to
3772 // cloned-peeled <---+
3773 // new_head_clone: | <--+
3774 // cloned-not_peeled in(0) in(0)
3775 // orig-peeled
3776
3777 for (uint i = 0; i < loop->_body.size(); i++) {
3778 Node *n = loop->_body.at(i);
3779 if (!n->is_CFG() && n->in(0) != NULL &&
3780 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
3781 Node* n_clone = old_new[n->_idx];
3782 _igvn.replace_input_of(n_clone, 0, new_head_clone);
3783 }
3784 }
3785
3786 // Backedge of the surviving new_head (the clone) is original last_peel
3787 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
3788
3789 // Cut first node in original not_peel set
3790 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
3791 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
3792 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
3793
3794 // Copy head_clone back-branch info to original head
3795 // and remove original head's loop entry and
3796 // clone head's back-branch
3797 _igvn.rehash_node_delayed(head); // Multiple edge updates
3798 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
3799 head->set_req(LoopNode::LoopBackControl, C->top());
3800 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
3801
3802 // Similarly modify the phis
3803 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
3804 Node* use = head->fast_out(k);
3805 if (use->is_Phi() && use->outcnt() > 0) {
3806 Node* use_clone = old_new[use->_idx];
3807 _igvn.rehash_node_delayed(use); // Multiple edge updates
3808 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
3809 use->set_req(LoopNode::LoopBackControl, C->top());
3810 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
3811 }
3812 }
3813
3814 // Step 4: update dominator tree and dominator depth
3815
3816 set_idom(head, orig_tail_clone, dd);
3817 recompute_dom_depth();
3818
3819 // Inhibit more partial peeling on this loop
3820 new_head_clone->set_partial_peel_loop();
3821 C->set_major_progress();
3822 loop->record_for_igvn();
3823
3824 #ifndef PRODUCT
3825 if (TracePartialPeeling) {
3826 tty->print_cr("\nafter partial peel one iteration");
3827 Node_List wl;
3828 Node* t = last_peel;
3829 while (true) {
3830 wl.push(t);
3831 if (t == head_clone) break;
3832 t = idom(t);
3833 }
3834 while (wl.size() > 0) {
3835 Node* tt = wl.pop();
3836 if (tt == head) tty->print_cr("orig head");
3837 else if (tt == new_head_clone) tty->print_cr("new head");
3838 else if (tt == head_clone) tty->print_cr("clone head");
3839 tt->dump();
3840 }
3841 }
3842 #endif
3843 return true;
3844 }
3845
3846 // Transform:
3847 //
3848 // loop<-----------------+
3849 // | |
3850 // stmt1 stmt2 .. stmtn |
3851 // | | | |
3852 // \ | / |
3853 // v v v |
3854 // region |
3855 // | |
3856 // shared_stmt |
3857 // | |
3858 // v |
3859 // if |
3860 // / \ |
3861 // | -----------+
3862 // v
3863 //
3864 // into:
3865 //
3866 // loop<-------------------+
3867 // | |
3868 // v |
3869 // +->loop |
3870 // | | |
3871 // | stmt1 stmt2 .. stmtn |
3872 // | | | | |
3873 // | | \ / |
3874 // | | v v |
3875 // | | region1 |
3876 // | | | |
3877 // | shared_stmt shared_stmt |
3878 // | | | |
3879 // | v v |
3880 // | if if |
3881 // | /\ / \ |
3882 // +-- | | -------+
3883 // \ /
3884 // v v
3885 // region2
3886 //
3887 // (region2 is shown to merge mirrored projections of the loop exit
3888 // ifs to make the diagram clearer but they really merge the same
3889 // projection)
3890 //
3891 // Conditions for this transformation to trigger:
3892 // - the path through stmt1 is frequent enough
3893 // - the inner loop will be turned into a counted loop after transformation
3894 bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new) {
3895 if (!DuplicateBackedge) {
3896 return false;
3897 }
3898 assert(!loop->_head->is_CountedLoop() || StressDuplicateBackedge, "Non-counted loop only");
3899 if (!loop->_head->is_Loop()) {
3900 return false;
3901 }
3902
3903 uint estimate = loop->est_loop_clone_sz(1);
3904 if (exceeding_node_budget(estimate)) {
3905 return false;
3906 }
3907
3908 LoopNode *head = loop->_head->as_Loop();
3909
3910 Node* region = NULL;
3911 IfNode* exit_test = NULL;
3912 uint inner;
3913 float f;
3914 if (StressDuplicateBackedge) {
3915 if (head->is_strip_mined()) {
3916 return false;
3917 }
3918 Node* c = head->in(LoopNode::LoopBackControl);
3919
3920 while (c != head) {
3921 if (c->is_Region()) {
3922 region = c;
3923 }
3924 c = idom(c);
3925 }
3926
3927 if (region == NULL) {
3928 return false;
3929 }
3930
3931 inner = 1;
3932 } else {
3933 // Is the shape of the loop that of a counted loop...
