1 /*
2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "opto/addnode.hpp"
29 #include "opto/callnode.hpp"
30 #include "opto/castnode.hpp"
31 #include "opto/connode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/divnode.hpp"
34 #include "opto/loopnode.hpp"
35 #include "opto/matcher.hpp"
36 #include "opto/mulnode.hpp"
37 #include "opto/movenode.hpp"
38 #include "opto/opaquenode.hpp"
39 #include "opto/rootnode.hpp"
40 #include "opto/subnode.hpp"
41
42 //=============================================================================
43 //------------------------------split_thru_phi---------------------------------
44 // Split Node 'n' through merge point if there is enough win.
45 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) {
46 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
47 // ConvI2L may have type information on it which is unsafe to push up
48 // so disable this for now
49 return NULL;
50 }
51
52 // Splitting range check CastIIs through a loop induction Phi can
53 // cause new Phis to be created that are left unrelated to the loop
54 // induction Phi and prevent optimizations (vectorization)
55 if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() &&
56 region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) {
57 return NULL;
58 }
59
60 int wins = 0;
61 assert(!n->is_CFG(), "");
62 assert(region->is_Region(), "");
63
64 const Type* type = n->bottom_type();
65 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr();
66 Node *phi;
67 if (t_oop != NULL && t_oop->is_known_instance_field()) {
68 int iid = t_oop->instance_id();
69 int index = C->get_alias_index(t_oop);
70 int offset = t_oop->offset();
71 phi = new PhiNode(region, type, NULL, iid, index, offset);
72 } else {
73 phi = PhiNode::make_blank(region, n);
74 }
75 uint old_unique = C->unique();
76 for (uint i = 1; i < region->req(); i++) {
77 Node *x;
78 Node* the_clone = NULL;
79 if (region->in(i) == C->top()) {
80 x = C->top(); // Dead path? Use a dead data op
81 } else {
82 x = n->clone(); // Else clone up the data op
83 the_clone = x; // Remember for possible deletion.
84 // Alter data node to use pre-phi inputs
85 if (n->in(0) == region)
86 x->set_req( 0, region->in(i) );
87 for (uint j = 1; j < n->req(); j++) {
88 Node *in = n->in(j);
89 if (in->is_Phi() && in->in(0) == region)
90 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone
91 }
92 }
93 // Check for a 'win' on some paths
94 const Type *t = x->Value(&_igvn);
95
96 bool singleton = t->singleton();
97
98 // A TOP singleton indicates that there are no possible values incoming
99 // along a particular edge. In most cases, this is OK, and the Phi will
100 // be eliminated later in an Ideal call. However, we can't allow this to
101 // happen if the singleton occurs on loop entry, as the elimination of
102 // the PhiNode may cause the resulting node to migrate back to a previous
103 // loop iteration.
104 if (singleton && t == Type::TOP) {
105 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
106 // irreducible loop may not be indicated by an affirmative is_Loop());
107 // therefore, the only top we can split thru a phi is on a backedge of
108 // a loop.
109 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
110 }
111
112 if (singleton) {
113 wins++;
114 x = ((PhaseGVN&)_igvn).makecon(t);
115 } else {
116 // We now call Identity to try to simplify the cloned node.
117 // Note that some Identity methods call phase->type(this).
118 // Make sure that the type array is big enough for
119 // our new node, even though we may throw the node away.
120 // (Note: This tweaking with igvn only works because x is a new node.)
121 _igvn.set_type(x, t);
122 // If x is a TypeNode, capture any more-precise type permanently into Node
123 // otherwise it will be not updated during igvn->transform since
124 // igvn->type(x) is set to x->Value() already.
125 x->raise_bottom_type(t);
126 Node *y = x->Identity(&_igvn);
127 if (y != x) {
128 wins++;
129 x = y;
130 } else {
131 y = _igvn.hash_find(x);
132 if (y) {
133 wins++;
134 x = y;
135 } else {
136 // Else x is a new node we are keeping
137 // We do not need register_new_node_with_optimizer
138 // because set_type has already been called.
139 _igvn._worklist.push(x);
140 }
141 }
142 }
143 if (x != the_clone && the_clone != NULL)
144 _igvn.remove_dead_node(the_clone);
145 phi->set_req( i, x );
146 }
147 // Too few wins?
148 if (wins <= policy) {
149 _igvn.remove_dead_node(phi);
150 return NULL;
151 }
152
153 // Record Phi
154 register_new_node( phi, region );
155
156 for (uint i2 = 1; i2 < phi->req(); i2++) {
157 Node *x = phi->in(i2);
158 // If we commoned up the cloned 'x' with another existing Node,
159 // the existing Node picks up a new use. We need to make the
160 // existing Node occur higher up so it dominates its uses.
161 Node *old_ctrl;
162 IdealLoopTree *old_loop;
163
164 if (x->is_Con()) {
165 // Constant's control is always root.
166 set_ctrl(x, C->root());
167 continue;
168 }
169 // The occasional new node
170 if (x->_idx >= old_unique) { // Found a new, unplaced node?
171 old_ctrl = NULL;
172 old_loop = NULL; // Not in any prior loop
173 } else {
174 old_ctrl = get_ctrl(x);
175 old_loop = get_loop(old_ctrl); // Get prior loop
176 }
177 // New late point must dominate new use
178 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
179 if (new_ctrl == old_ctrl) // Nothing is changed
180 continue;
181
182 IdealLoopTree *new_loop = get_loop(new_ctrl);
183
184 // Don't move x into a loop if its uses are
185 // outside of loop. Otherwise x will be cloned
186 // for each use outside of this loop.
187 IdealLoopTree *use_loop = get_loop(region);
188 if (!new_loop->is_member(use_loop) &&
189 (old_loop == NULL || !new_loop->is_member(old_loop))) {
190 // Take early control, later control will be recalculated
191 // during next iteration of loop optimizations.
192 new_ctrl = get_early_ctrl(x);
193 new_loop = get_loop(new_ctrl);
194 }
195 // Set new location
196 set_ctrl(x, new_ctrl);
197 // If changing loop bodies, see if we need to collect into new body
198 if (old_loop != new_loop) {
199 if (old_loop && !old_loop->_child)
200 old_loop->_body.yank(x);
201 if (!new_loop->_child)
202 new_loop->_body.push(x); // Collect body info
203 }
204 }
205
206 return phi;
207 }
208
209 //------------------------------dominated_by------------------------------------
210 // Replace the dominated test with an obvious true or false. Place it on the
211 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
212 // live path up to the dominating control.
213 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) {
214 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
215
216 // prevdom is the dominating projection of the dominating test.
217 assert( iff->is_If(), "" );
218 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added");
219 int pop = prevdom->Opcode();
220 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
221 if (flip) {
222 if (pop == Op_IfTrue)
223 pop = Op_IfFalse;
224 else
225 pop = Op_IfTrue;
226 }
227 // 'con' is set to true or false to kill the dominated test.
228 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
229 set_ctrl(con, C->root()); // Constant gets a new use
230 // Hack the dominated test
231 _igvn.replace_input_of(iff, 1, con);
232
233 // If I dont have a reachable TRUE and FALSE path following the IfNode then
234 // I can assume this path reaches an infinite loop. In this case it's not
235 // important to optimize the data Nodes - either the whole compilation will
236 // be tossed or this path (and all data Nodes) will go dead.
237 if (iff->outcnt() != 2) return;
238
239 // Make control-dependent data Nodes on the live path (path that will remain
240 // once the dominated IF is removed) become control-dependent on the
241 // dominating projection.
242 Node* dp = iff->as_If()->proj_out_or_null(pop == Op_IfTrue);
243
244 // Loop predicates may have depending checks which should not
245 // be skipped. For example, range check predicate has two checks
246 // for lower and upper bounds.
247 if (dp == NULL)
248 return;
249
250 ProjNode* dp_proj = dp->as_Proj();
251 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj();
252 if (exclude_loop_predicate &&
253 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL ||
254 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) {
255 // If this is a range check (IfNode::is_range_check), do not
256 // reorder because Compile::allow_range_check_smearing might have
257 // changed the check.
258 return; // Let IGVN transformation change control dependence.
259 }
260
261 IdealLoopTree *old_loop = get_loop(dp);
262
263 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
264 Node* cd = dp->fast_out(i); // Control-dependent node
265 if (cd->depends_only_on_test()) {
266 assert(cd->in(0) == dp, "");
267 _igvn.replace_input_of(cd, 0, prevdom);
268 set_early_ctrl(cd);
269 IdealLoopTree *new_loop = get_loop(get_ctrl(cd));
270 if (old_loop != new_loop) {
271 if (!old_loop->_child) old_loop->_body.yank(cd);
272 if (!new_loop->_child) new_loop->_body.push(cd);
273 }
274 --i;
275 --imax;
276 }
277 }
278 }
279
280 //------------------------------has_local_phi_input----------------------------
281 // Return TRUE if 'n' has Phi inputs from its local block and no other
282 // block-local inputs (all non-local-phi inputs come from earlier blocks)
283 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
284 Node *n_ctrl = get_ctrl(n);
285 // See if some inputs come from a Phi in this block, or from before
286 // this block.
287 uint i;
288 for( i = 1; i < n->req(); i++ ) {
289 Node *phi = n->in(i);
290 if( phi->is_Phi() && phi->in(0) == n_ctrl )
291 break;
292 }
293 if( i >= n->req() )
294 return NULL; // No Phi inputs; nowhere to clone thru
295
296 // Check for inputs created between 'n' and the Phi input. These
297 // must split as well; they have already been given the chance
298 // (courtesy of a post-order visit) and since they did not we must
299 // recover the 'cost' of splitting them by being very profitable
300 // when splitting 'n'. Since this is unlikely we simply give up.
301 for( i = 1; i < n->req(); i++ ) {
302 Node *m = n->in(i);
303 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
304 // We allow the special case of AddP's with no local inputs.
305 // This allows us to split-up address expressions.
306 if (m->is_AddP() &&
307 get_ctrl(m->in(2)) != n_ctrl &&
308 get_ctrl(m->in(3)) != n_ctrl) {
309 // Move the AddP up to dominating point
310 Node* c = find_non_split_ctrl(idom(n_ctrl));
311 if (c->is_OuterStripMinedLoop()) {
312 c->as_Loop()->verify_strip_mined(1);
313 c = c->in(LoopNode::EntryControl);
314 }
315 set_ctrl_and_loop(m, c);
316 continue;
317 }
318 return NULL;
319 }
320 assert(m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
321 }
322
323 return n_ctrl;
324 }
325
326 //------------------------------remix_address_expressions----------------------
327 // Rework addressing expressions to get the most loop-invariant stuff
328 // moved out. We'd like to do all associative operators, but it's especially
329 // important (common) to do address expressions.
330 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
331 if (!has_ctrl(n)) return NULL;
332 Node *n_ctrl = get_ctrl(n);
333 IdealLoopTree *n_loop = get_loop(n_ctrl);
334
335 // See if 'n' mixes loop-varying and loop-invariant inputs and
336 // itself is loop-varying.
337
338 // Only interested in binary ops (and AddP)
339 if( n->req() < 3 || n->req() > 4 ) return NULL;
340
341 Node *n1_ctrl = get_ctrl(n->in( 1));
342 Node *n2_ctrl = get_ctrl(n->in( 2));
343 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
344 IdealLoopTree *n1_loop = get_loop( n1_ctrl );
345 IdealLoopTree *n2_loop = get_loop( n2_ctrl );
346 IdealLoopTree *n3_loop = get_loop( n3_ctrl );
347
348 // Does one of my inputs spin in a tighter loop than self?
349 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) ||
350 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) ||
351 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) )
352 return NULL; // Leave well enough alone
353
354 // Is at least one of my inputs loop-invariant?
355 if( n1_loop == n_loop &&
356 n2_loop == n_loop &&
357 n3_loop == n_loop )
358 return NULL; // No loop-invariant inputs
359
360
361 int n_op = n->Opcode();
362
363 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
364 if( n_op == Op_LShiftI ) {
365 // Scale is loop invariant
366 Node *scale = n->in(2);
367 Node *scale_ctrl = get_ctrl(scale);
368 IdealLoopTree *scale_loop = get_loop(scale_ctrl );
369 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) )
370 return NULL;
371 const TypeInt *scale_t = scale->bottom_type()->isa_int();
372 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 )
373 return NULL; // Dont bother with byte/short masking
374 // Add must vary with loop (else shift would be loop-invariant)
375 Node *add = n->in(1);
376 Node *add_ctrl = get_ctrl(add);
377 IdealLoopTree *add_loop = get_loop(add_ctrl);
378 //assert( n_loop == add_loop, "" );
379 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops
380
381 // Convert I-V into I+ (0-V); same for V-I
382 if( add->Opcode() == Op_SubI &&
383 _igvn.type( add->in(1) ) != TypeInt::ZERO ) {
384 Node *zero = _igvn.intcon(0);
385 set_ctrl(zero, C->root());
386 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) );
387 register_new_node( neg, get_ctrl(add->in(2) ) );
388 add = new AddINode( add->in(1), neg );
389 register_new_node( add, add_ctrl );
390 }
391 if( add->Opcode() != Op_AddI ) return NULL;
392 // See if one add input is loop invariant
393 Node *add_var = add->in(1);
394 Node *add_var_ctrl = get_ctrl(add_var);
395 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
396 Node *add_invar = add->in(2);
397 Node *add_invar_ctrl = get_ctrl(add_invar);
398 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl );
399 if( add_var_loop == n_loop ) {
400 } else if( add_invar_loop == n_loop ) {
401 // Swap to find the invariant part
402 add_invar = add_var;
403 add_invar_ctrl = add_var_ctrl;
404 add_invar_loop = add_var_loop;
405 add_var = add->in(2);
406 Node *add_var_ctrl = get_ctrl(add_var);
407 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
408 } else // Else neither input is loop invariant
409 return NULL;
410 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) )
411 return NULL; // No invariant part of the add?
412
413 // Yes! Reshape address expression!
414 Node *inv_scale = new LShiftINode( add_invar, scale );
415 Node *inv_scale_ctrl =
416 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
417 add_invar_ctrl : scale_ctrl;
418 register_new_node( inv_scale, inv_scale_ctrl );
419 Node *var_scale = new LShiftINode( add_var, scale );
420 register_new_node( var_scale, n_ctrl );
421 Node *var_add = new AddINode( var_scale, inv_scale );
422 register_new_node( var_add, n_ctrl );
423 _igvn.replace_node( n, var_add );
424 return var_add;
425 }
426
427 // Replace (I+V) with (V+I)
428 if( n_op == Op_AddI ||
429 n_op == Op_AddL ||
430 n_op == Op_AddF ||
431 n_op == Op_AddD ||
432 n_op == Op_MulI ||
433 n_op == Op_MulL ||
434 n_op == Op_MulF ||
435 n_op == Op_MulD ) {
436 if( n2_loop == n_loop ) {
437 assert( n1_loop != n_loop, "" );
438 n->swap_edges(1, 2);
439 }
440 }
441
442 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
443 // but not if I2 is a constant.
444 if( n_op == Op_AddP ) {
445 if( n2_loop == n_loop && n3_loop != n_loop ) {
446 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) {
447 Node *n22_ctrl = get_ctrl(n->in(2)->in(2));
448 Node *n23_ctrl = get_ctrl(n->in(2)->in(3));
449 IdealLoopTree *n22loop = get_loop( n22_ctrl );
450 IdealLoopTree *n23_loop = get_loop( n23_ctrl );
451 if( n22loop != n_loop && n22loop->is_member(n_loop) &&
452 n23_loop == n_loop ) {
453 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) );
454 // Stuff new AddP in the loop preheader
455 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) );
456 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) );
457 register_new_node( add2, n_ctrl );
458 _igvn.replace_node( n, add2 );
459 return add2;
460 }
461 }
462 }
463
464 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
465 if (n2_loop != n_loop && n3_loop == n_loop) {
466 if (n->in(3)->Opcode() == Op_AddX) {
467 Node *V = n->in(3)->in(1);
468 Node *I = n->in(3)->in(2);
469 if (is_member(n_loop,get_ctrl(V))) {
470 } else {
471 Node *tmp = V; V = I; I = tmp;
472 }
473 if (!is_member(n_loop,get_ctrl(I))) {
474 Node *add1 = new AddPNode(n->in(1), n->in(2), I);
475 // Stuff new AddP in the loop preheader
476 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl));
477 Node *add2 = new AddPNode(n->in(1), add1, V);
478 register_new_node(add2, n_ctrl);
479 _igvn.replace_node(n, add2);
480 return add2;
481 }
482 }
483 }
484 }
485
486 return NULL;
487 }
488
489 //------------------------------conditional_move-------------------------------
490 // Attempt to replace a Phi with a conditional move. We have some pretty
491 // strict profitability requirements. All Phis at the merge point must
492 // be converted, so we can remove the control flow. We need to limit the
493 // number of c-moves to a small handful. All code that was in the side-arms
494 // of the CFG diamond is now speculatively executed. This code has to be
495 // "cheap enough". We are pretty much limited to CFG diamonds that merge
496 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
497 Node *PhaseIdealLoop::conditional_move( Node *region ) {
498
499 assert(region->is_Region(), "sanity check");
500 if (region->req() != 3) return NULL;
501
502 // Check for CFG diamond
503 Node *lp = region->in(1);
504 Node *rp = region->in(2);
505 if (!lp || !rp) return NULL;
506 Node *lp_c = lp->in(0);
507 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL;
508 IfNode *iff = lp_c->as_If();
509
510 // Check for ops pinned in an arm of the diamond.
511 // Can't remove the control flow in this case
512 if (lp->outcnt() > 1) return NULL;
513 if (rp->outcnt() > 1) return NULL;
514
515 IdealLoopTree* r_loop = get_loop(region);
516 assert(r_loop == get_loop(iff), "sanity");
517 // Always convert to CMOVE if all results are used only outside this loop.
518 bool used_inside_loop = (r_loop == _ltree_root);
519
520 // Check profitability
521 int cost = 0;
522 int phis = 0;
523 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
524 Node *out = region->fast_out(i);
525 if (!out->is_Phi()) continue; // Ignore other control edges, etc
526 phis++;
527 PhiNode* phi = out->as_Phi();
528 BasicType bt = phi->type()->basic_type();
529 switch (bt) {
530 case T_DOUBLE:
531 case T_FLOAT:
532 if (C->use_cmove()) {
533 continue; //TODO: maybe we want to add some cost
534 }
535 cost += Matcher::float_cmove_cost(); // Could be very expensive
536 break;
537 case T_LONG: {
538 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
539 }
540 case T_INT: // These all CMOV fine
541 case T_ADDRESS: { // (RawPtr)
542 cost++;
543 break;
544 }
545 case T_NARROWOOP: // Fall through
546 case T_OBJECT: { // Base oops are OK, but not derived oops
547 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
548 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
549 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
550 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
551 // have a Phi for the base here that we convert to a CMOVE all is well
552 // and good. But if the base is dead, we'll not make a CMOVE. Later
553 // the allocator will have to produce a base by creating a CMOVE of the
554 // relevant bases. This puts the allocator in the business of
555 // manufacturing expensive instructions, generally a bad plan.
556 // Just Say No to Conditionally-Moved Derived Pointers.
557 if (tp && tp->offset() != 0)
558 return NULL;
559 cost++;
560 break;
561 }
562 default:
563 return NULL; // In particular, can't do memory or I/O
564 }
565 // Add in cost any speculative ops
566 for (uint j = 1; j < region->req(); j++) {
567 Node *proj = region->in(j);
568 Node *inp = phi->in(j);
569 if (get_ctrl(inp) == proj) { // Found local op
570 cost++;
571 // Check for a chain of dependent ops; these will all become
572 // speculative in a CMOV.
573 for (uint k = 1; k < inp->req(); k++)
574 if (get_ctrl(inp->in(k)) == proj)
575 cost += ConditionalMoveLimit; // Too much speculative goo
576 }
577 }
578 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
579 // This will likely Split-If, a higher-payoff operation.
580 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
581 Node* use = phi->fast_out(k);
582 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
583 cost += ConditionalMoveLimit;
584 // Is there a use inside the loop?
585 // Note: check only basic types since CMoveP is pinned.
586 if (!used_inside_loop && is_java_primitive(bt)) {
587 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
588 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
589 used_inside_loop = true;
590 }
591 }
592 }
593 }//for
594 Node* bol = iff->in(1);
595 assert(bol->Opcode() == Op_Bool, "");
596 int cmp_op = bol->in(1)->Opcode();
597 // It is expensive to generate flags from a float compare.
598 // Avoid duplicated float compare.
599 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL;
600
601 float infrequent_prob = PROB_UNLIKELY_MAG(3);
602 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
603 if (used_inside_loop) {
604 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo
605
606 // BlockLayoutByFrequency optimization moves infrequent branch
607 // from hot path. No point in CMOV'ing in such case (110 is used
608 // instead of 100 to take into account not exactness of float value).
609 if (BlockLayoutByFrequency) {
610 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
611 }
612 }
613 // Check for highly predictable branch. No point in CMOV'ing if
614 // we are going to predict accurately all the time.
615 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
616 //keep going
617 } else if (iff->_prob < infrequent_prob ||
618 iff->_prob > (1.0f - infrequent_prob))
619 return NULL;
620
621 // --------------
622 // Now replace all Phis with CMOV's
623 Node *cmov_ctrl = iff->in(0);
624 uint flip = (lp->Opcode() == Op_IfTrue);
625 Node_List wq;
626 while (1) {
627 PhiNode* phi = NULL;
628 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
629 Node *out = region->fast_out(i);
630 if (out->is_Phi()) {
631 phi = out->as_Phi();
632 break;
633 }
634 }
635 if (phi == NULL) break;
636 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
637 // Move speculative ops
638 wq.push(phi);
639 while (wq.size() > 0) {
640 Node *n = wq.pop();
641 for (uint j = 1; j < n->req(); j++) {
642 Node* m = n->in(j);
643 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) {
644 #ifndef PRODUCT
645 if (PrintOpto && VerifyLoopOptimizations) {
646 tty->print(" speculate: ");
647 m->dump();
648 }
649 #endif
650 set_ctrl(m, cmov_ctrl);
651 wq.push(m);
652 }
653 }
654 }
655 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
656 register_new_node( cmov, cmov_ctrl );
657 _igvn.replace_node( phi, cmov );
658 #ifndef PRODUCT
659 if (TraceLoopOpts) {
660 tty->print("CMOV ");
661 r_loop->dump_head();
662 if (Verbose) {
663 bol->in(1)->dump(1);
664 cmov->dump(1);
665 }
666 }
667 if (VerifyLoopOptimizations) verify();
668 #endif
669 }
670
671 // The useless CFG diamond will fold up later; see the optimization in
672 // RegionNode::Ideal.
673 _igvn._worklist.push(region);
674
675 return iff->in(1);
676 }
677
678 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
679 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
680 Node* u = m->fast_out(i);
681 if (u->is_CFG()) {
682 if (u->Opcode() == Op_NeverBranch) {
683 u = ((NeverBranchNode*)u)->proj_out(0);
684 enqueue_cfg_uses(u, wq);
685 } else {
686 wq.push(u);
687 }
688 }
689 }
690 }
691
692 // Try moving a store out of a loop, right before the loop
693 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
694 // Store has to be first in the loop body
695 IdealLoopTree *n_loop = get_loop(n_ctrl);
696 if (n->is_Store() && n_loop != _ltree_root &&
697 n_loop->is_loop() && n_loop->_head->is_Loop() &&
698 n->in(0) != NULL) {
699 Node* address = n->in(MemNode::Address);
700 Node* value = n->in(MemNode::ValueIn);
701 Node* mem = n->in(MemNode::Memory);
702 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
703 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
704
705 // - address and value must be loop invariant
706 // - memory must be a memory Phi for the loop
707 // - Store must be the only store on this memory slice in the
708 // loop: if there's another store following this one then value
709 // written at iteration i by the second store could be overwritten
710 // at iteration i+n by the first store: it's not safe to move the
711 // first store out of the loop
712 // - nothing must observe the memory Phi: it guarantees no read
713 // before the store, we are also guaranteed the store post
714 // dominates the loop head (ignoring a possible early
715 // exit). Otherwise there would be extra Phi involved between the
716 // loop's Phi and the store.
717 // - there must be no early exit from the loop before the Store
718 // (such an exit most of the time would be an extra use of the
719 // memory Phi but sometimes is a bottom memory Phi that takes the
720 // store as input).
721
722 if (!n_loop->is_member(address_loop) &&
723 !n_loop->is_member(value_loop) &&
724 mem->is_Phi() && mem->in(0) == n_loop->_head &&
725 mem->outcnt() == 1 &&
726 mem->in(LoopNode::LoopBackControl) == n) {
727
728 assert(n_loop->_tail != NULL, "need a tail");
729 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
730
731 // Verify that there's no early exit of the loop before the store.
732 bool ctrl_ok = false;
733 {
734 // Follow control from loop head until n, we exit the loop or
735 // we reach the tail
736 ResourceMark rm;
737 Unique_Node_List wq;
738 wq.push(n_loop->_head);
739
740 for (uint next = 0; next < wq.size(); ++next) {
741 Node *m = wq.at(next);
742 if (m == n->in(0)) {
743 ctrl_ok = true;
744 continue;
745 }
746 assert(!has_ctrl(m), "should be CFG");
747 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
748 ctrl_ok = false;
749 break;
750 }
751 enqueue_cfg_uses(m, wq);
752 if (wq.size() > 10) {
753 ctrl_ok = false;
754 break;
755 }
756 }
757 }
758 if (ctrl_ok) {
759 // move the Store
760 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
761 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
762 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
763 // Disconnect the phi now. An empty phi can confuse other
764 // optimizations in this pass of loop opts.
765 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
766 n_loop->_body.yank(mem);
767
768 set_ctrl_and_loop(n, n->in(0));
769
770 return n;
771 }
772 }
773 }
774 return NULL;
775 }
776
777 // Try moving a store out of a loop, right after the loop
778 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
779 if (n->is_Store() && n->in(0) != NULL) {
780 Node *n_ctrl = get_ctrl(n);
781 IdealLoopTree *n_loop = get_loop(n_ctrl);
782 // Store must be in a loop
783 if (n_loop != _ltree_root && !n_loop->_irreducible) {
784 Node* address = n->in(MemNode::Address);
785 Node* value = n->in(MemNode::ValueIn);
786 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
787 // address must be loop invariant
788 if (!n_loop->is_member(address_loop)) {
789 // Store must be last on this memory slice in the loop and
790 // nothing in the loop must observe it
791 Node* phi = NULL;
792 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
793 Node* u = n->fast_out(i);
794 if (has_ctrl(u)) { // control use?
795 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
796 if (!n_loop->is_member(u_loop)) {
797 continue;
798 }
799 if (u->is_Phi() && u->in(0) == n_loop->_head) {
800 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
801 // multiple phis on the same slice are possible
802 if (phi != NULL) {
803 return;
804 }
805 phi = u;
806 continue;
807 }
808 }
809 return;
810 }
811 if (phi != NULL) {
812 // Nothing in the loop before the store (next iteration)
813 // must observe the stored value
814 bool mem_ok = true;
815 {
816 ResourceMark rm;
817 Unique_Node_List wq;
818 wq.push(phi);
819 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
820 Node *m = wq.at(next);
821 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
822 Node* u = m->fast_out(i);
823 if (u->is_Store() || u->is_Phi()) {
824 if (u != n) {
825 wq.push(u);
826 mem_ok = (wq.size() <= 10);
827 }
828 } else {
829 mem_ok = false;
830 break;
831 }
832 }
833 }
834 }
835 if (mem_ok) {
836 // Move the store out of the loop if the LCA of all
837 // users (except for the phi) is outside the loop.
838 Node* hook = new Node(1);
839 _igvn.rehash_node_delayed(phi);
840 int count = phi->replace_edge(n, hook);
841 assert(count > 0, "inconsistent phi");
842
843 // Compute latest point this store can go
844 Node* lca = get_late_ctrl(n, get_ctrl(n));
845 if (n_loop->is_member(get_loop(lca))) {
846 // LCA is in the loop - bail out
847 _igvn.replace_node(hook, n);
848 return;
849 }
850 #ifdef ASSERT
851 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
852 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
853 n_loop->_head->as_Loop()->verify_strip_mined(1);
854 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
855 IdealLoopTree* outer_loop = get_loop(outer);
856 assert(n_loop->_parent == outer_loop, "broken loop tree");
857 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
858 }
859 #endif
860
861 // Move store out of the loop
862 _igvn.replace_node(hook, n->in(MemNode::Memory));
863 _igvn.replace_input_of(n, 0, lca);
864 set_ctrl_and_loop(n, lca);
865
866 // Disconnect the phi now. An empty phi can confuse other
867 // optimizations in this pass of loop opts..
868 if (phi->in(LoopNode::LoopBackControl) == phi) {
869 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
870 n_loop->_body.yank(phi);
871 }
872 }
873 }
874 }
875 }
876 }
877 }
878
879 //------------------------------split_if_with_blocks_pre-----------------------
880 // Do the real work in a non-recursive function. Data nodes want to be
881 // cloned in the pre-order so they can feed each other nicely.
882 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
883 // Cloning these guys is unlikely to win
884 int n_op = n->Opcode();
885 if( n_op == Op_MergeMem ) return n;
886 if( n->is_Proj() ) return n;
887 // Do not clone-up CmpFXXX variations, as these are always
888 // followed by a CmpI
889 if( n->is_Cmp() ) return n;
890 // Attempt to use a conditional move instead of a phi/branch
891 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) {
892 Node *cmov = conditional_move( n );
893 if( cmov ) return cmov;
894 }
895 if( n->is_CFG() || n->is_LoadStore() )
896 return n;
897 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd
898 n_op == Op_Opaque2 ) {
899 if( !C->major_progress() ) // If chance of no more loop opts...
900 _igvn._worklist.push(n); // maybe we'll remove them
901 return n;
902 }
903
904 if( n->is_Con() ) return n; // No cloning for Con nodes
905
906 Node *n_ctrl = get_ctrl(n);
907 if( !n_ctrl ) return n; // Dead node
908
909 Node* res = try_move_store_before_loop(n, n_ctrl);
910 if (res != NULL) {
911 return n;
912 }
913
914 // Attempt to remix address expressions for loop invariants
915 Node *m = remix_address_expressions( n );
916 if( m ) return m;
917
918 if (n->is_ConstraintCast()) {
919 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
920 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
921 // Node control inputs don't necessarily agree with loop control info (due to
922 // transformations happened in between), thus additional dominance check is needed
923 // to keep loop info valid.
924 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
925 _igvn.replace_node(n, dom_cast);
926 return dom_cast;
927 }
928 }
929
930 // Determine if the Node has inputs from some local Phi.
931 // Returns the block to clone thru.
932 Node *n_blk = has_local_phi_input( n );
933 if( !n_blk ) return n;
934
935 // Do not clone the trip counter through on a CountedLoop
936 // (messes up the canonical shape).
937 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n;
938
939 // Check for having no control input; not pinned. Allow
940 // dominating control.
941 if (n->in(0)) {
942 Node *dom = idom(n_blk);
943 if (dom_lca(n->in(0), dom) != n->in(0)) {
944 return n;
945 }
946 }
947 // Policy: when is it profitable. You must get more wins than
948 // policy before it is considered profitable. Policy is usually 0,
949 // so 1 win is considered profitable. Big merges will require big
950 // cloning, so get a larger policy.
951 int policy = n_blk->req() >> 2;
952
953 // If the loop is a candidate for range check elimination,
954 // delay splitting through it's phi until a later loop optimization
955 if (n_blk->is_CountedLoop()) {
956 IdealLoopTree *lp = get_loop(n_blk);
957 if (lp && lp->_rce_candidate) {
958 return n;
959 }
960 }
961
962 // Use same limit as split_if_with_blocks_post
963 if( C->live_nodes() > 35000 ) return n; // Method too big
964
965 // Split 'n' through the merge point if it is profitable
966 Node *phi = split_thru_phi( n, n_blk, policy );
967 if (!phi) return n;
968
969 // Found a Phi to split thru!