3934 Node* back_control = loop_exit_control(head, loop);
3935 if (back_control == NULL) {
3936 return false;
3937 }
3938
3939 BoolTest::mask bt = BoolTest::illegal;
3940 float cl_prob = 0;
3941 Node* incr = NULL;
3942 Node* limit = NULL;
3943 Node* cmp = loop_exit_test(back_control, loop, incr, limit, bt, cl_prob);
3944 if (cmp == NULL || cmp->Opcode() != Op_CmpI) {
3945 return false;
3946 }
3947
3948 // With an extra phi for the candidate iv?
3949 // Or the region node is the loop head
3950 if (!incr->is_Phi() || incr->in(0) == head) {
3951 return false;
3952 }
3953
3954 PathFrequency pf(head, this);
3955 region = incr->in(0);
3956
3957 // Go over all paths for the extra phi's region and see if that
3958 // path is frequent enough and would match the expected iv shape
3959 // if the extra phi is removed
3960 inner = 0;
3961 for (uint i = 1; i < incr->req(); ++i) {
3962 Node* in = incr->in(i);
3963 Node* trunc1 = NULL;
3964 Node* trunc2 = NULL;
3965 const TypeInteger* iv_trunc_t = NULL;
3966 Node* orig_in = in;
3967 if (!(in = CountedLoopNode::match_incr_with_optional_truncation(in, &trunc1, &trunc2, &iv_trunc_t, T_INT))) {
3968 continue;
3969 }
3970 assert(in->Opcode() == Op_AddI, "wrong increment code");
3971 Node* xphi = NULL;
3972 Node* stride = loop_iv_stride(in, loop, xphi);
3973
3974 if (stride == NULL) {
3975 continue;
3976 }
3977
3978 PhiNode* phi = loop_iv_phi(xphi, NULL, head, loop);
3979 if (phi == NULL ||
3980 (trunc1 == NULL && phi->in(LoopNode::LoopBackControl) != incr) ||
3981 (trunc1 != NULL && phi->in(LoopNode::LoopBackControl) != trunc1)) {
3982 return false;
3983 }
3984
3985 f = pf.to(region->in(i));
3986 if (f > 0.5) {
3987 inner = i;
3988 break;
3989 }
3990 }
3991
3992 if (inner == 0) {
3993 return false;
3994 }
3995
3996 exit_test = back_control->in(0)->as_If();
3997 }
3998
3999 if (idom(region)->is_Catch()) {
4000 return false;
4001 }
4002
4003 // Collect all control nodes that need to be cloned (shared_stmt in the diagram)
4004 Unique_Node_List wq;
4005 wq.push(head->in(LoopNode::LoopBackControl));
4006 for (uint i = 0; i < wq.size(); i++) {
4007 Node* c = wq.at(i);
4008 assert(get_loop(c) == loop, "not in the right loop?");
4009 if (c->is_Region()) {
4010 if (c != region) {
4011 for (uint j = 1; j < c->req(); ++j) {
4012 wq.push(c->in(j));
4013 }
4014 }
4015 } else {
4016 wq.push(c->in(0));
4017 }
4018 assert(!is_dominator(c, region) || c == region, "shouldn't go above region");
4019 }
4020
4021 Node* region_dom = idom(region);
4022
4023 // Can't do the transformation if this would cause a membar pair to
4024 // be split
4025 for (uint i = 0; i < wq.size(); i++) {
4026 Node* c = wq.at(i);
4027 if (c->is_MemBar() && (c->as_MemBar()->trailing_store() || c->as_MemBar()->trailing_load_store())) {
4028 assert(c->as_MemBar()->leading_membar()->trailing_membar() == c, "bad membar pair");