970 // Replace 'n' with the new phi
971 _igvn.replace_node( n, phi );
972 // Moved a load around the loop, 'en-registering' something.
973 if (n_blk->is_Loop() && n->is_Load() &&
974 !phi->in(LoopNode::LoopBackControl)->is_Load())
975 C->set_major_progress();
976
977 return phi;
978 }
979
980 static bool merge_point_too_heavy(Compile* C, Node* region) {
981 // Bail out if the region and its phis have too many users.
982 int weight = 0;
983 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
984 weight += region->fast_out(i)->outcnt();
985 }
986 int nodes_left = C->max_node_limit() - C->live_nodes();
987 if (weight * 8 > nodes_left) {
988 if (PrintOpto) {
989 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
990 }
991 return true;
992 } else {
993 return false;
994 }
995 }
996
997 static bool merge_point_safe(Node* region) {
998 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
999 // having a PhiNode input. This sidesteps the dangerous case where the split
1000 // ConvI2LNode may become TOP if the input Value() does not
1001 // overlap the ConvI2L range, leaving a node which may not dominate its
1002 // uses.
1003 // A better fix for this problem can be found in the BugTraq entry, but
1004 // expediency for Mantis demands this hack.
1005 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop
1006 // split_if_with_blocks from splitting a block because we could not move around
1007 // the FastLockNode.
1008 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1009 Node* n = region->fast_out(i);
1010 if (n->is_Phi()) {
1011 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1012 Node* m = n->fast_out(j);
1013 if (m->is_FastLock())
1014 return false;
1015 #ifdef _LP64
1016 if (m->Opcode() == Op_ConvI2L)
1017 return false;
1018 if (m->is_CastII() && m->isa_CastII()->has_range_check()) {
1019 return false;
1020 }
1021 #endif
1022 }
1023 }
1024 }
1025 return true;
1026 }
1027
1028
1029 //------------------------------place_near_use---------------------------------
1030 // Place some computation next to use but not inside inner loops.
1031 // For inner loop uses move it to the preheader area.
1032 Node *PhaseIdealLoop::place_near_use(Node *useblock) const {
1033 IdealLoopTree *u_loop = get_loop( useblock );
1034 if (u_loop->_irreducible) {
1035 return useblock;
1036 }
1037 if (u_loop->_child) {
1038 if (useblock == u_loop->_head && u_loop->_head->is_OuterStripMinedLoop()) {
1039 return u_loop->_head->in(LoopNode::EntryControl);
1040 }
1041 return useblock;
1042 }
1043 return u_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
1044 }
1045
1046
1047 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1048 if (!n->is_If() || n->is_CountedLoopEnd()) {
1049 return false;
1050 }
1051 if (!n->in(0)->is_Region()) {
1052 return false;
1053 }
1054 Node* region = n->in(0);
1055 Node* dom = idom(region);
1056 if (!dom->is_If() || dom->in(1) != n->in(1)) {
1057 return false;
1058 }
1059 IfNode* dom_if = dom->as_If();
1060 Node* proj_true = dom_if->proj_out(1);
1061 Node* proj_false = dom_if->proj_out(0);
1062
1063 for (uint i = 1; i < region->req(); i++) {
1064 if (is_dominator(proj_true, region->in(i))) {
1065 continue;
1066 }
1067 if (is_dominator(proj_false, region->in(i))) {
1068 continue;
1069 }
1070 return false;
1071 }
1072
1073 return true;
1074 }
1075
1076 bool PhaseIdealLoop::can_split_if(Node *n_ctrl) {
1077 if (C->live_nodes() > 35000) {
1078 return false; // Method too big
1079 }
1080
1081 // Do not do 'split-if' if irreducible loops are present.
1082 if (_has_irreducible_loops) {
1083 return false;
1084 }
1085
1086 if (merge_point_too_heavy(C, n_ctrl)) {
1087 return false;
1088 }
1089
1090 // Do not do 'split-if' if some paths are dead. First do dead code
1091 // elimination and then see if its still profitable.
1092 for (uint i = 1; i < n_ctrl->req(); i++) {
1093 if (n_ctrl->in(i) == C->top()) {
1094 return false;
1095 }
1096 }
1097
1098 // If trying to do a 'Split-If' at the loop head, it is only
1099 // profitable if the cmp folds up on BOTH paths. Otherwise we
1100 // risk peeling a loop forever.
1101
1102 // CNC - Disabled for now. Requires careful handling of loop
1103 // body selection for the cloned code. Also, make sure we check
1104 // for any input path not being in the same loop as n_ctrl. For
1105 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1106 // because the alternative loop entry points won't be converted
1107 // into LoopNodes.
1108 IdealLoopTree *n_loop = get_loop(n_ctrl);
1109 for (uint j = 1; j < n_ctrl->req(); j++) {
1110 if (get_loop(n_ctrl->in(j)) != n_loop) {
1111 return false;
1112 }
1113 }
1114
1115 // Check for safety of the merge point.
1116 if (!merge_point_safe(n_ctrl)) {
1117 return false;
1118 }
1119
1120 return true;
1121 }
1122
1123 bool PhaseIdealLoop::replace_with_dominating_barrier(LoadBarrierNode* lb, bool last_round) {
1124 LoadBarrierNode* lb2 = lb->has_dominating_barrier(this, false, last_round);
1125 if (lb2 != NULL) {
1126 if (lb->in(LoadBarrierNode::Oop) != lb2->in(LoadBarrierNode::Oop)) {
1127 assert(lb->in(LoadBarrierNode::Address) == lb2->in(LoadBarrierNode::Address), "");
1128 _igvn.replace_input_of(lb, LoadBarrierNode::Similar, lb2->proj_out(LoadBarrierNode::Oop));
1129 C->set_major_progress();
1130 } else {
1131 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1132 lb->fix_similar_in_uses(&_igvn);
1133
1134 Node* val = lb->proj_out(LoadBarrierNode::Oop);
1135 assert(lb2->has_true_uses(), "");
1136 assert(lb2->in(LoadBarrierNode::Oop) == lb->in(LoadBarrierNode::Oop), "");
1137
1138 lazy_update(lb, lb->in(LoadBarrierNode::Control));
1139 lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
1140 _igvn.replace_node(val, lb2->proj_out(LoadBarrierNode::Oop));
1141
1142 return true;
1143 }
1144 }
1145 return false;
1146 }
1147
1148 Node* PhaseIdealLoop::find_dominating_memory(Node* mem, Node* dom, int i) {
1149 assert(dom->is_Region() || i == -1, "");
1150 Node* m = mem;
1151 while(is_dominator(dom, has_ctrl(m) ? get_ctrl(m) : m->in(0))) {
1152 if (m->is_Mem()) {
1153 assert(m->as_Mem()->adr_type() == TypeRawPtr::BOTTOM, "");
1154 m = m->in(MemNode::Memory);
1155 } else if (m->is_MergeMem()) {
1156 m = m->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1157 } else if (m->is_Phi()) {
1158 if (m->in(0) == dom && i != -1) {
1159 m = m->in(i);
1160 break;
1161 } else {
1162 m = m->in(LoopNode::EntryControl);
1163 }
1164 } else if (m->is_Proj()) {
1165 m = m->in(0);
1166 } else if (m->is_SafePoint() || m->is_MemBar()) {
1167 m = m->in(TypeFunc::Memory);
1168 } else {
1169 #ifdef ASSERT
1170 m->dump();
1171 #endif
1172 ShouldNotReachHere();
1173 }
1174 }
1175 return m;
1176 }
1177
1178 LoadBarrierNode* PhaseIdealLoop::clone_load_barrier(LoadBarrierNode* lb, Node* ctl, Node* mem, Node* oop_in) {
1179 Node* the_clone = lb->clone();
1180 the_clone->set_req(LoadBarrierNode::Control, ctl);
1181 the_clone->set_req(LoadBarrierNode::Memory, mem);
1182 if (oop_in != NULL) {
1183 the_clone->set_req(LoadBarrierNode::Oop, oop_in);
1184 }
1185
1186 LoadBarrierNode* new_lb = the_clone->as_LoadBarrier();
1187 _igvn.register_new_node_with_optimizer(new_lb);
1188 IdealLoopTree *loop = get_loop(new_lb->in(0));
1189 set_ctrl(new_lb, new_lb->in(0));
1190 set_loop(new_lb, loop);
1191 set_idom(new_lb, new_lb->in(0), dom_depth(new_lb->in(0))+1);
1192 if (!loop->_child) {
1193 loop->_body.push(new_lb);
1194 }
1195
1196 Node* proj_ctl = new ProjNode(new_lb, LoadBarrierNode::Control);
1197 _igvn.register_new_node_with_optimizer(proj_ctl);
1198 set_ctrl(proj_ctl, proj_ctl->in(0));
1199 set_loop(proj_ctl, loop);
1200 set_idom(proj_ctl, new_lb, dom_depth(new_lb)+1);
1201 if (!loop->_child) {
1202 loop->_body.push(proj_ctl);
1203 }
1204
1205 Node* proj_oop = new ProjNode(new_lb, LoadBarrierNode::Oop);
1206 register_new_node(proj_oop, new_lb);
1207
1208 if (!new_lb->in(LoadBarrierNode::Similar)->is_top()) {
1209 LoadBarrierNode* similar = new_lb->in(LoadBarrierNode::Similar)->in(0)->as_LoadBarrier();
1210 if (!is_dominator(similar, ctl)) {
1211 _igvn.replace_input_of(new_lb, LoadBarrierNode::Similar, C->top());
1212 }
1213 }
1214
1215 return new_lb;
1216 }
1217
1218 void PhaseIdealLoop::replace_barrier(LoadBarrierNode* lb, Node* new_val) {
1219 Node* val = lb->proj_out(LoadBarrierNode::Oop);
1220 _igvn.replace_node(val, new_val);
1221 lazy_update(lb, lb->in(LoadBarrierNode::Control));
1222 lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
1223 }
1224
1225 bool PhaseIdealLoop::split_barrier_thru_phi(LoadBarrierNode* lb) {
1226 if (lb->in(LoadBarrierNode::Oop)->is_Phi()) {
1227 Node* oop_phi = lb->in(LoadBarrierNode::Oop);
1228
1229 if (oop_phi->req() == 2) {
1230 // Ignore phis with only one input
1231 return false;
1232 }
1233
1234 if (is_dominator(get_ctrl(lb->in(LoadBarrierNode::Address)), oop_phi->in(0)) && get_ctrl(lb->in(LoadBarrierNode::Address)) != oop_phi->in(0) /*&& (get_ctrl(lb->in(LoadBarrierNode::Memory)) != lb->in(0) || lb->in(LoadBarrierNode::Memory)->is_Phi())*/) {
1235 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1236 lb->fix_similar_in_uses(&_igvn);
1237
1238 RegionNode* region = oop_phi->in(0)->as_Region();
1239
1240 int backedge = LoopNode::LoopBackControl;
1241 if (region->is_Loop() && region->in(backedge)->is_Proj() && region->in(backedge)->in(0)->is_If()) {
1242 Node* c = region->in(backedge)->in(0)->in(0);
1243 assert(c->unique_ctrl_out() == region->in(backedge)->in(0), "");
1244 Node* oop = lb->in(LoadBarrierNode::Oop)->in(backedge);
1245 Node* oop_c = has_ctrl(oop) ? get_ctrl(oop) : oop;
1246 if (!is_dominator(oop_c, c)) {
1247 return false;
1248 }
1249 }
1250
1251 Node *phi = oop_phi->clone();
1252
1253 for (uint i = 1; i < region->req(); i++) {
1254 Node* ctrl = region->in(i);
1255 if (ctrl != C->top()) {
1256 assert(!is_dominator(ctrl, region) || region->is_Loop(), "");
1257
1258 Node* mem = lb->in(LoadBarrierNode::Memory);
1259 Node* m = find_dominating_memory(mem, region, i);
1260
1261 if (region->is_Loop() && i == LoopNode::LoopBackControl && ctrl->is_Proj() && ctrl->in(0)->is_If()) {
1262 ctrl = ctrl->in(0)->in(0);
1263 }
1264
1265 LoadBarrierNode* new_lb = clone_load_barrier(lb, ctrl, m, lb->in(LoadBarrierNode::Oop)->in(i));
1266
1267 Node* out_ctrl = new_lb->proj_out(LoadBarrierNode::Control);
1268 if (ctrl == region->in(i)) {
1269 _igvn.replace_input_of(region, i, new_lb->proj_out(LoadBarrierNode::Control));
1270 } else {
1271 Node* iff = region->in(i)->in(0);
1272 Node* out_ctrl = new_lb->proj_out(LoadBarrierNode::Control);
1273 _igvn.replace_input_of(iff, 0, out_ctrl);
1274 set_idom(iff, out_ctrl, dom_depth(out_ctrl)+1);
1275 }
1276 phi->set_req(i, new_lb->proj_out(LoadBarrierNode::Oop));
1277 }
1278 }
1279 register_new_node(phi, region);
1280
1281 replace_barrier(lb, phi);
1282
1283 if (region->is_Loop()) {
1284 // Load barrier moved to the back edge of the Loop may now
1285 // have a safepoint on the path to the barrier on the Similar
1286 // edge
1287 _igvn.replace_input_of(phi->in(LoopNode::LoopBackControl)->in(0), LoadBarrierNode::Similar, C->top());
1288 Node* head = region->in(LoopNode::EntryControl);
1289 set_idom(region, head, dom_depth(head)+1);
1290 recompute_dom_depth();
1291 if (head->is_CountedLoop() && head->as_CountedLoop()->is_main_loop()) {
1292 head->as_CountedLoop()->set_normal_loop();
1293 }
1294 }
1295 return true;
1296 }
1297 }
1298 return false;
1299 }
1300
1301 bool PhaseIdealLoop::move_out_of_loop(LoadBarrierNode* lb) {
1302 IdealLoopTree *lb_loop = get_loop(lb->in(0));
1303 if (lb_loop != _ltree_root && !lb_loop->_irreducible) {
1304 Node* oop_ctrl = get_ctrl(lb->in(LoadBarrierNode::Oop));
1305 IdealLoopTree *oop_loop = get_loop(oop_ctrl);
1306 IdealLoopTree* adr_loop = get_loop(get_ctrl(lb->in(LoadBarrierNode::Address)));
1307 if (!lb_loop->is_member(oop_loop) && !lb_loop->is_member(adr_loop)) {
1308 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1309 lb->fix_similar_in_uses(&_igvn);
1310
1311 Node* head = lb_loop->_head;
1312 assert(head->is_Loop(), "");
1313
1314 if (is_dominator(head, oop_ctrl)) {
1315 assert(oop_ctrl->Opcode() == Op_CProj && oop_ctrl->in(0)->Opcode() == Op_NeverBranch, "");
1316 assert(lb_loop->is_member(get_loop(oop_ctrl->in(0)->in(0))), "");
1317 return false;
1318 }
1319
1320 if (head->is_CountedLoop()) {
1321 CountedLoopNode* cloop = head->as_CountedLoop();
1322 if (cloop->is_main_loop()) {
1323 cloop->set_normal_loop();
1324 }
1325 // When we are moving barrier out of a counted loop,
1326 // make sure we move it all the way out of the strip mined outer loop.
1327 if (cloop->is_strip_mined()) {
1328 head = cloop->outer_loop();
1329 }
1330 }
1331
1332 Node* mem = lb->in(LoadBarrierNode::Memory);
1333 Node* m = find_dominating_memory(mem, head);
1334
1335 LoadBarrierNode* new_lb = clone_load_barrier(lb, head->in(LoopNode::EntryControl), m, NULL);
1336
1337 assert(idom(head) == head->in(LoopNode::EntryControl), "");
1338 Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
1339 _igvn.replace_input_of(head, LoopNode::EntryControl, proj_ctl);
1340 set_idom(head, proj_ctl, dom_depth(proj_ctl)+1);
1341
1342 replace_barrier(lb, new_lb->proj_out(LoadBarrierNode::Oop));
1343
1344 recompute_dom_depth();
1345
1346 return true;
1347 }
1348 }
1349 return false;
1350 }
1351
1352 bool PhaseIdealLoop::common_barriers(LoadBarrierNode* lb) {
1353 Node* in_val = lb->in(LoadBarrierNode::Oop);
1354 for (DUIterator_Fast imax, i = in_val->fast_outs(imax); i < imax; i++) {
1355 Node* u = in_val->fast_out(i);
1356 if (u != lb && u->is_LoadBarrier() && u->as_LoadBarrier()->has_true_uses()) {
1357 Node* this_ctrl = lb->in(LoadBarrierNode::Control);
1358 Node* other_ctrl = u->in(LoadBarrierNode::Control);
1359
1360 Node* lca = dom_lca(this_ctrl, other_ctrl);
1361 bool ok = true;
1362
1363 Node* proj1 = NULL;
1364 Node* proj2 = NULL;
1365
1366 while (this_ctrl != lca && ok) {
1367 if (this_ctrl->in(0) != NULL &&
1368 this_ctrl->in(0)->is_MultiBranch()) {
1369 if (this_ctrl->in(0)->in(0) == lca) {
1370 assert(proj1 == NULL, "");
1371 assert(this_ctrl->is_Proj(), "");
1372 proj1 = this_ctrl;
1373 } else if (!(this_ctrl->in(0)->is_If() && this_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
1374 ok = false;
1375 }
1376 }
1377 this_ctrl = idom(this_ctrl);
1378 }
1379 while (other_ctrl != lca && ok) {
1380 if (other_ctrl->in(0) != NULL &&
1381 other_ctrl->in(0)->is_MultiBranch()) {
1382 if (other_ctrl->in(0)->in(0) == lca) {
1383 assert(other_ctrl->is_Proj(), "");
1384 assert(proj2 == NULL, "");
1385 proj2 = other_ctrl;
1386 } else if (!(other_ctrl->in(0)->is_If() && other_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
1387 ok = false;
1388 }
1389 }
1390 other_ctrl = idom(other_ctrl);
1391 }
1392 assert(proj1 == NULL || proj2 == NULL || proj1->in(0) == proj2->in(0), "");
1393 if (ok && proj1 && proj2 && proj1 != proj2 && proj1->in(0)->is_If()) {
1394 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1395 lb->fix_similar_in_uses(&_igvn);
1396 u->as_LoadBarrier()->fix_similar_in_uses(&_igvn);
1397
1398 Node* split = lca->unique_ctrl_out();
1399 assert(split->in(0) == lca, "");
1400
1401 Node* mem = lb->in(LoadBarrierNode::Memory);
1402 Node* m = find_dominating_memory(mem, split);
1403 LoadBarrierNode* new_lb = clone_load_barrier(lb, lca, m, NULL);
1404
1405 Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
1406 _igvn.replace_input_of(split, 0, new_lb->proj_out(LoadBarrierNode::Control));
1407 set_idom(split, proj_ctl, dom_depth(proj_ctl)+1);
1408
1409 Node* proj_oop = new_lb->proj_out(LoadBarrierNode::Oop);
1410 replace_barrier(lb, proj_oop);
1411 replace_barrier(u->as_LoadBarrier(), proj_oop);
1412
1413 recompute_dom_depth();
1414
1415 return true;
1416 }
1417 }
1418 }
1419 return false;
1420 }
1421
1422 void PhaseIdealLoop::optimize_load_barrier(LoadBarrierNode* lb, bool last_round) {
1423 if (!C->directive()->OptimizeLoadBarriersOption) {
1424 return;
1425 }
1426
1427 if (lb->has_true_uses()) {
1428
1429 if (replace_with_dominating_barrier(lb, last_round)) {
1430 return;
1431 }
1432
1433 if (split_barrier_thru_phi(lb)) {
1434 return;
1435 }
1436
1437 if (move_out_of_loop(lb)) {
1438 return;
1439 }
1440
1441 if (common_barriers(lb)) {
1442 return;
1443 }
1444 }
1445 }
1446
1447 //------------------------------split_if_with_blocks_post----------------------
1448 // Do the real work in a non-recursive function. CFG hackery wants to be
1449 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1450 // info.
1451 void PhaseIdealLoop::split_if_with_blocks_post(Node *n, bool last_round) {
1452
1453 // Cloning Cmp through Phi's involves the split-if transform.
1454 // FastLock is not used by an If
1455 if (n->is_Cmp() && !n->is_FastLock() && !last_round) {
1456 Node *n_ctrl = get_ctrl(n);
1457 // Determine if the Node has inputs from some local Phi.
1458 // Returns the block to clone thru.
1459 Node *n_blk = has_local_phi_input(n);
1460 if (n_blk != n_ctrl) {
1461 return;
1462 }
1463
1464 if (!can_split_if(n_ctrl)) {
1465 return;
1466 }
1467
1468 if (n->outcnt() != 1) {
1469 return; // Multiple bool's from 1 compare?
1470 }
1471 Node *bol = n->unique_out();
1472 assert(bol->is_Bool(), "expect a bool here");
1473 if (bol->outcnt() != 1) {
1474 return;// Multiple branches from 1 compare?
1475 }
1476 Node *iff = bol->unique_out();
1477
1478 // Check some safety conditions
1479 if (iff->is_If()) { // Classic split-if?
1480 if (iff->in(0) != n_ctrl) {
1481 return; // Compare must be in same blk as if
1482 }
1483 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1484 // Can't split CMove with different control edge.
1485 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) {
1486 return;
1487 }
1488 if (get_ctrl(iff->in(2)) == n_ctrl ||
1489 get_ctrl(iff->in(3)) == n_ctrl) {
1490 return; // Inputs not yet split-up
1491 }
1492 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1493 return; // Loop-invar test gates loop-varying CMOVE
1494 }
1495 } else {
1496 return; // some other kind of node, such as an Allocate
1497 }
1498
1499 // When is split-if profitable? Every 'win' on means some control flow
1500 // goes dead, so it's almost always a win.
1501 int policy = 0;
1502 // Split compare 'n' through the merge point if it is profitable
1503 Node *phi = split_thru_phi( n, n_ctrl, policy);
1504 if (!phi) {
1505 return;
1506 }
1507
1508 // Found a Phi to split thru!
1509 // Replace 'n' with the new phi
1510 _igvn.replace_node(n, phi);
1511
1512 // Now split the bool up thru the phi
1513 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1514 guarantee(bolphi != NULL, "null boolean phi node");
1515
1516 _igvn.replace_node(bol, bolphi);
1517 assert(iff->in(1) == bolphi, "");
1518
1519 if (bolphi->Value(&_igvn)->singleton()) {
1520 return;
1521 }
1522
1523 // Conditional-move? Must split up now
1524 if (!iff->is_If()) {
1525 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1526 _igvn.replace_node(iff, cmovphi);
1527 return;
1528 }
1529
1530 // Now split the IF
1531 do_split_if(iff);
1532 return;
1533 }
1534
1535 // Two identical ifs back to back can be merged
1536 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1537 Node *n_ctrl = n->in(0);
1538 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1));
1539 IfNode* dom_if = idom(n_ctrl)->as_If();
1540 Node* proj_true = dom_if->proj_out(1);
1541 Node* proj_false = dom_if->proj_out(0);
1542 Node* con_true = _igvn.makecon(TypeInt::ONE);
1543 Node* con_false = _igvn.makecon(TypeInt::ZERO);
1544
1545 for (uint i = 1; i < n_ctrl->req(); i++) {
1546 if (is_dominator(proj_true, n_ctrl->in(i))) {
1547 bolphi->init_req(i, con_true);
1548 } else {
1549 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if");
1550 bolphi->init_req(i, con_false);
1551 }
1552 }
1553 register_new_node(bolphi, n_ctrl);
1554 _igvn.replace_input_of(n, 1, bolphi);
1555
1556 // Now split the IF
1557 do_split_if(n);
1558 return;
1559 }
1560
1561 // Check for an IF ready to split; one that has its
1562 // condition codes input coming from a Phi at the block start.
1563 int n_op = n->Opcode();
1564
1565 // Check for an IF being dominated by another IF same test
1566 if (n_op == Op_If ||
1567 n_op == Op_RangeCheck) {
1568 Node *bol = n->in(1);
1569 uint max = bol->outcnt();
1570 // Check for same test used more than once?
1571 if (max > 1 && bol->is_Bool()) {
1572 // Search up IDOMs to see if this IF is dominated.
1573 Node *cutoff = get_ctrl(bol);
1574
1575 // Now search up IDOMs till cutoff, looking for a dominating test
1576 Node *prevdom = n;
1577 Node *dom = idom(prevdom);
1578 while (dom != cutoff) {
1579 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) {
1580 // Replace the dominated test with an obvious true or false.
1581 // Place it on the IGVN worklist for later cleanup.
1582 C->set_major_progress();
1583 dominated_by(prevdom, n, false, true);
1584 #ifndef PRODUCT
1585 if( VerifyLoopOptimizations ) verify();
1586 #endif
1587 return;
1588 }
1589 prevdom = dom;
1590 dom = idom(prevdom);
1591 }
1592 }
1593 }
1594
1595 // See if a shared loop-varying computation has no loop-varying uses.
1596 // Happens if something is only used for JVM state in uncommon trap exits,
1597 // like various versions of induction variable+offset. Clone the
1598 // computation per usage to allow it to sink out of the loop.
1599 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about)
1600 Node *n_ctrl = get_ctrl(n);
1601 IdealLoopTree *n_loop = get_loop(n_ctrl);
1602 if( n_loop != _ltree_root ) {
1603 DUIterator_Fast imax, i = n->fast_outs(imax);
1604 for (; i < imax; i++) {
1605 Node* u = n->fast_out(i);
1606 if( !has_ctrl(u) ) break; // Found control user
1607 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
1608 if( u_loop == n_loop ) break; // Found loop-varying use
1609 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop
1610 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003
1611 }
1612 bool did_break = (i < imax); // Did we break out of the previous loop?
1613 if (!did_break && n->outcnt() > 1) { // All uses in outer loops!
1614 Node *late_load_ctrl = NULL;
1615 if (n->is_Load()) {
1616 // If n is a load, get and save the result from get_late_ctrl(),
1617 // to be later used in calculating the control for n's clones.
1618 clear_dom_lca_tags();
1619 late_load_ctrl = get_late_ctrl(n, n_ctrl);
1620 }
1621 // If n is a load, and the late control is the same as the current
1622 // control, then the cloning of n is a pointless exercise, because
1623 // GVN will ensure that we end up where we started.
1624 if (!n->is_Load() || late_load_ctrl != n_ctrl) {
1625 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) {
1626 Node *u = n->last_out(j); // Clone private computation per use
1627 _igvn.rehash_node_delayed(u);
1628 Node *x = n->clone(); // Clone computation
1629 Node *x_ctrl = NULL;
1630 if( u->is_Phi() ) {
1631 // Replace all uses of normal nodes. Replace Phi uses
1632 // individually, so the separate Nodes can sink down
1633 // different paths.
1634 uint k = 1;
1635 while( u->in(k) != n ) k++;
1636 u->set_req( k, x );
1637 // x goes next to Phi input path
1638 x_ctrl = u->in(0)->in(k);
1639 --j;
1640 } else { // Normal use
1641 // Replace all uses
1642 for( uint k = 0; k < u->req(); k++ ) {
1643 if( u->in(k) == n ) {
1644 u->set_req( k, x );
1645 --j;
1646 }
1647 }
1648 x_ctrl = get_ctrl(u);
1649 }
1650
1651 // Find control for 'x' next to use but not inside inner loops.
1652 // For inner loop uses get the preheader area.
1653 x_ctrl = place_near_use(x_ctrl);
1654
1655 if (n->is_Load()) {
1656 // For loads, add a control edge to a CFG node outside of the loop
1657 // to force them to not combine and return back inside the loop
1658 // during GVN optimization (4641526).
1659 //
1660 // Because we are setting the actual control input, factor in
1661 // the result from get_late_ctrl() so we respect any
1662 // anti-dependences. (6233005).
1663 x_ctrl = dom_lca(late_load_ctrl, x_ctrl);
1664
1665 // Don't allow the control input to be a CFG splitting node.
1666 // Such nodes should only have ProjNodes as outs, e.g. IfNode
1667 // should only have IfTrueNode and IfFalseNode (4985384).
1668 x_ctrl = find_non_split_ctrl(x_ctrl);
1669 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1670
1671 x->set_req(0, x_ctrl);
1672 }
1673 register_new_node(x, x_ctrl);
1674
1675 // Some institutional knowledge is needed here: 'x' is
1676 // yanked because if the optimizer runs GVN on it all the
1677 // cloned x's will common up and undo this optimization and
1678 // be forced back in the loop. This is annoying because it
1679 // makes +VerifyOpto report false-positives on progress. I
1680 // tried setting control edges on the x's to force them to
1681 // not combine, but the matching gets worried when it tries
1682 // to fold a StoreP and an AddP together (as part of an
1683 // address expression) and the AddP and StoreP have
1684 // different controls.
1685 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x);
1686 }
1687 _igvn.remove_dead_node(n);
1688 }
1689 }
1690 }
1691 }
1692
1693 try_move_store_after_loop(n);
1694
1695 // Check for Opaque2's who's loop has disappeared - who's input is in the
1696 // same loop nest as their output. Remove 'em, they are no longer useful.
1697 if( n_op == Op_Opaque2 &&
1698 n->in(1) != NULL &&
1699 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) {
1700 _igvn.replace_node( n, n->in(1) );
1701 }
1702
1703 if (n->is_LoadBarrier()) {
1704 optimize_load_barrier(n->as_LoadBarrier(), last_round);
1705 }
1706 }
1707
1708 //------------------------------split_if_with_blocks---------------------------
1709 // Check for aggressive application of 'split-if' optimization,
1710 // using basic block level info.
1711 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack, bool last_round) {
1712 Node *n = C->root();
1713 visited.set(n->_idx); // first, mark node as visited
1714 // Do pre-visit work for root
1715 n = split_if_with_blocks_pre( n );
1716 uint cnt = n->outcnt();
1717 uint i = 0;
1718 while (true) {
1719 // Visit all children
1720 if (i < cnt) {
1721 Node* use = n->raw_out(i);
1722 ++i;
1723 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1724 // Now do pre-visit work for this use
1725 use = split_if_with_blocks_pre( use );
1726 nstack.push(n, i); // Save parent and next use's index.
1727 n = use; // Process all children of current use.
1728 cnt = use->outcnt();
1729 i = 0;
1730 }
1731 }
1732 else {
1733 // All of n's children have been processed, complete post-processing.
1734 if (cnt != 0 && !n->is_Con()) {
1735 assert(has_node(n), "no dead nodes");
1736 split_if_with_blocks_post(n, last_round);
1737 }
1738 if (nstack.is_empty()) {
1739 // Finished all nodes on stack.
1740 break;
1741 }
1742 // Get saved parent node and next use's index. Visit the rest of uses.
1743 n = nstack.node();
1744 cnt = n->outcnt();
1745 i = nstack.index();
1746 nstack.pop();
1747 }
1748 }
1749 }
1750
1751
1752 //=============================================================================
1753 //
1754 // C L O N E A L O O P B O D Y
1755 //
1756
1757 //------------------------------clone_iff--------------------------------------
1758 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1759 // "Nearly" because all Nodes have been cloned from the original in the loop,
1760 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1761 // through the Phi recursively, and return a Bool.
1762 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) {
1763
1764 // Convert this Phi into a Phi merging Bools
1765 uint i;
1766 for (i = 1; i < phi->req(); i++) {
1767 Node *b = phi->in(i);
1768 if (b->is_Phi()) {
1769 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop));
1770 } else {
1771 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
1772 }
1773 }
1774
1775 Node* n = phi->in(1);
1776 Node* sample_opaque = NULL;
1777 Node *sample_bool = NULL;
1778 if (n->Opcode() == Op_Opaque4) {
1779 sample_opaque = n;
1780 sample_bool = n->in(1);
1781 assert(sample_bool->is_Bool(), "wrong type");
1782 } else {
1783 sample_bool = n;
1784 }
1785 Node *sample_cmp = sample_bool->in(1);
1786
1787 // Make Phis to merge the Cmp's inputs.