4029 if (!wq.member(c->as_MemBar()->leading_membar())) {
4030 return false;
4031 }
4032 }
4033 }
4034
4035 // Collect data nodes that need to be clones as well
4036 int dd = dom_depth(head);
4037
4038 for (uint i = 0; i < loop->_body.size(); ++i) {
4039 Node* n = loop->_body.at(i);
4040 if (has_ctrl(n)) {
4041 Node* c = get_ctrl(n);
4042 if (wq.member(c)) {
4043 wq.push(n);
4044 }
4045 } else {
4046 set_idom(n, idom(n), dd);
4047 }
4048 }
4049
4050 // clone shared_stmt
4051 clone_loop_body(wq, old_new, NULL);
4052
4053 Node* region_clone = old_new[region->_idx];
4054 region_clone->set_req(inner, C->top());
4055 set_idom(region, region->in(inner), dd);
4056
4057 // Prepare the outer loop
4058 Node* outer_head = new LoopNode(head->in(LoopNode::EntryControl), old_new[head->in(LoopNode::LoopBackControl)->_idx]);
4059 register_control(outer_head, loop->_parent, outer_head->in(LoopNode::EntryControl));
4060 _igvn.replace_input_of(head, LoopNode::EntryControl, outer_head);
4061 set_idom(head, outer_head, dd);
4062
4063 fix_body_edges(wq, loop, old_new, dd, loop->_parent, true);
4064
4065 // Make one of the shared_stmt copies only reachable from stmt1, the
4066 // other only from stmt2..stmtn.
4067 Node* dom = NULL;
4068 for (uint i = 1; i < region->req(); ++i) {
4069 if (i != inner) {
4070 _igvn.replace_input_of(region, i, C->top());
4071 }
4072 Node* in = region_clone->in(i);
4073 if (in->is_top()) {
4074 continue;
4075 }
4076 if (dom == NULL) {
4077 dom = in;
4078 } else {
4079 dom = dom_lca(dom, in);
4080 }
4081 }
4082
4083 set_idom(region_clone, dom, dd);
4084
4085 // Set up the outer loop
4086 for (uint i = 0; i < head->outcnt(); i++) {
4087 Node* u = head->raw_out(i);
4088 if (u->is_Phi()) {
4089 Node* outer_phi = u->clone();
4090 outer_phi->set_req(0, outer_head);
4091 Node* backedge = old_new[u->in(LoopNode::LoopBackControl)->_idx];
4092 if (backedge == NULL) {
4093 backedge = u->in(LoopNode::LoopBackControl);
4094 }
4095 outer_phi->set_req(LoopNode::LoopBackControl, backedge);
4096 register_new_node(outer_phi, outer_head);
4097 _igvn.replace_input_of(u, LoopNode::EntryControl, outer_phi);
4098 }
4099 }
4100
4101 // create control and data nodes for out of loop uses (including region2)
4102 Node_List worklist;
4103 uint new_counter = C->unique();
4104 fix_ctrl_uses(wq, loop, old_new, ControlAroundStripMined, outer_head, NULL, worklist);
4105
4106 Node_List *split_if_set = NULL;
4107 Node_List *split_bool_set = NULL;
4108 Node_List *split_cex_set = NULL;
4109 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);
4110
4111 finish_clone_loop(split_if_set, split_bool_set, split_cex_set);
4112
4113 if (exit_test != NULL) {
4114 float cnt = exit_test->_fcnt;
4115 if (cnt != COUNT_UNKNOWN) {
4116 exit_test->_fcnt = cnt * f;
4117 old_new[exit_test->_idx]->as_If()->_fcnt = cnt * (1 - f);
4118 }
4119 }
4120
4121 C->set_major_progress();
4122
4123 return true;
4124 }