1788 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
1789 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
1790 for (i = 1; i < phi->req(); i++) {
1791 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
1792 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
1793 phi1->set_req(i, n1);
1794 phi2->set_req(i, n2);
1795 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1796 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1797 }
1798 // See if these Phis have been made before.
1799 // Register with optimizer
1800 Node *hit1 = _igvn.hash_find_insert(phi1);
1801 if (hit1) { // Hit, toss just made Phi
1802 _igvn.remove_dead_node(phi1); // Remove new phi
1803 assert(hit1->is_Phi(), "" );
1804 phi1 = (PhiNode*)hit1; // Use existing phi
1805 } else { // Miss
1806 _igvn.register_new_node_with_optimizer(phi1);
1807 }
1808 Node *hit2 = _igvn.hash_find_insert(phi2);
1809 if (hit2) { // Hit, toss just made Phi
1810 _igvn.remove_dead_node(phi2); // Remove new phi
1811 assert(hit2->is_Phi(), "" );
1812 phi2 = (PhiNode*)hit2; // Use existing phi
1813 } else { // Miss
1814 _igvn.register_new_node_with_optimizer(phi2);
1815 }
1816 // Register Phis with loop/block info
1817 set_ctrl(phi1, phi->in(0));
1818 set_ctrl(phi2, phi->in(0));
1819 // Make a new Cmp
1820 Node *cmp = sample_cmp->clone();
1821 cmp->set_req(1, phi1);
1822 cmp->set_req(2, phi2);
1823 _igvn.register_new_node_with_optimizer(cmp);
1824 set_ctrl(cmp, phi->in(0));
1825
1826 // Make a new Bool
1827 Node *b = sample_bool->clone();
1828 b->set_req(1,cmp);
1829 _igvn.register_new_node_with_optimizer(b);
1830 set_ctrl(b, phi->in(0));
1831
1832 if (sample_opaque != NULL) {
1833 Node* opaque = sample_opaque->clone();
1834 opaque->set_req(1, b);
1835 _igvn.register_new_node_with_optimizer(opaque);
1836 set_ctrl(opaque, phi->in(0));
1837 return opaque;
1838 }
1839
1840 assert(b->is_Bool(), "");
1841 return b;
1842 }
1843
1844 //------------------------------clone_bool-------------------------------------
1845 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1846 // "Nearly" because all Nodes have been cloned from the original in the loop,
1847 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1848 // through the Phi recursively, and return a Bool.
1849 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) {
1850 uint i;
1851 // Convert this Phi into a Phi merging Bools
1852 for( i = 1; i < phi->req(); i++ ) {
1853 Node *b = phi->in(i);
1854 if( b->is_Phi() ) {
1855 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop ));
1856 } else {
1857 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
1858 }
1859 }
1860
1861 Node *sample_cmp = phi->in(1);
1862
1863 // Make Phis to merge the Cmp's inputs.
1864 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
1865 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
1866 for( uint j = 1; j < phi->req(); j++ ) {
1867 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
1868 Node *n1, *n2;
1869 if( cmp_top->is_Cmp() ) {
1870 n1 = cmp_top->in(1);
1871 n2 = cmp_top->in(2);
1872 } else {
1873 n1 = n2 = cmp_top;
1874 }
1875 phi1->set_req( j, n1 );
1876 phi2->set_req( j, n2 );
1877 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1878 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1879 }
1880
1881 // See if these Phis have been made before.
1882 // Register with optimizer
1883 Node *hit1 = _igvn.hash_find_insert(phi1);
1884 if( hit1 ) { // Hit, toss just made Phi
1885 _igvn.remove_dead_node(phi1); // Remove new phi
1886 assert( hit1->is_Phi(), "" );
1887 phi1 = (PhiNode*)hit1; // Use existing phi
1888 } else { // Miss
1889 _igvn.register_new_node_with_optimizer(phi1);
1890 }
1891 Node *hit2 = _igvn.hash_find_insert(phi2);
1892 if( hit2 ) { // Hit, toss just made Phi
1893 _igvn.remove_dead_node(phi2); // Remove new phi
1894 assert( hit2->is_Phi(), "" );
1895 phi2 = (PhiNode*)hit2; // Use existing phi
1896 } else { // Miss
1897 _igvn.register_new_node_with_optimizer(phi2);
1898 }
1899 // Register Phis with loop/block info
1900 set_ctrl(phi1, phi->in(0));
1901 set_ctrl(phi2, phi->in(0));
1902 // Make a new Cmp
1903 Node *cmp = sample_cmp->clone();
1904 cmp->set_req( 1, phi1 );
1905 cmp->set_req( 2, phi2 );
1906 _igvn.register_new_node_with_optimizer(cmp);
1907 set_ctrl(cmp, phi->in(0));
1908
1909 assert( cmp->is_Cmp(), "" );
1910 return (CmpNode*)cmp;
1911 }
1912
1913 //------------------------------sink_use---------------------------------------
1914 // If 'use' was in the loop-exit block, it now needs to be sunk
1915 // below the post-loop merge point.
1916 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
1917 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
1918 set_ctrl(use, post_loop);
1919 for (DUIterator j = use->outs(); use->has_out(j); j++)
1920 sink_use(use->out(j), post_loop);
1921 }
1922 }
1923
1924 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
1925 IdealLoopTree* loop, IdealLoopTree* outer_loop,
1926 Node_List*& split_if_set, Node_List*& split_bool_set,
1927 Node_List*& split_cex_set, Node_List& worklist,
1928 uint new_counter, CloneLoopMode mode) {
1929 Node* nnn = old_new[old->_idx];
1930 // Copy uses to a worklist, so I can munge the def-use info
1931 // with impunity.
1932 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
1933 worklist.push(old->fast_out(j));
1934
1935 while( worklist.size() ) {
1936 Node *use = worklist.pop();
1937 if (!has_node(use)) continue; // Ignore dead nodes
1938 if (use->in(0) == C->top()) continue;
1939 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
1940 // Check for data-use outside of loop - at least one of OLD or USE
1941 // must not be a CFG node.
1942 #ifdef ASSERT
1943 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) {
1944 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
1945 assert(mode == ControlAroundStripMined && use == sfpt, "missed a node");
1946 }
1947 #endif
1948 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
1949
1950 // If the Data use is an IF, that means we have an IF outside of the
1951 // loop that is switching on a condition that is set inside of the
1952 // loop. Happens if people set a loop-exit flag; then test the flag
1953 // in the loop to break the loop, then test is again outside of the
1954 // loop to determine which way the loop exited.
1955 // Loop predicate If node connects to Bool node through Opaque1 node.
1956 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) {
1957 // Since this code is highly unlikely, we lazily build the worklist
1958 // of such Nodes to go split.
1959 if (!split_if_set) {
1960 ResourceArea *area = Thread::current()->resource_area();
1961 split_if_set = new Node_List(area);
1962 }
1963 split_if_set->push(use);
1964 }
1965 if (use->is_Bool()) {
1966 if (!split_bool_set) {
1967 ResourceArea *area = Thread::current()->resource_area();
1968 split_bool_set = new Node_List(area);
1969 }
1970 split_bool_set->push(use);
1971 }
1972 if (use->Opcode() == Op_CreateEx) {
1973 if (!split_cex_set) {
1974 ResourceArea *area = Thread::current()->resource_area();
1975 split_cex_set = new Node_List(area);
1976 }
1977 split_cex_set->push(use);
1978 }
1979
1980
1981 // Get "block" use is in
1982 uint idx = 0;
1983 while( use->in(idx) != old ) idx++;
1984 Node *prev = use->is_CFG() ? use : get_ctrl(use);
1985 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
1986 Node *cfg = prev->_idx >= new_counter
1987 ? prev->in(2)
1988 : idom(prev);
1989 if( use->is_Phi() ) // Phi use is in prior block
1990 cfg = prev->in(idx); // NOT in block of Phi itself
1991 if (cfg->is_top()) { // Use is dead?
1992 _igvn.replace_input_of(use, idx, C->top());
1993 continue;
1994 }
1995
1996 while(!outer_loop->is_member(get_loop(cfg))) {
1997 prev = cfg;
1998 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
1999 }
2000 // If the use occurs after merging several exits from the loop, then
2001 // old value must have dominated all those exits. Since the same old
2002 // value was used on all those exits we did not need a Phi at this
2003 // merge point. NOW we do need a Phi here. Each loop exit value
2004 // is now merged with the peeled body exit; each exit gets its own
2005 // private Phi and those Phis need to be merged here.
2006 Node *phi;
2007 if( prev->is_Region() ) {
2008 if( idx == 0 ) { // Updating control edge?
2009 phi = prev; // Just use existing control
2010 } else { // Else need a new Phi
2011 phi = PhiNode::make( prev, old );
2012 // Now recursively fix up the new uses of old!
2013 for( uint i = 1; i < prev->req(); i++ ) {
2014 worklist.push(phi); // Onto worklist once for each 'old' input
2015 }
2016 }
2017 } else {
2018 // Get new RegionNode merging old and new loop exits
2019 prev = old_new[prev->_idx];
2020 assert( prev, "just made this in step 7" );
2021 if( idx == 0) { // Updating control edge?
2022 phi = prev; // Just use existing control
2023 } else { // Else need a new Phi
2024 // Make a new Phi merging data values properly
2025 phi = PhiNode::make( prev, old );
2026 phi->set_req( 1, nnn );
2027 }
2028 }
2029 // If inserting a new Phi, check for prior hits
2030 if( idx != 0 ) {
2031 Node *hit = _igvn.hash_find_insert(phi);
2032 if( hit == NULL ) {
2033 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2034 } else { // or
2035 // Remove the new phi from the graph and use the hit
2036 _igvn.remove_dead_node(phi);
2037 phi = hit; // Use existing phi
2038 }
2039 set_ctrl(phi, prev);
2040 }
2041 // Make 'use' use the Phi instead of the old loop body exit value
2042 _igvn.replace_input_of(use, idx, phi);
2043 if( use->_idx >= new_counter ) { // If updating new phis
2044 // Not needed for correctness, but prevents a weak assert
2045 // in AddPNode from tripping (when we end up with different
2046 // base & derived Phis that will become the same after
2047 // IGVN does CSE).
2048 Node *hit = _igvn.hash_find_insert(use);
2049 if( hit ) // Go ahead and re-hash for hits.
2050 _igvn.replace_node( use, hit );
2051 }
2052
2053 // If 'use' was in the loop-exit block, it now needs to be sunk
2054 // below the post-loop merge point.
2055 sink_use( use, prev );
2056 }
2057 }
2058 }
2059
2060 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2061 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2062 Node_List& extra_data_nodes) {
2063 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2064 CountedLoopNode* cl = head->as_CountedLoop();
2065 Node* l = cl->outer_loop();
2066 Node* tail = cl->outer_loop_tail();
2067 IfNode* le = cl->outer_loop_end();
2068 Node* sfpt = cl->outer_safepoint();
2069 CountedLoopEndNode* cle = cl->loopexit();
2070 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2071 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2072 Node* cle_out = cle->proj_out(false);
2073
2074 Node* new_sfpt = NULL;
2075 Node* new_cle_out = cle_out->clone();
2076 old_new.map(cle_out->_idx, new_cle_out);
2077 if (mode == CloneIncludesStripMined) {
2078 // clone outer loop body
2079 Node* new_l = l->clone();
2080 Node* new_tail = tail->clone();
2081 IfNode* new_le = le->clone()->as_If();
2082 new_sfpt = sfpt->clone();
2083
2084 set_loop(new_l, outer_loop->_parent);
2085 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2086 set_loop(new_cle_out, outer_loop->_parent);
2087 set_idom(new_cle_out, new_cle, dd);
2088 set_loop(new_sfpt, outer_loop->_parent);
2089 set_idom(new_sfpt, new_cle_out, dd);
2090 set_loop(new_le, outer_loop->_parent);
2091 set_idom(new_le, new_sfpt, dd);
2092 set_loop(new_tail, outer_loop->_parent);
2093 set_idom(new_tail, new_le, dd);
2094 set_idom(new_cl, new_l, dd);
2095
2096 old_new.map(l->_idx, new_l);
2097 old_new.map(tail->_idx, new_tail);
2098 old_new.map(le->_idx, new_le);
2099 old_new.map(sfpt->_idx, new_sfpt);
2100
2101 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2102 new_l->set_req(0, new_l);
2103 new_tail->set_req(0, new_le);
2104 new_le->set_req(0, new_sfpt);
2105 new_sfpt->set_req(0, new_cle_out);
2106 new_cle_out->set_req(0, new_cle);
2107 new_cl->set_req(LoopNode::EntryControl, new_l);
2108
2109 _igvn.register_new_node_with_optimizer(new_l);
2110 _igvn.register_new_node_with_optimizer(new_tail);
2111 _igvn.register_new_node_with_optimizer(new_le);
2112 } else {
2113 Node *newhead = old_new[loop->_head->_idx];
2114 newhead->as_Loop()->clear_strip_mined();
2115 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2116 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2117 }
2118 // Look at data node that were assigned a control in the outer
2119 // loop: they are kept in the outer loop by the safepoint so start
2120 // from the safepoint node's inputs.
2121 IdealLoopTree* outer_loop = get_loop(l);
2122 Node_Stack stack(2);
2123 stack.push(sfpt, 1);
2124 uint new_counter = C->unique();
2125 while (stack.size() > 0) {
2126 Node* n = stack.node();
2127 uint i = stack.index();
2128 while (i < n->req() &&
2129 (n->in(i) == NULL ||
2130 !has_ctrl(n->in(i)) ||
2131 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2132 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2133 i++;
2134 }
2135 if (i < n->req()) {
2136 stack.set_index(i+1);
2137 stack.push(n->in(i), 0);
2138 } else {
2139 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2140 Node* m = n == sfpt ? new_sfpt : n->clone();
2141 if (m != NULL) {
2142 for (uint i = 0; i < n->req(); i++) {
2143 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) {
2144 m->set_req(i, old_new[m->in(i)->_idx]);
2145 }
2146 }
2147 } else {
2148 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2149 }
2150 if (n != sfpt) {
2151 extra_data_nodes.push(n);
2152 _igvn.register_new_node_with_optimizer(m);
2153 assert(get_ctrl(n) == cle_out, "what other control?");
2154 set_ctrl(m, new_cle_out);
2155 old_new.map(n->_idx, m);
2156 }
2157 stack.pop();
2158 }
2159 }
2160 if (mode == CloneIncludesStripMined) {
2161 _igvn.register_new_node_with_optimizer(new_sfpt);
2162 _igvn.register_new_node_with_optimizer(new_cle_out);
2163 }
2164 } else {
2165 Node *newhead = old_new[loop->_head->_idx];
2166 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2167 }
2168 }
2169
2170 //------------------------------clone_loop-------------------------------------
2171 //
2172 // C L O N E A L O O P B O D Y
2173 //
2174 // This is the basic building block of the loop optimizations. It clones an
2175 // entire loop body. It makes an old_new loop body mapping; with this mapping
2176 // you can find the new-loop equivalent to an old-loop node. All new-loop
2177 // nodes are exactly equal to their old-loop counterparts, all edges are the
2178 // same. All exits from the old-loop now have a RegionNode that merges the
2179 // equivalent new-loop path. This is true even for the normal "loop-exit"
2180 // condition. All uses of loop-invariant old-loop values now come from (one
2181 // or more) Phis that merge their new-loop equivalents.
2182 //
2183 // This operation leaves the graph in an illegal state: there are two valid
2184 // control edges coming from the loop pre-header to both loop bodies. I'll
2185 // definitely have to hack the graph after running this transform.
2186 //
2187 // From this building block I will further edit edges to perform loop peeling
2188 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2189 //
2190 // Parameter side_by_size_idom:
2191 // When side_by_size_idom is NULL, the dominator tree is constructed for
2192 // the clone loop to dominate the original. Used in construction of
2193 // pre-main-post loop sequence.
2194 // When nonnull, the clone and original are side-by-side, both are
2195 // dominated by the side_by_side_idom node. Used in construction of
2196 // unswitched loops.
2197 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2198 CloneLoopMode mode, Node* side_by_side_idom) {
2199
2200 LoopNode* head = loop->_head->as_Loop();
2201 head->verify_strip_mined(1);
2202
2203 if (C->do_vector_loop() && PrintOpto) {
2204 const char* mname = C->method()->name()->as_quoted_ascii();
2205 if (mname != NULL) {
2206 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2207 }
2208 }
2209
2210 CloneMap& cm = C->clone_map();
2211 Dict* dict = cm.dict();
2212 if (C->do_vector_loop()) {
2213 cm.set_clone_idx(cm.max_gen()+1);
2214 #ifndef PRODUCT
2215 if (PrintOpto) {
2216 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2217 loop->dump_head();
2218 }
2219 #endif
2220 }
2221
2222 // Step 1: Clone the loop body. Make the old->new mapping.
2223 uint i;
2224 for( i = 0; i < loop->_body.size(); i++ ) {
2225 Node *old = loop->_body.at(i);
2226 Node *nnn = old->clone();
2227 old_new.map( old->_idx, nnn );
2228 if (C->do_vector_loop()) {
2229 cm.verify_insert_and_clone(old, nnn, cm.clone_idx());
2230 }
2231 _igvn.register_new_node_with_optimizer(nnn);
2232 }
2233
2234 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2235
2236 // Step 2: Fix the edges in the new body. If the old input is outside the
2237 // loop use it. If the old input is INside the loop, use the corresponding
2238 // new node instead.
2239 for( i = 0; i < loop->_body.size(); i++ ) {
2240 Node *old = loop->_body.at(i);
2241 Node *nnn = old_new[old->_idx];
2242 // Fix CFG/Loop controlling the new node
2243 if (has_ctrl(old)) {
2244 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2245 } else {
2246 set_loop(nnn, outer_loop->_parent);
2247 if (old->outcnt() > 0) {
2248 set_idom( nnn, old_new[idom(old)->_idx], dd );
2249 }
2250 }
2251 // Correct edges to the new node
2252 for( uint j = 0; j < nnn->req(); j++ ) {
2253 Node *n = nnn->in(j);
2254 if( n ) {
2255 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n );
2256 if( loop->is_member( old_in_loop ) )
2257 nnn->set_req(j, old_new[n->_idx]);
2258 }
2259 }
2260 _igvn.hash_find_insert(nnn);
2261 }
2262
2263 ResourceArea *area = Thread::current()->resource_area();
2264 Node_List extra_data_nodes(area);
2265 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2266
2267 // Step 3: Now fix control uses. Loop varying control uses have already
2268 // been fixed up (as part of all input edges in Step 2). Loop invariant
2269 // control uses must be either an IfFalse or an IfTrue. Make a merge
2270 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2271 // refer to this.
2272 Node_List worklist(area);
2273 uint new_counter = C->unique();
2274 for( i = 0; i < loop->_body.size(); i++ ) {
2275 Node* old = loop->_body.at(i);
2276 if( !old->is_CFG() ) continue;
2277
2278 // Copy uses to a worklist, so I can munge the def-use info
2279 // with impunity.
2280 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2281 worklist.push(old->fast_out(j));
2282
2283 while( worklist.size() ) { // Visit all uses
2284 Node *use = worklist.pop();
2285 if (!has_node(use)) continue; // Ignore dead nodes
2286 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2287 if( !loop->is_member( use_loop ) && use->is_CFG() ) {
2288 // Both OLD and USE are CFG nodes here.
2289 assert( use->is_Proj(), "" );
2290 Node* nnn = old_new[old->_idx];
2291
2292 Node* newuse = NULL;
2293 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2294 CountedLoopNode* cl = head->as_CountedLoop();
2295 CountedLoopEndNode* cle = cl->loopexit();
2296 Node* cle_out = cle->proj_out_or_null(false);
2297 if (use == cle_out) {
2298 IfNode* le = cl->outer_loop_end();
2299 use = le->proj_out(false);
2300 use_loop = get_loop(use);
2301 if (mode == CloneIncludesStripMined) {
2302 nnn = old_new[le->_idx];
2303 } else {
2304 newuse = old_new[cle_out->_idx];
2305 }
2306 }
2307 }
2308 if (newuse == NULL) {
2309 newuse = use->clone();
2310 }
2311
2312 // Clone the loop exit control projection
2313 if (C->do_vector_loop()) {
2314 cm.verify_insert_and_clone(use, newuse, cm.clone_idx());
2315 }
2316 newuse->set_req(0,nnn);
2317 _igvn.register_new_node_with_optimizer(newuse);
2318 set_loop(newuse, use_loop);
2319 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2320
2321 // We need a Region to merge the exit from the peeled body and the
2322 // exit from the old loop body.
2323 RegionNode *r = new RegionNode(3);
2324 // Map the old use to the new merge point
2325 old_new.map( use->_idx, r );
2326 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use));
2327 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" );
2328
2329 // The original user of 'use' uses 'r' instead.
2330 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2331 Node* useuse = use->last_out(l);
2332 _igvn.rehash_node_delayed(useuse);
2333 uint uses_found = 0;
2334 if( useuse->in(0) == use ) {
2335 useuse->set_req(0, r);
2336 uses_found++;
2337 if( useuse->is_CFG() ) {
2338 assert( dom_depth(useuse) > dd_r, "" );
2339 set_idom(useuse, r, dom_depth(useuse));
2340 }
2341 }
2342 for( uint k = 1; k < useuse->req(); k++ ) {
2343 if( useuse->in(k) == use ) {
2344 useuse->set_req(k, r);
2345 uses_found++;
2346 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2347 assert(dom_depth(useuse) > dd_r , "");
2348 set_idom(useuse, r, dom_depth(useuse));
2349 }
2350 }
2351 }
2352 l -= uses_found; // we deleted 1 or more copies of this edge
2353 }
2354
2355 // Now finish up 'r'
2356 r->set_req( 1, newuse );
2357 r->set_req( 2, use );
2358 _igvn.register_new_node_with_optimizer(r);
2359 set_loop(r, use_loop);
2360 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r);
2361 } // End of if a loop-exit test
2362 }
2363 }
2364
2365 // Step 4: If loop-invariant use is not control, it must be dominated by a
2366 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2367 // there if needed. Make a Phi there merging old and new used values.
2368 Node_List *split_if_set = NULL;
2369 Node_List *split_bool_set = NULL;
2370 Node_List *split_cex_set = NULL;
2371 for( i = 0; i < loop->_body.size(); i++ ) {
2372 Node* old = loop->_body.at(i);
2373 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2374 split_bool_set, split_cex_set, worklist, new_counter,
2375 mode);
2376 }
2377
2378 for (i = 0; i < extra_data_nodes.size(); i++) {
2379 Node* old = extra_data_nodes.at(i);
2380 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2381 split_bool_set, split_cex_set, worklist, new_counter,
2382 mode);
2383 }
2384
2385 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2386 // the loop uses a condition set in the loop. The original IF probably
2387 // takes control from one or more OLD Regions (which in turn get from NEW
2388 // Regions). In any case, there will be a set of Phis for each merge point
2389 // from the IF up to where the original BOOL def exists the loop.
2390 if (split_if_set) {
2391 while (split_if_set->size()) {
2392 Node *iff = split_if_set->pop();
2393 if (iff->in(1)->is_Phi()) {
2394 Node *b = clone_iff(iff->in(1)->as_Phi(), loop);
2395 _igvn.replace_input_of(iff, 1, b);
2396 }
2397 }
2398 }
2399 if (split_bool_set) {
2400 while (split_bool_set->size()) {
2401 Node *b = split_bool_set->pop();
2402 Node *phi = b->in(1);
2403 assert(phi->is_Phi(), "");
2404 CmpNode *cmp = clone_bool((PhiNode*)phi, loop);
2405 _igvn.replace_input_of(b, 1, cmp);
2406 }
2407 }
2408 if (split_cex_set) {
2409 while (split_cex_set->size()) {
2410 Node *b = split_cex_set->pop();
2411 assert(b->in(0)->is_Region(), "");
2412 assert(b->in(1)->is_Phi(), "");
2413 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2414 split_up(b, b->in(0), NULL);
2415 }
2416 }
2417
2418 }
2419
2420
2421 //---------------------- stride_of_possible_iv -------------------------------------
2422 // Looks for an iff/bool/comp with one operand of the compare
2423 // being a cycle involving an add and a phi,
2424 // with an optional truncation (left-shift followed by a right-shift)
2425 // of the add. Returns zero if not an iv.
2426 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2427 Node* trunc1 = NULL;
2428 Node* trunc2 = NULL;
2429 const TypeInt* ttype = NULL;
2430 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) {
2431 return 0;
2432 }
2433 BoolNode* bl = iff->in(1)->as_Bool();
2434 Node* cmp = bl->in(1);
2435 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2436 return 0;
2437 }
2438 // Must have an invariant operand
2439 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2440 return 0;
2441 }
2442 Node* add2 = NULL;
2443 Node* cmp1 = cmp->in(1);
2444 if (cmp1->is_Phi()) {
2445 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2446 Node* phi = cmp1;
2447 for (uint i = 1; i < phi->req(); i++) {
2448 Node* in = phi->in(i);
2449 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2450 &trunc1, &trunc2, &ttype);
2451 if (add && add->in(1) == phi) {
2452 add2 = add->in(2);
2453 break;
2454 }
2455 }
2456 } else {
2457 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2458 Node* addtrunc = cmp1;
2459 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2460 &trunc1, &trunc2, &ttype);
2461 if (add && add->in(1)->is_Phi()) {
2462 Node* phi = add->in(1);
2463 for (uint i = 1; i < phi->req(); i++) {
2464 if (phi->in(i) == addtrunc) {
2465 add2 = add->in(2);
2466 break;
2467 }
2468 }
2469 }
2470 }
2471 if (add2 != NULL) {
2472 const TypeInt* add2t = _igvn.type(add2)->is_int();
2473 if (add2t->is_con()) {
2474 return add2t->get_con();
2475 }
2476 }
2477 return 0;
2478 }
2479
2480
2481 //---------------------- stay_in_loop -------------------------------------
2482 // Return the (unique) control output node that's in the loop (if it exists.)
2483 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2484 Node* unique = NULL;
2485 if (!n) return NULL;
2486 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2487 Node* use = n->fast_out(i);
2488 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2489 if (unique != NULL) {
2490 return NULL;
2491 }
2492 unique = use;
2493 }
2494 }
2495 return unique;
2496 }
2497
2498 //------------------------------ register_node -------------------------------------
2499 // Utility to register node "n" with PhaseIdealLoop
2500 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) {
2501 _igvn.register_new_node_with_optimizer(n);
2502 loop->_body.push(n);
2503 if (n->is_CFG()) {
2504 set_loop(n, loop);
2505 set_idom(n, pred, ddepth);
2506 } else {
2507 set_ctrl(n, pred);
2508 }
2509 }
2510
2511 //------------------------------ proj_clone -------------------------------------
2512 // Utility to create an if-projection
2513 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2514 ProjNode* c = p->clone()->as_Proj();
2515 c->set_req(0, iff);
2516 return c;
2517 }
2518
2519 //------------------------------ short_circuit_if -------------------------------------
2520 // Force the iff control output to be the live_proj
2521 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2522 guarantee(live_proj != NULL, "null projection");
2523 int proj_con = live_proj->_con;
2524 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2525 Node *con = _igvn.intcon(proj_con);
2526 set_ctrl(con, C->root());
2527 if (iff) {
2528 iff->set_req(1, con);
2529 }
2530 return con;
2531 }
2532
2533 //------------------------------ insert_if_before_proj -------------------------------------
2534 // Insert a new if before an if projection (* - new node)
2535 //
2536 // before
2537 // if(test)
2538 // / \
2539 // v v
2540 // other-proj proj (arg)
2541 //
2542 // after
2543 // if(test)
2544 // / \
2545 // / v
2546 // | * proj-clone
2547 // v |
2548 // other-proj v
2549 // * new_if(relop(cmp[IU](left,right)))
2550 // / \
2551 // v v
2552 // * new-proj proj
2553 // (returned)
2554 //
2555 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2556 IfNode* iff = proj->in(0)->as_If();
2557 IdealLoopTree *loop = get_loop(proj);
2558 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2559 int ddepth = dom_depth(proj);
2560
2561 _igvn.rehash_node_delayed(iff);
2562 _igvn.rehash_node_delayed(proj);
2563
2564 proj->set_req(0, NULL); // temporary disconnect
2565 ProjNode* proj2 = proj_clone(proj, iff);
2566 register_node(proj2, loop, iff, ddepth);
2567
2568 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2569 register_node(cmp, loop, proj2, ddepth);
2570
2571 BoolNode* bol = new BoolNode(cmp, relop);
2572 register_node(bol, loop, proj2, ddepth);
2573
2574 int opcode = iff->Opcode();
2575 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2576 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
2577 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
2578 register_node(new_if, loop, proj2, ddepth);
2579
2580 proj->set_req(0, new_if); // reattach
2581 set_idom(proj, new_if, ddepth);
2582
2583 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2584 guarantee(new_exit != NULL, "null exit node");
2585 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2586
2587 return new_exit;
2588 }
2589
2590 //------------------------------ insert_region_before_proj -------------------------------------
2591 // Insert a region before an if projection (* - new node)
2592 //
2593 // before
2594 // if(test)
2595 // / |
2596 // v |
2597 // proj v
2598 // other-proj
2599 //
2600 // after
2601 // if(test)
2602 // / |
2603 // v |
2604 // * proj-clone v
2605 // | other-proj
2606 // v
2607 // * new-region
2608 // |
2609 // v
2610 // * dum_if
2611 // / \
2612 // v \
2613 // * dum-proj v
2614 // proj
2615 //
2616 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2617 IfNode* iff = proj->in(0)->as_If();
2618 IdealLoopTree *loop = get_loop(proj);
2619 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2620 int ddepth = dom_depth(proj);
2621
2622 _igvn.rehash_node_delayed(iff);
2623 _igvn.rehash_node_delayed(proj);
2624
2625 proj->set_req(0, NULL); // temporary disconnect
2626 ProjNode* proj2 = proj_clone(proj, iff);
2627 register_node(proj2, loop, iff, ddepth);
2628
2629 RegionNode* reg = new RegionNode(2);
2630 reg->set_req(1, proj2);
2631 register_node(reg, loop, iff, ddepth);
2632
2633 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt);
2634 register_node(dum_if, loop, reg, ddepth);
2635
2636 proj->set_req(0, dum_if); // reattach
2637 set_idom(proj, dum_if, ddepth);
2638
2639 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
2640 register_node(dum_proj, loop, dum_if, ddepth);
2641
2642 return reg;
2643 }
2644
2645 //------------------------------ insert_cmpi_loop_exit -------------------------------------
2646 // Clone a signed compare loop exit from an unsigned compare and
2647 // insert it before the unsigned cmp on the stay-in-loop path.
2648 // All new nodes inserted in the dominator tree between the original
2649 // if and it's projections. The original if test is replaced with
2650 // a constant to force the stay-in-loop path.
2651 //
2652 // This is done to make sure that the original if and it's projections
2653 // still dominate the same set of control nodes, that the ctrl() relation
2654 // from data nodes to them is preserved, and that their loop nesting is
2655 // preserved.
2656 //
2657 // before
2658 // if(i <u limit) unsigned compare loop exit
2659 // / |
2660 // v v
2661 // exit-proj stay-in-loop-proj
2662 //
2663 // after
2664 // if(stay-in-loop-const) original if
2665 // / |
2666 // / v
2667 // / if(i < limit) new signed test
2668 // / / |
2669 // / / v
2670 // / / if(i <u limit) new cloned unsigned test
2671 // / / / |
2672 // v v v |
2673 // region |
2674 // | |
2675 // dum-if |
2676 // / | |
2677 // ether | |
2678 // v v
2679 // exit-proj stay-in-loop-proj
2680 //
2681 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
2682 const bool Signed = true;
2683 const bool Unsigned = false;
2684
2685 BoolNode* bol = if_cmpu->in(1)->as_Bool();
2686 if (bol->_test._test != BoolTest::lt) return NULL;
2687 CmpNode* cmpu = bol->in(1)->as_Cmp();
2688 if (cmpu->Opcode() != Op_CmpU) return NULL;
2689 int stride = stride_of_possible_iv(if_cmpu);
2690 if (stride == 0) return NULL;
2691
2692 Node* lp_proj = stay_in_loop(if_cmpu, loop);
2693 guarantee(lp_proj != NULL, "null loop node");
2694
2695 ProjNode* lp_continue = lp_proj->as_Proj();
2696 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
2697
2698 Node* limit = NULL;
2699 if (stride > 0) {
2700 limit = cmpu->in(2);
2701 } else {
2702 limit = _igvn.makecon(TypeInt::ZERO);
2703 set_ctrl(limit, C->root());
2704 }
2705 // Create a new region on the exit path
2706 RegionNode* reg = insert_region_before_proj(lp_exit);
2707 guarantee(reg != NULL, "null region node");
2708
2709 // Clone the if-cmpu-true-false using a signed compare
2710 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
2711 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
2712 reg->add_req(cmpi_exit);
2713
2714 // Clone the if-cmpu-true-false
2715 BoolTest::mask rel_u = bol->_test._test;
2716 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
2717 reg->add_req(cmpu_exit);
2718
2719 // Force original if to stay in loop.
2720 short_circuit_if(if_cmpu, lp_continue);
2721
2722 return cmpi_exit->in(0)->as_If();
2723 }
2724
2725 //------------------------------ remove_cmpi_loop_exit -------------------------------------
2726 // Remove a previously inserted signed compare loop exit.
2727 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
2728 Node* lp_proj = stay_in_loop(if_cmp, loop);
2729 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
2730 stay_in_loop(lp_proj, loop)->is_If() &&
2731 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
2732 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
2733 set_ctrl(con, C->root());
2734 if_cmp->set_req(1, con);
2735 }
2736
2737 //------------------------------ scheduled_nodelist -------------------------------------
2738 // Create a post order schedule of nodes that are in the
2739 // "member" set. The list is returned in "sched".
2740 // The first node in "sched" is the loop head, followed by
2741 // nodes which have no inputs in the "member" set, and then
2742 // followed by the nodes that have an immediate input dependence
2743 // on a node in "sched".
2744 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
2745
2746 assert(member.test(loop->_head->_idx), "loop head must be in member set");
2747 Arena *a = Thread::current()->resource_area();
2748 VectorSet visited(a);
2749 Node_Stack nstack(a, loop->_body.size());
2750
2751 Node* n = loop->_head; // top of stack is cached in "n"
2752 uint idx = 0;
2753 visited.set(n->_idx);
2754
2755 // Initially push all with no inputs from within member set
2756 for(uint i = 0; i < loop->_body.size(); i++ ) {
2757 Node *elt = loop->_body.at(i);
2758 if (member.test(elt->_idx)) {
2759 bool found = false;
2760 for (uint j = 0; j < elt->req(); j++) {
2761 Node* def = elt->in(j);
2762 if (def && member.test(def->_idx) && def != elt) {
2763 found = true;
2764 break;
2765 }
2766 }
2767 if (!found && elt != loop->_head) {
2768 nstack.push(n, idx);
2769 n = elt;
2770 assert(!visited.test(n->_idx), "not seen yet");
2771 visited.set(n->_idx);
2772 }
2773 }
2774 }
2775
2776 // traverse out's that are in the member set
2777 while (true) {
2778 if (idx < n->outcnt()) {
2779 Node* use = n->raw_out(idx);
2780 idx++;
2781 if (!visited.test_set(use->_idx)) {
2782 if (member.test(use->_idx)) {
2783 nstack.push(n, idx);
2784 n = use;
2785 idx = 0;
2786 }
2787 }
2788 } else {
2789 // All outputs processed
2790 sched.push(n);
2791 if (nstack.is_empty()) break;
2792 n = nstack.node();
2793 idx = nstack.index();
2794 nstack.pop();
2795 }
2796 }
2797 }
2798
2799
2800 //------------------------------ has_use_in_set -------------------------------------
2801 // Has a use in the vector set
2802 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
2803 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2804 Node* use = n->fast_out(j);
2805 if (vset.test(use->_idx)) {
2806 return true;
2807 }
2808 }
2809 return false;
2810 }
2811
2812
2813 //------------------------------ has_use_internal_to_set -------------------------------------
2814 // Has use internal to the vector set (ie. not in a phi at the loop head)
2815 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
2816 Node* head = loop->_head;
2817 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2818 Node* use = n->fast_out(j);
2819 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
2820 return true;
2821 }
2822 }
2823 return false;
2824 }
2825
2826
2827 //------------------------------ clone_for_use_outside_loop -------------------------------------
2828 // clone "n" for uses that are outside of loop
2829 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
2830 int cloned = 0;
2831 assert(worklist.size() == 0, "should be empty");
2832 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2833 Node* use = n->fast_out(j);
2834 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
2835 worklist.push(use);
2836 }
2837 }
2838 while( worklist.size() ) {
2839 Node *use = worklist.pop();
2840 if (!has_node(use) || use->in(0) == C->top()) continue;
2841 uint j;
2842 for (j = 0; j < use->req(); j++) {
2843 if (use->in(j) == n) break;
2844 }
2845 assert(j < use->req(), "must be there");
2846
2847 // clone "n" and insert it between the inputs of "n" and the use outside the loop
2848 Node* n_clone = n->clone();
2849 _igvn.replace_input_of(use, j, n_clone);
2850 cloned++;
2851 Node* use_c;
2852 if (!use->is_Phi()) {
2853 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
2854 } else {
2855 // Use in a phi is considered a use in the associated predecessor block
2856 use_c = use->in(0)->in(j);
2857 }
2858 set_ctrl(n_clone, use_c);
2859 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
2860 get_loop(use_c)->_body.push(n_clone);
2861 _igvn.register_new_node_with_optimizer(n_clone);
2862 #if !defined(PRODUCT)
2863 if (TracePartialPeeling) {
2864 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
2865 }
2866 #endif
2867 }
2868 return cloned;
2869 }
2870
2871
2872 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
2873 // clone "n" for special uses that are in the not_peeled region.
2874 // If these def-uses occur in separate blocks, the code generator
2875 // marks the method as not compilable. For example, if a "BoolNode"
2876 // is in a different basic block than the "IfNode" that uses it, then
2877 // the compilation is aborted in the code generator.
2878 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
2879 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
2880 if (n->is_Phi() || n->is_Load()) {
2881 return;
2882 }
2883 assert(worklist.size() == 0, "should be empty");
2884 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2885 Node* use = n->fast_out(j);
2886 if ( not_peel.test(use->_idx) &&
2887 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
2888 use->in(1) == n) {
2889 worklist.push(use);
2890 }
2891 }
2892 if (worklist.size() > 0) {
2893 // clone "n" and insert it between inputs of "n" and the use
2894 Node* n_clone = n->clone();
2895 loop->_body.push(n_clone);
2896 _igvn.register_new_node_with_optimizer(n_clone);
2897 set_ctrl(n_clone, get_ctrl(n));
2898 sink_list.push(n_clone);
2899 not_peel <<= n_clone->_idx; // add n_clone to not_peel set.
2900 #if !defined(PRODUCT)
2901 if (TracePartialPeeling) {
2902 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
2903 }
2904 #endif
2905 while( worklist.size() ) {
2906 Node *use = worklist.pop();
2907 _igvn.rehash_node_delayed(use);
2908 for (uint j = 1; j < use->req(); j++) {
2909 if (use->in(j) == n) {
2910 use->set_req(j, n_clone);
2911 }
2912 }
2913 }
2914 }
2915 }
2916
2917
2918 //------------------------------ insert_phi_for_loop -------------------------------------
2919 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
2920 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
2921 Node *phi = PhiNode::make(lp, back_edge_val);
2922 phi->set_req(LoopNode::EntryControl, lp_entry_val);
2923 // Use existing phi if it already exists
2924 Node *hit = _igvn.hash_find_insert(phi);
2925 if( hit == NULL ) {
2926 _igvn.register_new_node_with_optimizer(phi);
2927 set_ctrl(phi, lp);
2928 } else {
2929 // Remove the new phi from the graph and use the hit
2930 _igvn.remove_dead_node(phi);
2931 phi = hit;
2932 }
2933 _igvn.replace_input_of(use, idx, phi);
2934 }
2935
2936 #ifdef ASSERT
2937 //------------------------------ is_valid_loop_partition -------------------------------------
2938 // Validate the loop partition sets: peel and not_peel
2939 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
2940 VectorSet& not_peel ) {
2941 uint i;
2942 // Check that peel_list entries are in the peel set
2943 for (i = 0; i < peel_list.size(); i++) {
2944 if (!peel.test(peel_list.at(i)->_idx)) {
2945 return false;
2946 }
2947 }
2948 // Check at loop members are in one of peel set or not_peel set
2949 for (i = 0; i < loop->_body.size(); i++ ) {
2950 Node *def = loop->_body.at(i);
2951 uint di = def->_idx;
2952 // Check that peel set elements are in peel_list
2953 if (peel.test(di)) {
2954 if (not_peel.test(di)) {
2955 return false;
2956 }
2957 // Must be in peel_list also
2958 bool found = false;
2959 for (uint j = 0; j < peel_list.size(); j++) {
2960 if (peel_list.at(j)->_idx == di) {
2961 found = true;
2962 break;
2963 }
2964 }
2965 if (!found) {
2966 return false;
2967 }
2968 } else if (not_peel.test(di)) {
2969 if (peel.test(di)) {
2970 return false;
2971 }
2972 } else {
2973 return false;
2974 }
2975 }
2976 return true;
2977 }
2978
2979 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
2980 // Ensure a use outside of loop is of the right form
2981 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
2982 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2983 return (use->is_Phi() &&
2984 use_c->is_Region() && use_c->req() == 3 &&
2985 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
2986 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
2987 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
2988 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
2989 }
2990
2991 //------------------------------ is_valid_clone_loop_form -------------------------------------
2992 // Ensure that all uses outside of loop are of the right form
2993 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
2994 uint orig_exit_idx, uint clone_exit_idx) {
2995 uint len = peel_list.size();
2996 for (uint i = 0; i < len; i++) {
2997 Node *def = peel_list.at(i);
2998
2999 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3000 Node *use = def->fast_out(j);
3001 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
3002 if (!loop->is_member(get_loop(use_c))) {
3003 // use is not in the loop, check for correct structure
3004 if (use->in(0) == def) {
3005 // Okay
3006 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
3007 return false;
3008 }
3009 }
3010 }
3011 }
3012 return true;
3013 }
3014 #endif
3015
3016 //------------------------------ partial_peel -------------------------------------
3017 // Partially peel (aka loop rotation) the top portion of a loop (called
3018 // the peel section below) by cloning it and placing one copy just before
3019 // the new loop head and the other copy at the bottom of the new loop.
3020 //
3021 // before after where it came from
3022 //
3023 // stmt1 stmt1
3024 // loop: stmt2 clone
3025 // stmt2 if condA goto exitA clone
3026 // if condA goto exitA new_loop: new
3027 // stmt3 stmt3 clone
3028 // if !condB goto loop if condB goto exitB clone
3029 // exitB: stmt2 orig
3030 // stmt4 if !condA goto new_loop orig
3031 // exitA: goto exitA
3032 // exitB:
3033 // stmt4
3034 // exitA:
3035 //
3036 // Step 1: find the cut point: an exit test on probable
3037 // induction variable.
3038 // Step 2: schedule (with cloning) operations in the peel
3039 // section that can be executed after the cut into
3040 // the section that is not peeled. This may need
3041 // to clone operations into exit blocks. For
3042 // instance, a reference to A[i] in the not-peel
3043 // section and a reference to B[i] in an exit block
3044 // may cause a left-shift of i by 2 to be placed
3045 // in the peel block. This step will clone the left
3046 // shift into the exit block and sink the left shift
3047 // from the peel to the not-peel section.
3048 // Step 3: clone the loop, retarget the control, and insert
3049 // phis for values that are live across the new loop
3050 // head. This is very dependent on the graph structure
3051 // from clone_loop. It creates region nodes for
3052 // exit control and associated phi nodes for values
3053 // flow out of the loop through that exit. The region
3054 // node is dominated by the clone's control projection.
3055 // So the clone's peel section is placed before the
3056 // new loop head, and the clone's not-peel section is
3057 // forms the top part of the new loop. The original
3058 // peel section forms the tail of the new loop.
3059 // Step 4: update the dominator tree and recompute the
3060 // dominator depth.
3061 //
3062 // orig
3063 //
3064 // stmt1
3065 // |
3066 // v
3067 // loop predicate
3068 // |
3069 // v
3070 // loop<----+
3071 // | |
3072 // stmt2 |
3073 // | |
3074 // v |
3075 // ifA |
3076 // / | |
3077 // v v |
3078 // false true ^ <-- last_peel
3079 // / | |
3080 // / ===|==cut |
3081 // / stmt3 | <-- first_not_peel
3082 // / | |
3083 // | v |
3084 // v ifB |
3085 // exitA: / \ |
3086 // / \ |
3087 // v v |
3088 // false true |
3089 // / \ |
3090 // / ----+
3091 // |
3092 // v
3093 // exitB:
3094 // stmt4
3095 //
3096 //
3097 // after clone loop
3098 //
3099 // stmt1
3100 // |
3101 // v
3102 // loop predicate
3103 // / \
3104 // clone / \ orig
3105 // / \
3106 // / \
3107 // v v
3108 // +---->loop loop<----+
3109 // | | | |
3110 // | stmt2 stmt2 |
3111 // | | | |
3112 // | v v |
3113 // | ifA ifA |
3114 // | | \ / | |
3115 // | v v v v |
3116 // ^ true false false true ^ <-- last_peel
3117 // | | ^ \ / | |
3118 // | cut==|== \ \ / ===|==cut |
3119 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3120 // | | dom | | | |
3121 // | v \ 1v v2 v |
3122 // | ifB regionA ifB |
3123 // | / \ | / \ |
3124 // | / \ v / \ |
3125 // | v v exitA: v v |
3126 // | true false false true |
3127 // | / ^ \ / \ |
3128 // +---- \ \ / ----+
3129 // dom \ /
3130 // \ 1v v2
3131 // regionB
3132 // |
3133 // v
3134 // exitB:
3135 // stmt4
3136 //
3137 //
3138 // after partial peel
3139 //
3140 // stmt1
3141 // |
3142 // v
3143 // loop predicate
3144 // /
3145 // clone / orig
3146 // / TOP
3147 // / \
3148 // v v
3149 // TOP->loop loop----+
3150 // | | |
3151 // stmt2 stmt2 |
3152 // | | |
3153 // v v |
3154 // ifA ifA |
3155 // | \ / | |
3156 // v v v v |
3157 // true false false true | <-- last_peel
3158 // | ^ \ / +------|---+
3159 // +->newloop \ \ / === ==cut | |
3160 // | stmt3 \ \ / TOP | |
3161 // | | dom | | stmt3 | | <-- first_not_peel
3162 // | v \ 1v v2 v | |
3163 // | ifB regionA ifB ^ v
3164 // | / \ | / \ | |
3165 // | / \ v / \ | |
3166 // | v v exitA: v v | |
3167 // | true false false true | |
3168 // | / ^ \ / \ | |
3169 // | | \ \ / v | |
3170 // | | dom \ / TOP | |
3171 // | | \ 1v v2 | |
3172 // ^ v regionB | |
3173 // | | | | |
3174 // | | v ^ v
3175 // | | exitB: | |
3176 // | | stmt4 | |
3177 // | +------------>-----------------+ |
3178 // | |
3179 // +-----------------<---------------------+
3180 //
3181 //
3182 // final graph
3183 //
3184 // stmt1
3185 // |
3186 // v
3187 // loop predicate
3188 // |
3189 // v
3190 // stmt2 clone
3191 // |
3192 // v
3193 // ........> ifA clone
3194 // : / |
3195 // dom / |
3196 // : v v
3197 // : false true
3198 // : | |
3199 // : | v
3200 // : | newloop<-----+
3201 // : | | |
3202 // : | stmt3 clone |
3203 // : | | |
3204 // : | v |
3205 // : | ifB |
3206 // : | / \ |
3207 // : | v v |
3208 // : | false true |
3209 // : | | | |
3210 // : | v stmt2 |
3211 // : | exitB: | |
3212 // : | stmt4 v |
3213 // : | ifA orig |
3214 // : | / \ |
3215 // : | / \ |
3216 // : | v v |
3217 // : | false true |
3218 // : | / \ |
3219 // : v v -----+
3220 // RegionA
3221 // |
3222 // v
3223 // exitA
3224 //
3225 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3226
3227 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3228 if (!loop->_head->is_Loop()) {
3229 return false; }
3230
3231 LoopNode *head = loop->_head->as_Loop();
3232
3233 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3234 return false;
3235 }
3236
3237 // Check for complex exit control
3238 for(uint ii = 0; ii < loop->_body.size(); ii++ ) {
3239 Node *n = loop->_body.at(ii);
3240 int opc = n->Opcode();
3241 if (n->is_Call() ||
3242 opc == Op_Catch ||
3243 opc == Op_CatchProj ||
3244 opc == Op_Jump ||
3245 opc == Op_JumpProj) {
3246 #if !defined(PRODUCT)
3247 if (TracePartialPeeling) {
3248 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3249 }
3250 #endif
3251 return false;
3252 }
3253 }
3254
3255 int dd = dom_depth(head);
3256
3257 // Step 1: find cut point
3258
3259 // Walk up dominators to loop head looking for first loop exit
3260 // which is executed on every path thru loop.
3261 IfNode *peel_if = NULL;
3262 IfNode *peel_if_cmpu = NULL;
3263
3264 Node *iff = loop->tail();
3265 while( iff != head ) {
3266 if( iff->is_If() ) {
3267 Node *ctrl = get_ctrl(iff->in(1));
3268 if (ctrl->is_top()) return false; // Dead test on live IF.
3269 // If loop-varying exit-test, check for induction variable
3270 if( loop->is_member(get_loop(ctrl)) &&
3271 loop->is_loop_exit(iff) &&
3272 is_possible_iv_test(iff)) {
3273 Node* cmp = iff->in(1)->in(1);
3274 if (cmp->Opcode() == Op_CmpI) {
3275 peel_if = iff->as_If();
3276 } else {
3277 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3278 peel_if_cmpu = iff->as_If();
3279 }
3280 }
3281 }
3282 iff = idom(iff);
3283 }
3284 // Prefer signed compare over unsigned compare.
3285 IfNode* new_peel_if = NULL;
3286 if (peel_if == NULL) {
3287 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) {
3288 return false; // No peel point found
3289 }
3290 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3291 if (new_peel_if == NULL) {
3292 return false; // No peel point found
3293 }
3294 peel_if = new_peel_if;
3295 }
3296 Node* last_peel = stay_in_loop(peel_if, loop);
3297 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3298 if (first_not_peeled == NULL || first_not_peeled == head) {
3299 return false;
3300 }
3301
3302 #if !defined(PRODUCT)
3303 if (TraceLoopOpts) {
3304 tty->print("PartialPeel ");
3305 loop->dump_head();
3306 }
3307
3308 if (TracePartialPeeling) {
3309 tty->print_cr("before partial peel one iteration");
3310 Node_List wl;
3311 Node* t = head->in(2);
3312 while (true) {
3313 wl.push(t);
3314 if (t == head) break;
3315 t = idom(t);
3316 }
3317 while (wl.size() > 0) {
3318 Node* tt = wl.pop();
3319 tt->dump();
3320 if (tt == last_peel) tty->print_cr("-- cut --");
3321 }
3322 }
3323 #endif
3324 ResourceArea *area = Thread::current()->resource_area();
3325 VectorSet peel(area);
3326 VectorSet not_peel(area);
3327 Node_List peel_list(area);
3328 Node_List worklist(area);
3329 Node_List sink_list(area);
3330
3331 // Set of cfg nodes to peel are those that are executable from
3332 // the head through last_peel.
3333 assert(worklist.size() == 0, "should be empty");
3334 worklist.push(head);
3335 peel.set(head->_idx);
3336 while (worklist.size() > 0) {
3337 Node *n = worklist.pop();
3338 if (n != last_peel) {
3339 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3340 Node* use = n->fast_out(j);
3341 if (use->is_CFG() &&
3342 loop->is_member(get_loop(use)) &&
3343 !peel.test_set(use->_idx)) {
3344 worklist.push(use);
3345 }
3346 }
3347 }
3348 }
3349
3350 // Set of non-cfg nodes to peel are those that are control
3351 // dependent on the cfg nodes.
3352 uint i;
3353 for(i = 0; i < loop->_body.size(); i++ ) {
3354 Node *n = loop->_body.at(i);
3355 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3356 if (peel.test(n_c->_idx)) {
3357 peel.set(n->_idx);
3358 } else {
3359 not_peel.set(n->_idx);
3360 }
3361 }
3362
3363 // Step 2: move operations from the peeled section down into the
3364 // not-peeled section
3365
3366 // Get a post order schedule of nodes in the peel region
3367 // Result in right-most operand.
3368 scheduled_nodelist(loop, peel, peel_list );
3369
3370 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3371
3372 // For future check for too many new phis
3373 uint old_phi_cnt = 0;
3374 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3375 Node* use = head->fast_out(j);
3376 if (use->is_Phi()) old_phi_cnt++;
3377 }
3378
3379 #if !defined(PRODUCT)
3380 if (TracePartialPeeling) {
3381 tty->print_cr("\npeeled list");
3382 }
3383 #endif
3384
3385 // Evacuate nodes in peel region into the not_peeled region if possible
3386 uint new_phi_cnt = 0;
3387 uint cloned_for_outside_use = 0;
3388 for (i = 0; i < peel_list.size();) {
3389 Node* n = peel_list.at(i);
3390 #if !defined(PRODUCT)
3391 if (TracePartialPeeling) n->dump();
3392 #endif
3393 bool incr = true;
3394 if ( !n->is_CFG() ) {
3395
3396 if ( has_use_in_set(n, not_peel) ) {
3397
3398 // If not used internal to the peeled region,
3399 // move "n" from peeled to not_peeled region.
3400
3401 if ( !has_use_internal_to_set(n, peel, loop) ) {
3402
3403 // if not pinned and not a load (which maybe anti-dependent on a store)
3404 // and not a CMove (Matcher expects only bool->cmove).
3405 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) {
3406 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist );
3407 sink_list.push(n);
3408 peel >>= n->_idx; // delete n from peel set.
3409 not_peel <<= n->_idx; // add n to not_peel set.
3410 peel_list.remove(i);
3411 incr = false;
3412 #if !defined(PRODUCT)
3413 if (TracePartialPeeling) {
3414 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3415 n->_idx, get_ctrl(n)->_idx);
3416 }
3417 #endif
3418 }
3419 } else {
3420 // Otherwise check for special def-use cases that span
3421 // the peel/not_peel boundary such as bool->if
3422 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist );
3423 new_phi_cnt++;
3424 }
3425 }
3426 }
3427 if (incr) i++;
3428 }
3429
3430 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) {
3431 #if !defined(PRODUCT)
3432 if (TracePartialPeeling) {
3433 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3434 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F');
3435 }
3436 #endif
3437 if (new_peel_if != NULL) {
3438 remove_cmpi_loop_exit(new_peel_if, loop);
3439 }
3440 // Inhibit more partial peeling on this loop
3441 assert(!head->is_partial_peel_loop(), "not partial peeled");
3442 head->mark_partial_peel_failed();
3443 if (cloned_for_outside_use > 0) {
3444 // Terminate this round of loop opts because
3445 // the graph outside this loop was changed.
3446 C->set_major_progress();
3447 return true;
3448 }
3449 return false;
3450 }
3451
3452 // Step 3: clone loop, retarget control, and insert new phis
3453
3454 // Create new loop head for new phis and to hang
3455 // the nodes being moved (sinked) from the peel region.
3456 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3457 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3458 _igvn.register_new_node_with_optimizer(new_head);
3459 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3460 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3461 set_loop(new_head, loop);
3462 loop->_body.push(new_head);
3463 not_peel.set(new_head->_idx);
3464 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3465 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3466
3467 while (sink_list.size() > 0) {
3468 Node* n = sink_list.pop();
3469 set_ctrl(n, new_head);
3470 }
3471
3472 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3473
3474 clone_loop(loop, old_new, dd, IgnoreStripMined);
3475
3476 const uint clone_exit_idx = 1;
3477 const uint orig_exit_idx = 2;
3478 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop");
3479
3480 Node* head_clone = old_new[head->_idx];
3481 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3482 Node* orig_tail_clone = head_clone->in(2);
3483
3484 // Add phi if "def" node is in peel set and "use" is not
3485
3486 for(i = 0; i < peel_list.size(); i++ ) {
3487 Node *def = peel_list.at(i);
3488 if (!def->is_CFG()) {
3489 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3490 Node *use = def->fast_out(j);
3491 if (has_node(use) && use->in(0) != C->top() &&
3492 (!peel.test(use->_idx) ||
3493 (use->is_Phi() && use->in(0) == head)) ) {
3494 worklist.push(use);
3495 }
3496 }
3497 while( worklist.size() ) {
3498 Node *use = worklist.pop();
3499 for (uint j = 1; j < use->req(); j++) {
3500 Node* n = use->in(j);
3501 if (n == def) {
3502
3503 // "def" is in peel set, "use" is not in peel set
3504 // or "use" is in the entry boundary (a phi) of the peel set
3505
3506 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3507
3508 if ( loop->is_member(get_loop( use_c )) ) {
3509 // use is in loop
3510 if (old_new[use->_idx] != NULL) { // null for dead code
3511 Node* use_clone = old_new[use->_idx];
3512 _igvn.replace_input_of(use, j, C->top());
3513 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3514 }
3515 } else {
3516 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3517 // use is not in the loop, check if the live range includes the cut
3518 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3519 if (not_peel.test(lp_if->_idx)) {
3520 assert(j == orig_exit_idx, "use from original loop");
3521 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3522 }
3523 }
3524 }
3525 }
3526 }
3527 }
3528 }
3529
3530 // Step 3b: retarget control
3531
3532 // Redirect control to the new loop head if a cloned node in
3533 // the not_peeled region has control that points into the peeled region.
3534 // This necessary because the cloned peeled region will be outside
3535 // the loop.
3536 // from to
3537 // cloned-peeled <---+
3538 // new_head_clone: | <--+
3539 // cloned-not_peeled in(0) in(0)
3540 // orig-peeled
3541
3542 for(i = 0; i < loop->_body.size(); i++ ) {
3543 Node *n = loop->_body.at(i);
3544 if (!n->is_CFG() && n->in(0) != NULL &&
3545 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
3546 Node* n_clone = old_new[n->_idx];
3547 _igvn.replace_input_of(n_clone, 0, new_head_clone);
3548 }
3549 }
3550
3551 // Backedge of the surviving new_head (the clone) is original last_peel
3552 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
3553
3554 // Cut first node in original not_peel set
3555 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
3556 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
3557 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
3558
3559 // Copy head_clone back-branch info to original head
3560 // and remove original head's loop entry and
3561 // clone head's back-branch
3562 _igvn.rehash_node_delayed(head); // Multiple edge updates
3563 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
3564 head->set_req(LoopNode::LoopBackControl, C->top());
3565 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
3566
3567 // Similarly modify the phis
3568 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
3569 Node* use = head->fast_out(k);
3570 if (use->is_Phi() && use->outcnt() > 0) {
3571 Node* use_clone = old_new[use->_idx];
3572 _igvn.rehash_node_delayed(use); // Multiple edge updates
3573 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
3574 use->set_req(LoopNode::LoopBackControl, C->top());
3575 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
3576 }
3577 }
3578
3579 // Step 4: update dominator tree and dominator depth
3580
3581 set_idom(head, orig_tail_clone, dd);
3582 recompute_dom_depth();
3583
3584 // Inhibit more partial peeling on this loop
3585 new_head_clone->set_partial_peel_loop();
3586 C->set_major_progress();
3587 loop->record_for_igvn();
3588
3589 #if !defined(PRODUCT)
3590 if (TracePartialPeeling) {
3591 tty->print_cr("\nafter partial peel one iteration");
3592 Node_List wl(area);
3593 Node* t = last_peel;
3594 while (true) {
3595 wl.push(t);
3596 if (t == head_clone) break;
3597 t = idom(t);
3598 }
3599 while (wl.size() > 0) {
3600 Node* tt = wl.pop();
3601 if (tt == head) tty->print_cr("orig head");
3602 else if (tt == new_head_clone) tty->print_cr("new head");
3603 else if (tt == head_clone) tty->print_cr("clone head");
3604 tt->dump();
3605 }
3606 }
3607 #endif
3608 return true;
3609 }
3610
3611 //------------------------------reorg_offsets----------------------------------
3612 // Reorganize offset computations to lower register pressure. Mostly
3613 // prevent loop-fallout uses of the pre-incremented trip counter (which are
3614 // then alive with the post-incremented trip counter forcing an extra
3615 // register move)
3616 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) {
3617 // Perform it only for canonical counted loops.
3618 // Loop's shape could be messed up by iteration_split_impl.
3619 if (!loop->_head->is_CountedLoop())
3620 return;
3621 if (!loop->_head->as_Loop()->is_valid_counted_loop())
3622 return;
3623
3624 CountedLoopNode *cl = loop->_head->as_CountedLoop();
3625 CountedLoopEndNode *cle = cl->loopexit();
3626 Node *exit = cle->proj_out(false);
3627 Node *phi = cl->phi();
3628
3629 // Check for the special case of folks using the pre-incremented
3630 // trip-counter on the fall-out path (forces the pre-incremented
3631 // and post-incremented trip counter to be live at the same time).
3632 // Fix this by adjusting to use the post-increment trip counter.
3633
3634 bool progress = true;
3635 while (progress) {
3636 progress = false;
3637 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) {
3638 Node* use = phi->fast_out(i); // User of trip-counter
3639 if (!has_ctrl(use)) continue;
3640 Node *u_ctrl = get_ctrl(use);
3641 if (use->is_Phi()) {
3642 u_ctrl = NULL;
3643 for (uint j = 1; j < use->req(); j++)
3644 if (use->in(j) == phi)
3645 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j));
3646 }
3647 IdealLoopTree *u_loop = get_loop(u_ctrl);
3648 // Look for loop-invariant use
3649 if (u_loop == loop) continue;
3650 if (loop->is_member(u_loop)) continue;
3651 // Check that use is live out the bottom. Assuming the trip-counter
3652 // update is right at the bottom, uses of of the loop middle are ok.
3653 if (dom_lca(exit, u_ctrl) != exit) continue;
3654 // Hit! Refactor use to use the post-incremented tripcounter.
3655 // Compute a post-increment tripcounter.
3656 Node *opaq = new Opaque2Node( C, cle->incr() );
3657 register_new_node(opaq, exit);
3658 Node *neg_stride = _igvn.intcon(-cle->stride_con());
3659 set_ctrl(neg_stride, C->root());
3660 Node *post = new AddINode( opaq, neg_stride);
3661 register_new_node(post, exit);
3662 _igvn.rehash_node_delayed(use);
3663 for (uint j = 1; j < use->req(); j++) {
3664 if (use->in(j) == phi)
3665 use->set_req(j, post);
3666 }
3667 // Since DU info changed, rerun loop
3668 progress = true;
3669 break;
3670 }
3671 }
3672
3673 }